in the boiler in the main steam line and its bypass line and
the startup vent vales are only motorised valves why cant we
use other types of valves such as pneumatic.
Answer Posted / sam
The design engineers must have had a reason why they
selected to use motorized valves in stead of pneumatic
valves. It might be that they felt the main power is less
likely to fall away than the plant air compressor tripping
and there is no air to operate these valves. It also
sometimes happens that the main instrumentation supply UPS
(24VDC) will trip and the whole plant looses the
instrumentation supply but the main supply is still available.
Also if the main power do fall away there is always the
emergency generators that will kick in and supply emergency
main supply to all the critical systems.
Just for interest they tend to select motorized valves for
safety systems as well like foam, fire pump control valves
and deluge main control valves, most probably for the same
reasons.
Good luck
| Is This Answer Correct ? | 5 Yes | 2 No |
Post New Answer View All Answers
how do u calibrate the vacuum transmitter if it shows more reading
Define the terms Accuracy, precission, Spam, process tolerance while doing calibration of an instrument? Explaini with an example?
Why mmwc unit is used?
Explain the working of an enraf level gauge.
What is intrinsically safe system?
what is sil (safety integrity level
Difference between ultra sonic flow meter
DEAR SIR/MADAM MY NAME IS ARKAPROVA BHATTACHARYYA.I AM A FRESHER INSTRUMENTATION ENGINEER.CAN YOU PLEASE SEND SOME QUESTION PAPERS OF GRADUATE ENGINEER TRAINEE EXAM OF DVC(DAMODAR VALLY CORPORATION).MY EMAIL IDs ARE arka_aec@rediffmail.com.
can u briefly explain aboutan aryton shunt multirange DC ammeter?
you are on site,the plant trips,you are approached by operations,what do you do?
In dcs panel we are using diff type of modules ?what is module ? what is the use of modules ?diff type of module?
any body please send me the old question papers of ongc test.
what is interface level and how it is calibrate?
Please asked me How calculate DCS controller memory.
(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.