EP0616676B1

EP0616676B1 - A boiler

Info

Publication number: EP0616676B1
Application number: EP92918953A
Authority: EP
Inventors: Stephen William John Grant
Original assignee: Alley Enterprises Ltd
Current assignee: Alley Enterprises Ltd
Priority date: 1991-12-20
Filing date: 1992-09-11
Publication date: 1997-01-29
Anticipated expiration: 2012-09-11
Also published as: AU2508992A; EP0616676A1; GB2277578B; IE914471A1; GB9411930D0; WO1993013366A1; GB2277578A

Abstract

A gas or oil fired enclosed boiler (1) comprises a base (2), a top (3), a main rear tank (4), a main front tank (5) and a pair of main side tanks (6, 7) which define an enclosure through which flame and hot gases are led from a burner (12) to an exhaust flue (16). The top (3) includes a removable cover for cleaning access. Four baffle assemblies are provided in the boiler. Adjacent transverse baffle plates (30, 31, 32, 33) are longitudinally spaced-apart to define interconnected transverse passageways. Deflectors (50, 51, 52, 54) are welded to each baffle plate (30, 31, 32, 33) and direct flame and hot gases against the water-carrying surface of the boiler. The baffle plate assemblies are removable through the top of the boiler for cleaning.

Description

The invention relates to boilers and especially to an enclosed boiler particularly a boiler which is fired by an oil or a gas burner.
Many different constructions of enclosed boiler are known; see, for example, FR-A-2 129 118. There is, however, a need for an improved construction of such boilers which are as thermally efficient as possible and yet may be easily cleaned.
This invention is directed towards providing such an improved construction of boiler.
According to the invention, there is provided an enclosed boiler comprising the features according to the first portion of claim 1.
Many different constructions of enclosed boiler are known. There is, however, a need for an improved construction of such boilers which are as thermally efficient as possible and yet may be easily cleaned.
This invention is directed towards providing such an improved construction of boiler.
This invention is characterised in that

the sidewall means is substantially rectangular in transverse cross section and comprises a front portion, a rear portion and a pair of side portions extending between the front and rear portions, at least portion of the sidewall means being arranged for carrying water to be heated; in that
the enclosure has an accessway through which access is gained for cleaning; and in that
the heat exchanger means includes:
- at least two generally rectangular transverse baffle plate means extending transversely across the enclosure;
- the transverse baffle plate means being spaced-apart one above the other to define therebetween a transverse flue gas passageway through which hot gases are led,
- each transverse baffle plate means defining an opening,
adjacent transverse bridging means being longitudinally spaced-apart to define therebetween transverse passageway means through which hot gases are led;
each bridging means defining an opening, the opening in one bridging means defining an inlet through which hot gases are introduced into the transverse passageway means and the opening in a following bridging means defining an outlet through which the hot gases are led from the passageway means; and
deflecting means within the transverse passageway for directing hot gases for heat transfer as the gases are led through the passageway means.

