ACKNOWLEDGEMENTWe are rather infused by Prof. S.S .mane Sir who put us in cradle of engineering studies & evaluated us to this end & mean of our project report without his guidance, we are sure to be orphan in vast ocean of subject. Ultimately no tongue could describe deep sense of co-operation and ready nature to help us even in our minute details of the write up of the project report.We would like to thank Prof. S. Y. Saptasagar Head of automobile department for his valuable guidance & encouragement.Further we are thankful to all teaching and non teaching staff of AUTOMOBILE DEPARTMENT for their co-operation during seminar report work. We are very grateful to those who in the form of books and conveyed guidance in this project report work.Finally we thank our colleagues, friends and all other who helped us directly or indirectly.

Sr. No.NameRoll No.

1Mr. Patil Sukhdev Govind02

2Mr. Shelar Shubham Vijay04

3Mr. Sutar Aditya Ashok05

4Mr. Swami Pavan Sadashiv06

Sr. No.IndexPage No.

1List of Figure 5

2Introduction8

3Hydraulic Pump9

3.1Gear pump-10

External gear pump11

Internal Gear pump14

3.2Vane pump17

3.3Lobe Pump19

3.4Screw Pump22

3.5Piston Pump25

4Control Components29

4.1Direction Control valve-30

Poppet Valve31

Sliding-Spool Valve33

Two-Way Valve34

Three-Way Valve35

Four-Way Valves37

4.2Pressure Control Valve-45

Pressure Relief Valve45

Direct Type Relief Valve46

Unloading Valve47

Sequence Valve48

Counterbalance Valve49

Pressure reducing valve50

4.3Flow control valve-51

Gate Valve52

Plug or glove valve53

Butterfly valve54

Ball Valve55

Balance valve56

5Actuator57

5.1Cylinder-57

Single Acting57

Double Acting57

Differential Cylinder58

Piston Type Cylinder58

Cushioned Cylinder60

Lockout Cylinder61

5.2Hydraulic Motor-62

Gear type motor63

Vane type motor64

6Fitting & connector66

Threaded Connector66

Flared connector67

Flexible hose coupling70

Reusable Coupling71

7Cutting Procedure72

Vane Pump72

Gear pump73

Double acting cylinder74

Single acting cylinder74

Flow control valve75

Hoses75

8Tools & Equipment76

9Costing78

10Conclusion79

11References80

List of figureSr. No.NamePage No.

Fig 3.1Gears of pump09

Fig 3.2Anexploded viewof an external gear pump11

Fig 3.3Working of external gear pump12

Fig 3.4Anexploded viewof an internal gear (Gerotor) pump14

Fig 3.5Internal gear (Gerotor) pump14

Fig 3.6Working of Internal gear pump15

Fig 3.7Working of Vane Pumps17

Fig 3.8Working of lobe Pumps20

Fig 3.9Screw pump22

Fig 3.10Piston Pump25

Fig 4.12 / 2 DCV Poppet Design32

Fig 4.2Symbol of 2/2 poppet valve ( Check valve )32

Fig 4.3Spool type 2 / 2 DCV34

Fig 4.44.9 2 /3 DCV36

Fig 4.5Two- position, four way DCV31

Fig 4.62 / 4 DCV with manually operated39

Fig 4.72 / 4 DCV with manually operated by hand lever39

Fig 4.8Working of solenoid to shift spool of valve40

Fig 4.9Pilot actuated DCV42

Fig 4.10Symbol for Pneumatic actuated 2 / 4 DCV43

Fig 4.11Pressure Relief Valve46

Fig 4.12Unloading Valve47

Fig 4.13Sequence valve48

Fig 4.14Counter Balance Valve49

Fig 4.15Pressure Reducing Valve50

Fig 4.16Gate valve52

Fig 4.17Plug or glove valve53

Fig 4.18Butterfly valve54

Fig 4.19Ball valve55

Fig 4.20Balanced valves56

Fig 5.1Piston Type cylinder58

Fig 5.2Double-acting, piston-type cylinder59

Fig 5.3Cushioned, actuating cylinder60

Fig 5.4Basic operations of a hydraulic motor62

Fig 5.5Gear-type motor63

Fig 5.6Vane-type motor64

Fig 5.7Pressure differential on a vane-type motor64

Fig 5.8Rocker arms pushing vanes in a pump65

Fig 6.1Threaded-pipe connectors66

Fig 6.2Flared tube connector67

Fig 6.3Flared tube Fittings69

Fig 6.4Field-attachable couplings70

Fig 6.5permanently attached couplings71

Fig 7.1Cutting & grinding of vane pump72

Fig 7.12Dismantling & cutting of gear pump73

Fig 7.3cutting of flow control valve75

2) INTRODUCTIONHydraulic machinery is very essential in industries for improving quality of parts & reduces the time of manufacturing of new parts. Hydraulic machine are used in industries, & it can be hydrostatic or Hydrodynamic. Hydraulic pump is a mechanical source of Pollster that converts mechanical power into Hydraulic energy, (Hydrostatic energy i.e. flow, pressure). It generates Row of with rough power to overcome pressure inducted by the load at the pump outlet. When a Hydraulic pump operates its creates a vacuum at the pump inlet, which forces liquid from the reservoir into the inlet line to the pump & by mechanical action delivers this liquid to the pump outlet & forces it into the Hydraulic systems. Hydrostatic pumps are positive displacement pumps which Hydrodynamic pumps can be fixed displacement in which the displacement (How thought the pumps per rotation of the pump) cannot be adjusted or variable displacement pumps, which have a more complicated construction that allows the displacement to be adjusted. Although, Hydrodynamic pumps are more frequent in day to day life. Hydrostatics pumps which are of various types of work on the principle of Pascals low. It states that the increases in pressure in pressure at one point of the enclosed liquid in equilibrium of rest are transmitted equally, to all other points of the liquid, unless the effect of gravity is neglected.

3. Hydraulic pump

Fig. 3.1 Gears of pump

Hydraulic pumps are used in hydraulic drive systems and can be hydrostatic or hydrodynamic. A hydraulic pump is a mechanical source of power that converts mechanical power into hydraulic energy (hydrostatic energy i.e. flow, pressure). It generates flow with enough power to overcome pressure induced by the load at the pump outlet. When a hydraulic pump operates, it creates a vacuum at the pump inlet, which forces liquid from the reservoir into the inlet line to the pump and by mechanical action delivers this liquid to the pump outlet and forces it into the hydraulic system. Hydrostatic pumps are positive displacement pumps while hydrodynamic pumps can be fixed displacement pumps, in which the displacement (flow through the pump per rotation of the pump) cannot be adjusted or variable displacement pumps, which have a more complicated construction that allows the displacement to be adjusted. Although, hydrodynamic pumps are more frequent in day to day life. Hydrostatics pump which are of various types works on the principle of Pascals law. It states that the increase in pressure at one point of the enclosed liquid in equilibrium of rest is transmitted equally to all other points of the liquid, unless the effect of gravity is neglected.(in case of statics)

Hydraulic pump types3.1 Gear pumps:-Gear pumps (with external teeth) (fixed displacement) are simple and economical pumps. The swept volume or displacement of gear pumps for hydraulics will be between about 1 and 200 milliliters. They have the lowest volumetric efficiency (nv= 90%) of all three basic pump types (gear, vane and piston pumps).These pumps create pressure through the meshing of the gear teeth, which forces fluid around the gears to pressurize the outlet side. For lubrication, the gear pump uses a small amount of oil from the pressurized side of the gears, bleeds this through the (typically) hydrodynamic bearings, and vents the same oil either to the low pressure side of the gears, or through a dedicated drain port on the pump housing. Some gear pumps can be quite noisy, compared to other types, but modern gear pumps are highly reliable and much quieter than older models. This is in part due to designs incorporating split gears, helical gear teeth and higher precision or quality tooth profiles that mesh and unmesh more smoothly, reducing pressure ripple and related detrimental problems. Another positive attribute of the gear pump, is that catastrophic breakdown is a lot less common than in most other types of hydraulic pumps. This is because the gears gradually wear down the housing and/or main bushings, reducing the volumetric efficiency of the pump gradually until it is all but useless. This often happens long before wear causes the unit to seize or break down.

