FI114238B - Hearth - Google Patents

Abstract

The invention relates to a fireplace comprising a core (2) with a firebox (3), and a shell (1) arranged at a distance from the core in such a manner that there is a space (5) between the core and shell. So that in conventional batch-type burning, the fireplace was be able to emit heat to its surroundings more uniformly and heat emission continued longer than in the prior art fireplaces, heat regulation means (4) are arranged in the space (5) between the core (2) and shell (1) to control the amount of radiation heat transmitted from the surface of the core towards the inner surface of the shell.

Description

114238

Hearth

Background of the Invention

The invention relates to a fireplace comprising an inner part having a fire chamber and a casing disposed at a distance from the inner part such that there is a space between the inner part and the casing. The bark is at a distance from the interior, inter alia, to allow transitions due to differences in thermal expansion of the shell and interior without damaging the structure of the fireplace.

Fireplaces with this structure are very common. Often they are of the type fireplace type.

10 An essential feature of a fireplace is the ability to release heat to its surroundings (typically to a room). The heat output from the fireplace to its surroundings depends on the size (surface area) of the fireplace shell and the temperature of its surface. The heat output of a batch fired fireplace will vary over time during and after the heating period. At the beginning of the heating, the surface temperature of the as-15 rises approximately directly in proportion to the time used for heating. When heating is complete, the bark temperature will continue to rise as the heat from the hot interior is transferred to the relatively cold bark surrounding it. After the interior has raised the shell surface temperature to its peak, the shell surface temperature begins to slowly decrease over time.

The unit used for heating is generally desired to provide as uniform a heat output as possible. The fireplace as a heating unit is such that this feature is difficult to realize in practice because it requires that the fireplace has to be heated at short intervals, which is laborious. One desirable feature of a fireplace 25 is that it would release heat at high power and for as long as possible per heating. A large fireplace is better in this respect than a small fireplace. In particular, a small fireplace has the disadvantage that it has to be heated to such a high temperature that it raises the room temperature at least momentarily to an uncomfortably hot temperature in order to achieve a long-term heat release per heating cycle.

Brief Description of the Invention

It is an object of the present invention to provide a fireplace which has a significantly smoother heat transfer ability to its surroundings than in known fireplaces and which also allows the heat generation per heating cycle to be more efficient and longer than in known fireplaces. This object is achieved by a fireplace according to the invention, characterized in that the space between the inner part and the casing is provided with heat control means for controlling the amount of radiant heat transmitted from the inner surface towards the inner surface of the casing.

Preferably, the thermoregulatory means comprises plate-like elements, and a pivoting mechanism for positioning the plate-like elements in the space between the insert and the shell in a first position wherein the levels defined by the plate-like the defined planes are at an angle to the plane defined by the inner part, in which, in the second position, the planes defined by the plate-like elements do not provide said inhibition of radiant heat transfer. If several plate-like elements are used, it is possible to provide the heat control means in a small space inside the fireplace, whereby the distance between the inner part and the shell can be small. The relatively small distance, for example 20-50 mm, between the interior and the shell is important because otherwise the radiant heat will not be allowed to efficiently transfer te-20 from the interior to the shell when desired, typically after the fireplace cools below a certain temperature. Heat transfer may also be desired in the early stages of heating, in order for the fireplace to reach its maximum temperature as quickly as possible.

Preferably, the heat control means for the fireplace comprises a venetian blind, wherein the venetian blind slats form said plate-like elements. The slatted blind may have the same structure as a conventional louvre used in apartments, whereby the louvre slats are horizontal. It also has the advantage of being easily raised and lowered to the desired height, which can influence the heat release properties of the fireplace.

Alternatively, the heat control means may comprise a vertical lamella blind, the lamellae forming said lamellar elements. The vertical blinds can have the same structure as the vertical blinds used in offices. One advantage of the vertical lamella blind is that it can be designed in such a way (vertical bearing) that the need for a force-35 to adjust the angle of the lamellae is very low, whereby the blind 3 turns. 114238 can be accomplished with a small actuator and even automatically.

Said plate-like elements are preferably made of heat-reflecting (highly) reflecting and insulating material, such as hollow pieces of aluminum or steel.