In one arrangement the deflecting means is arranged to define with the sidewall means a flue gas passageway of substantially constant cross-section along its length.
In one embodiment of the invention the transverse cross-sectional area of the passageway is greater than or equal to the cross-sectional are of the opening.
Preferably there are at least three transverse baffle plate means defining two interconnected spaced-apart transverse flue gas passageways. Most preferably there are at least four transverse baffle plate means defining three interconnected spaced-apart transverse flue gas passageways.
In one embodiment of the invention, the deflecting means includes baffle plate means.
In another embodiment the deflecting means includes water-carrying tank means.
In a particularly preferred embodiment of the invention the deflecting means and transverse baffle plate means are removable through the accessway for cleaning.
In one arrangement the deflecting means is arranged to turn the gases through at least 180° on passing through each transverse passageway means. The deflecting means may be arranged to turn the gases through at least 360° on passing through each transverse passageway means.
In this case preferably the deflecting means comprises a pair of side portions which are each substantially parallel with and spaced-apart from the sidewall portion of the boiler sidewall means, and a front portion substantially abutting a front portion of the boiler sidewall and following the contour of the inlet and outlet openings to direct gases into and out of the transverse passageway. The deflecting means may include a rear portion substantially parallel with and spaced-apart from the rear portion of the sidewall means.
In one embodiment of the invention the deflecting means includes or is defined by a deflecting water-carrying tank means extending into the enclosure. Preferably the deflecting tank means extends from the front of the boiler and is spaced-apart from the rear of the boiler to define therewith part of the passageway.In another embodiment of the invention the additional deflecting means are provided which is spaced-apart from the sidewall means and the deflecting means to define further legs of a transverse passageway through which the hot gases are led.
Preferably the hot gases are split between two separate inlets to separate passageways from which the gases are discharged to a common boiler outlet. In one case an additional longitudinal bridging means extends between the sidewall means to divide the enclosure into two sub-enclosures. Typically each passageway is provided with bridging means and deflecting means for defining two transverse passageways through which the hot gases are led. Preferably the additional longitudinal bridging means is provided by an additional tank bridging the sidewall means.
In one embodiment of the invention an auxiliary water-carrying means extending between the sidewall means adjacent to the hot gas inlet.
In one arrangement, the accessway is provided in the top of the boiler.
In one embodiment of the invention, the base of the boiler is at least partially defined by a water-carrying bottom tank.
In one arrangement the top of the boiler has an opening defining the flue gas outlet. Alternatively the boiler is a down-fired boiler, the inlet the inlet being provided adjacent the top of the boiler and the outlet being provided adjacent the base of the boiler.
In one embodiment of the invention hot gases are delivered to the inlet from a burner. The boiler may be a gas or oil burner.
The invention will be more clearly understood from the following description 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 arrangement of the boiler;
Figs. 3 to 5 are plan views in the directions of the arrows III, IV and V, respectively in Fig. 1;
Fig. 6 is an exploded view of the baffle arrangement of Fig. 2;
Fig. 7 is an exploded view of the baffle arrangement of another boiler according to the invention;
Figs. 8 and 9 are respectively perspective and plan views of another boiler according to the invention;
Fig. 10 is a plan view of part of a boiler similar to the boiler of Figs. 8 and 9; and
Fig. 11 is a perspective, partially cut-away, view of a further boiler according to the invention.

