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(Write this 6% down for your use in your size calculation).
A gauge / gage is a classic example of the "weight on a spring" principle.
Once the needles, plus rack and pinion, are excited into motion by a sudden pressure change, they will vibrate at their own natural frequency. To reduce the excitability, it is normal for a "choke" to be placed in the gage connection. This is often a needle or a screw with a flat place that removes the thread. These modifications are often referred to as "snubbers". Additionally, to stop the gage flickering, the casing around the bourdon tube and the mechanism, is often filled with glycerin.
All the above modifications, slow the response of the gage, and therefor prevent it from reading peak pressures on negative peak (valley) pressures, of short duration. So a gage will not read pressure pulsation.
If one is only interested in what the eye can see on a gage, and the eye can not see anything faster than 30 times per second /30Hz, then basically the decision has been made that there is no interest in knowing the level of pressure pulsation.
A gage shows the overall average pressure, and if you wish that to be an accurate display you may not wish to have the lag in gage response.
To ensure accuracy, and instrument life, a flow through pressure wave pulse interceptor may be used, and all forms of "snubbing" may then be removed.
Pressure (not flow) travels at say 3500 mph or 1400 meters per second.
Pressure wave pulsation therefor (EXCEPT SLOW RISE RATE SURGING, "INDUCED ACCELERATION HEAD" FROM FLOW FLUCTUATION) will be opposite to the 1/16" or 1.5mm opening into a gage for say 0.00001 seconds. If a gage can not react in less than 1/100th of a second at best, the gage can not detect any of the transient spikes and indicate to you that your system will suffer fatigue.
The use of good response characteristic transducers, with kilohertz data capture will enable recording of pressure pulsation, shock and the extent to which it is being dampened.
UNDERSTANDING FLOW OR PRESSURE PULSATION
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