When compared to other types of valves, pinch valves are a low-cost and highly effective alternative for fluid control applications. These valves are characterized by straight flow paths, very low turbulence and friction, and a self-cleaning feature. They are also very durable and provide excellent performance in open and closed mode, with proportional control.
Pinch Valves are primarily used in wastewater treatment plants, power generation and mineral processing. They are especially suited for slurries and other difficult fluids. They can outperform alternative products ten to one, and are abrasion and corrosion resistant. They are also non-clogging, maintenance free and can even seal drop tightly around solids.
The main component of a pinch valve is the rubber sleeve, which is made from a variety of synthetic polymers based on the corrosiveness and abrasion resistance of the fluid that it will be used with. Sleeve materials include natural rubber, NBR (nitrile), EPDM (ethylene propylene diene monomer) and silicone. They may be reinforced for additional abrasion protection.
Typical pinch valve sleeves are available in sizes that coincide with standard pipe diameters and flange dimensions. These sleeves can be welded onto a body or can be slipped over a pipe end. The sleeve can also be integrated into the lining of the body, allowing the pinch valve to be fitted with tri-clamps, threaded spigots or flanges.
Air operated pinch valves are actuated by compressed air to compress the rubber sleeve and a spring return mechanism allows the sleeve to be released into the open position. These valves are reliable with fast opening and closing times, and are available in manual or air operated versions.
These pinch valves are a great choice for a wide range of industrial and commercial processes, including wastewater treatment, chemical and energy industries, mining, iron and steel production, pulp and paper mills, food and beverage processing, glass, electronics, cement, and sand. They can be used with a wide variety of liquids and solids, including slurries and entrained solids.
There are two main types of pinch valves, shell-and-tube style and mechanically closed pinch valves. The former type is a simple design that can be installed in a variety of pipe and flange styles. The latter is an enclosed design with a metal body that surrounds the sleeve. Both types are available with a full port or double-wall.
Both are available in a wide range of sizes and are suitable for a variety of piping systems, including those that have a high flow rate. These pinch valves can be equipped with pneumatic or electric actuators and pneumatic or electropneumatic position controllers.
Some pinch valves have a throttling option that opens only to 50% of the flow rate, ensuring that only 50% of the full stroke is used. This reduces energy consumption, improves operation and minimizes wear and tear.
The sleeve of a pinch valve is the only part that comes in contact with the fluid that it will be used with, so it needs to be made from a durable and abrasion-resistant material. Depending on the application, a rubber sleeve can be made from natural rubber, NBR (nitrile), silicone, food quality rubber, GRS, Neoprene, Butyl, Buna-N, PTFE, FDA and Hypalon.