Method and apparatus for providing an antisticking layer on a band of bituminous roofing material

Abstract

 Method and apparatus for providing an antisticking layer on a band of bituminous roofing material manufactured by applying hot liquid bitumen to a band of carrier material, wherein the still hot band of bituminous roofing material is supplied to at least one cooled rotary cylinder, with an open-structured mat having been laid around the cooled cylinder, and with the mat having been provided with antisticking material and cooling liquid.

Description

[0001] The invention relates to a method and apparatus for providing an antisticking layer on a band of bituminous roofing material during the production thereof.

[0002] In the production of bituminous roofing material, normally in a continuous process first a suitable carrier or inlay, which may optionally be perforated, is impregnated with hot, liquid bitumen. Then, if desired, on one or both sides a bituminous coating can be provided. After further treatments, if any, such as, for instance, the calibration of the thickness of the produced band of roofing material using calibrating rollers, a band of roofing material is thus obtained, having a high temperature, which may be of the order of, for instance, about 160 to 210 °C. In any case, the band of roofing material has a temperature such that the bitumen of the roofing material is highly sticky. According to the known technique, a just produced band of roofing material is passed over a cooling cylinder which is internally provided with conduits through which flows cooling fluid. To prevent the roofing material from sticking to the cooling cylinder, it is customary to provide the roofing material, at least on the side proximal to the cooling cylinder, with a layer of chipping material, such as for instance sand, slate scales, flint chips, and the like.

[0003] A drawback of the use of chipping materials is that their application requires an additional processing step, which moreover requires special measures to prevent the chipping material spreading undesirably through the production hall. In this connection, it is further noted that the chipping material has a function not only as an antisticking layer, but also as a protective layer against the action of light if the roofing material has been fitted on a roof. This last function, however, is redundant when modern bitumen compositions (modified bitumen) are used.

[0004] Another drawback of the use of chipping material is that the operation of strewing it onto the band of roofing material should take place when the band is disposed in horizontal position. This means that the band must also be passed horizontally between the calibrating rollers which determine the thickness of the band. In doing so, the band of roofing material can hardly be prevented from sagging, as a result of which the coating will be thinner at the underside. Also, a horizontal path requires a great deal of production space compared with a vertical path, which can be used if the band does not have to be subjected to chipping.

[0005] The object of the invention is to obviate the drawbacks outlined above and generally to make available an efficient, reliable and readily applicable method and apparatus for providing an antisticking layer on a band of bituminous roofing material. To that end, according to the invention, a method for providing an antisticking layer on a band of bituminous roofing material manufactured by applying hot liquid bitumen to a band of carrier material is characterized in that the still hot band of bituminous roofing material is supplied to at least one cooled rotary cylinder, with an open-structured mat having been laid around the cooled cylinder, and with the mat having been provided with antisticking material and cooling fluid.

[0006] An apparatus for providing an antisticking layer on a band of bituminous roofing material manufactured by applying hot liquid bitumen to a band of carrier material is characterized, according to the invention, by at least one cooled cylinder drivable for rotation, which cylinder is provided with an open-structured mat embracing the cylinder, which mat is operatively disposed between the still hot band of roofing material and the cooled cylinder, as well as with means for supplying antisticking material and cooling fluid to the mat.

[0007] Hereinafter the invention will be further described with reference to the accompanying drawings of a few exemplary embodiments of an apparatus according to the invention.

Fig. 1 schematically shows an example of an apparatus for providing an antisticking layer on roofing material; and

Fig. 2 schematically shows a variant of the apparatus shown in Fig. 1;

[0008] Fig. 1 schematically shows a first example of an apparatus for providing an antisticking layer on a band of bituminous roofing material 1. In this example, the material band 1 is passed in vertical direction between two calibrating rollers 2, 3 to a cooled cylinder or drum 4. The calibrating rollers remove excessive bitumen off the material band and determine the thickness of the eventual roofing material. Just before the calibrating station, the material band has been provided with a layer of hot, liquid bitumen. It is noted that when using the configuration shown, with calibrating rollers in horizontal juxtaposition, between which the material band moves in substantially vertical direction, it is possible in a relatively simple manner, if desired, to impart an unequal thickness to the bitumen layers on opposite sides of the carrier. To that end, the system of calibrating rollers need only be moved to the left or to the right relative to the material band. The cooling cylinder 4 is provided with internal cooling conduits, not shown, through which, in operation, flows cooling fluid, so that the cooling cylinder 4 can cool the material band. Arranged between the cooling cylinder and the material band 1 is a mat 5 made of metal or a suitable plastic, which prevents the material band from contacting the cooling cylinder directly. The mat has an open structure and is operatively sprayed with an antisticking solution, which at the same time promotes the cooling of the material band. The mat can have, for instance, a woven structure and be formed from metal wire and/or plastic wire or can be a perforated material. During operation, the openings in the mat are filled with the antisticking solution.

