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Collison Nebulizers |
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Applications
Features
The Collison Nebulizer has long been the recognized technique for the efficient aerosolization of various liquids.1,2. Over the years various configurations have been developed to meet specific requirements. BGI manufactures all of the currently used types and has performed extensive tests to determine the performance characteristics. It has previously been demonstrated that the 3-jet version2 will produce the same mass median diameter with one-half the air flow and liquid generation rate of the 6-jet version. Similarly, the short form has been shown to produce the same mass median diameter as the standard height unit2. The modified MRE-type is a flat bottomed version of the design used by the Microbiological Research Establishment at Porton, U.K. It is available in either 3 or 6-jet configuration. All metal components are fabricated from 316 stainless steel. This design has been the subject of developmental testing and was the principle source of the data presented below. It should be noted that the "T" formation at the top of the unit provides for the air inlet and the attachment of a pressure gauge. This BGI innovation eliminates the frequently encountered error involved when the pressure is measured at some remote source. The modified MRE-type short form was specifically developed to meet the needs of the National Sanitation Foundation. Their requirement for testing Biological Hazard Enclosures involved limited space requirements resulting in the shorter configuration. This unit has been the subject of extensive testing with spores. The unit is fitted with the 6-jet nozzle and is fabricated from electroless nickel plated brass. Due to increased awareness on the subject of sinister biological substances, there has been an increase in the number of investigators who are handling hazardous materials to be aerosolized. In order to provide the utmost freedom from accidental exposure, a 316 stainless steel jar has been designed and manufactured to meet this need. It is compatible with all models of the MRE 1, 3 and 6 jet models. The CN40 Glass precious fluids bottle is intended for use with materials which are expensive or difficult to obtain. It must be utilized with the extension sleeve. The sleeve pushes over the end of the collison nozzle and dips into the well. This sleeve permits the nozzle to remain in a higher position so that the nozzles output may properly impinge upon the jar. The volume of the well is 5 ml. The bottle may be used with 3 or 6-jet units. The external fill adaptor is designed to permit the instrument to be intermittently or continuously replenished without interrupting a procedure. Beginning in early 1995 all collison nozzles contain a fill hole which permits insertion of the needle shown in the photograph. Liquids injected into the system emerge under at the bottom of the nozzle and do not interfere with the generation of aerosol. The external portion of the filler is provided with a cap. 24 Jet Collison. Over the past two decades, BGI has been frequently asked to manufacture Collison Nebulizers with more than 3 or 6 jets. This has previously been carried out on a custom basis. The now-standardized 24 Jet Collison is a carefully scaled up version of the 6 Jet, MRE type collison. A 32 oz., clear pre-coated jar is utilized to maintain the identical wall to plate spacing of the three and six jet nebulizer. Thus the new unit produces the same characteristic aerosol as the six jet with four times the output, except that the maximum pressure limit is 30 PSIG.
1. May K.R. (1973) The Collison Nebulizer. Description, Performance & Application J. of Aerosol Science, Vol. 4, #3, p. 235. 2. Gussman, R.A. (1984) Note on the Paricle Size Output of Collison Nebulizers, Am. Ind. Hyg. Assoc. J (45). Copyright © 2006 by BGI / Modified:
Tuesday, December 8, 2009
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