DE2133699A1 - HEAT-RESISTANT CONVEYOR BELT - Google Patents

Description

Highly heat-resistant conveyor belt The invention relates to a conveyor belt, which can be exposed to high temperatures; and a method of manufacture this tape.

It is known that in the structure of a conveyor belt two essential Elements play a role, namely the skeleton or the framework of the ligament, formed made of several layers of fabrics of different types, and a mixture for that Covering the frame, consisting of elastomers or plastics, which make up the frame protect and on the upper part of the destructive influences of the conveyed Material, namely wear, high temperature, corrosion, impact, while on the lower side of the belt the mentioned mixture is driven by the Transport drum and the movement on the guide rollers of the conveyor belt causes.

It is also known that the elastomers have limited heat resistance atifweise, which is generally guaranteed under 250 a, while in the case of transport of materials at higher temperatures destroys the protective mixture of the scaffolding will.

Furthermore, it has also been synthesized from various, natural or fabric of the scaffolding consisting of synthetic fibers has a fairly limited heat resistance, which in most cases is below the temperature value at which the mixture the top layer is decomposed, namely below 180 ... 200 ° C. At temperatures of conveyed materials of more than 1800 C will in a short time both the mixture the top layer that comes into contact with the conveyed materials as well as destroys the framework, which can no longer have the tensile strength, even existed before the tape in question was completely destroyed.

In order for these disadvantages of the classic materials, which for the Cover layer and used for the framework of the conveyor belts are a solution to find were attempts made different types of fabrics to achieve, generally using mineral fibers such as asbestos, Glass and even ceramic and metallic fabrics.

Attempts were also made to articulate the surface of the conveyor belts to cover (clad) connected plates made of ceramic or metallic materials, as protection against the harmful effects of temperature. In many cases it will be instead of the inlays that are used to make the scaffolding and made up of several types of fabrics or braids, steel cables used.

For example, a conveyor belt is known which has high temperatures Can withstand up to 500, .. 600O a and which as protection of the supporting surface of the conveyor belt ceramic, articulated plates are used as the framework of this belt consists of steel cables.

The production of such a belt system, however, encounters great technical issues Trouble. Such tapes are also perfectly rigid in the transverse direction. Further the transverse curvature that is required for a good transport performance is required.

Other known conveyor belts are used to cover the belt a protective layer made of an ordinary rubber compound, in which short, thin Pieces of wire or pieces of metal are inserted.

The disadvantage of this type of tape is that the metal, which is used in the form of short fibers or grains, a very good thermal conductivity has so that the heat of the conveyed material quickly to the adhesive layer between Rubber and metal parts are transferred, with the elastomer in the affected area is destroyed and thereby the metal parts are torn from the tape0 There are also known conveyor belts that can withstand high temperatures, their Scaffolding one or more columns of fabric made of metal threads and asbestos or glass fibers included, sometimes combined with a third type of pade, consisting of Polyesters or polyamides.

The manufacture of these systems of tissues, however, runs into great proportions technical difficulties and requires special equipment. Also sticking this is the fabric on the rubber compounds that form the supporting and rolling surfaces associated with difficulties, both in the use of tapes, which through Gumming are produced, as well as those in which the deposits through Calender processing can be achieved.

Another disadvantage of these tapes is that tapes whose Width is smaller than that of the fabric, have a significantly lower quality.

The creation of ribbons of various widths is also possible with the Difficulty connected, as a fabric of the same width for every 3-width must be available.

Conveyor belts to be used at high temperatures have recently become made, the framework of which consists exclusively of metal fabrics.

This type of tape has numerous disadvantages, one of which is the most important of which is very great rigidity, which is not a good wrap around the Drive drum allows.

Since this type of metal mesh also exists in the belt, there are tensions is exposed, the corresponding fabrics must have a corresponding rigidity, to avoid stretching during operation.

The numerous bends and bends that the tape makes on the drum exposed, however, damage the metallic insert quite quickly as a result their rigidity.

The invention overcomes these disadvantages.

