WO2001079733A1

WO2001079733A1 - Improvements in boiling and/or chilling water units

Info

Publication number: WO2001079733A1
Application number: PCT/AU2001/000410
Authority: WO
Inventors: Raymond Dennis Massey; Philip Ross Pepper; Wieslaw Henryk Sliwa
Original assignee: Zip Heaters (Australia) Pty Limited
Priority date: 2000-04-14
Filing date: 2001-04-11
Publication date: 2001-10-25
Also published as: TW500899B; AUPQ691200A0

Abstract

A boiling and/or chilling water unit is disclosed that provides numerous operational and safety advantages. A first advantage is the avoidance of pressure spikes damaging a first control valve adjacent the main water inlet by controlling the relative timing between the closure of it and downstream second and/or third flow control valves. Another advantage flows from monitoring the length of time the unit's compressor has been continuously activated without the device being operated to supply chilled water and removing water and/or power supplies from the water unit upon detection of a predetermined period of that time. Another advantage flows from the control means removing water and/or power supplies from the water unit upon a level sensor indicating the presence of a predetermined level of water in a catch tray beneath the units' water tank(s). The use of flow restrictors between the mains water inlet and the unit's water tanks to control the flow from these water tanks is also disclosed.

Description

Improvements in Boiling and/or Chilling Water Units

Field of the Invention

The present invention relates to improvements in boiling and/or chilling water units, as used to provide boiling (or near boiling) and/or chilled water in kitchens, tea rooms, cafeterias and the like.

The invention has been developed primarily for use in a combined boiling and chilling ("boiling/chilling") water unit and will be described hereinafter with reference to this application. However, some aspects of the invention can be applied to either boiling water units or chilling water units.

Background of the Invention Known boiling/chilling water units comprise a heating water tank and a chilling water tank, both connected to mains water supply. A filter is interposed between the mains water supply and the heating and chilling water tanks to remove any substances or particulates or the like from the mains water supply, per the specification of the filter.

The preferred storage temperature of chilled water is about 3 or 4°C. Water shrinks during chilling until it reaches about 4°C, after which further chilling causes it to expand.

To meet Australian regulatory requirements, a non return valve must be placed between the mains water supply and the filter to prevent backflow.

A disadvantage of this arrangement is that if, for example, the temperature regulation of the water in the chilling water tank fails, the water therein can freeze. Freezing water can generate pressures in excess of 3000kpa which can damage: the filter; the piping between the non return valve and the chilling water tank; or the chilling water tank itself. One method of addressing this problem is to install a pressure relief valve before the non return valve which is set at, for example, 700kpa. This adds to the cost and complexity of the boiling/chilling water unit. Another method is to remove the nonreturn valve, contrary to the regulatory requirements.

The flow of water leaving the chilled water tank is normally controlled by a tap. Opening of the tap causes a pressure drop in the tank from static to dynamic pressure and results in the tank contracting. Closing of the tap causes a reverse pressure rise and tank expansion. Continual opening and closing of the tap causes the tank to repeatedly expand and contract which can lead to metal fatigue and consequently damage of the tank.

A further problem associated with controlling outlet flow from the chilled water tank with a tap is that, if a malfunction causes the tank to freeze, there is nowhere for the chilling water to expand to and the tank can be damaged. This problem can be overcome by using a free outlet on the chilling water tank. However, this requires a flow control valve to be installed between the filter and the tank to control the flow of water into the chilled water tank and out of the free outlet. In that case, closing the flow control valve creates a pressure spike (sometimes known as water hammer) which is trapped between the mains water supply non return valve referred to above and the flow control valve which can damage the piping and filter therebetween. Further, any pressure spikes created by pumping stations, or other means, in the main water supply are also trapped between these two valves. Addressing this problem by positioning the filter between the inlet valve and the tank subjects the filter to the same static to dynamic pressure changes as the tank which can result in run-on water flow through the free outlet, which is undesirable and can appear as a leak to the consumer.

It is known to reduce the tank expansion and contraction by reducing the pressure of the mains water supply before it enters the chilled water tank. However, a problem associated with pressure reduction is it can result in variations in the water flow rate outside of the preferred range.

