Dual type multiple stage, hydraulic turbine power generator including reaction type turbine with adjustable blades

[0002] Hydraulic Turbine Power Generator incorporating a plurality of Reaction type turbine stages including a turbine stage with adjustable blades for maximizing turbine efficiency and controlling the output electrical frequency of the power generator.

[0003] This invention is an improvement of the Hydraulic Turbine Power Generator that is the subject of the Weisser U.S. Pat. No. 5,659,205, assigned to the same assignee as the present invention. The hydraulic turbine of U.S. Pat. No. 5,659,205 is operable with a hydraulic fluid source that has a variable flow rate and a high pressure and is converted by the turbine structure to a relatively high fluid velocity. The turbine runner blades disclosed in the prior patent are fixed, axial runner blades so that the rotary speeds imparted to the single shaft mounting the hydraulic turbine and power generator is operative at variable, rotary speeds. The power generator is provided with a variable frequency exciting current source controlling the synchronous speed of the generator to be changed by connecting the power generator stator windings to be energized by the variable frequency exciting current source thereby providing output power at a preselected, constant frequency to compensate for the variable output frequencies generated in response to the variable shaft speeds of the single shaft mounting the power generator. Experience with the patented hydraulic power generator has resulted in that the need for the variable speed, constant frequency controller, identified in the above identified prior patent as element IS, has produced problems due to the operational problems encountered with the commercially available controller IS. This problem has resulted in the desirability of providing a hydraulic turbine power generator and more particularly submersible hydraulic turbine power generator operative with preselected hydraulic fluids that eliminate the need for the use of the variable speed, constant frequency controller to thereby provide a power generator free of the frequency controller problems.

[0004] The present invention provides an improved hydraulic turbine power generator arranged on a single shaft that is operable as a submersible hydraulic turbine electrical power generator that is operative at a constant speed and provides output power at a constant frequency without the need for a variable speed, constant frequency controller for the power generated resulting in a relatively trouble free hydraulic turbine electrical power generator.

[0005] The basic concept of the present invention is the incorporation of a plurality of reaction type turbine stages arranged in serial fashion on the single shaft for the hydraulic turbine power generator with the output stage of the hydraulic turbine being responsive to the fluid flow discharged from the input turbine stage or stages and being characterized as having a plurality of adjustable blades that permit the pitch of the blades to be adjusted for varying the fluid flow through the output stage to achieve a substantially constant speed for the single shaft mounting the hydraulic turbine and electrical power generator and maximizing the efficiency of the turbine. The input turbine can be a Francis type turbine stage of single or a plurality of stages while the output turbine stage can be a Kaplan type turbine stage.

[0006] In accordance with the present invention the adjustable pitch blades can be rotated to any desired position by either statically moving the blades when the turbine is inoperative or by dynamically adjusting the turbine blades when the turbine is operative. In the disclosed static adjustment of the adjustable turbine vanes, the hydraulic turbine mounts a supporting structure adjacent the fluid discharge end thereof for mounting an electrical motorized device operable to extend a keyed blade for adjustment purposes. A gear drive system is imbedded into Kaplan style turbine runner for controlling the pitch of the runner blades of the Kaplan style turbine runner so that the efficiency of the turbine can be fine tuned. The keyed blade is adapted to fit into a positioning shaft controlling the movements of the gear drive system. This static adjustment is accomplished while the turbine is inoperable and when the adjustment is complete, the keyed blade is retracted and the turbine is in condition to be operated at the adjusted pitch for the runner blades.

[0007] The dynamic adjustment of the Kaplan style runner blades is accomplished while the turbine is operative by the use of a gear drive system imbedded into the Kaplan style runners also controlled by a positioning shaft. In this case, a low voltage stepper motor incrementally controls the positioning shaft and thereby the pitch of the runner blades with the turbine in operation. The stepper motor is powered from the turbine electrical power generator by tapping off the rotor end rings and with the stepper motor being responsive to digital positioning commands. The power flow in the rotor is low voltage and low frequency of approximately 20 Hertz while the digital signals are transmitted to the stepping motor through the turbine electrical power generator rotor by means of the magnetic field across the gap between the rotor and stator of the power generator.