The invention consists in that either a protective element from one Mixture of elastomers and asbestos flakes is used, which one is intended is that exerted by the conveyed material on the pestulence framework of the belt Reduce thermal shock, or it is used as a protective element made of a metal mesh consist of the grid used, elches flexible - both in the longitudinal and in the transverse direction - Is formed, or a combination of both elements is used.

The essence of the invention is shown below with reference to in the drawing illustrated embodiments explained in more detail which cross-sections through the Represent the conveyor belt, indicating where the strength structures are arranged are.

Embodiment 1 In a conveyor belt of conventional construction (Pig. 1), consisting of a 4 mm thick base layer 1, and also of a framework 2, consisting of inlays of polyamide fabric, furthermore the tape has a 1.5 mm thick rolling surface 3, a 4 mm thick protective element is also used 4 introduced, which on the upper side with an insert of polyamide fabric which is of the same type as the frame 2.

The rubber mixture, which is used for the production of the bearing and rolling surface is used, has the following composition, the ingredients in Parts by weight are given: 90 parts of polychloroprenic Gii-qrni; 10 parts of cis-polybutadiene rubber; 10 parts zinc oxide, 4 parts magnesium oxide, 0.6 parts of stearin; 0.4 parts of sulfur; 0.8 part of diortotolil guanidine; 50 parts Carbon black (type HAF); 7 parts of chlorinated paraffin with 70 V of chlorine; 8 parts of diphenilrezil phosphate; 10 parts of stibium trioxide; 94 parts of mercaptoimidazoline; 2 parts phenil-betanaphtalinamine; 0.8 parts of tetramethyltiuram disulfide; 20 parts of asbestos flakes.

The protective element has the following composition: 90 parts polychloroprenic rubber; 10 parts of cis-polybutadiene rubber; 10 parts of zinc oxide; 0.8 parts of stearin; 1 part of di-oratotolil guaniding, 0.8 part of tetramethyltiuram bisulfide; 10 parts of carbon black (type HAF); 17 parts of chlorinated paraffin; 10 parts of diphenyl crezil phosphate; 10 parts of stibium trioxide; 2 parts of phenyl-betanaphthylamine; 0.6 parts of sulfur; 1.2 Parts of mercaptoinmidazoline; 4 parts of magnesium oxide; 120 parts Ausbestflocken.

The asbestos flakes are in the mixture for the wing for the Rolling surface and especially for the protective element introduced to there the thermal Stability by reducing the thermal conductivity and because of its fire-resistant properties Increase properties.

The fibers of the asbestos flakes should have a length of 0.1-3 mm. With fibers smaller than 0.1 mm, the effect of reducing the thermal conductivity of the gum mixture into which the flakes are introduced is essential degraded, while with dimensions of more than 3 mm the asbestos fibers will have a hard time with the rubber mix and cause agglomerations, which affect the physico-mechanical properties reduce.

For the preparation of the mixture, rollers or an encapsulated one can be used Kneading mixers are used, taking the following technological procedure too is to be observed.

The elastomers come along with the peptizers and the antioxidants brought into a plastic state; then the asbestos flakes are cut into small ones Parts introduced, with a subsequent amount of asbestos flakes only then being introduced when the previous close has been fully absorbed.

When using a kneading mixer, the temperature in the kneading chamber should be not higher than 1000 C to avoid deterioration in the properties of the polymer to avoid as well as any cyclical changes or tendencies towards pre-vulcanization of the mixture when introducing the vulcanization factors and accelerators to prevent.

The arrangement of an insert of polyamide fabric between the Wing and the protective element causes a better solidification of the upper side of the tape and reduces the possibility of the rubber layers becoming detached from the Scaffolding, what else is the case with thicker rubber layers applied to the scaffolding Pall is 0 in any cases of detachment of parts of the rubber layer from the The surface of the tape is the progressive spread of this process through the intermediate insert prevents the damage at the relevant point of the protective element prevented.

The following results from a thermal differential analysis Properties of the mixture, on the one hand for the wing and on the other hand for the Protective element.

