Moisture responsive apparatus for controlling moisture content of soil

Claim 2

A moisture responsive sensor unit comprising: a tubular moisture responsive sensing element having a first end and a second end, said sensing element being expansible longitudinally as a function of the amount of moisture absorbed by said element; and an actuator, at least a portion of which is disposed within said sensing element, having a first end coupled to the first end of said sensing element and a second end, the dimensions of said actuator being substantially unaffected by moisture, said second ends of said sensing element and said actuator being adapted to be coupled to relatively displaceable portions of a hydraulic control signal generating means.

Claim 3

A moisture responsive sensor unit, as defined in claim 1, in which: said tubular sensing element has a thin, perforated wall, said perforations exposing the interior surface of said sensing element to substantially the same moisture levels as the exterior surface thereof.

Claim 4

A moisture responsive sensor unit, as defined in claim 2, in which: said tubular sensing element and actuator define an annular space between them, absorbent material substantially filling said annular space.

Claim 5

A moisture responsive sensor unit, as defined in claim 2, in which: said tubular sensing element is fabricated of a material from the group consisting of nylon, cellulose acetate and vulcanized fiber.

Claim 6

A moisture responsive sensor unit, as defined in claim 1, in which: said tubular sensing element comprises a plurality of sensing tubes disposed in concentric relationship, the innermost tube including said first end and the outermost tUbe including said second end, adjacent tubes being separated by tubular support means unaffected dimensionally to moisture, said support means being connected to opposed ends of adjacent sensor tubes whereby the total relative displacement of said portions of said control signal generating means is increased in relation to the number of sensor tubes employed.

Claim 7

A moisture responsive sensor unit, as defined in claim 1, in which: said sensing element has reinforcements comprising a plurality of spaced ribs projecting from the external surface of said elements.

Claim 8

A moisture responsive sensor unit, as defined in claim 1, in which: the position of said actuator is adjustable relative to said sensing element to predetermine the relative positions of said second ends.

Claim 9

A moisture responsive sensor unit, as defined in claim 1, in which: said sensing element and said actuator having substantially the same coefficients of thermal expansion.

Claim 10

A moisture responsive control device comprising: a tubular element adapted to be placed in proximity to the material whose moisture content is to be controlled, said element being expansible in relation to said moisture content and having first and second ends; a reference element having a first end attached to said first end of said tubular element, and a second end, said reference element being substantially unaffected dimensionally by moisture; and pilot valve means for controlling a moisture addition system and having relatively movable pilot valve portions, one of said pilot valve portions being secured to the second end of said tubular element and the other of said pilot valve portions being secured to the second end of said reference element, expansion and contraction of said tubular element relative to said reference element operating said pilot valve means between open and closed positions.

Claim 11

A moisture responsive control device comprising: a tubular element adapted to be placed in proximity to the material whose moisture content is to be controlled, said element being expansible in relation to said moisture content and having first and second ends; a reference element having a first end attached to said first end of said tubular element, and a second end, said reference element being substantially unaffected dimensionally by moisture; and pilot valve means for controlling a moisture addition system and having relatively movable pilot valve portions, one of said pilot valve portions being secured to the second end of said tubular element and the other of said pilot valve portions being secured to the second end of said reference element, expansion and contraction of said tubular element relative to said reference element operating said pilot valve means between open and closed positions.

Claim 12

A moisture responsive control device, as defined in claim 9, in which: said tubular element is perforated to expose the inner wall surface of said tubular element to said moisture thereby decreasing the reaction time of said element.

Claim 13

A moisture responsive control device, as defined in claim 9, in which: said reference element is disposed within said tubular element.

Claim 14

A moisture responsive control device, as defined in claim 9, in which: said device includes a moisture-permeable screen disposed about said tubular element but out of contact therewith to define an annular space about said tubular element and isolate said element from direct contact with the material whose moisture content is to be controlled.

Claim 17

A device, as defined in claim 13, in which: said tubular sensing element is perforated to expose the interior surface of said element to essentially the same moisture level as the exterior surface of said element.

Claim 18

A device, as defined in claim 14, said tubular sensing element and member define an annular space between them, said space being substantially filled with a moisture absorbing material.