Referring to the drawings and initially to Figs. 1 to 6, there is illustrated an enclosed boiler according to the invention indicated generally by reference numeral 1. The enclosed boiler 1 is, in this case, of generally rectangular shape in transverse cross-section and comprises a base 2, a top 3 and a water-carrying sidewall tank means comprising a main rear tank 4, a main front tank 5 and a pair of main side tank 6, 7 which define an enclosure through which flame and hot gases are led from an inlet which in this case is supplied by an oil burner 12, to an outlet 15 in the top 3 of the boiler to an exhaust gas flue 16. Water is circulated through the water-carrying tanks 4, 5, 6, 7 for water circulation through the boiler form a water inlet to a water outlet (not shown) which are typically connected into a hot water central heating system. In this case, the top of the boiler 3 is defined by an upper flue plate 25 having an outlet 15 therein for connection to the outlet flue 16 and a removable cover 26 over an accessway 27 through which access is gained for maintenance and cleaning of the boiler, as will be described in more detail below.
The boiler 1 is provided with at least two, and in this case, four transverse bridging means extending transversely across the enclosure. Each of the bridging means are, in this case, defined by transversely extending spaced-apart baffle plates 30, 31, 32, 33, the lowermost 30 of which is supported on mounting lugs 35 on the front, rear and sidewalls of the boiler. Adjacent transverse baffle plates 30, 31, 32, 33 are longitudinally spaced-apart to define therebetween transverse passageways 40 through which the hot gases from the burner are led. The baffle plate 30 is cut-away at the front thereof to define together with the adjacent front and side tanks of the boiler and inlet opening 50 through which gases are led into the first transverse passageway 40 defined between the baffle plate 30 and the following baffle plate 31. Similarly, the baffle plate 31 is cut-away to define an outlet opening 45 through which the gases are led from the transverse passageway 40 into the following transverse passageway defined between the plates 30 and 32. Similarly, the baffle plate 32 is cut-away to define an opening 46 for leading the gases from the second transverse passageway into the third transverse passageway defined between the transverse plates 32, 33 and the baffle plate 33 is also cut-away at 47 to define an opening into the final transverse passageway before discharge into the exhaust gas flue 16. The area of the openings is preferably less than or equal to the transverse cross sectional area of the passageway.
Deflecting means for directing hot gases passing through the transverse passageways 40 against the water-carrying tanks of the boiler is, in this case provided by first, second, third and fourth deflector plate means 50, 51, 52, 54 welded to the respective transverse baffle plates 30, 31, 32, 33 respectively. The deflecting means in this case turn the gases through substantially 180° as they travel through a passageway. Each of the first, second and third deflector plate means 51, 52, 53 are of similar shape and comprise a rear portion 60 which is substantially parallel with and spaced-apart from the rear tank of the boiler, a pair of side portions 62, 63 which are substantially parallel with and spaced-apart from the side tanks of the boiler and a front portion 64 which is of generally apex shape and extends to substantially abut the front tank 5 of the boiler 1 and follows the contour of the inlet and outlet openings 50, 45, 46 to direct hot gases into an outlet of the respective transverse passageways.
The fourth and uppermost deflecting plate means 54 is of generally channel shape, as illustrated, to direct the gases rising from the opening 47 defined by the transverse baffle plate 33 into the flue gas outlet of the boiler.
The second baffle plate 31 and associated deflector means 51 is mounted in use on the lower deflecting means 50. Similarly the third baffle plate 32 and associated deflector means 52 is mounted on the second deflector plate means 51. The uppermost baffle plate 33 and associated deflector plate means 53 is in turn mounted on the third deflector plate means 52. In this way the baffle plates and associated deflector plates can be easily removed through the top access opening for cleaning by first removing the uppermost baffle plate 33 followed by the remaining baffle plate and associated deflector means. For ease of handling, the baffle plates may be provided with handles.
In use, and referring particularly to Figs. 1 and 6 with the baffle plates and deflector means in position and the accessway closed, the burner 12 is activated and hot gases and flames from the burner are projected from the burner 12 towards the rear tank 4 of the boiler where they are turned and lick the surfaces of the side tanks 6, 7 and front tank 5 of the boiler before passing through the opening 50 into the first transverse passageway 40. In the transverse passageway 40 they are initially directed rearwardly, then sidewardly along the rear tank 4 and forwardly before passing through the opening 45 into the following transverse passageway. This process is continued as illustrated in Figs. 1 and 6.
Because of the configuration of the baffle plates and deflector plates, a very high heat transfer efficiency is obtained because the hot gases must travel a long distance over the surfaces of the water-carrying tanks of the boiler, giving up a large proportion of their heat before discharge to the exhaust gas flue. Before cleaning, the access cover is removed and the baffle plates and deflector plates are readily removed as described above.
Referring to Fig. 7 there is illustrated another arrangement of baffles/deflector means for use with the boiler described with reference to Figs. 1 to 6. The arrangement is similar to the arrangement illustrated in Fig. 6 except that in this case the rear portion is omitted. This provides for ease of construction and free flow of gases through the passageway.
It will be appreciated that each of the deflector plate means may be of any desired shape and arrangement. For example, a substantially triangular or six or more sided shaped arrangement may be provided. It will also be appreciated that the deflector plate means may be provided, at least in part, by water-carrying tank means.
Referring to Figs. 8 and 9 there is illustrated another boiler 100 according to the invention which is similar to the boiler described with reference to Figs. 1 to 6, and like parts are assigned the same reference numerals. In this case a deflecting tank means 101 extends into the enclosure from the front tank 5 towards but spaced-apart from the rear tank 4 and the gases are deflected as illustrated particularly in Fig. 8 for enhanced heat transfer. Typically the baffle plate 30 is supported on the tank 101 and the additional baffle plates 31, 32, 33 are supported on the lowermost baffle plate 30.
Referring to Fig. 10 there is illustrated another boiler 110 which is similar to the boiler 100 and like parts are assigned the same reference numerals. In this case additional deflector plate means 111, 112, 113 are provided spaced-apart from the tank 101 and the rear tank 4 and side tanks 6, 7 to define a transverse passageway through which the gases are led as illustrated. In this case the gases are turned substantially through 360° as they pass through each transverse passageway for improved heat transfer.
Referring to Fig. 11 there is illustrated another boiler 120 according to the invention which is similar to the boiler of Figs. 1 to 6 and like parts are assigned the same reference numerals. In this case an additional tank 121 extends between the front tank 5 and rear tank 4 dividing the enclosure into two adjacent sub-enclosures 122, 123, each of which is provided with baffle plates 124, 125 and associated deflector plates 126, 127 which are arranged to turn the gases through substantially 180° as they travel through each transverse passageway of the sub-enclosure 122, 123. The flame and hot gases from the burner are divided between two inlets 128, 129, for each sub-enclosure 126, 127 and the gases are combined at the outlets from the sub-enclosures 126, 127 for discharge through a common flue gas outlet.
It will also be appreciated that while for ease of cleaning, the bridging means and deflector means are, in most cases, of plate material, at least some of them may be defined by water-carrying tanks for enhanced heat transfer.
It will further be appreciated that an accessway may be provided at any suitable location. For example, the front and/or one or both sides of the boiler may be provided with the accessway.
It will also be appreciated that the boiler may be a down-firing boiler.
The boiler may include an auxiliary tank adjacent the burner. This may, for example, be in the form of a tube of gun barrel material for carrying water to further enhance the heat transfer efficiency. The lowermost baffle may also be supported on the auxiliary tank.