The absolute thermal stability, up to a temperature of 2300 C, is achieved if this temperature is maintained for a maximum of 15 minutes.

At this temperature there is a weight loss for 5 minutes of about 31 ß of the initial weight instead of, with further warming of the remainder of the mixture for 20 minutes up to 4200 a, no significant occur Changes on.

At 420 ° C a slow breakdown of the loosened material begins again, being another weight loss from 15 o / a of the initial one Weight takes place.

If the rest of the material is heated further, a third stage of decomposition of this material, which continued slowly up to 600 ° C with further weight losses of 15% occurring over approximately 10 minutes.

A further increase in temperature up to 800O a does not cause any further Weight loss.

Taking into account the conversion rate that at 170 ... 1800 a the textile insert, from which the framework is made, loses up to 50% of its properties and contributes 2100 C is completely destroyed, the need arises in an obvious way the protection of this layer by using a protective element.

From a thermal, differential analysis of a mixture without Asbestos flakes results in a value of 150 ... 210 ° C as the start of the destruction temperature, which increases rapidly, so that at 3000 C the material is completely destroyed.

The tape made in this way is non-flammable and has self-extinguishing properties.

The rubber mixture from which the 'rragfläche and the protective element are manufactured, has a heat transfer factor which is significantly lower than that of the usual mixtures.

Embodiment 2 The procedure is as in Example 1, with the The difference is that for the mixture of the bearing and rolling surfaces only 10 percent by weight Asbestos flakes are introduced so as not to reduce wear resistance, while in the mixture for the protective element 250 parts by weight of asbestos and 100 parts by weight Elastomer are introduced in order to achieve maximum strength in the event of strong thermal shocks achieve. A tape of this type has a 30% longer service life and for the touch with the conveyed materials temperatures of 700 ... 800 ° C.

Embodiment 3 The procedure is as in Example 1, with the Difference, that between the wing and that consisting of a rubber compound Protective element (Fig. 2) instead of an insert made of polyamide fabric, a grid (5) made of articulated metal mesh is used.

The articulated metal mesh is also shown in FIG. 3.

The metal mesh has diamond-shaped meshes with a large angle between the pages of 1200, which allows a good snuggling to the tro £ n-el, without stressing the sides of the grille with signs of fatigue.

Wire 1.6 mm in diameter and 13 mm mesh is used for the grid (Length of the side) and a coil height of 8 mm is used0 Such a grid is Flexible in both the transverse and longitudinal directions and enables good anchoring both in the wing and in the protective element.

The width of the wire mesh is 20% less than the total width of the belt, as the thermal loads on the lateral parts of the belt can be neglected.

In this case the thickness of the wing is 6 mm, that of the protective element 4 mm, whereby the frame consists of 3 fabric inserts.

The metallic grid 5 achieves more effective protection in the event of heat shocks and allows even the partially damaged rubber compound between the meshes can be obtained that is protected against wear and tear by the material being conveyed is.

The ratio between the thickness of the wing, plus that of the protective element and the thickness of the ollfläche is approximately 1: 7 in consideration the much more important wool of the upper part of the tape for strength under stress due to heat shocks and wear. This also applies to the scaffolding under the middle line of the tape in question what the expansions taking place in the tape reduces, since in this case the framework is only stressed with pressure effects. Hence the behavior in the event of fatigue of the material from which the framework is made is made, improved. The framework is made of fabric inserts of one width made of a maximum of 94% of the bandwidth in order to avoid the fabric sticking to it the sides of the tape emerge from it.

Embodiment 4 .itedrecovery of Example 3, however the mixtures for the wing, for the protective element and for the rolling surface are different are.

This pall contains both the wing and the protective element the same content of asbestos flakes with fiber lengths of 0.2 - 0.3 mm or parts by weight, bezones on the dlastomere.

