Construction issues with air separation instruments
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We have just installed an air separation unit here, and there are many pressure measurement points inside the cryogenic tank. Should the construction of the measurement piping from the measurement point inside the cold box to the valve frame section on the cold box wall be carried out by the piping specialty or by the instrumentation specialty? As I understand it, it should be carried out by pipeline specialists, because from the measurement point to the valve holder on the cold box wall, that section still belongs to the primary components. I would appreciate some guidance from those with experience. Thank you.
It should be carried out by the instrumentation team; when we carry out the work, everything behind the primary valve is handled by the instrumentation team
I agree with the view from the second floor: professional instrumentation (electrical and instrumentation) teams are needed to carry out the work. Additionally, the wires used should be special wires resistant to low temperatures. Also, the liquid sampling tube should have a liquid-sealing elbow or a dedicated heater. Prevent liquid from flowing outside the tower and causing vaporization, which could affect measurements and lead to loss of automatic control. When wiring/tubing, it is necessary to strictly follow relevant regulations and arrange the wire racks properly to prevent the wires in the racks from being damaged during the filling process. At the end of the bare cooling phase, it is necessary to enter the cryostat promptly to tighten the temperature sensors; for special devices, the flanges also need to be tightened to prevent leaks during operation at low temperatures.
It is better to have it constructed by the pipeline specialty, with the boundary point at the primary valve.
I also think it’s better to have pipeline professionals handle the work, with the boundary between instrumentation and pipelines being at the primary valve. The one-way valve is installed on the wall of the cold box. So the section from the measurement point to the primary valve should be constructed by the piping specialty. I have another question I’d like to ask. On the 4th floor, “the liquid sampling tube should have a liquid seal elbow”; should this liquid seal elbow be located inside or outside the cryostat?
The pressure guiding pipes for instruments inside the cold box need to be installed by the instrument installation personnel, while the pipes for the pressure taking valves should be welded in place.
The liquid-sealed elbow should be located near the sampling point； Now, all informal installation units require aluminum welding personnel to carry out the work, but it must be done in accordance with the instrument installation procedures. It is usually a turnkey project, followed by acceptance by the instrumentation and control personnel. All other non-aluminum welding installations are carried out by instrumentation personnel.
The aluminum piping is installed by professionals, and after it exits the tower wall, it is handled by the instrumentation team
The aluminum piping is installed by professionals, and after it exits the tower wall, it is handled by the instrumentation team