SE1050327A1

SE1050327A1 - Hub

Info

Publication number: SE1050327A1
Application number: SE1050327A
Authority: SE
Inventors: Mikael Swanteson; Stina Delin
Priority date: 2010-04-06
Filing date: 2010-04-06
Publication date: 2011-08-23
Also published as: SE534435C2; EP2375211A2

Abstract

100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm ll ABSTRACT A hub (100) for a therrnal Wheel of a rotary heat exchanger is provided. Thehub (100) has a cylindrical and longitudinal body (110, 120), having a centrally alignedand longitudinally extending lun1en or through hole (116) for receiving a support axis,said support axis suspending the therrnal Wheel of the rotary heat exchanger, Wherein atleast the surface of the cylindrical and longitudinal body (110, 120) facing the support axis is of a polynieric material. Elected for publication: Fig. 1

Description

100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm l ASSIGNEE: JIJ-PLAST AB AND HEATEX AB TITLE: A HUB FIELD OF THE INVENTIONThe present invention relates to a hub. More particularly, the present inventionrelates to a hub arranged to transmit rotational movement to a therrnal wheel of a rotary heat exchanger.

PRIOR ART Hubs are commonly used for allowing a wheel to rotate relative a fixedsupport. In many applications, bearings may be assembled to form a hub for allowingthe wheel to rotate at low friction relative the stationary support.

In the field of rotary heat exchangers, i.e. heat exchangers having a therrnalwheel, hubs are inserted at the rotational axis of the rotating therrnal wheel to allowthem to rotate during use. As of today, such hubs may have metal ball bearings or slidebearings for enabling such rotation. Rotary heat exchangers of this type are readilyavailable from a number of manufacturers.

The diameters of commercially available rotary heat exchangers are typicallybetween 500 and 2500 mm. As the size of the therrnal wheel increases the demands onthe hub does too..

However, using bearings of known types for forrning hubs of a rotary heatexchanger has a number of disadvantages. Hubs having metal ball bearings and/or slidebearings are often very complex constructions, having small tolerances and being madeto a particular size of the therrnal wheel to fit properly. Moreover such hubs are heavy,leading to increased energy consumption during operation. Also, ball bearings of smalldiameters are more prone to decreased bearing capacity during prolonged use, due to theproportional negative effect of adhering dust, dirt etc.

As therrnal wheels may vary between different standard thicknesses, adistributor or manufacturer of hubs must hold hubs of all sizes in stock for fast delivery.

This elevates storage charges, thus leading to more expensive hubs.

SUMMARY OF THE INVENTIONIt is an object of the invention to provide a hub that fully or partially overcomes the above-mentioned drawbacks of prior art hubs. Moreover, a further object 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm 2 is to provide a hub that is versatile and may easily be adjusted to fit different sizes oftherrnal wheels. A yet further object of the present invention is to provide a hub that isless expensive to manufacture, still providing suff1cient properties for the particularapplication. A still further object of the present invention is to provide a hub that allowsfor reduced energy consumption during operation of the rotary heat exchanger.

According to a first aspect of the invention, a hub for a therrnal wheel of arotary heat exchanger is provided, having a cylindrical and longitudinal body, having acentrally aligned and longitudinally extending lumen or through hole for receiving asupport axis, said support axis suspending the therrnal wheel of the rotary heatexchanger, wherein at least the surface of the cylindrical and longitudinal body facingthe support axis is of a polymeric material.

The hub may be entirely made of a polymeric material, which is advantageousin that the hub may be manufactured using simple processes, and in that the materialcosts are reduced.

The polymeric material may be a therrnoplastic material, and the therrnoplasticmaterial may be POM. Hence, the hub may be manufactured by means of injectionmolding which is a well known and cost effective process.

