AU2013205201B2 - Valve - Google Patents

Abstract

Abstract A valve 1 comprising a body 10, an inlet 12 for fluid to enter the body 10, an outlet 14 for fluid to exit the body 10, a piston member 16 moveable within the body 10, a spring 18 to bias the piston member 16 in a first direction, adjustment means 20 to adjust the maximum flow pressure of fluid that, in use, passes through the valve 1 in an open condition of the valve 1. A fluid flow path is formed through the body 10 of the valve 1 between the inlet 12 and the outlet 14 in an open condition of the valve 1. The inlet 12, the outlet 14and the spring 18 are substantially coaxial. The spring 18 biases the piston member 16 in the first direction to form the fluid flow path in the open condition of the valve 1, such that, in use, fluid is able to flow through the body 10 of the valve 1 between the inlet 12 and the outlet 'S2. 30 1? 16 70 46 uo? 1 4 54 3~~~6 to 2 4(% e6 u 1 5 1.73 --- >

Description

1 2013205201 04 Jan 2017 P/00/011 28/5/91 Regulation 3.2

AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT

Applicant:

Australian Valve Group Pty Ltd

Actual Inventors:

Title of Invention:

Peter John Morris Marcus Eric Ullrot Valve

Address for service:

Golja Haines & Friend PO Box 1014 South Perth Western Australia 6951

The following statement is a full description of this invention, including the best method of performing it known to us: 2 2013205201 04 Jan 2017

Title “Valve”

Technical Field

The present invention relates to a valve. 5 Throughout the specification unless the context requires otherwise, the word “comprise” or variations such as “comprises”, “comprised” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Throughout the specification unless the context requires otherwise, the word 10 “include” or variations such as “includes”, “included” or “including”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

The headings and sub-headings in this specification are provided for convenience to assist the reader, and they are not to be interpreted so as to narrow or limit the 15 scope of the disclosure in the description, claims, abstract or drawings.

Background Art

Any discussion of background art, any reference to a document and any reference to information that is known, which is contained in this specification, is provided only for the purpose of facilitating an understanding of the background 20 art to the present invention, and is not an acknowledgement or admission that any of that material forms part of the common general knowledge in Australia or any other country as at the priority date of the application in relation to which this specification has been filed.

Summary of Invention 25 In accordance with one aspect of the present invention, there is provided a valve comprising 3 2013205201 04 Jan 2017 a body, an inlet for fluid to enter the body, an outlet for fluid to exit the body, a piston member moveable within the body, the piston member being retained by 5 a piston housing, a spring to bias the piston member in a first direction, the inlet, the outlet and the spring are substantially coaxial, a fluid flow path which is formed through the body of the valve between the inlet and the outlet in an open condition of the valve, 10 adjustment means to adjust the maximum flow pressure setting of the valve, the adjustment means comprising a spring tension adjuster and retainer means to retain the spring tension adjuster, such that the spring is located between the piston member and the spring tension adjuster, wherein the body comprises a first body part and a second body part that are 15 detachably connected together, and wherein the piston housing is retained in the body of the valve and the retainer means is connected to the piston housing, and the spring tension adjuster is movable relative to the retainer means to cause compression or expansion of the spring, to increase or decrease tension of the spring, depending upon the 20 direction of movement of the spring tension adjuster to adjust the spring force with which the spring biases the piston member in the first direction and thereby adjust the maximum flow pressure setting of the valve, and wherein the spring tension adjuster is provided with a helical groove and the retainer means is provided with a pin that is received in the helical groove such 25 that the retainer means retains the spring tension adjuster, and wherein the spring biases the piston member in the first direction to an open condition of the valve, such that, in use, fluid is able to flow via the fluid flow path through the body of the valve between the inlet and the outlet and the maximum pressure setting of the valve determines the maximum pressure of fluid that, in 4 2013205201 04 Jan 2017 use, is able to flow through the valve, from the inlet to the outlet, in an open condition of the valve.

Preferably, the valve further comprises a valve seat and the piston member is provided with a valve head that seats on the valve seat in a closed condition of 5 the valve and unseats from the valve seat in an open condition of the valve.

Preferably, the spring, the inlet and the outlet may be substantially coaxial with at least part of the fluid flow path through the body of the valve.

Preferably, the piston housing houses at least a portion of the piston member.

Preferably, adjustment of the maximum flow pressure setting of the valve by the 10 adjustment means results in relative movement between the spring tension adjuster and the piston housing.

Preferably, the relative movement between the spring tension adjuster and the piston housing comprises movement of the spring tension adjuster in a linear direction that is substantially parallel to the coaxial line of the inlet and the outlet. 15 Preferably, the relative movement between the spring tension adjuster and the piston housing comprises rotational movement of the spring tension adjuster.

Preferably, adjustment of the maximum flow pressure setting of the valve by the adjustment means results in relative movement between the spring tension adjuster and the retainer means. 20 Preferably, the relative movement between the spring tension adjuster and the retainer means comprises movement of the spring tension adjuster in a linear direction that is substantially parallel to the coaxial line of the inlet and the outlet.

Preferably, the relative movement between the spring tension adjuster and the retainer means comprises rotational movement of the spring tension adjuster. 25 Preferably, the spring is located between a spring tension adjuster and the piston housing.

Preferably, the valve further comprises visual indication means visible from exterior of the valve to indicate the maximum flow pressure to which the valve is set. 5 2013205201 04 Jan 2017

Preferably, a seal is provided between the valve seat and the internal surface of the body of the valve.

The piston housing and the valve seat may be provided as a single unit.

The piston housing and the adjustment means may be provided as a single unit, 5 for example, in the form of a cartridge.

Preferably, the piston housing and the retainer means are substantially immovable relative to one another.

Preferably, the spring tension adjuster is engagable by a tool to rotate the spring tension adjuster to thereby adjust the maximum flow pressure setting of the valve. 10 Preferably, the retainer means is substantially tubular.

Preferably, the piston housing is prevented form rotating in the body of the valve.

The expression “maximum flow pressure” as used herein refers to the pressure to which the valve is set that determines the maximum pressure at which fluid can flow through the valve and exit from the outlet of the valve in an open condition of 15 the valve. This is also referred to herein as the “maximum pressure setting” or “maximum flow pressure setting” of the valve, having regard to the particular context in which the expressions are used.

Brief Description of Drawings

The present invention will now be described, by way of example only, with 20 reference to the accompanying drawings, in which:

Figure 1A is a first side view of a first embodiment of a valve in accordance with the present invention;

Figure 1B is an end view of the valve shown in Figure 1 A, with the maximum flow pressure of the valve set to its lowest setting; 25 Figure 1C a second side view of the valve shown in Figure 1A;

Figure 1D is an end view of the valve shown in Figure 1C, with the maximum flow pressure of the valve set to its highest setting; 6 2013205201 04 Jan 2017

Figure 1E is a cross sectional side view taken along the line A - A in Figure 1 A, with the maximum flow pressure of the valve set to its lowest setting and the valve in an open condition;

Figure 1F is a cross sectional side view taken along the line B - B in Figure 1C, 5 with the maximum flow pressure of the valve set to its highest setting and the valve in an open condition;

Figure 1G is a cross sectional side view taken along the line A - A in Figure 1 A, with the maximum flow pressure of the valve set to its lowest setting and the valve in a closed condition; 10 Figure 1H is a cross sectional side view taken along the line B - B in Figure 1C, with the maximum flow pressure of the valve set to its highest setting and the valve in a closed condition;

Figure 11 is an exploded view of the valve of the first embodiment shown in Figures 1A to 1H; 15 Figure 1J is an exploded view of the valve shown in Figure 1A showing the piston housing and the adjuster connected to form a cartridge;

Figure 2A is a first perspective view of an embodiment of another valve with adjustable maximum flow pressure, with the maximum flow pressure of the valve set to its lowest setting; 20 Figure 2B is a side view of the valve shown in Figure 2A, with the maximum flow pressure of the valve set to its lowest setting;

Figure 2C a second perspective view of the valve shown in Figure 2A, with the maximum flow pressure of the valve set to its highest setting;

Figure 2D is a side view of the valve shown in Figure 2C, with the maximum flow 25 pressure of the valve set to its highest setting;

Figure 2E is a cross sectional side view taken along the line C - C in Figure 2B, with the maximum flow pressure of the valve set to its lowest setting and the valve in an open condition; 7 2013205201 04 Jan 2017

Figure 2F is a cross sectional side view taken along the line D - D in Figure 2D, with the maximum flow pressure of the valve set to its highest setting and the valve in an open condition;

Figure 2G is a cross sectional side view taken along the line C - C in Figure 2B, 5 with the maximum flow pressure of the valve set to its lowest setting and the valve in a closed condition;

Figure 2H is a cross sectional side view taken along the line D - D in Figure 2D, with the maximum flow pressure of the valve set to its highest setting and the valve in a closed condition; 10 Figure 21 is an exploded view of the valve of the second embodiment shown in Figures 2A to 2H;

Figure 3A is a first perspective view of an embodiment of another valve with adjustable maximum flow pressure, with the maximum flow pressure of the valve set to its lowest setting; 15 Figure 3B is a side view of the valve shown in Figure 3A, with the maximum flow pressure of the valve set to its lowest setting;

Figure 3C a second perspective view of the valve shown in Figure 3A, with the maximum flow pressure of the valve set to its highest setting;

Figure 3D is a side view of the valve shown in Figure 3C, with maximum flow 20 pressure of the valve set to its highest setting;

Figure 3E is a cross sectional side view taken along the line E - E in Figure 3B, with the maximum flow pressure of the valve set to its lowest setting and the valve in an open condition;

Figure 3F is a cross sectional side view taken along the line F - F in Figure 3D, 25 with the maximum flow pressure of the valve set to its highest setting and the valve in an open condition;

Figure 3G is a cross sectional side view taken along the line E - E in Figure 3B, with the maximum flow pressure of the valve set to its lowest setting and the valve in a closed condition; 8 2013205201 04 Jan 2017

Figure 3H is a cross sectional side view taken along the line F - F in Figure 3D, with the maximum flow pressure of the valve set to its highest setting and the valve in a closed condition;

