A pinch valve uses pressurized air to open or close it. It is a full bore or full ported control valve. When there is fluid moving inside, to control or obstruct the flow, a pinching effect is used which gives the name to the valve. When the valve is open, a large range of fluids can pass through.
You can get an idea of basic pipe valves by checking out the Ventomat blog. When it comes to pinch valves, there is a flexible rubber sleeve inside the valve to isolate the media so that there is no risk of contamination. Generally, you use these kinds of valves for granular media or slurries. Some examples are powder, chipping, gravel, carbon, sand and cement. They are an easy to use valve and they are highly reliable. And these are also cost-effective making them accessible for many applications in the industrial field. There are three components of a pinch valve that are the end connections, an internal rubber sleeve and the housing. The rubber sleeve stretches from the inlet to outlet inside the housing and this is the only part of the pinch valve that comes into contact with the media. There are several ways that end connections are connected to each end. Sometimes they are threaded, screwed or they can also be bolted. These connections are what support the valve. When there is pressurised air applied to the valve, the rubber sleeve is pushed down which is what creates the pinching effect.
The flow of media inside the valve will be blocked completely when the rubber sleeve is fully pinched and this is what indicates that the valve is closed. When there is no external air pressure exerted on the rubber sleeve, the valve opens due to the force of the flowing media. This is further helped along by the elastic rebounding of the sleeve. Along with no contamination, having the media only touching the rubber sleeve ensures that there is no damage done to other components. There can be abrasive media striking the rubber sleeve with force. But the material is able to absorb the impact without sustaining any damage. This force is then returned back to the media due to the resilient property of the rubber sleeve. This ensures that the sleeve wears slowly allowing you to use the valve for a longer time.
A pinch valve can actually clean itself. This is due to the stretchability of the rubber sleeve. The rubber sleeve will stretch when closing the valve and this causes any scale build-up to fall off. This is further helped along with the fluid velocity of the media. There are different types of pinch valves. There is a clamp valve that uses a compressor for the clamping mechanism. A flexible tube or clamp is used for this pinch valve. And a full bore will be possible with an air operated pinch valve. These are ideal for shutting off solid media like pellets and granules. And you can achieve a tight shut-off without a problem.