Pinch valves that enable purchasers to choose specific sleeve compositions and styles for various applications are available from Rhinoflex Pinch Valves . A pure gum rubber sleeve, for example, is not suitable for the handling of strong acids, but might be appropriate for food manufacture or alcohol distillation. The application of a particular pinch valve, including the temperature range to which it will be exposed, dictates which sleeve elastomer a valve customer should choose.
Pure gum rubber sleeves are resilient and abrasion-resistant. They can handle a wide temperature range, from -50°F to 180°F, and they are flexible, as well as non-marking. They are composed of natural rubber, and are suitable for organic or carbon-based acids, and mild chemical compounds, including alcohols. Strong acid and basic solutions, oils and solvents are some of the chemicals that this type of pinch valve sleeve is ill-equipped to handle.
Neoprene pinch valve sleeves are synthetic rubber sleeves composed of chloroprene polymers. They handle a wider temperature range than pure gum rubber sleeves do, working well with temperatures up to 220°F. Neoprene is chemically inert and works best in the handling of moderate acids and other chemicals. Unlike pure gum rubber, it is strong and resilient enough to handle products containing ozone, as well as some oils and fats. Neoprene is resistant to abrasion than is gum rubber, however it can be eroded or weakened by oxidising acids, ketone, ester and chlorinated hydrocarbons.
Sleeves composed of chlorobutyl elastomers or chlorinated butyl rubber compounds, handle major temperature ranges, from -60°F to 300°F. These sleeves are known for their good abrasion resistance and their ability to handle animal and vegetable fats. However, other types of oils are heavy for chlorobutyl elastomers to handle as are solvents, which can break down the rubber.
The trademarked name of nitrile (a triple-bonded compound), Buna-N can be used to make sleeves suitable for -40°F to 240°F temperature ranges. These types of sleeves can be useful in chemical manufacture and chemical engineering because they can handle chemicals and solvents. They are not suitable, however, for ozone, ester, ketone or nitro/chlorinated hydrocarbons.
Hypalon, a trademarked name for a chlorosulfonated polyethylene compound, is used to construct sleeves suitable for temperature ranges between -60°F and 275°F. This durable compound can handle strong acids and bases, as well as Freon, ozone, alcohol compounds and alkalines. This type of pinch valve sleeve should not be used with ketone, ester, or various chlorinated hydrocarbons. Hypalon resists weathering quite well, however.
EPDM (or ethylene propylene diene monomer) valve sleeves are excellent for use with fats and oils. These valves made of the material used to seal vehicle doors, windows, and the like -- can withstand temperature ranges between -60°F and 300°F. They should not be used, however, to work with mineral oils or solvents. Viton, a type of synthetic rubber used commonly in O-rings, can also be used with animal and vegetable oils, as well as with acids. Though this type of sleeve performs poorly at temperatures lower than -10°F, it performs well at temperatures up to 400°F. Viton sleeves also display excellent tensile strength.
Each of the many uses of pinch valves requires careful consideration of the valve sleeve that is appropriate to the process for which the valve will be used. With the variety of sleeve elastomer options available, it is no wonder that pinch valves are applicable in so many situations and for so many processes.