Pressure-vacuum control valve

Claim 2

A control valve for maintaining the pressure of a fluid on one side of said valve substantially at the same level as the pressure of the fluid on the other side of said valve, comprising first and second valve members communicating respectively with the fluid on opposite sides of said valve and defining a path for the flow of fluid through said valve from one side to the other side of said valve, means operatively connected to said first and second valve members and engaging for normally sealing off said flow path to prevent the flow of fluid through said valve and adapted to open said flow path in response to an increase in pressure on said one side of said engagement of said sealing means relative to the other side of said engagement of said sealing means, means defining a restriction in said flow path opening into a chamber larger in cross section than said restriction defined between said first and second valve members on said one side of said sealing means, said restriction and chamber being effective upon the flow of fluid therethrough to create a pressure drop in said chamber on said one side of said sealing means, thereby to reduce the fluid pressure on said one side of said sealing means.

Claim 3

The control valve of claim 1, further comprising said valve members being mounted for relative movement, and means normally biasing said valve members to a first position relative to each other and effective to seal off said flow path, said valve members being adapted, in response to an increase in fluid pressure on said one side of said valve relative to the fluid pressure on the other side of said valve, to have relative movement to a second relative position effective to open said flow path.

Claim 4

The control valve of claim 2, wherein said biasing means comprises first and second spring means adapted respectively to bias said first and second valve members in opposite directions.

Claim 5

The control valve of claim 2, wherein said sealing means comprises a single valve seat on one of said valve members and sealingly engaged by the other of said valve member.

Claim 6

The control valve of claim 4, wherein said sealing means further comprises gasket means carried by the other of said valve members and wherein said single valve seat in its normal position bears on said gasket means, thereby closing said flow path.

Claim 7

The control valve of claim 2, wherein said means for defining said flow path includes aperture means in at least said first valve member, said restriction being defined at least in part by said aperture means.

Claim 8

The control valve of clam 6 further comprising means for increasing the cross-sectional flow area of said restriction as said first and second valve members move away from each other.

Claim 9

The control valve of clam 6 further comprising means for increasing the cross-sectional flow area of said restriction as said first and second valve members move away from each other.

Claim 10

The control valve of claim 2 further comprising fluid cutoff means adapted to cut off the flow of fluid through said valve when said first and second valve members move away from each other, a predetermined distance.

Claim 11

The control valve of claim 1 wherein said means for defining said flow path includes aperture means in at least said first valve member, said restriction being defined at least in part by said aperture means.

Claim 12

The control valve of claim 2, in which said chamber is defined in part by a movable valve member, said member in moving from said first to said second position causing said chamber to enlarge, thereby further to reduce the fluid pressure on said one side of said sealing means.

Claim 13

A control valve for maintaining the pressure of a fluid on one side of said valve substantially at the same level as the pressure of the fluid on the other side of said valve, compRising first and second valve members communicating respectively with the fluid on opposite sides of said valve and defining a path for the flow of fluid through said valve from one side to the other side of said valve, means operatively connected to said first and second valve members for normally sealing off said flow path to prevent the flow of fluid through said valve and adapted to open said flow path in response to an increase in pressure on one side of said sealing means relative to the other side of said sealing means, means defining a restriction in said flow path adjacent said one side of said sealing means and comprising a substantial portion of the length of said flow path, said restriction being effective upon the flow of fluid therethrough to create a pressure drop thereacross, thereby to reduce the fluid pressure adjacent said one side of said sealing means, whereby said sealing means upon opening a flow path of greater cross section than said restriction means, is caused to return to its normally closed position, further comprising said valve members being mounted for relative movement, and means normally biasing said valve members to a first position relative to each other and effective to seal off said flow path, said valve members adapted, in response to an increase in fluid pressure on one side of said valve relative to the fluid pressure on the other side of said valve, to move away from each other to a second relative position effective to open said flow path, wherein said means for defining said flow path includes aperture means in at least said first valve member, said restriction being defined at least in part by said aperture means, further comprising a third valve member extending from and movable with said second valve member, said aperture in said first valve member adapted to receive said third valve member forming an annular clearance between said aperture and said third valve member, said annular clearance defining said flow path restriction.

Claim 14

A control valve for maintaining the pressure of a fluid on one side of said valve substantially at the same level as the pressure of the fluid on the other side of said valve, compRising first and second valve members communicating respectively with the fluid on opposite sides of said valve and defining a path for the flow of fluid through said valve from one side to the other side of said valve, means operatively connected to said first and second valve members for normally sealing off said flow path to prevent the flow of fluid through said valve and adapted to open said flow path in response to an increase in pressure on one side of said sealing means relative to the other side of said sealing means, means defining a restriction in said flow path adjacent said one side of said sealing means and comprising a substantial portion of the length of said flow path, said restriction being effective upon the flow of fluid therethrough to create a pressure drop thereacross, thereby to reduce the fluid pressure adjacent said one side of said sealing means, whereby said sealing means upon opening a flow path of greater cross section than said restriction means, is caused to return to its normally closed position, further comprising said valve members being mounted for relative movement, and means normally biasing said valve members to a first position relative to each other and effective to seal off said flow path, said valve members adapted, in response to an increase in fluid pressure on one side of said valve relative to the fluid pressure on the other side of said valve, to move away from each other to a second relative position effective to open said flow path, wherein said means for defining said flow path includes aperture means in at least said first valve member, said restriction being defined at least in part by said aperture means, further comprising a third valve member extending from and movable with said second valve member, said aperture in said first valve member adapted to receive said third valve member forming an annular clearance between said aperture and said third valve member, said annular clearance defining said flow path restriction.

