Double-layer oil tanks are used as metal pressure vessels for storing flammable and explosive oil. During and after the manufacturing process, the quality inspection of the double-layer oil tanks is an indispensable step.
1. Double-layer oil tank wall test: carry out a water filling test on the newly built or repaired oil tank, check whether the pressure vessel wall is tight, and perform visual inspection of the oil tank wall plate and weld.
2. Double-layer oil tank wall thickness inspection: materials must be inspected and stored in the warehouse when entering the site. The ground double-layer oil tank is mainly tested by ultrasonic, which is more efficient.
3, kerosene tightness inspection welds: kerosene has a very strong penetrating power, and kerosene is applied to the welds on the pressure vessel wall for tightness inspection. Remove dirt, apply white powder emulsion, and spray kerosene on the other side of the weld after drying. For example, after kerosene is sprayed at 12 o'clock (in the case of low temperature, the time can be extended), the surface of the white weld is free of spots, and the weld conforms to Claim.
4. Tank bottom detection: Magnetic flux leakage scanning technology detects the corrosion status of the tank bottom (such as corrosion depth and area, crack length, etc.). The detection principle of this instrument is: the magnetic flux leakage scanner detects the bottom of the oil tank. When the bottom of the oil tank is defective, the magnetic field distribution will change and the sensor can detect it. The disadvantage is that some areas will be missed and the bottom of the tank cannot be fully inspected. There is no debris and dryness at the bottom of the oil tank during testing. In addition, helium gas can also be injected into the bottom of the tank to detect leaks at the bottom of the tank.
5. Double-layer oil tank bottom plate weld inspection: When testing the bottom plate tightness by vacuum leak test, apply soapy water to the weld and cover the vacuum box for observation.
6. Leak detection is achieved by detecting the change in the volume of the oil in the double-layer oil tank. This method is not easy to find small leaks.
7. Measure the bottom pressure of the double-layer tank and calculate the weight of the medium in the pressure vessel for tank leak detection. If the quality continues to decrease, a leak has occurred.
8. Add dye to the water and check the leakage point by hydraulic test. In addition, you can listen to the sound on the tank wall or install a sound wave sensor on the tank wall, set up an observation well in the tank area to monitor, and use a dipstick to detect the tank liquid level for leak detection.
9. When the double-layer oil tank is receiving and dispatching, leak detection is carried out according to the difference of actual in and out volume.