GB2477803A

GB2477803A - Float valve

Info

Publication number: GB2477803A
Application number: GB1002613A
Authority: GB
Inventors: Peter Martin Broatch
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-02-16
Filing date: 2010-02-16
Publication date: 2011-08-17
Also published as: GB201002613D0

Abstract

A float valve assembly 50 has a first member 52 having an opening 58 and arranged to be fed by a water supply, and a movable member 54. The member 54 is movable between a closed position in which it blocks the opening 58 and closes off the water supply and an open position in which water can flow from the opening 58 to a space 86 between the first 52 and second 54 members and thence to an outlet 30. An operating member is connected to a float 78 and coupled to the movable member 54 so that elevation of the float 78 causes the movable member 54 to move from the open to the closed position. A restriction 53 is disposed downstream of the opening 58 for restricting the flow of water from the space 86 to the outlet 30 so that backpressure in the space 30 acts to urge the movable member 54 towards the open position, to provide a fast turn-off during the final phase of movement to the closed position. The degree of restriction when the movable member 54 is in the open position is less than it is part way between the open and closed positions, so as not to restrict the water flow unnecessarily when the valve is open.

Description

TITLE

Float valves

DESCRIPTION

This invention relates to float valve assemblies.

More particularly, this invention relates to a float valve assembly for connection to a water supply, comprising: a first member having an opening arranged to be fed by the water supply; a second member, one of the members being movable between (i) a closed position in which the second member blocks the opening and closes off the water supply and (ii) an open position in which, in use, water can flow from the opening to a space between the first and second members and thence to an outlet of the float valve assembly; and an operating member connected to, or for connection to, a float and coupled to the movable one of the members so that, in an in use orientation of the float valve assembly, rising of the float from a lower position to an upper position causes the movable member to move from the open position to the closed position.

Such float valve assemblies are extremely well known and find application in, for example, toilet cisterns, domestic water tanks and animal watering troughs. In operation, as the water level in the cistern, tank or trough rises, the float is supported by the water and rises so that the water supply is shut off when the water level reaches a particular level. The float valve assembly enables the cistern to be automatically refilled after the toilet has been flushed and the water level in the tank or trough to be kept topped-up automatically.

A known problem with the conventional float valve assemblies is that the final phase of movement of the movable member to the closed position can take a considerable time, during which time the water flow rate is restricted by the second member and the opening approaching one another, and whistling, gurgling and other annoying noises and wear can result.

Patent document GB2383396A discloses a way of overcoming this problem. A restrictor is disposed downstream of the opening for restricting the flow of water from said space to the outlet so that a backpressure can be produced in said space acting to urge the movable member towards the open position. As the first and second members start to approach each other, the backpressure causes the float to be submerged deeper than normal in the water, so that the water flow rate is greater than normal. However, when the first and second members come closer to each other, the restriction of the opening caused by the second member causes the flow rate to reduce, which in turn reduces the backpressure so that the float is no longer submerged deeper than normal in the water, and the final phase of movement of the movable member to the closed position is accelerated. The valve therefore spends less time when it is almost, but not quite, shut. Indeed, with appropriate choice of dimensions, the final phase of the closing of the valve is a snap action.

In the valve of GB2383396A, the restrictor is provided by a pressure relief valve movable against the action of a spring from a minimum opening when the backpressure is less than or equal to a lower threshold to a maximum opening when the backpressure is greater than or equal to a higher threshold. This feature is provided so that, when the float valve assembly is supplied with water at high pressure, the backpressure is not so large, when the float valve assembly is open, that it prevents the movable member moving to its closed position. At high supply pressures, the relief valve moves to its maximum opening when the movable member is in its open position and then moves to its minimum opening as the flow rate reduces. However, at low supply pressures, the relief valve stays at its minimum opening whatever the position of the movable member, and this produces the disadvantage that the restrictor unnecessarily restricts the flow, particularly when the movable member is in its open position.

An aim of the present invention, or at least of specific embodiments of it, is to provide the accelerated final phase of movement of the movable member to its closed position, whilst reducing the degree of unnecessary restriction of the water flow and to do so in a simple manner.

