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Angle Valve

09/19/2008 10:55 PM

Hi

Can anyone please tell me inwhich conditions we use angle valve? and also tell me what is the difference between pressure relief valve and pressure safety valve.

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Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

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#1

Re: Angle Valve

09/21/2008 1:57 AM
  • The Angle valve is used as a valve in addition to change the flow direction by 900.
  • Relief valve (RV) automatic system that relief by static pressure on a liquid. It specifically open proportionally with pressure increasing.
  • Safety valve (SV) automatic system that relieve static pressure on a gas. It specifically opens almost straight to full lift after a pop sound.
  • Safety relief valve (SRV) automatic system that relief by static pressure on both gas and liquid.
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#2
In reply to #1

Re: Angle Valve

09/21/2008 2:38 AM

The angle valve is a valve for controlling the flow of a liquid or air; the fluid leaves at right angles to the direction in which it enters the valve.

Angle valve

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#7
In reply to #2

Re: Angle Valve

09/22/2008 11:46 PM

Hi Dear,

Your comments were really helpfull for me. Is it also used if we want a greater pressure drop?

Regards

RAJ

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#3

Re: Angle Valve and PSVs

09/21/2008 6:20 AM

For me there is no difference between a pressure safety valve and relief valve. Maybe a process engineer or instrument engineer that makes P&IDs for the oil and gas industry will answer. I work for an oil company and see 'PSV' symbols used equally on oil or gas. I rarely see PRV utilised but I think it is cultural. PSV says it better to young engineers. PRV is not a specific description, culturally, regarding the true reason we use it . . . that being 'safety'.

I use angle valves to control velocity erosion through the valve, and they tend to be more controllable. With a globe valve, there is a bit of a tortuous path inside the valve itself, 2-3 turns and 2-3 chances for erosion. I blew out the bottom of a globe valve in 45 minutes due to erosion and replaced it with an angle valve that lasted years, for example. Angle valves have one turn of the fluid. They are known for high velocity erosion control. You can use them in either direction. Pressure can help close the "plug" or fight the "plug". Fighting against the plug is more controllable. The valve sales person will recommend the best direction of flow. Other than just piping configuration convenience, think of angle valves as erosion control valves. At least that is what I use them for. You can just call a valve manufacturer also and ask them, but call 3 sources ! 50% of all valve engineers graduated in the lower half of their class.

Cheers!

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#10
In reply to #3

Re: Angle Valve and PSVs

09/23/2008 11:21 AM

With any globe valve the direction of the flow is crucial. The pressure should always enter the valve so that it is pushing against the bottom of the steam. If it is installed backwards the pressure will push against the side of the stem making the valve hard to close and possibly bending the steam. Globe valves are used to control pressure much like a needle valve would be used on small air or gas lines. Gate valves control flow but unless it is a V-port will not control pressure. A good use for a globe valve is for a bypass around a automatic pressure reducing control valve so that one can manually control the pressure if the automatic valve fails. Many times a knife gate valve will have a flow arrow because it may be designed to seal on one side of the gate and not have a double side gate seal. These work well and save money if you only have flow in one direction and are not shut down with a back pressure such as stock lines on paper machines.

Pipewelder

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#4

Re: Angle Valve

09/21/2008 7:50 PM

Hello RAJ KUMAR:

I think the post by Abdel Halim Galala covers all the info' you ask about.

As I understand it, an angle valve can be used to relieve pressure and, adjust pressure by fractionally opening it. As on a radiator system.

A pressure relief valve is automatic. The design of the valve releases it above a certain applied pressure either by liquid or gas.

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#5

Re: Angle Valve

09/22/2008 12:45 AM

I started in 1962 on Nuclear Submarines and retired in 2002 from a Chemical plant.I worked with valves the whole time including the testing and setting of relief and safety valves.

A pressure relief does what it says.It simply relieves pressure.Normally they are designed to re seat their self when the pressure drops below the relief setting.Normally a pressure relief valve is used with a Safety valve in the same system.The pressure Safety valve being set at a higher pressure.The safety valve is not normally made to reset.It has to be manually reset or repaired.This is never to be done until the problem causing it to relieve is found and fixed.A Rupture Disk is a pressure Safety valve or device.All pressure safety devices are used to prevent catastrophic failure to a system or prevent a dangerous situation.This is the relationship to each other and the way they were used in my 40 years of maintaining and working with these valves.

A safety valve is a very critical and important device.It is NEVER to be abused or used wrongly in any way.To do so can and often has resulted in human deaths.alfred

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#8
In reply to #5

Re: Angle Valve

09/23/2008 12:01 AM

Dear Sir,

Your comments are very precious to me. Could u please give your e-mail address so that i can get further knowledge from u regarding other issues of instrumentation.

Regards.

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#6

Re: Angle Valve

09/22/2008 4:20 AM

Hi,

Regarding pressure relief valve : We can use this valve in hydraulic systems to relief the pressure by means of some qty of fluid diverted to tank.

Regarding pressure safety valve : In air lines safety by releasing the air in to atmosphere, Not to any tank or vessel.

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#9

Re: Angle Valve

09/23/2008 11:07 AM

Hello, As always Abdel Halim Galala is correct and he gets my good answer. One thing I would like to add though is that here in the mill I work at an angle valve is a valve where the stem is not perpendicular to the body of the valve but is on a 45 degree angle. These valves are usually globe type valves although I have seen them with gates occasionally. We usually get these valves in either butt weld or socket weld and many times they will be made of chrome-moly alloy for the higher steam pressures (850+ PSI) and temps(650+ F). The valves that have the flow direction change built in to the body are angle vales also but we don't see as many where I work at as we do the type I am speaking of.

pipewelder

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Users who posted comments:

Abdel Halim Galala (2); Anonymous Poster (1); babybear (1); GSSVSIVAKUMAR (1); PetroPower (1); pipewelder (2); RAJ KUMAR (2)

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