As a structure of the recipe is used: 80 parts Neoporen id; 14th Parts Europren cis; 10 parts of ZnO; 4 parts of MgO; 1.0 part stearin; 0.6 parts of sulfur; 0.8 parts Diortotolil guanidine (DOTG); 30 parts of carbon black HAF; 20 parts Cerechlor 70; 6 parts of diphenil crezil phosphate; 10 parts of stibium trioxide; 0.4 parts Accelerator NPV; 2.35 parts of antioxidant; 0.6 part of tetra-methyl-t iuram bisulfide; 20 parts of asbestos flakes.

The rubber mixture for the rolling surface is different from that for the wing through the elastomers used, in this Pall uses: 50 parts neoprene MMV; 50 parts of ßuropren cis; 45 parts of Carom 15; 4 pieces MgO; 1.55 parts of antioxidant PBN; 0.6 parts of sulfur; 0.88 parts accelerator DOTG; 20 parts of asbestos flakes; 40 parts of carbon black HAF; 4 parts of diphenyl crezil phosphate; 10 While stibium oxide; 16.80 parts of chlorinated paraffin type Cerechlor; 1.20 parts of stearin; 0.80 parts accelerator TH; 10 parts of ZnO; 0.42 parts accelerator NPV.

On the surface of the tape, strips of polyamide fabric applied, lined with a mixture on the inside, which has the same composition as that of the rolling surface to access this Way to anchor the metal grid in the tape.

Embodiment 5 The rubber mixtures for the wing, protective element and rolling surface are produced as in Example 3.

The wire mesh grid has a width that is 5% less than the total width of the tape to protect the whole area of the tape without that, however, the wires protrude from this at the ends of the tape.

For the manufacture of the grid, wire of 0.6 mm is used; the The width of the pocket is 5 mm, the height of the turn 2.5 mm. illit a thin one Wire, a better flexibility of the tape is achieved, which drums of less Can wrap around diameter. To achieve the same wear protection effect, denser meshes are produced or meshes with a smaller side length.

The 14 metal grille is made with an isocyanate solution using known methods treated to achieve better adhesion to the rubber compound.

To create a closer bond between the asbestos flakes and the elastomer To achieve this, the asbestos flakes are soaked with a solution made up in acetone dissolved phenol-formaldehyde resin, after which the solvent is removed and the impregnated asbestos flakes for the production of the corresponding mixtures be used.

The structure of the belt is similar to that of Example 3 at a thickness of the wing of 4 mm, the protective element of 1 mm and the rolling surface of 1.5 mm.

To prevent the wire turns from coming out of the wire mesh and get to the surface of the belt, the wing becomes thicker Rubber layer used, in a ratio of 4: 1, based on the Protective element. This is also necessary in this Pall because the thinner Wire more easily to the surfaces. can arrive, and taking into account the The fact that the protective element is more rigid and the embedding of the windings in the protective element is more difficult.

Another reason for choosing this relationship between the two Rubber layers (or wing and protective element in which the grille is arranged is) consists in that the upper rubber layer with the pressure plates of the press in Contact comes, warms up and therefore the wire windings through easier penetrate the rubber layer.

Under these conditions, the upper rubber layer must enable that the grid is completely embedded in it, without the wire turns coming out to effect outward to the belt surface.

Because the tape is not stressed by too great a heat shock and because of the rigidity of the protective element due to the use of soaked asbestos flakes is increased, the thickness of this protective element was reduced to 1 mm.

Embodiment 6 The wing has a thickness of 10 mm, the rolling surface a thickness of 2.5 mm, the grid made of metal mesh is made of wire of 2.5 mm, the side length of the bag is 30 mm, the turn has a height of 15 mm.

The width of the grid is 40 ß smaller than the total width of the tape (Fig. 4).

The protective element 4 has a thickness of 2 mm and in the central part in the side parts of 1 mm. The greater thickness of the protective element in the central Part is justified by the fact that in this section the tape is subject to higher stresses is exposed.

The frame 2 consists of two laterally arranged inserts, each of a width of 30% of the total width of the belt, also of an additional insert arranged across the entire range.

