EP2083111A1 - Heating device for a household device for caring for pieces of laundry and method for operating such a heating device - Google Patents

Abstract

The device (1) has a gaseous medium supplying device (3) supplying a gaseous medium e.g. gaseous fuel, to a burner (2). A pipeline (7) is thermally coupled to the burner and the supplying device, and changes temperature of the supplying device to control flow of the medium through a metering unit (5) of the supplying device. The pipeline is designed so that the flow of the gaseous medium through the supplying device is reduced during an increase of the temperature of the supplying device by the pipeline, where the supplying device has a dosing unit e.g. nozzle. An independent claim is also included for a method for operating a heating device for a household appliance for care of laundry items.

Description

The invention relates to a heating device for a domestic appliance for the care of laundry, which is designed to generate heat by combustion of gaseous media, and having a device for supplying the gaseous medium to a burner. Furthermore, the invention relates to a method for operating such a heating device for a domestic appliance for the care of laundry items.

There is known a gas laundry dryer, which is formed with a heater which is constructed only in one stage in the heating power, so that a control of the generation of heat is possible only by turning on and off the heater. In an on state, the full available heating power is essentially always introduced. Via bimetallic temperature switches or NTC resistors ("NTC" means "Negative Temperature Coefficient") is then a regulation on the switching on and off of the gas burner by optionally cyclically repeated opening and closing of the gas valve possible. An adaptation of the heating power of the gas burner and thus a reduction in the load of the gas burner, especially in critical exhaust air and air resistance situations, such as an added lint filter, is not possible.

A control of the heating power is possible in accordance with conventional practice only via a multi-stage gas valve or via a continuously or multi-stage working gas control valve. However, such valves are much too expensive for use in dryers in the low price segment and are therefore not used there.

It is an object of the present invention to provide a heating device for a domestic appliance for the care of laundry items and a method for operating such a heater, in which or with which the control of the heating power can be multi-level and thus flexible even in household appliances without a complex gas control valve is.

This object is achieved by a heating device having the features of claim 1, and a method comprising the features of claim 16.

A heating device according to the invention for a domestic appliance for the care of laundry items is designed to generate heat by combustion of gaseous media. The heating device comprises a device for supplying the gaseous medium to a burner of the heating device. In addition, the heating device comprises at least one means, which is thermally coupled to the burner and the device and is designed to change a temperature of the device for controlling the flow of the gaseous medium through the device.

This embodiment of the heater can ensure that even without a relatively complex gas control valve, a flexible and thus multi-level control of the heating power can be done. By the means and its thermal coupling with the burner and the device thus the flow rate of the medium can be adjusted by the device temperature dependent. The invention thus relates to a self-regulating burner system of a heating device, in particular a gas burner system, which can adapt to different resistance situations in the domestic appliance and reduce or increase the heat output. The invention makes use of specific behaviors of a flame of the gaseous medium (in particular a gas flame, with different air volume flows over the burner). At a high volume flow over the burner, the gas burner flame is short and small in diameter. If the volume flow through the burner is reduced by adding, for example, the lint filter or other air-reducing influences, for example a long exhaust pipe, the flame opens outwards in a similar way to a tulip and the flame also becomes longer. A further aspect in this context is given by the burner output of a burner, in particular a gas burner, being determined by the volume flow of the gaseous medium, in particular the fuel gas, or the molecular weight of the gaseous medium. If, for example, the temperature of the gaseous medium in front of a metering unit for metering the gaseous medium, in particular a pressure regulating valve, increases, the same volume is still supplied via this metering unit to the burner, which is the molar mass contained in the volume but lower at a higher temperature due to the expansion of the gas, whereby the burner load decreases and the heating power can be reduced.

Just these properties mentioned are exploited by the heating device according to the invention in an advantageous manner by quasi by the thermal coupling of the means with the burner and the device exactly the flow control can be guaranteed depending on the temperature of the device and thus the heating power very flexible and multi-level, in particular continuous, changeable.

Preferably, the means of the heater is configured such that as the temperature of the device is increased by the means, the flow rate of the gaseous medium through the device is reduced.

The means is preferably designed for detecting the temperature in the region of the flame of the burner. Thus, the temperature can be ascertained virtually in the region of the burner flame, which also allows conclusions to be drawn about the shaping and widening of the burner flame, and thus also an undesirable flame profile can be detected. Depending on this, the flow of the gaseous medium through the device can then be automatically changed by the thermal coupling of the device.

