GB2551040A

GB2551040A - Flue-Pipe Fan

Info

Publication number: GB2551040A
Application number: GB1707495.6A
Authority: GB
Inventors: Sizeland Robert
Original assignee: Valiant Stoves Ltd
Current assignee: Valiant Stoves Ltd
Priority date: 2017-05-10
Filing date: 2017-05-10
Publication date: 2017-12-06
Anticipated expiration: 2037-05-10
Also published as: GB201707495D0; WO2018206914A1; CN108131307A; GB2551040B

Abstract

A flue-pipe fan 10 comprises a pipe-mountable body 12 with a mounting element 14 on the pipe-mountable body 12, a thermoelectric motor (16, Fig. 3) supported by the mounting element 14, and a fan blade (20, Fig. 2) driven by the thermoelectric motor (16, Fig. 3). The pipe-mountable body 12 has an arcuate pipe-facing surface 18 and an engagement element 30 releasably holds the pipe-mountable body 12 to a flue pipe. The engagement element 30 may be magnetic. The pipe mountable body 12 may comprise a curved body member 22 with portions 26 to receive the engagement element 30. The mounting element 14 may comprise a mounting connector (54, Fig. 5) and a perpendicular platform element (52, Fig. 5). The thermoelectric motor (16, Fig. 3) may be mounted on a heat exchanger 34 which is mounted on the mounting element 14. A stove, a flue-pipe fan mounting apparatus, and a method of mounting a flue-pipe fan 10 to a flue pipe of a stove are also claimed.

Description

Flue-Pipe Fan

The present invention relates to a flue-pipe fan, particularly but not necessarily exclusively for a wood burning stove. The invention further relates to a stove apparatus including a flue-pipe fan.

Wood burning stoves and similar solid fuel stoves are becoming increasingly popular, particularly with a growing consensus towards the use of sustainable fuel sources. Stove-top thermally-powered fans are used to distribute heat from the stove more efficiently within a room in which the stove is installed, and these fans are generally mounted to a flat top surface of the stove.

The fans incorporate a thermoelectric motor, which utilises temperature differentials to create an electrical voltage, which can in turn power the rotation of a fan blade. The body of a thermoelectric motor is typically formed as a finned or fanned metallic element, the base of which is in direct contact with the stove. As such, there will be a significant temperature gradient between the top of the body and the base, which generates the thermoelectric effect.

One problem of such thermoelectric fans is that users often position them too close to the flue of the stove, which heats the top of the body and negates the thermoelectric effect. This can also cause damage to the fan body, as the fan is not designed to be heated in such a manner. Notwithstanding the radiative heating effect of the flue which inhibits the operation of the fan, it is not possible to mount fans to flues, as one cannot drill into a flue for safety reasons, since this will create exhaust gas escape pathways.

Other problems are that modem stoves are now often coated or otherwise covered, for example with marble or soapstone tops, which limit thermal conduction through the top of the stone. This prevents the operation of stove-top fans. Furthermore, the fans are typically freely positioned on a stove-top, which allows the fan to be easily knocked over. Thermoelectric motors are quite delicate, and prone to break if falling from a stove height.

The present invention seeks to provide a flue-pipe fan which hmits or obviates the above-mentioned problems.

According to a first aspect of the invention, there is provided a flue-pipe fan comprising a pipe-mountable body, a mounting element on the pipe-mountable body, a thermoelectric motor directly or indirectly supported by the mounting element, and a fan blade drivable by the thermoelectric motor, the pipe-mountable body having an at least in part arcuate pipe-facing surface and at least one engagement element, preferably being a magnetic element, for releasably holding the pipe-mountable body to a flue pipe.

By attaching the fan to a flue pipe, there is less danger of the fan being knocked over, causing damage to the thermoelectric motor, whilst the pipe-mountable body and mounting element provide a buffer between the thermoelectric motor and the flue pipe which allows for normal operation of the motor. The magnetic attachment of the fan to the flue also removes the dangers associated with drilling of the flue pipe.

