GB2469435A

GB2469435A - A Fluid Regulation device

Info

Publication number: GB2469435A
Application number: GB0901537A
Authority: GB
Inventors: Patrick Conroy
Original assignee: Touchtile Ltd
Current assignee: Touchtile Ltd
Priority date: 2009-01-30
Filing date: 2009-01-30
Publication date: 2010-10-20
Also published as: WO2010086662A1; GB0901537D0

Abstract

The fluid regulation device for regulating the flour of fluid through a valve, comprises: a valve 4 having one or more input ports 14, 16 for receiving fluid, and one or more output ports 18 for outputting fluid; and a drive stem 8 for driving the valve; a motor 2 coupled to the drive stem of the valve to drive the valve to regulate a flow of fluid between the input and the output ports; a controller 12 for controlling the motor in response to a desired flow of fluid through the valve; and a position detector 6,10 such as an optical encoder for detecting the position of the valve, the position detector being coupled to the drive stem of the valve, wherein the position detector is configured to output a first position signal dependent on a first detected position of the valve, and a second position signal, different from the first position signal, depending on a detected reference position of the valve, and wherein the controller controls the motor to drive the valve to a desired position in response to the first and second position signals to regulate the flow of a fluid flowing through the valve. Additionally(as shown in fig.8), a mixing valve for regulating fluid temperature which has hot and cold inputs with a common mixer output port. The mixer valve also being motor controlled independently of the flow valve.

Description

Fluid Regulation Device

FIELD OF THE INVENTION

This invention relates to fluid regulation devices for regulating the flow of fluid through valves. More particularly, the invention relates to the controlling of valves for regulating the temperature and/or flow of water.

BACKGROUND OF THE INVENTION

Devices for regulating the temperature and flow of water are known for example in EP 0,3 75,259. In this document, a mixer valve receives hot and cold water and outputs a mixture of the hot and cold water. The valve is driven by a motor through a sequence of gears and through a rotating-to-reciprocal converter to control the position of the mixer valve in order to achieve a desired temperature of the water. A separate, mechanical, temperature responsive actuator is also present to mechanically adjust the position of the valve, outside of any electronic control loop, to moderate the temperature of the mixed water. A separate solenoid valve controls the flow of water and a plurality of pipes and stop valves distribute the water to a number of outputs, for example a bath, shower and hand basin. The device uses an optical encoder on the output of the gears to interpret the position of the valve. However, the system configuration means that the position of the valve cannot accurately be determined, and therefore the resulting temperature of the mixed water, due to inherent tolerances of the following devices (converter, actuator etc). Furthermore, the device becomes quite bulky through the use of solenoid and stop valves.

Other systems use quadrature detection to detect the position and direction of a valve.

Such a technique requires the use of two sensors, such as optical sensors that are offset from each other. This offset allows the direction of movement to be determined. Since this technique requires two sensors, they can become bulky.

Also, it is also advantageous to be able to detect the end-stop of a valve before such a position is reached. Known techniques use micro switches and/or detect an increase in current consumption of the driving motor due to the motor stalling at the end-stop.

However, such techniques can be bulky, or have a detrimental effect on the longevity of the motor and/or valve.

The applicant has appreciated the need for an improved fluid regulation device that more accurately can determine a valve position and detect the valve's end-stop, and therefore can more accurately control the resulting flow of fluid from a device with a relatively small form-factor.

STATEMENT OF THE INVENTION

According to the present invention there is provided, a fluid regulation device for regulating the flow of fluid through a valve, comprising: a valve having one or more input ports for receiving fluid, and one or more output ports for outputting fluid, and a drive stem for driving the valve; a motor coupled to the drive stem of the valve to drive the valve to regulate a flow of fluid between the one or more input ports and the one or more output ports; a controller for controlling the motor in response to a desired flow of fluid through the valve; and a position detector for detecting the position of the valve, the position detector being coupled to the drive stem of the valve, wherein the position detector is configured to output a first position signal dependent on a first detected position of the valve, and a second position signal, different from the first position signal, depending on a detected reference position of the valve, and wherein the controller controls the motor to drive the valve to a desired position in response to the first and second position signals to regulate the flow of a fluid flowing through the valve.

The benefits of using a position detector for both position and reference and/or end stop detection are of reduced cost and much improved longevity of components. There is no need for additional detection components, such as micro-switches, which increases cost or detection of an increase in current consumption of a motor when the end-stop is reached (due to the motor stalling), which reduces the motor's longevity. By detecting the impending reference and/or end-stop of a valve using the signals from the single position detector, the motor driving the valve can be turned off before it hits its mechanical reference or end-stop position.

In embodiments of the fluid regulation device, the position detector comprises an optical encoder having an encoder portion defining a plurality of positions, each of the plurality of positions corresponding to a partially-open position of the valve, and the encoder outputting the first position signal for each of the positions; and wherein the optical encoder is coupled to the valve stem such that a change in the valve position corresponds to a change in encoder positions. By coupling the optical encoder to the drive stem of the valve, the controller can more accurate determine the absolute position of the valve, without the need for additional processing for taking into account manufacturing tolerances of components before the valve.

Preferably, the encoder comprises a reference encoder portion defining a reference position of the encoder that corresponds to the reference position of the valve; and wherein the encoder outputs the second position signal when the valve is in the reference position. The reference position provides the controller with a reference point from which to calculate it's absolute position. In embodiments, the reference position of the valve corresponds to the valve being substantially fully closed.

