# US 5,708,198 A · Ferrous particle counter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,708,198 A - Document ID: US5708198A - Status: Granted - Kind: A - Application number: 08/647,335 - Filed: 1996-05-09 - Granted: 1998-01-13 - Earliest claimed: 1994-03-17 - Assignees: Diagnetics, Inc. - Inventors: James C. Fitch; Stuart D. Bents - Web page: https://patentgrep.com/patent/US5708198A ## CPC - G01N 15/0656: {using electric, e.g. electrostatic methods or magnetic methods (by investigating individual particles G01N15/1031, G01N15/12)} - 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) ## Abstract A method of and apparatus for determining ferrous particle counts in a fluid within a machine fluid system. In a sequential process, a solid particle count in a fluid above at least one given particle size is determined to determine particle size distribution. Ferrous particles are separated from the fluid and a solid particle count in the fluid above at least one given particle size is again measured to determine the solid contamination level of non-ferrous particles only. The solid particle count is compared with the non-ferrous particle count to determine the ferrous particle count above at least one given particle size to determine particle size distribution in said machine fluid system caused by wear. ## Claims ### Claim 1 A method of determining ferrous particle contamination in a fluid within a machine fluid system caused by wear, which method comprises: a. determining particle size distribution by counting solid particle contamination in a portion of said fluid to determine a solid contamination particle count above at least one given particle size; b. separating ferrous particles from a portion of said fluid by passing through a ferrous mesh media magnetized by a magnetic field; c. determining particle size distribution by counting solid particle contamination in said portion of fluid after separating said ferrous particles to determine a non-ferrous solid contamination particle count above at least one given particle size; and d. determining particle size distribution by comparing said solid contamination distribution with said non-ferrous solid contamination distribution to determine a ferrous particle distribution above at least one given particle size in said machine fluid system caused by wear. ### Claim 2 (depends on 1) A method of determining ferrous particle contamination as set forth in claim 1 wherein a portion of fluid from said fluid system is allowed to pass through a separator chamber containing a ferrous mesh media which is magnetized by said magnetic field. ### Claim 3 (depends on 2) A method of determining ferrous particle contamination as set forth in claim 2 wherein said separator chamber is connected by a sampling probe to said fluid system so that fluid from said system will pass through said probe and through said chamber. ### Claim 4 (depends on 1) A method of determining ferrous particle contamination as set forth in claim 1 wherein said magnetic field is induced by a permanent magnet outside of said separator chamber. ### Claim 5 (depends on 1) A method of determining ferrous particle contamination as set forth in claim 1 wherein said magnetic field is induced by an electromagnet outside of said separator chamber. ### Claim 6 (depends on 1) A method of determining ferrous particle contamination as set forth in claim 1 wherein said solid particle and said non-ferrous solid contamination levels are measured by flow decay rates of said fluid. ### Claim 7 (depends on 1) A method of determining ferrous particle count as set forth in claim 1 wherein said first and said second solid contamination levels are compared through a central processing unit. ### Claim 8 A method of determining ferrous particle contamination in a fluid within a machine fluid system caused by wear, which method comprises: a. separating ferrous particles from a first portion of said fluid by passing through a ferrous mesh media magnetized by a magnetic field; b. determining particle size distribution by counting solid particle contamination in said first portion of fluid after removing said ferrous particles to determine a first solid contamination particle count above at least one given particle size; c. determining particle size distribution by counting solid particle contamination in a second portion of said fluid to determine a second solid contamination particle count above at least one given particle size; and d. determining particle size distribution by comparing said first solid contamination distribution with said second contamination distribution to determine a ferrous particle distribution above at least one given particle size in said machine fluid system caused by wear. ### Claim 9 An apparatus to determine ferrous particle contamination in a fluid within a machine fluid system caused by wear, which apparatus comprises: a. means to determine particle size distribution by measuring solid particle contamination in said fluid to determine a first solid contamination particle count above at least one given particle size; b. means to separate ferrous particles from said fluid by passing through a ferrous mesh media magnetized by a magnetic field; c. means to determine particle size distribution by measuring solid particle contamination in said fluid after separating said ferrous particles to determine a second solid contamination count above at least one given particle size; d. means to compare said first solid contamination count with said second contamination count to determine a ferrous particle count above said at least one given particle size; and e . means to determine a particle size distribution from said ferrous particle count in (d) above at least one given particle size. ### Claim 10 (depends on 9) An apparatus to determine ferrous particle count in a fluid as set forth in claim 9 wherein said means to separate ferrous particles includes a separator chamber having ferrous mesh media therein and wherein said magnetic field is induced by a magnet outside said separator chamber. ### Claim 11 (depends on 10) A apparatus to determine ferrous particle count in a fluid as set forth in claim 10 wherein said magnet may be moved in a radial arc to move the magnetic field into or out of the separator chamber. ### Claim 12 (depends on 10) An apparatus to determine ferrous particle count in a fluid as set forth in claim 10 wherein said separator chamber is formed from a non-ferrous material. ### Claim 13 (depends on 9) An apparatus to determine ferrous particle count in a fluid as set forth in claim 9 wherein said means to measure solid particle contamination to determine said first and second particle counts includes a filter for passing said fluid there through and a means to determine flow degradation of said fluid.