GB2423038A

GB2423038A - Assembly apparatus

Info

Publication number: GB2423038A
Application number: GB0501246A
Authority: GB
Inventors: Colin Hargreaves
Original assignee: Emerson and Renwick Ltd
Current assignee: Emerson and Renwick Ltd
Priority date: 2005-01-21
Filing date: 2005-01-21
Publication date: 2006-08-16
Also published as: GB0501246D0

Abstract

The invention provides an apparatus 2 for assembling a heat exchanger core matrix, and comprises tube feed means 14 for feeding heat exchanger tubes 10 to a support surface 8, and fin feed means 6 for feeding exchanger fins 22 to the support surface 8. In use, the apparatus 2 is operable to feed tubes 10 to the support surface 8, and also simultaneously insert fins 22 between tubes 10 on the support surface 8 to thereby assemble the core matrix. The invention further provides a method for assembling a heat exchanger core matrix, and a heat exchanger core matrix assembled using either the apparatus or the method.

Description

ASSEMBLY APPARATUS

The present invention relates to apparatus and methods for assembling a core of a heat exchanger, which may be used in automobiles. The invention extends to heat exchangers manufactured using the apparatus and/or method.

Heat exchanger cores of the kind with which the present invention are concerned, consist of a plurality of flattened tubes that are positioned parallel with, and coplanar to, one another, with the tubes being spaced apart by respective corrugated sheet metal elements, which are referred to as fin assemblies or fins.

Hence, the heat exchanger core consists of a matrix of alternatively spaced tubes and fins. A pre-determined number of tubes and fins in a matrix are then secured together by means of first and second header plates each having apertures therein for receiving opposite ends of the tubes to form a heat exchanger. C.. *

Machines are known for assembling heat exchanger cores, for example, the: ..

apparatus disclosed in EP 0,342,975 B 1. The known apparatus includes a tube. S storage/supply area where the heat exchanger tubes are produced and stored, a fin storage/supply area where the fins are produced and stored, and a matrix assembly:...:.

area where the fins are integrated in between the tubes to produce the final core *...

matrix. The apparatus includes two paddlewheels, which rotate and thereby move * .*.

tubes one by one from the tube storage area, and place them on to a support surface. .. : The tubes are then advanced (or indexed) along the support surface by means of rotating scroll drums to the matrix assembly area, at which point the scroll drums stop rotating. A single fin is then inserted in between the space between the pair of stationary tubes to form a tube-fin-tube assembly.

Once the fin has been dropped in position between the pair of tubes, the scroll drums are then rotated again to thereby move the tube-fin-tube assembly further along the support surface. The paddlewheels are rotated to thereby take a new tube from the tube storage area and place it on the support surface. The next fin is then inserted between the next pair of parallel tubes. The process of positioning the tubes and moving them along the support surface, and inserting fins in between the stationary tubes is repeated until a final core matrix has been assembled.

Problems associated with the known apparatus are that the speed of producing heat exchanger cores is dictated by the synchronous assembly of the heat exchanger tubes with the fins. Hence, the insertion of fins has to be fully synchronised with the presentation of tubes on the support surface. This poses problems as each system has to synchronise with the other precisely, with the speed of insertion of fins severely restricting the speed of assembly of the final core.

Further problems include the fact that each fin has to be settled in position on the support surface and come fully to rest before the tubefin-tube assembly can be indexed out of the way by the scroll drums, in order to allow the next fin to be inserted between the next set of parallel tubes. As each fin is moved from the fin supply area to in between the tubes, it will have an inertia or momentum, and this momentum determines the time required to allow it to come fully to rest in between the tubes before it can be moved along. Furthermore, it is important that each fin is:. . accurately inserted between each pair of tubes to avoid damage to either the fin or either of the pair of tubes. As a result, there is a limitation on how fast the fins can be * inserted in between the tubes. On average, the time required for each fin to be inserted and indexed along is about 0.9s. S...

Accordingly, the insertion of the fins in between the tubes severely restricts 5....

the speed of assembly of the core matrix, and therefore considerably decreases the: production rate that can be achieved by the apparatus.

It is therefore an aim of embodiments of the present invention to address the problems with the prior art, and to provide an improved apparatus and a quicker method for assembling a heat exchanger core matrix.

According to a first aspect of the present invention, there is provided apparatus for assembling a heat exchanger core matrix, the apparatus comprising:- (i) tube feed means for feeding heat exchanger tubes to a support surface; and (ii) fin feed means for feeding heat exchanger fins to the support surface; wherein, in use, the apparatus is operable to feed tubes to the support surface, and simultaneously insert fins between tubes on the support surface to thereby assemble a core matrix.

Known machines are unable to simultaneously feed tubes on to the support surface as well as insert a fin in between a pair of tubes. Accordingly, they are subject to considerable speed limitations during the process of assembling a heat exchanger core matrix. Hence, advantageously, because the apparatus according to the invention is able to simultaneously feed fins in between the tubes on the support surface to form the heat exchanger core matrix at the same time as feeding tubes on to the support surface, it is much more efficient, and exhibits an increased turnover rate of assembly of core matrices. : .

