AU644908B2 - A water heating arrangement - Google Patents

Description

644908 38969 PJW:LL P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: c WAYNE JOSEPH CARN AND SHIRLEY ANN CARN Actual Inventors: WAYNE JOSEPH CARN AND SHIRLEY ANN CARN Address for Service: COLLISON C0.,117 King William Street, Adelaide, S.A. 5000 Invention itle: CA WATER HEATING ARRANGEMENT NDetails of Assciated Provisional Applications: PK3089 dated 31st October 1990 WAYNE JOSEPH CARN AND SHIRLEY ANN CARN Actual llowing statement is a full description of this invention,ors: includiWAYNE JOSEPH CARN AND SHIRLEY ANN CARNown to us: Address for Service: COLLISON CO.,117 King William Street, Adelaide, S.A. 5000 Invention Title: A WATER HEATING ARRANGEMENT Details of Associated Provisional Applications: PK3089 dated 31st October 1990 The following statement is a full description of this invention, including the best method of performing it known to us: This invention relates to the heating of water by heat exchange with flue gases from a fuel fed heater, and in particular to an arrangement to control the heating.

It is known to use heat emanating from flue gases of heaters such as combustion stoves to heat water for domestic use, either as a sole source or as an auxiliary source of heat. Heat is exchanged with water in a heat exchanger located in the path of flue gases. Water passing through the heat exchanger is heated and then either pumped or moved by reason of a 1 0 thermal syphon to a storage tank.

The temperature of the flue gases especially in solid fuel fed fires can be extremely high, and thus the temperature obtained by water can very quickly rise, causing the water to become too hot for use, and more importantly can 1 5 be caused to either boil or at least expand to such an extent so as to cause damage to the hot water systems.

To prevent overheating of water a diverter can be used to divert the flue gases away from the heat exchanger or a closure may be provided to shutoff access to the heat exchanger. However, the mechanisms for triggering the diversion of flue gases away from the heat exchanger are not always reliable, and the results of such failure can be catastrophic. It is thus an object of this invention to provide for an arrangement for the heating of water by heat exchange with flue gases of a fuel fed heater with the provision of a 2 5 safety override.

o• Thus the invention could be said to reside in an arrangement for heating water held within a storage container by heat exchange with flue gases emanating from a fuel fed heater said arrangement including, 3 0 a heat exchanger located within a heat exchange channel defined within a flue pipe, a closure supported for movement between a closed position and an open position, in the closed position said closure blocking passage of flue gases into the heat exchange channel and in the open position maintaining the heat exchange channel open, regulating means including a first biasing means biasing said closure to the open position, said regulating means further including a first thermo-responsive means adapted in response to heating of water within an 3 inlet pipe to move the closure towards the closed position against said first biasing means to thereby regulate the influx of flue gases from said heater into said heat exchange channel, said inlet pipe communicating between an inlet of the heat exchanger and the water storage container, and safety override means including a second thermo-responsive means adapted to release said first biasing means on the attainment of a set temperature in an outlet pipe, said outlet pipe communicating between an outlet of the heat exchanger and the water storage container, said safety override means including a second biasing means adapted, to shift said 1 0 closure to the closed position, on the release of the first biasing means.

Thus the safety override means is coupled to the out!et pipe of the heat exchanger and consequently is linked to the portion of the arrangement which is most sensitive to increase in heat. Under normal operations the 1 5 amount of flue gas passing through the heat exchange and the heat exchanger is regulated by the temperature in the inlet pipe to the heat exchanger, directly reflecting the temperature of the water in the storage container and communication with the heat exchanger.

2 0 In preference, the flue pipe is forked, the heat exchange channel and the bypass channel diverging oppositely from a plane extending longitudinally with the flue, and the closure comprises a flap supported so as to be pivotable about an axis within the plane and at an apex of the fork.

Preferably the second biasing means is an overweight to the flap. The flap S2 5 thus, in its inherent structure, is biased to close the heat exchange channel and, with no mechanical sophistication liable to breakdown, would tend towards the closed position. This very basic flap closure arrangement is found to be extremely reliable.