Such a self-regulation is highly precise and flexible and allows a very finely metered adjustment or regulation and thereby also a very finely adjustable Heizleistungsänderung.

Preferably, the means for changing the temperature of the gaseous medium is formed. It is thus achieved by the means quasi also a direct thermal feedback with the guided in the device gaseous medium, whereby the above-mentioned behaviors can be exploited particularly effectively in order to adjust the heating power control of the heater can.

Preferably, the device comprises a metering unit, in particular a nozzle, for metering the gaseous medium. The metering unit can also be a pressure regulating valve.

In particular, the means for changing the flow cross-section of the metering unit is formed by a temperature application of the metering unit. It can thus be made possible a direct action on the flow cross-section of the metering unit, whereby here too the precise adjustment and rapid change of the cross section and thus a fast control of the heating power can be done.

Preferably, the means comprises a heating unit, which is thermally coupled to the device and is electrically controllable depending on the temperature in the region of the burner. The central component in this embodiment is thus an electric heating unit which can actively heat the device, in particular a supply line for the gaseous medium to the burner, in the device. This heating unit is preferably with a temperature monitoring device, in particular a temperature controller, which monitors the burner heater, in particular the gas burner heater, and this switches on or off. Depending on the temperature gradient on this control element, the air resistance state can be detected in the domestic appliance. With high air resistance, this heating unit is turned on, the gaseous medium expands and the burner load drops. At a normal air resistance, the heating unit remains off.

It can also be provided that the heating means comprises a heat exchanger as means. Also by this, the thermal coupling can be provided with the burner and the device to the effect that a temperature change of the device for controlling the flow of the medium through the device by means of this heat exchanger can be made.

In a preferred embodiment, the means is at least one heating and cooling element, in particular a Peltier element, which is controlled depending on the temperature in the region of the burner for heating or cooling the device, in particular the metering unit, and thermally coupled with this device. In this embodiment, a central component is given by this heating and cooling element, which with the Device, in particular a supply line for supplying the gaseous medium to the burner is coupled. Such a heating and cooling element is arranged so that it can actively heat the device, in particular the supply line, but can actively cool by reversing polarity. Such a system, in particular Peltier system is controlled by a temperature controller, which monitors the burner heater, in particular the gas burner heater. Depending on the temperature gradient on the control element, the air resistance state in the device can be detected. At high air resistance, the heating and cooling element is switched to "heating", the gaseous medium expands in the device in front of the burner and the burner output drops. In a normal air resistance of this system, especially Peltier system, off.

Since the burner output in such a domestic appliance for the care of laundry items, in particular a tumble dryer in principle with the process time by warming the gas-conducting components, which include, for example, the valve, a nozzle and pipes, decreases (about 5 to 10% power loss), this behavior can active cooling of the Peltier system can be compensated. It is even possible to increase the heating capacity above the nominal value of the burner load, which leads to a shortening of the drying time.

In a further advantageous embodiment, a central component is the metering unit of the heating device, in particular a gas burner nozzle, which is thermally coupled from at least two sides with such heating and cooling elements. The dosing unit can thus either be cooled or heated by reversing polarity. This system can also be controlled via a temperature controller that monitors the gas burner heating. Depending on the temperature gradient on the control element, the air resistance state in the device can be detected. Again, with high air resistance, the Peltier system can be switched to "cooling", so that the diameter and thus the flow cross-section of the metering unit, in particular the nozzle, reduced, and the flow rate is lowered and thus the burner output is lowered. With normal air resistance, the Peltier system is simply turned off.

As the burner power in a household appliance for the care of items of laundry, especially a tumble dryer, basically with the process time by warming up the Gas-conducting components, as already mentioned above, sinks, as has also already been mentioned above, this behavior can be compensated for by active heating of the dosing unit, leading to a larger diameter and thus a larger flow cross-section of the dosing unit and thus a higher Volumetric flow of the gaseous medium is ensured by the metering unit. It is even possible to increase the heating power above the nominal value of the burner load, which leads to a shortening of the drying time.

The means may comprise at least one heating element, in particular a Peltier element, which is controllable and thermally coupled depending on the temperature in the region of the burner for heating the device, in particular a feed line for supplying the gaseous medium to the burner. In this embodiment, therefore, in addition to or instead of the above-mentioned procedure, not or not only the metering unit can be subjected to a corresponding temperature, but a further component of the device, in particular the supply line, can be correspondingly thermally coupled.