S S

S S S.

Preferably, the apparatus comprises tube storage means in which heat exchanger tubes may be stored. Preferably, the tube feed means is operable to feed a *..:.

tube from said tube storage means to the support surface. Preferably, the feed means *US S is operable to feed a plurality of tubes on the support surface, thereby forming a tube * array thereon. By the term "tube array", we mean a plurality of tubes that are positioned substantially parallel with, and substantially coplanar to, one another.

Preferably, the apparatus comprises a tube array assembly area in which the array of tubes is assembled on the support surface. Preferably, the tube array assembly area is the part of the support surface that is substantially proximal (or adjacent) to the tube storage means. Preferably, the apparatus comprises a core matrix assembly area in which the core matrix is assembled. Preferably, the core matrix assembly area is the part of the support surface that is substantially distal to (or away from) the tube storage means.

By the term "heat exchanger core matrix", we mean a plurality of tubes that are positioned substantially parallel with, and substantially coplanar to, one another, with the tubes being spaced apart by fins.

By the term "fin" or "fin element", we mean a substantially corrugated sheet metal element, which is inserted between the tubes to form the core matrix.

Preferably, the tube storage means comprises two spaced apart, mutually opposing side walls, which may be held in position by at least one cross bar extending therebetween. Preferably, the tube storage means is adapted to store a plurality of tubes therein, preferably in a substantially vertical stack. Each side wall may comprise guide means, which guide means is adapted to help keep the tube stack correctly aligned in the tube storage means, and assist feeding the tubes to the tube array assembly area. Preferably, the guide means comprises a slot extending vertically downwardly along the centre of an inner side of at least one side wall. Hence, the tubes may be stored in a vertical stack, with each end of each tube being located in the slot of each side wall. * S

*S**..

The cross-section of the tubes may be substantially flattened, i.e. a generally **** elongate elliptical shape as opposed to the usual circular or plain elliptical shape. S...

Hence, preferably, the tube storage means is adapted to store a plurality of tubes in a.. : substantially vertical stack, wherein the stack is arranged in use to retain relatively flattened tubes in a substantially horizontal orientation.

Preferably, the tube feed means comprises at least one rotatably mounted wheel or drum, which wheel in use is adapted as it rotates to move a tube from the tube storage means to the support surface, and preferably the tube array assembly area thereof. Preferably, the at least one wheel is rotatably mounted on an axle, which may extend between the two side walls of the tube storage means. Preferably, the wheel comprises a slot in the circumference thereof, which slot is operable to receive at least a portion of the tube in the tube storage means. Hence, preferably, in use, the tube in the tube storage means rests upon an upper edge of the wheel so that, as the wheel rotates, the slot moves passed tubes in the tube storage means, and thereby receives a tube. Preferably, the wheel is adapted to rotate so that the tube received in the circumferential slot is moved from the tube storage means to the support surface, and preferably, the tube array assembly area. It is especially preferred that the tube supply means comprises two spaced apart wheels, which are preferably rotatably supported between the lowermost part of the two side walls of the tube storage means.

Preferably, the apparatus comprises indexing means operable to move at least one tube along the support surface, and preferably a tube array along the support surface. It is especially preferred that the indexing means is adapted to move at least one tube from the tube array assembly area to the core matrix assembly area. The indexing means may be supported in position above the support surface by fixing means. Preferably, the fixing means are positioned at either end of the indexing means, and about midway therealong.

Preferably, the indexing means comprises first and second portions, which: ..

may interface with each other at an interface position. Preferably, the first portion of * the indexing means extends along (and corresponds to) the tube array assembly area, and preferably, the second portion of the indexing means extends along (and * corresponds to) the core matrix assembly area. Preferably, the first and second portions of the indexing means are adapted to rotate either dependently or * . S*u independently of one another. Hence, the two portions may be operable to rotate at the.. : same time, speed, and/or direction as each other. Alternatively, the two portions may be adapted to rotate at different times, speeds and/or directions as each other. Hence, the first and second portions of the indexing means may be coupled, or de-coupled, from each other, wherein rotation thereof is independently controllable.

Preferably, the first and second portions of the indexing means are operable to be independently rotated with respect to each other. For example, the first portion may be operable to rotate in either direction, preferably, at any speed, while the second portion is operable to remain substantially stationary. Similarly, the second portion may be operable to rotate in either direction while the first portion may be operable to remain substantially stationary.

Preferably, the indexing means comprises friction reducing means at or adjacent the interface position between the first and second portions thereof, which friction reducing means may be operable to allow the first and second portions to rotate dependently or independently of each other. The skilled technician will appreciate the different types of friction reducing means, which could be used between the first and second portions of the indexing means. For example, the friction reducing means may comprise a bearing. The bearing may be a joumalled bearing, or a rolling elements bearing. Examples of a suitable bearing that could be between the first and second portions comprise a ball bearing type, or a needle bearing type, or an oil bearing type.

