Particulate filter and method of use

Abstract

A particulate filter particularly suited for analytical gravimetric weighing applications is disclosed. The particulate filter includes a polytetrafluoroethylene (PTFE) media supported by a ring and yields stable microgram and submicrogram weighing results. The support ring may be PTFE, metal foil, or another non-hygroscopic polymer such that the mass of the filter does not vary with changes in atmospheric moisture. The filter simplifies the discharge of electrostatic charge buildup such that when a conductive filter media is combined with a conductive ring device, the discharge may be accomplished by placing the filter on a grounded weighing pan or other surface. The particulate filter can simplify filter identification by including identification symbols imprinted on each side of the filter media. Due to the chemically inert qualities of its components, the particulate filter is particularly suited for extraction techniques used during the detection of polycyclic hydrocarbons as is conducted in emissions and ambient air testing.

Description

RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 545,296, filed Feb. 16, 2004, and U.S. Provisional Application No. 60 / 549,076, filed Mar. 1, 2004, which are incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] Particulate filters have long been known and widely used. Particulate filters of various types have been utilized for decades in different applications, for example air filtration and analytical measurements in laboratories for a wide range of testing protocols. [0003] Of recent importance is a method of gravimetric analysis. Gravimetric analysis is founded on the principle that a weight of a substance is the elementary measurement used for calculation. In the case of gravimetric analysis of particulate filter applications, the results of a weighing before (pre weighing) and after (post weighing) exposure to an air stream are compared to calculate the load of particulate within the volume of air to which the...

AI Technical Summary

Benefits of technology

[0011] The particulate filter and methods of the invention thereby provide various advantages, such as one or more of improved efficiency and permeability, improved moisture stability, improved relative humidity stability, improved static stability, a ringed or ring-less design for improved handling, and the optional functionality of being printable with an identification symbol or code to facilitate automated filter handling and weighing in some embodiments. Embodiments of the particulate filter device of the invention simplify the discharge of electrostatic charge buildup, provide improved identification methods and means, and may be used to accurately measure particulate pollutants and materials.

Problems solved by technology

To date no known particulate filter has been designed to address specifically improved performance, stability, and usability at the microgram and sub microgram level and for various applications.

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