Claim 25

A moisture responsive device for controlling the operation of a soil irrigation system, comprising: a pilot valve comprising a pilot valve body enclosing a movable valve element, said pilot valve having an inlet for connection to a supply of water under pressure and an outlet for providing a hydraulic pressure control signal, said valve element being disposed in conduit means interconnecting said inlet and outlet, said valve element being normally biased to a position interrupting communication between said inlet and outlet; and a moisture sensor for operating said pilot valve, said sensor including (i) a tubular sensing element having a first end and a second end and adapted to be disposed in moisture-sensing relationship with said soil and expansible longitudinally in relation to the moisture content of said soil, said second end being secured to said pilot valve body, and (ii) an actuator, dimensionally stable in the presence of moisture, disposed at least partially within said tubular sensing element and having a first end coupled to said first end of said sensing element and a second end in operative relationship with said movable valve element, contraction of said sensing element to a predetermined length causing said valve element to be moved by said actuator to establish communication between said inlet and outlet.

Claim 26

A moisture responsive device for controlling the operation of a soil irrigation system, comprising: a pilot valve comprising a pilot valve body enclosing a movable valve element, said pilot valve having an inlet for connection to a supply of water under pressure and an outlet for providing a hydraulic pressure control signal, said valve element being disposed in conduit means interconnecting said inlet and outlet, said valve element being normally biased to a position interrupting communication between said inlet and outlet; and a moisture sensor for operating said pilot valve, said sensor including (i) a tubular sensing element having a first end and a second end and adapted to be disposed in moisture-sensing relationship with said soil and expansible longitudinally in relation to the moisture content of said soil, said second end being secured to said pilot valve body, and (ii) an actuator, dimensionally stable in the presence of moisture, disposed at least partially within said tubular sensing element and having a first end coupled to said first end of said sensing element and a second end in operative relationship with said movable valve element, contraction of said sensing element to a predetermined length causing said valve element to be moved by said actuator to establish communication between said inlet and outlet.

Claim 27

A device, as defined in claim 19, in which: said sensing element and said actuator have substantially the same coefficient of thermal expansion.

Claim 28

A device, as defined in claim 19, in which: said sensing element is made of a material selected from the group consisting of nylon, cellulose acetate and vulcanized fiber.

Claim 29

A device, as defined in claim 19, in which: said tubular sensiNg element and said actuator define an annular space between them, said tubular sensing element being perforated to conduct moisture to and from said annular space, an absorbent material substantially filling said annular space.

Claim 30

A device, as defined in claim 19, in which: said device further includes a moisture-permeable screen disposed about said tubular sensing element but out of contact therewith to define an annular, soil isolation space about said sensing element.

Claim 31

A device, as defined in claim 19, in which: said actuator is adjustably coupled to said sensing element whereby the points at which said pilot valve opens and closes may be preadjusted.

Claim 32

A device, as defined in claim 19, in which: said sensing element comprises a plurality of concentric, coextensive, perforated sensing tubes, adjacent sensing tubes being connected to a perforated support tube dimensionally unaffected by moisture and interposed between said adjacent tubes, alternate ends of adjacent tubes being connected to said interposed support tube, whereby the movement of said actuator relative to said second end of said sensing element is amplified in accordance with the number of sensing tubes employed.

Claim 33

A device, as defined in claim 25, in which: said sensing tubes, each support tube and said actuator have substantially the same coefficient of thermal expansion.

Claim 34

A device, as defined in claim 19, in which: said movable pilot valve element comprises a ball element and said second end of said actuator includes a hollow push rod having a port in the side wall thereof and a tip adapted to engage said ball element, said pilot valve body having a vent, withdrawal of said push rod tip from said ball element bringing said outlet in said pilot valve body into communication with said vent through said hollow push rod and port.

Claim 35

A device, as defined in claim 19, in which said tubular sensing element has reinforcing ribs projecting from the exterior surface thereof.