According to one embodiment of the invention, the material of the thermoregulatory device may be selected so as to be poorly permeable to thermal radiation at high temperatures but highly permeable to thermal radiation at lower temperatures. Such a design provides automatic radiation heat control if the bark is prevented from becoming unnecessarily hot, but allows heat radiation to pass from the inside of the fireplace to the bark at low bark temperatures.

A very simple implementation of the heat control means can be achieved by a solution in which the heat control means comprises 1 to 4 plate-like elements movable from the first position to the second position, in their second position, they are in a position where they are prevented from providing said inhibition of radiant heat transfer. The fireplace shell may then have an opening (s) for at least partially removing the plate-like elements from the space between the interior of the fireplace and the shell. The more elements included in the heat control means, the more precisely the amount of heat radiation transmitted can be controlled.

According to a quite simple embodiment, the heat control means comprises a first plate-like element and a second plate-like element which is movable from a first position to a second position relative to the first plate-like element. Then, the first and second plate-like elements have a plurality of holes such that the second plate-like element 30 is arranged to cover the holes in the first plate-like element ··· when the second plate-like element is in its first position and the holes of the second plate-like element with the element in its second position to allow the transfer of radiant heat.

Preferred embodiments of the fireplace according to the invention are disclosed in the appended claims 2-16.

• · 5 114238 4

The main advantages of the fireplace according to the invention are that in conventional batch firing it has the ability to release heat to its surroundings more uniformly and for a longer time than known fireplaces of the same mass and maintaining high heat transfer efficiency. This allows better utilization of the heat stored in the rock material of the tu-5 adder.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail by means of preferred embodiments with reference to the accompanying drawing, in which Figure 1 illustrates heat transfer in a fireplace 10 and a conventional fireplace according to the invention, Figure 2 illustrates the structure of a fireplace according to the invention; Figure 5 illustrates in more detail the heat control means in the fireplace of Figures 2 and 3, Figures 6 and 7 show an alternative embodiment of the heat control means shown in Figures 2 and 5, Figure 8 shows a structure similar to Figure 6, Figure 10 illustrates a top view of the structure of Figure 8.

DETAILED DESCRIPTION OF THE INVENTION

The curves A and B in Fig. 1 illustrate how the thermal power, P, changes as a function of time, t, in a fireplace provided with heat control means according to the invention. The hearth is rocky and consists of an interior and a surrounding shell. Both the dashed curve A and the solid line curve B illustrate how the heat output changes over time as the fireplace is heated batchwise in the same way and with the same amount of wood.

The thermal power, P, changes according to curve A when the heat control means (the construction of which is explained below) are adjusted to an open position where they do not substantially prevent heat transfer from the inside of the fireplace to the fireplace shell.

Curve A corresponds to the change in thermal output of a conventional fireplace without heat control means over time. Curve B shows the change in thermal power, Pb, of the firebox according to the invention as a function of time, t, as the heat control means 35 is adjusted as a function of time. In curve B, the heat transfer means are initially open (or alternatively closed) for a short time, after which they are closed and kept at least partially closed for a certain time, after which the heat control means are opened so that they are finally fully open.

The shape of the curves A and B is substantially different. Curve A5 represents the rapid heating of the fireplace to its maximum power PAmax, for example, at a temperature of 80 ° C, after which the shell begins to cool so that cooling is quite steep for an extended period of time. Curve B illustrates a situation in which the heat control means of the fireplace is kept closed for at least t1 -12 so that the heat output of the fireplace cannot rise to PAmax but 10 increases only to the maximum power PBmax, which is significantly lower than the power PAmax. approximately constant over a period of h-13, after which the thermal power begins to decrease, but only slightly due to the fact that the heat control means are kept open after t3, whereby the interior of the fireplace effectively transfers heat to the fireplace shell. At the end of heating and after time t2, curve B is higher than curve A, which means that the heat output from the fireplace after time t2 is significantly higher than that of curve A, and the heat dissipation also continues for a longer time. Because curve B falls more slowly than curve A, heat transfer to the environment is also smoother. For both curve A and curve B, the amount of heat released to the environment is the same. However, the essential difference is that, in the case of curve B, the thermal energy corresponding to the bevelled surface area Aa is not introduced during the time period t0 -12, but only after t2, which is illustrated by the bevelled surface area AB. In order for the fireplace according to the invention to release heat to the environment as evenly as possible, the heat control means are kept open during the initial heating period t0-ti, kept closed during t1 -13 and kept open after t3. The following describes heat control means which enable said adjustment.

