On drum level, why we are using air to close Control valve?
Answer Posted / carl_ellis
If the valve's actuator is Air-to-Close, what state does it
fail-safe state?
Check out the article, "How to destroy a boiler - Part 1"
at this link:
http://www.nationalboard.org/index.aspx?pageID=164&ID=238
and scroll down a couple pages to the section entitled "Low
Water Conditions".
The description will provide details that help you
understand what the fail-safe state due to the loss of a
control signal on a boiler feedwater control valve should
be.
Carl Ellis
Measure First
| Is This Answer Correct ? | 4 Yes | 3 No |
Post New Answer View All Answers
Why is it necessary to use compensation leg to measure the liquid level in a closed or pressurized tank?
䑰ҕ䔈ҕ䖠ҕ䘰ҕ䛀ҕ䝐ҕ䟐ҕ䢐ҕ䥐ҕŹ
I faced several time siemens ps2 positioner automatically getting Chang in it's set point direction after auto calibration So is there any causes biside this or any permissives ?
Draw a great bridge circuit.
Please can anybody help for control valve sizing step by step procedure?
Instrument QA/Qc what is the project quality plan?conduit inspection RFI. which documents attache with package?
What is Cavitation in a control valve?
you are on site,the plant trips,you are approached by operations,what do you do?
Specify ideal accuracy of flow element like orifice plate, Ventury, Annubar. Ultrasonic flow meter etc.
Describe the typical instrumentation used in monitoring the performance of a shell and tube heat exchanger.
What should be the main consideration while starting the Rotating compressor when we dont know the cut in and the cut off pressure setting of the pressure switch
Explain the working of an enraf level gauge.
Q- Control problem are mainly classified in _____ types. a-)4 b-)3 c-)6 d-)nono of these Few of them i know is 1- regulator type problem (eg- Air conditioner) 2- tracking problem (eg missile trcking problem) 3- sybernatics 4- optimal control problem
(1) In turbine, what does term CDP, NI, NH, HSSOC, means. (2) What is the purpose of LO overhead tank in turbines.(3) An equipment is certified for EEX, IA, IIC,T6, what do you under stand by this.(4) what is SURGE, and how it is prevented, what is the purpose of bypass valve across AS valve.(5) Give 2 application of quartz crystal used for process parameter measurement.(6) what is meant by cold float of compressor shaft. (7) state four different types of flow measurement. For gas flow measurement mmscfd is the common unit. Expand the unit and specify significance of word S in the unit.(8) what is meant by Gap voltage, in vibration measurement. Normally how much Gap voltage is set and state the reason.(9) what will the new flow factor if D/P transmitter is Re-Ranged from 25” wc to 50” wc.(10) what is the usage of QDV & Volume booster.
What are different types of valves?