DE2916187C2 - Device for drying and heating tar- or bitumen-coated mineral mix - Google Patents

Description

The invention relates to a device for drying and heating tar or bitumen wrappings Mineral mixture, in particular for the recycling of bituminous road excavation material, with a The treatment chamber is traversed by hot gas pipes and in which the mixture is transferred by heat is heated and conveyed to a discharge opening.

The increasing shortage of crude oil and the imminent depletion of natural Asphalt stocks make it necessary to repair roads or other bituminous traffic areas that are old, destroyed or damaged To break up bituminous pavements and to prepare the excavated material and for the repair or the To use new building again. To get the demolition material back into a workable state move, it is necessary to shred coarse material and then to dry and heat to to liquefy the bituminous binder again and a processable, bituminous one? Mineral mixture too obtain.

However, the softening of the initially lumpy demolition material causes considerable difficulties because the supplied heat penetrates only slowly into the interior of the mostly relatively coarse material and because the material for liquefying the bitumen must be heated to a temperature at which volatile bitumen gases escape, which can ignite. There is also the risk that the bitumen starts to burn when heated and develops a foul-smelling, gray smoke, which pollutes and nuisances the environment to a great extent.

In order to avoid this disadvantage, in a known device of the type mentioned above (Magazine »Bitumen, H. 1/1978, pp. 22 and 23) that Demolition material heated in a rotating drum, with heating gases passing through the drum arranged pipes are passed, which the old asphalt material running in countercurrent through Heat heat transfer. In order to supply a sufficient amount of heat, it is necessary to have a great deal of it To arrange heating pipes inside the drum, so that the cross section remaining between the heating gas pipes is relatively small. That into the drum Filled, lumpy asphalt material therefore remains slightly hanging between the heating gas pipes at the end of the feed and blocks the cross-section of the passage. It also sits down on the hot gas pipes with

over time more and more asplialtmatenal, that like a Insulation works and severely impairs heat transfer. It also occurs by name on Discharge of the drum, where the particularly hot heating gases enter, easy to separate the softening, th, bituminous material.

The object of the invention is to provide a device of To create the type mentioned at the beginning, with which the mineral mixtures are promoted and raised without disabilities Such a high temperature can be brought that ι υ like a new one from bitumen and aggregates produced bituminous mix can be processed and installed.

This object is achieved according to the invention in that the heating gas pipes are located on the underside of ii several, one above the other arranged transport surfaces, each of which has at least one Has discharge point and on which the mixture can be conveyed along up to the discharge opening.

This configuration has the advantage that that too drying and heating bituminous mineral mixture on the one hand directly from the transport surfaces of heated from below and irradiated with heat from above, but at the same time compulsorily via the Transport surfaces is pushed so that it cannot stick to them.

Since several transport surfaces are stacked in the Treatment chamber are arranged, the residence time of the mixture to be heated in the treatment chamber is so long that a sufficient liquefaction The bitumen can also be achieved with lower heating gas temperatures than is the case with the known Device are required. Therefore hardly any vapors develop in the treatment chamber coking of the bitumen and the associated smoke development is definitely avoided.

According to a further feature of the invention, the heating gas pipes can be designed as flat hollow bodies be in contact with the transport surfaces or by them be limited. Here, the heating gas pipes have from the surface of the on the next lower transport surface lying mixture only a small distance. This training becomes an excellent one Heat transfer achieved from the heating gases to the mineral mixture.

To item mineral mix smelled more warmth feed, can also be arranged above the upper transport surface and / or laterally next to the transport surfaces heating pipes, which are slightly Distance from the mixture to be heated.

According to a further feature of the invention, the heating pipes arranged under two transport surfaces arranged one above the other are connected to one another. These pipes are taken one after the other by the Heating gases flow through and form heating coils, as it were, which are located on the transport surfaces moving material flow around the top, the bottom and one long side. The heating pipes run transversely to the conveying direction of the transport surfaces and form two pipe systems me, both in the middle of the treatment chamber a common heating gas source are connected and one of which is the upper half of the pipe system Treatment chamber in countercurrent to the mixture to be dried and of which the other M Pipe system the lower half of the treatment chamber in cocurrent with the mixture to be dried runs through. This arrangement has the advantage that that too warming mineral mixture neither at its point of entry into the treatment chamber nor at its The exit point is acted upon by very hot gases. At the same time, the heating gas guide in the upper Part of the treatment chamber, which takes place in countercurrent to the movement of the material, achieves the best possible heat transfer in order to move the material as quickly as possible to bring to a higher temperature. In the lower part of the In the treatment chamber, on the other hand, the ongoing stream of material no longer encounters gases that are getting hotter and hotter, but is approximately with it until it is discharged constant temperature, because it is important to have the mix to be heated over a exposure to heat for a longer period of time, so that the heat also extends into the interior of the approximately still can penetrate existing pieces of material.

