Valves Used in Fire Protection System

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TABLE OF CONTENTSAIR VENT VALVE

BALL VALVE

BUTTERFLY VALVE

CHECK VALVE

DRAIN VALVE

GATE VALVE

LANDING VALVES

WET ALARM VALVE

Y STRAINER

Air Vent ValveWhen liquid is pumped through the system, the initial air inside the piping is pushed into the air vent by the pressure of the flow. The float stays at its lower position and the

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valve is fully open, allowing the air that enters the air vent to be pushed around the float and discharged.

After the initial air venting, the liquid flows into the air vent. The float rises with the rising liquid level and closes the valve.

If air enters the air vent while it is closed, the liquid level drops and the float lowers to open the valve and discharge the air. When liquid flows into the air vent again, the float will rise to close the valve.

Ball valveA ball valve is a valve with a spherical disc, the part of the valve which controls the flow through it.

The sphere has a hole, or port, through the middle so that when the port is in line with both ends of

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the valve, flow will occur. When the valve is closed, the hole is perpendicular to the ends of the

valve, and flow is blocked. The handle or lever will be inline with the port position letting you "see"

the valve's position. The ball valve, along with the butterfly valve and plug valve, are part of the

family of quarter turn valves.

Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They

are therefore an excellent choice for shutoff applications (and are often preferred to globe

valves and gate valves for this purpose). They do not offer the fine control that may be necessary in

throttling applications but are sometimes used for this purpose.

Ball valves are used extensively in industrial applications because they are very versatile,

supporting pressures up to 1000 bar and temperatures up to 752°F (500°C) depending on the ball

valve design and material. Sizes typically range from 0.2 to 48 inches (0.5 cm to 121 cm). They are

easy to repair and operate.

The body of ball valves may be made of metal, plastic, or metal with a ceramic center. The ball is

often chrome plated to make it more durable.

Butterfly valveA butterfly valve is a valve which can be used for isolating or regulating flow. The closing

mechanism takes the form of a disk. Operation is similar to that of a ball valve, which allows for quick

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shut off. Butterfly valves are generally favored because they are lower in cost to other valve designs

as well as being lighter in weight, meaning less support is required. The disc is positioned in the

center of the pipe, passing through the disc is a rod connected to an actuator on the outside of the

valve. Rotating the actuator turns the disc either parallel or perpendicular to the flow. Unlike a ball

valve, the disc is always present within the flow, therefore a pressure drop is always induced in the

flow, regardless of valve position.

A butterfly valve is from a family of valves called quarter-turn valves. In operation, the valve is fully

open or closed when the disc is rotated a quarter turn. The "butterfly" is a metal disc mounted on a

rod. When the valve is closed, the disc is turned so that it completely blocks off the passageway.

When the valve is fully open, the disc is rotated a quarter turn so that it allows an almost unrestricted

passage of the fluid. The valve may also be opened incrementally tothrottle flow.

There are different kinds of butterfly valves, each adapted for different pressures and different

usage. The resilient butterfly valve, which uses the flexibility of rubber, has the lowest pressure

rating. The high performance butterfly valve, used in slightly higher-pressure systems, features a

slight offset in the way the disc is positioned, which increases the valve's sealing ability and

decreases its tendency to wear. The valve best suited for high-pressure systems is the triple offset

butterfly valve, which makes use of a metal seat,[clarification needed] and is therefore able to withstand a

greater amount of pressure.

Check valveA check valve, clack valve, non-return valve or one-way valve is a valve that normally

allows fluid (liquid or gas) to flow through it in only one direction.

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Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter

and the other for fluid to leave. There are various types of check valves used in a wide variety of

applications. Check valves are often part of common household items. Although they are available in

a wide range of sizes and costs, check valves generally are very small, simple, or inexpensive.

Check valves work automatically and most are not controlled by a person or any external control;

accordingly, most do not have any valve handle or stem. The bodies (external shells) of most check

valves are made of plastic or metal.

