US20190120054A1

US20190120054A1 - Rotary steam motor

Info

Publication number: US20190120054A1
Application number: US16/165,359
Authority: US
Inventors: Patrick Paul; John Paul Beckman
Original assignee: MicroSteam Inc dba Practical steam
Current assignee: MicroSteam Inc dba Practical steam
Priority date: 2017-10-20
Filing date: 2018-10-19
Publication date: 2019-04-25
Also published as: WO2019077583A1

Abstract

Provided herein is a rotary steam motor comprising an inlet assembly, a rotor assembly, and an exhaust assembly. The inlet assembly includes an inlet port and an inlet housing, the inlet port being configured to allow steam to enter the inlet housing. The rotor assembly includes a rotor having a plurality of vane slots, a support shaft, and a plurality of vanes, wherein the support shaft is configured to rotate with the rotor, and each vane is configured to slidably engage within a respective vane slot. The exhaust assembly includes an exhaust port and an exhaust housing, the exhaust port being configured to allow steam to exit the exhaust housing. The rotary steam engine further comprises a variable duration throttle assembly, wherein the variable duration throttle assembly is configured to regulate the flow of steam into the rotor assembly from the inlet assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 62/575,134, titled Rotary Steam Engine, filed on Oct. 20, 2017, which is incorporated herein in its entirety by reference.

BACKGROUND

Many forms of power generation in thermal-fluid systems use engines for converting expansive pressure into mechanical and/or electrical power. Various engines have specific advantages and disadvantages when compared. Turbine engines offer advantages of high speed operation and high power density. However, turbines are relatively large, expensive, and often suffer from an inability to operate efficiently. Other engines may be able to operate more efficiently, but typically operate at very slow speeds resulting in relatively low power outputs. A desirable combination is a relatively small, inexpensive, high speed engine design that allows for efficient operation at relatively high power outputs.
Applicant has identified a number of additional deficiencies and problems associated with conventional systems and methods. Through applied effort, ingenuity, and innovation, many of these identified problems have been solved by developing solutions that are included in embodiments of the present invention, examples of which are described in detail herein.

BRIEF SUMMARY OF THE INVENTION

The present disclosure relates to a rotary steam engine such as may be used for the generation of electrical power. In one aspect, a rotary steam engine is provided. The rotary steam engine may comprise an inlet assembly including an inlet port and an inlet housing, the inlet port being configured to allow steam to enter the inlet housing; a rotor assembly including a rotor, a support shaft, and a plurality of vanes, wherein the support shaft is configured to rotate with the rotor, and the rotor includes plurality of vane slots such that each vane is configured to slidably engage within a respective vane slot; an exhaust assembly including an exhaust port and an exhaust housing, the exhaust port being configured to allow steam to exit the exhaust housing; and a variable duration throttle assembly. The rotor assembly may be configured to receive steam from the inlet assembly, and the exhaust assembly may be configured to receive steam from the rotor assembly. In addition, the variable duration throttle assembly may be configured to regulate the flow of steam into the rotor assembly from the inlet assembly so as to provide substantially constant pressure expansion from the intake assembly through the exhaust assembly.
In some embodiments, the throttle assembly may further comprise a rotating throttle plate and a throttle port, wherein the throttle plate is configured to selectively cover at least a portion of the throttle port. Some embodiments may further comprise a throttle control configured to selectively rotate the throttle plate. In some embodiments, the throttle control may be configured to rotate the throttle plate via a gear driven throttle control mechanism. Some embodiments may further comprise a generator assembly configured to convert rotating motion into electrical power, wherein the generator assembly is operably connected to the support shaft.
In some embodiments, the rotor assembly may define at least one intake area, in which steam enters the rotor assembly from the inlet assembly, and at least one corresponding exhaust area, in which steam exits the rotor assembly to the exhaust assembly. In some embodiments, a central axis of the rotor and support shaft may be offset with respect to a central axis of an inner surface of the rotor housing. In some embodiments, the rotor assembly may define two intake areas, in which steam enters the rotor assembly from the inlet assembly, and two corresponding exhaust areas, in which steam exits the rotor assembly to the exhaust assembly. In some embodiments, a central axis of the rotor and support shaft may be substantially aligned with respect to a central axis of an inner surface of the rotor housing. In some embodiments, the rotor assembly may further define at least one expansion area located between the at least one intake area and the at least one exhaust area.
As a result of the configurations described above, the present disclosure provides a rotary engine that is configured for the introduction of steam (or other compressible gas) into an expansion area so as to translate the energy of the expanding steam into rotational force at the supply pressure and maintain substantially constant expansion from intake through exhaust to maximize efficiency. In addition, the throttle assembly allows the pressure drop in the inlet to occur only in the expansion area and thus captures the energy from the steam enthalpy more efficiently.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 illustrates an isometric view of a rotary steam engine according to an example implementation of the present disclosure;

