THREE WING RADIAL WIND-TURBINE

Technical Field

This invention belongs to a field of mechanisms driven by wind with axis mostly perpendicular on wind direction.

By international classification of patents its label is MKη(7): F03D3/02.

Technical Problem

How to make wind-turbine on handicraftsman way (in conditions of lower technical liabilities), which is compact, noiseless, and does not represent menace to living creatures (to be applicable in urban ambient), and which without changes of rotor position or its geometry withstands winds up to 180km/h requiring besides minimal or no maintenance at all.

Background Art

Wind-turbines are already 1000 years known as energy sources, and during 19. Century were mass used for driving mills, sawmills, or water-pumps particularly in Holland, Denmark and USA. Their power utility coefficient can't overpass maximum of 16/27 i.e. 59.3%, theoretically stated by Betz.

According to mutual position of rotors rotating shaft toward wind blowing direction, we differentiate them on axial (wind direction is along rotor shaft) and radial (wind direction is perpendicular to rotor shaft).

Axial wind-turbines:

They dominate in usage. First three-wing axial wind-turbine intended to drive electric generator was constructed in Denmark about mid of previous century, and on this basis were developed almost all wind-turbines for such application known today. Through time, wing profiles, technology of wing materials, transmission, and mandatory electric generator with its controller are improved by technical progress. In electro-energetic economy of developed countries, assemblages of wind-turbines are introduced in plantation form. Here an compromise of nominal power, production costs and working age for individual turbine- member already achieves 0.06 euro price per generated KWh. Larger wings length on axial wind-turbines specially contributes to higher nominal power and torque on driving shaft, but

as they are longer their breakage rather could be induced at wind speeds over 15m/s. To overrun some wise this problem, wings are to be made of hard and light but expensive material (like carbon fiber) or some cheaper but heavier one. While first approach could make production price unacceptable, the second lowers working efficiency because increased rotors inertia decelerates required adjustment to wind direction changes, especially by direction-changeable short-lasted winds. Active adjustment and protection (rotating wings around their own axes and/or inclining the whole rotor up to horizontal) is as an expensive solution reserved mostly for very powerful wind-turbines. Specific imperfections of axial wind-turbines are: working suspension often for winds over 15m/s, large space occupied by rotor, high tower needed for its placement (proportionally to wings length) and possibility to cause dangerous (sometimes lethal) body injuries to living creatures in case of contacting rotor while it swings. At the other side, high wind power utility by modern axial wind- turbines (peak 50% and average 45%), gives them precedence when projected power is several tenths kilowatts or more.

Radial wind-turbines:

As opposed to axial, they do not need adjustment of rotor position to wind direction changes, but have lower wind power utility. Known types of those turbines are from the authors Sigrid Savonius (Finland), Georges Darrieus (France) and Rivieres (French patent nr. 2659391). Highest coefficient of wind power utility (peak 40% and average 35%) has Darrieus turbine, composed of two or more thin, slightly twisted band-like wings shaped as »C« letter. Its disadvantages are: inability to start independently thanking to balanced drive moment, and large space occupied by straining ropes for shaft fixing on some bigger constructions. This type was the only one commercially used (last known such generator from Quebec-Canada of 4200KW with two-wings rotor of 100m diameter doesn't work yet). Riviere-s turbine, with laminar wings rotating hereto around their own axes, is in experimental status at Estonian Agricultural University »Kreutzwaldi« from Tartu. Savonius turbine, with rotor compounded of two cylindrical partially overlapped surfaces turned each to another by concave part, has least wind power utility (peak 15%). It has advantages that doesn't occupy large space and can't hurt living creatures in direct contact with rotor during stroke. The only one producer I know, of small power turbines in this type version is »Windside« from Finland.

