求翻译：2.2 BHE换热器使用高压气体进行测试，有些大型号的换热器需试压至7.2Mpa，即使用至7.2Mpa后需进行更换气体，气体浪费现象严重。是什么意思？

2.2 bhe heat exchanger using high-pressure gas test, some models of heat exchangers are subject to pressure test 7.2mpa using to 7.2mpa the need for replacement of gas, gas, serious waste.

2.2 * BHE heat exchangers, use of high-pressure gas testing of some of the large heat exchangers for the pressure test to 7.2 to 7.2 , which uses Mpa Mpa required after replacement of gas, the gas wasting serious.

2.2 The BHE heat interchanger use compressed gas carries on the test, somewhat great model heat interchanger needs the hydrostatic testing to 7.2Mpa, namely must carry on the replacement gas the use after 7.2Mpa, the gas waste phenomenon is serious.

2.2 BHE heat exchanger using high pressure gas test, some type of heat exchanger pressure test you want to 7.2Mpa, that is used to 7.2Mpa need to be replaced after gas, gas waste seriously.