| 摘要 |
<p>A device for determining the level of particulate contamination in a hydraulic system. Between the inlet (1) and outlet (5) of the device the fluid passes through the narrow clearance (4) between a piston (3) and a surrounding bore. As the clearance (4) becomes obstructed by contaminant, pressure rises in a chamber (2) upstream of the piston (3). Rise of this pressure above a certain level is detected by a detector (6, 7, 8) which both triggers a counter (10) and operates a solenoid (9) to withdraw the piston (3) and release trapped contaminant, after which the piston (3) returns and another cycle of contaminant build-up begins. The frequency of the release of the piston (3) indicates the degree of contamination of the fluid. Instead of pressure build-up, parameters related to fluid flow may be used to trigger the counter (10) and the release of contaminants from clearance (4) and means (62,65,) may be provided to meter individual, fixed-volume charges from the general body of fluid and discharge them through a clearance. The clearance (57, may as an alternative be arranged to be cleared by back flushing.</p> |
