US20170321930A1

US20170321930A1 - Electric heating fan

Info

Publication number: US20170321930A1
Application number: US15/588,815
Authority: US
Inventors: Carsten Hüge; Nadine Fischbach
Original assignee: Stiebel Eltron GmbH and Co KG
Current assignee: Stiebel Eltron GmbH and Co KG
Priority date: 2016-05-09
Filing date: 2017-05-08
Publication date: 2017-11-09
Also published as: DE102016005552A1

Abstract

The invention is directed to a heating fan (100) with an inner space (110) in which is arranged an air channel (810) which is partially made of plastic. An electric heating body (300) is arranged behind a fan (800) in an air flow direction (821). According to the invention, this fan is constructed such that a fan wheel (801) of a radial fan, which fan wheel (801) is contained in the fan (800), has two suction sides (805, 806) which are separated by a dividing wall (804). During operation, a first air flow (822) is sucked in from outside (1) through the first suction side (805) which is open to a first air inlet opening (221). The second suction side (806) is arranged in a fan space (111) of the heating fan (100) and is pneumatically connected to second air inlet openings (222). The fan is arranged in front of a ceramic heating element (301) of the electric heating body (300) so that the first air flow (822) and the second air flow (823) stream through the heating body (300).

Description

RELATED APPLICATIONS

The present application claims priority to German Application No. 102016005552.9 filed on May 9, 2016, the entirety of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention is directed to a heating fan with an inner space in which is arranged an air channel which is at least partially made of plastic. An electric heating body is arranged behind a fan in an air flow direction.

BACKGROUND

Heating fans in which an electric heating body is arranged in an air channel are known commercially. A fan generates an air flow which is blown through the heating body and heated in the heating body. PTC heating bodies are advantageously used in devices which are at least partially made of plastic. For physical reasons, these PTC heating bodies are subject to thermal self-regulation, i.e., they do not overheat in the absence of air flow so that the heating body thermally self-adjusts to a safety temperature.
A heating fan which has a heating body with PTC heating elements which is used in the exhaust air flow of a blower is known from DE 9313789.3. The blower has a blower wheel and is configured as a radial blower. The suction of blower air takes place horizontally via inlet air orifices in the rear side and/or side walls of the heating fan housing with axial in-flow into the blower wheel. The heating fan further has a controller, and the heating register is divided into zones which are formed vertically adjacent to one another so that heating outputs of different magnitudes are possible. Further, an air filter is arranged in the inlet air orifices.