It is an object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages and/or to provide improvements in boiling/chilling water units and the generation and protection of same. Summary of the Invention

Accordingly, in a first aspect, the present invention discloses a boiling and/or chilling water unit including: a mains water inlet; a chilling water tank in controlled fluid communication with the mains water inlet; and/or a heating water tank in controlled fluid communication with the mains water inlet; a first flow control valve between the mains water inlet and the chilling and heating water tanks; a second flow control valve between the chilling water tank and the first control valve; and/or a third flow control valve between the heating water tank and the first control valve; and a control means adapted to close the first control means a predetermined amount of time after the closure of the second or third flow control valves, wherein the predetermined period of time is sufficient to allow any pressure spike incident on the second or third flow control valves to travel back towards and through the first flow control valve before closure of same.

The first, second and third flow control valves are preferably electrically actuated solenoid valves. The boiling/chilling water unit preferably also includes a first and a second flow restrictor between the second flow control valve and the chilling water tank and the third flow control valve and the heating water tank respectively. The flow restrictors are preferably in the form of orifices. The orifices are preferably O-rings. The chilling and/or boiling water tanks preferably each include a tank outlet connected to an expansion chamber via a venturi opening, the tank outlets leading to respective chilled and heated water outlets.

The water outlets are preferably located in a common spout assembly. The spout assembly preferably also comprises chilled and heated water flow control switches and temperature indicator lights, all of which being in communication with the control means.

In a second aspect, the present invention provides a method of operating a boiling and/or chilling water unit, the water unit including: a mains water inlet; a chilling water tank in controlled fluid communication with the mains water inlet; and/or a heating water tank in controlled fluid communication with the mains water inlet; a first flow control valve between the mains water inlet and the chilling and heating water tanks; a second flow control valve between the chilling water tank and the first control valve; and/or a third flow control valve between the boiling water tank and the first control valve; and a control means, the method including the step of closing the first flow control valve a predetermined time after closure of the second or third flow control valves, the predetermined time being sufficient to allow any pressure spikes incident on the second or third flow control valves to travel back towards and through the first flow control valve before closure of the first flow control valve.

In a third aspect, the present invention provide a chilling or boiling/chilling water unit including: a chilling water tank with a chilled water tank outlet, a chilled water free outlet and a chilled water expansion chamber, wherein the tank outlet is in direct fluid communication with the free outlet and the expansion chamber is in fluid communication with the tank outlet via a venturi opening in the tank outlet. In a fourth aspect, the present invention provides a method of controlling a chilling or boiling/chilling water unit, the water unit including: a chilling water tank; a compressor connected to cooling coils associated with the chilling water tank; and a device operable to cause water flow from the chilled water tank, the method including the steps of: monitoring the length of time the compressor has been continuously activated without the device being operated; and removing water and/or power supplies from the boiling/chilling water unit upon detection of the compressor being continuously activated without the device being operated for more than a predetermined period of time.

In a fifth aspect, the present invention provides a chilling or boiling/chilling water unit including: a control means; a chilling water tank; a compressor connected to cooling coils associated with the chilling water tank and associated with the control means; and a device operable to cause water flow from the chilled water tank, wherein the control means is adapted to remove water and/or power supplies from the boiling/chilling water unit upon detection of the compressor being continuously activated for more than a predetermined period of time without the device being operated.

The predetermined period of time is preferably one hour.

The unit/method can also include the issuance of a failure or service required signal to a building maintenance system upon detection of the compressor being activated for more than the predetermined period of time.

In a sixth aspect, the present invention provides a boiling and/or chilling water unit including: at least one water tank; a control means; a spilled water retention tray beneath the water tank(s); and a water level sensor located in the tray and operatively associated with the control means, wherein the control means is adapted to remove water and/or power supplies from the water unit upon the level sensor indicating the presence of a predetermined level of water in the tray.

In a seventh aspect, the present invention provides a method of operating and boiling and/or chilling water unit, the water unit including: a chilling water tank; a heating water tank; a spilled water retention tray beneath the chilling and heating water tanks; and a water level sensor located in the tray interior, the method comprising the steps of: monitoring the level of water in the tray; and removing the water and/or power supplies to the water unit upon detection of the presence of a predetermined level of water in the tray.

The tray preferably has a volume in excess of the volume of the water tank(s).

In an eighth aspect, the invention provides a boiling and/or chilling water unit including: a mains water inlet; a chilling water tank in controlled fluid communication with the mains water inlet; and/or a heating water tank in controlled fluid communication with the mains water inlet; a first flow restrictor between the mains water inlet and the chilling water tank; and/or a second flow restrictor between the mains water inlet and the boiling water tank.

