GB1591823A - Conveyor belt - Google Patents

Description

(54) CONVEYOR BELT (71) We, SOCIÉTE D'APPLI CATIONS DE PRECEDES INDUS TRIELS ET CHIMIQUES, S.A.P.I.C., a French Company of 32 rue Andrë Cayron, 92600 Asnieres, France, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The present invention relates to a transport belt for a conveyor or a bucket elevator, which is intended in particular for conveying products at a high temperature, particularly products whose temperature is higher than 2000 C.

The invention is applicable to all types of conveyor belts, particularly flexible conveyor belts, especially those of rubber, or those of silicones, plastics materials, leather, a textile material, or a metal strip.

It is quite obvious that the invention also relates to transport means, such as conveyors or bucket elevators, which are equipped with the type 6f belt whose characteristics correspond to those indicated above.

In industries such as foundry, metallurgy, steel making, the cement industry, or the glass industry, for example, the transportof products at high temperatures entails considerable problems to which no real solution has yet been found.

Two types of conveyor are used at the present time: conveyors of the flexible belt type, principally with rubber belts, and entirely metallic conveyors.

From the practical point of view conveyors of the first type offer all the advantages: their operation is regular and very flexible, and in addition they can be driven at very high speeds of the order of 4 metres per second, so that excellent productivity is achieved.

Unfortunately, conveyors of this first type have a limitation, which is obviously inherent in the materials which are used in the production of the belt. This limitation is imposed by temperature.

In this connection it will be recalled that it is well known to use for transport purposes belts made of materials having relative flexibility, among which mention may be made in particular, and without limitation, of rubbers, silicones, plastics materials, leathers, textile materials, and even belts made of metal strips, particularly belts of stainless steel.

However, on the basis of the present technology of the materials mentioned, particularly the technology of elastomers, it is considered impossible to exceed a temperature of from 200. to 2200C for the products to be transported.

In other words, it is certain that a conveyor belt produced from at least one of the materials mentioned above cannot be used for transporting products whose temperature is higher than about 200 , since the heat resistance properties of the material of which the conveyor belt is made are inadequate.

The temperature value of 200 indicated above is applicable generally, with the exception however of belts made of metal strip: in the particular case of bands of stainless steel the maximum temperature value rises to 3500C. It should nevertheless be emphasized that all the materials indicated above have the common feature that for the transport of hot products their temperature limits are in any case very low, being 200 in general and 3500 for bands of stainless steel.

As the result of all that has been stated above all-metal conveyors are therefore used in cases where the temperature of the products to be transported exceeds 200"C.

These all-metal conveyor belts can be fitted either to horizontal conveyors or to bucket elevators.

For example belts composed of overlapping metal plates and driven by chains are known. These belts have the disadvantage of leaking when carrying finegrained products or pulverulent products, as is frequently the case in the industries mentioned previously.

Conveyors are also known which are in the form of belts composed of metal mesh, which may or may not be protected by plates or containers likewise of metal.

French Patent No. 73.47129-2 212 278 and British Patent No. 1,357,276 describe more particularly a flexible belt of metal mesh protected by a series of plates which do not modify the flexibility of the belt.

Nevertheless, all these conveyors and elevators made entirely of metal which are used for transporting product at high temperature have the common feature that they operate under very poor mechanical conditions, the thermal expansions of different parts being different, and wear often being very rapid when the conveyor or elevator has to work in an atmosphere which is both radiant and dusty, for example in the presence of silica, cement, metal slag, clinker, clay, moulding sands, ingots, castings or forgings.

Furthermore, these metal conveyors, and in particularly stainless steel belts and metal mesh belts, tend to become deformed if the heat is not uniformly distributed, and their tension necessary for operating without slip is then very uncertain.

Finally, another major defect of metal conveyors is inherent to their constitution: their very conditions of operation make it necessary for them to work at low speeds, which do not exceed 1 metre per second and are generally lower than 0.5 metre per second.

It is impossible to exceed these values because any acceleration of the operation of a metal conveyor results in an increase of its defects, particularly its wear and the risk of jamming or seizing.

Thus, all-metal conveyors also have obvious limitations in their utilisation, particularly because of their unfavourable operating conditions, because of the risk of slip in the driving of the conveyors, and because of the low outputs which they yield as the result of their very slow speed of movement.

The problem of the transport of products at very high temperature may be stated thus: a) when the temperature of a product or of any part which has to be transported exceeds 200"C the conventional solution of the conveyor of the rubber belt type or of an elevator having buckets fixed on a rubber belt becomes impossible; b) at temperatures higher than 350"C even a stainless steel belt itself is no longer capable of use; c) it is then necessary to use an entirely metal conveyor or a chain elevator.

Unfortunately, this means that it is necessary to use apparatus which are often noisy, whose productivity is poor, and which are always very expensive to maintain, particularly in the case of the transporting of abrasive products such as are found in the cement, foundry, siderurgical, and glass industries.

Taking into account all that has been said above, and since the faults indicated in (c) do not occur with conveyors and elevators having a flexible belt of the rubber type, in all cases where the temperature of the products transported does not exceed the critical value of 20-220"C a conveyor having an endless belt of elastomer is used.

