WO2002039107A1

WO2002039107A1 - Water monitoring device

Info

Publication number: WO2002039107A1
Application number: PCT/CA2001/001557
Authority: WO
Inventors: Iain Weir-Jones
Original assignee: Weir Jones Iain
Priority date: 2000-11-07
Filing date: 2001-11-06
Publication date: 2002-05-16
Also published as: CA2325409A1; AU2002213727A1

Abstract

A water monitoring device has water sensors (31, 33, 35, 45, 133, 139, 144, 145) mounted in a sensor body (12, 112) for sensing the properties of water, and a display (28, 128) for indicating outputs from the water sensors (31, 33, 35, 45, 133, 139, 144, 145). The sensors (31, 33, 35, 45, 133, 139, 144, 145) and the display (28, 128) are interconnected by electrical circuitry which is accommodated in a water-tight space (22, 122) in the sensor body (12, 112), and an electrical battery is provided for energizing the sensors (31, 33, 35, 45, 133, 139, 144, 145) and the display (28, 128)ba. The battery is provided in a housing (18, 118) which is removably fitted into the sensor body (12, 112), and a consumable reference cell is provided in the housing (18, 118). Alternatively the batteries may be placed in a separate housing (18, 118) and they may be replaced independently of the reference cell. In addition pH, ORP and conductivity sensors may be provided in the housing (18, 118) or they may be permanently mounted in the sensor body (12, 112).

Description

Water Monitoring Device

Technical Field

The present invention relates to a water monitoring device and is useful in particular, but not exclusively, for monitoring the chemical and/or other properties of water being supplied to a swimming pool or a hot tub.

Background Art

In order to test the water supplied to swimming pools and hot tubs, to ensure that the water has the correct chemical properties required to ensure the safety of users of the swimming pools and the hot tubs and the correct functioning of ancillary systems, it has previously been necessary to employ chemical test kits and colorimetric evaluations. Based on the results of measurements thereby obtained, various chemicals are added to the water in order to improve the chemistry of the water. These procedures are time- consuming and inconvenient.

In United States Patent No.5,681,110, issued October 28, 1997 to Alessandro Burzacchi, there is disclosed a water monitoring device, for use in a swimming pool, in which a water temperature transducer is mounted in a buoyant housing and provided with a solar panel and other components for driving display which can be read through the housing.

However, this prior device includes no means for monitoring other properties of the water.

Disclosure of the Invention

It is accordingly an object of the present invention to provide a novel water monitoring device which simplifies and facilitates the testing of the quality of water circulating, for example, in a swiinming pool or a hot tub. According to the present invention, there is provided a water monitoring device comprising a sensor body, water sensors mounted in the sensor body for sensing the properties of water, and a display for indicating outputs from the water sensors.

In a preferred embodiment of the invention, the sensors and the display are interconnected by electrical circuitry which is accommodated in a water-tight space in the sensor body, and an electrical battery is provided for energizing the sensors and the display.

The sensors are preferably provided in a housing which is removably fitted into the sensor body, and the battery may also be provided in the housing or may be provided in a separate compartment so as to be readily replaceable.

In one embodiment of the invention, the display comprises diodes controlled by a microprocessor in the the electrical circuitry and a cover secured to the sensor body and extending over the water-tight space, the cover being at least partly translucent to allow illumination of the diodes to be observed from the exterior of the water monitoring device.

Alternatively, the display may comprise a liquid crystal display (LCD), which is controlled by a microprocessor in the electrical circuitry and a cover secured to the sensor body and extending over the water-tight space, the cover being at least partly transparent to allow the digital display to be observed from the exterior of the water monitoring device. The electrical circuitry and the display may then be accommodated in a water-tight space, the housing having a housing portion extending into the watertight space and provided with an electrical connection between the battery and the electrical circuitry, and the housing being sealed in a water-tight manner to the sensor body.

In use, the present water monitoring device is installed in a pool or hot tub water pipe using a standard plumbing fitting, in such a way that the sensors are exposed to the water in the plumbing. The present water monitoring device is preferably provided with sensors for sensing the pH value, the ORP (Oxygen Reduction Potential), the conductivity and the temperature of the water, and may also indicate whether or not a pool filter needs to be replaced or cleaned.

