Surge prevention device
A surge prevention valve may be used to prevent the formation of an initial surge of high pressure. The valve may be located, for example, between a high pressure gas cylinder and a medical pressure regulator. The valve is provided with first and second valves located within a housing and integrating a pressurization orifice. The initial opening of the valve in an axial direction enables gas to flow through the pressurization orifice at a first flow rate. The full opening of the valve in the axial direction enables the gas to flow through the second valve at a second flow rate, which is much higher than the first flow rate. The controlled pressurization of the gas through the orifice delays the time during which the gas reaches full recompression. The valve may be further provided with a vent for venting pressurized gas away from a nominally closed top surface of the lower valve element. The valve may be also provided with a valve inlet tube extending into a gas cylinder to prevent contaminants, particles and/or impurities from entering the valve. In a preferred embodiment of the invention, the valve has a deformable seal element that is sealed on both sides when the main passageway is closed. The deformable element, which may be an apertured disk, may be resiliently bowed or preloaded. This helps the disk remain in the desired position against a first one of the valve seats even after the disk is permanently deformed by the first valve seat.
1. A surge prevention valve comprising:
a housing having an inlet, an outlet, and a flow path from said inlet to said outlet;
a seal unit for closing said flow path, said seal unit including a bleed passageway and a pre-loaded ring-shaped elastomeric element; and
an actuator for opening said bleed passageway and then moving said seal unit to an open valve position to open said flow path and then moving said seal unit to a close valve position, said open valve position being characterized in that said ring-shaped elastomeric element has a bowed or biased configuration.
2. The valve of claim 1 , wherein said seal unit includes a valve seat, and wherein said pre-loaded element is permanently deformed on said valve seat in said close valve position.
3. The valve of claim 2 , wherein an outer edge of said pre-loaded element is biased toward said valve seat in said open valve position.
4. The valve of claim 3 , further comprising a crimped portion for biasing said outer edge of said pre-loaded element.
5. A method of making a dual passageway valve, said method comprising the steps of:
resiliently pre-loading a deformable element;
subsequently, permanently deforming said deformable element on a first valve seat; and
subsequently, moving said deformable element away from a second valve seat to open said dual passageway valve.
6. The method of claim 5 , wherein said step of resiliently pre-loading said deformable element includes the step of causing said deformable element to have a bowed concave surface facing said first valve seat.
7. The method of claim 6 , wherein said first and second valve seats are on opposite sides of said deformable element.