Figures 2 and 3 illustrate the construction of a fireplace according to the invention. In Figure 2, the fireplace is shown open with most of the fireplace shell 1 removed. The figure thus shows the interior 2 of the fireplace, which includes the furnace 3, and the lower end of the casing 1.

Reference numeral 4 denotes a heat shield which is mounted on the side of the fireplace and which can be used to control the amount of radiant heat transmitted from the inside of the fireplace 2 towards the 35 bark 1. The venetian blind 4 is fixed at the upper edge of the inner part 2 at the height of the ash of the fireplace. There are several venetian blinds, cf. 114238 6 vip 4, which shows that there are venetian blinds on all sides of the fireplace (on the back, on both sides, and in the front). For the sake of simplicity, only one venetian blind 4 is shown in Fig. 2. The venetian blinds 4 extend down to the lower limit of the furnace 3, although in some applications it is sufficient that their lower edge is at a distance of 0-3,500 mm from the lower limit of the furnace. Also on the front wall of the fireplace, the lower edge of the venetian blind can extend up to the lower limit of the furnace 3, since the venetian blind can be easily lifted out of the way at the firebox door.

The venetian blinds 4 remain in the space between the casing 1 and the inner part 2, illustrated by reference numeral 5. The distance S between the inner part 2 and the casing 1 (see FIG.

Fig. 5) is preferably 5 to 30 mm, but may be in the range 5 to 90 mm. If the distance is too great, the interior 2 of the fireplace will not be able to efficiently transmit radiant heat to the casing 1, which is desirable in some application. As a result, in practice, the distance S is at most about 300 mm.

When the venetian blind 4 is closed, its planar slats 13 overlap substantially parallel and vertical to prevent radiant heat from being transferred from the interior 2 to the shell 1. When the venetian blind 4 is in the open position, the planes of the slats 13 are substantially horizontal with large openings between them. allow radiant heat to be transferred from the si-20 core 2 to the inner surface of the housing 1. The position, i.e. angle α, of the slats 13 of the venetian blind 4 is made to be adjusted by means of a rotatable adjusting rod 6 on the outside of the fireplace shell, cf. Figure 3.

Reference numeral 7 in Fig. 3 indicates the control rod for the venetian blind on the front surface of the fireplace.

When the Venetian Blinds 4 are held in the closed position, the temperature of the fireplace ash surface 1 follows the curve B of Figure 1 over the time period ti -13. If the Venetian blinds 4 are kept open, the fireplace surface temperature follows the curve A of Figure 1.

Figure 5 shows in greater detail the structure of the venetian blinds 4 mounted on the flanks 30 of Figure 2. Venetian blind 4 is a conventional type of indoor blind. Thus, in addition to the adjusting rod 7, it comprises two strings 8, by means of which the lower edge 9 of the blind (see Fig. 2) is obtained at the desired height. In this context, it is unnecessary to describe the structure in greater detail, since it is generally known. Naturally, the materials of the venetian blind 35 must be selected so that it has sufficient temperature resistance.

Turning the knob 10 of the adjusting rod 6, the slats 13 are obtained in the desired position. Hole 1 is provided with holes for adjusting rod 6 and cords 8.

In Fig. 5, the slats 13 of the venetian blind 4 are mounted at an angle α relative to the vertical plane defined by the inner part 2 such that the slats reflect the radiation from the inner member 2 obliquely downwards towards the inner member, illustrated by the arrows in the figure. Since the inner member 2 from the top is hotter than the lower one, said position of the slats is capable of compensating for the temperature difference between the upper member and the lower member of the inner member 2. This is an advantage as it can help to ensure that the fireplace radiates heat as evenly as possible.

