# US 10,119,897 B2 · Enhanced aerosol test for assessing filter integrity > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,119,897 B2 - Document ID: US10119897B2 - Status: Granted - Kind: B2 - Application number: 15/057,641 - Filed: 2016-03-01 - Published: 2016-10-13 - Granted: 2018-11-06 - Earliest claimed: 2015-04-08 - Assignees: EMD Millipore Corporation - Applicants: EMD Millipore Corporation - Inventors: Salvatore Giglia; David Nhiem; Gabriel Tkacik - Web page: https://patentgrep.com/patent/US10119897B2 ## CPC - G01N 15/088: {Investigating volume, surface area, size or distribution of pores; Porosimetry} - B01D 65/102: {Detection of leaks in membranes} - G01M 3/20: using special tracer materials, e.g. dye, fluorescent material, radioactive material - G01N 15/0826: {and measuring fluid flow rate, i.e. permeation rate or pressure change} - B01D 2273/18: Testing of filters, filter elements, sealings - G01N 2015/084: {Testing filters} - G01N 2015/0846: {by use of radiation, e.g. transmitted or reflected light} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR ## Abstract A method of aerosol integrity testing of filters, capable of detecting single defects that are less than 20 μm in diameter, and even as small as 2 μm in diameter, in liquid sterilizing grade filters such as filter cartridges. The method challenges the filter in a dry state with a particle stream of aerosol particles of the appropriate size and in the appropriate concentration, such that at least one or more of the particles in the stream will penetrate a defective region or regions within the membrane but will not penetrate in the integral region of the membrane. Wetting of the filter is not required. ## Claims ### Claim 1 A method of integrity testing a filter in the dry state, comprising: providing a liquid sterilizing grade filter to be tested in a dry state, wherein said liquid sterilizing grade filter is a filter capable of totally retaining a B. diminuta challenge level of 107 cfu/cm2 at a differential pressure of 30 psi; generating an aerosol particle stream at a pressure of at least 5 psig, wherein the particles in said stream have a suitable size and a suitable concentration to challenge said filter and penetrate any defective region in said filter but will not penetrate integral regions in said filter, wherein said concentration of said particles in said stream is at least 103 particles/cm3; and detecting particles that penetrate said defective region. ### Claim 2 (depends on 1) The method of claim 1, wherein defects in said filter that are as small as 2 microns are detected by said step of detecting particles that penetrate said defective region. ### Claim 3 (depends on 1) The method of claim 1, wherein said filter is pleated. ### Claim 4 (depends on 3) The method of claim 3, wherein said aerosol particle stream is generated with a plurality of atomizers at a pressure of 50 psig. ### Claim 5 (depends on 1) The method of claim 1, wherein said filter is housed in a cartridge. ### Claim 6 (depends on 1) The method of claim 1, wherein said aerosol particle stream comprises NaCl. ### Claim 7 (depends on 1) The method of claim 1, wherein said filter is a PVDF filter. ### Claim 8 (depends on 1) The method of claim 1, wherein said filter is a PES filter. ### Claim 9 (depends on 1) The method of claim 1, wherein said particles in said aerosol particle stream have a size and concentration to penetrate a defect less than 20 μm in diameter in said filter. ### Claim 10 (depends on 1) The method of claim 1, wherein the aerosol particle stream is generated at a pressure of 5-60 psig. ### Claim 11 (depends on 1) The method of claim 1, wherein said aerosol particle stream is generated by a plurality of atomizers. ### Claim 12 (depends on 1) The method of claim 1, wherein the particles in said stream have a concentration of 106 particles/cm3. ### Claim 13 (depends on 1) The method of claim 1, wherein the particles in said stream have a concentration in the range of 105-107 particles/cm3. ### Claim 14 (depends on 1) The method of claim 1, wherein said filter is a 0.2 μm rated filter. ### Claim 15 A method of integrity testing a filter in the dry state, comprising: providing a liquid sterilizing grade filter to be tested in a dry state, wherein said liquid sterilizing grade filter is a filter capable of totally retaining a B. diminuta challenge level of 107 cfu/cm2 at a differential pressure of 30 psi; generating an aerosol particle stream with at least one atomizer at a pressure of at least 5 psig, wherein the particles in said stream have a concentration of at least 103 particles/cm3 and have a size effective to penetrate a defect less than 20 μm in diameter if present in said filter but not effective to penetrate integral regions in said filter; challenging said filter with said aerosol particle stream; providing a particle detector downstream of said liquid sterilizing grade filter to detect any particles that penetrate said defect if present in said filter; and classifying said filter as non-integral if a particle is detected by said particle detector, and classifying said filter as integral if no particles are detected by said particle detector. ### Claim 16 (depends on 15) The method of claim 15, wherein the particles in said stream have a size effective to penetrate a defect less than 2 μm in diameter if present in said filter. ### Claim 17 (depends on 15) The method of claim 15, wherein said filter is pleated. ### Claim 18 (depends on 17) The method of claim 17, wherein said aerosol particle stream is generated with a plurality of atomizers at a pressure of 50 psig. ### Claim 19 (depends on 15) The method of claim 15, wherein said filter is housed in a cartridge. ### Claim 20 (depends on 15) The method of claim 15, wherein said aerosol particle stream comprises NaCl. ### Claim 21 (depends on 15) The method of claim 15, wherein said filter is a PVDF filter. ### Claim 22 (depends on 15) The method of claim 15, wherein said filter is a PES filter. ### Claim 23 (depends on 15) The method of claim 15, wherein the aerosol particle stream is generated at a pressure of 5-60 psig. ### Claim 24 (depends on 15) The method of claim 15, wherein said aerosol particle stream is generated by a plurality of atomizers. ### Claim 25 (depends on 15) The method of claim 15, wherein the particles in said stream have a concentration of 106 particles/cm3. ### Claim 26 (depends on 15) The method of claim 15, wherein the particles in said stream have a concentration in the range of 103-107 particles/cm3. ### Claim 27 (depends on 15) The method of claim 15, wherein said filter is a 0.2 μm rated filter.