Title of Invention	"IMPROVED VERTICAL AXIS WIND ELECTRICITY GENERATOR-CUM-WIND WATER PUMP"
Abstract	An improved vertical axis wind electricity generator which comprises a space frame, a plurality of guy-wires, a pair of vertical axis rotor assemblies, said space frame accommodates a plurality of vertical members supported by said guy-wires and cross members, said space frame being attached to vertical partitions at four corners thereof, said vertical axis rotor assemblies being held in position by means of radial support and thrust bearing at its top, each of said rotor assembly comprises two or more rotors in said rotor assemblies, said rotors located in the upper and lower portions and connected by cop-cone arrangement so that power available from wind in upper rotors is transmitted downwards and total power from wind is available at the bottom of the lowermost rotor wherein each rotor comprises a pair of blades of thin sheets curved across the vertical plane and assembled to have the concave side of each blade facing each other, each of said blade being held in position on a vertical girder structure and further each said blade being off-set from the center-line of the girder structure so that preferably 2/3m of the concave face of said blade remains uncovered by the said other blade.

Title of Invention

"IMPROVED VERTICAL AXIS WIND ELECTRICITY GENERATOR-CUM-WIND WATER PUMP"

Abstract

An improved vertical axis wind electricity generator which comprises a space frame, a plurality of guy-wires, a pair of vertical axis rotor assemblies, said space frame accommodates a plurality of vertical members supported by said guy-wires and cross members, said space frame being attached to vertical partitions at four corners thereof, said vertical axis rotor assemblies being held in position by means of radial support and thrust bearing at its top, each of said rotor assembly comprises two or more rotors in said rotor assemblies, said rotors located in the upper and lower portions and connected by cop-cone arrangement so that power available from wind in upper rotors is transmitted downwards and total power from wind is available at the bottom of the lowermost rotor wherein each rotor comprises a pair of blades of thin sheets curved across the vertical plane and assembled to have the concave side of each blade facing each other, each of said blade being held in position on a vertical girder structure and further each said blade being off-set from the center-line of the girder structure so that preferably 2/3m of the concave face of said blade remains uncovered by the said other blade.

