US20050016520A1

US20050016520A1 - Heating configuration for a drier

Info

Publication number: US20050016520A1
Application number: US10/893,662
Authority: US
Inventors: Heinz Freese; Thomas Nawrot; Gunter Steffens
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2003-07-16
Filing date: 2004-07-16
Publication date: 2005-01-27
Also published as: GB2404002A; GB0414220D0; GB2404002B; DE10332339A1

Abstract

A heating configuration for a drier, particularly a laundry drier, has a burner with a burner head, a first heating channel with an inlet opening and an outlet opening, and a second heating channel with an inlet opening and an outlet opening. The cross-sectional area of the second heating channel is greater than the cross-sectional area of the first heating channel. The burner projects through its inlet opening into the first heating channel and an outlet portion of the first heating channel projects into an inlet portion of the second heating channel. A guide device is provided in an upper section of the first heating channel adjacent to the outlet opening thereof in order to downwardly deflect hot gases which flow from the burner head in a direction towards the outlet opening of the second heating channel.

Description

BACKGROUND OF THE INVENTION

Field of the Invention
The present invention relates to heating configuration for a drier, particularly for a laundry drier.
U.S. Pat. No. 1,311,235 discloses a gas burner having a burner head which projects through an inlet opening of a heating channel. An annular opening between the inlet opening and the burner serves as an air entry. The distal end of the heating channel projects by an outlet opening thereof into an inlet of a further heating channel having a greater diameter than the first heating channel. An annular area between the first heating channel and the further heating channel serves as a further air entry opening.
The prior art configuration of burner and heating channels is disadvantageous in that the temperature distribution is non-uniform in the channels.
There is therefore a need for a heating configuration for a drier, particularly for a laundry drier, in which the temperature distribution in the heating channel is as uniform as possible so that a more reliable operation of the heating configuration is ensured and improved temperature regulation is possible.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a heating configuration for a drier which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type.
With the foregoing and other objects in view there is provided, in accordance with the invention, a heating configuration for a drier, such as a laundry drier, comprising:

- a burner with a burner head;
- a first heating channel having an inlet portion formed with an inlet opening and an outlet portion formed with an outlet opening;
- a second heating channel having an inlet portion formed with an inlet opening and an outlet portion formed with an outlet opening;
- the second heating channel having a cross-sectional area greater than a cross-sectional area of the first heating channel, the outlet portion of the first heating channel projecting into the inlet portion of the second heating channel, and the burner projecting into the first heating channel through the inlet opening thereof; and
- a flow guide in an upper part of the first heating channel adjacent the outlet opening thereof and configured to downwardly deflect a flow of gas flowing in a direction from the burner head towards the outlet opening of the second heating channel.