The flow restrictors are preferably in the form of orifices.

Brief Description of the Drawing

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing: Fig. 1 ; which is a schematic diagram of an embodiment of a boiling/chilling water unit in accordance with the invention.

Detailed Description of the Preferred Embodiment

Fig. 1 shows an embodiment of a combined boiling/chilling water unit 10 according to the invention. The unit 10 is connected to a source of mains water supply 12 at a mains water supply inlet 14. The unit 10 has a chilling water tank 14 and a heating water tank 16 and a control means 18, which is preferably in the form of a printed circuit board with a programmable chip and other associated components.

The chilling water tank is surrounded by cooling coils 20 which are driven by a compressor 22 and a condenser 24. The temperature of the water in the chilling water tank 14 is monitored by a first temperature sensor 26. The sensor 26 communicates a signal indicative of the temperature of the water to the control means 18 which in turn activates and deactivates the compressor 22 and condenser 24 to regulate same.

The water in the heating water tank 16 is heated by a heating element 26. The temperature of the water in the heating water tank 16 is measured by a second temperature sensor 28. The sensor 28 also again communicates a signal indicative of the water temperature to the control means 18 which in turn issues control signals to activate or deactivate the heating element 26 to regulate same.

In a most preferred form, the control means 18 and the associated control logic is similar to that disclosed in the applicant's Australian Patent No. 697832, the relevant portions of which are incorporated herein by cross reference. Directly upstream of the mains water supply inlet 14 is a first flow control valve

30, in the form of an electrically actuated solenoid valve. Upstream of the valve 30 is a double non return valve 32 and then a filter 34. The water supply leaving the filter 34 splits into a supply 36 for the chilling water tank 14 and the supply 38 for the heating water tank 16. The supply 36 passes a second flow control valve 40, also in the form of an electrically actuated solenoid valve, and flow restrictor 42 in the form of an O-ring with a central orifice, before entering the chilling water tank 14. Similarly, the water supply 38 passes through a third flow control valve 44, again in the form of an electrically actuated solenoid non return valve, and flow restrictor 44, again in the form of an O-ring with a central orifice, before entering the heating water tank 16. The O-rings flatten in response to pressure increases in the supply water, which results in reduction of the open cross-sectional (ie. flow) area of their orifices. This provides a fairly constant flow rate through the O-rings regardless of supply water pressure.

The chilling water tank 14 has a tank outlet 47 which is in direct fluid communication with a chilled water free outlet 48 that terminates in a spout assembly 50. A chilled water expansion chamber 52 is also in fluid communication with the chilled water outlet 46 via a venturi 54 (shown in exaggerated size for clarity purposes). The expansion chamber 52 also has a vent 56 to atmosphere that also terminates in the spout assembly 50.

The heating water tank 16 also has a tank outlet 58 in direct fluid communication with a heating water tap outlet 60 that terminates in the spout assembly 50. The heating water tank outlet 58 is also in fluid communication with an adjacent heating water expansion chamber 62 via a venturi 63 (again shown exaggerated). The expansion chamber 62 has a vent 64 to atmosphere that also terminates in the spout assembly 50.

The preferred construction of the heated water expansion chamber 62 is described in the applicants Australian Patent No 675601, the relevant portions of which are incorporated herein by cross reference.

The spout assembly 50 also houses a chilled water actuation switch 66 connected to the control means 18 and a heated water actuation switch 68, with an associated safety switch 70, also connected to the control means 18. The switches 68 and 70 must be activated together for heated water flow, so as to minimise the risk of injury (eg. by scalding) due to incorrect switch selection. The spout assembly 50 also houses a blue chilled water temperature indicator light 72 and a red heated water temperature indicator light 74.

The control means 18 also includes an outlet for the line 76 which is connectable to a building maintenance system 78.

The unit 10 also comprises a spilled water retention tray 80, positioned underneath the tanks 14 and 16 and the other components of the unit 10, and a water level sensor 82 within the tray 80 that communicates a signal indicative of the water level in the tray 80 to the control means 18. The advantages of the above described boiling/chilling water unit 10 and its associated methods of operation and protection will now be described.

