GB2195763A - Water tap - Google Patents

Abstract

An automatic tap has a differential light sensor 10 adapted for mounting on the water outlet nozzle of the tap, the sensor having an infra-red transmitter T and a pair of radiation receiving elements R. The transmitter T is positioned closer one receiving element R than the other, and that one receiving element R has an optical filter 12 associated therewith. A control circuit operates on the outputs of the receiving elements R and causes an electrical water flow valve to be operated dependent upon the detection of the presence of an object e.g. hands beneath the sensor. <IMAGE>

Description

SPECIFICATION Water tap This invention relates to water taps, and in particular (but not exclusively) to taps intended for fitting to a sink or hand basin to control the flow of water into the sink or basin, and to means to improve the operation of an existing tap.

Sinks, hand basins and the like are normally fitted with at least one tap, to control the flow of water thereinto. Often two taps are provided, one each respectively for the hot and cold water supplies though in recent years considerable use has been made of mixer taps adapted to allow a single stream of water at a desired temperature to flow into the basin, blended from the hot and cold water supplies. Some designs of mixer taps have separate controls respectively for the hot and cold water supplies, though many modern designs employ a single control for the flow rates of both supplies.

All conventional taps requires a positive action by a user, to cause water to flow into a basin, and this leads to certain well known disadvantages. For example, should a user's hands be dirty, the taps inevitably also will become soiled when the water flow is commenced. Another disadvantage of most conventional designs of tap is that a positive action must be taken in order to turn off the supply of water. Often, people are careless about this and so leave a tap at least partially, on, leading to significant waste. Apart from the economic disadvantage of such waste, in many countries potable water is relatively scarce and it is important great care is always taken not to waste the water supply in this way.

In many public buildings, including all kinds of institutions, taps which automatically turn off the water supply after a given period of time are frequently fitted, in order to eliminate excessive wastage. One common design of tap of this type has a valve mechanism with a control knob which must be depressed to cause water to flow; the knob is automatically returned to its initial position so turning off the supply within a relatively short period of the knob being released. Though greatly reducing the risk of waste, such a tap is not particularly convenient to use, especially if both hot and cold water is to be run into a sink or basin.

It is a principal aim of the present invention to provide a water tap suitable for fitting to a basin or sink, and which is able at least to reduce the disadvantages discussed above for conventional designs of water tap. The object of the invention is thus to provide a tap which is simple and hygienic to use, and which serves to eliminate water wastage.

Accordingly, a first aspects of this invention provides a water tap including a water outlet nozzle, sensor means adapted to detect the presence of an object in the region below the nozzle which sensor means includes a radiation transmitter and at least two spaced-apart radiation receiving elements to detect reflected radiation emanating from the transmitter, each radiation receiving element being arranged to produce a respective electrical output signal, an electrically-operated flow valve to control the flow of water out of the nozzle and a control circuit operating on the respective output signals from the radiation receiving elements and arranged to control the actuation of the flow valve dependent thereon.

It will be appreciated that the tap of this invention operates automatically, in that water is allowed to flow out of the tap whenever an object (such as a user's hand) is placed generally beneath the water outlet nozzle, but which tap terminates the supply of water when the object is removed. Water will thus run only when actually required. However, apart from eliminating water wastage, the tap also is most hygienic to use, in that no physical contact need be made with any kind of operating knob, lever or the like when hands are soiled, in order to cause the water to flow so enabling the washing of one's hands. The tap of this invention therefore will display particular benefits for workers in dirty environments, or in various public buildings such as hospitals and mental institutions, and also in kitchens and so on.

It is most important that the sensor means is able to operate reliably notwithstanding variations in ambient lighting, the reflectivity of objects placed below the sensor means, and so on. This is achieved by having the control circuit operating on the electrical output signals of the two spaced apart receiving elements and controlling the flow valve dependent thereon. Reliability of operation may be enhanced by having one of the two receiving elements associated with attenuating means, the control circuit operating on a differential basis on the attenuated electrical output signal of that receiving element as well as on the electrical output signal of the other receiving element.Such attenuating means could operate electrically, on the output signal of the receiving element associated therewith, or the reflected radiation falling on that receiving element could be attenuated, for example by means of a filter positioned in front of that element.