[0008] The use of the turbine with adjustable blades is also advantageous when the source of hydraulic fluid is in two phases, namely a liquid and gas/vapor mixture. In this embodiment, a turbine expander is used for permitting pressure reduction into the vapor phase but takes advantage of the buoyant and convective forces of released gas or vapor by routing the fluid in a vertical direction such that the fluid is aided by these forces as contrasted with the reverse or downward, conventional flow. The reverse fluid flow mixture through the turbine causes the rise of the bubbles of released gas or vaporized liquid aids the primary fluid flow. The entire hydraulic turbine electrical power generator is arranged in a closed container with suitable fluid inlet and a separate fluid outlet and gas/vapor outlet so as to function as a separator of the gas/vapor from the liquid.

[0009] These and other features of the present invention may be more fully appreciated when considered in the light of the following specification and drawings, in which:

[0010] FIG. 1 is a cross-sectional view of a submerged hydraulic turbine electrical power generator operative at a preselected speed and including a static means for adjusting the turbine blades pitch to achieve the preselected speed and embodying the present invention;

[0011] FIG. 2 is a partial cross-sectional view of the Kaplan style runner assembly of FIG. 1 illustrating the gear drive system for adjusting the turbine blades pitch;

[0012] FIG. 3 is a cross-sectional view of a submerged hydraulic turbine electrical power generator operative at a preselected speed and including dynamic means for adjusting the turbine blade pitch to achieve the preselected speed and embodying the present invention;

[0013] FIG. 4 is a partial, cross-sectional view of the Kaplan style runner assembly of FIG. 3 illustrating the gear drive system controlled by a stepper motor powered from the turbine power generator;

[0014] FIG. 5 is a diagrammatic, detached view of the common turbine power generator shaft of FIG. 3 illustrating the energization and control of the stepper motor for adjusting the pitch of the turbine blades;

[0015] FIG. 6 is a partial, cross-sectional view illustrating the thrust equalizing mechanism having its variable orifice open and illustrating the hydraulic fluid flow through the turbine runner, thrust equalizing mechanism and ball bearing;

[0016] FIGS. 7-9 are partial, cross-sectional views of the turbine power generator shaft of FIG. 3 and illustrating the energization arrangement of the stepper motor from the electrical power generator;

[0017] FIG. 10 is a cross-sectional view of the turbine expander of FIGS. 1 and 3 operative from a source of two phase hydraulic fluid arranged in a substantially closed discharge container with the fluid flow in a reverse flow arrangement from FIGS. 1 and 3 and functioning as a two phase separator of the liquid stream from the gas/vapor portion of the mixture; and

[0018] FIG. 11 is a cross-sectional view of a turbine expander of FIGS. 1 and 3 for processing two phase fluids without separating the liquids and gas/vapors and embodying the present invention.

[0019] Now referring to the drawings, the hydraulic turbine electrical power generator of the present invention operative at a preselected single speed and thereby a single electrical frequency for the generated electrical power will be described in detail. The hydraulic turbine electrical power generator HTPG is illustrated in the drawings and will be described for use as a submerged hydraulic turbine power generator HTPG to be operative as a submerged hydraulic turbine generator HT to be operative in response to cryogenic, liquefied gases coupled to the hydraulic turbine. The hydraulic turbine HT and the electrical power generator PG are both mounted on a single shaft SS. For the purposes of the present invention, the terms “hydraulic fluids” or “hydraulic fluid flow” is an operative hydraulic fluid for operating the hydraulic turbine HT and cooling the electrical power generator PG are electrically, non-conductive fluids, including cryogenic liquefied gases, such as liquefied natural gases, liquefied methane gas, liquefied ethylene gas, liquefied petroleum gas, and similar liquefied hydrocarbons. The usual source of hydraulic fluids provides the fluid at a varying or constant pressure and velocity such as may be obtained from wells, etc.