In cases where this critical temperature of 200220 is exceeded, it has previously been necessary to use an all-metal conveyor despite all-the disadvantages inherent in this type of conveyor, which are now well known to industrialists.

The present invention provides a conveyor or bucket elevator with a transport belt and adapted in particular for the transport of products whose temperature exceeds 200"C by the presence of metal carriers beyond a flat face of-the transport belt and defining thermally insulating air gaps between themselves and that face, the carriers being for receiving or picking up the products and being supported on the belt either directly or through support elements with only point and/or line contact between the face of the belt and the carriers or between the face of the belt and support elements and/or the support elements and the carriers, as the case may be.

A feature of this invention is therefore the use as insulating material of air whose remarkable insulating properties are well known.

This insulation by means of air should moreover be distinguished from insulations achieved by interposing a material, such as asbestos for example, between the rubber belt and the receptacle for hot products.

Because of the mechanical stresses generally imposed on conveyor belts, a cushion of asbestos bearing against a rubber belt can protect the belt from heat for only a few minutes. Its mechanical characteristics do not enable it to resist in the same way as the belt, and the cushion of asbestos will then be rapidly torn to pieces, or will disintegrate.

In a first preferred embodiment of the invention the interface between the belt and the cushion contiguous to the belt is interrupted only by point contact in another preferred embodiment the interface between the belt and the cushion contiguous to the belt is interrupted by some unidimensional parallel lines.

Various modified embodiments are also conceivable with regard to the metal means adapted to receive or pick up the hot products which are to be transported.

In a first modified embodiment these metal means rest directly on the -belt, the zones of contact between them and the belt being limited to a few points and/or to a few lines.

In a second modified embodiment these metal means are at a certain distance from the belt, and they rest on a plurality of supports inserted between them and the outer face of the belt, these inserted supports being fastened on the one hand to the belt and on the other hand to the metal means.

In the last-mentioned case the inserted supports are advantageously in the form of tubes, sections of tubes, spheres, or portions of spheres.

In a particularly interesting embodiment the metal means are made in the form of profiles forming in cross-section a succession of waves or a succession of V's.

The supports inserted between the metal means in an embodiment of this kind and the outer face of the belt are each disposed under the crest of a wave, the two flanks of the wave bearing against at least one inserted support, or at an arris formed at the intersection of two adjacent V's, each of the two V's bearing by their facing flanks against at least one inserted support.

This construction of undulating profiles or profiles formed of a succession of V's for transporting the hot products leads to zones of contact between the profiles and the rubber band, directly or through the medium of inserted supports, which are limited to simple unidimensional' lines. In other words, the heat bridges are reduced to generatrices in the case of undulating profiles, or two arrises in the case of V-shaped profiles.

Furthermore, these profiles have natural ventilation from below at the same time as the rubber conveyor belt is ventilated; moreover, the partial oyerlapping of two of ,these profiles, either on,a wave or on a V, is repeated for each profile,, makes it possible to form an endless recept.acle, of which one advantage is that it is substantially leakproof5 since grains and pulVerulent material cannot flow out between two partially overlapping profiles.

The invention also provides a belt conveyor - comprising a belt thermally insulated by means of at least one thick cushion of air from the metal means for transporting hot products. This conveyor may be a horizontal conveyor or else a bucket elevator in which each bucket is insulated from the belt by the anti-heat device mentioned above.

Because of the cushions of air judiciously placed between the metal supports, such as pallets or buckets, and the conveyor belt of rubber or stainless steel, it possible to use any belt and to keep it permanently below its limit operating temperature, and that this can be achieved without any substantial modification of the belt in question.

The invention makes it possible to attain considerably higher continuous operating temperatures, for example the transport of products whose temperature exceeds 700" is now entirely possible with a belt which previously would not have withstood a higher temperature than 200 . Similarly, the transport of products whose temperature exceeds 1000" is made possible with a belt which previously would not have withstood an operating temperature reading 3500 C.

As indicated by these figures the material of which the original belt is made very obviously has an influence on the limit operating temperature that can be tolerated after the belt made of that material has been equipped according to the invention.

Similarly, it is quite obvious that the number of insulating air cushions interposed between the conveyor belt and the metal receptacle for the hot products also has considerable influence.

Thus, for a rubber belt whose maximum continuous operating temperature is 200"C this operating temperature is brought to 500"C with a single cushion, and then to 700"C for a double cushion.

In the case of a stainless steel belt whose maximum continuous utilisation temperature is 350 , the operating temperature is brought to 6000C when the stainless steel belt is equipped with a single cushion, then to 9000C with a double cushion and to a value higher than - 1000"C for a triple cushion.

Finally the applicant company wishes to explain briefly the fundamental differences which exist between the anti-heat device of its invention and previous conveyor systems such as those described in German Patent No. 352,226, these conveyors comprising a belt on whose outer face, are fixed plates or containers whose purpose is to permit the transport of heavy products, these plates or containers being raised in relation to the belt for the sole purpose of giving them the necessary clearance to turn around the end drums driving the belt.

