Apparatus for extracting useful energy from superheated vapor

Superheated vapor actuated power generating devices in the past have extracted the energy of a working fluid which had been sufficiently heated to generate the superheated vapor phase of the working fluid by sequentially expanding the superheated vapor, isentropically discharging the vapor to a condenser for liquefaction, converting the extracted energy to useful work such as rotational output, and utilizing a portion of the rotational output to transfer the liquefied working fluid to means for reheating the working fluid and repeating the cycle.

In DE-C-41 477 a power generating device is already known in which there is a high pressure piston and cylinder assembly, the high pressure piston being mechanically linked to the piston of a low pressure piston and cylinder assembly. The two pistons jointly drive a working shaft. In this prior art there is a selectively closable communication between a part of the high pressure cylinder and a part of the low pressure cylinder said part of the low pressure cylinder is also in selective communication with a condenser. Although such features can be found in the present invention it will be realized, from the description that now follows, that the aforesaid features were used in a totally different operative concept to that of the present invention and that, as a result the apparatus of the prior art was not capable of extracting and converting the useful work output of vapor to the same extent as the present invention. Thus, for example, in the prior art the arrangement is such that steam is first fed to the high pressure cylinder to that side of the piston therein from which the mechanical linkage to the low pressure piston extends. As steam is admitted to cause a forward working stroke, the communication between the two cylinders is closed and the high pressure piston is driven towards an end of the high pressure cylinder that is closed apart from a one way valve there that allows any vapor trapped between the high pressure piston and said end to escape.

During this forward working stroke, the volumes of the low pressure cylinder on opposed sides of the low pressure piston are in communication with each other and the communication between the aforesaid part of the low pressure cylinder with the condenser is open.

When the high pressure piston reaches the end of the said forward working stroke, a valve closes to shut off the steam supply to the high pressure cylinder and the communication between the two cylinders is then opened. At the same time the communication between the aforesaid part of the low pressure cylinder with the condenser closes and this closure serves also to close the communication between the cylinder volumes on opposed sides of the low pressure piston.

The steam that is now in the high pressure cylinder expands into the low pressure cylinder and as the low pressure piston is larger in diameter than the high pressure piston the pistons jointly perform a return working stroke. During the return working stroke the volume of the low pressure cylinder into which steam is not expanding from the high pressure cylinder remains in communication with the condenser and this is stated to produce a vacuum in said volume that aids said return stroke.

At the commencement of this return working stroke, however, the aforesaid one-way valve in the high pressure cylinder will automatically close. Thus, as the high pressure piston performs its return stroke a vacuum will exist behind said piston and such a vacuum will, of course, greatly reduce the efficiency of the system.

A major object of the present invention is to provide a mechanical structure which minimizes or eliminates inherent inefficiencies of the prior art and enhances the method of extracting and converting the useful work output of vapor actuated power generating device.

The present power generating device comprises:

• a source of superheated vapor;
• a working shaft;
• a first piston and cylinder assembly located at least in part in a high pressure vessel containing superheated vapor, said first piston being operatively linked to the working shaft and having one of its faces continuously exposed to the superheated vapor whilst its other face is in selective fluid communication with the source of superheated vapor; and
• a second piston and cylinder assembly located within the confines of a condenser for condensing the superheated vapor, said second piston being mechanically linked with the first piston and said second cylinder being in selective and separate fluid communication with both the condenser and with that side of the first piston that is in selective fluid communication with the superheated vapor.

The high pressure vessel contains one or more high pressure cylinder and piston assemblies and a rotational output shaft with connection means from the high pressure pistons. In particular the bottom face of each high pressure cylinder is directly exposed to the constant high pressure of the superheated vapor within the high pressure vessel volume and the aggregate internal volume of the high pressure cylinders within the high pressure vessel is greatly exceeded by the total volume of the high pressure vessel which allows the high pressure to be maintained within the high pressure volume.

Slide valves on the outside periphery of the high pressure cylinders permit the volume contiguous to the top face of the high pressure pistons to selectively be in direct communication with the high pressure volume, be isolated, or be discharged to a lower pressure volume being created by the sweep of a larger diameter low pressure piston which is axially connected to the high pressure piston by a common connecting rod causing it to move in synchronization with the high pressure piston. When the volume contiguous to the top face of the high pressure piston is in communication with the high pressure volume, the pressure on each face of the high pressure piston is equalized resulting in intake of the high pressure superheated vapor with a minimum of negative work being performed. Adiabetic isentropic expansion of the superheated vapor is accomplished by isolating the volume contiguous to the high pressure piston at say 145 degrees of rotation from top dead center of the high pressure pistons travel by activating the slide valve to a closed position. The arrangement of the present invention allows the adiabatic isentropic expansion of the superheated vapor to occur in the isolated cylinder volume contiguous to the top piston face in such a manner as to not overload the adiabatic isentropic expansion process with more heat energy than it can efficiently utilize. When the slide valve is activated at say 180 degrees of rotation from top dead center so as to allow discharge of the expanded vapor to a larger and lower pressure volume contiguous to the top face of the larger diameter low pressure piston, isobaric forces exerted on the bottom side of the high pressure piston by the constant high pressure of the superheated vapor maintained in the high pressure vessel causes movement of the piston toward top dead center or 360 degrees of rotation.

