WASTE WATER UNIT

The present invention relates to a waste water unit, particularly but not exclusively for pumped domestic drainage, such as from a shower or a sink.

Floats are known to be incorporated in waste water units to allow control of a pump. When the float rises, due to waste water being present in the waste water unit, a float switch is triggered, causing the pump to activate, thus drawing water through the waste water unit.

However, such a float switch allows only ON and OFF operation of the pump.

A further problem exists in that waste water units, and in particular pump- assisted units, often transmit undesirable noise back through the unit.

The present invention seeks to provide a solution to these problems.

According to a first aspect of the invention, there is provided a waste water unit for pumped domestic drainage, the unit comprising: a waste body; a waste water inlet through which waste water enters the body; a waste water outlet for connection to a drain; and a switch device for controlling a pump which, in use, causes at least part of the said waste water to flow from the waste body through the waste water outlet; the switch device having a float element in the waste body, and pump setting means for setting the pump to a first non-pumping condition, a second pumping condition at which

the pump operates to provide a second waste water flow rate, and a third pumping condition at which the pump operates to provide a second waste water flow rate which is higher than the first waste water flow rate, the condition set by the pump setting means being controllable by the position of the float element; characterised in that the float element includes a magnetic element for controlling the pump setting means, and the pump setting means includes two or more magnetically operable switch elements for setting at least two of the said conditions.

Preferable and/or optional features of the first aspect of the invention are set forth in claims 2 to 16, inclusive.

According to a second aspect of the invention, there is provided a waste water unit for domestic drainage, the waste water unit comprising : a waste body; a waste water inlet through which waste water enters the body; a waste water outlet for connection to a drain; and a float element which is located in the waste body and which has a closing portion for closing or substantially closing the waste water outlet, so that waste water flow is gradually stopped as the waste water flow rate decreases and/or stops, and/or noise is muffled.

Preferable and/or optional features of the second aspect of the invention are set forth in claims 18 to 22, inclusive.

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

Figure 1 is a diagrammatic in use vertical cross-section taken through a first embodiment of waste water unit in accordance with the invention, showing a float element in an open condition and, in faint , in a closed condition;

Figure 2 is a diagrammatic in use vertical cross-section taken through a second embodiment of a waste water unit in accordance with the invention.

Referring firstly to Figure 1 of the drawings, there is shown a first embodiment of a waste water unit 10 for pumped domestic drainage, such as from a shower or sink. The waste water unit 10 comprises a waste body 12, which may or may not include a trap, a waste water inlet 14 through which waste runoff water from, for example, the shower or sink, enters the waste body 12, and a waste water outlet 16 for direct or indirect connection to a drain.

In the embodiment shown in Figure 1, the waste water inlet 14 is intended to be connected to the water outlet of a, typically electric, pump (not shown), and is thus provided at the side of the waste body 12. As such, a releasable access cover 18 is provided at the in use top of the waste body 12 to allow access to the interior of the waste body 12 for cleaning and maintenance.

It will, however, be appreciated that, when the unit 10 is upstream of the pump, thus being connected indirectly via the pump to the drain, the waste water inlet 14 can be provided at the top of the waste body 12 to allow direct draining from a shower or

sink area. Such a unit is shown, by way of example, in Figure 2. The access cover is still provided in this configuration.

The waste water unit 10 also includes a switch device 20 for controlling the operation of the pump. The switch device 20 includes a float element 22 slidably received on a spigot 24 in the waste body 12, and a plurality of discrete magnetically operable reed switches 26 mounted as a block 28 on, or adjacent to, an exterior surface 30 of the waste body 12, and below the access cover 18. The reed switches 26 are stacked in, or substantially in, parallel with the spigot 24.

Each reed switch 26 is connected to control circuitry (not shown) by which the speed, and thus the pumping flow rate, of the pump is stepwisely controlled.

The float element 22 includes a magnetic element 32, typically being a permanent magnet. The magnetic element 32, in this case, is embedded within the float element 22, but may be positioned on an exterior surface of the float element 22.

Although the float element 22 is spaced from the block 28 of reed switches 26, the magnetic element 32 is oriented to travel in close proximity to the reed switches 26. To maintain this orientation, the spigot 24 has a non-circular lateral cross-section, such as triangular, and an aperture 34 of the float element 22 in which the spigot 24 is received is complementarily shaped. Other arrangements can of course be provided, such as splines and/or keyways.

The reed switches 26 and the magnetic element 32 of the float element 22 are positioned relative to each other, so that the first reed switch 36 which deactivates the pump is located at a level at, or adjacent to, the lowest position to which the float element 22 will fall when in use.

The second reed switch 38 which controls the pump to operate at a first relatively low pumping flow rate is located at a level at which the float element 22 will start to rise as waste water enters the waste body 12.

The third reed switch 40 which controls the pump to operate at a second pumping flow rate which is greater than that of the first pumping flow rate is located at a level, for example midway along the spigot 24, at which the float element 22 rises further due to an increase in the volume of waste water in the waste body 12.

The fourth reed switch 42 controls the pump to operate at a third pumping flow rate, which is greater than that of the second pumping flow rate and which is, preferably, the maximum pumping flow rate of the pump. The fourth reed switch 42 is located at a level which is at, or adjacent to, the highest position to which the float element 22 will rise when in use.

As will be appreciated, the speed of the pump is controlled in a stepwise fashion directly and solely by the float element 22 as it moves along the spigot 24 and the magnetic element 32 activates an adjacent reed switch 26. Those reed switches 26 at which the magnetic element 32 is not adjacent assume a deactivated state. However, to

smooth an operating transition of the pump, circuitry can be provided to allow a ramp up and ramp down period.

