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APPLICATION OF ACOUSTIC CONTROL TO STEAM TRAPS CONTROL & REGULATION

What control? Why?

The steam traps control and the regulation offers a considerable improvement of a power plant efficiency and security. A steam trap blocked in closed position can lead to water hammers. Water Hammer can cause pipelines to break, a dangerous situation to workers nearby.

However, the steam traps control is useless without the bypass tightness control by Acoustic Method (checking procedure by ΔT° upstream / downstream not efficient). A leaking bypass evacuates condensates and steam without distinction, what makes useless the replacement or the regulation of the associated steam trap.

MMC’s method allows controling the steam trap, his bypass and isolating valves as a complete set.

MMC’s acoustic method, validated and applied in the majority of nuclear power plants, has the advantage to control the steam trap directly and to show by curves its opening and closure cycle, its regularity, as well as to see if it closes completely or if it is permanently opened.

This method also allows determining with exactness if the steam trap bypass is tight.

The acoustic method is the most adapted to the steam traps control because it has no constraint bound to the thermal inertia provoked by steam trap openings and closures. Furthermore she allows the direct visualization of the steam trap openings and closures curves, the recording, the filing and the steam trap curves follow-up.

A steam trap working properly offers a better output from your plant.

> Click here to learn how does it work...

Principle of the MMC’s Method:

1st Step :
We select a significative frequency.

2nd Step :
Configuration:

By-pass: Upstream Valve: Downstream Valve: Trap:
Closed Open Open Ready to work

3rd Step:
We recorded the trap cycle during a 120 sec. period at the significant frequency.

4th Step:
We close upstream and downstream valves.

5th Step:
The steam trap is isolated, we can now record his background noise

6th Step:
We test the by-pass valve tightness with the differential method. This method can eliminate all crosstalk noises.

Failing Trap :

mauvais purgeur

Analysis:

The black signature is a record of the normal trap cycle, we can see his cycle on the picture (Ascent and descent), and the red curve is a record of his background noise. This steam trap has a problem, his cycle is irregular and we can notice that it doesn’t close completely. It is leaking; we can compare it to a opened valve.

Leak severity : medium leak : 18dB ( Pressure amplitude: 37 dB Background: 19 dB). The by-pass valve has been tested with the differential method, it’s tight.


Good Working :

bon purgeur

Analysis:

The black signature is a record of the normal trap cycle, we can see his cycle on the picture (perfect ascent and descent), and the red curve is a record of his background noise. This steam trap is well working, his cycle is regular and we can notice that it is completely tight during his descent; because his pressure noise (24dB) is equal to his background noise (24db). The by-pass valve has been tested with the differential method, it is tight.



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