Abstract: There is disclosed a handheld air flow velocity measurement probe that includes a bridge circuit assembly having an airflow velocity sensor that is a resistance temperature detector (RTD) and a digitally controlled resistive element to dynamically adjust and maintain the resistance of the velocity sensor within the overheat temperature predefined range. The velocity measurement also uses a separate temperature sensor to sense the temperature of the air or gas flow. A humidity sensor is also included remote from the other sensors to measure humidity in the gas flow to be measured. All of the above described components are housed at a probe tip instead of a base as in most standard handheld probes and the digital interface at the probe tip allows the user to replace a bulky, expensive telescoping antenna with stackable extender scheme.

Abstract: There is disclosed a handheld air flow velocity measurement probe that includes a bridge circuit assembly having an airflow velocity sensor that is a resistance temperature detector (RTD) and a digitally controlled resistive element to dynamically adjust and maintain the resistance of the velocity sensor within the overheat temperature predefined range. The velocity measurement also uses a separate temperature sensor to sense the temperature of the air or gas flow. A humidity sensor is also included remote from the other sensors to measure humidity in the gas flow to be measured. All of the above described components are housed at a probe tip instead of a base as in most standard handheld probes and the digital interface at the probe tip allows the user to replace a bulky, expensive telescoping antenna with stackable extender scheme.

Abstract: There is disclosed a handheld air flow velocity measurement probe that includes a bridge circuit assembly having an airflow velocity sensor that is a resistance temperature detector (RTD) and a digitally controlled resistive element to dynamically adjust and maintain the resistance of the velocity sensor within the overheat temperature predefined range. The velocity measurement also uses a separate temperature sensor to sense the temperature of the air or gas flow. A humidity sensor is also included remote from the other sensors to measure humidity in the gas flow to be measured. All of the above described components are housed at a probe tip instead of a base as in most standard handheld probes and the digital interface at the probe tip allows the user to replace a bulky, expensive telescoping antenna with stackable extender scheme.

Abstract: A system for measuring size segregated mass concentration of an aerosol. The system includes an electromagnetic radiation source with beam-shaping optics for generation of a beam of electromagnetic radiation, an inlet sample conditioner with adjustable cut-size that selects particles of a specific size range, and an inlet nozzle for passage of an aerosol flow stream. The aerosol flow stream contains particles intersecting the beam of electromagnetic radiation to define an interrogation volume, and scatters the electromagnetic radiation from the interrogation volume. The system also includes a detector for detection of the scattered electromagnetic radiation an integrated signal conditioner coupled to the detector and generating a photometric output, and a processor coupled with the conditioner for conversion of the photometric output and cut-size to a size segregated mass distribution.

Abstract: An apparatus and method for estimating size segregated aerosol mass concentration in real time and using a single detector. A beam of electromagnetic radiation is passed through a particle stream made of a test or field aerosol. The single detector outputs an electrical signal proportional to the electromagnetic radiation scattered thereupon. The electrical signal may be conditioned to produce an integrated signal for measuring radiation scattered from all the particles in the interrogation volume, a pulse height from an individual particle within the volume, and/or a time-of-flight measurement from the individual particle. The integrated signal can be correlated to particle mass concentration. The pulse height signal and the time-of-flight signal may be converted to infer the size of the individual particle. Attendant size distributions for the particle sizes may also be obtained. Using known or assumed particle properties, the mass concentration may be estimated from the size distribution.

Abstract: An apparatus and method for estimating size segregated aerosol mass concentration in real time and using a single detector. A beam of electromagnetic radiation is passed through a particle stream made of a test or field aerosol. The single detector outputs an electrical signal proportional to the electromagnetic radiation scattered thereupon. The electrical signal may be conditioned to produce an integrated signal for measuring radiation scattered from all the particles in the interrogation volume, a pulse height from an individual particle within the volume, and/or a time-of-flight measurement from the individual particle. The integrated signal can be correlated to particle mass concentration. The pulse height signal and the time-of-flight signal may be converted to infer the size of the individual particle. Attendant size distributions for the particle sizes may also be obtained. Using known or assumed particle properties, the mass concentration may be estimated from the size distribution.