[0020] The hydraulic turbine HT and the electrical power generator PG are mounted on a single shaft SS to be rotatable in unison therewith upon the application of a preselected hydraulic fluid flow to the hydraulic turbine HT for causing the shaft to be rotated in response to the hydraulic pressure and velocity of the selected hydraulic fluid applied.

[0021] As contrasted with the hydraulic turbine power generator disclosed in the aforementioned U.S. Pat. No. 5,659,205, the hydraulic turbine HT of the present invention is a multiple stage reaction turbine of the type disclosed in said '205 patent and as disclosed in the Proceedings of the American Power Conference, Volume 60-1 sponsored by the Illinois Institute of Technology in Chicago in 1998, pages 200-204. The thrust equalizing mechanism, TEM, disclosed in both aforementioned patent and publication are incorporated into the hydraulic turbine power generator HTPG of the present invention. The operation of the thrust equalization mechanism TEM described in the '205 patent and the Proceedings of the American Power Conference referenced hereinabove are incorporated herein by reference. To the same end, the detailed arrangement of the thrust equalization mechanism TEM for the present invention is best appreciated from viewing FIG. 6. The mechanism TEM is operative with the lower bearing RB for the shaft SS, best illustrated in FIG. 6, to be operative with the turbine runner R. The shaft SS is also provided with a second ball bearing, or the top shaft radial bearing RBT which has a portion of a reduced diameter from the adjacent portion of the shaft SS. This arrangement of the components is considered to be the “shaft assembly” since they are rotated at the speed of the shaft SS and axially movable with the bidirectional movements imparted to the shaft SS and the ball bearing RB in accordance with the operation of the thrust equalizing mechanism TEM.

[0022] The above described shaft assembly is housed within a common housing CH for enclosing and isolating the components of the “shaft assembly” along with the lower portion of the shaft SS except for the turbine runner R and the remaining portion of the shaft SS, all as illustrated in FIG. 1. The common housing CH is submerged in a containment vessel CV that encloses the entire hydraulic turbine electrical power generator HTPG in a spaced relationship with the common housing CH. The containment vessel CV is provided with a fluid inlet for receiving the hydraulic fluid from the fluid source illustrated as a block coupled to the vessel CV. The hydraulic fluid is discharged from the lower end of the shaft SS, as illustrated in FIG. 1. The space between the housing CH and the vessel CV is provided with nozzle means NM, see FIG. 6, opposite the housed turbine stages for serially impinging on the turbine runners. The turbine stages illustrated in FIG. 1 consists of three stages of a Francis type turbine stages identified as the stages 4, 5, and 6, with the later stage incorporating the thrust equalizing mechanism TEM therein. The last Francis type turbine stage discharges into the Kaplan type runner assembly identified as the stage 1 and housed within the draft tube 2. The draft tube 2 is utilized to aid the turbines in the recovery of fluid pressure by slowing down the flow and increasing the back pressure at the Kaplan runner assembly. As in the prior art, the single shaft SS mounts the electrical power generator PG in the form of an induction generator. The induction generator PG illustrated in FIG. 1 has its rotor 9 mounted to the shaft SS to be rotatable therewith at the speed imparted to the shaft by the turbine stages. The generator stator is identified as the element 7 and is within the concentric housing 8. The electrical power generated by the element PG, is available at the power cables 12. The Kaplan runner assembly constructed with adjustable blades 16 for controlling the speed of the shaft SS is best appreciated from viewing FIG. 2. The adjustable runner blades 16 for the Kaplan turbine runner is provided with a gear drive assembly 17 comprising bevel gears fixed to the runner by mechanical means 15. The main bevel gear drives four minor gears attached to each of the turbine blades. The rotation of the main gear rotates the minor gears thereby adjusting the pitch of the runner blades. A runner blade positioning shaft 18 is used for rotating the gear drive assembly 17. The end of the positioning shaft 18 is keyed to accept an adjusting blade for adjusting the position of the turbine blades.

