Abstract:
A particle charging method and apparatus are provided. An ion source is applied to a particle laden flow. The flow is introduced into a container in a laminar manner. The container has at least a first section, a second section and a third section. The first section includes wetted walls at a first temperature. A second section adjacent to the first section has wetted walls at a second temperature T2 greater than the first temperature T1. A third section adjacent to the second section has dry walls provided at a temperature T3 equal to or greater than T2. Additional water removal and temperature conditioning sections may be provided.
Abstract:
A method and apparatus to create water vapor supersaturation and particulate counts from an air sample. The method and apparatus include introducing an air sample into a chamber connected to an optical detector and an outlet by pumping at the outlet. The method further includes passing air through the chamber and optical detector in a steady flow, and subsequently closing the inlet while continuing the pumping to expand the air sample and exhaust a portion of the air sample through the optical detector. The walls of the particle chamber are wetted with a fluid such as water, and one portion of the wall is warmer than the other portions such that there is some condensational growth prior to the expansion, and yet more condensational growth during the expansion. The cycles are repeated by continuously repeating the introducing, passing and closing.
Abstract:
An apparatus and method for condensationally enlarging particles in a flow of air or other gas. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. The walls of the tube are wetted with a condensing fluid. The walls of the first portion of the coiled tube are held a temperature that is lower than the highest temperature in the second portion of the tube. The tube may have a third vapor recovery portion with wall temperature lower than the highest temperature in the second portion, and which optionally may not be coiled. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.
Abstract:
An apparatus and method for creating enlarged particles in a flow. The apparatus includes a coiled tube having a tube diameter and a coil diameter, the tube having an input receiving the flow and an output, the tube having a length between the input and the output. A heater heats a first portion of the tube along a first, longitudinal portion of the tube, and a cooler cools a second, longitudinal portion of the tube along at least a second portion of the tube. The method includes heating a first portion of the tube along a first longitudinal portion of the tube, and simultaneously cooling a second portion of the tube along at least a second longitudinal portion of the tube. While heating and cooling, the method includes introducing a flow into an interior of the tube at an input, the flow moving the output.
Abstract:
A parallel plate dimensional electrical mobility separator and laminar flow water condensation provide rapid, mobility-based particle sizing at concentrations typical of the remote atmosphere. Particles are separated spatially within the electrical mobility separator, enlarged through water condensation, and imaged onto a CCD array. The mobility separation distributes particles in accordance with their size. The condensation enlarges size-separated particles by water condensation while they are still within the gap of the mobility drift tube. Once enlarged the particles are illuminated by a laser. At a pre-selected frequency, typically 10 Hz, the position of all of the individual particles illuminated by the laser are captured by CCD camera. This instantly records the particle number concentration at each position. Because the position is directly related to the particle size (or mobility), the particle size spectra is derived from the images recorded by the CCD.
Abstract:
A particle charging method and apparatus are provided. An ion source is applied to a particle laden flow. The flow is introduced into a container in a laminar manner. The container has at least a first section, a second section and a third section. The first section includes wetted walls at a first temperature. A second section adjacent to the first section has wetted walls at a second temperature T2 greater than the first temperature T1. A third section adjacent to the second section has dry walls provided at a temperature T3 equal to or greater than T2. Additional water removal and temperature conditioning sections may be provided.
Abstract:
A method and apparatus to create water vapor supersaturation and particulate counts from an air sample. The method and apparatus include introducing an air sample into a chamber by passing a flow into the chamber through the inlet by pumping at the outlet. The method further includes closing the inlet while continuing the pumping to exhaust the air sample from the chamber through the outlet. The pumping is performed at a rate operable to reduce pressure inside the chamber such that the air sample in the central portion of the chamber cools, and water vapor from walls of the chamber has time to diffuse into the air sample in the chamber from the walls. The cycles are repeated by continuously repeating the introducing and closing. The walls of the chamber may be wet or dry.
Abstract:
A system includes a first and second condensation particle counter, each counter having an inlet port, a growth column, and an optical element for counting particles detected at the respective inlet ports. The counters are configured to include a wick in which the wick is wetted by water. A differential pressure sensor is coupled to the first inlet port and coupled to the second inlet port. The sensor is configured to provide a pressure signal. A processor is coupled to memory and configured to receive the first signal, the second signal, and the pressure signal and generate an output corresponding to a ratio of the first signal and the second signal and correlate the ratio with the pressure signal. A housing is configured to receive the first counter, the second counter, the differential pressure sensor, the processor, and the memory.
Abstract:
A method and apparatus to create water vapor supersaturation and particulate counts from an air sample. The method and apparatus include introducing an air sample into a chamber by passing a flow into the chamber through the inlet by pumping at the outlet. The method further includes closing the inlet while continuing the pumping to exhaust the air sample from the chamber through the outlet. The pumping is performed at a rate operable to reduce pressure inside the chamber such that the air sample in the central portion of the chamber cools, and water vapor from walls of the chamber has time to diffuse into the air sample in the chamber from the walls. The cycles are repeated by continuously repeating the introducing and closing. The walls of the chamber may be wet or dry.
Abstract:
A system includes a first and second condensation particle counter, each counter having an inlet port, a growth column, and an optical element for counting particles detected at the respective inlet ports. The counters are configured to include a wick in which the wick is wetted by water. A differential pressure sensor is coupled to the first inlet port and coupled to the second inlet port. The sensor is configured to provide a pressure signal. A processor is coupled to memory and configured to receive the first signal, the second signal, and the pressure signal and generate an output corresponding to a ratio of the first signal and the second signal and correlate the ratio with the pressure signal. A housing is configured to receive the first counter, the second counter, the differential pressure sensor, the processor, and the memory.