Full Text	This invention relates to an improved vertical axis wind electricity generator. Wind mills are known for hundreds of years, including vertical axis ones. The latest wind mills used for power generation comprise of aerodynamically designed, microprocessor controlled, rpm regulated blades, providing grid-quality electrical power. But these machines have an inherent drawback as they start operation from a wind speed around 5 meters/sec. Areas with prevalent wind speed of 5 meter/sec, and above are quite restricted. In India only a few districts of Andhra Pradesh, Gujarat and Tamil Nadu are having wind speed where modern wind electricity generators are viable due to above restriction. Disadvantage experienced in the vertical axis machines of the prior art is the very low revolution rate of the blades due to various factors including the design thereof. A still further disadvantage of known machine is the varying torque at different angular positions of the rotor within the same revolution. In the prior art no vertical axis wind-electricity generators have been designed for large scale power generation. 2. An object of the present invention is to mitigate the above drawback of the prior art. A further object of the present invention is to reduce the cost of transforming kinetic energy of wind into mechanical energy. A still another object of the present invention is to enhance the area of application of wind electricity generator particularly in a country like India where there is a tremendous shortage of electricity in rural areas. The improved vertical axis wind electricity generator of the present invention has the following new features. 1. A complete new machine have been worked out with (1) vertical axis blades to develop mechanical energy from wind for driving pumps or electrical machines. The design provides (2) an arrangement to couple a number of parallely running vertical wind turbine to drive (3) centrally large electrical machines or water pumps. 2. The machine excels in the quality that it operates from a wind speed of about 2 meter/sec. Besides, it does not need sophisticated technology such as aerodynamically designed blades. As such, its per square meter cost is expected to be much lower than that of the conventional machines. Via bility in low wind makes the area of application much more wide and manifold compared to that of the know machines. 3. 3. The combination of finish and geometry of the convex and concave surface of the curved bLades have been carefully designed to have efficiency in transformation of wind kinetic energy by the vertical axis blades to much better result than that of the known machines. 4. The two principal difficulties of the vertical axis wind turbines known in- the literature, i.e. their very Low revolution rate and varying torque at different angular positions of the rotor within the same revolution are removed in the machine design being disclosed. According to this invention there is provided an improved vertical axis wind eLectricity generator comprising: a space frame, a plurality of guy-wires, a pair of vertical, axis rotor assemblies, said space frame accommodates a plurality of verticaL members supported by said guy-wires and cross members, said space frame being attached to vertical partitions at four corners thereof, said vertical axis rotor assemblies being held in position by means of radiaL support and thrust bearing at its top, each of said rotor assembly comprises two or more rotors in said rotor assemblies, said rotors located in the upper and lower portions and connected by cup-cone arrangement so that power available from wind in upper rotors is transmitted downwards and total power from wind is available at the bottom of the lowermost rotor, 4. wherein each rotor comprises a pair of blades of thin sheets curved across the vertical plane and assembled to have the concave side of each blade facing each other, each of said blade being held in position on a vertical girder structure and further each said blade being off-set from the center line of the girder structure so that preferably 2/3™ of the concave face of said blade remains uncovered by the said other blade. - 5 - The present invention will now be described in detail with reference to the accompanying drawings, wherein Figure 1 shows a section of the vertical axis wind electricaly generator of the present invention ; Figure 2 shows sectional plan view of the rotor blades of the electricity generator; Figure 3 shows the schematic diagram of plan view of the blades of rotor assemblies; Figure 4 shows one of the lower most girder structure with supports; and Figure 5 shows the coupling of electrical machines/ water pump with the main pulley of the generator. With reference to the above drawings the improved vertical axis wind electricity generator and/or wind water pump (abbreviated hereinafter as IWEG ) consists of (1) a space frame (Figure 1) with vertical members (10,12,14) supported by guy-wires (15,16,17,18) and cross members (20, 22,24) holding inside it two vertical axis rotor-assemblies (30, 32). Vertical partitions (40, 42) are to be attached to the four corners of the space frame for more power output during low wind period, for concentrating the wind-flow to increase actual speed of wind while reaching the rotor-assemblies. 6 The rotor assemblies are held in position by means of radial supports (50,52) and thrust bearing (55) at top. Each rotor-assembly can be of height needed for the power generating capacity as required by the customer, larger height for larger capacity, but each such rotor-assembly consists of two or more rotors (60, 62,64) comprising a rotor-assembly (30) of smaller height. These smaller units are of said size and of optimum mechanical strength to enable them to withstand very high wind speeds . -Whatever, might ^ be the number of rotors in a rotor-assembly, the upper ones will bp connected to the lower ones by cup-cone arrangement (65"* so that power available from wind in upper rotors is transmitted downwards and total power from wind^ is available at the bottom of the lowermost rotor, even if one rotor is -nob* perfectly aligned to the others. Each rotor (Figure 2) consists of pair of two blades (70, 72) made of thin sheets, curved across the vertical plane.; assembled such that the concave side of each blade faces each other, and they are held in position on a vertical girder-structure (75) and each blade is offset from the center-line of the girder-structure so that preferably about 2/3rd of the concave face (.80) (chord-length) of the blade remains uncovered (82) by the other blade. The four ends (90,92,94,96) of the two curved blades are held in a same vertical plane (100) and this plane will be referred to in this specification as 'Principal Plane1 of the rotor in subsequent paragraphs. The radius of curvature (101) of the end of the blade away from the center-line is much smaller than (105) of the end nearer to the centre-line. The outer convex surface of the curved blades will be as smooth as possible to allow undisturbed flow of wind along them. The concave surface of the curved blades will be with horizontal and vertical strengthening ribs (106) which will provide mechanical strength to the thin curved blades to withstand wind thrust, and also these will