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6th July 2007 - 02:31 PM
I'm new here and have some fluids training (1 Fluids course in college while getting my Electrical Engineering degree in the 60's). I don't have a grip on whats available (today's hardware) regarding fluid control that are reasonable in cost to the average consumer.
Here's my problem. I'd like to take street water pressure (75-150 psi) and reduce it proportionally and then use a pressure switch to indicate when the pressure (by ratio) is too low.
The reason for the proportional approach is that the cost of pressure switches over 60 psi or so are quite expensive. So my thinking is to ratio it down then use the standard water pump pressure switches (under $30) as the sensing unit.
What I can't recall (and use the one semester of Fluids) if a standard water shut off valve can be adjusted to do the job (statically). I remember something about areas, pressures and velocities being related (Mr. Bernoulli) but in real life I don't have a strong fluids background to know if this is actually a way to go.
Thanks in advance for any thoughts and suggestions.
6th July 2007 - 07:02 PM
This is a followup on some raw data.
One water load (8 "almost equal" items for this particular water load) was working normally and was at 100 psi at the water feed point. When one of the items was removed and that port was completely open, the pressure dropped to about 70psi at the feed point.
I'm guessing the geometry of distribution system is playing into the readings since I expected about a 13% (1/8) drop or about 86-88 psi.
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