I heard of shutdown valves, pressure relief valve, flow control valve, temperature control valve. How does control valve function? anyone?
The control may be just a on/off valve (you just mentioned shut down; maula type); or a modular type.
The on/off valve have limit switches or proximity sesors and are wired to your control board to receive signal; equally for penuamtic actuator the solenoid can be energized for necessary action and for electically actuated one neccesary control signal can be provided.
The modular ones have valve positioners (on the valve) and tramitters which are connected to PLCs and you can position the valve through out its full flow capacity from 0 to 100% therotically.
It may be butterfly/globe or other special type.
Just go by Fischer site for seeing more possibilities.
positioner gets a signal from a controller and send it to actuator in pneumatic form which cause valve stem to travel open or close.
Flow Control Valves and Temperature Control Valves are a subset of Control Valves.
Control valves are ususally an actuated valve that operates over a range (3-15psi, 4-20mA, etc), not just On/Off. They can be ball, butterfly, globe, etc type valve. Control valves can control a mulitple of variables, like Temperature, flow, pH, pressure, level, etc.
No. Each valve has a different mechanism.
A valve of shutdown is not possible relief pressure, the valve of shutdown only open and close and the limit of regulate the pressure is the 15% from open to close. The valve control is the most versatile valve and deppend of the configuration the device of control installed, to make differents function
how pump control, fill the reservoir, open when the pressure is high, slow open, control of flow, and other function, but deppend of the differents solenoid valve, regulator connected on the body of the valve.
See bermad, singer, pratt, keystone, watt and other information. All the last valves are the great quality.
In general a electric control valve will have a way transducer and a normal drive motor which helps to open/close from 0~100 %. The input was setted to open or close (with gradiant some time) through parameter in the seconds. if the delta difference high with theoretical calculated value then the command goes from PLC to close for seconds. and is opposite if theoretical value goes hi. Means Control valve Closes until accumulating value reach equal to setpoint value. and opposite. The way transducer sends the position of Valve to Controller in 4~20mA a0 0~10 V to view the operator through HMI.Transmitter sends the status (Pressure, flow, level... Etc.) of media to the controller.
If u have more question in control valve feel free to mail me...
Hi this is anuraj here and I found your explanation interesting, but can you tell me how the control valve works logically (logics). Please tell me in detail if its possible for you as I don't have much knowledge for the same.
Thanks and Regards
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I think it;s very hard to apply logical thinking to something like a control valve.
An On/Off valve is either open or closed but a control valve can be anywhere in between.
Think about filling a glass from the kitchen tap, logic says you should open the valve but after cleaning up the mess when your wife yells at you next time you will just open the valve a little bit.
In principle Control Valve is use to control either pressure, temperature, liquid flow, velocity and etc by controlling its plug or disc opening (close, partially open or fully open). It is almost the same as mechanical valve, the difference is that mechanical valve manually control by twisting its handle but for control valve, plug@disc will be controlled by actuator (either by pneumatic, hydraulic or electrical drive). Shutdown valves, pressure relief valve, flow control valve, temperature control valve get their name base on their functionality.
If you want to know more about control valves (selection, sizing, cavitation, leakage standards...) please visit this site :
Learn the basics of instrumentation and process control. Start now and you will get hundreds of articles sorted by theme and ready to download.
below is good control valve reference book :
Hope this help