Pinch valves can handle a wide range of fluids. Their seating surfaces can accommodate large objects, and they are suitable for food grade applications. Unlike other types of valves, which require a metal surface, pinch valves have no metal surfaces. This means that they can be used in the most demanding applications.
Linear action pinch valves are characterized by a retracted plunger and a retractable piston. When the piston and plunger retract under air pressure, the pinch gap 45 is fully opened, opening the tubing flow path. The biasing member 88 maintains a low pressure at the rear air chamber 89 a and high pressure at the front air chamber 89.
A pinch valve’s body consists of a molded sleeve made of rubber or a synthetic material. The plunger and the pinching mechanism are inside the body. The rest of the operating parts are external to the valve, and are not in contact with the media. To minimize line vibration and turbulence, pinch valves typically have smooth walls. As a result, they can be installed with no packing.
The liner material used for pinch valves is a crucial part of the valve. This useful site material must not only be lightweight, but it should also be abrasion-resistant. Damaged material can deform and prevent flow. This can increase turbulence and pressure drop. It is also not suitable for high-temperature applications.
The sleeve is usually made of multiple layers of fabric. The number of layers depends on the valve’s diameter and pressure rating. When the valve is closed, the fabric layers flex around the metal insert. This is done to avoid fabric fatigue. The resulting overstress can cause the liner to fail prematurely.
Maximum operating temperature
Pinch valves are a versatile piece of valve equipment used in various industrial processes. Unlike other types of valves, which are usually made of bulky materials, pinch valves are lightweight and durable. Pinch valves are typically made from rubber or synthetic polymers. The material used for the body of the valve is usually selected based on its properties and the maximum operating temperature of the media it will handle. Available materials include EPDM, NBR, silicone, butyl, and stainless steel.
Pinch valves can be operated manually or with the use of electric motor actuators. Manual valves use hand cranks or hand-wheels to open and close. Manual valves are not always available. Pinch valves are also available with hydraulic fluid or solenoid mechanisms. Electric motors, pneumatic actuators, and hydraulic operators are available for manual, semi-automatic, and automatic positioning.