GB2191279A - Heat exchanger - Google Patents

Abstract

A heat exchanger has a shaft wall (1) which defines a combustion chamber and a flue of a heat source, and a pipe system, for example a pipe coil (3), which encloses the shaft wall (1) and acts as a conduit for heat transfer fluid. The shaft wall (1) is polygonal, preferably square, in cross-section, and has openings (2) formed in corner portions. The pipe system has curved portions, for example convolutions of a pipe coil (3), which extend around the corner portions protrude through the openings (2) into the shaft interior, and are connected to the shaft wall by soldering or welding. <IMAGE>

Description

SPECIFICATION Heat exchanger This invention relates to a heat exchanger comprising a shaft wall, which defines the combustion chamber and the flue of a heat source, and a pipe system, e.g., a pipe coil, which encloses said shaft wall and conducts a heat transfer fluid.

Such a pipe system constitutes an additional heat exchanger for cooling the shaft and on the hot side serves to reduce the losses due to radiation and to increase the efficiency.

Owing to the usual design of gas burners and of the associated blocks of blades installed in the combustion chambers, the shaft which succeeds the combustion chamber has in cross-section desirably the shape of a polygon, preferably of a square or rectangle.

A design of the shaft with rounded corners has the disadvantage that there is a risk of the burner flames striking against the rounded corners so that said portions of the shaft wall will be overheated.

Besides, a relatively expensive transition must be provided between the cornered shaft portion adjacent to the combustion chamber and the primary heat exchanger and the circular shaft portion adjacent to the shaft cooler, which in most cases consists of a pipe coil.

The invention is concerned with a solution to that problem and proposes so to design a heat exchanger of the kind described first hereinbefore that the shaft wall, which is polygonal and preferably square in cross-section, is formed in its corner portions with local openings, and the pipe system has curved portions e.g., convolutions of a pipe coil, which extend around said corner portions and through said openings.

By these measures the invention permits the manufacture of shaft walls which are cornered in cross-section and yet are cooled by one or more pipe coils and the minimum radii which are required for a satisfactory curvature of the pipes can be obtained without difficulty.

For practical requirements, the shaft wall is desirably composed of a selectable number of individual prefabricated shaft wall sections, which are formed with such openings.

An illustrative embodiment of a shaft wall section designed in accordance with the invention is shown in perspective in the single figure of the drawing.

The wall 1 is formed with four openings 2, which are disposed in the corner portions of a shaft wall section. The wall 1 is surrounded by a pipe system, which comprises pipes 3 that extend through the openings 2 and are indicated only in part. Said pipes 3 are curved at least in said corner portions and for this reason protrude in said portions into the interior of the shaft whereas this does not appreciably reduce the cross-section of the shaft.

The illustrated heat exchanger may be made by punching out openings 2 of somewhat oval configuration from a metal sheet or the like flat blank dimensioned for the production of the shaft wall or a shaft wall section 1. The blank is then deformed into the shaft or a shaft wall section 1 with polygonal, preferably square, section, in the corner zones of which these openings 2 are situated. Then the shaft, or a shaft composed from such shaft wall sections 1, is jacketed with the pipe system 3, for example a pipe coil, while the curved sections of the pipe system 3 conducted round the corner zones of the shaft, for example the convolutions of a pipe coil, protrude into the shaft, deform material still standing there and come to rest on the shaft wall 1, in order finally to be connected with this wall, for example by soldering or welding.

1. A heat exchanger comprising a shaft wall, which defines the combustion chamber and the flue of a heat source, and a pipe system, e.g., a pipe coil, which encloses said shaft wall and conducts a heat transfer fluid, characterized in that the shaft wall, which is polygonal and preferably square in cross-section, is formed in its corner portions with local openings, and the pipe system has curved portions e.g., convolutions of a pipe coil, which extend around said corner portions and through said openings.

2. A heat exchanger according to claim 1, characterized in that the shaft wail is composed of a selectable number of individual prefabricated shaft wall sections, which are formed with such openings.