Preferably, the pipe-mountable body may comprise an arcuate body member which defines the arcuate pipe-facing surface and which is at least in part receivable around an outer surface of a flue pipe. Said arcuate body member may comprise at least one receiving portion within which the at least one magnetic element is receivable, in which case, the at least one receiving portion may be positioned on the arcuate pipe-facing surface of the arcuate body member. A plurality of said receiving portions may be provided, the receiving portions being symmetrically spaced along the arcuate body member.

The arrangement of the pipe-mountable body is configured so as to improve the ease and security of the attachment of the fan to the flue pipe, which minimises the risk of accidental ejection of the fan from the flue pipe.

Optionally, the mounting element may comprise a platform element and a mounting connector which is connected to the platform element, the mounting connector being connectable to the pipe-mountable body such that the platform element in use is or is substantially in a plane perpendicular to a longitudinal axis of a flue pipe. The platform element may be or substantially be perpendicular to the mounting connector. The pipe-mountable body may include a mounting channel with which the mounting connector of the mounting element is engagable. Furthermore, the mounting connector may include at least one spacing ridge for in use spacing the thermoelectric motor from the pipe-mountable body, and the at least one spacing ridge may be formed from a thermal insulator. In one embodiment, the mounting platform may include a recess with which the thermoelectric motor is positively engagable.

The mounting element is formed so as to provide a radiative buffer between the flue pipe and the thermoelectric motor, whilst still maintaining the thermal link to the base of the motor to enable the thermoelectric effect to work efficiently.

Preferably, the or each magnetic element may comprise a samarium cobalt magnet.

Flue pipes can reach temperatures up to around 300 degrees Celsius, and therefore it is advisable to utilise high-temperature performance magnets as the or each magnetic element, in order to prevent unintentional demagnetisation of the magnets.

Preferably, the fan further comprises a heat exchanger to which the thermoelectric motor is mounted, the heat exchanger being mounted to the mounting element. The pipe-mountable body and mounting element may preferably be formed from a thermally-conductive material, the pipe-mountable body and mounting element forming a thermal conduction path from the pipe-mountable body to a base of the heat exchanger. Furthermore, a height of the heat exchanger may be less than or equal to that of the mounting element, such that, in use, the mounting element acts as a radiative thermal break between a flue pipe and the heat exchanger.

Thermal contact between the flue pipe and the base of a heat exchanger associated with the thermoelectric motor is important, as is the maintenance of a temperature differential across the height of the heat exchanger. The particular arrangement of the pipe-mountable body and mounting element beneficially serves to provide these features.

In one embodiment, the pipe-mountable body may include a main body member and at least one adjustable side member, the or each adjustable side member being moveable relative to the main body member to alter a dimension of the arcuate pipe-facing surface. The at least one engagement element may conveniently be mounted in or on the or each adjustable side member. Furthermore, the or each adjustable side member may be hingeably engagable with the main body member.

The provision of an adjustable pipe-mountable body allows for a single flue-pipe fan to be used in conjunction with different flue pipes of different diameters

According to a second aspect of the invention, there is provided a stove apparatus comprising a stove; a flue pipe connected to the stove for directing exhaust gases from the stove; and a flue-pipe fan preferably in accordance with the first aspect of the invention, the pipe-mountable body of the flue-pipe fan being directly mounted to the flue pipe.

According to a third aspect of the invention, there is provided a flue-pipe fan mounting apparatus comprising a pipe-mountable body, a mounting element on the pipe-mountable body via which a thermoelectric motor may be directly or indirectly supported, the pipe-mountable body having an arcuate pipe-facing surface and at least one engagement element for releasably holding the pipe-mountable body to a flue pipe.

According to a fourth aspect of the invention, there is provided a method of mounting a flue-pipe fan to a flue pipe of a stove, the method comprising the steps of: a] providing a flue-pipe fan preferably in accordance with the first aspect of the invention; and b] engaging the arcuate pipe-facing surface to a flue pipe using the at least one magnetic element such that a temperature gradient can be formed at or adjacent to the mounting element to power the thermoelectric motor.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a perspective representation of a first embodiment of a flue-pipe fan in accordance with the first aspect of the invention, with the thermoelectric motor and fan blade removed for ease;

Figure 2 shows a front view of the heat exchanger, thermoelectric motor and fan blade of the flue-pipe fan of Figure 1;