SUMMARY

It is the object of the invention to reduce heating of the plastic parts in correct operation and incorrect operation and to allow a flat construction of the heating fan.
This object is met through the features of claim 1.
The fan has a fan wheel of a radial fan with a first suction side and a second suction side which are separated by a dividing wall. The first suction side is open to a first air inlet opening through which a first air flow is sucked in from the outside through the first suction side during operation. The second suction side is arranged toward a fan space of the heating fan, and the second suction side is pneumatically connected to second air inlet openings. Further, the fan is advantageously arranged in front of a ceramic heating element of the electric heating body so that the first air flow and the second air flow stream through the heating body.
A guide wall through which the fan space is formed is advantageously arranged in the inner space. Accordingly, at least some of the second air flow is guided to the second suction side.
In a preferred configuration, the fan space is situated between the second suction side and the second air inlet opening. During operation of the heating device, air flows out of an inner space into the second suction side.
According to a further aspect of the invention, the fan has an exhaust opening through which a total air flow is guided to the heating body during operation of the heating fan. Further, the heating body is arranged behind the exhaust side in air flow direction.
The second air inlet opening is preferably arranged in the rear wall.
In particular, the first air inlet opening has a larger opening area than the second air inlet opening. The first air inlet opening preferably makes up approximately 55% to 90% of the total opening area of the first and second air inlet openings. Further, the mass flow of the first air flow is greater than the mass flow of the second air flow during operation of the heating fan. The mass flow through the first opening amounts in particular to approximately 60% to 80% of the total mass flow.
In an embodiment example, the fan wheel of the fan has first blades which are arranged toward the first suction side. Further, it has second blades of the fan which are arranged toward the second suction side.
According to the invention, the first blades and the second blades of the fan wheel are separated by a dividing wall.
Finally, it is advantageous that the first blades are larger than the second blades, in particular at least 30% to 70% larger, particularly approximately 50% larger.
A flat construction can advantageously be realized in which the air suction preferably takes place from the rear through a rear wall which is preferably further provided to be connected to a mounting wall. Accordingly, the suction is carried out through the rear wall via a radial blower in which the air flow is deflected by 90°. According to the invention, two air flows are supplied to the radial blower axially from two sides.
The dividing wall is advantageously provided for separating the two air flows. First blades are arranged on one side of the dividing wall, which first blades are preferably larger than second blades on the other side of the dividing wall. The dividing wall is preferably cup-shaped toward the first suction side, a fan motor, particularly with a needle, being arranged in the area of the cup-shaped dividing wall.
Further, the fan motor lies so far inside the fan that it is so-to-speak in the cup, i.e., preferably in the dividing wall, and is surrounded by the first blades. Two suction areas are formed in this way. A more or less direct region through the first air inlet opening and a second region through the second air inlet opening, wherein the air flow through the second air inlet openings is initially sucked through the inner space of the heating fan, and the exhaust heat occurring there, in particular of the heating body, is sucked out through the second air flow.
The inner space of the heating fan, particularly the area between the front and an air channel, is vented through the second air inlet openings even when the heating fan is stationary. Accordingly, the after-heat given off by the heating body is given to a convection flow of air which can stream through the second air inlet openings through the device, particularly from bottom to top. The second air inlet openings serve as inlet openings for the second air flow during operation of the heating fan when the fan motor drives the fan.
Advantageously, the air channel is made of plastic at least partially or in its entirety.
When the device is stationary, a portion of the second air inlet openings advantageously serves as inlet opening for cooling air and another portion of the second air inlet openings serves as outlet opening for the convection air flowing through the device. In stationary state, cool air accordingly flows through the second air inlet openings arranged below in the rear wall in the area of the air outlet into the device. The convection air which is at least slightly heated flows out of the heating fan again in the stationary state through the second air inlet openings which are preferably arranged above the fan in the rear wall of the device.
A controller is spatially separated from the fan by a guide wall. Accordingly, the second air flow is divided into two partial flows, a first partial flow of the second air flow streams past the controller, while a larger, second partial flow of the second air flow flows from the second air inlet openings to the fan. Accordingly, the controller is slightly cooled by a small partial flow so that, in a way, room temperature or air at room temperature flows against it during operation of the heating device.
When the heating device is stationary, an air flow of room air also flows through the second air inlet openings, preferably in the area of the rear wall below in the air outlet grating through the rear wall into the device and flows through the guide wall separately to the controller. Accordingly, the controller is continuously supplied with room air during operation of the heating device and also when the fan is stationary.
Further, at least one or two safety temperature limiters are advantageously provided on the heating body or in the area of the heating body. These safety temperature limiters are outfitted as bang-bang controllers or on-off controllers and/or also advantageously as fuses.
It is particularly advantageous and reliable to form two safety temperature limiters at the PTC heating body, for one, with an on-off controller with a first safety switching temperature and with a fuse with a second safety temperature, where the switching temperature of the on-off controller is advantageously lower than the second safety temperature of the fuse. This causes the heating body to be switched off in case of failure initially of the on-off controller so that a safer condition of the heating fan is achieved. If the on-off controller failed, the heating body would heat the device again and the fuse would blow to prevent overheating.
A fore-grating with air baffles is advantageously provided in the air channel for guiding the air. In this way, the air flow which has formed behind the heating body is deflected a first time. The baffles or guiding devices are preferably arranged substantially horizontally. The air outlet grating which has directed a portion of the air outlet openings toward the bottom and another portion forward in the direction of the front is advantageously arranged behind the first air guiding grating. The guiding surfaces or baffles of the first air guiding grating and air outlet grating are advantageously arranged at an angle to one another to prevent sprayed water from entering.
The heating fan is advantageously outfitted with a device for fastening to a mounting wall. At least the first air flow is advantageously sucked into the heating fan during operation of the fan between the mounting wall, not shown, and the rear wall. The rear wall is accordingly arranged at the mounting wall with the wall fastening, not shown, and therefore also the entire heating fan.
The fan advantageously has a fan wheel of a radial blower, advantageously with a first suction side and a second suction side which are separated by a dividing wall.
According to a further idea, the controller is substantially separated from the fan space by the guide wall.
The common air flow which is conveyed through an air outlet by the blower and which is formed by the first air flow and second air flow is advantageously heated by a ceramic PTC heating element.

BRIEF DESCRIPTION OF DRAWINGS

To the accomplishment of the foregoing and related ends, certain illustrative embodiments of the invention are described herein in connection with the following description and the annexed drawings. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed and the present invention is intended to include all such aspects and their equivalents. Other advantages, embodiments and novel features of the invention may become apparent from the following description of the invention when considered in conjunction with the drawings. The following description, given by way of example, but not intended to limit the invention solely to the specific embodiments described, may best be understood in conjunction with the accompanying drawings, in which:

FIG. 1 shows the heating fan in section;

FIG. 2 shows the heating fan 100 in a sectional three-dimensional view;

FIG. 3 shows a section viewed toward the inner guide wall;

FIG. 4 shows the heating fan with its rear wall and the component parts located in the inner space;

FIG. 5 shows the heating device from the front without its front;

FIG. 6 shows the controller arranged on the inner side.