disallow smooth flow of wind tangential ly t.c the inner blade surface and make the wind flow turbulant.. Now, the curvature of the blades in one rotor-assembly will be arranged in opposite direction f(T2 5.,f1 30) of that of the other rotor-assembly (Figure 3). The principal plane of each rotor of a rotor-assembly is maintained at an angular displacement from that of all other rotors inside the space frame, placed above, below or at rive s i"de D'f it (all the principal planes 110, 112, 114, 120, 121 and 124 are at an angle with each other). S The girder-structure as illustrated in Figure 4, mentioned in the previous paragraph (75) is in fact replacement of a shaft for reducing the weight of the rotating mass, and is supposed to have at its top and bottom ends two round shafts (140, 145). In case wind-speed and resultant torque requires, the girder-structure will be replaced by a pipe. The upper end shaft (140) is held in position by an anti-friction bearing in a bearing-housing (150) supported from space frame by supporting connectors (50,52). Also this shaft (140) receive a cone (65) at its top end to hold in position the lower end of the shaft (145) of the immediate upper rotor, to which the cone is rigidly fixed. There is a cross pin (170) fixed at the upper end of the shaft (140) to receive rotational torque from the cone. The lower end shaft (145) of the girder-structure is to be supported on a vertical shaft (175) , (hereinafter called ."Stake Shaft" by a similar cone arrangement, to which the total rotating force is transmitted. The Stake Shaft (175) is held steadily by radial and thrust antifriction on bearings placed in a bearing-housing (180). This housing is rigidly grouted to the top of a concrete/ brick column (190) standing on ground. So, the assembly composed of 2 shafts and girder-structure (140, 75 and 145) can freely rotate along with the rotor blades mounted on it, between top and bottom antifriction bearings, along vertical axis, fixed in position in the space frame. jr. : 9 The stake shaft (175) is to have a bevel gear (201) mounted on it. This bevel gear rests on a thrust-plate (205) and will be receiving rotational torque from the stake shaft (175) through a friction clutch (206). The same arrangement is to be repeated for the lower end of the girder-structure of the lowest rotor of the other rotor-assembly (Figure 4 shows for simplicity only the bevel gear of the other rotor-assembly). The bevel gears of both the rotor-assemblies are to be in same horizontal plane, and these two bevel gears will drive a common horizontal shaft (210) (hereinafter called "Main Shart") through two bevel pinions (211, 213) from two ends of the shaft. The main shaft (210) is held in position between anti-friction bearings in bearing housings (220). There is a large diameter belt pulley (225) rigidly mounted on the main shaft (210). This pulley will be hereinafter called "Main pulley". The rotor-assembly rpm will vary directly with the wind speed. The rpm of the main pulley will be varying directly with the rpm of the rotor-assemblies, because of direct gearing. The coupling of electrical machines/water pumps with main pulley is depicted in Figure 5. The main pulley (225) drives via a belt pulley (230.) of small diameter rigidly mounted on a shaft (232) (called "Counter Shaft.). lo The Counter Shaft (232) supported in position by bearings (234, 236) is to have 3 large beLt pulleys (240, 243, 245) on it, driving 3 electrical machines (or water pumps) (241, 242, 24 4) respectively. These three large pulleys (240, 243, 245) are to receiverotating power from Counter Shaft via friction clutches (250, 251, 252). The clutches will engage the large (240), medium (243) or small (245) puLley respectively during low, medium or high wind speed. In turn, 3 electrical machines/water pumps (241 , 242, 244 will be driven respectively during low, medium or high wind. These machines are of smalI, medium and high capacity, operating during low, medium and high wind speed respectively. More pulleys/clutches/electrical machines wiLl be put to parallel operation in areas where the operating range of wind speed will be very wide. The selective engagement of the clutches wiII be actuated by a speed sensor, sensing rpm of any one of the rotor-assemblies. The speed sensor will actuate the clutch (206) to disenage the bevel gears (201 ) from the rotor-assemblies during very high winds to save the equipments from damage due to over speed. Each of the electrical machines experiences a speed variations, though the range of variation is much less than the total range of wind speed variation. Output voltage of the electrical machines is regulated by field-current II control (not shown), to provide constant voltage variabLe amperes direct current output (as in automobile electrical machines). The machines running paraLlel wil I deliver the power to a common busbar or a storage battery. In case water pumps are driven, the water will1, be pumped up to the overhead storage tank, placed on top of Space Frame either to be used for driving water wheels/water turbines, to generator electricity in turn, or for any other puprose desired by the customer. For large power requirements, if the required height of the space frame a~pp'eaxs unsafe and costly for the local high wind conditions, a row of IWEG may be constructed but excluding the counter shaft, the speed sensor and the electrical machines. A common counter shaft will be constructed to be driven by all main pulleys from the different IWEG's, by belts covered for protection from weather and the single counter shaft is extended to reach all the main pulleys, which will receive power from alL the IWEG's delivering power to a single set of electrical machines or pumps, located in a power-house. A single speed sensor, getting speed signal from any one of the rotor-assemblies, wi II control all the clutches in the group of IWEG's. The row of IWEG will be constructed 'in a direction across the direction of maximum wind flow duration. The rotor-assemblies of the machine is exposed to the atmosphere along with the upper part of the space structure. The bevel gears, the friction c lutches, the \2- pulleys with the electrical machines, the control gears and the busbar with electrical switches etc are located in a covered area or room, preferably built with bricks between the vertical members of the space frame and a sloping roof below the lowest end of the rotor-assemblies. Wind from any direction causes one of the rotor-assemblies to rotate in clockwise direction and the other in anti-clockwise direction (Figure 3). The arrangement of the bevel gears cause the main shaft to be driven in one direction only by both of the rotor-assemblies. The rotation is caused by kinetic energy of the wind transformed to mechanical energy, partly by causing thrust drag force in the concave side of the blades, and force partly caused by the lift/created by the tangential attack of the flowing wind at a low angle on the convex (smoother) surface of the curved blades. The generation of lift component in the concave surface is negated by the presence of ribs which deters smooth tangential flow of wind along the concave side. The arrangement of belt pulleys have been planned in such a manner that the high-torque low rpm rotating force