GB2185095A

GB2185095A - Heat exchange apparatus

Info

Publication number: GB2185095A
Application number: GB08630972A
Authority: GB
Inventors: Martin Anthony Neligan
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-01-07
Filing date: 1986-12-29
Publication date: 1987-07-08
Anticipated expiration: 2006-12-29
Also published as: EP0230789A2; GB2185095B; IE860031L; GB8630972D0; EP0230789A3

Abstract

Heat exchange apparatus 2 such as a boiler or air heater comprises a chamber 6 in a housing 4 through which hot gases flow and a heat exchange wall 8 which has a plurality of corrugations 10 defining ridges 12 and troughs 14 over which the hot gases flow in order to increase the surface area in the chamber 6 for heat exchange purposes. A baffle 18, which may be movable towards and away from the wall 8, directs the hot gas flow over the wall. The baffle maybe removable to facilitate cleaning of the heat exchanger. The ridges and troughs may alternatively be provided by a flattened tube bent into a zig-zag shape. In Figure 8, hot gases flow along two walls of the apparatus. The fire basket 26 is arranged to slide between two rooms. <IMAGE>

Description

GB 2 185 095 A 1

SPECIFICATION

Heat exchange apparatus This invention relatesto heat exchange apparatus.

Varioustypes of heatexchange apparatus are known. Thus, for example, oneform of known heat exchange apparatuswhich includes a combustion chamberis known as a wrap-around backboiler. Re- 10 cently designed wrap-around back boilers are sometimes referred to as easy-to-clean back boilers.

It is an aim of the present invention to provide heat exchange apparatus which gives an efficient heat transfer and which is also able easilyto be cleaned.

Accordingly, this invention provides heat exchange apparatus comprising a housing, a chamber in the housing through which hot gasesflow in use of the heatexchange apparatus, and a heatexchange wall which is positioned in the chamber and which 20 has a plurality of corrugations defining ridges and troughs overwhich the hot gasesflow in orderto increase the surface area in the chamberfor heatexchange purposes.

The heat exchangewall with its corrugations en- 25 ablesthe eff icient heattransferof heat as it passes through the heat exchange apparatus. This is because the ridges and troughs present an increased surface area over a straight wall and this increased surface area is available for heat exchange purposes.

30 The heat exchange wall with its corrugations is also such that it is able to be relatively easily cleaned.

The corrugations in the heat exchange wall may be V-shaped, U-shaped or rectangular in cross section. Other shaped corrugations may also be employed.

The heat exchange wall is preferably formed as a rearwall of the housing. Such a construction facilitates easy cleaning of the heat exchange apparatus.

The heat exchange wall may be made from a 40 single sheet of metal. The single sheet of metal may be bent orformed to produce the required corrugations. The corrugations are advantageous from the ease of cleaning aspect in that substantially all of the wall is able to be seen so that cleaning can be 45 carried out more easily and more efficentlythan with othertypes of configuration. Furthermore, where the heat exchange wall forms the rearwall of the housing and it is desired to weld the heat exchange wall to side walls of the heat exchange apparatus, then welded seams may be employed that are substantially entirely visible from both the front and the back of the heat exchange apparatus. This means thatthe joints to form the welded seams can be welded on both sides which greatly reduces any possibility of 55 gas leakage from within the heat exchange appar atus.

Preferably, the heat exchange apparatus includes baff le means forfitting into the corrugations of the heat exchange wall to restricttheflow of the hot gas through the chamber.

The provision of the baffle means may greatly improvethe heat exchange efficiency of the heat exchange apparatus. The baffle means acts as an inducerto induce the greater heateff iciency.

65 The baffle means may be a fixed baffle means.

However, preferably,the baffle means is a movable baffle meanswhich can be moved from a closed position in which substantially all the hot gases are restricted from flowing overthe heat exchange wall,to 70 an open position in which substantially all the hot bases are caused to flow overthe heat exchange wall.