The float valve assembly of the present invention is characterised in that the restrictor is coupled to, or provided at least in part by, the movable member such that the degree of restriction when the movable member is in the open position is less than it is part way between the open and closed positions.

The float valve assembly of the invention therefore provides the advantage of GB2383396A of having a fast close-off speed in the final phase of closing of the valve, but with less restriction on the flow rate when the valve is open.

In a preferred embodiment of the invention, one of the members has a recess facing the other member, and the other member has a projecting portion which is disposed in the recess at least when the movable member is at and adjacent its closed position. The restrictor can therefore be provided by a gap between the overlapping sides of the recess and projecting portion of the other member and may provide a greater degree of restriction the more the closer the movable member is to its closed position. The projecting portion is preferably not disposed in the recess when the movable member is in the open position, so that no substantial restriction is provided in this position. This also has the advantage that if any debris should collect in said space when movable member is at or near its closed position, the debris can be washed out when the movable member subsequently moves to its open position.

The second member preferably has a seal for engaging the first member to block the opening when the movable member is in the closed position. In this case, the recessed member is preferably provided by said second member, and the seal is provided at the base of the recess.

The float valve assembly preferably further includes a pressure relief valve which is operable to bypass the restrictor at high values of the backpressure. In this case, the second member may have a body to which the seal is mounted, with the pressure relief valve being provided by the seal being movable relative to the body in a direction away from the first member against the action of a spring to open a passageway past the seal from said space to the outlet. In an alternative embodiment, the pressure relief valve is provided on the first member and communicates with said space by at least one passageway extending through the first member.

Specific embodiments of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: Figure 1 is an under plan view of a body of a conventional float valve assembly; Figure 2 is a sectional side view of the float valve body; Figure 3 is a partial side view of a conventional ball arm; Figure 4 is a sectioned side view of a conventional inlet connector for the float valve housing; Figure 5 is a sectioned side view of a nut for the inlet connector; Figure 6 is a sectioned side view of an end cap for the float valve body; Figure 7 is a sectioned side view of a conventional inlet nozzle of the float valve assembly; Figure 8 is a sectioned side view of a conventional valve member of the float valve assembly; Figure 9 is a sectioned under plan view of the valve member of Figure 8; Figure 10 is a sectioned side view of the assembled conventional float valve assembly; Figure 11 is a sectioned side view of an inlet nozzle of a float valve assembly of an embodiment of the invention; Figure 12 is a sectioned side view of a first portion of a valve member of the float valve assembly of the embodiment; Figure 13 is a sectioned side view of a second portion of a valve member of the float valve assembly of the embodiment; Figure 14 is an end view of the portion of Figure 13; Figure 15 is a sectioned under plan view of the portion of Figure 14; Figure 16 is an end view of a seal of the valve member of the embodiment; Figure 17 is a side view of a spring of the embodiment; Figure 18 is a sectioned side view of the valve member of the embodiment; Figure 19 is a sectioned under plan view of the valve member of the embodiment; Figure 20 is a sectioned side view of the assembled float valve assembly of the embodiment; Figure 21 is a schematic side view of the float valve assembly of the embodiment in an open position; Figures 22-24 are schematic diagrams of the float valve assembly showing phases in its closing action when fed with water at low pressure; Figures 25-27 are schematic diagrams of the float valve assembly showing phases in its closing action when fed with water at high pressure; Figures 28-30 are a side view, a sectioned side view and an isometric view, respectively, of a modified nozzle, an 0-ring also being shown in Figure 29; Figure 31 is a sectioned side view of a modified valve member; Figure 32 is a sectioned side view of a float valve assembly employing the modified nozzle and valve member of Figures 28 to 31; Figures 33A&B are sectioned side views of the valve members of another conventional float valve in an open position and a closed position, respectively; Figures 34A&B are sectioned side views of the valve members of one modification of the valve members of Figures 33A & B in an open position and a closed position, respectively; and Figures 35A&B are sectioned side views of the valve members of another modification of the valve members of Figures 33A & B in an open position and a closed position, respectively.