Conveyors of this kind are used in mines, for the extraction of blocks of products such as coal, ores, or coke, whose mass is relatively great.

In such types of conveyor the endless belt does not possess sufficient mechanical strength to support heavy masses. Thus, in order to avoid the fracture of the belt it is covered with a number of plates which are disposed one following the other and which must be placed in a raised position in relation to the belt in order to permit sufficient clearance for each change of direction of the belt.

Since the plates are raised, there is obviously an air gap between the belt and each plate.

Nevertheless this structure is quite different from that of the present invention because due to large conduction paths between the plates and the belt, which are of the essence of that proposal, substantially all heat received by the plates would be transmitted to the belt. This makes that structure unsuitable for use for carrying hot products.

The present invention proposes progressive elimination of heat from the carriers to the belt with use of one or more air cushions as an insulating medium, and also recommended are the smallest possible contacts between the supports and the belt.

Various embodiments of the invention will be described below as examples which are purely illustrative and not limitative, and with reference to the accompanying drawing, in which: Figure 1 is a view in perspective of a horizontal belt carrying profiles formed by a succession of V's resting directly on the belt; Figure 2 is a side view of a belt carrying the profiles of Figure 1 which are separated and insulated from the belt by fastening tubes; Figure 3 is a side view of a conveyor whose rubber belt carries undulating profiles fixed directly on the belt; Figure 4 is a side view of a conveyor whose rubber belt carries profiles of any kind which are separated and thermally, insulated from the belt by means of interposed supports which on the one hand are bolted to the belt and on the other hand are welded to the profiles;; Figure 5 is a side view of a rubber conveyor belt carrying V-shaped profiles providing double insulation between the hot products to be transported and the belt, the first insulation being achieved by interposed supports slipped between two adjacent V's and a second insulation by cavities provided in the bottom of the profiles; Figure 6 is a top plan view of the Vshaped profiles of Figure 5, each constituting a trough having two compartments; Figure 7 is a side view of a modification of Figures 2 and 4, in which the profiles have a flat bottom parallel to the belt and insulated from the latter by fastening tubes; Figure 8 shows three modified forms of the conveyor belt of the invention, which on its outer face carries flat metal plates adapted to receive hot products of large dimensions, these plates being thermally insulated from the belt.

a) by an undulating profile, b) by tubes or spheres, c) by a profile formed of a succession of V's; Figure 9 is a side view of an elevator whose buckets are each mounted on an insulation device having a profile composed of a succession of V's Figure 10 is a side view in which each bucket is mounted on insulating tubes; Figure 11 shows a modified version of the double insulation illustrated for the conveyor of Figure 5; Figure 12 is a top plan view of a receptacle for hot products which is composed of a planar metal sheet stamped to form frustopyramidal, frustoconical, or hemispherical cells; Figure 13 shows a method of fastening an insulating tube by bolting on the one hand to the belt and on the other hand to the receptacle for hot products.

Throughout the description given below the expression "rubber belt" will always be used both for horizontal conveyors and for bucket elevators. It is obvious that this word "rubber" is not absolutely limitative, since, as already stated, the invention is applicable to the insulation of all types of belt made of materials which do not possess a high strandard of resistance to heat. The invention is therefore not limited in its application solely to belts of rubber, but on the contrary likewise covers belts of silicones, plastics materials, leather, or textile materials, as well as belts of stainless steel whose heat resistance is likewise poor.

Referring to the drawings, it will be seen that 1 designates the rubber belt of a horizontal conveyor, and 2 the rubber belt of a bucket elevator. However, the solutions given in the description following below as anti-heat devices for a horizontal conveyor are quite obviously applicable to a vertical elevator, and vice versa, without any previous modification.

The fundamental principal of these antiheat devices, whatever the form of construction proposed, consists of the search for a minimum surface of contact between the rubber belt 1 or 2 and the metallic element which receives the products which are to be transported and which consequently is brought to a high temperature, which frequently is as high as 500 to 10000C.

This minimum contact surface has been found by utilising zones of contact with the rubber belt which are limited to points (Figures 4, 5, 7, 8b, 12), to arrises (Figures 1, 9, and 8c), or to tangent lines (Figures 2, 3, 5, 7, 8a, 8b, 10, and 11).

Point contact can for example be obtained by means of a portion of a sphere (Figure 12), or a sphere (Figures 4, 5 and 7), or by the apex of a cone or pyramid (Figure 12).

Contact by a tangent line can be obtained for example along the generatrix of a horizontal cylindrical insulating tube, along generatrices defined by the apices of undulating profiles, along arrises which define the successive dihedra of a profile formed by V's.

The invention utilises this fundamental principle in each of the embodiments which it proposes. It is then sufficient to make use of metallic means, that is to say supports receiving or picking up the hot products which are to be transported, the structure of these -means being suitable for the problems posed by the shape or dimensions of the products to be transported and by the manner in which this transport is to be effected (length of movements, slope, dimension of products, ambient atmosphere). These metal supports are therefore flat sheets, buckets, or troughs, for example, which are mounted if necessary on anti-heat devices which are also of metal and therefore resistant to higher texperatures, and which are intended to provide thermal protection for the rubber belt.

