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Author: Chia-Chieh Yu, An-Yi Ma (2004-11-27); recommended: Yeh-Liang Hsu (2004-11-29).

Design of the 3rd generation prototype for DeIcer

This document describes the design of 3rd generation prototype for DeIcer based on the new burner provided by Fu-Ray. The outlet air speed is 3 m/s, and the temperature difference between inlet and outlet air reaches 80 degrees in about 2 minutes. The batteries and gas can will last for more than 1 hour. The dimensions of the prototype are approximately L140×W120×H160 mm, and the weight of the prototype is 1004g. This prototype and all related documents will be transferred to Fu-Ray for final product design.

1.     The new burner and gas can

Figure 1 shows the burner and ignition wire provided by Fu-Ray. The size of the burner is f28×10mm, which is much smaller than the previous burner we used in the 2nd generation prototype. The orifice of the burner is an important parameter for temperature rise between the input and output air of DeIcer. The orifice of the burner used here is f0.2mm As shown in Figure 1, the ignition wire is covered with ceramic material.

Figure 1. The burner and ignition wire

We also built a new gas can for the 3rd generation prototype to match with the new burner. Figure 2 shows that the new gas can that is thinner and taller. The outside dimension of the gas can is f46×48mm, and the volume of the gas can is 80 cm3, or 46.8g propane (the density of propane is 0.5853g/c.c). This gas can is designed to be re-filled.

Figure 2. The new gas can

2.     The flame housing design of the 3rd generation prototype

The critical component of DeIcer is the protective flame housing. The purpose of the protective flame housing is to keep the flame steady under the wind blown on it, to obtain complete burning, and keep the flame from coming out. The protective flame housing is also the heat source to heat up the air. Figure 3 shows the new design of the protective flame housing. This design has a cylindrical shape and can be mounted on top of the new burner.

Figure 3. The design of the protective flame housing

Figure 4 shows the explosive figure of the protective flame housing. There are 3 parts in the protective flame housing: the porous plate, the body, and the heat sink. The function of the porous plate is to release the hot exhausted air as part of the heat source. Four plates are used as “heat sink” to spread out the heat of the flame over the cylinder of the flame housing, so that the heat will not concentrate only on the top of the housing. These plates also separate the burning area with the porous plate where the exhaust air exits to keep the flame from coming out. Figure 5 shows the integration of the protective flame housing with the regulator and the new gas can. The engineering drawings are attached in Appendix A.

Figure 4. The explosive figure of the protective flame housing

Figure 5. The integration of the protective flame housing

3.     The blower

Figure 6 shows the blower provided by Raeider. The diameter of the fan is 50mm, which is smaller than the fan of a regular blow dryer (the one we used in the second generation prototype). The working voltage is 2.4V.

Figure 6. The blower

To measure its wind speed, we mounted the blower in a close plastic channel as shown in Figure 7. The blower was powered by two AA batteries (3V). Figure 8 shows that the wind speed of the blower decreases with time. After 30min., the wind speed was about 4.6 m/sec. In the 2nd generation prototype, the voltage required for the blower from a regular hairdryer was 6V, and the corresponding wind speed was over 3.5 m/s.

Figure 7. The experiment setup

MATLAB Handle Graphics

Figure 8. The performance of the blower

4.     The triggering mechanism and the blower

We modified the triggering mechanism of the stove provided by Fu-Ray from a mechanical one into an electronic one, and integrated with the switch of the blower. Figure 9 shows the integration of the triggering mechanism with the burner and the regulator. Figure 10 shows the electric circuit of the triggering mechanism. The operation of this triggering mechanism is a simple “push and turn”: push the knob to trigger the electrical arc, turn the knob to turn on the gas, then start the blower when the knob is turned to the end. There should be a safety device to prevent the knob from turning before pushing, so that there will not be gas explosion.

Figure 9. The integration of the triggering mechanism with the burner and the regulator

Figure 10. The electric circuit of the triggering mechanism

5.     Performance test of the 3rd generation prototype

Figure 11 shows layout of the 3rd generation prototype for DeIcer, and Figure 12 shows the final prototype. The dimensions are approximately L140×W120×H160 mm, and the weight of the prototype is 1004g. There are 8 components in this prototype: the burner, the protective flame housing, the regulator, the gas can, the blower, the triggering mechanism, the batteries, and the outer casing. The different arrows show the relation between the components. The ignition and the blower share 2 AA batteries. For demonstration purposes, the case of the prototype is made of transparent plastic, and the insulation materials are not installed.

Figure 11. Layout of the 3rd generation prototype for DeIcer

Figure 12. the 3rd generation prototype for DeIcer

The dimension of the slot for air outlet may affect the performance of DeIcer. Two slot dimensions are tested. Figure 13 shows the performance of the DeIcer using the slot dimension W55×H4 mm. The temperature difference reaches 80oC after 140 seconds and the outlet air speed is 2.3 m/s. Figure 14 shows the performance of the DeIcer using the slot dimension W47×H11 mm. The temperature difference reaches 80oC after 130 seconds and the outlet air speed is 3.0 m/s. This slot dimension is recommended. Note that the fuel used here is propane. A proper mixture of propane and butane should be used in the final product. We also measured the time that a full gas can will last. After one hour past, the burner was still burning.

Figure 13. The performance of the DeIcer (Slot W55×H4 mm)

MATLAB Handle Graphics

Figure 14. The performance of the DeIcer (Slot W47×H11 mm)

6.     Conclusion

The 3rd generation prototype for DeIcer is closer to the final product. The outlet air speed is 3 m/s, and the temperature difference between inlet and outlet air reaches 80 degrees in about 2 minutes. The batteries and gas can will last for more than 1 hour. The dimensions of the prototype are approximately L140×W120×H160 mm, which is suitable for a hand-held device. The weight of the prototype is 1004g, which is a little heavy for a hand-held device. Table 1 shows the weights of the individual components. The weight should be further reduced in the final document.

Table 1. Weights of the individual components

gas can

blower and  outer casing

burner and  protective flame housing

regulator

battery and circuit components

187g

225g

156g

207g

189g

This prototype and all related documents will be transferred to Fu-Ray for final product design.


Appendix A Engineering drawings of the protective flame housing