In Table 1 is, toward relevant characteristics, given comparative background art overview for known wind-turbine types versus three wing radial wind-turbine:

Table 1

Disclosure of Invention

To enable production of three wing radial wind-turbine in lower technical level liability conditions, built in materials are chosen to be available everywhere on the planet. Those are: standard steel tubes, (round and square-shaped) rods and tin, usual connective elements (bolts, washers and rivets), standard (radial-axial and needle) roller bearings, plastic (black polyacethale) rods, thin plates (UV-stabilized polyethylene) and a piece of (rubber-canvas) transportation ribbon. Except easy available and low pricing material, production could be carried out on handicraftsman way by using tools in typical metal-working workshop (lathe, grinder for cutting/honing steel shapes, borer, tubes flexing machine, welding device and standard set of hand-tools). Dimensions of invention are adapted to this kind of production, reducing specimen to be made as choice of value from range 250W to 2500W for maximum allowed mechanical usable power (stands at approximately 15m/s wind speed, and should stay unchanged for speeds over that limit to prevent construction strength violations).

Providing this turbine to be applicable in urban ambient, rotor and stator are specially shaped and connected in compact block through noiseless bearings. Rotor in run-up here softly

pushes with smooth and orbicular surface impediments on its tracing, so is harmless in direct contact with living creatures. Three cylindrically shaped wings, bended spirally along rotor axis for 120° each, expose to winds from all directions unchangeable aerodynamic profile and size of rotational surface, so it moves uniformly and without jerks. Aerodynamic configuration those three wings, supported by central opening for drift-through, produces average utility coefficient of about 20%. To simplify production and make it cheaper, wings are formed without previous grade by mold, press or thermal treatment. Aerodynamic shape and firmness are provided by the rotors skeleton. On its ribs, by rivets are clenched original cut revetment elements made of UV-stabilized, laminar and flexible polyethylene, previously adapted by hand.

Solution for technical resistivity problem against wind speeds up to 180km/h is found through original construction of stator and rotors skeleton, both made of standard constructive steel tubes. Except firmness needed, stator cage characterize: minimal material consumption, minimal rotor screening, small passive surface exposed to wind strokes, separated upper section for rotor from lower section (for lodging devices driven) and convenience to embed bearings.

Innovative connection between stator and rotor over two elements called "adjusters" solves problems like: to compensate rotational axis deviation from Tightness for long shaft of spiral windmill after production, oscillations of its length by working, its deviation from perpendicularity by installation and also to avoid lubrication of high situated upper bearing during maintenance.

Three wing wind-turbine, as compact block for built-in, facilitates various installation modes in places where it should be used and has unpretentious room demands. As example, such one turbine (without stand) with allowed usable power limited to 2500W could be placed in space described with cylinder 2m in diameter and 6m high.

Brief Description of Drawings

Fig. 1 Axonometric sketch of three wing wind-turbine, composed of stator (1), rotor (2) and optionally: stand (3) with pedestal (4) Fig. 2 Axonometric sketch of stator (1), composed of three pylons (5) joined by: upper tripod (6), inner tripod (7) and lower tripod (8) - which could be welded on optional stand (3). Positions of lower adjuster (9) and upper adjuster (10) are indicated too.

Fig. 3 Top view on upper tripod (6), which with other two tripods (7) and (8) provides firmness needed for stator (1)

Fig. 4 Top view on one of three rays (15) of tripod (6), equipped with welded pad for fastening through four holes on stator (1) pylons Fig. 5 Axonometric sketch of disjunctive bond between tripod (6) and one of three pylons (5) in stator (1) frame, composed of four assemblages each containing screw-bolt (11), pair of tooth-washers (12), pair of flat washers (13) and screw-nut (14).

Fig. 6 Top view on one of five rib triplets (16) which provides firmness needed for rotor (2) by forming its skeleton Fig. 7 Top view on one of three ribs (17) composing triplet (16)

Fig. 8 Axonometric drawing of rotors (2) skeleton shows lower shaft termination (18) and upper shaft termination (19), wedges (20) and safeties (21) for their fastening in tubular shaft (22) with protective cap (23), as also insignia: D-diameter of ribs (17) semicircle and H-distance between neighboring rib triplets (16) Fig. 9 Front view on rotors (2) skeleton made of tubular shaft (22) on which are disposed and welded five rib triplets (16) labeled by letters A, B, C, D and E

Fig.10 Top view on rotors (2) skeleton shows mutual position of five rib triplets rotated consecutively by 30° in the same direction. Labels on rib terminations A, B, C, D and E are used to establish unambiguous correspondence with their positions on Fig. 9 Fig.11 Drawing of cut for one of twelve identical revetment elements (24), with edges marked as (a, b, c and d), referent angle (α)-(100.3°) and overruns (pi) and (p2) required for holding and riveting.