Hence, for a ball bearing type, the bearing may comprise a radially positioned inner bearing seat, and preferably a radially positioned outer bearing seat. Preferably, at least one ball bearing may be housed between the inner and outer bearing seats. :. .

S

Preferably, the apparatus comprises drive means operable to rotate the first * s and second portions of the indexing means. The drive means may comprise separate motor drive units for rotating the first and second portions of the indexing means. * * **5**S Hence, the apparatus may comprise first drive means operable to drive the first S...

portion of the indexing means, and second drive means operable to drive the second S...

portion of the indexing means. The second portion of the indexing means may.. : comprise an axle or spindle, which axle extends along the inside of the first portion, to allow independent rotation of the second portion. Preferably, the second drive means is operatively linked to the axle.

Preferably, the indexing means comprises a helical groove or thread that extends along the longitudinal axis thereof, which thread is suitably sized to receive (and accommodate) a tube. It will be appreciated that the heat exchanger core may be used in many different situations, for example, as a heat exchanger in an automobile.

It will also be appreciated that because the sizes of automobiles vary, so will the shape and dimensions of the heat exchanger, and hence, heat exchanger core. Accordingly, the number and sizes of heat exchanger tubes and fins will also vary between different types of automobiles. Preferably, the thread in the first and second portions of the indexing means is aligned at the interface section, to thereby form a continuous thread along the total length of the indexing means.

In one embodiment, the first portion of the indexing means may comprise a groove in which the pitch or width thereof is substantially the same as the groove in the second portion of the indexing means. In an alternative embodiment, the first portion of the indexing means may comprise a groove in which the pitch or width thereof is different to the groove in the second portion of the indexing means. Hence, the first portion of the indexing means may comprise a groove in which the pitch is more or less than the pitch of the groove in the second portion of the indexing means.

For example, the pitch of the thread in the first portion may be approximately half the width of the pitch of the thread in the second section of the indexing means.

Advantageously, having a smaller pitch in the first portion of the indexing means reduces the required length of the first portion for the indexing means for a given number of tubes required for a tube array. This means the total length of the indexing: . . means may be reduced.

Advantages of having a longer pitch of thread in the second portion of the indexing means are that the tubes are further apart as they are advanced from the tube array assembly area to the core matrix assembly area, and this allows a higher speed of fin insertion to be used. This results in a much more reliable process.

Preferably, in use, the first portion of the indexing means is operable to move tubes forming a tube array away from the tube storage means towards the interface position of the indexing means. Preferably, in use, the indexing means is operable to rotate about its longitudinal axis, to thereby move the tube array along the support surface away from the tube storage means to the core matrix assembly area.

Preferably, once the desired number of tubes are present in the array, the first portion of the indexing means is operable to move the tube array from the tube array assembly area to the core matrix assembly area. Preferably, with the tube array in the core matrix assembly area, the second portion of the indexing means is then operable to keep the array in a stationary position, such that fins may be inserted by the fin feed means in between the tubes to thereby form a core matrix. Preferably, the first portion of the indexing means is operable to continue to form a tube array in the tube array assembly area while the fins are being inserted. Hence, the apparatus is operable to insert at least one fin in to a first tube array in the core matrix assembly area, while at the same time forming a second array in the tube array assembly area.

The indexing means may comprise at least one scroll drum or scroll screw, which preferably, extends away from the tube array assembly area to the core matrix assembly area. Preferably, the first and second portions of the indexing means correspond to first and second portions of the screw. Preferably, the indexing means comprises two parallel, spaced apart scroll screws. Preferably, the distance between the two scroll screws is approximately the same as the length of each tube, such that a tube may be received between the two screws, preferably within the helical grooves thereof. Preferably, the scroll screws are rotatable about their longitudinal axis, and in use, are operable to move a tube along the support surface away from the tube storage means to the core matrix assembly area. Preferably, in use, simultaneous rotation of: ..

the two screws in the same direction causes the helical groove or thread to effectively move along the longitudinal axes thereof. Hence, in use, as a tube is slotted in to the groove of the thread, the two screws are adapted to rotate to thereby urge the tube by the thread in between the two screws along the support table.

Preferably, in use, the apparatus is operable to simultaneously insert a plurality,0 of fins between the tubes of at least one tube array to thereby assemble a core matrix at the same time as feeding tubes to the support surface. By "plurality of fins", we mean that a series of fins are inserted between corresponding series of tubes in the tube array, to thereby produce the core matrix. Advantageously, inserting a plurality of fins between the tubes in the tube array at the same time greatly increases the capacity and turnover rate of the apparatus.