To anchor the wire mesh 5, the two edges of the Two strips of polyamide fabric applied to the surface of the tape, the inside with a mixture of the same type as the wing and the have the same width as the side inlays of the scaffolding, with these strips cover an area of 10 ß of the entire bandwidth and also have the purpose of the sliding of the fabric as well as the emergence of this fabric at the edges of the tape to prevent.

The tape produced in this way can be used under very severe operating conditions - what promoted the wear and tear through that Material concerned - work, for this reason the heavy operating conditions the wing does not contain asbestos flakes, which could reduce the wear resistance. For the same reason, a thicker wire with a higher one will be used for the metal mesh Wear resistance used. By using longer asbestos fibers for the protective element is strongly crosslinked and the mixture. the influence of wear and tear the tearing out of the fibers from the mixture is reduced.

The use of thicker wires for the production of the grid is conditional an enlargement of the meshes in order to achieve the same flexibility of the belt.

Since the belt is only exposed to thermal shock in the central part, the grid is only provided with a width that corresponds to 40 9o of the bandwidth.

Since the thermal stress only affects the center of the belt, the lateral arrangement of the scaffolding inserts provides protection against premature Destruction, with a single insert arranged across the entire bandwidth being a causes sufficient rigidity. When choosing the width of the side inserts the fact that the strongest thermal stresses in the Mid-band occur, on a width of 30 ffi of the band, on both Sides of the central ligament axis.

Embodiment 7 The mixtures for the Grag and Roll surfaces are produced according to the Declmologie described in Example 1, but the content is of asbestos flakes, based on the elastomer, 50%, and the asbestos fibers have one medium length, which varies between 0.5 - 3 mm.

The grid 5 is sandwiched between two calender-rolled rubber layers 6 or 4 mm thick are used. In this case the frame is made up of 3 layers polyamidic fabric, the last of which is 30% larger in width than the total width of each side of the tape.

The last textile insert is applied over the grid on both sides, to anchor this in the tape. By using asbestos flakes for the mixture A special protective element made of elastomers is unnecessary for the wing (Fig. 5), Embodiment 8 The tape is produced as in the case of Example 7, with the difference that the deposits from which the framework is formed, on both Side parts of the belt are provided, while the last insert is on the whole Bandwidth is arranged. There are two side strips on the tape surface of polysmid fabric 6 applied to the grid 5, of a width of 30 ffi of the entire range to anchor. This type of band (Fig. 6) can only be stressed with larger heat surges in the central part, which requires a lateral arrangement of the scaffolding.

Embodiment 9 The tape is made according to the information from Example 8, with the difference that the last insert has a longer strip (of 50 0 based on the tape length) is provided, which over the grid 5 is brought to anchor ~ this (Pig. 7). From an anchoring of the lattice using the last textile insert is made use of when fabric sufficient width are available or less in the case of conveyor belts Broad.

Embodiment 10 The tape is produced as in Example 6, with the difference that the metal grid 5 is dispensed with, while the three Deposits of the frame 2 are arranged laterally and a width on both sides have, equal to 30% of the total bandwidth, while the last textile insert is arranged over the entire length of the tape (Fig. 8). This type of transpoft tape is used when the thermal stresses are not also together with Significant wear occur, so that the metal grid 5 is dispensed with can be.

Embodiment 11 The tape is produced as in Example 10, with the difference that the thickness of the protective element in the central part is 15 mm, while in the side part this value is only 10 mm.

The frame is made up of three laterally arranged textile inserts, which occupy 30 / a of the entire bandwidth on both sides, while the last Insert over the whole range on both sides by 30% larger than the first Inserts is and is arranged between the wing and the protective element to this to anchor. (Fig. 9) Since the thermal stresses on the central To impact part of the tape, the scaffolding is placed sideways using the ends of the last insert in order to better secure the protective element achieve.