Referring to Figures 1 to 10 of the drawings, a conventional float valve assembly 10 to British Standard BS 1212, Part 1 (1990) has a cast and machined brass body 12 (Figures 1 and 2) having a bore with three sections 14,16,18 of decreasing internal diameter. A moulded plastics inlet nozzle 20 (Figure 7) is fitted to the largest diameter section 14 by an inlet coupling 22 (Figure 4) and nut 24 (Figure 5) and projects into the middle section 16. A valve member 26 (Figures 7 and 8) is slidable in the smallest diameter section 18 and is held captive between the inlet nozzle 20 and an end cap 28 (Figure 6). The underside of the body 12 is formed with an outlet port 30 in the region of the middle section 16. The underside of the body 12 is also formed with an elongate opening 32 in the region of the smallest diameter section 18 bounded by a pair of elongate lugs 34. A float arm 36 is pivotally mounted adjacent one end thereof by a split pin 38 between the lugs 34 and has a cranked end 40 which projects through the opening 32 into engagement with a recess 42 in the valve member 26. A float ball (not shown) is attached to the opposite end of the float arm 36. The end of the valve member 26 facing the inlet nozzle 20 is fitted with a rubber seal 44.

As is well known, in a typical use of the float valve assembly 10 of Figures 1 to 10, the inlet coupling 22 is fitted to a hole in a side wall of a cistern and connected to a supply of water.

Water flows through the inlet coupling 22 and inlet nozzle 20 and exits the float valve assembly through the outlet port 30 to fill the cistern. As the water level in the cistern rises the float ball floats on the water and rotates the float arm 36 anticlockwise as viewed in Figure 10, thus pushing the valve member 26 to the left and moving the seal 44 towards the inlet nozzle 20.

Once the water reaches a particular level, the seal 44 engages the tip of the inlet nozzle 20 and so closes the float valve assembly 10. If the water level subsequently drops, the float valve assembly 10 automatically opens and tops up the cistern to the particular level.

Float valve assemblies of the type described above are very popular, are mass produced and accordingly are inexpensive, typically costing about £3 at trade prices at the time of writing.

A modification of the conventional float valve assembly 10 so as to form an embodiment of the invention will now be described with reference to Figure 11 to 20. The float valve assembly 50 of the embodiment of the invention employs a body 12, inlet connector 22, nut 24, end cap 28, float arm 36, split pin 38 and float ball (not shown) which are identical to the components described above of a conventional float valve assembly 10. However, the inlet nozzle 52 and valve member 54 of the embodiment of the invention differ from the inlet nozzle 20 and valve member 26 described above.

The inlet nozzle 52 (Figure 11) is similar to the inlet nozzle 20 except that the tip 53 of the nozzle 52 has a larger external diameter Dl. Also, the tip 53 of the nozzle 52 is formed with an annular ridge 56 immediately around the opening 58 of the nozzle 52.

The valve member 54 has a first brass body portion 60 (Figure 12) which houses a rubber seal 61 (Figure 16), and a second brass body portion 62 (Figures 13 to 15) which is screw-threadedly connected to the first body portion 60 and which is formed with a crank recess 64 for receiving the cranked end 40 of the float arm 36. The seal 61 is held captive in the valve member 54 between a shoulder 66 in the first body portion 60 and a stainless steel compression spring 68 (Figure 17) which is seated in a spring recess 70 in the second body portion 62. The bottom of the spring recess 70 merges with the crank recess 64 at an opening 72. The end wall of the first body portion 60 has a hole 74 which exposes a centre portion of the seal 61 at the bottom of a recess 75. The hole 74 has an internal diameter D2 which is slightly greater than the external diameter Dl of the tip of the inlet nozzle 52. The seal 61 can therefore be depressed into the valve member 54 against the action of the spring 68. The peripheral edge 76 of the seal 61 is a clearance fit in the first body portion 60 and may be notched (as shown in Figure 16) so that when the seal 61 is depressed into the valve member 54, water can flow through the hole 74, past the peripheral edge 76 of the seal 61, into the spring recess 70, through the hole 72, into the crank recess 64 and then exit from the valve body 12 through the crank opening 32.