In preference, the operating means includes a pivotable arm a first end portion of said pivotable arm connected with said S* closure so that movement between a first and second position effects a movement of said closure between the open position and the closed position respectively, 35 said end portion biased to the first position by the first biasing means said first thermo-responsive means comprising a chamber and having thermally expansive material therein, in thermal communication with said water inlet pipe, and including means adapted in response to increasing temperature within said inlet pipe to bear against a second portion of said arm so as to move said arm towards the second position.

Preferably said first biasing means is a spring connected from a first end to the arm and from a second end to a catch, the second thermo-responsive means including a thermaliy expansive probe and including means extendible from the probe and soc located that at a pre-set temperature of water within said outlet the catch is released by the extendible means.

In one form said heat exchanger comprises a body comprising two substantially concentric sleeve shaped sides closed over at either end and defining therebetween a sleeve shaped chamber, the sleeve shaped 1 5 chamber being substantially in line with the first flue channel.

Preferably the sleeve shaped body includes a fin extending from a flue proximal portion of the body towards the closure.

0 In another form the heat exchanger can comprise a helically coiled tube.

9 S.

For a better understanding the invention will now be described with reference to a preferred embodiment and with the assistance of the aa* drawings in which: FIGURE 1 is a plan view of the back of a flue including a heat exchanger and the inlet and outlet to the heat exchanger, 99 FIGURE 2 is a close up view showing the operating control and safety 30 override, *1 9 S* FIGURE 3 is a close up view from the side showing the operating control and safety override, and O D3 5 FIGURE 4 is a plan view from the front.

The embodiment described below is intended for solid fuel combustion stoves having a flue pipe extending upwardly. The flue pipe 1 is forked with a heat exchange channel 2 and a by-pass 3 extending oppositely of a longitudinally central plane 4, and the heat exchange and the by-pass join together again higher up.

Within the heat exchange channel is a heat exchanger 5 with an inlet 6 and an outlet 7 coupled respectively to an inlet water pipe 8 and to an outlet pipe 9 both connected with a storage container (not shown) to allow for the 1 0 heating of water coltained in the storage container.

The flue pipe is made to a standard flue pipe length and thus is easily fitted.

The heat exchanger 5 is in the form of a copper sleeve-shaped water jacket 1 5 with a 90mm centre bore 10 and a 25mm clearance from the inside surface of the flue pipe the latter clearance beinq to facilitate cleaning. The water jacket is formed between two copper sleeves both concentric with one another and joined together at both ends to define therein the water jacket.

The inner sleeve 11 extends upwardly beyond the outer sleeve to form an 0 upper fin and extends downwardly to form a lower fin 12 the lower fin is greatly extended. These fins extend the area over which heat is captured from the flue gases and hence the area made available for exchange with water inside the jacket. The lower fin also allows for the drainage of S resinous material that condenses on the heat exchanger thereby aiding the self-cleaning nature of the heat exchanger.

A closure flap 13 is supported so as to be pivotable about an apex of the fork 14 leading to the heat exchange channel and the by-pass. The closure flap 13 can thus pivot between metal rings 15 and 16 and thus between a closed 3 0 position where the flap lies against metal ring 15 so that the by-pass is fully opened with the heat exchange channel being closed. In an open position the flap 13 lies against the metal ring 15 and the first channel is fully opened with the by-pass 3 closed. Thus metal ring 15 extends inwardly into the heat exchange channel and around the entire circumference of that section of the '3 5 flue pipe, thereby providing a reasonable seal for flue gases. Similarly with metal ring 16. Metal rings 15 and 16 are appropriately fastened to the flue pipe.

Extending upwardly from the flap 13 is a counter balance 17 in the form of an arrow head, the weight of the counter balance 17 being the same or very similar to that of the flap 13. Extending toward the by-pass 3 from axis 14 is an over-weight 20. Thus on its own this arrangement of flap 13, counter balance 17 and over-weight 20, the flap is biased towards the closed position such that the heat exchange channel is closed to flue gases.