Whereas the temperature of the products transported is 500"C or even 1000 C, the temperature of the horizontal or vertical belt remains below the critical threshold of 200"C. It is clear that this protection of the rubber belt is provided by the wide air gaps, (hereinafter for simplicity referred to as a cushion) existing between the planar or profiled metal surface, which carries the hot products, and the rubber belt. This cushion of air exists over practically all the face of the belt.For example using a carrier as in Figure 12 the contact made by the system fastening the metal support on the belt is limited to a few points or with a structure such as in Figure 1, the cushion is interrupted only by a few unidimensional parallel lines represented by the apices of the profiled supports laid directly on the belt, or else by tangent lines defined along insulating tubes constituting supports interposed between the belt and the profiles in question.

When the temperature of the products to be transported does not exceed 500"C, the invention proposes to provide a number of suitable solutions offering simplified forms of construction: the use of a stamped metal sheet or of undulating or V-shaped profiles makes it possible for the anti-heat device to be used direct as member carrying the hot products. This is the case in the solutions illustrated in Figures 1, 3, and 12.

In Figure 1 a belt I is shown which carries two profiles 3 and 4 respectively, which are formed by a succession of V's. These two profiles have the same shape; they overlap partially, as indicated by the reference 5, the rear wing 6 of the profile 3 overlapping the front wing 7 of the profile 4. Lateral edges 8 and 9 on the right and left respectively delimit the profiles 3 and 4 transversely and form a bucket receptacle for the products to be transported. A number of receptacles placed on the belt 1 following one another and partially overlapping form an endless trough suitable for conveying products in the form of very fine grains, since tightness is ensured by the various overlaps.Each profile 3, 4 is fixed directly on the belt 1 by bolting, preferably utilising a bolt 10 having a wide head 11 bearing against the inside face of the belt 1, the bolt being locked on the bucket by a nut 12 screwed on behind a V-shaped wedge 13 which is placed above an upper arris 14 connecting two V-shaped dihedra. It is clear that the angle of the wedge 13 is equal to the angle of the dihedron formed along the arris 14, so that fastening can be effected without play.

The fastening device described above is particularly advantageous because the thermal connection between the buckets 3 and 4 and the belt 1 is reduced to the bottom arrises 15 and to the bolts 10; the latter transmit only a negligible amount of heat because they are fixed at the top of the upper arrises 14 and therefore are practically not in contact with the hot products carried, which mainly stagnate in the bottom portion of the buckets along the arrises 15.

It will be observed that in this embodiment the cushion of insulating air interposed between the belt 1 and the antiheat device 3, 4 fixed directly on the belt is interrupted only by some unidimensional transverse lines 15.

The antiheat device shown in Figure 3 is practically identical to the device of Figure 1, only the structure of the buckets being modified. Here each bucket has the form of an undulating profile 16 and 17 respectively, resting on the horizontal belt 1 by the generatrices 18 formed by the hollow of each wave. The buckets are fixed directly on the belt by bolts having a wide head, which are represented by their stems 10 passing through the top 19 of each wave and held by a nut 12 locked by the wedge 13.

The buckets 16 and 17 also partly overlap in the zone 5, while each of them remains insulated from the adjacent buckets. In this second example it will be observed that the insulating air cushion 20 is interrupted only by the generatrices 18.

In the example shown in Figure 12 the metal means intended to receive the hot products to be transported are made in the form of a plate 21 provided from place to place with stamped pockets having the shape of a truncated pyramid 22, a portion of a sphere 23, or a truncated cone 24. In the three types of pocket referred to the surface of contact between the belt I and the antiheat device 21 is limited to points 92 defined by the apex of the pyramid or cone or by the bottom of the portion of the sphere. The interface between the belt 1 and the insulating air cushion 20 contiguous to the belt is this time interrupted only by point contacts.

As modified embodiment the stamped pockets may be in honeycomb form.

In the most stringent cases where the temperature of the products to be transported is higher than 500"C and may be as high as 1000 C, the same basic principle of a cushion of air 20 interposed between the belt and the receptacle for the hot products is adopted, double insulation being provided in this case.

A first insulation is obtained at each metallic member carrying products and in this connection the metal member is, as in the previous case, made in the form of a profile having in cross-section a succession of V's, such as 3 and 4, or a succession of waves such as 16 and 17, or in the form of a plate such as 21 bearing by means of a series of points.

However, instead of having these metallic means (V-shaped, undulating, or in the form of stamped pockets bearing by means of points) supported directly on the rubber belt, as indicated in the three preceding examples, the metal means 3--44-116--17- 21 are on this occasion held at a certain distance from the belt, resting on a number of supports interposed between the outer place of the belt 1 and the metal profiles.

