The invention concerns a combustion chamber for a gas-fired heat exchanger.

Today, the combustion chamber in gas-fired heat exchangers is either thermally insulated or cooled with a working fluid.

Known from the patent document PL205535 Bl is a device designated for a gas-fired water heater. The combustion chamber of the device is made of an insulating material, such as ceramic, and at least part of the heat exchanger is made of metal, such as copper or aluminum. The combustion chamber and the heat exchanger are connected to each other. The combustion chamber has slots to accommodate the heating elements going through the opposite walls of the combustion chamber through those very slots. The collectors used to connect separate heating elements one to another inside the heat exchanger are installed outside the walls of the combustion chamber.

Known from the patent document PL 172025 Bl is a water heating boiler in which the combustion chamber is fitted inside a double-wall pipe, where flat heat exchanger perforated with a large number of openings through which water gets in between the two wall pipes forms the lower section of the external pipe wall.

Known from the patent document PL396460A1 is a heat exchanger intended for a condensing boiler, fitted with an outer jacket with a combustion chamber installed inside in its upper part, where under the combustion chamber there is a set of vertical pipe elements anchored in sieve walls on both of their ends, and where the upper sieve wall serves as the bottom of the combustion chamber, while the space between the side wall of the combustion chamber and the outer jacket, and the space under the combustion chamber and around the set of pipe elements are

interconnected to form the fluid chamber.

A combustion chamber for a gas-fired heat exchanger according to the invention, open on one side and fitted with a burner, is characterised in that there is a free space formed between its inner and outer jackets to accommodate the mixture of gas and air supplied to the burner, where the latter is fitted with a perforated wall and where there is a ventilator and a gas valve mounted in the outer jacket.

Preferably, the burner is located in the upper part of the combustion chamber and forms a separate part connected to the space accommodating the mixture of gas and air, formed between the inner and outer jackets of the combustion chamber, with an element which supplies the gas-air mixture to the burner.

Preferably, the inner jacket encases the interiour of the combustion chamber on all sides and has a perforated area which is a perforated wall of the burner, where preferably the latter is either formed in the upper part of the inner jacket, or encases the interiour of the combustion chamber on all sides.

Preferably, the outer jacket and/or inner jacket is fitted with a flange for the mounting of the combustion chamber on the heat exchanger subassembly.

Preferably, the perforated wall of the burner is made of a material resistant to high temperatures, preferably of a perforated steel sheet and/or mesh and/or a woven and/or non-woven material.

The structure of the combustion chamber according to the invention allows even pumping of the gas-air mixture through the openings in the perforated wall of the inner jacket into the interiour of the combustion chamber and controlling the flow of the mixture thanks to which it is possible to obtain the requested burning parameters, the size of the flame included, and contain the area of burning within the interiour of the combustion chamber only. Moreover, the gas and cold air pumped into the space between the outer and inner jackets cool the combustion chamber adequately while flowing around the inner jacket. Since the combustion chamber may be given any desired shape, it can be used together with any heat exchanger sub-assembly irrespective of its shape.

These and other characteristics of the invention will be clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached drawings wherein: Fig. 1, Fig. 3, Fig.5, and Fig. 7 show the combustion chamber in the axonometric projection with a view of the inside, installed on a heat exchanger sub-assembly, and Fig.2, Fig. 4, Fig. 6, and Fig. 8 - an axial section of the combustion chamber depicted on Fig. l , Fig. 3, Fig. 5, Fig.7, respectively.

The combustion chamber for a gas-fired heat exchanger is open on one side and on that side it is installed on the heat exchanger subassembly 7. The chamber has inner jacket 2 and outer jacket 1 , between which space 3 is formed to accommodate the mixture of gas and air supplied to the burner 4. There is a ventilator 6 and a gas valve mounted in the outer jacket. The burner 4 is fitted with a perforated wall 5, through which the mixture is pumped into the interiour 8 of the

combustion chamber.

In the first embodiment of the invention, shown on Fig. 1 and Fig. 3, the burner is positioned in the upper part of the combustion chamber and forms a separate part 4. The space 3 to accommodate the mixture of gas and air, formed between the outer jacket 1 and inner jacket 2 of the combustion chamber, is connected to the burner 4 with an element 1 1 C-shaped in cross-section, through which the gas-air mixture is supplied to the burner.

In another embodiment of the invention, shown on Fig. 3 and Fig. 4, the burner is also positioned in the upper part of the combustion chamber and it also forms a separate part 4. The space 3 for the mixture of gas and air which is formed between the outer jacket 1 and the inner jacket 2 of the combustion chamber is connected with bushings 12 through which the gas-air mixture is supplied to the burner.

In yet another embodiment of the invention shown on Fig. 5 and Fig. 6 the inner jacket 2 encases the interiour 8 of the combustion chamber on all sides and has a perforated area in its upper part, which is the perforated wall 5 of the burner.

In another embodiment shown on Fig. 7 and Fig. 8, the inner jacket 2 encases the interiour of the combustion chamber on all sides, where the perforations are made in all walls encasing the interiour and where the perforated area is the perforated wall 5 of the burner.

In all embodiments described above, the outer jacket 1 and/or the inner jacket 2 are fitted with a flange 10 for the mounting of the

combustion chamber on the heat exchanger sub-assembly 7.

In all embodiments described above, the perforated wall 5 of the burner is made of a material resistant to high temperatures, preferably of a perforated steel sheet and/or mesh and/or a woven and/or non-woven material.

The combustion chamber is mounted on the heat exchanger subassembly 7 using the flange 10. The space 3 formed between the outer jacket 1 and inner jacket 2 is filled with air (using ventilator 6) and gas (through the gas valve). Thus obtained mixture of gas and air is then evenly pumped through the openings in the perforated wall 5 of the burner into the interiour 8 of the combustion chamber where it is burned, for example in effect of a spark-over between the electrode 9 and the earth electrode. The mixture pumped into the space 3 between the outer jacket 1 and inner jacket 2 cools the inner jacket 2 and outer jacket 1 of the combustion chamber when flowing around the inner jacket 2, whereas the hot combustion gases get into the fuel exchanger sub-assembly 7, where it gives up their heat to the heated agent.