Heat exchanger acceptance

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Let’s discuss some aspects of heat exchanger acceptance! 1. For the airtightness tests of all heat exchangers, both the tube side and the shell side are pressurized at the design pressure of the equipment, and the upper and lower tube sheets must be checked for leaks during the shell side pressure testing. 2. Disassemble the heat exchanger before pressure testing. After removing the upper end cap, the heat exchanger was placed vertically on the pressure testing fixture. A barrier 30 mm wide and 40 mm high was created around the flanges of the heat exchanger using wet dough; the tube side was filled with water to a level higher than that of the tube sheet, and compressed air was introduced from the shell side connections to conduct a shell side test. 3. Two pressure gauges must be used as references when charging the shell side. Once the pressure of the compressed air reaches the designed level, check for any leaks at the filling port and flange connections; if leaks are found, the construction party shall address them ； If not, close the inflation port to maintain pressure. Check from the horizontal plane of the upper tube sheet to see if any bubbles emerge; this process takes about 30 minutes. If no bubbles appear in the water and the pressure gauge shows no pressure loss, it indicates good airtightness ； If bubbles escape, it indicates a leak in the tube sheet weld or the tubes; all parties present should be notified to immediately mark the area and inspect for the leak. 4. If small bubbles continue to emerge from the inside of the pipe wall during pressurization, it is necessary to remove these bubbles before proceeding with the inspection. 5. After the inspection, if there is no leakage, relieve the pressure and drain the water, then turn the equipment over to test for leaks at the pipe sheet weld on the other end; follow steps 2 and 3 for the inspection process. 6. After both the upper and lower tube sheets have passed the pressure testing, the construction party shall clean the heat exchanger; the specific cleaning plan will be provided by the construction party. 7. Clean the heat exchanger (including the tube side, the interior of the head, various fittings, etc.; for heat exchangers where the process medium is exchanged with itself, the shell side is also included), ensuring it is dry, clean, oil-free, and rust-free. After passing the inspection, assemble it as a whole (check whether the gaskets used meet the technical requirements). Asbestos gaskets cannot be used; choose a PTFE gasket or a metal-wound gasket depending on the operating temperature. Next, perform pressure testing on the tube side: inflate the tube side connections to the design pressure (using two pressure gauges), and spray a foaming agent at the flange joints of the tube sheet for inspection. Observe for more than 20 minutes; if no bubbles appear, it is considered acceptable. 8. The gasket used for pressurizing the flange connection on the tube side of the heat exchanger can only be used once; if there is leakage at the sealing surface, the gasket must be replaced with a new one. 9. After the heat exchanger passes the inspection, seal all openings and fill it with N2 for protection. This post was last edited by hengjing on 2008-4-15 14:36]