By measurement of the conductivity and from other measurements, the total alkalinity of the water may be derived. This is of interest to pool users and maintainers because mineral salts have a tendency to precipitate in boilers and filters associated with swimming pools. The alkalinity of the pool water is also related to the rate of leaching or dissolution of the cement or plaster in the pool.

Brief Description of the Drawings

The invention will be more readily understood from the following description of an embodiment thereof given, by way of example, with reference to the accompanying the drawings, in which: -

Figure 1 show s a view tlirough a water monitoring device embodying the present invention taken in vertical cross-section along the line 1 - 1 of Figure 4;

Figure 2 shows a view taken in cross-section along the line 2-2 of Figure 1;

Figure 3 shows a top plan view of the water monitoring device of Figure 1;

Figure 4 shows an underneath plan view of the water monitoring device of Figure 1 ;

Figure 5 shows a circuit diagram of a control circuit of the water monitoring device of Figures 1 to 4;

Figure 6 shows a view through a modified water monitoring device embodying the present invention, taken in vertical cross-section along the line 6 - 6 of Figure 9; Figure 7 shows a view taken in cross-section along the line numeral 7 - 7 of Figure 6;

Figure 8 shows a top plan view of the water monitoring device of Figure 6;

Figure 9 shows an underneath plan view of the water monitoring device of Figure 6 with a shield omitted;

Figure 10 shows the water monitoring device of Figure 6 installed at in a pipe fitting, with the pipe fitting shown in cross-section; and

Figure 11 shows a circuit diagram of the water monitoring device of Figure 6.

Description of the Best Mode

As shown in the accompanying the drawings, a water monitoring device indicated generally by reference numeral 10 has a sensor body 12 provided with a cover, indicated generally by reference numeral 13, which is formed by an annular molding 14 and a disk 16 fitted into the annular molding 14. The cover 13 is secured to the sensor body 12 by screws 15. The sensor body 12, the molding 14 and the disk 16 made of plastic material, and the disk 16 is made of transparent plastic material.

A housing indicated generally by reference numeral 18, which is also made of plastic material, is fitted into the sensor body 12 and has an upper portion or cap indicated generally by reference numeral 20 which projects into a water-tight space 22 formed in the sensor body 12 and closed by the cover 13. The housing 18 also has a lower portion indicated generally by reference numeral 21, enclosing a battery compartment 23, and the upper portion 20 is sealed to the lower portion 21 so as to close the top of the battery compartment 23. A sealing ring 24 is provided between the housing 18 and the sensor body 12 to provide a water-tight seal between these components. The water-tight space 22 accommodates a circuit board 26 provided with a plurality of diodes 28. The battery compartment 23 accommodates a battery 30 which, at its upper end, is connected by an electrical connection 32 extending through the top portion 20 of the housing 18 into electrical contact with the circuitry on the circuit board 26.

In addition to the battery 30, the housing 18 is provided with a reference cell comprising a silver/silver chloride electrode 35 immersed in a silver chloride solution 37 serving as an electrolyte, in an electrolyte compartment 39 in the housing. A porous plug 41 at the bottom of the housing allows for the diffusion of the charged ions and the completion of the electrical circuit to a pH sensor 33 in the form of a glass bulb sensor of high impedance, which senses the pH value of water diffusing into the pH sensor 33.

Alternatively, the pH sensor 33 may be removed from the housing 18 and attached to the lower part of the sensor body 12. In that case, when the reference sensor electrolyte is exhausted or the battery is dead, only the housing 18 needs be replaced. The sensor body 12 is also fitted with a temperature sensor 43 located in a blind hole in the sensor body 12 so that the temperature sensor 43 measures water temperature by conduction, and an

ORP sensor 31.

The sensor body 12 is formed with a frusto-conical lower portion 34 which is threaded for threaded engagement with a standard pipe fitting (not shown). The sensor body 12 is also formed with four or more through-openings 36 (Figure 2) for receiving other water quality sensors. These other sensors may comprise conductivity sensors, pressure sensors, specific ion probes.

A cup-shaped metal shield 45 extends around and encloses the portion of the housing 18 which projects downwardly from the sensor body 12, the shield 45 being engaged at its top by a press fit with an annular downwardly extending projection 47 at the underside of the sensor body 12. The shield 45 provides an electrical shielding for the sensors, and in particular for the pH sensor 33, which is susceptible to electrical noise, and also provides mechanical protection for the sensors. Two holes 49 and 50 in the shield 45 allow water from the exterior of the shield to circulate past the sensors. Referring now to Figure 3, which shows a plan view of the disk 16 forming part of the cover 13, it will be seen that a disk 16 is provided with lettering indicating three water qualities, namely pH, ORP and total alkalinity. Each of these qualities is associated with three window openings 40 through which illumination of respective diodes 28 can be observed from the exterior of the water monitoring device 10, the remainder of the disk surface being covered with paint.

