Pinch Valves 101
Wednesday, September 26, 2018
Pinch valves are one of the simplest valve designs available. They use a flexible elastomer body that can be pinched to stop the flow of granular solids, liquids, slurries or gasses. Pinch Valves are commonly used to start, regulate, and stop product flow using a tube or sleeve.
Advantages and Disadvantages
The pinch valves are designed in such a manner that they provide extensive advantages. They are low maintenance, lightweight, and have excellent resistance to abrasive materials. Pinch valves also offer excellent drainage, minimum turbulence, and allow for sanitary cleaning when necessary. Furthermore, they are cost-effective and gas tight. However, their design does have some disadvantages. The elastomer body of the valves does not operate in services that need high-pressure flow and high-temperature.
The industrial valves can be used for two main purposes. They can be used for the on/off function or as a throttling service.
These valves are the best for such services because of their straight design that allows for an uninhibited flow of fluids. Such a design also has a very little pressure drop between the inlet and outlet.
The effective throttling range is between 10% and 95% of the rated flow capacity.
These valves are essentially used for a wide range of materials, including granular solids, liquids, slurries (liquids with suspended solids), and gasses, including pneumatic transport systems that carry solids using vacuum or pressurized air. The pinch valve is suitable for controlling abrasives and corrosives as there is no contact between the metal part and the transport medium. Because of this separation, these valves can also be used in applications where metal contamination or corrosion is a problem—sewage treatment and sand-entrained water systems.
For liquid applications, the liquid should be constantly moving so that the displacement of the fluid by the sealing areas does not lead to additional strain on the liner, causing it to burst.
The body design of the valves comes in three designs:
- Pneumatic Actuation Valve — Air Operated Pinch Valves use compressed air, up to 150 PSI, to collapse the flexible rubber sleeve. These valves are typically made from Aluminum or 316 Stainless Steel. Various options for product contact parts include aluminum, 316 stainless steel, hardened steel, and numerous rubber and flexible sleeve options.
- Mechanical Actuation Valve — Mechanical Actuation Pinch Valves use an actual mechanical cylinder (typically air operated) or screw actuation method to mechanically force the elastomer sleeve closed. These mechanical actuation pinch valves also have various product contact options, including aluminum, cast iron, , 316 stainless steel, hardened steel, and numerous rubber and flexible sleeve options.
- Manual Actuation Valve – Manual Actuation Pinch Valves use hand cranks to close or throttle the pinch valve sleeves using human effort. So think of something similar to an outdoor water faucet, except one that never breaks and never leaks!
This part controls the stem and the disc that opens and closes the valve. These valves are available with different types of actuators:
- Manual operated— makes use of a hand-wheel or crank to open and close the valve.
- Solenoid operated— makes use of hydraulic fluid to automatically control valve opening and closing.
- Electric motor actuators— allows for manual, semi-automatic and automatic operation.
- Pneumatic operated—automatic or semi-automatic.
- Hydraulic operators—allows for semi-automotive or automatic positioning of the valve.
Pinch Valves offer a great diversity of product contact materials for sleeves, which allow for configuration in all types of industrial applications. Sleeves are also fabric reinforced to extend life and durability. Common materials include:
If you want to know more about pinch valves and their application, contact AKO. We offer the widest and most flexible range of valve configuration options at the most reasonable and affordable prices.
- Neoprene – Resistant to dilute solvents, oils, acids, lubricants, various hydrocarbons and mild chemicals. Applications such as animal oils, natural gas, printing ink and soaps.
- Natural Rubber, Food Grade – Suitable for many weak chemicals, potable water, wine and alcohols.
- Natural Rubber, Abrasive Resistant and High Temp – Excellent abrasive resistance with a high degree of flexibility and durability. Ideal for foundry sand, silica sand, metals, waste water, mineral slurries, cement, concrete, granules and plastics.
- EPDM – Great for higher temperature applications such as hot water, steam, foods and CIP applications where elevated temperatures are used. Also excellent for dilute acids and alkalis.
- Viton – Resistant to solvents, oils, petrochemicals, aromatic hydrocarbons. Applications range from battery acid to buttermilk.
- Silicon – Highest temperature material mainly used to exhaust very hot steam or sulfuric acid.
- Nitrile – Best suited for products with oil or fat content. Examples sewage with trace oils, milk, butter, chocolate, fish, vegetable oils, olive oil, mineral oils, processed beef meal, etc.
- Hypalon – Similar to Nitrile and EPDM applications. Applications such as chloride, peroxide and acids.
- Butyle – Various chemical applications such as alcohol, amino acids, barium, ammonium, and acetic acids.