Claim 36

Apparatus for automatically controlling the moisture content of soil comprising: valve means operable by a small volume, hydraulic pressure control signal to supply water to a system for irrigating said soil; a pilot valve coupled to said valve means, said pilot valve being adapted to selectively provide said control flow from a source of pressurized water; and means coupled to said pilot valve for operating said pilot valve, said last-mentioned means including a moisture sensor unit adapted to be placed in moisture sensing relationship to said soil, said unit comprising (i) a tubular sensing element expandable longitudinally as a function of the amount of moisture absorbed by said sensing element and (ii) a member coupled to said sensing element and at least partially enclosed thereby, said member being substantially unaffected dimensionally by moisture, predetermined variations in the length of said sensing element relative to said member operating said pilot valve.

Claim 37

Apparatus for automatically controlling the moisture content of soil comprising: valve means operable by a small volume, hydraulic pressure control signal to supply water to a system for irrigating said soil; a pilot valve coupled to said valve means, said pilot valve being adapted to selectively provide said control flow from a source of pressurized water; and means coupled to said pilot valve for operating said pilot valve, said last-mentioned means including a moisture sensor unit adapted to be placed in moisture sensing relationship to said soil, said unit comprising (i) a tubular sensing element expandable longitudinally as a function of the amount of moisture absorbed by said sensing element and (ii) a member coupled to said sensing element and at least partially enclosed thereby, said member being substantially unaffected dimensionally by moisture, predetermined variations in the length of said sensing element relative to said member operating said pilot valve.

Claim 38

Apparatus, as defined in claim 29, in which: said valve means includes a hydraulic switch and an irrigation system shutoff valve, said switch having a pressure responsive element responsive to said hydraulic control signal, an inlet for connection through said shutoff valve to a supply of pressurized water and a vent, said pressure responsive element normally interrupting communication between said inlet and vent, said shutoff valve having an inlet adapted for connection to said pressurized supply, a first outlet adapted for connection to said hydraulic switch inlet, a second outlet adapted for connection to said irrigation system and pressure responsive means normally interrupting communication between said inlet and second outlet of said shutoff valve, the presence of said control signal displacing said pressure responsive element of said switch to establish communication between said inlet and vent of said shutoff valve to create a pressure imbalance across said pressure responsive elEment of said shutoff valve whereby communication between said inlet and second outlet of said shutoff valve is established.

Claim 39

Apparatus, as defined in claim 29, in which: said member comprises a housing having a bore adapted to be coupled to said source of pressurized water and carrying said valve means and pilot valve and wherein said pilot valve has a movable valve element and said sensing element has a free end movable relative to said housing in accordance with the moisture absorbed by said element, said free end being adapted to displace said movable valve element upon contraction of said sensing element to a predetermined length and establish said control signal.

Claim 40

Apparatus, as defined in claim 29, in which: said pilot valve comprises a pilot valve body enclosing a movable valve element, said pilot valve body having an inlet for connection to said source of pressurized water and an outlet for providing said hydraulic control signal, displacement of said movable valve element selectively establishing communication between said inlet and outlet and wherein said member comprises an actuator rod having a portion adapted to displace said movable element.

Claim 41

Apparatus, as defined in claim 29, in which: said tubular sensing element and said member are adjustably coupled.

Claim 42

Apparatus, as defined in claim 29, in which: said sensing element and said member have substantially the same coefficient of thermal expansion.

Claim 43

Apparatus, as defined in claim 29, in which: said sensing element has interior and exterior surfaces and is perforated to expose said interior surface to substantially the same moisture levels as the exterior surface.

Claim 44

Apparatus, as defined in claim 35, in which: said sensing element and said member define between them an annular space, said space containing absorbent material.

Claim 45

Apparatus, as defined in claim 29, in which: said moisture sensing unit further includes a moisturepermeable screen disposed about said tubular sensing element to define an annular soil isolation space about said sensing element.