It is preferred that the fin feed means is operable to simultaneously feed a complete compliment of fins in any core between corresponding tubes in the tube array. For example, the heat exchanger may consist of 40 tubes and 41 fins. Hence, the full compliment of fins will be 41. Alternatively, the heat exchanger may consist of 50 tubes and 51 fins. Hence, the full compliment of fins will be 51. However, it is preferred that the fin feed means is operable to simultaneously feed at least two fins between corresponding tubes in the tube array (i.e. two fins between a total of four tubes), and more preferably, at least 5 fins (i.e. five fins between a total of ten tubes), fins, 15 fins, 20 fins, 25 fins, 30 fins, 35 fins, 40 fins, 45 fins, and most preferably at least 50 fins at the same time. It will be appreciated that an average automobile heat exchanger consists of about 40-50 tubes (or more) separated by 41-5 1 fins (or more).

Hence, it would be most desirable and advantageous for the apparatus to insert all 41 or 51 fins in to the tube array simultaneously.

The apparatus may be operable to simultaneously insert a plurality of fins between a plurality of tube arrays to thereby assemble a core matrix. For example, multiple rows of tube arrays may be used, e.g. a two or even three row heat exchanger is envisaged. In a two row radiator, there is provided a first lower tube array and a second upper tube array, and the fin feed means is preferably operable to insert the fins in to both arrays simultaneously. For example, the lower and upper tube arrays may consist of 50 tubes each (i.e. 100 tubes in total), and 51 fins are then inserted, and of sufficient width to extend across both tube arrays to form a two row radiator. S Where multiple row heat exchanger are assembled, the indexing means preferably comprises a plurality of scroll drums or screws positioned at appropriate S...

positions, and adapted in use to each move tube arrays to the fin insertion position of.1 I. the apparatus.

Preferably, the fin feed means comprises a fin mill, in which fins may be prepared. The fin feed means may comprise fin storage means in which or on which fins may be stored prior to supplying fins to the core matrix assembly area. The fin storage means may comprise a substantially planar surface on which the fins are stored. The fin storage means may comprise fin separation means adapted to keep the fins separate prior to their insertion between the tubes. The fin separation means may comprise a plurality of spaced apart flanges extending transversely away from the surface. Preferably, the flanges are substantially parallel with each other.

The fin separation means is preferably adapted to align the fins with the tubes in the array prior to insertion therebetween to form the matrix. The fin feed means may comprise fin delivery means extending between the fin mill and the fin storage means. The fin delivery means may comprise a chute, which may be at an angle with respect to the support surface.

According to a second aspect of the present invention, there is provided a method of assembling a heat exchanger core matrix, the method comprising the steps of:- (i) feeding heat exchanger tubes to a support surface to form a tube array; and (ii) simultaneously feeding heat exchanger fins to the support surface, and inserting fins between tubes on the support surface, to thereby assemble a core matrix. S. * * S * * *5

Preferably, the method is carried out using apparatus in accordance with the. . first aspect. Advantageously, and preferably, the method according to the second aspect allows an increased turnover of core matrices due to the fact that multiple fins are inserted in between the tubes of a first tube array at the same time as further tubes are fed on to the support surface to form a second tube array. *::: :* S.. * S *

S

Preferably, the tubes are moved to the support surface from tube storage means, preferably, by tube feed means. Preferably, the first array of tubes is formed in a tube array assembly area, which array is moved or indexed by the indexing means towards a core matrix assembly area.

Preferably, the indexing means comprises first and second portions, which may be independently rotatable with respect to each other. When the first array of tubes is located in the core matrix assembly area, the first and second portions of the indexing means may be de-coupled, such that the second portion maintains the first tube array in position. Preferably, a plurality of fins may then be inserted by fin feed means in between the tubes of the array, while simultaneously the tube feed means continues to move tubes on to the surface, and the first portion of the indexing means continues to move the tubes along the surface to thereby form the second tube array.

The first and second portions of the indexing means are then re-coupled such that the completed core matrix comprising the first tube array can then be moved away by the second portion of the indexing means, and the second tube array can be moved in to the core matrix assembly area by the first portion of the indexing means.

The process may then be repeated wherein tube arrays are produced in the tube array assembly area and then moved to the core matrix assembly area for fin insertion, and so on. It is preferred that a plurality of fins are fed in to the tubes array at the same time. This increases the tumovcr rate of producing core matrices compared to when inserting only a single fin.

The indexing means may comprise a scroll drum or screw, and preferably two scroll drums or screws. Hence, it will be appreciated that sequential coupling and * :* decoupling of the first and second portions of the indexing means makes it possible to keep the first tube array in position while fins are being inserted, while at the same time a second tube array can be moved from the array assembly area towards the core matrix assembly area.

According to a third aspect of the invention, there is provided a heat exchanger: core matrix assembled using the apparatus according to the first aspect, or the method.

according to the second aspect.

The heat exchanger core matrix may be used to prepare a heat exchanger for use in an automobile. The heat exchanger may be used as a radiator, a heater, a condenser, and evaporator, or an oil cooler.

