Development of a Chambered APD System
APP has developed a Chambered APD System as part of a Phase III SBIR with the U.S. Army. This work involved improving the performance of the elements of the APD System through development and experimental work and the production of a portable, chambered APD System.
The figure below illustrates the APD system's efficacy against bacterial endospores (B. atrophaeus) with two different chambers. While not as rapid as spot decontamination, a very high level of decontamination (6 logs) is achieved in only 24 minutes.
Figure 5. Graph showing the APD system's efficacy against bacterial endospores.
The Phase III efforts culminated with the development of a prototype APD Chambered System as shown in Figures 6 and 7. The prototype device consists of a 1 cubic foot treatment chamber, a plasma generator, a high-voltage power supply, an air system, a cooling system, exhaust filters and automated controls. These elements were combined into a complete APD system and packaged in a roll-around housing that is 3' deep by 4' wide by 6' tall. The system weighs approximately 900 lbs and requires approximately 4 kW of 3-phase, 208 VAC power when operating. Figure 7 is a front view of the APD system. The treatment chamber is visible near the center. The control panel is located to the right of the treatment chamber.
Figure 6. APD System General Concept.
Finally, the integrated APD system was evaluated by using it to neutralize samples (B. atrophaeus) placed in the decontamination chamber. It was able to achieve complete neutralization (more than 5 logs) of spore strips in 20 minutes using the APD plasma generator in the "hot mode" (80C) and in 35 minutes using the APD plasma generator in the "cold mode" (25C).
Figure 7. APD system photograph. (Front panel partially removed for illustration).
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