from the rotor-assemblies is transformed to a higher rpm suitable to operate electrical machines or pumps. As has been already explained, two or more electrical machines have been connected to operate parallel, but one only at a time, with a capacity matching to the power available from wind at the particular speed. This matching of the input power and output power increases system efficiency. j. \$ The mutual angular displacement position of different rotor blades (Figure 3) in the rotor assemblies will result in more uniform torque within a revolution of a rotor-assembly. The cone arrangement (Figure 5) at the lower end of rotors will accommodate mutual misalignment between the axis of rotation of the rotors of same rotor-assembly because of deflection due to wind thrust, by providing the required flexibility in a simple manner. The electrical machines may be replaced by water pumps. A combination of electrical machines and water pumps may also be possible. In that case, the wind energy will directly be used to pump water. The pumped water may either be used directLy for,, different purposes or may be stored in a tank at the top of the space frame for subsequently driving a water wheel or a water turbine for producing electrical power, during low winds, to make up the short supply for electricity from the wind force directly. It will be apprecated by a person skilled in the art that obvious alterations and/or modifications are possible to be included in the vertical axis wind electricity generator of the invention and therefore the above description is not exhaustive and will not unnecessarily limit the ,s.cape of this invention. WE CLAIM: 1. An improved vertical axis wind electricity generator comprising - a space frame (1), a plurality of guy-wires (15, 16, 17, 18), a pair of vertical axis rotor assemblies (30, 32), said space frame accommodates a plurality of vertical members (10, 12, 14) supported by said guy-wires and cross members (20, 22, 24), said space frame being attached to vertical partitions (40, 42) at four corners thereof, said vertical axis rotor assemblies being held in position by means of radial support (50, 52) and thrust bearing (55) at its top, each of said rotor assembly comprises two or more rotors (60, 62, 64) in said rotor assemblies, said rotors located in the upper and lower portions and connected by(§ 15 2. An improved vertical axis wind electricity generator as claimed in Claim 1 wherein four ends (90, 92, 94, 96) of said two concave plates are held in principal plane. 3. An improved vertical axis wind electricity generator as claimed in any of Claims 1 or 2 wherein the radius of curvature (101) oftheendof said blade which is positioned away from the center line is much smaller than the radius of curvature (105) of the blade located near the center-line. 4. An improved vertical axis wind electricity generator as claimed in Claim 3 wherein the outer convex surface of the curved blade is smooth and the inner concave surface of said curved blade is provided with horizontal and vertical strengthening ribs (106). 5. An improved vertical axis wind electricity generator as claimed in Claim 4 wherein the curvature of blades in one rotor assembly is arranged in opposite direction (125, 130) to the other. 6. An improved vertical axis wind electricity generator as claimed in any of the preceding claims wherein the principal plane from said rotor assembly is maintained at an angular displacement of that of all other rotors located inside the space frame. 16 7. An improved vertical axis wind electricity generator as claimed in Claim 1 wherein said girder structure is replaced by a pipe, said girder structure being provided at the top and bottom ends two round shafts (140, 145), said upper end shaft is held in position by an anti-friction bearing placed in a bearing housing (150) supported from space frame by supporting connectors (50, 52), said shaft (140) is fitted to a cone (65) at its top end to hold in position the lower end of the shaft (145) of the immediate upper end rotor in which said cone is rigidly fixed, a cross pin (170) is fixed at the upper end of said shaft (140) to receive rotational torque from said cone, the lower end of said shaft (145) of the lowermost girder structure is supported on a vertical shaft (175) by another cone arrangement to which the total rotating force is transmitted. 8. An improved vertical axis wind electricity generator as claimed in any of the preceding claims wherein said vertical shaft (175) is provded with a bevel gear (201) mounted on it and said bevel gear is rested on a thrust-plate (205) to receive rotational torque from said vertical shaft through a friction clutch (206). 17 9. An improved vertical axis wind electricity generator as claimed in any of Claims 1, 7 or 8 which optionally comprises at the lower end of the girder structure of the lowest rotor of the other rotor assembly a bevel gear which is connected to the other bevel gear of the said other rotor assembly through a common horizontal shaft (210). 10. An improved vertical axis wind electricity generator as claimed in Claim 9 wherein said common shaft connecting the bevel gears of rotor assemblies is held through two bevel pinions (211,213) positioned at two ends of said shaft, said main shaft (210) is held in position between anti friction bearing a large diameter belt pulley (225) on rigidly mounted on said main shaft (210). 11. An improved vertical axis wind electricity generator as claimed in Claim 10 wherein said main pulley (225) drives a counter-shaft (232) via a belt pulley (230), said counter-shaft is positioned by bearings (234,236) and drives the electrical machines with three large belt pulleys (240, 243, 245) via friction clutches (250, 251, 252). 18 12. An improved vertical axis wind electricity generator as claimed in Claim 11 wherein said friction clutches are actuated by speed sensors which control the working of friction clutches depending on the speed of the wind. 13. An improved vertical axis wind electricity generator substantially as herein described with reference to the drawings. An improved vertical axis wind electricity generator which comprises a space frame, a plurality of guy-wires, a pair of vertical axis rotor assemblies, said space frame accommodates a plurality of vertical members supported by said guy-wires and cross members, said space frame being attached to vertical partitions at four corners thereof, said vertical axis rotor assemblies being held in position by means of radial support and thrust bearing at its top, each of said rotor assembly comprises two or more rotors in said rotor assemblies, said rotors located in the upper and lower portions and connected by cop-cone arrangement so that power available from wind in upper rotors is transmitted downwards and total power from wind is available at the bottom of the lowermost rotor wherein each rotor comprises a pair of blades of thin sheets curved across the vertical plane and assembled to have the concave side of each blade facing each other, each of said blade being held in position on a vertical girder structure and further each said blade being off-set from the center-line of the girder structure so that preferably 2/3m of the concave face of said blade remains uncovered by the said other blade.