Claim 46

A moisture responsive, soil irrigating apparatus comprising: a cylindrical housing substantially unaffected dimensionally by moisture, said housing having an internal, longitudinally extending bore, an upper end and a lower end, said lower end being adapted for connection to a supply of pressurized water, said housing further including a vent opening; a perforated, tubular moisture sensing element disposed about said housing in concentric relationship therewith, said tubular element having an upper end adjustably secured to the upper end of said housing and a lower, free end, said sensing element being expandable longitudinally as a function of the amount of moisture absorbed by said sensing element; a pilot valve carried by said housing within said bore, said pilot valve including a movable ball valve element and a longitudinally extending, hollow push rod having (i) a port in the side wall thereof, (ii) an upper tip adapted to engage and displace said ball element off a seat and (iii) a lower end connected to the lower, free end of said sensing element, said push rod being movable vertically relative to said housing in response to the longitudinal expansion and contraction of said sensing element, said pilot valve including a cavity below said ball valve element; a shutoff valve carried in said bore of said housing, said shutoff valve including a piston movable in a guide block, said piston and guide block defining between them an upper chamber in said bore, said shutoff valve and pilot valve defining between them a lower chamber in said bore, said lower chamber being in continuous communication with said lower end of said housing, a conduit connecting said cavity in said pilot valve and said upper chamber, unseating of said ball valve element establishing communication between said lower chamber and said cavity; and a pop-up sprinkler head carried in The upper portion of said bore above said shutoff valve, contraction of said sensing element to a predetermined length unseating said ball element to open said pilot valve and said shutoff valve to establish communication between said upper portion of said bore and said lower chamber whereby said sprinkler head is raised and water discharged therefrom, elongation of said sensing element to a predetermined length closing said pilot valve, further elongation of said sensing element causing withdrawal of said push rod from said ball element and establishing communication between said passage and said vent opening via said port and hollow interior of said push rod whereby water in said passage is vented and depressurized, said shutoff valve thereby closing to terminate the sprinkling cycle.

Claim 47

A moisture responsive, soil irrigating apparatus comprising: a cylindrical housing substantially unaffected dimensionally by moisture, said housing having an internal, longitudinally extending bore, an upper end and a lower end, said lower end being adapted for connection to a supply of pressurized water, said housing further including a vent opening; a perforated, tubular moisture sensing element disposed about said housing in concentric relationship therewith, said tubular element having an upper end adjustably secured to the upper end of said housing and a lower, free end, said sensing element being expandable longitudinally as a function of the amount of moisture absorbed by said sensing element; a pilot valve carried by said housing within said bore, said pilot valve including a movable ball valve element and a longitudinally extending, hollow push rod having (i) a port in the side wall thereof, (ii) an upper tip adapted to engage and displace said ball element off a seat and (iii) a lower end connected to the lower, free end of said sensing element, said push rod being movable vertically relative to said housing in response to the longitudinal expansion and contraction of said sensing element, said pilot valve including a cavity below said ball valve element; a shutoff valve carried in said bore of said housing, said shutoff valve including a piston movable in a guide block, said piston and guide block defining between them an upper chamber in said bore, said shutoff valve and pilot valve defining between them a lower chamber in said bore, said lower chamber being in continuous communication with said lower end of said housing, a conduit connecting said cavity in said pilot valve and said upper chamber, unseating of said ball valve element establishing communication between said lower chamber and said cavity; and a pop-up sprinkler head carried in The upper portion of said bore above said shutoff valve, contraction of said sensing element to a predetermined length unseating said ball element to open said pilot valve and said shutoff valve to establish communication between said upper portion of said bore and said lower chamber whereby said sprinkler head is raised and water discharged therefrom, elongation of said sensing element to a predetermined length closing said pilot valve, further elongation of said sensing element causing withdrawal of said push rod from said ball element and establishing communication between said passage and said vent opening via said port and hollow interior of said push rod whereby water in said passage is vented and depressurized, said shutoff valve thereby closing to terminate the sprinkling cycle.

Claim 48

A moisture responsive sensor unit, comprising: an elongated moisture sensing element adapted to expand in accordance with increasing amounts of moisture and to contract in accordance with reducing amounts of moisture thereat, and an elongated actuator having one end coupled to an end of said sensing element for movement therewith, the dimensions of said actuator being substantially unaffected by moisture whereby the amount of moisture present at said sensing element is indicated by the relative displacement of the free ends of said sensing element and said actuator, said sensing element being fabricated of a material from the group consisting of nylon, cellulose acetate and vulcanized fiber.

