WO2019211699A1

WO2019211699A1 - Float valve comprising a trigger mechanism

Info

Publication number: WO2019211699A1
Application number: PCT/IB2019/053301
Authority: WO
Inventors: Abdul Rasool DEEN MUHAMMAD; Ebrahim FADHL MOHAMMED ALRAEI; Yousuf HASSAN ABDULLA NOOR ALBUREI; Branly ANIS NASSOUR; Adinarayanan VARADARAJAN VARADARAJAN; Muhammad Shafeeque NELLIYOTE
Original assignee: Dubai Electricity & Water Authority
Priority date: 2018-04-30
Filing date: 2019-04-22
Publication date: 2019-11-07

Abstract

A float valve comprises a valve body having an internal bore and which comprises an inlet and an outlet. The inlet and the outlet are arranged so as to be able to be in fluid communication with each other via the internal bore. The valve comprises an elongate arm pivotably mounted to the valve body. The elongate arm comprises a float mounted on the elongate arm and moveable with respect to the valve body. The valve comprises a valve seat, and a piston moveable within the internal bore between an open position in which fluid can flow between the inlet and the outlet, and a closed position in which the piston can cooperate with the valve seat so as to prevent fluid flow between the inlet and the outlet. The valve further comprises a first resilient biasing element arranged so as to be able to urge the piston towards the valve seat, and a trigger mechanism arranged to be able to hold the piston in the open position. The trigger mechanism is arranged to be able to cooperate with the elongate arm so that, at a first threshold position of the float with respect to the valve body, the piston can be released from the open position and be urged by the first resilient biasing element to the closed position. The valve comprises a reset mechanism arranged to be able to cooperate with the elongate arm so as to be able to move the piston from the closed position to the open position where it is held by the trigger mechanism when the float moves from the first threshold position to a second threshold position with respect to the valve body.

Description

Specification

The present application relates to a float valve.

Float valves, which may also sometimes be referred to as ballcocks, are often used to fill cisterns, tanks, or containers with liquids such as water, while reducing the likelihood of overflow. Typically, a float may be coupled to a valve so that the flow of liquid through the valve depends on the liquid level. Once the liquid reaches a predetermined level, the valve shuts off. As the liquid level falls, the float falls with it and so the valve becomes open thus allowing liquid to flow through the valve. Common float valves comprise a float mounted at an end of an arm which is pivotably connected to a valve. The arm may be linked to the valve so as to open and close the valve depending on the position of the arm and hence liquid level.

However, when the liquid level is at, or very close to, the predetermined level where the valve should be shut off (e.g. a “full” level), the valve may not close completely and small movements of the arm due to small changes in liquid level may still allow liquid to flow through the valve. This may sometimes be referred to as a“low flow” situation. Therefore, the valve may be considered to leak or trickle liquid through the valve (trickle flow), even if it is supposed to be closed. Additionally, since the rate of flow through the valve typically depends on the liquid level and is generally slower near the“full” level, it may take a long time for the liquid level to be such that the valve is closed. Additionally, the buoyant force provided by the float near the full level may not be sufficient to create a full seal, especially if there is a build-up of debris, dirt, or limescale for example over time which may increase friction between the arm and valve, or affect a sealing surface of the valve.

In countries where water management is especially important, such as those in the Middle East or desert areas, this may be an issue because water may be unnecessarily wasted. Additionally, it may hinder accurate monitoring of water consumption because many flow meters are not particularly accurate in conditions where flow rate is low (low flow). Some previous float valves use an electromechanical arrangement to electrically measure a float position and thus control whether to open or close the valve electomechanically. However, such float valves can be costly and complex to manufacture, as well as requiring an electrical supply in order to operate. Other float valves use a membrane in the valve to control the flow, but may be susceptible to blocking of an orifice in the valve which affects whether the membrane moves, thus leading to less reliable operation over time.

Examples of the present disclosure seek to address or at least alleviate the above problems.

In a first aspect, there is provided a float valve comprising: a valve body having an internal bore and comprising an inlet and an outlet, the inlet and the outlet being arranged so as to be able to be in fluid communication with each other via the internal bore; an elongate arm pivotably mounted to the valve body, the elongate arm comprising a float mounted on the elongate arm and moveable with respect to the valve body; a valve seat; a piston moveable within the internal bore between an open position in which fluid can flow between the inlet and the outlet, and a closed position in which the piston can cooperate with the valve seat so as to prevent fluid flow between the inlet and the outlet; a first resilient biasing element arranged so as to be able to urge the piston towards the valve seat; a trigger mechanism arranged to be able to hold the piston in the open position and arranged to be able to cooperate with the elongate arm so that, at a first threshold position of the float with respect to the valve body, the piston can be released from the open position and be urged by the first resilient biasing element to the closed position; and a reset mechanism arranged to be able to cooperate with the elongate arm so as to be able to move the piston from the closed position to the open position where it is held by the trigger mechanism when the float moves from the first threshold position to a second threshold position with respect to the valve body.

