AU657340B2 - A gas booster apparatus for a tank of a solar hot water heater - Google Patents

Description

657340

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (Original) APPLICATION NUMBER:

LODGED:

COMPLETE SPECIFICATION LODGED:

ACCEPTED:

PUBLISHED:

RELATED ART: NAME OF APPLICANT: HARDIE ENERGY PRODUCTS PTY LTD C. C C ACTUAL INVENTOR(S): ADDRESS FOR SERVICE: INVENTION TITLE: KELVIN LORD AND COMPANY 4 Douro Place West Perth WA 6005 "A GAS BOOSTER APPARATUS FOR A TANK OF A SOLAR WATER

HEATER"

ASSOCIATED PROVISIONAL APPLICATION NOS; PK 7622 The following statement is a full description of this invention including the best method of performing it known to me/us:- 2 The present invention relates to a gas booster apparatus for a tank of a solar water heater.

In accordance with one aspect of the present invention there is provided a gas booster apparatus for a tank of a solar water heater comprising a heat exchanger tube arranged to be substantially horizontally disposed, and having a open end and a closed end, a gas burner arranged to be mounted in the heat exchanger tube at a location spaced from the open end thereof, and a baffle plate extending longitudinally of the tube and dividing the tube into first and second portions, the baffle plate extending from a point adjacent the first end of the tube and terminating at a point spaced from the second end of the tube, the burner being located in the first portion of the tube, and means being provided for blowing combustion air into the first portion of the tube and exhausting flue gases through the second portion of the tube.

The present invention will now be described, by way of example, with referenceto the accompanying drawings, in whidh:- Figure 1 is an end elevation of gas booster apparatus of the present invention mounted in a tank of a solar water heater with a flue assembly removed; 999. Figure 2 is side sectional elevation of the gcas booster apparatus of Figvre 1 mounted in a tank of a solar water heater with the flue assembly in place; and Figure 3 is a sectional view of a heat exchange tube of the gas booster apparatus of Figures 1 and 2 along the line 3-3 101 111of Figure 2.

4, IL-4 3 In Figure 1 of the drawings there is shown a gas booster apparatus 10 mounted to a tank of a solar water heater.

The apparatus 10 comprises a gas supply conduit 12 provided with a pressure regulator 14 and a solenoid valve 15. The tank also comprises a thermostat 16 and an anode 17.

The apparatus 10 further comprises an electronic control kit 18 complete with a spark igniter cable (not shown).

The gas booster apparatus 10 and the thermostat 16 and the anode 17 are all mounted within a weather protective enclosure 21.

As can be seen in Figure 2, the apparatus 10 further comprises a substantially hoirizontal heat exchanger tube 22 having an outer open end 23 and an inner closed end 24.

*The tube 22 fits within an aperture in an end of a water storage tank 25 defined by an outwardly projecting flange 26. The tube 22 extends into the water storage tank The tube 22 also has an outwardly extending peripheral flange 28 of complementary shape to the flange 26.

S. Further, ,n the assembled condition as shown in Figure 2, 00 the flanges 26 and 28 are loca-ted proximate to one another and a seal is effected between them by means of a gasket As shown in Figure 3, the tube 22 is divided into a first longitudinal portion 32 and a second longitudinal portion 34 by means of a longitudinally extending vertic aI !affle plate 36 which extends from a point adjacent the open end 23 to a point adjacent to but spaced from the closed end 24. The baffle plate 36 is a diametral fit inside the tube 22. A further b? fle plate 37 of shorter length is also -4diametral fit inside the tube 22 and fits alongside the baffle plate 36. The baffle plate 37 has a burner 40 to be described mounted on it (as can be seen in Figure The baffle plate 37 holds the burner 40 in correct location and allows the burner 40 to be withdrawn for service and refitted correctly.

As can be seen in Figure 2, an extension 38 is provided to the conduit 12. The extension 38 extends into the first portion 32 of the tube 22 for a distance from the first end 23. The gas burner 40 is mounted to an inner end of the extension 38 within the first portion 32 at a location spaced from the first end 23. As can be seen in Figure 2, the gas burner 40 is also upwardly spaced from the lowermost portion of the tube 22 and spaced inwardly from sides of the tube 22, The location of the gas burner 40 within the tube 22 reduces the effects of air turbulence from external wind and reduces flame impingement on internal walls of the tube 22. The partition 37 is slid along the partition 36 until 20 the conduit 12 is adjacent the end of the tube 22 as can be ::seen in Figure 2.

As shown, the gas burner 40 is provided with a spark electrode 44 which is energised as required by the spark igniter cable. The spark igniter arrangement-avoids the need for a pilot flame type ignition.

As can be seen in Figure 3, the second portion 34 contains baffles 46 which provide restrictions to direct hot flue gases onto internal walls 47 of the tube 22.

As shown, the extension 38 and the gas burner 40 are 5 downwardly sloped towards bottom 48 of the tube 22 by a small angle. This small angle may be in the range f:rom 3 to 60 such as about 4 1/20.

Outwardly of the tank 25 the gas booster apparatus is provided with a flue assembly 50 connected to the second portion 34 of the tube 22 via a cone 51. The cone 51 is provided with a baffle plate 53 which aligns with the baffle plate 36 at the open end 23. Further, there is provided a low voltage electrically driven fan 52 which is located and arranged to blow combustion air into the first portion 32 of the tube 22. Further, the fan 52 overcomes air resistance of the substantially horizontal tube 22.

Further, the flue assembly 50 is preferably of the balanced type and arranged for external mounting such that 15 prevailing wind has little effect on burner operation. A particularly preferred form of flue assembly 50 is the go known H cowl design.

