Abstract: A parallel-plate diffusion gas dehumidifier has a treatment zone having at least one water-permeable membrane. The gas dehumidifier includes an untreated gas inlet, a treatment zone bounded by water-permeable membranes, a support structure for the membranes, access to a source of vacuum, and a dehumidified gas outlet. The cross section of the treatment zone may be provided in various shapes, for example, rectangular. The gas dehumidifier inlet and outlet include flow transitions that minimize the obstruction of particles passing through the dehumidifier. The dehumidifier may be used in particle sampling systems to dehumidify the sample gas prior to introducing the sample gas to a mass measuring device and mass flow controller. Methods of operating the gas dehumidifier and the particle sampling system are also provided.

Abstract: A sampling cartridge for a gas sampling apparatus includes a shell having a cylindrical wall and a sampling window extending through the wall. A pair of spools are coaxially and internally positioned within the shell. The spools are independently rotatable relative to the shell. A first spool may include multiple interval sample collectors while the second spool includes a duration sample collector. Each spool also has a window closing surface which is positioned adjacent the window whenever an access door of the gas sampling apparatus is opened. The sampling cartridge may also include a fully encapsulated section of sample collector material as a negative control, and an integral RF tag for storing chain of custody information including personal identification information of a cartridge replenisher.

Abstract: A high-flow rate, low-noise, gas sampling apparatus for collecting particulate such as biological, chemical, and radioactive material from a gas on a collector such as an impaction collector includes a housing having an inlet and an outlet and a fan disposed within the housing for drawing the gas into the inlet, past the collector for sampling, and exhausting the gas through the outlet. The fan is operable to produce a flow of gas through the housing of greater than about 50 liters per minute with a noise level emitted from the apparatus being less than about 60 decibels. The apparatus may be configured as a compact, unobtrusive, portable, lightweight apparatus for use in various indoor or outdoor locations. The apparatus may also include a sensor for the detection of radioactive material collected on the collector, a processor for monitoring the sampling, and the apparatus may be linked to a communications network such as the Internet. Methods for collecting particulate from a gas are also enclosed.

Abstract: A sampling cartridge for a gas sampling apparatus includes a shell having a cylindrical wall and a sampling window extending through the wall. A pair of spools are coaxially and internally positioned within the shell. The spools are independently rotatable relative to the shell. A first spool may include multiple interval sample collectors while the second spool includes a duration sample collector. Each spool also has a window closing surface which is positioned adjacent the window whenever an access door of the gas sampling apparatus is opened. The sampling cartridge may also include a fully encapsulated section of sample collector material as a negative control, and an integral RF tag for storing chain of custody information including personal identification information of a cartridge replenisher.

Abstract: A sampling cartridge for a gas sampling apparatus includes a shell having a cylindrical wall and a sampling window extending through the wall. A pair of spools are coaxially and internally positioned within the shell. The spools are independently rotatable relative to the shell. A first spool may include multiple interval sample collectors while the second spool includes a duration sample collector. Each spool also has a window closing surface which is positioned adjacent the window whenever an access door of the gas sampling apparatus is opened. The sampling cartridge may also include a fully encapsulated section of sample collector material as a negative control, and an integral RF tag for storing chain of custody information including personal identification information of a cartridge replenisher.

Abstract: A sampling cartridge for a gas sampling apparatus includes a shell having a cylindrical wall and a sampling window extending through the wall. A pair of spools are coaxially and internally positioned within the shell. The spools are independently rotatable relative to the shell. A first spool may include multiple interval sample collectors while the second spool includes a duration sample collector. Each spool also has a window closing surface which is positioned adjacent the window whenever an access door of the gas sampling apparatus is opened. The sampling cartridge may also include a fully encapsulated section of sample collector material as a negative control, and an integral RF tag for storing chain of custody information including personal identification information of a cartridge replenisher.