The cylindrical and longitudinal body may comprise a cylindrical memberextending along a rotational axis of said therrnal wheel, said cylindrical member havinga first end comprising said lumen or through hole and means for connecting saidcylindrical member to a driving system, and an end portion comprising a lumen orthrough hole for receiving said support axis, said end portion being insertable into saidcylindrical member at a second end being opposite the first end. This is advantageous inthat manufacturing is facilitated.

The cylindrical member may comprise a topographical pattem at its interiorsurface, such that the end portion is prevented from being inserted beyond said pattem.This ensures that mounting may be performed by the end user, since unintendedmounting is prevented by the pattem.

The thickness of the end portion may be either equal or twice the distancebetween the pattem and the second end. Hence, the end portion may be used to close theopen end or to form an interrnediate member for connecting two cylindrical bodies.

The first end of the cylindrical member may comprise a centrally alignedlumen or through hole, and at least one recess arranged off-center. This facilitates mounting of the therrnal wheel onto the hub. 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm 3 The end portion may comprise a central portion extending from a first side to asecond side, at least one sector extending radially from said first side of said centralportion, and at least one sector extending radially from said second side of said centralportion, wherein the central portion and the sectors are forrning a circular end piece. Theend portion may further comprise three sectors extending radially from said first side ofsaid central portion and three sectors extending radially from said second side of saidcentral portion, wherein each sector extending radially from said first side is arrangedangularly adj acent to two sectors extending radially from said second side. Moreover,each sector extending radially from said first side may be connected to a sectorextending radially from said second side by means of a member extending from the firstside to the second side. This is advantageous in that the end portion may carry twolongitudinal bodies such that the force on the end portion is distributed uniforrnly on thefirst and second sides, leading to a rigid and resistant construction.

The hub may further comprise a second cylindrical member extending along arotational axis of said therrnal wheel, said cylindrical member having a first endcomprising said lumen or through hole, wherein said end portion is simultaneouslyinsertable into the cylindrical member and the second cylindrical member thus forrninga connection between the cylindrical members. Hence, hubs of different dimensions may be provided in a simple and flexible way.

BRIEF DESCRIPTION OF THE DRAWINGS Hereinafter, the invention will be described with reference to the appendeddrawings, wherein: Fig. 1 is a perspective view of a therrnal wheel of a rotary heat exchanger.

Fig. 2 is a perspective view of a hub according to an embodiment of the presentinvention; Fig. 3 is an exploded view of a hub according to an embodiment of the presentinvention; and Fig. 4 is an exploded view of a hub according to a further embodiment of thepresent invention; and Fig. 5 is a semi-exploded view of a hub according to a yet further embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm 4 With reference to Fig. 1, a therrnal wheel 10 of a rotary heat exchanger isshown. The therrnal wheel 10 is formed by a central hub 100 and a matrix 200 that isconnected to the hub 100. The hub 100 is a longitudinal and tubular body, having acentral lumen for receiving a support axis (not shown). The support axis suspends thetherrnal Wheel 10 in an operating position wherein the therrnal wheel 10 is allowed torotate relative the support axis. The hub 100 has an outer surface facing the matrix 200,and the therrnal wheel 10 is preferably mounted in a casing (not shown) to form a rotaryheat exchanger. Additional components are thus required, including a drive system,sealings, and the provision of a ﬂuid ﬂow. As rotary heat exchangers are well known,the physical principles of operation will not be described in detail.

The drive system (not shown) typically comprises an electrical motor designedto rotate at 0,5 to 20 rounds per minute. The rotational shaft of the electrical motor isconnected to a pulley that drives an endless belt. The endless belt is further connected tothe therrnal wheel 10, either at its periphery or by means of a bearing connected to thehub 100. Hence, when the electrical motor is running the therrnal wheel 10 willconsequently also rotate. A control system may also be provided for regulating therotational speed of the therrnal wheel 10. This is advantageous in applications where therotational speed needs monitoring for optimizing the efficiency of the heat exchanger.

