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Davedplumb
24-07-2016, 04:07 AM
I'm having trouble finding any information on why it's best practice to have a regulating valve on the return of a water oil cooling system for a screw compressor?

RANGER1
24-07-2016, 10:41 AM
I'm having trouble finding any information on why it's best practice to have a regulating valve on the return of a water oil cooling system for a screw compressor?

We would install a Saunders water flow valve in return line of each oil cooler for any required water flow adjustments.
They can be used to adjust water flow, mainly for seasonal temperature adjustment to maintain correct oil temperatures.
Other alternatives is to install 3 way AMOT type thermostatic valve.
Oil is bypassed around cooler to maintain correct oil temperature with no need for adjustment of any water flows.

Davedplumb
24-07-2016, 10:55 AM
Thanks for that, but why on the return line is it easier to control than installing it on the flow

NH3LVR
24-07-2016, 03:39 PM
One answer is that if it is on the return line the heat exchanger will not empty during off periods.
If it drains and dries out it encourages scale buildup.

RANGER1
24-07-2016, 08:44 PM
It would work either way as long as situation that NH3LVR describes did not happen.
Most applications water in & out comes from above heat exchanger.
If you looked up Danfoss water cooled condenser head pressure control valve. they also suggest put control valve on exit flow.
If water flow is low for long periods, fouling can occur in some cases as sediment can drop out.

Also if you have separate cooling tower you could control fan with VSD to control sump temperature.

Tycho
25-07-2016, 04:32 PM
Thanks for that, but why on the return line is it easier to control than installing it on the flow


The regulating valve will do the same job no matter what side of the oil cooler you install it...

However, if you install a flow restriction on the inlet side there will be massive cavitation on the inlet/outlet divider if it is a 2-pass oilcooler, and on the first few inches of the pipes on the inlet side.

When it comes to watercooled oilcoolers, personally I prefer full waterflow and using a three-way mixing valve on the oil side for a more stable oil temperature :)

But installing any restriction on the water inlet is a no-no for any tube/shell coolers