Abstract: A high-flow rate, low-noise, gas sampling apparatus for collecting particulate such as biological, chemical, and radioactive material from a gas on a collector such as an impaction collector includes a housing having an inlet and an outlet and a fan disposed within the housing for drawing the gas into the inlet, past the collector for sampling, and exhausting the gas through the outlet. The fan is operable to produce a flow of gas through the housing of greater than about 50 liters per minute with a noise level emitted from the apparatus being less than about 60 decibels. The apparatus may be configured as a compact, unobtrusive, portable, lightweight apparatus for use in various indoor or outdoor locations. The apparatus may also include a sensor for the detection of radioactive material collected on the collector, a processor for monitoring the sampling, and the apparatus may be linked to a communications network such as the Internet. Methods for collecting particulate from a gas are also enclosed.

Abstract: An air sampler having an automatic sample collector changer includes a supply magazine for holding a supply of fresh sample collectors and a receiving magazine for receiving and storing used collectors located aside a sampling station. A transfer mechanism transfers a fresh collector from the supply magazine to the sampling station and a used collector from the sampling station to an entrance of the receiving magazine. An automatic closer or plunger closes the entrance of the receiving magazine following transfer thereto of a used collector. The supply magazine can include an actuator for displacing a stack of sample collectors contained in said magazine. This stack may include interspersed air impervious covers. The transfer mechanism can transfer both a sample collector and a cover to the receiving magazine. Interspersing of covers with used sample collectors in the receiving magazine reduces volitization losses. For the same purpose, the temperature of the receiving magazine can be controlled.

Abstract: An air sampler having an automatic sample collector changer includes a supply magazine for holding a supply of fresh sample collectors and a receiving magazine for receiving and storing used collectors located aside a sampling station. A transfer mechanism transfers a fresh collector from the supply magazine to the sampling station and a used collector from the sampling station to an entrance of the receiving magazine. An automatic closer or plunger closes the entrance of the receiving magazine following transfer thereto of a used collector. The supply magazine can include an actuator for displacing a stack of sample collectors contained in said magazine. This stack may include interspersed air impervious covers. The transfer mechanism can transfer both a sample collector and a cover to the receiving magazine. Interspersing of covers with used sample collectors in the receiving magazine reduces volitization losses. For the same purpose, the temperature of the receiving magazine can be controlled.

Abstract: A carrier supporting multiple filters is inserted jointly with the filters into an air sampler. The carrier includes an indexing structure to ensure correct positioning within the air sampler. A memory device physically associated with the carrier stores sample collection data provided by the air sampler. The stored data can be read by a read/write station at a lab, and transmitted to a processor. The processor also receives a weight reading from a communicating balance for each collected sample, and calculates therefrom mass concentration for each sample.

Abstract: A carrier supporting multiple filters is inserted jointly with the filters into an air sampler. The carrier includes an indexing structure to ensure correct positioning within the air sampler. A memory device physically associated with the carrier stores sample collection data provided by the air sampler. The stored data can be read by a read/write station at a lab, and transmitted to a processor. The processor also receives a weight reading from a communicating balance for each collected sample, and calculates therefrom mass concentration for each sample.

Abstract: An airborne particulate sampling monitor for collecting particulate in either a solid, liquid or gaseous state. The monitor includes at least two intakes, each of which accepts airborne particulate. Paired with and coupled to each intake is an appropriate particulate filter for sampling accepted airborne particulates. A vacuum pump establishes air flow into one of the intakes and a sampling process controller, coupled between each intake and filter pairing and to the vacuum pump, controls the vacuum pump's establishing of air flow into a selected particulate intake. Preferably, the vacuum pump and sampling process controller reside within a hub unit to which multiple satellite units can be coupled such that each satellite unit employs the vacuum pump and sampling process controller of the hub unit. Due to central processing, conditional sampling at one or more of the units is possible. Further details and manual particulate sampling methods are presented.

Abstract: In an inertial mass measurement instrument, an active force compensator compensates for inertial forces transmitted by an oscillating elastic element to a primary support of the instrument. The compensator applies equal and opposite compensating forces to the primary support along an effective line of action of the oscillating element. Application of the compensating forces result in a substantially zero net acceleration of the primary support and avoids measurement inaccuracies attributable to changes in properties of secondary support elements.