The heating gas source can be a gas or oil burner arranged outside the treatment chamber, whose combustion chamber is located at a distance in front of the treatment chamber and the one with a cooling jacket is provided. The cooling jacket is from part of the The heating gases leaving the treatment chamber flows through, which are then mixed with the fuel gas and together with this can be fed back into the treatment chamber. This configuration has the Advantage that on the one hand the thermal energy generated by the burner is fully utilized, on the other hand the The temperature of the heating gases introduced into the treatment chamber is controlled and thus reduced can be that overheating of the bituminous material to be heated cannot occur.

So that no vapors or bitumen gases get into the atmosphere, the treatment chamber an extractor duct leading to the combustion chamber. This line leads to drying and heating of the mineral mixture any gases and vapors produced by combustion. These vapors will expediently withdrawn from the treatment room with a suction fan and directly into the flame of the Blown in the burner.

The transport surfaces used in the device according to the invention can be vibratory conveyors. However, it is particularly useful if the Conveyor troughs of Kra'z chain conveyors covered on the upper side by the hot gas pipes are, whose endless scraper chains run one after the other over several of the transport surfaces arranged one above the other. With such a training ensures that the mix to be heated does not stick to the transport surfaces heated from below or gets stuck because it is constantly being scraped off by the scraper bars or bars of the scraper chains is transported further. Furthermore, there is a particularly good heat transfer, since that to be heated Mixture is constantly circulated and loosened when it falls on the next lower transport surface and is transported on in the opposite direction.

It is particularly useful if the scraper chain of each scraper chain conveyor via a set of at least four transporters arranged one above the other = surfaces runs and if the dreams of scratches over Drive and reversing rollers are guided so that the scraper chain, after sweeping over the top transport surface, first to the bottom transport surface and then passes over the middle transport surfaces of the set before returning to the top transport surface. This configuration has the advantage that the

Scraper chain always alternates between hot and cold zones when sweeping over the transport surfaces, absorbs and carries with it small amounts of molten bitumen during transport work, which as Lubricant for the chains of the scraper chain works and special maintenance of the conveyor is superfluous power.

About the different elongation of the scraper chains due to the uneven heating To compensate for this, tensioning devices can be provided for the scraper chains.

The device according to the invention is explained with reference to the drawing. Fs shows

F i g. I the device in longitudinal section and

F i g. 2 the device according to FIG. I in cross section.

The device for drying and warming up empty or bitumen-coated mineral mixes, especially for reprocessing a broken one. b:!:, ': r, ::; ::'. c "SlraÜc" hc! :: "C", '■' ■ ',. :: your C; c.; :: "! h'j ;!:; ii!

10 denotes and consists essentially of one Treatment chamber 11 and a heating gas source 12. the arranged outside the treatment chamber 11 and with this through a conical heating gas nozzle 13 connected is. The treatment chamber 11 has a substantially rectangular shape and is provided with a insulating material 14 lined. Instead of this, the floor 15, the ceiling 16, the Longitudinal walls 17 and 18 and the end walls 19 and 20 themselves made of a heat-insulating and / or fireproof Material.

Inside the treatment chamber It are eight Transport surfaces 21, 22, 23, 24, 25, 26, 27 and 28 are provided, which are vertically spaced from one another are arranged and extend approximately horizontally in the longitudinal direction of the treatment chamber II. Here be! the top transport surface 21 at a distance from the ceiling 16 and the lowermost transport surface 28 away from the floor 15 of the treatment chamber II. The transport surfaces 21 to 28 consist of thick, wear-resistant steel plates, under which heating gas pipes 29, 30, 31, 32, 33,34,35 and 36 are arranged. These heating gas pipes consist of flat hollow bodies that over almost the entire length of the transport surfaces 21 to 28 extend and the top of which is formed by the thick steel plates, which the transport surfaces represent. The lower floor 37 and the end walls 38 and 39 of the heating gas duct consist of a thin, thermally conductive material, for example made of steel or copper sheet.

