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57,Helium leak detection and gas pressure test for inner cylinder of storage tank - Doer equipment

Classification:Industry PublishTime:2019-09-27 14:37:17

Helium leak detection and air pressure test for inner cylinder of storage tank


Assembly of tank shell and head


1) The right head is assembled with the cylinder, the outer side is fixed by manual arc welding, the inner side is welded by manual arc welding, the outer side is gouged by carbon arc air gouging, and the metal luster is polished by grinding wheel, and the outer side is welded by submerged arc welding.


2) The welds of right head and cylinder are qualified by 100% X-ray flaw detection.


3) The internal connecting pipe and transition joint of the cylinder are assembled and fixed by argon arc welding and welded by argon arc welding.


4) Clean the inside and degrease the part.


5) The left head is assembled with the cylinder, the root is fixed by argon arc welding, the root is sealed by argon arc welding, then one layer is welded by argon arc welding, and one layer is welded by submerged arc welding with low current, and the surface is welded by submerged arc welding with normal current.


6) The welding seams of left head and cylinder are qualified by 100% radiographic inspection.


7) The inner pipe and the cylinder are assembled and welded by argon arc welding.


8) Assembly welding adsorption device, argon arc welding.


9) The longitudinal tie plate and tie bar are assembled and welded. When welding the base plate, there is a 20 mm non welding area on the left side.


Air pressure test of inner cylinder


1) Weld the stainless steel pipe orifice, leave the liquid discharge pipe orifice to connect with the air pressure test tooling.


2) The liquid nitrogen is pumped into the vaporizer by a pipeline pump in a low-temperature storage tank to make the liquid nitrogen into a gaseous state. The pressure reaches 2.31mpa and the pressure is maintained for 30 minutes.


3) Release the gas after the air pressure test is qualified.


Helium leak detection of inner cylinder


1) Cut off the air pressure test tooling, weld the vacuumizing tooling, connect the vacuum valve, first use the large flow pump to initially vacuumize the inner cylinder. After the vacuum degree reaches within 100Pa, replace it with 70 rotary vane vacuum pump, pump the vacuum degree to about 1pA, close the vacuum valve, connect the helium leak detector, and start the helium leak detector to make the vacuum degree of the helium leak detector reach the required value, Open the vacuum valve to detect the leakage of the inner cylinder.


2) All longitudinal girth welds of inner cylinder, welds between cylinder and transition joint, and butt welds of pipe shall be inspected by helium gas.



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