For an arrangement as described above, it is greatly preferred for the transmitter to be positioned closer to the receiving element having attenuating means associated therewith then the other receiving element in order to allow the control circuit to operate on a differential basis, to detect an object placed in the detection region of the sensor. In this case, when no object is present in that region, the control circuit may produce a negative output, because the output of said one receiving element having attenuating means will be lower than the output of said other receiving element.

When however and object is placed in the detection region, the control circuit may produce a positive output because the existing balance between the two receiving element outputs is distributed. The positioning of the transmitter closer one receiving element ensures that the positioning of an object in the detecting region mainly influences that one receiving element. In this way, it is found that better discrimination of the positioning of an object beneath the sensor may be obtained, despite changes in ambient lighting or other variable factors.

The radiation emanating from the transmitter could be in the visible spectrum, but advantageously is in the infra-red region to assist reliable operation even in adverse conditions.

When attenuating means is provided, that means associated with one of the receiving elements preferably comprises an optical filter which blocks visible light but which is tran sparent to infra-red radiation, whereby infra red radiation which has been reflected from an object adjacent the sensor means is able to fall on that receiving element.

Each receiving element could be either a passive device or an active device, as re quired. In the latter case, the output signal from each device may directly be produced by the device, but in the former case an exter nally-applied signal may be conditioned by the device. Advantageously, the receiving ele ments have directional characteristics, and are positioned to receive radiation generally from the region below the nozzle of the tap.

The electrically-operated-fiow valve conveniently comprises a solenoid valve, arranged fully to open upon current being supplied thereto. The tap of this invention may therefore include a manually or electrically pre-settable flow control valve, in order to regulate the water flow to a desired value when the solenoid valve has opened. The tap may thus resemble a conventional tap, including a knob for control of the water flow rate, but with the on/off flow control being performed by the solenoid valve.

The control circuit must be able to sense the outputs of the receiving elements of the sensor means and control the electrically oper ated flow valve dependent thereon. In the case of a solenoid valve, the control circuit may include an electronic switch for current supplied to the solenoid valve, and a comparator circuit operating on outputs from the re ceiving elements and controlling the electronic switch dependent thereon. For some applications, it may be desirable to include a delay circuit, to ensure that the electrically controlled valve remains open for a pre-determined period of time following either the detection of the presence of an object below the water outlet nozzle, or the detection of the removal of an object from below the water outlet nozzle.In this way, stable operation may be achieved whilst at the same time ensuring an adequate flow of water for the desired purpose.

The tap of this invention may specially be constructed so as incorporate within the body thereof an electrically controlled flow valve, the sensor means and possibly also the control circuit, though this may conveniently be located at some point remote from the tap itself. However, the sensor means, flow valve and control circuit all may be fitted to an existing tap, either before the installation thereof to a sink or basin, or subsequent to such installation. Irrespective of this, it is preferred for the sensor means to be mounted on the spout of the tap adjacent the water outlet nozzle, so as to be able to detect the presence of an object between that outlet nozzle and the base of the sink bowl or basin into which water may run from the tap.

As mentioned above, an existing tap may be modified so as to be arranged in accordance with the present invention. Accordingly, a second aspect of the present invention provides a kit of parts for assembling to an existing tap, which kit comprises an object sensor means adapted to be mounted on a tap and having a radiation transmitter and at least two spaced-apart radiation receiving elements to detect reflected radiation emanating from the transmitter, each radiation receiving element being arranged to produce a respective electrical output signal when an object is move into the detection region of the sensor means, an electrically-operated water flow control valve adapted for mounting in a water pipe leading to the tap, and a control circuit having inputs for the electrical output signals from the receiving elements and adapted to control the flow of current to the electrically-operated flow valve dependent upon the sensor output signals.

By way of example only, certain specific embodiments of this invention will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 shows diagramatically the sensor of this invention, for fitting to a tap; Figures 2 to 4 show the operation of the sensor of Fig. 1, for various positions of the hand of a user; and Figures 5 to 7 respectively show three possible configurations for taps of this invention.

Referring initially to Fig. 1, there is shown a sensor S having a body 10 in which is mounted en infrared transmitter T and a pair of recessed receivers R, the transmitter T being positioned between the two receivers, but nearer the left-hand (in Fig. 1) receiver 11.

Associated with that receiver 11 is an optical filter 12 which is substantially opaque to vis ible ambient light but which is substantially transparent to infra-red radiation.

