Hydraulic Reservoir or Tank Size Calculation

Hydraulic Reservoir design and implementation is very important in hydraulic systems as the efficiency of a well-designed hydraulic circuit can be greatly reduced by poor tank design. In addition to fluid storage, a well-designed reservoir also dissipates heat, allows time for contamination to drop out of the fluid, and allows air bubbles to come to the surface and dissipate. It may give a positive pressure to the pump inlet and makes a convenient mounting place for the pump and its motor and valves.

The accepted rule for sizing a tank = (3 to 5) X Q
Where 'Q' is the pump discharge rate.
This will allow sufficient time for oil to cool down before recirculation into the circuit. Also, include one or two baffles inside the tank to increase the path of fluid for better cooling.

Also, you need to check the heat dissipation capacity of tank with above calculated sizes to make sure it is sufficient enough to cool down the oil.

Head Dissipation, HD = 0.001 x (T1 - T2) x A
Where
T1 = max. allowable fluid temperature (in degree F)
T2 = max. ambient air temperature (in degree F)
A = area of tank in contact with fluid (in sq. ft)

Heat dissipation is the main reason for having tank surfaces exposed to free air for better cooling.

I hope these two checks will be enough for a basic hydraulic tank design.

With best wishes,

Krish

Jythra Engineering Services