Bacterial Filters

Bacterial Filters

 

apparatus of various construction for cleansing fluids of bacteria and other microorganisms by means of filtration. The fluid passes through a porous surface as a result of a vacuum created on the other side of that surface or as a result of pressure exerted on the fluid being filtered. Several types of bacterial filters are used. Glass filters are round discs consisting of porous glass, sealed into funnels. Ceramic filters are made of kaolin or kieselguhr; the Chamberland and Berkefeld filters belong to this group. The former are shaped like hollow cylinders with a sealed base and are equipped with a glazed neck on top to which a rubber tube is attached to draw the fluid through the wall of the filter. Membranous filters, produced from acetylcellulose, nitrocellulose, and cellulose esters, are also used.

The pore size is varied in different bacterial filters, but in a sterilizing filter they must be no larger than 750 nanometers. In addition to pore dimension and the created vacuum (or pressure), several other factors—for example, electrical charge, viscosity and reaction of the fluid being filtered, and adsorption phenomena—also influence the speed of filtration. Bacterial filters are used for sterilization of fluids that may not be heated (solutions of certain medications, sera, nutrient media for microorganisms, and such). The number of microorganisms contained in rivers and other bodies of water may be determined by means of membranous bacterial filters. Cells trapped in the filter are stained and counted under the microscope.

A. A. IMSHENETSKII

References in periodicals archive ?
Aggregate supply and replacement of bacterial filters at water use points for the hospitals of the institut catal de la salut.
The suction electric machine also consists of bacterial filters which are replaceable and are replaced in every two months.
--While a reduction of particles within an incubator atmosphere can minimize the contamination risk in open culture systems, such as when working with Petri dishes, it should be noted that high-quality cell culture containers with integrated bacterial filters in the screw cap are available in order to block the entry of germs from the incubator atmosphere and to prevent securely any cross contamination between the individual cell culture containers.
Other microbial control devices include general in line bacterial filters. Millipore Corp.
bacterial filters for mechanical ventilation, 500 pcs.
bacterial filters for completing vacuum devices 100 pcs.
respiratory system with bacterial filters for transport ventilation stephan 150 pcs.
Request for quotations : bacterial filters for the department of anesthesiology and resuscitation for the 3rd quarter of 2018
32/18-EA "Adapters hinged, bacterial filters, air ducts and humidifiers"
Package 8 - bacterial filters for the administration of parenteral nutrition for newborns
Tenders are invited for for Supply of surgical consumables and insecticides for the year 2015-16 : 5mm Inserts For Lap Instruments Grasper Toothed ,96 Hours Online IV Bacterial Filters,Arterial Cannula 20G,Barburs Thread Size No 20,Collagen Sheets (Size 10cmx10cm),Collagen Sheets (Size 15cmx30cm) etc
Hand-held medication nebulizers offer optimal aerosol delivery, and the Aerogard II[R] hand held nebulizer includes a viral bacterial filter for environmentally safe medication delivery.