The top surface of the disk 16 is also provided, as shown, with three different letterings indicating, respectively, "Too Low", "OK" and "Too High".

The electrical circuitry on the printed circuit board 26 is illustrated in the circuit diagram of Figure 5 and has input terminals Tl - T6, which are connected to the pH electrode 33, the ORP electrode 31, the reference electrode 35, a conductivity sensor (not shown) and a temperature sensor 43, respectively. The terminals Tl and T2 are connected through a pair of high impedance differential amplifiers Al and A2, and switches SI- S4 to a microprocessor 42 which controls the diodes 28. The microprocessor 42 implements calibration procedures whenever the batteries or the reference electrode assembly are replaced. In this way, the precision of the pH sensor is optimized.

The present monitoring device is not restricted to the sensors mentioned above but in addition, or alternatively, may be provided with sensors for pressure, concentrations of specific ions, etc. Also, by measuring the back pressure against a filter (not shown), and by comparing this measurement with a corresponding measurement value obtained when the filter is new, it is possible for the monitoring device 10 to provide an indication of whether or not the filter needs to be replaced or cleaned.

The housing 18, containing the battery 13 and the reference cell, may be designed to have a battery capacity and a projected reference cell life such that the housing 18 and its contents form a replaceable unit which will last a complete pool season, i.e. about 6-7 months, before needing replacement. At the beginning of each season, the owner or maintainer will install a replacement unit comprising a new housing 18 with its associated battery and sensors. The monitoring device 10 will then automatically carry out a calibration sequence so that the water monitoring device 10 would become fully operable in an automatic manner, i.e. without further human input.

In Figures 6 to 11 of the accompanying drawings, there is illustrated a modified water monitoring device embodying the present invention, which is indicated generally by reference numeral 110 and which has a sensor body 112 provided with a cover, indicated generally by reference numeral 113. The cover 113 is secured to the sensor body 112 by screw threads 115 and 116 on the cover 113 and the sensor body 112. The cover 113 is sealed to the sensor body 112 by means of an O-ring 117. The sensor body 112 and the cover 113 are made of transparent plastic material, and the cover 113 is at least partially transparent.

A housing 118 is secured in threaded engagement with the sensor body 112 and has an upper portion 120 projects into a cylindrical recess 121 formed in the sensor body 112. The upper portion 120 of the housing 118 is sealed to the sensor body 112 by means of a sealing ring 124, which provides a watertight seal for the cylindrical recess 121.

The top of the sensor body 112 is recessed to form a space 122 which is closed in a watertight manner by an O-ring 117. The watertight space 122 accommodates a circuit board 126 provided with an LCD 128.

A battery compartment 123 is provided in a laterally protecting portion 125 of the sensor body 112 and closed by a threaded cap 124. The battery compartment 123 contains batteries 130 which are connected by connection leads 132 to the circuit board 126.

The housing 118 is sealed in a watertight manner to the sensor body 112 by an O-ring 121 and encloses a compartment 139 containing a reference cell comprising a silver/silver chloride electrode 135 immersed in a silver chloride solution 137 serving as an electrolyte. A porous plug 141 in the wall of the housing 118 allows for diffusion of charged ions and the completion of electrical circuits between a pH sensor 133 and an

ORP sensor 139. The pH sensor 133 comprises a glass bulb of high impedance, which senses the pH value of water defusing into the pH sensor 133 and the ORP sensor 139 comprising is a graphite or precious metal electrode adjacent the pH sensor 133.

The sensor body 112 also contains a conductivity sensor 144, and a temperature sensor 145, and the sensors projecting from the sensor body 112 are enclosed in a cup-shaped shield 146 which is fitted onto a cylindrical bottom portion 147 of the sensor body 112 and formed with holes 149 and 151 to allow water from the exterior of the shield 146 to circulate past the sensors. The shield 146 provides electrical and mechanical shielding for the sensors and has been omitted from Figure 9 to facilitate the illustration of the monitor 110.