FIG. 2 shows front view of a rotary steam engine according to an example implementation of the present disclosure;

FIG. 3 shows a top view of a rotary steam engine according to an example implementation of the present disclosure;

FIG. 4 shows a exploded side view of a rotary steam engine according to an example implementation of the present disclosure;

FIG. 5 shows a schematic drawing of a rotor assembly according an example implementation of the present disclosure;

FIG. 6 shows a variable duration throttle control assembly according to an example implementation of the present disclosure; and

FIG. 7 shows a schematic drawing of a rotor assembly according another example implementation of the present disclosure.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. It should be understood that while various elements of the rotary steam engine are described in detail below, various other elements, while not described, may be included in example implementations of the invention, as would be understood by one of skill in the industry. Such elements may include, but need not be limited to, various housings, manifolds, shafts, fasteners, bushings, seals, motors, gears, spacers, gaskets, fans, generators and other mechanical components and/or mechanisms, as well as various electronic components and systems.
Some embodiments detailed herein include assemblies for use in thermal-fluid and expansion engines, including, for example, steam engines. As detailed herein, embodiments of the present disclosure shown in FIGS. 1-7 may control the flow of a working fluid (e.g., steam) under pressure into and/or out of a rotor assembly to facilitate operation of a drive member (e.g., a support shaft). Although the following description employs steam as the working fluid, it should be noted that the present disclosure is applicable to any compressible gas. As such, the present disclosure has broad applicability and should not be limited to any one particular compressible gas. Thus, in various embodiments the term “steam” as used herein may be substituted with any other applicable compressible gas.
For example, the working fluid of the engine may be an organic and/or inorganic fluid, either naturally occurring or manmade. The working fluid may include, for example: Chlorofluorocarbon (CFC) (e.g. R-11, R-12); Hydrofluorocarbons (HFC) (e.g. R-134a, R-245fa); Hydrochlorofluorocarbon (HCFC) (e.g. R-22, R-123); Hydrocarbons (HC) (e.g. Butane, methane, pentane, propane, etc.); Perfluocarbon (PFC); Basic organic compounds (Carbon dioxide, etc.); Inorganic compounds (e.g. Ammonia); Elements (Hydrogen, etc.), or a combination thereof, amongst others. A preferred working liquid is pressurized steam.
FIG. 1 shows an isometric view of a rotary steam engine 100 according to an example implementation of the present disclosure. In various implementations, the rotary steam engine 100 of the illustrated implementation may include an intake assembly 120, a rotor assembly 140, and an exhaust assembly 180. As shown in FIGS. 2-4, the inlet assembly 120 may include an inlet port 122 configured to receive steam from a steam supplying source and a variable duration throttle assembly 130 configured to control the flow of steam into the rotor assembly 140. In various implementations, the steam supplying source may be any source capable of delivering steam to the rotary steam engine at a relatively high pressure. In one implementation, the steam supplying source may be a steam boiler or steam generator. In another example implementation, the steam supplying source may be a separate manufacturing operation that generates or outputs steam at a relatively high pressure. Whatever the source, in various implementations, the generated steam may be delivered to the inlet assembly 120 of the rotary steam engine 100 in accordance with a variety of industry methods and equipment, including, for example, via various hosing, pipes, lines, etc. configured to handle the inlet steam. In some embodiments, for example, the inlet steam pressure may be in the range of approximately 100-250 psig at approximately 1,000-20,000 lb/hr flow.
As also shown in FIGS. 2-4, inlet steam that enters the inlet assembly 120 is delivered to the rotor assembly 140. In the illustrated implementation, the rotor assembly 140 includes a rotor housing 142, a support shaft 144, and a rotor 146 that includes a plurality of vanes 148. The plurality of vanes 148 slidably engage with a plurality of rotor vane slots radially disposed about the rotor 146. In various implementations, the steam engine of the present disclosure may comprise an “unbalanced” design in which the respective profiles of the rotor and an inner surface of the rotor housing are substantially circular and a central axis of the rotor and support shaft is offset with respect to a central axis of the inner surface of the rotor housing. The implementation of the present disclosure shown in FIG. 5 illustrates an example of an “unbalanced” design. In the illustrated implementation, the rotor 146 includes eight vane slots 150 that are radially disposed and substantially equally spaced about a circumference of the rotor 146. Eight corresponding vanes 148 are disposed within the vane slots 150, such that each vane 148 is slidably engaged within a corresponding vane slot 150. It should be noted that in other implementations of the present disclosure, any number of vane slots and vanes may be used, including as few as two.