All of the features described herein (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined with any of the above aspects in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:- Figure 1 illustrates a perspective view of an apparatus according to the invention used for the manufacture of a core of tubes and fins, for example, for use as a heat exchanger; Figure 2 illustrates a plan view of the apparatus in a first configuration; Figure 3 illustrates a plan view of the apparatus in a second configuration; Figure 4 illustrates a plan view of the apparatus in a third configuration; Figure 5 illustrates a plan view of the apparatus in a fourth configuration; Figure 6 illustrates a side view of a scroll screw as used in the apparatus shown in Figure 1; and Figure 7 illustrates an enlarged cross-sectional view along line A-A of the scroll screw shown in Figure 6. * *

SI....

Referring to Figure 1, there is shown an apparatus 2 used for the manufacture of a heat exchanger 3, for example, for use as an automobile radiator. The radiator 3 * S...

consists of a core of parallel, spaced apart flattened cooler tubes 10, which are separated by a series of corrugated fins 22. Figure 1 shows the layout of the apparatus 2, Figures 2 to 5 illustrate the apparatus 2 in use during manufacture of a radiator 3, and Figures 6 and 7 show enlarged, detailed views of the apparatus 2.

Referring to Figure 1, the apparatus 2 consists of a horizontal support table 8 on to which the flattened tubes 10 are placed and supported. During manufacture of a heat exchanger 3, the tubes 10 are moved by means of two parallel scroll drums or scroll screws 16 from a tube storage/delivery section 5 located at one end of the table 8 to the opposite end of the table 8, where the fins 22 are slotted in to position between the array of tubes 10, thereby forming a core. The apparatus 2 will now be described in more detail.

At one end of the table 8 (the left hand side of Figure 1), there is provided a tube storage/delivery section 5 in which an array of flattened tubes 10 are stored. The tube storage/delivery section 5 consists of two spaced apart, mutually opposing side walls 4, which are held in position by a cross bars (not shown) extending therebetween. Each side wall 4 has a slot 24 extending vertically downwardly along the centre of an inner side thereof. The array of tubes 10 is stored in a vertical stack 12, with each cnd of each tube 10 being located in the slot 24 of each side wall 4 of the storage/delivery section 5. Hence, the slots 24 help to keep the tube stack 12 correctly aligned in the storage/delivery section 5, and assist feeding the tubes 10 on to the support table 8.

The tube storage/delivery section 5 further includes two paddlewheels 14 that are rotatably supported between the lowermost part of the two side walls 4 below the tube stack 12. The two paddlewheels 14 are rotatably mounted on an axle 28, which extends between the two side walls 5. In use, the tube 10 that is located at the bottom * . : of the vertical tube stack 12 rests upon an upper edge or face of each paddlewh eel 14 * so that, as the paddlewheels 14 rotate in a direction indicated by arrow A in Figure 1, a slot (not shown) present in the circumference of each paddlewheel 14, moves passed the base of the tube stack 12, and thereby receives an end of the lowermost tube 10.

The paddlewheels 14 continue to rotate in the direction of arrow A so that the tube 10 now carried in the circumferential slot is carried away from the tube stack 12, and is eventually lowered down on to the support table8. Figure 1 illustrates two tubes 10 positioned in the slots in the paddlewheels 14 being moved around in to the table 8.

As shown in Figure 1, extending away from the tube storage/delivery section 5 along the length of the support table 8 there are provided two parallel, spaced apart scroll drums or screws 16. The distance between the two screws 16 is approximately the same as the width of each tube 10. The screws 16 are supported in position above the support table 8 by means of fixing brackets 26 positioned at both ends thereof, and about midway along the screws 16. The screws 16 are rotatable about their longitudinal axis and are arranged to move the tubes 10 along the support table 8 away from the tube 10 storage/delivery section 5 to the position on the table 8 where the fins 22 are inserted therebetween to form the final core. Figures 6 and 7 illustrate the scroll screws 16 in more detail.

Referring to Figures 1, 6 and 7, each screw 16 is shown being divided into two, independently rotatable, screw sections: (i) section A; and (ii) section B, each of which extend along the same longitudinal axis, thereby defining the screw 16. As shown in Figure 1, section A is located substantially adjacent the tube storage/delivery section 5, and section B is located at the opposite end of the support table 8 away from the tube storage/delivery section 5. The two sections A and B of each screw 16 meet and interface with each other at position 34. Each section A, B, of each screw 16 has a helical groove or thread 36, which thread 36 is suitably sized to receive a flattened tube 10.

The thread 36 of sections A and B of the screw 16 is aligned at the interface position 34 to thereby form a continuous thread 36 along the total length of the screw 16, as shown in Figure 7. Simultaneous rotation of the two screws 16 in the same direction causes the helical groove or thread 36 to effectively move along the longitudinal axes thereof. Hence, when a tube 10 is slotted in to the groove of the thread 36, as the two screws 16 rotate, the tube 10 is urged by the thread 36 in:. .:.

between the two screws 16 along the support table 8. * ** S...