Full Text

This invention relates to an improved vertical axis wind electricity generator.
Wind mills are known for hundreds of years, including vertical axis ones. The latest wind mills used for power generation comprise of aerodynamically designed, microprocessor controlled, rpm regulated blades, providing grid-quality electrical power. But these machines have an inherent drawback as they start operation from a wind speed around 5 meters/sec. Areas with prevalent wind speed of 5 meter/sec, and above are quite restricted. In India only a few districts of Andhra Pradesh, Gujarat and Tamil Nadu are having wind speed where modern wind electricity generators are viable due to above restriction.
Disadvantage experienced in the vertical axis machines of the prior art is the very low revolution rate of the blades due to various factors including the design thereof.
A still further disadvantage of known machine is the varying torque at different angular positions of the rotor within the same revolution.
In the prior art no vertical axis wind-electricity generators have been designed for large scale power generation.
2.

An object of the present invention is to mitigate the above drawback of the prior art.
A further object of the present invention is to reduce the cost of transforming kinetic energy of wind into mechanical energy.
A still another object of the present invention is to enhance the area of application of wind electricity generator particularly in a country like India where there is a tremendous shortage of electricity in rural areas.
The improved vertical axis wind electricity generator of the present invention has the following new features.
1. A complete new machine have been worked out with (1)
vertical axis blades to develop mechanical energy from wind
for driving pumps or electrical machines. The design provides
(2) an arrangement to couple a number of parallely running
vertical wind turbine to drive (3) centrally large electrical
machines or water pumps.
2. The machine excels in the quality that it operates from
a wind speed of about 2 meter/sec. Besides, it does not need
sophisticated technology such as aerodynamically designed
blades. As such, its per square meter cost is expected to
be much lower than that of the conventional machines. Via
bility in low wind makes the area of application much more
wide and manifold compared to that of the know machines.
3.

3. The combination of finish and geometry of the convex
and concave surface of the curved bLades have been carefully
designed to have efficiency in transformation of wind kinetic
energy by the vertical axis blades to much better result than
that of the known machines.
4. The two principal difficulties of the vertical axis
wind turbines known in- the literature, i.e. their very Low
revolution rate and varying torque at different angular positions
of the rotor within the same revolution are removed in the
machine design being disclosed.
According to this invention there is provided an improved vertical axis wind eLectricity generator comprising:
a space frame, a plurality of guy-wires, a pair of vertical, axis rotor assemblies, said space frame accommodates a plurality of verticaL members supported by said guy-wires and cross members, said space frame being attached to vertical partitions at four corners thereof, said vertical axis rotor assemblies being held in position by means of radiaL support and thrust bearing at its top, each of said rotor assembly comprises two or more rotors in said rotor assemblies, said rotors located in the upper and lower portions and connected by cup-cone arrangement so that power available from wind in upper rotors is transmitted downwards and total power from wind is available at the bottom of the lowermost rotor,
4.

wherein each rotor comprises a pair of blades of thin sheets curved across the vertical plane and assembled to have the concave side of each blade facing each other, each of said blade being held in position on a vertical girder structure and further each said blade being off-set from the center line of the girder structure so that preferably 2/3™ of the concave face of said blade remains uncovered by the said other blade.
- 5 -

The present invention will now be described in detail with reference to the accompanying drawings, wherein
Figure 1 shows a section of the vertical axis wind electricaly generator of the present invention ; Figure 2 shows sectional plan view of the rotor blades
of the electricity generator; Figure 3 shows the schematic diagram of plan view
of the blades of rotor assemblies; Figure 4 shows one of the lower most girder
structure with supports; and
Figure 5 shows the coupling of electrical machines/ water pump with the main pulley of the
generator.
With reference to the above drawings the improved vertical axis wind electricity generator and/or wind water pump (abbreviated hereinafter as IWEG ) consists of (1) a space frame (Figure 1) with vertical members (10,12,14) supported by guy-wires (15,16,17,18) and cross members (20, 22,24) holding inside it two vertical axis rotor-assemblies (30, 32). Vertical partitions (40, 42) are to be attached to the four corners of the space frame for more power output during low wind period, for concentrating the wind-flow to increase actual speed of wind while reaching the rotor-assemblies.
6

