EP4339466A1 - Heater with blower - Google Patents

Abstract

The invention relates to a heater (1) with a fan (2) comprising a fan wheel (18) which can be rotated about an axis of rotation (22) and a housing (6) comprising at least a first housing part (14) and a second housing part (15). , which can be assembled in the direction of the axis of rotation (22) with the inclusion of a sealing arrangement (23), the sealing arrangement (23) being designed to maintain the sealing effect even when there is a deformation distance (25) in the direction of the axis of rotation (22) between the first housing part (14) and the second housing part (15) at least partially maintained.

Description

The invention relates to a heating device.

Heaters usually have a conveyor device that is designed to transport a volume flow of combustion air or a mixture of combustion air and fuel to a burner of the heater. The conveying devices are often designed as fans and are arranged in a mixture channel of the heater.

When operating a heater, especially during ignition processes, flashbacks can occur. A flashback indicates that the flame spreads against the gas flow in the heater into the mixture channel and possibly also into a fan arranged there. Deflagrations that occur can damage the fan, in particular this can result in leaks from the housing to the environment or the housing of the heater.

A leak on the suction side of a conveyor device can lead to a gas exchange between the mixture channel and the environment, whereby external air enters the mixture channel and causes a shift in the air ratio (combustion air ratio, lambda) of the fuel-air mixture to be supplied to the burner, which can lead to critical operating states of the heater. A leak on the pressure side of the conveyor device can lead to unburned fuel escaping, which poses a risk of explosion.

Various options are known from the prior art for avoiding flashbacks in heating devices. For example in the EP 3 875 854 A1 It is proposed to form a mixture flow path with a length that corresponds to 9 to 11 times the detonation cell size. This makes it possible to achieve particularly stable combustion on the burner and prevent the flame from lifting off the burner surface and backfiring into the mixture channel.

The EP 3 988 841 A1 discloses a method and a device for preventing a flashback comprising a first component which is arranged such that its temperature is influenced by the combustion and expands as a function of the temperature. The expansion can be recorded by a sensor. The invention is intended to make it possible to identify situations that can lead to flashbacks at an early stage and to initiate countermeasures.

However, the solutions mentioned cannot sufficiently or even completely prevent the occurrence of flashbacks and the associated damage to the heater and fan.

Based on this, it is the object of the invention to propose a heating device that at least partially overcomes the problems described in the prior art. In particular, the invention is intended to enable continued operation of the heater after a flashback and to reduce the damaging effects of a flashback.

In addition, the invention should at least not significantly increase the complexity of a heater and only require minor structural changes.

These tasks are solved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It should be noted that the features listed in the dependent patent claims can be combined with one another in any technologically sensible manner and define further embodiments of the invention. In addition, the features specified in the patent claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

A heater contributes to this, having a fan which has at least one fan wheel that can be rotated about an axis of rotation and a housing. The housing comprises at least a first housing part and a second housing part, which can be assembled (or already assembled) in the direction of the axis of rotation with the inclusion of at least one sealing arrangement. The sealing arrangement is designed to at least partially, predominantly or even completely maintain the sealing effect even when there is a deformation distance in the direction of the axis of rotation between the first housing part and the second housing part.

The heater can be a heater (possibly stationary on or in a building) which includes at least one burner to which a mixture of combustion air and a fuel can be supplied. The heater can in particular be a gas heater, designed to burn a gaseous fuel, in particular hydrogen or a gas mixture containing hydrogen, with the supply of fresh air (ambient air) as combustion air, and thus to provide heat for the heating circuit. The heater can have at least one burner and one as a fan trained, conveyor device that conveys a mixture of fuel (gas) and combustion air through a mixture channel of the heater to the burner. The combustion products can then be led to an exhaust system, which can include an exhaust duct internal to the heater.

The blower can be a blower suitable for providing a combustion air flow or a volume flow of a mixture of fuel gas and combustion air, for example a radial or axial fan. In particular, the fan can be a centrifugal fan.

Centrifugal fans usually have a radial impeller as a fan wheel and can suck in a fluid (air) from a direction parallel to a rotation axis of the fan wheel and blow it out in a radial direction. For this purpose, radial fans often have a housing in which the radial impeller is mounted and on which a drive device (electric motor) can be arranged to drive the radial impeller. The housing is generally designed in several parts, in particular in two parts, with two housing parts being able to be assembled in the axial direction. The first housing part is often a motor plate on which the drive motor can be attached. The second housing part can in particular house the impeller.

