# US 2023/0054596 A1 · Fast Acting Shuttle Spool Valve > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0054596 A1 - Document ID: US20230054596A1 - Status: Published application - Kind: A1 - Application number: 17/405,681 - Filed: 2021-08-18 - Published: 2023-02-23 - Earliest claimed: 2021-08-18 - Assignees: Southwest Research Institute - Applicants: Southwest Research Institute - Inventors: Riccardo Meldolesi; Anthony Perkins; Clive Lacy; Dustin Kramer - Web page: https://patentgrep.com/patent/US20230054596A1 ## CPC - F16K 3/26: with fluid passages in the valve member - F16K 11/07: with cylindrical slides - F01L 1/185: {Overhead end-pivot rocking arms} - F01L 1/2411: {by means of a hydraulic adjusting device located between the valve stem and rocker arm} - F15B 15/223: {having a piston with a piston extension or piston recess which completely seals the main fluid outlet as the piston approaches its end position} - F15B 21/14: Energy-recuperation means - F16K 3/24: with cylindrical valve members - F15B 2211/7052: Single-acting output members - F15B 2211/755: Control of acceleration or deceleration of the output member - 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)} - F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract A spool valve for controlling the flow of a fluid into a reciprocating piston cylinder. A spool is slideably inserted into an outer casing, the spool valve having a first and a second non-waisted end portions and having a waisted middle portion. The casing has an intake port and output port for fluids entering and exiting the casing. A first non-waisted end portion covers the intake port during a first valve-closed event as the spool slides in one direction within the casing. The waisted middle portion is sufficiently wide to uncover both the intake port and the output port during a valve-open event as the spool slides in one direction within the casing. A second non-waisted end portion covers the output port during a second valve-closed event as the spool slides in the same one direction within the casing. ## Claims ### Claim 1 A spool valve for controlling the flow of a fluid into a reciprocating piston cylinder, comprising: an outer casing; a spool slideably inserted into the casing, the spool valve having a first and a second non-waisted end portions and having a waisted middle portion; an intake port for fluids entering the casing; an output port for fluids exiting the casing; wherein a first non-waisted end portion covers the intake port during a first valve-closed event as the spool slides in one direction within the casing; wherein the waisted middle portion is sufficiently wide to uncover both the intake port and the output port during a valve-open event as the spool slides in the one direction within the casing; and wherein a second non-waisted end portion covers the output port during a second valve-closed event as the spool slides in the one direction within the casing. ### Claim 2 (depends on 1) The spool valve of claim 1, further comprising an actuator operable to both push and pull the spool within the casing, such that a valve-open event and the first and the second valve-closed events occur as the actuator pushes and pulls the spool. ### Claim 3 (depends on 2) The spool valve of claim 2, wherein the actuator is a cam actuator that pushes the spool against a coil spring. ### Claim 4 (depends on 2) The spool valve of claim 2, wherein the actuator is a cam actuator that pushes the spool against a gas spring. ### Claim 5 (depends on 2) The spool valve of claim 2, wherein the actuator is a crank actuator. ### Claim 6 A spool valve for controlling the flow of a gas into a reciprocating piston cylinder, comprising: an outer casing; a spool slideably inserted into the casing, the spool valve having a first and a second non-waisted end portions and having a waisted middle portion; an intake port for fluids entering the casing; an output port for fluids exiting the casing; wherein a first non-waisted end portion covers the intake port during a first valve-closed event as the spool slides in one direction within the casing; wherein the waisted middle portion is sufficiently wide to uncover both the intake port and the output port during a valve-open event as the spool slides in the one direction within the casing; wherein a second non-waisted end portion covers the output port during s second valve-closed event as the spool slides in the one direction within the casing; a gas actuator operable to both push and pull the spool within the casing, such that a valve-open event and the first and the second valve-closed events occur as the actuator pushes and pulls the spool; wherein the gas actuator comprises a chamber within the casing at both ends of the spool and a poppet valve associated with each chamber operable to compress and expand sCO2 gas within the chamber. ### Claim 7 (depends on 6) The spool valve of claim 6, wherein the gas is an SCO2 gas. ### Claim 8 (depends on 6) The spool valve of claim 6, wherein the reciprocating piston cylinder is part of a gas expander. ### Claim 9 A method of operating a spool valve to control the flow of a fluid into a reciprocating piston cylinder, comprising: slideably inserting a spool into a casing, the spool valve having a first and a second non-waisted end portions and having a waisted middle portion; providing an intake port for fluids entering the casing; providing an output port for fluids exiting the casing; wherein a first non-waisted end portion covers the intake port during a first valve-closed event as the spool slides in one direction within the casing; wherein the waisted middle portion is sufficiently wide to uncover both the intake port and the output port during a valve-open event as the spool slides in the one direction within the casing; wherein a second non-waisted end portion covers the output port during s second valve-closed event as the spool slides in the one direction within the casing; actuating the spool valve such that such that a valve-open event and the first and the second valve-closed events occur during a first cycle of the piston as the spool moves in a first direction and such that a second valve-open event and a third and a fourth valve-closed events occur occurs during a second cycle of the piston; and repeating the actuating step for subsequent cycles of the piston. ### Claim 10 (depends on 9) The method of claim 9, further comprising using an actuator operable to both push and pull the spool within the casing, such that a valve-open event and the first and the second valve-closed events occur as the actuator pushes and pulls the spool. ### Claim 11 (depends on 10) The method of claim 10, wherein the actuator is a cam actuator that pushes the spool against a coil spring. ### Claim 12 (depends on 10) The method of claim 10, wherein the actuator is a cam actuator that pushes the spool against a gas spring. ### Claim 13 (depends on 10) The method of claim 10, wherein the actuator is a crank actuator. ### Claim 14 (depends on 10) The method of claim 10, wherein the actuator is a gas-driven actuator. ### Claim 15 (depends on 9) The method of claim 9, wherein the fluid is a gas, and further comprising using a portion of the same gas in an actuation flow to actuate the spool. ### Claim 16 (depends on 9) The method of claim 9, wherein the spool valve controls the flow of sCO2 (supercritical carbon dioxide) into a piston expander, and further comprising using a portion of the sCO2 in an actuation flow to actuate the spool.