[0023] As is illustrated in FIG. 1 a runner blade adjusting means 14 that has a motor actuated blade that is operable to extend and retract a keyed blade into the exposed end of the adjustment shaft 18. For this purpose the runner blade adjusting means 14 is supported by a mounting bracket 13 secured to the end of the draft tube 2, as illustrated. The motor for the adjusting means 14 is powered by means of the power and control cable 10 that power adjusting means 14 and control the commands for positioning the keyed blade into and out of engagement with the positioning shaft 18.

[0024] The ability to adjust the pitch of the Kaplan turbine blades allows the fluid flow through the turbine to be controlled in a manner similar to a control valve so that rotary speed of the shaft SS can be controlled and maximize the efficiency of the combination of the different types of turbines.

[0025] The embodiment of FIG. 3 as to the hydraulic turbine power generator HTPG is the same as that illustrated for FIG. 1 except that the gear drive assembly 17 is dynamically adjusted, as best seen in FIG. 4. In FIG. 4, the adjustable blades for the Kaplan runner assembly are identified by the number 42 in FIG. 4 and the gear drive assembly 43 of FIG. 4 is the same as the gear drive assembly 17 of FIG. 2. In this embodiment (FIG. 4) the gear drive assembly 43 is controlled by means of a conventional stepping motor 45 having a positioning shaft 15S coupled to the gear drive assembly 43 for varying the pitch of the adjustable blades 42. Stepping motors are well known in the prior art and one such motor is disclosed in U.S. Pat. No. 3,660,746. The stepper motor 45 is energized from the induction generator PG coupled by the lead wires 47, as illustrated in the drawings, FIGS. 4-9. The lead wires 47 are arranged in a central aperture provided in the shaft SS. The power leads 48 are tapped off opposite sides of the rotor 9 end rings as shown in FIG. 5. The leads 47 transmit both the electrical power for the stepping motor 45 and the digital commands for incrementally stepping the positioning shaft 15S to achieve the desired pitch for the blades 42 and thereby the desired shaft speed and electrical output frequency. The gear mounts 46 are the mechanical means for fixing the gears to the runner blades 42. The end cap 44 illustrated in FIG. 4 is a detachable cap that bolts into place and secures the gears and the runner blades 42 to the shaft SS.

[0026] It should now be evident that the hydraulic turbine power generator HTPG needs to be operative in order to vary the pitch of the Kaplan runner assembly as the pitch is controlled by the stepping motor 45 and is energized from the induction generator PG.

[0027] It should be recognized that an important feature of the disclosed embodiments is the selection of the type of hydraulic turbines to be utilized for the purposes of the invention. The hydraulic turbine means comprise at least a plurality of reaction type turbine stages arranged to be in combination, to be rotatably responsive to a fluid flow coupled to the turbine whereby the rotary speed of the common shaft can be controlled to achieve a preselected shaft speed. The plurality of reaction type turbine stages are preselected to have reverse performance characteristics. One of the turbine stages having radial turbine runner means to be rotatably responsive to the hydraulic fluid coupled thereto for rotating the common shaft. One such turbine is a Francis type turbine of a single or multiple stages. The second reaction type turbine has an axial turbine runner means with adjustable blades for permitting the pitch of the blades to be adjusted for controlling the effective operative fluid head for the turbine means to cause the shaft to rotate at a preselected speed and thereby a preselected electrical frequency for the generated power. The Kaplan type turbine means is suitable for this purpose.