Generally,the movable baffle means can be moved by sliding it backwards and forwards and it 76 can be slid to any desired position between itsfully closed position and its fully open position. When the baffle means is in a partially open position, it is able to restrictthe amount of combusted hot gases that can flow upwardlythrough the heat exchange appar80 atus and, in so doing, it restricts the amount of the gases in contact with the heat exchange wall. The heat is thus extracted onlyfrom the hot gasesthat are in direct contact with the heat exchange wall.

With the baff le means in the closed position, all the 85 hot gases are restricted from flowing upwards through the heat exchange apparatus and thus from making contactwith any boilerthat may be present in the heat exchange apparatus. In this case, the baffle means would only be used in the closed posi- 90 tion when hot water was not required but when rad iant heatwas required.

With the baffle means in the open position, the maximum amount of hot gases are allowed to f low through the heat exchange apparatus and more 95 specifically between the baff le means and the heat exchange wall. The baff le means in the open position will reduce the temperature of combustion since, as the baffle means is adjusted inwardly, the passage defined between the heat exchange wall and the 100 baffle means will become more and more restricted, thereby allowing a smaller amount of hot gas to flow therethrough. This will cause the hot gases to flow faster and this will in turn cause more vigorous combustion with a resultant increase in temperature.

105 This makes combustion more efficient, as atthe higher temperature, more of the gases are burnt. This in turn reduces polution.

Preferably, the baffle means comprises a plurality of plate devices that slide between the ridges and 110 into the troug hs of the corrugations of the heat exchange wal 1. As indicated above, the more the baffle means moves towards a closed position, the more it restricts the flow of hot gases that can pass through the passage defined by the heat exchange wal I on 115 the one hand and the baffle means on the other hand.

Where the baffle means is a fixed baffle means, it may be arranged such that it can be removed during cleaning but, between cleaning periods, itwill be fixed in a desired position ableto givethe bestdes- 120 ired results.

The baffle means may be made in one piece orit may be made up of several parts in orderto facilitate removal and subsequent cleaning.

The heat exchange apparatus may have one or 125 more hatches or doors for allowing removal of the baffle means for cleaning purposes.

The baffle means may be carried between side walls by lugs, brackets or channels fixed in position, for example bywelding or other means.

130 The baffle means, esppciallyfor example in the 2 GB 2 185 095 A case of oil or gas fired heat exchange apparatus, can be twin walled to hold water. Water inlets and outlets maybe provided to extend beyond the thickness of the side walls and the main heat exchange appar5 atus.

The side wal Is may have a cutout to accommodtite the extended water inlets and outlets, and connection to the water inlets and outlets maybe by means of a flexible hose. This may be advantageous in help- 10 ing to reducethe size of the heat exchange appar atus.

The heat exchange apparatus may include a combustion chamber.

The combustion chamber may be provided in close physical contact with the heat exchange wall. Alternatively, the combustion chamber can be placed at a remote location with respectto the heat exchange wall. Thus the combustion chamber may be placed in a different room to that in which the heat 20 exchange wall is located. For example,the heat exchangewall can be placed in an adjacent room behind a room that contains the combustion unit. If desired,the heat exchange wall can be placed in a room above a room containing the combustion chamber, 25 or it may even be placed in a roof space. All that is required to connectthe combustion chamberto the heat exchange wall is an appropriate flue. This offers a considerable advantage to users of traditional fireplaces in which radiant heat is the only heattransfer 30 and in which the traditional fireplaces are required to remain without losing any of their efficiency. For such as arrangement, a simple unitcan be inserted into theflue in order to tranpferthe combustion gasesto the heat exchangewall.

The heat exchange apparatus of the present inven- 100 tion may include a fan.

The fan maybe used to improve operating efficiency of the heat exchange apparatus.

The baffle means maybe formed as a unitwhich is 40 substantially identical to the heat exchange wall. Thus, for example, the baffle means can be fabricated in double hollow skinned steel so that, when it is pushed forward towards it closed position, its projecdons and recesses fit into complementary re- 45 cesses and projections on the heat exchange wall. With such an arrangement, water connections may be provided by means of flexible hoses.