Monitoring circuitry is also provided so that, if waste water is flowing into the waste water unit 10, but the pump is not activated, the shower or other water discharge device is deactivated.

The first reed switch 36, which deactivates the pump, can be dispensed with. In this case, logic control, for example, can be utilised in which, if none of the other reed switches 26 are activated, then the float element 22 must be at the lowest level and the pump is switched off.

The second reed switch 38 or third reed switch 40 can also be dispensed with, thereby simply providing a choice between a low pumping flow rate and a high pumping flow rate.

Alternatively, one or more further reed switches can be provided to allow finer stepwise increments in pumping flow rate.

Although reed switches are suggested, any suitable type of remotely operable switch can be utilised, such as a Hall Effect switch.

The float element 22 itself includes a closing portion 44 for closing or substantially closing the waste water outlet 16. In the present case, an opening 46 to the

waste water outlet 16 is located in the bottom surface 48 of the waste body 12, and the ύ spigot 24 extends therethrough. The opening 46 of the waste water outlet 16 defines a seat 50 on which the closing portion 44 of the float element 22 sits when in its lowest condition.

The closing portion 44 of the float element 22 is a taper formed on the lower part of the float element 22. In this case, the taper is a frusto-conical portion 52 formed on the float element 22, but it may be an arcuate surface, or chamfer, for example.

As the waste water flow decreases and/or stops, the closing portion 44 first gradually slows the water flow into the waste water outlet 16, before then seating in the opening 46 to the waste water outlet 16 and stopping the flow completely. The slowed flow rate decreases the likelihood of 'gurgling' and 'sucking' noises, and prevents the pump from suddenly running in a dry state. Furthermore, by restricting the waste water outlet opening 46, pump noise is prevented or limited from travelling back to the user area.

To prevent suction engagement, due to pressure difference for example, of the float element 22 in the waste water outlet 16, a vent element (not shown), such as a one- way valve, can be utilised. The vent element is provided between the waste water outlet 16 and the waste body 12, or on the float element 22 itself.

Regarding Figure 2, there is shown a second embodiment of a waste water unit 110 for pumped domestic drainage. The unit 110 shown is intended for connection

upstream of the pump. However, the arrangement is equally applicable to a unit intended for connection downstream of a pump.

Parts similar to those of the first embodiment have similar references, and further detailed description will be omitted.

This waste water unit 110 comprises a waste water inlet 114 at or adjacent to a removable access cover 118, a waste body 112 into which waste runoff water drains via the waste water inlet 114, and a waste water outlet 116 which is connected to a, typically electric, pump (not shown).

As before, a switch device 120 is included for controlling operation of the pump.

The switch device 120 includes a float element 122, and a plurality of discrete magnetically operable switches 126, as described above, mounted in stacked fashion on, or adjacent to, an exterior surface 130 of the waste body 112, and below the access cover 118.

The float element 122 includes a cranked float arm 154, pivotably mounted at the crank to the interior bottom surface 148 of the waste body 112. A float body 156 is provided at, or adjacent to, one end of the float arm 154, remote from the plurality of switches 126. A magnetic element 132 is provided, either on or embedded within, an end of the float arm 154 opposite the float body 156.

With little or no waste water flowing into the waste body 112, the float body 156

of the float element 122 resides at its lowest position, and the magnetic element 132 is at the highest position. Consequently, in this embodiment, a first switch 136 is positioned at the top of the stack of switches 126 and, via the influence of the adjacent magnetic element 132, controls the pump to be in a deactivated condition.

As waste water flows into the waste body 112, the float body 156 rises, causing the magnetic element 132 to fall. Once adjacent to a second switch 138, below the first switch 136, the second switch 138 is operated, causing the pump to operate at a first pumping flow rate.

As the waste water flow into the waste body 112 increases, the float body 156 rises still higher, and the magnetic element 132 falls lower. Once adjacent to a third switch 140, below the second switch 138, the third switch 140 is operated, causing the pump to operate at a second pumping flow rate which is greater than the first pumping flow rate.

As with the first embodiment, only two switches 126 can be used to provide two different pumping flow rates in addition to a deactivated state. Alternatively, three or more switches 126 can be used.

Although not shown, the float element can, in this embodiment, be configured to close or substantially close the waste water outlet as the float body lowers.

The pivotable float arm can include a plurality of one magnetic elements,

typically being three. In this case, the magnetic elements are arranged, preferably stacked, to close the magnetically operable switches as the end of the float arm opposite the float body falls. This provides a progressive indication of water level within the waste unit.

The waste water units described above can be provided and purchased as a kit of parts. They can be retrospectively fitted to previously installed pumped waste systems, and thus do not need to be purchased with the pump.

The float element with closing portion can be used on any waste water unit in which the float element can close or substantially close the waste water outlet. For example, the waste water unit may be gravity assisted, instead of pump-assisted. In this case, the closing portion of the float element helps eliminate or reduce odours and sounds travelling back through the pipework to the user area.

It is thus possible to provide a variable pumping flow rate through the use of a float switch. It is also possible to provide a reduction in noise transmitted through the drainage system by, for example, the pump.

The embodiments described above are given by way of examples only, and modifications will be apparent to persons skilled in the art without departing from the scope of the invention as defined by the appended claims. For example, the float body of the second embodiment can be adapted to function as a closing portion, by which the waste water outlet is gradually closed.