Waste heat engine

An engine includes a radial arrangement of cylinders each having a reciprocating piston with a piston head and a connecting rod pivotally linked to the piston head at an upper end. A lower end of each connecting rod is pivotally linked to a crank disk that is rotatably mounted on a crank arm of a crankshaft. Steam intake valves at each cylinder are momentarily opened by a bearing cam roller that is moved in a circular path by rotation of the crank disk to sequentially engage spring urged cam followers on inboard ends of radially extending valve stems. Low pressure steam or gas is injected into the top of each cylinder, as the intake valves of the cylinders are opened in sequence, thereby forcing the piston in each cylinder through a power stroke to move the crank disk and turn the crankshaft. Angular displacement of each connecting rod through the return stroke of the piston urges an exhaust reed valve on the piston head to an open position, thereby releasing exhaust steam to a condenser chamber. The engine is self-starting and operates in a low pressure, low temperature range, using waste heat from an external source, such as exhaust from an internal combustion engine, burning of refuse (e.g. garbage or other solid waste material) or solar heat.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to steam engines and, more particularly, to a low pressure, low temperature self-starting steam engine that uses waste heat from an external source, and wherein the engine includes a radial arrangement of cylinders with reciprocating pistons for driving rotation of a crankshaft.

2. Discussion of the Related Art

The need to operate at higher temperatures and pressures results in considerable heat loss in conventional steam engines. And, while steam engines are typically larger in size and less efficient than internal combustion engines and diesel engines, (unless operating at high temperatures and pressures) the loss of heat in all types of engines significantly reduces engine efficiency. Accordingly, the ability to harness heat loss during engine operation is highly beneficial and can improve overall engine efficiency. Moreover, waste heat from normal engine operation, as well as other heat sources, can be used in alternative engine designs for generating power. For instance, the energy from waste heat in the operation of an internal combustion engine, refuse burner, or solar energy collector can be used in the operation of an alternative engine for operating an electric power generator.

OBJECTS AND ADVANTAGES OF THE INVENTION

Considering the foregoing, it is a primary object of the present invention to provide a steam engine that operates on low pressure, low temperature steam with the use of waste heat from an external heat source, such as an internal combustion engine, a refuse (e.g. garbage) burner, or a solar heat collector.

If is a further object of the present invention to provide a steam engine that operates on waste heat from an external heat source, and wherein the engine is self-starting.

It is still a further object of the present invention to provide a steam engine having a radial piston configuration, and wherein the engine operates on low pressure, low temperature steam, with an operating pressure of 2 psi to over 200 psi.

It is still a further object of the present invention to provide a steam engine that operates in a low temperature range of 225° F. to 600° F.

It is still a further object of the present invention to provide a steam engine that operates on waste heat from an external heat source, and wherein the engine is useful in the generation of electric power.

It is yet a further object of the present invention to provide a steam engine that operates on low pressure, low temperature steam with the use of waste heat, and wherein the engine is scalable to increase or decrease size and output as needed.

These and other objects and advantages of the present invention are more readily apparent with reference to the detailed description and accompanying drawings.

SUMMARY OF THE INVENTION

The present invention is directed to an engine that includes a radial arrangement of cylinders each having a reciprocating piston with a piston head and a connecting rod pivotally linked to the piston head at an upper end. A lower end of each connecting rod is pivotally linked to a crank disk that is rotatably fitted on a crank arm of a crankshaft. Steam intake valves at each cylinder are momentarily opened by a bearing cam roller that is moved in a circular path by rotation of the crank disk to sequentially engage spring urged cam followers on inboard ends of radially extending valve stems. Low pressure steam or gas is injected into the top of each cylinder, as the intake valves are opened in sequence, thereby forcing the piston in each cylinder through a power stroke to move the crank disk and turn the crankshaft. Angular displacement of each connecting rod through the return stroke of the piston urges an exhaust reed valve on the piston head to an open position, thereby releasing exhaust steam to a condenser chamber. The engine is self-starting and operates in a low pressure, low temperature range, using waste heat from an external source, such as exhaust from an internal combustion engine, burning of refuse (e.g. garbage or other solid waste material) or solar heat.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the several views of the drawings, and initiallyFIGS. 1-3, the waste heat engine of the present invention is shown and is generally indicated as10. An upper portion12of the engine10has a radial arrangement of cylinders20. Low pressure (i.e., generally between 20 psi-200 psi), low temperature (i.e., generally between 225° F. to 600° F.) steam is generated using waste heat from an external heat source (not shown) such as an internal combustion engine, a refuse (e.g., garbage, waste material) burner, or a solar heat collector to generate seam. Water from a condenser30is heated in an external boiler (not shown), using the waste heat to produce steam. The low pressure, low temperature steam is directed through a main line (not shown) that connects to a steam inlet port19on a generally circular manifold18that is supported on the upper portion12of the engine10. Manifold18is structured and disposed to equally distribute the low pressure to intake valves at each cylinder20. A central portion14of the engine10includes the condenser30including a chamber32that is surrounded by a folded star-shaped condenser wall34. A lower portion16of the engine10contains a blower40with a fan blade arrangement42that directs intake air up through cooling ports44at the bottom of the condenser. The blower is driven by rotation of the engine crankshaft24. The cooling air passes through air transfer ducts46that surround the exterior of the folded wall structure34of the condenser30and exits out from blower exhaust ports48, thereby cooling the exhaust steam within the condenser chamber32. A fluid pump36on the engine is driven by rotation of the crankshaft24via a belt drive37. The pump36returns liquid condensate collected in the bottom of the condenser chamber32to the steam generating source (e.g. a boiler), wherein waste heat is again used for generating the low pressure, low temperature steam used in the operation of the engine10.

