Patent Description:
The invention relates to drain check valves and pressure regulators for supplying water to irrigation sprinklers and nozzles.

Irrigation systems often have many sprinklers and nozzles arranged along an extended water supply pipe. A water supply pipe in a center pivot irrigation system may extend a quarter to half a mile (<NUM> to <NUM> meters). The water supply pipe may have a diameter of six to ten inches (<NUM> to <NUM> millimeters) and provide water for over a hundred sprinklers or nozzles arranged along the pipe. Similarly, solid set irrigation systems may include long rows of water supply pipes placed on the ground between rows of crops with sprinklers on posts at regular locations along the supply pipes. Each sprinkler or nozzle is typically connected to the water supply pipe by a smaller water pipe that extends substantially vertically, i.e., within <NUM>-<NUM> degrees of vertical. A drain check valve and/or a pressure regulator may be connected to the smaller water pipe upstream of the sprinkler or nozzle.

As a water supply pipe extends hundreds of meters, the pipe may rise over hills and drop into low points of an agricultural field. When water flow to a water supply pipe is turned off, water collects at low points in the pipe and drains out through sprinklers or nozzles at the low points. Water draining from sprinklers and nozzles after shutting off the water supply is not desired in certain irrigation applications, such as for crops that do not tolerate temporary flooding. The concern of excessive water on crops as water drains through sprinklers becomes greater for irrigation schedules that apply periodic bursts of water to the crops with water turned off between bursts.

To address concerns of water draining through sprinklers and nozzles, each sprinkler or nozzle may be connected to a drain check valve configured to turn on or off the flow of water to the sprinkler or nozzle. The drain check valve may automatically close in response to water pressure dropping below a threshold level and automatically open in response to the pressure increasing above the threshold.

Drain check valves may be integrated with pressure regulators. Pressure regulators provide water at a uniform pressure to sprinklers and nozzles. Pressure regulators compensate for pressure variations in the water flowing through a water supply pipe towards the sprinklers and nozzles. The pressure variations may be caused by height variations in the water supply pipe and frictional losses along the long lengths of the pipes.

Sprinklers and nozzles are typically designed to receive water under a relatively low pressure and within a narrow pressure range. Pressure regulators are often connected immediately upstream of a sprinkler or nozzle to ensure that the water pressure at the inlet to the sprinkler or nozzle is within a design pressure range for the sprinkler or nozzle.

<CIT> discloses a known pressure regulator comprising the features of a flow control device according to the preamble of claims <NUM> and <NUM>.

The inventors conceived and disclosed herein a drain check valve that may be integrated with a pressure regulator. The drain check valve includes an elongated drain check shuttle assembly within a housing. The drain check shuttle assembly moves axially within the housing between a forward, upstream position at which the assembly shuts off water flow through the drain check valve and a rear, downstream position which opens water flow through the drain check valve.

The drain check shuttle assembly includes annular seals, such as O-rings, that prevent water leakage past the assembly into an internal chamber of the housing while the assembly is both in the forward and rear positions, and while the assembly moves between these positions. While the drain check shuttle assembly is in the forward position, another seal engages a strut of a valve seat to prevent leakage through a water flow passage in the drain check valve. This seal disengages the strut as the drain check shuttle assembly moves towards the rear position. The drain check shuttle assembly is elongated to enhance its ability to move between the forward and rear positions while maintaining watertight seals and aligning with the strut and valve seat as the assembly moves to the forward position.

The invention may be embodied as a flow control device comprising: a housing having a flow passage including an inlet flow passage and an outlet flow passage; a hollow tube in the housing and defining a tube passage included in the flow passage, a valve seat in the flow passage and facing an inlet to the hollow tube; a cylindrical liner fixed to the housing, separated from the flow passage; and including at least one slot; and a drain check shuttle assembly in the housing and configured to move relative to the housing and the hollow tube, wherein the drain check shuttle assembly includes: a first position at which the drain check shuttle assembly closes a gap between the valve seat and the inlet to the hollow tube; and a second position in which the drain check shuttle assembly is displaced from the valve seat to open the gap, and the drain check shuttle assembly includes a cylindrical carrier extending into the cylindrical liner and in sliding contact with the cylindrical liner, wherein the cylindrical liner includes an opening through which extends the hollow tube.

The cylindrical liner may include at least one slot and the cylindrical carrier may include at least one catch protruding into the at least one slot of the cylindrical liner, wherein axial and rotational movement of the drain check shuttle assembly is restricted by the at least one catch engaging the at least one slot. The at least one slot may be oriented parallel to a longitudinal axis of the hollow tube. The at least one slot may be in a rear region of the cylindrical carrier. The at least one slot is at least three slots arranged symmetrically around the cylindrical liner.

