adjustable port valves
adjustable port valves
(OP)
Merry christmas,
Can anyone explain the usage of the adjustable port valves? By adjusting the port size, we can change the valve capacity, right? To restrict the flow (when fully open) to a very low level, do we need a restrict orifice, or the adjustable port valve can do it itself? Thanks.
Can anyone explain the usage of the adjustable port valves? By adjusting the port size, we can change the valve capacity, right? To restrict the flow (when fully open) to a very low level, do we need a restrict orifice, or the adjustable port valve can do it itself? Thanks.





RE: adjustable port valves
The port opening size is changing for all control valves compared to on/off isolation valves. Also, valves are available with port size selections. Many reduced port (bore) ball valves have a port one line size smaller than the piping. Reduced port sizes for control valves permit trim selection applied to specific process condition ranges. However the valve internals must be replaced to change the port size.
RE: adjustable port valves
RE: adjustable port valves
The CV is adjusted by moving a pivot point to vary the length of a lever.
Rpy
RE: adjustable port valves
Groth has/had a tank-blanketing regulator with a rotary-positionable cylinder around the trim so the user could dial in the capacity he needs for the application. A window in the cylinder could blank off part of the waterway so that the regulator's capacity was adjustable.
Most adjustable Cv valves are as JLSeagull mentioned: pop out the trim, snd insert something of a different size orifice..
RE: adjustable port valves
Yes, we do a lot of prototype gas skids the VariPak is a good fit for that because you can re-use the same valve for different conditions without having to change trim. Another favorite is Badger Research for small globe valve. I particuarly like their stepper motor actuator as it allows you to adjust the range of travel also with very little hysteresis.
Regards & Happy New Year
Roy
RE: adjustable port valves
RE: adjustable port valves
Connection type - screwed or flange
Material
fail action
Control method - 4-20, pneumatic, Foundation Fieldbus
Hazardous area class if applicable
Protection Class - e.g. NEMA 4
Any certification requirements
Process Conditions
Fluid you are trying to control
Inlet pressure
Outlet Pressure
Temperature
Normal & Maximum flow rate (What is MMscfm, I'm not familiar with that unit?)
Any good vendor of control valves will calculate the Cv for you.
I'm not sure that you need an adjustable port valve. I suggest you look at Badger Research they have lots of tiny valves.
If it's a lab type situation you can automate any of the small needle valves from Swagelok or Parker with an actuator from Hanbay
Regards
Roy