IE85940B1 - A boiler - Google Patents

Abstract

ABSTRACT An enclosed oil/gas fired boiler has heat transferring baffle assemblies 15 stacked one on top of the other within a combustion enclosure 1. Hot combustion gases are led back and forth across the enclosure in each assembly 15 by deflector plates 26 and 17 from a cut out portion 27 to another cut out portion 27 in the next uppermost baffle‘

Description

A boiler Introduction The present invention relates to a boiler and in particular to an enclosed boiler, such as fired by oil or gas.

There are many constructions of such boilers and the present invention is specifically directed to improvements in the invention of European Patent No. EP 0 616 676B, the disclosure of which is included herein in it’s entirety by way of reference.

This is a very efficient construction of enclosed boiler. However, there have been various developments since this invention was devised. For example, there is increasing efforts being made to improve the thermal efficiencies of such boilers. For example, very many of these boilers are now fitted with some form of condensing unit, being often referred to as condensing boilers, whereby additional heat is extracted from the flue gases. Further, the more one can increase the thermal efficiency of the boiler itself and thus reduce the temperature of the flue gases as they exit the boiler, the better. This, with the advent of condensing boilers, is particularly the case as the less the work required from the condensing unit, the better. Thus, the cooler the exhaust gases are on entering the condensing unit or condensing portion of the boiler, the better. There is thus a need for a more efficient boiler.

The present invention is directed towards providing an improved boiler based on the principles of the boiler described in the aforementioned European Patent No. 06166768.

Statements of invention According to the invention, there is provided an enclosed boiler comprising: a substantially rectangular cuboid heat exchange combustion enclosure formed by a base wall, two pairs of substantially parallel upstanding side walls on the base and a top wall, at least portion of which walls are hollow for containing system water; heat transferring baffle plate assemblies stacked one on top of the other within the enclosure; each baffle plate assembly comprising a rectangular base plate configured to fit substantially across all the enclosure and having front, rear and side edges, the baffle plate assembly further comprising at least three substantially parallel, along most of their length, upstanding deflector baffle plates on the base plate, and a cut-out portion adjacent one corner of the base plate forming one of an inlet and outlet, the deflector plates and base plate of each baffle plate assembly and the underside of the base plate of the baffle assembly stacked on it forming, with the side walls of the enclosure, a tortuous passageway for leading combustion gases from a gas inlet formed by the cut-out portion of the lower base plate to a gas exit formed by the cut-out portion of the upper base plate, the gases passing back and forth across the enclosure between the inlet and outlet such that the gases first pass between one of a pair of side walls and a deflector baffle plate and then back and forth between the at least two sets of deflector baffle plates and finally between a deflector baffle plate and the other of the pair of side walls.

The advantage of this boiler is that it gives increased thermal efficiency and because there are effectively a greater number of passageways through which the gases progress, the overall heat transfer is not alone more efficient, but is also less likely to cause distortion of the baffle plate assemblies. This is particularly important with more recent constructions of burners which operate at higher pressures than heretofore.

In one embodiment of the invention, there are three spaced-apart deflector baffle plates, namely, a pair of outer baffle plates and an intermediate plate, the outer baffle plates extending from one edge adjacent the cut-out portion of the base plate to a position spaced-apart from the opposed edge and the intermediate baffle plate extending from the opposed edge to a position spaced-apart from the other edge.

The advantage of the additional baffle plates is that they provide a better support for each other and there is less warping of the baffle plate assemblies in use.

Ideally, the cross sectional area of the passageway between each baffle plate and the cross-sectional area between another baffle plate and a side wall of the enclosure is substantially constant. By ensuring that the cross sectional area of the passageway is essentially constant throughout its length, there does not tend to be speeding up or slowing down of the gases and thus the gases progress through the boiler with the least possible pressure loss and this leads to a more efficient heat transfer.

Ideally, the spacing between a baffle plate and the respective edge of the base plate forms an opening of substantially the same cross-sectional area as the rest of the passageway. This again improves the progression of the combustion gases through the boiler.

In another embodiment of the invention, each baffle plate assembly comprises: a pair of outer deflector baffle plates, each extending from a position at one edge of the base plate towards an adjacent orthogonal edge and then parallel to said orthogonal edge to a position spaced-apart from the opposed parallel edge; and an intermediate deflector plate extending between the outer deflector baffle plates from a position at the opposed edge and parallel to the orthogonal edges to a position spaced-apart from the other edge.

