1. Requirements for self inspection and positioning of tooling

1. The pneumatic quick plug joint automatically locks the heat exchanger tube mouth, and the empty load automatic fixture air tightness self-test is carried out. The joint seal leakage is directly alarmed by sound and light, and upper part inspection is prohibited.

2. The fixture is compatible with multiple heat exchanger specifications and can be quickly changed; Soft sealed structure shall not crush aluminum flat pipes, plates, or pipe mouth welds, causing artificial leakage.

3. Large shell and tube heat exchangers are equipped with lifting and positioning mechanisms to ensure the sealing and fitting of the chamber.

2. Pipeline blockage and blowing test

Low pressure dry clean nitrogen purging of the tube/shell side, detecting welding blockages, aluminum shavings, and bent blockages; If the flow channel is blocked, it will be judged as NG and the helium detection process will be skipped.

3. Nitrogen pressure resistance+pressure attenuation rough leak detection

1. Pressurization rules: The test pressure is taken as 1.5 times the rated working pressure. The automotive air conditioning heat exchanger is 2.5-3.43MPa, the industrial plate heat exchanger is 0.8-2.0MPa, and the shell and tube pressure heat exchanger is executed according to GB150.

2. Keep the pressure for 3-5 minutes, monitor the pressure drop in real time, and if the pressure drop exceeds the standard, it will be judged as bursting of the pipe or major cracking of the weld seam. The equipment will automatically release pressure and be judged as unqualified, and will not enter high-precision helium testing.

3. Appearance verification: There are no bulges, deformations, or plate protrusions throughout the entire process, and the basic structural strength verification is completed synchronously.

4. Pre testing of internal cavity cleanliness

After blowing, the impurities in the inner cavity are ≤ 20mg/㎡, the particle size is ≤ 0.5mm, and the residual water meets the standard to avoid refrigeration ice blockage and coolant pipeline wear.