In embodiments, the encoder comprises an end-stop encoder portion defining an end-stop position that corresponds to an end-stop position of the valve; and wherein the encoder outputs a third position signal, different from the first and second position signals, when the valve is at the end-stop position. An end-stop position is useful for detecting actual end-stop position of the valve before the valve is driven too far.

In embodiments, the encoder portion comprises a plurality of equally-spaced apertures to allow light to pass therethrough, each aperture defining an encoder position, and each aperture having a width of less than or equal to the width of a receiving aperture of an optical sensor comprising the optical encoder. With slots of the above dimensions, an output of the encoder may be used to distinguish between the reference, mid-position and end-stop locations of the valve. Preferably, the first position signal comprises a substantially sinusoidal or triangular signal when the valve is moved from a first position to the next position.

In embodiments, the controller preferably processes the first position signal to determine a plurality of sub-positions between a first position and the next position, to which the valve is drivable, by comparing a detected portion of the first signal against a plurality of threshold levels. This allows a higher resolution of positions to which the valve may be driven.

In embodiments the reference portion comprises a blocking portion that prevents light passing therethrough, and having a width that is greater than the width of a receiving aperture of an optical sensor comprising the optical encoder. With a blocking portion, an output of the encoder may be used to distinguish between the reference, mid-position and end-stop locations of the valve.

In embodiments, the end-stop portion comprises an aperture to allow light to pass therethrough, the aperture having a width that is greater than a receiving aperture of an optical sensor comprising the optical encoder. With an end-stop portion having the above dimension, an output of the encoder may be used to distinguish between the reference, mid-position and end-stop locations of the valve.

In embodiments, the device comprising a coupler to couple the motor to the drive stem of the valve, and wherein the encoder is mounted on a portion of the coupler adjacent the drive stem of the valve. Alternatively, the output shaft of the motor and the drive stem of the valve may be manufactured as one piece, and the position detector spliced directly to the drive stem portion of the valve.

Preferably, the motor comprises a gearbox for reducing the number of output revolutions of the motor and for increasing the torque of the motor.

The present invention also provides a water regulation device for regulating the temperature and flow of water, comprising: a mixing valve for regulating the temperature of water, the mixing valve having a hot water input port for receiving hot water, a cold water input port for receiving cold water, a mixer output port for outputting a mixture of the input hot and cold water, and a drive stem for driving the valve; a flow valve for regulating the flow of water, the flow valve having an input port coupled to the output port of the mixing valve, one ore more output ports for outputting a regulated mixture of water, and a drive stem for driving the valve; a mixer motor coupled to the drive stem of the mixing valve to drive the mixing valve to regulate a temperature of the water output from the mixing valve, and a flow motor coupled to the drive stem of the flow valve to drive the flow valve to regulate a flow of water output from the device; a controller for controlling each of the motors in response to a desired temperature and flow of water through the device; a mixing valve position detector for detecting the position of the mixing valve, the mixing valve position detector being coupled to the drive stem of the mixing valve; and a flow valve position detector for detecting the position of the flow valve, the flow valve position detector being coupled to the drive stem of the flow valve, wherein each of the position detectors is configured to output a first position signal dependent on a first detected position of the respective valve to which the position detector is coupled, and a second position signal, different from the first position signal, depending on a detected reference position of the respective valve to which the position detector is coupled, and wherein the controller controls the mixer motor to drive the mixer valve to a desired position in response to the first and second mixing valve position signals to regulate the temperature of the water flowing through the device, and wherein the controller controls the flow motor to drive the flow valve to a desired position in response to the first and second flow valve position signals to regulate the flow of the water the device.

The benefits of using a position detector for both position and reference and/or end stop detection are of reduced cost and much improved longevity of components. There is no need for additional detection components, such as micro-swithes, which increases cost or detection of an increase in current consumption of a motor when the endstop is reached (due to the motor stalling), which reduces the motor's longevity. By detecting the impending reference and/or end-stop of a valve using the signals from the single position detector, the motor driving the valve can be turned off before it hits its mechanical reference or end-stop position.

In embodiments of the water regulation device, each of the position detectors comprise an optical encoder having an encoder portion defining a plurality of positions, each of the plurality of positions corresponding to a partially-open position of the respective valve to which the encoder is coupled, and the encoder outputting the first position signal for each of the positions; and wherein each of the optical encoders is coupled to the respective valve stem such that a change in the respective valve position corresponds to a change in respective encoder positions. By coupling the optical encoder to the drive stem of the valve, the controller can more accurate determine the absolute position of the valve, without the need for additional processing for taking into account manufacturing tolerances of components before the valve.

In embodiments, each of the encoders comprise a reference encoder portion defining a reference position of the encoder that corresponds to the reference position of the respective valve to which the encoder is coupled; and wherein the encoder outputs the second position signal when the respective valve is in the reference position. The reference position provides the controller with a reference point from which to calculate it's absolute position. In embodiments, the reference position of the valve corresponds to the valve being substantially fully closed.

In embodiments, each of the encoders comprise an end-stop encoder portion defining an end-stop position that corresponds to an end-stop position of the respective valve to which the encoder is coupled; and wherein the encoder outputs a third position signal, different from the first and second position signals, when the respective valve is at the end-stop position. An end-stop position is useful for detecting actual end-stop position of the valve before the valve is driven too far. Preferably, the encoder of the flow valve position detector comprises a second end-stop encoder portion defining a second end-stop position that corresponds to a second end-stop position of the flow valve; and wherein the encoder outputs a third position signal when the flow valve is at the second end-stop position. A second end-stop position is preferably used where the valve used has more than two locations, for example a divert valve.