1) External gear pump

Fig 3.2 Anexploded viewof an external gear pumpExternal gear pumps are a popular pumping principle and are often used as lubrication pumps in machine tools, in fluid power transfer units, and as oil pumps in engines.External gear pumps can come in single or double (two sets of gears) pump configurations with spur (shown), helical, and herringbone gears. Helical and herringbone gears typically offer a smoother flow than spur gears, although all gear types are relatively smooth. Large-capacity external gear pumps typically use helical or herringbone gears. Small external gear pumps usually operate at 1750 or 3450 rpm and larger models operate at speeds up to 640 rpm. External gear pumps have close tolerances and shaft support on both sides of the gears. This allows them to run to pressures beyond 3,000 PSI / 200 BAR, making them well suited for use in hydraulics. With four bearings in the liquid and tight tolerances, they are not well suited to handling abrasive or extreme high temperature applications.Tighter internal clearances provide for a more reliable measure of liquid passing through a pump and for greater flow control. Because of this, external gear pumps are popular for precise transfer and metering applications involving polymers, fuels, and chemical additives.Working of External Gear Pumps

Fig 3.3 Working of external gear pumpExternal gear pumps are similar in pumping action to internal gear pumps in that two gears come into and out of mesh to produce flow. However, the external gear pump uses two identical gears rotating against each other -- one gear is driven by a motor and it in turn drives the other gear. Each gear is supported by a shaft with bearings on both sides of the gear.1. As the gears come out of mesh, they create expanding volume on the inlet side of the pump. Liquid flows into the cavity and is trapped by the gear teeth as they rotate.2. Liquid travels around the interior of the casing in the pockets between the teeth and the casing -- it does not pass between the gears.3. Finally, the meshing of the gears forces liquid through the outlet port under pressure.Because the gears are supported on both sides, external gear pumps are quiet-running and are routinely used for high-pressure applications such as hydraulic applications. With no overhung bearing loads, the rotor shaft can't deflect and cause premature wear.

Advantages High speed High pressure No overhung bearing loads Relatively quiet operation Design accommodates wide variety of materials

Disadvantages Four bushings in liquid area No solids allowed Fixed End ClearancesMaterials of Construction / Configuration OptionsAs the following list indicates, rotary pumps can be constructed in a wide variety of materials. By precisely matching the materials of construction with the liquid, superior life cycle performance will result.External gear pumps in particular can be engineered to handle even the most aggressive corrosive liquids. While external gear pumps are commonly found in cast iron, newer materials are allowing these pumps to handle liquids such as sulfuric acid, sodium hypochlorite, ferric chloride, sodium hydroxide, and hundreds of other corrosive liquids. Externals (head, casing, bracket)- Iron, ductile iron, steel, stainless steel, high alloys, composites (PPS, ETFE) Internals (shafts)- Steel, stainless steel, high alloys, alumina ceramic Internals (gears)- Steel, stainless steel, PTFE, composite (PPS) Bushing- Carbon, bronze, silicon carbide, needle bearings Shaft Seal- Packing, lip seal, component mechanical seal, magnetically-driven pump2) Internal gear pump

Fig. 3.4 Anexploded viewof an internal gear (Gerotor) pump

Fig. 3.5 Internal gear (Gerotor) pumpInternal gear pumps are exceptionally versatile. While they are often used on thin liquids such as solvents and fuel oil, they excel at efficiently pumping thick liquids such as asphalt, chocolate, and adhesives. The useful viscosity range of an internal gear pump is from 1cPs to over 1,000,000cP.In addition to their wide viscosity range, the pump has a wide temperature range as well, handling liquids up to 750F / 400C. This is due to the single point of end clearance (the distance between the ends of the rotor gear teeth and the head of the pump). This clearance is adjustable to accommodate high temperature, maximize efficiency for handling high viscosity liquids, and to accommodate for wear.The internal gear pump is non-pulsing, self-priming, and can run dry for short periods. They're also bi-rotational, meaning that the same pump can be used to load and unload vessels. Because internal gear pumps have only two moving parts, they are reliable, simple to operate, and easy to maintain.Working ofInternal Gear PumpsFig. 3.6 Working of Internal gear pump1. Liquid enters the suction port between the rotor (large exterior gear) and idler (small interior gear) teeth. The arrows indicate the direction of the pump and liquid.2. Liquid travels through the pump between the teeth of the "gear-within-a-gear" principle. The crescent shape divides the liquid and acts as a seal between the suction and discharge ports.3. The pump head is now nearly flooded, just prior to forcing the liquid out of the discharge port. Intermeshing gears of the idler and rotor form locked pockets for the liquid which assures volume control.4. Rotor and idler teeth mesh completely to form a seal equidistant from the discharge and suction ports. This seal forces the liquid out of the discharge port.

Advantages Only two moving parts Only one stuffing box Non-pulsating discharge Excellent for high-viscosity liquids Constant and even discharge regardless of pressure conditions Operates well in either direction Can be made to operate with one direction of flow with either rotation Low NPSH required Single adjustable end clearance Easy to maintain Flexible design offers application customization

Disadvantages Usually requires moderate speeds Medium pressure limitations One bearing runs in the product pumped Overhung load on shaft bearing

Materials of Construction / Configuration Options Externals (head, casing, bracket)- Cast iron, ductile iron, steel, stainless steel, Alloy 20, and higher alloys. Internals (rotor, idler)- Cast iron, ductile iron, steel, stainless steel, Alloy 20, and higher alloys. Bushing- Carbon graphite, bronze, silicon carbide, tungsten carbide, ceramic, colomony, and other specials materials as needed. Shaft Seal- Lip seals, component mechanical seals, industry-standard cartridge mechanical seals, gas barrier seals, magnetically-driven pumps.3.2 Vane Pump:-While vane pumps can handle moderate viscosity liquids, they excel at handling low viscosity liquids such as LP gas (propane), ammonia, solvents, alcohol, fuel oils, gasoline, and refrigerants. Vane pumps have no internal metal-to-metal contact and self-compensate for wear, enabling them to maintain peak performance on these non-lubricating liquids. Though efficiency drops quickly, they can be used up to 500 cPs / 2,300 SSU.Vane pumps are available in a number of vane configurations including sliding vane (left), flexible vane, swinging vane, rolling vane, and external vane. Vane pumps are noted for their dry priming, ease of maintenance, and good suction characteristics over the life of the pump. Moreover, vanes canusually handle fluid temperatures from -32C / -25F to 260C / 500F and differential pressures to 15 BAR / 200 PSI (higher for hydraulic vane pumps).Each type of vane pump offers unique advantages. For example, external vane pumps can handle large solids. Flexible vane pumps, on the other hand, can only handle small solids but create good vacuum. Sliding vane pumps can run dry for short periods of time and handle small amounts of vapor.Working of Vane Pumps Despite the different configurations, most vane pumps operate under the same general principle described below.

Fig 3.7 Working of Vane Pumps1. A slotted rotor is eccentrically supported in a cycloidal cam. The rotor is located close to the wall of the cam so a crescent-shaped cavity is formed. The rotor is sealed into the cam by two side plates. Vanes or blades fit within the slots of the impeller. As the rotor rotates (yellow arrow) and fluid enters the pump, centrifugal force, hydraulic pressure, and/or pushrods push the vanes to the walls of the housing. The tight seal among the vanes, rotor, cam, and side plate is the key to the good suction characteristics common to the vane pumping principle.2. The housing and cam force fluid into the pumping chamber through holes in the cam (small red arrow on the bottom of the pump). Fluid enters the pockets created by the vanes, rotor, cam, and side plate.3. As the rotor continues around, the vanes sweep the fluid to the opposite side of the crescent where it is squeezed through discharge holes of the cam as the vane approaches the point of the crescent (small red arrow on the side of the pump). Fluid then exits the discharge port.Advantages Handles thin liquids at relatively higher pressures Compensates for wear through vane extension Sometimes preferred for solvents, LPG Can run dry for short periods Can have one seal or stuffing box Develops good vacuum

Disadvantages Can have two stuffing boxes Complex housing and many parts Not suitable for high pressures Not suitable for high viscosity Not good with abrasives3.3 Lobe Pumps

Lobe pumps are used in a variety of industries including, pulp and paper, chemical, food, beverage, pharmaceutical, and biotechnology. They are popular in these diverse industries because they offer superb sanitary qualities, high efficiency, reliability, corrosion resistance, and good clean-in-place and sterilize-in place (CIP/SIP) characteristics.These pumps offer a variety of lobe options including single, bi-wing, tri-lobe (shown), and multi-lobe. Rotary lobe pumps are non-contacting and have large pumping chambers, allowing them to handle solids such as cherries or olives without damage. They are also used to handle slurries, pastes, and a wide variety of other liquids. If wetted, they offer self-priming performance. A gentle pumping action minimizes product degradation. They also offer reversible flows and can operate dry for long periods of time. Flow is relatively independent of changes in process pressure, so output is constant and continuous.Rotary lobe pumps range from industrial designs to sanitary designs. The sanitary designs break down further depending on the service and specific sanitary requirements. These requirements include 3-A, EHEDG, and USDA. The manufacturer can tell you which certifications, if any, their rotary lobe pump meets.

