59，assembly of inner and outer cylinders of storage tank -威尼斯2299

assembly of inner and outer tanks

before the assembly of the inner cylinder of the storage tank, the longitudinal tie plate on the outer surface of the inner cylinder shall be heated and dried with flame for assembly.

preparation before assembly of outer cylinder section

1) assemble the transverse lower tension belt, ensure the geometric dimension of the lower tension belt, and wind it as required

2) assemble the horizontal upward tension belt, wind the glass fiber cloth as required, loosen the upward bolt to ensure the assembly space of the inner cylinder, fix the tooling on the upper process hole, and use the upper process hole to ensure the smooth connection of the horizontal upward tension belt after the assembly of the inner and outer cylinder.

inner and outer cylinder assembly

1) the assembly direction is that the head on the left side of the inner and outer cylinder enters from the right side of the outer cylinder.

2) the lifting lug is welded on both sides of the inner cylinder head, and two lug supports for tooling are welded on the right head.

3) the trolley traveling plate is placed under the assembly trolley, and an assembly trolley is placed near the right lateral pull-down belt in the middle of the outer cylinder. the trolley height ensures that the inner cylinder can pass through the lateral pull-down belt.

4) assemble the head and longitudinal tension strap, and weld them by manual arc welding. connect and fix the transverse upper tension band, and assemble and weld the process hole of the transverse upper tension band.

assembly of outer head and cylinder

1) the left head is assembled with the cylinder body, the mixed gas shielded welding is used to fix the joint, the mixed gas shielded welding is used to seal the bottom, then another layer is welded, and the surface is submerged arc welded.

2) the stainless steel pipe is led out from the transition pipe. the weld between the cylinder and the head is fixed by mixed gas shielded welding. after the bottom is sealed by mixed gas shielded welding, another layer is welded and the surface is submerged arc welded.

3) the transition pipe is assembled with stainless steel pipe and welded by argon arc welding.

4) 100% ultrasonic flaw detection shall be conducted for the weld between cylinder and head, and the grade i is qualified.

sandwich air tightness test

1) at present, the pressure of the inner cylinder is raised to 0.1mpa with nitrogen, and then the pressure of the interlayer is raised to 0.2mpa with nitrogen, and the pressure is maintained for 30 minutes without leakage.

2) release the interlayer gas after it is qualified.

sandwich helium leak detection

1) connect the vacuum valve. first, use a large flow pump to initially vacuum the interlayer. when the vacuum degree reaches 100mpa, replace it with a 70 rotary vane vacuum pump to pump the vacuum degree to about 1pa. close the vacuum valve, connect the helium leak detector, and start the helium leak detector. after the vacuum degree of the helium leak detector reaches the required value, open the vacuum valve to detect the leakage of the inner cylinder.

2) all longitudinal girth welds of the outer cylinder and the welds between the cylinder and the transition joint shall be subject to helium leak detection.