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Title:
A CHILLED WATER DISPENSER AND A METHOD OF OPERATING SAME
Document Type and Number:
WIPO Patent Application WO/2018/094446
Kind Code:
A1
Abstract:
A method of automatically sanitising and/or disinfecting water in a chilled water dispenser (100), the method including the steps of: at predetermined time intervals, de-energising a refrigeration means (120) in the chilled water dispenser (100); energising a heating means (130) associated with the chilled water dispenser (100) to heat water within a water storage tank (110) to a first predetermined temperature sufficient to kill bacteria and/or pathogens in the water, thereby sanitising and/or disinfecting the water; maintaining the temperature of the water at or above the first predetermined temperature for a predetermined period of time; at the end of the predetermined period of time above, de-energising the heating means (130); and re- energising the refrigeration means (120) to chill the water to a second predetermined temperature sufficient to be deemed suitable for human consumption as chilled drinking water.

Inventors:
MOULT KEVIN (AU)
SCOTT HAYDEN (AU)
NOBLE GARY (AU)
Application Number:
AU2017/000250
Publication Date:
May 31, 2018
Filing Date:
November 24, 2017
Export Citation:
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Assignee:
ZIP IND AUST PTY LTD (AU)
International Classes:
B67D1/08; C02F1/02; F25D23/12
Domestic Patent References:
WO2016197242A12016-12-15
Foreign References:
US6143258A2000-11-07
US20100074816A12010-03-25
US6207046B12001-03-27
US20060049089A12006-03-09
EP1927573A12008-06-04
Attorney, Agent or Firm:
SPRUSON & FERGUSON (Sydney, New South Wales 2001, AU)
Download PDF:
Claims:
CLAIMS:

1. A method of sanitising and/or disinfecting water in a chilled water dispenser, the method including the steps of:

at predetermined time intervals, de-energising a refrigeration means in the chilled water dispenser;

energising a heating means associated with the chilled water dispenser to heat water within a water storage tank to a first predetermined temperature sufficient to kill bacteria and/or pathogens in the water, thereby sanitising and/or disinfecting the water;

maintaining the temperature of the water at or above the first predetermined temperature for a predetermined period of time;

at the end of the predetermined period of time above, de-energising the heating means; and

re-energising the refrigeration means to chill the water to a second predetermined temperature sufficient to be deemed suitable for human consumption as chilled drinking water.

2. The method as claimed in claim 1 , further including the steps of:

disabling a dispensing operation of the chilled water dispenser before the water within the water storage tank reaches the first predetermined temperature, and preferably before the step of de-energising the refrigeration means; and

re-enabling the dispensing operation of the chilled water dispenser after the

predetermined period of time, preferably after the step of re-energising the refrigeration means.

3. A method of automatically sanitising and/or disinfecting water in a chilled water dispenser, the method including the steps of:

at predetermined time intervals, disabling a dispensing operation of the chilled water dispenser and de-energising a refrigeration means in the chilled water dispenser;

energising a heating means associated with the chilled water dispenser to heat water within a water storage tank to a first predetermined temperature sufficient to kill bacteria and/or pathogens in the water, thereby sanitising and/or disinfecting the water;

maintaining the temperature of the water at or above the first predetermined temperature for a predetermined period of time;

at the end of the predetermined period of time , de-energising the heating means; re-energising the refrigeration means to chill the water to a second predetermined temperature sufficient to be deemed suitable for human consumption as chilled drinking water; and

re-enabling the dispensing operation of the chilled water dispenser.

4. The method as claimed in any one of claims 1 to 3, wherein the first predetermined temperature is in a range of about 75°C to 85°C, preferably about 78°C.

5. The method as claimed in any one of claims 1 to 4, wherein second predetermined temperature is in a range of about 5°C to 20°C.

6. The method as claimed in any one of claims 1 to 5, wherein the predetennined time intervals include: daily; every 48 hours; every 72 hours; weekly; fortnightly; and monthly.

