Reservoir Considerations

[horsefeather]

My new units need a hydraulic reservoir. The reservoir is mounted on the back of a tractor (truck) along with all my pumps. Hoses on a swivel hose carrier run between the resevoir and the trailer where the actuators are.

The size of the resevoir is about 350 gallons. This was selected by the total amount of fluid in the system, expansion due to heat and the amount of time before the operator spots a leak. There will be a sight gauge on the side and a temperature sensor.

The reservoir is vented and I'm asking for a tapered bottom that leads to an outlet tied to an onboard kidney loop. I'm thinking that slightly above the taper will be the pump/replenishment suctions and near the top will be the returns and drains. This is being designed by real hydraulic engineers whom I will visit next week.

I'm thinking there will be a baffle plate of some sort in the ullage to reduce slosh that will extend below the nominal surface to a reasonable depth.

I accepted their recommendation not to have suction strainers due to their inaccessability and danger when blocked, but after thinking about for a while I decided to put one in. Not because I think there will be a problem but because every system I've seen has one and I don't want a future engineer making fun of me for not having one.

Any tips considering reservoir design I should consider before I meet with the designers next week? Does anyone have luck with plastic or aluminum construction?

 

[budt]

Vickers, I believe, sells Suction Strainers that mount externally and act as a Right Angle (Elbow) for Inlet to the pump. No Problem changing elements, even has a TellTale indicator as an option.

Can protect a pump from large debris that will stop them fast. Not cheap though.

Don't forget Clean Out Covers so the tank can be serviced when something comes apart and fills it with trash, or just for servicing when changing oil.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[IceStationZebra]

If you are worried about servicing the suction strainers you might also consider strainers that screw into a large pipe bung in the reservoir. See this example

http://www.hydacusa.com/valves/suction_strainer.htm

Almost everything I have worked on in the off-road sector has had a suction strainer - with the usual explanation that it will keep an errant nut from ruining a pump. One thing to watch out for is pump inlet restriction with cold oil - pumps don't like to cavitate.

Bud - if you are curious I had a supplier change the size of the holes in the inner support tube from 5 to 8mm and it made a big difference below ~15°F.

ISZ

ISZ

 

[chief]

Hydraulic systems I am familiar with , normally have the filter on the return leg to the reservoir.,because of its relativelly low pressure obviously. The oil top up inlet has a mesh screen and the pump suction also has a coarse mesh screen Y-filter. A fine micron type filter on the suction of the pump, could cause pump problems if it chokes.

Offshore Engineering&Design

 

[hydtools]

Make sure the returns to the tank exit below the fluid level to prevent mixing air into the fluid. The baffle should separate the pump suction from the tank return to prevent direct flow from return to suction.

I would not worry much about having a temp sensor in the sight gage. It would be better to have a temp sensor in the center of the tank or sensing the interior or return flow temp of the fluid.

Like chief said, a return filter or filters should be used. They should have bypass valves to bypass flow if you have cold startups instead of overpressuring the filters when the fluid is cold and thick.

Include cleanout access to the tank.

Ted