Preferably, the burner head is disposed in the first heating channel.
In other words, according to the present invention there is provided heating configuration for a drier, particularly a laundry drier, that has a gas burner with a burner head, a first heating channel with an inlet opening and an outlet opening and a second heating channel with an inlet opening and an outlet opening and a cross-sectional area which is greater than the cross-sectional area of the first heating channel, wherein the burner head projects into the inlet opening of the first channel and the outlet opening of the first heating channel projects into the inlet opening of the second heating channel, a guide device being provided in the upper section of the first heating channel adjacent to the outlet opening thereof in order to downwardly deflect hot gases which flow from the burner head in direction to the outlet opening of the second heating channel.
Due to the fact that the heating configuration has a guide device in the upper section of the first heating channel adjacent to the outlet opening thereof, whereby hot gases which flow from the burner head in direction towards the outlet opening of the second heating channel are deflected downwardly, it is thereby possible to guide hot air or hot gases, which flows or flow out of the first heating channel and which due to air lift has or have a tendency to flow upwardly, into the middle section of the second heating channel so that overheating of the upper section of the second heating channel is avoided. Through provision of the guide device it is therefore possible to achieve a more uniform temperature distribution over the cross-sectional area. Moreover, supplementary air, which due to the provision of the guide device in the upper section of the first heating channel is better mixed with hot gases flowing out of the first heating channel, enters the second heating channel between the outlet opening of the first heating channel and the inlet opening of the second heating channel. Due to the better mixing of the supplementary air and the hot gases flowing out of the first heating channel and thus a more uniform temperature distribution over the cross-section of the second heating channel, hot zones within the second heating channel are avoided, which ensures a more reliable operation of the heating configuration. By virtue of the uniform temperature distribution in this heating channel arrangement a more precise detection of the temperature of the gases disposed in the heating channel arrangement is possible so that a more precise temperature regulation can be undertaken.
In accordance with an advantageous feature of the invention, the guide device is constructed as an inclined wall which extends at a downward slope in flow direction from a middle upper section of the first heating channel to the outlet opening of the first heating channel. A flame that issues from the burner and has already mixed with first supplementary air which has entered between the burner and the inlet opening of the first heating channel is thereby conducted downwardly in the outlet region of the first heating channel. This is advantageous, since the flame issuing from the burner head flows upwardly due to heat lift and is conducted downwardly at the end of the first heating channel by the guide device.
In accordance with an preferred feature of the invention, the inclined wall is integrated in the end section of the first heating channel. This is particularly advantageous when the heating channel is made of sheet metal so that for formation of the guide device it is merely necessary to downwardly indent the upper end section adjacent to the outlet opening of the first heating channel by means of a stamping device. A particularly simple and advantageous construction of the guide device is thereby provided. Moreover, through construction of the guide device in that manner the inlet opening for supplementary air between the first heating channel and the second heating channel is enlarged in the region of the guide device so that supplementary air can flow in more easily and thus in greater quantity in this region. The upper side of the second heating channel is thus supplied with more supplementary air, which counteracts overheating of the upper side of the second heating channel.
Preferably, the first heating channel is arranged in the lower section of the second heating channel. The first heating channel is therefore arranged at the second heating channel to be eccentrically offset downwardly, so that the air entry opening for supplementary air between the first heating channel and the second heating channel is formed principally at the upper side of the second heating channel. Due to this measure it is possible for hot gases, which issue from the first heating channel and which due to heat lift preferentially flow upwardly in the upper region of the second heating channel, to better mix with supplementary air so that the effect of improved intermixing and more uniform temperature distribution is reinforced by introduction of the first heating channel into the lower section of the second heating channel. In an advantageous embodiment the front lower section of the first heating channel is connected with the rear lower section of the second heating channel by fastening elements.
In accordance with an additional feature of the invention, the burner is arranged in the lower section of the first heating channel. The hot flame which issues from the burner head and which equally has a tendency to flow upwardly due to heat lift, is thereby better retained in the middle section of the first heating channel upstream of the burner head and better mixed with the supplementary air entering between the burner and the inlet opening of the first heating channel. A more uniform distribution is thereby achieved in the first heating channel.
For preference there is arranged at the outlet opening of the second heating channel a deflection channel by which the hot gases are deflected upwardly. This deflection channel preferably has an inclined plane which extends obliquely upwardly from the lower middle section of the deflection channel in flow direction. By virtue of this inclined plane a form of baffle plate is provided, at which the hot gases or the hot air is or are not only deflected upwardly, but also mixed more uniformly over the cross-section.
Overall, formation of hot ‘temperature strands’ and hot air stratification and hot regions are avoided in the afore-described heating configuration.
In an advantageous embodiment an air conveying device is arranged downstream of the outlet opening of the second heating channel in order to provide conveying of the air from the burner in direction towards the deflection channel.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a heating configuration for a drier, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a heating configuration for a drier according to the invention;
FIG. 2 is a side view of the heating configuration of FIG. 1;
FIG. 3 is a plan view of the heating configuration of FIG. 1; and
FIG. 4 is a cross-section along the line IV-IV in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a heating configuration comprising a burner 1 with a burner head 2, a first heating channel 3, a second heating channel 4 and a deflection channel 5. The first heating channel 3 is a cylindrical or possibly oval pipe section made of sheet metal and formed with an inlet opening 6 and an outlet opening 7. The second heating channel 4 is a cylindrical pipe length 9 which is made of sheet metal and has an inlet opening 10 and an outlet opening 11. The first heating channel 3 has a smaller diameter than the second heating channel 4. The first heating channel 3 projects by an outlet portion thereof in overlapping manner into an inlet portion of the second heating channel and the first heating channel 3 is arranged on the underside of the second heating channel 4 and connected therewith. The burner 1 projects into the inlet portion of the first heating channel 3 in such a manner that the burner head 2 is arranged in the lower section, thus below a centerline 12, of the first heating channel 3.
An approximately circular first air entry opening 13, by way of which first supplementary air 14 can enter the first heating channel 3, is formed between the burner 1 and the perimeter of the inlet opening 6 of the first heating channel. Adjacent to the outlet opening 7 of the first heating channel 3 and at the upper end section of the first heating channel 3 there is provided a guide device 15 which forces the hot air or gases, which flows or flow through the first heating channel 3, downwardly in the region of the outlet opening 7 of the first heating channel 3 so that the hot air or gases enters or enter the lower portion of the second heating channel 4. The guide device 15 is formed integrally with the cylindrical pipe length 8 of the first heating channel in that an upper end section of the cylindrical pipe section 18 is deformed into a slightly concave indentation 16 by means of a stamping process or bending process. The indentation has an inclined wall 16 a which extends at a downward inclination in flow direction 20 from a middle upper length section of the first heating channel 3 to the outlet opening 7 of the first heating channel 3.
A second, crescent-shaped air entry 17, which is enlarged in the region of the indentation 16, is formed between the perimeter of the outlet opening 7 of the first heating channel 3 and the perimeter of the inlet opening 10 of the second heating channel 4 (FIG. 4).
The deflection channel 5, which initially has a substantially square cross-section and which is increasingly rectangular up to an upwardly directed outlet opening 18 thereof, is hermetically connected with the outlet opening 11 of the second heating channel 4. The deflection channel 5 has an inclined plane 19, which extends obliquely upwardly from the lower middle section of the deflection channel 5 in flow direction 20. An air conveying device 22 is disposed downstream (relative to the flow direction) of the outlet opening 18 of the deflection channel 5. The air conveying device 22 conveys air through the channels in flow direction 20.
Due to the burner head being arranged in the lower section of the first heating channel 3, the guide device 15 in the form of the indentation 16 being provided at the upper end section adjacent to the outlet opening 7 of the first heating channel 3 and the first heating channel being arranged eccentrically in the lower section of the second heating channel 4, the flame or the hot air or hot gases which mixes or mix therewith and which always has or have a tendency to migrate upwardly due to thermal lift and thus excessively heat the upper sections of the first and second heating channel, is or are forced downwardly in each section of the heating configuration or kept in a middle section of the first heating channel 3 or the second heating channel 4. The entire heating configuration, but particularly the first heating channel 3 and the second heating channel 4, is preferably arranged horizontally. However, it is also possible to arrange the heating configuration to extend upwardly at a preferred angle of up to 45° together with the deflection channel 5.
By virtue of the afore-described heating configuration an improved mixing of the gases is achieved, which has the consequence of a more uniform temperature distribution over the flow cross-section. With a more uniform temperature distribution, there is also possible a more precise detection of the temperature of the gases flowing in the heating configuration so that a more exact setting or regulation of the temperature of the gases is possible.
The first supplementary air 14 is fed in a first air stream from behind the burner by way of the first air entry opening 13. Second supplementary air 21 is fed into the heating configuration in a second air stream by way of the second air entry opening 17. This feed of first supplementary air 14 and second supplementary air 21 has the advantage that in the region of the burner only a part of the air quantity required for drying has to flow through the first heating channel 3, so that the burner readily ignites and exhibits good flame formation. Lifting-off of the flame of the burner is thereby prevented and as a consequence combustion noise is avoided. In addition, CO emission and emission of unburned fuel due to the lesser amount of cooling are avoided.
The burner burns with a relatively short and voluminous flame in the first heating channel 3. This leads to good intermixing of the hot exhaust gases with the cold, first supplementary air 14 is produced.
This application claims the priority, under 35 U.S.C. § 119, of German patent application No. 103 32 339.2, filed Jul. 16, 2003; the entire disclosure of the prior application is herewith incorporated by reference.