The high pressure piston, low pressure piston and injector piston are rigidly connected by a common connecting rod. As a result of the low pressure piston and cylinder assemblies being located within one of the low pressure vessel volumes which also serves as a system condenser, the top face of the low pressure pistons are subjected to the lowest pressure of the power generating device's closed system. Due to the direct connection of the high and low pressure pistons, the pressure differential from the bottom face of the high pressure piston to the top face of the low pressure is maximized allowing maximum forces to be exerted on the work producing pistons and thereby maximizing efficiency and avoiding unnecessary energy waste needlessly introduced in prior art embodiments.

The volume contiguous to the bottom face of the low pressure piston can be selectively isolated, in direct communication with the discharge of the top volume contiguous to the face of the high pressure piston, or exhausted directly to the low pressure vessel volume/condenser with the use of a similar slide valve as used on the high pressure pistons. When the slide valve is actuated so as to receive the discharge from the volume contiguous to the high pressure cylinder, a larger cylinder volume is swept by the larger diameter low pressure piston which creates a lower pressure and results in complete evacuation of the vapor from the volume contiguous to the top face of the high pressure piston. The flow of the vapor from the volume contiguous to the top face of the high pressure piston is caused to expand rapidly within the volume contiguous to the bottom face of the low pressure cylinder as a result of a unique swirl chamber consisting of concave formations of the low pressure piston's bottom face and the low pressure cylinder's end wall thereby also efficiently utilizing the kinetic forces of the vapor flow. When the slide valve is actuated so as to isolate the volume contiguous to the bottom face of the low pressure piston face, further expansion of the working fluid vapor is accomplished through the travel of the piston to top dead center. After this expansion, the slide valve is actuated so as to allow the expanded vapor contiguous to the bottom face of the low pressure cylinder to be exhausted directly to the low pressure vessel/condenser volume and liquefaction of the expanded working vapor is affected by the removal of heat by the condenser. When exhausting to the low pressure vessel/ condenser volume, the pressure differential across the low pressure piston is equalized and discharge of the expanded vapor is to the power generating device's lowest pressure which again minimizes wasted energy.

The injector pistons are also located within one of the low pressure vessel/condenser volume and axially connected to the low pressure piston by the common connecting rod of the high and low pressure pistons. The injector piston draws from the liquefied working fluid reservoir and positively displaces the working fluid to a reservoir with a heat source. With the injector piston and cylinder assembly being located within one of the power generating device's condensers, cavitation and vapor lock experienced in the prior art is completely avoided by the heat removal accomplished by the condenser which surrounds the injector piston and cylinder assembly.

If the working fluid is one of the volatile fluids with a low boiling point, low grade heat sources such as waste or cogenerated, solar, or other similar low grade heat sources can be used singularly or in combination to cause the liquefied working fluid to undergo another phase change to a saturated vapor. A second reservoir and heat source could be used to superheat the saturated vapor with conventional means and controls being used to provide such heat as necessary to provide superheated vapor in sufficient amount and at desired temperature and pressure to maintain operating temperature and pressures within the high pressure volume of the superheated vapor power generating device at optimum levels as determined by working fluid used and quality of available energy.

• FIG. 1 is a diagrammatic representation of a superheated vapor power actuated generating system utilizing the invention with an exhaust heat source, a burner as the source of superheat, and cooling fluid;
• FIG. 2 is a longitudinal cross-sectioned perspective view of the invention;
• FIG. 3 is a longitudinal cross-sectional view of a valve assembly;
• FIG. 4 is a transverse cross-sectional view of the valve assembly taken on the line 4-4 of FIG. 3;
• FIG. 5 is a transverse cross-sectional view of the valve assembly taken on the line 5-5 of FIG. 3;
• FIG. 6 is a partial longitudinal cross-sectioned perspective view of a second embodiment of the invention utilizing a reheat cycle;
• FIG. 7 is a diagrammatic representation of the second embodiment of the invention in a system utilizing a reheat cycle and an alternate heat source; and
• FIG. 8 is a diagrammatic representation of the second embodiment of the invention in a system utilizing the superheater as the reheat source and a second alternate heat source.

