WO2004041729A1

WO2004041729A1 - Electronic de-scalers

Info

Publication number: WO2004041729A1
Application number: PCT/GB2003/004802
Authority: WO
Inventors: Michael Gott
Original assignee: Hotta Uk Limited
Priority date: 2002-11-07
Filing date: 2003-11-05
Publication date: 2004-05-21
Also published as: GB0225981D0; AU2003301856A1; GB2395193A; GB2395193B

Abstract

The present invention provides an electronic de-scaler for treating a volume of water. The electronic de-scaler includes an electrically conductive coil (2) which is connected to a signal waveform generator (8). The signal waveform generator (8) output a variable signal waveform to the electrically conductive coil (2). The signal waveform generator (8) is mounted on a printed circuit board (4) along with a battery (10) and a temperature sensor (12). The temperature sensor (12) automatically controls when the signal waveform generator (8) outputs the variable signal waveform to the electrically conductive coil (2). The electrically conductive coil (2), signal waveform generator (8), the battery (10) and the sensor (12) are enclosed within a waterproof housing (16) such that the electronic de-scaler is freely submergible in the volume of water.

Description

TITLE

Electronic De-scalers

DESCRIPTION Technical Field

The present invention relates to electronic de-scalers, and in particular to electronic de-scalers for treating hard water in an energy efficient manner.

Background Art Certain areas of the country suffer from "hard water" where large concentrations of calcium and magnesium ions are dissolved in the domestic water supply. One of the main problems with hard water is that the calcium and magnesium ions are eventually deposited as limescale which coats the heating elements of kettles and other water- heating units and reduces their efficiency. It is therefore necessary to de-scale such appliances on a regular basis using chemicals that attack and dissolve the limescale deposits.

It is possible to treat hard water using a conventional electronic de-scaler. In a conventional electronic de-scaler a wire coil is tightly wrapped around a pipe through which the hard water is then supplied. A signal waveform generator is used to generate a signal waveform that is outputted to the wire coil. The frequency of the signal waveform is continuously modulated while the hard water is passed through the pipe. The signal waveform produces a varying electromagnetic field in the wire coil that changes the chemical and physical properties of the calcium and magnesium ions to remain in solution. These changes are thought to be brought about by Lorentz forces acting on the charged calcium and magnesium ions moving through the electromagnetic field.

An example of a conventional electronic de-scaler is disclosed in United States Patent No. 5,738,766 entitled "Device for neutralizing and preventing formation of scale and method". The device includes an electromagnetic coil 14 which is wrapped around the outside of a water conduit 12. A power supply for the coil 14 generates a complex triangular waveform output signal that varies continuously in frequency and amplitude. The output signal is applied across the coil 14 to create a varying electromagnetic field to treat the water flowing in the conduit 12.

The calcium and magnesium ions typically stay in solution for between 4 and 7 days if the treated water remains at room temperature. However, if the treated water is subsequently heated then the calcium and magnesium ions no longer remain in solution and are deposited as limescale. The problem is particularly acute when the treated water is boiled.

There is a problem with the versatility of conventional de-scalers because they can only be used in situations where the wire coil is tightly wrapped around a pipe through which the hard water is then passed. Conventional de-scalers are therefore unable to be used to prevent limescale from coating the heating elements of kettles that are filled with hard water directly from the tap. The invention seeks to provide a solution to this problem by not requiring the electromagnetic field to be applied using a coil wrapped around the outside of a pipe through which hard water flows. Desirably the water treatment should be effective when applied to a volume of water in a reservoir of a water-heating unit: Such a treatment would be a departure from all known conventional teachings.

Summary of the Invention

The present invention provides an electronic de-scaler for treating a volume of water comprising an electrically conductive coil, a signal waveform generator connected to the electrically conductive coil for outputting to the electrically conductive coil a variable signal waveform, a power source, and a sensor for automatically controlling when the signal waveform generator outputs the variable signal waveform to the electrically conductive coil, wherein the electrically conductive coil, the power source, the signal waveform generator and the sensor are enclosed within a waterproof housing such that the electronic de-scaler is freely submergible in the volume of water. The electronic de-scaler can be placed directly in the water to be treated. Although such an arrangement would appear to turn directly away from conventional teaching which requires the water to flow through a pipe, the inventors have found surprisingly that the treatment is still effective.

