IE55153B1

IE55153B1 - An enclosed boiler

Info

Publication number: IE55153B1
Application number: IE131084A
Authority: IE
Original assignee: Grant Stephen William
Priority date: 1984-05-25
Filing date: 1984-05-25
Publication date: 1990-06-06
Also published as: GB8513306D0; IE851310L; GB2159610B; BE902513A; GB2159610A

Description

2 2 55153 The present invention relates to an enclosed hot water boiler of the type comprising a water jacket surrounding a combustion chamber accommodating a burner.

The terra "Burner" as used in this specification refers not 5 only to a burner for liquid or gaseous fuel but also to a burner or retort for any suitable solid fuel.

Many elaborate constructions of such boilers are known such as for example boilers having a top opening and having a water jacket forming the side walls of the 10 chamber. Baffles are usually mounted in the chamber to direct combustion gases and flame from the burner, against the water jacket. One of the problems with such boilers is that it is extremely difficult to clean them properly because of the arrangement of the baffles. Unless 15 they are cleaned regularly the combustion chamber can clog up with soot deposits resulting in considerably decreased heat transfer efficiency and in extreme cases to failure of the burner to operate. Further, the baffles have a relatively short useful life and tend to warp, sag and in 20 some cases to burn out.

This invention is directed towards providing an improved construction of hot water boiler which will overcome at least some of these difficulties. 3 3 55153 According to the invention there is provided an enclosed hot water boiler comprising a box-shaped combustion chamber and flue enclosure in which a burner is mounted, the chamber having a top wall, a bottom wall, a rear wall, 5 a front wall and a pair of side walls, at least portion of the rear and side walls of the chamber being defined by main water tanks, and at least two additional tanks projecting into the chamber from, and being interconnected with at least one main tank, a front bridging member 10 extending between the additional tanks and main side tanks, the main tanks, additional tanks and front bridging member together defining a tortuous flue gas passageway which extends from an inlet adjacent the burner to a discharge outlet to an exhaust flue, the passageway being 15 open towards the front of the boiler, the front bridging member extending between the main side tanks to close off the front of the passageway and the bridging member being removable for cleaning access to the passageway, the additional tanks being so arranged that in use, the flue 20 gases travelling along the passageway are constrained to move at least partially across the flue enclosure between the side tanks.

In one embodiment of the invention the passageway includes at least three successive legs through which gases are 25 led. 4 4 55153 In a particularly preferred embodiment of the invention the width of the passageway decreases between the inlet and outlet.

Preferably the passageway includes successively rising and 5 falling legs through which the gases are led. Typically the passageway comprises a first rising leg extending from an inlet adjacent one main side tank, a second rising leg extending to a discharge outlet in the top wall of the chamber and an intermediate falling leg extending between 10 the first and second rising legs. The legs may be defined by side tanks and two additional side tanks the additional side tanks extending substantially parallel to the main side tanks. Usually a first additional side tank is spaced-apart from one main side tank to define the first 15 rising leg and a second additional side tank is spaced-apart from the first additional side tank and the other main side tank to form, together with the other main side tank, the second rising leg and with the first additional side tank, the intermediate falling leg, an upper bridging 20 member bridging a main side tank and the second additional side tank, and a lower bridging member bridging the other main side tank and the first additional side tank. 5 55153 Preferably the bridging members are provided by water tanks. Typically the top bridging tank defines the top wall of the combustion chamber. Usually the bottom bridging tank is inclined downwardly from the lowermost 5 end of the first additional side tank to direct combustion gases and flame from the burner into the first rising leg. Preferably the filler member is of a refractory material.

In one embodiment of the invention the base of the chamber is defined by a bottom water tank. Usually the bottom 10 tank is lined with a refractory material. Typically that portion of the back tank between the bottom tank and the inlet to the combustion gas passageway is lined with a refractory material.

In a preferred embodiment of the invention the removable 15 front plate is provided with a socket in which a burner is mounted.

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: 20 Pig. 1 is an exploded perspective view of a hot water boiler according to the invention, 6 6 55153 Fig. 2 is a front view of the boiler of Fig. 1 with a front plate removed, Fig. 3 is a front view of the boiler of Fig. 1 with the front plate in position, 5 Fig. 4 is a cross-sectional view in the direction of the arrows IV-IV in Fig. 3, and Fig. 5 is a cross sectional view in the direction of the arrows V-V in Fig. 3.