7. The method as claimed in any one of claims 1 to 6, wherein predetermined time period is at least about 10 minutes.

8. The method as claimed in any one of claims 1 to 7, wherein the method includes, during the predetermined period of time, the step of activating a pump to purge water pathways associated with the chilled water dispenser with water at the first predetermined temperature, thereby killing bacteria and/or pathogens in any residual water within the water pathways.

9. The method as claimed in any one of claims 1 to 8, wherein the method further includes the step of pulsating the pump at predetennined frequencies to direct the water from the water storage tank through the water pathways.

10. A chilled water dispenser comprising:

a water storage tank;

refrigeration means adapted to chill water in the tank upon activation;

heating means adapted to heat the water in the tank upon activation; and

a controller operably associated with the refrigeration means and the heating means, the controller being configured to:

activate the refrigeration means to chill the water in the tank; at predetermined time intervals, de-activate the refrigeration means and activate the heating means to heat the water in the tank to a first predetennined temperature sufficient to kill bacteria and/or pathogens in the water to sanitise and/or disinfect the water;

maintain the temperature of the water at or above the first predetermined temperature for a predetermined period of time;

de-activate the heating means after the predetermined period of time; and re-activate the refrigeration means to chill the temperature of the water to a second predetermined temperature sufficient to be deemed suitable for human

consumption.

1 1. The chilled water dispenser as claimed in claim 10, wherein the controller is configured to: enable a dispensing operation of the chilled water dispenser; and

disable the dispensing operation of the chilled water dispenser before the water within the water storage tank reaches the first predetermined temperature, and preferably before the refrigeration means is deactivated.

12. The chilled water dispenser as claimed in claim 10 or claim 11 , wherein the heating means is an electrically powered heating pad positioned against an external surface at a base of the water storage tank.

13. The chilled water dispenser as claimed in claim 12, wherein the heating pad is adhered to the external surface of the water storage tank.

14. The chilled water dispenser as claimed in any one of claims 10 to 13, wherein the heating means is an electrically powered heating element positioned within the water storage tank.

Description:
A CHILLED WATER DISPENSER AND A METHOD OF OPERATING SAME

FIELD OF THE INVENTION

[0001 ] The present invention relates to a chilled water dispenser and a method of operat same. The invention has primarily been developed for use with chilled drinking water dispensers, and will be described hereinafter with reference to this application.

BACKGROUND OF THE INVENTION

[0002] A known chilled water dispenser typically comprises a water chilling tank and a refrigeration evaporator. The refrigeration evaporator is either submerged in water within the tank or attached to an external surface of the tank. The dispenser typically utilises a thermostat or thermistor to regulate and reduce the water temperature to a desirable level for human consumption. Chilled water is dispensed from the tank through conventional means such as a valve (i.e. a pressure push through system) or a pump (i.e. a pumped vented system) connected to a water outlet spout.

[0003] A disadvantage of known chilled water dispensers is that the water contained within the chilling tank is susceptible to common waterborne bacteria and opportunist pathogens (e.g. Legionella and pseudomonas aeruginosa) infiltration and contamination. Water that is contaminated with Legionella bacteria or pathogens can spread into urban water systems such as residential or commercial plumbing systems and water tanks, and subsequently fed into the chilling tanks of chilled water dispensers. The water may alternatively be contaminated through back-contamination at the water outlet spouts. Filtration systems within conventional chilled water dispensers may not adequately filter out all bacteria or pathogens. Legionella bacteria, for example, typically thrive in water at temperatures ranging between 20 degrees Celsius to 50 degrees Celsius.

[0004] Water that is contaminated with bacteria or pathogens is particularly harmful to persons with weak immune systems or patients with respiratory illnesses, possibly occasioning death. For example, Legionella exposure can occur when a person inhales small droplets of water (e.g. from a showerhead or whilst drinking water dispensed from a chilled water dispenser) containing Legionella bacteria. The water should therefore ideally be maintained at temperatures ranging between 5 degrees Celsius to 20 degrees Celsius, given that Legionella bacteria typically remain dormant in these temperatures, limiting growth of the bacteria. In general, most bacteria and pathogens including Legionella will begin to die in water temperatures of around 55 degrees Celsius, whilst the majority of common waterborne bacteria and opportunist pathogens will die in water temperatures of around 75 degrees Celsius, depending on the length of exposure.

