AU615227B2 - Heating apparatus - Google Patents

Description

V II II PATENTS ACT COMPLETE SPECIFICAN1 "27 OR I G I NA L (FOR OFFICE USE) Class Int Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Related Art: 00: Name of Applicant(s): Address of Applicant(s): 5.2 l. e e Io n 9 Ra, ke a, i c .r i a 1P2 Actual IN NE Address for Service: PATENT ATTORNEY SERVICES 26 Ellingworth Parade, Box Hill, Victoria 3128 M C2,, lt c4 naiZ for the invention entitled: HEATING APPARATUS The following statement is a full description of this invention, including the best method of performing it known to me HEATING APPARATUS This invention relates to heating apparatus such as for use in domestic and commercial heating situations.

Known domestic and commercial heating apparatus include wall furnaces an( radiant space heaters. Wall furnaces are space heaters which are designed to be mounted on a wall. They are narrow, and consequently tall, to fit between wall studs when recessed fully or partially into a wall cavity. A wall furnace includes a burner arrangement and a heat exchanger to collect combustion products from the burner arrangement and a fan for forcing air over the heat exchanger to heat the same, the air being expelled into the space to be heated. This kind of heater can be operated under thermostatic control to heat air in the space to a desired temperature and maintain it generally at that level. A disadvantage of this kind of convective heater is that S it can be relatively slow to raise the temperature in a room to S a comfortable level, particularly when the room is initially relatively cold. Wall furnaces, like other convective type heaters must heat large volumes of air, without creating cold 26. draughts, before a comfortable condition is reached. They cannot be readily used for local or "spot" heating.

A radiant space heater can be quite effective in providing comfortable conditions for occupants even though the room temperature may be relatively low. Because radiant heat can be felt directly by an occupant, the occupant can feel comfortable in a room having a much lower air temperature. However a oo 0 S disadvantage of radiant heaters is that they can produce 0 G 2 uncomfortably hot conditions near to the heater and/or allow uncomfortably cold conditions at a distance. Radiant heaters typically have manual selection of their radiant heat output rate unlike convective heaters which typically have thermostatic control. This is because thermal comfort is also dependent on the level of radiant heat energy reaching a person. An air thermostat in the heating appliance could not judge these conditions. A thermostat would turn the radiant burners up or down in response to a small shift in the air temperature and make the users uncomfortable. Radiant heat can be manually selected for comfortable and efficient heating of specific zones in front of the heater.

Radiant space heaters have been known to be provided with fans for blowing air across the components carrying combustion products from the burners to the flue so as to thereby effect S some convective heating of the space. However it has not been possible even with these heaters to optimise the balance between convective heating of the room air and radiant heat output, For example, setting the heater to operate at a level at which the radiant heat output is at a comfortable level for room occupants relatively near to the heater can lead to very slow convective heating of the room to reach the desired room temperature It is an object of the present invention to provide a heating apparatus enabling both radiant and convective heating in a relatively efficient and controllable manner, According to the present invention there is provided a 000 heating apparatus for heating a space to be occupied, the heating apparatus including a combustion chamber where combustion of a fuel occurs, a radiant heat source associated r-.aru II I u

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a a ooo aa o n eoo o oo o oo a a I a1 with the combustion chamber and operative to be heated by the combustion of the fuel and to provide a radiant heat output to heat the space where the heating apparatus is installed, a heat exchanger arranged and operative to collect combustion products from the combustion chamber and to convey those combustion products to a discharge point, air moving means arranged and operative to move air over heating surfaces of the heat exchanger so that the air is heated thereby, the heated air being expelled in use into the space to thereby provide a convectve heat output to heat the space, and selectively :00 operable heat control means for enabling a user to control the 0 radiant heat output at least partially independently of the o convective heat output or vice versa.

o0 Preferably the selectively operable heat control means includes a radiant heat controller for enabling a user to control the radiant heat output at least partially independently 000 o of the extraction of heat from the heat exchanger by the air °a Smoving over the heating surfaces whereby the user can select a desired radiant heat output level while maintaining a generally independent air heating effect within the space caused by heated air being expelled by the air moving means into the space.