Referring to the drawings there is illustrated an enclosed 10 hot water boiler indicated generally by the reference numeral 1. The boiler 1 comprises a box-shaped combustion chamber having a top wall, a bottom wall, a rear wall, a front wall, and a pair of side walls. The top, bottom rear and side walls of the combustion chamber are in this 15 case defined by interconnected water-carrying tanks namely, a top tank 2, a bottom tank 3, a main rear tank 4 and main side tanks 5,6. The front wall is defined by a removable front plate 7 having six spaced-apart mounting holes 8 which engage with complementary mounting bolts 9 20 extending from the front of the side, bottom and top tanks and is fixed in position by fixing nuts (not shown). The front plate 7 is formed with a socket 10 for receiving a burner such as an oil or gas burner or a retort. 7 7 55153 In this case two additional tanks, namely a first additional side tank 15 and a second additional side tank 16 extend into the chamber from, and interconnected with, the rear tank 4 to define a combustion gas passageway 5 through which gases and flames from the burner are led in the direction of the arrows indicated in Fig. 2 from an inlet 18 adjacent the burner to a discharge outlet 19, which in this case is provided by an opening in the top wall of the chamber, for discharge to an exhaust gas flue 10 (not shown). It will be noted that the additional side tanks 15, 16, are substantially parallel to the main side tanks 5, 6 so that access for cleaning to all the heat exchange surfaces in the flue gas passageway can be readily obtained by simply removing the front plate 7.

In this case the passageway includes three successive legs through which gases are led namely, a first rising leg 20 defined between the main side tank 5 and the first additional side tank 15, a second rising leg 21 defined between the main side tanks 6 and the second additional 20 tank 16 and an intermediate falling leg 22 connecting the first and second rising legs 20, 21. Alternate side tanks 5, 6 15, 16 are bridged by bridging members. In this case the main side tank 6 and the second additional side tank 16 are bridged by a bridging member provided by the top 25 tank 2 and the first additional side tank 15 and the other main side tank-5* are bridged by a bottom bridging member 8 5 515 3 provided by a bottom bridging tank 25 connected to the rear tank 4 and the first additional side tank 15. It will be noted that the bottom bridging tank 25 is inclined upwardly from the main side tank 3» towards the 5 first additional side tank 15 to direct combustion gases and flames from the burner into the inlet 18 of the flue gas passageway. To prevent build-up of moisture and hence avoid the risk of corrosion at the location between the bottom bridging tank 25 and the main side tank £ a gap is 10 left between these tanks which is filled by a filter piece 26 of a refractory material. The filler piece 26 can be readily removed to facilitate cleaning of the boiler.

The spacings, dl, d2, d3, d4 and d5 respectively between the side tank 6 and first additional side tank 15, the top 15 tank 2 and first additional side tank 15, the first additional side tank 15 and second additional side tank 16, the second additional side tank 16 and the bottom bridging tank 25, and the second additional side tank 16 and main side tank S are. in this case as follows: 3 20 dl : d2 : d3 : d4 : d5 : 4" (10.2cm) 21/2 (6.4cm) 31/2 (8.9cm) 2V2 (6.4cm) (7.6cm) 9 9 55153 Thus, the width of the passageway decreases between the inlet 18 and outlet 19. The width of the first rising leg 20 is largest to provide a large volume for heat transfer in the hottest region of the boiler. The reduction in 5 size helps to keep the gases moving in the passageway to facilitate high heat transfer efficiency. The relatively narrow gap at those points where the gases change direction in the passageway ensures that the gases are not slowed down between the legs of the passageway.

To protect the bottom tank 3 and that portion of the rear tank 4 between the bottom tank 3 and the inlet 18 to the flue gas passageway 17 the bottom tank and that portion of the rear tank referred to are lined with a refractory material, in this case with firebrick material 28.

One advantage of the invention is in providing a hot water boiler which may be easily cleaned and which has a high thermal efficiency. In tests thermal efficiency of the boiler has been measured at between 85% and 87%.

It will be appreciated that not all the walls of the 20 chamber need necessarily be defined by water tanks. The top tank may, for example, be provided by a bridging plate however, in the case where the top tank provides a bridge between a main tank and one of the additional tanks for improved heat transfer it is particularly advantageous to 55153 ΊΟ provide the discharge outlet in such a tank. Similarly, it will be appreciated that the bottom tank is not an essential feature of the invention however it is advantageous from a safety point of view for cooling the 5 base of the boiler and hence avoiding the risk of a fire resulting from a hot base of the boiler coming into contact with flammable material, for example an oil spillage on the floor on which the boiler is sited.

It will further be appreciated that the discharge outlet 10 from the boiler to a flue need not necessarily be provided on the top wall of the chamber. It could for example be provided at the top of one of the side or rear walls.

It will further be appreciated that while it is advantageous for ease of maintenance to provide the front 15 plate with a socket in which the burner is mounted this is not an essential feature of the invention as the burner could be mounted in any suitable location, for example it could extend through an opening in one of the side or rear tanks.

It will further be appreciated that it is not essential that all of any particular wall of the chamber be defined by a water tank, portion of the wall only need be defined by a water tank and the other portion provided by suitable plate material. For ease of construction and to achieve 11 11 55153 maximum efficiency it is however advantageous to define the walls of the chamber by water carrying tanks.

