I just found this particular forum by accident, even though I have been using eng-tips for several months.
I have a "disagreement" with some colleagues.
We have a 27,000 gallon liquid nitrogen tank. As part of a test I pressurized it to 70 psig, opened the drain valve and monitored the...
I have gathered a couple of things from this forum, as well as from reading.
Deadheading or low flow - BAD
High flow to the right of BEP - BAD
Ashcroft makes a differential pressure switch with 2 independently adjustable setpoints. I am thinking of using such a device on a transfer pump. I...
By measuring wet and dry bulb temperatures you are, in effect, calculating relative humidity. Evaporative coolers work much better in dry climates. When I lived in New Mexico there was one in my apartment instead of an air conditioner.
Sounds like a job for those crews that come in with shaped charges, detonator cord, etc. Is it called implosive demolition? I've seen pictures of buildings that fall in on themselves with minimal disturbance to nearby structures.
Thanks for the insights. I had not thought about the pulsations. What makes this proposal more interesting is the fact that the fluid will be liquid nitrogen and the flow rate will be somewhere in the neighborhood of 25 GPM. The downstream vaporizer will not handle much higher flow.
Does a variable speed centrifugal pump make sense as a booster for a reciprocating pump? I believe some of my colleagues are proposing such a system. Perhaps they think that a control valve and return line are unnecessary, or they believe the centrifugal pump can be made to operate close to its...
If memory serves me right, the 3-phase GFCI units are rated as ground fault protection for equipment. The trip levels may be higher (~30 mA??). The single-phase units are probably rated as ground fault protection for personnel (4-6 mA trip level). A look at the data sheets might clear things up.
Has anyone heard of companies that make pulsation dampeners for cryogenic service? We may have a problem with acceleration head on the suction side of our reciprocating pumps.Thanks for any help or insight.
I was discussing the problem of deadheading, BEP, etc., with a colleague. This person was of the opinion that pumps should be started/stopped unloaded.
I think I have seen some good advice from this forum. Any thoughts on the paragraph above? Agree or disagree?
We have been running a lot of centrifugal pumps (liquid nitrogen service) through the repair shop. I began reading up on centrifugal pumps and discovered the BEP (best efficiency point). I also learned how a pump can be damaged if one strays too far to either side of this point. Here are a...
We are using desiccant dryers/scrubbers downstream of some high-pressure (2500-3000 psig) air compressors. Because the air pressures are so high, we use synthetic cylinder lubricant. We had an episode where oil was carried through the dryer, but it was only discovered by doing a condensible...
I read about a contractor who built a house in Florida and was faced with a similar problem. One of the walls was mostly glass. Since he couldn't do a shear wall, he built a steel moment frame and attached wood nailers so that it could be easily covered and blended into the remaining structure.
McCrometer makes a V-cone flow meter. It is a differential type that has a cone placed in the flow stream. This helps to condition the flow, so the flow meter does not require a lot of straight piping upstream/downstream.
You mentioned using ball valves for the control valves. I understand that ordinary ball valves are great for on-off service, but lousy for modulating service. I think I remember seeing ball valves that are designed for modulation.
