Patent ID: 12234752

DETAILED DESCRIPTION

The water-injected steam engine10comprises as its principal components a steam generator12, an engine case14having a first or forward section16and a second or aft section18, a stator20and a rotor22.

The steam generator12comprises a conically-shaped hollow generator body24. At its forward or input end26(the left side in the view ofFIGS.1and3), the generator body has a water injection port or inlet28for the injection of water into the generator body. At its outlet end30, the generator body has a circumferential flange32by which the steam generator is affixed to the forward section16of the engine case. The generator body is open at its outlet end30for the release of steam produced in the steam generator.

A water stream dispersion plug25at the inlet28of the generator body24is arranged to divide the injected water stream into a plurality of streams directed to impact the inner walls of the generator body at predetermined points along its length and circumference. This facilitates rapid vapourization within the generator body.

The steam generator12has heating means for heating the generator body to generate steam from water that is injected into the generator body. In one embodiment the heating means comprises electrical resistance elements34and gas burning nozzles36, positioned radially around the outer perimeter of the generator body in an alternating arrangement.

The forward engine case section16and the aft engine case section18are affixed to the stator20, which is ring-shaped and is arranged between and proximate to the radially outer part of the engine case sections16,18. The stator encircles the rotor22and acts as a spacer between the forward and aft engine case sections16,18.

The steam engine10includes gaskets to prevent the leakage of steam to the outside of the engine. As shown inFIG.3, gaskets23A and23B provide seals between the stator20and the forward engine case section16and the aft engine case section18, respectively. A third gasket23C provides a seal between the steam generator flange32and the forward engine case section16. These are the only two areas that require gaskets as they are the only points of high pressure steam contact where steam could escape without the proper sealing of the parts. In contrast, internal leakage of steam within the engine flows to the interior of the engine case14and does not require seals. The leakage around the outer perimeter of the rotor (i.e., between the rotor and the forward and aft engine case sections) stabilizes the rotor between the engine case sections. The pressure is equal on both sides of the rotor, thereby preventing contact between the rotor and the stationary engine case sections16,18. Likewise, leakage between the rotor and the steam generator does not require to be sealed by a gasket. All such internal leakage of steam ultimately flows into the interior space in the engine case14and is subsequently recovered in the condensation circuit, as explained below.

The rotor22is rotatably supported by the engine case14. The rotor has a shaft38having a forward section40supported by the forward engine case section16and an aft section42supported by the aft engine case section18. The clearances between the rotor and the engine case sections and the stator permit the rotor to rotate freely about its longitudinal axis. The forward section40of the rotor shaft is hollow, forming a steam distribution chamber44within the rotor. The steam distribution chamber44is aligned with the open outlet end30of the steam generator body whereby steam produced in the steam generator flows into the steam distribution chamber44.

The rotor22has a plurality of steam distribution channels46arranged radially about the rotor shaft38. In the illustrated embodiment there are nine channels46, evenly spaced about the rotor shaft and extending radially outward in a plane perpendicular to the longitudinal axis of the rotor shaft. Each steam distribution channel46has an inlet48from the steam distribution chamber44and an outlet50at its radially outer end. The rotor has inner spaces51between adjacent steam distribution channels. These spaces51are open to the interior62of the engine case.

The stator20has a radially inner surface52which defines a plurality of recesses54, spaced evenly around the inner surface of the stator. Each recess54is separated from an adjacent recess54by a short, flat section55at the inner surface52of the stator. Each recess54is shaped so as to have a reaction surface56therein, oriented to be approximately perpendicular to the direction of the flow of steam from the outlets50of the steam distribution channels46. The steam distribution channels46define a curved path such that steam flowing from the outlets50is directed at the inner surface52of the stator20at an angle from the normal. As seen inFIG.2, the curved path of the channels46and the orientation of the outlets50and of the reaction surfaces56is such that, in operation, steam flowing from the steam distribution channels into the stator recesses impacts the reaction surfaces56at an angle of about 90 degrees and causes the outer perimeter58of the rotor to be forced away from the reaction surfaces and rotate the rotor. In the view ofFIG.2, the rotation is in a counterclockwise direction.

The radially outer perimeter58of the rotor has a plurality of pressure relief ports60. These ports provide openings between the stator recesses54and the inner spaces51of the rotor, which are open to the interior space62in the engine case14, whereby steam in the stator recesses54flows into the interior of the engine case. There is one pressure relief port60for each steam distribution channel46. Each pressure relief port60is positioned at a suitable distance behind an adjacent steam distribution channel outlet50(i.e., is positioned clockwise relative to an adjacent outlet50in the view ofFIG.2). The spacing is selected such that steam cannot flow directly from the channel outlet50into the adjacent (i.e., clockwise in the view ofFIG.2) pressure relief port60, and also such that steam does not remain in the stator recess54too long before discharging through the pressure relief port60. In one embodiment, the distance between the trailing edge of each steam distribution channel46at the outer perimeter58of the rotor22and the leading edge of the adjacent pressure relief port60is the span of one recess54. That dimension results in the pressure in the recess54being relieved as soon as the trailing edge of the steam distribution channel passes the forward edge of the recess54.

A plurality of condensation circuit ports64in the aft engine case section18permit the flow of steam from the engine case to a steam condensation circuit. Sufficient ports64are provided to accommodate the volume of steam released into the engine case from the stator recesses54without pressurizing the engine case substantially, and also to allow for a rapid steam cooling and condensing cycle. For example, in the illustrated embodiment there may be three or more condensation circuit ports64, spaced equally apart about the aft engine case section, e.g., 120 degrees apart where there are three ports64.