OBJECT OF THE INVENTION

[0005] It is an object of the present invention to substantially overcome one or more of the above disadvantages.

SUMMARY OF THE INVENTION

[0006] Accordingly, in a first aspect, the present invention provides a method of automatically sanitising and/or disinfecting water in a chilled water dispenser, the method including the steps: at predetermined time intervals, de-energising a refrigeration means in the chilled water dispenser;

energising a heating means associated with the chilled water dispenser to heat water within a water storage tank to a first predetermined temperature sufficient to kill bacteria and/or pathogens in the water, thereby sanitising and/or disinfecting the water;

maintaining the temperature of the water at or above the first predetermined temperature for a predetermined period of time;

after the predetermined period of time, de-energising the heating means ; and

re-energising the refrigeration means to chill the water to a second predetermined temperature sufficient to be deemed suitable for human consumption as chilled drinking water.

[0007] Preferably, the method further includes the step of:

disabling a dispensing operation of the chilled water dispenser before the water within the water storage tank reaches the first predetermined temperature, and preferably before the step of de-energising the refrigeration means; and

re-enabling the dispensing operation of the chilled water dispenser after the

predetermined period of time, and preferably after the step of re-energising the refrigeration means. [0008] In a second aspect, the present invention provides a method of automatically sanitising and/or disinfecting water in a chilled water dispenser, the method including the steps of:

at predetermined time intervals, disabling a dispensing operation of the chilled water dispenser and de-energising a refrigeration means in the chilled water dispenser;

energising a heating means associated with the chilled water dispenser to heat water within a water storage tank to a first predetermined temperature sufficient to kill bacteria and/or pathogens in the water, thereby sanitising and/or disinfecting the water;

maintaining the temperature of the water at the first predetermined temperature for a predetermined period of time;

at the end of the predetermined period of time above, de-energising the heating means; re-energising the refrigeration means to chill the water to a second predetermined temperature sufficient to be deemed suitable for human consumption as chilled drinking water; and

re-enabling the dispensing operation of the chilled water dispenser.

[0009] The first predetermined temperature is preferably at least about 55°C, more preferably in the range of about 75°C to about 85°C, and particularly preferably about 78°C.

[0010] The second predetermined temperature is preferably in the range of about 5°C to about 20°C.

[001 1 ] The predetermined time intervals preferably include: daily; every 48 hours; every 72 hours; weekly; fortnightly; and monthly.

[0012] The predetermined time period is preferably at least about 10 minutes.

[0013] The method preferably includes, during the predetermined period of time, the step of activating a pump to purge water pathways associated with the chilled water dispenser with water at the first predetermined temperature, thereby killing bacteria and/or pathogens in any residual water within the water pathways.

[0014] The method preferably further includes the step of pulsating the pump at predetermined frequencies to direct the water from the water storage tank through the water pathways. [0015] In a third aspect, the present invention provides a chilled water dispenser comprising: a water storage tank;

refrigeration means adapted to chill water in the tank upon activation;

heating means adapted to heat the water in the tank upon activation; and

a controller operably associated with the refrigeration means and the heating means, the controller being configured to:

activate the refrigeration means to chill the water in the tank;

at predetermined time intervals, de-activate the refrigeration means and activate the heating means to heat the water in the tank to a first predetermined temperature sufficient to kill bacteria and/or pathogens in the water to sanitise and/or disinfect the water;

maintain the temperature of the water at or above the first predetermined temperature for a predetermined period of time;

de-activate the heating means after the predetermined peri od of time; and re-activate the refrigeration means to chill the temperature of the water to a second predetermined temperature sufficient to be deemed suitable for human consumption as chilled drinking water.

[0016] Preferably, the controller is furthermore configured to:

enable a dispensing operation of the chilled water dispenser; and

disable the dispensing operation of the chilled water dispenser before the water within the water storage tank reaches the first predetermined temperature, preferably before the

refrigeration means is deactivated.

[0017] The heating means is preferably an electrically powered heating pad positioned against an external surface at a base of the water storage tank.

