What is Pinch valve?
- The flow of corrosive, abrasive, or granular media can be stopped or controlled with the help of a pinch valve, a two-way valve.
- To open or close the valve, compressed air is used.
- The valve has no limits while it is in the open position, allowing a variety of media to pass through the bore. The valve’s flexible internal rubber sleeve separates the media from the rest of the valve, preventing contamination or harm to the other parts of the valve. A pneumatic pinch valve is shown in Figure as an example.
- The elastic rebounding characteristic of the rubber sleeve, along with the force of the upstream flow, fully opens the valve when pressure is no longer applied to it.
- The fully opened valve permits unrestricted media flow, preventing clogging or valve blockage.
Operating Pressure + Maximum Pressure Differential = Maximum Control Pressure
- The cavity between the rubber sleeve and the valve body is in communication with the atmosphere when the control air is not input into the pneumatic pinch valve, and the rubber sleeve is in an outward tension state when subjected to fluid pressure.
- The length and diameter of the sleeve won’t vary as a result of fluid pressure since the reinforced plies are positioned at an angle within the sleeve, balancing the axial and radial pressures.
- The pipe sleeve is distorted and blocked by the pressure of the control gas when the control air enters the space between the pipe sleeve and the valve body.
- Pinch valves that function automatically use pressurized air, hydraulic fluid, or a solenoid.
- The result is the same regardless of the tiny differences in the three automatic pinch valve kinds’ operating mediums.
- Using pressurized air, a pneumatic pinch valve tightens the middle of the sleeve.
- A hydraulic pinch valve achieves the same result by using hydraulic fluid.
- Finally, a plunger that pinches down the sleeve is moved by a solenoid pinch valve, which operates on an electric current.
- Slurries and granular goods including sand, cement, gravel, textile fiber, carbon, powder, pellets, chipping, and glass shards are suitable for use with pinch valves.
- The reliability, affordability, and use of these valves make them desirable in a variety of industrial applications.
P&ID Symbol for a pinch valve
This symbol are used in piping and instrumentation diagrams (P&IDs).
Advantages
Because of their distinctive design, pinch valves have the following benefits:
- Excellent with caustic and abrasive media
- Straight flow channel and no media blockage
- little friction and turbulence
- prevents microbial contamination of media
- Minimal maintenance expenses and easy rubber sleeve replacement
- superior sealing abilities
- Fast opening and closing times
- a minimized energy consumption
Disadvantages
The following are a few pinch valve drawbacks:
- The pinch valve sleeve’s elastic nature makes it unsuitable for high-temperature applications.
- The rubber sleeve may collapse or distort as a result of the high pressure differential, which will prevent the valve from opening completely.
- The valve is inappropriate for vacuum applications because internal suction could cause the sleeve to collapse.
Applications
Pinch valves are used in industrial applications more and more due to their benefits. Industries that employ pinch valves include:
- Food and beverage industries:
Nitrile, natural rubber, and EPDM rubber sleeves, which are all FDA-approved for contact with food, are used on sanitary pinch valves. Moreover, a pinch valve cycles quickly, considerably enhancing the efficiency of the package.
- Pharmaceutical sector:
Sanitary pinch valves are an excellent option because the pharmaceutical industry, like the food industry, needs cleanliness.
- Chemical industry:
There are many different uses for the chemical industry. Because there are so many different materials that may be used to make pinch valve sleeve manufacture, pinch valves can handle many of these applications.
- Industry of cement:
Natural rubber pinch valve sleeves are strong enough to endure the abrasion of cement.
Pinch valves provide the abrasion resistance required for handling large and solid materials. Solids cannot block the valves because of their full-bore aperture.
- Ceramic industry:
Reinforced rubber sleeve pinch valves can withstand the extremely abrasive ceramic flow.
- Industry of plastics:
Pinch valves are appropriate for transporting plastic nibs and pellets, which could block other types of valves.
- wastewater sector:
Pinch valves are used in the wastewater sector as pressure relief and shut-off valves.