Open Body Packingless Zero Leakage Pneumatic Pinch Valve Epoxy Coating Carbon Steel

Epoxy Coating Carbon Steel Open Body Packingless Zero Leakage Pneumatic Pinch Valve

Description

Pinch valves are full bore, linear action valves that can be used in both an off / on manner or in a variable position for throttling service.

Method of Control

Pinch valves use a liner motion method of control. The disc is a flexible material liner, similar to a diaphragm. The stem of the pinch valve has a free-moving connection to a moving closure bar, called a compressor, which is located directly above the liner. As the handwheel is turned, the compressor lowers the liner to squeeze the liner against the bottom support to close the valve. The pressure of the media in the valve can help in starting or stopping the flow.

Function

Pinch valves can be used for On/Off, as well as throttling services.

Pinch valves are ideal for on/off services because of their straight through design that allows for uninhibited flow. Straight through designs also have very little pressure drop between the inlet and outlet.

The effective throttling range of a pinch valve is usually between 10% and 95% of the rated flow capacity. The best flow control is at the last 50% of the stroke. This is because the smooth walls and resilience of the liner do not provide a significant pressure drop until at least 50% of the stroke has been achieved. To avoid using the ineffective half of the full stroke some pinch valves are designed for maximum opening at 50%. It is not recommended that media with sharp particles are throttled close to shutoff. The particles can scratch the liner, causing grooves that could potentially tear.

Material