Load sensing control block SPV 120

Product description

SPV 120 is a proportional load-sensing control block in sectional design, suitable for a wide range of applications such as mobile cranes, excavators and municipal vehicles.the load-sensing control block consists of three main components: input plate, directional valve sections and an end plate. The valve is available in versions for open center systems with a fixed displacement pump and in a version for closed center systems with variable displacement pumps.

Open Center version Load-Sensing control block:

In the Open Center version, the load-sensing control block works like a 3-way flow control valve. When the main spool of the directional control valve section is in center position, the load-sensing line is connected to the tank. Therefore, there is no pressure on the spring side of the inlet pressure compensator and the oil is fed by the pump directly into the tank. When the proportional working section is switched, there is a connection of the load-sensing signal on the spring side of the inlet pressure compensator. The highest load pressure is signalled via shuttle valves in the spring chamber, thus creating an open centre load sensing system. The total pump volume flow is divided into the required volume flow for the application and a residual flow to the tank

Closed Center Variant Load-Sensing Control Block

In closed centre systems, the load pressure is reported to the pump control and provided by the pump as required, for which the control block provides an LS signal for the pump. The inlet pressure compensator is blocked in this variant and therefore has no function. When the proportional directional control valve section is actuated, a corresponding load signal is reported to the pump and the consumer is supplied with the required volume flow. The inlet section has a fixed secondary pressure relief valve, which relieves excessive pressure in the pump line to the tank. This section also has an adjustable pressure relief valve (30-350 bar), which is preset to 350 bar. he working section is equipped with shock and suction valves, which protect the outputs A and B and thus the consumer from too high pressures. The pressure cut-off valves LSA and LSB enable efficient pressure limitation by reducing the flow rate provided.