According to the prior art, a sealing arrangement is generally implemented by a groove in the second housing part for receiving a seal and a corresponding sealing surface on the first housing part. The seal can be a sealing ring made of an elastic material (elastomer, rubber). It was found that one... sudden increase in pressure as part of an ignition flashback can form a deformation distance between the first and second housing parts. The term “deformation distance” refers in particular to a distance or a gap between the two housing parts in the area of the sealing arrangement (if necessary only) during a pressure-related deformation of the housing, in particular in the event of an ignition kickback. The sealing ring can emerge from the groove and, possibly supported by the pressure built up by the impeller in the housing, move into the deformation distance between the first and second housing parts, or can also exit completely from the space between the first and second housing parts. As a result, the housing has a significant leak, through which the mixture of fuel and combustion air to be conveyed can escape and lead to deflagration or flame formation outside the housing of the blower.

According to one idea of the invention, the sealing arrangement between the first and second housing parts is designed in such a way that a deformation distance that forms, for example in the context of a flame flashback and the associated sudden increase in pressure in the housing of the blower, as axial relative movements of the housing parts to one another, at least with partial preservation of the Sealing effect can be compensated.

In the context of this disclosure, the indication of a sealing surface “axially relative to the axis of rotation of the blower” means that a normal vector of the sealing surface is (largely) aligned in the direction of an axis of rotation of the blower. Accordingly, the specification of a sealing surface “radially relative to the axis of rotation” means that a normal vector of the sealing surface is aligned radially.

The deformation distance characterizes in particular a (possibly short-term and/or reversible) relative movement from the first housing part to the second housing part, which can occur in the event of a flashback. The deformation distance can be determined for a reference fan in a reference heater experimentally or by evaluating recorded real damage patterns. The deformation distance can be influenced by a variety of factors, in particular the burner output, the design of the housing of the blower (wall thickness of the housing and the number and/or the distance of connection points between the first and second housing parts). A required deformation distance can be determined through a pressure test or simulation calculations. For this purpose, the maximum pressure that occurs in the heater to be designed in the event of a flashback should be known.

A deformation distance in the range of 1 mm [millimeters] to 3 mm can prevent leakage due to flashback in many heaters. A deformation distance in the range of 1 mm to 2 mm can often be sufficient.

The sealing arrangement can have a sealing surface which is aligned axially with respect to the shaft or axially with respect to the axis of rotation of the impeller. It can be arranged as a sealing ring in a recessed groove. The recessed groove can have a depth that is greater than the extension of the seal in the direction of the rotation axis of the fan by at least the deformation distance. In addition, a rib can engage in the recessed groove and create a sealing connection to the seal, and thus to the first and second housing parts. Due to the recessed groove and in conjunction with at least one rib engaging in the recessed groove, it can be effectively prevented that the seal can emerge from the recessed groove due to a deformation distance that occurs.

The recessed groove can (only) be arranged in the second housing part surrounding the impeller and the circumferential rib can be provided on the first housing part. In particular, if the first housing part is designed as an at least partially flat plate for arranging the drive motor, the circumferential rib can stiffen the first housing part. This advantageous synergy effect causes a reduction in the deformation distance because a flat deformation (e.g. in the manner of a bulging) of the first housing part can be prevented.

The at least one rib can (also) be designed to be resilient and designed to compensate for an occurring deformation distance by a spring movement in its direction. The spring movement can maintain contact between the seal and the sealing surface of the rib, and thus the sealing effect of the sealing arrangement.

The sealing arrangement can have a sealing surface which is aligned radially with respect to the axis of rotation of the blower, the seal being arranged in a groove of the first housing part and the corresponding sealing surface of the second housing part having an axial width which corresponds at least to the deformation distance. When a deformation distance occurs, the sealing surface can move in the axial direction relative to the sealing ring, with the sealing surface remaining in contact with the seal due to its axial width without losing the sealing effect.