In embodiments, the encoder portion comprises a plurality of equally-spaced apertures to allow light to pass therethrough, each aperture defining an encoder position, and each aperture having a width of less than or equal to the width of a receiving aperture of an optical sensor comprising the optical encoder. With an encoder portion having the above dimension, an output of the encoder may be used to distinguish between the reference, mid-position and end-stop locations of the valve.

In embodiments, the first position signal comprises a substantially sinusoidal or triangular signal when the valve is moved from a first position to the next position.

Preferably, the controller processes the first position signal to determine a plurality of sub-positions between a first position and the next position, to which the valve is drivable, by comparing a detected portion of the first signal against a plurality of threshold levels. This allows a higher resolution of positions to which the valve may be driven.

In embodiments, the reference portion comprises a blocking portion that prevents light passing therethrough, and having a width that is greater than the width of a receiving aperture of an optical sensor comprising the optical encoder. With a reference portion having the above dimension, an output of the encoder may be used to distinguish between the reference, mid-position and end-stop locations of the valve.

In embodiments, the water regulation device comprises a coupler to couple the respective motors to the drive stem of the respective valves, and wherein the respective encoder is mounted on a portion of the respective coupler adjacent to the drive stem of the respective valve.

Preferably, each of the motors comprise a gearbox for reducing the number of output revolutions of the motor and for increasing the torque of the motor.

Preferably, the water regulation device comprising a temperature sensor to detect a temperature of a mixture of water output from the mixing valve. In embodiments, the controller is configured to receive user input temperature data setting a desired temperature of the water output from the device, and is configured to control the mixer motor to drive the mixer valve in response to the first and second position signals, the user input temperature data and the detected temperature of the mixed water such that the temperature of the water output from the device is substantially equal to the desired temperature.

In embodiments, the controller is configured to receive user input flow data setting a desired flow of the water output from the device, and is configured to control the flow motor to drive the flow valve in response to the first and second position signals and the user flow data such that the flow of the water output from the device is substantially equal to the desired flow.

Preferably, the flow valve is a divert valve having at least two outputs and for diverting a flow of water to one of the at least two outputs. In preferred embodiments of the device, a first divert valve output is coupleable to a shower unit, and a second divert valve output is coupleable to a bath unit.

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

LIST OF FIGURES

Figure 1 shows a fluid regulation device; Figure 2 shows a position detector used in the device of figure 1; Figure 3A and 3B show further views of the position detector of figure 2; Figures 4A, 4B and 4C show example output waveforms from the position detector of figure 2; Figure 5 shows a flow chart for turning a valve on and off; Figure 6 shows a flow chart for optical encoder detection; Figure 7 shows different embodiments of the fluid regulation device of figure 1; Figure 8 shows a water regulation device; Figure 9 shows the output of the mixer valve of figure 8; Figure 10 shows the output of the flow valve of figure 8; Figures 11 A and 11 B show flow charts for water temperature tracking of the device of figure 8; and Figures 1 2A and 1 2B show flow charts for a diverter algorithms of the device of figure 8.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In brief, the present invention uses a single position detector, such as an optical encoder, to detect both the position and the reference and/or end-stop points of a valve. The position detector is located on the drive stem of the valve so that the control system can take into account any tolerances of any devices between the driving motor and the valve (for example gearboxes, rotating-to-reciprocal converters and the like).

Fluid Regulation Device Figure 1 shows a flow regulation device.

The flow regulation device comprises a motor 2 driving the drive stem 8 of a valve 4, which has one or more input ports 14, 16 and one or more output ports 18. The motor 2 may also comprise, or connect to the drive stem 8of the valve 4via, a gearbox (not shown) for stepping down the number of revolutions per minute and stepping up the resultant output torque of the motor. This allows cheap DC motors to be used to drive relatively larger valves where possible.

The flow regulation device also comprises a position detector 6, 10 having an output 20 connected to a controller 12. The position detector is coupled to the drive stem 8 of the valve 4. The controller 12 provides drive signals 22 to the motor to drive the valve in response to a desired valve location and the signals received from the position detector 6.

As the position detector 6 is coupled to the drive stem 8 of the valve 4, the positional feedback signals from the detector 6 corresponds to an absolute position of the valve 4.

Prior art solutions use detectors that are attached to the output shaft of the motor itself, which provides data that does not directly relate to the position of the valve due to manufacturing tolerances in the gearbox.

Position Detector Figure 2 and 3 show an encoder wheel that is used as a position detector in preferred embodiments of the system.

The encoder wheel comprises a plurality of slots 32 on an encoder portion of the encoder wheel, through which light may pass. The encoder wheel also comprises a larger slot section 26 that correspond to end-stop position and a reference position 24 that prevents light from passing through the wheel, which corresponds to a reference position. Additionally, the encoder wheel may also be provided with a second larger slot section 28 that corresponds to a second end-stop position.

As can be seen from figure 3A, light from a transmitter is transmitted to a receiver, and the various encoder wheel portions either pass light or prevent the light reaching the receiver.

The encoder wheel is designed for the optical sensor's receiver aperture and the valve's end-stop locations. This allows more accurate detection of the end-stops of the valve and prevents the electronic controller from driving the valve beyond its end-stop locations, which would results in the valve or the motor being destroyed.

