The Ultraprobe allows valve activity, such as leakage or blockage, to be accurately checked while the valve is on-line. Properly seated valves are quiet, while leaking valves produce a turbulent flow - as the liquid or gas moves from the high pressure side through the leak to the low pressure side. Valve stems may be quickly tested for leaks to atmosphere.
Valve leak detection is actually a great application for the Ultraprobe. Using ultrasound is the only non-invasive method to use. Valves, which are assumed to be shut off tight, but are - in reality - passing, can be a safety critical issue for an operator.
The Ultraprobe operator takes readings and listens (through the headset supplied with the instrument) to each valve. It should be easy to establish a baseline, above which you know there is a problem. Estimating valve leakage can be difficult (but not by any means impossible) because there are so many variables which affect the turbulence (and therefore the ultrasound). For example: two valves may pass at similar rates. But because they have failed in a different way, the ultrasound readings are different. If the variables can be reduced, it should be possible to gauge the leakage on a Low-Mid-High scale.
Basically speaking: a valve which is shut off tightly should not add to the background level. A passing valve will not only sound different, but will produce a significantly higher dB reading on the instrument.
It is true that many of the valves we need to test produce a lot of internally generated ultrasound. If the operator simply listens to each valve, it is sometimes impossible to make a diagnosis. If you are utilising the Ultraprobe 2000, the solution is to use the sensitivity control and the meter. The Ultraprobe 9000 and Ultraprobe 10,000 makes this process a little easier, in that decibel readings are taken. These can then be downloaded to the supplied software if considered appropriate.
If you use the Ultraprobe 9000, you can decide whether to collect this data on a route basis (for example: you could enter locations for each of the valves, and record data from each one), or you could just take readings by exception (for example: if they were over a preset level). Furthermore, you could simply tag valves that were over a certain value and not bother to collect the data. The Ultraprobe 10,000, of course, has the added benefit that WAV files can be recorded at the time, and replayed and analysed using the supplied Spectralyser software.
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