Plumbing overflow

Abstract

An overflow device for use with sinks and the like is described. The overflow device comprises a body adapted to be positioned adjacent the exterior of a sink bowl, the body having an inlet and an outlet joined by an inverted-U siphon passage, and a vent adapted to communicate ambient air to the top of the siphon passage, the vent being arranged to close when water level in the sink reaches a predetermined level. In at least one embodiment the vent has no moving parts.

Claims

1. An overflow device for use with a plumbing installation, a basin or a bath, the overflow device comprising: a body adapted to be positioned adjacent an exterior of the plumbing installation, the body comprising a first passage, a second passage, a third passage, and a cap covering an upper end of each passage, wherein the first and second passages are divided by a first passage member and wherein the first and second passages together with an interior volume of the cap form an inverted-U shaped siphon passage, wherein the first and second passages define an inlet and an outlet joined by the inverted-U shaped siphon passage; and the third passage together with a part of the cap forms an air valve, wherein an upper portion of the cap defines an entry port, the entry port being separated from an upper end of the first and second passages by an inverted weir, wherein the inverted weir extends downwardly from an upper end of the third passage such that its lowest point is below an upper end of a second passage member dividing the third passage from the first and second passages, and wherein the air valve is operable to communicate ambient air to a top of the inverted U-shaped siphon passage and wherein the air valve is arranged to close when water level in the plumbing installation increases to a predetermined overflow level thereby creating a siphon effect and wherein the air valve is arranged to open when the water level in the plumbing installation decreases from the predetermined overflow level thereby breaking the siphon effect.

2. The overflow device of claim 1, wherein the air valve has no moving parts, wherein opening and closing the air valve is effected by water levels within the plumbing installation and the inverted U-shaped siphon passage.

3. The overflow device of claim 1, wherein the entry port is located on an upper portion of the cap at or adjacent a point of highest elevation of the overflow device.

4. The overflow device of claim 3, wherein the entry port is on an upper surface of the cap and lies in a substantially horizontal plane.

5. The overflow device of claim 1, wherein the air valve comprises an exit port defined by a space provided between an uppermost point of the second passage member and the weir, the exit port permitting air from the entry port to enter the inverted-U shaped siphon passage to breakdown siphonic flow.

6. The overflow device of claim 5, wherein the exit port lies in a plane perpendicular to an entry port plane.

7. The overflow device of claim 5, wherein the entry port and the exit port define a convoluted flowpath therebetween.

8. The overflow device of claim 1, wherein the body defines an upper body portion and a lower body portion, the upper and lower body portions being arranged telescopically and sealingly connected, and said upper and lower body portions cooperating to define the first, second, and third passages.

9. The overflow device of claim 8, wherein the lower body portion defines the inlet and the outlet.

10. The overflow device of claim 1, wherein the inlet and outlet are provided with swivel elbows to facilitate installation.

11. The overflow device of claim 1, wherein the overflow device further comprises an air vent, the air vent adapted to vent air from the overflow device and/or pipework associated with overflow device.

12. A waste and overflow arrangement comprising an overflow device as defined in claim 1 in combination with a sink outlet waste fitting; the waste fitting having a sealing member movable between an open position allowing water to drain from the sink and a closed position retaining water within the sink; the waste fitting having a first fluid connection above the sealing member and a second fluid connection below the sealing member; and the overflow arrangement further comprising a first fluid conduit between the first fluid connection and the inlet and a second fluid conduit between the second fluid connection and the outlet.

13. The waste and overflow arrangement of claim 12, wherein the first and second fluid conduits are respective pipes and the first and second fluid connection and the inlet and outlet each comprises a pipe connector.

14. The waste and overflow arrangement of claim 12, wherein the waste fitting includes an air vent in communication with an interior of the waste fitting below the sealing member.

15. The waste and overflow arrangement of claim 12, wherein the body is adapted to be attached to a drain hole in a sink; and said sealing member is movable within the body between an open position allowing water to drain from the sink and a closed position retaining water within the sink.

16. The waste fitting of claim 15, wherein the waste fitting includes a connection below the sealing member for fitting an air vent means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will now be described, by way of example, with reference to the drawings, in which:

(2) FIG. 1 is a perspective view of one embodiment of overflow arrangement according to the present invention;

(3) FIG. 2A is a similar view illustrating operation in a drain mode;

(4) FIG. 2B is a similar view illustrating operation in an overflow mode;

(5) FIGS. 3A, 3B, 3C, 3D, 3E, and 3F show a front cross-sectional view of part of the apparatus, showing a sequence of operations;

(6) FIG. 4 is a view similar to FIGS. 3A, 3B, 3C, 3D, 3E, and 3F showing a preferred sealing arrangement;

(7) FIG. 5A is a perspective view of a modified embodiment;

(8) FIG. 5B is a plan view corresponding to FIG. 5A; and

(9) FIGS. 6 and 7 are cross-sectional views of further modified embodiments.