Figure 3 shows a side view of the heat exchanger, thermoelectric motor and fan blade of Figure 4;

Figure 4 shows a perspective representation of the pipe-mountable body of the flue-pipe fan of Figure 1;

Figure 5 shows a perspective representation of the mounting element of the flue-pipe fan of Figure 1;

Figure 6 shows a front view of a second embodiment of a heat exchanger, thermoelectric motor and fan blade of a flue-pipe fan in accordance with the first aspect of the invention;

Figure 7a shows a perspective representation of a second embodiment of a pipe-mountable body for use as part of a flue-pipe fan in accordance with the first aspect of the invention, in a closed condition; and

Figure 7b shows a perspective representation of the pipe-mountable body of Figure 7a, in an open condition.

Referring to Figure 1, there is shown a flue-pipe fan, indicated globally at 10, for attachment to a flue pipe of a stove. A thermoelectric motor and fan blade of the flue-pipe fan 10 are omitted from Figure 1, although these features can be seen in Figures 2 and 3.

The flue-pipe-fan 10 comprises a pipe-mountable body 12 and a mounting element 14, to which a thermoelectric motor 16 is directly or indirectly mountable. The pipe-mountable body 12 is formed so as to have an arcuate pipe-facing surface 18 which is engagable, preferably complementarily engagable, with the outer surface of a flue pipe. The thermoelectric motor 16 is provided so as to be coupled to a fan blade 20. In this embodiment, a four-bladed fan blade 20 is provided.

In the present context, a thermoelectric motor utilises a temperature differential in order to generate electrical power. Such a motor may be provided as a solid-state device which converts heat flux into electrical energy via the Seebeck effect. Bismuth alloys. particularly tellurides, lead allows, and silicon germanium alloys are examples of thermoelectric materials.

In the present embodiment, the pipe-mountable body 12 has a curved body member 22 which defines the arcuate pipe-facing surface 18 as a portion of the surface of a cylinder, having a uniform radius. The pipe-mountable body 12 may also have an arcuate outward surface 24 which is in use distal to the flue pipe, which may serve to minimize or reduce the weight of the pipe-mountable-body 12.

At least one, and preferably a plurality of, receiving portions 26 may be provided, preferably formed in the arcuate pipe-facing surface 18, although it will be appreciated that such receiving portions could be formed inside the pipe-mountable body 12 or on the outward surface 24, depending on the complexity of manufacture of the flue-pipe fan 10. Each receiving portion 26 may preferably be formed as an elongate groove which spans an axial, that is, an in use axial direction of the flue pipe, extent of the arcuate pipe-facing surface 18. Preferably, the receiving portions 26 may be symmetrically spaced and/or positioned about a circumference defined by the curved body member 22.

The curved body member 22, where receiving portions 26 are provided on the arcuate pipe-facing surface 18, may be provided with at least one reinforcing element 28 which is positioned on the outward surface 24 opposite the receiving portions 26. Such a reinforcing element 28 may add rigidity or structural support to the curved body member 22 in order to provide a connection means inside each receiving portion 26.

The receiving portions 26 are sized and shaped so as to receive and securely hold a magnetic element 30 therein. Preferably, a single magnetic element 30 is provided to snugly fit in each respective receiving portion 26, and is formed from a permanent magnetic material which is resistant to high temperatures. Samarium cobalt magnets are suitable for this purpose, but other high temperature magnets are available which will not demagnetise at the temperatures typically produced at a flue pipe.

Although a magnetic element is preferred, since it is robust, reliable and simple to operate, other suitable engagement elements may be considered, such as a strap or band which encircles the mounting pipe. The engagement element utilised is preferably not insertable into the pipe, due to potential hazardous gas leakage from any opening that is formed.

Each magnetic element 30 is provided so as to be secured in place, preferably via a fastener 32 such as a screw-threaded fastener which is complementarily engagable with a corresponding receiving thread in the pipe-mountable body 12. This can be seen in Figure 4. It will be appreciated, however, that the magnetic elements 30 could be held captive in their respective receiving portions 26 without a dedicated fastener, for example, by shaping the magnetic elements 30 and receiving portions 26 to form an interference fit such as a wedge.

