Accessories of Control Valve
Accessories of Control Valve
(OP)
I am a newer to Control Valve. I have some questions about graphs below. The accessories of Control Valve is the strangers to me. Could you help me?
Please see the attachment graphs.
Thanks in advance.
Please see the attachment graphs.
Thanks in advance.





RE: Accessories of Control Valve
RE: Accessories of Control Valve
it seems that the 2 accessories on the right side are volume boosters type Fisher 2625.
Hope it will help you.
RE: Accessories of Control Valve
The first picture is not perfectly clear to me.
- What is evident is that the part in the bottom right is a filter/reducer to make sure you have clean supply pressure that is not overpressuring your actuator.
- The item in the bottom left looks like a selector valve. Normally used for manual override or testing the valve.
- In the top left you have a volume booster. Included to increase the operating speed of the actuator.
- Top middle can be several things. I am not sure, but I expect that these are high capacity filter/reducers.
- Top right looks like just a gauge on a cross-connector. To show the inlet pressure.
The second picture is easier.
- On the right you have a Fisher booster type 2625 as mentioned by Igreca. This is also used to increase the operating speed of the valve.
- On the right is a Fisher trip valve type 377L. This is used for making sure that the valve has a fail function when the supply pressure is lost. The fail function can be fail lock by blocking all exits or fail open/close by connecting one exit to an accumulator. Since the boosters are placed after the trip valve it must be fail open/close, because the fail lock function is overruled by the boosters.
TIP:
You can look at the nameplates of the equipment what the manufacturer and model is.
Best regards,
Terje
RE: Accessories of Control Valve
I have an idea of them.
But I don't know the function of the selector valve of the first graph said by terje61. Could you speak more in detail.
In addition, I have other two graphs to bother you.
This is one control valve with different side photographs.
RE: Accessories of Control Valve
RE: Accessories of Control Valve
RE: Accessories of Control Valve
The new pictures do not make it much easier, but I will write down some possibilities.
A selector valve is normally used as follows:
In position A: port 1 and 2 are connected. The output of the positioner is connected to the actuator via the boosters. The valve works on automatic 4-20 mA control.
In position B: (90 degrees turn): port 1 and 3 are connected. This might be to manually open the valve.
In position C: (180 degrees turn): port 1 and 4 are connected. This might be to manually close the valve.
The manual positions can also be for (partial) stroke testing / valve blocking or any other operation. Without a clear schematic drawing this is difficult to determine.
Getting back to the top/middle item in the first picture this might also be a biasing relay (e.g. make Fairchild). You can use a biasing relay as a trick to increase the actuator pressure and this way select a smaller actuator. In a biasing relay the following equation is applicable: Po = Ps + K
(Po = output pressure / Ps = supply pressure / K is adjustable constant due to internal spring)
This explanation is also applicable for the top item in the last picture and in the third picture.
I hope this helps.
Regards,
Terje
RE: Accessories of Control Valve
I have better knowledge acquisition of it.