大型U型管式热交换器在运行期间存在漏点，为了对微小漏点进行准确定位，采用正压吸氦法进行检漏。由于开放式的热交换器存在氦气本底污染的问题，所以研发了一种“橡胶塞和覆塑料薄膜”相结合的方法，对U形管式热交换器的管束和胀接焊缝分别进行氦气检漏，该方法能精确定位到泄漏的传热管，并缩短氦检漏的检查周期。

There often occurs leakage point in large U-tube heat exchanger during its operation. In order to locate the small leakage point accurately, positive pressure helium absorption method is used to detect the leakage. There exist the problem of background helium pollution for the open type of heat exchanger. The method of rubber plug combination with plastic film is developed to carry out helium leak detection on the tube bundle and expansion weld of U-tube heat exchanger respectively. This method can accurately locate the leaking heat transfer tube and shorten the inspection cycle of helium leak detection.