In various implementations, the size, shape, and material of the vanes and vane slots may be configured such that the centrifugal force generated by the rotation of the rotor allows the vanes to slide outward and contact an inner surface of the rotor housing. In the implementation illustrated in FIG. 5, centrifugal force caused by the rotation of the rotor 146 causes the vanes 148 to slide outward within the vane slots 150 such that the vane ends contact an inner surface 152 of the rotor housing 142. In such a manner, during a full rotation of the rotor 146, each vane 148 slides inward from a minimum extension, where the rotor 146 is closest to the inner surface 152 of the rotor housing 142, outward to a maximum extension, where the rotor 146 is farthest from the inner surface 152 of the rotor housing 142. Because the centrifugal force causes the ends of the vanes 148 to contact the inner surface 152 of the rotor housing 142, a plurality of cavities 154 are created between the rotor 146 and successive vanes 148. As such, the volume of each cavity increases and decreases during a rotation of the rotor 146. In particular, the volume of a cavity 154 increases from a minimum volume, wherein the cavity 154 is proximate a “near point” (i.e., where the rotor 146 is closest to the inner surface 152 of the rotor housing 142), to a maximum volume, wherein the cavity is proximate a “far point” (i.e., where the rotor 146 is farthest from the inner surface 152 of the rotor housing 142), and back to a minimum volume, wherein the cavity 154 is proximate the near point. It should be noted that throughout this description, the word “point” should be interpreted so as to cover a position, point, or general area.
As shown in FIG. 5, the rotor assembly 140 also defines an intake area 156 in which the steam enters the rotor assembly 140, an expansion area 158 in which the steam expands, and an exhaust area 160 in which the steam is exhausted into the exhaust assembly 180. With reference to the rotation of the rotor 146, in the illustrated implementation, the intake area 156 occurs just past the near point, but before the far point, the expansion area 158 occurs between the end of the intake area 156 and the far point, and the exhaust area 160 occurs between the far point and the near point.
In such a manner, when a cavity 154 defined by the rotor 146 and successive rotor vanes 148 is proximate the intake area 156, high pressure steam enters from the side of the rotor housing 142 to fill the cavity 154. The steam pushes on the vanes 148 such that the force on the vanes 148 causes the rotor 146 to rotate. As the rotor 146 rotates and the cavity 154 enters the expansion area 158, the volume of the cavity increases and the pressure of the steam decreases. When the cavity 154 enters the exhaust area 160, the volume of the cavity decreases and the vanes 148 push the low pressure steam through the rotor housing 142 and into the exhaust assembly 180. In various implementations, the rotation of the support shaft may be converted to electrical energy via a variety of devices configured to convert mechanical energy into electricity, including via use of a generator coupled to the support shaft.
As described above, while high pressure steam is supplied to the intake assembly 120 via the intake port 122, the flow of the high pressure steam into the rotor assembly 140 is regulated by the variable duration throttle control assembly 130. In various implementations, the variable duration throttle control assembly may be adjustable, and in some implementations may be continuously adjustable, so as to control the rate and/or volume of the intake steam into the rotor assembly. In various implementations the throttle control assembly may be adjustable via a gear driven throttle control mechanism. For example, in the illustrated implementation, the variable duration throttle control assembly 130 is adjustable via a worm and sector gear arrangement. In various implementations, adjustment of the variable duration throttle control assembly may be manual or may occur according to a program and/or in response to various measurements and/or feedback relating to the performance of the rotary steam engine. As such, operation of the variable duration throttle control assembly adjustment mechanism may be controlled via an electronic controller.
An example implementation of the throttle control assembly 130 is shown in FIG. 6. As shown in the figure, the variable duration throttle assembly 130 may include a rotating throttle plate having a throttle plug 132 attached thereto. An inlet port 134 may also be defined in the side of the inlet housing 122 through which the inlet steam exits the inlet assembly 120 and enters the rotor assembly 140. In various implementations, the throttle plate may be configured to rotate such that at least a portion of the throttle port is covered. In such a manner, the throttle plate may be rotated anywhere between a minimum position, is which a relatively large portion of the throttle port is covered and a minimum throttle inlet area is created, and a maximum position, in which the throttle port is open and a maximum throttle inlet area is created. In the illustrated implementation, the throttle plug 132 is configured to rotate within the throttle port 134 such that the throttle plug 132 “bottoms out” at the minimum and maximum throttle inlet area conditions. Therefore, in some embodiments, the throttle port may be completely covered or nearly completely covered at the minimum position, with some possible leakage occurring due to mechanical clearances.
