Backflow preventer

Apparatus comprising:

• a backflow preventer, including
• a body, wherein the body includes
• a central bore, wherein the central bore extends along an axis,
• an inlet port, wherein the inlet port is in fluid connection with the central bore,
• an outlet port, wherein the outlet port is in fluid connection with the central bore,
• wherein the body is comprised of aluminum with a less than 2° C. sulfuric acid electrolyte produced anodized coating having an aluminum oxide surface coating thickness of from 0.003 to 0.007 inches,
• a first check valve element, wherein the first check valve element is removably positioned in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction, wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is removably positioned in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.

Apparatus comprising:

• a backflow preventer, including
• a body, wherein the body includes
• a central bore, wherein the central bore extends along an axis,
• an inlet port, wherein the inlet port is in fluid connection with the central bore,
• an outlet port, wherein the outlet port is in fluid connection with the central bore,
• a first pressure relief port, wherein the first pressure relief port is in direct fluid connection with the inlet port,
• a second pressure relief port, wherein the second pressure relief port is in direct fluid connection with the central bore fluidly intermediate of a first sealed location and a second sealed location,
• a third pressure relief port, wherein the third pressure relief port is in direct fluid connection with at least one of
• the outlet port, and
• the central bore fluidly intermediate of the second sealed location and the outlet port,
• a first pressure indicating port, wherein the first pressure indicating port is in direct fluid connection with the central bore fluidly intermediate of the first sealed location and the second sealed location,
• a second pressure indicating port, wherein the second pressure indicating port is in direct fluid connection with at least one of
• the outlet port, and
• the central bore fluidly intermediate of the second sealed location and the outlet port,
• a first check valve element, wherein the first check valve element is removably positioned in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction, wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is removably positioned in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction,
• wherein the first check valve element in the first check valve element closed position prevents fluid flow through the central bore at the first sealed location and wherein the second check valve element in the second check valve element closed position prevents fluid flow through the central bore at the second sealed location,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.

Apparatus comprising:

• a backflow preventer, including
• a body,
• wherein the body is comprised of a single piece of aluminum with either
• an aluminum oxide anodized surface coating or
• an unsealed anodized surface,
• wherein the body includes
• a central bore, wherein the central bore extends along an axis,
• an inlet port, wherein the inlet port is axially centered and in fluid connection with the central bore,
• an outlet port, wherein the outlet port is axially centered and in fluid connection with the central bore,
• a first check valve element, wherein the first check valve element is removably positioned in axially centered relation in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction, wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is removably positioned in axially centered relation in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.

Apparatus comprising:

• a backflow preventer, including
• a body comprised of a single piece of translucent body material, wherein the body includes
• a central bore, wherein the central bore extends along an axis,
• an inlet port, wherein the inlet port comprises a threaded inlet port that extends in the body and is in fluid connection with the central bore,
• wherein an inlet port overlying surface outwardly annularly overlies the inlet port on an outer surface of the body,
• an outlet port, wherein the outlet port is in fluid connection with the central bore,
• a continuous annular inlet reinforcing ring, wherein the inlet reinforcing ring is comprised of a different material than the body material and extends in surrounding relation of the inlet port overlying surface,
• a first check valve element, wherein the first check valve element is removably positioned in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction, wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is removably positioned in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.

Apparatus comprising:

• a backflow preventer, including
• a body comprised of a single piece of transparent material, wherein the body includes
• a central bore, wherein the central bore extends along an axis,
• an inlet port, wherein the inlet port is in fluid connection with the central bore,
• an outlet port, wherein the outlet port comprises a threaded outlet port that extends in the body and is in fluid connection with the central bore,
• wherein an outlet port overlying surface outwardly radially annularly overlies the outlet port on an outer surface of the body,
• a continuous annular outlet reinforcing ring, wherein the outlet reinforcing ring is comprised of a different material than the body material and extends in surrounding relation of the outlet port overlying surface,
• a first check valve element, wherein the first check valve element is removably positioned in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction, wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is removably positioned in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.