In order that the desired insulation may be obtained under the best possible conditions, it is obvious that these interposed supports themselves utilise the basic principle of the invention, that is to say their contact with the belt I on the one hand and with the metal profiles on the other hand is limited to simple points or tangent lines. The interposed supports utilised for this purpose will be tubes, sections of tubes, spheres, or portions of spheres for example. These supports will moreover be used to fasten the metal profiles on the belt, in such a manner as to reduce still further the thermal connections between the metal profiles, which are brought to a high temperature by the products transported, and the rubber belt which is to be protected.Each interposed support will therefore be fastened not only to the belt but also to the metal profile placed above and at a distance from the belt.

In the example of Figure 2 the metal profiles used are the profiles 3 and 4 of Figure 1, once again placed so as to be partially overlapping. Each profile rests on two parallel fastening tubes 25, each of these tubes being situated at the upper arris 14 defined at the intersection of two adjacent V's. It is seen that in each case the two adjacent V's bear by their facing flanks 26 and 27 against the interposed tube 25.

The transmission of the heat of the products transported to the belt is therefore still further considerably reduced. Firstly, the heat is conducted to the tubes only by the two tangent lines 28, and then it is conducted from the tubes to the belt only by the bottom generatrices 29 with intermediate dispersal due to the presence of the cushion of air 20 providing ventilation under the profiles.

The central passage 30 inside each tube 25 also assists the dissipation of heat between the tangent lines 28 and the bottom generatrix 29. This dissipation is such that in all cases the temperature of the rubber belt remains below 200"C.

Each tube 25 is fixed at its bottom to the belt 1 and by its top to a metal profile. In Figure 13 is shown a method of fixing which is particularly advantageous because it corresponds to the least possible transmission of heat from the profile to the belt.

In this respect, instead of proposing a fixing device which passes entirely through each tube 25 so as to connect a metal profile to the belt directly by means of bolts and nuts, as proposed for example in Figure 1-a device which would have the disadvantage of constituting a direct thermal connection between the hot products and the belt, the invention proposed firstly to connect each tube to a profile and then, by separate means, to connect the resulting assembly to the rubber belt. Each tube 25 accordingly has two apertures 31 (Figure 13) provided in its top portion, each in a marginal zone, and two apertures 32 provided in its bottom portion in the central zone. Opposite each aperture 31 the tube has a cutout 33 leading into the passage 30. Similarly, opposite each aperture 32 the tube has a cutout 34 which likewise leads into the central passage 30.

The two cutouts 33 are therefore disposed in the bottom portion of the tube, each in a marginal zone, while the cutouts 34 are each provided in the upper portion of the tube and in the central zone.

Finally, each profile 3 and 4 is provided along its upper arrises 14 with two apertures 35, disposed in such a manner as to be in alignment with the apertures 31 in the tube 25, and also two apertures 36 which arse disposed in the central zone and are in alignment with the cutouts 34. Similarly, each bucket 71 (Figure 7) is provided with apertures in its bottom surface, for passage of bolts 37.

The profiles 3 and 4 are then fastened to the belt I in the following manner.

A bolt 37 is introduced into each cutout 33 in such a manner that the stem of the bolt passes through the aperture 31. Each bolt head is then welded to the inside wall of each tube 25 by weld spots 93. Apertures 39 are moreover provided throughout the thickness of the belt 1 in positions corresponding to the bottom apertures 32 of the tubes 25 in each zone of the belt which is intended to receive one of these tubes.

Through the lower side of the belt a bolt 40 having a wide head 41 is then introduced into each aperture 39 and then into each aperture 32, and each of these bolts 40 is secured with the aid of a nut 42 which is introduced into the interior of the tube 25, in a position facing the stem of the bolt, by passing it into the aperture 36 and then into the cutout 34. Perfect tightening of the nut 42 against the inside wall of the tube, around the stem of the bolt 40, is achieved with the aid of a tool passing through the said aperture and the said cutout.

The tubes 25 resting on the belt 1, and then being fastened to the said belt, the metal profiles 3 and 4 are placed on the tubes 25 by bringing the apertures 35 opposite the stems of the bolts 37 and then passing each stem into the interior of the corresponding aperture until the metal profiles rest by their flanks 26 and 27 on the tubes. To complete the connection all that then remains to be done is to tighten a nut 38 on each stem of a bolt 37, which is welded by its head to an insulation tube.

The fastening system thus proposed provides two advantages: firstly no previous modification of the rubber belt is required, except of course the provision of some apertures 39 for the passage of the fastening bolts; secondly, it contributes towards the desired dissipation of heat between the metal profile and the belt since there is no direct thermal connection between a bolt 37 and a bolt 40, the connection being made indirectly through the side wall of the tube 25, thus ensuring much greater dissipation because the surface along which heat is exchanged is larger.

In the example shown in Figure 4 the metal profiles used have a shape roughly similar to an omega. Viewed in longitudinal section in this Figure, each profile 43--44 therefore has a front gutter 45 and a rear gutter 46 under which are interposed preferably hollow spheres 47 whose diameter is greater than the height of the gutter. The profiles 43 and 44 are thus placed above the belt 1 and there is now no direct thermal connection between the profiles and the belt. A first insulation is provided by the cushion of air 20 interposed between the upper face of the rubber belt and the lower face of the metal profiles. A second insulation is provided by the hollow spheres 47, which have only two point contacts 48 and 49 with each profile and one point contact with the rubber belt.