The advantage of this type of assembly is that it provides even more support for each of the heat transfer baffle plate assemblies and further, there is less warping.

In another embodiment of the invention, the cross-sectional area of the passageway between parallel portions of the deflector baffle plates and side walls is substantially constant.

In some embodiments of the invention, the cut-out portion of each baffle plate assembly is of substantially the same cross-sectional area as that of the passageway. This provides a smoother flow of gas between the assemblies.

Ideally, the cut-out portion is rectangular.

Detailed Description of the invention The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective partially cut-away view of a boiler according to the invention, ’ Fig. 2 is a perspective view of a baffle plate assembly used in the boiler, Fig. 3 is an exploded view of a number of baffle plate assemblies, and Fig. 4 is a perspective view, similar to Fig. 2, of another baffle plate assembly.

Referring to the drawings, and initially to Fig. 1 thereof, there is illustrated an enclosed boiler, indicated generally bythe reference numeral 1. The boiler 1 is generally of rectangular shape is transverse cross section and comprises a base 2, a top 3 and side walls formed by a rear tank 4, a front tank 5 and a pair of main side tanks 6 and 7. The base 2, upstanding side walls 4, 5, 6 and 7 and top wall 3 define a substantially rectangular heat exchange combustion enclosure, indicated generally by the reference numeral 10. Water is circulated through the side walls 4, 5, 6 and 7 in conventional manner. There is also illustrated an oil burner 11 and an exhaust gas flue 12 in the top wall 3. The boiler, except for the construction of the heat transferring baffle plate assemblies, is of conventional construction and requires no further description. Mounted within the enclosure are three heat transferring baffle plate assemblies, indicated generally by the reference numeral 15, together with a top baffle plate assembly, indicated generally by the reference numeral 16. It will be noted that the heat transferring baffle plate assemblies 15 are stacked one on top of the other within the enclosure and the final top baffle plate assembly 16 is then on top of these. The lowermost baffle plate assembly 16 is mounted on inwardly directed lugs or support plates on the side walls 4, 5, 6 and 7.

Referring now to Fig. 2, each baffle plate assembly 15 comprises a rectangular base plate 17 configured to fit relatively snugly, that is to say, substantially across all the enclosure and having a front edge 18, rear edge 19 and side edges 20. A cut-out portion, indicated generally by the reference numeral 25. forms one of an inlet and an outlet. Mounted on the base plate 17 are three spaced-apart deflector baffles, namely a pair of outer baffle plates 26 and an intermediate baffle plate 27. it will be noted that the outer baffle plates 26 extend from the edge 18 which is adjacent the cut-out portion 25 to a position spaced-apart from the opposed rear edge 19 and are parallel, while the intermediate baffle plate 27 extends from the rear edge 19 to a position spaced-apart from the front edge 18. All three baffle plates 26, 27 are parallel to the side edges 20. The top baffle plate assembly 16 comprises a base plate 28 and an upstanding baffle arrangement 29 (see Fig. 3). in operation, as can be seen from Figs. 2 and 3, the combustion gases rise through one cut-out portion 25 forming an inlet and then along against the side wall 7 of the boiler around the baffle plate 26 forward in the boiler, then around the baffle plate 27, then back between the next baffle plate 26 and the rear wall 4 of the boiler, as shown in Fig. 2, and then upwards through the next cut-out portion 25 which forms the outlet for the lower baffle assembly 15 and then in turn becomes the inlet to the next baffle assembly 15 and so on to the top baffle plate assembly 16.

Each baffle plate assembly, in use, forms by the deflector plates and base plates of each baffle plate assembly and the underside of the base plate of the baffle assembly stacked on it together, with the side walls of the enclosure, a tortuous passageway for leading combustion gases from a gas inlet formed by the cut-out portion of the lower base plate to a gas exit formed by the cut-out portion of the upper base plate, the gases passing back and forth across the enclosure between the inlet and outlet at least four times around each baffle plate assembly.

Preferably, the cross sectional area of the cut-out portion 25 equals the cross- sectional area of the passageway formed by either one of the side walls 6 and 7 and the baffle plates 26 or between the baffle plate 27 and the other plates 26. This tortuous passageway is basically of the same cross sectional area throughout its length, the spacing between the baffle plates 26 and 27 and the spacing between the baffle plates 26 and 27 with the respective side walls 6 and 7 of the boiler being so chosen to provide this.