Now referring to Fig. 2, a hub 100 according to an embodiment is shown. Thehub 100 has an inner surface, i.e. the surface that during operation is facing the supportaxis, of a polymeric material. The present inventors have surprisingly found that a hubof a polymeric material still satisf1es the bearing demands for small rotational heatexchangers. Thus, ball bearings may be omitted in such small rotational heatexchangers. Conveniently, to avoid complicated laminating steps, the hub 100 isentirely made of a polymeric material. In this way the hub 100 in its entirety or hubparts assembled into the hub 100 may be molded, such as injection molded, resulting inan easy and cost-effective manufacturing process. It is however within the inventiveconcept to manufacture the hub 100 from a core in another material than polymericmaterial, whereafter the core is coated with a polymeric material. The polymericmaterial may suitably be a plastic material. Preferably, the plastic material is atherrnoplastic material. When the polymeric material is a therrnoplastic material, thematerial may be reused, once the hub 100 has been wom sufficiently long. Also,therrnoplastic materials facilitate the manufacturing process and the quality of the hub,because of the shapability making injection mo lding possible, which in tum allows for improved surface control and thus decreased risk of uneven running. When the 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm 5 therrnoplastic material is an acetal based plastic, such as POM (polyoxymethylene),further benef1cial effects are obtained because of (i) the high chemical resistance andresistance to base hydrolysis, leading to reluctant reaction with environmentalsubstances, making the heat exchanger suitable for an improved number of settings; and(ii) the low water absorption, leading to decreased risk of metal oxidation in theinterface between the therrnal wheel and the hub.

The hub 100 comprises a longitudinal and cylindrical member 110 having anouter diameter corresponding to the inner diameter of the therrnal wheel 10. Hence, thecylindrical member 110 may be inserted and fitted into the therrnal wheel 10. Thecylindrical member 110 has a first end 112, and an open second end 114. The first end112 has a centrally aligned and longitudinal extending lumen or through hole 116 and atleast one recess 118 being aligned off center. The cylindrical member 110 furthercomprises a longitudinal slit 119 extending longitudinally from one end to the other onthe outside of the cylindrical member 110. The recess 118 and the slit 119 are providedto facilitate mounting and monitoring of the rotational matrix, as will be furtherdescribed later on.

With reference to Fig. 3, the hub 100 further comprises a circular end portion120a being insertable into the open end 114 of the cylindrical member 110. The endportion 120a has a centrally aligned lumen or through hole 122 that is aligned with thethrough hole of the first end when the end portion 120a is inserted in the cylindricalmember 1 10.

When the assembled hub is positioned inside the therrnal wheel, the hub willallow a rotational movement to be transmitted from the hub to the therrnal wheel, orvice versa. The hub is thus connected to a central axis, extending through the hub viathe centrally aligned through holes 116, 122. The therrnal wheel is thus allowed torotate relative the support axis by means of the drive system. The drive system mayeither be connected to the outer periphery of the therrnal wheel or to the hub by meansof the belt..

The end portion 120a has a central portion 124 that encloses the through hole122, which central portion 124 extends from a first side 126 to a second side 128.Sectors 130, 132 are arranged between the central portion 124 and the periphery of theend portion 120. Three sectors 130a, b, and c are arranged at the first side 126 of the endportion 120, extending radially perpendicular to the axis of the through hole 122.Further, three sectors 132a, b, and c are arranged at the second side 128 of the end 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm 6 portion 120, extending radially perpendicular to the axis of the through hole 122. Eachsector 130a-c, 132a-c is 60° wide.

Each sector 130a-c being arranged at the first side 126 is arranged adjacent totwo sectors 132a-c being arranged at the second side 128, and being connected to thesesectors by means of a connecting member 134 extending perpendicular to the axis of thethrough hole 122 and perpendicular to the sectors 130, 132.