The electronic de-scaler can be used to treat water stored in the reservoir of a water- heating unit. The water-heating unit can be a kettle or hot water dispenser such as a domestic or hot water boiler or a BOILING POINT™ dispenser sold by the present applicant. The water-heating unit can also be a washing machine or a dishwasher, both of which usually have to heat water to a suitable temperature before the water can be used. The water-heating unit can also be a steam-generating unit such as, for example, the steam supply of a commercial coffee machine, a vending machine of the kind which dispenses hot drinks such as tea, coffee and hot chocolate, or the steam supply of industrial laundry irons and steamers.

However, the electronic de-scaler can also be used to treat water stored in a reservoir and which is not heated. The reservoir can be the cistern of a toilet or a domestic cold water tank, for example.

The sensor is responsive to one or more external conditions that can be used to switch the electronic de-scaler on and/or off automatically. The condition(s) can include a physical property of the water to be treated such as its temperature, or an operating condition of the electronic de-scaler itself such as its movement or position within the volume of water to be treated. The condition(s) can also include the pressure within a sealed reservoir or ambient sound. The use of a sensor avoids the need to switch the electronic de-scaler on and off manually. It also means that the electronic de-scaler is extremely energy efficient because the water is only treated on an intermittent basis.

The sensor can be a temperature sensor such as an electronic temperature sensor of known type. In this case the signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil when the temperature of the water to be treated rises above a predetermined level. The inventors have discovered that the de-scaling treatment is particularly effective if it is carried out before the temperature of the water rises above 68°C.

The signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil in response to a predetermined change in the temperature of the water to be treated. For example, the signal waveform generator can start to output the variable signal waveform to the electrically conductive coil when the temperature of the water rises by a predetermined amount in a predetermined period of time. The inventors have found that good results are obtained if the signal waveform generator starts to output the variable signal waveform when the temperature sensor detects that the temperature of the water has risen by 3°C within a time period of 15 seconds.

The sensor can be a movement sensor such as a tilt switch of known type. In this case the signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil when the movement of the electronic de-scaler in the volume of water rises above a predetermined level. The inventors have found that the predetermined level can be set at a certain number of 180° flips, for example. Good results have been obtained if the signal waveform generator starts to output the variable signal waveform to the electrically conductive coil when the movement sensor detects that the electronic de-scaler has made five 180° flips within a time period of 15 seconds.

It will be readily appreciated that if the electronic de-scaler is placed in the reservoir of a water-heating unit then the convection currents formed as the water is heated will cause the electronic de-scaler to move around in the water in a tumbling action. The movement of the electronic de-scaler helps to make sure that all of the water in the reservoir is properly treated. It is also postulated that the convection currents may assist in the treatment process by generating Lorentz forces which act on the charged calcium and magnesium ions moving through the electromagnetic field. It will also be readily appreciated that if the electronic de-scaler is placed in a toilet cistern then the flow currents formed as the cistern is drained and refilled when the toilet is flushed will cause the electronic de-scaler to move around in the water in a tumbling action. Similar flow currents are formed when water is taken from a domestic cold water tank and the tank is refilled from the mains supply. If the sensor is a movement sensor then the signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil every time the toilet is flushed or water is taken from the domestic cold water tank. This ensures that the hard water used to refill the toilet cistern or domestic cold water tank is treated immediately.

The sensor can be an acoustic sensor of known type. In this case the signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil when the ambient sound detected by the sensor rises above a predetermined level. It will be readily appreciated that if the electronic de-scaler is placed in the reservoir of a water-heating unit then the sound within the reservoir will increase as the water is heated. Once the sound reaches a certain level of intensity then the signal waveform generator can be automatically controlled to start to output the variable signal waveform to treat the water.

Sound is also important if the electronic de-scaler is placed in a toilet cistern, for example. It will be readily appreciated that when a toilet is flushed it creates a considerable amount of noise. If the sensor is an acoustic sensor then the signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil every time the toilet is flushed.

