Yuken Relief Hydraulic Valve For Unloader

keyword:Hydraulic Remote Control Valve, unloading relief valves, pressure control valves

These unloading relief valves are used to operate the pumps with minimum load in accumulator circuits or in high-low pump circuits. In accumulator circuits, when the system pressure reaches to a cut out pressure (adjusted maximum), the valve acts to divert the pump delivery to the reservoir at low pressure, thus the pump is unloaded automatically. When the accumulator pressure drops to the cut in pressure (refer to characteristic chart on page 5), the valve directs the pump delivery to the accumulator and hydraulic system. An integral check valve prevents reverse flow through the valve from the accumulator. In high-low pump circuits, the valve acts to unload the large volume pump with the same manner as described above during load operation of the small volume pump.

●Recommended Viscosity and Oil Temperatures

Viscosity ranging between 15 - 400 mm2/s (77 - 1800 SSU).

Oil temperatures between -15/+700C (5 - 158°F).

Use hydraulic fluids which satisfy the recommended viscosity and oil temperatures given above.

●Control of Contamination

Due caution must be paid to maintaining control over contamination of the hydraulic fluids which may otherwise

lead to breakdowns and shorten the life of the valves. Please maintain the degree of contamination within NAS

1638-Grade 12. Use 25 µm or finer line filter.

■Instructions

●To adjust the pressure, loosen the lock nut and turn the pressure adjustment handle slowly clockwise for higher pressures or

anti-clockwise for lower pressures. After adjustments, do not forget to tighten the lock nut.

●Take care not to neglect connecting the drain pipe to the tank; otherwise not only will the valve fail to operate properly but

also the line pressure will rise infinitely.Extend the end of the drain pipe into fluid.

●Limit the pressure drop between the valve and the accumulator in an accumulator circuit below 10% of the

cut-out pressure.

●Limit the drain port back pressure below 2% of the   cut-out pressure.

BM2 hydraulic motors 

  One type of LSHT motor,shaft distribution flow with radial force bearing . 

BM2: