GB2538174A

GB2538174A - Water boiler

Info

Publication number: GB2538174A
Application number: GB1609710.7A
Authority: GB
Inventors: Richard Jackson Andrew
Original assignee: Lincat Ltd
Current assignee: Lincat Ltd
Priority date: 2016-06-03
Filing date: 2016-06-03
Publication date: 2016-11-09
Anticipated expiration: 2036-06-03
Also published as: GB2538174B; GB201609710D0

Abstract

A water boiler with a heating element 2 for heating water in a tank 1. An inlet valve controls the flow of water through the inlet 3 into the tank. An outlet valve controls the flow of water through the outlet 4 out of the tank. Sensing means monitor a parameter related to the water. A controller, linked to the sensing means, determines a dispensing rate of water from the tank using the sensing means, and automatically maintains the water in the tank at a first level, when the dispensing rate is at or below a first predetermined rate, and at a second higher level, when the dispensing rate is at or above a second predetermined rate. Optionally the sensing means comprises a float, a pressure sensor, a weight sensor, an optical sensor or one or more proximity sensors. Optionally, there is further provided a level sensor 5 that may have a plurality of spaced apart electrically conductive probes, 5a, 5b, 5c. One of the probes 5a may be provided at the first level and a second of the probes 5b may be provided at the second level.

Description

Water boiler The present disclosure relates to a water boiler, in particular to an energy efficient water boiler that automatically varies the volume of hot water stored in a tank, by varying the refill level of the tank, in dependence on the dispensing rate of hot water from the tank.

Water boilers are well known, they are used to provide a ready supply of hot water, typically at a temperature slightly below boiling point, for use to make hot drinks or otherwise. They generally comprise a tank for storing water to be dispensed, a heating element for heating the water in the tank and an outlet through which the hot water may be selectively dispensed.

Automatic fill water boilers are connected to a water supply and are provided 15 with water level sensing means, whereby the volume of water in the tank may be maintained at a predetermined (full/top) level at a desired temperature.

An exemplary conventional automatic fill water boiler has a pair of level sensors to control the water level. On start-up, from empty, cold water fills to a low level sensor and is then heated to boiling point (or a temperature slightly below boiling point) before the tank is automatically filled and heated in a controlled manner to the level of a top level sensor. As water is drawn off and the top level sensor is no longer in the water more cold water is added and heated. The water is perpetually maintained at the top level at the desired temperature.

This arrangement suffers from the drawback that when demand is low there is an excess of water maintained around boiling point. The present invention arose in a bid to provide a more energy efficient water boiler.

According to the present invention in a first aspect, there is provided a water boiler comprising: a tank; a heating element for heating water in the tank; an inlet through which the tank is filled, and an inlet valve controlling the flow of water through the inlet; an outlet through which water is dispensed from the tank, and an outlet valve controlling the flow of water through the outlet; sensing means for monitoring a parameter related to the water; and a controller, which is linked to the sensing means, and is arranged to determine a dispensing rate of water from the tank using an output of the sensing means and to automatically maintain the quantity of the water in the tank at a first level, when the dispensing rate is at or below a first predetermined rate, and at a second higher level, when the dispensing rate is at or above a second predetermined rate.

Further, preferred, features are presented in the dependent claims.

Non-limiting embodiments will now be described, by way of example only, with reference to the accompanying drawing, Figure 1, which shows a perspective view of the water tank of a water boiler according to the present invention.

The tank 1 will be mounted within a suitable housing (not shown), which may take any conventional form, to complete the water boiler. The water boiler may be freestanding for placement on a counter top or otherwise, or may be wall mountable. The housing will be configured accordingly. Whilst the tank is shown to be open at the top, it will preferably be closed in use.

The water boiler further comprises a heating element 2 for heating water in the tank 1, an inlet 3 through which the tank is filled and an outlet 4 through which water is dispensed from the tank 1. The heating element may take any conventional form. It is electrically powered. An inlet valve (not shown) is provided for controlling the flow of water into the tank through the inlet 3 and an outlet valve (not shown) is provided for controlling the flow of water out of the tank through the outlet 4. The inlet 3 is connected to a substantially continuous supply of water. It is most preferably plumbed in to a mains water supply.

