# US 11,077,957 B2 · Selectable barrier filtration system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,957 B2 - Document ID: US11077957B2 - Status: Granted - Kind: B2 - Application number: 15/878,075 - Filed: 2018-01-23 - Published: 2018-07-26 - Granted: 2021-08-03 - Earliest claimed: 2017-01-23 - Assignees: Textron Innovations Inc. - Applicants: Bell Helicopter Textron Inc. - Inventors: Thomas Dewey Parsons; David Haynes; David L. Miller; Bradley Robert Henson - Web page: https://patentgrep.com/patent/US11077957B2 ## CPC - B64D 33/02: of combustion air intakes - F02C 7/055: with intake grids, screens or guards - B64D 2033/0246: {comprising particle separators} - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2220/90: in vehicles adapted for vertical or short take off and landing (v/stol vehicles) - F05D 2260/606: Bypassing the fluid - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN 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 ## Abstract An air intake system (AIS) has a plenum and an inlet barrier filter associated with the plenum, through which air can selectively enter the plenum. The AIS also has an inlet duct associated with the plenum, through which air can selectively enter the plenum. The AIS also has a bypass door associated with the inlet duct, the bypass door being configured to selectively change an amount of air allowed to pass through the inlet duct. The AIS also has a filter airflow change device configured to change an amount of airflow allowed through the inlet barrier filter. ## Claims ### Claim 1 An air intake system (AIS), comprising: a plenum; an inlet barrier filter associated with the plenum, through which air can selectively enter the plenum; an inlet duct associated with the plenum, through which air can selectively enter the plenum; a bypass door associated with the inlet duct, the bypass door being configured to selectively change an amount of air allowed to pass through the inlet duct; and a filter airflow change device configured to change an amount of airflow allowed through the inlet barrier filter; wherein the filter airflow change device comprises a tubular slide valve and a carrier duct and wherein the slide valve is configured to receive at least a portion of a tubular portion of the carrier duct; wherein when the tubular slide valve is fully extended relative to the carrier duct, airflow from the inlet duct to an engine intake duct via the inlet barrier filter is substantially reduced and airflow to the engine intake duct via the inlet duct is substantially increased; and wherein movement of the tubular slide valve relative to the carrier duct changes an amount of longitudinal overlap between the tubular slide valve and the carrier duct. ### Claim 2 (depends on 1) The AIS of claim 1, wherein the filter airflow change device is movable relative to the inlet barrier filter. ### Claim 3 (depends on 2) The AIS of claim 2, wherein the filter airflow change device is a filter door. ### Claim 4 (depends on 3) The AIS of claim 3, wherein the filter door is configured to slide relative to the inlet barrier filter. ### Claim 5 (depends on 1) The AIS of claim 1, wherein the tubular slide valve is movable along a curved path to selectively provide a closed airflow path from the inlet duct to the engine intake duct. ### Claim 6 An aircraft, comprising: an engine comprising an engine compressor intake; a plenum; an inlet barrier filter associated with the plenum, through which air can selectively enter the plenum; an inlet duct associated with the plenum, through which air can selectively enter the plenum; a bypass door associated with the inlet duct, the bypass door being configured to selectively change an amount of air allowed to pass through the inlet duct and to the engine compressor intake; and a filter airflow change device configured to change an amount of airflow allowed through the inlet barrier filter and to the engine compressor intake; wherein the filter airflow change device comprises a tubular slide valve and a carrier duct and wherein the slide valve is configured to receive at least a portion of a tubular portion of the carrier duct; wherein when the tubular slide valve is fully extended relative to the carrier duct, airflow from the inlet duct to an engine intake duct via the inlet barrier filter is substantially reduced and airflow to the engine intake duct via the inlet duct is substantially increased; and wherein movement of the tubular slide valve relative to the carrier duct changes an amount of longitudinal overlap between the tubular slide valve and the carrier duct. ### Claim 7 (depends on 6) The aircraft of claim 6, wherein the filter airflow change device is movable relative to the inlet barrier filter. ### Claim 8 (depends on 7) The aircraft of claim 7, wherein the filter airflow change device is a filter door. ### Claim 9 (depends on 8) The aircraft of claim 8, wherein the filter door is configured to slide relative to the inlet barrier filter. ### Claim 10 (depends on 6) The aircraft of claim 6, wherein the tubular slide valve is movable along a curved path to selectively provide a closed airflow path from the inlet duct to an engine intake duct. ### Claim 11 A method of operating an aircraft, comprising: selectively providing a first airflow path between an inlet duct and an engine compressor intake; selectively providing a second airflow path between an inlet barrier filter and the engine compressor intake; and operating a filter airflow change device configured to change an amount of airflow allowed through the inlet barrier filter; wherein the filter airflow change device comprises a tubular slide valve and a carrier duct and wherein operating the slide valve comprises changing an amount of a tubular portion of the carrier duct received within the slide valve; fully extending the tubular slide valve relative to the carrier duct so that airflow from the inlet duct to an engine intake duct via the inlet barrier filter is substantially reduced and airflow to the engine intake duct via the inlet duct is substantially increased; and wherein movement of the tubular slide valve relative to the carrier duct changes an amount of longitudinal overlap between the tubular slide valve and the carrier duct. ### Claim 12 (depends on 11) The method of claim 11, further comprising: reducing airflow through the first airflow path and increasing airflow through the second airflow path. ### Claim 13 (depends on 11) The method of claim 11, further comprising: increasing airflow through the first airflow path and reducing airflow through the second airflow path. ### Claim 14 (depends on 11) The method of claim 11, further comprising: moving the tubular slide valve along a curved path.