JPS57179389A - Protecting system for hydraulic pump - Google Patents

Abstract

PURPOSE:To permit to prevent the reverse flow of pressurized oil surely upon the trouble of a non-return valve by a method wherein a protecting valve mechanism, normally opened and closed in accompanied with a pressure drop due to the abnormality of the non-return valve, and a pressure converter are provided between the non-return valve and an accumulator. CONSTITUTION:The protecting device 10 is constituted of the protecting valve mechanism 100, interposed between the non-return valve 3 and the accumulator 8, and the pressure converter 200, detecting a pressure at the outlet side of the non-return valve 3 to output a trouble detecting signal such as an electric signal or the like. Supposing the trouble is caused in the non-return valve 3 and the pressurized oil begins to flow reversely, the pressure drop will be caused in a pipeline 11 and the valve chambers A, B of the protecting valve mechanism 100 due to the flow of the oil and a piston 104 will be moved slightly to the left as shown by the diagram. Due to the movement of the piston 104, the pressurized oil flows into the valve chamber D, the piston 104 is moved rapidly until it is seated on a valve seat 102, the reverse flow of the pressurized oil is is precluded, the large pressure drop of the accumulator 8 may be prevented and the function of the whole system may be maintained.