The flap is coupled to an operating mechanism by means of lever arm 18 connected by a strong wire 19 to pivotable arm 38. Pivotable arm 38 is in 1 0 the form of an elongate bar which is supported so as to be pivotable about an axis 21 located at the central portion of the pivotable arm 38. The first end of pivotable arm 38 is coupled by stiff wire 19 to the flap and a second end is coupled via a spring 22 to a catch arrangement 23 located on the outlet pipe 9. Wire extensions extend between the spring 22 and the second 1 5 end of the pivotable arm 38 as well as between the spring 22 and the catch 23. The catch 23 anchors the wire extension 24 into place and thus spring 22 biases the flap to the open position with respect to the heat exchange channel. The bias of the spring is thus greater than the bias of the overweight a2 0 •0 The catch arrangement is best seen in Figure 3 and comprises a ring fitted over a lug 26, which is fastened to the outlet pipe. An expansion probe S 27 is located against the outlet pipe. The expansion probe is of the sort which has a thermally expanding plastics material within it and extending from one end 28 such that with increasing temperature the thermally expansive plastics material gradually moves ring 25 gradually toward the free end of the lug 26. This arrangement is so positioned that at a S• predetermined temperature the ring 25 is caused to disengage from the lug 26, allowing the natural bias of counter weight 22 to shift flap 13 to the 30 closed position and deny access by flue gases to the heat exchange channel. The predetermined temperature can be in accordance with the tolerances of the system.

A warning tag 29 is affixed to the wire extension 24 so that the position of the S• *3 5 tag is visible to indicate whether the safety override has operated or not, and its position coincides with a window (not shown) through housing Housing 30 provides a heatshield and encloses inlet pipes outlet pipes and a considerable proportion of the workings of this water heating arrangement.

The position of the flap 13 is adjusted to response the temperature of the inlet water, and means to operate the flap include a cylindrical chamber against the inlet pipe which is filled with oil. The walls of the chamber are thermally conducting. The cylinder includes at a lower part a cylinder sleeve 32 with a piston 33 having O rings 34 to give a seal between the piston and the inside of the lower part 33 of the cylinder. An increase in temperatuirl of water within the inlet causes expansion of oil within the cylinder 31 and drives the piston 33 downwardly. This then works against the biasing spring 1 0 22, bearing against the pivoted lever arm 20 to pull the flap lever arm 18 upwardly and thereby draw the flap toward the closed position. A cap 35 is screw fitted to the top of the expansion cylinder 31 to allow for filling of the cylinder with oil, with replacement oil as necessary.

1 5 A hot water drain cock 36 is level with a lower portion of the heat exchange water jacket to allow for drainage of the entire system. The heating arrangement is set up as a water syphon and thus the relatively cool inlet water is fed in at a lower part of the heat exchanger and water by reason of its heating, moves upward to the outlet through the outlet pipe and to an .2 0 upper portion of the water container the inlet pipe is lead off from the water storage container from a lower part to thereby complete a circulation path for the water.

4.' Cleaning access ports 34 are provided to clean the inside of the flue and are fastened by means of wing nuts A slot 37 in the housing is positioned so as to reveal the position of the arrow shaped counter weight 17 and gives an indication of the extent to which the flap is opened, and thus an indication of direction of travel of the flue gases.

Gas The above then is a description of the preferred embodiment of the 0 invention.

Self-evidently the invention can be adapted for use with any heating g3 5 arrangement which creates flue gases sufficiently hot to heat water in a heat exchanger.

It is further to be understood that although this embodiment does show a bypass flue pipe which leads back on to itself to form a flue pipe with one opening at both ends the by-pass may lead to a separate outlet, or alternatively no by-pass may be needed in the event that what is required is a decrease in air flow through the fuel fed fire as less heat is required heat already hot water. In this latter form therefore not only is the access to the heater diminished by a closure of the heat exchange channel but the intensity of the fire is also somewhat diminished.

1 0 Further it is to be understood that the heat exchange may not necessarily be in the form of a jacket, and can be in the form of a copper coil helically wound to fit within the first channel of the flue pipe. In this form it is desirable to have the heat exchange coil made of copper tubing and preferably the size less than the inlet pipe and the outlet pipe and preferably the inlet pipe 1 5 and outlet pipe are 25% larger than the coil pipe.

Whilst the preferred embodiment described may be used in mains pressure water systems, it is equally applicable to lower pressure hot water suppliers such as may be gravity fed ceiling units. The unit may naturally be 0 supplemented with solar water heating, or alternatively gas or electric heating units.

Various features of the invention have been particularly shown in describe in connection with the illustrated embodiment of the invention, however it must be understood that these particular arrangements merely illustrate and that the invention is to be given its fullest interpretation within the terms of the appended claims.

