Boiler

Abstract

A boiler with a boiler casing carrying a heat exchange medium and a double wall bulkhead in the casing receiving the heat exchange medium therefrom and defining a combustion chamber. A fuel burner is arranged at the inlet of the combustion chamber and produces gases. A double wall bulkhead having a baffle wall portion opposite the inlet and two arcuate lateral wall portions extending from the baffle wall portion towards the inlet also receives the heat exchange medium from the casing and is positioned in the combustion chamber to define a baffle chamber reflecting and reversing the combustion gases to combustion gas conduits laterally adjacent the lateral arcuately shaped bulkhead wall portions. The baffle chamber and the lateral combustion gas conduits have the same height, and an exhaust flue receives the combustion gases from the conduits at the outlet of the combustion chamber.

Description

BACKGROUND OF INVENTION

The present invention relates to water boilers.

Boilers having a casing which conducts heated media, e.g., water, and in which a combustion chamber is formed by a screen or wall about which run heating gas flues are well known. To attain optimum combustion values, a good intermixing of the combustion air with the fuel, which may be oil or gas, in the burner or burner head is absolutely necessary. Good intermixing is, for instance, obtained if the blower of the burner produces a sufficiently high pressure. Generally, it is possible to produce the desired pressure in the combustion chamber only after a period of operation of the burner. However, it is sometimes possible to design the burners in such a way that from the very outset they produce a specific combustion chamber pressure. In either event, the burners must be in a position to overcome the particular thermal resistance in the boiler before efficient operation is obtained. If the boiler is consistently designed for excess pressure in the combustion chamber, considerable economies in the heating surfaces are obtained. This is particularly so if the boiler is correctly designed from its flow aspect and if the ratio of combustion chamber volume to the flues and in particular the heating surface of the combustion chamber to the heating surface of the flues is at a calculated ratio, as well as if the transfer cross-sections from the combustion chamber to the flues are sufficiently large.

In combustion chambers of the known and conventional type, these fundamental criteria are only taken into consideration with a corresponding increase in production costs. In addition, special cleaning ports are required, causing the fitting of the external boiler insulation to be correspondingly costly. The arrangement, coordination and design of combustion chamber and flues generally do not permit the rapid welding of parts and substantially prevent the automatic fabrication of the boiler into a unitary structure.

It is, therefore, an object of the present invention to remove these difficulties, i.e., to provide a boiler which, while taking into account the above-indicated requirements, permits a simple and therefore cost-saving manufacture. It is also an object of this invention to provide a boiler carrying a head exchange medium. A double wall bulkhead receives the heat exchange medium from the casing and defines a combustion chamber having an inlet and an outlet opposite to the inlet. A fuel burner is arranged at the inlet and produces combustion gases in the combustion chamber. A double wall bulkhead having a baffle wall portion opposite the inlet and two arcuate lateral wall portions extending from the baffle wall portion towards the inlet also receives the heat exchange medium from the casing and is positioned in the combustion chamber opposite the fuel burner so as to define a baffle chamber reflecting and reversing the combustion gases to combustion gas conduits laterally adjacent the lateral arcuately shaped bulkhead wall portions. The baffle chamber and the lateral combustion conduits have the same height. An exhaust flue for the combustion gases is arranged at the outlet and receives the combustion gases from the conduits.

Full details of the present invention and its advantages are set forth in the following description of certain now preferred embodiments thereof.

BRIEF DESCRIPTION OF DRAWING

In the accompanying drawing

FIG. 1 is a vertical section through a boiler constructed in accordance with the present invention and showing the combustion chamber and the fluid storage chamber mounted above, the section being taken along line I--I of FIG. 2;

FIG. 2 is a horizontal sectional view taken along line II--II of FIG. 1, showing in plan view the interior construction of the boiler;

FIG. 3 is a sectional view similar to that of FIG. 2 showing a modified embodiment of the interior boiler construction; and

FIG. 4 is a sectional view similar to FIGS. 2 and 3 showing a third embodiment.