The operation of the float valve assembly 50 when fed with water at relatively low pressure will now be described with reference to Figures 21 to 24. The float valve assembly 50 is fitted to a side wall of a cistern (not shown) and has a float ball 78 attached to the distal end of the float arm 36.

Starting with an empty cistern, the float arm 36 will be at the limit of its movement in a clockwise direction and the valve member 54 will be at the limit of its movement to the right in the valve body 12. In this position, the larger diameter (Di) portion of the nozzle 52 is clear of the recess 75 in the end of the valve member 54. As shown by the arrowed line 80 in Figure 21, water will flow out of the opening 58 in the inlet nozzle 52, across the exposed face of the seal 61, through the gap between the tip 53 of the nozzle 52 and the valve member 54, through the outlet port 30 and into the cistern.

As the water level 82 in the cistern rises, the float ball 78 will begin to float on the water and rotate the float arm anticlockwise about the split pin 38. Figure 21 shows the stage where the cranked end 40 of the float arm 36 is about to start to move the valve member 54 to the left. The water level 82 is at a distance Vi below the centre line 84 of the float valve assembly 50, and the float ball 78 is submerged at distance Fl below the water level 82.

As shown in Figure 22, as the water level 82 rises further (V2 is less than Vi), the tip 53 of the nozzle 52 begins to enter the recess 75 in the end of the valve member 54, so that a chamber 86 is formed between the tip 53 of the nozzle 52 and the seal 61. Water can escape from the chamber 86 through the gap 88 around the side of the tip 53 of the nozzle 52 due to the difference between the diameters Di and D2. However, the restriction to water flow caused by the gap 88 causes a backpressure in the chamber 86 which is reacted by the float ball 78 being submerged deeper into the water in the cistern (F2 is greater than Fl). Due to the relatively low pressure of the water supply, the backpressure in the chamber 86 during this phase is insufficient to cause the seal 61 to be depressed into the valve member 54.

As the water level 82 rises further, the degree of restriction increases due to the increased overlap of the recess 75 and the tip 53 of the nozzle 52 but, as shown in Figure 23 (V3 is less than V2), the annular ridge 56 around the opening 58 of the nozzle 52 comes close to the seal 61 and causes a significant restriction to water flow at that point. The backpressure in the chamber 86 therefore reduces. The float ball 78 is therefore not urged so deeply into the water during this phase (F3 is less than F2) and the valve member 54 therefore moves to the left at a quicker rate, so that very soon afterwards the stage shown in Figure 24 is reached (V4 is only slightly less than V3; F4 is less than F3). As shown in Figure 24, the seal 61 has come into contact with the annular ridge 56 around the opening 58 of the nozzle 52 so as to close the float valve assembly 50.

It will therefore be appreciated that, in the early phases of filling of the cistern (Figure 21) when the larger diameter (Dl) portion of the nozzle 52 is clear of the recess 75 in the end of the valve member 54, they do not cause any substantial restriction to the flow of water.

However, in the middle phase of filling the cistern (Figure 22), the backpressure in the chamber 86 causes the float ball 78 to be forced deeper into the water than with the conventional float valve assembly 10. Then, as the cistern approaches being full (Figure 23), the backpressure in the chamber 86 reduces so that the float ball 78 rises quicker than with the conventional float valve assembly 10 and the valve member 54 moves to the left quicker than with the conventional float valve assembly 10 SO as to produce a sharper cut-off of the float valve assembly 50 compared with the conventional float valve assembly 10.

The operation of the float valve assembly 50 when fed with water at relatively high pressure will now be described with reference to Figures 21 and 25 to 27.

During the initial phase of filling of the cistern, the float valve assembly 50 acts similarly to the low pressure scenario described above. However, as shown in Figure 25, once the valve member 54 has started to move to the left and form the leaky chamber 86, the higher backpressure in the chamber 86 is sufficient to cause the seal 61 to move away from the shoulder 66 thus opening up an additional path for the flow of water, as shown by the arrowed line 90, from the chamber 86, past the peripheral edge 76 of the seal 61, into the spring recess 70, through the hole 72, into the crank recess 64 and through the crank opening 32 into the cistern. The action of the seal 61 and spring 68 therefore acts as a pressure relief valve for the backpressure in the chamber 86 during this phase in the closing of the float valve assembly 50.