In the preferred embodiment the combustion chamber includes a radiant burner arrangement, the radiant burner arrangement being operatively associated with radiant elements comprising the radiant heat source. The radiant elements may comprise for example ceramic elements which are heated by combustion of the fuel by the radiant burner arrangement, the ceramic elements radiating a substantial amount of heat into the space. The ceramic elements may comprise for example burner tiles which have fuel passages therethrough, the fuel undergoing combustion S 4 A4 '0- II as it passes through the passages and emerges From the passages, the combustion of the fuel heating the ceramic tiles to cause them to radiate heat. Preferably the combustion products from the radiant burner arrangement are collected by the heat exchanger and conveyed to the discharge point.

A selectively operable convective heat controller is preferable for enabling a user to control the convective heat output at least partially independently of the radiant heat output, the convective heat controller enabling user control of the operation of the air moving means and/or control of the temperature of the heating surfaces of the heat exchanger over which the air is moved by the air moving means. The convective heat controller preferably includes a thermostat which the user can set to the desired temperature of air within the space, the air moving means and/or the heat exchanger surface temperature being responsive to the thermostat. By controlling the o Q combustion chamber for example the heat exchanger surface ootemperature can be controlled.

The combustion chamber preferably includes a convective 21J' burner arrangement and an independent radiant burner arrangement, the radiant burner arranyement being operatively associated with the radiant heat source, the convective burner arrangement being operative to burn fuel, the heat exchanger being arranged and operative to collect combustion products from the convective burner arrangement and to pass those products to the discharge point with little of the heat of combustion S generated at the convective burner arrangement being radiated to 00 IC a g 8 the space to be occupied. In the preferred embodiment having independent radiant burner and convective burner arrangements it T- i is possible therefore to provide for largely independent control of the radiant and convective heat output of the heating apparatus. The combustion products from both the radiant and convective burner arrangements are preferably collected by the heat exchanger so as to enable relatively efficient heat extraction from the combustion products.

The air moving means may be operative to move air over the heating surfaces of the heat exchanger in a counter flow direction, i.e. in a generally coldest air first reaches the before the discharge point, t towards the hotter surfaces of combustion chamber. This is t extraction with a relatively Preferably the air moving mea preferably being located at a apparatus and preferably below this location of fan, the fan ma into the heating apparatus at an downwards direction so that the heating surfaces immediately he air being passed downwardly the heat exchanger nearer to the he most efficient method of heat simple upright heat exchanger.

ns comprises a fan, the fan lower portion of the heating the comhustion chamber. '"ith y be either arranged to draw air upper portion of the heater and draw the air downwardly over the heat exchanger, through the fan and thence out of the front of the heater. Alternatively the fan may draw in air from the front bottom of the heating apparatus, move the air upwardly through an upright passage which opens at the upper portion of the heating apparatus, the air emerging from the upper end of the passage then being directed downwardly over the heat exchanger. The fan for example may comprise a tangential blower although other types of fans may be used.

The outlet heating heating apparatus operative to pass apparatus, the may further include a rear heated air heated air rearwardly out of the rear heated air outlet in use I communicating 5. dividing wall intake passag further space With this associated wi register incl to be heated circulation o pressure drop heater is in room and not drops in the of the flue Srear register be heated be with a further space to be occupied, e.g. behind a the heating apparatus further including an air e through which air to be heated is drawn from the by the air moving means.

arrangement a rear register may be provided th the heating apparatus. Preferably the rear udes a dual passage register, one passage for air and one for discharge of heated air. The f air through the rear heated space reduces the which would be induced in the room where the stalled if heated air was discharged into the rear replaced with air from the rear room. ressure room with the heater can reduce the effectiveness by countering the buoyancy o-f the flue gases. The may be relatively high and narrow with the air to iny drawn in along a lower passage of the register i e.g. to be drawn into the intake air of the air moving means, heated air being passed out through the hiyher portion of the register. The rear register is high and narrow rather than short and wide, to fit between items of furniture.