DETAILED DESCRIPTION

The boiler is only schematically shown in all of the figures, omitting those well known and conventional features, such as feed pipes, conduits, sources of fuel, valve mechanisms and other details, which are known to those skilled in this art.

As seen in FIGS. 1 and 2, the boiler comprises a combustion chamber 1 above which a consumption water storage tank 3 is located. The two units are enclosed in a boiler casing 2 in which a liquid heating medium is maintained. The combustion chamber 1 is enclosed by upper and lower plates 5 and 6 respectively and vertical water carrying double walls 2'. This combustion chamber is further divided by double wall bulkhead or screen 7 which is arcuately, i.e., generally oval, shaped but spaced from the double walls 2' and open at one end, the bulkhead defining a central baffle chamber and a laterally surrounding combustion gas conduit 4. In the embodiment shown in FIG. 2, an additional double wall water carrying bulkhead 7' is provided so that a second combustion gas conduit 4' is formed along the lateral walls 2' of the combustion chamber. The outer double walls 2' are integrally secured to the front wall 10' and to the rear wall 10, respectively, the front wall defining inlet 8 and the rearwall defining an outlet 9 leading to an exhaust flue.

The double wall bulkheads 7 and 7' extend for substantially the entire height of the combustion chamber and define gas intake openings 14 communicating with the baffle chamber near the inlet 8 and a terminal portion communicating with the outlet 9 in the rear wall 10 of the boiler casing. When the additional double wall 7' is employed, it is provided with an interruption or opening 15 which allows the interior gas conduit 4 as well as the exterior gas conduit 4' to communicate with the exhaust flue 9.

Apart from the exhaust flue 9, the combustion chamber 1 is preferably provided with only the one other opening 8 extending through the casing 2 and located at the front of the combustion chamber. The opening 8 also extends the entire height of the casing and is closed by a door or other suitable closure member 13 which carries or supports a burner-blower 12, conventionally gas or oil fed. Because the opening 8 and the door 13 extend substantially the height of the combustion chamber 1, the entire interior of the combustion chamber is readily accessible. Since the inlets 14 to the gas conduits 4 and 4' are adjacent to the front end of the combustion chamber, they, too, are readily accessible when the closure member 13 is removed.

A liquid medium inlet KV and a liquid medium return outlet KR are provided for supplying and reducing the quantity of liquid heat exchange medium (preferably water) located within the casing 2 and surrounding the combustion chamber and the storage tank 3. The storage tank 3 is itself provided with cold water inlet WI and hot water outlet WO. The water in the double wall bulkheads 7 and 7' is caused to flow upwardly into the area surrounding the storage tank 3 through openings 11, formed in the upper plate 5 and lower plate 6. The openings 11 are coextensive with the cross section of the bulkheads 7 and 7' so that the combustion chamber is made watertight. These plates 5 and 6 may also be made slightly curved so as to provide improved flow and pressure characteristics.

The interruption or opening 15 in the additional double wall bulkhead 7' can also have a height substantially equivalent to the height of the combustion chamber 1 although this is not absolutely necessary. On the other hand, the interruption 15 may be made only in the lower half of the bulkhead 7' so that a gas from the inner conduit 4 may be caused to flow downwardly before reaching the exhaust flue 9, while the gases in the outer conduit 4' will have an upward component. This gas flow may be aided by the use of conventional sheet metal guides or plates located in the conduits.

The sheet metal guides or plates may be used even when the interruption 15 extends the entire height of the combustion chamber.

In FIGS. 3 and 4 there is once again shown a combustion chamber defined by bulkhead 2' and having an interior baffle chamber defined by substantially U-shaped double wall bulkhead 7, substantially as shown in FIG. 2. The base of the bulkhead 7 is located in front of the flue chimney 9. The burner inlet 8 is shown although the closure member 13 and the burner 12 are omitted.

