【Daily Question 20090405】Selection of air-operated control valves: air-open or air-close
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Under which circumstances should a pneumatic control valve with a certain mode of operation be selected? ([ ) Open or Closed]): 1) The control valve at the compressor inlet should be of ( ) type. 2) The compressor bypass control valve should be of ( ) type. 3) For the compressor outlet pressure control system, when the control valve is installed on the vent line, the ( ) type should be selected. 4) The steam outlet control valve for the drum should be of ( ) type. 5) The drum feedwater control valve should be of the ( ) type with a right-mounted auxiliary positioner. 6) The control valve for the storage tank pressure regulation system should be of ( ) type. 7) For the storage tank level control system, when the control valve is installed on the inlet pipeline, the ( ) type should be selected. 8) For the storage tank level control system, when the control valve is installed on the outlet pipeline, the ( ) type should be selected. 9) For the fuel oil and gas system of the heating furnace, ( ) type should be selected. 10) For the feeding system of the heating furnace, ( ) type should be selected. 11) For the drainage line of the oil-water separator, ( ) type should be selected. 12) For pressure regulation of the container, if regulation is to be achieved by discharging material, ( ) type should be selected ； If adjustment is to be made using the incoming material, the ( ) formula should be selected. 13) For the outlet line of the distillation tower, the ( ) type should be selected. 14) For the reflux line of a distillation tower, the ( ) type should be selected. This post was last edited by Mobei Yihai on 2009-4-5 09:34.]
There are too many questions; I’m afraid I won’t be able to answer them all. 1. Air-shutoff type, to prevent the tank from being collapsed due to excessively low pressure inside it in the event of a fault. 2. Air-controlled shut-off, 3. Air-controlled shut-off; vents open in case of failure, 4. Air-controlled shut-off; vents open in case of failure to prevent overpressure in the drum, 5. Air-controlled shut-off; opens in case of failure to prevent water shortage in the boiler, 6. This should also be related to the process pipelines; air-controlled shut-off for the outlet and air-controlled opening for the inlet, 7. Opens in case of air-controlled shut-off failure to maintain liquid level, 8. Closes in case of air-controlled opening failure, 9. Cuts off fuel in case of air-controlled opening failure, 10. Cuts off feed in case of air-controlled opening failure, 11. Air-controlled opening (uncertain), 12. Air-controlled shut-off, air-controlled opening, 13. Air-controlled shut-off, 14. Air-controlled opening. Last edited by chmyh on 2009-4-5 10:38.]
1) The control valve at the compressor inlet should be of the (air-shut) type. 2) The compressor bypass control valve should be of the (air-operated shut-off) type. 3) For the compressor outlet pressure control system, when the control valve is installed on the vent line, a (air-operated shut-off) type should be selected. 4) The steam outlet control valve of the drum should be of the (air-operated shut-off) type. 5) The drum feedwater control valve should be a (air-operated) type with a right-mounted auxiliary positioner. 6) The control valve of the storage tank pressure regulation system should be of the (air-operated shut-off) type. 7) Storage tank level control system: when the control valve is installed on the inlet pipeline, a (air-operated) type should be selected. 8) Storage tank level control system: when the control valve is installed on the outlet pipeline, a (air-actuated) type should be selected. 9) The fuel oil system of the heating furnace should adopt a (air-operated) type. 10) The feeding system of the heating furnace should adopt a (air-shut) type. 11) For the drain line of the oil-water separator, a (air-actuated) type should be selected. 12) For pressure regulation of the container, if regulation is to be achieved by discharging material, a (air-controlled) type should be selected ； If adjustment is to be done using the incoming material, a (air-operated) type should be selected. 13) For the outlet line of the distillation tower, a (air-operated) type should be selected. 14) For the reflux line of the distillation tower, a (air-operated) type should be selected.
1. Air shut-off, 2. Air shut-off, 3. Air shut-off, 4. Air shut-off, 5. Air shut-off, 6. Air shut-off, 7. Air shut-off, 8. Air open, 9. Air open, 10. Air open, 11. Air open, 12. Air shut-off/Air open, 13. Air shut-off, 14. Air open
1) The control valve at the compressor inlet should be of the (air-shut) type. 2) The compressor bypass control valve should be of the (air-operated shut-off) type. 3) For the compressor outlet pressure control system, when the control valve is installed on the vent line, a (air-operated shut-off) type should be selected. 4) The steam outlet control valve of the drum should be of the (air-operated shut-off) type. 5) The drum feedwater control valve should be a (1-air-operated shut-off) type with a right-mounted auxiliary positioner. 6) The control valve of the storage tank pressure regulation system should be of the (air-operated shut-off) type. 7) Storage tank level control system: when the control valve is installed on the inlet pipeline, a (air-operated) type should be selected. 8) Storage tank level control system: when the control valve is installed on the outlet pipeline, a (air-operated) type should be selected. 9) The fuel oil system of the heating furnace should adopt a (air-operated) type. 10) The feeding system of the heating furnace should adopt a (air-operated) type. 11) For the drain line of the oil-water separator, a (air-actuated) type should be selected. 12) For pressure regulation of the container, if regulation is to be achieved by discharging material, a (air-controlled) type should be selected ； If adjustment is to be done using the incoming material, a (air-operated) type should be selected. 13) For the outlet line of the distillation tower, a (air-operated) type should be selected. 14) For the reflux line of the distillation tower, a (air-operated) type should be selected.
1. Air-off 2. Air-off 3. Air-off 4. Air-off 5. Air-off 6. Air-on 7. Air-off 8. Air-on 9. Air-on 10. Air-on 11. Air-on 12. Air-off 13. Air-off 14. Air-on
Each of the above answers has its own rationale, and they also reflect accumulated practical work experience; they should be quite comprehensive. However, one thing should be noted: these on/off conditions for the gas are not absolute; the process engineering team may have different requirements based on the characteristics of the process, and this is a situation that is often encountered in design work.
1) The control valve at the compressor inlet should be of the (air-shut) type. 2) The compressor bypass control valve should be of the (air-operated shut-off) type. 3) For the compressor outlet pressure control system, when the control valve is installed on the vent line, a (air-operated shut-off) type should be selected. 4) The steam outlet control valve of the drum should be of the (air-operated shut-off) type. 5) The drum feedwater control valve should be a (air-operated) type with a right-mounted auxiliary positioner. ? 6) The control valve of the storage tank pressure regulation system should be of the (air-shut or air-open type, depending on the process requirements) type. 7) Storage tank level control system: when the control valve is installed on the inlet pipeline, a (air-operated) type should be selected. 8) Storage tank level control system: when the control valve is installed on the outlet pipeline, a (air-actuated) type should be selected. 9) The fuel oil system of the heating furnace should adopt a (air-operated) type. 10) The feeding system of the heating furnace should adopt a (air-operated) type. 11) For the drain line of the oil-water separator, a (air-actuated) type should be selected. 12) For pressure regulation of the container, if regulation is to be achieved by discharging material, a (air-controlled) type should be selected ； If adjustment is to be done using the incoming material, a (air-operated) type should be selected. 13) For the outlet line of the distillation tower, a (air-operated) type should be selected. 14) For the reflux line of the distillation tower, a (air-operated) type should be selected.