EP3255343A1

EP3255343A1 - Module for discharging flue gases

Info

Publication number: EP3255343A1
Application number: EP17174774.4A
Authority: EP
Inventors: Stefan René Jeanne Brouwers; Elwin Gerardus Theodorus Driesen
Original assignee: VFM Cvba
Current assignee: VFM Cvba
Priority date: 2016-06-09
Filing date: 2017-06-07
Publication date: 2017-12-13
Also published as: BE1024278B1; BE1024278A1

Abstract

Module for discharging flue gases, comprising a frame with a flue gas duct extending through the frame, wherein the flue gas duct is delimited by a flue gas duct wall and wherein a throttle valve (14) is provided in the flue gas duct, wherein a control element (21) for opening and closing the throttle valve further extends through the flue gas duct wall between the throttle valve and an actuator (22), wherein the frame further comprises a mounting wall (23) for mounting of the actuator, and wherein the mounting wall is provided at a distance from the flue gas duct wall in order to prevent direct heat transfer from the flue gas duct wall to the actuator.

Description

The invention relates to a module for discharging flue gases for a stove.
Stoves are generally known heating means for homes. Where in the past a stove was usually provided as multi-burner, optionally optimized for burning wood and/or coal, there is a trend in recent years to provide more pellet stoves or gas stoves which are specifically provided to burn respectively pellets or gas. The advantage of pellets or gas as fuel is that the supply of the fuel can be controlled mechanically in automatic manner so that the energy output of the stove can be controlled thereby.
A stove is defined as a heating device wherein the primary object is direct heating of the immediate area around the stove. A stove is typically distinguished from other heating means in that it is a secondary object of a stove to achieve an aesthetically appealing combustion in the stove. The combustion chamber is for this purpose formed as a casing in which the combustion can take place, and a part of the casing is formed by a transparent material, for instance glass. The transparent material here has dimensions which are chosen to simultaneously allow several people in the area surrounding the stove to see the flames created during the combustion process in the combustion chamber.
In order to optimize the combustion in the stove a good ratio of fuel and combustion air is essential. Different techniques for controlling the combustion air flow have been known for a long time. The heat of the flue gases creates a so-called draught in the chimney, which draws combustion air through the combustion chamber. This airflow can then be influenced or controlled by placing a valve at the inlet of the combustion chamber and/or at the outlet of the combustion chamber for the purpose of throttling the duct through which the combustion air flows. The natural draught of the chimney can be enhanced by placing a fan. This fan is typically placed upstream of the combustion chamber in the airflow duct in order to push the air through the combustion chamber in a controlled manner.
It is an object of the invention to improve the operation of a stove with active combustion air flow controllers and to increase the safety of such a stove.
The invention provides for this purpose a module for discharging flue gases, comprising a frame with a flue gas duct extending through the frame, wherein the flue gas duct is delimited by a flue gas duct wall and wherein a throttle valve is provided in the flue gas duct, wherein a control element for opening and closing the throttle valve further extends through the flue gas duct wall between the throttle valve and an actuator, wherein the frame further comprises a mounting wall for mounting of the actuator, and wherein the mounting wall is provided at a distance from the flue gas duct wall in order to prevent direct heat transfer from the flue gas duct wall to the actuator.
The module according to the invention is optimized for discharging flue gases, and is thereby typically placed on the outlet side of the combustion chamber of the stove. The placing of a flue gas extractor in a discharge for flue gases is made difficult in practice by the temperature of the flue gases. The temperature of the flue gases will typically heat the discharge for flue gases, and thereby also heat the flue gas extractor, so that this latter must be able to operate properly at high temperatures. However, because in the invention a mounting wall is provided on which the actuator is mounted, and wherein the mounting wall is provided at a distance from the flue gas duct wall, it is possible to prevent the heat of the flue gases which flow in the flue gas duct from being transferred directly to the actuator. Due to this construction, the actuator can be screened from the heat of the flue gases and the module can function reliably.
The process of combustion in the combustion chamber is largely dependent on the ratio of fuel and air in the combustion chamber. The module according to the invention can determine the quantity of air which flows through the combustion chamber, whereby the module ca control the combustion via the actuator and throttle valve. An efficient operation of the stove can be achieved hereby.
The invention further has an unexpectedly positive effect. Because the module is optimized for placing in the discharge for flue gases, the module will draw air through the combustion chamber. The result hereof is that the combustion chamber of the stove is subjected to underpressure. Because a combustion chamber and the elements mounted thereon, such as a discharge for flue gases and feed for combustion air, can never be manufactured so as to be 100% airtight, it is an advantage to have an underpressure in the stove because the underpressure ensures that possible soot or CO or other harmful byproducts of a combustion will not leak out of the stove, or hardly so. This in contrast to stoves which actively blow combustion air to the combustion chamber, which is thereby at overpressure, and which do tend to allow soot, CO₂ and other harmful combustion products to leak to the area surrounding the stove. This effect of leakage from the combustion chamber is enhanced in practice by modern airtight insulated houses wherein the air is refreshed by means of a balanced ventilation system and wherein in accordance with recent building regulations the space in the house may be subject to slight underpressure.