The acoustic sensor can be configured to detect only ambient sounds within a certain range of frequencies, or having certain frequency characteristics. For example, if the electronic de-scaler is placed in a toilet cistern then the acoustic sensor can be configured to detect only the sound produced when the toilet is flushed. If the water-heating unit is a steam-generating unit such as the steam supply for industrial laundry irons and steamers then the water is normally kept at boiling point. However, the pressure within a sealed reservoir of the steam-generating unit can vary quite considerably when the irons and steamers are being used. In this case the sensor can be a pressure sensor of known type and the signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil when the pressure in the sealed reservoir of the steam- generating unit rises above a predetermined level.

The sensor can be a proximity sensor. In this case the signal waveform generator can be automatically controlled to start to output the variable signal waveform to the electrically conductive coil when the electronic de-scaler is less than a predetermined distance from a surface or trigger device. The inventors have appreciated that the electrically conductive coil can be used to sense how far the electronic de-scaler is from a surface using capacitative and/or inductive effects. For example, if the electronic de-scaler is placed in a toilet cistern then when the toilet is flushed the water level in the cistern will drop and the electronic de-scaler will move towards the bottom surface of the cistern. This movement can be sensed by measuring changes in the capacitance and/or inductance of the electrically conductive coil. If the electronic de-scaler comes into proximity with the bottom surface of the toilet cistern then the signal waveform generator can be made to start to output the variable signal waveform to the electrically conductive coil so that the water flowing into the cistern is treated immediately.

The proximity sensor can be a magnetic reed switch which automatically controls the signal waveform generator start to output the variable signal waveform to the electrically conductive coil when it comes into proximity with a trigger device such as a permanent magnet.

The electronic de-scaler can include two or more identical or different sensors depending on its intended use. For example, an electronic de-scaler for use in a toilet cistern could include a movement sensor and an acoustic sensor. The signal waveform generator can be made to output the variable signal waveform for a predetermined amount of time. The inventors have found that treating the water for approximately 2 to 2V_ minutes produces good results. The sensor can also automatically control the signal waveform generator to stop outputting the variable signal waveform to the electrically conductive coil. For example, if the sensor is a temperature sensor then it can control the signal waveform generator to stop outputting the variable signal waveform to the electrically conductive coil when the temperature of the water to be treated falls below a predetermined level.

The variable signal waveform is preferably modulated between a first frequency and a second frequency at a predetermined repetition rate.

The electrically conductive coil is preferably etched on a printed circuit board using known techniques. Although the term "electrically conductive coil" has been used throughout this specification, it will be readily appreciated that the term is also intended to cover single loop and dipole antennas.

The electronic de-scaler can include means for indicating when the signal waveform generator is outputting the variable signal waveform to the electrically conductive coil. The means is preferably a light emitting diode (LED). At least a part of the waterproof housing can be made transparent so that the indicating means is visible from outside.

Drawings

Figure 1 is a sectional view showing an electronic de-scaler in accordance with the present invention; and

Figure 2 is a plan view of the printed circuit board shown in Figure 1.

Figures 1 and 2 show an electronic de-scaler according to the present invention. The electronic de-scaler includes an electrically conductive coil 2 which is etched onto a printed circuit board 4 using standard techniques. Contacts 6 are etched onto the centre of the printed circuit board 4 to which other electrical components can be attached. The electrical components include a signal waveform generator 8, a battery 10, temperature sensor 12 and a light emitting diode (LED) 14.

The signal waveform generator 8 contains a microprocessor chip (not shown). The microprocessor chip's clock functions are controlled by an external quartz crystal (not shown). An output port of the microprocessor chip is connected to the electrically conductive coil 2 by means of a resistor (not shown). An input port of the microprocessor chip is connected to the temperature sensor 12. The microprocessor chip is digitally programmed to output to a variable signal waveform to the electrically conductive coil 2 under the control of the temperature sensor 12.