Working of Lobe Pumps Lobe pumps are similar to external gear pumps in operation in that fluid flows around the interior of the casing. Unlike external gear pumps, however, the lobes do not make contact. Lobe contact is prevented by external timing gears located in the gearbox. Pump shaft support bearings are located in the gearbox, and since the bearings are out of the pumped liquid, pressure is limited by bearing location and shaft deflection.

1. As the lobes come out of mesh, they create expanding volume on the inlet side of the pump. Liquid flows into the cavity and is trapped by the lobes as they rotate.2. Liquid travels around the interior of the casing in the pockets between the lobes and the casing -- it does not pass between the lobes.3. Finally, the meshing of the lobes forces liquid through the outlet port under pressure.Lobe pumps are frequently used in food applications because they handle solids without damaging the product. Particle size pumped can be much larger in lobe pumps than in other PD types. Since the lobes do not make contact, and clearances are not as close as in other PD pumps, this design handles low viscosity liquids with diminished performance. Loading characteristics are not as good as other designs, and suction ability is low. High-viscosity liquids require reduced speeds to achieve satisfactory performance. Reductions of 25% of rated speed and lower are common with high-viscosity liquids.Advantages Pass medium solids No metal-to-metal contact Superior CIP/SIP capabilities Long term dry run (with lubrication to seals)

Disadvantages Requires timing gears Requires two seals

3.4 Screw pump

Fig 3.9 Screw pumpAscrew pumpis a positive-displacement (PD) pump that uses one or several screws to move fluids or solids along the screw(s) axis. In its simplest form (theArchimedes' screw pump), a single screw rotates in a cylindrical cavity, thereby moving the material along the screw'sspindle. This ancient construction is still used in many low-tech applications, such asirrigation systemsand in agricultural machinery for transporting grain and other solids.Development of the screw pump has led to a variety of multiple-axis technologies where carefully crafted screws rotate in opposite directions or remains stationary within a cavity. The cavity can be profiled, thereby creating cavities where the pumped material is "trapped".In offshore and marine installations, a three-spindle screw pump is often used to pump high-pressureviscous fluids. Three screws drive the pumped liquid forth in a closed chamber. As the screws rotate in opposite directions the pumped liquid moves along the screws spindles.Three-spindle screw pumps are used for transport of viscous fluids with lubricating properties. They are suited for a variety of applications such asfuel-injection,oil burners, boosting,hydraulics, fuel,lubrication, circulating, feed and so on.Advantages of screw pump

1. Slow Speed, Simple and Rugged designProbably the main and overall advantage of a screw pump is its superb reliability. The simple design, open structure and slow rotation speed makes it a heavy duty pumps with minimal wears that operates for years without trouble.2. Pumps raw water with heavy solids and floating debrisBecause of the open structure and large passage between the flights a screw pump can pump raw sewage without the need for a coarse screen before the pump. Both floating debris and heavy solids are simply lifted up. This saves considerably on equipment costs for a coarse screen or maintenance!3. No collection sump required = minimum headA screw pump 'scoops' the water directly from the surface and does not need a collection sump. This keeps the pump head to a minimum.4. 'Gentle handling' of biological flockThe activated return sludge on STPs is a delicate biological substance. Because of the low rotational speed and large opening between the flights, screw pumps do not damage this biological flock (whereas the high speed rotating centrifugal pumps will completely shred the biological flock).5. Long lifetime (> 20-40 years)Screw pumps with typical lifetimes of between 20-40 years are not unusual.

6. Pump capacity is self-regulating with incoming levelWhen incoming water level goes down at dry weather flow the screw pump 'automatically' pumps less water. Ergo: no control system required to adapt pump performance.7. Easy maintenance (no 'high skilled' staff required)A screw pump requires very little maintenance. Compared to (submersed) centrifugal pumps it is next to nothing. Besides that no highly skilled maintenance staffs are required which makes this type of pump very suitable for remote locations.

8. Constant high efficiency with variable capacityThe efficiency-curve of a screw pump is flat on the top. Due to that efficiency characteristic, the screw pump offers even high efficiency when it works at 50% of its capacity.9. Can run without waterA screw pump can operate even when there is no water in the inlet. Therefore it is not necessary to install expensive measures (level control etc) to prevent 'dry-running'. The lower bearing does not need cooling.

3.5 Piston pumpAn axial piston pump has a number of pistons (usually an odd number) arranged in a circular array within ahousingwhich is commonly referred to as acylinder block,rotororbarrel. This cylinder block is driven to rotate about its axis of symmetry by an integral shaft that is, more or less, aligned with the pumping pistons (usuallyparallelbut not necessarily).No.Part Name

1Drive Shaft

2Swash Plate Servo Ball LH

3Swash Plate Servo Ball LH

4Retainer Plate

5Pistons

6Retainer Plate

7Ball Guide

8Block Spring

9Cylinder Block

10Valve Plate

11Shaft Bush

Fig 3.10 Piston PumpMating surfaces. One end of the cylinder block is convex and wears against a mating surface on a stationaryvalveplate. The inlet and outlet fluid of the pump pass through different parts of the sliding interface between the cylinder block and valve plate. The valve plate has two semi-circular ports that allow inlet of the operating fluid and exhaust of the outlet fluid respectively.

Protruding pistons. The pumping pistons protrude from the opposite end of the cylinder block. There are numerous configurations used for the exposed ends of the pistons but in all cases they bear against a cam. In variable displacement units, the cam is movable and commonly referred to as aswash plate,yokeorhanger. For conceptual purposes, the cam can be represented by a plane, the orientation of which, in combination with shaft rotation, provides the cam action that leads to piston reciprocation and thus pumping. The angle between a vector normal to the cam plane and the cylinder block axis of rotation, called thecam angle, is one variable that determines the displacement of the pump or the amount of fluid pumped per shaft revolution. Variable displacement units have the ability to vary the cam angle during operation whereas fixed displacement units do not. Reciprocating pistons. As the cylinder block rotates, the exposed ends of the pistons are constrained to follow the surface of the cam plane. Since the cam plane is at an angle to the axis of rotation, the pistons must reciprocate axially as they presses about the cylinder block axis. The axial motion of the pistons issinusoidal. During therisingportion of the piston's reciprocation cycle, the piston moves toward the valve plate. Also, during this time, the fluid trapped between theburiedend of the piston and the valve plate is vented to the pump's discharge port through one of the valve plate's semi-circular ports the dischargeport. As the piston moves toward the valve plate, fluid is pushed ordisplacedthrough the discharge port of the valve plate. Effect of precession. When the piston is at thetopof the reciprocation cycle (commonly referred to as top-dead-center or just TDC), theconnectionbetween the trapped fluid chamber and the pump's discharge port is closed. Shortly thereafter, that same chamber becomes open to the pump's inlet port. As the piston continues topressesabout the cylinder block axis, it moves away from the valve plate thereby increasing the volume of the trapped chamber. As this occurs, fluid enters the chamber from the pump's inlet to fill the void. This process continues until the piston reaches thebottomof the reciprocation cycle - commonly referred to as bottom-dead-center or BDC. At BDC, the connection between the pumping chamber and inlet port is closed. Shortly thereafter, the chamber becomes open to the discharge port again and the pumping cycle starts over. Variable displacement. In a variable displacement unit, if the vector normal to the cam plane (swash plate) is set parallel to the axis of rotation, there is no movement of the pistons in their cylinders. Thus there is no output. Movement of the swash plate controls pump output from zero to maximum. Pressure. In a typical pressure-compensated pump, the swash plate angle is adjusted through the action of a valve which uses pressure feedback so that the instantaneous pump output flow is exactly enough to maintain a designated pressure. If the load flow increases, pressure will momentarily decrease but the pressure-compensation valve will sense the decrease and then increase the swash plate angle to increase pump output flow so that the desired pressure is restored. In reality most systems use pressure as a control for this type of pump. The operating pressure reaches, say, 200 bar (20 MPa or 2900 psi) and the swash plate is driven towards zero angle (piston stroke nearly zero) and with the inherent leaks in the system allows the pump to stabilize at the delivery volume that maintains the set pressure. As demand increases the swash plate is moved to a greater angle, piston stroke increases and the volume of fluid increases; if the demand slackens the pressure will rise, and the pumped volume diminishes as the pressure rises. At maximum system pressure the output is once again almost zero. If the fluid demand increases beyond the capacity of the pump to deliver, the system pressure will drop to near zero. The swash plate angle will remain at the maximum allowed, and the pistons will operate at full stroke. This continues until system flow-demand eases and the pump's capacity is greater than demand. As the pressure rises the swash-plate angle modulates to try to not exceed the maximum pressure while meeting the flow demand.Advantages 1. Parameter High: Rated high pressure, high speed, large power-driven pump 2. Efficiency, volumetric efficiency is 95% of the total efficiency of about 90% 3. Long life 4. Variable convenient form for 5 More unit power and light weight 6. Piston main components are compressive stress, strength of materials can be fully utilized 7. Piston pumps have a wide pressure range, can reach high pressures and the pressure can be controlled without an impact on the rate of flow. Piston pumps have a continuous rate of discharge. Disadvantages Piston pumps cost more per unit to run compared to centrifugal and roller pumps. The mechanical parts are prone to wear, so the maintenance costs can be high. The valves must be resistant to abrasives for large solids to pass through. Piston pumps are heavy due to their large size and the weight of the crankshaft that drives the pump.

