NZ248494A

NZ248494A - Hot water heater - water pipe passes through heated water

Info

Publication number: NZ248494A
Application number: NZ24849493A
Authority: NZ
Inventors: Gary Owen Thomas Muir
Original assignee: Gary Owen Thomas Muir
Priority date: 1993-08-25
Filing date: 1993-08-25
Publication date: 1996-11-26

Description

<div class="application article clearfix" id="description"> 2484* COGNATE £!<», 250 Lt Patents Form No. 5 Our Ref: PZ500576 HEW ZEALAND PATENTS ACT 1953 Complete After Provisional Nos. 248494 and 250222 Filed: 25 August 1993 and 17 November 1993 COMPLETE SPECIFICATION WATER BEATING MEANS I, GARY OWEN THOMAS MUIR, a citizen of New Zealand of 54 Tapu Road/ Huapai, Auckland, New Zealand hereby declare the invention, for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: - 1 - -.251UZ2 248494 This invention relates to water heating means and, in particular, although not necessarily solely, water heating means providing hot water at mains pressure from a hot water source associated with a wet back stove or independent boiler. Conventional water heating means such as hot water cylinders sometimes incorporate attachments so that the water may be heated using heat transfer means associated with a wet back stove, independent boiler or similar apparatus. Such apparatus provides hot water at low pressure to the taps and other appliances throughout the house. Mains pressure systems for providing hot water are also known. An example of such a system is provided in New Zealand patent No. 112967 in which a pipe coil carrying water at mains pressure is placed inside a cylinder of thermostatically controlled heated water and allowing the transfer of heat from the water within the cylinder to heat the water within the pipe coil. The outlet of such a system can provide hot water at mains pressure to the plumbing fittings throughout the house. Another similar system is shown in New Zealand patent No. 117216. .25 0*22 248494 It has been found that these systems are not readily adaptable to connection to wet back stoves or independent boilers. The prior art mains pressure systems rely on thermostatic control of the water temperature within the cylinder to prevent overheating of the cylinder and/or the pipe coil within the cylinder. The incorporation of fittings to link a wet back stove or independent boiler to such systems removes the ability of the thermostat to control the upper temperature of the heated water within the cylinder when the wet back stove or independent boiler is providing the heating source. Therefore, it is necessary to vent both the water cylinder itself and provide some control on the pipe coil so that the pressures within the pipe coil do not increase to dangerous levels. Therefore, it is an object of the present invention to overcome some of the disadvantages of the prior art and/or at least provide the public with the useful choice. Accordingly, in a first aspect, the invention consists in a water heating means comprising: a water tank connectable to a water supply such that in use said water tank may be filled with water; -250*22 248494 - 4 connection means on said water tank such that, in use, water in said tank may be circulated to an external heating source; a water containing means within said tank which may allow heat transfer from heated water in said water tank to heat water within said water containing means; an inlet to said water containing means for attachment to a cold water supply at mains pressure; an outlet from said water containing means to provide, in use, heated water at mains pres sure; and pressure control means associated with said water containing means to release pressure from said water containing means should the pressure within said water containing means exceed a set level. Accordingly, in a second aspect, the invention consists in a water heating means comprising: a heat exchange unit comprising a first fluid containing part and a second fluid containing 250*22 248494 - 5 part and suitable for heat exchange between fluids held in said first and second parts; said first fluid containing part having connection means such that said fluid in said first part may be circulated past an external heating source to heat said water in said first part; said second fluid containing part having an inlet for attachment to a cold water supply at mains pressure; an outlet from said second fluid containing part to provide, in use, heated water at mains pressure; and, pressure control means associated with said second fluid containing part to release pressure from said second fluid containing part should the pressure within said fluid containing part exceed a set level. The preferred embodiments of the invention may be described with reference to the following drawing in which: 250*22 248484 — 6 — Figure Is is a cross-sectional elevation of a water heating means in accordance with the invention. Referring to Figure 1, a water heating means 1 is provided comprising a water tank 2 capable of holding a body of water. The water tank 2 is also provided with an inlet 3 capable of connection to water supply source 4. Where this water supply source 4 is provided at mains pressure, a pressure reducing valve 5 may also be provided to provide the supply to the water tank at lowered pressure. The water tank 2 as shown in Figure 1 has an inlet and outlet 7 and 8 for connection to a wet back stove, heater or independent boiler or similar external heating source so that the body of water within the tank 2 may be heated. A water containing means such as a pipe coil 