3. A heat exchanger substantially as described herein with reference to the accompanying drawing.

4. A method of making a heat exchanger according to claim 1 or claim 2, characterised in that openings of somewhat oval configuration are punched out of a metal sheet or the like flat blank dimensioned for the production of a shaft wall or a shaft wall section, in that then the blank is deformed into a shaft or a shaft wall section with polygonal, preferably square, section, in the corner zones of which these openings are situated, and in that then the shaft, or a shaft composed from such shaft wall sections, is jacketed with a pipe system, for example a pipe coil, while the curved sections of the pipe system conducted round the corner zones of the shaft, for example the convolutions of a pipe coil, protrude into the shaft, deform material still standing there and come to rest on the shaft wall, in order finally to be connected with this wall, for example by soldering or welding.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Heat exchanger This invention relates to a heat exchanger comprising a shaft wall, which defines the combustion chamber and the flue of a heat source, and a pipe system, e.g., a pipe coil, which encloses said shaft wall and conducts a heat transfer fluid. Such a pipe system constitutes an additional heat exchanger for cooling the shaft and on the hot side serves to reduce the losses due to radiation and to increase the efficiency. Owing to the usual design of gas burners and of the associated blocks of blades installed in the combustion chambers, the shaft which succeeds the combustion chamber has in cross-section desirably the shape of a polygon, preferably of a square or rectangle. A design of the shaft with rounded corners has the disadvantage that there is a risk of the burner flames striking against the rounded corners so that said portions of the shaft wall will be overheated. Besides, a relatively expensive transition must be provided between the cornered shaft portion adjacent to the combustion chamber and the primary heat exchanger and the circular shaft portion adjacent to the shaft cooler, which in most cases consists of a pipe coil. The invention is concerned with a solution to that problem and proposes so to design a heat exchanger of the kind described first hereinbefore that the shaft wall, which is polygonal and preferably square in cross-section, is formed in its corner portions with local openings, and the pipe system has curved portions e.g., convolutions of a pipe coil, which extend around said corner portions and through said openings. By these measures the invention permits the manufacture of shaft walls which are cornered in cross-section and yet are cooled by one or more pipe coils and the minimum radii which are required for a satisfactory curvature of the pipes can be obtained without difficulty. For practical requirements, the shaft wall is desirably composed of a selectable number of individual prefabricated shaft wall sections, which are formed with such openings. An illustrative embodiment of a shaft wall section designed in accordance with the invention is shown in perspective in the single figure of the drawing. The wall 1 is formed with four openings 2, which are disposed in the corner portions of a shaft wall section. The wall 1 is surrounded by a pipe system, which comprises pipes 3 that extend through the openings 2 and are indicated only in part. Said pipes 3 are curved at least in said corner portions and for this reason protrude in said portions into the interior of the shaft whereas this does not appreciably reduce the cross-section of the shaft. The illustrated heat exchanger may be made by punching out openings 2 of somewhat oval configuration from a metal sheet or the like flat blank dimensioned for the production of the shaft wall or a shaft wall section 1. The blank is then deformed into the shaft or a shaft wall section 1 with polygonal, preferably square, section, in the corner zones of which these openings 2 are situated. Then the shaft, or a shaft composed from such shaft wall sections 1, is jacketed with the pipe system 3, for example a pipe coil, while the curved sections of the pipe system 3 conducted round the corner zones of the shaft, for example the convolutions of a pipe coil, protrude into the shaft, deform material still standing there and come to rest on the shaft wall 1, in order finally to be connected with this wall, for example by soldering or welding. CLAIMS

1. A heat exchanger comprising a shaft wall, which defines the combustion chamber and the flue of a heat source, and a pipe system, e.g., a pipe coil, which encloses said shaft wall and conducts a heat transfer fluid, characterized in that the shaft wall, which is polygonal and preferably square in cross-section, is formed in its corner portions with local openings, and the pipe system has curved portions e.g., convolutions of a pipe coil, which extend around said corner portions and through said openings.

2. A heat exchanger according to claim 1, characterized in that the shaft wail is composed of a selectable number of individual prefabricated shaft wall sections, which are formed with such openings.

3. A heat exchanger substantially as described herein with reference to the accompanying drawing.

4. A method of making a heat exchanger according to claim 1 or claim 2, characterised in that openings of somewhat oval configuration are punched out of a metal sheet or the like flat blank dimensioned for the production of a shaft wall or a shaft wall section, in that then the blank is deformed into a shaft or a shaft wall section with polygonal, preferably square, section, in the corner zones of which these openings are situated, and in that then the shaft, or a shaft composed from such shaft wall sections, is jacketed with a pipe system, for example a pipe coil, while the curved sections of the pipe system conducted round the corner zones of the shaft, for example the convolutions of a pipe coil, protrude into the shaft, deform material still standing there and come to rest on the shaft wall, in order finally to be connected with this wall, for example by soldering or welding.