Capture efficiency of pollutants in a free space and over a workbench with reinforced slot exhaust systems

Capture efficiency of pollutants in a free space and over a workbench with reinforced slot exhaust systems

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The slot reinforced exhaust system (known as REEXS) is a traditional slot exhaust hood equipped with an air supply inlet that intensifies exhausting along the axis of the exhaust hood. The experimental exhaust system can be configured in different ways. It can operate in traditional or reinforced exhaust modes. The article compares the capture efficiency of pollutants in a free space and over a workbench in front of reinforced slot exhaust hood. Comparisons are made for the same air velocity in the suction slot and with different momentum flux ratio of supplied and exhausted air flow. For capture efficiency measurements of this system, the tracer gas method is used. In this method a suitable gas is supplied in front of the exhaust hood and the concentration in exhausted air is simultaneously measured with a multi-gas monitor. As a tracer gas the carbon dioxide was chosen. From the measured concentration of tracer gas in the exhaust pipe the capture efficiency of investigated system is calculated. Knowledge of the shape and range of effective exhaust area for various configurations in front of the exhaust hood is important for setting the exhaust hood according to a source of pollutants.

The slot reinforced exhaust system (known as REEXS) is a traditional slot exhaust hood equipped with an air supply inlet that intensifies exhausting along the axis of the exhaust hood. The experimental exhaust system can be configured in different ways. It can operate in traditional or reinforced exhaust modes. The article compares the capture efficiency of pollutants in a free space and over a workbench in front of reinforced slot exhaust hood. Comparisons are made for the same air velocity in the suction slot and with different momentum flux ratio of supplied and exhausted air flow. For capture efficiency measurements of this system, the tracer gas method is used. In this method a suitable gas is supplied in front of the exhaust hood and the concentration in exhausted air is simultaneously measured with a multi-gas monitor. As a tracer gas the carbon dioxide was chosen. From the measured concentration of tracer gas in the exhaust pipe the capture efficiency of investigated system is calculated. Knowledge of the shape and range of effective exhaust area for various configurations in front of the exhaust hood is important for setting the exhaust hood according to a source of pollutants.

The slot reinforced exhaust system (known as REEXS) is a traditional slot exhaust hood equipped with an air supply inlet that intensifies exhausting along the axis of the exhaust hood. The experimental exhaust system can be configured in different ways. It can operate in traditional or reinforced exhaust modes. The article compares the capture efficiency of pollutants in a free space and over a workbench in front of reinforced slot exhaust hood. Comparisons are made for the same air velocity in the suction slot and with different momentum flux ratio of supplied and exhausted air flow. For capture efficiency measurements of this system, the tracer gas method is used. In this method a suitable gas is supplied in front of the exhaust hood and the concentration in exhausted air is simultaneously measured with a multi-gas monitor. As a tracer gas the carbon dioxide was chosen. From the measured concentration of tracer gas in the exhaust pipe the capture efficiency of investigated system is calculated. Knowledge of the shape and range of effective exhaust area for various configurations in front of the exhaust hood is important for setting the exhaust hood according to a source of pollutants.

Industrial ventilation, REEXS, exhausting, slot exhaust hood, tracer gas method, capture efficiency.

Industrial ventilation, REEXS, exhausting, slot exhaust hood, tracer gas method, capture efficiency.

03.09.2012

Swiss Federal Institute of Technology ETH Zurich

Zurich, Switzerland

ICCS 2012 International symposium on contamination control

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31–31

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