Flow control for solids, liquids , slurries and gasses is an integral part of nearly every industrial process, and valves make it all happen! And while there are many types of valves to consider, one very unique choice to consider is the pinch valve.
Pinch valves deliver air and vacuum-tight closure seals (even when closing on solids and granular materials), are extremely abrasive resistant, allow for free flow of material without disturbance due to the full bore opening, are economical and light weight, and can be highly configured for a range of applications – from wine to cement. Let’s have a look at different characteristics that describe any good make of pinched valve.
Controlling mechanism
A pinch valve uses the physical motion of a sleeve to manage the flow of substance through the valve. A simple pinch valve is comprised of a flexible elastomeric diaphragm-like structure (or sleeve) that collapses along the diameter of the valve through the stem to restrict, allow or control substance flow. In air operated pinch valves, the outer air pressure charged into the valve collapses or closes the valve sleeve using air that overcomes the internal line pressure. The pressure differential required to close a pinch valve sleeve varies from 20 – 30 PSI (1.5 – 2 Bar).
In mechanical pinch valves, an outer mechanism, such as a hand crank or pneumatic cylinder, manually pinches the sleeve closed. Devices can also be added to either air operated or mechanical pinch valves to partially close the valve ID or sleeve, there by allowing for throttling or flow restriction.
Function
Pinch valves are mostly used as an on/off switch to manage the flow of non-gaseous media through pipes. There are three main reasons why any good make of pinch valve is used as a flow switch:
- Pinch valves have a full-bore design. This means they can intrinsically allow unrestricted flow and ensure complete stoppage. With this clean and unrestricted valve design, there is no pressure drop through the valve and they are also easy to clean and sanitize.
- Pinch valves are abrasive resistant. When the full bore open valve design is combined various abrasive resistant sleeve materials and flange inserts, the pinch valve becomes the reliable and low-maintenance choice in a range of abrasive valve applications.
- Pinch valves are air and liquid tight, even under pressure. You will not find leaks or messes around a pinch valve, because they do not leak! Nor do pinch valves have hard to replace seals like slide gates and butterfly valves.
Media
Pinch valves are fit for controlling the flow of solid, liquid and slurry media. Hardened steel or stainless steel flange inserts can be added to any metal in contact with an abrasive substance. Alternatively, pinch valves can also be configured to entirely eliminate all metal contact with the interior line substance, thereby making the pinch valves extremely wear resistant to abrasive materials.
Material
Any good pinch valve is made of a light-weight material for easy handling, such as plastic or aluminum or stainless steel. Moreover, the valve body does not necessarily need to be compatible with the line or product material, because they do not come into contact with one another. Rubber, EPDM, Neoprene, Silicon, Nitrile, Butyle, Hypalon and Viton are used for making flexible rubber sleeves (diaphragm) of the valve that are actually ‘pinched’ to control the flow.
Applications
Any good make of pinch valve also stands out among other valve models because it can be employed in every industrial setting. Whether it’s a food processing unit, an assembly handling chemicals or a unit where metallic and ceramic abrasives and corrosives are being handled, pinch valves can be used in handling the material in nearly every industrial and manufacturing process.
AKO Pinch Valves offers a range of pneumatically and mechanically actuated pinch valves and overfill protection systems. The pinch valves made by the company are suitable to be used in every industrial setting.