As shown in Figures 6 and 7, rotation of section A and section B of each screw *..* 16 is powered by separate drive units 38, 40. Rotation of section A of each screw 16 is powered by a drive input 38, and rotation of section B of each screw 16 is powered by a drive spindle 40. The drive spindle 40 extends through the inside of section A of the screw 16 and is surrounded by space 42 so that as the spindle 40 rotates, it does not touch or interfere with the inside of section A of the screw 16.

Each screw 16 can operate in essentially two ways:- (i) The separate motor drive units 38, 40 for sections A, B of each screw 16 can be set so that section A and section B of each screw 16 rotate simultaneously with each other in the same direction and at the same speed, so that the entire screw 16 rotates. in so doing, the helical groove of the thread 36 extends along the entire length of the screw 16, and effectively moves along the longitudinal axis thereof thereby carrying a tube 10 from one end of the support table 8 to the other. This is possible when the two motor drive units 38, 40 are set to rotate their respective section A, B at the same speed and in the same direction. In this arrangement, the sections A and B of each screw 16 are said to be coupled togcther. It will be appreciated that in order to carry a tube along the support table 8, both scroll screws 16 need to rotate at the same speed and in the same direction so that the helical grooves in each screw 16 in which the respective ends of each tube 10 are located, move along the table in the same direction and at the same rate.

(ii) The screws 16 may be arranged so that each section A, B of a screw 16 is able to rotate independently with respect to the other section A, B of the same screw 16. Hence, each screw 16 can be arranged in use so that section A of each screw 16 rotates, but so that section B of each screw 16 does not rotate, and vice versa, if * required. In this arrangement, the sections A and B are said to be de-coupled from a each other. The purpose of this will be described hereinafter.

As shown in Figure 7, the interface section 34 between section A and section: B of each screw 16 includes a location/rotary bearing, which allows the two sections A, B to rotate independently of each other. The bearing at the interface section 34:::: includes a radially positioned inner bearing seat 48, and a radially positioned outer ** bearing seat 46 between which ball bearings 44 are housed. In order to rotate both sections A and B of each screw 16 simultaneously, the motor drive units 38, 40 are set to rotate the two sections A and B at the same speed and in the same direction. The two sections A and B of the screw 16 are coupled', and there is no respective movement therebetween, and the rotary bearing does not come in to play. However, in order to stop section B from rotating, but allow section A to rotate independently of stationary section B, the motor drive 38 for section A is set to rotate, and the motor drive 40 for section B is actuated, such that section B remains stationary. Hence, the two sections A and B of the screw 16 are de-coupled' from each other, and the rotary bearing allows section A to rotate while section B does not. The use of the two scroll screws 16 to move the tubes 10 from the tube storage/delivery section 5 to fin 22 insertion position will be described in further detail hereinafter.

Referring to Figure 1, the fins 22 that are used to make the heat exchanger 3 are produced in a fin mill 6. The fin mill 6 is located adjacent the support table 8 at the end which is opposite to the position of the tube storage/delivery section 5 (the right hand side of Figure 1). Hence, the fin mill 6 is adjacent the position where the fins 22 will be inserted in between the array of tubes 10 to form the final core of the radiator 3. A fin chute 18 extends between the fin mill 6 and a fin storage tray 20 upon which the fins 22 are supported prior to insertion between the tubes 10. The fin storage tray 20 is therefore a temporary holding area for the fins 22, and includes a series of parallel, spaced apart fin separators 32, which are provided to help separate, and correctly align, the fins 22 with the tubes 10 before insertion therebetween.

The process for manufacturing a heat exchanger 3 using the apparatus 2 will now be described with reference to Figures 2 to 5, which show the two parallel scroll screws 16 by which the tubes 10 are moved from one side of the support table 8 to the other. For convenience, the tube storage/delivery section 5 has been omitted from the Figures. However, it will be appreciated that the tube storage/delivery section 5 would * be present on the left hand side of the screws 16 shown in the Figures. In addition, in Figures 2 to 5, the line indicated by X-X represents the split line 34 between sections:: ::: A and B of each screw 16.

A tube 10 is first taken from the bottom of the tube stack 12 by the rotating paddlewheels 14, and is then carried down and place on to the support table 8. The ends of the tube 10 are slotted in to the helical groove of the thread 36 in each drum screw 16, which are positioned underneath the paddlewheels 14. Hence, eventually, the tube 10 comes to rest on the support table 8, and is positioned between the two screws 16. Both screws 16 rotate in the same direction about their longitudinal axes under the power of the drives 3 8,40 and because both ends of the tube 10 are held in the helical groove of each screw 16, the tube 10 is advanced down the support table 8 in the direction indicated by arrow B shown in Figure 2.

