EP2221534B1 - Closed stove with air supply regulation - Google Patents

Description

The invention relates to a stove with a control of the air supply according to the preamble of claim 1 and the DE 103 24 634 A1 ,

From the DE 103 24 634 A It is known to provide a plurality of openings in an air supply channel, which open into separate air channels, wherein the openings can be released or closed by a lever which carries a shut-off device for each opening. The movement of the shut-off devices via cams against their weight. Because of the risk of contamination, the necessarily large tolerances and the high friction in the movement along the control surfaces, this device is susceptible to interference and unreliable.

From the DE 298 16 672 U1 It is known to provide in a heat insert for tiled stove or fireplace in the bottom area rotatable about a vertical axis regulator disk from which a pin projects upwards into a bifurcated slide. This slider is, barely guided and therefore prone to tilting, normal moves to its direction of extent, which at the beginning and at the end of the controlled system each almost the singular points are reached and the restoring forces theoretically go to infinity, practically into unusable.

From the US 4,407,265 It is known to provide in a lying in almost vertical plane front of a wood stove two coaxial control discs that can be rotated individually and so regulate the primary air and the secondary air.

Other regulations of the air supply in stoves are for example from the WO 1999/64789 A from which the EP 1 084 370 B emerged, known. Stoves, to which the invention relates in particular, have a grid on which rests the solid fuel and a substantially vertical viewing window, since the stove is not only like an oven to heat the environment, but also, like a fireplace, the To allow a view of the fire. In such stoves, a part of the combustion air, called primary air, supplied to the combustion chamber through the grate, another part of the combustion air, called secondary air, we fed to the combustion chamber above the lens and serves to accumulate smoke, the image of the burning solid could tarnish, to avoid and it is further supplied so-called nozzle air and that in an area of the rear wall of the combustion chamber above the grate. The nozzle air also essentially serves to create an optically satisfactory image of the firing process.

It is now necessary to create a fire of the desired intensity, the production of a satisfactory visual image of the fire and the greatest possible reduction of emissions, the amounts of each supplied air, it is always understood the amounts per unit time to regulate.

• die Fig. 1 einen erfindungsgemäßen Kaminofen in Frontansicht,
• die Fig. 2 den Ofen der Fig. 1 im Schnitt entlang der Linie II-II der Fig. 1,
• die Fig. 3 einen Schnitt entlang der Linie III-III der Fig. 1,
• die Fig. 4 einen Schnitt entlang der Linie IV-IV der Fig. 1 und
• die Fig. 5 einen Überblick über die Verfahrensschritte und Verfahrenszustände.

According to the invention, this is done as a function of the temperature of the exhaust gas and its temporal change in the described below, the characterizing part of claim 1 corresponding device. the description describing first a stove according to the invention and then the method. The dependent claim defines an advantageous embodiment. The invention will be explained in more detail below with reference to the drawing. It shows

• the Fig. 1 a stove according to the invention in front view,
• the Fig. 2 the oven the Fig. 1 in section along the line II-II of Fig. 1 .
• the Fig. 3 a section along the line III-III of Fig. 1 .
• the Fig. 4 a section along the line IV-IV of Fig. 1 and
• the Fig. 5 an overview of the process steps and process states.

How out Fig. 1 and 2 can be seen, has a designated in its entirety by 1 inventive stove a central air connection 2, with which the combustion air passes into a distribution chamber 3. The bottom of the distribution chamber 3 has a substantially circular recess which is covered by a regulator disk 4. The regulator disk 4 has various recesses or openings 11, over which further details will be made below.

Below the distribution chamber 3 there are three channels: channel 5 for the nozzle air, channel 6 for the secondary air and channel 7 for the primary air. Partitions 8 are provided between the channels, these also seal off the individual channels against the control disk 4 to the necessary extent, so that, depending on their angular position, different sized surface portions of the openings 11 of the control disk connect to each of the individual channels 5, 6, 7 manufactures. In this way it is possible to distribute the distribution of the total incoming combustion air within wide limits to the primary air channel 7, the secondary air channel 6 and the nozzle air channel 5.

