Moisture and pressure sensitive fluid control circuit

Claim 2

A moisture and pressure sensitive fluid flow control system comprising: controller body means defining first, second and third chambers, a control valve port communicating with the first chamber, a controller outlet, and a controller outlet passageway connecting the outlet with the second chamber; a first movable diaphragm assembly separating and defining a diaphragm passageway between the first and second chambers, the passageway having an end which opens into the second chamber, and the assembly being constructed to provide a valve seat at the end; first diaphragm biasing means for urging the first movable diaphragm means toward the first chamber; a second movable diaphragm assembly separating the second and third chambers and including a valve closing member; and in communicating with the third chamber, fluid detection means adapted to apply a closing force so as to move the second movable diaphragm assembly such that the valve closing member seats in the valve seat when sufficient fluid is present in a region to be sensed for fluid; the system being constructed such that, in the absence of sufficient fluid in the region to be sensed, fluid is allowed to flow from the control valve port to the controller outlet via the controller outlet passageway.

Claim 3

The system of claim 1 further comprising valve means in the outlet passageway, the valve means being openable by movement of the first diaphragm assembly in the direction urged by the first diaphragm biasing means.

Claim 4

The system of claim 1 wherein the fluid detection means comprises a porous element adapted to be placed in moisture transfer relationship with a medium in a region where moisture status is to be sensed.

Claim 5

The system of claim 3 wherein the porous element fluidly communicates with said third chamber.

Claim 6

The system of claim 3 wherein the porous element is an elongated tensiometer probe projecting outwardly from said controller body means.

Claim 7

The system of claim 3 wherein the porous element is a plate which fits against said controller body means.

Claim 8

The system of claim 3 further comprising diaphragm biasing means for urging the second movable diaphragm assembly toward a position where the valve closing member seats in the valve seat.

Claim 9

The system of claim 1 wherein the fluid detection means comprises an open vessel located above the second movable diaphragm assembly so that the closing force is applied by the action of gravity on liquid in the vessel.

Claim 10

The system of claim 8 further comprising second diaphragm biasing means for urging the second movable diaphragm assembly toward a position where the valve closing member is removed from the valve seat.

Claim 11

The system of claim 1 wherein: the body defines a second outlet passageway between the outlet and the second chamber; and a one way valve is provided in the second outlet passageway to allow fluid flow from the outlet to the atmosphere.

Claim 12

The system of claim 1 further comprising a flow control valve having a body which defines an inlet for connection to a source of pressurized fluid, a primary outlet and a venting outlet, and means for opening or closing the primary outlet automatically through the release or application of fluid pressure, respectively, to the venting outlet, said venting outlet being in fluid-tight communication with the control valve port of the controller.

Claim 13

The system of claim 11 further comprising: means defining a fluid transfer passageway for connecting the source of pressurized fluid to the control valve venting outlet and the control valve port of the controller; and flow-restricting means, provided in the passageway, to restrict flowing of pressurized fluid through the passageway to the venting outlet 86 of the control valve and the control valve port 20 of the controller.

Claim 14

The system of claim 12 wherein the flow-restricting means comprises a valve suitable to allow fluid to flow at a constant slow rate over a wide range of upstream pressures.

Claim 15

The system of claim 12 wherein the flow-restricting means comprises at least a region of the passageway with a cross-sectional area sufficiently small to limit the rate at which fluid can flow through the passageway.

Claim 16

The system of claim 1 further comprising pressure release means for selectively venting pressure from the first chamber.

Claim 17

The system of claim 15 wherein the pressure release means comprises: a pressure release outlet from the first chamber to atmosphere; and a removable plug for selectively sealing said pressure release outlet.

Claim 18

The system of claim 1 further comprising set point adjustment means.

Claim 19

The system of claim 17 wherein the set point adjustment means comprises a chamber communicating with the controller outlet for selectively varying an outlet height of the controller.

Claim 20

The system of claim 1 further comprising stop means to limit travel of the first movable diaphragm assembly in the direction urged by the first diaphragm biasing means.

Claim 21

The system of claim 1 wherein: the diaphragm passageway has an end which opens into the first chamber; the first movable diaphragm assembly is constructed to provide a valve seat at the end which opens into the first chamber; and a valve closing member is provided in the first chamber to mate with the valve seat at the end which opens into the first chamber.

Claim 22

The system of claim 20 further comprising means for adjusting the position of the valve closing member in the first chamber with respect to the position of at least a part of the first diaphragm biasing means.

Claim 23

The system of claim 1 further comprising pressure application means for selectively applying pressure to the second chamber.

Claim 24

A moisture-sensitive liquid flow control system comprising: controller body means defining first, second and third chambers, a control valve port communicating with the first chamber, a controller outlet, and a controller outlet passageway connecting the outlet with the second chamber; a first movable diaphragm assembly separating and defining a diaphragm passageway between the first and second chambers, the ends of the diaphragm passageway being first chamber and second chamber valve seats respectively; a first valve closing member within the first chamber; first diaphragm biasing means for urging the first movable diaphragm means such that the first valve closing member seats in the first valve chamber seat; a second movable diaphragm assembly separating the second and third chambers and including a second valve closing member; valve means in the outlet passageway, the valve means being openable by movement of the first diaphragm assembly in the direction urged by the first diaphragm biasing means; and in communication with the third chamber, moisture detection means adapted to apply a closing force to move the second movable diaphragm assembly such that the second valve closing member seats in the second valve chamber seat when moisture is present in a region to be sensed for moisture.

Claim 25

A moisture-sensitive liquid flow control system comprising: controller body means defining first, second and third chambers, a control valve port communicating with the first chamber, a controller outlet, and a controller outlet passageway connecting the outlet with the second chamber; a first movable diaphragm assembly separating and defining a diaphragm passageway between the first and second chambers, the ends of the diaphragm passageway being first chamber and second chamber valve seats respectively; a first valve closing member within the first chamber; first diaphragm biasing means for urging the first movable diaphragm means such that the first valve closing member seats in the first valve chamber seat; a second movable diaphragm assembly separating the second and third chambers and including a second valve closing member; valve means in the outlet passageway, the valve means being openable by movement of the first diaphragm assembly in the direction urged by the first diaphragm biasing means; and in communication with the third chamber, moisture detection means adapted to apply a closing force to move the second movable diaphragm assembly such that the second valve closing member seats in the second valve chamber seat when moisture is present in a region to be sensed for moisture.

Claim 26

The system of claim 23 wherein the moisture detection means comprises a porous element adapted to be placed in moisture transfer relationship with soil in a region where moisture is to be sensed.

Claim 27

The device of claim 23 further comprising second diaphragm biasing means for urging the second movable diaphragm assembly toward a position where the second valve closing member seats in the second valve chamber seat.

Claim 28

The system of claim 23 wherein the moisture detection means comprises an open vessel located above the second movable diaphragm assembly so that the closing force is applied by the action of gravity on liquid in the vessel.

Claim 29

The system of claim 26 further comprising second diaphragm biasing means for urging the second movable diaphragm assembly toward a position where the second valve closing member is removed from the second valve chamber seat.

Claim 30

The system of claim 23 wherein: the body defines a second outlet passageway between the outlet and the second chamber; and a one way valve is provided in the second outlet passageway to allow liquid flow from the outlet into the second chamber.

Claim 31

The system of claim 23 further comprising a flow-restricting valve means or passageway separating a source of fluid pressure from both the venting outlet of the control valve, and the control valve port of the controller.