# US 10,502,245 B2 · Actuator cooling flow limiter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,245 B2 - Document ID: US10502245B2 - Status: Granted - Kind: B2 - Application number: 15/689,635 - Filed: 2017-08-29 - Published: 2019-02-28 - Granted: 2019-12-10 - Earliest claimed: 2017-08-29 - Assignees: Hamilton Sundstrand Corporation - Applicants: Hamilton Sundstrand Corporation - Inventors: Charles E. Reuter; Richard H. Bostiga - Web page: https://patentgrep.com/patent/US10502245B2 ## CPC - F15B 21/042: Controlling the temperature of the fluid - F01D 17/26: fluid, e.g. hydraulic - F15B 11/08: with only one servomotor - F15B 13/042: operated by fluid pressure {(F15B13/0401, F15B13/0416 take precedence)} - F15B 15/1485: {Special measures for cooling or heating} - F05D 2260/20: Heat transfer, e.g. cooling - F05D 2260/606: Bypassing the fluid - F05D 2270/64: Hydraulic actuators - F15B 11/024: by means of differential connection of the servomotor lines, e.g. regenerative circuits - F15B 13/021: {Valves for interconnecting the fluid chambers of an actuator} - F15B 13/0401: {Valve members; Fluid interconnections therefor} - F15B 15/1428: {Cylinders (F15B15/1438 takes precedence)} - F15B 15/149: {Fluid interconnections, e.g. fluid connectors, passages} - F15B 2011/0246: {with variable regeneration flow} - F15B 2211/205: Systems with pumps - F15B 2211/3058: having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode - F15B 2211/62: Cooling or heating means - F15B 2211/7051: Linear output members - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A cooling flow circuit is provided and includes a main line having first and second sections ported to piston extend and return sides of the gas turbine engine actuator, respectively, an orifice disposed along the main line between the first and second sections, a bypass line and a bypass valve. The bypass line is fluidly coupled to the first and second sections at opposite ends thereof, respectively. The bypass valve is disposed along the bypass line between the opposite ends thereof. The bypass valve has a variable flow area which is responsive to a pressure differential between the first and second sections. ## Claims ### Claim 1 A cooling flow circuit, comprising: a main line having first and second sections ported to piston extend and return sides of a gas turbine engine actuator, respectively; an orifice disposed along the main line between the first and second sections; a bypass line fluidly coupled to the first and second sections at opposite ends thereof, respectively; and a bypass valve disposed along the bypass line between the opposite ends thereof and having a variable flow area which is responsive to a pressure differential between the first and second sections, wherein the bypass valve comprises a first valve opening which is fluidly coupled to one end of the bypass line, a second valve opening which is fluidly coupled to the other end of the bypass line, a valve element and springs by which the valve element is anchored to the first and second valve openings and by which the valve element is elastically biased to move between open and closed positions relative to the first and second valve openings in response to the pressure differential. ### Claim 2 (depends on 1) The cooling flow circuit according to claim 1, wherein the orifice is sized for a non-minimal pressure differential between the first and second sections. ### Claim 3 An actuation system, comprising: an actuator comprising a piston and a housing cooperatively defining first and second interiors on extend and retract sides of the piston, the housing further defining a main line by which the first and second interiors are fluidly communicative; a fluid source; a remote servo valve fluidly interposed between the actuator and the fluid source, fluid supplied from the fluid source being exclusively provided to the first and second interiors from the remote servo valve; and a flow circuit coupled to the main line and having a variable flow area through which fluid is permitted to flow between the first and second interiors, the variable flow area being variable in response to a pressure differential between the first and second interiors, wherein the flow circuit comprises first and second sections of the main line, an orifice disposed along the main line between the first and second sections, a bypass line fluidly coupled to the first and second sections at opposite ends thereof, respectively, and a bypass valve disposed along the bypass line between the opposite ends thereof and having a variable valve flow area which is responsive to a pressure differential between the first and second sections, and wherein the bypass valve comprises a first valve opening which is fluidly coupled to one end of the bypass line, a second valve opening which is fluidly coupled to the other end of the bypass line, a valve element and springs by which the valve element is anchored to the first and second valve openings and by which the valve element is elastically biased to move between open and closed positions relative to the first and second valve openings in response to the pressure differential. ### Claim 4 (depends on 3) The actuation system according to claim 3, wherein the fluid source comprises a pump. ### Claim 5 (depends on 4) The actuation system according to claim 4, further comprising: additional secondary piping by which the fluid supplied from the fluid source is moved from the pump to the remote servo valve; and additional tertiary piping by which the fluid supplied from the fluid source is returned to the pump from the remote servo valve. ### Claim 6 (depends on 3) The actuation system according to claim 3, wherein the remote servo valve is displaced from the housing. ### Claim 7 (depends on 3) The actuation system according to claim 3, wherein the orifice is sized for a non-minimal pressure differential between the first and second sections. ### Claim 8 A gas turbine engine actuation system, comprising: an actuator comprising a piston and a housing cooperatively defining first and second interiors on extend and retract sides of the piston, the piston being movable between extend and retract positions responsive to pressures within the first and second interiors, and the housing further defining a main line by which the first and second interiors are fluidly communicative; a pump; a remote servo valve physically displaced from the housing and fluidly interposed between the actuator and the pump, fluid supplied from the pump being exclusively provided to the first and second interiors from the remote servo valve; and a flow circuit coupled to the main line and having a variable flow area through which fluid is permitted to flow between the first and second interiors, the variable flow area being variable in response to a pressure differential between the first and second interiors, wherein the flow circuit comprises first and second sections of the main line, an orifice disposed along the main line between the first and second sections, a bypass line fluidly coupled to the first and second sections at opposite ends thereof, respectively, and a bypass valve disposed along the bypass line between the opposite ends thereof and having a variable valve flow area which is responsive to a pressure differential between the first and second sections, wherein the bypass valve comprises a first valve opening which is fluidly coupled to one end of the bypass line, a second valve opening which is fluidly coupled to the other end of the bypass line, a valve element and springs by which the valve element is anchored to the first and second valve openings and by which the valve element is elastically biased to move between open and closed positions relative to the first and second valve openings in response to the pressure differential. ### Claim 9 (depends on 8) The gas turbine engine actuation system according to claim 8, further comprising: additional secondary piping by which the fluid supplied from the pump is pumped to the remote servo valve; and additional tertiary piping by which the fluid supplied from the pump is returned thereto from the remote servo valve. ### Claim 10 (depends on 8) The gas turbine engine actuation system according to claim 8, wherein the orifice is sized for a non-minimal pressure differential between the first and second sections.