Preferably, the means comprises a conduit which is thermally coupled to the device for supplying the gaseous medium to the burner and to the burner, and in which a medium is arranged which depends on the temperature loading of the device, in particular the gaseous medium transported therein via the conduit wall from its own temperature exposure by the burner, in particular the burner flame, is formed. In this embodiment, a central component is to be seen in that the line is provided, which is at least partially filled in particular with a gaseous medium. Preferably, the line is formed around a supply line associated with the device for supplying the gaseous medium to the burner and also extends in the region of the burner flame. In particular, this line is wound around the feed line. Furthermore, it is preferably provided that the line is arranged on the inside of a channel arranged around the burner head. The line is preferably formed of a good heat conducting material, for example copper. The medium present in the line can be a liquid which has good thermal conductivity.

During normal operation of the domestic appliance, the burner flame is bundled relatively strongly and the heat-conducting medium arranged in this line assumes the temperature of the wall of the heating channel at the burner head. This temperature is usually below 40 ° C.

If there are now increased air resistance in the domestic appliance, the gas flame opens to the outside and the temperature of the heat-conducting medium arranged in the conduit increases substantially. This medium then conducts the heat to the supply line of the device with which it is thermally coupled, and thus heats the gaseous medium in this supply line. This gaseous medium in the supply line then expands and the burner power decreases according to the principles explained above. This also allows the heating power of the heater selbstregelnd precise and continuous.

Another aspect of the invention relates to a domestic appliance for the care of laundry items, in particular a gas laundry dryer, which has a heating device according to the invention or an advantageous embodiment thereof.

In a method according to the invention for operating a heating device for a domestic appliance for the care of laundry items, a gaseous medium is fed via a device for supplying this gaseous medium to a burner of the heating device. A means is thermally coupled to the burner and the apparatus, wherein the means changes the temperature of the apparatus operating phase specific and, depending on the temperature change, the flow of the medium through the apparatus is operating phase specific. This also makes it possible to regulate the heating power very precisely and in several stages, in particular continuously, and this can be done in particular in domestic appliances which have no gas valve designed for multi-stage control.

Fig. 1

eine perspektivische Darstellung einer erfindungsgemäßen Heizeinrichtung gemäß einem Ausführungsbeispiel;

Fig. 2

eine schematische Schnittdarstellung eines Teilbereichs der Heizeinrichtung gemäß Fig. 1; und

Fig. 3

eine schematische Schnittdarstellung eines weiteren Ausführungsbeispiels eines spezifischen Ausschnitts einer erfindungsgemäßen Heizeinrichtung.

Embodiments of the invention are explained in more detail below with reference to schematic drawings. Show it:

Fig. 1

a perspective view of a heating device according to the invention according to an embodiment;

Fig. 2

a schematic sectional view of a portion of the heater according to Fig. 1 ; and

Fig. 3

a schematic sectional view of another embodiment of a specific section of a heater according to the invention.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

In Fig. 1 is shown in a schematic perspective view of a heater 1, which is arranged in a gas scrubber dryer. The heater 1 is designed to generate heat by burning a gaseous medium. The heating device 1 further comprises a device 3 for supplying the gaseous medium to a burner 2. The device 3 comprises a supply line 4 for supplying this gaseous medium to the burner 2 and moreover has a metering unit, which is designed as a nozzle 5 in the embodiment , The nozzle 5 is preferably a simple and inexpensive component, which is not designed as a multi-stage gas control valve.

The nozzle 5 is arranged in the flow direction of the gaseous medium in the supply line 4 in front of the burner 2.

The heater 1 further comprises a heating channel 6, which is tube-like and into which the burner 2 extends at least partially.

The heating device 1 further comprises a means which is thermally coupled to the burner 2 and the device 3 and is designed to change a temperature of the device 3 for controlling the flow of the gaseous medium through the device 3.

In Fig. 1 In this regard, an embodiment is shown in which the means comprises a pipe 7 which is at least partially attached to the outside of the feed line 4 or arranged surrounding it. In particular, this line 7 is wound around the feed line 4. In addition, this line 7 extends in the area to the burner 2. In particular, the line 7 in the region of the burner head 8 ( Fig. 2 ) is arranged on an inner side of the heating channel 6. Preferably, this portion of the conduit 7, which is arranged adjacent to the burner head 8, extends around the burner head 8, and at least partially annularly surrounding it. As in this regard from the illustration according to Fig. 2 can be seen, this portion of the line 7 is positioned adjacent to the burner flame 9 and 10 respectively. The thermal coupling to the burner 2 or to the burner head 8 and in particular to the burner flame 9 or 10 is thereby given particularly effective.