The rotor assemblies are held in position by means of radial supports (50,52) and thrust bearing (55) at top. Each rotor-assembly can be of height needed for the power generating capacity as required by the customer, larger height for larger capacity, but each such rotor-assembly consists of two or more rotors (60, 62,64) comprising a rotor-assembly (30) of smaller height. These smaller units are of said size and of optimum mechanical strength to enable them to withstand very high wind speeds . -Whatever, might ^ be the number of rotors in a rotor-assembly, the upper ones will bp connected to the lower ones by cup-cone arrangement (65"* so that power available from wind in upper rotors is transmitted downwards and total power from wind^ is available at the bottom of the lowermost rotor, even if one rotor is -nob* perfectly aligned to the others.
Each rotor (Figure 2) consists of pair of two blades (70, 72) made of thin sheets, curved across the vertical plane.; assembled such that the concave side of each blade faces each other, and they are held in position on a vertical girder-structure (75) and each blade is offset from the center-line of the girder-structure so that preferably about 2/3rd of the concave face (.80) (chord-length)

of the blade remains uncovered (82) by the other blade. The four ends (90,92,94,96) of the two curved blades are held in a same vertical plane (100) and this plane will be referred to in this specification as 'Principal Plane1 of the rotor in subsequent paragraphs. The radius of curvature (101) of the end of the blade away from the center-line is much smaller than (105) of the end nearer to the centre-line. The outer convex surface of the curved blades will be as smooth as possible to allow undisturbed flow of wind along them. The concave surface of the curved blades will be with horizontal and vertical strengthening ribs (106) which will
provide mechanical strength to the thin curved blades to withstand wind thrust, and also these will disallow smooth flow of wind tangential ly t.c the inner blade surface and make the wind flow turbulant..
Now, the curvature of the blades in one rotor-assembly will be arranged in opposite direction f(T2 5.,f1 30) of that of the other rotor-assembly (Figure 3). The principal plane of each rotor of a rotor-assembly is maintained at an angular displacement from that of all other rotors inside the space frame, placed above, below or at rive s i"de D'f it (all the principal planes 110, 112, 114, 120, 121 and 124 are at an angle with each other).
S

The girder-structure as illustrated in Figure 4, mentioned in the previous paragraph (75) is in fact replacement of a shaft for reducing the weight of the rotating mass, and is supposed to have at its top and bottom ends two round shafts (140, 145). In case wind-speed and resultant torque requires, the girder-structure will be replaced by a pipe. The upper end shaft (140) is held in position by an anti-friction bearing in a bearing-housing (150) supported from space frame by supporting connectors (50,52). Also this shaft (140) receive a cone (65) at its top end to hold in position the lower end of the shaft (145) of the immediate upper rotor, to which the cone is rigidly fixed. There is a cross pin (170) fixed at the upper end of the shaft (140) to receive rotational torque from the cone. The lower end shaft (145) of the girder-structure is to be supported on a vertical shaft (175) , (hereinafter called ."Stake Shaft" by a similar cone arrangement, to which the total rotating force is transmitted. The Stake Shaft (175) is held steadily by radial and thrust antifriction on bearings placed in a bearing-housing (180). This housing is rigidly grouted to the top of a concrete/ brick column (190) standing on ground. So, the assembly composed of 2 shafts and girder-structure (140, 75 and 145) can freely rotate along with the rotor blades mounted on it, between top and bottom antifriction bearings, along vertical axis, fixed in position in the space frame.

jr.
: 9

The stake shaft (175) is to have a bevel gear (201) mounted on it. This bevel gear rests on a thrust-plate (205) and will be receiving rotational torque from the stake shaft (175) through a friction clutch (206).
The same arrangement is to be repeated for the lower end of the girder-structure of the lowest rotor of the other rotor-assembly (Figure 4 shows for simplicity only the bevel gear of the other rotor-assembly). The bevel gears of both the rotor-assemblies are to be in same horizontal plane, and these two bevel gears will drive a common horizontal shaft (210) (hereinafter called "Main Shart") through two bevel pinions (211, 213) from two ends of the shaft. The main shaft (210) is held in position between anti-friction bearings in bearing housings (220). There is a large diameter belt pulley (225) rigidly mounted on the main shaft (210). This pulley will be hereinafter called "Main pulley".
The rotor-assembly rpm will vary directly with the wind speed. The rpm of the main pulley will be varying directly with the rpm of the rotor-assemblies, because of direct gearing.
The coupling of electrical machines/water pumps with main pulley is depicted in Figure 5. The main pulley (225) drives via a belt pulley (230.) of small diameter rigidly mounted on a shaft (232) (called "Counter Shaft.).
lo