The heat exchanger is preferably located immediately above the combustion chamber with the heat exchanger being provided with an intake mouth through which combustion products from both the radiant and the convective burner arrangements pass.

o00 00o Preferably the heat exchanger has both front and back heat exchange surfaces over which air is caused to move by the air T_ i moving means so that the air is heated thereby. The heat exchanger for example may comprise an upright generally flat structure having an internal chamber through which com)bustion products pass from a lower intake mouth to an upper discharge point, the front and hack surfaces of the chamber defining the front and back walls of the heat exchanger over which the air is moved. If desired there may he provided one or more transfer passages through the heat exchanger from the front to t'e back surface thereof so that air may flow through the transfer passage(s). The transfer passage(s) can increase the effective surface area of the heat exchanger. Also in the case where the heat exchanger is made of metal plate, the transfer passage(s) can he used to provide structural rigidity to the heat exchanger. The heat exchanger may include one or more surface depressions which extend inwardly from the front or back surfaces, preferably the front depression(s) meeting the rear S o0 depression(s) internally and being secured thereto. The depressions provide increased surface area, structural rigidity to the heat exchanger and also cause the combustion prorlucts 2C. flowing through the chamber in the heat exchanger to flow around the depressions thereby providing effective heat exchange with a large surface area rather than the combustion products channeling directly towards the discharge point.

Possible and preferred features of the present invention will now be described with particular reference to the accompanying drawings. However it is to be understood that the t S features illustrated in and described with reference to the 0 0 0 0 0 drawings are not to be construed as limiting on the scope of the invention. In the drawings: Fig. 1 shows a front perspective view of a heating apparatus in accordance with a preferred embodiment of the invention, Fig. 2 shows a schematic side sectional view not necessarily along a single section line, but illustrating the operation of the heating apparatus according to the preferrer emhodiment of the present invention, Fig. 3 is a middle vertical sectional view through a heater, Fig. 4 is a right side vertical sectional view, Fig. 5 is a left side vertical sectional view, Fig. 6 is a front sectional view taken along the line VI-VI of Fig. 3, Fig. 7 is a schematic view of the burner controls, Fig. 8 is an illustrative side sectional view of a further possible embodiment, Fig. 9 is an illustrative side sectional view of a yet further possible embodiment.

Referring to Figs. 1 to f, the heating arrangement includes a casing 10 having a front face 11 which comprises a lower air intake louvred section 1? through which air to he heateH is drawn by the fan 13. The location of the fan 13 at the bottom of the casing and in particular below the level of the combustion chamber 20 means that the fan always remains relatively cool. The heater can he operated without the fan 13 operating, as in the event of a power failure or as the user wishes, without effect on the burner operation and without the need for interlocking controls.

SThe combustion chamber 20 includes gas jet 21 which directs gas upwardly into the radiant burner arrangement 22 which has on the front face thereof ceramic tiles 23 provided with passages ~-~mupfur-ira-, uiu i -o through which the gas passes and in use undergoes combustion.

The ceramic burner tiles 23 radiate heat through the transparent ceramic shielding glass 24 and through the front grille 25 into the space to be heated as illustrated by the arrows 26. By control of the gas supplied by the jet 21 to the radiant burner arrangement 22, the amount of radiant heat directed into the space can be user controlled, The combustion chamber 20 also includes a convective burner arrangement 28 which is shown as a gas burner arranged a short distance convective arrangement collected mouth 31 Combustion discharged which conv diverter 3 S combustion any flue exchanger in front of the ceramic burner tiles 23. The burner arrangement 28 and the radiant burner 22 both produce combustion products which are by the heat exchanger 30 which has an open intake arranged immediately above the combustion chamber products pass through the heat exchanger 30 and are through the top thereof to the draft diverter 32 'eys the combustion products to a flue 33. The draft 2 is arranged to change the direction of flow of products before passing them to the flue 33 so that downdraft does not pass directly down into the heat 30. The draft diverter 32 has an open front 34 through which flue downdrafts are directed. Also if the is blocked, combustion products can pass through the op 34 of the draft diverter to enter the space being heated the upper grille As shown in Fig. 3 the heat exchanger 30 includes wall 37 and a back wall 38. The heat exchanger 30 is Ssheet metal for example and the front and back walls 37, depressed sections 39 which meet towards the upper end flue 33 en front through a front made of 38 have and are I secured together e.g. by spot welding to provide structural Ji rigidity to the heat exchanger, to increase the effective surface area and cause combustion products flowing upwardly i; through the heat exchanger to flow around the depressions 39 5. before passing to the draft diverter 32.