Referring to Fig. 4, there is illustrated an alternative construction of heat transferring baffle plate assembly, indicated generally by the reference numeral 30, comprising again, a base plate 31 having a front edge 32, a rear edge 33 and orthogonal adjacent side edges 34. Mounted on the base plate 31 is a pair of outer deflector plates 35, each extending from a position 36 at the front edge 32 towards an adjacent orthogonal side edge 34 and then parallel to the said orthogonal edge 34 to a position spaced-apart from the opposed parallel edge, in this case, the rear edge 33. An intermediate deflector plate 36 is mounted between the two outer plates 35 extending from the position at the opposed edge 33 and parallel to the orthogonal edges 34 to a position spaced-apart from the other edge 32, as can readily easily be seen from Fig. 4. Again, in operation, these deflector plates 35 and 36 work in substantially the same manner as heretofore.

Needless to say, while in the embodiments described above, the gases pass back and forth across the enclosure between the inlet and outlet four times, the number of passes may be increased by simply providing additional baffle plates. For example, in the baffle plate assembly illustrated in Fig. 2, an additional baffle plate, similar in construction to the intermediate baffle plate assembly 27, could be mounted outside one of the baffle ptates 26 to provide an additional passageway. In this embodiment, the cut-out portion would be adjacent the rear edge, rather than the front edge, of the base plate 17. It will readily be appreciated how this can be done.

In the specification the terms “comprise, comprises, comprised and comprising" or any variation thereof and the terms “include, includes, included and including” or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

The invention is not limited to the embodiment hereinbefore described, but may be varied in both construction and detail within the scope of the claims.

Claims (2)

1. An enclosed boiler comprising: a substantially rectangular cuboid heat exchange combustion enclosure formed by a base wall, two pairs of substantially parallel upstanding side walls on the base and a top wall, at least portion of which walls are hollow for containing system water; heat transferring baffle plate assemblies stacked one on top of the other within the enclosure; each baffle plate assembly comprising a rectangular base plate configured to fit substantially across all the enclosure and having front, rear and side edges, the baffle plate assembly further comprising at least three substantially parallel, along most of their length, upstanding deflector baffle plates on the base plate, and a cut-out portion adjacent one corner of the base plate forming one of an inlet and outlet, the deflector plates and base plate of each baffle plate assembly and the underside of the base plate of the baffle assembly stacked on it forming, with the side walls of the enclosure, a tortuous passageway for leading combustion gases from a gas inlet formed by the cut-out portion of the lower base plate to a gas exit fon'ned by the cut-out portion of the upper base plate, the gases passing back and forth across the enclosure between the inlet and outlet such that the gases first pass between one of a pair of side walls and a deflector baffle plate and then back and forth between the at least two sets of deflector baffle plates and finally between a deflector baffle plate and the other of the pair of side walls.

2. A boiler as claimed in claim 1. in which there are three spaced-apart deflector baffle plates, namely, a pair of outer baffle plates and an intermediate plate, the outer baffle plates extending from one edge adjacent the cut-out portion of the base plate to a position spaced-apart from the opposed edge and the intermediate baffle plate extending from the opposed edge to a position spaced-apart from the other edge. A boiler as claimed in ciaim 2, in which the cross-sectional area of the passageway between each baffle plate and the cross-sectional area between another baffle plate and a side wall of the enclosure is substantially constant. A boiler as claimed in claim 2 or 3, in which the spacing between a baffle plate and the respective edge of the base plate forms an opening of substantially the same cross-sectional area as the rest of the passageway. A boiler as claimed in claim 1, in which each baffle plate assembly comprises: a pair of outer deflector baffle plates, each extending from a position at one edge of the base plate towards an adjacent orthogonal edge and then parallel to said orthogonal edge to a position spaced-apart from the opposed parallel edge; and an intermediate deflector plate extending between the outer deflector baffle plates from a position at the opposed edge and parallel to the orthogonal edges to a position spaced-apart from the other edge. A boiler as claimed in claim 5, in which the cross-sectional area of the passageway between parallel portions of the deflector baffle plates and side walls is substantially constant. A boiler as claimed in any preceding claim, in which the cut-out portion of each baffle plate assembly is of substantially the same cross-sectional area as that of the passageway. A boiler as claimed in any preceding claim, in which the cut-out portion is rectangular. A boiler substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.