An important concept in check valves is the cracking pressure which is the minimum upstream

pressure at which the valve will operate. Typically the check valve is designed for and can therefore

be specified for a specific cracking pressure.

Drain valve

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The drain valve is opened to ensure any residual water is drained from the sprinkler zone for test or maintenance purpose.

Foot Valve

The foot valve prevents water from flowing backwards out of the jet pump and well piping back into the well when the jet pump stops operating.

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A foot valve is basically a check valve combined with an inlet strainer. The strainer prevents picking up large debris that could clog or jam the foot valve in its open position (or that might damage the water pump itself).

The check valve is a one-way valve that lets water flow up from the well and into the well piping. The spring loaded check valve closes when the well pump stops pumping.

Closing the check valve prevents water in the well piping from falling backwards into the well when the pump has stopped running. We need this function to keep the well piping and water pump filled with water - otherwise the well pump may lose prime, leading to loss of water in the building.

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Various types of valves are required to maintain optimum function of

water and air pumps, and among these valves are foot valves. Foot

valves are used to prime up a centrifugal pump; they are known for

their efficacy and affordability.

Description

Foot valves are a type of check valve and are placed at the pump’s wet well.

Unlike other valves, a foot valve is created with a larger flow area than the

actual pipe size to make sure that there is less head loss. Foot valves are

either made of PVC plastic or stainless steel, and they are known for keeping

the continuous presence of suction within the pump.

Function

Foot valves are used to maintain hydraulic pressure to keep the water flow in

accordance with the given settings or configurations. There are instances

where the pressure can actually pop the valve out and cause major leakage;

thus, it is important to use the right kind of material in the tubing to be able

to support the force within the valve.

Features

Being an important part of a centrifugal pump, foot valves come with easily

manageable features. Most foot valves are designed with a self-tapping male

and female threads to ensure easy installation; internal balls for quick

sealing and valve reaction; and flexibility to fit various types of water pump

uses, such as well development and volatile organic compounds sampling

and purging. Although they are cheaper to use, as compared to other valves

used to prime a pump, foot valves are usually made up of heavy duty cast

iron and bronze, as well as PVC (depending on the type) so that they will last

longer while submerged in the water.

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Types

There are three types of foot valves. The micro-flow system valves are used

in direct push technology micro wells and multi-level well installations. These

are usually made of stainless steel and are either of fluorotherm (FEP) or

high-density polyethylene (HDPE) tubing. The high-flow system valve is used

on 2-inch wells or larger and can stand high pumping rates and very deep

wells. On the other hand, low-flow system valves are used in small diameter

piezometers, which lift up to 100 feet of water.

Support

Foot valves usually come with surge blocks. A surge block is a tool used to

press the body of a valve to remove the residues that may block smooth flow

of water within the pump during operation. It also helps the valve expand

while being used, thus enabling the presence of increased pressure without

causing damage to the valve itself.

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Gate valveA gate valve, also known as a sluice valve, is a valve that opens by lifting a round or rectangular

gate/wedge out of the path of the fluid. The distinct feature of a gate valve is the sealing surfaces

between the gate and seats are planar, so gate valves are often used when a straight-line flow of

fluid and minimum restriction is desired. The gate faces can form a wedge shape or they can be

parallel. Gate valves are primarily used to permit or prevent the flow of liquids, but typical gate

valves shouldn't be used for regulating flow, unless they are specifically designed for that purpose.

Because of their ability to cut through liquids, gate valves are often used in the petroleum industry.

For extremely thick fluids, a specialty valve often known as a knife valve is used to cut through the

liquid.[1] On opening the gate valve, the flow path is enlarged in a highly nonlinear manner with

respect to percent of opening. This means that flow rate does not change evenly with stem travel.