9 is provided within the tank 2 such that water within the water containing means 9 may be heated by heat transfer from the heated surrounding water within the water tank 2. This water containing means may be of any suitable type to provide sufficient heat transfer such that water flowing from an inlet 10 to said water containing means 9 and an outlet 11 from -£50*22 248 4^4 said water containing means 9 is heated to a desired temperature. In this embodiment, the water containing means 9 comprises a copper pipe coil such that the length of copper pipe provided within the water tank 2 is much greater than the largest dimension of said water tank 2. Pressure control means 12 are provided in association with the water containing means 9. In this preferred embodiment, the pressure control means comprises a cold water expansion valve on the inlet to the water containing means 9. This expansion valve will allow cold water to be released out an associated drain 14 should the pressure within the water containing means 9 exceed a safe level for integrity of the system. Although a similar safety valve could be incorporated on the outlet 11 rather than the inlet 10, such a valve would drain off hot water and draw further cold water into the water containing means 9. This can lead to thermo siphoning through the water containing means 9 and lead to an unnecessary waste of hot water. A vent 15 should also be incorporated within the system to allow for the venting of pressure from within the water tank 2. As this water tank 2 is 250*22 248494 - 8£ kept at a pressure much less than mains pressure in this preferred embodiment, the vent may be nothing more than a vertical tube extending from the top of the water tank 2 and through the roof of the house or structure in which the water heating means is incorporated. The outlet 11 may lead to a tempering valve 16 which also receives a feed from the cold water supply 4 so that the resultant outlet 17 from the tempering valve delivers hot water at mains pressure at a selected desired temperature controlled by the tempering valve 16. As shown in Figure 1, the water tank 2 may be incorporated within an outer tank 18 and suitable insulation material 19 may surround the water tank 2 within the outer shell 18. An element and thermostat 20 may be incorporated in the water tank 2 to control the heating of the water within the tank 2 when the wet back stove or independent boiler is not in operation and no heat has been supplied through that heating means. The thermostat forming part of the combination element and thermostat 20 is provided to control and limit unnecessary use of the element in heating water within the water tank 2. It does not - 9 - control the temperature within the water tank 2 when the wet back stove or independent boiler is in operation and being used as the primary heating source. A variety of valves 21, 22 and 23 may be provided throughout the system to isolate the various components of the system for maintenance purpose,.'' , etc. In use, water within the water tank 2 may be initially be heated using either the element and thermostat 20 or by use of the connection 7 and 8 to a secondary heating source such as a wet back or an independent boiler. As water is drawn from the outlet 11 from the water containing means 9, water will be drawn into the water containing means 9 through the inlet 10 attached to a cold water supply. As water flows from the inlet 10 to the outlet 11, the water is heated by heat transfer from the surrounding water held within the water tank 2. Therefore, the water supplied to the outlet 11 is at a desired heated temperature. Further adjustment of this water temperature can be made through the use of the tempering valve 16 introducing water from a water supply 4 to temper the temperature of the final hot water supply 17. 250222 "10*5A2 22 ^8 When all the taps are turned off and the wet back or similar external heating source is in operation, the temperature within the water tank 2 may continue to increase and hence the pressure within the tank 2 will also increase. To release this pressure, the vent 15 may operate to vent water or gas from within the water tank 2 at its top and thereby reducing the pressure within the tank 2. As the temperature increases within the water tank 2, a corresponding increase in temperature occurs within the water containing means 9. As this temperature increases, causing an increase in pressure, the expansion valve 12 will allow for the leakage of water through the valve once the pressure reaches a predetermined limit. This water can be taken away through drain 14. Thus, the system provides hot water at a mains pressure while using a substantially unregulated heat source such as a wet back stove or independent boiler to assist in the heating of water within the water tank 2. The system combines a low pressure surrounding body of water with a mains pressure water containing means that may heat water through heat transfer from the surrounding body of water. Appropriate safety valves have been incorporated to release pressure from both within the water tank and the water containing means 9. In an alternative embodiment, alternative heat exchange means are used in place of the water tank 2 and coil 9 as described in the previous embodiment. The alternative heat exchange unit could comprise a stainless steel tank or similar manufactured to hold fluid at mains pressure such that the tank itself may be used as the mains pressure fluid containing part being a second fluid containing part and a first fluid