The heat exchange apparatus may also include plate means which is positioned outside the baffle 50 means and which is for increasing radiant heat.

The plate means may be placed at a distance away from a plate of the baffle means in orderto allow combustion gases to flow upwards on the outside of the plate of the baffle means, whereupon at the top, the hot gases are drawn downwards to flow between the plate of the baffle means and the said plate means which is positioned outside the baffle means.

Embodiments of the invention will now be described solely bylivay of example and with referenceto the accompanying drawings in which:

Figure 1 is aside sectional view of first heat exchange apparatus; Figure 2 is aside sectional view of second heat exchange, apparatus and which is like the heat ex- 05 change apparatus shown in Figure 1; Figure3 is a perspective sectional view of heatexchange apparatus similarto that shown in Figures 1 and 2; Figure4is a side sectional view of heatexchange apparatus in theform of an oil fired central heating boiler; FigureSis a section through heat exchange apparatus in theform of a flue pipe heat exchange unit; Figure 6is a perspective view of further heatex- change apparatus; Figure 7is a side sectional view of heatexchange apparatus in theform of a back boiler,the back boiler including baffle means and an additional plate located outside a face plate of the baff le means; 80 Figures 8and 9 are side sectional viewsthrough double-faced back boilers; 1 Figure 10 is a sectional viewthrough heat exchange apparatus and illustrates how hot gases can be diverted; Figure 11 is a perspective view of a heat exchange wal 1 formed from one piece of pipe; Figure 12 is a cross section through heat exchange apparatus and shows the use of the heat exchange wall of Figure 11; Figure 13 is a perspective view of the heat exchange apparatus shown in Figure 12; Figure 14 is a perspective viewfrom another angle of part of the heat exchange apparatus shown in Figures 12 and 13; and Figure 15showsfurther heat exphange apparatus employing a pair of doors and a pair of baffle means.

Referring to Figure 1, there is shown heatexchange apparatus 2 comprising a housing 4, a chamber 6 in the housing 4through which hot gases flow in use of the heat exchange aparatus 2, and a heat exchange wall 8. As can be seen, the heat exchange wall 8 is positioned in the chamber 6 and it has a plurality of corrugations 10 defining ridges 12 and troughs 14. Hot gases flow overthe ridges 12 105 and the troughs 14 in orderto increase the surface area in the chamber 6for heat exchange purposes. The corrugations 10 are generally V- shaped in cross section.

It will be seen from Figure 1 that the heat exchange 110 wall 8 is formed as a rearwall of the housing 4. In fact the heat exchange wall 8 lies adjacent a rearwall 16 of the housing 4 so that the heat exchange wall 8 forms a secondary or inner rearwall of the housing 4.

The heat exchange wall 8 is madefrom a single 115 sheet of metal which is bent to produce the cor rugations 10.

The heat exchange apparatus 2 shown in Figure 1 includes baffle means 18forfitting as shown into the corrugations 10 of the heat exchange wall 8 to re- 120 strictthe flow of the hotgasesthrough the chamber 4. The baffle means 18 acts as an inducer and is effective for improving heat exchange efficiency and general operation of the heat exchange apparatus 2.

The baffle means 18 is a movable baffle means 125 which can be moved from a closed position in which substantially all the hot gases are restricted from flowing overthe heat exchange wall 8, to an open position in which substantially all the hot gases are caused to flow overthe heat exchange wall 8. Figure 130 1 shows the baffle meansin a nearly closed position.

i GB 2 185 095 A 3 The baffle means 18 is made as a one piece unit which comprises a back plate 20 from which a series of plates 22 project. The plates 22 extend into the troughs 14 as shown. The plates 22 thus define a pas- 5 sage 24 between themselves and the heat exchange wall 8 through which the hot gases in the chamber6 can be constrained to pass.

The heat exchange apparatus 2 may include a fan (not shown) for increasing movement of hot gases.

