Background of the invention In case of the most simple firing chambers of fireplace inserts and fire stoves, the problem of smoke-soiling of glazed parts is not solved.

This causes a very quick soiling with soot formation on glazed surfaces and, thus, deterioration of visibility of fire in the firing chamber.

Another known solution is fitting of heating devices with specially modified glass the surface of which is coated with a layer of catalytic substance. This substance just speeds up the process of glass self- cleaning but does not prevent depositing of soot on glass surfaces.

Main disadvantage of this design lies in a high price of glass, with the practical cleaning effect being associated with problems as it is necessary to permanently maintain a high temperature so that the mentioned cleaning may take place. In this way, consumption of fuel increases and the heating device cannot run in a saving regime.

Moreover, it is necessary to use hard and well dried wood. Wood species with a higher moisture and/or resin content suppress the mentioned self-cleaning effect completely. Moreover, the catalytic layer is abraded during cleaning and disappears with time.

Another design consists in separating flue gas from glass by a thin layer of air flowing as closely as possible along the glass surface. The air flow enters the firing chamber space at least in one complete length of glazing. A certain barrage preventing soiling is thus formed. A disadvantage of this most often used design is that air flows into the firing chamber as a thin stream of high velocity created by underpressure in the firing chamber and thus it creates the injector effect that draws in and attracts flue gas to the glass vicinity in a greater extent. Consequently, this injector effect dramatically deteriorates the result of the flue gas separation from the glass. This results in soiling the glass in the form of black stripes (tongues) and subsequent reduced visibility of the firing chamber interior. Moreover, as the drawn-in air is also necessary for secondary combustion its sucked amount is limited. The mentioned soiling is again more intensive during burning-out of faintly glowing fuel.

Summary of the invention The above mentioned shortcomings are to a considerable extent removed by the firing chamber, particularly of fire stoves or fireplace inserts, according to this invention the principle of which is that the front and/or side surface of the door wall and/or the peripheral part of the fireplace are fitted with at least one dispersion chamber equipped with an inlet hole, wherein the dispersion chamber space is filled with a porous dispersion material.

The air sucked into the firing chamber passes through the dispersion chamber filled with a porous dispersion material where the drawn-in air is dispersed on a larger area which results in a dramatic reduction of its flow velocity. The air of a reduced velocity dispersed in this way is discharged in the vicinity of glass surfaces where it forms a thick barrage of slowly flowing clean air with a very weak injector effect,

wherein the amount of air necessary for secondary combustion is kept within optimum limits. Just a slight amount of sucked-in flue gas can possibly penetrate the thick layer of clean air to the glass. This means that an optimum amount of secondary air for combustion is provided and a sufficiently thick layer of slowly flowing barrage of clean air with a negligible injector effect is formed.

The main advantage of this design is seen in the fact that glasses of glazed fireplace or fire stove doors, or solid glazed surfaces of these devices are kept clean. It is preferable for a correct function that the dispersion material is metal wool and/or metal dust and/or mineral wool and/or filtration material, that the dispersion chamber is fitted in its lower part with a perforated bottom and that the perforated bottom is made from a fine netting metal material.

Brief description of the drawings The invention will be explained in detail by means of the drawing where Fig. 1 shows the front view of the fireplace insert, including location of the dispersion chamber in the front upper wall of the fireplace door ; Fig. 2 shows the side view of the fireplace insert with partial sectional view where the dispersion chamber is located in the front upper wall of the fireplace door ; Fig. 3 shows the detail of the dispersion chamber with depicted possible air inlet and its dispersion in the firing chamber, and Fig. 4 shows the side view of the fireplace, including location of the dispersion chamber in the peripheral part of the fireplace firing chamber.

Examples of embodiment of the invention

The firing chamber, particularly of fire stoves or fireplace inserts, as an integral part of the fireplace, according to Fig. 1 through 4, is designed in such a way that the front surface of the wall 4 of the door 1 is in its upper frame fitted with one dispersion chamber 2. Fig. 4 depicts location of the dispersion chamber 2 in the peripheral part of the fireplace firing chamber 6. The dispersion chamber 2 is fitted with the inlet hole 7 for supply of fresh air. The lower part of the dispersion chamber 2 is fitted with the perforated bottom 5, preferably made from a fine netting metal material. The dispersion chamber space 2 is filled with a porous dispersion material 3 which is metal wool and/or metal dust and/or another non-combustible porous material.

The firing chamber, particularly of fire stoves or fireplace inserts, with the dispersion chamber 2 serves for keeping clean glass of glazed fireplace or stove doors 1 and/or fixed glazed surfaces of these devices.

Industrial applicability The firing chamber, particularly of fire stoves or fireplace inserts, according to this invention, i. e. with the dispersion chamber, is industrially applicable, particularly for the fire stoves or fireplaces with the glass front, side or opposite surface and can be installed into the existing fireplaces.