Cartridge style counterbalance valves are used to control the movement of actuators, such as hydraulic cylinders and motors. Their main function is to provide load holding, and to control over-running loads, they also have relief protection should the actuator be over loaded higher than the pre-set pressure. Â Luen, thanks to a constant research and development, has launched its new overcentre valves, with the following technical improvements: excellent working stability; excellent sensitivity setting adjustment; pressure regulation without external leakage. Very often the cause of malfunctions in hydraulic systems and components is found to be excessive fluid contamination. In particular the hard and abrasive particles in the fluid wear the hydraulic components and prevent the poppets from re-seating, with consequent internal leakage and system inefficiency. For the correct operation of Luen valves it is necessary to ensure that the oil contamination level does not exceed the limits given in class 19/15 ISO-4406, or 10+11 NAS-1638, unless otherwise specified in the relevant technical sheet. Screw type, the cartridges can be fitted directly into the cavity in the actuator (cylinder, motor, pump, etc.) or in the integrated block. The valves are made of steel AVPB (9SMhPb28 or 32) or of Ng2Pb (16NCr4) for the internal mechanical blocks. All the internal parts are hardened and ground or lapped to ensure the maximum reliability and resistance. The external face is either zinc-plated (white) or burnished (black).
