pressure reduction
pressure reduction
(OP)
I want to get other people's opinion on this matter. Pump is pumping fluid at 150 psig discharge pressure and at 350 gpm. I will be intalling metal tubing (1/4") on 1" existing connection to send sample to online analyzer. We also want to add manual sample line for analyzer check. Peole are concerned about possible high pressure when techs opens a valve to take manual samples since it is hazardous chemical. Tubing will be ~ 30 ft long total and returned to suction of pump. It is continous flow through tube. My quick calc indicates there will be plenty of pressure drop through 1" tee and 1/4" tubing by the time it gets to the point people want to take samples. Installation of RO has been suggested to insure enough pressure drop. That seems to make people's feel better...rather than getting pressure drop through a long tubing. Will it be better to install RO to insure enough pressure drop for manual sampling?? Pressure regulator has been also mentioned....





RE: pressure reduction
When you first open the valve or an orifice, it would be at full pressure. When the line is static, there is NO pressure drop. Pressure won't drop until all the fluid in the tubing is moving. There can be a considerable acceleration of fluid near the end of the tubing as you open that valve, as basically that just depends on F = m * a
Forget the orifice plate. A finely controllable needle valve should be used, perhaps with a pressure regulator too. A pressure regulator will not let full pressure reach the valve, unless it is leaking across the seats when it is closed, also a possibility, in which case backup block valve and a blow off (junction located before the outlet valve) routed to a safe place may be necessary. How you want to handle that exactly depends on the toxicity of the fluid you're dealing with.
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: pressure reduction
RE: pressure reduction
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: pressure reduction
I've never seen anything other than a manual needle valve on a sampling system. If you just crack the valve, you will have only a very small amount of flow as there will be a large drop across the valve.
The valve manufacturers provide charts of the Cv vs. number of turns so you can find one appropriate to your system.
For a relatively high flow valve, you might consider a Swagelok N Series (Ball Tip Stem) or Parker U Series valve. For a low flow valve you might consider an Autoclave Engineers 10V Series valve.
RE: pressure reduction
If so, what is the pressure at the pump suction? Where along the loop do you want to put the sample point?
Notwithstanding that, the recommendations for needle valves are good advice, or use a sampling valve designed specifically for sample taking. Check this site for 'process valves.'
http://www.strahmanvalves.com/
rmw
RE: pressure reduction