Referring to FIG. 1, a low grade heat source such as an exhaust stack 2 has placed within a heat absorption coil 4 of a closed loop heat transfer means containing a fluid such as water which absorbs a portion of the heat from the heat source when flowed through coil 4 then pumped through line 5 by pump 6 into the heat exchange coils 7 of a saturated vapor generating cell 10 of conventional means equipped with a pressure relief valve 12 and containing a quantity of liquefied working fluid 13 such as Freon which is heated sufficiently by regulating flow rates of pump 6 by conventional means to cause the liquefied working fluid to undergo a phase change to saturated vapor. The heat transfer fluid having given up its heat is recycled to heat source 2 through conduit 8. The saturated vapor of the working fluid flows through conduit 14 into the superheated vapor generating cell 16 equipped with a pressure relief valve 24 and which introduces additional heat supplied and controlled by conventional means such as burners 18, fueled by a fuel source and line 20, and regulated by conventional pressure and temperature controls. The working fluid passes through heating coils 22 picking up sufficient additional heat to become a superheated vapor and pass through throttling valve 26 through conduit 28 into high Pressure fitting 30 in the outer shell 32 of the superheated vapor actuated power generating device 32 equipped with a pressure relief valve 44 and rotational power output shaft 46. Exiting from both ends of the low pressure vessel 94 of the superheated vapor actuated power generating device are cooling fluid inlet lines 118 and discharge lines 120. Liquefied working fluid is discharged through pressure fittings 112 into discharge lines 114 into tee fitting 121 and then through conduit 122 into the liquid reservoir of the saturated vapor generating cell 10, completing the closed loop of the working fluid.

FIG. 2 illustrates the preferred embodiment of the superheated vapor actuated power generating device which comprises an inner cylindrical high pressure vessel formed by left and right walls 34 joined at 36 and sealed by conventional means 40 by seating in a notch 37 formed at the mating surfaces of the right and left sections of the outer shell 32 and mechahically compressed by a plurality of mechanical connections 38 around the exterior of the outer shell. The volume between the outer shell walls 32 and the high pressure vessel walls 34 is filled with a conventional structural and insulating material (42). Rotational output shaft 46 is journal at bearing 47 and connected to the yoke assembly 49 at the end of piston rod 48. Piston rod 50 is connected at the yoke assembly 49 by means of pin 52. High pressure piston 54 of bank A is connected to piston rod 48 and high pressure piston 54' of bank B is connected to piston rod 50 by means of pins 56. Except for the differences in the yoke connection ends of piston rods 48 and 50, the left bank A of the superheated vapor actuated power generating device and right bank B are mirror images of the other so the description of components apply to either bank. High pressure piston 54 is surrounded by rings 58 within cylinder sleeve 60. The volume 73 contiguous to the top face of high pressure piston 54 is either an isolated volume when communicating port 66 of electromagnetic valve 59 is in its central or closed position, in direct communication with the high pressure volume 35 by the radial alignment of communicating port 66 with the high pressure cylinder sleeve intake ports 65 and valve body ports 67, or in communication with high pressure cylinder discharge conduit 68 by the radial alignment of communicating port 66 with the high pressure cylinder discharge ports 62 and high pressure cylinder discharge conduits 68. By referring to FIG. 3 and 4 it can be seen that high pressure cylinder discharge conduits 68 are fed by high pressure cylinder discharge manifold 63 which is in direct communication with the high pressure cylinder volume 73 by a plurality of radial ports 62 when aligned with communicating ports 66. Referring back to FIG. 2, in order to minimize the volume 73 contiguous to the high pressure piston 54 when at top dead center of travel and allow communication with high pressure cylinder discharge conduits 68, the end wall of the high pressure cylinder is formed by the elongated cylindrical structure 74. Connecting rods 57 are attached to the top face of high pressure piston 54 and to the low pressure piston 76 with seals 75 and guides 77 surrounding the connecting rods 57.