The flow control device may include a helical spring having a spring end seated against an internal annular surface of the cylindrical carrier to bias the drain check shuttle assembly towards the first position.

The hollow tube may be a plunger configured to move axially with respect to the housing, and the flow control device further comprises an annular diaphragm forming a deformable seal between a liquid-filled chamber receiving liquid flowing through the outlet flow passage and an internal chamber within the housing.

The drain check shuttle assembly may include: an outer annular seal mounted to an outer surface of the cylindrical carrier and configured to form a seal between the drain check shuttle assembly and the housing, a first inner annular seal mounted to the cylindrical carrier and extending around an opening in the cylindrical carrier, wherein the first inner annular seal is configured to form a seal between the drain check shuttle assembly and a strut supporting the valve seat and attached to the housing, and a second inner annular seal mounted to the cylindrical carrier and extending around the opening, wherein the second inner annular seal is configured to form a seal between the drain check shuttle assembly and the hollow tube.

The first annular seal support may be mounted to a front end of the carrier, wherein the first annular seal support includes an outer lip abutting the outer annular seal and an inner lip abutting the first inner annular seal. The second annular seal support may be seated on an inside surface of the carrier and extending around the opening, wherein the second annular seal support includes a forwardly angled lip gripping the first inner annular seal and the first annular seal support includes a rearwardly angled lip gripping the first inner annular seal.

The invention may be embodied as a flow control device comprising: a housing including an inlet flow passage and an outlet flow passage; a hollow tube within the housing defining a tube passage wherein a flow passage through the housing includes the tube passage, the inlet flow passage and the outlet flow passage; a valve seat attached to the housing, extending into the inlet flow passage and facing an inlet to the hollow tube, and a drain check shuttle assembly within the housing and configured to move relative to the housing and the hollow tube, wherein the drain check shuttle assembly has: a forward position at which the drain check shuttle assembly closes a gap between the valve seat and the inlet to the hollow tube; and a rearward position at which the drain check shuttle assembly does not close the gap, and the drain check shuttle assembly comprises a carrier including a forward region and a rear region, wherein: the forward region of the drain check shuttle assembly includes an outer seal configured to seal the drain check shuttle assembly with respect to the housing, an opening to receive the hollow tube, a first inner seal configured to seal the drain check shuttle assembly with respect to the valve seat while the drain check shuttle assembly is in the forward position, and a second inner seal configured to seal the drain check shuttle assembly with respect to the hollow tube, and the rear region has an axial length of at least one half of the axial length of the drain check shuttle assembly, and the rear region extends rearward of the forward region and the opening.

The flow control device may include a liner in the housing and enclosing the rear region of the carrier, wherein an inner surface of the liner forms a bearing surface against which slides an outer surface of the rear region. The liner may include at least one slot, and the at least one slot receives at least one catch of the carrier, wherein the at least one slot engages the catch to limit axial and angular movement of the drain check shuttle assembly. The at least one slot may be in a rear region of the carrier and the at least one catch may be at a rear end of the rear region of the carrier. The at least one slot may be at least three slots arranged symmetrically around the carrier.

The hollow tube, the drain check shuttle assembly and the liner may be coaxial.

The flow control device may include a helical spring including a first end seated against an internal surface of the carrier.

In the flow control device, the hollow tube may be a plunger configured to move axially with respect to the housing, and the flow control device further comprises a diaphragm forming a deformable seal between a water chamber in fluid communication with a liquid flowing through an outlet to the housing and an internal chamber within the housing.

The flow control device may include a plunger support, wherein an inner annular rim of a diaphragm is clamped between the plunger support and a flange of the hollow tube, and the plunger support includes a frustoconical support receiving and supporting the hollow tube. The plunger support may include a forward-facing side comprising an annular channel receiving an end of the helical spring, and a rearward-facing side including an annular recess configured to receive the inner annular rim of the diaphragm.

The drain check shuttle assembly may include a first inner annular seal mounted to the forward region of the carrier and extending around the opening in the carrier, wherein the first inner annular seal is configured to form a seal between the drain check shuttle assembly and a strut of the valve seat, and a second inner annular seal mounted to the carrier and extending around the opening in the carrier, wherein the second inner annular seal is configured to form a seal between the drain check valve and an outer surface of the hollow tube.

Other aspects, features, and advantages of the disclosed and novel drain check valve for a pressure regulator are apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of this technology.

<FIG> shows a flow-through type pressure regulator <NUM> having a drain check valve. The pressure regulator <NUM> includes a housing <NUM> formed by an inlet cap <NUM> and an outlet cap <NUM>. The inlet and outlet caps may be connected by a snap or screw connection, a threaded collar (not shown), by welding or other fastening means. The inlet cap <NUM> includes an annular ridge or teeth <NUM> (<FIG>) extending radially outward at an end of the inlet cap. The outlet cap <NUM> includes an annular lip <NUM> (<FIG>) extending radially inwardly and at an end of the outlet cap. The ridge or teeth <NUM> of the inlet cap engage the lip of the outlet cap <NUM> to lock the inlet and outlet caps together.