Also shown diagrammatically in Fig. 1 is a wall 13 of a sink, which wall 13 refiects most ambient light falling thereon, as diagrammatically illustrated by the beams 14 and 15. The right hand receiver 16 thus has a relatively large amount of ambient light falling thereon as compared to the amount of light falling on the left hand receiver 11, by virtue of the presence of the optical filter 12. The output of the infra-red transmitter T is relatively low, and the path length from the transmitter T to the wall 13 and back to the receivers R is relatively long, so that very little infra-red radiation is received by either receiver.Under normal lighting conditions, the infra-red radiation received by the two receivers can be ignored, and so the right hand receiver 16 detects a relatively large amount of radition (i.e. ambient light plus a very small amount of infra-red radiation) as compared to the left hand receiver 11.

The transmitter T conveniently is an infrared light emitting diode, supplied with current along wires 17 entering the sensor body 10.

Each receiver R may be a photoresistor, a photodiode or a phototransistor, depending upon the required sensitivity. Each receiver may serve to offer a variable resistance to the flow of an electrical current dependent upon the amount of light thereon, so conditioning an applied voltage. In this way, and for the situation illustrated in Fig. 1, a voltage applied to wire 18 connected to both receivers 11 and 16 is conditioned so that the voltage appearing on wire 20 from the right hand receiver 16 will be relatively high as compared to the voltage on wire 19, from the left hand receiver 11, Figs. 2 to 4 show the change in optical characteristics, should a hand be placed at least partially below the sensor S.A hand in general displays low reflective properties both to ambient and infra-red light and so should the hand be placed generally below the right hand receiver 16, as shown in Fig. 2, the amount of light falling on the right hand receiver is greatly reduced. Moreover, because the transmitter T is displaced to a position nearer receiver 11, the increase in infra-red radiation falling on the right hand receiver is relatively small. The consequence of this is that the voltage on wire 19 from the left hand receiver 11 now is relatively high as compared to the voltage appearing on wire 20 from the right hand receiver 16.

Should a hand be placed generally below the left hand receiver 11, the amount of infrared radiation falling on that receiver is significantly increased, so allowing the voltage on wire 19 to rise above that on wire 20. Should a hand be placed beneath both receivers, as shown in Fig. 4, the amount of ambient light falling on the right hand receiver 16 is greatly reduced, but the amount of infra-red radiation falling on the left hand receiver 11 is much increased; again, the voltage on wire 19 rises above that on wire 20.

From the foregoing, it will be appreciated that if no object is present beneath the sensor S, the voltage on wire 20 is higher than that on wire 19, but should a relatively non-reflective object (such as a hand) be placed anywhere beneath the sensor, the voltage on wire 19 rises to a value above that on wire 20. This differential change 10 may be deducted using a comparator and the output of the comparator C used to control an electronic switch ES, as illustrated in Fig. 5. Here, there is shown a mixer tap assembly 25 including a spout 26 having an outlet nozzle 27 and a flow control block 28 for hot and cold water supplies. A solenoid valve SN is mounted at the base of the spout 26, to control the flow of water therealong, from the block 28. Separate hot and cold supply pipes 29 and 30 are connected to the block 28, in the usual manner.

The sensor S is mounted on the spout 26, adjacent the outlet nozzle 27, for example by means of a suitable adhesive, wires connecting the sensor to a control circuit 31 as appropriate.

The control circuit 31 for the tap has a mains input lead 32 provided with a fuse 33 and a switch 34. A power supply unit PS supplies low voltage current to the sensor S, for the transmitter T and the receivers R, as well as the other components fitted within the circuit 31. The electronic switch ES is arranged to circuit 31. The electronic switch ES is arranged to control the supply of mains electricity to a water flow solenoid valve SN and the electronic switch is triggered either by the output of comparator C receiving at its inputs the conditioned signals from the two receivers R of the sensor S, or for manual (non-automatic) operation by current supplied from a switch 35.

Switch 34 may be used to turn on and off the entire automatic tap control, whereas switch 35 allows selection as between fun automatic control and normal manual control, using the valves (not shown) provided as a part of the mixer tap block 28 in a conventional manner.

Figs. 6 and 7 show arrangements similar to those of Fig. 5, but for installation on existing taps. In these Figures, parts similar to those illustrated in Fig. 5 are given like reference characters and will not be described again here.