Apparatus comprising:

• a backflow preventer, including
• a body comprised of a single piece of body material, wherein the body includes
• a central bore, wherein the central bore extends along an axis,
• an inlet port, wherein the inlet port comprises a threaded inlet port that extends in the body and is in fluid connection with the central bore,
• wherein an inlet port overlying surface radially outwardly annularly overlies the inlet port on an outer surface of the body,
• an outlet port, wherein the outlet port comprises a threaded outlet port that extends in the body and is in fluid connection with the central bore,
• wherein an outlet port overlying surface radially outwardly annularly overlies the outlet port on the outer surface of the body,
• a continuous annular inlet reinforcing ring, wherein the inlet reinforcing ring is comprised of a different material than the body material and extends in surrounding relation of the inlet port overlying surface,
• a continuous annular outlet reinforcing ring, wherein the outlet reinforcing ring is comprised of a further different material than the body material and extends in surrounding relation of the outlet port overlying surface,
• a first check valve element, wherein the first check valve element is removably positioned in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction, wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is removably positioned in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.

Apparatus comprising:

• a backflow preventer, including
• a body, wherein the body includes
• a central bore, wherein the central bore extends along an axis,
• an inlet port, wherein the inlet port is axially centered and in fluid connection with the central bore,
• an outlet port, wherein the outlet port is axially centered and in fluid connection with the central bore,
• a first pressure relief port, wherein the first pressure relief port is in direct liquid connection with the inlet port,
• a second pressure relief port,
• a third pressure relief port,
• a first check valve element, wherein the first check valve element is removably positioned in axially centered relation in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction at a first sealed location,
• wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is removably positioned in axially centered relation in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction at a second sealed location,
• wherein the second pressure relief port is in direct liquid connection with the central bore fluidly intermediate of the first sealed location and the second sealed location,
• wherein the third pressure relief port is in direct liquid connection with at least one of
• the outlet port, and
• the central bore fluidly intermediate of the second sealed location and the outlet port,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.

Apparatus comprising:

• a backflow preventer, including
• a body, wherein the body includes
• a central bore, wherein the central bore comprises a cylindrical bore that extends along an axis,
• an inlet port, wherein the inlet port is axially centered and in fluid connection with the central bore,
• an outlet port, wherein the outlet port is axially centered and in fluid connection with the central bore,
• a first check valve element, wherein the first check valve element is removably positioned in axially centered relation in the central bore, wherein the first check valve element is axially movable when positioned within the bore between a first check valve element open position and a first check valve element closed position,
• wherein in the first check valve element open position liquid is enabled to flow axially in the central bore in a first axial flow direction past the first check valve element, and
• wherein in the first check valve element closed position liquid is prevented from flowing in the central bore in an opposed flow direction, wherein the opposed flow direction is opposite of the first axial flow direction,
• a second check valve element, wherein the second check valve element is movably mounted on a second check valve cylindrical body that includes at least one radially extending back face, wherein the second element check valve is removably positioned in axially centered relation in the central bore, wherein the second check valve element is axially disposed in the bore from the first check valve element,
• wherein the second check valve cylindrical body is axially movable in the central bore,
• wherein the second check valve element is axially movable when positioned within the bore between a second check valve element open position and a second check valve element closed position,
• wherein in the second check valve element open position liquid is enabled to flow within the central bore in the first axial flow direction past the second check valve element, and
• wherein in the second check valve element closed position liquid is prevented from flowing in the central bore in the opposed flow direction,
• wherein the central bore includes a first axial end, wherein the central bore adjacent the first axial end includes a radially inward extending step surface, wherein the at least one radially extending back face is in abutting operatively engaged relation with the radially inward extending step surface,
• wherein the second check valve cylindrical body is axially held in position in the central bore through operative engagement of the at least one back face and the step surface,
• wherein the central bore includes a second axial end axially opposed of the first axial end, wherein the second axial end includes an insertion opening, wherein the second check valve cylindrical body is removably positioned in the central bore through the insertion opening,
• wherein the first check valve element is movably mounted on a first check valve cylindrical body,
• wherein the first check valve cylindrical body is axially movable in the central bore,
• wherein the first check valve cylindrical body is removably positioned in the central bore through the insertion opening,
• and further including a spacer,
• wherein the spacer is positioned in the central bore axially intermediate of the first check valve cylindrical body and the second check valve cylindrical body,
• wherein the spacer is axially movable in the central bore and is removably positioned in the central bore through the insertion opening,
• wherein responsive to liquid pressure acting in the first axial flow direction
• the first check valve element is movable from the first check valve element closed position to the first check valve element open position, and
• the second check valve element is movable from the second check valve element closed position to the second check valve element open position.