High efficiency steam engine and impact-free piston operated valves therefor
AssigneeThermal Power Recovery LLC
InventorJames V. Harmon, Sr.
Life of this patent
Estimating the term…
Abstract
A high efficiency variable cutoff uniflow steam engine with piston operated valves has an exhaust valve that is held open by a spring during the exhaust stroke but is closed at an end of the exhaust stroke by the piston compressing steam in a compartment associated to act on the exhaust valve. The piston continues to move in the same direction a short distance toward top dead center (TDC) compressing a small residual quantity of steam in the cylinder above the piston during the remaining fraction of the exhaust stroke with sufficient pressure to open the steam inlet valve by steam pressure without an impact caused by physical contact with the piston.
Claims18
A steam engine in which at least one valve is operated by piston movement comprising:
- a cylinder having a piston slidably and sealingly mounted therein and operatively connected to a crankshaft;
- a cylinder head at one end of the cylinder that includes at least one valve therein which comprises a steam inlet valve slidably mounted and yieldably biased to move in the direction of the piston to a closed position on a valve seat in the cylinder head;
- a steam exhaust valve that is slidably mounted within the engine and is yieldably biased to an open position during an exhaust stroke;
- a valve actuation assembly;
- wherein the valve actuation assembly comprises:
- a steam compression compartment defined between a plunger and a recess within the engine that is closed at one end and is open at the other end, the plunger being aligned to enter the recess through the open end of the recess for pressurizing steam within the steam compression compartment;
- wherein the valve actuation assembly is operatively associated between the piston and the cylinder head;
- the valve actuation assembly is constructed and arranged such that the plunger and the recess remain out of engagement with one another during an exhaust stroke until entry of the plunger into the recess proximate an end of the exhaust stroke;
- whereupon steam supplied to the engine that is located in the steam compression compartment within the recess is pressurized due to a movement of the piston and the entry of the plunger into the recess;
- and
- whereupon the pressurized steam within the steam compression compartment closes the exhaust valve and opens the inlet valve proximate the end of the exhaust stroke in the absence of physical contact between both a) the closed end of the recess and the plunger, and b) between the piston and the inlet valve.
A method of activating a steam engine valve responsive to piston movement comprising steps of:
- providing a steam engine cylinder having a piston therein, a cylinder head that is located at one end of the cylinder and a steam expansion chamber between the cylinder head and the piston;
- providing a steam inlet valve comprising a poppet valve that is held by a yieldable biasing force to a closed position and a poppet exhaust valve wherein both valves communicate with the steam expansion chamber;
- maintaining the exhaust valve open during an exhaust stroke as the piston moves toward the cylinder head;
- closing the exhaust valve proximate but prior to an end of an exhaust stroke whereby a residual quantity of steam is then compressed in the steam expansion chamber during a terminal fraction of the exhaust stroke prior to top dead center;
- and
- maintaining the piston clearance at top dead center sufficiently small that the steam is compressed in the expansion chamber during the terminal fraction of the exhaust stroke to a pressure sufficient to at least partially open the inlet valve against the yieldable biasing force on the inlet valve in the absence of a physical contact force applied by the piston to the inlet valve.
A steam engine comprising:
- at least a steam inlet valve and a steam exhaust valve is operated by a piston movement to admit and to discharge steam respectively;
- a cylinder having a piston slidably and sealingly mounted therein and operatively connected to a crankshalt;
- wherein the steam inlet valve comprises:
- a valve body slidably mounted in a bore within the engine with at least one port in the bore for admitting the steam into the bore and a cutoff control for closing the steam inlet valve at a selected fraction of a power stroke of the piston;
- and
- a compression ring around the inlet valve body that is positioned between the port in the bore and a valve seat for the inlet valve body when the valve body is in contact with the valve seat thereby inhibiting a premature transfer of steam into a seal area between the valve body and the valve seat while the inlet valve is closed.
Dependencies are inferred from the claim text.