In order for the electronics to determine the correct position of the valves used have a reference position at which a location value can be set to zero, and from which a relative position can be calculated. In order to accomplish this, the encoder wheel's also has a reference position that corresponds directly to the known reference position of the valve. The easiest way to accomplish this is to use the endstop of a valve, which corresponds to the end-stop indication on the encoder wheel. Therefore the valve and encoder wheel share a common reference. Without this reference the detected position and true position of the valve will not accurately correspond.

In the present invention, the valves used have a reference pin in their base that is aligned to their off position. There are also alignment grooves on the control shaft (or drive stem) of the valve itself that correspond to the end-stop location of the valve. Therefore the valve can be installed into the casting with a fixed orientation, the encoder wheel then installed onto the shaft of the valve using the alignment grooves on the shaft, followed by a circuit board that has an optical sensor aligned to the casting to correspond to the aligmuent of the valve. Therefore, when the valve is turned and the end-stop is detected by the optical sensor, it corresponds to the real end-stop of the valve.

The valves used in the present invention have an OFF section that is 10 degrees of rotation wide. Therefore, at any point within that 10 degrees of rotation, the valve will be in the off position stopping water flow. This means that the need to reach the physical end-stop of the valve to turn it off is not necessary and therefore allows the single optical sensor method of position and end-stop detection to reduce cost and longevity of components.

The aperture of the optical receiver 36 determines the slot 32 widths and distance between each slot. Preferably, the slot width is the less than or equal to the width of the optical receiver aperture. The distance between the centre of each slot 32 is preferably greater than or equal to the width of the receiver aperture (the distance being up to a maximum of two times the width of the aperture). With such a configuration, the optical encoder will produce a sinusoidal wave as the encoder is moved from one position to the next; each peak of the waveform corresponding to the centre of a slot 32.

The reference position is represented by a blocking portion that prevents light from passing therethough. Conversely, the end-stop positions are preferably represented by slots 26, 28 having widths greater than the width of a slot. As such, the optical encoder will produce a substantially minimum signal at the reference position (ie no light received), and a substantially maximum signal at the end-stop positions (ie maximum light received).

Figure 4a shows resultant voltages from the output of the encoder as the encoder is moved from one position to the next.

The top graph shows the resultant output when the preferable encoder slots dimensions are used. As can be seen, the reference position is denoted by a substantially minimum voltage, the end-stop by a substantially maximum voltage, and the mid-positions by a substantially sinusoidal wave having a maximum and minimum that differs from the maximum and minimum of the end-stop and reference positions.

As the motor is controlled to drive the valve, the resultant signal from the encoder therefore provides the controller with a signal that enables the controller to distinguish where the valve is, and whether or not an end-stop has been reached. If the controller detects the voltage dropping to substantially zero, it knows that the reference position has been reached, and may stop driving the valve in that direction. Similarly, if the controller detects that the voltage increases to a maximum (beyond the maximum voltage of a mid-position), then it knows it has reached an end-stop and may stop driving the valve in that direction. The controller may use threshold voltage levels to detect transitions from the mid-point to the reference and end-stop positions (shown as VO and V9 on the figures).

The second graph shows the situation where the slot widths, and the distances between each slot, are wider than the preferred dimension. In this situation, it can be seen that the maximum and minimum of the mid-positions substantially corresponds to the maximum of the end-stop position, and the minimum of the reference position.

To detect the reference and end-stop locations in this situation, controller would preferably count the time spent at either the maximum or minimum voltages whilst the valve is being driven. A time greater than a threshold value (ie greater than the time taken to go past the maximum or minimum of a mid-point slot position) would indicate that the respective reference or end-stop position has been reached and that the motor may be turned off.

A disadvantage of using such a time method to determine whether the reference or end-stop location has been reached, is that the encoder may stop at the lowest or highest voltage in the case of a stalled or broken motor, or a stuck valve. This would then erroneously be considered the region below VO or above V9, and trigger the controller to determine that it has reached either of those regions.

Therefore, it is preferred to use slots that are smaller than the width of the receiver aperture of the optical transceiver, there is no need to use time as a method for determining if the encoder has reached either of those voltage regions. The only way the detected voltage can be below VO or above V9 is if those regions have been reached.

Therefore the possibility of erroneously detecting either of those regions due to a stalled or broken motor, or stuck valve is removed.

Figure 4B shows the example waveforms when a valve having more than one end-stop section is used (eg a diverter valve, discussed later). The minimum voltage corresponds with the reference position and the maxima correspond with end-stop locations. As with figure 4A, the top graph shows the situation where the slot width and the distance between each slot are with the preferred range. The bottom graph shows the situation where the slot widths and distance between each slot are outside of the preferred range.

In order for the controller to know where the valve is (for example when first turned on), it first initialises by driving the valve to the reference position by moving it in the direction of the reference location until this position is indicated as being reached by the encoder. As the controller knows which direction the valve is turning (by virtue of controlling the motor appropriately), the controller may then move to other positions by incrementing or decrementing a counter each time a slot 32 is passed until a desired position is reached. This method saves on component count and complexity since a low processing power microcontroller can be used to control the position of a motor rather than one with higher processing power.

As explained above, there is also no need for a quadrature detector at the output shaft of the motor itself due to the direction already known since it is determined by the controller driving the motor in a particular direction. In the situation where an a quadrature detector was used at the output of a motor shaft, such a system would require a higher processing power microcontroller due to the high number of that would be produced by the motor.

