# US 2018/0223703 A1 · High efficiency steam engine having improved steam cutoff control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0223703 A1 - Document ID: US20180223703A1 - Status: Published application - Kind: A1 - Application number: 15/914,417 - Filed: 2018-03-07 - Published: 2018-08-09 - Earliest claimed: 2010-12-02 - Assignees: Thermal Power Recovery LLC - Applicants: Thermal Power Recovery LLC - Inventors: James V. Harmon, SR. - Web page: https://patentgrep.com/patent/US20180223703A1 ## CPC - F01L 9/20: by electric means - F01B 9/02: with crankshaft - F01B 17/04: Steam engines - F01B 31/26: Other component parts, details, or accessories, peculiar to steam engines - F01L 23/00: Valves controlled by impact by piston, e.g. in free-piston machines - F01B 2250/001: Valves for steam inlet or outlet - F01B 2250/002: Valves, brakes, control or safety devices for steam engines - F01L 9/40: Methods of operation thereof; Control of valve actuation, e.g. duration or lift - F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES - F01B: MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES (of rotary-piston or oscillating-piston type F01C; of non-positive-displacement type F01D; internal-combustion engines F02B; combustion-product engine plants F02G; machines or engines, other than of positive-displacement type, for liquids F03B; positive-displacement engines driven by liquids F03C; wind motors F03D; positive-displacement machines for liquids F04B; rotary-piston, or oscillating-piston, positive-displacement machines for liquids F04C) ## Abstract A high efficiency uniflow steam engine having automatic inlet and exhaust valves rather than camshaft operated valves includes an electromagnet and cooperating armature that actuates a cutoff control valve for closing a steam inlet valve at any time selected to cut off the flow of steam to the cylinder. Approaching the end of the exhaust stroke, e.g., about 0.12 inch before TDC the cylinder can be sealed to thereby compressing the remaining residual steam down to a minute clearance approaching zero, for example, 0.020 inch raising cylinder steam pressure enough to open the steam inlet valve without physical contact between the piston and the steam inlet valve eliminating tappet noise, shock and wear. ## Claims ### Claim 1 A steam engine comprising, a cylinder having a piston that is sealingly and slidably mounted therein at one end of a steam expansion chamber and is operatively connected to a crankshaft, a steam inlet valve that is constructed to seal a valve seat in the engine that communicates between a pressurized steam supply port and the steam expansion chamber, a steam exhaust valve communicating with the steam expansion chamber, a cutoff control valve mounted for reciprocation and positioned to seal communication between the steam expansion chamber and a cutoff timing chamber located in communication with of the steam inlet valve and an electromagnet having an armature operatively associated to move the cutoff control valve at a selected time in a cycle of engine operation for admitting the pressurized steam into the cutoff control chamber to enable the inlet valve to close thereby cutting off the flow of steam to the steam expansion chamber. ### Claim 2 A steam engine comprising, a cylinder having a piston that is sealingly and slidably mounted therein at one end of a steam expansion chamber and is operatively connected to a crankshaft, a steam inlet valve that is constructed to seal a valve seat in the engine that communicates between a steam supply port and the steam expansion chamber, a cutoff control valve mounted for reciprocation in the engine that is constructed and arranged to seal an outlet to the steam expansion chamber and a lifter supported to reciprocate with the piston in a position to close the cutoff control valve as the piston approaches top dead center thereby sealing the steam expansion chamber proximate but prior to an end of the exhaust stroke such that a residual quantity of steam remaining in the steam expansion chamber is compressed by movement of the piston proximate an end of the exhaust stroke to a pressure that opens the inlet valve in response to a force applied to the inlet valve by the steam thus compressed. ### Claim 3 (depends on 2) The steam engine of claim 2 wherein the lifter is mounted on an exhaust valve that is supported by the piston at an end of the piston confronting the steam expansion chamber. ### Claim 4 (depends on 2) The steam engine of claim 2 wherein the lifter is spring mounted on an exhaust valve supported on the piston. ### Claim 5 A steam engine comprising, a cylinder having a piston that is sealingly and slidably mounted therein at one end of a steam expansion chamber and is operatively connected to a crankshaft, a steam inlet valve mounted in the engine that is constructed when in a closed position to seal a valve seat in the engine that communicates between a steam supply port and the steam expansion chamber, a steam exhaust valve mounted for reciprocation in the engine in communication with the steam expansion chamber for exhausting steam therefrom and a spring supported by the exhaust valve in a position to contact a cutoff control valve in the engine communicating with the steam expansion chamber that confronts and is contacted by the spring when the piston approaches a top dead center position thereby closing the cut off control valve. ### Claim 6 (depends on 5) The steam engine of claim 5 wherein the spring is mounted upon the exhaust valve and the exhaust valve is closed by a force applied by the spring. ### Claim 7 (depends on 5) The engine of claim 5 wherein the cutoff control valve seals an opening between the steam expansion chamber and a cutoff timing chamber facing an end of the steam inlet valve that is spaced axially from the steam expansion chamber. ### Claim 8 A steam engine comprising, a cylinder having a piston that is sealingly and slidably mounted therein at an end of a steam expansion chamber and is operatively connected to a crankshaft, a steam inlet valve that is constructed to seal a valve seat in the engine that communicates between a steam supply port and the steam expansion chamber, a steam exhaust valve communicating with the steam expansion chamber, an electromagnet constructed for holding an armature proximate thereto when electric current is supplied thereto, the armature being operatively associated with the steam inlet valve and a cutoff valve that is mounted in the engine for reciprocation and is responsive to actuation by the electromagnet to close the steam inlet valve at a time selected for the cutting off the admission of steam to the expansion chamber. ### Claim 9 (depends on 8) The steam engine of claim 8 wherein at least one spring is connected to the armature for driving the armature away from the electromagnet when the current to the electromagnet is turned off such that the armature is then propelled by the at least one spring away from the electromagnet causing the steam inlet valve to close for cutting off the supply of steam to the steam expansion chamber at a selected time responsive to a termination of the electric current supplied to the electromagnet. ### Claim 10 (depends on 8) The steam engine of claim 8 wherein the engine includes a cutoff timing chamber on an opposite axially spaced end of the inlet valve from the steam expansion chamber, the cutoff timing valve is positioned to seal communication between the cutoff timing chamber and the steam expansion chamber and the armature is constructed and arranged to open the cutoff timing valve when the armature is actuated by the electromagnet to move from a first position to a second position such that steam then flows from the expansion chamber to the cutoff timing chamber whereupon the steam inlet valve closes thereby cutting off a supply of steam to the steam expansion chamber at a selected time responsive to operation of the electromagnet.