The sealing arrangement may have a sealing surface which is axially aligned with respect to the axis of rotation of the blower, the seal also being arranged in the radial direction between the first and second housing parts. The seal can be in one Groove may be arranged, with one side of the groove forming the first housing part and the (opposite) second side of the groove forming the second housing part. In particular, the first housing part can form the radially outer side of the groove, whereby the seal can be prevented from being pushed out of a space between the first and second housing parts due to a gas flow or a pressure difference when a deformation distance occurs.

The heater can in particular be a hydrogen-powered gas heater.

According to one embodiment, the fan of the heater can be arranged in a mixture channel of the same.

As a precaution, it should be noted that the number words used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, sizes or processes, i.e. in particular no dependency and/or order of these objects, sizes or prescribe processes to each other. If a dependency and/or sequence is required, this is explicitly stated here or it will be obvious to the person skilled in the art when studying the specifically described embodiment. To the extent that a component can occur multiple times ("at least one"), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

A heater is therefore specified here which at least partially solves the problems described with reference to the prior art. In particular, the heater is wearing at least helps to increase the resistance of a fan to flashbacks and thus avoid decommissioning and repairs to a heater.

In addition, the invention can be implemented particularly easily, since only minor structural changes are necessary to a housing of a blower.

Fig. 1:

ein hier vorgeschlagenes Gebläse für ein Heizgerät,

Fig. 2

ein hier vorgeschlagenes Heizgerät, und

Fig. 3 bis Fig. 7

Ausgestaltungen einer Dichtungsanordnung eines hier vorgeschlagenen Gebläses.

The invention and the technical environment are explained in more detail below using the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments given. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures and in particular the proportions shown are only schematic. Show it:

Fig. 1:

a fan suggested here for a heater,

Fig. 2

a heater proposed here, and

Fig. 3 to Fig. 7

Refinements of a sealing arrangement of a blower proposed here.

Fig. 1 shows an example and schematically of a fan 2. This can include a housing 6 with a first housing part 14 and a second housing part 15, which can be assembled in a direction of an axis of rotation 22 of the fan wheel 18. The second housing part 15 can (essentially or alone) enclose the impeller 18 or surround it in the circumferential direction. The impeller 18 can be arranged rotatably mounted inside the housing 6 in a direction of rotation 19 about the axis of rotation 22 and can be connected axially via a shaft 24 to an electric motor 17. The electric motor 17 can be arranged on the first housing part 14, which can also be referred to as a motor plate. The shaft 24 can be guided in a sealed manner through the first housing part 14 and drive the impeller 18. The blower 2 can suck in a gas stream via an inlet 11 in an inlet direction 21, which can correspond to an axis of rotation 22 of the blower 1, and eject it in an outlet direction 20.

A sealing arrangement 23 can create a sealing connection all around between the first housing part 14 and the second housing part 15.

Fig. 2 shows an example and schematic of a (stationary) heater 1 proposed here. This receives combustion air via a supply of combustion air 4 by means of a blower 2 and via a gas valve 5 a fuel gas, for example hydrogen, which is added to the volume flow of combustion air. The combustion mixture of gas and combustion air can now be fed via a mixture channel 16 to a burner 3 arranged in a combustion chamber 8. The combustion chamber 8 can include one or more heat exchangers, which can transfer the heat generated during the combustion process to a heat transfer medium circulating in a heating circuit. The combustion products can be fed from the combustion chamber 8 to an exhaust system 10 via an exhaust pipe 9. A UV sensor 13 for flame monitoring can, Protected from the high temperatures in the combustion chamber 8, be arranged on the outside of the combustion chamber 8. The heater 1 can also have a control and control device 7.

Fig. 3 shows, by way of example and schematically, a sealing arrangement 23 of the fan 2. A recessed groove 29 for receiving a seal 26, which can be designed as a sealing ring, has a predetermined depth 32. The depth 32 of the recessed groove 29 can be (at least) the sum of (expected or predetermined) deformation distance 25 and the extension of the seal 26 in the direction of the axis of rotation 22. A rib 28 formed on the first housing part 14 can have at least one extension in the direction of the axis of rotation 22 corresponding to the deformation distance 25 and can engage in the recessed groove 29, so that an axially (relative to the axis of rotation 22) aligned sealing surface 30 on the seal 26 applied.

Fig. 4 shows the sealing arrangement 23 Fig. 3 after the occurrence of a deformation distance 25, for example triggered by a flashback and an associated increase in pressure in the housing 6 of the blower 2. The rib 28 has partially emerged from the recessed groove 29, but can hold it in the groove 29, so that a (desired ) limited sealing effect can be maintained.