The module is preferably formed such that the flue gas duct wall sub-divides the frame into a first part which is provided to enclose the flue gases and a second part, wherein the frame has ventilation openings in the second part. The actuator is placed in the second part, which has ventilation openings, and on a mounting wall which is provided at a distance from the flue gas duct wall. Heat which still finds its way to the mounting wall will hereby not be given the opportunity to heat the mounting wall appreciably, because the second part of the frame is ventilated by means of the ventilation openings.
The throttle valve is preferably formed by mounting a plate movably relative to a fixedly positioned opening in the flue gas duct, such that the plate is movable between a first position in which the plate substantially closes the opening and a second position in which the plate impedes an airflow through the opening to minimal extent. Tests have shown that constructing a throttle valve in such a manner is reliable and achieves a correct operation at low and at high temperatures. Controlling of the throttling and the opening and closing of the opening by means of the movable plate can further be mechanically controlled and realized in simple manner.
The plate is preferably fixedly connected to a control element which is movable by the actuator via an intermediate element so as to move the plate between the first position and the second position. The control element is here preferably further positioned eccentrically relative to the rotation axis, and the intermediate element is formed as a connecting rod. The fixedly positioned opening preferably extends over only a part of the partition. On one side of the partition the flue gas duct is here preferably provided with a section smaller than the section of the partition. The partition thereby forms at least partially a segment of the flue gas duct wall. This allows the plate to be placed on the partition with a shaft extending through the partition from a position inside the flue gas duct to a position outside the flue gas duct. The plate is then positioned on the side of the partition where the flue gas duct has a greater section, while the control element extends to, and the eccentric part of the control element in particular is situated at a position outside, the flue gas duct. Such a construction can be realized in simple manner and produces a reliable operation. It is further easy to control the movable plate in this way by means of the actuator. By further providing a connecting rod the distance between the actuator and the plate with the control element can be increased further, so that heat transfer from plate to actuator is further reduced.
An insulating panel is preferably provided between the flue gas duct wall and the mounting wall. The insulating panel further reduces the heat transfer between the flue gas duct wall and the mounting plate. The insulating panel allows the distance between the mounting plate and the flue gas duct wall to be small, while still achieving a good thermal separation.
The mounting wall and the flue gas duct wall preferably have an opening which in mounted state is aligned such that a lambda probe can be placed through the opening and can be mounted against the mounting wall. The lambda probe serves to measure the quantity of oxygen in the flue gases, and will therefore need to extend at least partially into the flue gas duct. By mounting the lambda probe against the mounting plate, which is at least partially thermally separated from the flue gas duct wall, the temperature of the lambda probe can be optimized.
The actuator is preferably formed as a servomotor, wherein a lever arm is provided on the rotation shaft of the servomotor, which lever arm has an eccentric connection for connecting to the control element. The control element can here be connected via the connecting rod to the eccentric connection of the servomotor. It is possible to achieve a precise actuation of the plate via the servomotor, so that the throttle valve can be precisely controlled.
The module is preferably operatively connected to a stove with a combustion chamber and smoke discharge, and the module is preferably mounted at a distance of at least 1 metre, preferably at least 2 metres, more preferably at least 3 metres and at a distance of a maximum of 10 metres, preferably a maximum of 8 metres, more preferably a maximum of 6 metres from the combustion chamber of the stove. Tests have shown that placing the module at such a distance from the combustion chamber is optimal on the one hand for controlling the airflow and on the other hand for controlling the temperatures in the module.
The invention further relates to a stove with a combustion chamber and active combustion air flow controller which is operatively connected to the stove for the purpose of controlling an airflow through the combustion chamber, wherein the active combustion air flow controller is formed by a module according to the above described invention.
The invention will now be further described with reference to an exemplary embodiment shown in the drawing.
In the drawing:

figure 1 shows a stove with a construction according to a preferred embodiment of the invention;
figure 2 shows a first section of a module according to a preferred embodiment of the invention; and
figure 3 shows a second section of a module according to a further preferred embodiment of the invention.

