Low-cost hydraulic force reduction in a manually-operated high-performance directional control poppet valve

The article presents the results of research into the use of hydraulic force reduction in a manually-controlled directional control poppet valve, used in hydraulic systems of powered roof supports, part of longwall complexes used while mining in hard coal mines. Hydraulic force reduction is intended to enable enlargement of the valve elements, and therefore the efficiency of the directional control valve without an increase in control forces or losing the basic feature of the directional control valve, i.e., a high seal level when closing the medium flow. A number of prototype tests were designed and carried out to experimentally confirm the possibility of using hydraulic force reduction.