The relative dimensions of the end portion 120a may be Varied. For example,the radius of the central portion 124 may be made larger and the radius of each sector130, 132 may be made smaller, correspondingly. This may be advantageous in that thebody mass of the end portion 120a is made larger, thus increasing the capability ofcarrying load. In an altemative embodiment, the central portion 124 may be madesmaller such that it merely enclo ses the through hole 122. This may be advantageous incases where the load to carry is small, in which case the weight and material costs maybe reduced.

In altemative embodiments, the number of sectors 130, 132 is varied from twoand upwards. For such embodiments, the number of sectors 130 extending from the firstside 126 equals the number of sectors extending from the second side 128. Further, theangular width of the sectors is substantially the same.

The periphery of the end portion 120a is adapted to fit the interior surface ofthe open end 114 of the cylindrical member 110. For this purpose, the inner diameter ofthe cylindrical member 110 is slightly enlarged at the open end 114 by means of acircumferential edge 115. The interior surface of the open end 114 further comprises atopographical pattem 140 being arranged at the enlarged inner diameter. The pattem140 has a number of circumferential protrusions 142 being equal to the total number ofsectors 130, 132, each protrusion having the same angular width as the sectors 130, 132.The protrusions 142 are spaced apart by a distance being equal to the thickness of theconnecting member 134. The width of each protrusion is further designed to be equal,or slightly less, than the axial distance between the interior surfaces of two oppositesectors 130, 132.

The end portion 120a is designed to fit with the interior surface of thecylindrical member 110 such that the end portion 120a is prevented from moving bothaxially and radially.

In a second embodiment, as is shown in Fig. 4, the thickness of the end portion120b is twice as large as the end portion 120a shown in Fig. 3, i.e. twice as large as the distance between the open end 114 of the cylindrical member 110 and the edge where 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm 7 the inner diameter of the cylindrical member 110 is changed. Hence, when the endportion 120b is inserted into a cylindrical member 110, half of the end portion 120b willextend outside the cylindrical member 110 and this part may thus be inserted into asecond cylindrical member 110. This is shown in Fig. 5.

When two cylindrical members 110 are connected, the interrnediate portion120b is designed to fit with the interior surface of the cylindrical members 110 such thatthe interrnediate portion 120b is prevented from moving both axially and radially.Consequently, the cylindrical members 110 are secured and are not allowed to moverelative each other.

Having access to end portions 120a, b having different thicknesses, hubs ofdifferent length may be easily assembled. Consequently, a number of different therrnalwheel thicknesses may be fitted easily be combining standard hub parts.

In the following, a scenario will be described wherein a hub producer ismanufacturing cylindrical members 110 having a length of 100 and 150 mm,respectively. End portions 120a, b having a thickness of 10 and 20 mm, respectively arealso manufactured. By assembling a cylindrical member and a 10 mm end portion, or byassembling two cylindrical members via a 20 mm end portion hubs of 100, 150, 200,250 or 300 mm length may be assembled.

In the following, a method for providing a therrnal wheel of a rotary heatexchanger will be described. In a first step, sheets of foil material are provided. Suchmaterial may for example be a first planar sheet and a second corrugated sheet, arrangedon top of the planar sheet. The material of the sheets may be any material being suitablefor therrnal wheels, such as pure aluminum, aluminum coated with epoxy for use incorrosive environments, or aluminum being treated chemically for providing ahygroscopic or an adsorptive material. The sheets of material are cut to have a widthcorresponding to the final thickness of the therrnal wheel. In other embodiments, thematerial of the sheets may be paper or carton, fabric, or polymeric material.

In a following step, a hub according to what has been described above isprovided. The hub is assembled either by a solitary cylindrical member and acorresponding end piece, or by connecting two cylindrical members by means of aninterrnediate end piece acting as a connecting member.