The arc of the arcuate pipe-facing surface 18 of the pipe-mountable body 12 may be maintained by shaping of the magnetic elements 30. A pipe-facing surface of each magnetic element 30 may be formed to have a corresponding curvature to the arcuate pipe-facing surface 18, thereby allowing the magnetic elements 30 to sit flush or substantially flush to the flue pipe in use so as to improve magnetic contact therebetween.

The thermoelectric motor 16 is preferably mounted to a heat exchanger 34 which is formed from a thermally conductive material, such as steel or aluminium, for example. The heat exchanger 34 of the present embodiment has a base portion 36 which is formed as a flat plate 38 having a lower mounting surface 40. A pair of supports 42 are provided which divergently extend from the stem 40, and which support a plurality of, preferably arcuate, radiator fins 44. A mounting area 46 may be formed between the pair of supports 42 within which the thermoelectric motor 16 is mountable. This can be seen in Figures 1 to 3.

An output shaft 48 of the thermoelectric motor 16 may be provided so as to project from a front face of the heat exchanger 34, thereby permitting the fan blade 20 free space in which to rotate. A coupling wiring arrangement 50 may then extend out from the rear of the heat exchanger 16. The coupling wiring arrangement 50 can be engaged with the heat exchanger 16 so as to make use of the in use temperature differential which will be produced across the height of the heat exchanger 34.

The mounting element 14 is formed so as to act as a support or stand for the heat exchanger 34. It will, however, be appreciated that the mounting element 14 could be formed so as to act as the heat exchanger 34, if desired. The mounting element 14 is shown in detail in Figure 5.

The mounting element 14 here includes a platform element 52 and a mounting connector 54. The platform element 52 is a support upon which the heat exchanger 34 can be mounted, and a recess 56 may be provided which positively accepts the base portion 36 of the heat exchanger 34. Additionally, or alternatively, a securing fastener may be provided via which the heat exchanger 34 can be engaged with the mounting element 14 to more securely fasten the thermoelectric motor 16 in position.

The mounting connector 54 allows the mounting element 14 to be coupled to the pipe-mountable body 12. This may be provided as an elongate arm 58 which extends perpendicularly from the mounting platform 52, or substantially so, and includes a coupling means to permit engagement of the mounting element 14 to the pipe-mountable body 12. In this instance, the pipe-mountable body 12 includes a mounting channel 60 with which the mounting connector 54 of the mounting element 14 is engagable, preferably positioned on the outward side 24 of the curved body member 22. One or more fasteners 62 may then be provided with which the mounting connector 54 is connectable to the pipe-mountable body 12. The mounting channel 60 is preferably formed so as to snugly engage with an axial extent of the elongate arm 58, and one or more lips 64 may be provided on the mounting channel 60 to assist with positively retaining the mounting element 14 in position.

The mounting connector 54 may preferably further comprise at least one spacing ridge 66 for in use spacing the thermoelectric motor 16 from the pipe-mountable body 12. The or each spacing ridge 66 may be formed from a thermal insulator to improve this effect. Whilst a spacing ridge 66 is suggested, any spacing element which projects from the elongate arm 58 so as to act as a stop for the heat exchanger 34 may be provided.

Preferably, a height of the heat exchanger 34 is less than or equal to a height of the mounting connector 54. In use, the mounting connector 54 is able to at least in part act as a radiative baffle or break to limit radiative heating of the radiator fins 44 of the heat exchanger 34, that is, the upper parts of the heat exchanger 34, from the flue pipe.

In use, the pipe-mountable body 12 is assembled such that the magnetic elements 30 are in position in their receiving portions 26 and secured in place. The thermoelectric motor 16 can be mounted to the mounting element 14 by engaging the base portion 36 of the heat exchanger 34 on or at the mounting platform 52 of the mounting element 14. The mounting element 14 can then be attached to the pipe-mountable body 12 to fully assemble the flue-pipe fan 10.

The arcuate pipe-facing surface 18 may then be introduced to a flue pipe having a corresponding curvature. The magnetic elements 30 will clamp to the flue pipe in a strong and stable manner. A thermal conduction pathway is formed between the pipe-mountable body 12, via the mounting element 14, and into the base portion 36 of the heat exchanger 34. As such, the flue pipe is able to indirectly conductively heat the base portion 36 of the heat exchanger 34.

