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Lubrication pressure problem

Lubrication pressure problem

Lubrication pressure problem

Hi Guys

Please can you help with a hydraulic pressure problem?

We have installed a new lube system to a bearing; the bearing has no pressure seal and drains off by gravity.

The schematic given to us has a main pressure line which flows through a filter then flow restrictor then to the cooler and then to the bearing.

They state that main pressure line will run at 500KPA through the filter, flow restrictor and cooler and must drop to 100KPA.
Relief valve is set to 500KPA and to drop the pressure to the bearing to a 100KPA adjust the flow restrictor.

Do they determine the back pressure of 100KPA by the port size into the bearing or tube sizing to the bearing?
Example If you had a 2 " port with a 2" pipe flowing into the bearing and draining by gravity would you even get 100KPA assuming that the flow of oil through the 2" tube is very low?

At the moment the system runs at 500KPA but we are getting 80KPA with the flow restrictor fully open. We assume that we have a major pressure drop through the cooler cause pressure after the filter is around 450KPA unfortunately we did not do the piping to the cooler and bearing so there is only a gauge by the bearing. We have asked to install gauges on the cooler in and out.

If we adjust the relief valve pressure up we can achieve the required pressure but it is not to the schematic which is a problem.

Is the pressure to the bearing a safety system to show the DCS that there is no oil flow, or is it essential to have that pressure through the bearing?

Pump flow is 100LPM
Pipe size 1 ¼"


RE: Lubrication pressure problem

what type of bearing?  I'm familiar with babbit sleeved types.  the "bearing header" pressure is adjusted to 15 psig, but the feed hole at the bearing joint is orificed so that the oil in the bearing clearance is very little pressure when running.  I can "adjust" the flow to the bearing if running temperture indicates insufficient flow by drilling out the orifice with relative little change to the bearing header pressure   

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