Valve failure timely and accurate disclosure of the petrochemical industry found safe and efficient production is essential. The existing copper check valve testing methods also are relatively simple, such as the overall valve disassembly and inspection and maintenance, and this valve testing technology not only affect the normal operation of the production, but also because of the valve in a long time and no routine maintenance risks implicit case. The valve line detection technology for its outstanding advantages: very effectively detect the presence or absence of valve leakage and the location and extent of the leak leaked makes this technology will inevitably replace the whole valve disassembly and become the focus of corporate attention. Now on-line detection of the free standing electric oven which the two methods are analyzed and discussed: acoustic emission method and the negative pressure wave method.

Acoustic emission, also called stress wave emission is localized source material release energy quickly produce a transient phenomenon of elastic waves. When the valve seal due to poor performance can be tested, because ejected from the sealing surface of the medium to form a sealing surface elastic wave turbulence, which was leaked elastic wave acoustic emission signals. This traffic signal strength and fluid velocity, before the valve pressure differential pressure valve, piping and other factors. When once this elastic wave signal is transmitted to the surface of the material, acoustic emission detector will detect this signal, to turn them into electrical signals and amplified and processed, thus achieving the goal line detection valve leak. Advantages of acoustic emission line detection method is its high sensitivity, without removing the free standing gas stoves, convenient, and can be used in inaccessible valves.