Claims

1. A heating configuration, comprising:

a burner with a burner head;

a first heating channel having an inlet portion formed with an inlet opening and an outlet portion formed with an outlet opening;

a second heating channel having an inlet portion formed with an inlet opening and an outlet portion formed with an outlet opening;

said second heating channel having a cross-sectional area greater than a cross-sectional area of said first heating channel, said outlet portion of said first heating channel projecting into said inlet portion of said second heating channel, and said burner projecting into said first heating channel through said inlet opening thereof; and

a flow guide in an upper part of said first heating channel adjacent said outlet opening thereof and configured to downwardly deflect a flow of gas flowing in a direction from said burner head towards said outlet opening of said second heating channel.

2. The heating configuration according to claim 1, wherein said burner head is disposed in said first heating channel.

3. The heating configuration according to claim 1, wherein said flow guide comprises an inclined wall extending with a downward slope in the direction from said upper part of said first heating channel between said inlet and outlet openings thereof to said outlet opening of said first heating channel.

4. The heating configuration according to claim 3, wherein said inclined wall is an inwardly deformed portion of a wall of said first heating channel.

5. The heating configuration according to claim 1, wherein said outlet portion of said first heating channel is downwardly offset towards a lower side of said second heating channel.

6. The heating configuration according to claim 1, wherein a part of said burner projecting into said first heating channel is disposed substantially in a lower part of said first heating channel.

7. The heating configuration according to claim 1, wherein a first air entry is formed between a perimeter of said inlet opening of said first heating channel and said burner, and a second air entry is formed between a perimeter of said inlet opening of said second heating channel and a perimeter of an outlet portion of said first heating channel.

8. The heating configuration according to claim 1, which further comprises a deflection channel connected to said outlet opening of said second heating channel and disposed to upwardly deflect gases flowing from said second heating channel.

9. The heating configuration according to claim 8, wherein said deflection channel has an inclined surface extending obliquely upwardly from a lower side of said deflection channel.

10. The heating configuration according to claim 1, which comprises an air conveying device disposed downstream of said outlet opening of said second heating channel with respect to a direction of a flow of gases out of said second heating channel.

11. The heating configuration according to claim 1, wherein said outlet portion of said first heating channel has a base portion connected to a base portion of said inlet portion of said second heating channel.

12. The heating configuration according to claim 1, wherein said burner and said heating channels are configured for assembly in a drier apparatus.

13. In combination with a laundry drier, the heating configuration according to claim 1.