For example, the valve could be mounted to a tank, cistern, or container so that float can float on a liquid in the tank and so that liquid can flow into the tank via the valve. For example, the first threshold position can correspond to a desired liquid fill level of the tank, e.g. a desired water level where the tank is full. Below this level, and when the piston is in the open position, liquid can flow through the valve and thus fill the tank at a relatively high rate, for example. For example, as the liquid level rises to the first threshold position, the trigger mechanism can cause the piston to be released so as to move from the open position to the closed position, thus preventing fluid flow between the inlet and the outlet, and so the tank no longer fills up. For example, once the valve is triggered so that the piston moves from the open position to the closed position, the piston can remain biased or urged towards the valve seat by the first resilient biasing element until reset to the open position by the reset mechanism when the float reaches the second threshold position from the first threshold position. In other words, for example, the valve of the present disclosure may be considered to have bistable operation.

Therefore, for example, the piston should remain in the closed position even if there are changes in liquid level and hence float position between the first threshold position and the second threshold position. Fluid flow may, for example, thus be prevented even if the float subsequently moves with respect to the valve body, for example due to small changes in liquid level near the full level. However, if, for example, the float moves past the second threshold position, for example due to a drop in liquid level larger than a distance between the first threshold position and the second threshold position, the piston can be caused to move to the open position by the reset mechanism and be held there by the trigger mechanism until triggered again. Therefore, for example, the valve of the present disclosure may help reduce a problem of low flow because a situation in which the valve may only be partially open such as to allow a trickle flow or low flow, may be reduced. Furthermore, for example, the valve may be less likely to block and may be cheaper and simpler to manufacture.

Other aspects and features are defined in the appended claims.

Examples of the disclosure will now be described by way of example only with reference to the accompanying drawings, in which like references refer to like parts, and in which:

Figure 1 is a schematic representation of a float valve in an open position according to a first example of the disclosure;

Figure 2 is a schematic representation of the float valve according to the first example in a closed position;

Figure 3 is a schematic representation of the float valve according to the first example in a reset position;

Figure 4 is a schematic representation of a float valve according to a second example of the disclosure;

Figure 5 is a schematic representation of a portion of a reset mechanism according to the second example of the disclosure;

Figure 6 is a schematic representation of the float valve according to the second example in the open position;

Figure 7 is a schematic representation of the float valve according to the second example in the closed position;

Figure 8 is a schematic representation of the float valve according to the second example in the closed position illustrating operation of a reset mechanism;

Figure 9 is a schematic representation of the float valve according to the second example illustrating further operation of the reset mechanism ; and

Figure 10 is a schematic representation of the float valve according to the second example

A float valve is disclosed. In the following description, a number of specific details are presented in order to provide a thorough understanding of the examples of the disclosure. It will be apparent however to a person skilled in the art that these specific details need not be employed in order to practise the examples of the disclosure. Conversely, specific details known to the person skilled in the art are omitted for the purposes of clarity in presenting the examples.

Figures 1 to 3 relate to a float valve according to a first example of the present disclosure. In particular, Figure 1 is a schematic representation of a float valve 1 in an open position according to a first example of the disclosure. Flerein, the fluid is described as being water. Flowever, it will be appreciated that the float valve of the present disclosure may be used with any suitable fluid and need not be water, but could be any liquid. The float valve 1 comprises a valve body 10 having an internal bore 12. The valve body 10 comprises an inlet 14 and an outlet 16. The inlet 14 and the outlet 16 are arranged to be able to be in fluid communication with each other via the internal bore 12. In other words, for example, a fluid such as water may be able to flow between the inlet 14 and the outlet 16. In examples, the inlet 14 com prises a connection for coupling it to an inlet pipe for supplying liquid, such as a fill pipe of a water cistern. In examples, the float valve 1 may be mounted in or to a cistern or tank so as to allow the cistern or tank to be filled with liquid up to a predetermined liquid level. Whilst the terms“inlet” and“outlet” have been used for the sake of ease of understanding, it will be appreciated that fluid could flow from the inlet 14 to the outlet 16 or from the outlet 16 to the inlet 14, in other words, between the inlet 14 and the outlet 16, for example. That is, for example, the inlet 14 could be an outlet, and the outlet 16 could be an inlet.