The forwarding of the three air streams by means of separate channels is carried out in the usual way and requires no further explanation, as well as the respective entry points of these channels in the combustion chamber. It is also significant that the control motor 12 is preferably arranged in the central channel, in the embodiment shown thus in the nozzle air channel 5 for the implementation of the rotational movement of the control disk 4 and either attached to one of the two separations 8 interconnecting piece of sheet metal or directly to the two separations is. It can also be provided that the motor 12 is arranged in a manner fixed against rotation by the shape of its housing, so to speak, in the nozzle air channel 5, so that during its operation the rotation of the regulator disk 4 takes place only by the reaction torque. This has the advantage that thermally induced change of the geometry can not lead to a fixing of the control disk 4, since the drive motor 12 can join in the corresponding position changes. At the Fig. 2 designated 9, thus the flue pipe connecting to the chimney (not shown), a temperature sensor 10 is arranged which measures the temperature of the flue gas leaving the furnace.

On the one hand, it is possible to empirically determine the relationship and in the form of a table or graphically, based on the experiments that all stoves must go through before their admission for sale. set electronically. It is also possible, due to the known laws of thermodynamics with knowledge of the geometry of the furnace and in knowledge of the materials used to make a corresponding recalculation. It should be noted that it is only partially possible to transfer such relationships from one stove to another, without taking into account the differences in design, size, power, etc., accordingly.

The control device consists essentially of the following parts: A temperature sensor 10, which is positioned on the flue pipe socket 9 and with which the exhaust gas temperature is measured; a controller housing with the associated controller disk 4, are arranged in the geometrically different openings 11; an electronics unit and a drive motor 12 which moves the regulator disk 4, the electronic unit is integrated in a regulator box.

In the controller housing are the three separate air channels for the primary air 7, secondary air 6 and nozzle air 5. Based on the calculated or determined by the above-mentioned conversion table / graph combustion chamber temperature, the controller disk 4 is brought by means of the drive motor 12 in the respective predetermined position, so that according to the heating power, the combustion air is supplied via the respective air channels to the combustion chamber 14. Depending on the position of the regulator disk, the combustion air can flow into the combustion chamber via one, two or simultaneously via all three air ducts in predetermined proportions.

In principle, it is thus so that the supplied below the grate through a central port external combustion air enters a distribution chamber, which is closed at one of its horizontal end faces, preferably the bottom side, with a rotatable regulator disk having openings or cuts through which the Air from the distribution chamber in one of three arranged on the other side of the regulator disc channels passes.

By choosing the appropriate angular position of the controller disk and thus the suitably shaped and arranged perforations or recesses, it is possible to adapt the three required air flows in a wide range of the current operating state.

Description of the scheme:

In Fig. 4 the names of the individual control or operating states are listed in oval fields, whereby instead of "first" etc., "1" etc. is indicated briefly. The arrows represent the transitions from one state to the other, in the course of the arrows the conditions that cause the control electronics to switch from one state to the other are indicated.

The values given are purely illustrative, which are not symbolic, but are only of the order of magnitude and, above all, have to be adapted to the individual, real stove.

The exhaust gas temperature or flue gas temperature T _RG is measured at the flue pipe socket 9 with a commercially available temperature sensor 10 and a mathematical model, which is stored on the electronic board or an EPROM, from the measured exhaust gas temperature, the furnace temperature, hereinafter often simply called temperature, certainly. The combustion chamber temperature T _{FR determined in this way} and the gradient with which the combustion chamber temperature increases or decreases over time (T _FR ') are the controlled variables which are subsequently used for regulation and ultimately lead to the movement of the regulator disk 4.

The control concept is based on the fact that the amount of combustion air supplied and its distribution to primary air, secondary air and nozzle air are optimally adapted to the different phases of the burning cycle of a wood-burning stove. For this purpose, the controller disk 4 is used. There is a further supply air opening 13 for the secondary air, which is unregulated and thus ensures a minimum flow of secondary air, whereby contamination of the window is prevented.