Exhaust gases from high pressure cylinder volume 73 are evacuated into the varying low pressure cylinder volume 81 contiguous to the bottom face of low pressure piston 76 determined by travel of low pressure piston 76 and caused to swirl within the low pressure cylinder volume 81 by the concave configuration 80 on the bottom face of low pressure piston 76 and the complimentary concave configuration 82 at the end wall of low pressure cylinders 87. The volume 81 contiguous to the bottom face of low pressure piston 76 being increased at a greater rate than the decreasing volume 73 contiguous to the top face of high pressure piston 54 plus the volume of conduits 68 causes a lower pressure resulting in a rapid expansion of working fluid into low pressure cylinder volume 81 resulting in near total evacuation of working fluid from high pressure cylinder volume 73 and the impartation of work on the bottom face of low pressure piston 76 in the form of expansion of the vapor and kinetic energy of the working fluid molecules while the top face of low pressure piston 76 is exposed to the lowest system pressure that occurs within the working fluid system in low pressure vessel volume/condenser 86. Porting into the low pressure cylinder volumes 81 is performed by an electromagnetic valves 79 mechanically similar to electromagnetic valves 59. The volume 83 contiguous to the top face of low pressure piston 76 is directly communicated with low pressure vessel volume/condenser 86 through a plurality of ports 84 in structure 85 which provides structural support for low pressure cylinder sleeve 105 and cylinder sleeve 89 of injector piston 90 with a plurality of piston rings 91. Low pressure vessel wall 94 equipped with pressure relief valve 95 is mechanically attached by conventional means 96 and conventional sealing means 99 at a plurality of flanges to end wall 92 and high pressure vessel outer shell 32. Injector piston 90 is directly connected by axial connecting rod 57 to low pressure piston 76 and high pressure piston 54. As injector piston 90, low pressure piston 76, and high pressure piston 54 travel from top dead center to bottom dead center the vacuum caused by the increasing volume 93 causes check valve 92 to unseat and draw liquefied working fluid 103 through suction tube 100 and into injector volume 93. Upon injector piston 90 travel from bottom dead center to top dead center the increased pressure causes check valve 92 to seat and check valve 106 to unseat causing liquefied working fluid to be forced through pressure fitting 110 through the end wall of low pressure vessel 94 and secured by pressure fitting 112 and through working fluid discharge line 114. Working fluid exhausted into low pressure vessel volume/condenser 86 is cooled and liquefied by heat absorption through condenser tubes 88 by running a sufficient quantity of cooling fluid such as water through condenser tubes 88. Liquefaction of the working fluid decreases pressure to the lowest point in the closed working fluid loop allowing the greatest pressure differential to occur between the bottom face of high pressure piston 54 and the directly linked top face of low pressure piston 76 resulting in working forces applied parallel to the axis of piston movement.

FIG. 3 shows a double action electromagnetic valve assembly 59 which is mechanically similar to electromagnetic valve assembly 79 consisting of coils 70 and 70' encapsulated spring return assemblies 71 and slide valve bumpers 72. In the non-actuated position spring return assemblies 71 positions communicating ports 66 in their neutral or closed position. By activating coil 70 the slide body 102 moves to the right as illustrated in FIG. 3 which radially aligns communicating port 66 with cylinder discharge ports 62 with exhaust manifold 64 which in turn is connected to exhaust conduit 68 when the valve assembly is used in conjunction with high pressure cylinder 54 or to low pressure vessel volume/condenser 86 when used in conjunction with low pressure cylinder 105. Deactivation of coil 70 causes the slide body 102 to return to its closed position by forces exerted by spring return assemblies 71. During activation of coil 70' the slide body 102 moves to the left as illustrated in FIG. 3 and radially aligns communicating ports 66 with cylinder intake ports 65 and valve body discharge ports 67 which communicates with high pressure vessel volume 35 when used in conjunction with high pressure cylinder 54 or to high pressure discharge conduit 68 when used in conjunction with low pressure cylinder 105.

FIGS. 6 and 7 depict an alternate embodiment of the invention wherein manifold 136 collects exhaust from high pressure cylinder 60 through manifold 136 and transfers by conduit 138through the end wall of low pressure vessel 94 through pressure fitting 140 through conduit 144 to reheater 146 containing heat element 148 and returned to the low pressure vessel end wall 94 through pressure fitting 152 through conduit 154 into collection manifold 156 which distributes reheated vapor to the intake port of low pressure cylinder 105. Also shown is alternate heat absorption means 155 being air-water heat absorption coil.

FIG. 8shows a modification wherein conduit 144 is routed through superheat vapor generating cell 16 and heat transfer tubes 160 returning to the end wall of low pressure vessel 94 through conduit 150. Also shown is an alternate heat source, which is a flow through hot water conduit 162.

It will be appreciated that if there is only one superheated vapor power generating device as depicted by the left bank A in Fig. 2A then power will be delivered to the working shaft 46 during a 180° degree period of rotation; but ifthe right bank B in Fig. 2B is also coupled to the working shaft 46 then power will be delivered to the working shaft during a 360° degree period of rotation.