A backflow preventer that includes a housing having an inlet and an outlet adapted to be mounted in a liquid flow configuration in a liquid supply circuit. An upstream check disc assembly is positioned in the housing downstream of the inlet, and includes an upstream check plate supporting a downstre
A backflow preventer that includes a housing having an inlet and an outlet adapted to be mounted in a liquid flow configuration in a liquid supply circuit. An upstream check disc assembly is positioned in the housing downstream of the inlet, and includes an upstream check plate supporting a downstream diaphragm. An upstream check disc is positioned downstream of the diaphragm and integrally formed with an upstream stem mounted in an aperture in a central hub formed in the check plate for movement between a normally open, flow position and a closed position preventing backflow of liquid through the inlet. A downstream check disc assembly is positioned in the housing downstream from the upstream check disc assembly. A vent discharges liquid to atmosphere upstream of the downstream check disc assembly.
대표청구항▼
1. A backflow preventer, comprising: (a) a housing having an inlet and an outlet, and adapted to be mounted in a liquid flow configuration in a liquid circuit;(b) an upstream check disc assembly positioned in the housing downstream of the inlet, and including an upstream check plate supporting a dia
1. A backflow preventer, comprising: (a) a housing having an inlet and an outlet, and adapted to be mounted in a liquid flow configuration in a liquid circuit;(b) an upstream check disc assembly positioned in the housing downstream of the inlet, and including an upstream check plate supporting a diaphragm positioned downstream from the upstream check plate, wherein the upstream check plate includes a plurality of closely-spaced apart flow ports therethrough extending around the periphery thereof, and a plurality of radially-inwardly positioned flow ports surrounding the central hub of the upstream check plate, the diaphragm including a peripheral annular rib and a central seal portion comprising a downstream, axially-extending intermediate support rib and an inner, radially-extending seal portion, the peripheral annular rib being captured in a seal channel of the housing, the axially-extending intermediate support rib engaging a support ring adapted to limit downstream movement of the diaphragm, and the central seal portion engaging an annular inner wall of the housing to limit downstream movement of the diaphragm from a position radially inward from the intermediate support rib;(c) an upstream check disc positioned downstream of the diaphragm and unitarily-formed with a stem and concentrically-mounted on the upstream check disc and extending upstream from the upstream check disc and mounted in an aperture in a central hub formed in the check plate for movement between an normally open, flow position and a closed position preventing backflow of liquid through the inlet;(d) a downstream check disc positioned in the housing downstream from the upstream check disc and including a stem integrally-formed and concentrically-mounted on the downstream check disc and extending upstream from the downstream check disc and mounted in an aperture formed in the housing for movement between an normally open, flow position and a closed position preventing backflow of liquid through the inlet; and(e) a vent from the housing upstream of the downstream check disc assembly and downstream of the upstream check disc assembly to atmosphere. 2. A backflow preventer according to claim 1, wherein a downstream facing face of the upstream check disc and the downstream facing face of the downstream check disc are convex. 3. A backflow preventer according to claim 1, and including a diaphragm support ring positioned in the housing downstream of and sealing against an annular rib formed in a downstream side of the diaphragm of the upstream check disc in both the open, flow and closed positions. 4. A backflow preventer according to claim 1, wherein the upstream check plate is adapted to support the diaphragm on an upstream side of the upstream check plate, and includes: (a) an outer, annular face engaging the diaphragm;(b) an outer plurality of flow ports for allowing liquid to pass through the check plate and downstream around a centrally-formed opening in the diaphragm;(c) a central opening in the check plate;(d) an integrally-formed hub positioned in the central opening in the check plate; and(e) a plurality of spokes extending radially outwardly from the hub and defining a plurality of voids for allowing liquid to pass through the check plate and downstream around a centrally-formed opening in the diaphragm. 5. A backflow preventer according to claim 1, wherein a support washer is positioned against an upstream side of the upstream check disc and a support washer is positioned against an upstream side of the downstream check disc. 6. A backflow preventer according to claim 5, wherein the support washer positioned against the upstream side of the upstream check disc is fabricated of an elastomeric material and is adapted to seal against liquid flow when in the closed position against the diaphragm. 7. A backflow preventer according to claim 5, wherein the support washer positioned against the upstream side of the downstream check disc is fabricated of an elastomeric material and is adapted to seal against liquid flow when in the closed position against the flow opening in the wall of the housing. 8. A backflow preventer, comprising: (a) a housing having an inlet and an outlet, and adapted to be mounted in a liquid flow configuration in a liquid supply circuit;(b) an upstream check disc assembly positioned in the housing downstream of the inlet, and including an upstream check plate supporting a diaphragm positioned downstream thereof, wherein the upstream check plate is adapted to support the diaphragm on an downstream side of the upstream check plate, and includes an outer, annular face engaging the diaphragm, an outer plurality of flow ports for allowing liquid to pass through the check plate and downstream around a centrally-formed opening in the diaphragm, a central opening in the check plate, an integrally-formed hub positioned in the central opening in the check plate, and a plurality of spokes extending radially outwardly from the hub and defining a plurality of voids for allowing liquid to pass through the check plate and downstream around the centrally-formed opening in the diaphragm ;(c) the diaphragm including a peripheral annular rib and a central seal portion comprising a downstream, axially-extending intermediate support rib and an inner, radially-extending seal portion, the peripheral annular rib being captured in a seal channel of the housing, the axially-extending intermediate support rib engaging a downstream support ring adapted to limit downstream movement of the diaphragm, and the central seal portion engaging an annular inner wall of the housing to limit downstream movement of the diaphragm from a position radially inward from the intermediate support rib;(d) an upstream check disc positioned downstream of the diaphragm and integrally formed with a stem extending upstream from the upstream check disc and mounted in an aperture in the hub formed in the upstream check plate for movement between an normally open, flow position and a closed position preventing backflow of liquid through the inlet;(e) a downstream check disc assembly positioned in the housing downstream from the upstream check disc assembly, and including a downstream check disc integrally formed with a stem extending upstream thereof and mounted in an aperture in a central hub formed in a flow opening in a wall of the housing for movement between an normally open, flow position and a closed position preventing backflow of liquid through the outlet; and(f) a vent from the housing upstream of the downstream check disc assembly and downstream of the upstream check disc assembly to atmosphere. 9. A backflow preventer according to claim 8, wherein a downstream facing face of the upstream check disc and the downstream facing face of the downstream check disc are convex. 10. A backflow preventer according to claim 8, and the upstream check disc assembly including a diaphragm support ring positioned in the housing downstream of and sealing against an annular rib formed in a downstream side of the diaphragm in both the open, flow and closed positions. 11. A backflow preventer according to claim 8, wherein the upstream check disc and the downstream check disc are each spring-biased in normally closed position and adapted to be held open by a normal flow condition through the backflow preventer. 12. A backflow preventer according to claim 8, wherein a support washer is positioned against an upstream side of the upstream check disc and a support washer is positioned against an upstream side of the downstream check disc. 13. A backflow preventer according to claim 12, wherein the support washer positioned against the upstream side of the upstream check disc is fabricated of an elastomeric material and is adapted to seal against liquid flow when in the closed position against the diaphragm. 14. A backflow preventer according to claim 12, wherein the support washer positioned against the upstream side of the downstream check disc is fabricated of an elastomeric material and is adapted to seal against liquid flow when in the closed position against the flow opening in the wall of the housing.
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이 특허에 인용된 특허 (6)
Tripp,Dale S., Back flow preventer made of at least two different types of material.
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