Still further, the burner 40 is preferably designed to give a long pencil type flame which does not impinge on internal S 20 surfaces of the tube 22 until combustion is complete. It found th&t the small downward angle of the extension 38 Sand the burner 40 allows the pencil flame to be initially directed downwardly towards the bottom 48 and then to be .turned upwardly by the effects of convection without contacting the bottom 48 so that complete combustion is obtained. This ensures a good degree of efficiency and more reliable operation under high wind conditions.

In operation, the gas booster apparatus 10 of the present invention is operated by supplying gas to the burner -6 from the conduit 12 and the extension 38 and by igniting the gas by means of the spark electrode 44. Further, the fan 50 is energised.

This causes the gas to be ignited into a pencil flame as described above and for the pencil flame to be directed towards the bottom 48 but not to contact the bcttom 48.

Further, the fan 52 ensures that there is an adequate supply of combustion air and that there is a reliable gas flow to the end of the first portion 32 and then out through the second portion 34 to the flue assembly 48 via the cone 51. Thus, the gases in the tube 22 execute a U-turn adjacent the second end 24 of the tube 22 and the flue gases flow outwardly through the second portion 34.

In this way the gas from the burner 40 is completely combusted without impinging on the internal surfaces of the tube 22 and adverse effects from heat exchanger hot spots and from external wind are minimised by the location of the burner 40 and the balanced flue The fan 52 is preferably a DC permanent magnet fan which is reliable, cheap, compact and effective 2or the required duty. The DC motor does not however respond to fan air load. Thus, in order to control the fan, fan operation may be sensed by monitoring electronically the. ent drawn by the DC fan motor providing a conc -x window for correct fan operation.

The electronic control kit 18 supplies power to the thermostat 16. Commencement of operation is delayed until a no air flow condition from the fan 52 is sensed.

The fan 52 is then activated and commences to purge the -7 combustion chamber defined by the tube 22. The gas valve is then opened and sparking commences. As soon as a flame is detected sparking ceases. Operation is then controlled by the thermostat 16.

If no flame is detected after a predetermined time the system locks out and has to be reset.

Further, if the flame fails after the flame has been established then reignition will be attempted automatically. If there is a failure to reignite, the system will be locked out and will require resetting by switching off power for about 10 seconds then reenergising the system.

If the system detects a lack of air flow from fan failure the system will lock out and will require resetting.

9*999 Still further, in order that a user can obtain an i* indication that the system is operating a light may be s* 9 provided at a convenient readily viewable location. The light comes on when the solenoid valve 15 is energised, that is, when the gas booster is actually burning.

o 20 It is envisaged that the gas booster apparatus of the present invention could be retro fitted to a solar water .9 heater tank already provided with an electric booster.

Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope:of the present invention.

Claims (10)

1. A gas booster apparatus for a tank of a solar water heater comprising a heat exchanger tube arranged to be substantially horizontally disposed, and having a open end and a closed end, a gas burner arranged to be mounted in the heat exchanger tube at a location spaced from the open end thereof, and a baffle plate extending longitudinally of the tube and dividing the tube into first and second pa it.n.,the baffle plate extending from a point adjacent the first end of the tube and terminating at a point spaced from the second.end of the tube, the burner being located in the first portion of the tube, and means being provided from blowing combustion air into the first portion of the tube and exhausting flue gases through the second portion of the tube.

2. A gas booster apparatus according to Claim 1, which further comprises a gas supply conduit which is provided with an extension which extends into the first portion of thi tube, and a gas burner mounted to an inner end of the extension at a location within the first portion of the tube spaced from the first end of the tube.

3. A gas booster apparatus according to Claim 2, in which the gas burner is upwardly spaced from a lowermost portion of the tube and is spaced inwardly from sides of the tube.

4. A gas booster apparatus according to Claim 2 or 3, in which the extension and the gas burner are downwardly sloped towards a bottom of the tube.

A gas booster apparatus according to Claim 4, in which S/ the extension and the gas burner are downwardly sloped by 9 an angle in the range from 3 to

6. A gas booster apparatus according to Claim 5, in which the extension and the gas burner are downwardly sloped by an angle of about 4.50.

7. A gas booster apparatus according to any one of the preceding claims, in which the second portion of the tube is provided with baffles which provide restrictions to direct hot flue gases onto the tube.

8. A gas booster apparatus according to any one of the preceding claims, in which an electrically driven fan is arranged to blow combustion air into the first portion of the tube and to exhaust flue gases through the second portion of the tube.

9. A gas booster apparatus substantially as hereinbefore S 15 described with reference to the accompanying drawings.

10. A tank of a solar water heater provided with a gas booster apparatus according to any one of the preceding claims. S* 0 DATED JULY 17 1992 HARDIE ENERGY PRODUCTS PTY LTD By their Patent Attorneys KELVIN LORD AND COMPANY PERTH, WESTERN AUSTRALIA 10 ABSTRACT A gas booster apparatus (10) for a tank of a solar water heater comprising a heat exchanger tube (22) arranged to be horizontally disposed and having a gas burner (40) located in an open end thereof. The heat exchanger tube (22) comprises a partition (36,37) and a fan (52) arrr-ged to blow combustion air past the burner (40) along a first portion of the heat exchanger tube defined by the partition (36,37) and then to return along a second portion of heat exchanger tube. In a preferred embodiment the gas burner (40) is mounted on a downwardly inclined extension (38) so as to reduce contact of the gas flame with walls of Lhe heat exchanger tube (22). *fe 00 2 00 o•g 02 oooo