The float valve 1 comprises an elongate arm 18 pivotably mounted to the valve body 10. The elongate arm 18 comprises a float 20 mounted on the elongate arm 18 and moveable with respect to the valve body 10. For example, the float valve 1 may be mounted to a tank so that the float 20 may float on the surface of a liquid within the tank. As the liquid level within the tank changes, the float 20 may thus, for example, move up or down depending on the liquid level in the tank. The outlet 16 may be positioned so that liquid flowing through the valve 1 can flow into the tank.

In examples, the arm 18 comprises a first end 22 and a second end 24 and the arm extends substantially between the first end 22 and the second end 24. In examples, the first end 22 may be mounted to the valve body 10 so that the arm 18 can pivot about the first end 22. The float 20 may be mounted on the arm 18 at the second end 24. In examples, the float 20 is an air tight hollow sphere, although it will be appreciated that any shape could be used as appropriate and that any material or configuration of float suitable to be buoyant on liquid such as expanded polyurethane foam or other solid or colloidal buoyant material, plastics material, or other hollow air tight arrangement or container could be used.

The valve 1 comprises a valve seat 26 and a piston 28 moveable within the internal bore 12 between an open position in which fluid can flow between the inlet 14 and the outlet 16, and a closed position in which the piston 28 can cooperate with the valve seat 26 so as to prevent fluid flow between the inlet 14 and the outlet 16. In examples, the valve seat 26 is located between the inlet 14 and the outlet 16. In examples, the piston 28 and internal bore 12 are configured so that when mounted, the piston 28 can move horizontally. However, it will be appreciated that the valve 1 could be mounted in any appropriate orientation, for example such that the piston 28 could move vertically.

Referring to Figure 1 for example, the piston 28 is shown in the open position. Referring to Figure 2 for example, the piston is shown in the closed position. In examples, the piston 28 is substantially cylindrical and comprises a conical portion 30 (valve seat engaging portion) located towards the valve seat 26. In examples, the valve seat 26 comprises an o-ring 32 arranged to be able to cooperate with the conical portion 30 to form a seal when the piston 28 is in the closed position, for example by the piston 28 being pressed against the o-ring 32. The conical portion 30 may help the piston 28 to locate centrally with the o-ring so as to help improve the seal. However, it will be appreciated that the portion of the piston 28 that can engage with the valve seat could have any suitable shape such as planar, hemispherical, frustoconical, frusto- hemispherical, or other shape or cross-section. Furthermore, the use of the piston 28 and valve seat 26 of the examples of the disclosure means that other seals between the piston and the valve body 10 may not be needed and so the piston 28 may slide freely within the internal bore 12, thus helping to simplify manufacture, for example. It will also be appreciated that other suitable arrangements for preventing fluid flow between the inlet 14 and the outlet 16 when the piston 28 is in the closed position could be used.

The valve 1 comprises a first resilient biasing element 34 arranged so as to be able to urge the piston 28 towards the valve seat 26. In examples, the first resilient biasing element 34 is a helical spring, although it will be appreciated that other spring arrangements, elastomeric elements or other suitable magnetic arrangements could be used to bias the piston 28 towards the valve seat 26. In examples, the first resilient biasing element is a compression spring, although a tension spring or torsion spring could be used with changes to the configuration of the piston 28 and valve body 10 as appropriate. In examples, the valve body 10 comprises an internal wall 36 within the internal bore 12 and the piston 28 comprises a biasing element engaging portion 38. In examples, the first resilient biasing element 34 is positioned to be able to act between the internal wall 36 and the biasing element engaging portion 38 so as to be able to urge or bias the piston 28 towards the valve seat 26. In examples, the first resilient biasing member 34 is positioned between the internal wall 36 and the biasing element engaging portion so that movement of the piston 28 away from the valve seat 26 can cause the first resilient biasing member 34 to be compressed.

The valve 1 comprises a trigger mechanism arranged to be able to hold the piston 28 in the open position. The trigger mechanism is arranged to be able to cooperate with the elongate arm 18 so that, at a first threshold position of the float 20 with respect to the valve body 10, the piston 28 can be released from the open position and be urged by the first resilient biasing element 34 to the closed position. The valve also comprises a reset mechanism arranged to be able to cooperate with the elongate arm 18 so as to be able to move the piston 28 from the closed position to the open position where it is held by the trigger mechanism when the float 20 moves from the first threshold position to a second threshold position with respect to the valve body. The trigger mechanism and reset mechanism will be described in more detail later below.