Fig. 5 further shows that the venetian blind 4 is arranged closer to the casing 1 than to the inner part 2. The vertical center of the venetian blind 4 is at a distance L from the inner surface of the casing 1, whereby said center is at a distance The distance L is 5-20 mm.

In some cases, it may be necessary to direct heat from the space 5 between the interior part 2 and the ceiling 1 to the room space. For this purpose, openings are made in the lower part and the upper part of the casing 1 which can be closed by the hatches 11 and 12, see fig. Fig. 3. The position of at least one of the hatches 11, 12 is adjustable to control the amount of air flowing through the hatch opening, the hatch acting as a valve to control the amount of heat transferred from the hatch to the room. The opening of the door 12 is shown in dashed line in Figure 5 and is indicated by reference numeral 14.

Figures 6 and 7 show an alternative hearth to the embodiment of Figures 2 and 5. Figures 6 and 7 follow the same reference numerals as Figures 2 and 5. As in Figure 2, the fireplace shell T of Figure 6 is the only one shown; 25, so as to reveal the structure of the interior of the fireplace and the heat control means 4 '. In the solution of Figure 6, the temperature control means comprise a vertical lamella blind 4 '. For the sake of simplicity, only one vertical vertical blind 4 'is drawn in the figure, although they can advantageously be present on all the main walls of the fireplace (as in the solution of Fig. 2). The vertical lamella blind 4 'can have the same type of structure as conventional vertical lamella blinds used in apartments, such as commercial apartments. Of course, the temperature resistance must be sufficient, which is taken care of by the right choice of materials. The planar lamellas 13 'of the vertical lamella blind 4' can be superimposed so that heat cannot be transferred from the inner part 2 'to the shell T by radiation. In this case, the plane formed by the la-35 bellows 13 'follows the direction of the fireplace surface. The lamellas 13 'can be rotated to a position where they are substantially perpendicular to the surface of the fireplace * ♦ 1 114238 8. In the latter position, the insert 2 'of the fireplace is capable of radiating towards the bark 1' through the openings between adjacent lamellae to heat the bark with radiant heat.

In the embodiment of Fig. 6, the lamellas 13 'are vertically bearing, whereby the force required to rotate the lamellas is very small. Reference numeral 15 'indicates an actuator for rotating the lamellas 13' at a desired angle. The actuator 15 'may be an actuator based on wax expansion, binary metal deformation, electrical temperature measurement and electrical control. For control, the temperature can be measured from the inlet or room or outside the building. In Fig. 7, reference numeral 16 'indicates a temperature sensor attached to the fireplace shell T. The actuator 15 'may be manually controlled or thermostatically controlled.

Figures 8 through 10 illustrate what a vertical blind can be fitted to a fireplace. In the Figures, reference numerals 15 to Figs 2-7 are used for like parts. Figures 8 to 10 show that each lamina 13 "of the vertical venetian blind 4" is supported by a double bearing 17 ". Reference numeral 18" indicates a push rod for adjusting the size of the openings between the lamellas 13 ". "partially open. By sliding the push rod 18" to the right (whereby the work-20 push rod in the image moves slightly downward), the openings between the lamellas 13 "are enlarged; and by sliding the push rod 18" left (thus pushing the rod smaller and even completely closed.

In the solutions described above, the plate-like elements acting as heat control means are heat-reflecting and heat-insulating material. Such material is, for example, a hollow aluminum grille containing air or some solid insulating material. Steel or other metal may be used instead of aluminum.

The invention has been described above by way of example and it is therefore to be noted that the details of the invention may vary in many respects. claims. Therefore, the number and exact location of the heat control means in the fireplace may vary. It is thus conceivable that some of the main surface of the fireplace, for example the front surface, is without heat control means.