Claim 49

A moisture responsive sensor unit, comprising: an elongated moisture sensing element adapted to expand in accordance with increasing amounts of moisture and to contract in accordance with reducing amounts of moisture thereat, and an elongated actuator having one end coupled to an end of said sensing element for movement therewith, the dimensions of said actuator being substantially unaffected by moisture whereby the amount of moisture present at said sensing element is indicated by the relative displacement of the free ends of said sensing element and said actuator, said sensing element being fabricated of a material from the group consisting of nylon, cellulose acetate and vulcanized fiber.

Claim 50

A moisture responsive sensor unit as described in claim 39 and wherein said free ends of said sensing element and said actuator are operatively connected to a means for generating a hydraulic signal in accordance with said relative displacement of said free ends.

Claim 51

A moisture responsive sensor unit as described in claim 39 and wherein said sensing element has a thin wall formed to permit access of the moisture to both sides thereof.

Claim 52

A moisture responsive sensor unit as described in claim 41 and wherein said wall has a thickness of from about 0.010 inch to about 0.012 inch.

Claim 53

A moisture responsive sensor unit as described in claim 39 and wherein said actuator is fabricated of a material from the group consisting of polycarbonate, polystyrene, polyurethane, polypropelene, chlorinated polyether, and polyvinyl chloride.

Claim 54

A moisture responsive sensor unit as described in claim 39 and wherein means is provided in the coupling between said sensing element and said actuator for adjusting said relative displacement of their said free ends.

Claim 55

A moisture responsive sensor unit as described in claim 40 and wherein said sensing element and said actuator are fabricated of materials having substantially the same coefficients of thermal expansion whereby said relative displacement of said free ends thereof in accordance with the amount of moisture present is substantially unaffected by temperature.

Claim 56

A moisture responsive sensor unit as described in claim 40 and wherein said sensing element and said actuator and said means for generating a hydraulic signal are incorporated in a unitary assembly.

Claim 57

A moisture responsive sensor unit as described in claim 40 and wherein said means for generating a hydraulic signal is connected to a hydraulic actuator capable of operation in response to said hydraulic signal.

Claim 58

A moisture responsive sensor unit as described in claim 47 and wherein said hydraulic actuator is coupled to an irrigation valve and sprinkler means so as to open said valve and supply water to said sprinkler when moisture at said sensing element falls below a predetermined amount, and to close said valve when moisture at said sensing element exceeds a predetermined amount.

Claim 59

A moisture responsive sensor unit as described in claim 48 and wherein said hydraulic actuator is formed to cause rapid opening and closing of said valve.

Claim 60

A moisture responsive sensor unit as described in claim 39 and wherein said hydraulic generating Means comprises pilot valve means adapted for connection to a source of fluid under pressure and having relatively movable valve member and valve seat portions, one of said portions being operatively connected to said free end of said sensing element for movement therewith, and the other of said portions being operatively connected to said free end of said actuator for movement therewith.

Claim 61

Automatic demand soil irrigation apparatus, comprising a sprinkler valve adapted for connection to a source of water under pressure, a sprinkler connected to said sprinkler valve to be supplied water therefrom when the latter is open, a hydraulic actuator operatively connected to open and close said sprinkler valve, a pilot valve adapted for connection to the source of water under pressure and to said hydraulic actuator for selectively supplying water under pressure thereto to open said sprinkler valve and for venting water therefrom to close said sprinkler valve, and a moisture sensor unit adapted to be placed in moisture sensing relationship with the soil and operatively connected to said pilot valve for controlling same.

Claim 62

Automatic demand soil irrigation apparatus, comprising a sprinkler valve adapted for connection to a source of water under pressure, a sprinkler connected to said sprinkler valve to be supplied water therefrom when the latter is open, a hydraulic actuator operatively connected to open and close said sprinkler valve, a pilot valve adapted for connection to the source of water under pressure and to said hydraulic actuator for selectively supplying water under pressure thereto to open said sprinkler valve and for venting water therefrom to close said sprinkler valve, and a moisture sensor unit adapted to be placed in moisture sensing relationship with the soil and operatively connected to said pilot valve for controlling same.

