These valves provide thermal protection. Loads can be controlled, lowered or braked if a directional control valve with an open centre position is used. Counterbalance valves can be used to improve the control of almost all drives, as these loads become positive loads from the point of view of the directional control valve, even if the load itself is pulling on the motor (negative load).
Due to the inverse upward control ratio, light loads are brought down with high control pressures. Heavy loads, on the other hand, are brought down with lower control pressures. This makes the loads more controllable and improves the stability of the entire drive.
This makes the loads easier to control and improves the stability of the entire drive.
At a load pressure of 85 % of the opening pressure, the leakage of new valves is a maximum of 0.35 ccm/minute.
Good tolerance to oil contamination.
Works reliably with both hot and cold oil.
Up to 350 bar
Up to 480 l/min
The opening pressure of the valve can be set using an adjusting screw.
The built-in non-return valve is available with different preloads (2 bar is recommended for protection against shock loads and 0.3 bar for protection against cavitation).
Most valves have a small leakage behind the control spool, which serves to bleed the control line and improve hydraulic actuator stability.
Available with control ratios of 3:1, 4.5:1, 1:1, 5:1, 2:1 and 10:1
SUN Retention Valves offer numerous advantages such as improved system safety, simplified control, reduced leakage points, reduced pipework costs, space and weight reduction, simplified maintenance and reduced installation time.