Firstly, the control means 18 is adapted to wait for a predetermined period of time after the second or third flow control valves 40 and 44 have been closed before it closes the first flow control valve 30. The predetermined period of time is dependent on the configuration of the components and pipe work between the valves 30, 40 and 44 and is adjusted such that any pressure spikes caused by the closure of the second or third valves 40 and 44 can travel back toward and through the first valve 30 before it is closed. This avoids any pressure spikes damaging the pipe work, non return valve 32, filter 34 or valves 30, 40 and 44. In the boiling/chilling water unit marked by the applicant under the Trade Mark HYDROTAP, the time delay period is approximately 100 milliseconds.

Pressure spikes in the chilling water tank 14 itself are avoided by the provision of the chilled water free outlet 47 and the associated chilled water expansion chamber 52. The provision of the free outlet 47 on the chilled water tank 14 is made possible by the second flow control valve 40 controlling the flow of water into the chilling water tank 14. The successful operation of the second flow control valve 40 without damaging downstream components is made possible by the predetermined delay in the closure of the first flow control valve 30 after the second flow control 40, as discussed above.

Further, the flow rate of water entering the chilling and heating tanks 14 and 16 is controlled by the flow restrictors (orifices) 42 and 44 respectively. This is in contrast to the regulation of pressure utilised in the prior art. By controlling the flow rate, the water leaving the chilled and heated free outlets 47 and 58 can be accurately controlled to the preferred rate of between 1 and 2 litres per minute. This is important as, if the flow rate exceeds this range, splashing can occur which is both inconvenient and dangerous in relation to heated water. If the flow rate falls below this range, the venturi effect that draws water from the expansion chambers 52 and 60 will not function correctly.

The control means 18 also has the capability to monitor the length of time the compressor 22 has been continuously activated without the chilled water switch 66 being activated to cause chilled water flow. Under normal conditions, and without any chilled water in the chilling water tank 14 being replaced by mains temperature water, chilling the water in the chilling water tank 14 takes about 15 minutes. If the compressor has been running continuously for more than this time, without the chilled water switch 66 being activated to cause chilled water flow, then this is an indication that the compressor is not functioning correctly, that the temperature sensor 26 has failed or some other fault has occurred. Accordingly, in the preferred embodiment shown, if the control means 18 senses that the compressor 22 has been continuously activated for more than one hour without the chilled water switch 66 being activated to cause chilled water flow then the control means 18 ceases operation of the condenser 22. The control rneans 18 also closes the valves 30, 40 and 44, thereby removing water supply to the tanks 14 and 16, and then removes the power supply from the water unit 10 to stop any further chilling or water flow to the chilling water tank 14. In addition, the control means 18 can issue a warning or maintenance required signal to the building maintenance system 78 via the line 76. The control means 18 will also cause the blue light 72 in the spout assembly 50 to flash to indicate this failure mode. As an alternative to the above, the control means 18 can be configured to continue to operate the condenser 24 for a predetermined time of, for example, 5 minutes after the operation of the compressor 22 has been ceased. This improves the efficiency of the water unit 10.

As a further safe guard, the control means 18 is configured to provide a similar shut down of the unit 10 upon the water level sensor 82 sensing more than a predetermined level of water in the spilled water retention tray 80. The presence of water in the tray 80 indicates a leak in one of the components of the unit 10 and again the valves 30, 40 and 44 are closed and then the power supply to the unit 10 is terminated so no further chilling, heating or water flow occurs. A warning or maintenance signal can again be sent to the building maintenance system 78 via connection 76 and, in this failure mode, the red light 74 in the spout assembly 50 is caused to flash. Further, to prevent damage to any components nearby (especially below) the unit 10, the tray 80 has a volume in excess of the combined volume of the tanks 14 and 16 so as to be able to capture same.

Although the invention has been described with reference to specific examples, it would be appreciated by those skilled in the art that the invention may be embodied in many other forms. In particular, it should be noted that the valve closure delay time and the compressor running shut off time can be adjusted to suit particular installations and unit configurations.

Claims

CLAIMS :

1. A boiling and/or chilling water unit, the water unit including: a mains water inlet; a chilling water tank in controlled fluid communication with the mains water inlet; and/or a heating water tank in controlled fluid communication with the mains water inlet; a first flow control valve between the mains water inlet and the chilling and/or heating water tanks; a second flow control valve between the chilling water tank and the first control valve; and/or a third flow control valve between the heating water tank and the first control valve; and a control means adapted to close the first control valve a predetermined amount of time after the closure of the second or third flow control valves, wherein the predetermined amount of time is sufficient to allow any pressure spike incident on the second or third flow control valves to travel back towards and through the first flow control valve before closure of same.

