GB2346433A

GB2346433A - A boiler assembly

Info

Publication number: GB2346433A
Application number: GB0001741A
Authority: GB
Inventors: Raymond Rennison
Original assignee: Worcester Heat Systems Ltd
Current assignee: Bosch Thermotechnology Ltd
Priority date: 1999-02-02
Filing date: 2000-01-27
Publication date: 2000-08-09
Anticipated expiration: 2020-01-27
Also published as: GB2346433B; IE20000070A1; GB9902276D0; GB0001741D0

Abstract

A boiler assembly comprises a boiler 14 and an insulation cover 15 each having first and second ends and one or more sides, the first end of the boiler having an opening 30 suitable for receiving hot gases from a burner 24, and the second end and the one or more sides of the boiler having inner and outer spaced apart walls 16 and 17, 19 and 20, defining therebetween a space 18, 22 in which a liquid to be heated can flow. The insulation cover has a first insulated end wall 23 and one or more insulated side walls 21 which surround the side wall or walls of the boiler, preferably in spaced relationship thereto. One or more vents 28 may be provided in the boiler side wall or walls at or adjacent to the second end of the boiler so that in use hot gases from the burner pass along the inner wall(s) of the boiler and then through the vent(s) before passing along the outside of the outer wall(s) of the boiler between the boiler and the cover 15 and exiting through flue means 29 preferably at the first end of the boiler. Pipes for circulating liquid in the boiler are preferably connected to the second end of the boiler. The first insulated end wall of the insulation cover or the entire cover may be releasably connected to the boiler. The boiler may include an annular baffle box (31, Figure 4) which may be slidably removable. Air venting channels (32, Figure 5) may be provided.

Description

A BOILER ASSEMBLY This invention relates to a boiler assembly of the type which is typically used for heating water or other liquids.

A typical water heater which may be mounted on an external wall of a building, has a box-like heat exchange chamber into which hot gas is introduced, provided from an oil or gas fired burner,'with the heat exchange chamber itself having hollow walls and through which water to be heated can flow, the walls of the combustion chamber thereby acting as a jacket for containing the water. Exhaust gases from the burner are then conventionally directed out of the chamber, such as by the use of baffles, through a generally small opening which may conveniently be the same opening through which the nozzle end of the burner protrudes for providing the hot combusted gases. The exhaust gas is then directed out of the building by means of a flue so that even though the water jacket is disposed on the inside of the building the water inside is heated by gases which never enter the building other than within the heat exchange chamber and are vented immediately therefrom to the outside atmosphere.

One problem with this conventional design of water heater is that the externally visible parts of the water jacket protrude into the inside of the building into which it is fitted so that, necessarily, only'one side of the water jacket in these regions is ever heated by the combustion'gases even though the wall of the combustion chamber adjacent the burner may typically be heated on both sides due to the exhaust flue being directed on the outer face of the combustion chamber.

Accordingly, for a given rate of heat exchanged there is a lower limit on the size of the water jacket and, even then, access to the inside of the combustion chamber is usually very limited because of the small size of the aperture needed for introducing hot gases into the chamber and exhausting them therefrom.

Also, although this conventional kind of water heater can be made very compact and is typically serviced from the outside of the building, nevertheless a problem with this general construction is that access to the inside of the heat exchange chamber is often very difficult because of the requirement to maximise the surface area of the inside of the chamber to thereby maximise the efficiency of heat exchange. This is usually achieved by venting the combusted gases out of the same aperture through which the combustion head projects or through a separate small aperture after a series of baffle plates, thus making it difficult to inspect and service, where necessary, the inside of the chamber.

According to a first aspect of the invention there is provided a boiler assembly comprising a boiler and an insulation cover each having first and second ends and one or more sides, the first end of the boiler having an opening for receiving hot gases from a burner and the second end and the side or sides of the boiler having inner and outer spaced apart walls defining therebetween a space in which a liquid to be heated can flow, the insulation cover having a first insulated end wall and one or more insulated side walls which surround the side wall or walls of the boiler in spaced relationship thereto, and one or more vents in the boiler side wall or walls at or adjacent to the second end of, the boiler so that in use hot gases from the burner pass along the inner wall(s) of the boiler and then through the vent(s) before passing along the outer wall(s) of the boiler and exiting through flue means at the first end of the boiler.