It will further be appreciated that while for ease of construction the top tank extends in a substantially horizontal plane it may be inclined upwardly or downwardly with respect to the adjacent main side or rear tank. Similarly, while it is advantageous to arrange the bottom bridging tank to be inclined upwardly for improved heat transfer efficiency and to direct combustion gases and flames from the burner into the inlet of the combustion gas passageway this is not an essential feature. For example the bottom bridging tank could also extend in a horizontal plane. In this case a filler piece may not be necessary and the tank could be connected directly to its adjacent main side tank.

It is also envisaged that while for ease of construction the additional tanks are arranged substantially vertically with the gases being led through successively rising and falling legs the tanks could be arranged in any desired orientation to provide an open-fronted flue gas passageway. For example, the tanks may be arranged substantially horizontally and the gases led from one main side tank towards the other, suitable spacing being provided between the additional tanks and the main tanks and additional bridging members being provided as required 12 12 55153 to interconnect the various legs of the passageway. Various arrangements of tanks which may be used with an enclosed boiler according to this invention are described in my co-pending Irish Patent Application No. 1309\84.

It will further be appreciated that the front plate need not necessarily define all of the front wall of the chamber. For example the bottom portion of the front wall of the chamber may be defined by a water tank. Such a water tank may extend for example to the lowermost point 10 of the bottom bridging tank. In this case the socket for the burner may be provided through the front tank.

Claims

1. 55153

2. 1. An enclosed hot water boiler comprising a boxshaped combustion chamber and flue enclosure in which a burner is mounted, the chamber having a top wall, a bottom wall, a rear wall, a front wall and a pair of side walls, at least portion of the rear and side walls of the chamber being defined by main water tanks, and at least two additional tanks projecting into the chamber from, and being interconnected with at least one main tank, a front bridging member extending between the additional tanks and main side tanks, the main tanks, additional tanks and front bridging member together defining a tortuous flue gas passageway which extends from an inlet adjacent the burner to a discharge outlet to an exhaust flue, the passageway being open towards the front of the boiler, the front bridging member extending between the main side tanks to close off the front of the passageway and the bridging member being removable for cleaning access to the passageway, the additional tanks being so arranged that in use, the flue gases travelling along the passageway are constrained to move at least partially across the flue enclosure between the side tanks.

3. 2. A boiler as claimed in Claim 1 in which the passageway includes at least three successive legs through which gases are led. 14 14 5 515 3

4. 3. A boiler as claimed in claim 1 or 2 in which the width of the passageway decreases between the inlet and outlet. 4. Ά boiler as claimed in any of claims 1 to 3 in 5 which the passageway includes successively rising and falling legs through which the gases are led.

5. A boiler as claimed in claim 4 in which the passageway comprises a first rising leg extending from an inlet adjacent one main side tank, a second rising leg 10 extending to a discharge outlet in the top wall of the chamber and an intermediate falling leg extending between the first and second rising legs.

6. A boiler as claimed in claim 5 in which the legs are defined by the main side tanks and two additional side 15 tanks, the additional side tanks extending substantially parallel to the main side tanks.

7. A boiler as claimed in claim 6 in which a first additional side tank is spaced-apart from one main side tank to define the first rising leg and a second 20 additional side tank is spaced-apart from the first additional side tank and the other main side tank to form, together with the other main side tank, the second rising leg and with the first additional side tank, the 15 15 55153 intermediate falling leg, an upper bridging member bridging a main side tank and second additional side tank, and a lower bridging member bridging the other main side tank and the first additional side tank. 5 8. λ boiler as claimed in Claim 7 in which the bridging members are provided by water tanks.

8. 9. A boiler as claimed in Claim 8 in which the top bridging tanks defines the top wall of the combustion chamber. 10 10. A boiler as claimed in Claim 8 or Claim 9 in which the bottom bridging tank is inclined downwardly from the lowermost end of the first additional side tank to direct combustion gases and flame from the burner into the first rising leg. 15 11. A boiler as claimed in Claim 10 in which the bottom bridging tank is spaced-apart from its adjacent main side tank, the gap between the tanks being filled by a removable filler member.

9. 12. A boiler as claimed in Claim 11 in which the filler 20 member is of a refractory material. 16 16 55 153

10. 13. A boiler as claimed in any preceding claim wherein the base of the chamber is defined by a bottom water tank.

11. 14. A boiler as claimed in claim 13 in which the bottom tank is lined with a refractory material. 5 15. A boiler as claimed in claim 13 or 14 in which that portion of the back tank between the bottom tank and th§ inlet to the combustion gas passageway is lined with a refractory material.

12. 16. A boiler as claimed in any preceding claim in which 10 that removable front plate is provided with a socket in which a burner is mounted.

13. 17. A boiler substantially as hereinbefore described with reference to the drawings. Dated this 16th dav of August 1985 CRUICKSHANK AND COMPANY Agents for the Applicants 1 Holies Street Dublin 2.