In the lower portion of the heat exchanger 30 the depressions meet and are perforated to define a passage 40 to enable air to flow through the heat exchanger from the front to the back or vice versa.

The fan 13 forces air upwardly through passage la which is arranged on the back wall of the heater casing. At the upper end of the passage 14 the air flow underyoes a change of direction so as to then pass downwardly over both the front and back walls 37, 38 of the heat exchanger 30 so as to be heated thereby. The air passing up generally the centre line of the passage 14 as shown in Fig. 3 is turned by curved deflector o plates 42 (see also Fig. 6) to pass downwardly along rear passage 43 over the back face 3P of the heat exchanger 30. Air passing generally up the left hand and right hand sides of the passage 14 is directed hy curved deflector plates 4A (see Figs.

4 and 5) so as to pass downwardly along front passage 45 over the front wall 37 of the heat exchanger 30. The two streams of S air directed down over the front 37 of the heat exchanger also 25. induce some extra air flow in through the top louvre 35 over the heat exchanger front face. The top louvre 35 discharges all of the heated air when the fan 13 is not operating. The air i passing along front passage 45 is deflected by curved plate 46 a to pass out of the front of the heater at the top of the grille 25 as shown by arrow 47. Some air passing down rear passage 43 passes through the transfer passage 40 in the heat exchanger to also be deflected by the curved plate 46 to pass out of 'the front of the heater. As seen in Fig. 4 air passing down the right hand side of the rear passage 43 passes to the side of the combustion chamber 20 and is directed out the front of the heater by curved plate 49 (see also Fig. Air passing down the left hand side of the rear passage 43 also passes by the side of the combhusti on chambier 20 and emerges From, the -rrnnt of the heater.

As shown in Fi gs. 5 and! 5 the heatinfl apparatus can include a rear register section 50 which as seen in Fig. 6 is elongated in the vertical direction. The inlet passage Fl of the rear register section 50 is arranged in the lower part so that air is dr a wn i n war dlIy from a room on the rear side of a wall where the heater is installed, the rear the s econd( r o om. Air drawn 0 0 51 passes downwardly to the p: pas s in g down the left hand sic of passing down to the curvec the heater, passes through tl which extends from the rear outlet opening into the second Y As previously explained, arrangement in which air is exchanger is the most efficregister section 50 opening into ni through the rear register inlet fan 13. Some of the heated air e of the rear passage 43, instead I plate 48 and out of the front of ie rear register outlet passage passage 43 to the rear register the counter flow heat exchange forced d owvnw ar dlIy o v er a h ea t ient for extracting heat since the cool est air encounters the heat exchanyer surfaces nearest to the flue outlet, the heated air passing out from the heater into the space to be heated immediately after passing over the hottest surfaces of the heat exchanger nearest to the combustion chamber

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Referring to Fig. 7 which shows schematically the burner controls for a gas fired burner arrangement, inlet gas on line passes gas pressure regulator P1 and then passes to flame failure safety valv e 82. To ignite the pilot light 83, the push button control 84 is depressed to open valve 82. L'hen the pilot 83 has been properly ignited, the thermocouple R5 controls operation of the solenoid 8P which will maintain the valve "9 open to gas flow as long as the pilot 83 is properly ignited.

Gas to the radiant burners 22 is supplier' through line 7 to a rotating control valve 88 by means of which a user can either direct gas to none of the three burners (as shown), to the centre one of the radiant burners 22 by rotating the valve RP Sslightly anti-clockwise, or to all three burners 2? in a further position of the valve 88. In this way the user can control the radiant heat output of the apparatus by selecting none, one or three of the burners 22. This means that the user can select an appropriate number of b u r n e r s to produce a feeling of comfort appropriate to the particular air temperature.