[0018] The heating pad is preferably adhered to the external surface of the water storage tank.

[0019] The heating means may alternatively be an electrically powered heating element positioned within the water storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawing:

[0021] Fig. 1 shows a schematic side view of an embodiment of a chilled water dispenser; and [0022] Fig. 2 shows a schematic side view of another embodiment of a chilled water dispenser.

DETAILED DESCRIPTION OF EMBODIMENTS

[0023] Fig. 1 shows an embodiment of a chilled water dispenser 100. The chilled water dispenser 100 includes a water storage tank 1 10, a refrigeration means 120, a heating means 130 and a controller 140. The water storage tank 1 10 includes an inlet 1 12 for receiving water from a water supply and an outlet 1 14 adapted to dispense water from the water storage tank 1 10. The chilled water dispenser 100 further includes a pump 150 connected to the water storage tank 110 at the outlet 1 14 and a dispensing tube 160 having a tube outlet 162 for dispensing water from the outlet 1 14. The chilled water dispenser 100 further includes a water level sensor 170 disposed at an upper end of the water storage tank 1 10 and a temperature sensor 180 in the form of a thermostat or thermistor disposed within the water storage tank 1 10.

[0024] The refrigeration means 120 is disposed within the water storage tank 1 10 and is in the form of a refrigeration evaporator coil which is immersed in water in the water storage tank 1 10 during use. The refrigeration means 120 is powered by a refrigeration power source (not shown) and is adapted to chill water in the water storage tank 1 10 upon activation. The heating means 130 is in the form of an electrically powered heating pad positioned against and adhered to an external surface at a base of the water storage tank 1 10. The heating pad includes an element wire encased in a silicone overmoulded construction. The silicone overmoulded construction includes an adhesive disposed on one side to facilitate the adhesion of the h eating pad to the external surface of the water storage tank 1 10. The heating means 130 is powered by a heating power source (not shown) and is adapted to heat the water in the water storage tank 110 upon activation. It is envisaged that the heating power source is has a relatively low power rating of approximately 200 Watts. [0025] The controller 140 is located externally of the water storage tank 1 10 and is operably associated with the refrigeration means 120 and the heating means 130. The controller 140 is programmed to activate and de-activate the refrigeration means 120 and the heating means 130 during use. The controller 140 is also programmed to enable and disable a dispensing operation of the chilled water dispenser 100 by controlling the opening and closing of the inlet 1 12 and the outlet 1 14. The controller 140 is also programmed to control the operation of the pump 150 operably associated with the chilled water dispenser 100.

[0026] A method of automatically sanitising and/or disinfecting water in the chilled water dispenser 100 will now be described. The controller 140 undertakes the following method steps:

[0027] At predetermined time intervals, a dispensing operation of the chilled water dispenser 100 is disabled and the refrigeration means 120 is de-energised. The heating means 130 is then energised to heat water within the water storage tank 1 10 to a first predetermined temperature of between about 75°C and 85°C (preferably about 78°C) sufficient to kill bacteria and/or pathogens in the water, thereby sanitising and/or disinfecting the water. The temperature of the water is then maintained at or above the first predetermined temperature for a predetermined period of time of at least about 10 minutes. Although even higher temperatures (e.g. 90°C and above) are conceivable for sanitizing or disinfecting the water tank, such higher temperatures can lead to additional safety concerns or requirements for a chilled water dispenser, which can be disadvantageous.

[0028] At the end of the predetermined period of time of at least about 10 minutes above, the heating means 130 is de-energised. The refrigeration means 120 is then re-energised to chill the water to a second predetermined temperature of between about 5°C and about 20°C sufficient to be deemed suitable for human consumption as cool or chilled drinking water. The dispensing operation of the chilled water dispenser 100 is then re-enabled.