Between the side arms of the double wall bulkhead 7 and in the interior of the combustion chamber 1 of FIG. 3 there is located an additional pair of double wall water carrying bulkheads 16 having front edges 17 disposed adjacent the front wall of the boiler, leaving narrow gaps 18 which serve as gas by-passes. In FIG. 3, the front wall of the boiler is provided with double walls 19 which are also water bearing. In FIG. 4, the interior water carrying bulkheads 16 are extended beyond the front edges 17 to communicate with the forward wall portions of the front of the boiler which are here indicated as 19'. In the embodiment of FIG. 4, the by-pass gap 18 is omitted. The direction of gas flow, as seen in FIG. 3, is from the opening 8 substantially to the rear of the baffle chamber (although some gas passes through by-pass 18), thence through a first pair of conduits 4 between the interior bulkheads 16 and bulkhead 7, following a tortuous path between the bulkheads 7 and the exteriour bulkheads 2' until it reaches the rear wall 10 and exits through the flue chimney 9. A similar flow path is seen in FIG. 4, except that, in the absence of the gaps 18, there is no by-pass of gas.

In addition to the opening 8 in the embodiment of FIGS. 3 and 4, which opening may extend substantially the height of the boiler, the front wall may be provided with separable or removable covers 20. The covers 20 may or may not extend the entire height of the boiler. Shields, guides, ridges or other baffle members 21 may be inserted, as desired, between the walls of the bulkheads 7 and 2' and/or the bulkheads 7 or 16. These flue guide members insure the proper flow direction and control the flow resistance within the boiler.

In each of the embodiments shown, water is introduced by conventional means through inlet KV passing into the bulkheads 7, 7' and 16 as well as the outer bulkheads formed by the casing wall 2 and the rear casing walls 10 and/or the front casing wall 19'. The burner 12 is caused to heat the combustion chamber 1 of the boiler with the gases passing through the conduits 4 and 4' about and between the bulkheads containing the water. In each of the embodiments shown, there are at least two water carrying walls forming a gas flow path from the baffle chamber reversing the flow of gas coming from the burner and then back toward the flue 9. Preferably, there are three substantially concentric bulkheads containing water located symmetrically about the axes of the boiler chamber. These plural bulkheads provide a tortuous flow path for the gases and an extremely large area for heat transference from the heated gases to the liquid heating medium. The heated liquid is then caused to flow upwardly into the casing about the storage tank along the path shown by arrows A where the heat is transferred to the water in the storage tank 3. Meanwhile, the exhausted gases exit along the path shown by arrows B through the flue chimney 9.

The concentric location of the bulkheads as well as their proximity to opening 8 and the door 13 (as well as to the secondary closure doors 20) permit the interior of the boiler to be readily cleaned from the front of it and avoid the need for the provision of additional openings and doors into the sides or rear of the boiler.

It will be obvious that it is possible to obtain optimem combustion values and a good intermixing of the combustion air with the fuel in the combustion chamber. The concentric bulkhead walls and the tortuous flue path provide a controlled environment for producing a predetermined and desired pressure within the boiler itself. The flow aspects of the boiler can be correctly designed and the ratio of combustion chamber to flue and particularly the heating surfaces and transfer surfaces can also be predetermined to obtain the optimum advantages.

Such boilers can be produced at low cost because the boiler walls and the bulkhead walls can be subjected to pressure loading without having bolts or other stiffening means. Manufacturing costs are also reduced by making all the boiler heating surfaces accessible through the single cleaning port, namely a closure or door 13 which also carries the burner. In this case, the boiler requires no openings for cleaning the flues or other heating surfaces on either the back, top or longitudinal sides. In those rear or side areas, the boiler also requires no openings for the removal of the combustion residues.

According to the invention, the combustion chamber can be either oval or circular in horizontal cross-section, so that the combustion chamber walls can be curved and thus are capable of being pressure loaded. The wall thickness need not be made larger than is necessary to resist corrosion. The combustion chamber is divided by a water carrying double wall bulkhead 7 or 16 which forms a screen defining a baffle chamber. The outer wall of the combustion chamber forms with the nearest water carrying bulkhead one or several combustion gas or flue inlets which extend parallel to the combustion chamber and surround it concentrically. Thus, the combustion chamber heating surface is easily adapted to the combustion gas flue size because, if in a particular model the boiler is made high overall, the combustion chamber will also be correspondingly high and will offer a larger heating surface. The height of the boiler flues, transfer surfaces, etc., are all in direct correspondence. The passages have a larger heat transfer surface area than the inside of the combustion chamber.

