The present invention relates to a device for boosting combustion, and specifically a device, which is used in a firebox, in which a solid fuel is used.

When burning a solid fuel, particularly wood, in a firebox, for instance to heat a sauna stove or in a boiler plant, the efficiency of the combustion depends on many different factors. One of the most important factors is the quality of the fuel, which, in the case of wood for example, is the moisture content of the wood. Another important factor is the effective supply of air for the combustion event. Other factors, which have an effect on the combustion event, include, for example, the grate structure. An important aspect of the structure is for pieces of firewood placed in the firebox to be unable to obstruct the passage of air.

An improved grate construction, the operation of which has been shown in practice to be excellent, is known from Finnish patent application 20095917. The said construction consists generally of a corrugated grate plate, which is equipped with holes to lead combustion air effectively to the combustion zone.

Though the said grate construction is indeed efficient in terms of combustion, it can be further improved by eliminating one drawback, i.e. the fact that the pieces of firewood tend to pack against the walls of the firebox and thus prevent efficient combustion. Of course, the same drawback affects nearly all other types of grate.

Thus, the present invention in intended to create a device, by means of which the operation of particularly the grate construction disclosed in patent application 20095917 can be further improved. In addition, several solutions are known, in which the wood to be burned is packed in a separate frame, in which the wood is then burned. The frame structure protects the wood on one side from making contact with the wall of the firebox, should it be taken close to the wall. However, packing requires additional operations, which take up both time and other resources. Combustion in a package is also in a certain way inefficient, nor can optimal combustion conditions be achieved with the aid of it.

The present invention is also intended to bring an improvement to the

aforementioned combustion solution.

The aforementioned and other advantages and benefits of the invention are achieved in the manner described as characteristic in the accompanying Claims. In the following, the invention is described in greater detail with reference to the accompanying drawing, which show one well regarded embodiment of the invention.

Figure 1 shows the device according to the invention, which can be called, for example, a heat rod, seen from three different directions;

Figure 2 shows the use of devices according to the invention in connection with a grate, seen at an angle; Figure 3 shows a straight side view of the use of the device according to the invention, in the situation according to Figure 2; and

Figure 4 shows a front view of a firebox structure, in which the principles of the invention are used.

Thus, Figure 1 shows the device according to the invention, seen from three directions. In principle, the device 1 is formed of three parts, of which the main part in a rod-like part 2, at the end of which is a bent portion 2', and a part 3 joined to the bent portion 2', by means of which the device is stabilized laterally in position, and a part 4 crosswise to these, which determines the position of the device relative to the grate, in connection with which it is installed.

At this stage, it should be mentioned that the device is shown as being made from a rod-like material with a circular cross-section, but it should be obvious even without being stated separately, that a bar-like material with a square or rectangular cross-section would be an equally practicable shape.

It can be seen clearly from Figure 2, how the device according to the invention is installed, for example, in connection with the grate structure according to the patent application referred to above. As can be seen from Figure 2 and

particularly from Figure 3, the grate 5 is formed from a shape with a corrugated cross-section, in which there are holes/openings in both the top 6 and the bottom 7 of the corrugations.

In the lower part of the dropping sides of the edge-most corrugation of the grate, there are also holes/openings 8, the general shape of which is elongated in the up-and-down direction. The device according to the invention is intended to be installation in these openings 8, as shown in Figures 2 and 3. In Figure 2, the device 1 at its right-hand lower corner is in the installation stage and it is quite apparent from it that the rod-like device is placed in the hole 8, in a position tilted towards the central part of the grate, from which it is raised to an essentially vertical position, so that the cross part 4 determines the depth to which the device 1 can sink:

The shape and size of the bent portion 2' and the additional part 3 attached to it are together such that, in the tilted position the said parts fit easily into the opening 8, but moving the device 1 to an essentially vertical position means that the edges of the parts 2' and 3 fit against the edges of the opening 8 and stop further rotation forwards from the essentially vertical position. Depending on the situation and installation and its tolerances, support for the device 1 can be obtained mainly also from the firebox walls. It is obvious that the thickness of the said parts 2' and 3 corresponds essentially to the internal dimension of the opening 8.

Changing the devices 1 is easy, the device is rotated to a position tilted towards the central part of the firebox and then lifted out, and is set back in place in the reverse sequence. Thus, the firebox can be cleaned easily. As can be easily deduced from Figures 2 and 3, the devices 1 settle against the walls of the firebox on both of its sides. When pieces of firewood are placed on top of the grate 5, they cannot settle against the firebox walls due to the rod-like parts 1 , for which reason in all circumstances channels for the free passage of combustion air remain in the immediate vicinity of the firebox walls. When wood is added, it also cannot cool the firebox wall, for which reason the heating effect of the fire is maximal.

It should also be noted that the provision of combustion air is unrestricted next to the firebox wall, which remains unobstructed, for which reason ignition of the wood or similar solid fuel is efficient in the edge areas of the firebox in the lighting stage.

When using the device according to the invention, the firebox walls remain clean, because poorly burning wood does not lie against them causing pitch to adhere to them, and because scale too burns effectively off the firebox walls. For this reason, the firebox cleaning interval is lengthened significantly. The rod-like devices according to the invention also in no way prevent the efficient transfer of thermal radiation to the firebox walls, so that the combustion efficiency is maximal. It is obvious that the manufacturing material of the devices according to the invention is metal, especially steel.

Above, the parts 2' and 3 are described as being separate parts, attached to each other, but it is obviously without being stated separately, that the parts 2' and 3 can also be combined to form a single part, for example, by shaping the lower end of the device to form a single integral part with a rectangular cross-section.

If the conditions of using the device according to the invention are viewed in Figures 2 and 3, it seems relatively certain that the correspondence of the parts 2' and 3 described above to the shorter edges of the elongated opening/hole 8 does not have to take place when the dimensioning is otherwise performed in such a way that the rod-like devices 1 lean against the firebox walls in the desired position. The weight of the devices 1 themselves will hold them in place anyway. It is apparent from Figures 2 and 3 that the joint between the device 1 and the wall of the grate takes place takes place in a position with an angle of nearly 45 degrees. This appears to be the situation quite often, but in no way always, because the tilt of the side wall of the grate, for example, can easily vary. The structures are dimensioned in all ways always in a manner appropriate to the desired application.

Figure 4 shows an environment according to the invention. This could be described as, for instance, a firebox 9, from which the door and possibly part of the front wall have been removed to improve visibility. The rods 1 according to the invention have been placed in the edge areas of the grate 5 in the manner described above, so that they lie against the inner wall 10 of the firebox. The pieces of wood 11 cannot settle against the inner wall, but always remain separated form the wall by the thickness of the rod-like element 1. This means that combustion air can flow between the rods 1 , maintaining and boosting the combustion zone and the efficient transfer of heat in the edge areas too. The firebox remains clean and its cleaning requirement is small.

Unlike in known solutions, pieces of firewood can be thrown into the firebox in the same way as in conventional solutions. No pre-packaging or tying, or placing of a package in a suitable location is required.