Other Valves and Equipments

 

Piston Valve (piston valve):

The piston valve provides control of the movement of the fluid along the line. They are especially used in applications where high temperature and flow is required and where water or steam is used as fluid. Pneumatic valves are usually operated with compressed pressurized pilot air. Compressed pilot air enters the hole in the actuator cylinder and acts on the piston. The piston also provides the removal of the closing element by means of the shaft. Return of the closing element to its former place; either the return spring in the pneumatic actuator or the valve is made double acting, and the pressurized pilot air is supplied from a second position. Pressure limits; Depends on pilot air, direction of flow, hole diameter, piston diameter of the actuator and valve parameters such as spring force. Piston valves are generally manufactured from materials such as cast iron, ductile iron and steel, but as a connection type to the installation; socket, flange and welding are preferred.

 

Needle valve :

The shaft of needle valves is thin and has a conical tip and is lowered along the seat to limit and prevent flow. Flow passing through the valve rotates 90o and passes through the orifice. A good threaded connection to the shaft and a wide seat area allow precise resistance to flow. Needle valves are designed for very precise dosing of very small quantities when required. It is very easy to adjust the dosage thanks to its stroke adjustment. It is easy to maintain and practical. It is very easy to use thanks to its small size and mounting screw. These small valves are used to adjust the flow rate of steam, air, gas, oil, water and other non-viscous fluids at low flows in both on-off and throttle services.

 

Compression Valve (pinch valve):

Compression valves control the flow of media fluid through the hose made of elastic woven fabric. As the name suggests, these valves work with the principle of blocking the opposite walls of the elastic hose so that the ambient fluid cannot pass through. The most important factor limiting these valves is the pressure and temperature values ​​that the elastomer can withstand. Compression valves are generally between DN 50 and DN 300 sizes.

 

Flow Control Valve :

Flow control valve is used to adjust the flow rate or pressure of a fluid. Control valves normally respond to signals generated by independent sources such as flow meters and thermometers. Control valves are usually found with actuators and positioners. Ball and butterfly valves, especially pneumatically controlled globe valves, also lead the valves used for control purposes in industrial areas. Control valves can also work with hydraulic actuators and these are called automatic control valves. Hydraulic actuators respond by opening or closing the valve according to the change in pressure or flow.

 

Pressure reducing valve:

The pressure reducing valve (pressure regulator) reduces the pressure of the liquid or gas from the initial value to the last determined value until the process is completed. It is generally used in hot water and space heating systems.

 

Pilot Valve (pilot valve):

Adjusting the flow rate and pressure of the fluid that will go to the other valves, these valves control higher pressure or flow rate thanks to the small and easy-to-operate and incoming supply. If there were no pilot valves, more force would be required for operation. In addition, they are used in critical applications such as emergency and security control and are operated directly by human beings.

 

Thermostatic Mixing Valve (thermostatic mixing valve):

This valve achieves constant temperatures by mixing hot water and cold water. Thus, it provides adjustment of the water temperature. In this way, it protects against thermal shock or scalding that may occur as a result of errors that may occur during cold or hot supply.

 

Explosion Valve (blast valve):

The explosion valve is used to withstand sudden external pressure changes inside the shelter, especially protecting it from situations that result in injury or death. Sudden pressure change may occur as a result of nuclear explosion or similar explosions occurring in a close area. These valves are placed inside the air inlet / outlet pipes in the normally open position. However, in the event of a sudden and strong pressure change, the explosion valve automatically closes itself.

 

Freeze Valve (freeze valve):

The freeze valve for single phase fluids includes a pipe designed to receive fluid from a cold and hot source through a flow field. Cold welding and hot welding are placed to provide thermal contact with the pipe. In this way, by allowing the fluid passing through the pipe to freeze, it closes the passage in the pipe or allows the passage to be opened by heating the fluid. As a result; The freezing valve prevents or allows the passage by providing both freezing and melting.

 

Diaphragm Valve (membrane valve):

The diaphragm valve fulfills its task by moving a membrane perpendicular to the flow direction and seating it on the sealing surface. It is a valve that is generally used in hygienic applications and is mainly used as a shut-off valve in process systems including fermentation, genetic research, food and beverage industry, pharmaceutical and biotechnological industries.

 

Advantages of Diaphragm Valves:
1. It is used for opening - closing and throttling.
2. Good chemical resistance due to the inner coating of the body.
3. The cover group is insulated from the fluid. Therefore, there is no shaft leakage.
4. It provides bubble tightness.
5. There are no pockets in the body that can cause debris and particle build-up. Therefore, it is suitable for heavy fluids.
6. Particularly suitable for hazardous chemicals and radioactive liquids.
7. Since the cover group is insulated from the fluid, it does not allow germs / dirt to contaminate the environment. Thus, it is hygienic for areas such as food industry, pharmaceutical industry, beer industry.

 

Disadvantages of Diaphragm Valves:
1. If the valve passage is barred, it prevents the pipeline from being emptied completely.
2. Operating temperature and pressure are limited due to the diaphragm material. It is generally used at 200 psi (14 bar) pressure and (204ºC) temperature limits.
3. The hydrostatic pressure that can be applied to the diaphragm is limited.
4. Diaphragm valves are limited in size. It is made in DN15-DN300 sizes.