Fig.12 Drawing of rotors front view. Three wings (25), formed by riveting twelve revetment elements (24) on rotors skeleton ribs, are shown meshy for sake of easier insight in whole

Fig.13, 14, 15, and 16 respectively illustrates air-flow redistribution and ensuing forces on rotors transversal cross-section, in 4 positions originated from its consecutive rotations for 30°. Associated legend is common for all four Fig.-s

Fig.17 Axonometric drawing of lower rotors shaft termination imbedding, shows tubular rotors shaft (22) with protective cap (23), its lower termination (18), radial-axial bearing (26), inner tripod (7) in which opening is welded tin triangle (27) equipped with welded saddle (28) for radial-axial bearing (26) and lower adjuster (9) consisting needle-bearing (31) and tin triangle (29) with saddle (30) for this bearing.

Lower adjuster is fixed on tripod (7) through three connections each containing screw-bolt (32), pair of tooth-washers (33), pair of wide flat-washers (34), wide tooth-washer (35) and screw-nut (36)

Fig.18 Axonometric drawing of upper rotors shaft termination imbedding, shows tubular rotors shaft (22), its upper termination (19), upper stators tripod (6) and upper adjuster (10) containing triangle (37) made of flexible transportation tape, needle- bearing (38) with its lower half-saddle (39) and upper half-saddle (40) connected through three connections each containing screw-bolt (41), tooth- washer (42) and screw-nut (43). Upper adjuster (10) is fixed on upper tripod (6) through three connections each containing screw-bolt (44), pair of tooth-washers (33), pair of wide flat-washers (34), wide tooth-washer (35) and screw-nut (36)

Best Mode for Carrying out of the invention

Look of three wing wind-turbine is shown on Fig.l. It contains stator (1) and rotor (2), while stand (3) with pedestal (4) are given only as one option for installation and are not a subject of further description.

Most of building elements for this turbine are round and square steel tube segments and tin clippings, so defaulted way of their assembling is welding in contact points and along contact edges. Dismountable connections will be peculiarly signalized. Stator (1) is shown on Fig.2. Its cage contains three pylons (5) joined by tripods (6), (7) and (8), all with 120° between rays. Pylons (5) and upper tripod (6) are made from connatural square tubes, while inner tripod (7) and lower tripod (8) are made from connatural rectangular tubes, whose shorter edge on cross section is equal to edge on cross section of square tubes used. On Fig.2 are also shown positions of lower adjuster (9) and upper adjuster (10), by which is on innovative way solved rotor in stator embedding (more details about it later).

Key-elements for providing spiral windmill resistivity on wind-speeds up to 180km/h are shown on Fig.3, 4 and 5. Those are previously mentioned three rigid tripods, and planar view of upper tripod (6) is given on Fig.3. It contains three equal rays (15) shown on Fig.4 mutually welded to form one defined triangular equilateral central opening. Rays are equipped with welded tin pads, each disposing with 4 holes to be connected by bolts to corresponding pads on pylons (5) of stator (1), as shows axonometric sketch on Fig.5. When tripods (6) and (8) are disassembled, cage integrity provides inner tripod (7) with rays

welded on pylons (5), as shown on Fig.2. Fig.6 shows one rib triplet (16) formed by welding three equal ribs (17) mutually, with neighboring angle 120° between them. Ribs (17) are made by bending corresponding steel tube in semicircle, as shown on Fig.7. Central openings of all rib triplets are to be equal and to allow narrowly slipping on tubular shaft (22) of rotor (2). On a given distance and rotated 30° consecutively, five of such triplets (16) form rotors (2) firm skeleton after they are welded on shaft (22) in planes perpendicular on it.

