# US 10,309,312 B2 · Fuel metering device protected against icing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,312 B2 - Document ID: US10309312B2 - Status: Granted - Kind: B2 - Application number: 15/746,227 - Filed: 2016-07-19 - Published: 2018-07-26 - Granted: 2019-06-04 - Earliest claimed: 2015-07-21 - Assignees: Safran Aircraft Engines - Applicants: Safran Aircraft Engines - Inventors: Jean-Marie Brocard; Régis Michel Paul Deldalle; Anne Marie Cécile Barreau; Pierre Charles Mouton - Web page: https://patentgrep.com/patent/US10309312B2 ## CPC - F02C 7/232: Fuel valves {(control of fuel supply by means of fuel metering valves F02C9/263)}; Draining valves or systems (valves in general F16K) - F02C 7/222: {Fuel flow conduits, e.g. manifolds} - F02C 7/224: Heating fuel before feeding to the burner - F02C 7/236: Fuel delivery systems comprising two or more pumps - F02C 9/263: {by means of fuel metering valves} - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2240/35: Combustors or associated equipment - F05D 2250/90: Variable geometry - F05D 2260/607: Preventing clogging or obstruction of flow paths by dirt, dust, or foreign particles - F16K 3/26: with fluid passages in the valve member - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)} - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A fuel metering unit comprising a movable element including at least one fuel flow section opening upstream towards a fuel supply duct and opening downstream towards a utilization duct through a metering slot with a flared profile having a narrow flow section and a wide flow section, the movable element able to be moved with respect to a stationary element between a low flow rate position and a high flow rate position, the metering slot made in the stationary element or in the movable element and its obstruction obtained by covering the slot with a wall of the movable element or of the stationary element. ## Claims ### Claim 1 A fuel metering unit able to operate under icing conditions of the fuel, comprising a movable element including at least one fuel flow section opening upstream towards a fuel supply duct and opening downstream towards a utilization duct through a metering slot with a flared profile having a narrow flow section and a wide flow section, the movable element being able to be moved relatively to a stationary element only over a predetermined stroke between a low flow rate position in which the metering slot is for a large part obstructed and a high flow rate position in which the metering slot is for a great part exposed, the metering slot being made in the stationary element or in the movable element and its obstruction being obtained by covering the slot with a wall of the movable element or of the stationary element, the metering unit being characterized in that it further includes obstruction means for obstructing at least partly the narrow flow section of the metering slot when the metering unit is in the high flow rate position, without ever obstructing the wide flow section of said metering slot. ### Claim 2 (depends on 1) The metering unit according to claim 1, wherein the metering slot is made in the stationary element and opens into the fuel flow section via an opening made in the movable element and longitudinally delimited between a main edge and a secondary edge, said opening having a shorter length than a length of the metering slot and being able to move facing the latter so as to at least partly obstruct the narrow flow section of the metering slot when the metering unit is in the high flow rate position. ### Claim 3 (depends on 2) The metering unit according to claim 2, wherein the stationary element forms a bushing which comprises a window opening upstream towards the fuel supply duct and opening into the fuel flow section, said window being longitudinally shifted with respect to the metering slot. ### Claim 4 (depends on 3) The metering unit according to claim 3, wherein the movable element forms a slider able to longitudinally slide in the bushing, and the secondary edge is formed by a shoulder protruding into the fuel flow section between two end faces of the slider. ### Claim 5 (depends on 4) The metering unit according to claim 4, wherein the shoulder is an element added on the slider. ### Claim 6 (depends on 2) The metering unit according to claim 2, wherein the stationary element comprises a window opening upstream towards the fuel supply duct and opening into the fuel flow section, said window being alternatively longitudinally aligned with the metering slot with reference to a longitudinal axis of the flow structure. ### Claim 7 (depends on 2) The metering unit according to claim 2, wherein the stationary element further comprises an orifice opening into the fuel flow section and opening towards a utilization duct, said orifice being obstructed by the secondary edge of the opening of the movable element when the latter is in the high flow rate position and exposed when it is in the low flow rate position. ### Claim 8 (depends on 7) The metering unit according to claim 7, wherein the secondary edge of the movable element has a profiled profile so as to allow obstruction of the orifice as soon as the narrow flow section of the metering slot begins to be obstructed. ### Claim 9 (depends on 2) The metering unit according to claim 2, wherein the stationary element further comprises an orifice opening towards a utilization duct, and the movable element comprises an additional opening through which the fuel flow section opens towards the utilization duct, said additional opening being able to be moved facing said orifice so as to be able to obstruct it when the metering unit is in the high flow rate position. ### Claim 10 (depends on 1) The metering unit according to claim 1, wherein the metering slot is made in the movable element facing the fuel flow section and opens towards the utilization duct via an opening made in the stationary element and longitudinally delimited between a main edge and a secondary edge, said opening having a shorter length than a length of the metering slot and the metering slot being able to be moved facing the opening so that at least one portion of the narrow flow section of the metering slot is obstructed when the metering unit is in the high flow rate position. ### Claim 11 (depends on 10) The metering unit according to claim 10, wherein the stationary element comprises a window opening upstream towards the fuel supply duct and opening into the fuel flow section, said window being longitudinally shifted with respect to the opening. ### Claim 12 (depends on 1) The metering unit according to claim 1, wherein the movable element includes at least two end faces and said at least one fuel flow section is located between said end faces. ### Claim 13 (depends on 1) The metering unit according to claim 1, wherein the narrow flow section of the metering slot flares to the wide flow section. ### Claim 14 (depends on 1) The metering unit according to claim 1, wherein the narrow flow section of the metering slot possesses a width having a maximum lying in the range 0.5 mm to 1 mm. ### Claim 15 (depends on 1) The metering unit according to claim 1, wherein the narrow flow section and the wide flow section of the metering slot form two disjoint portions leading respectively to a low flow rate utilisation duct and to a high flow rate utilisation duct. ### Claim 16 (depends on 15) The metering unit according to claim 15, wherein the movable element and the stationary element are respectively in the form of a piston and of a cylinder, the two disjoint portions of the metering slot being formed in the stationary element, the metering unit having a second metering slot in which the narrow flow section and the wide flow section likewise form two disjoint portions formed in the stationary element, the narrow flow section and the wide flow section of the first metering slot being diametrically opposite relative to the narrow flow section and the wide flow section respectively of the second metering slot. ### Claim 17 (depends on 1) A fuel supply circuit of an aircraft engine, including a low pressure pumping system connected to a high pressure pumping system, and a fuel metering unit according to claim 1 for which the fuel flow section opens in the downstream direction towards combustion chamber injectors of the engine.