Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Reexamination Certificate
1999-07-06
2001-01-16
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
C137S510000, C137S860000
Reexamination Certificate
active
06173738
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a pressure maintenance valve for air spring systems and pneumatic apparatus with a housing to which an air supply line originating from a pump and a pressure relief line are connected.
DE 44 38 192 C2 discloses such a pressure maintenance valve. The pressure maintenance valve is to maintain a certain pressure in a consumer, which generally is permanently connected to a pressure source such as a pump or compressor, at a predetermined minimum value when the pump is switched off or has become inoperative or the pressure of the pressure source has dropped or if the consumer has been separated from the pressure source. The known pressure control valve is at least in part of a hose valve design as it has been used in the past bicycle tubes. A supply line connected to a pump terminates in a valve tube which is surrounded by an elastic rubber hose. In contrast to the bicycle tube valve however the duct line leading to the consumer is symmetrical to the supply duct. Also, the rubber hose is fixed at its opposite ends to the valve tube in a gas tight manner. When the rubber hose is expanded by the pump pressure or the consumer pressure, the valve opens. The open position is the normal position, particularly in pneumatic vehicle spring systems. As a result, the rubber hose acting as a valve member is always in a stretched state so that, in time, it loses the elasticity required for appropriate sealing.
It is the object of the present invention to provide a valve member for a pressure maintenance or control valve, which will securely seal in its closed position, which will remain operative over a long life, which comprises only few parts and which requires no servicing.
SUMMARY OF THE INVENTION
In a pressure maintenance valve for pneumatic apparatus including a valve housing having inlet and outlet passages, a valve member is disposed in the housing and includes a membrane having at one side thereof an annular valve structure disposed opposite an annular valve seat which divides the space adjacent the membrane into inner and outer concentric chambers when the valve structure is seated on the valve seat. A valve spring is disposed at the other side of the membrane for biasing the membrane into engagement with the valve seat. One of the concentric chambers is in communication with the inlet passage and the other with the outlet passage, whereby the membrane is held in an open valve position as long as the pressure in the inlet and outlet passages is greater than a certain value but the membrane closes the valve to maintain the predetermined pressure in the outlet passage when the pressure falls below the certain value. The membrane is manufactured in the shape, which it assumes in its valve opening position.
The membrane may be for example in the form of planar apertured disk consisting of a rubber-like elastic material which has the shape in which it was manufactured when the gas pressure in the pressure control valve is at normal system operating pressure. Only when the system pressure falls to a given maintenance level the membrane is deformed to close the valve.
In order to increase the flexibility and/or improve its sealing function, the membrane may have one or several concentric corrugations extending from one or both sides thereof.
REFERENCES:
patent: 2639194 (1953-05-01), Wahlin
patent: 3566913 (1971-03-01), Parthe
patent: 3642026 (1972-02-01), Sielaff
patent: 44 38 192 (1996-05-01), None
patent: 2 308 424 (1997-06-01), None
patent: 64 203127 (1991-03-01), None
Lohmann Gerhard
Opara Andreas
Bach Klaus J.
Daimler-Chrysler AG
Hepperle Stephen M.
LandOfFree
Pressure maintenance valve for pneumatic apparatus such as... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pressure maintenance valve for pneumatic apparatus such as..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pressure maintenance valve for pneumatic apparatus such as... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2494594