If the boiler is made high the heat transfer cross-section from the combustion chamber to the flues is automatically made larger. This is extremely important in order to keep the flow resistance of the combustion gases as low as possible on passing from the combustion chamber into the flues. To insure pressure in the combustion chamber, baffle members for guiding the gases are inserted in the flues.

Boilers with a lower capacity can be made of circular cross-section. The relationship between the combustion chamber and the flues, i.e., the transfer cross-sections from the combustion chamber to the flues, is very favorable to such construction and ease of cleaning is ensured in the same way as with boilers having an oval combustion chamber.

The upper and lower closure (plates 5 and 6) of the combustion chamber and the flues can be made in two ways: firstly, continuous plates can be provided at the top and bottom having corresponding apertures to the bulkheads; or, secondly, one wall of the bulkheads can be chamfered at the top and bottom and placed against the other wall and welded at the resulting edges.

While fundamentally adhering to the constructional principle described, the embodiments of FIGS. 3 and 4 have a further advantage in that they provide boilers with a large thermal capacity.

The variants shown, namely, the front edges of the addition side walls placed just in front of the wall carrying the burner or the additional side walls made integral with a water carrying front wall, have other advantages.

The first variant has the particular advantage that the pressure wave caused on starting up the boiler can largely flow away directly laterally through the gaps between the front edges of the side walls and the boiler front wall.

In the second variant, in horizontal cross-section three water carrying bulkheads are mounted one within the other. Obviously, the boiler according to FIGS. 3 and 4 and its variants offer greater possibility for using flow guide baffle plates, vortex devices or the arrangement of wall ridge stampings to control resistance.

It is also possible for the lateral bulkheads to be arranged so that the gas flues decrease in cross-sections, adapting the flue passages to the increasing reduction in volume of the gases occuring when they cool.

Claims

What is claimed is:

1. A boiler using a fluid fuel comprising

1. a boiler casing carrying a heat exchange medium,

2. a double wall bulkhead receiving the heat exchange medium from the casing and defining a combustion chamber having an inlet and an outlet opposite to the inlet,

3. a fuel burner arranged at the inlet and producing combustion gases in the combustion chamber,

4. a double wall bulkhead having a baffle wall portion opposite the inlet and two lateral wall portions arcuate in horizontal cross section and extending from the baffle wall portion towards the inlet, said bulkhead receiving the heat exchange medium from the casing and positioned in the combustion chamber opposite the fuel burner so as to define a baffle chamber reflecting and reversing the combustion gases to combustion gas conduits laterally adjacent the lateral arcuately shaped bulkhead wall portions,

a. the baffle chamber and the lateral combustion gas conduits having the same height, and

5. an exhaust flue for the combustion gases arranged at the outlet and receiving the combustion gases from the conduits.

2. The boiler of claim 1, further comprising an additional double wall bulkhead receiving the heat exchange medium from the casing and positioned between the first-named bulkhead defining the combustion chamber and the second-named bulkhead defining the baffle chamber, the additional bulkhead being interrupted in the range of the exhaust flue.

3. The boiler of claim 2, further comprising a pair of horizontally extending sheet metal walls interconnecting the bulkheads, the sheet metal walls defining openings permitting the heat exchange medium to enter the bulkheads from the casing.

4. The boiler of claim 1, further comprising a pair of further double wall bulkheads receiving the heat exchange medium from the casing, the further bulkheads being positioned within the baffle chamber symmetrically laterally adjacent the arcuately shaped bulkhead wall portions on either side of the fuel burner inlet.

5. The boiler of claim 4, wherein the further bulkheads extend towards the inlet and adjacently thereto, leaving a gap between forward ends of the further bulkheads and the inlet.

6. The boiler of claim 4, wherein the further bulkheads extend to the inlet and their respective ends are spaced apart to define the inlet.

7. The boiler of claim 1, wherein the further bulkheads are so positioned in respect of the arcuately shaped bulkhead wall portions that they define tapering combustion gas conduits.