The Counter Shaft (232) supported in position by bearings (234, 236) is to have 3 large beLt pulleys (240, 243, 245) on it, driving 3 electrical machines (or water pumps) (241,
242, 24 4) respectively. These three large pulleys (240,
243, 245) are to receiverotating power from Counter Shaft
via friction clutches (250, 251, 252). The clutches will
engage the large (240), medium (243) or small (245) puLley
respectively during low, medium or high wind speed. In turn,
3 electrical machines/water pumps (24*1 , 242, 244 will be
driven respectively during low, medium or high wind. These
machines are of smalI, medium and high capacity, operating
during low, medium and high wind speed respectively. More
pulleys/clutches/electrical machines wiLl be put to parallel
operation in areas where the operating range of wind speed
will be very wide.
The selective engagement of the clutches wiII be actuated by a speed sensor, sensing rpm of any one of the rotor-assemblies. The speed sensor will actuate the clutch (206) to disenage the bevel gears (201 ) from the rotor-assemblies during very high winds to save the equipments from damage due to over speed.
Each of the electrical machines experiences a speed variations, though the range of variation is much less than the total range of wind speed variation. Output voltage of the electrical machines is regulated by field-current
II

control (not shown), to provide constant voltage variabLe amperes direct current output (as in automobile electrical machines). The machines running paraLlel wil I deliver the power to a common busbar or a storage battery.
In case water pumps are driven, the water will1, be pumped up to the overhead storage tank, placed on top of Space Frame either to be used for driving water wheels/water turbines, to generator electricity in turn, or for any other puprose desired by the customer.
For large power requirements, if the required height of the space frame a~pp'eaxs unsafe and costly for the local high wind conditions, a row of IWEG may be constructed but excluding the counter shaft, the speed sensor and the electrical machines. A common counter shaft will be constructed to be driven by all main pulleys from the different IWEG's, by belts covered for protection from weather and the single counter shaft is extended to reach all the main pulleys, which will receive power from alL the IWEG's delivering power to a single set of electrical machines or pumps, located in a power-house. A single speed sensor, getting speed signal from any one of the rotor-assemblies, wi II control all the clutches in the group of IWEG's. The row of IWEG will be constructed 'in a direction across the direction of maximum wind flow duration.
The rotor-assemblies of the machine is exposed to the atmosphere along with the upper part of the space structure. The bevel gears, the friction c lutches, the
\2-

pulleys with the electrical machines, the control gears and the busbar with electrical switches etc are located in a covered area or room, preferably built with bricks between the vertical members of the space frame and a sloping roof below the lowest end of the rotor-assemblies.
Wind from any direction causes one of the rotor-assemblies to rotate in clockwise direction and the other in anti-clockwise direction (Figure 3). The arrangement of the bevel gears cause the main shaft to be driven in one direction only by both of the rotor-assemblies.
The rotation is caused by kinetic energy of the wind transformed to mechanical energy, partly by causing
thrust drag force in the concave side of the blades, and
force partly caused by the lift/created by the tangential attack
of the flowing wind at a low angle on the convex (smoother) surface of the curved blades. The generation of lift component in the concave surface is negated by the presence of ribs which deters smooth tangential flow of wind along the concave side.
The arrangement of belt pulleys have been planned in such a manner that the high-torque low rpm rotating force from the rotor-assemblies is transformed to a higher rpm suitable to operate electrical machines or pumps. As has been already explained, two or more electrical machines have been connected to operate parallel, but one only at a time, with a capacity matching to the power available from wind at the particular speed. This matching of the input power and output power increases system efficiency.
j*. \$

The mutual angular displacement position of different rotor blades (Figure 3) in the rotor assemblies will result in more uniform torque within a revolution of a rotor-assembly.
The cone arrangement (Figure 5) at the lower end of rotors will accommodate mutual misalignment between the axis of rotation of the rotors of same rotor-assembly because of deflection due to wind thrust, by providing the required flexibility in a simple manner.
The electrical machines may be replaced by water pumps. A combination of electrical machines and water pumps may also be possible. In that case, the wind energy will directly be used to pump water. The pumped water may either be used directLy for,, different purposes or may be stored in a tank at the top of the space frame for subsequently driving a water wheel or a water turbine for producing electrical power, during low winds, to make up the short supply for electricity from the wind force directly.
It will be apprecated by a person skilled in the art that obvious alterations and/or modifications are possible to be included in the vertical axis wind electricity generator of the invention and therefore the above description is not exhaustive and will not unnecessarily limit the ,s.cape of this invention.

WE CLAIM:
1. An improved vertical axis wind electricity generator comprising -
a space frame (1), a plurality of guy-wires (15, 16, 17, 18), a pair of vertical axis rotor assemblies (30, 32), said space frame accommodates a plurality of vertical members (10, 12, 14) supported by said guy-wires and cross members (20, 22, 24), said space frame being attached to vertical partitions (40, 42) at four corners thereof, said vertical axis rotor assemblies being held in position by means of radial support (50, 52) and thrust bearing (55) at its top, each of said rotor assembly comprises two or more rotors (60, 62, 64) in said rotor assemblies, said rotors located in the upper and lower portions and connected by(§ 15