Nevertheless, the depth of submergence F5 of the float ball 78 during this phase is greater than the depth of submergence F2 during the same phase in the low pressure scenario.

As shown in Figure 26, as the water level 82 rises further (V6 is less than V5), the annular ridge 56 around the opening 58 of the nozzle 52 comes close to the seal 61 and causes a significant restriction to water flow at that point. The backpressure in the chamber 86 therefore reduces, and the seal 61 moves back into contact with the shoulder 66 thus closing off the additional flow path 90 for the water. The float ball 78 is not urged so deeply into the water (F6 is less than F5) and the valve member 54 therefore moves to the left at a quicker rate, so that very soon afterwards the stage shown in Figure 27 is reached (V7 is only slightly less than V6; F7 is less than F6). As shown in Figure 27, the seal 61 has come into contact with the annular ridge 56 around the opening 58 of the nozzle 52 so as to close the float valve assembly 50.

At least in the middle phase of filing the cistern (Figure 25), the backpressure in the chamber 86 again causes the float ball 78 to be forced deeper into the water than with the conventional float valve assembly 10. However, the pressure relief action of the seal 61 and spring 68 prevents the float ball 78 being submerged too deeply into the water. Then, as the cistern approaches being full (Figure 26), the backpressure in the chamber 86 reduces so that the pressure relief action ceases and so that the float ball 78 rises quicker than with the conventional float valve assembly 10 and the valve member 54 moves to the left quicker than with the conventional float valve assembly 10 so as to produce a sharper cut-off of the float valve assembly 50 compared with the conventional float valve assembly 10.

It will be appreciated that many modifications and developments may be made to the embodiment of the invention described above with reference to Figures 1 to 6 and 11 to 27.

For example, if the float valve assembly 50 is to be used only with relatively low pressure water supplies, the pressure relief function of the seal 61 and spring 68 may be omitted. Alternatively, the pressure relief function may be provided by the nozzle rather than by the valve member.

For example, referring to Figures 28 to 33, a valve member 92 may be employed which is similar to the conventional valve member 26 of Figures 8 and 9, except that the seal 44 is disposed deeper into the valve member 92 so as to provide a deeper recess 75 of diameter D2 slightly larger than the diameter Dl of the tip 53 of the nozzle 94. The nozzle 94 is similar to the nozzle 52 of Figure 11 except that part-way along its length it has a portion of increased diameter with an annular groove 96 formed in it. The annular groove 96 has inclined sides. A number of axial passageways 98 extend from the tip 53 of the nozzle 94 surrounding the annular ridge 56 to the groove 96. An 0-ring 100 or other form of resilient band is fitted to the annular groove 96 so that when it is sitting in the groove 96 it is in tension. It will therefore be noted that, when the backpressure in the chamber 86 rises beyond a particular level, the 0-ring 100 will lift away from the groove 96 and permit water to flow from the chamber 86 along the passageways 98, past the 0-ring 100 and out through the outlet port 30. It will be noted that, with this modification, the float valve assembly 102 has only one additional component, the 0-ring 100, as compared with the conventional float valve assembly 10.

-10 -The invention may also be applied to diaphragm valves, for example to British Standard BS 1212, Part 2 (1990).

Figures 33A & B show the nozzle 20 and diaphragm moulding 104 of a conventional Part 2 float valve in its open and closed positions, respectively. The conventional nozzle 20 is similar to the conventional nozzle 20 of the Part 1 valve described with reference to Figure 7 of the drawings. The diaphragm moulding 104 has an outer annular mounting portion 106, a central thickened sealing portion 108 and a flexible diaphragm portion 110 joining the mounting portion and the sealing portion 108. The nozzle 20 and diaphragm moulding 104 are mounted in a body (not shown) having an outlet port. Water is supplied from the left into the nozzle 20. A float arm (not shown) acts to urge the sealing portion 108 against the tip of the nozzle 20 when the water level rises.