Also, a partially open gate disk tends to vibrate from the fluid flow. Most of the flow change occurs

near shutoff with a relatively high fluid velocity causing disk and seat wear and eventual leakage if

used to regulate flow. Typical gate valves are designed to be fully opened or closed.[2] When fully

open, the typical gate valve has no obstruction in the flow path, resulting in very low frictionloss.[3]

Gate valves are characterised as having either a rising or a nonrising stem. Rising stems provide a

visual indication of valve position because the stem is attached to the gate such that the gate and

stem rise and lower together as the valve is operated. Nonrising stem valves may have a pointer

threaded onto the upper end of the stem to indicate valve position, since the gate travels up or down

the stem on the threads without raising or lowering the stem. Nonrising stems are used underground

or where vertical space is limited.

Bonnets provide leakproof closure for the valve body. Gate valves may have a screw-in, union, or

bolted bonnet. Screw-in bonnet is the simplest, offering a durable, pressure-tight seal. Union bonnet

is suitable for applications requiring frequent inspection and cleaning. It also gives the body added

strength. Bolted bonnet is used for larger valves and higher pressure applications.

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Another type of bonnet construction in a gate valve is pressure seal bonnet. This construction is

adopted for valves for high pressure service, typically in excess of 2250 psi (15 MPa). The unique

feature about the pressure seal bonnet is that the body - bonnet joints seals improves as the internal

pressure in the valve increases, compared to other constructions where the increase in internal

pressure tends to create leaks in the body-bonnet joint.

Gate valves may have flanged ends which are drilled according to pipeline compatible flange

dimensional standards. Gate valves are typically constructed from cast iron, ductile iron, cast carbon

steel, gun metal, stainless steel, alloy steels, and forged steels.

All-metal gate valves are typically used in ultra-high vacuum chambers to isolate regions of the

chamber.[4]

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Globe valveA globe valve, different from ball valve, is a type of valve used for regulating flow in a pipeline,

consisting of a movable disk-type element and a stationary ring seat in a generally spherical body.

Globe valves are named for their spherical body shape with the two halves of the body being

separated by an internal baffle. This has an opening that forms a seat onto which a

movable plug can be screwed in to close (or shut) the valve. The plug is also called a disc or disk. In

globe valves, the plug is connected to a stem which is operated by screw action using

a handwheel in manual valves. Typically, automated globe valves use smooth stems rather

than threaded and are opened and closed by an actuator assembly.

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Fig 1: Internal parts of a typical globe valve. Fig 2: Stainless steel globe valve

Landing ValvesLanding valves are a firemen station in each landing of the building floor which is placed on the wet riser, firemen can connect the fire brigade 1 1/2 " or 2 1/2 '' hoses to the valve to supply them by the required flow and pressure.

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Wet alarm valve

General

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The alarm check valve is a waterflow alarm device designed for vertical installation in the main supply to a wet pipe sprinkler system. When a flow of water from the system equals or exceeds that of a single sprinkler, the valve is to actuate a fire alarm.

The alarm may be accomplished in two ways:

1) Mechanically by means of a water motor alarm and/or

2) A water pressure actuated alarm switch connected to an electrically operated signalling device such as bell or light

The valve seat is tinned. Only the listed components such as retard chamber, water motor gong (alarm), drain valve and pressure gauges will be used.

Operation

When the sprinkler is placed in service, the water is allowed to flow into the system, until the system pressure and the supply pressure are equal. The system pressure, then, causes the rubber-faced clapper of the alarm valve to close tightly on the grooved seat ring. It will remain in this closed position as long as the pressure in the system is equal to or greater than the supply pressure.In the variable pressure conditions, in service, the pressure on the system, most often, will be found to be greater than the water supply pressure. This condition exists because excess pressure from surges and fluctuations in the water supply is allowed to pass through the external checked by-pass to be trapped in the system above the alarm valve clapper. Normally, then, the clapper will remain in a closed position.

