| 摘要 |
A temperature compensating device is disclosed for use in a filter contaminant warning system in a tractor or similar machine. The temperature compensating device is hydraulically connected between the hydraulic filter element inlet and the pressure responsive filter contaminant indicator switch in the warning system. Pressurized fluid from the inlet side of the filter element enters the temperature compensating device through an elongated capillary, and the fluid is discharged simultaneously through a port to the filter contaminant indicator switch and through an orifice to a reservoir. When the fluid is cold and has high viscosity, a substantial part of the total fluid pressure drop between the filter inlet and indicator switch occurs in the capillary portion of the compensating device. The remaining portion of the pressure loss occurs in the orifice. After the fluid temperature has increased, thereby reducing viscosity, the major part of the pressure drop between the filter inlet and indicator switch occurs in the orifice, and the remaining part of the pressure loss occurs in the capillary. The compensating device reduces the pressure at the indicating switch when the fluid is highly viscous or cold and increases the pressure at the switch when the fluid is less viscous. Thus, the temperature compensating device prevents the warning system from switching on falsely due to fluid viscosity changes when a filter restriction does not exist.
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