4) Control components One of the most important functions in any fluid power system is control. If control components are not properly selected, the entire system will fail to deliver the required output. Elements for the control of energy and other control in fluid power system are generally called Valves. It is important to know the primary function and operation of the various types of control components. This type of knowledge is not only required for a good functioning system, but it also leads to the discovery of innovative ways to improve a fluid power system for a given application

The selection of these control components not only involves the type, but also the size, the actuating method and remote control capability. There are 3 basic types of valves.1. Directional control valves

2. Pressure control valves

3. Flow control valves.

Directional control valves are essentially used for distribution of energy in a fluid power system. They establish the path through which a fluid traverses a given circuit. For example they control the direction of motion of a hydraulic cylinder or motor. These valves are used to control the start, stop and change in direction of flow of pressurized fluid.Pressure may gradually buildup due to decrease in fluid demand or due to sudden surge as valves opens or closes. Pressure control valves protect the system against such overpressure. Pressure relief valve, pressure reducing, sequence, unloading and counterbalance valve are different types of pressure control valves.In addition, fluid flow rate must be controlled in various lines of a hydraulic circuit. For example, the control of actuator speeds depends on flow rates. This type of control is accomplished through the use of flow control valves.4.1 Directional control valves

As the name implies directional control valves are used to control the direction of flow in a hydraulic circuit. They are used to extend, retract, position or reciprocate hydraulic cylinder and other components for linear motion. Valves contains ports that are external openings for fluid to enter and leave via connecting pipelines, The number of ports on a directional control valve (DCV ) is usually identified by the term way. For example, a valve with four ports is named as four-way valve.Directional control valves can be classified in a number of ways:1. According to type of construction :

Poppet valves Spool valves 2. According to number of working ports :

Two- way valves Three way valves Four- way valves. 3. According to number of Switching position:

Two position Three - position 4. According to Actuating mechanism:

Manual actuation Mechanical actuation Solenoid ( Electrical ) actuation Hydraulic ( Pilot ) actuation Pneumatic actuation Indirect actuation 1) According to type of construction1. Poppet Valves: Directional poppet valves consists of a housing bore in which one or more suitably formed seating elements ( moveable ) in the form of balls, cones are situated. When the operating pressure increases the valve becomes more tightly seated in this design. The main advantage of poppet valves is;

No Leakage as it provides absolute sealing. Long useful life, as there are no leakages of oil flows. May be used with even the highest pressures, as no hydraulic sticking (pressure dependent deformation) and leakages occurs in the valve.

The disadvantages of these valves are;

Large pressure losses due to short strokes Pressure collapse during switching phase due to negative overlap (connection of pump, actuator and tank at the same time). AUTOMOBILE DEPARTMENT BOARD MOUNTED HYDRAULIC DEVICES

P. V. P. I. T. BUDHGAON 32

72

P. V. P. I. T. BUDHGAON2 / 2 DCV (Poppet design) :-

Fig 4.1 2 / 2 DCV Poppet Design

Figure shows a ball poppet type 2 / 2 DCV. It is essentially a check valve as it allows free flow of fluid only in one direction (P to A) as the valve is opened hydraulically and hence the pump Port P is connected to port A as shown in fig b. In the other direction the valve is closed by the ball poppet (note the fluid pressure from A pushes the ball to its seat) and hence the flow from the port A is blocked .The symbol for this type of design is same as that of check valve.

No flow

Free flow

Fig. 4.2 Symbol of 2/2 poppet valve ( Check valve )

2. Spool valves: The spool valve consists of a spool which is a cylindrical member that has large- diameter lands machined to slide in a very close- fitting bore of the valve body. The spool valves are sealed along the clearance between the moving spool and the housing. The degree of sealing depends on the size of the gap, the viscosity of the fluid and especially on the level of pressure. Especially at high pressures (up to 350 bar) leakage occurs to such a extent that it must be taken into account when determining the system efficiency. The amount of leakage is primarily dependent on the gap between spool and housing. Hence as the operating pressure increases the gap must be reduced or the length of overlap increased. The radial clearance is usually less than 20 . The grooves between the lands provide the flow passage between ports.

2) According to number of working ports1. Two-way valve ( 2/ 2 DCV):

Fig 4.3 Spool type 2 / 2 DCVThe simplest type of directional control valve is a check valve which is a two way valve because it contains two ports. These valves are also called as on-off valves because they allow the fluid flow in only in one direction and the valve is normally closed. Two way valves is usually the spool or poppet design with the poppet design more common and are available as normally opened or normally closed valves. They are usually actuated by pilot (Hydraulic actuation) but manual, mechanical, solenoid actuated design are also available. Figure 4.3 above shows Spool type 2 / 2 DCV manually actuated. In Fig 4.3) the port P is blocked by the action of spring as the valve is UN actuated (absence of hand force). Hence the flow from port P to A is blocked. When actuated (Presence of hand force) the valve is opened, thereby connecting port P to A.

2) Three way valve: A directional control valve primary function is alternatively to pressurize and exhaust one working port is called three-way valve. Generally, these valves are used to operate single- acting cylinders. Three-way directional valves are available for manual, mechanical, pilot, solenoid actuation. These valves may be two-position, or three -position. Most commonly they have only two positions, but in some cases a neutral position may be needed. These valves are normally closed valves (i.e. the pump port is blocked when the valve is not operating). The three-way valve ports are inlet from the pump, working ports, and exhaust to tank. These ports are generally identified as follows: P= pressure (Pump) port; A or B = working port and T = tank port. Figure 4.4 (a) and (b) shows the two positions of the three way valve actuated manually by a push button.a. Spool position 1: When the valve is actuated, the spool moves towards left . In this position flow from pump enters the valve port P and flows out through the port A as shown by the straight- through line and arrow .In this position, port T is blocked by the spool.b. Spool position 0: when the valve is un-actuated by the absence of hand force, the valve assumes this position by the action of spring in this position, port P is blocked by the spool. Flow from the actuator can go to the tank from A to T as shown by straight through line and arrow.

Three way valve: P to A connected and T is blocked

Three way valve: P to A connected and T is blocked

Fig 4.4 2 /3 DCV

Symbol 2/ 3 DCV: -

0 1

3. Four - way DCV: - These valves are generally used to operate cylinders and fluid motors in both directions hydraulically. The four ways are Port P that is connected to pump, tank port T, and two working ports A and B connected to the actuator. The primary function of a four way valve is to alternately to pressurize and exhaust two working ports A & B. These valves are available with a choice of actuation, manual, mechanical, solenoid, pilot & pneumatic. Four-way valve comes with two or three position. One should note that the graphical symbol of the valve shows only one tank port even though the physical design may have two as it is only concerned with the function.

3.1. Three positions, four way valves: These type of DCV consists of three switching position. Most three- position valves have a variety of possible flow path configurations, but has identical flow path configuration in the actuated position (position 1 and position 2) and different spring centered flow paths. When left end of the valve is actuated, the valve will assume 1 position. In this position the port P to connected to working port A and working port B is connected to T (in some design P is connected to B, and A to T when left end is actuated ). Similarly when the right end is actuated, the valve will assume 2 positions. In this position port P is connected to B and working port A to T. When the valve is un-actuated, the valve will assume its center position due to the balancing opposing spring forces. It should be noted that a three-position valve is used whenever it is necessary to stop or hold a actuator at some intermediate position within its stroke range, or when multiple circuit or functions must be accomplished from one hydraulic power source.Three- position, four- way DCV have different variety of center configurations. The common varieties are the open center, closed center, tandem center, floating center, & regenerative center with open, closed and tandem are the three basic types A variety of center configurations provides greater flexibility for circuit design.