containing part which may even still comprise a coil similar to coil 9 in Figure 1 which is connected to a wet back stove or other external heating source such as a solar heating means. Pressure valves will still be incorporated as described in the previous embodiment with a pressure control means preferably on the cold water inlet to the second fluid containing part containing the water to be heated and, preferably, a pressure release on the first fluid containing part containing the fluid passing by the external heating source. In general, any heat exchange unit containing two fluid containing parts whereby one fluid containing part is constructed to operate at mains - 12 - pressure and another fluid containing part connectable to an external heating source can used in conjunction with the pressure control gieans of this invention. Where in the foregoing description reference has been made to specific components or integers of the invention having known equivalents then such equivalents are herein incorporated as if individually set forth. Although this invention has been described by way of example and with reference to possible embodiments thereof it is to be understood that modifications or improvements may be made thereto without departing from the scope or spirit of the invention. 248494 25 0 2 22 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 24 8494 250222 WHAT WE CLAIM IS: 1. A water heating means comprising: a water tank connectable to a water supply such that in use said water tank can be filled with water; connection means on said water tank such that, in use, water in said tank can be circulated to an external heating source; a water containing means within said tank which may allow heat transfer from heated water in said water tank to heat water within said water containing means; an inlet to said water containing means for attachment to a cold water supply at mains pressure; an outlet from said water containing means to provide, in use, heated water at mains pressure; and pressure control means associated with said water containing means to release pressure from said water containing means should the 14 248494 pressure within said water containing means exceed a set level. A water heating means as claimed in claim 1 wherein said external heating source comprises a wet back stove, heater or independent boiler. A water heating means as claimed in claim 1 or claim 2 wherein the pressure control means is provided on said cold water supply inlet to the water containing means. A water heating means as claimed in claim 3 wherein said pressure control means comprises a cold water expansion valve. A water heating means as claimed in any one of the preceding claims wherein a further pressure control means is provided on said water tank. A water heating means as claimed in any one of the preceding claims wherein an element and thermostat are also provided to heat water within said water tank when said external heating source is not in operation. _ 152 4 8 4 9 4 250 2 2 2 7. A water heating means as claimed in any one of the preceding claims wherein said outlet from said water containing means leads to a tempering valve, said valve connected to a cold water supply such that the hot water outlet from said valve is at a controlled temperature. 8. A water heating means comprising: a heat exchange unit comprising a first fluid containing part and a second fluid containing part and suitable for heat exchange between fluids held in said first and second parts; said first fluid containing part having connection means such that said fluid in said first part can be circulated past an external heating source to heat said water in said first part; said second fluid containing part having an inlet for attachment to a cold water supply at mains pressure; an outlet from said second fluid containing part to provide, in use, heated water at mains pressure; and, * - 16 - 248494 2i>u^22 pressure control means associated with said second fluid containing part to release pressure from said second fluid containing part should the pressure within said fluid containing part exceed a set level. 9. A water heating means as claimed in claim 8 wherein said external heating source comprises a wet back stove, heater or independent boiler. 10. A water hating means as claimed in claim 8 wherein said external heating source comprises a solar heating means. 11. A water heating means as claimed in any one of claims 8 to 10 wherein said pressure control means is provided on said cold water supply inlet to said second fluid containing part. 12. A water heating means as claimed in claim 11 wherein said pressure control means comprises a cold water expansion valve. 13. A water heating means as claimed in any one of claims 8 to 12 wherein a second pressure control means is provided on said first fluid containing part. 248494 - 17 - 14. A water heating means as claimed in any one oJ claims 8 to 13 wherein an element and thermostat are provided to heat water within said first fluid containing part when said external source is not in operation. 15. A water heating means as claimed in any one of claims 8 to 14 wherein said outlet from said first fluid containing part leads to a tempering valve, said valve also connected to a cold water supply such that the heated water from said valve is at a controlled temperature. 16. A water heating means substantially as hereinbefore described with reference to the accompanying drawings. GARY OWEN THOMAS MUIR by his attorneys BALDWIN, SON & CAREY lh:PT0517512 r ~ 1 ; MT ... </div>