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MAGICAL USE OF PNEUMA IN INDUSRIAL AUTOMATION Maharshi Trivedi 5 th semester MH 074, Faculty Of Technology, Dharmsinh Desai University, Nadiad

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Content Fluid Power System Brief History of PNEUMATICS Use and Advantages of PNEUMATICS System Basic Parts of any PNEUMATIC Circuits Air Generation and Distribution Air service Unit Filter Air Presser regulator Lubricator Flow Control Valve D.C. Valve Actuators Energy Conversion Cycle Some PNEUMATIC Circuits

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Fluid Power System Fluid power systems are used in most of the modern machineries in order to achieve the success in POWER TRANSMISSION, because sometimes the mechanical drives are bulky and complicated. Fluid power system is the properly pressurized flow of air or liquid which is used to actuate the mechanical means which is further used to achieve the work. Thus, the fluid power energy is broadly classified as, 1) Fluid power energy with air medium 2) Fluid power energy with liquid medium So, Compressed air as the working medium = PNEUMATICS Liquid as the working medium = HYDRAULICS

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Brief History of PNEUMATICS The first man whom, we know with certainly to have engaged himself with pneumatics i.e. the use of compressed air as the working medium was the Greek KTESIBIOS, he built a compressed air impulse catapult(Shown in the fig is mechanical catapult). The term PNEUMA is described as the ambient Greek and meant breath or heavy wind and also the soul in philosophy. PNEUMATICS is derived from the word PNEUMA. The use of it is preferred when the need of automation and rationality of optional sequences continued to increase.

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Use and Advantages of PNEUMATICS System USE: For pneumatic tools for automation of m/c tools (ex. CNC LATHE). In mining industries and refineries and also in aviation field. In automation of food processing and in chemical material handling. In plastic manufacturing industries. For building up the specific atmosphere condition in textile industries. In spray painting. ADVANTAGES: There will be no spark hazards in an explosive atmosphere, as it is having the air as the working medium and the temperature conductance of air is less then the liquid. Air is readily available and compressed air can be stored in a tank for instant use and a small compressor can be used to fill the air for intermittent use.

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Basic Parts of any PNEUMATIC Circuits Air Compressor Service Unit: F-R-L: Filter Pressure Regulator Lubricator Air distributor or Junction box Valves Cylinders

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Air generation and distribution The main function of the air generation and distribution system is to supply the clean, dry air at the required pressure. Compressors are the air generation units.(Classification of compressors are shown in the fig.) Compressors compress the air and supply it to the distribution system in the factory and also it air service unit(FRL unit) prepares the air and delivers to the control unit. (Compressors are not much discussed in this ppt, the diff. types are used as per the requirement)

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Air Service Unit (FRL Unit) The air service unit is a combination of: 1.Compressed air filter(With water separator) 2.Compressed air regulator 3.Compressed air lubricator The main function of the service unit is to provide the pneumatic system with a well cleaned, lubricated and regulated compressed air. The three units Filter-Regulator- Lubricator together are termed as FRL Unit or Service Unit.

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Cont. They are commonly fitted to each and every pneumatic work station. After it is determined whether fog-or-mist-type lubrication is best suited for the application, lubricators are selected according to piping size. Air Filter: Air filters are used in a pneumatic system to perform the following main functions: To prevent entrance of solid contaminants to the system. To condense and remove the water vapour that is present in the air passing through it, in short it makes the air dry and clean. To arrest any submicron particles that may pose a problem in the system components.

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Construction of Air Filter The main component of the filter is the filter cartridge, is made of bronze or brass. This helps to provide a random zig-zag passage for the air to flow which in turn, will arrest the solid particles. The water vapour gets condensed inside the filter and collects at the bottom of the filter bowl. At the bottom of the filter bowl there is an on-off drain valve which could be manually opened to drain off the accumulated water and other solid particles.(Construction is shown in fig.)

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Oil free Filter Element If absolutely oil and moisture free air is required, coalescent type(To form whole as a unit means removal of oil and moisture) of filter may be used. The filter medium is made of metal- wools which is kept compressed inside a stainless steel shell and the outer shell is made of some porous material, e.g. ceramic or borosilicate which can absorb the finer oil- molecules. The filtration medium is housed on a seat made of stainless steel.