<FIG> are cross-sectional views of the pressure regulator <NUM>. The inlet cap <NUM> includes an inlet flow passage <NUM>, and the outlet cap <NUM> includes an outlet flow passage <NUM>. The inlet and outlet flow passages may have threaded surfaces to receive water pipes (not shown) connected to opposite ends of the pressure regulator. A vertical water pipe (not shown) connects to the inlet of the pressure regulator to the water supply pipe. The outlet flow passage <NUM> may be connected directly or via a pipe section to a sprinkler or nozzle (not shown) that hangs or is otherwise supported by the pressure regulator. The inlet and outlet flow passages <NUM>, <NUM> may be coaxial as shown in <FIG>, or may have offsetting parallel axes. Alternatively, the axes of the inlet and outlet passages <NUM> and <NUM> may intersect to form an acute angle, such as an angle of less than <NUM>-<NUM> degrees.

The flow passage through the pressure regulator <NUM> extends through the inlet flow passage <NUM>, over and around a strut <NUM> supporting a valve seat <NUM>, through a plunger flow passage <NUM> of a plunger <NUM>, and through the outlet flow passage <NUM>. The strut <NUM> extends from an inner wall <NUM> of the inlet cap into the flow passage. The rear end of the strut forms a valve seat <NUM>. The upstream surface(s) of the strut may be smooth and sloped in a downstream direction to reduce disruption of water flow through the inlet flow passage <NUM>.

The flow passage includes a gap <NUM> (<FIG>) between the valve seat <NUM> and the inlet <NUM> to the plunger. The plunger <NUM> may move axially in the housing <NUM> to regulate pressure in a manner described below. If the device <NUM> is not configured as a pressure regulator, the plunger <NUM> may be a hollow tube fixed to the outlet cap <NUM> such that the plunger does not move axially.

Water flows through the pressure regulator while the gap <NUM> is open, as is shown in <FIG>. As shown in <FIG>, water is prevented from flowing through the pressure regulator by a drain check shuttle assembly <NUM>. The drain check shuttle assembly slides between a forward position as shown in <FIG>, to close the gap and a rearward position as shown in <FIG> that opens the gap <NUM>.

The drain check shuttle assembly <NUM> may act as an on-off valve that either entirely opens the gap <NUM> or entirely closes the gap. The drain check shuttle assembly <NUM> may have steady state positions only in its forward and rearward positions.

The gap <NUM> is the narrowest region of the flow passage through the pressure regulator. The gap restricts water flow through the drain check or pressure regulator. If the drain check does not include a pressure regulator, the gap may be constant.

If a pressure regulator is integrated with the drain check, the gap <NUM> varies to regulate water flow through the pressure regulator. The water pressure in the outlet flow passage <NUM> depends on the degree to which the gap restricts water flow. The wider the gap, the less the restriction and the lower the relative drop across the gap. The narrower the gap, the greater the restriction and the greater the reduction in water pressure across the gap.

Pressure regulation is achieved by varying the width of the gap <NUM>, while the drain check shuttle assembly is in the rearward position. The width of the gap is the distance from the valve seat <NUM> to the inlet <NUM> of the plunger. The plunger <NUM> moves axially to widen and narrow the gap, and thereby adjusts the water pressure in the outlet flow passage <NUM>. <FIG> shows the inlet <NUM> of the plunger in a rearward position which opens the gap to a widest position. <FIG> shows the inlet <NUM> of the plunger in a forward position seated on the valve seat <NUM> which closes the gap. In <FIG> and <FIG>, the drain check shuttle assembly <NUM> is in the rearward position and thus does not close the gap <NUM>.

The inlet <NUM> of the plunger is positioned between the rearward and forward positions to adjust the width of the gap <NUM> and thereby controls the pressure in the outlet flow passage <NUM>. The plunger <NUM> may move automatically to achieve a uniform pressure at the outlet of the pressure regulator. The plunger <NUM> may move in response to changes in the water pressure in the outlet flow passage. The movement of the plunger to adjust the gap <NUM> suppresses these changes and achieves a generally uniform water pressure at the outlet flow passage <NUM>.

As shown in <FIG>, the drain check shuttle assembly <NUM> includes an opening <NUM> in an upper region of the assembly. The plunger <NUM> extends through the opening <NUM>. The plunger moves axially relative to the drain check shuttle assembly <NUM> and the outlet cap <NUM> as the plunger moves to regulate water pressure. Similarly, the drain check shuttle assembly <NUM> moves axially relative to the plunger and the housing as the assembly <NUM> moves between its forward and rearward positions.