The same or similar elements are designated in the drawing with the same reference numerals.
Figure 1 shows a stove 1 which is connected according to a preferred embodiment of the invention. A stove has already been defined above as a heating device wherein the primary object is direct heating of the immediate area around the stove, and wherein the secondary object is to achieve an aesthetically appealing combustion in the stove. A stove can further be defined as a fireplace, this being an open fireplace or closed fireplace, with an active combustion air flow controller. When the combustion air is actively controlled in a fireplace, as in the context of the present invention, the terms fireplace and stove can therefore be used synonymously with each other. Tertiary airflows can here further be controlled at the stove, which do not run through the combustion chamber but do run around the combustion chamber in order to thus extract heat from the combustion chamber, which tertiary air can then be guided via a network of ducts to other spaces so that spaces which are not deemed to be the immediate surrounding area can also be heated by the stove.
Stove 1 comprises a combustion chamber 2 which is formed as a casing for the fire when fuel is combusted, and wherein at least a part of the casing is formed by a transparent material 3, for instance glass. Glass 3 has a surface area which is preferably greater than 0.04 m², more preferably at least 0.1 m² and most preferably greater than 0.2 m². The glass can extend in one or more sides of casing 2 so that traditional built-in stoves as well as corner stoves and/or see-through stoves can be formed. During combustion of fuel the fire 4 present inside the casing of combustion chamber 2 is visible to several users at the same time through transparent material 3.
Stove 1 is provided with an active combustion air flow controller. Stove 1 is provided for this purpose with a feed for combustion air 5 and a discharge for flue gases 6. The combustion air feed 5 and flue gas discharge 6 can be formed coaxially (not shown) or, as illustrated in figure 1, be formed and placed separately of each other. The combustion air feed 5 preferably extends into a space other than the space in which combustion chamber 2 is situated. An airflow, illustrated with arrow 7, can be supplied via combustion air feed 5 to the combustion chamber. This air, which serves for the combustion, is also referred to as combustion air 7.
The flue gas discharge 6 preferably extends to a chimney. Flue gases can be discharged via flue gas discharge 6, which is illustrated in figure 1 with arrow 8. Flue gases 8 are guided via flue gas discharge 6 into the chimney, where they can flow out via the chimney, which is illustrated in figure 1 with arrow 9.
Stove 1 is preferably provided with an automatic fuel supply for supplying fuel to the combustion chamber, which is illustrated in figure 1 with arrow 10. In figure 1 a reservoir 11 in which fuel, for instance pellets, is stored is provided at combustion chamber 2, wherein a duct extends from reservoir 11 to the combustion chamber. Providing a controller (not shown) in the duct allows fuel to be carried from reservoir 11 to combustion chamber 2 in a controlled manner. It will be apparent that this is only one example of an embodiment for supplying fuel. A gas conduit to combustion chamber 2 can alternatively be placed, wherein a valve is provided in the gas conduit in order to allow gas to enter combustion chamber 2 in a controlled manner. These are only two examples of automatic fuel supply systems, and the skilled person will be easily able to apply alternatives and/or equivalent automatic fuel supply systems in the present invention.
Stove 1 further comprises a module 12 for actively controlling the airflow which flows through combustion chamber 2. In the figure module 12 is placed in the flue gas discharge 6. Module 12 can alternatively be placed in combustion air feed 5. Module 12 comprises an air pump for actively controlling an airflow, which air pump is formed by a combination of a fan 13 and a throttle valve 14 in figure 1. The skilled person will here also understand that alternative active air pumps can be applied as replacement for the combination of fan 13 and throttle valve 14. Tests have shown that a combination of fan 13 and throttle valve 14 produces good and reliable results and is therefore a preferred air pump. Module 12 preferably further comprises a lambda probe 15 for measuring the oxygen content in the flue gases.
The different components of stove 1, such as the combustion chamber 2 with automatic fuel supply 10 and the module 12 with fan 13, throttle valve 14 and lambda probe 15, are operatively connected to a controller 17. The operative connection is illustrated in figure 1 with reference numeral 16. The operative connection can in practice be formed via cabling, wirelessly, or via a combination thereof.