To implement the divert functionality using this method, the controller is preferably pre-programmed to know how many end-stop portions (ie completely open slots) it must encounter before reaching the final end-stop location, otherwise it will not know when to stop moving the valve and therefore risks destroying the mechanism.

Additionally, the controller may determine sub-positions between each defined maximum and minimum given by a slot 32 as is passes through the optical encoder.

Figure 4C shows an example waveform showing one slot position divided into a plurality of sub-positions. The waveform is split into sections by the controller, allowing it to provide more locations at which it can stop, which increases the resolution of control. This can be done if there is a need to increase the resolution to improve the flow control.

The figure shows various voltage points with which the controller may uses to make positioning decisions. The reference position is the voltage point VO and below, and the end-stop voltage points are V9 and above. The positioning voltage regions are below Vi but above VO, V2-V3, V4-V5, V6-V7, above V8 but below V9. This will give a total of 8 positions per complete slot (four on each side of the slope).

The voltage values between V1-V2, V3-V4, V5-V6, and V7-V8 are ignored since they are used as a buffer between the positioning voltage regions to remove the possibility of voltage spikes or electrical noise generating erroneous position changes when the encoder moves into the region between each positioning region.

Valve Control Figure 5 shows a flow chart of a method of controlling a valve.

The initialisation of the valve comprises the controller determining whether or not the reference end-stop has been reached. Following that step, the controller waits until the valve is activated. Once it has determined that the motor is activated, the valve is driven to the reference position if the valve is to be switched off If another position is required, then the controller compares the current position of the valve against the required position of the valve, and drives the motor in an appropriate direction until the desired position is reached. Upon reaching the desired position, the motor is stopped (drive removed) and the motor deactivated, which conserves power.

In preferred embodiments, the valves are substantial enough that once driven into position, they do not require any further holding to retain their position.

Encoder Wheel detectiom Figure 6 shows a flow chart of a method of detecting the encoder wheel position.

Alternative Valve Connection Figure 7 shows an alternative embodiment where the fluid regulator comprises a coupler 74 to couple the output of the motor 2 (or gearbox, where appropriate) to the drive stem 8 of the valve 4. In such an embodiment, the position detector 6 is located on the side of the coupler 74 adjacent to the drive stem 8 of the valve 4.

Water Regulation Device Figure 8 shows an embodiment of a water regulation device that utilises a fluid regulation device of the present invention. In its most basic form, the water regulation device comprises two fluid regulation devices coupled to one another and controlled by a controller in accordance with user-input data and the positional data provided by position detectors.

The device comprises a water mixing section for regulating the temperature of water output from the device, and a water flow section regulating the flow and direction of water output from the device. As with the fluid regulating device, the water regulation device has been designed to utilise the single optical encoder and control system as described above.

The mixing and flow valves are preferably housed in a casting which allows water to enter the temperature mixing valve (via hot and cold water input ports) and then output to the flow valve, which then outputs the water to one of two possible outputs.

(Alternative embodiments may comprise more inputs and/or more outputs).

Hot water and cold water enter their respective input ports and into the temperature mixing valve. The position of the mixer valve regulates the relative mix of hot and cold water output by the valve. A user enters input temperature data (for example via a user interface according to our co-pending application WO 2006/061657) and the controller controls the position of the mixing valve by driving the mixing motor to achieve the desired valve position, which is detected using the position detector as described above.

A temperature monitoring device (for example a thermistor) is positioned in the channel between the mixing and flow valves to provide temperature data to the controller. The controller processes the data to calculate the current temperature and compares it to the desired temperature. The controller then controls the position of the valve to achieve the desired temperature.

Once mixed, the water enters the flow valve, which outputs the water to one of two outputs. The flow rate and which of the outputs used is dependent on the position of the valve. A user enters input flow data (for example via a user interface according to our co-pending application WO 2006/06 1657) and the controller controls the position of the flow valve by driving the flow motor to achieve the desired valve position, which is detected using the position detector as described above.

Temperature control valve operation The mixing valve acts as a temperature control valve in this embodiment by mixing hot and cold water to produce a combined temperature. The end-stops of the encoder wheel for this valve have a fully blocked section for the reference end-stop and a fully open section for the other end-stop.

Figure 9 shows as example output mixture of hot and cold water according to the valve position. As can be seen, from the fully cold position of the valve, the flow rate of cold water increases to a maximum after which the cold water is reduced at the same time as the hot water increased (thus keeping a constant maximum flow) until only hot water is output. At the end-stop position (ie fully open'), the flow rate is in practice slightly reduced from the maximum. The valve is configured to output cold water first as this reduces the risk of a user being scalded with hot water when the valve turns on from its reference position.

When power is first applied to the water regulating device, the controller finds the reference position of the mixing valve by driving the mixing valve in the direction of the reference position until the position is detected using the methods described above.

At this point, the controller turns off the motor to await further commands.

Since the controller has now found the reference position, it can make its location counter equal to zero. It can then keep track of its location as it tracks temperature because it has a reference point from which it can base its location.

Temperature Tracking Figures 1 lA and 11B show methods of performing temperature tracking using the water regulating device.

The temperature tracking is achieved using a thermistor positioned at the output of the point where the hot and cold water have been mixed together. At that point, the thermistor's resistance will change with the temperature and the controller is used to measure the resistance change. Using this value the temperature can be calculated and the controller can then change the mix of hot and cold water according to the measured temperature and the temperature the user requires, as described above.