The drain check shuttle assembly <NUM> includes an outer annular seal <NUM>, such as an O-ring, that forms a watertight seal between the assembly <NUM> and an inner wall <NUM> of the housing <NUM> to prevent leakage of water into an internal chamber <NUM> within the drain check or pressure regulator. The drain check shuttle assembly <NUM> also forms a watertight seal, via a second inner annular seal <NUM>, such as an O-ring, with the plunger <NUM> to prevent leakage of water into the chamber <NUM>. These watertight annular seals <NUM>, <NUM> are maintained while the drain check shuttle assembly moves between its forward and rearward positions, and while the plunger moves axially.

While in the forward position, the drain check shuttle assembly <NUM> forms a watertight seal, via a first inner annular seal <NUM>, such as an O-ring, with the strut <NUM> to prevent water leakage through the gap <NUM>. The watertight seal with the valve seat is released when the drain check shuttle assembly <NUM> moves to the rearward position. The seal between the drain check shuttle assembly and the strut is formed by the first inner annular seal <NUM> that is repeatedly formed and released as the drain check shuttle assembly moves to close and open water flow through the pressure regulator.

As shown in <FIG>, the drain check shuttle assembly <NUM> includes a cylindrical carrier <NUM> that supports the annular seals <NUM>, <NUM>, <NUM>. These annular seals are mounted to a forward region <NUM> of the carrier <NUM>. The annular seals <NUM> and <NUM> are held in place on the forward region by a first annular seal support <NUM>, a second annular seal support <NUM>. The second inner annular seal <NUM> is held in place between the second annular seal support <NUM> and a third annular seal support <NUM>. The annular seals may be formed of elastic materials, such as rubber, plastics, polybutadiene, or polyurethane.

The outer annular seal <NUM> slides across the inner wall <NUM> of the inlet cap as the drain check shuttle assembly <NUM> moves between the forward and rearward positions. The outer annular seal <NUM> seats on an annular ledge <NUM> in an outer surface of the carrier <NUM>. The outer annular seal <NUM> is sandwiched between the ledge <NUM> and an outer lip <NUM> of the first annular seal support <NUM>. The outer annular seal <NUM> is held in place by the ledge <NUM>, an annular wall of the carrier adjacent the ledge <NUM>, the outer lip <NUM> of the first annular seal support <NUM> and the inner wall <NUM> of the housing.

The first inner annular seal <NUM> is held between an annular inner lip <NUM> on the first annular seal support <NUM>, and an annular upper lip <NUM> of the second annular seal support <NUM>. The inner lip <NUM> and the upper lip <NUM> both extend radially inward a distance greater than a radius of a cross section of the first inner annular seal <NUM> but less than the diameter of the first inner annular seal. The lips <NUM>, <NUM> also extend towards each other, e.g., converge in a radially inward direction, to grasp the first inner annular seal <NUM>. The first inner annular seal <NUM> is held secure by the lips <NUM>, <NUM> and against a first inner cylindrical surface <NUM> of the carrier <NUM>. The inner circumferential surface of the first inner annular seal <NUM> is unsupported by the valve seat or strut while the drain check shuttle assembly <NUM> is in the rearward position. While the inner circumferential surface of the first inner annular seal <NUM> is unsupported, the converging lips <NUM>, <NUM> securely hold the first inner annular seal <NUM> within the drain check shuttle assembly. By securely holding the first inner annular seal <NUM>, the converging lips <NUM>, <NUM> ensure that the first inner annular seal <NUM> is not dislodged from the carrier as the first inner annular seal <NUM> moves in and out of contact with the valve seat.

The second inner annular seal <NUM> forms a seal between the drain check shuttle assembly <NUM> and an outer surface of the plunger <NUM>. The second inner annular seal <NUM> remains in contact with the plunger <NUM> as the plunger and drain check shuttle assembly move relative to each other. The second inner annular seal <NUM> may have a circumference and cross-sectional area smaller than that of the first inner annular seal <NUM>. The first inner annular seal <NUM> has a larger circumference because it fits around and seals with the valve seat and particularly around the end of the strut <NUM> which forms the valve seat. The second inner annular seal has a smaller circumference because it fits around and seals with the plunger which may have an outer diameter narrower than the diameter of the valve seat.

The second inner annular seal <NUM> is positioned in the drain check shuttle assembly such that the annular seal always remains in sliding contact with the plunger while the drain check shuttle assembly <NUM> moves relative to the plunger. The second inner annular seal <NUM> supports the plunger near the inlet <NUM> to the plunger while allowing the plunger to move axially with respect to the second inner annular seal <NUM>. The support provided by the second inner annular seal assists in aligning the inlet <NUM> of the plunger with the valve seat <NUM>. The second inner annular seal <NUM> also suppresses movement of the inlet end of the plunger in a radial direction with respect to the axis of the plunger.

