# US 11,028,850 B2 · Chopper pump with double-edged cutting bars > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,028,850 B2 - Document ID: US11028850B2 - Status: Granted - Kind: B2 - Application number: 16/525,808 - Filed: 2019-07-30 - Published: 2019-11-21 - Granted: 2021-06-08 - Earliest claimed: 2017-03-13 - Assignees: Vaughan Co., Inc. - Applicants: Vaughan Company, Inc. - Inventors: Kent Keeran; Arne Swenson - Web page: https://patentgrep.com/patent/US11028850B2 ## CPC - F04D 7/045: {with means for comminuting, mixing stirring or otherwise treating} - B02C 18/0092: {for waste water or for garbage} - F04D 29/2288: {for comminuting, mixing or separating} - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - B02C: CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN ({household tools and machines for pulverising foodstuffs, e.g. coffee and spice mills A47J42/00; pharmaceutical mortars A61J3/02; mechanical processing of refuse and garbage B03B9/06; dressing mould materials by grinding B22C5/04}; obtaining metallic powder by crushing, grinding or milling B22F9/04; {recovery of plastics by disintegrating B29B17/00; crushing raw materials in starch making C08B30/02; beaters for papermaking D21D1/02; crushing devices specially for transport in mines E21F13/002; slag crushing devices F23J1/00; fuel milling devices in combustion apparatus F23K1/00; household devices for crushing coal F24B15/02; ice disintegrating devices F25C5/02}) ## Abstract An impeller assembly with an impeller and a cutter bar plate is used in a chopper pump system which handles liquid material sometimes entrained with large debris and stringy matter. The debris and matter present clogging hazards, which are reduced by a combination of scissoring between sharpened impeller blades and shearing fingers, and between cutting wings and shearing fingers. To make the cutting feature more aggressive, sharpened edges along two of the scissoring edges of the shearing fingers are utilized. Preferably, the sharpened edges are either the result of machined v-notches on the cutting surface of the shearing fingers or of a casted part having a cupped surface. Generally speaking, the impeller assembly comprises an impeller attached to a rotatable pump shaft and includes a back shroud. ## Claims ### Claim 1 An impeller assembly for a chopper pump comprising: an impeller having a back shroud and cutting blades sharpened on a first edge, the cutting blades extending from and fixed on a first surface of the back shroud; a cutter bar plate positioned adjacent to and upstream of the impeller, the cutter bar plate comprising at least one shearing finger having first and second contact surfaces and extending inward from a periphery, the first contact surface of the at least one shearing finger having a first sharpened edge and the second contact surface having a second sharpened edge, such that the first sharpened edge creates a shearing operation in combination with the sharpened edge of the cutting blades of the impeller during use; and an external tool positioned adjacent to and upstream of the cutter bar plate, the external tool comprising at least one cutting wing having a shearing surface that creates a shearing operation in combination with the second sharpened edge along the second contact surface of the shearing finger during use; wherein the shearing finger has a cupped surface parallel to a longitudinal axis of the shearing finger and between the first and second contact surfaces to create the first and second sharpened edges. ### Claim 2 (depends on 1) The assembly of claim 1, wherein the first sharpened edge has a length which is equal to a length of the at least one shearing finger. ### Claim 3 (depends on 2) The assembly of claim 2, wherein the second sharpened edge has a length which is equal to a length of the at least one cutting wing. ### Claim 4 (depends on 2) The assembly of claim 2, wherein the second sharpened edge has a length which is less than the length of the first sharpened edge. ### Claim 5 (depends on 4) The assembly of claim 4, wherein the first and second sharpened edges are each on a first contacting face of the at least one shearing finger. ### Claim 6 (depends on 1) The assembly of claim 1, wherein a shearing gap in an axial direction between the at least one shearing finger and the cutting wing is in the range of from 0.010 to 0.030 inches. ### Claim 7 (depends on 1) The assembly of claim 1, wherein a shearing gap in an axial direction between the at least one shearing finger and the sharpened edge of the cutting blades is in the range of from 0.010 to 0.030 inches. ### Claim 8 (depends on 6) The assembly of claim 6, wherein the gap is in the range of from 0.015 to 0.025 inches. ### Claim 9 (depends on 7) The assembly of claim 7, wherein the gap is in the range of from 0.015 to 0.025 inches. ### Claim 10 (depends on 1) The assembly of claim 1, wherein the cutter bar plate comprises two shearing fingers. ### Claim 11 A cutter bar plate for a chopper pump, the cutter bar plate comprising: a body configured to be positioned upstream from an impeller of a chopper pump, wherein the body comprises first and second opposing surfaces, the first surface being configured to face downstream and the second surface being configured to face upstream, and an opening defined through the body which allows material to flow past the first and second opposing surfaces; and at least one shearing finger fixed to the body and extending into the opening parallel to the first and second surfaces, wherein the at least one shearing finger comprises a front face normal to the first and second surfaces of the body, the front face having first and second contact surfaces; wherein the shearing finger comprises a cupped surface parallel to a longitudinal axis of the shearing finger and between the first and second contact surfaces to create a first sharpened edge disposed on the first contact surface and a second sharpened edge disposed on the second contact surface. ### Claim 12 (depends on 11) The cutter bar plate of claim 11, wherein the first sharpened edge has a length which is equal to a length of the at least one shearing finger in a radial direction. ### Claim 13 (depends on 12) The cutter bar plate of claim 12, wherein the second sharpened edge has a length in a radial direction which is less than the length of the first sharpened edge in the same radial direction. ### Claim 14 (depends on 11) The cutter bar plate of claim 11, wherein the at least one shearing finger comprises a curved-hook end. ### Claim 15 (depends on 11) The cutter bar plate of claim 11, comprising two shearing fingers. ### Claim 16 (depends on 11) The cutter bar plate of claim 11, wherein the body comprises an outer ring having an inner surface defining the opening, and the at least one shearing finger extends from the inner surface. ### Claim 17 (depends on 15) The cutter bar plate of claim 15, comprising two shearing fingers extending from the inner surface. ### Claim 18 (depends on 16) The cutter bar plate of claim 16, wherein each of the two shearing fingers comprises a curved-hook end.