**3. Recent developments**

As seen in the state of the art, most systems are based on torches. The devices described above present a series of disadvantages. The main ones are an excessive weight, and the fact that they are used for very specific tasks (some only serve to fix the overlaps, and others precisely do not seal the overlaps well).

To overcome all previous limitations from **Table 1**, two novel prototypes have been designed, simulated, and tested with torches and radiators as heating devices. Heaters are fixed to a lightweight structure, which can be pushed forward by an operator, and which unfolds the roll as it heats up, with emphasis on the overlaps. The efficiency of both systems is compared, and the speed of installation is determined.

#### **3.1 Infrared heating**

The patent protecting these novel equipment is P201830702 [16]—entitled "Lightweight mechanism for the rapid laying of bituminous sheets in flat roof waterproofing." A more in-depth analysis can be read in [17]. The mechanism is based on a trolley that allows a quicker installation of asphalt roofing rolls, in a cleaner and safer way than manual installation, by using infrared heaters. The worker does not need to lift the rolls because they are laid on the ground. As the worker advances, he pushes the trolley and the roll is unrolled helped by an auxiliary wheel. Eight infrared heaters are located longitudinally and radially around the roll, as can be seen in **Figure 3**. This layout provides a continuous and uniform heating of the roll, improving its adherence to the ground. Moreover, two drum rollers have been placed in the laterals of the trolley to ensure the adhesion on the overlaps.

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

**Figure 3.** *Design of the structure for the heaters [17].*

**Figure 4** shows the front, lateral, and top views of the design. The trolley (2) is pushed forward from the handle (1), whose height can be modified to suit the operator. The mechanism rests on four wheels (5) that allow the movement of the trolley. The rearmounted wheels are locked in the movement direction to help maintain the installation direction. The asphalt roofing roll (7) is located inside the structure. The trolley keeps the roll in the desired position with two locating stops (6). Besides, there is an auxiliary wheel (8), placed in the longitudinally center of the roll, and at an optimum height, which transmits the pushing force to the roll. This causes the rotation movement of the roll, facilitating its unwinding. Two small drum rollers (3) improve the overlapping.

**Figure 4.** *Front, lateral, and top views of the infrared heaters design [17].*

Al last, there are the eight infrared heaters (9) and the enclosure removable cover (10). A detail of the distribution of the heaters is also shown.

1200 W infrared heaters have been selected. The roll received a maximum power flux of 11,794 W/m2 . To determine the adequate heating up time for installing the first layer, a temperature selection choice was defined. On the one hand, the temperatures must be high enough along the external layer to bring most of the asphalt to a viscosity behavior point (140°C). But on the other hand, lower temperatures at the interlayer point are needed to avoid interlayer adhesion of the roll. Then, the top surface temperature must be much greater than 140°C, temperature must be at least 110°C at the middle section, and lower than 70°C the interlayer point. After 35 seconds of warming, the temperature is reached. Important to remark that when the installation begins, the operator has to pre-warm the roll for 32.5 seconds. **Figure 5** depicts the desired temperature profiles after heating for 35 seconds.

The time necessary to install the second and subsequent layers can be also calculated. After heating up of initial layer, the first–second interlayer temperature is 69.18°C. So, the heating up time for the second layer will be shorter because the layer is already preheated. As can be seen in **Figure 5**, after 2.5 seconds of warming, the outer surface of the roll is 69°C, the same temperature as the outer surface of the second layer at the end of the heating up time of the first layer. Thus, it will be needed to hold on for 32.5 seconds for raising the temperature of the following layer from 69 to 169°C. An average installation speed of 1 m/min, is demonstrated for 3 kg/m2 rolls. This means more than the current manual roofing rate, around 400–420 m2 per person a day.

Following the design and simulations, a prototype including infrared heater was assembled (**Figure 6**). The temperature criteria selected during thermal design were validated, and also the maximum temperature to prevent interlayer adhesions (below 60–80°C).

Finally, the equipment was tested outdoors. It was powered by a 14 kW diesel portable generator and pre-warmed for 2 minutes. Then, the installation began. One asphalt roofing roll was completely adhered to the ground, as shown in **Figure 7**. Approximately 8 m

**Figure 5.** *Temperature versus time of the top surface, middle section, and interlayer point of the roll [17].*

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

**Figure 6.** *Infrared heating prototype.*

**Figure 7.** *Outdoor installation test [17].*

of the asphalt roll were adhered after 8 minutes of warming, demonstrating the claimed installation speed.