Because the combustion gases frorh the heat exchange chamber are passed via the or each vent over the outer walls of the boiler in heat exchange relationship therewith, the heat exchange per unit volume of boiler to the water or other liquid contained within the boiler is improved over, conventional boiler designs.

Preferred and/or optional features pf the first aspect of the invention are set forth in claims 2 to 7.

According to a second aspect of te invention there is provided a boiler assembly comprising a boiler and an insulation cover each having first and second ends and one or more sides, the first end of the boiler having an opening for receiving hot gases from a burner and the second end and the side or sides of the boiler having inner and outer spaced apart valls defining therebetween a space in which liquid to be heated can flow, the insulation cover having a first insulated end wall and one or more insulated side walls which surround the side wall or walls of the boiler, wherein pipes for circulating liquid ; through the boiler are connected to the second end of the boiler and at least the first insulated end wall of the cover is releasably connected to the boiler so as to be'removable to provide ease of access to the boiler.

It will be apparent that with a boiler assembly according to the second aspect of the invention there is the advantage of ease of access to the interior of the boiler because of the large opening afforded by removal of the first end of the insulated cover or the entire cover.

Preferred and/or optional features of the second aspect of the invention are set forth in claims 9 and 10.

According to a third aspect of the invention there is provided a boiler assembly comprising a boiler and an insulation cover each having first and second ends and one or more sides, the side or sides of the boiler having inner and outer spaced apart walls defining therebetween a space in which liquid to be heated can flow, the first end of the boiler having an opening for receiving hot gases from a burner, the insulation cover having a first insulated end wall and one or more insulated side walls which surround the side wall or walls of the boiler in spaced relationship thereto, one or more vents in the boiler side wall or walls at or adjacent to the second end of the boiler so that in use hot gases from the burner pass along the inner wall (s) of the boiler and then through the vent (s) before passing along the outer wall (s) of the boiler and exiting through flue means at the first end of the boiler and a removable annular baffle at the second end of the boiler for redirecting combustion gases back towards the burner prior to exiting via said one or more vents.

Preferred and/or optional features of the third aspect of the invention are set forth in claims 12 to 15.

The invention will now be described, by way of example, with reference ! to the accompanying drawings in which: Figure 1 is a sectional side view of one embodiment of a boiler assembly according to the first and second aspects of the invention installed within an opening of an outside wall of a building, Figure 2 is a sectional perspective'view of the boiler assembly of Figure 1 from the inside of the building, Figure 3 is a sectional perspective view of the boiler assembly of Figure 1 from the outside of the building, Figure 4 is a sectional side view órresponding to that of Figure 3 but showing another embodiment of a boiler assejmbly according to all three aspects of the invention, and I Figure 5 is a sectional perspective view of yet another embodiment of a boiler assembly according to all aspects of thq invention.

Referring firstly to Figures 1 to 3 of the drawings, the boiler assembly 10 shown therein is fixed within an aperture in ah outer wall 11 of a building, the wall 11 having an outer face 12 and an inner face i3.

The boiler assembly comprises a boiler 14 and an insulation cover 15 each of generally cuboidal shape and each having a first end adjacent to the outside of the building, a second end within the building and four sides connecting the first and second ends.

The sides of the boiler 14 have inner and outer spaced apart walls 16 and 17, respectively, defining therebetween a space 18. The second end of the boiler 14 also has inner and outer spaced apart walls 19 and 20 also defining therebetween a space 22 which communicates with the space 18 between the inner and outer walls 16 and 17. The spaces 18 and 22 form a jacket in which water or other liquid to be heated can flow.

The insulation cover 15 has four side walls 21 and a front wall 23 at its first end. The front wall 23 is attached by bolts (not shown) to the front wall of the boiler 14 so as to be in sealing engagement with the inner walls 16 of the boiler 14.

The side walls 21 are clamped between the front wall 23 of the cover 15 and the wall 36 of the boiler 14 and are in sealing engagement with the walls 23 and 36.

