Fluid handling – Diverse fluid containing pressure systems – Gas pressure storage over or displacement of liquid
Reexamination Certificate
1999-01-05
2001-09-04
Walton, George L. (Department: 3753)
Fluid handling
Diverse fluid containing pressure systems
Gas pressure storage over or displacement of liquid
C137S237000, C137S550000, C173SDIG003, C184S007400, C184S055200
Reexamination Certificate
active
06283141
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid dosing or metering device for compressed air tools, wherein the device includes a sealable liquid tank whose lower part is connected to the compressed air inlet on the tool, downstream of its throttle valve, via a flow-restricting or flow-impeding filter element that is in contact with the liquid.
2. Description of the Related Art
Such metering devices are intended to supply a usually very small amount of liquid, normally a suitable oil, to the compressed air inlet downstream of the throttle valve in the event of an interruption in the operation of a compressed air tool. When operation is resumed, this liquid is entrained by the compressed air into the tool. It is difficult to avoid undesirable leakage of the liquid from the tank to the air inlet if there is a long interruption in operation. Moreover, it is difficult to provide, regardless of the liquid level, the desired uniform liquid dosage to the air inlet with every interruption in operation.
SUMMARY OF THE INVENTION
The object of the invention is to provide a novel and advantageous liquid metering device with which the aforesaid difficulties are avoided at least to a substantial extent.
To this end, it is proposed in accordance with the invention that the filter element of a device of the kind defined in the introduction also communicates directly with an upper tank space in the tank above the intended maximum liquid level in said tank. This arrangement is advantageous in that for each interruption in operation the metering device will only dispense the liquid that is already in the filter element, whereafter the pressure in the liquid tank continues to be relieved, i.e. lowered, by forcing essentially only air from the upper tank space to the compressed air inlet via the filter element.
Additional advantageous features of the invention are set forth in the dependent claims.
REFERENCES:
patent: 3581845 (1971-06-01), Van Nederynen
patent: 3977496 (1976-08-01), Black
patent: 5249645 (1993-10-01), Wiklund
patent: 2804665 (1978-08-01), None
patent: 467 320 (1992-06-01), None
Kauppi Sune
Saxback Lars
Atlas Copco Berema AB
Jacobson & Holman PLLC
Walton George L.
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