[0009] The mat preferably forms a labyrinth between the cooling cylinder and the material band, so that vapor (steam) formed between the cooling cylinder and the material band can find a way out laterally. The steam is formed from the water of the antisticking solution if it contacts the hot (for instance 180 °C) surface of the material band. The fact that the steam can escape laterally prevents the steam pressure between the material band and the cooling cylinder from locally running up so high that bitumen is pressed away from the material band. This might jeopardize the watertightness of the end product.

[0010] The mat can be a jacket, thimble or sleeve arranged around the cooling cylinder, which is sprayed by a spraying device with antisticking liquid or is passed through a trough with antisticking liquid. In the example shown, the mat 5 has the form of an endless belt which has been passed over a roller 7 arranged above a receptacle 6 and extends around the cooling cylinder 4 via two auxiliary rollers 8, 9. In operation, the cooling cylinder 4 is driven for rotation by driving means, not shown, in the direction of the arrow 10. If desired, the roller 7 and/or the rollers 8 and/or 9 can also be driven. Denoted at 11 is a spraying device which can spray the mat 5 with a suitable antisticking solution. Such antisticking solutions are known per se and therefore will not be further described here. Excess antisticking liquid drips into the receptacle 6 and it can be returned from the receptacle to the spraying device again. Since the liquid dripping into the receptacle generally has a lower concentration of antisticking material than the solution initially sprayed by the spraying device, it is possible, in the receptacle and/or during the return of the antisticking solution from the receptacle 6 to the spraying device, to add additional antisticking material from a supply indicated schematically at 12, as indicated with an arrow 13. As already noted, the mat 5 can also be passed directly through the liquid in the receptacle 6, and this may or may not be combined with a spraying device.

[0011] During the contact between the material band 1 and the mat 5, the surface structure of the mat is pressed into the still soft bitumen layer of the material band. This is not a drawback and makes it possible, when using the roofing material, to see at a single glance which side of the material is the upper side.

[0012] After the material band 1 leaves the cooling cylinder 4 and the mat 5, as is the case at the arrow 14 in the example shown, any adhering liquid will evaporate as indicated at 15, leaving behind the solid parts of the antisticking solution on the material band. After leaving the cooling cylinder, the material band has cooled sufficiently to prevent the upper side of the material band, that is, the surface of the material band remote from the cooling cylinder, from sticking to subsequent rollers or drums. Of course, it is possible to cool the upper side of the material band directly as well, with an air stream or the like, as schematically indicated with arrows 16. It is also possible to provide the band downstream, after it has left the cooling cylinder, with a foil or film, or web, for instance a plastic film or chipping material, on the upper side thereof. Finally, the upper side could be passed over a cooling cylinder in a similar manner to the underside.

[0013] Fig. 2 shows an example of an embodiment of an apparatus according to the invention, in which a covering film or web is provided on the underside of the material band. In the embodiment of Fig. 2 a covering film 20 is fed between the material band 1 and the mat 5. In the example shown, the film 20 is passed from a supply roll 21 via the roller 8 together with the mat 5 around the cooling cylinder 4. Since the antisticking function is fulfilled by the film or the web, the liquid supplied by the spraying device 11 can be water. The film can be a film which is susceptible of melting, but which will be cooled sufficiently by the wet mat 5 so as not to melt upon contact with the hot bitumen of the material band 1. The heat given off by the bitumen layer is absorbed by the water present in the openings of the mat and on the mat, this water being converted to steam which is dissipated via the labyrinth described. The temperature thereby does not rise above about 105 °C and thus remains below the melting point of the covering film 20.