The control uses the one or the other way "certain" furnace temperature T _FR and its time derivative T _FR 'as a controlled variable. On the basis of the respective value for the combustion chamber temperature T _FR and its time derivative T _FR ', the control recognizes in which phase of operation the furnace is or when the furnace changes from one combustion phase to another combustion phase, and the air distribution disk is switched by means of the engine 12 with gearbox in the operating state corresponding position.

In this case, a distinction is made between the idle state, two heat-up phases, one burning-on phase, one main burning phase and two different burn-out phases. For each of these Abbrandphasen a position of the air distribution disc is defined in which, in this operating state optimized amounts of primary air, disc air and nozzle air are supplied.

Example procedure for heating the oven:

The oven is heated by the user, starting at rest, by means of (for example) three times fuel deposition, which takes place at a time interval from each other. In idle state, the controller disk is in the first controller position. The control electronics detect the increase in temperature and the rate of increase. If this is higher than the start change T _{FR, Start} 'corresponds (for example, 3 ° C / min), it recognizes the beginning of a heating process, namely the first heating phase, but leaves the controller disk 4 still in the first control position.

1. A) Wenn die errechnete Feuerraumtemperatur TFR für einen längeren Zeitraum als eine vorbestimmte Endzeit τ_Ende (beispielsweise 300sec) niedriger ist als eine vorbestimmte Endtemperatur T_Ende (beispielsweise 200°C), beispielsweise, weil nicht ausreichend Brennmaterial im Ofen ist, so erkennt die Regelelektronik das Ende des Brennvorganges und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung, der Ruhezustand ist erreicht, der Zyklus ist beendet.
2. B) Wenn die errechnete Feuerraumtemperatur T_FR höher wird, als die vorgegebene Anheiztemperatur T_Anheiz (beispielsweise 700°C), gegebenenfalls unter der Maßgabe, dass die Überschreitung über eine vorbestimmte Zeit τ_Anheiz (beispielsweise 300sec) erfolgen muss (ausreichende Brennstoffmenge), so verstellt die Regelelektronik die Reglerscheibe 4 von der ersten Reglerstellung in die zweite Reglerstellung, die zweite Anheizphase ist erreicht.

Then there are two possibilities:

1. A) If the calculated firing space temperature TFR is lower than a predetermined _end temperature T _end (eg, 200 ° C) for a period longer than a predetermined end time τ _end (eg, 300 ° C), for example, because there is insufficient fuel in the furnace, the control electronics will detect the end of the burning process and puts the controller disk 4 back into the first controller position, the idle state is reached, the cycle is ended.
2. B) If the calculated combustion chamber temperature T _{FR is} higher than the predetermined heating temperature T _Anheiz (700 ° C, for example), provided that the excess over a predetermined time τ _{Anheiz must} (for example, 300sec) (sufficient amount of fuel), so the control electronics adjusts the control disk 4 from the first control position to the second control position, the second heating phase is reached.

1. A) Wenn die Feuerraumtemperatur T_FR für einen längeren Zeitraum als eine vorbestimmte Endzeit τ_Ende (beispielsweise 300sec) niedriger ist als eine vorbestimmte Endtemperatur T_Ende (beispielsweise 200°C) (Brennstoffende), so erkennt die Regelelektronik das Ende des Brennvorganges und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung, der Ruhezustand ist erreicht, der Zyklus ist beendet.
2. B) Wenn die Änderung (Verringerung) der Feuerraumtemperatur T_FR' kleiner (= schneller) ist, als es einer ersten Übergangsgeschwindigkeit T_FR41a' (beispielsweise -7,5°C/sec) entspricht (Öffnen der Brennraumtür zum Nachlegen), so erkennt die Regelelektronik den die Notwendigkeit des Übergangs des Brennvorganges in die sogenannte Anbrennphase und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung.
3. C) Wenn die Änderung (Verringerung) der Feuerraumtemperatur T_FR' kleiner (= schneller) ist, als es einer zweiten Übergangsgeschwindigkeit T_FR41b' (beispielsweise -5,0°C/sec) entspricht, dies aber bei einer Temperatur, die unter einer sogenannten ersten Übergangstemperatur T_FR41 liegt, so erkennt die Regelelektronik ebenfalls den Übergang des Brennvorganges in die sogenannte Anbrennphase und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung.