A sensing means (not shown) is provided for monitoring a parameter related to the water. A controller (not shown) is provided, which controls the inlet valve.

Control of the inlet valve by the controller occurs in dependence on a determined dispensing rate. The controller is arranged to determine the dispensing rate of water from the tank using an output of the sensing means. Specifically, the controller operates to automatically maintain the quantity of the water in the tank at a first level when the dispensing rate is at or below a first predetermined rate, and at a second higher level when the dispensing rate is at or above a second predetermined rate.

The operation mode in which the quantity of water is maintained at the first, lower, level may be considered to be an Economy (Eco) mode and the operation mode in which the water is maintained at the second, higher, level may be considered to be a conventional (full tank) operation mode. In accordance with the present invention the Eco mode is automatically switched on/off in dependence on the dispensing rate of water from the water tank.

By such an arrangement the energy efficiency of the water boiler may be increased. When demand for hot water is low, the volume of stored water, which is maintained at a desired temperature (at or around boiling point), is reduced. The reduction occurring by the automatic control of the refill level. The required energy for maintaining a smaller volume of water at temperature is less and the environmental impact of the water boiler is thereby reduced.

It should be appreciated that in dependence on the sensing means implemented, as will become clear from the discussion below, the water quantity in the Eco mode may be set at one or more predetermined levels or may be continuously variable with the refill level of water in the Eco mode continuously varied in dependence on continuously monitored demand.

Considering the exemplary arrangement of Figure 1, the sensing means comprises the inlet valve. The sensed parameter relating to the water is the flow of water into the tank. The open time of the valve is measured to calculate the flow of water into the tank.

By measuring the flow of water into the tank, the volume of water introduced into the tank may be calculated. The volume of water introduced into the tank equates to the volume of water dispensed from the tank. This is because, in dependence on the operation mode, the water boiler maintains the water level at either the first or second level at all times. When water is drawn off from the tank and the water level drops from the first or second level, water is automatically added to return the water level to the first or second level. The volume of water added equals the volume of water drawn off. The volume of water drawn off in a given time equals the dispensing rate.

The controller receives information regarding the flow of water into the tank from the inlet valve. The inlet valve comprises a solenoid controlled valve that has a flow regulator. It may have a predetermined constant flow rate. As will be appreciated by those skilled in the art, alternative forms of electronically controlled flow valves may also be used.

It should be appreciated that whilst the solenoid controlled valve comprising the sensing means is provided at the inlet, it could additionally or alternatively be provided at the outlet such that the measurement occurs there also or instead. Furthermore, a dedicated flow sensor could be provided for use as the sensing means in place of the valve itself at either the inlet or outlet.

The controller receives information regarding the level of water in the tank from the level sensor 5, which information is used to control refilling. The level sensor in the present arrangement comprises three electrically conductive probes 5a, 5b, 5c, which are vertically spaced from one another along the inner wall of the tank. A first of the probes 5a is provided at the first level, a second of the probes is provided vertically above the first probe 5b at the second level and the third probe Sc is provided vertically below the first probe. The third probe 5c measures a low level of water in the tank, the first probe 5a measures a mid-level of water in the tank (for use in the Eco operation mode) and the second probe 5b measures a top level of water in the tank (for use in the full tank operation mode).

It should be appreciated that whilst there are three probes provided in the present arrangement, in alternative arrangements there may be multiple vertically spaced probes between the low level probe Sc and the top level probe 5b to allow for the provision of a range of intermediate fill levels between the low and full levels.