In various other implementations, the steam engine of the present disclosure may comprise a “balanced” design in which a central axis of the rotor and support shaft is substantially aligned with respect to a central axis of the inner surface of the rotor housing. In some of these implementations, the profile of the rotor may be substantially circular and the profile of the inner surface of the rotor housing may be substantially oval or oblong. FIG. 7 illustrates an example implementation of a “balanced” design. In the illustrated implementation, the rotor 246 includes eight vane slots 250 that are radially disposed and substantially equally spaced about a circumference of the rotor 246. Eight corresponding vanes 248 are disposed within the vane slots 250, such that each vane 248 is slidably engaged within a corresponding vane slot 250. It should be noted that in other implementations of the present disclosure, any number of vane slots and vanes may be used, including as few as two.
In various implementations, the size, shape, and material of the vanes and vane slots may be configured such that the centrifugal force generated by the rotation of the rotor allows the vanes to slide outward and contact an inner surface of the rotor housing. In the implementation illustrated in FIG. 7, centrifugal force caused by the rotation of the rotor 246 causes the vanes 248 to slide outward within the vane slots 250 such that the vane ends contact an inner surface 252 of the rotor housing 242. In such a manner, during a full rotation of the rotor 246, each vane 248 slides between a first minimum extension, a first maximum extension, a second minimum extension, and a second maximum extension (i.e., between minimum and maximum extensions two times). In particular, in the first half rotation of the rotor 246, each vane 248 rotates from a first minimum extension, where the rotor 246 is close to a portion of the inner surface 252 of the rotor housing 242, outward to a first maximum extension, where the rotor is far from the inner surface 252 of the rotor housing 242, and then to a second minimum extension, where the rotor 246 is close to another portion of the inner surface 252 of the rotor housing 242. Likewise, during the second half rotation of the rotor 246, each vane 248 rotates from the second minimum extension, where the rotor 246 is close to the second portion of inner surface 252 of the rotor housing 242, outward to a second maximum extension, where the rotor is far from the inner surface 252 of the rotor housing 242, and then back to the first minimum extension, where the rotor 246 is close to the initial portion of the inner surface 252 of the rotor housing 242. Because the centrifugal force causes the ends of the vanes 248 to contact the inner surface 252 of the rotor housing 242, a plurality of cavities 254 are created between the rotor 246 and each successive vane 248. As such, the volume of each cavity 254 increases and decreases with each half rotation of the rotor 246. In particular, the volume of the cavity increases from a first minimum volume, wherein the cavity 254 is proximate a first near point (i.e., where the rotor 246 is close to a portion of the inner surface 252 of the rotor housing 242), to a first maximum volume, wherein the cavity 254 is proximate a first far point (i.e., where the rotor 246 is far from the inner surface 252 of the rotor housing 242), back to a second minimum volume, wherein the cavity 254 is proximate a second near point (i.e., where the rotor 246 is close to another portion of the inner surface 252 of the rotor housing 242), to a second maximum volume, wherein the cavity 254 is proximate a second far point (i.e., where the rotor 246 is far from the inner surface 252 of the rotor housing 242, and back to the first minimum volume, wherein the cavity 254 is proximate the first near point (i.e., where the rotor 246 is close to the initial portion of the inner surface 252 of the rotor housing 242).
Because the implementation illustrated in FIG. 7 comprises a “balanced design,” the rotor assembly 240 also defines two opposite intake areas 256, in which the steam enters the rotor assembly 240, two opposite expansion areas 258, in which the steam expands, and two opposite exhaust areas 260, in which the steam is exhausted into the exhaust assembly 280. With reference to the rotation of the rotor 246 in the illustrated implementation, the first intake area 256′ occurs just past the first near point, but before the first far point, the first expansion area 258′ occurs between the end of the first intake area 256′ and the first far point, and the first exhaust area 260′ occurs after the end of the first expansion area 258′ but before the second near point. The second intake area 256″ occurs just past the second near point but before the second far point, the second expansion area 258″ occurs between the end of the second intake area 256″ and the second far point, and the second exhaust area 260″ occurs after the end of the second expansion area 258″ but before the first near point.