Sometimes, however, sudden surges of greater pressure may cause the clapper to open momentarily, then close. In such instances, when the clapper is open, there will be a limited flow of water through the seat ring opening and into the retard chamber. There, the water can accumulate then drain away without causing a false alarm.

When a sprinkler operates, the resulting water flow relieves the system pressure. The greater supply pressure, then, causes the alarm valve clapper to open, thereby permitting an unobstructed flow of water into the system. At the same time, water flows through the seat ring openings and via alarm line connections into the retard chamber. But now, with the system operating, the clapper remains in an open position and the volume of water flowing through the alarm line is such that the retard chamber drain cannot keep up with the incoming flow. The chamber quickly fills and the water flow continues on to sound the water motor alarm and/or operate the pressure actuated electric alarm switch. Caution

All sprinkler systems contain a certain amount of confined air. It is possible that a pressure surge could compress this air and allow the alarm valve clapper to move off the seat ring. Under some conditions, this could cause false alarm. It is recommended, therefore, that the installer bleed off the confined air and fill the system with water to the fullest extent possible.

Constant pressure:

Under normal conditions, the system and the supply pressure will be the same. And since the pressure is constant, there is no need to consider surged and fluctuation. Therefore, a retard chamber is not provided. When a sprinkler operates, the system pressure drops allowing the alarm valve clapper to

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open. At the same time that water enters the system, it also flows through the seat ring openings and then via the alarm line connections directly to operate the alarm devices.

Installation

The inlet and outlet of the alarm check valve are provided with standard flanges. The water flow of sprinkler system should be cleaned off any dirt and foreign matters such as sands and stones. Check the clapper for room of operation before connecting the alarm valve to the flanged water supply piping.

WARNING:

The installation direction must be correct. The arrow direction indicates the direction of water flow, reverse installation is not allowed.

After installation of alarm valve is completed, please actuate the system in the following order:

1) Close the system control valve

2) Close the alarm control valve

3) Open the inspectors check valve

4) Slowly open the system control valve

WARNING:

Be sure to open this valve partially at the start of water flow into the system. Do not fully open at this point; doing so may cause water hammer which could damage the piping and trap large volumes of air within the system.

5) Continue to fill the system until water discharge in stream from the test orifice of the check valve

6) Close the inspectors check valve

7) Turn the system control valve to wide open and watch the pressure gauge

NOTICE:

Be sure to open this valve partially at the start of water flow into the system. Do not fully open at this point; doing so may cause water hammer which could damage the piping and trap large volumes of air within the system.

8) Conduct main drain valve test to make sure that the water supply is sufficient

9) Open the alarm control valve

10) Conduct alarm device test

11) Seal, lock and secure the system control valve, and the system is now ready for service

12) If alarms connect to a central station or fire department, notify that the system is ready for service

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Y Strainer

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Y-Strainers are devices for mechanically removing unwanted solids from liquid, gas or steam lines by means of a perforated or wire mesh straining element. They are used in pipelines to protect pumps, meters, control valves, steam traps, regulators and other process equipment.

Y-Strainers are very cost effective straining solutions in many applications. Where the amount of material to be removed from the flow is relatively small, resulting in long intervals between screen cleanings, the strainer screen is manually cleaned by shutting down the line and removing the strainer cap. For applications with heavier dirt loading, Y-Strainers can be fitted with a "blow-off" connection that permits the screen to be cleaned without removing it from the strainer body.

Y-Strainers are used in a wide variety of liquid straining applications to protect downstream process system components in many industries, including: chemical processing, petroleum, power generation and marine. Water handling applications, where Y-Strainers are used to protect equipment that could be damaged or clogged by unwanted sand, gravel or other debris, are very common

Cast Iron Flanged Strainers feature a machined, tapered seat which ensures a perfect fit for the removable, stainless steel screen. All sizes come complete with flanged blow-off cover, gasket & plug. May be installed in vertical or horizontal pipelines with blow-off connection at the lower end of the screen.

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