Starting from the second heating phase, there are three possibilities, depending on the further development of the furnace temperature T _FR :

1. A) If the firing chamber temperature T _FR for a period longer than a predetermined end time τ _end (for example, 300sec) is lower than a predetermined _end temperature T _end (for example, 200 ° C) (fuel end), then recognizes the control electronics the end of the burning process and puts the controller disk 4 back into the first controller position, the idle state is reached, the cycle is ended.
2. B) If the change (decrease) in the combustion chamber temperature T _FR 'is smaller (= faster) than corresponds to a first transition _velocity T _FR41a ' (for example -7.5 ° C / sec) (opening of the combustion chamber _{door for replenishment} ), then recognizes the control electronics the need for the transition of the firing process in the so-called Anbrennphase and provides the regulator plate 4 back to the first regulator position.
3. C) If the change (decrease) in the firing chamber temperature T _FR 'is smaller (= faster) than it corresponds to a second transition _velocity T _FR41b ' (for example -5.0 ° C / sec), but at a temperature below that so-called first transition temperature T _FR41 , so the control electronics also detects the transition of the firing process in the so-called Anbrennphase and puts the controller disk 4 back into the first controller position.

1. A) Wenn die Feuerraumtemperatur T_FR niedriger ist als eine vorbestimmte Endtemperatur T_Ende (beispielsweise 200°C), gegebenenfalls erst nach einem längeren Zeitraum als eine vorbestimmte Endzeit τ_Ende (beispielsweise 300sec) (Brennstoffende), so erkennt die Regelelektronik das Ende des Brennvorganges, belässt die Reglerscheibe 4 in der ersten Reglerstellung, der Ruhezustand ist erreicht, der Zyklus ist beendet.
2. B) Wenn die Feuerraumtemperatur T_FR über eine vorbestimmte Hauptbrenntemperatur T_Phase12 (beispielsweise 680°C) steigt, so erkennt die Regelelektronik den Übergang des Brennvorganges in die sogenannte Hauptbrennphase und stellt die Reglerscheibe 4 wieder (nach der zweiten Anheizphase) in die zweite Reglerstellung.

After reaching the firing phase, there are two options depending on the further course of the firing space temperature T _FR :

1. A) If the firing chamber temperature T _{FR is} lower than a predetermined _end temperature T _end (for example 200 ° C), possibly only after a longer period than a predetermined end time τ _end (for example 300sec) (fuel end), the control electronics detects the end of the firing process , leaves the controller disk 4 in the first control position, the idle state is reached, the cycle is completed.
2. B) When the firing chamber _temperature T _FR rises above a predetermined main _{firing temperature} T _{phase 12} (for example 680 ° C.), the control electronics detects the transition of the firing process to the so-called main firing phase and sets the regulator disk 4 (after the second firing phase) into the second regulator position.

After reaching the main combustion phase, this is maintained until the undershooting of a burnout _temperature T _FR23 and / or a cooling rate below (= faster) a predetermined _{Ausbrandtemperaturabsenkung} T _FR23 '(for example, -7.5 ° C / sec, corresponds to the refueling) becomes. Thus, it is recognized by the control electronics that the first burn-out phase is reached, and the control disk 4 is brought into its third control position.

1. A) Wenn die Änderung (Verringerung) der Feuerraumtemperatur T_FR' kleiner (= schneller) ist, als es der ersten Übergangsgeschwindigkeit T_FR41a' (beispielsweise -7,5°C/sec, Nachlegen) entspricht, so erkennt die Regelelektronik den Übergang des Brennvorganges in die sogenannte Anbrennphase und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung.
2. B) Wenn die Änderung (Verringerung) der Feuerraumtemperatur T_FR' kleiner (= schneller) ist, als es der zweiten Übergangsgeschwindigkeit T_FR41b' (beispielsweise -5,0°C/sec) entspricht, dies aber bei einer Temperatur, die unter der sogenannten ersten Übergangstemperatur T_FR41 liegt, so erkennt die Regelelektronik ebenfalls den Übergang des Brennvorganges in die sogenannte Anbrennphase und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung.
3. C) In allen anderen Fällen wird von der Regelelektronik nach einer Wartezeit (beispielsweise zwei Minuten) der Übergang in die zweite Ausbrandphase erkannt und die Reglerscheibe 4 in ihre vierte Reglerstellung gebracht.