*6 00 6 o 0050 ••Qo 0•° 5606o

Claims (9)

1. An arrangement for heating water held within a storage container by heat exchange with flue gases emanating from a fuel fed heater said arrangement including, a heat exchanger located within a heat exchange channel defined within a flue pipe, a closure supported for movement between a closed position and an open position, in the closed position said closure blocking passage of 1 0 flue gases into the heat exchange channel and in the open position maintaining the heat exchange channel open, regulating means including a first biasing means biasing said closure to the open position, said regulating means further including a first thermo-responsive means adapted in response to heating of water within an inlet pipe to move the closure towards the closed position against said first biasing means to thereby regulate the influx of flue gases from said heater into said heat exchange channel, said inlet pipe communicating between an inlet of the heat exchanger and the water storage container, and safety override means including a second thermo-responsive means adapted to release said first biasing means on the attainment of a set temperature in an outlet pipe, said outlet pipe communicating between an outlet of the heat exchanger and the water storage container, said safety override means including a second biasing means adapted to shift said closure to the closed position on the release of the first biasing means. 25 i

2. An arrangement for heating water as in claim 1 wherein said flue pipe includes a by-pass channel, wherein the closure in the closed position maintains said by-pass channel open, and in the open position blocks said by-pass channel.

3. An arrangement for heating water as in claim 2 wherein said flue pipe is forked, the first channel and said by-pass channel diverging oppositely from a plane extending longitudinally with the flue, said closure comprising a flap supported so as to be pivotable about an axis within said •e t35 plane and at the apex of the fork, and wherein said second biasing means is an over-weight biasing said flap to the closed position. 4 •o I I

4. An arrangement for heating water as in any one of the preceding claims wherein said operating means includes a pivotable arm a first end portion of said pivotable arm connected with said closure so that movement between a first and second position effects a movement of said closure between the open position and the closed position respectively, said end portion biased to the first position by the first biasing means said first thermo-responsive means comprising a chamber and having thermally expansive material therein, in thermal communication with said water inlet pipe, and including means adapted in response to increasing temperature within said inlet pipe to bear against a second portion of said arm so as to move said arm towards the second position.

5. An arrangement for heating water as in claim 4 wherein the thermally expansive material of the first thermo-responsive means is oil, and said chamber is a cylinder said first thermo-responsive means including a piston driven by the expansion and contraction of the said oil, a free end of SO.. the piston bearing aga.nst second portion of the pivotable arm. 0. 0

6. An arrangement for heating water as in either claim 3 or 4 wherein said first biasing means is a spring connected from a first end to the arm and ~from a second end to a catch, o'0said second thermo-responsive means including a thermally expansive probe and including means extendible from the probe and so located that at a pre-set temperature of water within said outlet the catch is released by the extendible means. O°,

7. An arrangement for heating water as in any one of the preceding °.003 0 claims wherein said heat exchanger comprises a body comprising two 00•0 substantially concentric sleeve shaped sides closed over at either end and ~defining therebetween a sleeve shaped chamber, said sleeve shaped .ho. chamber being substantially in line with the first flue channel. 5

8. An arrangement for heating water as in claim 7 wherein said sleeve shaped body includes a fin extending from a flue-proximal porticn of said body towards said closure. 11

9. An arrangement for heating water as in any one of the preceding claims wherein said inlet is at a lower portion of said exchanger and said outlet is at an upper portion of said exchanger and adapted to be connected with said water storage container so that in use a heat syphon effect is created. An arrangement for heating water held within a storage container by heat exchange with flue gases emanating from a fuel fed heater substantially has described in the specification with reference to the 1 0 illustrations. Dated this 30th day of October 1991 WAYNE JOSEPH CARN and SHIRLEY ANN CARN By their Patent Attorneys, COLLISON CO. O* 9 0 S t •S C* ABSTRACT A water heating arrangement for heating water in a storage tank by flue gases from, for example fires. The arrangement comprises a heat e'changer located with a flue pipe, and a closure for shutting of the flue pipe, donstream of the heat exchanger, and operated by a regulator sensitive to water temperature. The regulator biases the closure to an open position, and a thermoresponsive adjuster, connected with an inlet to the 1 0 heat exchanger, to shut the closure. A safety override mechanism is connected with an outlet of the heat exchanger, to disconnect the regulator and to bias the closure shut where a predetermined temperature is reached. 9* S 5 4 S **o