Referring toFIG. 3, each cylinder20in the radial arrangement includes a reciprocating piston assembly50, including a piston head52that moves in a reciprocating motion within the cylinder20through a full piston stroke. A connecting rod54is pivotally linked to the piston head52and a central crank disk or spider bearing60. More specifically, the connecting rod54of each piston assembly50is pivotally linked at an upper end to the piston head52with a wrist pin bearing56. Similarly, a lower end of the connecting rod54is pivotally linked to the crank disk60with a wrist pin bearing58. The crank disk60is eccentrically fixed to the crankshaft24. More particularly, a crank arm on the crankshaft24is rotatably fitted to the center of the crank disk60so that the center of the crank disk60is offset relative to the longitudinal axis of the crankshaft24. As steam is injected into the top of each cylinder20and the piston52is moved downwardly within the cylinder, the connecting rod54pivots and transmits a force on the crank disk60that is offset relative to the longitudinal central axis on the crankshaft24, thereby causing the crank disk60to move in an orbiting motion around the central longitudinal axis of the crankshaft24, as the crankshaft is turned. Movement on the crank disk60about a full orbital motion, with a complete turn of the crankshaft24, causes the lower pivoting end of each connecting rod54to travel through a circular path, as indicated by the arrow inFIGS. 8A-8D. Restrictor pins64associated with each cylinder are fixed to the crank disk60and are specifically spaced and arranged relative to one another so as to abut against ears59on the lower end of the connecting rod54to limit angular deflection of each connecting rod54.

The steam injection valve assembly is shown inFIGS. 4-7. Referring toFIGS. 4,6and7, a valve head70is located at the top of each cylinder. The valve head includes a valve seat72and a valve cap74. A poppet valve76moves in relation to the valve seat72, between an open position (seeFIG. 6) and a closed position (seeFIG. 7). Steam from the manifold18is directed into a valve chamber78within the valve head70and, when the poppet valve76is opened, the steam is injected through a port80and into the top of the cylinder20. The valve chamber78is surrounded by an insulating material82to maintain the temperature of the steam within the chamber78when the valve76is closed. An elongate valve stem84extends from the poppet valve76inwardly towards a cam follower guide ring86, as seen inFIGS. 4-5B. Referring toFIG. 4, it is seen that the valve stems84are arranged in the same radial configuration as the cylinders20, with the valve stems84extending from the valve heads70at the top of the cylinders and inwardly to the cam follower guide ring86. The valve stems84each extend through a valve stem tube88that is fitted to a seal gland90at the base of the valve head70. A seal packing91and an O-ring92help to discourage escape of the steam from the valve head70. An opposite inboard end of the valve stem tube88is fitted to a attachment tube94that extends into the cam follower guide ring86. Cam followers96fitted to the end of each valve stem84are positioned to extend radially inward into an area87within the cam follower guide ring86at equally spaced intervals relative to the inner circumference of the guide ring. The cam followers96are urged inwardly towards the area within the guide ring by return springs97within the respective attachment tubes94.

A ball bearing cam roller100is connected to the top of the spider bearing and/or a crank throw linked to the crankshaft. The cam roller100orbits about a circular path within the interior area87surrounded by the cam follower guide ring86. A cam counter-balance weight102stabilizes movement of the cam roller100as it moves in the eccentric path within the cam follower guide ring86. The cam roller100is specifically sized, structured and disposed for contacting the cam followers96on the ends of the valve stems84. More particularly, as the cam roller100moves about the orbital path, it is in contact, at all times with at least one cam follower96. Movement of the pistons50to drive the spider bearing60and the crankshaft24serves to also move the cam roller100in its circular path. As the cam roller100contacts each cam follower96, the associated valve stem84is urged axially outward to open the respective poppet valve76, thereby injecting steam into the associated cylinder20. As previously noted, the cam roller100is always in contact with at least one cam follower96, so that at any given moment, steam is being injected into at least one cylinder. As the cam roller100moves away from one cam follower96, it simultaneously contacts the next cam follower96, so that there is an overlap period of steam injection into two adjacent cylinders.

Referring toFIGS. 8A-8D, each piston assembly50within a respective cylinder20includes piston head52with a seal53that engages the inner wall surfaces of the cylinder. As the connecting rod54is angularly displaced during the exhaust stroke (seeFIG. 8D), a valve lifter110on the top end of the connecting rod54, defined by a generally triangular formation with an apex, hits an exhaust reed valve120on the top of the piston head52. The valve lifter110urges the exhaust reed valve120from a relaxed position to a raised position, against the force of the spring action of the reed valve flap which is secured at one end by fastener122to the piston head52. With the reed valve flap120in the open position, as seen inFIG. 8D, the low pressure steam in the upper portion of the cylinder is released through ports130formed through the piston head52, allowing the steam to exhaust into a condenser chamber32of the engine10as the piston50returns to the top dead center position.

Driven rotation of the crankshaft24, by forced movement of the pistons50within the cylinders20, serves to operate an alternator140(or other electric power generator device) via a belt drive or similar linkage between the crankshaft24and the alternator140. Accordingly, operation of the engine10serves to generate electric power.

It is particularly desirable that engine be self-starting. In one preferred embodiment, the radial arrangement of cylinders20includes a total of six cylinders, as seen inFIG. 3. The radial arrangement of six cylinders is particularly beneficial for self-starting and allows for two adjacently positioned cylinders to have their intake valves open during an overlap period so that, at any given moment, two pistons are under force of steam pressure, in a downward power stroke to drive movement of the crank disk and rotation of the crankshaft.

While the present invention has been shown and described in accordance with a preferred and practical embodiment, it is recognized that departures from the instant disclosure are fully contemplated within the spirit and scope of the invention as defined in the claims which follow.