Figure 31 is an exploded view of the valve of the third embodiment shown in 5 Figures 3A to 3H;

Figure 4A is a first perspective view of an embodiment of another valve with adjustable maximum flow pressure, with the maximum flow pressure of the valve set to its lowest setting;

Figure 4B is a side view of the valve shown in Figure 4A, with the maximum flow 10 pressure of the valve set to its lowest setting;

Figure 4C a second perspective view of the valve shown in Figure 2A, with the maximum flow pressure of the valve set to its highest setting;

Figure 4D is a side view of the valve shown in Figure 4C, with maximum flow pressure of the valve set to its highest setting; 15 Figure 4E is a cross sectional side view taken along the line G - G in Figure 4B, with the maximum flow pressure of the valve set to its lowest setting and the valve in an open condition;

Figure 4F is a cross sectional side view taken along the line H - H in Figure 4D, with the maximum flow pressure of the valve set to its highest setting and the 20 valve in an open condition;

Figure 4G is a cross sectional side view taken along the line G - G in Figure 4B, with the maximum flow pressure of the valve set to its lowest setting and the valve in a closed condition;

Figure 4H is a cross sectional side view taken along the line H - H in Figure 4D, 25 with the maximum flow pressure of the valve set to its highest setting and the valve in a closed condition; and

Figure 41 is an exploded view of the valve of the second embodiment shown in Figures 4A to 4H. 9 2013205201 04 Jan 2017

Description of Embodiments

FIRST EMBODIMENT

In Figures 1A to 11 of the drawings, there is shown a first embodiment of a valve 1 in accordance with the present invention. The valve 1 comprises a body 10, an 5 inlet 12 for fluid to enter the body 10, an outlet 14 for fluid to exit the body 10, a piston member 16 moveable within the body 10, a spring 18 to bias the piston member 16 in a first direction and an adjuster 20 to adjust the maximum flow pressure of fluid at the outlet 14.

The spring 18 biases the piston member 16 in the direction D (to an open 10 condition of the valve 1), shown in Figures 1E and 1F, such that a fluid flow path is formed between the inlet 12 and the outlet 14 in an open condition of the valve 1.

The inlet 12 and the outlet 14 are substantially coaxially aligned. They are also linearly aligned. The alignment of the inlet 12 and the outlet 14 is shown in Figure 15 1E by the broken line L that represents the coaxial line of the inlet 12 and the outlet 14.

The spring 18 may be substantially helical, having an axial line extending longitudinally therethrough.

The inlet 12, the outlet 14 and the spring 18 are substantially coaxially aligned, 20 which is also represented by the broken line L.

Body 10

The body 10 comprises a first, or inlet, body part 22, and a second, or outlet, body part 24. The inlet body part 22 and the outlet body part 24 are connected adjacent respective ends. The inlet body part 22 and the outlet body part 24 are provided 25 with suitable connection means so that they can be connected, as will be further described herein. The inlet body part 22 is provided with the inlet 12 and the outlet body part 24 is provided with the outlet 14. A screw thread 26 is provided adjacent one end of the inlet body part 22 and a screw thread 28 is provided adjacent one end of the outlet body part 24. The 30 screw thread 26 may be provided at the outer surface of the inlet body part 22 10 2013205201 04 Jan 2017 and the screw thread 28 may be provided at the inner surface of the outlet body part 24 (as can be seen in Figure 11), or, alternatively, vice versa. The screw thread 26 of the inlet body part 22 engages with the screw thread 28 of the outlet body part 24 to thereby connect together the inlet body part 22 and the outlet 5 body part 24. A seal 30 is provided between the inlet body part 22 and outlet body part 24 adjacent the screw threaded connection between the screw threads 26 and 28 to form a fluid tight seal. The seal 30 may be an O-ring. This fluid tight seal prevents fluid leaking from inside the valve 1, through the screw threaded connection between the inlet body part 22 and the outlet body part 24. The inlet 10 body part 22 is provided with flat surfaces 22a, at its exterior, and the outlet part 24 is provided with flat surfaces 24a at its exterior. The flat surfaces 22a and 24a may be engaged with suitable tools to untighten and retighten the screw threaded connection between the screw threads 26 and 28, if required.

Since the inlet body part 22 and the outlet body part 24 are screw threadedly 15 connected together, they may be disconnected, i.e. detached, from one another by unscrewing the screw threaded connections. The inlet body part 22 and the outlet body part 24 may be reconnected by engaging and retightening their respective screw threads 26 and 28. A thread locking/sealing compound (for example, such as that sold under the trade mark LOCTITE®) may be applied to 20 the screw threads 26 and 28 prior to engaging and re-tightening them.

The other respective ends of the inlet body part 22 and the outlet body part 24 are each provided with suitable connection means to connect the inlet body part 22 and the outlet body part 24 to tubing or pipes such as, for example, pipes in a plumbing installation. In that regard, the inlet body part 22 may be provided with a 25 screw thread 32 at its other end. Similarly, the outlet body part 24 may be provided with a screw thread 34 at its other end. In use, the screw threads 32 and 34 are used to connect the valve 1 to the pipes, such as pipes in a plumbing installation. Whilst both of the screw threads 32 and 34 are shown in Figures 1 A, 1C, and 1E to 11 as being on the exterior (i.e. male screw threads) of the inlet 30 body part 22 and the outlet body part 24, in alternative embodiments (not shown) one or both of these screw threads may be provided on the interior (i.e. a female screw thread) of the inlet body part 22 and the outlet body part 24.

Piston Member 16 11 2013205201 04 Jan 2017

The piston member 16 comprises a piston head (or valve head) 36, a base 38 and a neck 40 extending between the piston head 36 and the base 38. A cavity 42 is provided in the base 38 of the piston member 16. The base 38 has an opening 44. 5 The piston head 36 has a seal 46. The seal 46 is substantially annular. The seal 46 may be an O-ring.

The piston head 36 is of a shape that substantially resembles an oblate spheroid, with the seal 46 provided at the circumference of its mid region, which in the case of an oblate spheroid, may be referred to as the equatorial circumference. 10 The piston member 16 is provided with a shoulder 48. The shoulder 48 is formed at the region between the base 38 and the neck 40. The neck 40 has a curved surface 50. As best seen when the piston member 16 is viewed to see its longitudinal dimension, the curved surface 50 has a gradually decreasing cross-sectional diameter from the respective ends of the neck 40 to the mid region of 15 the neck 40, i.e. from the respective ends of the neck 40 adjacent the shoulder 48 and the piston head 36, toward the mid region of the neck 40.

As best seen in Figure 11, the base 38 of the piston member 16 is provided with circumferential grooves 52. The grooves 52 accommodate respective seals 54. The seals 54 may be O-rings 20 Piston Housing 56 and Valve Seat 58

The piston member 16 is housed, or retained, by a piston housing 56. The piston housing 56 is substantially tubular, or sleeve-like. A valve seat 58 is provided such that the piston head 36, of the piston member 16, is able to seat on the valve seat 58 in the closed condition of the valve 1, and unseat from the valve 25 seat 58 in an open condition of the valve 1.

The piston housing 56 and the valve seat 58 are provided as a combination, or single, unit, in one piece, i.e. a piston housing / valve seat unit 60, or simply a housing unit 60.

The piston housing 56 and the valve seat 58 are spaced apart and are connected 30 by webs 62 that extend therebetween. The web 62 may extend partly along the exterior surface of the piston housing 56, away from the valve seat 58. 12 2013205201 04 Jan 2017

Respective spaces 64 are defined by the piston housing 56, the valve seat 58 and the webs 62.

The valve seat 58 defines an upstream side and a downstream side of the valve 1. The upstream side of the valve seat 58 is the side that faces the inlet 12 and 5 the downstream side is the side that faces the outlet 14.

Two of the webs 62 are positioned close to each other to form a channel 66. These two webs 62 are labelled as webs 62a and 62b in Figure 11.

The valve seat 58 is substantially annular in shape. The valve seat 58 has a seating surface 68 around an opening 70 through the valve seat 58. The seating 10 surface 68 has a chamfered portion 72, adjacent the downstream side of the valve seat 58, and an adjoining portion 74 at the inner mid region of the valve seat 58. The valve seat 58 is provided with a groove 76 in its outer surface. A seal 78 is located in the groove 76. The seal 78 may be an O-ring. The seal 78 seals against the internal surface of the outlet body part 24 to ensure that fluid cannot 15 leak between the wall of the body 10 and the valve seat 58.

The base 38 of the piston member 16 is retained, or housed, in the piston housing 56. The piston housing 56 is provided with an inwardly turned flange 80 at one end. This is the end of the piston housing 56 that is nearest the valve seat 58.

The flange 80 surrounds an opening 82 of the piston housing 56. The piston 20 housing 56 is provided with another opening 84 at the other (opposed) end of the piston housing 56. A space 86 is provided inside the piston housing 56. The shoulder 48 of the piston member 16 is able to abut against the flange 80 to prevent further movement of the piston member 16 in the direction D. Thus, the flange 80 acts as a stop to limit the travel of the piston member 16 in the direction 25 D. The piston head 36 is located outside the piston housing 56.

The cross-sectional diameter of the neck 40 of the piston member 16 is less than the diameter of the opening 70 of the valve seat 58 and the opening 82 of the piston housing 56. This allows the neck 40 to pass freely, in either direction (i.e. in the direction D or the direction opposed to the direction D), through the opening 30 70 and the opening 82 when the piston member 16 moves within the body 10 of the valve 1. 13 2013205201 04 Jan 2017 A pair of diametrically opposed slots 88 are provided adjacent the end of the piston housing 56 at which the opening 84 is provided. In addition, the piston housing 56 is provided with slits 90 extending from the opening 84.

Adjuster 20 5 The adjuster 20 comprises a spring tension adjuster 92 and a retainer 94 for the spring tension adjuster 92.