Referring to Figure 2 for example, the float 20 is shown at the first threshold position 40 with respect to a reference position 42. In examples, the reference position 42 corresponds to an edge of the valve body 10, such as a top edge as schematically illustrated in Figures 2 and 3. Flowever, any suitable reference position could be used, such as a point on the valve body. In examples, a first threshold distance 44 is a distance between the first threshold position 40 and the reference position 42.

Referring to Figure 3 for example, the float 20 is shown at the second threshold position 46 with respect to the reference position 42. In examples, a second threshold distance 48 is a distance between the second threshold position 46 and the reference position 42. In examples, the first threshold position and the second threshold position are defined with respect to a centre of the float 20, although it will be appreciated that any suitable part of the float 20 (or arm 18) could be used. Additionally, as mentioned above, the reference position 42 could be any suitable point or line defined with respect to the valve body.

In examples, the second threshold position is lower than the first threshold position, when for example, the valve 1 is operably mounted within a tank or cistern. More generally, in examples, the first threshold position 40 is closer to the reference position 42 than the second threshold position 46. In other words, in examples, the first threshold distance is smaller than the second threshold distance.

Accordingly, the float valve of examples of the disclosure, can, for example, be thought of as a bistable valve. For example, the valve 1 can be mounted to a tank so that the first threshold position 40 can correspond to a desired liquid fill level of the tank, e.g. a desired full tank level. Below this level, and when the piston 28 is in the open position, liquid can continue to flow through the valve and thus fill the tank, for example. At the first threshold position 40, for example, the trigger mechanism can cause the piston 28 to be released so as to move from the open position to the closed position, thus restricting and preventing fluid flow between the inlet 14 and the outlet 16. For example, once the valve 1 is triggered so that the piston 28 moves from the open position to the closed position, the piston 28 can remain biased or urged towards the valve seat 26 by the first resilient biasing element 34 until reset to the open position by the reset mechanism when the float reaches the second threshold position from the first threshold position. It will be appreciated that, in examples, the float 20 can move within positions between the first threshold position 40 and the second threshold position 46 without causing the piston 28 to move from the closed position to the open position.

Therefore, for example, the piston 28 should remain in the closed position even if there are changes in liquid level and hence float position between the first threshold position and the second threshold position. Fluid flow may, for example, thus be prevented even if the float 20 subsequently moves with respect to the valve body 10, for example due to small changes in liquid level. Flowever, if, for example, the float 20 moves past the second threshold position, for example due to a drop in liquid level larger than a distance between the first threshold position and the second threshold position, the piston 28 can be caused to move to the open position and be held there by the trigger mechanism until triggered again. Therefore, for example, the valve 1 of the present disclosure may help reduce a problem of low flow because a situation in which the valve may only be partially open such as to allow a trickle flow, may be reduced.

Further details of the trigger mechanism will now be described with reference to Figure 1 . In examples, the trigger mechanism comprises a trigger 50 mounted to the valve body 10 so as to be able to move with respect to the valve body 10. In examples, the trigger 50 comprises a first end 52 and a second end 54, and is pivotably mounted to the valve body 10 between the first end 52 and the second end 54, for example at a trigger pivot point 56. In examples, a notch 58 is formed in the piston 28 for engaging with the trigger 50 to hold the piston 28 in the open position. In examples, the trigger mechanism comprises a second resilient biasing element 60 arranged to bias the trigger 50 into the notch 58. The trigger 50 may be arranged to cooperate with the arm 18 so that, when the trigger 50 is engaged with the notch 58 and the float 20 reaches the first threshold position 40, the trigger 50 can be caused to disengage the notch 58 to release the piston 28. For example, the arm 18 can be arranged to contact the trigger 50 so as to cause the trigger 50 to be pushed out of the notch 58.

In examples, the first end 52 comprises a protrusion 62 arranged to be able to engage with the notch 58. In examples, the second resilient biasing element 60 is positioned so as to bias the protrusion 62 into the notch 58. To achieve this, the valve body 10 may comprise a biasing element support arm 64 and the second resilient biasing element 60 may be positioned so as to act between the support arm 64 and the first end 52 of the trigger 50 so as to bias the protrusion 62 into the notch 58. In examples, the second resilient biasing element 60 is a helical spring, although other suitable springs such as a single leaf spring, torsion spring or plate spring could be used. Additionally, it will be appreciated that the second resilient biasing element 60 could be formed from elastomeric material. The second resilient biasing element 60 may be arranged to be in tension or compression so as to urge or bias the protrusion 62 into the notch 58. Additionally, it will be appreciated that the second resilient biasing element 60 could be part of the trigger 50 or integrally formed with the trigger 50.

