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What are isolation valves?

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What is an Isolation valve?

When a valve has been installed in a series of pipes. When the valve is opened, the fluid starts to flow, and when the valve is closed the fluid stops flowing.

Symbol for Isolation valve

Valve like this is tasked to close fully (fully closed) or fully open (fully opened) a flow. Because its job is only to open or close, this kind of valve is called ON / OFF valves or Isolation valve.

All isolation valves should be of the indicating type and NFPA 20 recommends these be listed.

Indicating valves are those valves that provide an easily distinguishing visual method to determine the open or closed status of the valve.

Types of Isolation valve:

Rocker Style Isolation Valves

A rocker isolation valve is a solenoid operated tool that utilizes a rocker system that rotates to seal the seat of the valve and isolate the flow route. As shown in Figure 1, it is possible to configure rocker-style isolation valves as easy 2-way systems or multi-port selector / diverters.

Diaphragm Isolation Valves

A diaphragm isolation valve, also known as a “membrane valve,” is a solenoid-operated device that uses a diaphragm to seal the valve seat and isolate the flow path. Like rocker style valves, it is also possible to configure diaphragm isolation valves as easy 2-way or 3-way on / off systems.

Pinch Valves

A pinch valve is a device that, by pinching a removable, disposable tube, opens and closes the flow route. Although not officially deemed isolation valves, by using this disposable tube, pinch valves conduct an identical role by isolating the valve system from the media.

What is difference between isolation valve & gate valve?

Like all other types of isolation valves gate valves are also a isolation valve.

Gate valves are multi-purpose bi-directional shutoff valves for commercial and industrial applications.

Due to their capacity to cut through liquids, the shut-off action is accomplished by shifting the wedge vertically up / down in the valve body.


Instrumentation Engineer

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