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  • Cooling jacket max operating pressure

    Hey all,

    About to do a pressure test on the new glycol lines and tanks. What limitations should I be concerned with here. I do not have any specs on the jacket rating so I will assume it to be 15 PSI - Standard no? - We have 6x15bbl Conical dual zone and 3x15bbl single zone Serving tanks.

    As well, difficulties are encountered with regards to calculating operating pressure ex chiller and in the lines as well as typical flow rates and pressure drop limits. Any help is much appreciated. Would I be safe to assume 3-5gpm flow rate? It is a closed loop system with a 40 gallon reservoir. I fear that this chiller is a high pressure one - how would I go about reducing it through the lines and especially before it gets into my jackets and blowin' them apart?

    Cheers,

    Conan
    Last edited by Conan; 03-06-2008, 05:36 AM.

  • #2
    Tanks are always 15 psi maximum unless stamped with an ASME "UV" (unfired pressure vessel) stamp. The jackets are another story. Although many manufacturers label their jackets as 15 psi maximum, that would pertain only to compressible gases ie:steam or CO2. Incompressible liquids like glycol/water often exceed this pressure in practice. I would perform a hydrostatic test on the tank and on the jackets. Fill the tank with water--NO AIR AT ALL--and slowly pressurize it to 1.5 times the maximum allowable working pressure (which should not be over 15 psi for an unstamped tank). Close the valve and ensure that the pressure remains unchanged at 22.5 psi for a few minutes. Repeat with each of the jackets, but you may wish to increase the pressure to around 30 psi to qualify the maximum working pressure at 20 psi. If the tank or the jackets fail, it will do so catastrophically ie:ripped welds. It's the price you pay to discover you have a crap tank.
    Regarding pressures and flowrates; they are interdependent. You may have a pump capable of high pressures, but to do so requires restriction. This restriction is dependent on what your line size is, piping materials, elbows & valves, jacket geometry etc. Figure that you should have a relief valve on the end of your glycol distribution loop so that if no fermenter solenoid valve is open, then you don't "deadhead" your pump. It will still circulate some liquid--albeit at a reduced flow and higher pressure. Practically, I set this valve to relieve to the return side at 15 psi. When cooling, this pressure reduces to around half that and this valve will remain closed. If you design your loop right, you won't blow anything apart. Good luck!
    Phillip Kelm--Palau Brewing Company Manager--

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