DESCRIPTION OF PREFERRED EMBODIMENTS

(10) Referring to FIG. 1, a waste and overflow assembly for a sink or the like comprises a waste fitting 10 and an overflow device 12 connected by two pipes 14 and 15.

(11) The waste fitting 10 in this embodiment is of the type having a basket strainer and integral sealing plug, and comprises a flange 16 and an underbody 18 which screw together to engage with a sink opening. A strainer basket 20 is mounted on a movable stem 22 which also carries a sealing disc 24 which can be engaged against the underbody 18 to close the waste fitting 10.

(12) The underbody 18 has a first boss 26 above the sealing disc 24 and a second boss 28 beneath the sealing disc 24, in which the pipes 14 and 15 are secured by backnuts 30 and seals 32.

(13) The overflow device 12 comprises a lower body portion 34, a telescopic upper body portion 36 comprising a passageway portion 37 and a cap 38, and will be described in greater detail below. The lower body 34 is provided with removable covers 48 to allow access to clear blockages.

(14) FIG. 2A shows the overflow device 10 in a draining mode, in which the strainer basket 20 and sealing disc 24 are in a raised position. In this mode water in the sink passes directly to the drain. FIG. 2B shows the overflow device 10 in overflow mode. Here, the sealing disc 24 is engaged to retain water in the sink. If the water rises above a predetermined level in the sink it overflows via the pipes 14 and 15 and the overflow device 10 to drain beneath the sealing disc 24, as will now be explained more fully.

(15) Referring to FIGS. 3A, 3B, 3C, 3D, 3E, and 3F, the lower body portion 34 and the upper body portion 36 together form three passages A 60, B 62 and C 64. Passages A 60 and B 62 are separated by a passage member 63 and together with an interior volume of the cap 38 form a siphon. Passage B 62 and passage C 64 are separated by a further passage member 65. Passage C 64 together with the remainder of the cap 38 form a non-mechanical air valve (i.e. a valve with no moving parts) having an air entry port 40 and an inverted weir 42. The inverted weir 42 extends downwardly from an upper end 66 of the passage C 64 such that its lowest point 68, in use, is below an upper end 70 of the further passage member 65. The sequence of events shown in FIGS. 3A, 3B, 3C, 3D, 3E, and 3F will now be described.

(16) First the water level in passages B 62 and C 64 mirrors the level in the sink bowl (FIG. 3A). In FIG. 3B, the water level reaches the predetermined overflow level. Water begins to drain into passage A 60. The level in passage C 64 continues to match the level in the sink bowl. As the level in the sink bowl increases (seen in tube C 64), the air valve 40 is shut off. Drainage speed now increases due to the syphonic effect on the water in passage B 62. Referring to FIG. 3D, a syphon is fully formed and drainage speed increases to its maximum level (in a preferred example, 19 liters/min). Once the syphonic flow is set up the level in the basin sink bowl starts to drop, the level in passage C 64 dropping, continually matching the level in the sink bowl, allowing the air valve 40 to open (FIG. 3E). FIG. 3F shows air entering the overflow chamber, breaking the siphon.

(17) It will be noted that both the feed pipe 14 and the return pipe 15 remain open at all times regardless of mode of operation. No valves are required in these parts.

(18) Referring to FIG. 4, in the preferred embodiment the upper body 36 telescopes within the lower body 34 such that the height of the overflow device 12 is adjustable. The upper body 36 is moulded with blade seal rings 44 which eliminates the need for rubber seals such as O-rings. FIG. 4B shows the cross-section of the blade seal rings. In alternative forms of the invention, the telescopic adjustment may be dispensed with, and the overflow device 12 formed as a rigid unit of fixed length.

(19) FIG. 5 shows a modified embodiment in which the pipes 14 and 15 are attached to the overflow device 12 via swivel elbows 46. This allows the assembly to be manoeuvred to avoid obstacles under the worktop such as taps or pipework. FIG. 5B indicates the range of angular variation which can be achieved.

(20) The embodiments described above can suffer a problem when used with certain traps and U-bends in the downstream waste system, in that when the waste plug is closed an air bubble or air lock can form between the overflow device and the traps or U-bend, impeding or preventing flow from the overflow device. The embodiments of FIGS. 6 and 7 overcome this.

(21) In FIG. 6, an air inlet is provided in the form of a standpipe 50 which admits air into the underbody 18 below the sealing disc 24, thus preventing the formation of an air bubble in the downstream waste system. The standpipe 50 extends above the level of the cap 38 to prevent overflow of water from it.

(22) The same function is performed in FIG. 7 by a one-way air admission valve 52; such valves are well known per se.

(23) The invention thus provides a concealed overflow arrangement which can be achieved without the use of moving parts and will thus be simple to manufacture and reliable in operation.