To change the mix of hot and cold water, the motor is commanded to move a predetermined number of steps according to the difference between the required temperature and the measured temperature. If the temperature difference is great, a large number of steps will be required. If the difference is small, only one step may be required. For example, if the temperature is within 5°C, the valve is moved only one encoder position at a time until the desired temperature is reached. If the difference is greater, then more valve positions, for example 10, may be moved in one go. To minimise the risk of scalding, it is preferred to drive the valve conservatively whchin increasing the temperature than when decreasing the temperature (for example move up steps, but down 10 steps).

Therefore, if the temperature required is greater than that measured, the mix of hot and cold water will be changed to give a warmer mix with more hot water and less cold water. If the temperature required is less than that measured, hot water is reduced and cold water is increased. The controller will then measure the new temperature and continue making decisions as to whether the mix of hot and cold water should change or not.

Scalding Temperature Detection The controller may be designed to detect when the temperature has reached a predetermined temperature, above which is deemed too hot for normal use. When this temperature is detected the controller controls the mixer valve to reduce the hot water amount until it is completely off. If the temperature of the output water does not go below the designated scalding temperature in a predetermined period of time deemed safe, the controller turns off the water flow immediately to stop more water at the scalding temperature being output to the user.

Divert valve operation In an embodiment of the water regulation device, the flow valve is a divert valve. The divert valve used in this embodiment allows the water entering the valve to be output to either of two outputs and control the flow rate of that output. It achieves this by having a centre off position between the two outputs and when it moves to either one of the two outputs, the other stays closed. As it moves into one of the two outputs, it increases the flow rate until it is 10 degrees of rotation away from its end-stop. At this point the valve is fully open at that divert output. It works in the same way for both divert outputs.

Figure 10 shows an example flow output from the diverter valve.

The divert valve has a reference position at one of the fully open end-stops (the reference position on the optical encoder being a fully blocked portion), a first end-stop position (denoted by a fully open portion on the optical encoder) defining the position when the valve is fully closed, and a second end-stop position (denoted by a second fully open portion on the optical encoder) defining the position when the valve is at the second fully open end-stops.

When first powered up, the controller drives the valve to the reference position (if it is not already there), resets any location counters, and then drives the divert valve to the off (mid) position. In this off position, the controller can now be referenced to the real valve off position. The controller is then able to move the divert valve in the correct direction and the correct number of positions for flow rate when commanded by a user through a user input device.

Figures 1 2A and 1 2B show flow charts for implementing diverter algorithms useable with the water regulating device.

Combined motor and valve unit In embodiments, motor and any reduction gearbox can be directly connected to the valve with the output gearbox shaft engineered so that is the main valve stem which the rest of the valve is assembled onto. Therefore there is no need for a coupler, and the encoder wheel including optical sensor and small circuit board will be mounted between the valve body and gearbox body for control purposes. This will allow for a very compact controllable valve for fluid control.

The temperature/mixer unit will have both a hot and cold input which is mixed in a single valve connected to a single motor with a possible additional gearbox. The mixed output of the valve will be directly connected to a thermistor which will measure the temperature of the water. The motor valve unit will be self-contained, incorporating a motor driver, encoder wheel and temperature sensing. The input to the valve unit could be the required temperature, and off selection only. The output from the motor could be the measured temperature. It could also incorporate an initialisation register, which includes the scalding temperature which the unit will address when this occurs.

An equivalent divert valve assembly could also incorporate a motor controller and encoder positioning unit. It could receive positional information only including off position and divert position. There will be feedback to indicate when the valve assembly has reached that position. There can be more than two divert positions if required.

Pressure Independece A difference in pressure between the cold and hot water input affects the temperature tracking mechanism in terms of resolution only. If the pressures are different for the same temperature at other pressures, the position that gives the same temperature will change. The controller is configured to move the mixer valve in the direction required to match the measured temperature with the requested temperature. This is because the valve has full control over how much hot or cold water is allowed in.

Automatic Power Loss Valve Close Mechanism The water regulation device may incorporate an automatic turn off feature when power is lost. This may be accomplished using a power reservoir, such as a bank of capacitors, battery backup, or some other form of energy source not connected to the main energy source. The requirement for this is that if the unit is in use when loss of main power occurs, water is not wasted and the user is not scalded while waiting for main power to be restored.

The controller detects when power is lost by doing a comparison between the main voltage input and an internal one powered by the power reservoir. When the main voltage drops below the reservoir voltage, the controller commands the valves to turn off. The flow valve should have enough power to turn the water flow off.

An additional solenoid valve could also be added to the output of the temperature mixing valve to close off the water flow when power is lost. This solenoid valve would be fully open when energised allowing water to flow and be closed when power has been removed from the solenoid valve. Therefore, when the unit has been turned off by the user or power has been lost, the solenoid valve will lose power and therefore stop the flow of water.

Rechargeable Battery In case of lengthy power loss situations, a large battery can be included in the water regulation unit that allows several hours of normal operation in case of power loss.

Therefore it will still be possible for users to control the water flow when mains power has been lost rather than have to wait for power to be restored or use manual taps to override the electronic control, for as long as the battery can supply power.

When power is restored, the battery is recharged while the water control unit is operating in normal mains powered state and once fully charged, it is simply tricide charged to maintain its full power in the same way as any battery charger operates.

Therefore, when the next power outage happens, the unit will be ready to begin using the battery from the battery's full capacity.