The conduit 7 forming means is thus thermally coupled to the device 3 and the burner 2 and formed so that in the conduit 7, a good heat-conducting medium, in particular a heat-conducting liquid, is arranged. This heat-conducting medium is designed to apply the temperature of the device 3, in particular the transported in the feed line 4 gaseous medium. This temperature is applied via the walls of the conduit 7 and the supply line 4, wherein the temperature is applied by the burner 2, in particular the burner flame 9, 10, depending on its own temperature exposure of the heat-conducting medium arranged in the conduit 7.

The conduit 7 is formed as a pipeline and formed of a copper-containing material. As a conductor material, another thermally conductive material may be provided.

The execution according to Fig. 1 the heater 1 makes use of behaviors of the gas flames or the burner flames 9 and 10 at different air flow rates over the burner 2 advantage. In this context, at a high volume flow over the burner 2, the gas burner flame 9 and 10 is short and small in diameter. If the volume flow over the burner 2 is reduced by adding the lint filter (not shown) to the gas scrubber or other air-reducing factors, such as a long exhaust pipe, etc., the burner flame 9 or 10 opens outward like a tulip and the flame also becomes longer , Another mode of behavior is characterized in that the burner output of the gas burner 3 is determined by the volume flow of the fuel gas or the molecular weight of the fuel gas. For example, increases the temperature of the fuel gas the pressure control valve or the nozzle 5 on, although the same volume is still supplied to the gas burner 2 via the pressure regulator, but the molecular mass contained in the volume is lower at a higher temperature due to the expansion of the gas and the burner load decreases. By combining these two behaviors, a self-regulatory system can be implemented Fig. 1 be enabled. In this case, the burner flame is strongly bundled in normal operation of the gas scrubber dryer and the liquid in the conduit 7 takes the temperature of the wall of the heating channel 6 at the burner head 8 a. This temperature is usually below 40 ° C. If there are now increased air resistance in the scrubber dryer, the gas flame 9 opens to the outside, so that the gas flame 10 is formed and the temperature of the liquid in the line 7 increases significantly. This liquid in the line 7 conducts the heat to the gas supply pipe or to the supply line 4 and thus heats the flowing gaseous medium in this supply line 4 in front of the nozzle 5. The gaseous medium in the supply line 4 expands and due to the above-described behaviors decreases the burner output.

It can also be provided that the agent additionally or instead of according to Fig. 1 and Fig. 2 explained embodiments with the line 7 as a central component has an electric heater that can actively heat the supply line 4. This electrical heating unit is preferably switched on or off via a temperature controller which monitors the gas burner heating. Depending on the temperature gradient on the control element, the air resistance state in the device can be detected. At high air resistance, the electric heating unit is turned on, the gaseous medium in the supply line 4 expands and the burner power drops. At normal air resistance, this electric heater remains off.

In a further embodiment, which is not explicitly shown, it can be provided that the means for changing a temperature of the device for controlling the flow of the medium through the device 3 comprises at least one Peltier element, which is arranged so that it activates the supply line 4 Heating or by reversing can also actively cooling. This Peltier system is controlled by a temperature controller, which monitors the gas heating. Depending on the temperature gradient on the control element, the air resistance state in the device can be detected. At high air resistance, the Peltier system is set to "heating" switched, the gaseous medium transported in the supply line 4 expands and the burner power drops. With normal air resistance, the Peltier system is switched off.

Since the burner output in gas scrubbers basically decreases with the process time by warming up the gas-carrying components (valve, nozzle, pipelines etc.) (about 5 to 10% power loss), this behavior can be compensated by active cooling of the Peltier system, or it is even possible , thus increasing the heating power above the nominal value of the burner load, which leads to a shortening of the drying time.

In Fig. 3 is a schematic sectional view of another embodiment of the heater 1 shown in a partial section. In this embodiment, the means comprises at least two heating and cooling elements, in particular two Peltier elements 11 and 12, which are arranged adjacent to the dosing unit. The metering unit is designed in this embodiment as a nozzle 5, wherein it may be formed in the other embodiments already explained as a pressure control valve.