Axonometric representation of rotors skeleton gives Fig.8. To preserve real mutual proportion between constitutive elements on given paper-format, only three of five rib- triplets (16), making with tubular shaft (22) unity, are shown. In rotors (2) construction a basic measure is inner diameter of ribs semicircle, labeled on this figure with (D), while with (H) is labeled distance between any two neighboring rib triplets. Lower shaft termination (18) is made of steel rod and upper (19) of polyacethale rod, both shaped by lathe treatment. In openings on tubular shaft ends, shaft-terminations are fixed by their in draft till superposition of transversal holes through which wedge (20) is pulled through and insured on its ends by safeties (21). Previously, on lower ending of tubular shaft (22) protective cap (23), made of black polyacethale, is slipped and glued, to protect from dust and precipitations bearings and potential housing placed in lower section of stator (1). Insight in rotors (2) skeleton with all five rib-triplets (16) welded on tubular shaft (22) gives Fig.9 as front view and Fig.10 as top view. Between those views, is with letter marks (A, B, C, D and E), unique correspondence between matching rib triplets established. Except ensuring firmness needed, rotors skeleton represents also guide for aerodynamic shaping wings on this turbine. Base for one wing represents series of five vertically neighboring ribs, rotated each for 30° consecutively. Per each of three such series, wings are formed by riveting four revetment elements, hence twelve of them in total. Revetment element (24), whose cut is shown on Fig.11, is made from sheet of UV-stabile polyethylene with convenient thickness. On figure are with (a, b, c, d) labeled edges of trapezoid which represents revetment element in plane state. Edges (a) and (c) represent respectively lower and upper line for riveting them on rotors skeleton ribs, whilst (b) and (d) represent respectively part of outer and inner wing edge. Individual revetment element is mounted on a pair of vertically neighboring ribs so that is first snuggled over outer side of lower rib, till its ending. Then, along marked lower line for riveting (a), overlapped over contact line with this rib, there are 4 rivets to be nailed. Overrun (pi), under lower line for riveting (a), should have height equal to ribs tube outer

diameter. Upper part of revetment element should be snuggled over inner side of upper rib, and riveted on it with 3 rivets, after marked line for riveting (c) is slipped by hand over inner contact line with this rib to overlap till its ending. Overrun (p2) is used in this operation as handrail and that is why should have height at least 100mm, so then ought to cut it to height equal to outer diameter of ribs tube. Revetment elements (24), stringed over ribs like tile, form three wings (25) shown on Fig.12 in front view and meshy form to simulate transparency.

Fig.13, 14, 15 and 16 on clear phenomenological way illustrates principle of how air-flow acts on three-wing rotor. Four stances of one rotors transversal cross section are presented, originated by consecutive shaft rotations for 30° in the same direction, the same as to observe in one moment aerodynamic situations on transversal cross sections of four successive rib-triplets. To every stance is associated sketch of respondent air-flow cross section, which in role of driving medium causes forces shown on rotor. Observing from arriving wind flow direction, thanking to angle of 120° between wings, convex surface of wing succeeding in rotating direction narrows air stream and so accelerated directs it on concave surface of precursor wing. Except that ensued acceleration magnifies pressure on that wing, contribution to rotating moment performs also displacement of central stream line to its periphery. One portion of air flow passes through central opening and acts at wing in background of view on rotor, whence by its participation usability coefficient of wind-power raises. On figures is noticeable that, alongside with pressure, on some part of rotors surface suction takes effect too. As rotational speed of turbine rises (with wind speed increase), more conspicuous becomes Mach-effect which also acts in favor of rotating moment. Over and above, while one part of rotor by combined pressure on concave and suction on convex surfaces contributes turbine to work, lesser part of convex surface (used for air flow directing) inhibits it. To eliminate this inhibition using rotating shelter (in addition to usability coefficient of wind-power) is not taken into account here, because next to price will grow also stators surface exposed to wind, violating constructions stability. Thanking to its heaviness and shape, rotor of three wing radial wind-turbine produces gyroscopic moment, whose progressive growth with raise of wind speed induces proportional stabilizing effect in favor of construction resistivity on stormy winds.