As shown in the schematic view ofFIG.5, the steam engine10is part of an apparatus72which includes a condensation circuit66for receiving steam from the condensation circuit ports64of the engine case, a water tank68, and a positive displacement pump70for injecting water into the steam generator12. The condensation circuit comprises a condenser and the associated conduits for steam and water. The apparatus includes a controller74for controlling the operation of the engine, the condensation circuit and the pump. For example, the controller, which may be a programmable logic computer (PLC) may regulate the temperature, pressure, speed and power output of the engine, and the injection of water by the pump.

The steam engine10is operated according to the following method. The heating elements34,36are actuated to raise the temperature of the steam generator12to a pre-determined level. Water from the water tank68is injected by the pump70into the steam generator body24through the injection port28, where it is divided into a plurality of streams by the water dispersion plug25and is instantly vaporized to steam. The steam generator is operated at high temperatures to produce a high expansion ratio from liquid to vapour. For example, at 636° F. (356° C.), the expansion ratio of water to steam is 2000:1, producing an absolute pressure of 2002.8 psi (13,809 kPa). Examples of suitable operating temperatures for the steam engine are in the range of 500 to 700° F. (260 to 371° C.), alternatively 600 to 696° F. (316 to 369° C.), though it can operate at substantially lower and higher temperatures. The expanding steam in the steam generator12is forced into the steam distribution chamber44and steam distribution channels46, into the stator recesses54where it impacts the reaction surfaces56, causing rotation of the rotor22. As the rotor rotates, the steam flows from the stator recesses54through the pressure relief ports60into the spaces51in the rotor and into the interior space62of the engine case14, and then out of the engine case through the condensation circuit ports64. In the condensation circuit66the steam is condensed to water and is returned to the water tank. Once a cycle of forcing the steam through the engine and recover condensate in the condensation circuit is complete, the working components of the engine have been heated to the selected operating temperature, which is then maintained during the operation of the engine.

In the operation of the steam engine, power control may be achieved simply by regulating the amount of water injected into the steam generator12in relation to the speed (rpm) set by a throttle. For example, where the steam engine10is used to power a vehicle, if the rpm drops (e.g., when the vehicle is going up a hill), then more water is injected into the steam generator, and if the rpm increases over the throttle settling (e.g., when the vehicle is coasting on level ground or going downhill) then the amount of water injected into the steam generator is reduced. The engine does not slow the vehicle when the power is reduced as there is no compression cycle like a piston engine. In that situation, the rotor would simply be driven by the wheels.

EXAMPLES

Example 1

A steam engine10in accordance with one embodiment of the invention has a diameter of about 8 inches (20.3 cm) and a length (not including the steam generator) of about 6 inches (15.2 cm). The steam generator12is conical with a length of about 8 inches (20.3 cm). The rotor22has a diameter of about 6 inches (15.2 cm) and nine steam distribution channels46. Each reaction surface56is 0.25 square inches (1.61 cm2), for a total reaction surface area as the rotor rotates of 2.25 square inches (14.5 cm2) (9×0.25=2.25). The stator20has thirty-six recesses54, each separated by flat sections55that are 0.024 inches (0.061 cm) wide. The steam engine weighs about 60 pounds (27.2 kg). It operates at a steam temperature in the range of 500 to 700° F. (260 to 371° C.), a steam pressure in the range of 1543 to 3013 psi (10,639 to 20,774 kPa), and an operating speed in the range of 10 to 30,000 rpm. At 1000 rpm, the engine produces power in the range of 165 to 322 horsepower (123 to 240 kW) and torque in the range of 868 to 1695 lb-ft (1180 to 2305 Nm). At a steam pressure of 3000 psi (20,684 kPa) and speed of 10,000 rpm it produces about 5300 horsepower (4698 kW). The steam engine can operate at pressures as low as 300 psi (2068 kPa).

The stator recesses54are approximately 1/16 cubic inch each (1.02 cm3), resulting in 2.268 cubic inches (37.16 cm3) of recess volume that is pressurized and unloaded 324 times per revolution (nine steam distribution channels times thirty-six recesses), which in turn equals 2268 cubic inches (37,166 cm3) of steam at 1000 rpm. One cubic inch (16.4 cm3) of water equals 3000 cubic inches (49,161 cm3) of steam at 700° F. (371° C.) so in order for the engine to operate at 1000 rpm, it requires about one cubic inch (16.4 cm3) of water to be vapourized every minute or about 0.017 cubic inches (0.278 cm3) per second. At 10,000 rpm, the volume is ten times greater or about 1.7 cubic inches (27.8 cm3) of water per second.

Example 2

In another embodiment of the steam engine10, the reaction surface areas56are increased by 50% relative to Example 1 to 0.375 square inches (2.42 cm2), for a total reaction surface area of 3.375 square inches (21.77 cm2). The rotor has the same diameter and number of steam distribution channels as in Example 1. The length of the engine is increased by 0.250 inches (0.64 cm) due to the wider reaction surface area and wider steam distribution channels. The diameter of the forward section40of the rotor shaft is increased to increase the size of the steam distribution chamber, and the aft section42of the rotor shaft is increased for the higher power resulting from the expanded reaction surface area. The engine operates at a steam temperature in the range of 500 to 700° F. (260 to 371° C.) and a steam pressure in the range of 1543 to 3013 psi (10,639 to 20,774 kPa). At 1000 rpm, the engine produces power in the range of 248 to 538 horsepower (185 to 401 kW) and torque in the range of 1085 to 2825 lb-ft (1476 to 3842 Nm).

Throughout the foregoing description and the drawings, specific details have been set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the following claims.