 

Butterfly Valve (butterfly valve):

Butterfly valve is in the quarter turn valve group. They fulfill their duties by cutting and opening the fluid passage by rotating a flat disc centrally or eccentrically bedded in the middle of the fluid passage hole by 90o.

 

Plug Valve (Conical-Cylindrical ):

The plug valve is a quarter-turn valve and it is seated in a conical or cylindrical slot perpendicular to the flow axis and it fulfills its duty by cutting and opening the fluid passage by turning a conical or cylindrical part with a hole in the middle by 90o and turning the hole to the open or closed position. These valves are used in such a way that they can be on-off or throttling. Plug valves were originally designed to replace gate valves and, due to their quarter turn, can open and close faster than a gate valve. The simplest and common type of plug valve is the two-way one, consisting of an open position that allows flow and a closed position that prevents flow. Since these openings are generally at opposite ends of the body, a quarter turn is sufficient to change from open position to closed position. This is the reason why these plug valves are in the quarter turn valve class. It is also possible that these valves have more than two connection ports. With a three-way plug valve, the flow in the first path can be directed to the second or the third. These paths can work in two or two at the same time, or it is possible for three paths to work at the same time. Although they are mostly used at low temperatures and pressures, there are also those used at higher temperatures and higher pressures. They are generally used in chemical, petroleum, petrochemical, gas transportation main lines by-pass and in pharmacochemical applications. Cast iron, ductile iron, steel, stainless steel and bronze casting, glass, PVC, PP and PTFE are among the most used body materials.

Advantages of Plug Valves:

1. It has a simple design with few parts.
2. Easy to open and close. (Except for big sizes)
3. Maintenance repair can be done at the place of use.
4. It shows minimum resistance to flow.
5. Provides reliable sealing.

 

Disadvantages of Plug Valves:

1. Due to the high friction, it requires great power in the first movement (opening-closing).
2. NPS 4 (DN100) and larger valves require gearboxes or actuators.
3. Depending on the conical plug (plug), the valve passages are of the narrowing type.
4. Generally, their cost is higher than ball valves.

 

Pressure sustaining valve:

The pressure holding valve (counter pressure regulator) adjusts the pressure to the preset upstream level. It is used during pipe installation. It can essentially match the minimum working pressure in the water pipe, keeping the pressure in the pipeline constant by balancing the upstream pressure with the downstream pressure. If the upstream pressure increases, the passages in the pilot are opened more and lower the pressure.

 

Gas Pressure Regulating Valve :

Gas pressure regulators are also used to control the gas pressure, to keep it constant and to prevent damage to the downstream installation and to automatically control the flow of gas at a certain pressure. If the pressure of the gas source is higher than the required pressure, it cuts off the flow. In this case, the valve opens and when the pressure drops, it allows flow until the system pressure rises again.

 

 

Vacuum Breaker Valve :

The vacuum breaker valve ensures that the vacuum level in the system is controlled by allowing contact with the atmosphere when the vacuum level rises above the set value of the valve. The disk or float inside the valve moves upwards, closing the air vent and allowing the flow of liquid as it passes through the valve. When the flow stops, the disc automatically fits to the surface, thus, while opening the vertical direction to the atmosphere, it prevents the pull in the vertical direction. As a result, this valve is often used to prevent dirty water from being drawn back into the pressurized potable water supply.

 

Stub Valve (saddle valve):

Stud valve is used when low flow rate and pressure is required, and it is usually mounted directly on the hose. To do this, firstly, the valve should be placed properly on the line, then it should be turned clockwise until it pierces the water line. If the valve is to be opened, the stem of the valve should be turned counterclockwise. There is no need to interrupt the main water supply during the installation of the valve on the line. It is generally used to supply cold water to humidifiers and ice makers in freezers.

 

Zarp Tap (stopcock):

Zarp faucet is used to limit or prevent the flow of liquid or gas through the pipe. It is generally used in laboratories, steam engines and also to prevent water from flowing into local water systems when events such as flooding are encountered.

 

Comb Valve (reed valve):

The comb valve is a simple one-way valve, but consists of two or more flexible materials pressed together in lengths.

 

Faucet (tap):

Faucet is a simple valve that is used in homes and allows the adjustment of the water flow. It controls the discharge of liquid or gas. Examples are sinks, bathtubs, laboratory and beer taps.

 

Screw Faucet (bibcock):

The screw tap is used to connect the hose to the water supply outside the buildings. Especially car washing and garden irrigation are the most frequently used applications of such valves.

 

Float Valve (fill valve / ballcock):

The float valve is used to control the water level and prevent overflow during filling the water tanks. Usually found in toilet flushes. The valve, which is the most important element of the mechanism, is attached to the float and is located near the top of the tank. The valve is connected to the source where the water comes from and is opened and closed with the help of a lever. If the water level has reached the filling level, the float forces the valve to close. This causes the valve to stop the flow of water. When the water level in the tank decreases, the float lowers and activates the float valve and the water starts to fill the tank again. This filling continues until a certain level is reached.