In examples, the second end 54 is arranged to be contactable by the arm so as to be able to cause the protrusion 62 to move out of the notch 58. However, it will be appreciated that other configurations and arrangements are possible. In examples, the elongate arm 18 comprises a first finger 66 which extends from the elongate arm 18 and which is positioned to be able to engage the trigger 50 to cause the piston 28 to be released from the open position to the closed position. Additionally, while in examples the trigger 50 can be pivoted so as to release the piston 28, it will be appreciated that the trigger 50 could, for example, be arranged so as to be able to slide or flex to achieve the same functionality of releasing the piston 28 when the float is at the first threshold position, for example.

The operation of the trigger mechanism will now be described with reference to Figures 1 and 2. In Figure 1 , for example, the float 20 is positioned further away from the reference position 42 than the first threshold position. For example, a liquid level in the tank is below the“full” level and so the tank can be filling with liquid supplied through the valve 1 . As the liquid level rises, the float 20 will move closer to the reference position 42. As the float 20 moves towards the reference position 42, the arm 18 pivots about the first end 22 of the arm 18 and so the first finger 66 moves towards the second end 54 of the trigger 50 until it makes contact with the trigger 50. Movement of the first finger 66 towards the valve body can cause the first finger 66 to touch the second end 54 of the trigger 50 and cause it to rotate about the pivot point 56 against the bias provided by the second resilient biasing element 60. The protrusion

62 can thus be caused to move away from the notch 58 until it disengages from the notch 58 when the float 20 is at the first threshold position 40, thus allowing the piston 28 to move from the open position to the closed position as urged by the first resilient biasing element 34, for example as shown in Figure 2.

The reset mechanism of the first example will now be described in more detail with reference to Figures 1 to 3. In examples, the reset mechanism comprises a load coupled to the piston 28 and able to move under the force of gravity to cause the piston 28 to be moved away from the valve seat 26. In examples, the load is coupled to the piston 28 by an elongate connecting element 68, such as a rope, and arranged so that downward movement of the load under gravity can cause the piston 28 to move away from the valve seat 26. In examples, the elongate connecting element 68 is a string, although it could be a cord, rope, a chain or other suitable element for coupling the load to the piston 28. In the first example described with respect to Figures 1 to 3, the arm 18 is configured to be able to act as at least part of the load. In these examples, the reset mechanism comprises an extendible resilient element 70, such as an extension spring, arranged to act between the arm 18 and the piston 28, for example via the elongate connecting element 68.

In examples, the arm 18 comprises a hook 72 arranged to engage with a first end 74 of the extendible resilient element 70. In examples, the valve body 10 comprises a pulley 76 to be able to freely rotate within the valve body 10. In the example of Figures 1 to 3, the elongate connecting element 68 is connected to a second end 78 of the extendible resilient element 70, and connected to the piston 28 at the biasing element engaging potion 38. The elongate connecting element 68 passes over the pulley 76 so that vertical movement of the hook 72 can be translated to horizontal movement of the piston 28 by causing the first resilient biasing element 34 to be compressed. Flowever, in other examples where the piston 28 may be configured to move vertically, the pulley 76 could be omitted. In examples, the o-ring 32 is compressible by the conical portion 30 of the piston 28 so as to form a seal between the valve seat 26 and the piston 28. Therefore, for example, fluid flow from the inlet 14 to the outlet 16 may be prevented when the conical portion 30 is within a sealing threshold distance of the valve seat 26. Accordingly, in examples, the piston 28 is in the closed position when the conical portion 30 is within the sealing threshold distance from the valve seat 26.

In examples, a spring constant of the extendible resilient element 70 is less than a spring constant of the first resilient biasing element 34. Therefore, for example, when the float 20 is moved away from the valve body 10, for example because of a drop in liquid level, the extendible resilient element 70 will extend in preference to compressing the first resilient biasing element 34. Accordingly, in examples, the piston 28 can remain in the closed position while the float is less than the second threshold distance from the valve body 10 (such as from the reference position 42). This is because downward force provided by the load (for example the weight of the arm 18) acting under the force of gravity may cause the extendible resilient element 70 to extend more than the compression of the first resilient biasing element 34.

