Leak monitor for hydraulic drive systems
First Claim
1. Method of operating a hydraulic machine unit which is selectively connected by means of at least one conduit to a tank or a pump, said conduit being under a residual pressure when connected to the tank during idling of the machine, characterized in that the residual pressure in the conduit is set to a desired value, that an actual value of the residual pressure in the conduit is measured and is compared with the desired value of the residual pressure and that a leak is indicated when the actual value of the residual pressure sinks below the desired value thereof.
1 Assignment
0 Petitions
Accused Products
Abstract
The drive systems include at least one conduit leading to a machine unit which may be selectively connected to a pump or a tank. Arranged in the conduit is a holding valve which, when the conduit is connected to the tank, maintains a minimum pressure in the conduit branch leading to the machine unit. A pressure sensor arranged in this conduit branch determines the actual value of the conduit pressure. If this decreases with respect to the minimum pressure predetermined by the opening pressure of the holding valve, which is determined by a comparison device, this is an indication that the conduit section has a leak, if only a small one.
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Citations
20 Claims
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1. Method of operating a hydraulic machine unit which is selectively connected by means of at least one conduit to a tank or a pump, said conduit being under a residual pressure when connected to the tank during idling of the machine, characterized in that the residual pressure in the conduit is set to a desired value, that an actual value of the residual pressure in the conduit is measured and is compared with the desired value of the residual pressure and that a leak is indicated when the actual value of the residual pressure sinks below the desired value thereof.
- 2. Hydraulic drive system for working machines with a tank, a pump connected thereto and at least one conduit leading to a machine unit for the supply and return of hydraulic fluid, the conduit starting from a control device, characterized in that arranged in the conduit (14, 15) leading to a machine unit (16) there is a holding valve (17) with an opening pressure set to correspond to at least the biasing pressure prevailing in the conduit during idling of the machine and a pressure sensor (18) between each holding valve (17) and the machine unit (16) for measuring an actual value of the pressure in the conduit, whereby the actual value of the pressure is transmitted to a device (19) for comparing the actual value with the predetermined opening pressure as a desired pressure value.
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12. Drive system as claimed in calim 2, characterised in that the opening pressure predetermined in the device (19) as a desired value corresponds to the biasing pressure prevailing during idling of the machine.
Specification