Spring Tension Adjuster 92

The spring tension adjuster 92 is provided with a helical groove 96 in its outer surface. A groove 98 is provided adjacent a first end 100 of the spring tension 10 adjuster 92. The groove 98 accommodates a pressure indicator 102. The pressure indicator 102 has an arcuate portion 104 and a transversely extending marker 106. The arcuate portion 104 is received and retained in the groove 98.

The second end 108 of the spring tension adjuster 92 is provided with a groove 110. A seal 112 is located in the groove 110. The seal 112 may be an O-ring. The 15 seal 112 seals against the internal surface of the retainer 94 to ensure that fluid cannot leak between the spring tension adjuster 92 and the retainer 94.

The spring tension adjuster 92 is provided with a recess 114 adjacent the first end 100. The recess 114 has engagement surfaces 116 that can be engaged with a tool (not shown) to adjust the maximum pressure setting of the valve 1, as will be 20 further described herein. The spring tension adjuster 92 is provided with a second recess 118 adjacent the second end 108 thereof.

The spring tension adjuster 92 does not have a passage extending between the first and second openings 100 and 104 since the recesses 114 and 118 are separated by a partition wall 120. 25 Retainer 94

The retainer 94 is provided with a groove 122 in its outer surface. A seal 124 is located in the groove 122. The seal 124 may be an O-ring. The seal 124 seals against the internal surface of the piston housing 56 to ensure that fluid cannot leak between the piston housing 56 and the retainer 94. 14 2013205201 04 Jan 2017

The retainer 94 and the piston housing 56 are connected such that they are substantially immovable relative to one another. In that regard, the retainer 94 is provided with a wedge arrangement 126 at its outer surface. The wedge arrangement 126 is received in the slots 88, of the piston housing 56, by a snap-5 fit engagement, to thereby connect the retainer 94 and the piston housing 56. The slits 90 are provided so as to allow the end of the piston housing 56, which is proximate to the opening 84, to expand so as to allow the wedge arrangement 126 to pass into the opening 84 and locate in the slots 88. In this way, the retainer 94 is connected to the piston housing 56. 10 The retainer 94 retains the spring tension adjuster 92. In that regard, the retainer 94 is provided with a pin 127 at its internal surface. The pin 127 is received in the helical groove 96 of the spring tension adjuster 92. This retains the spring tension adjuster 92 yet enables the spring tension adjuster 92 to move relative to the retainer 94, and in particular, inwardly and outwardly of the retainer 94, as will be 15 further described herein. A portion 106a of the marker 106 is received in a slit 128 in the retainer 94. The remaining portion 106b of the marker 106 extends over the end of the spring tension adjuster 92. The end of the spring tension adjuster 92 is provided with markings 130 to indicate the maximum flow pressure to which the valve 1 is set. 20 These markings 130 are best seen in Figures 1B and 1D, where the markings for the pressures of 350, 500 and 600 kPa are shown. Markings 132a, optionally, may also be provided on the exterior of the inlet body part 22 to show the direction in which the spring tension adjuster 92 should be rotated to set the required maximum flow pressure of the valve 1. 25 The retainer 94 is substantially tubular, or sleeve-like. A pin 132 extends through an aperture 133 in the inlet body part 22 adjacent the end at which the screw thread 26 is provided. The pin 132 is received in the channel 66 formed between the two webs 62a and 62b. The pin 132 prevents the piston housing 56 from rotating in the body 1. Since the retainer 94 is connected 30 to the piston housing 56 by the snap fit engagement of the wedge 126 in the slots 88, the retainer 94 is also prevented from rotating in the body 10. Since the pin 127 is received in the helical groove 96, the spring tension adjuster 92 is retained by the retainer 94. However, the spring tension adjuster 92 is able to rotate 15 2013205201 04 Jan 2017 relative to the retainer 94. This rotatability of the spring tension adjuster 92 relative to the retainer 94 enables the maximum pressure setting of the valve 1 to be adjusted, as will be further described herein.

The cavity 42 (of the piston member 16), the recess 118 (of the spring tension 5 adjuster 92) and the space 86 inside the piston housing 56 together form a spring chamber 134. The spring 18 extends from a shoulder 138, in the cavity 42 of the piston member 16, to the rear surface 140 of the recess 118. The seals 54, 112 and 124 prevent water entering the spring chamber 134.

Incorporating the cavity 42 (of the piston member 16) and the recess 118 (of the io spring tension adjuster 92) as part of the spring chamber 134, in which the spring 18 is located, contributes to the valve 1 having a relatively compact structure. A passage 142 is formed between the outer surfaces of the piston housing 56 and the spring tension adjuster 92, and the inner surfaces of the inlet body part 22 and the outlet body part 24. The passage 142 is substantially annular in cross-section, 15 and is substantially in the form of an annular cylinder.

The piston housing 56 and valve seat 58 are retained in the body 10. The ends of the webs 62, nearest the opening 84, abut an annular ledge 144 of the outlet body part 24 and the valve seat 58 abuts a surface 146 (that is tapered) of the outlet body part 24. In this way, the piston housing 56 and the valve seat 58 are 20 tightly retained in the body 10 such that they are in a fixed position.

The piston housing 56 and the adjuster 20 can be connected, or assembled, as herein before described, so as to form a single unit in the form of a cartridge. This is shown in Figure 1J by way of reference numeral 148, which identifies this cartridge. Providing the cartridge 148 in this way permits ready assembly of the 25 valve 1 by arranging the cartridge 148 between the inlet body part 22 and the outlet body part 24 and then connecting the inlet body part 22 and the outlet body part 24 together, using the screw threads 26 and 28, with the valve seat 58 positioned in the outlet body part 24.

USE AND OPERATION OF THE FIRST EMBODIMENT 30 The manner of use and operation of the valve 1 of the first embodiment of the present invention will now be described. 16 2013205201 04 Jan 2017

In use, the valve 1 may be installed in a fluid supply line such as, for example, the supply line to a hot water heater, to limit the pressure of the fluid that flows from the outlet 14 to a maximum pressure to which the valve 1 has been set (i.e. the maximum pressure setting of the valve 1) using the adjuster 20. 5 Adjusting the Maximum Flow Pressure

Prior to installation of the valve 1 shown in the drawings, the maximum flow pressure of the valve 1 may be adjusted using the adjuster 20. The maximum flow pressure setting of the valve 1 may be adjusted by inserting a suitable tool, for example, an Allen key, into the recess 114 of the spring tension adjuster 92 and 10 then turning the spring tension adjuster 92 in the required direction, with reference to the markings 130a, to align the required pressure marking 130 with the portion 106b of the maker 106.

The spring tension adjuster 92 is able to move relative to the retainer 94 and the piston housing 56. Since the pin 127 is received in the helical groove 96 of the 15 spring tension adjuster 92 and due to the helical form of the helical groove 96, this movement of the spring tension adjuster 92 is both a rotational movement and a liner movement relative to the retainer 94 and the piston housing 56. The linear movement is parallel to the direction D, i.e. parallel to the axial line of the valve 1. The relative linear movement between the spring tension adjuster 92 and the 20 piston housing 56 is substantially parallel to the coaxial line of the inlet 12 and the outlet 14, represented by the broken line L. The linear movement of the spring tension adjuster 92 results in the spring tension adjuster 92 being moved either further into, or out of, the retainer 94. Correspondingly, this results in the spring tension adjuster 92 being moved either toward, or way from, the piston housing 25 56. This movement of the spring tension adjuster 92 results in the size of the spring chamber 134 being either decreased or increased, by shortening or lengthening its length. The linear movement of the spring tension adjuster 92 results in the spring 18 being either compressed or expanded, depending upon the direction of rotation of the spring tension adjuster 92. That is to say, the spring 30 tension of the spring 18 is either increased or decreased, depending upon the direction of rotation of the spring tension adjuster 92, since rotation of the spring tension adjuster 92 alters the size of the spring chamber 134. Rotating the spring tension adjuster 92 in the direction such that a higher maximum flow pressure is 17 2013205201 04 Jan 2017 set, results in the spring 18 being further compressed, i.e. the spring tension of the spring 18 is increased. On the other hand, rotating the spring tension adjuster 92 in the direction such that a lower maximum flow pressure is set, results in the spring 18 being further expanded, i.e. the spring tension of the spring 18 is 5 reduced.

In the case of the valve 1, three different pressure settings are indicated by the markings 130 on the spring tension adjuster 92, namely 350, 500 and 600 kPa. Figure 1B shows the maximum flow pressure of the valve 1 set to 350 kPa and Figure 1D shows the maximum flow pressure of the valve set to 600 kPa, since 10 those respective pressure markings 130 are aligned with the portion 106b of the marker 106 in Figures 1B and 1D. The valve 1 may be supplied from the factory set at a particular maximum flow pressure, e.g. 500 kPa, and the maximum flow pressure may be subsequently adjusted, if required, at the time of installation of the valve 1. The maximum flow pressure to which the valve 1 is adjusted, 15 indicates the maximum pressure, as measured at the outlet 14, of fluid that passes through the valve 1.

Overview of Use and Operation of the Valve 1

The valve 1 is connected into the fluid supply line by way of the screw threads 32 and 34. Fluid that flows in the supply line enters the valve 1 via the inlet 12 and 20 exits via the outlet 14. The pressure of fluid, at the outlet 14, which has passed through the valve 1, cannot exceed the maximum pressure to which the valve 1 has been set (i.e. the maximum pressure setting of the valve 1) by the adjuster 20. In addition, the valve 1 will remain in an open condition if the pressure of the fluid in the supply line, connected to the inlet 12, falls below the maximum 25 pressure to which the valve 1 has been set.

