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Feedback Control of Particles in Fluid Media.

PB97207195

Publication Date	1996
Personal Author	O'Shaughnessy, P. T.; Hemenway, D.; Haugh, L. D.
Page Count	99
Abstract	The reponse of environmental test chamber aerosol concentration levels to various changes in aerosol generator speed and chamber air flow rate was investigated. The use of statistical process control techniques to implement automatic feedback control of the instantaneous concentration levels by manipulation of the generator speed and dilution air flow rate was evaluated. A personal computer was used to control the output rate of an aerosol generator and air flow through the chamber, and was also connected to an aerosol monitor to record chamber aerosol concentrations. Trial results indicated no significant difference in the mean values of parameters used to describe the response of concentrations to a step change in generator output rate. Individual trial results indicated a broad range of responses about mean levels even when operating with the same conditions. A novel technique for disregarding much of the instantaneous variation was devised, based on the exponentially weighted average of the measurements. The method proved to be able to maintain chamber concentrations near a desired level and reduce both the total magnitude and number of corrections required to maintain concentratios near a desired level.
Keywords	Occupational safety and health Air quality monitoring Particles Grants Indoor air pollution Control technology Ventilation systems Feedback control Fluid media
Source Agency	National Institute for Occupational Safety and Health
Corporate Authors	Vermont Univ., Burlington. Dept. of Civil and Environmental Engineering.; National Inst. for Occupational Safety and Health, Cincinnati, OH.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
Title Note	Rept. for 1 Apr 94-31 Mar 96.
NTIS Issue Number	199724

Feedback Control of Particles in Fluid Media.

Feedback Control of Particles in Fluid Media.
PB97207195

Publication Date	1996
Personal Author	O'Shaughnessy, P. T.; Hemenway, D.; Haugh, L. D.
Page Count	99
Abstract	The reponse of environmental test chamber aerosol concentration levels to various changes in aerosol generator speed and chamber air flow rate was investigated. The use of statistical process control techniques to implement automatic feedback control of the instantaneous concentration levels by manipulation of the generator speed and dilution air flow rate was evaluated. A personal computer was used to control the output rate of an aerosol generator and air flow through the chamber, and was also connected to an aerosol monitor to record chamber aerosol concentrations. Trial results indicated no significant difference in the mean values of parameters used to describe the response of concentrations to a step change in generator output rate. Individual trial results indicated a broad range of responses about mean levels even when operating with the same conditions. A novel technique for disregarding much of the instantaneous variation was devised, based on the exponentially weighted average of the measurements. The method proved to be able to maintain chamber concentrations near a desired level and reduce both the total magnitude and number of corrections required to maintain concentratios near a desired level.
Keywords	Occupational safety and health Air quality monitoring Particles Grants Indoor air pollution Control technology Ventilation systems Feedback control Fluid media
Source Agency	National Institute for Occupational Safety and Health
Corporate Authors	Vermont Univ., Burlington. Dept. of Civil and Environmental Engineering.; National Inst. for Occupational Safety and Health, Cincinnati, OH.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
Title Note	Rept. for 1 Apr 94-31 Mar 96.
NTIS Issue Number	199724