Each sphere 47 is fastened both to a metal profile and to the belt. In order to avoid direct transmission of heat from a profile to the belt through a single fastening device, use is here made, as in the preceding example, of separate connections for each sphere to the profile on the one hand and to the belt on the other hand. Since the spheres 47 are of metal, they are welded to the flanks of the gutters 45 or 46 by spot welds 48 and 49. Each sphere is then fixed to the rubber belt by means of a bolt represented in the drawing by its axis 51 passing through the bottom tangential point 50 of the belt 1 on the sphere.

In this example the zones of contact between the metal parts and the belt are limited to a few points 50.

In still more stringent cases where greater thermal protection is required, for example in cases where the resistance to heat of the rubber belt is poor, the invention permits the presence of a plurality of air cushions 20 interposed between the belt and the receptacle for the hot products.

This solution provides another advantage: for the same rubber belt whose limit of resistance to heat is conventionally from 200 to 220or, the transmission of heat is limited on each occasion by multiplying the insulation stages, and consequently it becomes possible to transport products whose temperature is still higher by using more than two insulating cushions.

In Figures 5, 6 and 11 twd embodiments are shown which have an additional stage of thermal insulation in the bottom of the metal profiles. It is however clear that without departing from the scope of the present invention it is possible to conceive similarly the utilisation of metal profiles having two, three, or even more insulation stages interposed in the bottom of the metal means, which remains insulated from the belt through the first cushion of air 20.

In the first embodiment, which is shown in Figures 5 and 6, each metal profile 52, 53 has a general shape identical to the profiles 3 and 4 described previously, but this time is supplemented by an internal transverse partition 54 and by a rear partition 55 parallel thereto. The purpose of the partitions 54 and 55 is to retain the products in cases where the belt conveyor 1 raises the products in the direction 56 inclined at a great angle to the horizontal, represented in the drawing by the dot-dash line 57.

Above the flanks 26 and 27 of the V's each profile has a horizontal floor 58 extending from the upper front arris 59 to the upper rear arris 60. Each profile 52, 53 thus contains in itself, because of the cavities 61 left between the floor 58 and the flanks 26, 27, a cushion of air which, in conjunction with the first cushion of air 20 insulating the profiles from the belt, will further assist the dissipation of heat.

In order to increase this dissipation still further, the profiles 52 and 53 are obviously insulated from the belt by interposed supports, either in the form of tubes 25 fixed to the profiles by first bolts 37 and to the belt by second bolts 40 (as shown in Figure 13), or by hollow spheres 47 fastened to the profiles and to the belt as already indicated in Figure 4 that is to say by spot welds 48 and 49 and by bolts 51 respectively.

Viewed from above in Figure 6, the profiles 52 and 53 can be seen moreover to have along their front arris 59 the two apertures 36 provided in their central portion for the passage and handling of the fastening nuts 42, and also the two apertures 35 which are each provided in a marginal zone and which permit the passage of the stem of the bolt 37 and enable the tubes 25 to be fastened to the metal profiles by means of the nut 38.

In the second embodiment, illustrated in Figure 11, the bottom of the metal profile 62 is provided with a horizontal floor 63 connected to the succession of V's by a front wall 64 and a rear wall 65. The cavity 66 bounded between these parts constitutes the first insulation against the hot products placed on the floor 63. The profile 62 is insulated from the belt by means of tubes 25 resting against the flanks 26 and 27 of the V's. The tubes are fastened in the manner illustrated in Figure 13. Between the lower arrises 15 of the V's and the belt 1 there thus exists a thick cushion of air which contributes towards protecting the belt.

For the profiles 62 provision has also been made for a partly overlapping arrangement between them, in such a manner that a transport device having no discontinuities is obtained. A U-section 67 is used for example, and is welded by one flange to the wall 65 so as to form a gutter 68 which in its interior receives a lug 69 provided on the front portion of the following profile, below a partition 70 whose purpose is to permit the transport of the hot products along a steeply sloping conveyor.

In cases where the hot products to be transported require carrier profiles having a flat bottom, the simplest insulation will be provided by the carrier elements supported by interposed supports according to the invention, as already described in connection with Figures 2, 4, 5, 11, and 13.

Referring to Figure 7, a number of identical buckets 71 are provided, whose flat bottom 72 rests on insulating tubes 25 or insulating spheres 47 as described previously. The tubes 25 used with the rear bucket are fixed to the bucket and to the belt I by the bolts 37 and 40 respectively.

The speres 47 used with the front bucket are for example welded by a spot weld 73 under the flat bottom of the bucket in question, and each of them is fixed by a bolt 51 through cooperation with apertures provided for the purpose in the belt 1.

The buckets are thermally insulated from one another, but they partly overlap through the action of their front portions 74, which are in the shape of an inverted U and between the flanges of which the raised rear edge 75 of the preceding bucket is interposed. A vertical wall 76 permits the utilisation of such buckets for the transport of products on an inclined conveyor.

