Method for determining leaks of a pressure fluid in a pressure actuated machine using a mathematical equation relating pressure and flow volume and comparing actual values to a reference value

摘要

The method determines leaks in a machine (1) with a fluid actuator (2) in which is located a moveable member (3). This is moved by the actuator through a pressure medium in a working motion. The pressure medium is provided from a pressure medium chamber (6). A pressure sensor (14) arranged in supply lines (5,8,9) between the chamber and the actuator detects the pressure of the medium. A deviation indicates loss of pressure medium. A flow volume sensor (16) in the feed lines detects the flow volume of the fluid pressure medium during the working motion of the moveable member (3). A physical equation relates the pressure measurement value and the flow volume value. In normal operation without any leakage, the coefficients of the equation are matched to the machine to tune this to the actual working motion of the moveable member. When the measured pressure value or flow volume value deviates from a reference value at a given position of the moveable member, or if the position or speed of the member, derived from the equation, deviates from a reference value, leakage of the pressure medium is determined. - Independent claims also cover an apparatus for carrying out the method.