[0028] The above embodiments are operative with the above described liquefied gases without any gases or vapors therein or single phase turbine expanders. The embodiment of FIG. 10 utilizes the hydraulic turbine power generators HTPG for use with hydraulic fluid sources of two phases, namely a liquid and a gas/vapor phase in a mixture or in combination. Two phase turbine expanders used in cryogenic gas processing have been disclosed in the prior art. One such publication is the Dr. Hans Kimmel et al publication presented at AlCHE 1999 Spring National Meeting of the American Institute of Chemical Engineers on Mar. 17, 1999, paper number 126e, 17 pages. In this disclosure of a two phase turbine expanders were not found to be satisfactory since it has only utilized radial turbine runners. It is believed the embodiment of FIG. 10 is a superior two phase turbine expander in Cryogenic Gas Processing not disclosed in the known prior art. It will be appreciated that the hydraulic turbine power generator HTPG illustrated in FIG. 10 is the same as illustrated in FIGS. 1 and 3 without the detailed illustration of the means for adjusting the blades of the Kaplan runner assemblies. These features will be included in any practical device but are omitted for simplifying the understanding of the present invention. In examining FIG. 10 it will be noted that contrary to the fluid flow in the previous embodiments wherein the fluid flow is in a downward direction the primary fluid flow is reversed or in an upward direction as illustrated. This upward flow direction, the rise of the bubbles of released gas or vaporized liquid aids the primary fluid flow. For the purpose of processing a two phase fluid source the entire mechanism HTPG is enclosed in a substantially closed discharge container means or a discharge pressure vessel CC. The container means CC has a fluid inlet for receiving the fluid from the source of two phase hydraulic fluid illustrated in block form at the bottom of FIG. 10, as illustrated therein. The container means CC has a vapor outlet conduit VO at the opposite end of the container means CC or at the top thereof in FIG. 10. Intermediate the top and bottom ends of the container means CC there is provided a liquid outlet conduit LO permitting the liquid phase of the hydraulic fluid to be expelled. It will be appreciated by those skilled in the art, that the high fluid pressure processed by the multi stage turbine experiences a substantial reduction in pressure in the driving of the turbine stages within the hydraulic turbine stages. The vessel CC is illustrated in FIG. 10 is supported on the support bracket SB.

[0029] During the operation of the turbine stages the gases or vapors traverse the various stages so that the liquid gas/vapor mixture exits the Kaplan runner assembly. Due to the orientation of the apparatus HTPG the gas bubbles being of light weight move out of container CC through the vapor outlet VO. The hydraulic fluid being heavier in weight in exiting the Kaplan runner assembly will drop downwardly, as illustrated in the drawing and exit the container CC at the liquid outlet LO. In this fashion the container CC functions as a two phase separator, separating the liquid from the gas/vapor.

[0030] The preferred embodiment of the two phase turbine described in conjunction with FIG. 10 is illustrated in FIG. 11. In this embodiment, the container CC is not utilized and the liquid and gas/vapor mixture is not separated. The other differences in this embodiment is that the source of hydraulic fluid coupled to the turbine means is not a two phase source but merely hydraulic fluid under pressure. The fluid inlet and fluid outlet are in line so that any released secondary gas or vapors are processed through the turbine stages and exit as a mixture from the fluid outlet.

[0031] Although the hydraulic turbine power generator HTPG described in FIGS. 10 and 11 are described in conjunction with the above described embodiment of the present invention, one of the important features of this combination of elements is the ability to adjust the pitch of the Kaplan runner assemblies that is particularly useful for these types of two phase applications. The Francis type turbine can be omitted and the variable speed hydraulic turbine can be used as a replacement along with the adjustable blade Kaplan runner assemblies. The variable speed hydraulic turbine can be the turbine disclosed in the U.S. Pat. No. 5,659,205 of Weisser. In this combination, the adjustments are both to the rotational speed and the adjustable blades. This combination has a very broad and flexible operational field and is particularly useful for the two phase turbine flow embodiment.