3.2 Two- position, Four way DCV: These valves are also used to operate double acting cylinder. These valves are also called as impulse valve as 2 / 4 DCV has only two switching positions, i.e. it has no mid position. These valves are used to reciprocate or hold and actuating cylinder in one position. They are used on machines where fast reciprocation cycles are needed. Since the valve actuator moves such a short distance to operate the valve from one position to the other, this design is used for punching, stamping and for other machines needing fast action. Fig a and b shows the two position of 2 / 4 DC

Fig 4.5 Two- position, four way DCV:Symbol

2

3) Actuation of Directional control valves: Directional control valves can be actuated by different methods.

1. Manually actuated Valve: A manually actuated DCV uses muscle power to actuate the spool. Manual actuators are hand lever, push button, pedals. The following symbols shows the DCV actuated manually

12Fig 4.6

Fig 4.6 shows the symbol of 2 / 4 DCV with manually operated by roller tappet to 1 and spring return to 2.

12Fig 4.7

Fig 4.7 shows the symbol of 2 / 4 DCV with manually operated by hand lever to 1 and spring return to 2. In the above two symbols the DCV spool is returned by springs which push the spool back to its initial position once the operating force has stopped e.g., letting go of the hand lever

2. Mechanical Actuation: The DCV spool can be actuated mechanically, by roller and cam, roller and plunger. The spool end contains the roller and the plunger or cam can be attached to the actuator (cylinder). When the cylinder reaches a specific position the DCV is actuated. The roller tappet connected to the spool is pushed in by a cam or plunger and presses on the spool to shift it either to right or left reversing the direction of flow to the cylinder. A spring is often used to bring the valve to its center configuration when deactuated.

3. Solenoid-actuated DCV :A very common way to actuate a spool valve is by using a solenoid is illustrated in Fig 4.8. When the electric coil (solenoid) is energized, it creates a magnetic force that pulls the armature into the coil. This caused the armature to push on the spool rod to move the spool of the valve.. The advantage of a solenoid lies within its less switching time.

Fig 4.8 Working of solenoid to shift spool of valveFigure 4.8 shows the working of a solenoid actuated valve when left coil is energized, its creates a magnetic force that pulls the armature into the coil. Since the armature is connected to spool rod its pushes the spool towards right. Similarly when right coil is energized spool is moved towards left. When both coil is de-energized the spool will come to the mid position by spring force Figure a shows a symbol for single solenoid used to actuate 2- position, 4 way valve and b) shows symbol for 2 solenoids actuating a 3- position valve, 4 way valve.

12

Fig 4.8 a) Symbol for Single solenoid-actuated, 2- Position,

4-way spring centered DCV

102

Fig 4.8b) Symbol for Solenoid actuated, 3- position,

4- way spring centered DCV

4. Hydraulic actuation: This type actuation is usually known as pilot- actuated valve. The hydraulic pressure may directly used on the end face of the spool. The pilot ports are located on the valve ends. Fig 4.9a shows a directional valve where the rate of shifting the spool from one side to another can be controlled by a needle valve. Fluid entering the pilot pressure port on the X end flows through the check valve and operates against the piston. This forces the spool to move towards the opposite position. Fluid in the Y end (right end ,not shown in the figure) is passed through the adjustable needle valve and exhausted back to tank. The amount of fluid bled through the needle valve controls how fast the valve will shift. Fig 4.9b shows the symbol of pilot actuated 2 / 4 DCV.

Fig 4.9a Pilot actuated DCV

B

Y P T

Fig 4.9b Symbol for pilot actuated 2 /4 DCV

5. Pneumatic actuation : Directional control valve can also be shifted by applying air pressure against a piston at either end of the valve spool. When air is introduced through the left end passage (X), its pressure pushes against the piston to shift the spool to the right. Removal of this left end air supply and introduction of air through the right end passage (Y) causes the spool to shift to the left. Figure 4.10 shows the symbol for pneumatic actuated 2 / 4 DCV. Note that the shaded arrow represents the pilot actuation as in fig 4.9 and the unshaded arrow represent pneumatic signal.

B

XY

T

Fig 4.10 Symbol for Pneumatic actuated 2 / 4 DCV

6. Indirect actuation of directional control valve : We have seen that a directional valve spool can be positioned from one extreme position to another by actuated it by manually, mechanically, electrically (solenoid), hydraulic (pilot) and pneumatic. The mode of actuation has no influence on the basic operation of these switching circuits. However since there is usually not a lot of force available, direct actuation is restricted to use with rather smaller valves. Especially with direct actuation, the greatest disadvantage is that the force which can be developed by them to shift a directional valve spool is limited. As a matter of fact, the force required to shift a directional spool is substantial in the larger size.

Larger valves are often indirectly actuated in one after the other sequence. First the smaller valve is directly actuated. Flow from the smaller valve is directed to either side of the larger valve when shifting is required. The main DCV is referred as pilot actuated DCV. The control oil can come from a separate circuit or from the same systems pressure line. Pressure for pilot valve operation is usually supplied internally from the pressure passage in the main valve. These two valves are often incorporated as a single unit. Therefore one may find it hard to see that it is an indirectly controlled valve. These valves are also called as Electro-hydraulic operated DCV.

4.2 PRESSURE CONTROL VALVE

These are the units ensuring the control of pressure. A throttling orifice is present in the valve and by variation of orifice, the pressure level can be controlled or at a particular pressure, a switching action can be influenced.

Different types of pressure control valves: Pressure control valves are usually named for their primary function such as relief valve, sequence valve, unloading valve, pressure reducing valve and counterbalance valve.

Pressure Relief valve:The pressure relief valves are used to protect the hydraulic components from excessive pressure. This is one of the most important components of a hydraulic system and is essentially required for safe operation of the system. Its primary function is to limit the system pressure within a specified range. It is normally a closed type and it opens when the pressure exceeds a specified maximum value by diverting pump flow back to the tank. The simplest type valve contains a poppet held in a seat against the spring force as shown in Figure 4.16 the fluid enters from the opposite side of the poppet. When the system pressure exceeds the preset value, the poppet lifts and the fluid is escaped through the orifice to the storage tank directly. It reduces the system pressure and as the pressure reduces to the set limit again the valve closes. This valve does not provide a flat cut-off pressure limit with flow rate because the spring must be deflected more when the flow rate is higher. Various types of pressure control valves are discussed in the following sections:

1. Direct type of relief valve

Figure 4.11 Pressure Relief Valve

Schematic of direct pressure relief valve is shown in figure 4.11 .This types of valves has two ports; one of which is connected to the pump and another is connected to the tank. It consists of a spring chamber where poppet is placed with a spring force. Generally, the spring is adjustable to set the maximum pressure limit of the system. The poppet is held in position by combined effect of spring force and dead weight of spool. As the pressure exceeds this combined force, the poppet raises and excess fluid bypassed to the reservoir (tank). The poppet again reseats as the pressure drops below the pre-set value. A drain is also provided in the control chamber. It sends the fluid collected due to small leakage to the tank and thereby prevents the failure of the valve.

2. Unloading Valve

Figure 4.12 Unloading Valve

The construction of unloading valve is shown in Figure 4.12 This valve consists of a control chamber with an adjustable spring which pushes the spool down. The valve has two ports: one is connected to the tank and another is connected to the pump. The valve is operated by movement of the spool. Normally, the valve is closed and the tank port is also closed. These valves are used to permit a pump to operate at the minimum load. It works on the same principle as direct control valve that the pump delivery is diverted to the tank when sufficient pilot pressure is applied to move the spool. The pilot pressure maintains a static pressure to hold the valve opened. The pilot pressure holds the valve until the pump delivery is needed in the system. As the pressure is needed in the Hydraulic circuit; the pilot pressure is relaxed and the spool moves down due to the self-weight and the spring force. Now, the flow is diverted to the hydraulic circuit. The drain is provided to remove the leaked oil collected in the control chamber to prevent the valve failure. The unloading valve reduces the heat buildup due to fluid discharge at a preset pressure value.

3. Sequence valve

Figure 4.13 Sequence valve

The primary function of this type of valve is to divert flow in a predetermined sequence. It is used to operate the cycle of a machine automatically. A sequence valve may be of direct-pilot or remote-pilot operated type.