Gas to the convective burner 28 is supplied through line 9n which includes a modulating valve 91 which is illustrated I schematically as having an associated thermostat control knoh n7 and a temperature sensing element 93 which includes a Stemperature responsive fluid. Expansion and contraction of the fluid in the element 93 causes the bellows q4 in the modulating valve 91 to control the gas flow through line on to the convective burner 28. In this way a user can adjust the thermostat control knob 92 to select a desired room air 0 0 1 o O temperature to be achieved if desired solely by convective heating. That is, the radiant burners 22 can be all turned off 13 -Iwli, and the convective burner 28 ignited and the fan 13 operated to blow heated air from the apparatus into the room until the desired temperature is reached. At any time, whether or not the convective burner 28 is operating, the user can operate the valve 88 to select one or three radiant burners to supplement or substitute for convective heating.

Fig. 8 shows an alternative possible arrangement in which air is drawn from the room generally around and from immediately above the combustion chamber 20 so that the air passes upwardly over the front and back surfaces of the heat exchanger, the heated air thence heing drawn downwardly through the passage 11' to be forced by the fan 113 out through the front bottom of the heater. This arrangement uses a parallel flow heat exchanger, i.e. in which the air being heated flows generally in the same direction as the combustion products. In this arrangement if a rear register 150 is provided an additional air moving fan 160 would need to be provided to cause a forced air flow out through the register 150.

In Fig. 9 there is a further alternative arranyement using a counterflow heat exchange for good heat exchange efficiency. In this arrangement air to be heated is drawn in through the top front of the heater, passes downwardly over the front and back faces of the heat exchanger and is then drawn rearwardly either through the passage 240 through heat exchanger or to the left 2 and right sides of the combustion chamber 220 as shown by arrows 248 to then pass through the fan 213 out of the lower front of S the heater. As with Fig. 8, a rear register 250 would require an additional air moving fan 260 to force a flow of heated air out through the rear register 250.

It will be seen that the preferred embodiments of the heating apparatus according to the present invention described and illustrated herein will enable separate independent control of the radiant and convective heat output so that the user can optimise the balance of air room heating by convective means with a radiant heat level for occupant comfort. The provision of separate controllable burners, one for convective heatiny and one for radiant heating (and assisting convective air heating) enables the independent control. The use of counterflow heat exchange enables good heating efficiencies to he achieved. The placement of the fan at the lower portion of the heater below the burner level eliminates the need for over-temperature protection systems which are needed to protect a Fan if it is located above the burner and which become operational if for example there is a power failure leaAing to fan stop)paje and overheating of the fan as combustion below the level of the fan S continues.

It will be appreciated that variations in the details of the invention as herein described and illustrated can be made. Two such possible variations are the substitution of a balanced flue S arrangement or a powered flue arrangement instead of the draft diverter. In a balanced flue arrangement the combustion air inlet and flue outlet are located externally and in immediate proximity to each other, the inlet conveying comhustion air to the combustion chamber. The provision of a balanced flue i 0 I minimrnises interference to combi)ustion since fluctuations in 00 oo a external air movement have balanced effects in the combustion air intake and in the combustion products outlet. In a powered flue arrangement, an enclosed fan forces the combustion products into a flue pipe through which they are conveyed to the outside of the buildiny.

It is to be understood that various alterations, 1 5. modifications and/or additions may be made to the features of the possible and preferred em bodiment(s) of the invention as herein described without departing from the spirit and scope of the inv nrition.

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Claims (15)

1. A heating apparatus for heating a space to be occupied, the heating apparatus including a combustion chamber where combustion of a fuel occurs, a radiant heat source associated with the combustion chamber and operative to be heated by the combustion of the fuel and to provide a radiant heat output to heat the space where the heating apparatus is installed, a heat exchanger arranged and operative to collect combustion products from the combustion chamber and to convey those combustion products to a discharge point, air moving means arranged and operative to move air over heating surfaces of the heat exchanger so that the air is heated 0 thereby, the heated air being expelled in use into the space to 0000o thereby provide a convective heat output to heat the space, and 0 selectively operable heat control means for enabling a user to control the radiant heat output at least partially independently of the convective heat output or vice versa. S

2. A heating apparatus as claimed in claim 1 wherein the selectively operable heat control means includes a radiant heat controller for enabling a user to control the radiant heat output at least partially independently of the extraction of heat from the heat exchanger by the air moving over the heating surfaces whereby the user can select a desired radiant heat output level while maintaining a generally independent air heating effect within the space caused by heated air being expelled by the air moving means into the space.