[0029] The above sanitisation/disinfection process typically runs for a total duration of about 90 to 120 minutes. The controller 140 is programmed to disable the dispensing operation of the chilled water dispenser 100 at any of the following predetermined time intervals: daily, every 48 hours, every 72 hours, weekly, fortnightly or monthly. [0030] During the predetermined time period of 10 minutes above, the controller 140 activates the pump 150 to purge water pathways (including, for example, the tank outlet 1 14, the dispensing tube 160 and the tube outlet 162) associated with the chilled water dispenser 100. In this way, the water pathways or the pipework between the water storage tank 1 10 and the tube outlet 162 can be purged with water at the first predetermined temperature , thus raising the surface temperature of the water pathways or pipework to above about 70°C. This has the effect of killing bacteria and/or pathogens in any residual water within the water pathways, thus sanitising the water pathways. The hot water pumped via the pump 150 into the pipework between the water storage tank 1 10 and the tube outlet 162 then drains back into the water storage tank 110. The controller 140 may be programmed to pulsate the pump 150 at a predetermined frequency about 20 times during the predetermined time period to re-fill and drain the pipework or water pathways repeatedly, thereby to increase the exposure time of the pipework or water pathways to the water at the first predetermined temperature and ensure that those water pathways are thoroughly sanitised. This pulsing process may typically run for a total duration of about 30 to 50 seconds. The controller 140 may be programmed to select and control the amount of water delivered to the water pathways by the pump 150 in order to just fill the entire pipework from the tank outlet to the tube outlet 162 with each pulsation of the pump 150 during the cycle of sanitising or heating water pathways.

[0031] The chilled water dispenser 100 is typically supplied with the predetermined

temperatures and time periods as set out above. A user will then be able to program the controller 140 to select how frequently they would like sanitisation/disinfection process to occur, as well as the desired time of the day that the process is to begin. This will typically be during an expected period of non-use, for example at midnight, when there is a lower demand for chilled water.

[0032] The chilled water dispenser and the method of operation described above have a number of advantages. The method of operation is automated to allow for the water in the chilled water dispenser to be periodically sanitised and/or disinfected, thus substantially decreasing the prevalence of bacteria and/or pathogens in the water. As such, the risk of users being exposed to and infected by bacteria and/or pathogens in the water is also reduced. The method of operation also allows for the purging and sanitisation/disinfection of any residual water in the water pathways (e.g. water outlets, dispensing tubes and hoses) associated with the water dispenser, which has the effect of both reducing the prevalence of bacteria and/or pathogens in the residual water within the water pathways and also preventing back-contamination at the water outlets.

[0033] Fig. 2 shows another embodiment of a chilled water dispenser 100', which operates in a similar manner to the chilled water dispenser 100 described above, with like reference numerals being used to indicate like features. However, in this embodiment, the heating means 130 is in the fonn of an electrically powered heating element positioned within the water storage tank 1 10. The heating element has an elongate structure (such as a tube or rod) and extends from an upper portion of the water storage tank 1 10 towards a lower portion of the storage tank such that, during use, the heating element is immersed in water in the water storage tank 1 10. Similar to the heating pad of the chilled water dispenser 100 described above, it i s envisaged that the heating element has a relatively low power rating of about 200W sufficient to heat the water within the water storage tank 1 10.

[0034] Although the invention has been described with reference to preferred embodiments, it will be appreciated by persons skilled in the art that the invention may be embodied in many other forms. For example, in other embodiments (not shown), the heating pad and the controller are adapted to be retrofitted to an existing chilled water dispenser. It is also envisaged that the controller on the existing chilled water dispenser is programmable to operate in accordance with the above method by way of a software update. It is also envisaged that in another embodiment (not shown), the water storage tank may be in the form of a pressurised carbonation tank adapted to introduce carbon dioxide into the water, such that the chilled water dispenser may provide carbonated drinking water. The chilled water dispenser may also include a heat exchanger in the fonn of a solid block of aluminium that surrounds the tank and within which the evaporator of the refrigeration means is provided. The water to be cooled may then be passed through a tube arranged within the aluminium block. In this embodiment, the heating element may also be set within the block of aluminium so that, during the sanitising/disinfecting procedure, the block is heated to transfer the heat to the water in the tank. The aluminium block disposed adjacent or around the heating element facilitates the transfer of heat from the heating element to the water within the water storage tank.