A conventional burner 24, which is typically gas or oil fired, is supported by the insulation cover 15 and includes a combustion head 25 which extends in sealing engagement through an aperture in the front wall 23 of the cover 15 and projects into a heat exchange chamber 26 defined by the inner walls 16 and 19 of the boiler 14.

A gap 27, preferably of between 3 mm and 8 mm, is provided between the outer walls 17 of the boiler 14 and the side walls 21 of the cover. Vents 28 are provided in the side walls of the boiler 14 at the second end of the boiler, i. e. the end of the boiler remote from the burner 24, for communicating the inside of the boiler 14 with the gap 27. A flue 29 also communicates with the front end of the gap 27 and extends through the front wall 23 of the nover 15 to the exterior of the building.

Water inlet and outlet pipes (not shown) are connected directly to the second end of the boiler 14. The inlet pipe'directs water to the lower end of the space 22 between the inner and outer end wlls 19 and 20 of the boiler 14 and the outlet pipe communicates with the upper end of the space 22 between the inner and outer end walls 19 and 20. I In use hot gases from the burner 24 enter the front end of the heat exchange chamber 26 and pass along the inner walls 16 of the boiler 14. These hot gases then pass through the vents 28 before passing along the outer walls 17 of the boiler 14 and exiting through the flue 29. Thus, it will be appreciated that even after the hot gases have passed through the vents 28 they continue to exchange heat to the outer walls 17 of the boiler thereby increasing the heat exchange per unit volume of boiler when compared to conventional boilers in which heat exchange only occurs through the inner walls of the boiler. The hot gases also lieat water in the space 22 between the walls 19 and 20 of the boiler 14.

Also, the boiler has a relatively large opening 30 at its front end so that when the burner 24, flue 28 and front wall 23 of the cover 15 have been removed, ease of access is provided to the boiler 14 for servicing and maintenance.

Referring now to Figure 4 of the drawings, the boiler assembly shown therein differs from the boiler assembly of Figures 1 to 3 in that it includes an annular baffle in the form of a baffle box 31 of square cross-section. The baffle box is located within the boiler 14 against the rear end of the boiler remote from the combustion head 25. The baffle box 31 may be open at both ends or only that end adjacent to the burner 24. The baffle box 31 is smaller and shorter than the interior of the boiler 14 thereby allowing hot gases entering the baffle box 31 to flow backwards in the manner shown arrowed so as to further increase the surface area over which intimate scrubbing of the hot gases occur before exiting via the flue 29.

This increases the efficiency of heat exchange between the boiler 14 and water or other liquid. Also, the baffle box 31 prevents the flame/gases from directly exiting through the vents 28 allowing greater radiative heat transfer in the combustion chamber. In addition, the presence of the baffle box 31 has been found to decrease the noise level generated by the combustion of gases from the combustion head 25 by directing the sound waves back towards the combustion head 25, thereby cancelling out some of the propagated sound. The baffle box 31 is preferably slidably removable through the opening 30 of the boiler 14 and is typically mounted on feet (not shown).

Referring now to Figure 5 of the drawings, the boiler assembly shown therein differs from the boiler assembly of Figure 4 in that the insulation cover 15 is formed as a single unit removable in its entitety. It is still attached to the boiler by bolts (not shown) which project from the front face of the boiler and through holes in the cover 15. It also differs from the boiler assembly shown in Figure 4 in that two hollow channels 32 are attached to the rpar face of the boiler 14. One of these channels 32 communicates with the space 22 between the inner and outer walls 19 and 20 of the boiler 14 at the lower end 6 that space 22 and the other of these channels 32 communicates with the space 2 between the inner and outer walls 19 and 20 close to the top end of the boiler 14. Pipes can be connected directly to couplings 34 provided at the upper ends of these channels 32. Seals 35 are provided between the outer wall 20 of the boiler and the side walls of the cover 15 and seals (not shown) are provided between the end wat 23 of the cover 15 and the inner walls 16 of the boiler 14. The provision of the charnels 32, which extend above the spaces 18 and 22, ensures that air within the boiler 114 is vented automatically.

The embodiments described above provide boiler assemblies which make efficient use of the available boiler surface ara, are relatively quiet and in which the interiors of the boilers can be easily accessed.