In such a manner, when cavities 254 defined by the rotor 246 and successive rotor vanes 248 are proximate the intake areas 256′, 256″ high pressure steam enters from the side of the rotor housing 242 to fill the cavities 254. The steam pushes on the vanes 248 such that the force on the vanes 248 causes the rotor 246 to rotate. As the rotor 246 rotates and the cavities 254 enter the expansion areas 258′, 258″, the volume of the cavities increases, and the pressure of the steam decreases. When the cavities 254 enter the exhaust areas 260′, 260″, the volume of the cavities decreases and the vanes 248 push the low pressure steam through the rotor housing 242 and into the exhaust assembly 280. In various implementations, the rotation of the support shaft may be converted to electrical energy via a variety of devices configured to convert mechanical energy into electricity, including via use of a generator coupled to the support shaft.
As described above, while high pressure steam is supplied to the intake assembly via the intake port, the flow of the high pressure steam into the rotor assembly is regulated by a variable duration throttle control assembly. In various implementations, the variable duration throttle control assembly may be adjustable, and in some implementations may be continuously adjustable, so as to control the rate and/or volume of the intake steam into the rotor assembly. In various implementations the throttle control assembly may be adjustable via a gear driven throttle control mechanism.
In one implementation, an example of a variable duration throttle control assembly for use with a balanced rotary steam engine design may look similar to the variable duration throttle control assembly shown in FIG. 7 for use with the unbalanced design, except that the control assembly may include a second throttle port, and, in some implementations, a second throttle plug. As such, the throttle plate of an example of a variable duration throttle assembly for use with a balanced steam engine may be configured to rotate such a portion of the respective throttle ports is covered. In such a manner, the throttle plate may be rotated anywhere between a minimum position, in which a relatively large portion of the throttle ports are covered and a minimum throttle inlet area is created, to a maximum position in which the throttle ports are open, and a maximum throttle inlet area is created. In addition, while in one implementation of a balanced design the intake assembly may include two separate intake ports, another implementation of a balanced design may include a single intake port that includes a splitter configured to split the intake flow into two separate paths, each leading to a respective throttle port. Therefore, in some embodiments, the throttle ports may be completely covered or nearly completely covered at the minimum position, with some possible leakage occurring due to mechanical clearances.
As shown in the figures, in various implementations inlet steam that enters an inlet assembly travels through a rotor assembly and exits the rotary steam engine through an exhaust port that is part of an exhaust assembly. For example, in the implementation illustrated in FIGS. 1-4, the exhaust assembly 180 includes an exhaust housing 184 and an exhaust port 182. In various implementations, the exhaust steam may exit the exhaust assembly and be released to the atmosphere or may travel to additional equipment for further processing. For example, in one example implementation, the exhaust steam may travel to a condenser configured to condense the exhaust steam into liquid form (i.e., a condensate) that, in some implementations, may be further processed, such as to be recycled into the steam supplying source. In various implementations, the exhaust steam may be delivered in accordance with a variety of industry methods and equipment, including, for example, via various hosing, pipes, lines, etc. configured to handle the exhaust steam.
Various implementations of the rotary steam engine disclosed herein may provide many advantages over prior systems. For example, the disclosed rotary steam engine may be configured to provide substantially constant steam expansion from the intake cycle through the exhaust cycle. In addition, the variable duration throttle control assembly of the disclosed steam engine may be configured to provide full intake steam pressure into the rotor assembly, such that the intake steam pressure does decrease until it the steam expands in the intake area. Many existing steam engines and steam turbines experience additional pressure drop in areas prior to rotor intake due to the configuration of their throttle valves.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these embodiments of the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the embodiments of the invention are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. While some drawings and description may omit features described elsewhere for simplicity of explanation, it is understood that these features may nonetheless be present in any of the embodiments in any combination or configuration, as detailed above. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A rotary steam motor comprising:

an inlet assembly including an inlet port and an inlet housing, the inlet port being configured to allow steam to enter the inlet housing;

a rotor assembly including a rotor, a support shaft, and a plurality of vanes, wherein the support shaft is configured to rotate with the rotor, and the rotor includes plurality of vane slots such that each vane is configured to slidably engage within a respective vane slot;

an exhaust assembly including an exhaust port and an exhaust housing, the exhaust port being configured to allow steam to exit the exhaust housing; and

a variable duration throttle assembly,

wherein the rotor assembly is configured to receive steam from the inlet assembly, and the exhaust assembly is configured to receive steam from the rotor assembly, and

wherein the variable duration throttle assembly is configured to regulate the flow of steam into the rotor assembly from the inlet assembly so as to provide substantially constant pressure expansion from the intake assembly through the exhaust assembly.

2. The rotary steam motor of claim 1, wherein the throttle assembly further comprises a rotating throttle plate and a throttle port, and wherein the throttle plate is configured to selectively cover at least a portion of the throttle port.

3. The rotary steam motor of claim 2, further comprising a throttle control configured to selectively rotate the throttle plate.

4. The rotary steam motor of claim 3, wherein the throttle control is configured to rotate the throttle plate via a gear driven throttle control mechanism.

5. The rotary steam motor of claim 1, wherein the rotor assembly defines at least one intake area, in which steam enters the rotor assembly from the inlet assembly, and at least one corresponding exhaust area, in which steam exits the rotor assembly to the exhaust assembly.

6. The rotary steam motor of claim 5, wherein a central axis of the rotor and support shaft is offset with respect to a central axis of an inner surface of the rotor housing.

7. The rotary steam motor of claim 5, wherein the rotor assembly defines two intake areas, in which steam enters the rotor assembly from the inlet assembly, and two corresponding exhaust areas, in which steam exits the rotor assembly to the exhaust assembly.

8. The rotary steam motor of claim 7, wherein a central axis of the rotor and support shaft is substantially aligned with respect to a central axis of an inner surface of the rotor housing.

9. The rotary steam motor of claim 5, wherein the rotor assembly further defines at least one expansion area located between the at least one intake area and the at least one exhaust area.

10. The rotary steam motor of claim 1, further comprising a generator assembly configured to convert rotating motion into electrical power, and wherein the generator assembly is operably connected to the support shaft.