Abstract: A high air volume to low liquid volume aerosol collector. A high volume flow of aerosol particles is drawn into an annular, centripetal slot in a collector which directs the aerosol flow into a small volume of liquid pool contained is a lower center section of the collector. The annular jet of air impinges into the liquid, imbedding initially airborne particles in the liquid. The liquid in the pool continuously circulates in the lower section of the collector by moving to the center line, then upwardly, and through assistance by a rotating deflector plate passes back into the liquid at the outer area adjacent the impinging air jet which passes upwardly through the liquid pool and through a hollow center of the collector, and is discharged via a side outlet opening. Any liquid droplets escaping with the effluent air are captured by a rotating mist eliminator and moved back toward the liquid pool.

Abstract: A method and apparatus are provided for measuring the aerodynamic particle size distribution of airborne particles by drawing the particles through a device 10a which continuously or intermittently changes the aerodynamic cut of the particles entering an aerosol sensor. Sensing is performed by optical sensors 16 such as aerosol photometry or optical single particle size spectrometry or by other sensors that measure particle concentration remaining in the aerosol flowing from the cut device. Preferably, the cut device includes a rotational element 22 that centrifugally removes particles of larger aerodynamic size than that determined by a cut setting, which can be varied by varying the rotational speed of the cut element. Preferably also, the rotary element does not alone determine the flow rate of the aerosol through the cut device, but a separate pump 40 or flow restriction controls the time the aerosol remains in the cut device and maintains the flow rate through the device at a preferably constant level.

Abstract: A method for concentrating airborne particles and microorganisms by injecting them into a swirling air flow from where they are removed into one or more receiving tubes. The swirling air motion and the aerosol injection into it are achieved by pushing or drawing the airborne particles and microorganisms through one or more nozzles that are directed at an angle towards the surface of the containment vessel. The ratio of air flow rate into the vessel to the air flow rate through the receiving tube is equal to the maximum aerosol concentrating ratio desired.

Abstract: A method for the collection of solid or liquid particles suspended in air (aerosol). The method involves abstracting a quantity of air through a curved, porous plate with evenly spaced holes which are designed to give an accurate sample of the particle content over defined size ranges. This method differs from similar methods in that it (1) provides a minimal bias in the results from the effects of ambient air velocity or direction, (2) provides a more even distribution of particles over a collection medium, and (3) enables exclusion of particles exceeding defined upper size limits.

Abstract: An aerosol sampler for use with a source of vacuum. Air is drawn through a perforated hemisphere, directing small particles and aerosols for collection on a filter surface downstream of the hemisphere. A high collection efficiency is demonstrated.

Abstract: A method is provided for measuring the aerodynamic particle size distribution of airborne particles by drawing the particles through a device which continuously or intermittently changes the aerodynamic cut of the particles entering an optical sensor. Optical sensing is performed by aerosol photometry or optical single particle size spectrometry. If aerosol photometry is used, the aerosol photometer becomes an aerodynamic particle size spectrometer by relating the aerosol photometer's output to the aerodynamic particle size fractions passing through the aerodynamic cut device. If optical single particle size spectrometry is used, the optical single particle counter becomes an aerosol particle size spectrometer by calibrating the optical sizes of the optical single particle counter relative to the aerodynamic particle sizes determined by the aerodynamic cut device.

Abstract: A method for collecting airborne particles and microorganisms by injecting them into a swirling air flow from where they are removed onto a dry surface, a surface coated with an adhesive material or a surface wetted by a liquid that is swirled onto that surface from a liquid reservoir below. The swirling air motion and the aerosol injection into it are achieved by pushing or drawing the airborne particles and microorganisms through one or more nozzles that are directed at an angle towards the collection surface.

Abstract: An apparatus for collecting airborne particles and microorganisms by injecting them into a swirling air flow from where they are removed onto a dry surface, a surface coated with an adhesive material or a surface wetted by a liquid that is swirled onto that surface from a liquid reservoir below. The swirling air motion and the aerosol injection into it are achieved by pushing or drawing the airborne particles and microorganisms through one or more nozzles that are directed at an angle towards the collection surface. Each entire nozzle or only its exit section are aligned along the axis of aerosol flow injection into the swirling air flow. The apparatus consists of one piece or of three main components that are assembled to form one unit and are comprised of one inlet section, one nozzle section, and one collection vessel.

Abstract: A method and apparatus for conducting the method is disclosed for non-invasive, quantitative respirator fit testing. The method includes the step of having the wearer properly position the respirator over his nose and mouth, inhale to create a negative pressure inside the respirator cavity volume, hold his breath and record the pressure differential versus time decay rate between the pressure inside the respirator cavity volume and that of the surrounding environment. The method may also include establishing a leakhole of known dimension, repeating the above steps and determining the volume of the respirator cavity based upon the results of the recorded differential pressure versus time by comparing the result to calibration curves.The apparatus of the present invention includes modifying a conventional face mask respirator by providing the respirator with a pressure sensor and a leakhole of known dimension.

Abstract: A highly efficient solar heat collector characterized by a layer of light transmitting insulating (i.e., convection and infra-red radiation suppressing) material disposed between the outer surface of the collector and the heat absorptive layer thereof. Glass fibers are a particularly effective lightweight insulating material which may be used. Through use of flexible polymeric films, lightweight, low-cost solar heat collectors may be fabricated for conversion of existing structures to partial or complete solar heating. Either gaseous or liquid heat transfer fluids may be used. A novel gas-liquid heat exchange system is disclosed.