To ensure that the second inner annular seal <NUM> is always in contact with the plunger, the axial distance between the first inner annular seal <NUM> and the second inner annular seal <NUM> should be substantially greater than the gap <NUM> between the valve seat and the inlet to the plunger, while the plunger is in the rearward position. The distance between the first and second inner annular seals may be in a range of <NUM>- <NUM> percent of the gap <NUM> while the plunger is in the rearward position.

The axial distance between the first and second annular seals <NUM>, <NUM>, may be set by the axial lengths of the second annular seal support <NUM> and the third annular seal support <NUM>. The second annular seal support <NUM> and third annular seal support <NUM> are mounted in the carrier <NUM> such that they are coaxial with the carrier and adjacent to each other in the carrier. The second annular seal support <NUM> and third annular seal support <NUM> may be combined into a single, one-piece component.

The second inner annular seal <NUM> is supported in the carrier <NUM> by being sandwiched between an inner annular ledge <NUM> of the carrier and the third annular seal support <NUM>. The third annular seal support <NUM> is seated in the carrier <NUM> and has an outer surface adjacent a second inner cylindrical surface <NUM> on the carrier. The second inner cylindrical surface <NUM> has a smaller diameter than the first inner surface <NUM> of the carrier <NUM>.

The inside cylindrical surface of the third annular seal support <NUM> and a first inside cylindrical surface <NUM> of the second annular seal support <NUM> may have the same diameter. These diameters are slightly greater, such as by <NUM>-<NUM> percent, than the inside diameter of the second inner annular seal <NUM>, to avoid abutting the outer surface of the plunger. The second annular seal support <NUM> includes a second inside cylindrical surface <NUM> that has a larger diameter than the first inside cylindrical surface <NUM>, such as in a range of <NUM>-<NUM> percent larger. The larger diameter of the second inside cylindrical surface <NUM> is to accommodate the larger inner diameter of the first inner annular seal <NUM>. The larger diameter of the second inside cylindrical surface <NUM> avoids having the second annular seal support <NUM> abut the outer surface of the strut <NUM> while the drain check shuttle assembly is in a forward position. Triangular ribs <NUM> on the second annular seal support <NUM> may be arranged symmetrically around the second inside cylindrical surface <NUM> and adjacent the interface with the first inside cylindrical surface <NUM>. The triangular ribs <NUM> serve as ramped stops for the valve seat and to prevent the valve seat from hitting the ledge between the first and second inside cylindrical surfaces <NUM>, <NUM>.

A rear O-ring <NUM> (<FIG>) assists in dampening outlet pressure feedback from outlet flow passage <NUM> into the water chamber <NUM>. The rear O-ring does not form a watertight seal with the plunger.

Water in the outlet flow passage <NUM> flows over the O-ring <NUM> and into a water chamber <NUM> (<FIG>) in the outlet cap <NUM>. The water chamber <NUM> is adjacent the diaphragm <NUM>, as shown in <FIG>. Also, the rear portion of the plunger may fit loosely in the outer flow passage <NUM> as the plunger and outer flow passage need not be coaxial, and the plunger moves reciprocally in the outlet cap <NUM> in a pressure regulator configuration.

The annular front surface <NUM> of the drain check shuttle assembly <NUM> faces the water flowing from the inlet flow passage <NUM> and into the inlet <NUM> of the plunger <NUM>. The front surface <NUM> moves relative to the inlet <NUM> of the plunger due to the movements of the plunger and the drain check shuttle assembly. The front surface <NUM> is annular and may be curved in radial directions with respect to the axis of the plunger. The front surface <NUM> may have shallow grooves oriented radially. The curved surface and grooves direct water flowing over the front surface <NUM> towards the inlet to the plunger.

The front surface <NUM> is not always aligned with the inlet <NUM> of the plunger <NUM> due to the relative movements of the drain check shuttle assembly <NUM> and the plunger. The front surface is forward of the inlet to the plunger while the drain check shuttle assembly is in the forward position. The front surface is rearward of the inlet to the plunger while the drain check shuttle assembly is in the rearward position. The front surface <NUM> may be aligned with the inlet <NUM> to the plunger only while the plunger and the drain check shuttle assembly are in their rearward positions.

The carrier <NUM> includes a rear region <NUM> that may be an extended cylindrical section that extends from the annular ledge <NUM> of the carrier rearward to an annular end <NUM> of the carrier. The rear region <NUM> of the carrier that extends the drain check shuttle assembly <NUM> rearward to assist in keeping the opening <NUM> aligned with the strut <NUM> as the assembly moves forward towards the valve seat. The rear region <NUM> also aids in providing smooth sliding of the drain check shuttle assembly in the housing <NUM> and prevents the assembly from becoming stuck as it moves forward and rearward. The rear region <NUM> may be one-half to three-quarters or more of the entire axial length of the drain check shuttle assembly <NUM>.