Controller 17 comprises a processor with one or more inputs for reading sensors and/or states of components of stove 1. It will be apparent here that sensors can be formed by pressure sensors, temperature sensors, the lambda sensor 15, position sensors, for instance for measuring a position of a door or valve on the combustion chamber, the reservoir 11 or the module 12. The skilled person will understand that different sensors for measuring different states or properties can be placed in the stove, and that the list provided above is not limitative. States of components can be understood to mean the rotation speed of fan 13, the position of throttle valve 14, the filling level of reservoir 11, the supply speed 10 of the fuel. The skilled person will understand that different states and different properties of stove 1 can be read and that the summary provided above is not limitative. The processor is provided for processing the inputs and for controlling outputs.
Controller 17 preferably further comprises a plurality of outputs which are controlled by the processor for transmitting signals or instructions to different components of stove 1. It is preferably possible via the output to control fuel supply 10, to control fan 13 and to control throttle valve 14. Controller 17 is shown as a separate module in figure 1. The skilled person will however understand that controller 17 can also be integrated into one of the other components of the stove, for instance into combustion chamber 2 or into module 12. Controller 17 can also be distributed over different components, wherein different functions, inputs, outputs and/or computations can be executed at different locations in stove 1.
Controller 17 further comprises a user interface 18. A user interface 18 is shown as a remote control in figure 1. The user interface can also be formed as an application on an electronic end user device, for instance an application on a smart phone, so that controller 17 can be controlled by the user via the user interface 18. Instructions can be sent via user interface 18 to controller 17, which then further controls stove 1 on the basis of the instructions, taking into consideration the inputs, so as to guarantee an optimal, safe and correct operation of stove 1.
Figure 2 shows a module 12 for discharging flue gases for a stove according to a preferred embodiment of the invention. Figure 2 shows here a module 12 wherein flue gases flow from the stove into module 12 on a left-hand side of the figure, which is designated with reference numeral 8. On the right-hand side of module 12 the flue gases leave the module in the direction of the chimney, which is designated with reference numeral 9. The inlet and the outlet of module 12, between which flue gas duct 6 extends, are thereby shown. Further situated between this inlet and this outlet, in flue gas duct 6, are fan 13 and throttle valve 14. The flue gas duct in module 12 is delimited by a flue gas duct wall 19. Because the flue gases come into direct contact with flue gas duct wall 19, the temperature of flue gas duct wall 19 will be greatly affected by the temperature of the flue gases. The flue gas duct wall will therefore also become warm or hot in practice.
An opening 20 is provided in the flue gas duct wall so that a lambda probe 15 can extend through flue gas duct wall 19 and into the flue gas duct. A lambda probe 15 typically has a base body and a sensor part extending from this base body. Opening 20 allows the base body to be mounted outside flue gas duct 6, while the sensor extends through the flue gas duct wall 19 and into the flue gas duct 6. The base body of lambda probe 15 can be mounted on mounting wall 23, which will be discussed in more detail hereinbelow. This mounting of lambda probe 15 on mounting wall 23 is designated in the figure with reference numeral 36.
Throttle valve 14 is preferably formed by means of a movable plate 28 which is situated in flue gas duct 6 and which is mounted movably, preferably rotatably, via a control element 21, 32, which is shown in the embodiment of figure 2 as a rotation shaft 21 with an eccentric part 32. In the figure the eccentric part 32 of the control element extends to a position outside flue gas duct 6. Rotation shaft 21 of the control element extends for this purpose from eccentric part 32 all the way up to movable plate 28 through the flue gas duct wall 19. This eccentric part 32 is preferably connected via a connecting rod 33 to a lever arm 37 of an actuator 22. A system of rods which allows operation of movable plate 28 with an actuator 22 is hereby obtained. The skilled person will understand that the lengths of lever arm 37, connecting rod 33 and eccentric part 32 of control element 21, 32 can be designed so as to achieve an optimal transmission of force and of movement from actuator 22 to movable plate 28. The system of rods has the advantage that heat is given minimal opportunity to transfer through the system of rods to actuator 22, since the distance over which the heat must transfer is increased considerably by the system of rods. Movable plate 28 is situated in flue gas duct 6 and, with this, is in direct contact with the flue gases such that the temperature of movable plate 28 is affected considerably by the temperature of the flue gases. The movable plate will become hot in practice. The system of rods, consisting of the control element 21 with the eccentric part 32, the connecting rod 33 and the lever arm 37 on actuator 22, prevents to maximum extent that heat flows from movable plate 28 to actuator 22. A highly reliable operation of movable plate 28 can further be achieved.
