Fluid handling – Diverse fluid containing pressure systems – Fluid separating traps or vents
Reexamination Certificate
1999-10-27
2001-06-19
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Diverse fluid containing pressure systems
Fluid separating traps or vents
C137S199000
Reexamination Certificate
active
06247487
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a valve assembly and more particularly, to a valve assembly which allows air or gas to be discharged from a hydraulic circuit and/or from a portion of a hydraulic circuit and which substantially prevents the discharged air or gas from passing back into and/or re-entering the circuit and/or the portion of the hydraulic circuit from which the air or gas was previously expelled.
BACKGROUND OF THE INVENTION
Valve assemblies are used within vehicles and other apparatuses and assemblies to control the flow of fluids, gasses, and/or other materials between various interconnected and/or communicating portions or chambers which are respectively contained and/or resident within these vehicles, apparatuses, and assemblies.
One type of valve assembly, known as an “air bleed” check valve assembly, is typically disposed within a hydraulic circuit (e.g. within the hydraulic circuit of a vehicle clutch assembly), and operatively allows air or gas to pass from a portion of the hydraulic circuit and through the valve assembly, while substantially and concomitantly preventing hydraulic fluid from escaping and/or exiting from the hydraulic circuit and from passing through the valve assembly.
This type of valve assembly typically includes a “check ball” or member which is contained within a channel or slot. The channel includes an aperture or passage through which the gas or air, escaping and/or exiting from a portion of the hydraulic circuit, may pass. The aperture is substantially surrounded by a valve seat. The ball member is movable between a first position in which the ball member resides upon the valve seat, and a second position in which the ball member does not reside on the seat (e.g., in which the ball member is remotely positioned from the ball seat), thereby allowing air or gas to pass through the aperture, to be received within a certain portion of the valve assembly, and to be expelled from the valve assembly. The selective movement of the ball member allows gas or air to be expelled and/or discharged from a portion of the hydraulic circuit and to be communicatively transferred and/or moved through the valve assembly, while substantially preventing hydraulic fluid from being expelled from the circuit. Particularly, the flow of the relatively high density hydraulic fluid into the valve assembly causes the ball member to move from the second position to the first position, thereby covering the aperture and preventing the hydraulic fluid from passing through the aperture and through the valve assembly.
While this prior type of valve assembly is relatively effective to operatively expel/discharge and/or communicatively transfer gas or air from and/or by and between portions of a hydraulic circuit, it suffers from some drawbacks which adversely effect its performance.
For example and without limitation, when air or gas is passed through this prior type of valve assembly, the pressure on the other side or portion of the valve assembly (the side or portion which receives the “passed” or discharged air or gas) is often increased. This increase in pressure typically results in and/or causes air to flow or “bleed” back through the valve assembly and into the portion of the hydraulic circuit from which the air or gas had been expelled. This “back flow” or “drain back” of air or gas into the hydraulic circuit causes the circuit to have inconsistent system operating and response characteristics and to be “unstable”. For example and without limitation, the amount of time required to achieve and maintain a certain pressure within the circuit varies, is not readily ascertainable, and is undesirably increased due to this back flow of air or gas into the circuit.
There is therefore a need for a new and improved valve assembly for use in combination with a hydraulic circuit or device; which allows gas or air to exit from the hydraulic circuit and to pass through the valve assembly while substantially preventing hydraulic fluid from exiting the hydraulic circuit; which substantially prevents the previously expelled air and/or gas from flowing back into the portion of the hydraulic circuit from which the air or gas has been expelled; and which substantially improves the overall stability and operating characteristics of the hydraulic circuit.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide a valve assembly which overcomes some or all of the previously delineated drawbacks of prior valve assemblies.
It is a second object of the invention to provide a valve assembly for use within a hydraulic circuit and which allows gas and/or air to be selectively discharged and/or to exit from the hydraulic circuit and to pass through the valve assembly, while substantially preventing hydraulic fluid from exiting from the hydraulic circuit and passing through the valve assembly, and which substantially and concomitantly prevents the previously discharged gas and/or air from flowing back into the hydraulic circuit and/or into the portion of the hydraulic circuit from which the air or gas was discharged.
It is a third object of the present invention to provide a valve assembly for use within a hydraulic circuit and which allows the circuit to substantially and consistently achieve a certain pressure within a relatively short period of time.
According to a first aspect of the present invention, a valve assembly is provided for use in combination with a circuit having a first portion containing a fluid and a gas and a second portion. The valve assembly includes a first member having a channel which is communicatively coupled to the first portion of the circuit and to the second portion of the circuit. A first sealing element is movably disposed within the channel and is effective to allow the gas to pass from the first portion of the circuit to the second portion of the circuit, while substantially preventing the fluid from passing from the first portion of the circuit to the second portion of the circuit. A second sealing element is movably disposed within the channel and is effective to allow the gas to pass from the first portion of the circuit to the second portion of the circuit, while substantially preventing the gas from passing from the second portion of the circuit to the first portion of the circuit.
According to a second aspect of the present invention, a method for controlling the flow of gas and hydraulic fluid between a first portion and a second portion of a hydraulic circuit is provided. The method includes the steps of allowing the gas to flow from the first portion to the second portion; preventing hydraulic fluid from flowing from the first portion to the second portion; and preventing the gas from flowing from the second portion to the first portion.
These and other objects, aspects, features, and advantages of the present invention will become apparent from a consideration of the following specification and the attached drawings.
REFERENCES:
patent: 2299473 (1942-10-01), Eggleston
patent: 2544476 (1951-03-01), Venning
patent: 2549035 (1951-04-01), White
patent: 2627868 (1953-02-01), Runnels
patent: 2729228 (1956-01-01), Stevenson
patent: 4813446 (1989-03-01), Silverwater et al.
patent: 5107890 (1992-04-01), Gute
patent: 995919 (1965-06-01), None
Ford Global Tech. Inc
Ford Global Tech., Inc.
Michalsky Gerald A.
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