Gearbox Slack Removal Slack in the gearbox is created by having a large number of gears in the gearbox, each with their own tolerance variations to their original design, which is unavoidable in mass production. These tolerances produce small gaps between the connecting teeth between each gear. They add up to produce a large overall tolerance of the gearbox. The more gears used in a gearbox, the larger the potential tolerance and therefore the larger the slack in the gearbox. This slack must be taken up by the turning of the motor before the gearbox transfers the movement from its shaft to the output of the gearbox shaft.

Therefore not only is there a delay in time of movement from when the motor starts turning to when the output shaft of the gearbox starts turning, there is also momentum built up in the gearbox by the time the gearbox output shaft starts turning.

Slack in the gearbox can create positioning errors when using a quadrature detector at the motor shaft end, which does not see the errors in the gearbox. Using absolute positioning at the output shaft of the gearbox, these errors can be mitigated. This is done by running the motor in the direction required at a speed that develops torque lower than that required to get over the inertia of the valve, but more than the inertia to power the gearbox. This can be done until the motor stalls at that very low power input. The errors in the gearbox will have now been removed allowing the real inertia of the valve to now be controlled. This means, all gear teeth will be under load against each other with no distance between each connecting tooth of each gear in the gearbox. Therefore, once extra power is applied above the torque required to move the valve, all power goes directly to the gearbox output shaft, which is directly connected to the shaft of the valve.

This overcomes the problem of momentum generated in the gearbox before the inertia of the valve has been reached. There are two stages. The first stage is that of overcoming the slack in the gearbox. The second stage is overcoming the inertia of the valve. If the slack in the gearbox isn't taken into account, the acceleration in the gearbox will create a momentum, which, once the inertia of the valve has been reached, will immediately force the valve to move with no soft start. Therefore if it is required that the valve only move a minimum radial distance, it will most certainly move past that point before the motor can be turned off This will result in the position it eventually stops at being further than the radial position it was planned to stop at.

Stage one is most useful when the valve must be turned in the opposite direction to which it has just turned. In this case the slack in the gearbox will be at its maximum for turning in the opposite direction. In order to guarantee correct positioning of the valve, stage one must be performed in the new direction of rotation before stage two, that of moving the valve itself Using Valve Inertia as a Brake In order to simplify the electronics and also protect the electronics, the use of a braking system is not required. By utilising the inherent inertia of the valve itself, once the required location of the valve had been reached, by removing power from the motor the torque required by the valve to turn it becomes greater than that supplied to the motor.

The valve will then stop turning and maintain its position. This reduces wear on the motor since it is not forced to stop moving by a brake or forced to stop moving by immediately changing its direction, both of which could result in powerful electrical spikes in the motor and control circuitry potentially destroying either or both.

No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the scope of the claims appended hereto.