An outer surface of a forward portion of the rear region <NUM> is in sliding engagement with an inner wall <NUM> of the inlet cap <NUM>. The sliding engagement between the outer surface of the rear region <NUM><NUM> and the inner wall <NUM> serves to keep the drain check shuttle assembly aligned with the valve seat as the drain check shuttle assembly slides between its forward and rearward positions and aids in preventing the assembly <NUM> from becoming angularly offset from the inner wall <NUM>.

The rear end of the rear region <NUM> of the carrier extends into a cylindrical liner <NUM>. The liner <NUM> is seated in the housing such that the liner does not move relative to the housing. The liner <NUM> has an inner cylindrical surface that receives and forms a bearing surface with respect to the outer surface of the rear region <NUM> of the carrier <NUM>. The sliding engagement between the liner and the rear region <NUM> aids in keeping the drain check shuttle assembly <NUM> aligned with the liner and the valve seat.

As shown in <FIG>, the liner <NUM> includes closed slots <NUM> and open slots <NUM> both oriented parallel to the axis of the plunger. The closed slots <NUM> are closed at a forward end <NUM> and a rear end <NUM>. The closed slots <NUM> receive a catch <NUM> (<FIG>) extending radially outward from the end <NUM> of the rear region <NUM> of the carrier <NUM>. The forward end <NUM> of the closed slots <NUM> engage a catch <NUM> to prevent further forward axial movement of the carrier <NUM> and its drain check shuttle assembly <NUM>. The rear end <NUM> of the closed slots <NUM> engage the catch <NUM> to prevent further rearward axial movement of the carrier and the drain check shuttle assembly. The closed slots <NUM> prevent the drain check shuttle assembly <NUM> from moving too far forward or rearward, and thereby becoming stuck in the housing. The closed slots <NUM> also substantially suppress rotational movement of the drain check shuttle assembly within the liner. Suppressing rotational movement reduces the risk that the annular seals <NUM>, <NUM>, <NUM> are subjected to angular forces that could cause the annular seals to break their watertight seals or become damaged.

The open slots <NUM> in the liner <NUM> include a reinforced rear end <NUM> that stops rearward movement of the drain check shuttle assembly <NUM> by engaging the end <NUM> of the carrier and/or the catch(es) <NUM>. The reinforcement may be a flange at the end of the slot. The reinforced rear end <NUM> may be positioned such that the end <NUM> of the carrier <NUM> engages before the catch(es) <NUM> engage(s) the rear ends <NUM> of the closed slots <NUM>.

Slots <NUM> in the rear end <NUM> of the carrier allow the catches <NUM> to bend inward as the carrier is inserted into the liner <NUM> during assembly of the pressure regulator or drain check. During operation of the pressure regulator or drain check, the catches <NUM> are not intended to escape from the closed slots <NUM> in the liner <NUM>.

As shown in <FIG> and <FIG>, the lower annular edge <NUM> of the liner is seated in the inlet cap to secure an outer rim of an annular diaphragm <NUM> between the edge <NUM> and an annular ledge <NUM> (<FIG>) of the outlet cap. The lower annular edge <NUM> may be relatively thick in a radial direction and supported by ribs <NUM> on the outer surface of the liner. The ribs <NUM> may assist in centering the liner within the housing and thereby aligning the edge <NUM> with the outer rim of the diaphragm.

As shown in <FIG> and <FIG>, the diaphragm <NUM> is an annular disc and has an inner ledge attached to an annular plunger support <NUM>. The plunger support <NUM> is in the liner <NUM> and is supported by the diaphragm <NUM>. The plunger support <NUM> moves with the plunger, and as the diaphragm rolls, due to water pressure changes in the outlet flow passage <NUM> and water chamber <NUM>.

<FIG> and <FIG> show the plunger support <NUM> as having a frustoconical support <NUM> for the plunger. The frustoconical support includes fingers <NUM> that grasp the outer surface of the plunger <NUM>. The fingers <NUM> engage a ridge or recess <NUM> (<FIG>) on the outer surface of the plunger to lock the plunger support <NUM> to the plunger. The locking action also clamps the inner rim of the diaphragm between the annular recess <NUM> of the plunger support and an annular flange <NUM> extending radially outward from and fixed to the plunger.

The plunger support <NUM> has a forward-facing side with an annular channel <NUM> configured to receive an end of a helical spring <NUM>. The rearward-facing end of the plunger support <NUM> includes an annular recess <NUM> to receive the inner rim of the diaphragm <NUM>. The inner rim of the diaphragm <NUM> is clamped between the annular recess <NUM> of the plunger support <NUM> and an outer flange <NUM> on the plunger <NUM>.