3. A heating apparatus as claimed in claim 1 or 2 wherein the selectively operable heat control means includes a convective heat controller for enabling a user to control the convective heat output at least partially independently of the radiant heat output, the convective heat controller enabling user control of the £9 ''9 41 I l~ operation of the air moving means and/or control of the temperature of the heating surfaces of the heat exchanger over which the air is moved by the air moving means.

4. A heating apparatus as claimed in claim 3 wherein the convective heat controller includes a thermostat which the user can set to the desired temperature of air within the space, the air moviny means and/or the heat oxchanger surface temperature being responsive to the thermostat. 1

5, A heating apparatus as claimed in claim 4 wherei n the combustion chamber includes a convective burner arrangement and an independent radiant burner arrangement, the radiant burner arrangement being operatively associated with the radiant heat source, the convective burner arrangement being operative to burn fuel, the heat exchanger being arranged and operative to col lect comhustion products fron the convective burner arrangement and to pass those products to the discharge point o with little of the heat of combustion generater at the 0 .*0 convective burner arrangement being radiated to the space to be occupied.

A heati ny apparatus as cl aimed in claim E wherein the combustion products from both the radiant and convective burner arranyements are collected by the heat exchanger so as to enable relatively efficient heat extraction from the combustion A products.

7. A heating apparatus as claimed in any one of the preceding 8 0 claims wherein the air moving means is operative to move air ao i I over the heating surfaces of the heat exchanger in a generally downwards direction so that the coldest air first reaches the heating surfaces immediately before the discharge point, the air II- heing passed downwardly towards the hotter surfaces of the heat exchanger nearer to the combustion chamber.

8. A heating apparatus as claimed in claim 7 wherein the air moving means is located at a lower portion of the heating apparatus and below the combustion chamher.

9. A heating apparatus as claimed in claim 2 wherein the air movi n means is arranged to draw air into the heating apparatus at an upper portion of the apparatus and to draw the air downwardly over the heat exchanger throuuh the air moving means and thence out of a front of the heating apparatus and into the space.

A heating apparatus as claimed in claim R wherein the air moving means is operative to draw air from the front bottom of the heating apparatus and to move the air upwardly through an upright passage which opens at an upper portion of the heatiny 0 0 apparatus, the air emerging from t'he upper end of the passage then heing directed downwardly over the heat exchanger.

11. A heati n a p a r a t us as claimed in any one or the p)recedi n claims and further includiny a rear heated air outlet operative to pass heated air rearwardly out of the heating apparatus, the rear heated air outlet in use communicating with a further space to be occupied, the heating apparatus further including an air intake passage throigh which air to be heated is drawn from the further space by the air moving means.

12. A heating apparatus as claimed in any one of the preceding S claims wherein the heat exchanger has front and hack heating surfaces over which air is caused to move by the air moving means.

13, A heatiny apparatus as claimed in claim 1? wherein the heat 1n exchanger comprises an upright generally flat structure having an internal chamber through which combustion products pass from a lower intake mouth to an upper discharye point, the front and back surfaces of the internal chanher defining the front and back walls of the heat exchanger over which the air is moved, the heat exchaner further including at least one transfer passage through the heat exchanger from the fronl- to the hack surface thereof so that air can flow t hrouyh the transfer passage(s).

14. A heatiny apparatus as claimed in claim 1I whorein the heat exchanger includes one or more surface depressions which extend inwardly from the front or back surfaces so that the front and back walls meet internally at the location of the surface depressions, the depressions thereby interrupti ng the direct flow of combustion products from the combustion chamber to the discharye point. V

15. A heating ajpparatus substantially as herein h! Fore descri erl ith particular reference to the accompanying drawinys. Dated this Ath day of fctoher, 1 "P2 PATENT ATTnRNEY SERVICES Attorneys for RHEEM AUSTRALIA LIMITED