One modification to the conventional Part 2 float valve so as to embody the invention is shown in Figures 34A & B. The conventional nozzle 20 is replaced by a nozzle 94 similar to that described above with reference to Figures 28 to 30. The conventional diaphragm moulding 104 is replaced by a diaphragm moulding 112 which is similar to the conventional diaphragm moulding 104 described above with reference to Figures 33A & B, except that a peripheral wall 114 is formed around the sealing portion 108 so that the tip 53 of the nozzle 94 and the peripheral wall 114 act in a similar manner to that described above when the tip 53 of the nozzle 94 enters the recess 75 formed by the peripheral wall 114 as the valve closes.

Another modification to the conventional Part 2 float valve so as to embody the invention is shown in Figures 35A & B. The conventional diaphragm moulding 104 as described with reference to Figures 33A & B is employed. The conventional nozzle 20 is replaced by a nozzle 116 similar to that described above with reference to Figures 28 to 30 except that a peripheral wall 118 is formed around the tip 53 of the nozzle 116 so that the peripheral wall 118 act in a similar manner to that described above when the raised central sealing portion 108 of the diaphragm moulding 104 enters the recess 75 formed by the peripheral wall 118 as the valve closes. It will be noted that the arrangement of Figures 35A & B employs the identical parts to the conventional Part 2 valve of Figures 34A & B, except for a different nozzle 116 with its 0-ring 100.

It should be noted that the embodiments of the invention has been described above purely by way of example and that many other modifications and developments may be made thereto within the scope of the present invention.

Claims

-11 -CLAIMS(The reference numerals in the claims are not intended to limit the scope of the claims.) 1. A float valve assembly (50; 102) for connection to a water supply, comprising: a first member (52;94; 116) having an opening (58) arranged to be fed by the water supply; a second member (54;92;112;104), one (54;92;112;114) of the members being movable between (i) a closed position in which the second member blocks the opening and closes off the water supply and (ii) an open position in which, in use, water can flow from the opening to a space (86) between the first and second members and thence to an outlet (30,32) of the float valve assembly; an operating member (36) connected to, or for connection to, a float (78) and coupled to the movable one of the members so that, in an in use orientation of the float valve assembly, rising of the float from a lower position to an upper position causes the movable member to move from the open position to the closed position; and a restrictor (53,75;53, 114; 108,118) disposed downstream of the opening for restricting the flow of water from said space to the outlet so that a backpressure can be produced in said space acting to urge the movable member towards the open position; characterised in that: the restrictor is coupled to, or provided at least in part (75; 114; 108) by, the movable member such that the degree of restriction (88) when the movable member is in the open position is less than it is part way between the open and closed positions.
2. A float valve assembly as claimed in claim 1, wherein: one of the members (54;92; 112; 116) has a recess (75) facing the other member (52;94;104); and the other member has a projecting portion (53;108) which is disposed in the recess at least when the movable member is at and adjacent its closed position.
3. A float valve assembly as claimed in claim 2, wherein: the projecting portion is not disposed in the recess when the movable member is in the open position.

-12 -
4. A float valve assembly as claimed in any preceding claim, wherein: the second member has a seal (61; 108) for engaging the first member to block the opening when the movable member is in the closed position.
5. A float valve assembly as claimed in claim 4 when dependent on claim 2 or 3, wherein: the recessed member is provided by the second member; and the seal is provided at the base of the recess.
6. A float valve assembly as claimed in claim 4 and 5, further including: a pressure relief valve (62,68;96, 100) which is operable to bypass the restrictor at high values of the backpressure.
7. A float valve assembly as claimed in claim 6 when dependent on claim 5, wherein: the second member has a body (60) to which the seal is mounted; and the pressure relief valve is provided by the seal being movable relative to the body in a direction away from the first member against the action of a spring (68) to open a passageway past the seal from said space to the outlet.
8. A float valve assembly as claimed in claim 6, wherein: the pressure relief valve is provided on the first member and communicates with said space by at least one passageway (98) extending through the first member.
9. A float valve assembly substantially as described with reference to: Figures ito 6 and 11 to 27 or 28 to 32, or Figures 1 to 6 and 28 to 32, or Figures 34A & B; or Figures 35A & B of the drawings.