Referring now to Figure 2, sim ilar pa rts as i n Figure 1 have been given the same reference numerals and their precise construction and operation will not again be given. Figure 2 shows mainlythe baffle means 18 being removed forenabling a cleaning op- 15 eration to be effected. The precise shape of the corrugations 10 enables virtually the entire surface of the heat exchange wall 8 to be seen and easilyto be cleaned. Figure 2 also shows the chamber 6 provided with a bottom wa I 126.

In the following Figures 3 to 15, similar parts as in Figure 1 have been given the same reference numerals and their precise construction and operation will not again be given.

In Figure 3, it will be seen that the corrugations 10 25 are rectangular in cross section. This means thatthe troughs 14 are also rectangular in cross section.

In Figure 4, there is shown heat exchange apparatus 2 in the form of an oil fired central heating boiler. The heart of the boiler is provided by the heat ex- 30 change apparatus shown in Figure 3. In addition, in Figure 4, it will be seen thatthe boiler is provided with a front door 28 and a flue pipe 30. Aflame 32 is provided in the chamber 6 so thatthe chamber 6 in Figure 4 may be regarded as a combustion chamber.

The gas required for the flame 32 is provided via feed apparatus 34which may include appropriate valves and fans. The housing 4 is mounted on legs 36.

In Figure 5, there is shown heat exchange apparatus 2 in the form of a flue pipe heat exchange unit.

40 The flue pipe heat exchange unit has an inletflue pipe 38 and an outletflue pipe 40.

Referring now to Figure 6, there is shown heat exchange apparatus somewhat similarto Figure 1 except thatthe baffle r-neans 18 has a vertical back plate 45 20 so thatthe plates 22 are all of the same size. The housing 4 has a front door 28 and the chamber 6 is fed with hot gases from a vertical pipe 42. The gases pass up the pipe 42 through an inlet pipe 44, through the passage 24 and outthrough an outlet pipe 46.

Figure 7 shows heat exchange apparatus 2 in the form of a back boiler. Plate means in the form of a vent plate 48 is provided outside the baffle means 18 as shown and spaced apart from the back plate 20. 'Thus ihe bent plate 48 and the back plate 20 combine to define a passage 50. The passage 50 extends into a passage 52 which is defined between the bent plate 48 and the lower-most plate 22. The passage 52 then extends into the passage 24 defined between the plates 22 and the corrugations 10. The chamber 6 can 60 be provided with a coal, wood or gas operated fire 54. Hot gases from the fire 54 pass in the direction of the iflustrated arrows and outthrough an outlet 56 in tine. top of the housing 4 as shown. The fire 54 rests cn Ene bottom wall 26 which forms a grate.

65 Fgures 8 and 9 show heat exchange apparatus 2 in 130 the form of double faced back boilers. As can be seen, two baffle means 18 are employed. The hot gases pass outthrough an outletflue pipe 58. It is sometimes desirable to have one fireplace or 70 chamber arrangement as shown in Figures 8 and 9. The bottom wall 26forms a fire basket as shown which can be arranged to slide or otherwise move on a hearth 60 from one room to another. As the fire basket is slid backwards and forwards, itwill locate 75 in appropriate closed positions in a channel or similar device. As the combustion gases rise to the top of the heat exchange wall 8 as shown, they are drawn back down through the heat exchange apparatus, as shown bythe arrows, and returned up the other side, 80 also as shown bythe arrows. Thus, the heat exchange apparatus shown in Figures 8 and 9 is effective to shed heat on both sides of the heat exchange wall 8. This is a particularly eff icient construction.

Referring nowto Figures 10, 11, 12 and 13, there is 85 shown heat exchange apparatus 2 from various angles. The heat exchange wall that is used is shown in Figure 11 and it may be formed from a pipe of the correct diameterthat is pressed almostflat as shown orthat is pressed out of shape to almost closed or 90 meeting. The pipe is then bentto the illustrated shape. The arrangement is of advantage as it can be built into, or between, brickwork.