In the case of Figure 7, the insulation of the belt is effected by a single cushion of air 20, the thickness of which is equal to the diameter of the insulating tubes or spheres.

Figure 8 shows three arrangements having a flat surface for the transport of long loads. Referring to Figure 8a, the arrangement shown comprises a flat plate 77 whose bottom face is spot welded along the upper generatrices 78 of an undulating profile 79 fixed to the horizontal belt 1 by bolts 40 having a wide head 41 and secured by nuts 42 after passing through holes 39 provided for the purpose in the belt 1. This system of fastening is identical to that proposed for the bottom part of the tubes 25 and illustrated in Figure 13. Holes 80 formed in the plate 77 permit the introduction and tightening of the nuts 42.

In Figure 8b is shown a flat plate 81 whose bottom face is welded to the top of hollow spheres 47 secured to the belt 1 by bolts 51 passing through the holes 39.

In Figure 8c is shown a flat plate 82 whose bottom face is spot welded to the upper arrises 83 of a metal profile 84 formed by a succession of V's. The profile 84 is fixed to the belt by bolts of the type 4041 referred to previously, whose stems pass through the holes 39 formed in the belt, so as to be secured in nuts 42 introduced and manipulated with the aid of apertures 85 provided facing the holes 39 and extending through the entire thickness of the plate 82.

The arrangement shown in Figure 8b, which uses hollow spheres 47 for insulation purposes, can obviously be applied without further modification to insulating tubes 25 of the type described previously, particularly in connection with Figures 2 and 13.

It has already been indicated that the invention is also applicable to vertical bucket elevators.

In this connection, it will be seen on reference to Figure 9 that a vertical belt 2 is shown on which V-shaped profiles 86 are bolted. The bolting is of the type proposed in Figure 8c. However, in the case of an elevator a single bolting along the upper arris 87 of each profile 86 is sufficient, since the whole of the bottom portion of the profile in question is applied against the rubber belt by simple gravity. Each of the buckets 88, which are separated from one another, is welded by its rear face 89 parallel to the belt 2 on at least two arrises 90 of the profiles on the opposite side to the arrises 87 bearing against the belt.

It is clear that in this embodiment the insulation arrangement proposed in the form of V-shaped profiles may be replaced by undulating profiles of the type shown in Figure 8a.

Figure 10 shows an anti-heat device fairly similar to that of Figure 9, for a bucket elevator. The cushion of air 20 thermally insulating the rubber belt 2 from the buckets 88 is obtained by interposing tubes 25 bolted on the belt through holes 39 and bolted on the buckets, or else spot welded, along their upper generatrices 91, as shown in the drawing.

It should be noted that in all the embodiments described above which utilise the basic principle of endeavouring to obtain minimum contact between the carrier profile (or its support) and the belt which is to be protected, it is permissible to retain the entire original transport means (conveyor or elevator) having a rubber belt.

In its practical application this results in very flexible operation of the rubber belt provided with its anti-heat device or devices, because in fact the flexibility of the new transport system is the same as that of the rubber belt. The operation of all transport means equipped in the manner proposed by the invention is moreover noiseless, gives rise to no heterogeneous expansion because each insulated metal carrier profile has complete autonomy in respect of expansion, while there is no risk of slipping because the rubber belt works under normal conditions of temperature and tension, so that perfect driving is ensured, and at very high speeds which may be as high as 4 metres per second, since the drive of the belt is not in itself modified by the addition of the anti-heat devices.

The invention is naturally not limited to the modes of application or-to the forms of construction which have been mentioned, and various modifications could be conceived without thereby departing from the scope of the present invention. This applies particularly to the shape of the metal profiles supporting the products, which shape may vary widely; the profiles may be of any type, having a flat or profiled bottom, with or without edge pieces, with or without partitions depending on the inclination of the conveyor, and with or without overlapping between two elements, depending on the nature of the products to be transported.Any of these metal profiles can be thermally insulated from the rubber belt which is to be protected, by means of at least one cushion of air 20 of the type shown in Figures 1 to 5 and 7 to 11, the thickness of this cushion of air being between 10 and 150 mm, preferably between 25 and 60 mm. It is clear that the thickness of the cushion of air is moreover technically suitable for parameters such as: temperature of the hot products to be transported, resistance to heat of the elastomer of which the belt 1 or 2 is made, the proportion of impurities contained in the air because of the environment, and the loads transported.

This thickness is obviously the greater, the greater the risk of transmission of heat from the products to the belt, whether this risk is due to transmission by conduction, by convection, or by radiation.

In a construction of this kind the belt can easily be insulated thermally from the hot products, because in effect a cushion of air is formed between the bottom face of the said receptacle and the outer face of the belt, the reliefs provided on the said outer face limiting to a few points, and/or to a few parallel or intersecting lines, the zones of contact between the hot receptacle and the belt which is to be protected. It is clear that the height of the points and/or of the ribs, since this height is equivalent to the thickness of the cushion of air, must be calculated with the greatest precision because it will determine the quality of the insulation.