Embodiment 12 The procedure is as in Example 1, with the difference is that the same mixture is used for the protective element as for the wing or with an asbestos flake content of 20 parts by weight, based on the elastomers, while the rolling surface has the following composition: 50 parts of neoprene WHV; 5 parts of Europren cis; 45 parts of Carom 1500; 4 parts Mag0; 1.55 Parts of antioxidant PbN; 1.15 parts of sulfur; 0.88 parts accelerator DOTG; 20 parts of asbestos flakes; 40 parts of carbon black HAF; 4 parts of diphenyl crezil phosphate; 10 Parts of stibium trioxide; 17 parts of chlorinated paraffin; 1.2 parts of stearin; 0.8 parts accelerator TH; 10 parts of zinc oxide; 0.42 parts Besoh1euniger NPV.

The advantages of the invention are as follows: there are conveyor belts manufactured, which can work continuously at temperatures of 160 ... 180o C, with heat shocks of up to 400 ° C for 40% of the operating time can, resp.

800 ... 900 ° C during 5 - 10% of the actual transport time of the hot Materials; - The conveyor belts can be made by standard technological processes can be manufactured without the need for special protective inserts that are difficult to manufacture; - There is a correct, appropriate arrangement of the inserts of the scaffolding achieved, depending on the working conditions with an appropriate use the textile inserts; - the conveyor belts with metallic grids are flexible and can be subjected to strong mechanical impacts.

Claims (8)

Patent claims: 1. Highly heat-resistant conveyor belt, characterized in that for the purpose Achieving an increased service life at high temperatures as well as an increased Wear resistance a protective element (4) is provided, consisting of a mixture of elastomers and asbestos flakes and / or a grid (5) made of articulated Metal mesh, flexible both in the transverse and longitudinal direction. 2. A method for the production of the conveyor belt according to claim 1, characterized in that a protective element between the wing and the frame (2) (4) is arranged, consisting of a mixture of highly heat-resistant elastomers, in which asbestos flakes in a proportion of 10 - 250 parts by weight, based on the elastomer, are introduced, with asbestos of a fiber length between 0.1 - 5 mm is used, which is introduced in its natural form or which is previously treated with an adhesive, the protective element still or only consists of an articulated metal grid (5), both flexible in the transverse as well as in the longitudinal direction, made of wire with a diameter of 0.6 - 2.5 mm, whereby the angle between the Masohenseiten can have values between 30 ... 120 ° and where the side length of the mesh is between 5 - 30 mm and the height of the May have turns between 2.5 and 15 mm. 3. The method according to claim 2, characterized in that the protective element (4), consisting of a mixture of slastomeres and flakes of asbestos a thickness between 1 ... 5 mm, which over the entire width of the band or only in the central Part of the belt is retained, while the side parts have a maximum thickness 25 ffi have the corresponding thickness of the central part. 4. The method according to claim 3, characterized in that the protective element (4) consists of a mixture of elastomers and asbestos flakes and either directly is arranged under the wing or between the wing and protective element a textile insert is switched on, this insert of the same type is like the deposits from the framework of the corresponding band, or that with severe temperature conditions but the protective element with low tensile forces is arranged above and below the frame and therefore also the role of the support and the rolling surface has. 5. The method according to claim 3, characterized in that the metallic Lattice is introduced either directly into the structure of the belt or beforehand treated with an adhesive, such as. B. with Isozianaten that the metal grid for treatment is inserted between two calender-rolled rubber sheets, and that the thickness ratio of the two sheets is between 1.5: 1 and 4: 1. 6. The method according to claim 3, characterized in that the wire mesh (5) has a width that is 5 - 40 ffi less than the total width of the Conveyor belt into which it is introduced. 7. The method according to claim 3, characterized in that for the Anchoring the wire mesh (5) in the structure of the belt on both sides of the Two strips of textile inlays are arranged on the tape, similar to that of the frame, each strip having a width of 25-30 ° p of the total width of the tape. 8. The method according to claim 3, characterized in that for the anchoring of the wire mesh (5), for the last inlay of the scaffolding, one on both sides 30 greater width is provided, which is over the grille or over the wing is placed in such a way that underneath on each side at least 10 ffi of Surface of the wire mesh (depending on the thickness of the wing) attached is, and that the wing either alone causes the anchoring of the grid or a special attachment is attached for this purpose.