Claim 63

Automatic demand soil irrigation apparatus as described in claim 51 and wherein said moisture responsive sensor unit comprises an elongated moisture sensing element adapted to expand in accordance with increasing amounts of moisture and to contract in accordance with reducing amounts of moisture thereat, and an elongated actuator having one end coupled to an end of said sensing element for movement therewith, the dimensions of said actuator being substantially unaffected by moisture whereby the amount of moisture present at said sensing element is indicated by the relative displacement of the free ends of said sensing element and said actuator.

Claim 64

Automatic demand soil irrigation apparatus as described in claim 51 and wherein said moisture responsive sensor unit comprises: a tubular moisture responsive sensing element having a first end and a second end, said sensing element being expandible longitudinally as a function of the amount of moisture absorbed by said element; and an actuator, at least a portion of which is disposed within said sensing element, having a first end coupled to the first end of said sensing element, and a second end, the dimensions of said actuator being substantially unaffected by moisture, said second ends of said sensing element and said actuator being adapted to be coupled to relatively displaceable portions of a hydraulic control signal generating means.

Claim 65

A pilot valve construction, comprising a housing providing a chamber adapted for connection to a source of liquid under pressure, a valve seat across an end of said chamber, a ball valve member movable in said chamber toward and away from said valve seat, a tubular stem slidably mounted in said housing for axial movement to displace said ball from said seat, and spring means urging said ball against said seat, said housing having a first passage downstream of said valve seat and adapted for connection to a hydraulic device for transmitting liquid under pressure thereto when said ball is displaced from said seat, said housing having a second passage adapted for venting liquid therefrom, said tubular stem being formed for blocking off said second passage when said stem is displacing said ball from said valve seat and having an opening therethrough for communicating said first passage with said second passage when said stem is not displacing said ball from said valve seat.

Claim 66

A pilot valve construction, comprising a housing providing a chamber adapted for connection to a source of liquid under pressure, a valve seat across an end of said chamber, a ball valve member movable in said chamber toward and away from said valve seat, a tubular stem slidably mounted in said housing for axial movement to displace said ball from said seat, and spring means urging said ball against said seat, said housing having a first passage downstream of said valve seat and adapted for connection to a hydraulic device for transmitting liquid under pressure thereto when said ball is displaced from said seat, said housing having a second passage adapted for venting liquid therefrom, said tubular stem being formed for blocking off said second passage when said stem is displacing said ball from said valve seat and having an opening therethrough for communicating said first passage with said second passage when said stem is not displacing said ball from said valve seat.

Claim 67

In an irrigation system having a supply conduit for water under pressure, a slave valve mounted in said conduit for controlling the flow of water therethrough, a hydraulic actuator for said slave valve, a pilot valve formed for selectively supplying liquid under pressure to said hydraulic actuator for opening and closing said slave valve, and a moisture responsive sensor formed for operating said pilot valvE to effect opening of said slave valve when the moisture content of the soil falls below a predetermined amount and to effect closing of the slave valve when the moisture content of the soil exceeds a predetermined amount, said pilot valve comprising: a housing providing a chamber adapted for connection to a source of liquid under pressure, a valve seat across an end of said chamber, a ball valve member movable in said chamber toward and away from said valve seat, a tubular stem slidably mounted in said housing for axial movement to displace said ball from said seat, spring means urging said ball against said seat, said housing having a first passage downstream of said valve seat and adapted for connection to a hydraulic device for transmitting liquid under pressure thereto when said ball is displaced from said seat, said housing having a second passage adapted for venting liquid therefrom, said tubular stem being formed for blocking off said second passage when said stem is displacing said ball from said valve seat and having an opening therethrough for communicating said first passage with said second passage when said stem is not displacing said ball from said valve seat.