The printed circuit board 4 is sealed within a moulded watertight housing 16 as shown in Figure 1. The housing 16 can be formed from any suitable plastics or resin material. Alternatively, the printed circuit board 4 (and any attached components) can be completely coated in a waterproof layer.

The LED 14 is made to flash or light when error the signal waveform generator 8 outputs the variable signal waveform to the electrically conductive coil 2 and a transparent window portion 18 allows the LED to be visible. An O-ring 20 ensures that the seal between the window portion 18 and the rest of the housing 16 is watertight. The printed circuit board 4, electrically conductive coil 2 and the attached components together form a self-contained electronic de-scaler unit that can be placed directly into a kettle. If the LED 14 fails to flash this indicates that the battery 10 has run out of energy and the electronic de-scaler unit can simply be thrown away.

The temperature sensor 12 constantly monitors the temperature of the water in the kettle. If the temperature of the water increases by at least 3°C within a 15 second time interval then the temperature sensor 12 automatically directs the signal waveform generator 8 to start outputting the variable signal waveform to the electrically conductive coil 2. The signal waveform generator 8 will continue to output the variable signal waveform for a fixed period of 2/4 minutes determinal with reference to the external quartz crystal. If the temperature of the water surrounding the electronic de-scaler is still increasing after the 2V minute period has ended, and the signal waveform generator 8 has stopped outputting the variable signal waveform to the electrically conductive coil 2, then the temperature sensor 12 will once again automatically direct the signal waveform generator 8 to start to output the variable signal waveform for a further 2V_ minutes. The process is repeated until the water has boiled or the temperature of the water no longer increases by more than 3°C within a time period of 15 seconds.

Claims

1. An electronic de-scaler for treating a volume of water comprising: an electrically conductive coil (2); a signal waveform generator (8) connected to the electrically conductive coil (2) for outputting to the electrically conductive coil a variable signal waveform; a power source (10); and a sensor (12) for automatically controlling when the signal waveform generator (8) outputs the variable signal waveform to the electrically conductive coil

(2); wherein the electrically conductive coil (2), the power source (10), the signal waveform generator (8) and the sensor (12) are enclosed within a waterproof housing (16) such that the electronic de-scaler is freely submergible in the volume of water.

2. An electronic de-scaler according to claim 1, wherein the sensor is a temperature sensor (12) and the signal waveform generator (8) starts to output the variable signal waveform when the temperature of the water to be treated rises above a predetermined level.

3. An electronic de-scaler according to claim 2, wherein the predetermined level is equal to or less than 68°C.

4. An electronic de-scaler according to claim 1, wherein the sensor is a temperature sensor (12) and the signal waveform generator (8) starts to output the variable signal waveform in response to a predetermined change in the temperature of the water to be treated.

5. An electronic de-scaler according to claim 1, wherein the sensor is a movement sensor and the signal waveform generator (8) starts to output the variable signal waveform when the movement of the electronic de-scaler in the volume of water rises above a predetermined level.

6. An electronic de-scaler according to claim 1, wherein the sensor is an acoustic sensor and the signal waveform generator (8) starts to output the variable signal waveform when the sound detected by the sensor rises above a predetermined level.

7. An electronic de-scaler according to claim 1, wherein the sensor is a pressure sensor and the signal waveform generator (8) starts to output the variable signal waveform when the pressure detected by the sensor rises above a predetermined level.

8. An electronic de-scaler according to claim 1, wherein the sensor is a proximity sensor and the signal waveform generator (8) starts to output the variable signal waveform when the electronic de-scaler is less than a predetermined distance from a surface or trigger device.

9. An electronic de-scaler according to any preceding claim, wherein the signal waveform generator (8) outputs the variable signal waveform for a predetermined amount of time.

10. An electronic de-scaler according to any preceding claim, wherein the variable signal waveform is modulated between a first frequency and a second frequency at a predetermined repetition rate.

11. An electronic de-scaler according to any preceding claim, wherein the electrically conductive coil (2) is etched on a printed circuit board (4).

12. An electronic de-scaler according to any preceding claim, further comprising a light emitting diode for indicating when the signal waveform generator (8) is outputting the signal waveform to the electrically conductive coil (2).