Schematic of the sequence valve is shown in Figure 4.13 its construction is similar to the direct relief valve. It consists of the two ports; one main port connecting the main pressure line and another port (secondary port) is connected to the secondary circuit. The secondary port is usually closed by the spool. The pressure on the spool works against the spring force. When the pressure exceeds the preset value of the spring; the spool lifts and the fluid flows from the primary port to the secondary port. For remote operation; the passage used for the direct operation is closed and a separate pressure source for the spool operation is provided in the remote operation mode.

4. Counterbalance Valve

Figure 4.14 Counter Balance Valve

The schematic of counterbalance valve is shown in Figure 4.14. It is used to maintain the back pressure and to prevent a load from failing. The counterbalance valves can be used as breaking valves for decelerating heavy loads. These valves are used in vertical presses, lift trucks, loaders and other machine tools where position or hold suspended loads are important. Counterbalance valves work on the principle that the fluid is trapped under pressure until pilot pressure overcomes the pre-set value of spring force. Fluid is then allowed to escape, letting the load to descend under control. This valve is normally closed until it is acted upon by a remote pilot pressure source. Therefore, a lower spring force is sufficient. It leads to the valve operation at the lower pilot pressure and hence the power consumption reduces, pump life increases and the fluid temperature decreases.

5. Pressure Reducing Valve

Figure 4.15 Pressure Reducing Valve

Sometimes a part of the system may need a lower pressure. This can be made possible by using pressure reducing valve as shown in Figure 4.15. These valves are used to limit the outlet pressure. Generally, they are used for the operation of branch circuits where the pressure may vary from the main hydraulic pressure lines. These are open type valve and have a spring chamber with an adjustable spring, a movable spool as shown in figure 4.15. A drain is provided to return the leaked fluid in the spring (control) chamber. A free flow passage is provided from inlet port to the outlet port until a signal from the outlet port tends to throttle the passage through the valve. The pilot pressure opposes the spring force and when both are balanced, the downstream is controlled at the pressure setting. When the pressure in the reduced pressure line exceeds the valve setting, the spool moves to reduce the flow passage area by compressing the spring. It can be seen from the figure that if the spring force is more, the valve opens wider and if the controlled pressure has greater force, the valves moves towards the spring and throttles the flow.

4.3 Flow Control Valves Flow-control valves are used to control an actuators speed by metering flow. Metering is measuring or regulating the flow rate to or from an actuator. A water faucet is an example of a flow-control valve. Flow rate varies as a faucet handle is turned clockwise or counterclockwise. In a closed position, flow stops. Many flow-control valves used in fluid-powered systems are similar in design and operation to water faucets. In hydraulic circuits, flow-control valves are generally used to control the speed of hydraulic motors and work spindles and the travel rates of tool heads or slides. Flow-control valves incorporate an integral pressure compensator, which causes the flow rate to remain substantially uniform regardless of changes in workload. A no pressure, compensated flow control, such as a needle valve or fixed restriction, allows changes in the flow rate when pressure drop through it changes.Variations of the basic flow-control valves are the flow-control-and-check valves and the flow-control-and-overload relief valves. Models in the flow-control-and-check-valve series incorporate an integral check valve to allow reverse free flow. Models in the flow-control -and- overload-relief-valve series incorporate an integral relief valve to limit system pressure. Some of these valves are gasket-mounted, and some are panel-mounted.

1 Gate ValveIn this type of valve, a wedge or gate controls the flow. To open and close a passage, a handwheel moves a wedge or gate up and down across a flow line. Figure 4.16, shows the principal elements of a gate valve. Area A shows the line connection and the outside structure of the valve; area B shows the wedge or gate inside the valve and the stem to which the gate and the handwheel are attached. When the valve is opened, the gate stands up inside the bonnet with its bottom flush with the wall of the line. When the valve is closed, the gate blocks the flow by standing straight across the line where it rests firmly against the two seats that extend completely around the line.A gate valve allows a straight flow and offers little or no resistance to the fluid flow when the valve is completely open. Sometimes a gate valve is in the partially open position to restrict the flow rate. However, its main use is in the fully open or fully closed positions. If the valve is left partly open, the Valve's face stands in the fluid flow, which will act on the face and cause it to erode

Fig. 4.16 Gate valve

2. Plug or glove valve

Fig. 4.17 Plug or glove valve

The plug valve is quite commonly used valve. It is also termed as glove valve. Schematic of plug or glove valve is shown in Figure. This valve has a plug which can be adjusted in vertical direction by setting flow adjustment screw. The adjustment of plug alters the orifice size between plug and valve seat. Thus the adjustment of plug controls the fluid flow in the pipeline. The characteristics of these valves can be accurately predetermined by machining the taper of the plug. The typical example of plug valve is stopcock that is used in laboratory glassware. The valve body is made of glass or Teflon. The plug can be made of plastic or glass. Special glass stopcocks are made for vacuum applications. Stopcock grease is used in high vacuum applications to make the stopcock air-tight.

3. Butterfly valve

A butterfly valve is shown in Figure. It consists of a disc which can rotate inside the pipe. The angle of disc determines the restriction. Butterfly valve can be made to any size and is widely used to control the flow of gas. These valves have many types which have for different pressure ranges and applications. The resilient butterfly valve uses the flexibility of rubber and has the lowest pressure rating. The high performance butterfly valves have a slight offset in the way the disc is positioned. It increases its sealing ability and decreases the wear. For high-pressure systems, the triple offset butterfly valve is suitable which makes use of a metal seat and is therefore able to withstand high pressure. It has higher risk of leakage on the shut-off position and suffers from the dynamic torque effect. Butterfly valves are favored because of their lower cost and lighter weight. The disc is always present in the flow therefore a pressure drop is induced regardless of the valve position.

Fig. 4.18 Butterfly valve

4. Ball Valve

The ball valve is shown in Figure 4.19. This type of flow control valve uses a ball rotated inside a machined seat. The ball has a through hole as shown in Figure. It has very less leakage in its shut -off condition. These valves are durable and usually work perfectly for many years. They are excellent choice for shutoff applications. They do not offer fine control which may be necessary in throttling applications. These valves are widely used in industries because of their versatility, high supporting pressures (up to 1000 bar) and temperatures (up to 250C). They are easy to repair and operate.

Fig 4.19 Ball valve

5. Balanced valve

Schematic of a balanced valve is shown in figure 4.20. It comprises of two plugs and two seats. The opposite flow gives little dynamic reaction onto the actuator shaft. It results in the negligible dynamic torque effect. However, the leakage is more in these kind of valves because the manufacturing tolerance can cause one plug to seat before the other. The pressure-balanced valves are used in the houses. They provide water at nearly constant temperature to a shower or bathtub despite of pressure fluctuations in either the hot or cold supply lines.

Figure 4.20 Balanced valves

5) Actuators:-

A hydraulic actuator receives pressure energy and converts it to mechanical force and motion. An actuator can be linear or rotary. A linear actuator gives force and motion outputs in a straight line. It is more commonly called a cylinder but is also referred to as a ram, reciprocating motor, or linear motor. A rotary actuator produces torque and rotating motion. It is more commonly called a hydraulic motor or motor.

5.1 Cylinders A cylinder is a hydraulic actuator that is constructed of a piston or plunger that operates in a cylindrical housing by the action of liquid under pressure. Figure shows the basic parts of a cylinder. Cylinder housing is a tube in which a plunger (piston) operates. In a ram-type cylinder, a ram actuates a load directly. In a piston cylinder, a piston rod is connected to a piston to actuate a load. An end of a cylinder from which a rod or plunger protrudes is a rod end. The opposite end is a head end. The hydraulic connections are a head-end port and a rod-end port (fluid supply).

a. Single-Acting Cylinder. This cylinder only has a head-end port and is operated hydraulically in one direction. When oil is pumped into a port, it pushes on a plunger, thus extending it. To return or retract a cylinder, oil must be released to a reservoir. A plunger returns either because of the weight of a load or from some mechanical force such as a spring. In mobile equipment, flow to and from a single-acting cylinder is controlled by a reversing directional valve of a single-acting type.

b. Double-Acting Cylinder. This cylinder must have ports at the head and rod ends. Pumping oil intothe head end moves a piston to extend a rod while any oil in the rod end is pushed out and returned to a reservoir. To retract a rod, flow is reversed. Oil from a pump goes into a rod end, and a head-end port is connected to allow return flow. The flow direction to and from a double-acting cylinder can be controlled by a double-acting directional valve or by actuating a controlof a reversible pump.

c. Differential Cylinder. In a differential cylinder, the areas where pressure is applied on a piston are not equal. On a head end, a full piston area is available for applying pressure. At a rod end, only an annular area is available for applying pressure. A rods area is not a factor, and what space it does take up reduces the volume of oil it will hold. Two general rules about a differential cylinder are that. With an equal GPM delivery to either end, a cylinder will move faster when retracting because of a reduced volume capacity.With equal pressure at either end, a cylinder can exert more force when extending because of the greater piston area. In fact, if equal pressure is applied to both ports at the same time, a cylinder will extend because of a higher resulting force on a head end.

d. Piston-Type Cylinder. In his cylinder, a cross-sectional area of a piston head is referred to as a piston-type cylinder. A piston-type cylinder is used mainly when the push and pull functions are needed.A single-acting, piston-type cylinder uses fluid pressure to apply force in one direction. In some designs, the force of gravity moves a piston in the opposite direction. However, most cylinders of this type apply force in both directions. Fluid pressure provides force in one direction and spring tension provides force in the opposite direction.