However, for example, once the float 20 is at or further away from the valve body 10 than the second threshold position (e.g. as shown in Figure 3), the compression of the first resilient biasing element 34 may be such that the valve can be in the open position so that fluid can flow between the inlet 14 and the outlet 16. In examples, movement of the float 20 away from the valve body 10 can cause the piston 28 to be moved away from the valve seat 26 as drawn by the elongate connecting element 68 from the closed position to the open position where the trigger 50 can engage the notch 58 to hold the piston 28 in the open position. Therefore, for example, the piston 28 of the valve 1 can remain in the closed position over a range of positions of the arm 18 thus helping to reduce a problem of low or trickle flow.

In examples, the extendible resilient element 70 comprises a restricting element arranged to restrict elongation of the extendible resilient element 70 further than a restriction threshold distance. For example, where the extendible resilient element 70 is a helical spring, the restricting element could be a bar placed within the helical spring with plates either end of the spring so that contact of the spring with the plates restricts or prevents further extension. In these examples, when the extendible resilient element 70 extends to the restriction threshold distance, force from the load may be transferred directly to the piston 28 to compress the biasing element 34 and help reset the piston 28 to the open position where it is held by the trigger mechanism.

An alternative reset mechanism of a second example of a float valve 100 according to examples of the disclosure will now be described with reference to Figures 4 to 10. The float valve 100 is substantially the same as the float valve 1 described above with respect to Figures 1 to 3 except that the reset mechanism and the arm are different in the second example. In Figures 6 to 10 some reference numerals have been omitted for clarity in understanding the drawings, but the skilled person will appreciate the features in common between the second example and the first example at least on inspection of Figure 4 with respect to Figures 1 to 3, as well as the above description.

In the second example, the float valve 100 comprises a load 102 able to move with respect to the valve body 10 and coupled to the piston 28 by the elongate connecting element 68 in a similar manner to the first example. Flowever, the extendible resilient element 70 may be omitted. In the second example, the float valve comprises a latch mechanism arranged to hold the load 102 in a latched position corresponding to the closed position of the piston 28, and to release the load 102 to be able to move under the force of gravity when the float 20 reaches the second threshold position from the first threshold position.

The float valve 100 of the second example comprises an arm 1 18. In examples, the arm 1 18 comprises a first end 122 and a second end 124 and the arm 1 18 extends substantially between the first end 122 and the second end 124 in a similar manner to the first example. In examples, the first end 122 may be mounted to the valve body 10 so that the arm 1 18 can pivot about the first end 122. The float 20 may be mounted on the arm 1 18 at the second end 124.

In examples, the arm 1 18 is arranged so as to be able to lift the load 102 into the latched position. To achieve this, in examples, the arm 1 18 comprises a second finger 104 extending from the arm 1 18 and positioned so as to be able to contact the load 102 to lift it into the latched position. Referring to Figures 4 and 5, in examples, the latching mechanism comprises a latch 200 arranged to support the load 102 when in the latched position. In examples, the arm 1 18 comprises a third finger 106 extending from the arm 1 18 and configured to hold the latch 200 in the latched position when the float 20 is between the first threshold position 40 and the second threshold position 46 and when the piston 28 is in the closed position.

In examples, the latch 200 comprises a lip 202 arranged to be able to support or hold the load 102 when the latch 200 is in the latched position. In other words, for example, the latched position corresponds to a position of the latch 200 where the lip 202 can support the load 102 so as to restrict downward motion of the load 102, for example by the load 102 sitting on the lip 202.

In examples, the latch 200 is mounted to the valve body 10 at a latch mount position 203 so that the lip 202 can move with respect to the valve body 10, for example towards and away from the load 102. In examples, the latch 200 comprises a finger engaging surface 204 arranged to be contactable by the third finger 106. The latch 200 is arranged so that upward motion of the third finger 106 can cause the lip 202 to move towards the load 102, for example by pivoting about the latch mount position 203. In examples, the latch 200 is resiliently biased away from the latched position. Therefore, for example, as the float 20 is moved away from the valve body 10, the latch 200 can be caused to move away from the latched position so as to allow the load 102 to move downwards under gravity, thus moving the piston 28 away from the valve seat 26 and into the open position where it is held by the trigger 50.

The operation of the reset mechanism of the second example will now be described with reference to Figures 4, and 6 to 10.

Referring to Figure 4 for example, the piston 28 is in the open position and held by the trigger 50. In the example of Figure 4, a liquid level is rising so that the float 20 is moving upwards. The second finger 104 makes contact with the load 102 and moves it upwards. In this position, for example, the third finger 106 starts to make contact with the finger engaging surface 204 of the latch 200, pushing it towards the load 102.

