what is air to open and air to close control valve and
difference btwn this...and how to measure milli amp by
this...and what is the role of positioner and i/p converter in
this..plz help me
Answer Posted / mohammed abdul rahman
This query is mostly related to pneumatic diaphragm actuated control valves. Air to open valves have the pneumatic input on the under-side of the diaphragm with a spring on the topside, which causes the valve to open on increase in control signal. Air to close valves will have the pneumatic input on the topside of the diaphragm with a spring on the under-side to provide counter force.
An i/p converter will convert the 4-20mA signal from control system to an equivalent 3-15psi pneumatic signal to actuate the control valve.
A positioner will have the i/p converter inbuilt and is connected to the moving part of the valve and automatically adjusts the signal to the actuator to maintain a position proportional to the signal. This introduces a loop inside a loop.
Please refer the control valve handbook from Fisher for reference. It is available as a free download.
| Is This Answer Correct ? | 37 Yes | 4 No |
Post New Answer View All Answers
why we are using magnet for calibration of gas detector?
What denotes the 5/8mm in the 3300XL 5/8mm proximitor probe?
how u choose thermowell lenght n pnumatic C/v size?
what is effect of specific gravity in differential level transmitter , explain formula related with this .
Name different parts of a pressure gauge. Explain the use of hair spring in the pressure gauge.
sir, give me placement papers and interview quistion of birla group company of copper.
what is the difference between attemperator and desuperheater ?
What is Alpha & Beta fctors related to Orifice Plate & its relation with flow?
can anyone tel the syllabus or previous year question paper for BHAVINI(EIE)2014.
In turbine what does term CDP, NH, HSSOC means.
where proximity sensor installed on tank in loading arm application
what effects a surging can produce in the compressor
How r the calculation of process line mpm.
Hi i am aneesh, done btech in applied electronics & instrumentatiin. And then i took mba in finance & marketing.After that i got placement in finance co and worked there for 3.5 yrs.Now i wanted to come back to engineering job.But without engg experience, i may not able to find an opening.i have done a course related to flow meters and ite calibrations. Kindly suggest where should i try to get a job?
What is the main difference between Cavitation and Flashing?