The piston member 16 is moveable in the body 10 between a fully open condition and a closed condition of the valve 1, as will be further described herein. The spring 18 biases the piston member 16 in the direction D to an open condition of the valve 1. An open condition of the valve 1 exists when the piston head 36 is 30 unseated from the valve seat 58. When the piston head 36 is unseated from the valve seat 58, the seal 46 of the piston head 36 is unseated from the seating surface 68 of the valve seat 58, i.e. the piston head 36 is not in contact with the seating surface 68. In an open condition of the valve 1, a fluid flow path is formed 18 2013205201 04 Jan 2017 through the body 10 of the valve 1 between the inlet 12 and the outlet 14. The fluid flow path extends from the inlet 12 to the outlet 14, as will be further described herein. The fully open condition of the valve 1 occurs when the piston member 16 has moved within the body 10, in the direction D, such that it is 5 unable to move any further in the direction D. The piston member 16 is unable to move any further in the direction D when the shoulder 48 of the piston member 16 abuts against the flange 80 of the piston housing 56. Once the shoulder 48 abuts against the flange 80, further movement of the piston member 16 in the direction D is not possible. The maximum possible spacing between the piston head 36 10 and the seating surface 68 of the valve seat 58 occurs when the shoulder 48 abuts against the flange 80, i.e. when the valve 1 is in the fully open condition.

The fully open condition of the valve 1 is shown in Figures 1E and 1F.

Open Condition of the Valve 1

In an open condition of the valve 1, a fluid flow path is formed through the body 15 10 of the valve 1 between the inlet body part 22 and the outlet body part 24. The fluid flow path extends from the inlet 12, through the inlet body part 22, the passage 142, the opening 70 in the valve seat 58, around the piston head 36, and into the outlet body part 24 and ends at the outlet 14. A portion of the fluid flow path is provided around the spring chamber 134 and is 20 exterior of the spring chamber 134. This portion of the fluid flow path is also provided around the spring 18 and is exterior of the spring 18. This portion of the fluid flow path is also provided around the piston housing 56 and is exterior of the piston housing 56. This portion of the fluid flow path is the portion formed substantially by the passage 142. 25 The spring 18 and the portion of the fluid flow path that is provided around and exterior of the spring chamber 134 (and around and exterior of the spring 18) may be arranged such that they are substantially coaxial.

The arrangement of the valve 1, in which a portion of the fluid flow path is provided around the spring chamber 134 and exterior of the spring chamber 134, 30 as herein before described, means that a spring 18 of relatively small diameter may be used. 19 2013205201 04 Jan 2017

The shapes of the valve seat 58 and the curved surface 50 of the neck 40 result in the fluid flow path, at the region of the opening 70 in the valve seat 58, having a cross-sectional area that is substantially similar to the cross-sectional area of the remainder of the fluid flow path from the end of the spring tension adjuster 92, in 5 the inlet body part 22, to the piston head 36 in the fully open condition of the valve 1. This is best seen in Figures 1E and 1F. Thus, the fluid flow path through the valve 1 has a substantially constant cross-section from the first end 100 of the spring tension adjuster 92, through the passage 142 and to the piston head 36 in the fully open condition of the valve 1. This substantially constant cross-section 10 results in a relatively smooth flow of fluid through the fluid flow path in the valve 1.

Closed Condition of the Valve 1

In the closed condition of the valve 1, the piston head 36 seats on valve seat 58 such that the seal 46 is in sealing contact with the seating surface 68 of the valve seat 58. In the closed condition of the valve 1, the seal 46 normally wedges 15 against and seats on the chamfered portion 72 of the seating surface 68 at the region adjacent the adjoining surface 74. However, it may seat on the adjoining surface 74 under some conditions such as, for example, in the event of a shock pressure rise on the downstream side of the valve seat 58. The closed condition of the valve 1 is shown in Figures 1G and 1H. In the closed condition of the valve 20 1, the fluid cannot pass through the opening 70 of the valve seat 58. Accordingly, in the closed condition of the valve 1, there is no fluid flow path that extends between the inlet 12 and the outlet 14 since the opening 70 of the valve seat 58 is closed off by the piston head 36.

In the closed condition of the valve 1, fluid on the upstream side of the valve seat 25 58 is separated from fluid on the downstream side of the valve seat 58.

Use and Operation in Open Condition

In use, once flow of fluid commences through the fluid supply line (in which the valve 1 is connected), fluid flows into the valve 1 via the inlet 12. Flow of fluid through the fluid supply line may be commenced, for example, by opening a fluid 30 outlet device (such as a tap) downstream of the valve 1. A fluid flow path is formed that extends between the inlet 12 and the outlet 14 through the body 10 of the valve 1, as will be now described. The fluid enters the body 10 of the valve 1 20 2013205201 04 Jan 2017 via the inlet 12 and passes into the inlet body part 22, and then into the passage 142. The biasing action of the spring 18 on the piston member 16, in the direction D, and the pressure of the fluid flowing into the valve 1, in the direction D, maintain the piston head 36 in a condition in which the seal 46 is unseated from 5 the seating surface 68 of the valve seat 58, i.e. the valve 1 is maintained in an open condition, with the piston head 36 on the downstream side of the valve seat 58. Consequently, the fluid is able to flow from the upstream side of the valve seat 58, through the opening 70, in the valve seat 58, and around the piston head 36 into the outlet part 14 on the downstream side of the valve seat 58. The fluid exits 10 the body 10 of the valve 1 via the outlet 14. In this way, a fluid flow path is formed which extends between the inlet 12 and the outlet 140 in an open condition of the valve 1.

In the event that the pressure of the fluid entering the valve 1, via the inlet 12 at the inlet body part 22, falls below the maximum flow pressure to which the valve 1 15 has been adjusted, the spring 18 still continues to bias the piston member 16 in the direction D such that the piston head 36 remains unseated from the seating surface 68 of the valve seat 58. Accordingly, the valve 1 remains in an open condition even if the pressure of the fluid entering the valve 1 falls below the maximum flow pressure to which the valve 1 has been adjusted. 20 Use and Operation in Closed Condition

Flow of fluid through the fluid supply line (in which the valve 1 is connected) may be stopped, for example, by closing the fluid outlet device. When this occurs, the back pressure of the fluid in the fluid supply line on the downstream side of the valve 1 (i.e. downstream of the outlet 14) acts in the direction opposed to the 25 direction D (i.e. in the upstream direction) against the biasing action of the spring 18. (The back pressure of the fluid in the fluid supply line on the downstream side of the valve seat 58 is also referred to herein as the downstream fluid pressure.) This back pressure acts on the piston head 36 to move the piston member 16 in the direction opposed to the direction D until the piston head 36 seats on the 30 valve seat 58 with the seal 46 of the piston head 36 seating, in sealing contact, on the seating surface 68 of the valve seat 58 to close the valve 1. The seating surface 68 is provided at the downstream side of the valve seat 58. In the closed condition of the valve 1, the seal 46 normally wedges against and seats on the 21 2013205201 04 Jan 2017 chamfered portion 72 of the seating surface 68 at the region adjacent the adjoining surface portion 74. However, it may seat on the adjoining surface portion 74 under some conditions such as, for example, in the event of a shock pressure rise on the downstream side of the valve seat 58. 5 In the closed condition of the valve 1, the downstream fluid pressure acts to counter the spring force of the spring 18 that acts to bias the piston member 16 to unseat the piston head 16 from the valve seat 58. In addition, in the closed condition of the valve 1, this downstream fluid pressure, that acts to counter the spring force, acts only on the piston head 36. The transverse cross-sectional area 10 of the surface of the piston head 36, on which the downstream fluid pressure acts, extends from the centre line of the piston head 36 to the outer edge of the piston head 36.

In the closed condition of the valve 1, the fluid cannot pass through the opening 70 of the valve seat 58. Accordingly, in the closed condition of the valve 1, there 15 is no flow path that extends between the inlet 12 and the outlet 14 since the opening 70 of the valve seat 58 is closed off by the piston head 36.

Lowest Maximum Flow Pressure Setting

Figures 1E and 1G show the valve 1 in an open condition and a closed condition, respectively, with the maximum flow pressure of the valve 1 set to its lowest 20 setting. At the lowest maximum flow pressure setting of the valve 1, the spring tension adjuster 92 is at its minimum insertion into the piston housing 56.

The spring 18 is at its maximum expanded condition in the spring chamber 134 when the maximum flow pressure is set to its lowest setting and the valve 1 is in the fully open condition, which is shown in Figure 1E. When the valve 1 switches 25 from its open condition to its closed condition, the back pressure of the fluid acts on the piston member 16, against the biasing action of the spring 18, and consequently results in compression of the spring 18. The piston member 16 moves in the direction opposed to the direction D until the piston head 36 seats on the valve seat 58 such that the valve 1 is in its closed condition. 30 Highest Maximum Flow Pressure Setting 22 2013205201 04 Jan 2017

Figures 1F and 1H show the valve 1 in an open condition and a closed condition, respectively, with the maximum flow pressure of the valve 1 set to its highest setting. At the highest maximum flow pressure setting of the valve 1, the spring tension adjuster 92 is at its maximum insertion into the piston housing 56. 5 When the valve 1 is set to its highest maximum pressure setting, the spring 18 is compressed in the spring chamber 134. When the valve 1 switches from its open condition to its closed condition, the back pressure of the fluid acts on the piston member 16, against the biasing action of the spring 18, and consequently results in further compression of the spring 18. The piston member 16 moves in the 10 direction opposed to the direction D until the piston head 36 seats on the valve seat 58 such that the valve 1 is in its closed condition. The spring 18 is at its maximum compressed condition in the spring chamber 134 when the maximum flow pressure is set to its highest setting and the valve 1 is in the closed condition, which is shown in Figure 1H.

15 OTHER VALVES WITH ADJUSTABLE MAXIMUM FLOW PRESSURE

In the followings sections, embodiments of other valves with adjustable maximum flow pressure are described. These valves have different types of mechanisms to adjust the maximum flow pressure.

SECOND EMBODIMENT 20 In Figures 2A to 21 of the drawings, there is shown an embodiment (also referred to herein as the second embodiment) of a valve 2 with adjustable maximum flow pressure.

The valve 2 has many parts that are similar to those of the valve 1 of the first embodiment. The drawings of the first and second embodiments of the valves 1 25 and 2 use the same reference numerals to denote the same parts. Those parts will not again be described with reference to the valve 2 of the second embodiment. It is to be understood that the description of such parts with reference to the valve 1 of the first embodiment also applies to the valve 2 of the second embodiment. Accordingly, the description of the valve 2 will focus on the 30 aspects of the valve 2 that are different from the valve 1.