Fig 5.1 Piston Type cylinderFigure shows a single-acting, spring-loaded, piston-type cylinder. In this cylinder, a spring is located on the rod side of a piston. In some spring-loaded cylinders, a spring is located on a blank side, and a fluid port is on a rod end of a cylinder.Most piston-type cylinders are double-acting, which means that fluid under pressure can be applied to either side of a piston to provide movement and apply force in a corresponding direction. Figure shows a double-acting piston-type cylinder this cylinder contains one piston and piston-rod assembly and operates from fluid flow in either direction. The two fluid ports, one near each end of a cylinder, alternate as an inlet and an outlet, depending on the directional-control valve flow direction. This is an unbalanced cylinder, which means that there is a difference in the effective working area on the two sides of a piston. A cylinder is normally installed so that the head end of a piston carries the greater load; that is, a cylinder carries the greater load during a piston-rod extension stroke.Figure shows a balanced, double-acting, piston-type cylinder. The effective working area on both sides of a piston is the same, and it exerts the same force in both directions.

5.2. Double-acting, piston-type cylinder

e. Cushioned Cylinder. To slow an action and prevent shock at the end of a piston stroke, some actuating cylinders are constructed with a cushioning device at either or both ends of a cylinder. This cushion ids usually a metering device built into a cylinder to restrict the flow at an outlet port, thereby slowing down the motion of a piston .Figure shows a cushioned actuating cylinder

Fig 5.3 Cushioned, actuating cylinder

f. Lockout Cylinders. A lockout cylinder is used to lock a suspension mechanism of a tracked vehicle when a vehicle functions as a stable platform. A cylinder also serves as a shock absorber when a vehicle is moving. Each lockout cylinder is connected to a road arm by a control lever. When each road wheel moves up, a control lever forces the respective cylinder to compass..

Hydraulic fluid is forced around a piston head through restrictor ports causing a cylinder to act as a shock absorber. When hydraulic pressure is applied to an inlet port on each cylinders connecting eye, an inner control-valve piston is forced against a spring in each cylinder. This action closes the restrictor ports, blocks the main pistons motion in each cylinder, and locks the suspension system

5.2 Hydraulic Motors

Hydraulic motors convert hydraulic energy into mechanical energy. In industrial hydraulic circuits, pumps and motors are normally combined with a proper valving and piping to form a hydraulic-powered transmission. A pump, which is mechanically linked to a prime mover, draws fluid from a reservoir and forces it to a motor. A motor, which is mechanically linked to the workload, is actuated by this flow so that motion or torque, or both, are conveyed to the work. Figure 4-9 shows the basic operations of a hydraulic motor.

Figure 5.4 Basic operations of a hydraulic motor

The principal ratings of a motor are torque, pressure, and displacement. Torque and pressure ratings indicate how much load a motor can handle. Displacement indicates how much flow is required for a specified drive speed and is expressed in cubic inches per revolutions, the same as pump displacement. Displacement is the amount of oil that must be pumped into a motor to turn it one revolution. Most motors are fixed-displacement; however, variable-displacement piston motors are in use, mainly in hydrostatic drives. The main types of motors are gear, vane, and piston. They can be unidirectional or reversible. (Most motors designed for mobile equipment are reversible.)

Fig 5.5 Gear-type motor

a. Gear-Type Motors. Figure shows a gear-type motor. Both gears are driven gears, but only one is connected to the output shaft. Operation is essentially the reverse of that of a gear pump. Flow from the pump enters chamber A and flows in either direction around the inside surface of the casing, forcing the gears to rotate as indicated. This rotary motion is then available for work at the output shaft.

Fig 5.6 Vane-type motorb. Vane-Type Motors. Figure shows a vane-type motor. Flow from the pump enters the inlet, forces the rotor and vanes to rotate, and passes out through the outlet. Motor rotation causes the output shaft to rotate. Since no centrifugal force exists until the motor begins to rotate, something, usually springs, must be used to initially hold the vanes against the casing contour. However, springs usually are not necessary in vane-type pumps because a drive shaft initially supplies centrifugal force to ensure vane-to-casing contact.

Fig 5.7 Pressure differential on a vane-type motor

Vane motors are balanced hydraulically to prevent a rotor from side-loading a shaft. A shaft is supported by two ball bearings. Torque is developed by a pressure difference as oil from a pump is forced through a motor. Figure shows pres-sure differential on a single vane as it passes the inlet port. On the trailing side open to the inlet port, the vane is subject to full system pressure. The chamber leading the vane is subject to the much lower outlet pressure. The difference in pressure exerts the force on the vane that is, in effect, tangential to the rotor. This pressure difference is effective across vanes 3 and 9 as shown in Figure. The other vanes are subject to essentially equal force on both sides. Each will develop torque as the rotor turns. Figure shows the flow condition for counterclockwise rotation as viewed from the cover end. The body port is the inlet, and the cover port is the outlet. Reverse the flow, and the rotation becomes clockwise.In a vane-type pump, the vanes are pushed out against a cam ring by centrifugal force when a pump is started up. A design motor uses steel-wire rocker arms to push the vanes against the cam ring. The arms pivot on pins attached to the rotor. The ends of each arm support two vanes that are 90 degrees apart. When the cam ring pushes vane A into its slot, vane B slides out. The reverse also happens. A motors pressure plate functions the same as a pump's. It seals the side of a rotor and ring against internal leakage, and it feeds system pressure under the vanes to hold them out against a ring. This is a simple operation in a pump because a pres-sure plate is right by a high-pressure port in the cover.

Fig 5.8 Rocker arms pushing vanes in a pump

6) Fittings and Connectors

Fittings are used to connect the units of a fluid-powered system, including the individual sections of a circulatory system. Many different types of connectors are available for fluid-powered systems. The type that you will use will depend on the type of circulatory system (pipe, tubing, or flexible hose), the fluid medium, and the maximum operating pressure of a system. Some of the most common types of connectors are described below:

a. Threaded Connectors. Threaded connectors are used in some low-pressure liquid-powered systems. They are usually made of steel, copper, or brass, in a variety of designs. The connectors are made with standard female threading cut on the inside surface. The end of the pipe is threaded with outside (male) threads for connecting.

Fig 6.1 Threaded-pipe connectors

Standard pipe threads are tapered slightly to ensure tight connections.

To prevent seizing (threads sticking) apply a pipe-thread compound to the threads. Keep the two end threads free of the compound so that it will not contaminate the fluid. Pipe compound, when improperly applied, may get inside the lines and harm the pumps and the control equipment.

b. Flared Connectors. The common connectors used in circulatory systems consist of tube lines. These connectors provide safe, strong, dependable connections without having to thread, weld, or solder the tubing. A connector consists of a fitting, a sleeve, and a nut

Fig. 6.2 Flared tube connector

Fittings are made of steel, aluminum alloy, or bronze. The fittings should be of a material that is similar to that of a sleeve, nut, and tubing. Fittings are made in unions, 45- and 90-degree elbows, Ts, and various other shapes. Figure shows some of the most common fittings used with flared connectors.

Fittings are available in many different thread combinations. Unions have tube connections on each end; elbows have tube connections on one end and a male pipe thread, female pipe thread, or a tube connection on the opposite end; crosses and Ts have several different combinations.Tubing used with flared connectors must be flared before being assembled. A nut fits over a sleeve and, when tightened, draws the sleeve and tubing flare tightly against a male fitting to form a seal. A male fitting has a cone-shaped surface with the same angle as the inside of a flare. A sleeve supports the tube so that vibration does not concentrate at the edge of a flare but that it does distribute the shearing action over a wider area for added strength. Tighten the tubing nuts with a torque wrench to the value specified in applicable regulations.

