A pinch valve is a full bore or fully ported type of control valve which uses a pinching effect to obstruct fluid flow. There are a few types of pinch valves based upon application.

Fluids

Pinch valves used for fluids usually employ a device that directly contacts process tubing. Forcing the tubing together will create a seal that is equivalent to the tubing's permeability.

Particulates

Major components of a pinch valve consists of body and a sleeve. The sleeve will contain the flow media and isolate it from the environment hence reducing contamination to the environment. Generally used for slurries or processes with entrained solids, because the flexible rubber sleeve allows the valve to close droptight around solids—solids that would typically be trapped by the seat or stuck in crevices in globe, diaphragm, butterfly, gate, or ball valves. The sleeve material can be selected upon the corrosiveness and abrasiveness of the flow media, a suitable synthetic polymer

Synthetic polymer

Synthetic polymers are often referred to as "plastics", such as the well-known polyethylene and nylon. However, most of them can be classified in at least three main categories: thermoplastics, thermosets and elastomers....

 can be chosen. A pinch valve may be the best type of valve for flow control

Flow control

In data communications, flow control is the process of managing the pacing of data transmission between two nodes to prevent a fast sender from outrunning a slow receiver. It provides a mechanism for the receiver to control the transmission speed, so that the receiving node is not overwhelmed with...

 application if the operation temperature is within the limit of the polymer.

Air operated Pinch Valves

Air operated Pinch Valves are very easily constructed. They generally only consist of an extremely elasticised reinforced rubber hose, a type of housing, and two socket end covers or flanges. The rubber hoses of the air operated Pinch Valves are usually press-fitted and centred into the housing ends by the socket end covers or flanges.

Function of Air operated Pinch Valves

The air operated Pinch Valve works without any additional actuator; all it needs to close or operate is 30 psi air supply into the Pinch Valve body. As soon as the air supply becomes interrupted and the volume of air exhausts, the elastic rubber hose starts to open due to its great impact resilience.

Advantage of Air operated Pinch Valves

The most important benefits of using air operated Pinch Valves are their complete and true full bore, and the 100% tight shut off – even on solids such as granules, powder

Powder (substance)

A powder is a dry,thick bulk solid composed of a large number of very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder and granular are sometimes used to distinguish separate classes of material...

s, pellets

Pelletizing

Pelletizing is the process of compressing or molding a material into the shape of a pellet. A wide range of different materials are pelletized including chemicals, iron ore, animal compound feed, and more.- Pelletizing of iron ore :...

, chippings, fibres, slivers, any kind of slurries and many more aggressive products.

Usually conventional valves such as ball valves, butterfly valves, piston valves or gate valves tend to fail when in process with the above mentioned aggressive products. The reason is that the valve body seat or the gate/piston of the valves wears out too quickly and the valve can no longer shut off tightly, whereas air operated Pinch Valves work without almost any wear of the elastic rubber hose because the kinetic energy of the solids are absorbed through the extremely high elasticity of the rubber. The rubber mixture is also anti abrasive.

Industrial sectors

Therefore using air operated Pinch Valves in aggressive product processes saves a lot down time, and guarantees a free flow through the valve, avoiding any blockages.

Several rubber

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

 qualities are available for air operated Pinch Valves such as natural rubber, EPDM, nitrile

Nitrile

A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...

, viton

Viton

Viton is a brand of synthetic rubber and fluoropolymer elastomer commonly used in O-rings and other molded or extruded goods. The name is a registered trademark of DuPont Performance Elastomers L.L.C.....

, neoprene

Neoprene

Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene. Neoprene in general has good chemical stability, and maintains flexibility over a wide temperature range...

 and butyl

Butyl

In organic chemistry, butyl is a four-carbon alkyl radical or substituent group with general chemical formula -C4H9, derived from either of the two isomers of butane....

.
Different housings and end covers/flange materials such as aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

, plastics and stainless steel

Stainless steel

In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....

 are also available;
resulting in air operated Pinch Valves being commonly used in a wide range of many different industries such as:

• Bulk
  Bulk
  -Industry:* Bulk cargo* Bulk liquids* Bulk mail* Bulk material handling* Bulk pack, packaged bulk materials/products* Bulk purchasing- Physics :*Bulk density*Bulk modulus...
  
  and solids handling,
• Cement
  Cement
  In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...
  
   industry,
• Waste water industry,
• Chemical industry,
• Food industry
  Food industry
  The food production is a complex, global collective of diverse businesses that together supply much of the food energy consumed by the world population...
  
  ,
• Beverage industry,
• Ceramic
  Ceramic
  A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
  
  -/Glass
  Glass
  Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
  
  -/Plastic
  Plastic
  A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
  
   industry

plus many more.

On a smaller scale, pinch valves are used in some water pistols, notably the original Super Soaker

Super Soaker

Super Soaker is a brand of recreational water gun, first sold in 1990 by Larami and now produced by Hasbro under the Nerf brand. Invented by Lonnie Johnson on November 13, 1989, the first Super Soaker, the Super Soaker 50, was originally called the Power Drencher...

50.