After reaching the first burnout phase, there are three options:

1. A) If the change (decrease) in the firing chamber temperature T _FR 'is smaller (= faster) than corresponds to the first transition _velocity T _FR41a ' (for example -7.5 ° C / sec, refueling), then the control electronics detects the transition of the Burning process in the so-called Anbrennphase and sets the controller disk 4 back to the first controller position.
2. B) If the change (decrease) in the firing chamber temperature T _FR 'is smaller (= faster) than it corresponds to the second transition _velocity T _FR41b ' (for example -5.0 ° C / sec), but at a temperature _lower than that so-called first transition temperature T _FR41 , so the control electronics also detects the transition of the firing process in the so-called Anbrennphase and puts the controller disk 4 back into the first controller position.
3. C) In all other cases, the control electronics after a waiting time (for example, two minutes), the transition to the second burn-out detected and brought the controller disk 4 in its fourth control position.

1. A) Wenn die Änderung (Verringerung) der Feuerraumtemperatur T_FR' kleiner (= schneller) ist, als es der ersten Übergangsgeschwindigkeit T_FR41a' (beispielsweise -7,5°C/sec, Nachlegen) entspricht, so erkennt die Regelelektronik den Übergang des Brennvorganges in die sogenannte Anbrennphase und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung.
2. B) Wenn die Änderung (Verringerung) der Feuerraumtemperatur T_FR' kleiner (= schneller) ist, als es der zweiten Übergangsgeschwindigkeit T_FR41b' (beispielsweise -5,0°C/sec) entspricht, dies aber bei einer Temperatur, die unter der sogenannten ersten Übergangstemperatur T_FR41 liegt, so erkennt die Regelelektronik ebenfalls den Übergang des Brennvorganges in die sogenannte Anbrennphase und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung.
3. C) Wenn die errechnete Feuerraumtemperatur T_FR niedriger ist als eine vorbestimmte Endtemperatur T_Ende (beispielsweise 200°C) (beispielsweise, weil nicht mehr ausreichend Brennmaterial im Ofen ist), so erkennt die Regelelektronik das Ende des Brennvorganges und stellt die Reglerscheibe 4 wieder in die erste Reglerstellung, der Ruhezustand ist erreicht, der Zyklus ist beendet.

After reaching the second burn-out phase, there are three possibilities:

1. A) If the change (decrease) in the firing chamber temperature T _FR 'is smaller (= faster) than corresponds to the first transition _velocity T _FR41a ' (for example -7.5 ° C / sec, refueling), then the control electronics detects the transition of the Burning process in the so-called Anbrennphase and sets the controller disk 4 back to the first controller position.
2. B) If the change (decrease) in the firing chamber temperature T _FR 'is smaller (= faster) than it corresponds to the second transition _velocity T _FR41b ' (for example -5.0 ° C / sec), but at a temperature _lower than that so-called first transition temperature T _FR41 , so the control electronics also detects the transition of the firing process in the so-called Anbrennphase and puts the controller disk 4 back into the first controller position.
3. C) When the calculated combustion chamber temperature T _{FR is} lower than a predetermined _end temperature T _end (for example, 200 ° C) (for example, because not more sufficient fuel is in the oven), so the control electronics detects the end of the burning process and sets the regulator disc 4 back to the first regulator position, the idle state is reached, the cycle is completed.