2. An improved vertical axis wind electricity generator as claimed in
Claim 1 wherein four ends (90, 92, 94, 96) of said two concave plates are
held in principal plane.
3. An improved vertical axis wind electricity generator as claimed in
any of Claims 1 or 2 wherein the radius of curvature (101) oftheendof
said blade which is positioned away from the center line is much smaller
than the radius of curvature (105) of the blade located near the center-line.
4. An improved vertical axis wind electricity generator as claimed in
Claim 3 wherein the outer convex surface of the curved blade is smooth
and the inner concave surface of said curved blade is provided with
horizontal and vertical strengthening ribs (106).
5. An improved vertical axis wind electricity generator as claimed in
Claim 4 wherein the curvature of blades in one rotor assembly is arranged
in opposite direction (125, 130) to the other.
6. An improved vertical axis wind electricity generator as claimed in
any of the preceding claims wherein the principal plane from said rotor
assembly is maintained at an angular displacement of that of all other
rotors located inside the space frame.
16

7. An improved vertical axis wind electricity generator as claimed in
Claim 1 wherein said girder structure is replaced by a pipe, said girder
structure being provided at the top and bottom ends two round shafts (140,
145), said upper end shaft is held in position by an anti-friction bearing
placed in a bearing housing (150) supported from space frame by
supporting connectors (50, 52), said shaft (140) is fitted to a cone (65) at
its top end to hold in position the lower end of the shaft (145) of the
immediate upper end rotor in which said cone is rigidly fixed, a cross pin
(170) is fixed at the upper end of said shaft (140) to receive rotational
torque from said cone, the lower end of said shaft (145) of the lowermost
girder structure is supported on a vertical shaft (175) by another cone
arrangement to which the total rotating force is transmitted.
8. An improved vertical axis wind electricity generator as claimed in
any of the preceding claims wherein said vertical shaft (175) is provded
with a bevel gear (201) mounted on it and said bevel gear is rested on a
thrust-plate (205) to receive rotational torque from said vertical shaft
through a friction clutch (206).
17

9. An improved vertical axis wind electricity generator as claimed in
any of Claims 1, 7 or 8 which optionally comprises at the lower end of
the girder structure of the lowest rotor of the other rotor assembly a bevel
gear which is connected to the other bevel gear of the said other rotor
assembly through a common horizontal shaft (210).
10. An improved vertical axis wind electricity generator as claimed in
Claim 9 wherein said common shaft connecting the bevel gears of rotor
assemblies is held through two bevel pinions (211,213) positioned at two
ends of said shaft, said main shaft (210) is held in position between anti
friction bearing a large diameter belt pulley (225) on rigidly mounted on
said main shaft (210).
11. An improved vertical axis wind electricity generator as claimed in
Claim 10 wherein said main pulley (225) drives a counter-shaft (232) via
a belt pulley (230), said counter-shaft is positioned by bearings (234,236)
and drives the electrical machines with three large belt pulleys (240, 243,
245) via friction clutches (250, 251, 252).
18

12. An improved vertical axis wind electricity generator as claimed in
Claim 11 wherein said friction clutches are actuated by speed sensors
which control the working of friction clutches depending on the speed of
the wind.
13. An improved vertical axis wind electricity generator substantially as
herein described with reference to the drawings.
An improved vertical axis wind electricity generator which comprises a space frame, a plurality of guy-wires, a pair of vertical axis rotor assemblies, said space frame accommodates a plurality of vertical members supported by said guy-wires and cross members, said space frame being attached to vertical partitions at four corners thereof, said vertical axis rotor assemblies being held in position by means of radial support and thrust bearing at its top, each of said rotor assembly comprises two or more rotors in said rotor assemblies, said rotors located in the upper and lower portions and connected by cop-cone arrangement so that power available from wind in upper rotors is transmitted downwards and total power from wind is available at the bottom of the lowermost rotor wherein each rotor comprises a pair of blades of thin sheets curved across the vertical plane and assembled to have the concave side of each blade facing each other, each of said blade being held in position on a vertical girder structure and further each said blade being off-set from the center-line of the girder structure so that preferably 2/3m of the concave face of said blade remains uncovered by the said other blade.

Documents:

« Previous Patent

Next Patent »

Patent Number

202555

Indian Patent Application Number

04/CAL/1999

PG Journal Number

09/2007

Publication Date

02-Mar-2007

Grant Date

02-Mar-2007

Date of Filing

01-Jan-1999

Name of Patentee

RABI MUKHOPADHYAY

Applicant Address

FLAT-B/3 IRONSIDE CO-OPERATIVE HOUSING SOCIETY LTD.,11/3B OLD BALLYGUNGE 2ND LANE CALCUTTA-700 019.

Inventors:

#	Inventor's Name	Inventor's Address
1	PARTHASARATHI MUKHOPADHYAY.	FLAT B/3 IRONSIDE CO-OPERATIVE HOUSING SOCIETYLTD. 11/3B,OLD BALLYGUNGE 2ND LANE, CALCUTTA 700 019.
2	RABI MUKHOPADHYAY	FLAT-B/3 IRONSIDE CO-OPERATIVE HOUSING SOCIETY LTD.,11/3B OLD BALLYGUNGE 2ND LANE CALCUTTA-700 019.

PCT International Classification Number

FO3D1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA