Production line for bitumen cakes

This invention relates to a production line for bitumen cakes,

It is known to produce oxidized bitumen cakes or pigs by casting a mass of hot bitumen directly into bags formed from a special paper variety and being held within suitable containers which perform the function of molds for the bitumen being solidified in the paper bags. Other methods currently practiced provide for direct casting of hot bitumen into suitable cardboard drums or drums of any other suitable materials.

Also known is to cast hot liquid bitumen into metal containers having a vertical main dimension (i.e. very deep and narrow), which include several component parts and have a bottom which can be opened. Such containers are intended for receiving fluid hot bitumen and serving as solidification molds for the bitumen poured therein while being cooled either through elongate water tanks or through a forced ventilation tunnel. As they emerge out of the cooling tanks or tunnel, the formed bitumen cakes are removed from the containers and then packaged in paper bags or drums.

However,conventional systems for the production of bitumen cakes have some serious disadvantages both from a technical standpoint and of the investment involved in their manufacture and installation and of the system maintenance costs. In so far as the technical aspect is concerned,experience has shown that currently used systems incorporate excessively complicated devices which are liable to frequent failures that affect the production output in a drastic way. Moreover, conventional systems require very long cooling lines, which are accordingly very expensive and cumbersome, and thus they occupy large floor areas.In addition, even systems of more recent design present serious shake-out problems in that the cakes cooled within the metal containers cannot be removed in spite of the action of ultrasound, infrared beams, and mechanical ejectors having been utilized. Frequently, breakage of the metal container occurs before the bitumen cake solidified therein can be shaken out by the ejector.

It is an object of the present invention to provide a novel production line for the production of bitumen cakes, which makes it possible to solve or substantially eliminate the problems connected with the automatic shaking out of the bitumen cakes, in a simple and economical way.

Another object of the invention is that the said ^pro- duction line has a much reduced size over conventional systems, is highly reliable, and has relatively low running costs.

It is another object of the invention that said pro- auction line has no labor requirements for its operation, and is advantageous both by virtue of its high hourly and daily outputs and of its comparatively low manufacturing and installation costs.

These and other objects, are attained by a production line for bitumen cakes, which comprises, arranged sequentially, a casting station whereat hot bitumen is cast in pans or basins, a cooling station whereat the bitumen in the pans is cooled to yield bitumen cakes, a cake shake-out station, and a cake packaging station, and is characterized in that it comprises a plurality of pans whose width far exceeds their depth and being carried in groups on a plurality of supporting frames designed to . pass cyclically through said casting, cooling, and shake-out stations; and in that said cake shake-out station comprises an extraction device having a pusher arranged to act on the outside of the bottoms of said pans to produce resilient deformation of said pan bottoms, whereby said pans are caused to separate from a respective bitumen cake contained therein.

Further aspects and advantages of the invention will be more clearly understood from the following detailed description of a preferred, though not limitative, embodiment of a production line according to the invention, with reference to the accompanying drawings, in which:

• Figure 1 is a diagrammatic perspective view, taken slightly from above, of a production line according to the invention;
• Figure 2 is a top plan view of a pan or mold;
• Figure 3 is a sectional view taken along the line III-III of Figure 2;
• Figure 4 is a sectional view taken along the line IV-IV of Figure 2;
• Figure 5 is a bottom view of a pan-carrying frame or platform;
• Figure 6 is a front elevational view of the platform of Figure 5;
• Figure 7 is a side elevational view of the platform of Figure 5;
• Figure 8 is a bottom view of a platform provided with side-mounted wheels;
• Figure 9 is a front elevational view of the platform of Figure 8;
• Figure 10 is a side view of the platform of Figure 8;
• Figure 11 is a side elevationnel view of a pusher device incorporated to the shake-out station;
• Figure 12 is a reduced scale, sectional view of the device of Figure 11, taken along the line XII-XII;
• Figure 13 is a front elevational view of a suction cup knockout apparatus;
• Figure 14 is a side view of the knockout device of Figure 13;
• Figure 15 is a diagramma tic front elevation view of a metering dispenser apparatus for bitumen casting;
• Figure 16 is a side view of the apparaatus of Figure 15;
• Figure 17 is a top view of the appatatus of Figure 15; and
• Figure 18 is a diagrammatic side elevation view of a loader-unloader apparatus the pan-carrying frames or platforms.

With reference to the Figures of the accompanying drawings, it may be seen that the production line in Figure 1 for obtaining bitumen cakes includes a plurality of processing stations scattered sequentially along a processing path. More specifically, the production line essentially comprises a bitumen casting station 1, a bitumen cake cooling station2,a cake shake-out station 3, a cake packaging station 4,and a palletizing station 5 for the packaged cakes. All of the processing stations; 1 to 5 operate in a fully automated manner, thepro- duction line being de signed to be controlled by a single operator facing a control console 6. Casting at the station 1 takes place intermittently into four pans or basins 7 at a time (Figures 1 to 4). The pans 7 are carried in groups of twelve on a pan-carrying or support frame or platform 8 (Figures 5 to 10), which keeps them divided into three rows of four pans each.

The pans 7 have a flanged rim 9 which extends continuously along the entire periphery of the respective pan and is radiused at the corners. The sidewalls of each pan 7 are flared out to facilitate the removal of the bitumen cakes solidified there in The bottom 10 of the pans is spanned by two straight recessed ribs or beads 11 crossing each other to an "X", which have the dual function of ._stiffening and facilitating separation from the bitumen cakes cast and cooled within the pans, as will be explained hereinafter.

Advantageously, all of the pans 7 are applied a permanent anti-adhesion inner coating (not shown) comprising a silicone paint, such as a product available on the market under the trade name of Rhodorsil Silicones and produced by the French firm Rhodorsil, Paris (France). Advantageously,prior to casting, the pans 7 may be sprayed internally (at least for a certain number of casts, while the pans are still new and the anti-adhesion coating has yet to "settle") with a non-acidic anti-adhesive or parting agent, such as a suitable soapy emulsion, or a silicone-based product.

As may be noted, the pans 7 have a horizontal main dimension, in the sense that they are relatively shallow with respect to their length and width dimensions. All this is directed to enable the bitumen, once solidified, to part readily from the pan walls by having a minimum surface area of contact therewith, its top larger area surface being left quite free.

. Provided in the system shown are, for example, 4,056 pans 7 of pressed sheet metal, which are carried in groups of 12 on specially provided platform 8, to a total of 338 platforms. Most of the platforms are equal in size and construction to the platform shown in Figures 5 to 7, some other platforms being identical to the platform shown in Figures 8 to 10. The platform shown in Figures 5 to 7 has a grid structure defining twelve receptacles for accommodating as many pans 7 which, as mentioned, bear on the platform along their flanged rims 9. Provided at the four corners of the platform 8 are, at the top, four inclined guides 12, and at the bottom, four vertical legs or spacers 13 which, during the piling step, are arranged to slide and locate themselves inside the guides 12 of an underlying platform (as will be explained hereinafter). Each platform or frame 8 is provided on the bottom side with two pairs of rollers 14 aligned in the platform direction of movement and arranged to roll along rails or runways 15 (Figures 1,,13 and 14).

The frames or platforms 8 of Figures 8 to 10 may be, as an example, thirteen in number, and compared to the other platforms, have in addition strengthened oversize side panels and four side-mounted wheels 16 intended for rolling along rails 17 (Figures 1 and 18). Figures 11 and 12 illustrate a pusher assembly 19 located at the shake-out station 3. The assembly 19 comprises four pawls 20 mounted in pairs on a rigid support quadrangular structure 21 which is journalled for rotation about a horizontal axis 22. Each support structure 21 is provided, in the proximities.of the pawls 20, with a lug 23 extending downwards and having a bore 24. The lugs 23 are intended for articulation to one end of a respective actuator jack (not shown), which other end is articulated, through a bracket 25, to the frame of the station 3. As a platform 8 is being carried to overlie the four pawls 20 such that the latter are located approximately at the middle of the bottom of a respectiverow of four pans 7, it becomes possible to impart a resilient deformation on the pan bottom 10 by operating the actuator jacks of the supporting structures 21. More specifically, the bottom 10 of the pans is progressively urged upwardly by the pawls 20, to forcibly separate a bitumen cake 26 contained in each pan away therefrom, while the pans are being held in position on the platform 8 by detent rollers 27, shown in Figures 13 and 14, which are designed to act on the four corners of each pan 7.

Above the structures 21 and within the station 3, there is located an extiaction apparatus 30 with a double carriage 31 and 32 which can be displaced vertically on wheels 33 by an upright jack 34, and crosswise on wheels 35 by a horizontal jack 36 (Figures 13 and 14). Extending downwardly from the carriage 3₁ are a set of four suction cups 37, which are preferably spring loaded and are so aligned as to be centered over a row of four cakes 26 lying in as many pans 7.

Once a platform 8 has been moved along the rails 15 by a drive chain 38 engaging with a lower projection 39 on the platform (Figure 13), such as to bring a respective row of four pans 7 above the pawls 20 and under the suction cups 37, first the carriage 31, and hence the suction cups 37, will be lowered onto the surfaces of the bitumen cakes 26. Simultaneously therewith, the carriage 31 will actuate two side levers 40 and 41, which are each journalled at 42 on the stationary structure of the station 3 and have their top ends fitted with a roller 43 arranged to abut against the carriage 31 and the other ends articulated to a roller 27. The axle of the roller 27 is connected, via a linkage rod 44, to a second end roller 27 depending from the end of an arm 45 journalled at 46 to the stationary structure. The levers 40 and 45 form, together with the rod 44, and articulated parallelogram structure that is controlled by the roller 43 which, as the carriage 31 is lowered, will ensure good contact of the side rollers 27 with the edges of the outermost pans 7 in a row on the platform 8.

With the carriage 31 lowered, the pushers 20 are first brought into action on the bottoms of the basins or pans 7 in a row located beneath the carriage 31, thereafter the suction cups 37 are connected to a vacuum source (not shown) to take hold of the underlying bitumen cakes 26. Should any one hold be less than positive, e.g. if one suction cup 37 fails to make a vacuum-tight seal with the surface of the respective cake 26, then the whole extraction apparatus will stop (owing to the action of control means not shown) until the leaky condition has been corrected. However, if all four of the suction cups 37 engage positively, the carriage 31 will be raised by the jack 340 Thereafter, the jack 36 is brought into action which will move the carriage 32 in a horizontal direction until the suction cups 37, with the cakes 26 attached to them, are taken above a track-type side conveyor 45 onto which the suction cups will drop the cakes 26 (Figures 1 and 14) for their removal. The same sequence of operations is repeated for each of the three rows of pans on each platform 8.

The drive chain 38 for the platforms 8 is run both through the shake-out station 3 and through the casting station 1. Thus,while at the station 3 a row of four cakes 26 is being shaken out, it may be arranged for the casting, at the station 1, of liquid bitumen into four pans 7 placed on a platform 8 which has already moved out of the station 3.

The casting station 1 incorporates a metering- dispenser device 46 (Figures 1 and 15 to 17), which comprises a pre-metering vessel 47, which is fed through a limiter valve (not shown) with liquid bitumen from a bitumen source, generally in the form of an insulated line 48 as shown in Figure 1. Provided on the interior of the vessel 47 are a set of three diaphragms or partitions 49, which are mounted movable in a vertical direction and are spaced apart from one another. The partitions can, through a linkage generally indicated at 50 in Figures 15 and 17, be raised and lowered from/into the vessel 47 by means of a jack (not shown). As the vessel 47 is filled up with liquid bitumen, the partitions 49 are held in the raised position to favor a complete and even filling of the vessel 47. Thereafter, they are lowered to volumetrically divide the bitumen poured into the vessel 47 into four equal parts. The vessel 47 is provided at the top with a fume suction fan 51 and with a loading cell 52. The vessel 47 preferably incorporates, on one side thereof, a safety warning mechanism, generally indicated at 53, which has the function of stopping the system in the event of failure to fill or incomplete filling of the vessel 47. The vessel 47 is communicated between the partitions 49 to four infusion devices 54 having all the same inside volume and being provided at the bottom with a respective pouring valve 55 and actuator 56. Both the infusion devices 54 and vessel 47 are lined with a jacket 56 wherethrough a hot fluid is flown via a piping system 57 to keep the bitumen within the metering dispenser 46 in a liquid state (150-200°C). The device 46 is preferably guided vertically by rigid arms 58 mounted cantilever-fashion and having at the top three balls 59.

After completion of three consecutive casting operations or cycles by the device 46 and three corresponding forward movement steps by one platform 8, the latter leaves the casting station 1 and is driven by the chain 38 to advance stepwise along the rails 15 until it moves past an elevator-translator apparatus 60 (Figures 1 and 18).The appatus 60 comprises two spaced-apart supporting structures 61 and 62, on which a vertical framework 63 is mounted slidably which can reciprocate between the structures 61 and 62. counted on the framework 63 for sliding movement in a vertical direction is a table 64 equipped with two side gripper jaws 65, e.g. of a pneumatically operated type, for gripping the platforms 8.

The appatus 60 is arranged to sequentially lift the platforms 8 carrying pans 7 filled with bitumen thereon and transport them from the supporting structure 61 to the structure 62, and stack them one on top of the other in stacks or piles 66 containing for instance twenty five platforms each (Figure 1). Of coarse, the arrangement of the platforms 8 is such that at the beginning of each stack there occurs a platform 8 equipped with side-mounted wheels 16 for rolling along the rails 17. Once a stack 66 has been completed, it is caused to advance along the rails 17, e.g. by means of a step jack (not shown).

The rails 17. extend, as an example, through an air cooling tunnel or through a cooling-letting-down area, either in the open air or possibly under forced air circulation, such as by operating one or more blower sets 67.

It will be noted that the stacking of the platforms 8 is facilitated by the provision of the guides 12 and legs 13 thereon, which also serve as spacer elements between any platform and the one directly underneath. Thus, between the various platforms there are created air gaps through which the heat from the bitumen in the pans can be released and, if desired, an airflow may be forced. The provision for stacking the platforms 8 not only affords an effective cooling of the bitumen with simple and inexpensive means, but also a considerable reduction, over prior systems, in size and space requirements for the solidification of the bitumen, with attendant self- evident benefits both of a technical and economical nature.

At the outlet end of the tunnel or cooling area, there is provided a second elevator-translator appamtus 68, wholly similar to the apparatus 60 and, consequently, no further described herein. The device 68 is arranged to pick up, one by one, the platforms 8 from the foremost stack and again transport them along the rails 15 for feeding into the shake-out station 3.

The cakes 26, following their removal from the pans 7 and transferrment onto the conveyor 45, are delivered to a packaging station (Figure 1) which comprises a wrapping machine 70 operative to package each cake 26 by wrapping in one or more sheets of a heat shrinkable and extensible plastic material. The machine 70 is followed by a kiln 71, wherein the heat shrinkable material is caused to adhere by heat application onto the cakes 26. The cakes 26 leave the kiln 71 in a packaged condition and may be passed to a palletizing station 5.

A system like the one discussed above can afford, for example, a daily output of 100 tonnes of packaged cakes under the supervision of a single operator, who would only interfere in the event of malfunctions, plus one person in charge of the palletizing station.

The cakes 26^-, for example, may have a weight of 25 kg each, and a parallelepipedal shape measuring approximately 600×400×125mm,and be packaged in a thin film of heat shrinkable and extendible polyethylene.

The system just described is susceptible to many modifications and variations.

Thus, as an example, instead of a suction cup knockout device, provision may be made at station 3 for turning the pans 7 upside down after the cake contained therein has come unstuck from the pan walls owing to the action of the pushers 20. Of course, the materials and dimensions may be changed to meet individual applicational requirements.