The rotating paddlewheels 14 are coupled to the rotating screws 16 by means of a drive wheel 30 attached to the end of the axle 28, as shown in Figure 1. Hence, as the screws 16 rotate advancing the tube 10 down the table 8, a second tube 10 is automatically taken from the bottom of the tube stack 12 by the paddlewheels 14, and moved in to position in the helical grooves of the threads 34 of the two screws 16 immediately behind the first tube 10. Therefore, continuous rotation of the paddlewheels 14 is in synchrony with the two rotating screws 16 and causes an array of tubes to be produced on the support table 8 in section A of the two screws 16, as shown in Figure 2. Figure 2 also shows a series of fins 22 supported on the fin storage tray 20, waiting to be inserted between the array of tubes 10.

Once the array of tubes 10 has been completed (i.e. about 50 tubes 10 for a typical heat exchanger 3), the tubes 10 are then rapidly moved or indexed from section A to section B of the two screws 16, as shown in Figure 3. This is achieved by increasing the rotational speed of both screws 16 under the power of motor drives 38,40. When the array of tubes 10 reach their position in section B of the screws 16 as., shown in Figure 3, section A and B of the screws 16 are de-coupled' from each other.

Hence, sections A of both screws 16 continue to rotate under the power of drive input 38, such that new tubes 10 continue to be taken from the tube stack 12 and received in the helical groove of the screw thread 34. Hence, a new (second) array of tubes 10 can be continually formed on the support table 8 in section A. As shown in Figure 3, the second array of tubes 10 is continually advanced towards the split line X-X in the direction of arrow B. However, at the same time as the second array of tubes 10 is being produced, sections B of both screws 16 are prevented from rotating by stopping the drive spindle 40. Hence, the first array of tubes 10 are currently stationary in section B of the screws 16. As described herein, the rotary bearings in the screws 16 allow section A of each screws 16 to rotate while section B of the screws 16 remains stationary. At this point, the fins 22 are moved from the fin storage tray 20 down in to the array of tubes 10, as shown in Figure 3.

Referring to Figure 4, there is shown the fins 22 being further inserted in to the spaces between the tubes 10 in the first array in section B of the screws 16.

Eventually, fin 22 insertion is completed and the final core of tubes 10 and fins 22 has been produced. In addition, Figure 4 shows the second array of tubes 10 (50 in total) has now been completed in section A of the screws 16.

Referring to Figure 5, the completed core consisting of the first array of tubes 10 and inserted fins 22, is then rapidly indexed out of section B of the screws 16, and moved to the next stage of manufacture (not shown). This is achieved by simultaneously powering the drives 3 8,40 in both screws 16 at the same speed so that the core is advanced completely out of the screws 16. Hence, the second array of tubes 10 are simultaneously rapidly indexed from section A to section B, where they are stopped for receiving a set of fins 22. The process is therefore repeated as illustrated in Figure 2, and so on. I. 0 * . .

In one embodiment of the apparatus 2, the pitch of the helical groove of the thread 36 is the same width in sections A and B. However, in another embodiment, the pitch of the thread 36 is different between the two sections A and B. For example, as shown in Figure 1, the pitch of the thread 36 in section A of the screw 16 is less (for example, about half the width) than the pitch of the thread 36 in section B of the screw 16. Advantages of having a smaller pitch in section A are that it reduces the required length of section A for each screw 16 for a given number of tubes 10 required for an array. Hence, the total length of the screw 16 is reduced, thereby allowing a shorter and therefore smaller apparatus 2. Advantages of having a longer pitch of thread in section B are that the tubes 10 are then separated apart as they are advanced from section A in to section B. This allows a higher speed of fin 22 insertion may be used. It will be appreciated that if the distance between the tubes 10 in the array is increased, it is easier to improve the accuracy of fin 22 insertion, and so the fin 22 insertion step may be accelerated, thereby increasing the rate of turnover of the apparatus 2. This results in a process which is inherently more reliable than any other known for assembling heat exchanger cores.

The assembly apparatus 2 according to the present invention gives the ability to insert multiple numbers of fins 22 in to an array of tubes 10. This significantly reduces the overall cycle time of the apparatus as in known apparatuses only one fin 22 is inserted between two tubes 10 at any time. Further advantages of the apparatus 2 reside in the effective way in which the tubes 10 can be indexed by the screws 16 from a first position where they are arranged in to an array of tubes to a second position where they can receive a plurality of fins 22, while simultaneously, a second set of tubes can be arranged in to an array on the same apparatus 2. This also increases the turnover rate of the apparatus 2, and is a vast improvement over known machines.