DETAILED DESCRIPTION

FIG. 1 shows a heating fan 100 arranged in a space 1. An inner space 110 in which an air channel 810 is arranged is located in the heating fan 100. In the embodiment example, the air channel 810 is made of plastic and is configured to guide a hot air flow 820. During operation of the heating fan 100, air is guided in an air flow direction 821 through the heating fan 100 or in air flow direction 821 through the air channel 810. Air flow direction 821 comes about through the operation of a fan 800 which is arranged in front of or in the air channel 810.
The fan 800 has a fan wheel 801 which is driven by a fan motor 830. The fan motor 830 has a hub 831. The fan wheel 801 has two regions. First blades 808 are arranged in the fan wheel in one region and second blades 809 are arranged on another side in another region. The first blades 808 and second blades 809 are separated by a dividing wall 804 of the fan 800.
Accordingly, operation of the heating fan produces a first air flow 822 which is sucked into the heating fan 100 through first air inlet openings 221. The first air flow 822 is generated by the first blades 808 during operation of the fan 800 on the first suction side 805. In the embodiment example, an air filter 860 is advantageously arranged on the first suction side.
A second air flow 823 is generated by the second blades 809 during operation of the fan 800. The second blades 809 which are located on a second suction side 806 suck air from a fan space 111. In the embodiment example, the fan space 111 is located between a front 210 and the second suction side 806 or the second blades 809 of the fan 800. The second air flow 823 is sucked in through second air inlet openings 222 which are arranged in the lower area of a rear wall 220 and in the upper area above a wall spacer 270 in the embodiment example.
A further spacer 270 is arranged below in the heating fan 100 in the rear wall 220 at the level of the air exhaust grating 813 only just toward the rear wall 220. Accordingly, the fan 800 conveys two air volume flows, namely, first air volume flow 822 and second air volume flow 823, during operation, i.e., when the fan motor 830 is supplied with current.
The first air volume flow 822 and the second air volume flow 823 make a total air flow 824 in air flow direction 821 just inside or downstream of the fan 800. This total air flow 824 results at least upstream of a heating block 300 which the total air flow 824 passes during operation of the heating fan 100. Accordingly, the heating block 300 is arranged downstream of the fan 800 viewed in air flow direction 821 and has an electric heating element which is a ceramic heating element 301 in the embodiment example. Therefore, a total air volume flow 824 is generated by the fan 800 and conveyed to the heating block 300 at an exhaust side 807. As is shown in FIG. 1, the fan 800 accordingly sucks a first air flow 822 through a first air outlet opening 221 and a second air flow 823 through second air inlet openings 222 via a fan space 111. The two air flows 822, 823 are then heated by the heating block 300 as total air flow 824 and given off through the air exhaust grating 813 in space 1. In an advantageous manner, the hot air flow 820 is given off obliquely downward into space 1.
Arranged in the air channel 801 upstream of the air exhaust grating 813 is an air deflector 816 which is formed by a plurality of baffles 817 arranged horizontally in the embodiment example. In the embodiment example according to FIG. 1, the air deflector 816 comprises baffles 817 which are made of plastic and which also have an angle 818 of approximately 110°.
According to FIG. 2, the heating fan 100 is shown with a suction grating 812 which is arranged toward the first blades 808 in air flow direction 821 during operation of the fan 800. The air suction grating 812 is located on the first suction side 805.
An air filter holder 861 is advantageously provided in the embodiment example. A lint filter, not shown, or a filter is inserted therein. Accordingly, the first air flow 822 which is generated by the first blades 808 is cleaned through filters and/or guided through an air suction grating 812.
Further, in the embodiment example the heating fan 100 has a cable space 290 in which a connection cable, not shown, can be wound up or stowed. Accordingly, the cable space 290 is located in the area of the air channel 810. The cable is advantageously connected to a socket terminal strip 710.
Further, the heating fan 100 has an operator control part 401 with which a controller 400 can be adjusted. A target temperature for space 1 can be set with the controller 400. In an advantageous manner and for precise control, air is supplied to the controller 400 which is arranged in the inner space 110, which takes place through the second air inlet openings 222 in the embodiment example. During operation of the device, air is sucked in through all second air inlet openings 222, flows past the controller 400 at least partially and provides the controller 400 with air from space 1. When the heating fan 100 is stationary, the controller 400 is ventilated with air from space 1 through the second air inlet openings 222 which are situated below and which are arranged in the area of cable space 290. The air flows through convection from the bottom, i.e., the second air inlet openings 222 arranged in the area of the cable 290, to the controller where it passes out of the device again in the vicinity of the controller 400 through the second air inlet openings 222 arranged at the top.
Therefore, the function of the second air inlet openings 222 changes when the heating fan 100 is stationary. In this case, air flows out of the heating fan 100, whereas during operation of the heating fan 100 it flows through the second air inlet openings 222 arranged at the top of the controller 400 into the device toward the second suction side 806.
Further, a guide wall 112 is arranged at the air channel 810 for at least partially separating the convection air flow to the controller 100 from air channel 810 when the heating fan 100 is stationary. The basis for this step consists in that the air channel 810 and the area of the heating block 300 are warm during operation of the heating fan 100 and this heat is given off as after-heat when the device is stationary. The controller is to be substantially spared from this after-heat. However, a certain proportion of after-heat serves to correctly switch off the heating fan and is advantageous for temperature control. Accordingly, the guide wall 112 is arranged between the air channel 810 and a front inner side 211 in the embodiment example. There is a small gap 113 between the guide wall 112 and the front inner side 211. The gap 113 advantageously serves to prevent vibrations from being transmitted from the air channel to the front 210 and deformation in the front 210 due to pressing out of the guide wall 112. The guide wall 112 substantially follows a side of the air channel 810. This one side of the air channel 810 is extended farther and terminates with a gap 113 relative to the forward front inner side 211.
The heating block 300 is thermally safeguarded by a safety temperature limiter 430 and sits on the heating block 300. Further, a fuse 431 is provided for additional security. The safety temperature limiter 430 has a lower shut-off temperature than the fuse 431. The safety temperature limiter 430 which is configured as PTC element responds first. After eliminating a possible error, the safety temperature limiter 430 resets and the heating fan 100 can be operated again. The fuse 431, which is provided with a higher shut-off temperature, responds when a temperature in the heating device exceeds the shut-off temperature of the safety temperature limiter 430. An additional thermal safeguarding of the heating fan 100 is achieved in this way. The heating block 300 is advantageously outfitted with a self-regulating heating element, particularly with self-regulating ceramic heating elements 301, which reduces the heating output with increasing temperature. Therefore, the heating block 300 in the embodiment example is inherently safe.
The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Although illustrative embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope and spirit of the invention as defined by the appended claims.