The embodiments described above are given by way of example only and varous modifications will be apparent to persons skilled in the art without departing from the scope of the invention as defined in the appended claims. For example, the boiler and insulation cover could by cylindrical rather than cuboidal.

Claims

CLAIMS 1. A boiler assembly comprising a boiler and an insulation cover each having first and second ends and one or more sides, the first end of the boiler having an opening for receiving hot gases from a burner and the second end and the side or sides of the boiler having inner and outer spaced apart walls defining therebetween a space in which a liquid to be heated can flow, the insulation cover having a first insulated end wall and one or more insulated side walls which surround the side wall or walls of the boiler in spaced relationship thereto, and one or more vents in the boiler side wall or walls at or adjacent to the second end of the boiler so that in use hot gases from the burner pass along the inner wall (s) of the boiler and then through the vent (s) before passing along the outer wall (s) of the boiler and exiting through flue means at the first end of the boiler.
2. A boiler assembly as claimed in claim 1, wherein pipes for circulating liquid through the boiler are connected to the second end of the boiler.
3. A boiler assembly as claimed in claim 1 or claim 2, wherein at least the first insulated end wall of the cover is releasably connected to the boiler so as to be removable to provide ease of access to the boiler.
4. A boiler assembly as claimed in claim 3, wherein the entire cover is releasably connected to the boiler so as to be removable to provide ease of access to the boiler.
5. A boiler assembly as claimed in any one of claims 1 to 4, wherein the boiler and insulation cover are generally cuboidal in shape.
6. A boiler assembly as claimed in ai) one of the preceding claims, wherein a gap of between 3 mm and 8 mm is provided between the outer wall (s) of the boiler and the side wall (s) of the cover.
7. A boiler assembly as claimed in ahy one of the preceding claims, wherein an annular baffle is provided within the, boiler at the second end thereof for redirecting combustion gases back towards tille burner prior to exiting the boiler via said one or more vents.
8. A boiler assembly comprising a boiler and an insulation cover each having first and second ends and one or more side$, the first end of the boiler having an opening for receiving hot gases from a buriner and the second end and the side or sides of the boiler having inner and outer spaced apart walls defining therebetween a space in which liquid to be heated can flow, the insulation cover having a first insulated end wall and one or more insulated side walls which surround the side wall or walls of the boiler, wherein pipes for circulating liquid through the boiler are connected to the second end of the boiler and at least the first insulated end wall of the cover is releasably connected to the boiler so as to be removable to provide ease of access to the boiler. i
9. A boiler assembly as claimed in claim 1, wherein the entire cover is releasably connected to the boiler so as to be removable to provide ease of access to the boiler.
10. A boiler assembly as claimed in claim 8 or claim 9, wherein the boiler and insulation cover are generally cuboidal in shape.
11. A boiler assembly comprising a boiler and an insulation cover each having first and second ends and one or more sides, the side or sides of the boiler having inner and outer spaced apart walls defining therebetween a space in which liquid to be heated can flow, the first end of the boiler having an opening for receiving hot gases from a burner, the insulation cover having a first insulated end wall and one or more insulated side walls which surround the side wall or walls of the boiler in spaced relationship thereto, one or more vents in the boiler side wall or walls at or adjacent to the second end of the boiler so that in use hot gases from the burner pass along the inner wall (s) of the boiler and then through the vent (s) before passing along the outer wall (s) of the boiler and exiting through flue means at the first end of the boiler and a removable annular baffle within the boiler at the second end thereof for redirecting combustion gases back towards the burner prior to exiting via said one or more vents.
12. A boiler assembly as claimed in claim 11, wherein the annular baffle is slidably removable from within the boiler.
13. A boiler assembly as claimed in claim 11 or claim 12, wherein the boiler and insulation cover are generally cuboidal.
14. A boiler assembly as claimed in claim 13, wherein the annular baffle is in the form of a box open at its end adjacent t the burner or at both ends.
15. A boiler assembly as claimed in claim 14, wherein the box has feet for supporting the box in spaced relationship to the lowermost side wall of the boiler.
16. A boiler assembly substantially as ereinbefore described with reference to Figures 1 to 3, or Figure 4, or Figure 5 of the accompanying drawings.