Referring to Figure 6, for example, the liquid level can be considered to be higher than in the example of Figure 4, and is rising, and so the float 20 is moving towards the valve body 10. The second finger 104 is in contact with the load 102 and lifting it upwards. In examples, the second finger 104 is arranged so as to be able to be in contact with the load 102 when the piston 28 is held in the open position by the trigger 50 and when the float 20 is between the second threshold position 46 and the first threshold position 40. In the examples shown in Figure 6, the third finger 106 is in contact with the finger engaging surface 204 of the latch 200 and urging (pushing) the lip 202 towards the load. In the example of Figure 6, the piston 28 is held in the open position by the trigger 50 because the float 20 is further away from the valve body than the first threshold position 40.

Referring to Figure 7, for example, the liquid level can be considered to be higher than the example in Figure 6. The float 20 is at the first threshold position 40 and so the first finger 66 is engaged with the trigger 50 so that the piston 28 is released from the open position where it is held by the trigger 50 to the closed position where it is urged towards the valve seat 26 to prevent fluid flow from the inlet 14 to the outlet 16. The load 102 is shown lifted above the lip 202 of the latch 200 by the second finger 104. In examples, this may also create some slack in the elongate connecting element 68 so that the piston 28 can move towards the valve seat 26 when released by the trigger. The third finger 106 is positioned to engage the finger engaging surface 204 such that the lip 202 is positioned below the load 102. In examples, further upward movement of the float 20 is restricted by contact of the first finger 66 with the trigger 50.

Referring to Figure 8, for example, the piston 28 is in the closed position so as to prevent or restrict fluid flow between the inlet 14 and the outlet 16. The float 20 is positioned between the first threshold position 40 and the second threshold position 46. In the example of Figure 8, the liquid level can be considered to be lower than in the example of Figure 7 and falling. In the example shown in Figure 8, the second finger 104 is not in contact with the load 102. Flowever, the load 102 is supported (held) on the lip 202 of the latch 200 because the latch 200 is urged towards the load 102 by the third finger 106 being in contact with the finger engaging surface 204 of the latch 200. Therefore, for example, the piston 28 is held in the closed position when the float 20 is between the first threshold position 40 and the second threshold position 46 because the load 102 is restricted from moving downwards by the lip 202 of the latch 200.

Referring to Figure 9, for example, the float 20 is at the second threshold position 46 and below the first threshold position 40. In examples, when the float 20 is at the second threshold position 46, the third finger 106 and the finger engagin g surface are positioned such that the lip 204 can move away from the load 102 from the latched position to the unlatched position because the latch 200 is biased to be urged away from the load 102 for example, thus allowing the load 102 to move downwards. In examples, downward movement of the load 102 from the latched position can cause the piston 28 to be moved away from the valve seat 26 because of the mechanical coupling between the load 102 and the piston 28 via the elongate connecting element 68. In examples, the mass of the load 102 is able to exert a force greater than the biasing force provided by the first resilient means 34 towards the valve seat 26. In other words, for example, downward movement of the load 102 from the latched position can cause the first resilient biasing element 34 to be compressed between the piston 28 and the internal wall 36, and cause the protrusion 62 of the trigger 50 to engage with the notch 58 to hold the piston 28 in the open position. Therefore, for example, the piston 28 can thus be considered to be able to be reset to the open position where fluid can flow between the inlet 14 and the outlet 16 via the internal bore 12.

Referring to Figure 10, for example, the float 20 is further away from the valve body 10 than the first threshold position 40 and the second threshold position 46. The piston 28 is in the open position to be held by the trigger 50. The second finger 104 is not in contact with the load 102 and the third finger 106 is not in contact with the finger engaging surface 204 of the latch 200. Therefore, for example, movement of the float 20 with respect to the valve body when the float is further away from the valve body than the second threshold position 46 does not affect the trigger mechanism or the reset mechanism in the second example, and so flow rate should be unaffected. For example, a tank or cistern to which the valve 100 is mounted may be filled when the piston 28 is in the open position.

In examples, one or more of the first finger 66, the second finger 104 and the third finger 106 comprises a low friction element so as to reduce friction where the finger is to make contact with another element such as the trigger 50 or latch 200. In some examples, an end of the finger may be coated with a low friction material such as polytetrafluoroethylene (PTFE), although other suitable low friction materials could be used.

