Tank hydrostatic test before tank construction

Hydrostatic test of inner tank before tank construction

(a) Conditions to be met before hydrostatic test of inner tank:

◇ all welding and NDT of the inner tank have been completed, and the corner welding of the bottom plate and wall plate of the inner tank has passed the vacuum box inspection. The bottom of the inner pipe shall be thoroughly cleaned.

◇ all measuring points have been set (8 measuring points on the outer wall of bearing platform and inner tank respectively).

◇ the pump strut passes the pressure test, the bottom pipe orifice is closed, and the tank top pipe orifice is well covered.

◇ all inlet pipes have been connected, all top nozzles have been opened, and the production of water level display setting has been completed.

◇ two submersible pumps are fixed at the bottom of the inner tank, and the temporary pipeline installation is completed.

◇ the check valve installed at the bottom of the nozzle is installed.

◇ the water for hydrostatic test of inner tank shall be clean, free of particles and odor:

(b) Inner tank water injection

(c) Inspection contents of hydrostatic test

◇ visually check for leakage and deformation

◇ stop water filling when the inner tank is filled to 300mm. Visually check that there is no water leakage at the weld at the tank bottom. If water leakage is found, drain the water immediately and repair it. After the repair, a new vacuum chamber test shall be conducted, and the repaired welding parts shall be recorded. When the water level reaches the required water level, the water injection shall be stopped and the settlement observation record shall be made 30 minutes later. During the water injection, the welds on the tank wall shall be visually inspected for water leakage and deformation. If leakage is found, the liquid level shall be reduced to less than 300mm below the leakage part for repair. NDT shall be conducted immediately after repair, and water injection shall be continued after passing the inspection. It is qualified if all welds are free of leakage and the tank body is free of abnormal deformation after water filling.

◇ during the hydrostatic test, the pump support pipe shall also be inspected visually, especially whether the pipe orifice is deformed. At the same time, check whether the perlite concrete at the bottom of the inner tank is broken, crushed and expanded.

◇ when the liquid level reaches all inspection liquid levels, the settlement record shall be recorded, and the settlement value shall not exceed the following table:

Note: if the inclination exceeds 25% of the acceptable value or the settlement exceeds 50% of the acceptable value, the irrigation must be stopped and the value reported to the owner for treatment opinions.

When the water level reaches the above four levels, it needs static load for 24 hours to observe settlement and inclination.

In the process of water injection, knock the anchor belt plate with a small hammer every 4 hours to avoid stress on the anchor belt Doer  to too small gap.

(d) Closure of outer tank wall plate

After the inner tank passes the hydrostatic test, block the door plate of the outer tank and remove the supporting angle steel.