Valves and valve actuation – With correlated flow path – Valve operated by joining flow path sections
Reexamination Certificate
1999-12-27
2001-08-14
Shaver, Kevin (Department: 3754)
Valves and valve actuation
With correlated flow path
Valve operated by joining flow path sections
C251S149900, C251S221000, C251S225000, C137S614180
Reexamination Certificate
active
06273397
ABSTRACT:
BACKGROUND
The present invention relates to improved fittings for air conditioning systems, and in particular to fittings that provide low leakage rates.
Modem air conditioning systems, such as those used on automotive vehicles, are typically provided with one or more access fittings used to charge, reclaim and service the refrigerant within the system. Such access fittings preferably provide extremely low leakage rates when closed, but they can be opened easily when needed for routine service operations.
One prior-art approach to air conditioner access fittings is to use a spring-loaded valve core that provides an elastomer-to-metal seal. Such fittings are disclosed in the following U.S. patents: Gilbert U.S. Pat. No. 4,979,721 (assigned to the assignee of the present invention), Manz U.S. Pat. No. 5,080,132, Hale U.S. Pat. No. 5,010,743, Starr U.S. Pat. No. 4,753,267, Mullins U.S. Pat. No. 3,996,745, and Rawlins U.S. Pat. No. 3,645,496.
Although such access fittings have been found suitable for a wide variety of applications, the minimum leakage rate of refrigerant is limited by the rate at which refrigerant diffuses through the elastomeric sealing element of the valve core. Access fittings such as those described in the above-identified Gilbert patent include a quick release shoulder on an exterior surface of the valve body.
Metal-to-metal valves are known to the art, as described for example in Mitchell U.S. Pat. No. 5,915,402 and Taylor U.S. Pat. No. 4,932,434. However, these metal-to-metal valves are not illustrated as adapted for use with quick connect couplers, and thus they are not well suited for use as refrigerant access fittings intended for use with quick connect couplers.
SUMMARY
The present invention is directed to a low leakage air conditioner access valve that is well suited for use with quick connect couplers.
The preferred embodiment described below combines a twist-to-open valve that provides an extremely low leakage, metal-to-metal seal. A valve core is disposed in a central bore in the twist-to-open valve, and refrigerant cannot pass through the access fitting until the twist-toopen valve is opened by rotating it relative to the valve body, and the valve core is opened by depressing the valve core stem. The valve body defines an annular external quick release shoulder, and the disclosed access fitting is used with a service fitting that includes a quick release mechanism to engage the quick release shoulder, a wrench to engage the twist-toopen valve, and a valve core depressor to depress the valve core stem.
The foregoing paragraphs have been provided by way of introduction, and they are not intended to limit the scope of the following claims.
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Gilbert Major H.
Schultz Jeffrey A.
Bonderer D. H.
Brinks Hofer Gilson & Lione
Schrader-Bridgeport International, Inc.
Shaver Kevin
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