Process Equipment Update
For example, continuous flow traps should be discharging condensate continuously and an airborne ultrasonic analysis would expect to hear a modulating, continuous flow while infrared thermal inspection would indicate similar inlet and outlet temperatures. In the event of a blow-by condition,
the acoustics would change from a modulating flow to an intense, continuous rushing sound with variations in the thermal conditions. In the event of a plugged trap, the acoustics would be quiet and significant thermal differences would be recorded between the inlet and outlet temperatures. This indicates the potential challenges facing accurate diagnosis. The range of traps available, coupled
with the sheer size of many steam operations and the complexities of detection, mean that it is not uncommon for leaks to be missed or misdiagnosed. This may lead to faulty traps being left in operation and/or functioning traps being replaced. The net result is the same: more lost energy and more unnecessary expense.
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programme with a clearly defined schedule of steam trap survey routes – ideally on a quarterly basis. The routes would be generated in the site’s CMMS and be scheduled weekly. In summary, steam leakage can have
serious implications for industry in terms of financial and machine performance
he sensitivity of most high frequency monitoring equipment allows the testing person to hear not only completely failed steam traps (blowing steam), but even leaking steam from a trap in operation.
Surprisingly, perhaps, there is no commonly accepted model to address this challenge, but there are definite moves towards establishing strong and effective processes. While undertaking any form of survey is good, a best practice approach may be to take a more aggressive stance. In other words, rather than seeking
to track down faulty leaks once they’ve happened, look to prevent them in the first place. Rather like insulating a loft to eliminate heat loss, such a commitment would deliver continuous and long-term return on investment. The key to this would be the introduction of a planned
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and health and safety risk. A proactive steam trap programme included within a steam system management programme has a huge impact on lowering energy costs, through identifying defective steam traps and calculating the loss each can be causing. A planned and preventative maintenance programme can mitigate against these damaging effects, but to be truly effective it should be performed with a suite of technologies – visual, thermal and ultrasonic – and undertaken by experienced personnel. Under such a regime, significant long- term benefits can be achieved. n
Steam leaks can occur in many places, including valve stems, pressure regulators and connection flanges pipe joints.
Hans de Kegel is with AVT Reliability, in Handforth, Cheshire, UK.
www.avtreliability.com
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