At three wing radial wind-turbine, nestling of rotor in stator is adjustable. For this purpose are used adjusters, formed by placing saddle for needle-bearing and a bearing alone in center of equilateral trigonous basis, which has in corners drilled openings wider for minimum of

4mm then diameter of screw-bolts for fastening it on corresponding tripod. Before tighten screws to fasten adjuster on tripod, it could be moved horizontally in all directions for difference between openings in corners and diameter of screw-bolt bodies through them. This allows centering of shaft termination which passes through needle-bearing of adjuster. So is ensured perpendicularity and rightness for rotational axis of lower shaft termination (18), intended to drive working devices. Solution shows Fig.17 in details, where lower shaft termination (18) is set through a pair of standard roller bearings so that carrying radial-axial type (26) is rigidly coupled on inner stators tripod (7), while directing needle type (31) is placed on tin triangle (29) of adjuster (9), which after adjusted perpendicularity by its horizontal movement is to be fasten on tripod (7) with screws (32). Innovative solution for nestling upper shaft termination (19), shown on Fig.18, compensates deviation from rightness for whole shaft and its length oscillations, allowing also its perpendicularity adjustment. Here is needle-bearing (38) implanted in flexible canvas triangle (37) of adjuster (10), eliminating expensive self-adjusting bearing, which has less compensation facilities besides. Lubricating of upper bearing, difficult to be accessed on high constructions, is avoided by making upper shaft termination (19) from black polyacethale rod and half- saddles (39) and (40) as also needle bearing (38) (with stainless needles) from the same material. One feature more for this solution is its resistivity on corrosive atmospheres (sprinkle salty water, acetous fog etc.). Thanks to compact and self-carrying construction, three wing radial wind-turbine relieves adaptability of installation to circumstances dictated by choice of location and exploitation mode. Fig.l shows stand (3) for elevating and pedestal (4), as installation variant in cases of aerodynamically rough ground (scabrous and/or overgrown by vegetation), natural or artificial screens, too narrow space for pedestrians/vehicles motions or appearance of high deposits (atmospheric, by wind or other kind). In case of disposable natural or artificial platform with adequate portability and open to winds, lower stators tripod (8) could be directly (by screws or other way) fixed to it (rocks, crafts, flat roofs of buildings and vehicles, towers, eaves etc.). For temporal applications it is enough to put down this wind- turbine on chosen position and secure it only from horizontal sliding, because gyroscopic stabilizing moment of rotor prevents wind to bring it down. Except uprightly turbine could be mounted under some angle or horizontally in directed air flows (canyons, rifts between buildings, tunnels, bridges, overpasses etc.). Side installation on slanted or vertical base is to be performed using consoles (walls, banisters, pylons, chimneys etc.). Finally, as compact

and self-carrying construction with inherent gyroscopic stabilizing moment, three wing radial wind-turbine could be installed by hanging it on upper tripod (6), when in production upper tripod (6) and (robust) lower tripod (8) should change places.

Table 2 contains ordered set of expressions for defining constructions parameters needed to produce specimens of three wing radial wind-turbine. By choosing one value from extent

250W to 2500W as upper limit for usable mechanical power on turbines driving shaft, indirectly all construction parameters are defined. Starting with this value, further adopted results from previous expressions are only to be substituted in following, going from top of table till its bottom. Except adopted value for usable mechanical power limit "P" in watts, all dimensions used in table are in millimeters, so conversion in other units before substituting adopted values from one expression to another is not needed. Adopting of calculated values is carried out toward standardization by mediation through following operators:

NIN - Nearest Integer Number NINn - Nearest Integer Number divisible by "n" NSV - Nearest Standard Value

Table 2

Industrial Applicability

Owing to variable wind-speed, energetic income of three wing radial wind-turbine is to be planed statistically, on meteorological recording basis in target territory for several years. Hence, though with original mechanical energy could during windy days drive smaller mill, pump, compressor etc., optimal use of invention means to convert produced mechanical energy into electrical and store it in accumulator battery to be used occasionally or periodically. Such applications could be: safety electric sources in hospitals, production

plants, touristic objects or any place where drops of main energetic network could be critical, but on places where energy supplying is aggravated or lacks it could be supplementary or even main source (Fig.l).