Two parts can be distinguished from each other in module 12. A first part is the part through which flue gases flow, is designated with 6 in the figure, and is typically the part which is enclosed by flue gas duct wall 19. A second part 25 is adjacent to the first part and is separated therefrom by at least a part of flue gas duct wall 19. In figure 2 this second part is formed substantially by the lower half of module 12, with the exception of the part on the far right in the figure. The second part 25 is not provided for allowing flow of flue gases. The sensors, control elements and other components which provide for a good operation of module 12 are typically placed in this second part. The second part 25 of module 12 is preferably encased so as to protect the elements in second part 25. The casing is preferably provided with ventilation openings 30 or perforations to allow a good ventilation of second part 25. Heat can be discharged in simple manner via ventilation openings 26.
A mounting wall 23 is provided in second part 25 of module 12. Mounting wall 23 is provided at a distance 24 from flue gas duct wall 19. An insulating panel 34 which reduces heat transfer from flue gas duct wall 19 to mounting wall 23 preferably extends between mounting wall 23 and flue gas duct wall 19. The distance 24 can be minimized when an insulating panel 34 with good insulating properties is provided, without reducing the reduction in heat transfer herein. In an embodiment in which no insulating panel 34 is provided, or an insulating panel 34 with fewer insulating properties is provided, the distance 24 between mounting wall 23 and flue gas duct wall 19 can be increased so as to limit heat transfer. The skilled person will understand that the distance 24 in combination with an optional insulating panel 34, in further combination with the ventilation openings 26 which are provided in second part 25 of module 12, can be adapted to each other in order to limit the maximum temperature of mounting wall 23 in a normal operating mode of module 12.
Mounting wall 23 is configured for mounting of one or more operating elements of module 12. In the embodiment of figure 2 lambda probe 15 is connected to mounting wall 23, which is designated with reference numeral 36. Actuator 22 is also connected to mounting wall 23. In the embodiment of figure 2 spacers 35 are provided between mounting wall 23 and actuator 22, which spacers 35 further reduce direct heat transfer between mounting wall 23 and actuator 22. In the configuration as seen in figure 2 the mounting of the actuator by means of spacers 35 allows lever arm 37 to extend toward flue gas duct wall 19 such that it extends closer to the eccentric part 32 of control element 21, and can thus be mounted together with connecting rod 33 in an optimal manner.
In the context of this invention the skilled person will understand that reduction of heat transfer is understood to mean that the resistance to heat transfer is directly or indirectly increased. Principles for increasing resistance to heat transfer and measuring and ascertaining thereof are generally known and are therefore not elucidated in further detail.
Throttle valve 14 with movable plate 28 divides flue gas duct 6 into two sections. A first section is shown in figure 2 in an upper half of module 12, and lies upstream of throttle valve 14. A second section is shown in figure 2 on the right-hand side of the figure, below this upper half, and lies downstream of throttle valve 14. These two sections can be deemed as separated by a partition 29 which is visible in figure 3. The skilled person will understand from a combination of figure 3 and figure 2 that partition 29 at least partially forms the flue gas duct wall 19. In the embodiment of figure 2 partition 29 extends in the flow direction of flue gases 8, and these flue gases 8 must flow around a bend in order to flow to the second section. In an alternative configuration the partition 29 can be placed transversely of the flow direction of flue gases 8, so that the flue gases can flow straight through throttle valve 14 when throttle valve 14 is open.
Partition 29 has an opening 27 which is smaller than partition 29. Movable plate 28 is formed such that in a first position, this being the position as shown in figures 2 and 3, it almost wholly covers opening 27. Air is hereby prevented to maximum extent from flowing through opening 27. Throttle valve 14 can then be deemed as closed. Movable plate 28 can be moved to a second position (not shown), in which movable plate 28 extends adjacently of opening 27 and thereby does not cover the opening appreciably. Air can hereby flow unimpeded through opening 27. A first stop 30, which establishes a first end position of movable plate 28, more specifically the first position, is preferably provided. This stop 30 will stop the movement of movable plate 28 toward the first position when plate 28 reaches an optimal first position. The movement of movable plate 28 is designated in the figure with arrow 44. A second stop 31 is preferably further provided, which stops the movable plate in the second position. When movable plate 28 moves toward the second position, it will hit second stop 31 when an optimal second position is reached. Physical boundaries for movement 44 of movable plate 28 are established by providing first stop 30 and second stop 31. The skilled person will understand that the embodiment described here and shown in figures 2 and 3 is only a preferred embodiment of a throttle valve 14. Throttle valves having a similar functionality can also be constructed on the basis of other principles, such as with a tilting plate which rotates relative to the partition instead of sliding relative to the partition, as described above.
