Installation And Construction Steps of Large Oil Tank

The construction process of the oil tank installation is as follows: foundation construction and acceptance → prefabrication → Assembly and welding of the tank bottom plate → installation of the top ring wall plate, assembly and welding of the tank top → installation of the electric hoist in the tank → flip of the remaining rings of the tank wall plate in turn → installation of the bottom panel → removal of the electric hoist → welding of the fillet weld between the bottom plate and the wall plate → Welding of the bottom plate and the butt weld of the edge plate → water test.

1. Foundation construction and acceptance

Before tank assembly, retest and check the tank foundation of civil construction handover according to the drawings, release the vertical and horizontal lines and mark the elevation points, and set the foundation settlement observation point and determine its elevation. According to the site conditions, the foundation construction process is as follows: fine sand cushion backfill → coarse sand layer laying → asphalt sand laying. The thickness of each layer of sand layer is 200mm, and it is rammed by frog rammer after raking. The volume proportion of asphalt in asphalt mortar is 8%-12%. A 100mm thick cushion layer is provided under the asphalt mortar cushion layer of the tank foundation. After the foundation construction and maintenance, draw a cross line on the foundation, and draw the bottom edge line according to the line. The elevation deviation, the height difference on the circumference of the supporting tank wall, and the height difference on the same circumference of the asphalt sand layer shall not be greater than the specified value, and the surface of the asphalt sand layer shall be dense without penetration cracks.

2. Assemble and weld tank bottom plate

According to the drawing of tank bottom plate, the tank bottom edge plate and the middle plate are divided, and the material plate is processed and numbered in sequence. The position line of each bottom plate is drawn on the basis, and the bottom plate should be sandblasted and painted with asphalt paint before the bottom of the tank is laid, and then the bottom of the tank is laid. The edge plate is laid according to the design drawing first, and the middle web is laid one by one from all sides.

After the bottom of the tank is laid, the edge plate is fixed by spot welding, and then the manual arc welding is started. The welding is carried out in strict accordance with the welding process regulations.

3. Install top ring siding

After the bottom of the tank is welded, install the top ring wall plate according to the plate layout. After the top ring panel is installed, ensure the verticality, ellipticity and upper level of the panel. After the verticality, ellipticity and upper level of the panel are adjusted, the panel is temporarily fixed, and three anti-deformation arc plates are installed on the longitudinal seam of the panel to prevent welding deformation. The outer longitudinal seam can be welded first, and the inner longitudinal seam can be cleaned, and then the inner longitudinal seam can be welded, and the inner longitudinal seam can be polished until it is flush with the base material and inspected according to the design requirements and specifications. After the top ring wall plate is installed and checked, install the wrapping Angle steel. The joint of the wrapping Angle steel and the longitudinal joint of the wall plate should be staggered by more than 200mm.

4. Assemble and weld the roof

The roof of the tank shall be installed after the top ring wall plate passes the inspection, and the umbrella stand shall be set before installation. The height of the umbrella stand shall be determined by calculation. The upper surface of the umbrella stand shall be ensured its levelness, and another ring beam shall be set between the umbrella stand and the Angle steel with the edge, and the upper surface of the ring beam shall be checked with a level. In addition, a window is reserved in the top plate at the upper end of the flip column to be closed after the tank is installed to ensure ventilation during installation.

5. Tank lifting installation

5.1 After the top of the tank is installed, install the electric hoist lifting device.

5.2 The expansion ring is installed at the lower end of each ring tank wall about 100mm, so that the expansion ring and the tank wall form an integrated force. The lifting lug is welded on the expansion ring, and an electric hoist is used to control the lifting device to lift the wall of the tank through the lifting lug and the expansion ring.

5.3 After the lifting device and expansion ring are installed, wrap the second ring of wall panel, set up the spot welding longitudinal seam, reserve 1 longitudinal seam not spot welding. After the outside of the longitudinal seam is welded, you can begin to lift the top ring tank wall.

5.4 Before lifting, check whether the expansion ring is tight, whether the gantry clamp is welded firmly, whether the flip column is reliable, and then start lifting after determining the lifting device is correct.

5.5 Start all the electric hoists again to raise the tank body in place, tighten the live mouth with two hand hoists, measure the circumference, cut the excess wall panel, polish the groove and spot welding, and make the upper end of the lower ring wall panel close to the tank wall damper, the lower end close to the tank bottom inner damper, adjust the local place that is not in place, adjust the ring gap with electric hoists, and perform group spot welding and welding.

5.6 Install the third ring plate on the outside of the second ring panel, and after the coaming plate and the pair spot welding is completed, weld the longitudinal seam. After the longitudinal seam is welded, repeat the above inspection, lift the second ring panel, seal the longitudinal seam on the third ring, and then the ring seam between the second and third ring. After the group is welded, the expansion ring is lowered after welding, and the expansion ring is installed to the lower opening of the third ring wall panel. Repeat the process until the tank walls are fully installed. When installing the last ring wall panel, leave the vertical seam of one plate unwelded. After the ring seam group is matched, open the door here, remove the flip device in the tank, and then seal the door and weld.