The nozzle 5 is equipped from two sides with the Peltier elements 11 and 12, so that they can either cool or heat the nozzle 5, which can be done by reversing the polarity. This Peltier system can be controlled by a temperature controller, which monitors the gas burner heating. Depending on the temperature gradient on the control element, the air resistance state in the device can also be detected here. At high air resistance, the Peltier system is switched to cooling, so that automatically reduces the diameter of the nozzle 5 and thus the flow cross-section of the nozzle 5, and the flow rate through the nozzle 5 is lowered, which also causes the burner output decreases. With normal air resistance, the Peltier system is simply turned off.

Since the burner output in tumble dryers generally decreases with the process time by warming up the gas-conducting components, as already mentioned above, by a proportion, as also already mentioned above, this behavior can be achieved by active heating of the nozzle 5, which leads to a larger one Diameter of the nozzle 5 leads and thus to a higher gas flow rate, be compensated, or it is even it is possible to increase the heating capacity above the nominal value of the burner load, which leads to a shortening of the drying time.

Claims (16)

Heating device for a domestic appliance for the care of laundry items, which is designed to generate heat by combustion of gaseous media, with a device (3) for supplying the gaseous medium to a burner (2), characterized by a means (7, 11, 12 ) which is thermally coupled to the burner (2) and the device (3) and for changing a temperature of the device (3) for controlling the flow of the medium through the device (3), in particular the metering unit (5) of the device ( 3) is formed. Heating device according to claim 1, characterized in that the means (7, 11, 12) is designed such that when the temperature of the device (3) is increased by the means (7, 11, 12) the flow of the gaseous medium through the Device (3) is reduced. Heating device according to claim 1 or 2, characterized in that the means (7, 11, 12) for detecting the temperature in the region of a flame (9, 10) of the burner (2) is formed. Heating device according to one of the preceding claims, characterized in that the means (7, 11, 12) is designed to change the temperature of the gaseous medium. Heating device according to one of the preceding claims, characterized in that the device (3) has a metering unit (5), in particular a nozzle or a valve for metering the gaseous medium. Heating device according to claim 5, characterized in that the means (7, 11, 12) for changing the flow cross-section of the dosing unit (5) by applying temperature to the dosing unit (5) is formed. Heating device according to one of the preceding claims, characterized in that the means (7, 11, 12) comprises a heating unit, which is thermally coupled to the device (3) and depending on the temperature in the region of the burner (2), in particular the burner flame (9, 10), is electrically controllable. Heating device according to one of the preceding claims, characterized in that the means (7, 11, 12) comprises a heat exchanger. Heating device according to one of the preceding claims, characterized in that the means (7, 11, 12) at least one heating and cooling element (11, 12), in particular a Peltier element, which depends on the temperature in the region of the burner (2) for heating or cooling the device (3), in particular the dosing unit (5), controllable and thermally coupled with this. Hinge device according to one of the preceding claims, characterized in that the means (7, 11, 12) comprises at least one heating element, in particular a Peltier element, which depends on the temperature in the region of the burner (2) for heating the device (3), in particular a feed line (4) for supplying the gaseous medium to the burner (2), controllable and thermally coupled thereto. Heating device according to one of the preceding claims, characterized in that the means (7, 11, 12) comprises a line (7) which is thermally coupled to the device (3) and to the burner (2), and in which a medium is arranged, which for the temperature of the device (3), in particular the transported therein gaseous medium, via the wall of the conduit (7) depending on its own Temperaturbeaufschlagung by the burner (2), in particular the burner flame (9, 10) is formed , Heating device according to claim 11, characterized in that the line (7) around one of the device (3) associated feed line (4) and extending in the region of the burner flame (9, 10). Heating device according to claim 12, characterized in that the line (7) is wound around the feed line (4). Heating device according to claim 12 or 13, characterized in that the line (7) on the inside of a burner head (8) arranged channel (6) is arranged. Domestic appliance for the care of laundry items, in particular gas laundry dryer, which has a heating device (1) according to one of the preceding claims. Method for operating a heating device (1) for a domestic appliance for the care of laundry items, in which a gaseous medium is fed via a device (3) to a burner (2) of the heating device (1), characterized in that the burner (2 ) and the device (3) a means is thermally coupled, by which the temperature of the device (3) changes and depending on the change in temperature, the flow of the gaseous medium through the device (3), in particular a metering unit (5) of the device (3 ), is changed.

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