The design of the heat control means may also vary. They may consist of a plurality of perforated plates placed over each other, one of which may be displaceable relative to the other, with the holes aligned or covered. In the aforesaid case, heat transfer from the interior of the fireplace to the casing is allowed; in the latter case, heat transfer is prevented. It is also conceivable that the temperature control means consist of a perforated plate with holes covered with bimetallic foils adapted to cover the holes when a certain temperature is exceeded, but which are adapted to pivot so that the holes open when a certain temperature drops. The latter adjustment does not allow for manual adjustment but is fully automatic, which is desirable in at least some applications. It is still conceivable that the heat control means comprise one or more roller blinds or blinds fitted between the interior of the fireplace and the cover. The technical design of roller blinds or blinds can be similar to that of roller blinds or blinds used in rooms. The choice of material must, of course, take into account sufficient temperature resistance. By adjusting the height of the roller curtain or blind, the heat transfer from the interior to the shell is affected.

> · I ·· • *

Claims (16)

A fireplace comprising an inner part (2, 2 ') with a fire hearth (3, 3'), and 'a housing (1, 1') arranged at a distance (S) from the inner part so that between the inner part and the housing there is a space (5, 5 '), characterized in that heat adjusting means (4, 4') are provided in the space (5, 5 ') between the inner part (2, 2') and the housing (1, 1 '), for to adjust the amount of radiant heat transmitted from the interior of the interior to the interior of the housing. Fireplace according to claim 1, characterized in that the heat adjusting means comprise a mechanical device (4, 4 ') arranged to effect adjustment of the amount of radiant heat by changing its position in said space (5, 5'). 3. Fireplace according to claim 1, characterized in that the heat adjusting means comprise a disk-like element which is slidable from a first position to a second position, the main surface of the element, where the disk-like element is in its first position, arranged to preventing radiant heat from being transferred from the surface of the inner portion to the inner surface of the housing, and the main surface of the element, where the disc-like element is in its second position, is in a position where it is prevented to impede said radiation heat transfer. Fireplace according to claim 3, characterized in that the housing 20 has an opening for at least partially removing the disk-like element from the space between the inner part and the housing, to displace the disk-like element into said second position. 5. Fireplace according to claim 1, characterized in that the heat adjusting means comprise a first disk-like element and a relative part thereof from a first position to a second position slidable second disk-like element, the first and the second disk-like element having a a row of heels, that the second member is arranged to cover the heel of the first sheet-like element where the second sheet-like element is in its first position, and that the heel of the second sheet-like element is opposite the heel of the first sheet-like element where the other the disk-like element is in its second position, to enable the transfer of radiant heat. 6. Fireplace according to claim 1, characterized in that the heat adjusting means (4, 4 ') comprise disc-like elements (13, 13'), and a pivot mechanism (6, 6 ') for placing the disc-like elements in the space (5). 5 ') between the inner part and the housing alternatively in a first position, the planes defined by the disk-like elements were substantially in the same direction as the plane defined by the inner part (2, 2') and thus prevent radiant heat from transferring. -from the surface of the inner member against the inner surface of the housing (1, 1 '), or a second position, the plane defined by the disk-like elements does not present said obstacle for transfer of radiant heat. Fireplace according to claim 6, characterized in that the heat adjusting means comprise a shutter curtain (4), whose slats (13) form said disc-like elements. 8. A fireplace according to claim 6, characterized in that the heat adjusting means comprise a slat curtain (4 ') with vertical slats which form said disc-like elements. 9. Fireplace according to any of claims 3-8, characterized in that the disc-like elements (13,13 ') are made of heat insulating and heat reflecting material. 10. Fireplace according to claim 1, characterized in that the heating! The adjusting means comprise a roller blind (4). 11. Fireplace according to claim 1, characterized in that the heat adjusting means extend from the lower part of the hearth (3) to the upper end of the hearth. 12. Fireplace according to claim 11, characterized in that the heat adjusting means extend from the fire hearth (3) to the fire cover. 13. Fireplace according to claim 1, characterized in that the heat adjusting means (4) are arranged in all the main walls of the fireplace. 14. A fireplace according to claim 2, characterized in that it comprises a control device (15 ') arranged to automatically change the position of the heating means in said space. 15. Fireplace according to claim 1, characterized in that the heat adjusting means comprise a glass surface. 16. Fireplace according to claim 1, characterized in that the heat adjusting means comprise a material whose characteristic of transmitting radiant heat is temperature dependent. • · · »