The radiator fins 44 of the heat exchanger 34 are only in conductive thermal contact with the flue pipe via the base portion 36. This allows them to cool much more rapidly, thereby creating a temperature differential across the vertical height of the heat exchanger 34 which can be used to power the thermoelectric motor 16, and therefore in turn, rotate the fan blade 20.

On the other hand, the positioning of the pipe-mountable body 12 and mounting element 14 occlude the radiator fins 44 from the flue pipe so as to inhibit radiative heating of the heat exchanger 34 by the flue pipe. This further improves the temperature differential of the heat exchanger 34 in use.

One risk is that the heat exchanger 34 may be knocked during operation such that the radiator fins 44 come into contact with the mounting connector 52. The provision of the or each spacing element 66 ensures that, even were the heat exchanger knocked so as to be touching the mounting connector 54, only a small area of contact is provided, due to the small surface area formed by a spacing ridge 66. This limits the potential conductive pathways between the mounting connector 54 and the heat exchanger 34, which helps to maintain the temperature gradient across the heat exchanger 34.

Figure 6 shows a second embodiment of a heat exchanger, thermoelectric motor and fan blade for a flue-pipe fan, indicated globally at 110. Identical or similar features of the second embodiment will be referred to using identical or similar reference numerals, and further detailed description will be omitted for brevity.

The second embodiment of the heat exchanger 134, thermoelectric motor 116 and fan blade 120 differs in the profile of the heat exchanger 134 and form of the fan blade 120, which is a two-bladed fan blade. Such an arrangement may have different radiative properties, and therefore may be more or less efficient that the first flue-pipe fan 10 in certain circumstances. A third embodiment of the invention is indicated in Figures 7a and 7b, showing an alternative pipe-mountable body, indicated globally at 212. Identical or similar reference numerals to those used in the first and second embodiments will be used to refer to identical or similar components, and further detailed description will be omitted for brevity.

The pipe-mountable body 212 is here provided so as to have a main body member 222 which has at least one, and preferably two, adjustable side members 268 which are movably engagable with the main body member 222. The main body member 222 and the or each side member 268 in total define the pipe-facing surface 218, which is, between the members 222, 268, at least in part curved or arcuate to complement a shape of a flue pipe.

Each adjustable side member 268 may be connected to the main body member 222 in a preferably pivotable way, for example, by the provision of hinges 270 which allow a relatively wide arc of movement such that the pipe-facing surface 218 can be adjusted for a plurality of different diameters of flue pipe. A closed condition of the pipe-mountable body 212 is shown in Figure 7a, in which the adjustable side members 268 are positioned in a forward pivoted position, which will allow the magnetic elements 230 to magnetically clamp to the flue pipe. An open condition of the pipe-mountable body 212 is shown in Figure 7b, the adjustable side members 268 having been retracted to disengage the magnetic elements 230 from the flue pipe. In this arrangement, the adjustable side members 268 effectively act as a magnetic vice or clamp around the flue pipe.

It will be appreciated that, whilst the Hue-pipe fan, also known as a stove-pipe fan device, has been described as a whole herebefore, it is possible to provide a flue-pipe fan mounting apparatus which comprises the pipe-mountable body and mounting connector, and possibly also the heat exchanger. This may allow existing stove-top fans to be retrospectively mounted to flue pipes, and may be provided as a dedicated conversion kit.

Whilst it is anticipated that the flue-pipe fan be mounted with the mounting platform at its lower end, the entire apparatus may be inverted if an appropriate temperature differential could be achieved across the heat exchanger.

It is therefore possible to provide a fan for improving circulation of air around a stove which is mountable to a flue pipe of the stove, rather than to the stove top itself. This can improve air circulation in the room, whilst limiting the risk of damage to the fan itself. This is achievable by using a magnetic clamping arrangement which allows the fan to be connected in place without compromising the required temperature gradient for its thermoelectric motor to operate.