The diaphragm <NUM> is between a water chamber <NUM> in the outlet cap <NUM> and the internal chamber <NUM>. The water chamber <NUM> is open to the water flowing through the outlet flow passage <NUM>. The internal chamber <NUM> may be at atmospheric air pressure or may be subjected to a controlled hydraulic pressure from an external source of a pressurized fluid. The internal chamber <NUM> is sealed from the water flowing through the pressure regulator <NUM> by annular seals <NUM>, <NUM>, the carrier <NUM>, liner <NUM>, plunger <NUM> and diaphragm <NUM>.

The pressure differences between the water pressure in the water chamber <NUM> and the gas (air) pressure in the internal chamber <NUM> causes the diaphragm <NUM> to deflect, e.g., roll. The deflection of the diaphragm moves the plunger axially. A rise in the water pressure in the outlet flow passage <NUM> causes the diaphragm to deflect forward and thereby moves the plunger inlet <NUM> towards the valve seat <NUM> to reduce the gap <NUM> which restricts water flow and reduces pressure in the outlet flow passage. A decrease in the water pressure in the water chamber <NUM> deflects the diaphragm rearward and thereby moves the plunger away from the valve seat and opens the gap <NUM> and increases pressure in the outlet flow passage.

The drain check shuttle assembly <NUM> is biased towards its forward position by the helical spring <NUM>. In the forward position, the drain check shuttle assembly closes the gap <NUM> and shuts off water flow through the pressure regulator. The spring force of the helical spring <NUM> and the area of the front surface <NUM> of the first annular seal support <NUM> (which forms the front surface of the drain check shuttle assembly) are selected such that the force applied by water pressure against the front surface <NUM> overcomes the force of the helical spring <NUM> when the water pressure in the inlet exceeds a threshold water pressure. When the water pressure in the inlet flow passage <NUM> exceeds the threshold water pressure, the pressure forces the drain check shuttle assembly <NUM> to move rearward to open the gap <NUM>. As the gap opens, water flows through the pressure regulator or drain check device.

The drain check shuttle assembly <NUM> and helical spring <NUM> may be configured such that the drain check shuttle <NUM> moves quickly between a forward position and a rearward position. The drain check shuttle <NUM> may be configured to not dwell in an intermediate position between the most forward and most rearward positions. Moving the drain check shuttle assembly quickly from the forward position to the rearmost position when the threshold pressure is reached allows the drain check shuttle assembly to function as a simple on-off valve.

A front end of the helical spring <NUM> is seated on an internal annular surface <NUM> of the carrier in the drain check shuttle assembly <NUM>. A rear end of the helical spring is seated on an annular channel <NUM> in the plunger support.

The pressure regulator <NUM> regulates water pressure by maintaining a substantially uniform water pressure at the outlet flow passage <NUM>. Pressure regulation is achieved by adjusting the gap <NUM> between the valve seat <NUM> and the inlet to the plunger. The gap is a constriction to the water flowing through the pressure regulator. Water flowing through the pressure regulator experiences a pressure drop when flowing through the gap. Widening of the gap reduces the pressure drop through the pressure regulator. Narrowing the gap increases the pressure drop through the pressure regulator. The width of the gap is automatically adjusted to maintain a uniform water pressure at the outlet of the pressure regulator.

The width of the gap is adjusted by moving the plunger axially with respect to the housing of the pressure regulator. As the plunger advances forward in the housing, the inlet to the plunger approaches the valve seat and thereby reduces the width of the gap <NUM>. As the plunger moves rearward, the inlet to the plunger moves away from the valve seat and the width of the gap increases.

The helical spring <NUM> biases the plunger <NUM> towards the outlet cap <NUM> and away from the valve seat <NUM>. One end of the helical spring is seated on the drain check shuttle assembly <NUM>. The helical spring <NUM> biases the drain check shuttle assembly forward in the housing of the pressure regulator. The biasing force of the helical spring is overcome when the water pressure in the inlet flow passage <NUM> overcomes the force of the helical spring <NUM> and moves the drain check shuttle assembly to the rearward position.

<FIG> and <FIG> are perspective views of a drain check valve <NUM> having a hollow tube <NUM> fixed with respect to the housing. <FIG> shows a drain check shuttle assembly <NUM> in an open position in which the drain check shuttle assembly is positioned rearward to allow water to flow through the gap <NUM> and into the inlet <NUM> of a flow passage <NUM> through the hollow tube. <FIG> shows the drain check shuttle assembly <NUM> in a forward position which closes the gap <NUM> to block water flow through the drain check valve. <FIG> is a perspective view of the hollow tube <NUM>.