Body 160 23 2013205201 04 Jan 2017

The valve 2 has a body 160 that comprises a first, or inlet, body part 162 and a second, or outlet, body 164. The inlet body part 162 and the outlet body part 164 are connected in a manner similar to the inlet body part 22 and the outlet body part 24 of the first embodiment, by respective screw threads 26 and 28. 5 The inlet body part 162 is provided with an opening in the form slot 166. The slot 166 extends in a circumferential direction partly around the inlet body part 162. The inlet body part 162 is also provided with several depressions 168 in its outer surface. The depressions 168 are spaced apart circumferentially on the outer surface of the inlet body part 162. The first and last depressions 168 may be 10 aligned with the respective ends of the slot 166.

The inlet body part 162 is provided with grooves 170 and 172 on respective sides of the slot 166. Respective seals 174 are provided in the grooves 170 and 172. The seals 174 may be O-rings.

Piston Member 16a 15 The valve 2 has a piston member 16a that is substantially identical to the piston member 16 of the valve 1 of the first embodiment, except that the piston member 16a is not provided with a shoulder 48. In other respects, the piston member 16a is the same as the piston member 16 of the valve 1 of the first embodiment.

Piston Housing 176 and Valve Seat 178 20 The valve 2 has a piston housing 176 and a valve seat 178. Whilst the piston housing 56 and the valve seat 58 of the valve 1 of the first embodiment are provided as a combination housing unit 60, the piston housing 176 and the valve seat 178 of the valve 2 are separate components.

The piston housing 176 comprises a substantially tubular, or sleeve-like, member 25 180 and a collar 182. The collar 182 is provided adjacent one end of the tubular member 180, being the end at which the opening 82 of the piston housing 176 is provided. The other end of the piston housing 176 is provided with an opening 84. The tubular member 180 and the collar 182 are connected by webs 184. A passage 186 is formed between the tubular member 180 and the collar 182 for 30 fluid flow. The passage 186 is substantially annular in cross-section. This passage 186 is divided into separate passage sections 186a, in the radial 24 2013205201 04 Jan 2017 direction, by the webs 184. The webs 184 may be substantially wedge-shaped and extend partly along the tubular member 180, away from the collar 182.

Whilst the piston housing 56 of the valve 1 of the first embodiment is provided with an inwardly turned flange 80, which acts as a stop to prevent movement of 5 the piston member 16 in the direction D, the valve 2 is provided with a separate piston stop 188. The piston stop 188 is located in the outlet body part 164. The piston stop 188 is substantially annular and has a central opening 190.

Whilst the valve seat 178 is a separate component, the valve seat 178 is of a similar structure to the valve seat 58 of the valve 1 of the first embodiment, as 10 hereinbefore described.

The piston stop 188 abuts the surface 146 of the outlet body part 164, the valve seat 178 abuts one side of the piston stop 188, and one side of the collar 182 of the piston housing 176 abuts the other side of the valve seat 178. In this way the valve seat 178 is sandwiched between the piston stop 188 and the piston housing 15 176. The other side of the collar 182 abuts the end of the inlet body part 162 that is adjacent the screw thread 26. Accordingly, the piston housing 176, valve seat 178 and the piston stop 188 are fixed and immovable in the body 160.

Adjuster 192

The valve 2 has an adjuster 192 to adjust the maximum flow pressure of fluid at 20 the outlet 14 of the valve 2. The adjuster 192 comprises a spring tension adjuster 194 and an adjustment ring 196.

Spring Tension Adjuster 194

The spring tension adjuster 194 is provided with a helical slot 198. The spring tension adjuster 194 is provided with openings 200 at a first end 100 thereof. The 25 openings 200 may be in the form of arcuate slots. A hub 202 extends centrally in the spring tension adjuster 194. The hub 202 is closed at the first end 100 of the spring tension adjuster 194 and is open at the second end 108 of the spring tension adjuster 194. A recess 204 is provided in the hub 202. The recess 204 is accessible at the second end 108 of the spring tension adjuster 194. A seal 206 is 30 provided in a groove in the hub 202 adjacent the second end 108. 25 2013205201 04 Jan 2017 A portion of the hub 202, adjacent the second end 108 thereof, is received inside the space 86 of the tubular member 180, of the piston housing 176, via the opening 84 of the tubular member 180 of the piston housing 176. The seal 206 seals against the internal surface of the tubular member 180 to prevent fluid 5 leaking between the hub 202 and the internal surface of the tubular member 180.

The spring tension adjuster 194 is provided with a channel 208. The channel 208 extends in a substantially axial direction. A guide pin 210 extends through an aperture in the inlet body part 162 and is received in the channel 208. This arrangement prevents the spring tension adjuster 194 rotating in the body 160. ίο Adjustment Ring 196

The adjustment ring 196 is provided around the inlet body part 162. The seals 174, on the inlet body part 162, seal against the internal surface of the adjustment ring 196 to prevent fluid leaking from the interior of the body 160.

The adjustment ring 196 is provided with first and second engagement members, 15 which may be in the form of screws 212 and 214, which extend into the adjustment ring 196 from the exterior thereof. The first screw 212 is received in the helical slot 198 of the spring tension adjuster 194. The second screw 214 bears against a spring 216, which in turn bears against a small ball 218 that is received in one of the depressions 168. 20 The exterior surface of the outlet body part 164 is provided with markings 130 to indicate the maximum flow pressure to which the valve 2 can be set. These markings 130 are best seen in Figures 2A to 2D, where the markings 130 for the pressures of 350, 500 and 600 kPa are shown. The adjustment ring 196 is provided with an indicator 130a which points to one of the markings 130 to 25 indicate the maximum flow pressure to which the valve 2 has been set.

The cavity 42 (of the piston member 16a), the recess 204 (in the hub 202 of the spring tension adjuster 194) and the space 86 inside the piston housing 176 together form a spring chamber 134. The spring 18 extends from a shoulder 138, in the cavity 42 of the piston member 16a, to a shoulder 220 of the recess 204. 30 The seals 54 and 206 prevent water entering the spring chamber 134. 26 2013205201 04 Jan 2017 A passage 142 is formed between the outer surfaces of the piston housing 176 and the spring tension adjuster 194, and the inner surfaces of the inlet body part 162 and the outlet body part 164. The passage 142 is substantially annular in cross-section, and is substantially in the form of an annular cylinder.

5 USE AND OPERATION OF THE SECOND EMBODIMENT

The manner of use and operation of the valve 2 of the second embodiment is substantially the same as for the valve 1 of the first embodiment and so will not again be described herein. The difference in the operation between the valve 2 of the second embodiment and the valve 1 of the first embodiment is in relation to 10 the operation of the adjuster 192 of the valve 2 of the second embodiment.

Accordingly, the description of the use and operation of the valve 2 will focus on the use and operation of the adjuster 192.

Adjusting the Maximum Flow Pressure

The adjuster 192 may be used to adjust the maximum flow pressure of the valve 15 2 either before or after installation of the valve 2 in a fluid supply line such as, for example, the supply line to a hot water heater. The maximum flow pressure setting of the valve 2 may be adjusted by turning the adjustment ring 196 in the required direction, with reference to the markings 130 so as to align the indicator 130a with the marking 130 of the required maximum flow pressure. 20 The spring tension adjuster 194 is able to move relative to the piston housing 176. Since the pin 210 is received in the channel 208 of the spring tension adjuster 194, this movement of the spring tension adjuster 194 is a liner movement relative to the piston housing 176. The linear movement is parallel to the direction D, i.e. parallel to the axial line of the valve 2. The relative linear movement between the 25 spring tension adjuster 194 and the piston housing 176 is substantially parallel to the coaxial line of the inlet 12 and the outlet 14, represented by the broken line L. When the adjustment ring 196 is turned, the small ball 218 is moved out of the depression 168, in which it is located, compressing the spring 216, and moves along the exterior surface of the inlet body part 162. A depression 168 is provided 30 to correspond with each pressure marking 130. Simultaneously, the screw 212, which engages in the helical slot 198, causes the spring tension adjuster 194 to move in a linear manner. The linear movement of the spring tension adjuster 194 27 2013205201 04 Jan 2017 results in the spring tension adjuster 194 being moved either toward or away from the piston housing 176. Correspondingly, this results in the hub 202 being moved further into, or out of, the substantially tubular .member 180 of the piston housing 176. This movement of the spring tension adjuster 194 results in the size of the 5 spring chamber 134 being either decreased or increased, by shortening or lengthening its length. The linear movement of the spring tension adjuster 194 results in the spring 18 being either compressed or expanded, depending upon the direction of rotation of the adjustment ring 196. That is to say, the spring tension of the spring 18 is either increased or decreased, depending upon the 10 direction of rotation of the adjustment ring 196, since rotation of the adjustment ring 196 alters the size of the spring chamber 134. Rotating the adjustment ring 196 in the direction such that a higher maximum flow pressure is set, results in the spring 18 being further compressed, i.e. the spring tension of the spring 18 is increased. On the other hand, rotating the adjustment ring 196 in the direction 15 such that a lower maximum flow pressure is set, results in the spring 18 being further expanded, i.e. the spring tension of the spring 18 is reduced.

The adjustment ring 196 is turned until the required maximum flow pressure is set. That is, until the small ball 218 is received in the next depression 168, which signifies that the corresponding maximum flow pressure has been set. 20 In the case of the valve 2, three different pressure settings are indicated by the markings 130 on the outlet body part 164, namely 350, 500 and 600 kPa. Consequently, a depression 168 is provided on the inlet body part 162 corresponding to each of these pressure settings.

Figure 2A shows the maximum flow pressure of the valve 2 set to 350 kPa and 25 Figure 2D shows the maximum flow pressure of the valve 2 set to 600 kPa, since those respective pressure markings 130 are aligned with the indicator 130a in Figures 2A and 2D.

In an open condition of the valve 2, a fluid flow path is formed through the body 160 of the valve 2 between the inlet body part 162 and the outlet body part 164. 30 The fluid flow path extends from the inlet 12, through the inlet body part 162, the passage 142, the opening 70 in the valve seat 178, around the piston head 36, and into the outlet body part 164 and ends at the outlet 14. 28 2013205201 04 Jan 2017

In other respects, the use and operation of the valve 2 is similar to the use and operation of the valve 1 of the first embodiment hereinbefore described.

