Flow direction in the needle valves 1

[themad1]

Hi!

Usually the manufacturers indicate on the needle valves the direction of flow which must follow the fluid.
Generally, the fluid is conveyed from under the shutter, passes into the chamber of the bonnet and then exit.

But can the needle valves be used in the opposite direction? What there may be any negative impact using on the contrary?

I cannot find any real indication about this question from the manufacturers.

Thanks and regards

Daniel

 

[pennpiper]

You may not find the specific information for Needle Valves but the reason is the same as for a Globe Valves.

Some Globe Valve manufacturers advise NOT installing a Globe Valve backwards because in the closed position the higher pressure fluid is on the top (or stem side) of the disc. This has the High pressure fluid (or Gas) against the Packing (around the Stem) and will cause leaks faster/sooner than when installed in the conventional manner.



Sometimes its possible to do all the right things and still get bad results

 

[LittleInch]

It also means that the high pressure is forcing the needle into the seat. Thus you need a higher force to open it, but the lower the pressure on the stem is also a key point.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Compositepro]

There is also a class needle valves used as flow/speed control in hydraulic power systems. These valves also contain a check-valve that bypasses the needle so that there is restricted flow in one direction and unrestricted flow in the other direction. These valves always have a directional arrow. They are mainly used to control speed of hydraulic cylinders.

 

[Ahdebus]

It's a no no for reverse flow. Mainly due to the high pressure acting on the seat. We're talking the range up to 10000psi.

 

[gerhardl]

Depending on pressure, fluid, flow and type/quality and fabricationreverse flow is OK(and allowed by manufacturor) for some type of NOTE standard types of needle valves.

 

[themad1]

Thank you everyone!

 

[Manichum]

Why would you want to use it in the reverse direction?