Claims

An enclosed boiler (1,100,110,120) of the type comprising:
a base (2);

a top (3);

sidewall means (4,5,6,7) extending between the base (2) and top (3) and defining therewith an enclosure through which hot gases are led from an inlet (12) to a flue gas outlet (15); and

heat exchanger means (30,31,32,33,51,52,53, 54,101,111,112,113,121,124,125) within the enclosure for directing hot gases for heat transfer as the gases are led through the enclosure;
characterised in that
the sidewall means (4,5,6,7) is substantially rectangular in transverse cross section and comprises a front portion (5), a rear portion (4) and a pair of side portions (6,7) extending between the front and rear portions (5,4), at least portion of the sidewall means (4,5,6,7) being arranged for carrying water to be heated; in that

the enclosure has an accessway (27) through which access is gained for cleaning; and in that

the heat exchanger means (30,31,32,33,51,52, 53,54,101,111,112,113,121,124,125) includes:

at least two generally rectangular transverse baffle plate means (30,31,32,33,124,125) extending transversely across the enclosure;

the transverse baffle plate means (30,31,32,33,124,125) being spaced-apart one above the other to define therebetween a transverse flue gas passageway through which hot gases are led,

each transverse baffle plate means (30,31,32,33, 124,125) defining an opening (50,45,46,47),

the openings (50,45,46,47) defined by adjacent transverse baffle plate means (30,31,32,33,124,125) being offset,

the opening (50,45,46,47) in one transverse baffle plate means (30,31,32,33,124,125) defining an inlet (50,45,46) through which hot gases are introduced into the transverse passageway (40) and the opening defined by a following transverse baffle plate means (30,31,32,33,124,125) defining an outlet (45,46,47) through which the hot gases are led from the passageway (40), and