The hollow tube <NUM> is held in a fixed position within the housing by the spring <NUM> that biases an annular flange <NUM> on the hollow tube <NUM> against an annular surface <NUM> of the outlet cap <NUM>. The hollow tube does not move with respect to the housing and, thus, the gap <NUM> does not vary. A diaphragm is not needed between the tube and the housing because the hollow tube does not move relative to the housing.

The hollow tube <NUM> includes a cylindrical wall <NUM> that extends forward from the annular flange <NUM>. The spring <NUM> is in an annular gap <NUM> between an outer surface of a tube portion <NUM> and the inner surface of the wall <NUM>. The tube portion defines the flow passage <NUM>.

An upper annular edge <NUM> of the cylindrical wall <NUM> and an outer surface of the cylindrical wall are adjacent inner surfaces of the cylindrical liner <NUM>. The cylindrical liner <NUM> is a separate component from the hollow tube in the drain check valve <NUM> shown in <FIG> and <FIG>. The cylindrical wall <NUM> provides support for the cylindrical liner <NUM> and assists in positioning the cylindrical liner and the spring in the housing.

A forward cylindrical region <NUM> of the tube portion <NUM> has a narrower outer diameter than does a rearward region <NUM> of the tube portion. The forward cylindrical region <NUM> engages the drain check shuttle assembly <NUM>. The second inner O-ring <NUM> of the drain check shuttle assembly slides against an outer surface of the forward cylindrical region <NUM> as the drain check shuttle assembly moves between the forward (closed) and rear (open) positions. The rearward region <NUM> of the tube portion <NUM> has a greater outer diameter to provide a greater thickness to the tube to increase the structural strength of the tube portion.

<FIG> and <FIG> are perspective views of a drain check valve <NUM> having an integral hollow tube and liner <NUM>. <FIG> shows the drain check shuttle assembly <NUM> in a rearward position that allows water to flow through the open gap <NUM> between the valve seat <NUM> and an inlet <NUM> to a cylindrical tube <NUM> portion of the integral hollow tube and liner, and into a flow passage <NUM> through the cylindrical tube. <FIG> shows the drain check shuttle assembly <NUM> in a forward position that closes the gap <NUM> to prevent water flow into the gap <NUM> and through the drain check valve.

As shown in <FIG>, the integral hollow tube and liner <NUM> is a single-piece component that combines the hollow tube and liner of previously described embodiments. The integral hollow tube and liner <NUM> may be plastic and formed by plastic injection molding, as are many of the other components of the drain check valves and pressure regulators described herein. <FIG> shows the integral hollow tube and liner <NUM> in an assembly with the helical spring <NUM> and the drain check valve assembly <NUM>.

The integral hollow tube and liner <NUM> includes an annular surface <NUM> that receives an end of the helical spring <NUM>. The annular surface <NUM> extends radially outward from the cylindrical tube <NUM> to a liner <NUM> having a generally cylindrical wall <NUM> that is substantially parallel to the cylindrical tube <NUM>. The integral hollow tube and liner <NUM> has features similar to the cylindrical liner <NUM> show in <FIG>. In particular, the integral hollow tube and liner <NUM> includes open slots <NUM> and closed slots <NUM>. The slots receive the catches <NUM>, <NUM> at the end of the cylindrical carrier <NUM> of the drain check shuttle assembly. As shown in <FIG>, the catches <NUM> abut a forward end <NUM> of the closed slots <NUM> in the liner to stop further forward motion of the drain check shuttle assembly <NUM>. Similarly, the open slots <NUM> in the liner have reinforced rear ends <NUM> that abut the catches <NUM> on the cylindrical carrier <NUM> to stop further rearward motion of the drain check assembly.

Claim 1:
A flow control device (<NUM>, <NUM>, <NUM>) comprising:
a housing (<NUM>, <NUM>, <NUM>) having a flow passage including an inlet flow passage (<NUM>) and an outlet flow passage (<NUM>);
a tube (<NUM>, <NUM>, <NUM>) in the housing and defining a tube passage (<NUM>, <NUM>, <NUM>) included in the flow passage;
a valve seat (<NUM>) in the flow passage (<NUM>) and facing an inlet (<NUM>) to the tube;
a liner (<NUM>, <NUM>) within the housing and fixed with respect to the housing, separated from the flow passage, and including at least one slot (<NUM>, <NUM>); and
a drain check shuttle assembly (<NUM>) in the housing and configured to move relative to the housing and the tube, wherein the drain check shuttle assembly has:
a first position at which the drain check shuttle assembly spans a gap (<NUM>) between the valve seat and the inlet to the tube to prevent flow into the tube; and
a second position in which the drain check shuttle assembly is displaced from the valve seat to open the gap and allow flow into the tube; and
the drain check shuttle assembly includes a cylindrical carrier (<NUM>) including an opening (<NUM>) through which extends the tube,
characterized in that
the cylindrical carrier extends into the liner and is in sliding contact with the liner.