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Air Pressure Regulator The main function of pressure regulator valve is to regulate the in coming pressure to the system so that desired air pressure is capable of flowing at a steady condition. The pressure regulation is achieved by opening the poppet valve. This is done by adjustable screw. It will move the diaphragm. The pressure of the flowing air will be directly proportional to the compression of the spring underneath the diaphragm.

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Lubricator In most of the system the air is first filtered, then regulated to the specific pressure and made pass through the lubricator in order to form mist of oil and air to providing lubrication of the mating components of the valve. Lubricator unit follow the principle of venturimeter. According to the law, as soon as compressed air flows into the throttled zone of the pipe, a pressure differential sets in. Due to this, the oil is pushed up to the pipe when air is fed to the oil reservoir through the pipe.

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Diagram of construction of Lubricator with symbol

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Flow Control Valves Flow control valves are used in circuits to control the flow rate of the compressed air from one part of the circuit to another. They regulate the amount of the compressed air passing through a valve by means of a metering orifice. Examples are throttle valve and one-way flow control valve.

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Throttle Valve(Restriction or needle valve) Throttle valve is used to control the speed of pneumatic cylinders in both direction of motion. So if the symbol is not mentioned on the valve by manufacturer, then also it can be connected in both the direction due to its geometry. It consists of an orifice whose cross- section can be controlled by an externally adjustable needle.

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One way Flow Control Valve (Throttle relief Valve or Throttle check Valve) A one way flow control valve is used to control the flow of pneumatic cylinders in one direction of motion only. The valve is a parallel arrangement of a throttle valve and a check valve. The check valve blocks the flow of air in one direction forcing the air to flow through the controlled cross-section. In opposite direction the air flows freely through the opened check valve. (Figure for this valve is shown in the next slide.)

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Why it is one way Flow Control Valve???

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Direction Control Valves

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D.C. Valves Direction control valves are used to direct the flow of the pressurize fluid in the desired directions. The main functions of these valves are to: Start Stop Regulate the direction of air flow They can be actuated to assume different positions by various actuating mediums. This results in corresponding connection or disruption of flow between various port openings. The openings are termed ways or ports. The ways are designated by letters: P=Compressor line port R=Exhaust port | A and B=Working ports to cylinders or motors

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Symbolic representation of D.C. Valves To represent valves in circuit diagram, symbols are used. Each position in the symbol is denoted by squares. Two positions are represented by two adjacent squares.

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How to Understand the Symbols in the circuits??? A valve position is represented by a square. Number of squares is equals to the no. of distinct positions that the valve can take up. Inside a square, the lines indicate the flow and the arrows, the direction of flow. Cut-offs of air flow are shown by short traverse lines inside the square. Connections to inlet and outlet ports are drawn only to a connecting position, i.e. neutral or initial position.

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Types of D.C. Valves Poppet valves (or seat valves) In a poppet valve, a simple valve seat is used in conjunction with a movable disc or ball to open or close internal air passages. A poppet valve quickly opens up a relatively large orifice in a short travel to permit the full flow of air. Slide valves (or spool valves) In a slide valve, a spool moves axially within the valve body to control the direction of flow. A slide vane is especially used as a final control element to handle the power signal to an actuating device because it is easy to shift the spool to perform the required switching function.

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Working diagram of poppet and slide valve Poppet valves (or seat valves) Slide valves (or spool valves)

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2/2 and 3/2 Way D.C. Valve(Normally Closed)

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Check Valves A check valve permits the air flow in one direction but stops it completely in the opposite direction. It basically consists of a valve body, movable ball or plate, it is biased by a spring force. As soon as the pressure applied by the compressed air becomes greater then the spring force, it allows the air to flow.

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Actuators Actuators are used for mechanical work which is developed by the power of compressed air: It is further classified as: Linear actuators Single acting cylinders Double acting cylinders Rotary actuators

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Energy Conversion Cycle

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Actual Valve Body 3/2 D.C. Valve (FESTO company)D.C. Valve(Actuation by push button )

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Some Pneumatics Circuits

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Working Circuit Video (Triggering D/A Cylinder with Limit Switch)

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PNEUMATIC Circuit in MATLAB!!!

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My Experiment of Hydraulic circuits with MATLAB!!!

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Thank You!!!