Claims

1. A heating fan with an inner space having an air channel, comprising:

an electric heating body arranged behind a fan in an air flow direction,

wherein the fan has a fan wheel of a radial fan with a first suction side and a second suction side which are separated by a dividing wall,

wherein the first suction side is open to a first air inlet opening through which a first air flow is sucked in from outside through the first suction side during operation,

wherein the second suction side is arranged in a fan space of the heating fan, and the second suction side is pneumatically connected to second air inlet openings, and the fan is arranged in front of the electric heating body so that the first air flow and the second air flow stream through the heating body.

2. The heating fan according to claim 1, wherein a guide wall through which the fan space is formed is arranged in the inner space so that at least some of the second air flow is guided to the second suction side.

3. The heating fan according to claim 1, wherein the fan space is situated between the second suction side and the second air inlet opening so that air flows out of an inner space into the second suction side during operation of the heating device.

4. The heating fan according to claim 1, wherein the fan has an exhaust opening through which a total air flow is guided to the heating body during operation of the heating fan, and the heating body is arranged behind the exhaust side in air flow direction.

5. The heating fan according to claim 1, wherein the second air inlet opening is arranged in the rear wall.

6. The heating fan according to claim 1, wherein the first air inlet opening has a larger opening area than the second air inlet opening, wherein the first air inlet opening makes up in particular approximately 55% to 90% of the total opening area of first air inlet opening and second air inlet opening so that the mass flow of the first air flow is greater than the mass flow of the second air flow during operation of the heating fan, and the mass flow through the first opening amounts in particular to approximately 60% to 80% of the total mass flow.

7. The heating fan according to claim 1, wherein the fan wheel of the fan has first blades which are arranged toward the first suction side, and in that second blades of the fan are arranged toward the second suction side.

8. The heating fan according to claim 1, wherein the first blades and the second blades of the fan wheel are separated by a dividing wall.

9. The heating fan according to claim 1, wherein the first blades are larger than the second blades, in particular at least approximately 50% larger.

10. The heating fan according to claim 1, wherein the electric heating body is a ceramic heating element.