[0014] It is noted that after the foregoing, various modifications will readily occur to those skilled in the art. Thus, an apparatus according to the invention can, if desired, comprise several cooling cylinders arranged behind each other, enclosed with a mat provided with openings. Also, an apparatus according to the invention can be arranged for processing a material band supplied via a horizontal or inclined path. Further, as already noted, the antisticking solution could also be provided on the mat by selecting the liquid level in the receptacle 6 to be so high that the mat is passed through the liquid. The mat can be a jacket or thimble arranged around the cooling cylinder, but could also consist, for instance, of sintered material, for instance ceramic material, which has been provided on the surface of the cooling cylinder or forms part thereof.

[0015] Also, if desired, a film or web to be provided on the material band can be perforated.

[0016] These and similar modifications are understood to fall within the scope of the invention.

Claims

1. A method for providing an antisticking layer on a band of bituminous roofing material manufactured by applying hot liquid bitumen to a band of carrier material, characterized in that the still hot band of bituminous roofing material is supplied to at least one cooled rotary cylinder, with an open-structured mat having been laid around the cooled cylinder, and with the mat having been provided with antisticking material and cooling fluid.

2. A method according to claim 1, characterized in that the band of roofing material is supplied from a calibrating device for the thickness of the roofing material to the cooled cylinder substantially in vertical direction.

3. A method according to claim 1 or 2, characterized in that the antisticking material is supplied in the form of an antisticking solution which also serves as cooling fluid.

4. A method according to claim 1 or 2, characterized in that the antisticking material is supplied in the form of a film or web supplied between the mat and the band of roofing material, with the mat being wetted with cooling fluid.

5. A method according to any one of claims 1-4, characterized in that the mat is a jacket arranged around the cooled cylinder.

6. A method according to claim 5, characterized in that the jacket has been formed from sintered material.

7. A method according to any one of claims 1-4, characterized in that the mat is a belt-shaped endless mat, which has been laid around the cooled cylinder and a return roller.

8. A method according to claim 7, characterized in that the mat is sprayed with liquid in a path located between the cooled cylinder and the return roller.

9. A method according to any one of the preceding claims, characterized in that the mat forms a labyrinth which enables lateral dissipation of vapor between the cooled cylinder and the band of roofing material.

10. A method according to any one of the preceding claims, characterized in that on the side of the band of roofing material remote from the cooled cylinder a web or film layer or chipping material is provided, after the band has left the cooled cylinder.

11. An apparatus for providing an antisticking layer on a band of bituminous roofing material manufactured by applying hot liquid bitumen to a band of carrier material, characterized by at least one cooled cylinder drivable for rotation, which is provided with an open-structured mat lying around the cylinder, which mat is operatively disposed between the still hot band of roofing material and the cooled cylinder, as well as with means for supplying antisticking material and cooling fluid to the mat.

12. An apparatus according to claim 11, characterized in that the mat is a belt-shaped mat disposed around the cooled cylinder and a return roller.

13. An apparatus according to claim 11 or 12, characterized in that the mat is composed with the aid of suitable wire material.

14. An apparatus according to claim 11 or 12, characterized in that the mat comprises perforated material.

15. An apparatus according to claim 11, characterized in that the mat comprises a jacket disposed around the cooled cylinder.

16. An apparatus according to claim 11, characterized in that the mat comprises a sintered layer provided on the cooled cylinder.

17. An apparatus according to any one of claims 9-16, characterized in that the open structure of the mat forms a labyrinth which enables lateral dissipation of vapor between the band of roofing material and the cooled cylinder.

18. An apparatus according to any one of claims 9-17, characterized in that the means for supplying antisticking material to the mat comprise a spraying device operatively spraying antisticking solution on the mat.

19. An apparatus according to any one of claims 9-18, characterized in that the means for supplying antisticking material to the mat comprise a trough with antisticking liquid, through which trough the mat is passed.

20. An apparatus according to any one of claims 9-19, characterized in that the means for supplying antisticking material to the mat comprise a supply device for a film or web, which supply device supplies the film or the web to the mat before the band of roofing material contacts the mat.

21. An apparatus according to any one of claims 9-20, characterized by a receptacle for liquid dripping off the mat and by means for returning the liquid received in the receptacle to the spraying device.

22. An apparatus according to claim 18 and any one of claims 11-17, 19, 20 and 21, characterized in that the spraying device is arranged between the cooled cylinder and the return roller.

23. An apparatus according to any one of claims 11-22, characterized by a device for providing, downstream of the cooled cylinder, a web, a film or chipping material on the side of the band of roofing material remote from the cooled cylinder.

24. Roofing material manufactured using an apparatus according to any one of claims 11-23.

Drawing