Determining the level of particulate contamination in a fluid power system

A contaminant monitor for determining the level of particulate contamination suspended in the working fluid of a fluid power system comprising:

• a) an inlet means for directing said working fluid into the contaminant monitor;
• b) an outlet means directing said working fluid from the contaminant monitor;
• c) a fluid passage extending between said inlet means and said outlet means through which said working fluid carrying suspended particulates is passed;
• d) a means for reversing flow having first and second flow states, wherein when the flow reversal means is in said first flow state, the fluid flows through said fluid passage in the first direction, and when said flow reversal means is in said second flow state, the fluid flows through said fluid passage in the second direction;
• e) an orifice adapted for use to have access to said fluid passage in said first flow state, said orifice sized to cause entrapment of said suspended particulates to be sensed, wherein said entrapment causes the fluid flow rate in said first direction to reduce;
• f) a means for detecting said fluid flow rate of said working fluid traversing said fluid passage in said first direction;
• g) a means for flushing the entrapped particulates, said flushing means adapted for use to have access to said fluid passage in said second flow state;
• h) a means responsive to said flow rate detector means for recording the occurrence of said fluid flow reduction, for setting the flow reversal means to the second flow state, and for restoring said flow reversal means to the first flow state;
• i) wherein said fluid flow detector means being adapted to detect reduction in the rate of flow of said working fluid as said orifice becomes blocked by solid particulates, wherein the progressive and characteristic reduction of flow rate is used to indicate the level of particulate contaminations.