Claims

CLAIMS: 1. A fluid regulation device for regulating the flow of fluid through a valve, comprising: a valve having one or more input ports for receiving fluid, and one or more output ports for outputting fluid, and a drive stem for driving the valve; a motor coupled to the drive stem of the valve to drive the valve to regulate a flow of fluid between the one or more input ports and the one or more output ports; a controller for controlling the motor in response to a desired flow of fluid through the valve; and a position detector for detecting the position of the valve, the position detector being coupled to the drive stem of the valve, wherein the position detector is configured to output a first position signal dependent on a first detected position of the valve, and a second position signal, different from the first position signal, depending on a detected reference position of the valve, and wherein the controller controls the motor to drive the valve to a desired position in response to the first and second position signals to regulate the flow of a fluid flowing through the valve.
2. A device according to claim 1, wherein the position detector comprises an optical encoder having an encoder portion defining a plurality of positions, each of the plurality of positions corresponding to a partially-open position of the valve, and the encoder outputting the first position signal for each of the positions; and wherein the optical encoder is coupled to the valve stein such that a change in the valve position corresponds to a change in encoder positions.
3. A device according to claim 2, wherein the encoder comprises a reference encoder portion defining a reference position of the encoder that corresponds to the reference position of the valve; and wherein the encoder outputs the second position signal when the valve is in the reference position.
4. A device according to claim 3, wherein the reference position of the valve corresponds to the valve being substantially fully closed.
5. A device according to claim 2, 3 or 4, wherein the encoder comprises an end-stop encoder portion defining an end-stop position that corresponds to an end-stop position of the valve; and wherein the encoder outputs a third position signal, different from the first and second position signals, when the valve is at the end-stop position.
6. A device according to claim 5, wherein the end-stop position of the valve corresponds to the valve being substantially fully open.
7. A device according to any one of claims 2 to 6, wherein the encoder portion comprises a plurality of equally-spaced apertures to allow light to pass theretbrough, each aperture defining an encoder position, and each aperture having a width of less than or equal to the width of a receiving aperture of an optical sensor comprising the optical encoder.
8. A device according to claim 7, wherein the first position signal comprises a substantially sinusoidal or triangular signal when the valve is moved from a first position to the next position.
9. A device according to claim 8, wherein the controller processes the first position signal to determine a plurality of sub-positions between a first position and the next position, to which the valve is drivable, by comparing a detected portion of the first signal against a plurality of threshold levels.
10. A device according to any one of claims 3 to 9, wherein the reference portion comprises a blocking portion that prevents light passing therethrough, and having a width that is greater than the width of a receiving aperture of an optical sensor comprising the optical encoder.
11. A device according to any one of claims 5 to 10, wherein the end-stop portion comprises an aperture to allow light to pass therethrough, the aperture having a width that is greater than a receiving aperture of an optical sensor comprising the optical encoder.
12. A device according to any preceding claim, comprising a coupler to couple the motor to the drive stem of the valve, and wherein the encoder is mounted on a portion of the coupler adjacent the drive stem of the valve.
13. A device according to any preceding claim, wherein the motor comprises a gearbox for reducing the number of output revolutions of the motor and for increasing the torque of the motor.
14. A water regulation device for regulating the temperature and flow of water, comprising: a mixing valve for regulating the temperature of water, the mixing valve having a hot water input port for receiving hot water, a cold water input port for receiving cold water, a mixer output port for outputting a mixture of the input hot and cold water, and a drive stem for driving the valve; a flow valve for regulating the flow of water, the flow valve having an input port coupled to the output port of the mixing valve, one ore more output ports for outputting a regulated mixture of water, and a drive stem for driving the valve; a mixer motor coupled to the drive stem of the mixing valve to drive the mixing valve to regulate a temperature of the water output from the mixing valve, and a flow motor coupled to the drive stem of the flow valve to drive the flow valve to regulate a flow of water output from the device; a controller for controlling each of the motors in response to a desired temperature and flow of water through the device; a mixing valve position detector for detecting the position of the mixing valve, the mixing valve position detector being coupled to the drive stem of the mixing valve; and a flow valve position detector for detecting the position of the flow valve, the flow valve position detector being coupled to the drive stem of the flow valve, wherein each of the position detectors is configured to output a first position signal dependent on a first detected position of the respective valve to which the position detector is coupled, and a second position signal, different from the first position signal, depending on a detected reference position of the respective valve to which the position detector is coupled, and wherein the controller controls the mixer motor to drive the mixer valve to a desired position in response to the first and second mixing valve position signals to regulate the temperature of the water flowing through the device, and wherein the controller controls the flow motor to drive the flow valve to a desired position in response to the first and second flow valve position signals to regulate the flow of the water the device.
15. A device according to claim 14, wherein each of the position detectors comprise an optical encoder having an encoder portion defining a plurality of positions, each of the plurality of positions corresponding to a partially-open position of the respective valve to which the encoder is coupled, and the encoder outputting the first position signal for each of the positions; and wherein each of the optical encoders is coupled to the respective valve stem such that a change in the respective valve position corresponds to a change in respective encoder positions.
16. A device according to claim 15, wherein each of the encoders comprise a reference encoder portion defining a reference position of the encoder that corresponds to the reference position of the respective valve to which the encoder is coupled; and wherein the encoder outputs the second position signal when the respective valve is in the reference position.
17. A device according to claim 15 or 16, wherein each of the encoders comprise an end-stop encoder portion defining an end-stop position that corresponds to an end-stop position of the respective valve to which the encoder is coupled; and wherein the encoder outputs a third position signal, different from the first and second position signals, when the respective valve is at the end-stop position.
18. A device according to claim 17, wherein the encoder of the flow valve position detector comprises a second end-stop encoder portion defining a second end-stop position that corresponds to a second end-stop position of the flow valve; and wherein the encoder outputs a third position signal when the flow valve is at the second end-stop position.
19. A device according to any one of claims 15 to 18, wherein the encoder portion comprises a plurality of equally-spaced apertures to allow light to pass therethrough, each aperture defining an encoder position, and each aperture having a width of less than or equal to the width of a receiving aperture of an optical sensor comprising the optical encoder.
20. A device according to claim 19, wherein the first position signal comprises a substantially sinusoidal or triangular signal when the valve is moved from a first position to the next position.
21. A device according to claim 19, wherein the controller processes the first position signal to determine a plurality of sub-positions between a first position and the next position, to which the valve is drivable, by comparing a detected portion of the first signal against a plurality of threshold levels.
22. A device according to any one of claims 16 to 21, wherein the reference portion comprises a blocking portion that prevents light passing therethrough, and having a width that is greater than the width of a receiving aperture of an optical sensor comprising the optical encoder.
23. A device according to any one of claims 17 to 22, wherein the end-stop portion comprises an aperture to allow light to pass therethrough, the aperture having a width that is greater than a receiving aperture of an optical sensor comprising the optical encoder.
24. A device according to any one of claims 14 to 23, comprising a coupler to couple the respective motors to the drive stem of the respective valves, and wherein the respective encoder is mounted on a portion of the respective coupler adjacent to the drive stem of the respective valve.
25. A device according to any one of claims 14 to 24, wherein each of the motors comprise a gearbox for reducing the number of output revolutions of the motor and for increasing the torque of the motor.
26. A device according to any one of claims 14 to 25, comprising a temperature sensor to detect a temperature of a mixture of water output from the mixing valve.
27. A device according to claim 26, wherein the controller is configured to receive user input temperature data setting a desired temperature of the water output from the device, and is configured to control the mixer motor to drive the mixer valve in response to the first and second position signals, the user input temperature data and the detected temperature of the mixed water such that the temperature of the water output from the device is substantially equal to the desired temperature.
28. A device according to any one of claims 14 to 27, wherein the controller is configured to receive user input flow data setting a desired flow of the water output from the device, and is configured to control the flow motor to drive the flow valve in response to the first and second position signals and the user flow data such that the flow of the water output from the device is substantially equal to the desired flow.
29. A device according to any one of claims 14 to 28, wherein the flow valve is a divert valve having at least two outputs and for diverting a flow of water to one of the at least two outputs.
30. A device according to claim 29, wherein a first divert valve output is coupleable to a shower unit, and a second divert valve output is coupleable to a bath unit.