If an aluminum alloy flared connector leaks after tightening to the specified torque, do not tighten it further. Disassemble the leaking connector and correct the fault. If a steel connector leaks, you may tighten it 1/6 turn beyond the specified torque in an attempt to stop the leak. If you are unsuccessful, disassemble it and repair it.

Flared connectors will leak if

A flare is distorted into the nut threads. A sleeve is cracked. A flare is cracked or split. A flare is out-of-round. A flare is eccentric to the tubes OD. A flare's inside is rough or scratched. A fitting cone is rough or scratched. The threads of a fitting or nut are dirty, damaged, or broken.

Fig 6.3 Flared-tube fittings

c. Flexible-Hose Couplings. If hose assembly is fabricated with d attachable couplings (Figure ), use the same couplings when reacting the replacement assembly, as long as the failure (leak) did not occur at a coupling. Failure occurred at a coupling, card it.

Fig 6.4 Field-attachable couplings

When measuring a replacement hose assembly for screw on a pings measure from the edge a retaining bolt. Hose in hose blocks and n in a bench vice for effective cutting, a blade should have 24 or 32 teeth per inch. To remove an old coupling on a hose assembly that is fabricated with permanently attached couplings, you just discard the entire assembly.

d. Reusable Fittings. To use a skived fitting you must strip (skive) the hose to a length equal to that from a notch on a fitting to the end of the fitting. (A notch on a female portion of a fitting in Figure indicates it to be a skived fitting.) To assemble a conductor using skived fittings

Fig. 6.5 permanently attached couplings

Determine the length of the skive.

Make a cut around the hose with a sharp knife. Make sure that you cut completely through the rubber cover of the hose.

Cut lengthwise to the end of the hose. Lift the hose flap and remove it with pliers.

Repeat the process on the opposite end of the hose.

Place the female portion of the fitting in a bench vice and secure it in place.

Lubricate the skived portion of the hose with hose lubricant (hydraulic fluid or engine oil, if necessary).

Insert the hose into the female socket and turn the hose counterclockwise until it bottoms on the shoulder of the female socket, then back off 1/4 turn.

Place the female socket in an upright position (Figure 6.5) and insert the male nipple into the female socket.

Turn the male nipple clockwise (Figure 6.5) until the hex is within 1/32 inch of the female socket.

Repeat the above process on the opposite end of the hose.

7) CUTTING PROCEDURE

1. Hydraulic Vane Pump:-1) First of all the vane pump oil is drained.2) After washing the marking is done3) Then the cut the cover on the marking part with the help of hacksaw.4) After then we cuts the spring assembly in pump & also the body by using hand grinder.5) The grinder is used to finish the rough cutting surface. In small area finishing the files are used.6) After the finishing clean & paints with the color to inner & outer side & also paint & dry in the air.7) After this process all the removed part assemble it.8) Then we paint the parts with various shades of color.

Fig. 7.1 Cutting & grinding of vane pump

2. Gear Pump:-1) First of all the Gear pump oil is drained.2) The gear pump cover is open, it clean with cotton, & kerosene. Then foam water is used to washing.3) After washing the marking is done on the gear pump.4) Then the cut the cover of marking point with the help of hacksaw.5) Then we cut the body of pump by using hand grinder.6) The grinder is used to finish the rough cutting surface in small area & for finishing the file is used.7) After finishing it clean & paints with the color & to inner & outer side.8) After this process both the gears are assemble in casing.

Fig. 7.2 Dismantling & cutting of gear pump

3. Double Acting Cylinder:-1) First cleaning the double acting cylinder in outside.2) Then we remove connector from cylinder, bolt or stud & dismantle all part of cylinder like piston, piston rod, oil seal etc.3) Then we again clean the all part with kerosene.4) Then we cut cylinder block by using grinder.5) After cutting us removes the sharp edges by using file.6) Then we paint it.

4. Single Acting Cylinder:-1) First cleaning the single acting cylinder in outside then we remove connector from cylinder, bolt or stud & dismantle all part of cylinder like piston, piston rod, oil seal etc.2) Then we again clean the all part with kerosene.3) Then we cut the cylinder block by using hacksaw & grinder.4) Then we paint with red color on cutting edge.5) After drying the color we assemble the all parts & then mount on a board with the help of clamps.

5. Flow Control Valve:-1) First cleaning the flow control valve in outside.2) After cleaning the throttle position & diverting position by kerosene.3) Marking is done on flow control valve.4) Then cut the flow control valve block by using grinder.

Fig. 7.3 cutting of flow control valve6. Hoses:-1) Firstly clean the hoses outside by using cloth.2) Then we cut the hoses by using of hacksaw.3) Then paint it with red color.

8) TOOLS AND EQUIPMENTGrinders and Grinding Machines Information:-Grinders and grinding machines use an abrasive that is bonded to a wheel, belt or disc to remove material and improve surface finish. Dev ices can be pneumatically driven or powered by a combustion engine or electric motor.Grinders and grinding machines can use single phase or three phase power and are available in a range of voltages 60 Hz power is used in North America. 50 Hz power is used internationally.Features:- Optional features include Cabinets and enclosures Double sided disks Dressing systems Dust collection or filtration systems

Related Products & Services:-Honing, Lapping, and super finishing MachinesHoning, lapping and super finishing equipment are used to improve surface finish or geometry to tight tolerances.

Hacksaw:-A hacksaw is a fine tooth hand saw with a blade held under tension in a frame, used for cutting materials such as metal or plastics. Hand held hacksaws consist of a metal arch with a handle, usually a pistol grip, with pins for attaching a narrow disposable blade. A screw or other mechanism is used to put the thin blade under tension. Te blade can be mounted with the teeth facing toward or away from the handle, resulting in cutting action on either the push or pull stroke. On the push stroke, the arch will flex slightly, decreasing the tension on the blade, often resulting in an increased tendency of the blade to buckles and crack. Cutting on the pull stroke increases the blade tension and will result in greater control for the cut and longer blade life.Blades: -Blades are available in standardized lengths, usually 10 or 12 inches for a standard hand hacksaw. Junior hacksaws are half this size. Powered hacksaws may use large blades in a range of sizes, or small machines may use the same hand blades.Electric hacksaw:-A power hacksaw (or electric hacksaw) is a type of hacksaw that is powered either by its own electric motor or connected to a stationary engine. Most power hacksaws are stationary machines but some portable models do exist. Stationary models usually have a mechanism to lift up the saw blade on the return stroke and some have a coolant pump to prevent the saw blade from overheating.

9) CostingSr. no.ObjectAmount

1Gear Pump2,500

2Vane Pump3,500

3Single Acting cylinder1,500

4Double Acting cylinder3,000

5Flow control valve950

6Direction Control Valve3,000

7Connectors600

8Hoses600

9Coupler900

10Boards850

11Nut &bolt60

12Fabrication600

13Color500

14Painting500

15Kolhapur visit1,000

16Traveling200

Total20,150

10) CONCLUSIONThe main purpose of our project is to collect all information about hydraulic devices. In this project we show all internal parts of gear pump and vane pump, as well as try to show Direction control valve, flow control valve, single and double acting cylinder, Hose pipes. With its mechanism in board mounted condition.& its works properly.This project is good collection of Gear pump, vane pump and other parts. We try to develop our automobile lab, hence we select this project.

11) Reference1. Chapter2_Hydraulics_control_in_machine_tools nptel.2. Hydraulic Pumps pumpschool.com3. en.wikipedia.org/wiki/Hydraulic pump4. Field Manual, No. 5-499, Headquarters, Department of the Army.5. BASIC HYDRAULIC SYSTEMS AND COMPONENTS, Sub course Number AL 0926, EDITION A,US Army Aviation Logistics School Fort Eustis, Virginia 23604-54394, Credit Hours, Edition Date: September 19946. Collage library.7. McNeil, Ian (1990).An Encyclopedia of the History of Technology. London: Rout ledge. p.961.ISBN0-415-14792-1.8. Jump upHousel, David A.(1984),From the American System to Mass Production, 1800-1932: The Development of Manufacturing Technology in the United States, Baltimore, Maryland: Johns Hopkins University Press,ISBN978-0-8018-2975-8,LCCN830162699. Jump up to: Hunter, Louis C.; Bryant, Lynwood (1991).A History of Industrial Power in the United States, 1730-1930, Vol. 3: The Transmission of Power. Cambridge, Massachusetts, London: MIT Press.ISBN0-262-08198-9.