Claim 15

The control valve of claim 11 wherein said stop means extends from and is movable with said third valve member.

Claim 16

The control valve of claim 11 further comprising fluid cutoff means operatively connected to said third valve member and adapted to close off said restriction when said first and second valve members move away from each other a predetermined distance.

Claim 17

A control valve for maintaining the pressure of the fluid on one side of said valve substantially at the same level as the pressure of the fluid on the other side of said valve, comprising valve support means, first and second valve members supported by said valve support means and movable relative thereto and relative to each other, said valve members defining a flow path for the flow of fluid through said valve, means normally biasing said valve members to a first position relative to each other effective to seal off said flow path, said valve members being adapted in response to an increase in fluid pressure on the other side of said valve to move relative to each other to a second relative position effective to open said flow path, means for allowing said valve members to move together a substantial distance in response to said increase in fluid pressure on one side of said valve, and stop means effective to stop the movement of one of said valve members after said movement together a substantial distance, whereby the other of said valve members continues its movement relative to said support and moves relative to said one valve member to said second relative position, thereby to open said fluid path, further comprising fluid cutoff means adapted to cut off the flow of fluid through said valve when said first and second valve members move away from each other, a predetermined distance.

Claim 18

A control valve for maintaining the pressure of the fluid on one side of said valve substantially at the same level as the pressure of the fluid on the other side of said valve, comprising valve support means, first and second valve members supported by said valve support means and movable relative thereto and relative to each other, said valve members defining a flow path for the flow of fluid through said valve, means normally biasing said valve members to a first position relative to each other effective to seal off said flow path, said valve members being adapted in response to an increase in fluid pressure on the other side of said valve to move relative to each other to a second relative position effective to open said flow path, means for allowing said valve members to move together a substantial distance in response to said increase in fluid pressure on one side of said valve, and stop means effective to stop the movement of one of said valve members after said movement together a substantial distance, whereby the other of said valve members continues its movement relative to said support and moves relative to said one valve member to said second relative position, thereby to open said fluid path, further comprising fluid cutoff means adapted to cut off the flow of fluid through said valve when said first and second valve members move away from each other, a predetermined distance.

Claim 19

A control valve for maintaining the pressure of a fluid on one side of said valve substantially at the same level as the pressure of the fluid on the other side of said valve, comprising a housing, a first valve member sealingly and slidably Mounted on said housing and urged by first spring means, against said housing in a first direction, a second valve member sealingly and slidably mounted on said first valve member and urged by second spring means toward and into engagement with said first valve member in a second direction opposite to said first direction, said housing having first aperture means on said one side of said valve for providing fluid communication between said first valve member and the fluid on said one side of said valve and having second aperture means on the other side of said valve for providing fluid communication between said second valve member and the fluid on said other side of said valve, said first and second valve members being provided respectively with third and fourth aperture means, sealing means carried by one of said valve members and normally operatively engaged by the other of said valve members between said third and fourth apertures for sealing off a flow path therebetween, and plug means extending from said second valve member in said second direction and received within and extending through and beyond said third aperture means, the extended portion of said plug means adapted to engage said housing, the clearance between said plug means and said third aperture means defining a restricted flow path whereby upon the increase in relative fluid pressure on said one side of said valve, said second valve member is urged to move in said first direction away from said first valve member to separate said sealing means from said other of said valve members, and whereby upon the increase of relative fluid pressure on said other side of said valve, said first and second valve members are urged to move together in said second direction until said plug means engages said housing, whereupon said second valve member remains stationary with respect to said housing and said first valve member continues its movement in said second direction, again to separate from said other of said valve members.

Claim 20

A control valve for maintaining the pressure of a fluid on one side of said valve substantially at the same level as the pressure of the fluid on the other side of said valve, comprising a housing, a first valve member sealingly and slidably Mounted on said housing and urged by first spring means, against said housing in a first direction, a second valve member sealingly and slidably mounted on said first valve member and urged by second spring means toward and into engagement with said first valve member in a second direction opposite to said first direction, said housing having first aperture means on said one side of said valve for providing fluid communication between said first valve member and the fluid on said one side of said valve and having second aperture means on the other side of said valve for providing fluid communication between said second valve member and the fluid on said other side of said valve, said first and second valve members being provided respectively with third and fourth aperture means, sealing means carried by one of said valve members and normally operatively engaged by the other of said valve members between said third and fourth apertures for sealing off a flow path therebetween, and plug means extending from said second valve member in said second direction and received within and extending through and beyond said third aperture means, the extended portion of said plug means adapted to engage said housing, the clearance between said plug means and said third aperture means defining a restricted flow path whereby upon the increase in relative fluid pressure on said one side of said valve, said second valve member is urged to move in said first direction away from said first valve member to separate said sealing means from said other of said valve members, and whereby upon the increase of relative fluid pressure on said other side of said valve, said first and second valve members are urged to move together in said second direction until said plug means engages said housing, whereupon said second valve member remains stationary with respect to said housing and said first valve member continues its movement in said second direction, again to separate from said other of said valve members.

Claim 21

The control valve of claim 15 wherein said plug member is tapered inwardly on a portion of its surface remote from said second valve member, whereby as said valve members move away from each other, said flow restriction defined by said clearance between said plug and said third aperture means is progressively widened.

Claim 22

The control valve of claim 16 wherein said sealing means comprises a single valve seat formed on said second valve member and a gasket operatively connected to said first valve member adjacent to and surrounding said third aperture means.

Claim 23

The control valve of claim 15 wherein said sealing means comprises a single valve seat formed on said second valve member and a gasket operatively connected to said first valve member adjacent to and surrounding said third aperture means.