Fig. 6 shows a conventional single tap 40, sensor S being fitted adjacent the outlet nozzle 27 of that tap. Solenoid valve SN is fitted in the water supply pipe 41 leading to that tap, and the control knob 42 of the tap may be used in a conventional manner to control the flow rate of water, whenever the solenoid valve SN is open.

Fig. 7 shows an arrangement generally similar to that of Fig. 6, but for the case of an existing mixer tap. Here, two separate solenoid valves SN are provided, one each in the hot and cold water supply pipes 48 and 49.

Both valves are controlled for simultaneous operation, by the electronic switch ES. In all other respects, the operation and function of the arrangement shown in Figs. 6 and 7 is essentially the same as that as has been described above, with reference to Figs. 1 to 5.

Claims (18)

1. A water tap including a water outlet nozzle, sensor means adapted to detect the presence of an object in the region below the nozzle which sensor means includes a radiation transmitter and at least two spaced-apart radiation receiving elements to detect reflected radation emanating from the transmitter, each radiation receiving element being arranged to produce a respective electrical output signal, an electrically-operated flow valve to control the flow of water out of the nozzle and a control circuit operating on the respective output signals from the radiation receiving elements and arranged to control the actuation of the flow valve dependent thereon.

2. A water tap according to claim 1, wherein attenuating means is associated with one of the two receiving elements, the control circuit operating on the attenuated electrical output signal of that receiving element as well as on the electrical output signal of the other receiving element.

3. A water tap according to claim 2, wherein the attenuating means operates electrically, on the output signal of the receiving element associated therewith.

4. A water tap according to claim 2, wherein the attenuating means acts on the reflected radiation, to attenuate that radiation before falling on said one received element.

5. A water tap according to any of claims 2 to 4, wherein the control circuit operates on a differential basis, acting on the attenuated output of said one receiving element and on the output of the other receiving element.

6. A water tap according to any of the preceding claims, wherein the radiation emanating from the transmitter is in the infra-red region.

7. A water tap according to claim 6 and in which attenuating means is employed, wherein the attenuating means associated with said one of the receiving elements comprises an optical filter which blocks visible light but which is transparent to infra-red radiation.

8. A water tap according to any of the preceding claims, wherein the radiation transmitter is positioned closeiy adjacent one of the two receiving elements.

9. A water tap according to any of the preceding claims, wherein the receiving elements have directional characteristics, and are positioned to receive radiation generally from the region below the nozzle of the tap.

10. A water tap according to any of the preceding claims, wherein the electrically-operated flow valve comprises a solenoid valve arranged fully to open upon current being supplied thereto.

11. A water tap according to claim 10, wherein the water tap includes a manually or electrically presettable flow control valve, to regulate the water flow to a desired value when the solenoid valve has opened.

12. A water tap according to any of the preceding claims, wherein the control circuit includes a delay circuit, arranged to have the electrically controlled-operated flow valve remaining open for a pre-determined period of time following either the detection of the presence of an object in the region below the water outlet nozzle, or the detection of the removal of an object from the region below the water outlet nozzle.

13. A water tap according to any of the preceding claims, wherein the sensor means is mounted on the spout of the tap adjacent the water outlet nozzle, so as to be able to detect the presence of an object between that outlet nozzle and the base of the sink bowl or basin into which water may run from the tap.

14. A water tap according to claim 1 and substantially as hereinbefore described, with reference to the accompanying drawings.

15. A kit of parts for assembling to an existing tap, which kit comprises object sensor means adapted to be mounted on a tap and having a radiation transmitter and at least two spaced-apart radiation receiving elements to detect reflected radiation emanating from the transmitter, each radiation receiving element being arranged to produce a respective electrical output signal when an object is moved into the detection region of the sensor means, an electrically-operated water flow control valve adapted for mounting in a water pipe leading to the tap, and a control circuit having inputs for the electrical output signals from the receiving elements and adapted to control the flow of current to the electricallyoperated flow valve dependent upon the sensor output signals.

16. A kit of parts according to claim 15, wherein one of the receiving elements has attenuating means associated therewith, so that the output signal from that receiving element is attentuated.

1 7. A kit of parts according to claim 16, wherein the radiation transmitter is arranged closer to one receiving element than the other.

18. A kit of parts according to claim 14 and substantially as hereinbefore described with reference to the accompanying drawings.