THIRD EMBODIMENT

In Figures 3A to 3I of the drawings, there is shown an embodiment (also referred 5 to herein as the third embodiment) of a valve 3 with adjustable maximum flow pressure.

The valve 3 has many parts that are similar to those of the valves of the embodiments previously described herein. The drawings of the embodiments previously described herein and the drawings of the third embodiment use the 10 same reference numerals to denote the same parts. Those parts will not again be described with reference to the valve 3 of the third embodiment. It is to be understood that the description of such parts with reference to the valves of the embodiments previously described herein also applies to the valve 3 of the third embodiment. Accordingly, the description of the valve 3 will focus on the aspects 15 of the valve 3 that are different from the valves of the embodiments previously described herein.

Body 260

The valve 3 has a body 260 that comprises a first, or inlet, body part 262 and a second, or outlet, body 264. The end of the outlet part 264 that is opposed to the 20 outlet 14 is received in the opening at the end of the inlet body part 262 that is opposed to the inlet 12. However, unlike the valves 1 and 2 of the first and second embodiments, the inlet body part 262 and the outlet body part 264 of the valve 3 are not connected by screw threads 26 and 28.

The inlet body part 262 and the outlet body part 264 are provided with respective 25 lugs 266 and 268. Each lug 266 and 268 has a respective aperture 270a and 270b extending therethrough. The aperture 270b is provided with an internal screw thread 272. The apertures 270a and 270b are aligned. A pin, or screw, 274 extends through the apertures 270a and 270b. The end of the pin 274 protrudes through the aperture 270a. The pin 274 has screw thread 276 that engages with 30 the screw thread 272 in the aperture 270b. A circlip 278 is retained at the end of the pin 274. The circlip 278 prevents the pin 274 being unscrewed and removed from the apertures 270a and 270b. The pin 274 may be turned in either direction, 29 2013205201 04 Jan 2017 which results in the inlet body part 262 and the outlet body part 264 being moved either toward or away from each other, as will be further described herein. However, due to the pin 274 being retained in the apertures 270a and 270b, the inlet body part 262 and the outlet body part 264 are retained together. 5 The exterior surface of the outlet body part 264 is provided with markings 130 for the purpose previously herein before described with reference to the first and second embodiments.

The interior surface of the outlet body part 264 is provided with a screw thread 279. io The end of the inlet body portion 262 that is opposed to the inlet 12 forms the indicator 130a of the valve 3.

Piston Member 16b

The valve 3 has a piston member 16b that is substantially identical to the piston member 16 of the valve 1 of the first embodiment. 15 Piston Housing 280 and Valve Seat 282

The valve 3 has a piston housing 280 and a valve seat 282.

The piston housing 280 comprises a substantially tubular, or sleeve-like, member 284 and a collar 286. The collar 286 extends beyond the end of the tubular member 284 at which the opening 82 is located. In addition, the tubular member 20 284 is provided with an inwardly turned flange 80 that surrounds the opening 82 of the tubular member 284 of the piston housing 280.

The tubular member 284 and the collar 286 are connected by webs 184a, in a manner similar to the webs 184 that connect the tubular member 180 and the collar 182 of the piston housing 176, to form a passage 186 and separate 25 passage sections 186a between respective webs 184a.

The inwardly turned flange 80 acts as a stop to prevent movement of the piston member 16b in the direction D in a similar manner to the inwardly turned flange 80 of the piston housing 56 of the valve 1 of the first embodiment. 30 2013205201 04 Jan 2017

The valve seat 282 is of a substantially similar form as the valve seat 178 of the valve 2 of the second embodiment.

The valve seat 282 is a separate component similar to the valve seat 178 of the valve 2 of the second embodiment. 5 The valve seat 282 abuts the surface 146a of the outlet body part 264, the end of the collar 286 (nearest the opening 82) abuts one side of the valve seat 282 and a retainer member 287 abuts the other end of the collar 286. The retainer member 287 is substantially annular, in the form of a ring. The retainer member 287 is provided with a screw thread 288 on its outer surface. The screw thread 288 is 10 engaged with the screw thread 279 in the outlet body part 264. Accordingly, the piston housing 266, is sandwiched between the valve seat 282 and the retainer member 287. Consequently, the piston housing 280 and the valve seat 282 are fixed and immoveable in the body 260.

Adjuster 296 15 The valve 3 has an adjuster 296 to adjust the maximum flow pressure of fluid at the outlet 14 of the valve 3. The adjuster 296 comprises a spring tension adjuster 298 and an adjustment mechanism 300.

Spring Tension Adjuster 298

The spring tension adjuster 298 is of a substantially similar form as the spring 20 tension adjuster 194 of the valve 2 of the second embodiment. The spring tension adjuster 298 is provided with openings 200 at a first end 100 thereof. A hub 202a extends centrally in the spring tension adjuster 298 and is open at the second end 108 of the spring tension adjuster 298. A recess 204a is provided in the hub 202a. The recess 204a is accessible at the second end 108 of the spring tension 25 adjuster 298. A seal 206 is provided in a groove in the hub 202a adjacent the second end 108. A portion of the hub 202a is received inside the space 86 of the tubular member 284 in a manner similar to that previously described herein in relation to the spring tension adjuster 194 of the valve 2 of the second embodiment. 30 The spring tension adjuster 298 is fixed in the inlet body part 262. This is done by way of a circlip 302 engaging in a groove in the internal surface of the inlet body 31 2013205201 04 Jan 2017 part 262. A collar-like portion 303 of the spring tension adjuster 298 is retained between a surface 304 of the inlet body part 262 and the circlip 302.

Adjustment Mechanism 300

The adjustment mechanism 300 comprises the lugs 266 and 268 and the pin 274 5 that extends between these lugs 266 and 268.

The adjustment mechanism forms a connection that connects the inlet body part 262 and the outlet body part 264 which are able to move relative to one another in a linear direction parallel to the direction D.

In addition, a spring chamber 134 is provided in a manner similar to that 10 hereinbefore described with reference to the valve 2 of the second embodiment. The seals 54 and 206 prevent water entering the spring chamber 134.

Similarly, a passage 142 is formed in the body 260 of the valve 3 in a manner similar to that hereinbefore described with reference to the valve 2 of the second embodiment.

15 USE AND OPERATION OF THE THIRD EMBODIMENT

The manner of use and operation of the valve 3 of the third embodiment is substantially similar as for the valves 1 and 2 of the first and second embodiments and so will not again be described herein. The difference in the operation between the valve 3 of the third embodiment and the valves 1 and 2 of the first 20 and second embodiments is in relation to the operation of the adjuster 296 of the valve 3. Accordingly, the description of the use and operation of the valve 3 will focus on the use and operation of the adjuster 296.

Adjusting the Maximum Flow Pressure

The adjuster 296 may be used to adjust the maximum flow pressure of the valve 25 3 before installation of the valve 3 in a fluid supply line such as, for example, the supply line to a hot water heater. The maximum flow pressure setting of the valve 3 may be adjusted by turning the pin 274 in the required direction, until the marking 130 of the required maximum flow pressure is aligned with the indicator 130a. 32 2013205201 04 Jan 2017

In contrast to the valves 1 and 2 of the first and second embodiments, the spring tension adjuster 298 is fixed in the body 260, in particular, in the inlet body part 262. Turning the pin 274 causes the inlet body part 262 and the outlet body part 264 to move either toward or away from one another, depending upon the 5 direction in which the pin 274 is turned. Since the piston housing 280 is fixed in the outlet body part 264, movement of the inlet body part 262 and the outlet body part 264 results in relative movement between the spring tension adjuster 298 and the piston housing 280.

The rotational movement of the pin 274 results in a linear movement of the inlet 10 body part 262 and the outlet body part 264 relative to one another. This linear movement is parallel to the direction D, i.e. parallel to the axial line of the valve 3.

The linear movement of the inlet body part 262 and the outlet body part 264 results in a corresponding linear movement of the piston housing 280 relative to the spring tension adjuster 298. The linear movement is parallel to the direction D, 15 i.e. parallel to the axial line of the valve 3. The relative linear movement between the spring tension adjuster 298 and the piston housing 280 is substantially parallel to the coaxial line of the inlet 12 and the outlet 14, represented by the broken line L. This linear movement results in the piston housing 280 and the spring tension adjuster 298 being moved either toward or away from one another. 20 Correspondingly, this results in the hub 202a of the spring tension adjuster 298 being moved further into, or out of, the tubular member 284 of the piston housing 280. This movement results in the size of the spring chamber 134 being either decreased or increased, by shortening or lengthening its length. The relative linear movement of the piston housing 280 and the spring tension adjuster 298 25 results in the spring 18 being either compressed or expanded, depending upon the direction of the rotation of the pin 274. That is to say, the spring tension of the spring 18 is increased or decreased, depending upon the direction of rotation of the pin 274, since rotation of the pin 274 results in the size of the spring chamber 134 being altered. Rotating the pin 274 in the direction such that a higher 30 maximum flow pressure is set results in the spring 18 being further compressed, i.e. the spring tension of the spring 18 is increased. On the other hand, rotating the pin 274 in the direction such that a lower maximum flow pressure is set, results in the spring 18 being further expanded, i.e. the spring tension of the spring 18 is reduced. 33 2013205201 04 Jan 2017

The pin 274 is rotated until the required maximum flow pressure is set. That is, until the required maximum flow pressure marking 130 is aligned with the indicator 130a.

In the case of the valve 3, three different pressure settings are indicated by the 5 markings 130 on the outlet body part 264, namely 350, 500 and 600 kPa.