The words ‘comprises/comprising’ and the words ‘having/including’ when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

1. A flue-pipe fan comprising a pipe-mountable body, a mounting element on the pipe-mountable body, a thermoelectric motor directly or indirectly supported by the mounting element, and a fan blade drivable by the thermoelectric motor, the pipe-mountable body having an at least in part arcuate pipe-facing surface and at least one engagement element for releasably holding the pipe-mountable body to a flue pipe.

2. A flue-pipe fan as claimed in claim 1, wherein the engagement element is a magnetic element.

3. A flue-pipe fan as claimed in claim 1 or claim 2, wherein the pipe-mountable body comprises an arcuate body member which defines the arcuate pipe-facing surface and which is at least in part receivable around an outer surface of a flue pipe.

4. A flue-pipe fan as claimed in claim 3, wherein the arcuate body member comprises at least one receiving portion within which the at least one engagement element is receivable.

5. A flue-pipe fan as claimed in claim 4, wherein the at least one receiving portion is positioned on the arcuate pipe-facing surface of the arcuate body member.

6. A flue-pipe fan as claimed in claim 4 or claim 5, wherein a plurality of said receiving portions is provided, the receiving portions being symmetrically spaced along the arcuate body member.

7. A flue-pipe fan as claimed in any one of the preceding claims, wherein the mounting element comprises a platform element and a mounting connector which is connected to the platform element, the mounting connector being connectable to the pipe-mountable body such that the platform element in use is or is substantially in a plane perpendicular to a longitudinal axis of a flue pipe.

8. A flue-pipe fan as claimed in claim 7, wherein the platform element is or is substantially perpendicular to the mounting connector.

9. A flue-pipe fan as claimed in claim 7 or claim 8, wherein the pipe-mountable body includes a mounting channel with which the mounting connector of the mounting element is engagable

10. A flue-pipe fan as claimed in any one of claims 7 to 9, wherein the mounting connector includes at least one spacing ridge for in use spacing the thermoelectric motor from the pipe-mountable body.

11. A flue-pipe fan as claimed in claim 10, wherein the at least one spacing ridge is formed from a thermal insulator.

12. A flue-pipe fan as claimed in any one of claims 7 to 11, wherein the mounting platform includes a recess with which the thermoelectric motor is positively engagable.

13. A flue-pipe fan as claimed in any one of the preceding claims, further comprising a heat exchanger to which the thermoelectric motor is mounted, the heat exchanger being mounted to the mounting element.

14. A flue-pipe fan as claimed in claim 13, wherein the pipe-mountable body and mounting element are formed from a thermally-conductive material, the pipe-mountable body and mounting element forming a thermal conduction path from the pipe-mountable body to a base of the heat exchanger.

15. A flue-pipe fan as claimed in claim 13 or claim 14, wherein a height of the heat exchanger is less than or equal to that of the mounting element, such that, in use, the mounting element acts as a radiative thermal break between a flue pipe and the heat exchanger.

16. A flue-pipe fan as claimed in any one of the preceding claims, wherein the pipe-mountable body includes a main body member and at least one adjustable side member, the or each adjustable side member being moveable relative to the main body member to alter a dimension of the arcuate pipe-facing surface.

17. A flue-pipe fan as claimed in claim 16, wherein the at least one engagement element is mounted in or on the or each adjustable side member.

18. A flue-pipe fan as claimed in claim 16 or claim 17, wherein the or each adjustable side member is hingeably engagable with the main body member.

19. A stove apparatus comprising a stove; a flue pipe connected to the stove for directing exhaust gases from the stove; and a flue-pipe fan as claimed in any one of the preceding claims, the pipe-mountable body of the flue-pipe fan being directly mounted to the flue pipe.

20. A flue-pipe fan mounting apparatus comprising a pipe-mountable body, a mounting element on the pipe-mountable body via which a thermoelectric motor may be directly or indirectly supported, the pipe-mountable body having an arcuate pipefacing surface and at least one engagement element for releasably holding the pipe-mountable body to a flue pipe.

21. A method of mounting a flue-pipe fan to a flue pipe of a stove, the method comprising the steps of: a] providing a flue-pipe fan as claimed in any one of claims 1 to 18; and b] engaging the arcuate pipe-facing surface to a flue pipe using the at least one magnetic element such that a temperature gradient can be formed at or adjacent to the mounting element to power the thermoelectric motor.