Restrictor Check Valve - Fig. WH 220
(5) Cap nut
The restrictor check valve is a combination of an adjustable restrictor and a check valve. It helps prevent stick "flopping".
Depending on the position of spindle (4), the pressure oil is throttled, more or less, in one direction.
The oil flow thereby reaches the rear side of the cone (3) and passes through lateral bores to the restrictor point formed between the cone (3) and the spindle (4).
In the opposite direction, the oil acts upon the front face of the cone (3). This is raised from its seat, and oil flows to the valve unrestricted.
This restrictor check valve is built into the pressure line on the rod side of the stick cylinder.
Make sure the valve is installed in the proper direction. The pressurized oil must flow to the cylinder unrestricted, while the discharged oil flows back through the adjustable restrictor.
Installation of the restrictor check valve is to prevent the cylinder from extending faster than the oil entering on the opposite side can refill the cylinder volume, on account of the load.
Turning the spindle (4) in will produce a reduction of cylinder speed.
Do not close the restrictor check valve excessively because there will be a possibility of the hydraulic oil being overheated and causing damage to the system.
Turn the spindle clockwise to slow the stick speed. Turn counterclockwise to increase.