Considering the typical operation of this arrangement: On start-up, from empty, cold water fills to the level of the low level sensor (measured by the third probe 5c) and is then heated to a predetermined temperature, which is typically boiling point or a temperature slightly below boiling point, say 94 to 98°C, before the tank is automatically filled and heated in a controlled manner to the level of the top level sensor (measured by the second probe 5b) such that the tank is full. The water is maintained at the predetermined temperature under the control of the controller by suitable use of the heating element. As water is drawn off and the top level sensor is no longer in the water, the controller determines that more water must be added to the tank through the inlet valve to maintain the water at the top level. The controller instructs the opening of the inlet valve and more water is added and heated. However, as discussed, information regarding the dispensing rate of water from the tank is determined by the controller on the basis of the information from the inlet valve to allow for the automatic activation of the Eco mode.

If it is determined that the dispensing rate is at or below the first predetermined rate then Eco mode is automatically activated and the level of water in the tank will be allowed to drop to the level of the first probe 5a, which is provided at a mid-level between the third and first probes. The volume of water maintained at the predetermined temperature is then maintained at this level until such time as the demand for heated water increases to the point that the dispensing rate is determined to be at or above the second predetermined rate, wherein Eco mode will be automatically switched off and the conventional (full tank) operation mode will be re-implemented. The volume of water at the predetermined temperature will be maintained at the level of the second probe 5b.

The automatic switching back and forth between Eco mode and full-tank mode will occur in dependence on the measured dispensing rate.

The controller may comprise a processor that runs software that may be adapted to suit different tank sizes and demands and any additional variables. The user controls of the water boiler may comprise a touch screen or an array of buttons, as will be appreciated by those skilled in the art.

As an example, based on the arrangement of Figure 1, the software may comprise an algorithm that controls the automatic switching between the conventional (full tank) mode of operation and the Eco mode of operation wherein the switch between modes occurs in dependence on the rate of dispensing, calculated as follows: 1 If the inlet valve solenoid is on for less than n minutes in a predefined period, operation of the water boiler is switched to Eco mode; and 2. If the inlet valve solenoid is on for more than n minutes in a predefined period, operation of the water boiler is switched to full tank mode.

In an example, the Eco mode may be automatically switched on when the dispensing rate of water is less than 5 litres per hour and automatically switched off 15 when the dispensing rate is more than 5 litres per hour, with these rates determined on the basis of the open time of the inlet valve within a period.

As discussed, the settings may be varied as desired in dependence on the tank size, location and likely use of the water boiler, etc. There may be a number of user selectable presets Whilst in the above arrangement, the water boiler starts in full tank mode, it is possible that the water boiler is set to start in Eco mode, or to learn about demand over time (by logging usage profiles or otherwise) and automatically adapt to suit common usage patterns, from start up or otherwise. Clearly, if the water boiler is started in Eco mode, or Eco mode is user activated shortly after the powering up of the water boiler, then the water will only fill to the first level on start up and will only be automatically switched out of Eco mode when the dispensing rate is at the second level or higher. It is preferable that the water boiler is configured to always start in full tank mode and to automatically switch to Eco mode in dependence on demand. It is preferable that powering down of the water boiler will reset its operation, such that on start-up it will always enter full tank mode.

It may be possible that the automatic switching on/off of Eco mode is a user selected option, wherein it may be disabled by a user. In this case a user may select full tank or Eco mode as an always on option.

In the above arrangement the sensing means comprises the inlet (and/or outlet valve). A separate level sensor is provided for detecting the fill level. The level sensing means described above, which comprises multiple probes at different levels, detects the fill level of the water tank in a binary rather than variable manner. The first and second levels are fixed by the levels of the probes 5a, 5b. It should be appreciated that alternative level sensors may be implemented in the above arrangement, in addition to the flow sensing means, that allow for variable sensing of the water level (not just at predetermined levels). With such an arrangement both the first and second levels may be varied in dependence on dispensing rates. Alternative sensing means may detect the water level directly or indirectly and include, but are not limited to: a float valve, a flow sensor, a proximity sensor, a pressure sensor, a weight sensor, an ultrasonic sensor, an optical sensor, a capacitive-inductive sensor, or a sensor for calculating the water added to the tank by the amount of the heat input.