In the watertight space 122, within the sensor body 112, the LCD 128 is mounted in a disk 148, which is supported on screws 150 in threaded engagement with the sensor body 112. The LCD 128 is visible from the exterior of the water monitoring device through the transparent cover 113. The transparent disk 147 also supports a liquid crystal display

128, which serves to display three water qualities, namely ORP, pH and petrol alkalinity, as well as water temperature.

Figure 10 shows the sensor body 112 in threaded engagement with a pipe fitting and, more particularly, with a T- fitting 152 by means of a screw thread 154 on frusto-conical portion 156 of the sensor body 112 and a corresponding screw thread 158 on the fitting 152.

Figure 11 shows an electrical circuit diagram of the electrical circuit of the monitor of Figures 6 to 10 and, since most of the components of this circuit are identical to those of Figure 5, they are indicated by the same references and are not again described herein. It will, however, be seen that the diodes 28 of Figure 5 have been replaced in Figure 11 by the LCD 128.

By appropriate current design, the power consumptions of the above-described water monitoring devices can be reduced sufficiently to ensure that the battery life is extended beyond the life of the reference cell. The batteries and the reference cell can then be replaced independently of one another while still maintaining the above- described automatic calibration sequence.

As will be apparent to those skilled in the art, various modifications and improvements may be made in the above-described water monitoring devices.

For example, it is envisaged that the water monitoring device may be equipped with a low power radio transmitter for transmitting numerical values of the various parameters of the water being monitored to a display unit, which may, for example, be mounted in the user' s home. This would eliminate any need for the pool owner to visit a pool shed or pump room to view the water chemistry values.

Instead of employing a radio link for this purpose, it would also be possible to provide an electrical connection between the water monitoring device and the display in the user's home.

It would also be possible to modify the present device so as to permit the user or maintainer of the pool not only to access the water chemistry values remotely but also to determine in advance the amount of chemicals required to be added to the water. Furthermore, the present monitoring device may be modified to act as a controller for metering devices dispensing appropriate quantities of chemicals, in liquid or dry form, into the pool water in order to maintain the water quality and balance automatically with minimal operator intervention.

Claims

Patent Claims

1. A water monitoring device, characterized by a sensor body (12, 112), a plurality of water quality sensors (31, 33, 35, 45, 133, 139, 144, 145) mounted in the sensor body (12, 112), a water quality display (28, 128) in the sensor body (12, 112), the sensor body (12, 112) having a window (13, 113) through which the water quality display (28, 128) is visible from the exterior of the sensor body (12, 112), an electrical circuit within the sensor body (12, 112) connecting the water quality sensors (31, 33, 35, 45, 133, 139, 144, 145) to the water quality display

(28, 128), a battery compartment (23, 123) and at least one battery in the battery compartment (23, 123) for energizing the electrical circuit.

2. A water monitoring device has claimed in claim 1, characterized in that the sensors include a consumable reference cell provided in a housing (18, 118) which-is releasibly secured to the sensor body (12, 112) to facilitate replacement of the reference cell, a watertight seal (24, 124) being provided between the housing (18, 118) and the sensor body (12, 112).

3. A water monitoring device has claimed in claim 2, characterized in that the housing (18, 118) includes a compartment (39, 139) holding an electrolyte (37, 137) and an electrode (35, 135) in the electrolyte (37, 137), with a porous plug (41, 141) between the compartment and the exterior of the water monitoring device.

4. A water monitoring device has claimed in the claim 1, 2 or 3, characterized in that the sensor body (12, 112) includes a space (22, 122) containing the water quality display (28, 128) and the window comprises a removable cover (113) enclosing the space (22, 122) with a watertight seal (12, 117) between the removable cover and the sensor body (12, 112).

5. A water monitoring device has claimed in any of claims 1 to 4, characterized in that the electrical circuit includes a microprocessor (41) controlling the water quality display (28, 128) in response to outputs of the water quality sensors (31, 33, 35, 45, 133, 139, 144, 145) and recalibrating the water quality display (28, 128) on replacement of the battery (30 or) batteries (130) or one of the water quality sensors.

6. A water quality monitor as claimed in any preceding claim, characterized in that the water quality sensors comprises apH sensor, and oxygen reduction potential sensor, a water conductivity sensor and a water temperature sensor.

7. A water monitoring device as claimed in any preceding claim, characterized in that the sensor body (112) is installed in a pipe fitting (152).