The float valve of the examples of the disclosure may, for example, be coupled with a smartwater meter for example to measure flow rate through the valve and thus water consumption. In examples, the valve of examples of the disclosure is configured to be able to cooperate with a smart meter so as to monitor flow and use of liquid by a consumer. Smart meters are typically used to measure water consumption and report water usage to a water provider electronically, for example via a suitable network such as the internet. The valve according to examples of the present disclosure may enable water consumption to be measured more accurately for example, because the likelihood of a low flow situation occurring may be reduced. In some examples, the valve may comprise a flow sensor operable to communicate with a smart meter so as to report flow rate through the valve to a utilities provider. Furthermore, for example, water or liquid wastage may also be reduced because flow may be prevented when the float 20 is between the first threshold position 40 and the second threshold position 46 when the piston 28 is in the closed position (e.g. pressed to the valve seat 26 by the first resilient biasing means 34). Additionally, it will be appreciated that the examples and features of the first example and the second example could be combined as appropriate.

Although a variety of examples have been described herein, these are provided by way of example only and many variations and modifications on such examples will be apparent to the skilled person and fall within the spirit and scope of the present invention, which is defined by the appended claims and their equivalents.

Claims

1 . A float valve comprising:

a valve body having an internal bore and comprising an inlet and an outlet, the inlet and the outlet being arranged so as to be able to be in fluid communication with each other via the internal bore;

an elongate arm pivotably mounted to the valve body, the elongate arm comprising a float mounted on the elongate arm and moveable with respect to the valve body;

a valve seat;

a piston moveable within the internal bore between an open position in which fluid can flow between the inlet and the outlet, and a closed position in which the piston can cooperate with the valve seat so as to prevent fluid flow between the inlet and the outlet;

a first resilient biasing element arranged so as to be able to urge the piston towards the valve seat;

a trigger mechanism arranged to be able to hold the piston in the open position and arranged to be able to cooperate with the elongate arm so that, at a first threshold position of the float with respect to the valve body, the piston can be released from the open position and be urged by the first resilient biasing element to the closed position ; and

a reset mechanism arranged to be able to cooperate with the elongate arm so as to be able to move the piston from the closed position to the open position where it is held by the trigger mechanism when the float moves from the first threshold position to a second threshold position with respect to the valve body.

2. A valve according to claim 1 , in which:

the trigger mechanism comprises:

a trigger mounted to the valve body so as to be able to move with respect to the valve body;

a notch formed in the piston for engaging with the trigger to hold the piston in the open position; and

a second resilient biasing element arranged to bias the trigger into the notch; and

the trigger is arranged to cooperate with the arm so that, when the trigger is engaged with the notch and the float reaches the first threshold position, the trigger can be caused to disengage the notch to release the piston.

3. A valve according to claim 2, in which the arm comprises a first finger which extends from the arm and which is positioned to be able to engage the trigger to cause the piston to be released from the open position to the closed position.

4. A valve according to claim 2 or claim 3, in which:

the trigger comprises a first end and a second end, and is pivotably mounted to the valve body between the first end and the second end;

the first end comprises a protrusion arranged to be able to engage with the notch, the second resilient biasing element being positioned so as to bias the protrusion into the notch; and

the second end is arranged to be contactable by the arm so as to cause the protrusion to move out of the notch.

5. A valve according to any preceding claim, in which the reset mechanism comprises a load coupled to the piston and able to move under the force of gravity to cause the piston to be moved away from the valve seat.

6. A valve according to claim 5, in which the load is coupled to the piston by an elongate connecting element and arranged so that downward movement of the load under gravity can cause the piston to move away from the valve seat.

7. A valve according to claim 5 or claim 6, in which the arm is configured to be able to act as at least part of the load.

8. A valve according to claim 7, comprising an extendible resilient element arranged to act between the arm and the piston.

9. A valve according to claim 8, in which a spring constant of the extendible resilient element is less than a spring constant of the first resilient biasing element.

10. A valve according to claim 5 or claim 6, comprising a latch mechanism arranged to hold the load in a latched position corresponding to the closed position of the piston, and to release the load to be able to move under the force of gravity when the float reaches the second threshold position from the first threshold position.

1 1 . A valve according to claim 10, in which the arm is arranged so as to be able to lift the load into the latched position.

12. A valve according to claim 1 1 , in which the arm comprises a second finger extending from the arm and positioned so as to be able to contact the load to lift it into the latched position.

13. A valve according to any of claims 10 to 12, in which:

the latching mechanism comprises a latch arranged to support the load when in the latched position; and

the arm comprises a third finger extending from the arm and configured to hold the latch in the latched position when the float is between the first threshold position and the second threshold position.

14. A valve according to claim 13, in which the latch is resiliently biased away from the latched position.

15. A valve according to any preceding claim, in which the valve is configured to be able to cooperate with a smart meter so as to monitor flow and use of liquid by a consumer.