Figures 3A and 3B show the maximum flow pressure of the valve 3 set to 350 kPa and Figures 2C and 2D show the maximum flow pressure of the valve 3 set to 600 kPa, since those respective pressure markings 130 are aligned with the indicator 130a in Figures 3Ato 3D. 10 In an open condition of the valve 3, a fluid flow path is formed through the body 260 of the valve 3 between the inlet body part 262 and the outlet body part 264. The fluid flow path extends from the inlet 12, through the inlet body part 262, the passage 142, the opening 70 in the valve seat 282, around the piston head 36, and into the outlet body part 264 and ends at the outlet 14. 15 In other respects, the use and operation of the valve 3 of the third embodiment is similar to the use and operation of the valves 1 and 2 of the first and second embodiments hereinbefore described.

FOURTH EMBODIMENT

In Figures 4A to 4I of the drawings, there is shown an embodiment (also referred 20 to herein as the fourth embodiment) of a valve 4 with adjustable maximum flow pressure.

The valve 4 has many parts that are similar to those of the valves of the embodiments previously described herein. The drawings of the embodiments previously described herein use the same reference numerals to denote the same 25 parts. Those parts will not again be described with reference to the valve 4 of the fourth embodiment. It is to be understood that the description of such parts with reference to the valves of the embodiments previously described herein also applies to the valve 4 of the fourth embodiment. Accordingly, the description of the valve 4 will focus on the aspects of the valve 4 that are different from the 30 valves of the embodiments previously described herein.

Body 320 34 2013205201 04 Jan 2017

The valve 4 has a body 320 that comprises a first, or inlet, body part 322 and a second, or outlet, body 324. The inlet body part 322 and the outlet body part 324 are connected in a manner similar to the inlet body part 22 and the outlet body part 24 of the first embodiment, by respective screw threads 26 and 28. 5 The inlet body part 322 is provided with a screw thread 325 on its internal surface adjacent to the opening opposed to the inlet 12.

The outlet body part 324 is provided openings 326 spaced around its circumference. Three such openings 326 are provided. A screw thread 328 is provided on the exterior surface of the outlet body part 324. 10 The screw thread 328 is provided between the openings 326 and the screw thread 34 that is adjacent the outlet 14 of the valve 4.

The exterior surface of the outlet body part 324 is provided with markings 130 for the purpose previously herein before described with reference to the first, second and third embodiments. These markings 130 are best seen in Figures 4Ato 4C, 15 in which the markings 130 for the pressures of 350, 500 and 600 kPa are variously shown.

Piston Member 330

The valve 4 is provided with a piston member 330. The piston member 330 comprises a substantially tubular member 332 and a piston head 334 provided at 20 one end of the tubular member 332. The piston head 334 has internal surfaces 334a and 334b. The piston head 334 is provided with a pair of grooves 336. Respective seals 338 are located in the grooves 336. The seals 338 may be O-rings. The seals 338 seal against the internal surface of the outlet body part 324 to ensure that fluid cannot leak between the internal wall of the outlet body part 25 324 and the piston head 334.

An opening 339a is provided at the end of the tubular member 332 that is spaced from the piston head 334. An opening 339b is provided at the other end of the piston member 330 at which the piston head 334 is provided. The openings 339a and 339b are in fluid communication such that fluid can flow through the piston 30 member 330, since the interior of the piston member 330 defines a hollow space 330a. 35 2013205201 04 Jan 2017

Piston Housing 340

The piston member 330 is housed, or retained, by a piston housing 340. The piston housing 340 is substantially tubular, or sleeve-like. The piston housing 340 has respective openings 82 and 84 at its respective ends. A space 86 is provided 5 inside the piston housing 340.

The piston housing 340 and the inlet body part 322 are connected. The piston housing 340 is provided with a screw thread 342 at its exterior surface. The screw thread 342 engages with the screw thread 325 in the inlet body part 322 to thereby connect the piston housing 340 and the inlet body part 322. 10 Consequently, the piston housing 340 is fixed and immovable in the body 320.

Openings 344 are provided in the piston housing 340, around the circumference of the piston housing 340. The openings 344 are provided between the end of the piston housing 340, at which the opening 84 is provided, and the screw thread 342. A flange 346 extends around the exterior surface of the piston housing 340. 15 The flange 346 abuts the end of the inlet body part 322. A seal 350 is provided in a groove that is provided between the screw thread 342 and the flange 346 at the exterior surface of the piston housing 340. The seal 350 may be an O-ring. The seal 350 seals against the internal surface of the inlet body part 322 to ensure that fluid cannot leak between the inlet body part 322 and the piston housing 340. 20 The piston housing 340 is provided with a pair of grooves, at its internal surface, in which respective seals 354 are located. The seals 354 may be O-rings. The seals 354 ensure that fluid cannot leak between the piston member 330 and the piston housing 340.

The piston housing 340 is provided a screw thread 352 on its internal wall 25 adjacent the opening 84. The opening 84 of the piston housing 340 is closed off by a cap 356 which has a screw thread 358 that engages with the screw thread 352 of the piston housing 340. The cap 356 is provided with a seal 360 positioned inside the piston housing 340.

The end of the tubular member 332, having the opening 339a, and the seal 360 30 form a valve member and valve seat arrangement such that when that end of the tubular member 332 seats on the seal 360, the valve 4 is in a closed condition. 36 2013205201 04 Jan 2017

When that end of the tubular member 332 is unseated from the seal 360, the valve 4 is in an open condition.

Adjuster 362

The valve 4 has an adjuster 362 to adjust the maximum flow pressure of fluid at 5 the outlet 14 of the valve 4. The adjuster 362 comprises a spring tension adjuster 364 and an adjustment collar 366.

Spring Tension Adjuster 364

The spring tension adjuster 364 is substantially in the form of a triangular plate having truncated apexes 368. An aperture 370 is provided in the spring tension 10 adjuster 364. The truncated apexes 368 extend through respective openings 326 in the outlet body part 324. The spring 18a is provided around the tubular member 332. One end of the spring 18a bears against the piston head 334 whilst the other end of the spring 18a bears against the spring tension adjuster 364.

Adjustment Collar 366 15 The adjustment collar 366 is provided around the outlet body part 324. The adjustment collar 366 is provided with an internal screw thread 372 which engages with the screw thread 328 around the outlet body part 324. A circlip 374 is provided at the internal surface of adjustment collar 366 adjacent an end 376 of the adjustment collar 366. The truncated apexes 368 of the spring tension 20 adjuster 364 extend through the openings 326 between the screw thread 372 and the circlip 374. In this way, the adjuster 362 is retained with the adjustment collar 366.

The screw threaded engagement between the adjustment collar 366 and the outlet body part 324 means that the adjustment collar 366 may be rotated relative 25 to the outlet body part 324 to thereby move the adjustment collar 366 in a linear direction relative to the outlet body part 324. Since the spring tension adjuster 364 is retained with the adjustment collar 366, this also means that the retainer 362 is able to move in a linear direction with the adjustment collar 366.

The other end 378 of the adjustment collar 366 forms an indicator 130c which can 30 be aligned with the marking 130 of the required maximum flow pressure to be set. 37 2013205201 04 Jan 2017 A spring chamber 134a is formed in the annular space between the substantially tubular member 332 and the internal surface of the outlet body part 324, and extends between the piston head 334 and the spring tension adjuster 364. A passage 142 is formed in the body 320 of the valve 4 from the inlet 12 to the 5 openings 344 in the piston housing 340.

USE AND OPERATION OF THE FOURTH EMBODIMENT

The manner of use and operation of the valve 4 of the fourth embodiment is generally similar as for the valves 1,2 and 3 of first, second and third embodiments, and so will not again be described herein. The difference in the 10 operation between the valve 4 of the fourth embodiment and valves 1, 2 and 3 of the first, second and third embodiments is in relation to the operation of the adjuster 362, the valve seat arrangement, spring chamber 134a and the fluid flow path through the valve 4. Accordingly, the description of the use and operation of the valve 4 will focus on these aspects of the valve 4. is Adjusting the Maximum Flow Pressure

The adjuster 362 may be used to adjust the maximum flow pressure of the valve 4 either before or after installation of the valve 4 in a fluid supply line such as, for example, the supply line to a hot water heater. The maximum flow pressure seating of the valve 4 may be adjusted by turning the adjustment collar 366 in the 20 required direction, with reference to the markings 130, so as to align the indicator 130c with the marking 130 of the required maximum flow pressure.

The spring tension adjuster 364 is able to move relative to the piston housing 340. The rotational movement of the adjustment collar 366 results in a linear movement of the spring tension adjuster 364 relative to the piston housing 340. 25 The linear movement is parallel to the direction D, i.e. parallel to the axial line of the valve 4. The relative linear movement between the spring tension adjuster 364 and the piston housing 340 is substantially parallel to the coaxial line of the inlet 12 and the outlet 14, represented by the broken line L. The linear movement of the spring tension adjuster 364 results in the spring tension adjuster 364 being 30 moved either toward, or away from, the piston housing 340. In that regard, the portion of the piston housing 340 between the flange 346 and the end of the piston housing 340, at which the opening 82 is provided, is received in the 38 2013205201 04 Jan 2017 aperture 370 of the spring tension adjuster 364. That is to say, the linear movement of the spring tension adjuster 364 means that the spring tension adjuster 364 is able to move between the flange 346 and the end of the piston housing 340, at which the opening 82 is provided. This movement of the spring 5 tension adjuster 364 results in the size of the spring chamber 134a being either decreased or increased, by shortening or lengthening its length. The linear movement of the spring tension adjuster 364 results in the spring 18a being either compressed or expanded depending upon the direction of rotation of the adjustment collar 366. That is to say, the spring tension of the spring 18a is either 10 increased or decreased, depending upon the direction of rotation of the adjustment collar 366, which rotation causes the spring tension adjuster 364 to be moved in a first, or second linear direction that is parallel to the direction D. The linear movement of the spring tension adjuster 364 results in the spring 18a being either compressed or expanded depending upon the direction of movement of the 15 spring tension adjuster 364. That is to say, the spring tension of the spring 18a is either increased or decreased depending upon the direction of movement of the spring tension adjuster 364, since movement of the spring tension adjuster 364 alters the size of the spring chamber 134a. Moving the spring tension adjuster 364 in the direction such that a higher maximum flow pressure is set, results in 20 the spring 18a being further compressed, i.e. the spring tension of the spring 18a is increased. On the other, moving the spring tension adjuster 364 in the direction such that a lower maximum flow pressure is set, results in the spring 18a being further expanded, i.e. the spring tension of the spring 18a is reduced.

