Diaphragm valve

Claim 2

A valve for controlling flow in response to downstream pressure variation, said valve including a housing having means at least partially defining a flow passageway having a port surrounded by a valve seat, said port separating an upstream portion of said flow passageway from a downstream portion, a diaphragm supported by said housing, cooperating with said housing to define said flow passageway, and being movable relative to said port between a port closing position and a port opening position, said diaphragm including a first side subject to the pressure condition in said downstream passageway portion and a second side subject, in part, to the pressure condition in said upstream passageway portion, a spring having an end with a diameter larger than said valve seat, and a support member interposed between said diaphragm and said spring and including a central portion extending inwardly of the adjacent end of said spring in spaced relation to said diaphragm and an outer portion extending radially outwardly from the periphery of said central portion and engaged with said spring and said diaphragm, whereby to locate said diaphragm in said port closing position in the absence of a pressure differential between said upstream and downstream passageway portions, whereby, when said downstream passageway portion is subject to a pressure condition less than the pressure condition in said upstream portion, such pressure differential produces a first force which acts in opposition to said spring and so as to urge said diaphragm toward said port opening position, and whereby, when the pressure condition in said downstream passageway portion is higher than the pressure condition in said upstream passageway portion, such pressure differential produces a second force acting counter to said first force and in common with said spring so as to urge said diaphragm toward said port closing position.

Claim 3

A valve in accordance with claim 1 wherein said diaphragm is peripherally supported by said housing in a plane located in spaced relation from said valve seat in the direction away from said valve seat.

Claim 4

A valve in accordance with claim 1 and further including a cover connected to said housing in spaced relation from said valve seat and defining together with said diaphragm, a chamber located on the other side of said diaphragm from said valve seat and communicating with said downstream passageway.

Claim 5

A valve in accordance with claim 1 wherein said spring engages said support member at the juncture of said central portion and said outer portion.

Claim 6

A valve in accordance with claim 3 wherein the outer diameter of said central portion exceeds the outer diameter of said valve seat and the part of said diaphragm at the periphery of said central portion of said support member is located, under the influence of said spring and in the absence of a pressure differential between said upstream and downstream passageway portions, more remotely from said cover than said valve seat.

Claim 7

A valve in accordance with claim 1 in further combination with a fuel tank connected to said upstream passageway portion and an engine carburetor.

Claim 8

A valve in accordance with claim 1 in further combination with a fuel tank and a cap removably mounted on said tank in sealing engagement therewith and wherein said housing is carried by said cap and said downstream passageway portion communicates with the interior of said tank and said upstream passageway portion communicates with the atmosphere through passage means extending in said cap.

Claim 9

A valve for controlling flow in response to downstream pressure variation, said valve including a cover and a housing connected to said cover and having means at least partially defining a flow passageway having a port surrounded by a valve seat located in spaced relation from said cover, said port separating an upstream portion of said flow passageway from a downstream portion, a diaphragm peripherally supported between said housing and said cover and located between said housing and said cover so as to further define said flow passageway, and to define, in cooperation with said cover, a chamber in communication with said downstream passageway portion, said diaphragm being movable relative to said port between a port closing position and a port opening position, and including a first side subject to the pressure condition in said downstream passageway portion and a second side subject, in part, to the pressure condition in said upstream passageway portion, a diaphragm support member engaged with said diaphragm in an area located solely radially outwardly of said valve seat and including an annular portion engaged with said diaphragm and having a diameter larger than said valve seat, and a spring engaged between said cover and said annular portion of said support member so as to locate said diaphragm in said port closing position in the absence of a pressure differential between said upstream and downstream passageway portions, whereby, when said downstream passageway portion is subject to a pressure condition less than the pressure condition in said upstream portion, such pressure differential produces a force which acts in opposition to said spring and so as to urge said diaphragm toward said port opening position, and whereby, when the pressure condition in said downstream passageway portion is higher than the pressure condition in said upstream passageway portion, such pressure differential produces a second force acting counter to said first force and in common with said spring so as to urge said diaphragm toward said port closing position.

Claim 10

A valve for controlling flow in response to downstream pressure variation, said valve including a cover and a housing connected to said cover and having means at least partially defining a flow passageway having a port surrounded by a valve seat located in spaced relation from said cover, said port separating an upstream portion of said flow passageway from a downstream portion, a diaphragm peripherally supported between said housing and said cover and located between said housing and said cover so as to further define said flow passageway, and to define, in cooperation with said cover, a chamber in communication with said downstream passageway portion, said diaphragm being movable relative to said port between a port closing position and a port opening position, and including a first side subject to the pressure condition in said downstream passageway portion and a second side subject, in part, to the pressure condition in said upstream passageway portion, a diaphragm support member engaged with said diaphragm in an area located solely radially outwardly of said valve seat and including an annular portion engaged with said diaphragm and having a diameter larger than said valve seat, and a spring engaged between said cover and said annular portion of said support member so as to locate said diaphragm in said port closing position in the absence of a pressure differential between said upstream and downstream passageway portions, whereby, when said downstream passageway portion is subject to a pressure condition less than the pressure condition in said upstream portion, such pressure differential produces a force which acts in opposition to said spring and so as to urge said diaphragm toward said port opening position, and whereby, when the pressure condition in said downstream passageway portion is higher than the pressure condition in said upstream passageway portion, such pressure differential produces a second force acting counter to said first force and in common with said spring so as to urge said diaphragm toward said port closing position.

Claim 11

A valve in accordance with claim 8 wherein said diaphragm is peripherally supported between said housing and said cover in a plane located in spaced relation from said valve seat and toward said cover.

Claim 12

A valve in accordance with claim 8 wherein said support member includes a central portion extending from said annular portion toward said cover and in spaced relation to said diaphragm inwardly of the adjacent end of said spring and an outer portion extending radially outwardly from said annular portion and toward said cover.

Claim 13

A valve in accordance with claim 10 wherein said spring engages said support member at the juncture of said central portion and said outer portion.

Claim 14

A valve in accordance with claim 10 wherein the outer diameter of said central portion exceeds the outer diameter of said valve seat and the part of said diaphragm at the periphery of said central portion of said support member is located, under the influence of said spring and in the absence of a pressure differential between said upstream and downstream passageway portions, more remotely from said cover than said valve seat.