deflecting means (51,52,53,54,101,111,112, 113,121) associated with the transverse baffle plate means (30,31,32,33,124,125) for directing hot gases for heat transfer as the gases are led through the passageway (40).
A boiler as claimed in claim 1 wherein the deflecting means (51,52,53,54,101,111,112,113,121) is arranged to define with the sidewall means (4,5,6,7) a flue gas passageway (40) of substantially constant cross-section along its length.
A boiler as claimed in claim 1 or 2 wherein the transverse cross-sectional area of the passageway (40) is greater than or equal to the cross-sectional area of the opening (50,45,46,47).
A boiler as claimed in any preceding claim, wherein there are at least three transverse baffle plate means (30,31,32,33,124,125) defining two interconnected spaced-apart transverse flue gas passageways (40), preferably there are at least four transverse baffle plate means (30,31,32,33,124,125) defining three interconnected spaced-apart transverse flue gas passageways (40).
A boiler as claimed in any preceding claim wherein the deflecting means (51,52,53,54,101,111,112,113, 121) includes baffle plate means (51,52,53,54,111, 112,113) and/or water-carrying tank means (101,121), preferably the deflecting means (51,52,53,54,101,111, 112,113) and transverse baffle plate means (30,31, 32,33,124,125) are removable through the accessway (27) for cleaning.
A boiler as claimed in any preceding claim wherein the deflecting means (51,52,53,54,101,111,112,113, 121) is arranged to turn the gases through at least 180°, and preferably at least 360° on passing through each transverse passageway means (40), preferably the deflecting means (51,52,53,54,101,111, 112,113,121) comprises a pair of side portions (62,63) which are each substantially parallel with and spaced-apart from the sidewall portion (6,7) of the boiler sidewall means (4,5,6,7), and a front portion (64) substantially abutting a front portion (5) of the boiler sidewall means (4,5,6,7) and following the contour of the inlet and outlet openings (50,45,46) to direct gases into and out of the transverse passageway (40), preferably the deflecting means (51,52,53,54,101,111,112,113) includes a rear portion (60) substantially parallel with and spaced apart from the rear portion (4) of the sidewall means (4,5,6,7), preferably the deflecting means (51,52,53,54,101, 111,112,113,121) includes or is defined by a deflecting water-carrying tank means extending into the enclosure, preferably the deflecting tank means (101,121) extends from the front (5) of the boiler and is spaced-apart from the rear (4) of the boiler to define therewith part of the passageway (40).
A boiler as claimed in any preceding claim wherein additional deflecting means (111,112,113) are provided which is spaced-apart from the sidewall means (4,5,6,7) and the deflecting means (51,52,53,54,101,121) to define further legs of a transverse passageway (40) through which the hot gases are led.
A boiler as claimed in any preceding claim wherein the hot gases are split between two separate inlets (128,129) to separate passageways (40) from which the gases are discharged to a common boiler outlet (16).
A boiler as claimed in claim 7 wherein an additional bridging means (121) extends between the sidewall means to divide the enclosure into two sub-enclosures (122,123), preferably each passageway (40) is provided with bridging means (124,125) and deflecting means (126,127) for defining two transverse passageways through which the hot gases are led preferably the additional bridging means (121) is provided by an additional tank (121) bridging the sidewall means (4,5,6,7).
A boiler as claimed in any preceding claim including an auxiliary water-carrying means extending between the sidewall means (4,5,6,7) adjacent to the hot gas inlet, preferably the auxiliary water-carrying means comprises a water-carrying tube extending between the sidewall means (4,5,6,7).
A boiler as claimed in any preceding claim, wherein the accessway (27) is provided on the top of the boiler, preferably the base (2) of the boiler is at least partially defined by a water-carrying bottom tank (2), preferably the top (3) of the boiler has an opening defining the flue gas outlet (15).
A boiler as claimed in any of claims 1 to 10 wherein the boiler is a down-fired boiler, the inlet being provided adjacent the top (3) of the boiler and the outlet being provided adjacent the base (2) of the boiler.
A boiler as claimed in any preceding claim, wherein hot gases are delivered to the inlet from a burner (12) such as an oil burner (12) or a gas burner.