The hub is then mounted on a driving device that is connected to the off-centerrecesses of the closed end of the hub. Further, one free end of the sheets of material is fastened in the longitudinal slit of the cylindrical member. 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm 8 When the driving device is activated, the hub Will rotate and the sheets ofmaterial Will be rolled onto the hub. The hub is rotated until the radius of the therrnalWheel equals a predeterrnined value, or When the sheets of material are completelyrolled onto the hub. After this, a casing may be provided for preventing the free end ofthe sheets of material to move away from the therrnal Wheel. The casing may forexample be provided as the outerrnost revolutions of sheet material being gluedtogether, or as a tape or other polymeric material.

The present invention has been described above With reference to speciﬁcembodiments. HoWever, other embodiments than the above described are equallypossible Within the scope of the invention. The invention is only limited by theappended claims.

Claims

1. A hub (100) for a therrnal Wheel of a rotary heat exchanger, said hub (100)having a cylindrical and longitudinal body (110, 120), having a centrally aligned andlongitudinally extending lumen or through hole (116) for receiving a support axis, saidsupport axis suspending the therrnal Wheel of the rotary heat exchanger, Wherein at leastthe surface of the cylindrical and longitudinal body (110, 120) facing the support axis is of a polymeric material.

2. The hub according to claim 1, Wherein the hub (100) is entirely made of a polymeric material.

3. The hub according to claim 2, Wherein the polymeric material is a therrnoplastic material.

4. The hub according to claim 3, Wherein the therrnoplastic material is POM.

5. The hub according to any one of claims 1 to 4, Wherein the cylindrical andlongitudinal body comprises a cylindrical member (110) extending along a rotational axis of said therrnalWheel, said cylindrical member (110) having a first end (112) comprising said lumen orthrough hole (116) and means (118) for connecting said cylindrical member to adriving system, and an end portion (120) comprising a lumen or through hole (122) for receivingsaid support axis, said end portion (120) being insertable into said cylindrical member(110) at a second end (114) being opposite the first end (112).

6. The hub according to claim 5, Wherein the cylindrical member (110)comprises a topographical pattem (115, 140) at its interior surface, such that the end portion (120) is prevented from being inserted beyond said pattem (115, 140).

7. The hub according to claim 6, Wherein the thickness of the end portion (120)is either equal or twice the distance between the pattem (115, 140) and the second end(1 14). 100406 P:\7368_JiJfPlast\P\002\to be filed\P73680002fl00309fapplicationtext.docm

8. The hub according to any one of claims 5 to 7, Wherein the first end (112) ofthe cylindrical member (110) comprises a centrally aligned lumen or through hole (116), and at least one recess (118) arranged off-center.

9. The hub according to any one of claims 5 to 8, Wherein the end portion (120)comprises a central portion (124) extending from a first side (126) to a second side(128), at least one sector (130) extending radially from said first side (126) of saidcentral portion (124), and at least one sector (132) extending radially from said secondside (128) of said central portion (124), Wherein the central portion (124) and the sectors(130, 132) are forrning a circular end piece (120).

10. The hub according to claim 9, Wherein the end portion (120) comprisesthree sectors (130a-c) extending radially from said first side (126) of said central portion(124) and three sectors (132a-c) extending radially from said second side (128) of saidcentral portion (124), Wherein each sector (130a-c) extending radially from said firstside (126) is arranged angularly adjacent to two sectors (132a-c) extending radially fromsaid second side (128).

11. The hub according to claims 9 or 10, Wherein each sector (130) extendingradially from said first side (126) is connected to a sector (132) extending radially fromsaid second side (128) by means of a member (134) extending from the first side (126)to the second side (128).

12. The hub according to any one of claims 5 to 11, ﬁarther comprising asecond cylindrical member (110) extending along a rotational axis of said therrnalWheel, said cylindrical member (110) having a first end (112) comprising said lumen orthrough hole (116), Wherein said end portion (120b) is simultaneously insertable intothe cylindrical member (110) and the second cylindrical member (110) thus forrning a connection between the cylindrical members (110).