As shown in FIG. 2 are on the long sides of the transport surfaces 21 to 28 towering Seitenwändc 40 and 41 arranged, of which the side walls 40 on the longitudinal walls 17 and 18 of the treatment chamber

11 apply or are formed by these themselves and of which the side walls 41 at the same time heating gas connection lines 42 to the treatment chamber 11, which in the longitudinal side walls 17 and 18 the treatment chamber 11 are arranged and two heating gas pipes 29 and 30, respectively, lying one above the other or 30 and 31 or 31 and 32 or 32 and 33 or 33 and 34 or 34 and 35 or 35 and 36 with each other associate. This forms the transport surfaces 21 to 28 together with the side walls 40 and 41 and the lower floors 37 of the heating gas pipes 29 to 36 are closed conveyor troughs 43. only at their Front sides are open.

It can be seen from FIG. 2. that heating gas pipes 44 are also arranged under the ceiling 16 of the treatment chamber 11 and that the heating gas pipes 44 and 29 to 36 extend transversely to the conveying directions 45 and 46 of the transport surfaces 21 to 28. The heating gas pipes 44, 29, 30 and 31 in the upper half 47 of the treatment chamber and the meat gas pipes 33, 34, 35 and 36 in the lower half 48 of the treatment chamber each form a coherent pipe system A or B. The heating gas pipe 32 arranged in the middle of the treatment chamber 11 are connected to the heating gas nozzle 13 of the heating gas source 12. The heating gases entering the heating gas pipe 32 thus flow one after the other through the oil / gas pipes 31, 30, 29 and 44 of the upper pipe system and then exit through an outlet opening 49 in the upper part 47 of the treatment room into a Raucligasauszugleilung 50. Another sale of the leizgase slröml entering the leizgas pipe 32 through the leizgasrohre 33, 34, 35, 36 of the lower one

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48 of the treatment chamber 11 through a lower one Outlet opening 51 into the flue gas exhaust line 50.

As shown in FIG. I emerge, in the vicinity of the end wall 19 in the ceiling 16 of the treatment chamber 11, a material feed funnel 52 is arranged, which opens out above one end of the uppermost transport surface 21. A material discharge opening 53 is provided in the bottom 15 of the treatment chamber 11, approximately vertically below this material feeder 52, which contains a chute 54 which adjoins the end of the internal transport surface 28. The lumpy broken material poured by the material feeder 52 onto the uppermost inspection surface 21 is pushed by two scraper chain conveyors 55 and 56 over the transport surfaces 21 to 28 to the discharge opening 53 and is heated to approx. 180 during the passage through the processing chamber recognizes from Fig. I. that the transport surfaces or conveyor troughs 21 to 28, in which the Kratzketteförde rer 55 and 56 work, are replaced in the longitudinal direction against each other ν that the next lower lying transport surface protrudes compared to the transport surface lying above it in their longitudinal conveyor. for example, the Iran sports surface 22 jumps over the Transportflächc 21 in the conveying direction 45 via the endscitige end wall 39 by the dimension Oi before. during the Transportflächc 23 above the conveying surface 22 in their Transporlrichtung 46 by the same amount ei protrudes. Hereby, each transport surface having a Abwurfstclle 57 on the forehead cn finds. where the mixture is thrown on the transport surface from the chain scraper conveyor 55 or 56 on the next lower transport surface and is transported on there in the opposite direction.

'' Leather of the two scraper chain conveyors 55 and 56 consists of two plate-link chains 58 running along the side walls 40 and 41 of the conveyor troughs 43. which are connected to one another by scrapers 59, which are at the longitudinal distance of the chain from one another

¹ are arranged and brush over the transport surfaces 21 to 28 and take the mix lying directly on the heated channel bottom and push it along on the transport surfaces. Instead of a chain conveyor, a movable steel conveyor can also be used.

"Wire mesh can be used.