2. A unit as claimed in claim 1, wherein the first, second and/or third flow control valves are electrically actuated solenoid valves.

3. A unit as claimed in claim 1 or 2. wherein the unit also includes a first and a second flow restrictor between the second flow control valve and the chilling water tank and the third flow control valve and the heating water tank respectively.

4. A unit as claimed in claim 3. wherein the first and second flow restrictors are orifices.

5. A unit as claimed in anyone of the preceeding claims wherein the chilling and/or boiling water tanks each include a tank outlet connected to an expansion chamber via a venturi opening, the tank outlets leading to respective chilled and heated water outlets.

6. A unit as claimed in claim 5, wherein the water outlets are located in a common spout assembly.

7. A unit as claimed in claim 6, wherein the spout assembly also comprises chilled and heated water flow control switches and temperature indicator lights, all of which being in communication with the control means.

8. A method of operating a boiling and/or chilling water unit, the water unit including: a mains water inlet; a chilling water tank in controlled fluid communication with the mains water inlet; and/or a heating water tank in controlled fluid communication with the mains water inlet; a first flow control valve between the mains water inlet and the chilling and heating water tanks; a second flow control valve between the chilling water tank and the first control valve; and/or a third flow control valve between the boiling water tank and the first control valve; and a control means, the method including the step of closing the first flow control valve a predetermined time after closure of the second or third flow control valves, the predetermined time being sufficient to allow any pressure spikes incident on the second or third flow control valves to travel back towards and through the first flow control valve before closure of the first flow control valve.

9. A chilling or boiling/chilling water unit including: a chilling water tank with a chilled water tank outlet, a chilled water free outlet and a chilled water expansion chamber, wherein the tank outlet is in direct fluid communication with the free outlet and the expansion chamber is in fluid communication with the tank outlet via a venturi opening in the tank outlet.

10. A chilling or boiling/chilling water unit, the water unit including: a control means; a chilling water tank; a compressor connected to cooling coils associated with the chilling water tank and associated with the control means; and a device operable to cause water flow from the chilled water tank, wherein the control means is adapted to remove water and/or power supplies from the water unit upon detection of the compressor being continuously activated for more than a predetermined period of time without the device being operated.

11. A unit as claimed in claim 10, wherein the predetermined period of time is one hour.

12. A unit as claimed in any one of the claims 11 or 12, wherein the water unit can also include the issuance of a failure or service required signal to a building maintenance system upon detection of the compressor being activated for more than the predetermined period of time.

13. A method of controlling a chilling or boiling/chilling water unit, the water unit including: a chilling water tank; a compressor connected to cooling coils associated with the chilling water tank; and a device operable to cause water flow from the chilled water tank, the method including the steps of: monitoring the length of time the compressor has been continuously activated without the device being operated; and removing water and/or power supplies from the water unit upon detection of the compressor being continuously activated without the device being operated for more than a predetermined period of time.

14. A method as claimed in claim 14, wherein the predetermined period of time is one hour.

15. A method as claimed in claim 14 or 15, including the step of issuing a failure or service required signal to a building maintenance system upon detection of the compressor being activated for more than the predetermined period of time.

16. A unit as claimed in claim 10, further including: a spilled water retention tray beneath the water tank; and a water level sensor located in the tray and operatively associated with the control means, wherein the control means is further adapted to remove water and/or power supplies from the water unit upon the level sensor indicating the presence of a predetermined level of water in the tray.

17. A water unit as claimed in claim 16, wherein the tray has a volume in excess of the volume of the water tanks.

18. A method as claimed in claim 13, the water unit further including: a spilled water retention tray beneath the chilling water tank; and a water level sensor located in the tray interior, the method further comprising the steps of: monitoring the level of water in the tray; and removing the water and/or power supplies to the water unit upon detection of the presence of a predetermined level of water in the tray.

19. A boiling and/or chilling water unit including: a mains water inlet; a chilling water tank in controlled fluid communication with the mains water inlet; and/or a heating water tank in controlled fluid communication with the mains water inlet; a first flow restrictor between the mains water inlet and the chilling water tank; and/or a second flow restrictor between the mains water inlet and the boiling water tank.

20. A unit as claimed in claim 19 wherein, the first and second flow restrictors are orifices.