Claim 68

In an irrigation system having a supply conduit for water under pressure, a slave valve mounted in said conduit for controlling the flow of water therethrough, a hydraulic actuator for said slave valve, a pilot valve formed for selectively supplying liquid under pressure to said hydraulic actuator for opening and closing said slave valve, and a moisture responsive sensor formed for operating said pilot valvE to effect opening of said slave valve when the moisture content of the soil falls below a predetermined amount and to effect closing of the slave valve when the moisture content of the soil exceeds a predetermined amount, said pilot valve comprising: a housing providing a chamber adapted for connection to a source of liquid under pressure, a valve seat across an end of said chamber, a ball valve member movable in said chamber toward and away from said valve seat, a tubular stem slidably mounted in said housing for axial movement to displace said ball from said seat, spring means urging said ball against said seat, said housing having a first passage downstream of said valve seat and adapted for connection to a hydraulic device for transmitting liquid under pressure thereto when said ball is displaced from said seat, said housing having a second passage adapted for venting liquid therefrom, said tubular stem being formed for blocking off said second passage when said stem is displacing said ball from said valve seat and having an opening therethrough for communicating said first passage with said second passage when said stem is not displacing said ball from said valve seat.

Claim 69

A pilot and slave valve construction, comprising: a pilot valve housing providing a chamber adapted for connection to a source of liquid under pressure, a valve seat across an end of said chamber, a ball valve member movable in said chamber toward and away from said valve seat, a tubular stem slidably mounted in said housing for axial movement to displace said ball from said seat, spring means urging said ball against said seat, said pilot valve housing having a first passage downstream of said valve seat and adapted for connection to a slave valve for transmitting liquid under pressure thereto when said ball is displaced from said seat, said pilot valve housing having a second passage adapted for venting liquid therefrom, said tubular stem being formed for blocking off said second passage when said stem is displacing said ball from said valve seat and having an opening therethrough for communicating said first passage with said second passage when not displacing said ball from said valve seat, a slave valve housing, a slave valve seat in said slave valve housing, a slave valve member movable toward and away from said slave valve seat, a slave valve stem axially reciprocable in said slave valve housing and secured to said slave valve member for joint movement therewith, a cylindrical chamber in said slave valve housing co-axially containing a portion of said slave valve stem, a piston on said slave valve stem in said cylindrical chamber, said slave valve member and said slave valve stem and said piston having a passage therethrough for communicating the end of said cylindrical chamber remote from said slave valve member with liquid under pressure passing through said slave valve seat, said slave valve stem and said piston being formed with a passage therethrough for communicating the end of said cylindrical chamber adjacent to said slave valve member with the end of said slave valve stem remote from said slave valve member, spring means in said cylindrical chamber urging said slave valve member away from said slave valve seat, a first conduit communicating said first passage in said pilot valve housing with said end of said slave valve stem remote from said slave valve member, and a second conduit communicating said chamber in said pilot valve housing with said first named end of said cylindrical chamber in said slave valve housing.

Claim 70

A pilot and slave valve construction, comprising: a pilot valve housing providing a chamber adapted for connection to a source of liquid under pressure, a valve seat across an end of said chamber, a ball valve member movable in said chamber toward and away from said valve seat, a tubular stem slidably mounted in said housing for axial movement to displace said ball from said seat, spring means urging said ball against said seat, said pilot valve housing having a first passage downstream of said valve seat and adapted for connection to a slave valve for transmitting liquid under pressure thereto when said ball is displaced from said seat, said pilot valve housing having a second passage adapted for venting liquid therefrom, said tubular stem being formed for blocking off said second passage when said stem is displacing said ball from said valve seat and having an opening therethrough for communicating said first passage with said second passage when not displacing said ball from said valve seat, a slave valve housing, a slave valve seat in said slave valve housing, a slave valve member movable toward and away from said slave valve seat, a slave valve stem axially reciprocable in said slave valve housing and secured to said slave valve member for joint movement therewith, a cylindrical chamber in said slave valve housing co-axially containing a portion of said slave valve stem, a piston on said slave valve stem in said cylindrical chamber, said slave valve member and said slave valve stem and said piston having a passage therethrough for communicating the end of said cylindrical chamber remote from said slave valve member with liquid under pressure passing through said slave valve seat, said slave valve stem and said piston being formed with a passage therethrough for communicating the end of said cylindrical chamber adjacent to said slave valve member with the end of said slave valve stem remote from said slave valve member, spring means in said cylindrical chamber urging said slave valve member away from said slave valve seat, a first conduit communicating said first passage in said pilot valve housing with said end of said slave valve stem remote from said slave valve member, and a second conduit communicating said chamber in said pilot valve housing with said first named end of said cylindrical chamber in said slave valve housing.