The metal means may rest directly on the said points or the said lines but, as an abvious modification, the interposed supports provided in Figures 2, 4, 5, 7, 8, 9, 10, Il, and 13 may be interposed between the belt which is to be protected and the hot receptacle.

It should be observed that the device proposed by the invention permits all combinations of conveying and elevation through the multiple shapes of receptacles available: flat pallets for bulky hot loads (Figure 8), partioned pallets for steep slopes (Figures 5, 7, and 11), buckets for elevators (Figures 9 and 10).

Better still, the device of the invention makes it possible for conveying and elevating to be combined in a single apparatus, with all the desired inflexions of slope (concave or convex).

Whatever their design, all the illustrated apparatuses designed according to the present invention are extremely reliable and can ensure excellent resistance: to heat (higher than 1000 C), to wear (minimum maintenance costs), to the most severe conditions of use (abrasive powders, violent shocks, for example).

WHAT WE CLAIM IS: 1. A conveyor or bucket elevator with a transport belt and adapted in particular for the transport of products whose temperature exceeds 200"C by the presence of metal carriers beyond a flat face of the transport belt and defining thermally insulating air gaps between themselves and that face, the carriers being for receiving or picking up the products and being supported on the belt either directly or through support elements with only point and/or line contact between the face of the belt and the carriers or between the face of the belt and support elements and/or the support elements and the carriers, as the case may be.

2. A belt according to claim 1 wherein the metal carriers are spaced from the belt and rest on a plurality of support elements interposed between them and the face of the belt, these interposed supports being fastened on the one hand to the belt and on the other hand to the metal carriers and being in the form of tubes, sections of tubes, spheres, or portions of spheres.

3. A belt according to claim I or claim 2 wherein the metal carriers have facing the belt profiles forming (in longitudinal crosssection along the belt) a succession of waves or a succession of V's.

4. A belt according to claim 3 wherein said support elements are interposed between the metal carriers and the face of the belt and are disposed under the apex of a wave with the two flanks of the wave in question bearing against at least one interposed support element or at an arris defined at the intersection of two adjacent V's, a leg of each of the two V's abutting on at least one interposed support element.

5. A belt according to claim 1 or claim 2 wherein the bases of the metal carriers facing the conveyor belt are plates having honeycomb, hemispherical, frustopyramidal, or frustoconical sockets.

6. A belt according to any one of the preceding claims wherein the carriers include within themselves a thermally insulating air gap.

7. A belt according to any one of the preceding claims wherein the metal carriers are disposed one following the other with over-lapping in order to constitute an endless array.

8. A belt according to any one of the preceding claims wherein the belt is a solid belt made of rubber or rubber-like material or metal strip.

9. A conveyor belt substantially as herein described with reference to and as shown in the accompanying drawings.

10. A belt type transport means, such as a conveyor or bucket elevator apparatus, intended in particularly for transporting products whose temperature exceeds 200"C which is provided with a belt according to any of claims 1--9.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. apparatuses designed according to the present invention are extremely reliable and can ensure excellent resistance: to heat (higher than 1000 C), to wear (minimum maintenance costs), to the most severe conditions of use (abrasive powders, violent shocks, for example). WHAT WE CLAIM IS:

1. A conveyor or bucket elevator with a transport belt and adapted in particular for the transport of products whose temperature exceeds 200"C by the presence of metal carriers beyond a flat face of the transport belt and defining thermally insulating air gaps between themselves and that face, the carriers being for receiving or picking up the products and being supported on the belt either directly or through support elements with only point and/or line contact between the face of the belt and the carriers or between the face of the belt and support elements and/or the support elements and the carriers, as the case may be.

2. A belt according to claim 1 wherein the metal carriers are spaced from the belt and rest on a plurality of support elements interposed between them and the face of the belt, these interposed supports being fastened on the one hand to the belt and on the other hand to the metal carriers and being in the form of tubes, sections of tubes, spheres, or portions of spheres.

3. A belt according to claim I or claim 2 wherein the metal carriers have facing the belt profiles forming (in longitudinal crosssection along the belt) a succession of waves or a succession of V's.

4. A belt according to claim 3 wherein said support elements are interposed between the metal carriers and the face of the belt and are disposed under the apex of a wave with the two flanks of the wave in question bearing against at least one interposed support element or at an arris defined at the intersection of two adjacent V's, a leg of each of the two V's abutting on at least one interposed support element.

5. A belt according to claim 1 or claim 2 wherein the bases of the metal carriers facing the conveyor belt are plates having honeycomb, hemispherical, frustopyramidal, or frustoconical sockets.

6. A belt according to any one of the preceding claims wherein the carriers include within themselves a thermally insulating air gap.

7. A belt according to any one of the preceding claims wherein the metal carriers are disposed one following the other with over-lapping in order to constitute an endless array.

8. A belt according to any one of the preceding claims wherein the belt is a solid belt made of rubber or rubber-like material or metal strip.

9. A conveyor belt substantially as herein described with reference to and as shown in the accompanying drawings.

10. A belt type transport means, such as a conveyor or bucket elevator apparatus, intended in particularly for transporting products whose temperature exceeds 200"C which is provided with a belt according to any of claims 1--9.