Figure 3 shows the system of rods for operating movable plate 28. Movable plate 28 is connected to an eccentric part 32 via the control element extending through flue gas duct wall 19 via a rotation shaft 21. The eccentric part 32 and the rotation shaft 21 can be formed integrally or can be made from a plurality of pieces and be fixedly connected to each other. The position of eccentric part 32 and movable plate 20 is fixed via the rotation shaft. Rotation of eccentric part 32 of the control element will therefore result in a corresponding rotation of movable plate 28 around rotation shaft 21. Actuator 22 has a lever arm 37 which is provided on the shaft of actuator 22. This lever arm 37 is connected via a connecting rod 33 to the eccentric part 32 of the control element. Rotation of the actuator, as illustrated with arrow 38, will therefore bring about a rotation of eccentric part 32, whereby movable plate 28 is also moved. This construction allows actuator 22 to be positioned at a distance from movable plate 28, such that heat transfer from movable plate 28 to actuator 22 is minimal. The skilled person will understand that this is only a preferred embodiment for driving of movable plate 28, and that alternative embodiments can be envisaged.
Figure 3 further shows how lambda probe 15 is connected via mounting elements 36 to mounting wall 23. The mounting wall of the embodiment of figure 2 is preferably provided with a substantially flat side and a side with mounting elements. The substantially flat side can be directed toward the flue gas duct wall and can be placed at a distance therefrom, so that no or no appreciable heat or cold bridges are created between the mounting wall and the flue gas duct wall. The connecting elements can then be used to connect elements such as lambda probe 15 and/or actuator 22 to mounting wall 23.
Figure 2 further shows a fan 13. In the embodiment of figure 2 fan 13 is placed in the second section of flue gas duct 6. Fan 13 has blades 40 which extend in flue gas duct 6 in order to drive the flue gases. In the example of figure 2 blades 40 are radial blades for drawing the air centrally into the fan and accelerating it radially relative to the fan in the direction of arrow 9. Blades 40 are driven by a motor 39 for the fan. This motor is placed in the second part 25 of module 12 so that the motor can be cooled by air which can flow through the ventilation openings 26 in the second part. The airflow can be driven by fan 13. Fan 13 in combination with throttle valve 14 allows the speed and/or the flow rate of the airflow to be controlled.
In the embodiment of figure 2 module 12 further comprises a pressure gauge 41. In the embodiment of figure 2 pressure gauge 41 is connected to an opening 42 which is situated upstream of throttle valve 14 in flue gas duct 6. In the embodiment of figure 2 pressure gauge 41 is further connected to an opening 43 situated downstream of throttle valve 14. This allows pressure gauge 41 to measure two pressures, upstream and downstream of throttle valve 14. The control of module 12 and, in line therewith, the control of stove 1, can be optimized on the basis of these pressures or on the basis of a pressure difference. Instead of or in addition to pressure gauge 41 it is possible to add other sensors in the module, for instance temperature sensors or soot sensors, in order to gauge a state of module 12 and/or of flue gases 6 and/or of a component of module 12. Communication modules or connections for cabling can further be provided in the second part 25 of module 12 in order to allow the different components of module 12, particularly actuator 22, lambda probe 15 and optional other gauges such as pressure gauge 41, to communicate with components of stove 1 which are situated at a distance from module 12.
Module 12 is preferably further provided with a self-closing valve, which is designated in figures 1 and 2 with reference numeral 44. By providing a mechanical one-way valve in the flue gas discharge an unsafe situation, for instance when two stoves are provided in a residential unit and are connected to one chimney, and when one of the stoves loses power, is avoided. This is because combustion air from a different stove can never flow back via the flue gas discharge into the stove owing to mechanical one-way valve 44, because the mechanical one-way valve prevents such a flow irrespective of the state of valve 14.
The skilled person will appreciate on the basis of the above description that the invention can be embodied in different ways and on the basis of different principles. The invention is not limited here to the above described embodiments. The above described embodiments and the figures are purely illustrative and serve only to increase understanding of the invention. The invention is not therefore limited to the embodiments described herein, but is defined in the claims.