The Kra'.zerkette 58 is on every Kralzerkettenförder 55 or 56 in this way via drive rollers 60 and deflection rollers 61,62. 63,64 and 65 led that they according to

Passing over the hottest transport surface arrives at the coldest transport surface of the set of transport surfaces it has swept. The strands 66 of the scraper chain 58 of the upper scraper chain conveyor 55, which sweeps over the set X consisting of the transport surfaces 21, 22, 23 and 24, run from the uppermost, coldest transport surface 21 of the set over the sweeping rollers 61 and 62 and the drive roller 60 immediately to the lowest, warmest transport surface 24 of the set. Here, the scraper chain 58 changes its direction of travel and is then again guided over the middle transport surfaces 23 and 22 of the upper transport surface set, reversing the direction in each case, until it returns to the uppermost transport surface 2). This ensures that the transport chain, which has cooled down comparatively far when it comes into contact with the still-cold mix that has just been poured in. broken open again in the area of the lowermost transport surface and filled into the material feed hopper 52 in such a way that there is always material in the hopper. The bituminous mixture 100 sliding onto the uppermost transport surface 21 is carried along by the scraper 59 of the scraper chain 58 of the upper scraper chain conveyor 55 in the conveying direction 45 and pushed over the transport surface 21. Here, the mixture is heated over a wide area from below by direct contact with the transport surface heated from below and from above by radiant heat, which the heating gases flowing through the uppermost heating tubes 44 generate.

At the end of the transport surface 21, the bituminous mixture 100 falls onto the drop point 57 next lower transport surface 22, where it is again from the scraper chain 58 of the scraper chain conveyor 55 is detected and pushed in the conveying direction 46 over this transport surface until it reaches its discharge point 57

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absorbs components that act as lubricants and for the easy mobility of the chain links as the scraper chain continues through the Treatment room.

Similarly, the strands 66 of the scraper chain 58 of the lower scraper chain conveyor 56 become so around the pulleys 61, 62, 63, 64 and 65 and around the drive roller 60 that the chain of the uppermost, hottest transport surface 25 to the coldest transport surface 28 of the transport surfaces 25, 26, 27 and 28 existing lower transport surface set is performed, from where they then over the middle Transport surfaces 27 and 26 returns to the top transport surface 25 of the set V '.

The heating gas source 12 consists of a gas or oil burner 67, the combustion chamber 68 of which is arranged at a distance in front of the treatment chamber 11 and is connected to it by the heating gas nozzle 13 (FIG. 2). The walls 69 of the combustion chamber 68 are lined with refractory material 70 and surrounded at a distance by a cooling jacket 71 through which some of the heating gases 72 flow, which leave the treatment chamber 11 through the heating gas pipes 44 and 36. For this purpose, the annular space 79 formed by the cooling jacket 71, which surrounds the combustion chamber 68, is connected to the flue gas exhaust line 50 via a branch line 74 and is equipped with a suction fan 75. By means of this suction fan, part of the heating gases is drawn off from the flue gas vent 50 and passed into the annular space 79, where the flue gases, which have meanwhile cooled down, cool the combustion space 68. They are then passed into the heating gas nozzle 13, where they mix with the hot combustion gases 76 of the burner and lower their temperature so that the temperature of the heating gases entering the treatment chamber from the heating gas nozzle 13 does not significantly exceed ^{250 e C.}

In the upper half 47 of the treatment chamber 11 an extractor duct 80 is connected into which a Suction fan 81 is installed and so opens into combustion chamber 68. that the vapors and vapors withdrawn from the treatment chamber 11 are volatile Bitumen components are blown directly into the ram 82 of the burner 67 and burn there.

The mode of operation of the device is as follows:

The bituminous Mineraikonglornerat obtained by milling or breaking up a road or dg !, is initially to a grain size of <30mm nicuci

Here it is then transported again in the conveying direction 45 by the transport chain to the discharge point 57, where it falls onto the fourth transport surface 24. The process is then repeated in the area of the lower transport surface set Y, where the lower scraper conveyor 56 takes over the transport of the bituminous mixture 100 over the lower transport surfaces 25, 26, 27 and 28 until the bituminous mixture at the drop point 57 of the lowest transport surface 28 over the Chute 54 is discharged from the device.

All the way through the treatment chamber 11, the bituminous mixture is from below and above and from the sides through the in the heating gas pipes 44, 29 to 36 and 42 flowing Heating gases heated to a final temperature of 185 ° C, at which it emerges at the discharge opening 53. the Heating gases are generated in the combustion chamber 68 and mixed with the cooler heating gases from the flue gas outlet pipe 50 can be removed into which the heating gases emerging from the treatment chamber 11 escape. The volatile bitumen gases and vapors that are created when the mix is heated fed to the combustion chamber through the extractor duct 80 and burned in the flame 82.