In the case of the valve 4, three difference pressure settings are indicated by the 25 markings 130 on the outlet body part 324, namely 350, 500 and 600 kPa.

Figures 4A and 4B show the maximum flow pressure of the valve 4 set to 350 kPa and Figures 4C and 4D show the maximum flow pressure of the valve 4 set to 600 kPa, since those respective pressure markings 130 are aligned with the indicator 130c in Figures 4A to 4D. 30 In an open condition of the valve 4, a fluid flow path is formed through the body 320 of the valve 4 between the inlet body part 322 and the outlet body part 324. The fluid flow path extends from the inlet 12, through the inlet body part 322, the passage 142, the openings 344 in the piston housing 340, through the space 86 39 2013205201 04 Jan 2017 in the piston housing, through the space 330a in the piston member 330, and into the outlet body part 324 and ends at the outlet 14.

Overview of Use and Operation of the Valve 4

The overview of the use and operation of the valve 1, as previously hereinbefore 5 described, also applies to the valve 4 of the fourth embodiment. The differences relate to the different arrangement of the opening and closing of the valve 4. In that regard, the spring 18a still biases the piston member 16b in the direction D to an open condition of the valve 4. An open condition of the valve 4 exists when the end of the substantially tubular member 332 of the piston member 330 is 10 unseated from the seal 360 provided on the cap 356. The fully open condition of the valve 4 occurs when the piston member 330 has moved within the body 320, in the direction D, such that it is unable to move any further in the direction D.

This occurs when the piston head 334 abuts against a shoulder 384 of the outlet body part 324. The maximum possible spacing between the end of the 15 substantially tubular member 332 and the seal 360 occurs when the valve 4 is in the fully open condition. The fully open condition of the valve 4 is shown in Figures 4E and 4F.

Open Condition of the Valve 4

In an open condition of the valve 4, a fluid flow path is formed through the body 20 320 of the valve 4 between the inlet 12 and the outlet 14, as previously hereinbefore described.

In contrast to the valves of the first, second and third embodiments, previously hereinbefore described, the fluid flow path of the valve 4 is not provided with a portion around the spring chamber 134a and exterior of the spring chamber 134a. 25 In contrast, in the valve 4, it is the spring chamber 134a that is provided around the portion of the fluid flow path. The spring 18a is also exterior of this portion of the fluid flow path. The piston housing 340 is also provided around this portion of the fluid flow path and the piston housing 340 is exterior of this portion of the fluid flow path. This portion of the fluid flow path is the portion formed from the region 30 of the openings 344 to the piston head 334.

The spring 18a and the portion of the fluid flow path, as previously hereinbefore described, may be arranged such that they are substantially coaxial. 40 2013205201 04 Jan 2017

Closed Condition of the Valve 4

In the closed condition of the valve 4, the end of the substantially tubular member 332 seats on the seal 360 provided on the cap 356. The closed condition of the valve 4 is shown in Figures 4G and 4H. In the closed condition of the valve 4, fluid 5 cannot pass through the openings 344 of the piston housing 340. Accordingly, in the closed condition of the valve 4, there is no fluid flow path that extends between the inlet 12 and the outlet 14 since the openings 344 are closed off due to the end of the substantially tubular member 332 seating on the seal 360.

In the closed condition of the valve 4, fluid on the upstream side of the seal 360 is 10 separated from fluid on the downstream side of the seal 360.

In the closed condition of the valve 4, the back pressure of the fluid in the fluid supply line on the downstream side of the seal 360 acts on the piston head 334 to move the piston member 330 in the direction opposed to the direction D such that the end of the substantially tubular member 332 seats on the seal 360. The 15 opening 339b at the end of the piston head 334 allows the back pressure of fluid in the fluid supply line to act on the internal surfaces 334a, 334b and 334c of the piston head 334.

The use and operation of the valve 4 in the open condition and in the closed condition is analogous to that hereinbefore described with reference to the valve 1 20 of the first embodiment.

Lowest Maximum Flow Pressure Setting

At the lowest maximum flow pressure setting of the valve 4, the spring tension adjuster 364 is substantially adjacent the flange 346 of the piston housing 340.

The spring 18a is at its maximum expanded condition in the spring chamber 134a 25 when the maximum flow pressure is set to its lowest setting and the valve 4 is in the fully open condition, which is shown in Figure 4E. When the valve 4 switches from its open condition to its closed condition, the back pressure of the fluid acts on the piston head 334, against the biasing action of the spring 18a, and consequently results in compression of the spring 18a. The piston member 330 30 moves in the direction opposed to the direction D until the end of the substantially 2013205201 04 Jan 2017 41 tubular member 332 seats on the seal 360 such that the valve 4 is in its closed condition.

Highest Maximum Flow Pressure Setting

At the highest maximum flow pressure setting of the valve 4, the spring tension 5 adjuster 364 is at its maximum spacing from the flange 346 of the piston housing 340.

When the valve 4 is set to its highest maximum flow pressure setting, the spring 18a is compressed in the spring chamber 134a. When the valve 4 switches from its open condition to its closed condition, the back pressure of the fluid acts on the 10 piston head 334, against the biasing action of the spring 18a, and consequently results in further compression of the spring 18a. The piston member 330 moves in the direction opposed to the direction D until the end of the substantially tubular member 332 seats on the seal 360 such that the valve 4 is in its closed condition. The spring 18a is at its maximum compressed condition in the spring chamber 15 134a when the maximum flow pressure is set to its highest setting and the valve 4 is in the closed condition, which is shown in Figure 4H.

Whilst preferred embodiments of the present invention have been herein before described, the scope of the present invention is not limited to those specific embodiments, and may be embodied in other ways, as will be apparent to a 20 skilled addressee.

Modifications and variations such as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

Claims (20)

1. The claims defining the invention are as follows:

   1. A valve comprising a body, an inlet for fluid to enter the body, an outlet for fluid to exit the body, a piston member moveable within the body, the piston member being retained by a piston housing, a spring to bias the piston member in a first direction, the inlet, the outlet and the spring are substantially coaxial, a fluid flow path which is formed through the body of the valve between the inlet and the outlet in an open condition of the valve, adjustment means to adjust the maximum flow pressure setting of the valve, the adjustment means comprising a spring tension adjuster and retainer means to retain the spring tension adjuster, such that the spring is located between the piston member and the spring tension adjuster, wherein the body comprises a first body part and a second body part that are detachably connected together, and wherein the piston housing is retained in the body of the valve and the retainer means is connected to the piston housing, and the spring tension adjuster is movable relative to the retainer means to cause compression or expansion of the spring, to increase or decrease tension of the spring, depending upon the direction of movement of the spring tension adjuster to adjust the spring force with which the spring biases the piston member in the first direction and thereby adjust the maximum flow pressure setting of the valve, and wherein the spring tension adjuster is provided with a helical groove and the retainer means is provided with a pin that is received in the helical groove such that the retainer means retains the spring tension adjuster, and wherein the spring biases the piston member in the first direction to an open condition of the valve, such that, in use, fluid is able to flow via the fluid flow path through the body of the valve between the inlet and the outlet and the maximum pressure setting of the valve determines the maximum pressure of fluid that, in use, is able to flow through the valve, from the inlet to the outlet, in an open condition of the valve.
2. 2. A valve according to claim 1, further comprising a valve seat, and the piston member is provided with a valve head that seats on the valve seat in a closed condition of the valve and unseats from the valve seat in an open condition of the valve.
3. 3. A valve according to any one of the preceding claims, wherein the piston housing houses at least a portion of the piston member.
4. 4. A valve according to any one of the preceding claims, wherein adjustment of the maximum flow pressure setting of the valve by the adjustment means results in relative movement between the spring tension adjuster and the piston housing.
5. 5. A valve according to claim 4, wherein the relative movement between the spring tension adjuster and the piston housing comprises movement of the spring tension adjuster in a linear direction that is substantially parallel to the coaxial line of the inlet and the outlet.
6. 6. A valve according to claim 4 or 5, wherein the relative movement between the spring tension adjuster and the piston housing comprises rotational movement of the spring tension adjuster.
7. 7. A valve according to any one of the preceding claims, wherein adjustment of the maximum flow pressure setting of the valve by the adjustment means results in relative movement between the spring tension adjuster and the retainer means.
8. 8. A valve according to claim 7, wherein the relative movement between the spring tension adjuster and the retainer means comprises movement of the spring tension adjuster in a linear direction that is substantially parallel to the coaxial line of the inlet and the outlet.
9. 9. A valve according to claim 7 or 8, wherein the relative movement between the spring tension adjuster and the retainer means comprises rotational movement of the spring tension adjuster.
10. 10. A valve according to any one of the preceding claims, wherein the spring is located between the spring tension adjuster and the piston housing.
11. 11. A valve according to any one of the preceding claims, wherein the valve further comprises visual indication means visible from exterior of the valve to indicate the maximum flow pressure to which the valve is set.
12. 12. A valve according to any one of the preceding claims wherein at least one seal is provided between the valve seat and the internal surface of the body of the valve.
13. 13. A valve according to any one of the preceding claims, wherein the piston housing and the adjustment means are provided as a single unit.
14. 14. A valve according to claim 13, wherein the single unit comprises a cartridge.
15. 15. A valve according to any one of the preceding claims, wherein the piston housing and the valve seat are provided as a single unit.
16. 16. A valve according to any one of the preceding claims, wherein the piston housing and the retainer means are substantially immovable relative to one another.
17. 17. A valve according to any one of the preceding claims, wherein the spring tension adjuster is engagable by a tool to rotate the spring tension adjuster to thereby adjust the maximum flow pressure setting of the valve.
18. 18. A valve according to any one of the preceding claims, wherein the retainer means is substantially tubular.
19. 19. A valve according to any one of the preceding claims, wherein the piston housing is prevented form rotating in the body of the valve.
20. 20. A valve substantially as herein before described with reference to Figures 1Ato 1J of the accompanying drawings.