Chemical plants are mainly used Pinch valves in order to regulate the flow of slurries in certain processes and systems. These valves have flexible bodies that can be shut by pinching them. They are often used when it is necessary for the slurry to pass straight through when the valve is not pinched.
The pinch valve is used to shut off the abrasive and air flow through the blast hose after it leaves the metering valve. The pinch valve is normally open and requires a compressed air supply to close it. Most commonly used on pressure hold blast systems. As no abrasive passes through the valve it is not subject to wear. When the portion of blast hose being pinched wears out it is simply cut off and a new section inserted.