Depending on the moisture and temperature of the bituminous mineral mixture to be heated, the The transport speed of the scraper chain conveyor and the burner output are controlled. Usually you want the transport surfaces have a temperature of 250 ° C and the layer thickness of the over the transport surfaces transported material should not significantly exceed 50 mm. The length of the entire path which the material back in the device is then chosen so that the mineral to be heated to the Discharge point a temperature of 180 ° to 185 ° C achieved.

In Fig. 1 are designated with 83 clamping devices, which keep the scraper chains 58 of the scraper conveyors 55 and 56 taut when they are in operation Warming change their length.

It is also possible for others to convey the bituminous mineral mixture through the treatment chamber Provide continuous conveyors that allow the unhindered access of heat to the to be dried Ensure material. For example, baffle plate conveyor, screw conveyor or Vibratory conveyors are used.

For this purpose 2 sheets of drawings

130 228/311

Claims (10)

Patent claims: 1. Device for drying and heating tar or bitumen coated mineral mixture, ins-> special for the reprocessing of bituminous road rubble, with a treatment chamber traversed by hot gas pipes, in which the Mixture is heated by heat transfer and conveyed to a discharge opening, thereby characterized in that the heating gas pipes (29 to 36) are located on the underside of several transport surfaces (21 to 28) arranged one above the other are located, each of which has at least one discharge point (57) and on which the mixture (100) can be conveyed along up to the discharge opening (53). 2. Apparatus according to claim 1, characterized in that the heating gas pipes (44, 29 to 36) as flat hollow bodies are formed, abut against the transport surfaces (21 to 28) or from these are limited and have a small distance from the surface of the mixture (100) lying on the next lower transport surface. 3. Apparatus according to claim t or 2, characterized in that above the top one Transport surface (21) and / or laterally next to the transport surfaces (21 to 28) heating pipes (44) are arranged, which are at a small distance from the to heating mixture (100) are located. 4. Device according to one of claims 1 to 3, ω characterized in that the transport surfaces (21 to 28) arranged Heizrohi-sr (29 to 36) with each other are connected. 5. Device according to one of Claims I to 4, characterized in that the heating pipes (29 to 36, 44) run transversely to the conveying direction (45 or 46) of the transport surfaces (21 to 28) and form two pipe systems (A and Sj, which are both connected in the middle of the treatment chamber (f I) to a common -to heating gas source (12) and of which one pipe system (A) the upper half (47) of the treatment chamber (11) in countercurrent to the mixture to be dried and of which the other pipe system (B) the lower half (48) of the treatment chamber (11) in cocurrent with the to be dried mixture (100) pulls through. 6. Device according to one of claims 1 to 5, characterized in that the heating gas source (12) a gas or oil burner (67) arranged outside the treatment chamber (U) is whose Combustion chamber (68) is located at a distance in front of the treatment chamber (11) and with a Cooling jacket (71) is provided. 7th Device according to one of Claims 1 to 6, « characterized in that the treatment duct (U) has a duct leading to the combustion chamber (68) Has extractor duct (80). 8. Device according to one of claims I to 7, characterized in that the transport surfaces (21 to 28) are vibratory conveyors. 9. Device according to one of claims I to 7, characterized in that the transport surfaces (21 to 28) from the heating gas pipes (44, 29 to 36) on the top covered conveyor troughs (43) from scratch <" are chain conveyors (55,56) whose endless scraper chains (58) are successively passed over several of the transport surfaces (21 to 28) arranged one above the other to run. 10. Device according to one of claims 1 to 9, characterized in that the scraper chain (58) of each scraper chain conveyor (55,56) via a set (X or Y) of at least four superposed transport surfaces (21 to 24 or 25 to 28) and that the strands (66) of the scraper chain (58) are guided over drive and reversing rollers (60 to 65) so that the scraper chain (58) first to the lowest after sweeping over the top transport surface (21 or 25) Transport surface (24 or 28) and then over the middle transport surfaces (22, 23 or 26, 27) of the set before it returns to the top transport surface (21 or 25).