what is the difference between the pinch valve and gate valve / knife valve? If someone can help me explain / show me the complete structure of pinch valve and the way it operates, thats better
a pinch valve has a membrane (or sleeve) inside the valve. When the valve handle is screwed down the membrane is pinch closed. This type of valve is good when the flow needs to be finely controlled. It is also good for slurry (abrasive) flows, as the membrane can be replaced when worn. Gate valves are less effective when the flow must be controlled. They are not used in slurry applications at all, as the gate will be quickly worn away. Knife gate valves can be used in slurry, but are generally totally open or totally closed. The valve must be installed the correct way around, as when closed the weight of the product against the knifegate helps seal the valve. If you have the wrong way around it will tend to leak.
