**2. State of the art**

There can be found several inventions to assist in the installation of asphalt coating, most of them based on one or more torches. In 1993, the patent ES 2041192 – entitled "Method and apparatus for applying a bituminous sheet to a substrate" [6] relates a preheated constant temperature roller (close to 300°C), wherein bituminous sheets slide toward their installation (**Figure 1**).

The patent DE-A 1652399-Device for heating and gluing a rolled material on a substrate [7] was published in 1971 (**Figure 2**). This patent claimed for a mechanism that allows the installation of a sheet by the application of heat to it. It includes a series of torches placed along all the bituminous sheet width. It has some disadvantages, for example, the direction of operator walking is backward, and this may cause falls from a certain dangerous height. Also, it prevents the operator from seeing what is happening behind his back, which could cause injury to other operators or apply the sheet on material remains causing fissures. Also, the heat application on the sheet is done from a great distance with respect to the installation point, and the bitumen primer that must be put on the substrate where the sheet is installed does not heat up. Moreover, the linear heating of the bituminous sheet causes that heat must be applied for a longer time, since it heats up from room temperature. Besides, there is only one general gas-regulating valve, which causes a perceptible pressure drop between the first torch and the last one. Last, the device could be too long, making it difficult to transport and place it on the construction site.

The patent US 4725328 [8]—a single ply roofing applicator, from 1988, presents the same characteristics commented for the previous mechanism, differing only in

**Figure 1.** *ES 2041192 patent design [6].*

**Figure 2.** *DE-A 1652399 patent design [7].*

two aspects. First, two torches are incorporated, placed perpendicular to the substrate, which are placed at both ends to promote adherence in the overlaps. Secondly, two rollers are added to each side of the mechanism to improve adherence to the overlaps by means of pressure against the substrate. It also shares some disadvantages with the previous mechanism, such as backward direction of operator walking, the linear heating of the bituminous sheet, and that there is only one gas-regulating valve.

In 1982, the patent US 4354893 [9]—combination roofing material unrolling and heat applying apparatus, was published. This patent describes a lighter design than the described above, since it dispenses with the roller system and the base to support the gas cylinder. It incorporates an extra handle, which permits the torches to get toward the roll as it unwinds, therefore enhancing heat application. As the previous ones, the direction of operator travel is backward, the warming is done from room temperature, that there is only one gas-regulating valve and, in addition, the unrolling system of the bituminous sheet is carried out by means of a bar incorporated into the axis of the roll. This is not efficient because the bituminous sheet is flexible and tends to deform. The appearance of folds that can cause problems for water filtration is favored.

Other significant patent is US2006037710 [10]—a membrane applicator. It varies in two aspects with respect to the previous patents: a gas cylinder is supported by a base,

*New Trends in Industrial Equipment for the Improvement of Asphalt Roofing Process DOI: http://dx.doi.org/10.5772/intechopen.101795*

and it includes the incorporation of a roller on one flank of the mechanism to guarantee the adherence of the overlap. Their downsides, again, are the reverse direction of travel, but also heat must be applied for a longer time since it heats up from room temperature, and to have only one gas-regulating valve, which is also a pitfall.

As well as patents, it is interesting to analyze what commercialized mechanisms exist. Among them, Seal-Master 1030 (Schäfer Technic GmbH) [11] is very relevant. It is a machine that allows the continuous installation of bituminous sheets in civil engineering works. It is mainly characterized by the large roller on which the bituminous sheet roll is placed for unwinding. This mechanism is not suitable for use on roofs due to its great weight and the use of sheets of greater length than those marketed for waterproofing roofs. It also incorporates a base to place the gas cylinder that is used to supply the torches that are located in the lower part of the mechanism. Finally, the roller used to ensure adherence of the bituminous sheet throughout its width also stands out. On the Schäfer Technic GmbH website, it is indicated that the weight of the set is 660 kg, which makes this mechanism not easy to transport. A site crane would be needed to raise it to the roof, and overload problems on punctual spots of the roof could seriously damage the structure of the construction.

Unify-ER (RES Automatisation Contrôle) [12] is characterized by its remote control (controlled by an operator) and by a greater number of mobile mechanisms than the rest of the systems, which makes this mechanism considerably increase in weight and makes it difficult to use on roofs. It also has a frame on which to place the


**Table 1.**

*Details of the characteristics to be improved in the different patents and commercialized products.*

gas cylinder, a system of rollers to improve the unrolling of the bituminous sheet, and some side stops that guide the roll and prevent folds from appearing when the sheet is placed on the substrate. It is based on the patent US 8887782—membrane applying apparatus, from 2014. The company claims for an installation speed of 1 m/ min, which means a rate of 18 rolls per hour employing two workers. This leads to an installation of 480 m<sup>2</sup> a day per person.

The principal drawbacks of these two systems are that they are too large to operate on small roofs, too heavy, and challenging to transport. In addition, they have an electronic and battery system, which increases the possibility of having failures that prevent the continued use of the device.

On the other hand, the devices FORSTHOFF-P2 (Forsthoff GmbH) [13] and BITUMAT B2 (Leister Technologies AG) [14] can be found. They only serve to heat the sheets in the overlaps, which is an essential requirement for a good waterproofing of the roofs, but they do not heat the rest of the sheet.

And finally, there is Bitumenbrenner (Bamert Spenglerei GmbH) [15], which allows the entire surface of the bituminous sheet to be heated as it uses four individualized torches equally spaced between them, spreading across the width of the sheet. This system also needs the heat to be applied for a longer time, since it heats up from room temperature, at least two operators are required (one of them unrolls the sheet while the other applies heat to it), and it does not allow a correct overlap between sheets, this being the most important process in the installation of waterproofing.

**Table 1** presents main characteristics of previous state-of-the-art semiautomatic roofing systems. **Table 1** includes those features that should be improved or changed.