List of reference numerals

1: stove
2: combustion chamber
3: transparent material
4: fire
5: supply for combustion air
6: discharge for flue gases
7: airflow combustion air
8: flue gases
9: flow of flue gases to chimney
10: fuel supply
11: reservoir
12: module
13: fan
14: throttle valve
15: lambda probe
16: operative connection
17: controller
18: user interface
19: flue gas duct wall
20: opening lambda probe
21: control element/rotation shaft
22: actuator
23: mounting wall
24: distance (flue gas duct wall - mounting wall)
25: second part of module
26: ventilation opening
27: opening
28: movable plate
29: partition
30: stop first position
31: stop second position
32: eccentric part of control element
33: connecting rod
34: insulating panel
35: spacers
36: mounting of lambda probe on mounting wall
37: lever arm
38: servomotor movement
39: motor for ventilation
40: blades of fan
41: pressure gauge
42: opening for measuring pressure upstream of throttle valve
43: opening for measuring pressure downstream of throttle valve
44: self-closing valve

Claims

Module for discharging flue gases, comprising a frame with a flue gas duct extending through the frame, wherein the flue gas duct is delimited by a flue gas duct wall and wherein a throttle valve is provided in the flue gas duct, wherein a control element for opening and closing the throttle valve further extends through the flue gas duct wall between the throttle valve and an actuator, wherein the frame further comprises a mounting wall for mounting of the actuator, and wherein the mounting wall is provided at a distance from the flue gas duct wall in order to prevent direct heat transfer from the flue gas duct wall to the actuator.
Module according to claim 1, wherein the flue gas duct wall sub-divides the frame into a first part which is provided to enclose the flue gases and a second part, wherein the frame has ventilation openings in the second part.
Module according to any of the foregoing claims, wherein the throttle valve is formed by mounting a plate movably relative to a fixedly positioned opening in the flue gas duct, such that the plate is movable between a first position in which the plate substantially closes the opening and a second position in which the plate impedes an airflow through the opening to minimal extent.
Module according to claim 3, wherein the fixedly positioned opening is formed in a partition in the flue gas duct and wherein the plate is mounted parallel to the partition and is rotatable around a rotation axis which is oriented perpendicularly of the partition.
Module according to claim 3 or 4, wherein the plate is fixedly connected to a control element which is movable by the actuator via an intermediate element so as to move the plate between the first position and the second position.
Module according to claim 4 and 5, wherein the control element is positioned eccentrically relative to the rotation axis and wherein the intermediate element is formed as a connecting rod.
Module according to any of the foregoing claims, wherein an insulating panel is provided between the flue gas duct wall and the mounting wall.
Module according to any of the foregoing claims, wherein the actuator is connected to the mounting wall via spacers.
Module according to any of the foregoing claims, wherein the mounting wall and the flue gas duct wall have an opening which in mounted state is aligned such that a lambda probe can be placed through the opening and can be mounted against the mounting wall.
Module according to any of the foregoing claims, wherein the actuator is formed as a servomotor, wherein a lever arm is provided on a rotation shaft of the servomotor, which lever arm has an eccentric connection for connecting to the control element.
Module according to any of the foregoing claims, operatively connected to a fireplace comprising a combustion chamber with a flue gas discharge, and wherein the module is mounted at a distance of at least 1 metre, preferably at least 2 metres, more preferably at least 3 metres and at a distance of a maximum of 10 metres, preferably a maximum of 8 metres, more preferably a maximum of 6 metres from the combustion chamber of the fireplace.
Fireplace with a combustion chamber and an active combustion air flow controller which is operatively connected to the fireplace for the purpose of controlling an airflow through the combustion chamber, wherein the active combustion air flow controller is formed by a module according to any of the foregoing claims.