In the individual regulator positions, for example, the following ratios of the sizes of the individual openings (in mm ² ) are present, the secondary air opening 13 having a size of 325 mm ² always being additionally open: controller position phases primary air secondary air jet air First Rest, 1. heating, burning. 460 1570 450 Second 2. heating up, main burn. 0 2420 2570 third 1. burnout. 0 1750 130 Fourth 2. burnout. 90 1650 0

This distribution of the air, in particular the primary air, which flows from the bottom through the grate directly into the fuel causes, from the idle state (first regulator position) away and in the first heating phase (first regulator position) a quick start and a rapid burning of the launched Fuel is achieved, and that during the second burn-out phase (fourth regulator position) any fuel residues quickly burn on and burn off, which may lead (refueling) to (re) firing the fire and back into the burning phase; but mostly to lower the temperature and thus in the resting state.

During the second heating phase (second control position) a stable, but not excessively flaming fire is achieved by blocking the primary air and the total strong air supply, which causes a good and lasting heating performance. If the temperature drops, the transition to the firing phase (first regulator position) with its primary air fraction keeps the fire going.

When the predetermined main _{firing temperature} T _{phase 12 is exceeded} during the firing phase (first regulator position), which can essentially be done by the primary air fraction, the transition to the main firing phase (second regulator position) takes place in which no primary air is supplied, which leads to calm.

When no new fuel is applied, the temperature eventually drops, the first burnout phase without primary air and reduced total air supply is achieved, followed by the second burnout phase with some primary air supply already described above, either to end or to ignite the fire.

About the three phase transitions in determining a rapid drop in temperature is still to be stated that such a rapid drop in temperature can be effected only by opening the door when refueling, which causes each time the transition to the Anbrennphase with high primary air content. The slower drop in temperature is due to the end or the approaching end of the combustion process due to fuel shortage and leads to a corresponding reaction of the scheme.

The openings shown in the drawing and the parameters, temperatures and timings set in the electronic control are adapted to the heating power, the geometry of the combustion chamber and the combustion chamber lining (fireclay) of the fireplace used for the description. With a changed combustion chamber geometry or with a change in the heating power, with a change in the combustion chamber lining etc., the openings and the positions of the regulator disk or the parameters, temperatures and time sequences must be changed or adjusted.

By the regulation according to the invention it is achieved, both the emissions of the heating gas (CO content, dust content, OGC emissions [organic carbon, because of the health hazard a significant value for the burden on the environment, can be reduced by high combustion temperatures, especially at the beginning of the firing process ]) to greatly reduce, as well as to increase the efficiency of the furnace considerably.

The adjusting motor shown is preferably equipped with a slip clutch, thereby the regulator disc, if, for example, the power fails or the engine breaks down, can also be adjusted by hand. Thus, emergency operation of the stove is possible even in exceptional situations.

Of course, further phases can be provided with further positions of the regulator disk, it is also not necessary for the method to use a regulator disk, although the regulation becomes very reliable and independent of the external conditions because of the regulation from a common distribution box. It is also possible for the method to individually control individual flaps or slides, although it also entails a greater outlay on equipment. For the stove, in turn, the use of the regulator disc is of great value, even if it is a different process is realized.

It is also possible to dispense with one of the two or both heating phases, thereby extending the time to reach a stable fire, which is associated with an increase in pollutant emissions. In particular, in countries or regions with low environmental awareness, this is a possibility of simplification, albeit not to be endorsed.

Finally, the specified times, temperatures and temperature gradients are to be understood as indicative only and to be adapted on a case-by-case basis.

Claims (2)

1. Stove having a combustion chamber having a grate, a back wall, side walls, a front door and a covering plate, said combustion chamber having a distributor chamber (3) having a wall which separates it from three channels that are separate from one another, one for the primary air (7), one for the secondary air (6) and one for the nozzle air (5), characterised in that the wall has a circular opening covering all channels which is capped by a rotatable regulating disc (4), the regulating disc (4) has recesses or openings (11) through which connections of variable cross-section between the distributor chamber and the individual channels can be produced, and an opening (13) of fixed cross-section between the distributor chamber (3) and the secondary air channel (6) is provided.
2. Stove according to claim 1, characterised in that the regulating disc (4) is rotated by a motor (12).

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