Taking an average heat exchanger core 3 with approximately 50 fins 22 and 49 tubes 10, a production rate of 3 cores per minute could be easily attained. Of course, with fewer fins and tubes in the core, e.g. a heater core, the production rate could easily reach 4 or even 5 cores per minute. The present state of the art machinery has difficulty in producing more than two units per minute. In addition, using the apparatus 2 of the present invention, fins 22 can be positioned accurately by the insertion method without the problems associated with a hurried dynamic system suffers from. * *

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Claims

I. Apparatus for assembling a heat exchanger core matrix, the apparatus comprising:- (iii) tube feed means for feeding heat exchanger tubes to a support surface; and (iv) fin feed means for feeding heat exchanger fins to the support surface; wherein, in use, the apparatus is operable to feed tubes to the support surface, and simultaneously insert fins between tubes on the support surface to thereby assemble a core matrix.
2. Apparatus according to claim 1, wherein the apparatus comprises tube storage means in which heat exchanger tubes are stored.
3. Apparatus according to claim 2, wherein the feed means is operable to feed a plurality of tubes on the support surface, thereby forming a tube array thereon. * *

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4. Apparatus according to any preceding claim, wherein the apparatus comprises a tube array assembly area in which the array of tubes is assembled on the support surface.
5. Apparatus according to any preceding claim, wherein the apparatus comprises a core matrix assembly area in which the core matrix is assembled.
6. Apparatus according to any preceding claim, wherein the tube feed means comprises at least one rotatably mounted wheel or drum, which wheel in use is adapted as it rotates to move a tube from the tube storage means to the support surface, and the tube array assembly area thereof.
7. Apparatus according to any preceding claim, wherein the apparatus comprises indexing means operable to move at least one tube along the support surface.
8. Apparatus according to claim 7, wherein the indexing means comprises first and second portions, which interface with each other at an interface position.
9. Apparatus according to claim 8, wherein the first and second portions of the indexing means are adapted to rotate either dependently or independently of one another.
10. Apparatus according to claim 9, wherein the first portion is operable to rotate in either direction, at any speed, while the second portion is operable to remain sub stanti ally stationary.
11. Apparatus according to any one of claims 8 to 10, wherein the indexing means comprises friction reducing means at or adjacent the interface position between the first and second portions thereof.
12. Apparatus according to claim 11, wherein the friction reducing means comprises a bearing.
13. Apparatus according to any one of claims 8 to 12, wherein the apparatus comprises drive means operable to rotate the first and second portions of the indexing means. :...:.
14. Apparatus according to any one of claims 8 to 13, wherein the apparatus:: ::: comprises first drive means operable to drive the first portion of the indexing means, and second drivc means operable to drive the second portion of the indexing means.
15. Apparatus according to claim 14, wherein the second portion of the indexing means comprises an axle or spindle, which axle extends along the inside of the first portion, to allow independent rotation of the second portion.
16. Apparatus according to any one of claims 7 to 15, wherein the indexing means comprises a helical groove or thread that extends along the longitudinal axis thereof, which thread is suitably sized to receive (and accommodate) a tube.
17. Apparatus according to claim 16, wherein the first portion of the indexing means comprises a groove in which the pitch or width thereof is different to the groove in the second portion of the indexing means.
18. Apparatus according to claim 17, wherein the first portion of the indexing means comprises a groove in which the pitch is less than the pitch of the groove in the second portion of the indexing means.
19. Apparatus according to any one of claims 7 to 18, wherein the indexing means comprises at least one scroll drum or scroll screw, which extends away from the tube array assembly area to the core matrix assembly area.
20. Apparatus according to claim 19, wherein the indexing means comprises two parallel, spaced apart scroll screws. r* .:*
21. Apparatus according to any preceding claim, wherein, in use, the apparatus is operable to simultaneously insert a plurality of fins between the tubes of at least one tube array to thereby assemble a core matrix at the same time as feeding tubes to the support surface. S... S...
22. Apparatus according to any preceding claim, wherein the fin feed means is operable to simultaneously feed a complete compliment of fins in any core between corresponding tubes in the tube array.
23. Apparatus according to any preceding claim, wherein the apparatus is operable to simultaneously insert a plurality of fins between a plurality of tube arrays to thereby assemble a core matrix.
24. Apparatus according to claim 23, wherein where a multiple row heat exchanger is assembled, the indexing means comprises a plurality of scroll drums or screws positioned at appropriate positions, and adapted in use to each move tube arrays to the fin insertion position of the apparatus.
25. Apparatus according to any preceding claim, wherein the fin feed means comprises a fin mill, in which fins may be prepared.
26. Apparatus according to any preceding claim, wherein the fin feed means comprises fin storage means in which or on which fins may be stored prior to supplying fins to the core matrix assembly area.
27. A method of assembling a heat exchanger core matrix, the method comprising the steps of:- (iii) feeding heat exchanger tubes to a support surface to form a tube array; and (iv) simultaneously feeding heat exchanger fins to the support surface, and inserting fins between tubes on the support surface, to thereby assemble a core matrix. * * *
28. A method according to claim 27 carried out using apparatus according to any one * of claims 1 to 26. * *

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29. A heat exchanger core matrix assembled using the apparatus according to any one of claims 1 to 27, or the method according to either claim 26 or claim 27. S.,.. * * S S

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