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A liquid flow control valve helps in regulating the motor speed in the application system. It is because of the valve’s ability to affect the energy transfer rate by impacting the flow at any point in the system. The valves provide many roles in flow control, and hence their name, flow control valves.
System operators usually use flow control valves to reduce pressure on the hose, which are serviceable and change their fittings faster. They can also decrease the water amount utilized without interfering with the performance of the whole system.
Like liquid flow meters, flow control valves are applied in various industrial applications such as warehouse equipment, food processing, automated industries, and material handling processes. This article will discuss different types of liquid flow control valves that are commonly used.
1. Globe valve
Globe valve is a type of liquid flow control that helps start, stop, and regulate the fluid flow by initiating a closure that passes through a plug with a convex bottom always located horizontally at the valve center. The plug raises upon the valve opening, and the fluid is likely to flow.
Since one can remove the valve disk or completely close the fluid flow path, globe valves are usually suitable for applications like on or off and throttling operations. However, globe valves can only work where the flow factor is not the pressure drop.
Advantages of Globe valves
i)It is always easy to resurface the seats.
ii) Globe valves are capable of shutting off quickly.
iii) Globe valve has a shorter stroke than the gate valve.
iv) Globe valves have better medium throttling capability.
Disadvantages
i)Globe valves require a greater force to function effectively.
ii) Globe valves require high-pressure drops.
iii) There is a shutoff flow over the seat and a throttling flow under the seat.
2. Diaphragm valves
Diaphragm valves work by distributing force to open, close, and monitor the valves, and it is always flexible and responds to pressure. They usually function with a disc that forms a seal at the top body of the valve. The flow stream is separated from the closure element by the elastomeric diaphragm connected to the compressor.
This valve type of liquid flow control is always ideal for dirty, corrosive, and erosive liquids.
Advantages of Diaphragm valves
i)Diaphragm valves are easy to maintain.
ii) Diaphragm valves have a tight shutoff.
iii) They are extremely clean than other valves.
iv) You can repair them without interfering with the pipeline.
v) Diaphragm valves help in reducing environmental leakage.
Disadvantages
i)Diaphragm body must be made of corrosive resistant material.
ii) Diaphragm valves are not suitable for large diameter pipes.
iii) Some diaphragm materials limit the pressure and temperature.
3. Gate valves
System operators use the type of valve for flow control of the on or off in operations. They work where there is a need for a fluid to flow straight line with fewer restrictions. The operator spins the stem clockwise or anticlockwise to close or open the motion.
Advantages of Gate Valves
i)Gate valves are cheap.
ii) They can operate well on slurries and viscous liquids.
iii) They are available in big sizes.
iv) They have a bidirectional flow operation.
v) Gate valves are easy to maintain and disassemble.
Disadvantages
i)The maintenance, startups, and assembly require ample space.
ii) One cannot open and close gate valves quickly.
iii) Leakage may occur with gate valves in cases where there is high irregular temperature change.
4. Pinch valves
Pinch valves are always suitable for liquids with suspended solids and slurries. They usually form a seal, a rubber tube that turns off the flow after getting pinched. The rubber sleeves are generally flexible, allowing the pinch valves to close around the solid surface for flow control tightly.
Advantages of pinch valves
i)Pinch valves usually have excellent drainage.
ii) Pinch valves have less weight hence easy to carry.
iii) Pinch valves are cheap to purchase and install.
iv) Pinch valves require low maintenance costs.
v) They are very clean.
Disadvantage
i)There is a limitation on the temperature and pressure ranges.
ii)Less space for the valve may lead to issues on face-to-face length.
5. Needle valves
Needle valves are types of flow control valves that work on small lines of fluid flow volume. The flowing fluid moves at a right angle through the orifice that acts as the seat to the tipped rod, which is cone-shaped—the size of the orifice changes when the cone is about the middle.
Advantages of Needle valves
i)One can adjust the flow rate precisely.
ii) It is easy to operate needle valves.
iii) It can provide flow control with a high accuracy level at low rates.
iv) It can throttle with less fluid volume.
v) They are small in size hence easy to carry.
Disadvantages
i)Only suitable for low flow rate piping applications.
ii) Restrictions on fluid flow lead to high-pressure loss.
iii) Solid particles can destroy the needle and the pipe.
Conclusions
Liquid flow control valves come in various types. Consider choosing the best flow control valve for your application with the help of system operators or engineers. Other types include butterfly valves, ball valves, plug valves, etc.