Fig. 5 shows an embodiment of the seal 26 with a sealing lip 27, which can offer tolerance compensation, particularly in conjunction with a radially aligned sealing surface 31, and which can improve the maintenance of the sealing effect when a deformation distance 25 occurs.

Fig. 6 shows an embodiment of the sealing arrangement 23 with a radially aligned sealing surface 31 on the first housing part 14. When a deformation distance 25 occurs in the direction of the axis of rotation 22, the seal 26 remains in contact with the radially aligned sealing surface 31 and thus the sealing effect can be maintained even when a deformation distance 25 occurs remain. For this purpose, the radially aligned sealing surface 31 can have an axial width 12 that is greater than the deformation distance 25.

Fig. 7 shows a further embodiment of the sealing arrangement 23. This can include an axially aligned sealing surface 30. The seal 26 can also be arranged in the radial direction between the first housing part 14 and the second housing part 15. Here, the seal 26 can be understood as being arranged in a groove 29, wherein a side wall of the groove 29 can be formed by the first housing part 14 and the other side of the groove 29 can be formed by the second housing part 15. The first housing part 14 can in particular form the radially outer lateral (radial) boundary of the seal 26, whereby a pushing out of the seal 26 from a space between the first housing part 14 and the second housing part 15 due to a gas flow or a pressure difference when a deformation distance 25 occurs can be avoided .

Reference symbol list

1

heater

2

fan

3

burner

4

Supply of combustion air

5

Gas valve

6

Housing

7

Control and control device

8th

combustion chamber

9

exhaust pipe

10

Exhaust system

11

inlet

12

axial width

13

UV sensor

14

first housing part

15

second housing part

16

Mixture channel

17

Electric motor

18

impeller

19

Direction of rotation

20

Exhaust direction

21

Inlet direction

22

Axis of rotation

23

Sealing arrangement

24

Wave

25

Deformation distance

26

poetry

27

sealing lip

28

rib

29

(deepened) groove

30

axially aligned sealing surface

31

radially aligned sealing surface

32

depth (groove)

Claims (8)

Heater (1) with a fan (2), having a fan wheel (18) rotatable about an axis of rotation (22) and a housing (6), comprising at least a first housing part (14) and a second housing part (15), which can be assembled in the direction of the axis of rotation (22) with the inclusion of a sealing arrangement (23), the sealing arrangement (23) being designed to ensure the sealing effect even when there is a deformation distance (25) in the direction of the axis of rotation (22) between the first housing part (14). and second housing part (15) at least partially maintained. Heater (1) according to claim 1, wherein the sealing arrangement (23) has a sealing surface (30) which is axially aligned with the axis of rotation (22) and a seal (26) is arranged in a recessed groove (29), the recessed groove (29) has a depth (32) which is greater than an extension of the seal (26) in the direction of the axis of rotation (22) by at least the deformation distance (25) and at least one rib (28) in the recessed groove (29 ) engages and rests on the seal (26). Heater (1) according to claim 2, wherein the rib (28) is arranged on the first housing part (14) and is designed to mechanically stiffen the first housing part (14). Heater (1) according to claim 1 or 2, wherein the rib (28) is designed to be resilient in the direction of the axially aligned sealing surface (30) and is designed to compensate for the deformation distance (25) by a spring movement. Heater (1) according to claim 1, wherein the sealing arrangement (23) has a sealing surface (31) which is aligned radially with respect to the axis of rotation (22), with a seal (26) in a groove (29) of the first housing part (14 ) is arranged and a corresponding sealing surface (31) of the second housing part (15) has an axial width (12) which corresponds at least to the deformation distance (25). Heater (1) according to claim 1, wherein the sealing arrangement (23) has a sealing surface (30) which is axially aligned with respect to the axis of rotation (22), the seal (26) also being in the radial direction between the first housing part (14) and second housing part (15) is arranged. Heater (1) according to one of the preceding claims, wherein the sealing arrangement (23) comprises a sealing lip (27) which projects resiliently in the direction of the sealing surface (30, 31). Heater (1) according to one of the preceding claims, wherein the fan (2) is arranged in a mixture channel (16) of the heater (1).

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