In further alternative arrangements, an alternative sensing means may be implemented that obviates the need for separate level and flow sensing means, in the manner of the above arrangements. As will be appreciated by those skilled in the art, in any arrangement where the level of water in the tank may be continuously monitored, directly or indirectly, by a sensing means such that the specific level of water in the tank is known (in a variable rather than binary manner), that sensing means may be used alone for automatically controlling the switching on/off and/or operation of the Eco mode. Moreover, that sensing means may allow for the level of water in in Eco mode to be continuously varied across a large variable range of levels in dependence on the real time dispensing rate of water from the water tank.

That is there could be multiple, variable, first levels set below the second (full tank level) and above the low tank level. Moreover, the first and second levels could both be variable.

Suitable alternative sensing means in this context again include, but are not limited to: a float valve, a flow sensor, a proximity sensor, a pressure sensor, a weight sensor, an ultrasonic sensor, an optical sensor, a capacitive-inductive sensor, or a sensor for calculating the water added to the tank by the amount of the heat input.

With any of these sensors, as will be appreciated by those skilled in the art, it will be possible to determine dispensing rate whilst also knowing the specific level of water in the tank. For example, a float valve may continuously monitor the water level of the tank, wherein any reduction in the level as measured against time will provide the dispensing rate. In a further example, flow sensors at the inlet and outlet would provide a means of monitoring the level of water in the tank and the rate of dispensing. Countless alternative arrangements further exist, as will be appreciated by those skilled in the art.

Claims

Claims 1. A water boiler comprising: a tank; a heating element for heating water in the tank; an inlet through which the tank is filled, and an inlet valve controlling the flow of water through the inlet; an outlet through which water is dispensed from the tank, and an outlet valve controlling the flow of water through the outlet; sensing means for monitoring a parameter related to the water; and a controller, which is linked to the sensing means, and is arranged to determine a dispensing rate of water from the tank using an output of the sensing means and to automatically maintain the quantity of the water in the tank at a first level, when the dispensing rate is at or below a first predetermined rate, and at a second higher level, when the dispensing rate is at or above a second predetermined rate.
2. A water boiler as claimed in Claim 1, wherein the parameter related to the water comprises one or more of the level of the water in the tank, the flow of water into or out of the tank, an open time of the inlet and/or outlet valve, the temperature of the water, the weight of the water, an outlet pressure, or heat energy added to the water.
3. A water boiler as claimed in any preceding claim, wherein the inlet valve and/or the outlet valve comprises the sensing means.
4. A water boiler as claimed in Claim 3, wherein the inlet valve and/or the outlet valve comprises a constant flow rate valve.
5. A water boiler as claimed in Claim 3 or 4, wherein the inlet valve and/or the outlet valve comprises a solenoid controlled valve.
6. A water boiler as claimed in any of Claims 3 to 5, wherein the controller is arranged to monitor the opening of the inlet valve and/or the outlet valve against time.
7. A water boiler as claimed in Claim 1 or 2, wherein the sensing means comprises a float, a pressure sensor, a weight sensor, an optical sensor or one or more proximity sensors.
8. A water boiler as claimed in any preceding claim further comprising a level 10 sensor.
9. A water boiler as claimed in Claim 8, wherein the level sensor comprises a float, a pressure sensor, a weight sensor, one or more electrically conductive probes, an optical sensor or one or more proximity sensors.
10. A water boiler as claimed in Claim 8 or 9, wherein the level sensor comprises a plurality of electrically conductive probes, which are spaced from one another, a first of the probes being provided at the first level and a second of the probes being provided at the second level.
11. A water boiler as claimed in Claim 10, wherein a third probe is provided at a level below the first level for sensing a low level of water in the tank.
12. A water boiler as claimed in Claim 11, wherein there are a plurality of first 25 probes spaced from one another at different levels between the second and third probes.
13. A water boiler as hereinbefore described with reference to Figure 1.