Figures 10, 12 and 13 illustrate by means of the arrows, howthe combustion gases are drawn from 95 the fire 54 and through the apparatus, the combustion gases then passing underneath the fire 54 itself to be reburnt as they pass through the combustion zone. For clarity, in Figures 10 and 13, the baff le means 18 has been removed. The heat exchange 100 apparatus2shown in Figures 10, 1 1f 12 and 13 may be most efficient in a closed unit such for example as a stove or a room heater.

Figure 14 shows the heat exchange wall 8 of Figure 11 based in a housing 4 having a door 62. The baffle 105 means 18 is illustrated positioned between the cor rugations 10 of the heat exchange wall 8.

Figure 15 shows an arrangement somewhat similarto Figure 14 but with two doors 62,64. As can be seen from the arrows, which illustrate the direction 110 of flow of the hot gases, the heat exchange wall 8 is effective on both sides so that there is a doubling up of heat. Two baffle means 18 are also employed as shown. As shown bythe arrows,the hot gases are induced through one side of the unit and down the 115 otherside. The reverse arrangement can howeverbe employed.

Itwill be seen from the drawingsthat all thevarious designs of the heat exchange apparatus 2 are such thattheyare able relatively easilyto be cleaned.

120 The heat exchangewalls 8 are in particular relatively easilycleaned and their entire surface area thatfaces outwardly is substantially visible rendering itthat much easierto clean. The use of the heatexchange walls 8 also provide good efficiency in thetransfer of 125 heat.

It isto be appreciated thatthe embodiments of the invention described above with reference to the accompanying drawings have been given by way of example only and that modifications may be effected. The heat exchange apparatus may include com- 4 GB 2 185 095 A 4 ponents and parts that are usual and of standard design for known types of heat exchange apparatus. Such known components and parts will not effectthe operation of the heat exchange apparatus according 5 to the present invention.

If desired, the exchange apparatus may be used for hotair systems. The heat exchange apparatus may also be used for heat recovery, where steam and fat for example, would be passing through the heat ex- 10 change apparatus from a kitchen or similar environment where air is extracted and is laden with smoke, steam, fat and the 1 ike.

Claims

1. Heat exchange apparatus comprising a housing, a chamber in the housing through which hot gases flow in use of the heat exchange apparatus, and a heat exchange wall which is positioned in the 20 chamber and which has a plurality of corrugations defining ridges and troughs overwhich the hot gases flow in order to increase the surface area in the chamber for heat exchange purposes.

2. Heat exchange apparatus according to claim 1 25 in which the corrugations in the heat exchange wall are V-shaped, U- shaped or rectangular in cross section.

3. Heat exchange apparatus according to claim 1 or claim 2 in which the heat exchange wall is formed 30 as a rearwall of the housing.

4. Heat exchange apparatus according to anyone of the preceding claims in which the heat exchange wall is made from a single sheet of metal.

5. Heat exchange apparatus according to anyone 35 of the preceding claims and including baffle means forfitting into the corrugations of the heat exchange wall to restriathe flow of the hot gases through the chamber.

6. Heat exchange apparatus according to claim 5 40 in which the baffle means is a fixed baffle means.

7. Heat exchange apparatus according to claim 5 in which the baffle means is a movable baffle means which can be moved from a closed position in which substantially all the hot gases are restricted from flowing overthe heat exchange wall, to an open position in which substantially all the hot gases are caused to flow overthe heat exchangewall.

8. Heat exchange apparatus according to anyone of the preceding claims in which the baffle means is 50 made in one piece.

9. Heat exchange apparatus according to anyone i of the preceding claims and including a combustion ch a m b e r.

10. Heat exchange apparatus according to any one ofthe preceding claims and including a fan.

11. Heat exchange apparatus according to any one of the preceding claims and including plate means which is positioned outside the baffle means and which is for increasing radiant heat.

1,21 Fleat exchange apparatus substantially as hereir. described with reference to the accompanying drawings.

for tier Majesty's Stationery Office by Croydon Printing Company (UK) Ltd, 6187, D8991685. Pi, by The Patent Office, 25 Southampton Buildings, London, VU'C2A W1,from vAlfch copies maybe obtained.