Features of the present invention will now be more particularly described, by way of example, with reference to the accompanying schematic drawings, in which: 30 Figure 1 is a longitudinal section through one embodiment of a power harvesting device according to the invention, installed in a pipe; Figures 2 and 3 illustrate variants of the device of Figure 1; 35 Figure 4 is an end view of a further variant of the device of Figure 1, installed in a pipe; WO 2007/071975 PCT/GB2006/004777 4 Figure 5 is a side view of another embodiment of a power harvesting device according to the invention including a force-amplifying mechanism, installed in a pipe; Figure 6 is a side view of a further embodiment of a power harvesting device 5 according to the invention, installed in a pipe; Figure 7 is a side view schematically illustrating the interior of a further embodiment of a power harvesting device according to the invention; 10 Figure 8 is a pictorial view of a variant of the device of Figure 7 installed in a pipe, with the pipe largely broken away; Figure 9 is a side view schematically illustrating the interior of another variant of the device of Figure 7; 15 Figures 10 and 11 are schematic sections through fittings comprising several devices according to the invention; and Figure 12 is a pictorial -view of a pair of devices according to a further embodiment of 20 the invention installed in a pipe, with the pipe largely broken away.
- FIG. 5A depicts a perspective view of another embodiment of a kinetic energy conversion system
- Aprender técnicas de meditación y relajación
- Frota la preparación sobre la zona afectada, aplicando un suave masaje
- Dolor crónico generalizado
- La mujer inseminada debe permanecer entre 10 y 30 minutos acostada
- Golpe de palma (circular, frontal)
- Rasurar en dirección al vello
Improved performance may be derived from the device of Figure 7 if the magnet 15 is suspended within the chamber between a pair of springs (not shown) and the magnet/spring system is tuned so as to resonate within the chamber at the same 30 frequency as but in opposite phase to the resonance of the body 1/arm 3 system.
Dolor Espalda Baja
35 It is observed that in use of the embodiment of Figure 4 the cylindrical piezoelectric stacks 10 will also tend to shed a Karman vortex trail within the flow of fluid passing through pipe 2, and at right angles to the trail shed from the body 1. Since the blade WO 2007/071975 PCT/GB2006/004777 7 3 is stiff in the direction of the dynamic loading induced by the vortices from the stacks 10, however, this phenomenon should not interfere with the essentially uniplanar oscillation of the body1 and blade 3. 5 Since the electrical output of a piezoelectric material is generally proportional to the level of induced stress but such materials exhibit relatively small strain rates even under high forces, it may be advantageous in a device according to the invention, which utilises piezoelectric energy conversion, to employ some form of mechanical linkage between the oscillating body/support system and the piezoelectric material 10 which converts the relatively high displacement/low force motion of the former to a relatively low displacement/high force action applied to the latter.
35 In accordance with known fluid dynamic principles, when the body 1 is subjected to a flow of fluid through the pipe 2 within a certain Reynolds number range, notionally indicated by the arrow F in Figure 1, vortices will tend to be shed regularly in an WO 2007/071975 PCT/GB2006/004777 5 alternating fashion from the upper and lower (as viewed) sides of the body, establishing a so-called Karman vortex trail as notionally indicated at v in Figure 1. The corresponding alternating dynamic loading on the body 1 will tend to cause the latter to oscillate in the vertical (as viewed) plane as notionally indicated by the 5 arrows X, with consequent flexure of the cantilever arm support constituted by blade 3. Flexure of the blade 3 will stress each piezoelectric patch 5 alternately in compression and tension, in opposite phase to each other, thereby generating electric charges from the patches in pulses corresponding to the oscillation of the body 1/blade 3 system.
Dolor Muscular Brazo
10 If the fluid within which the device of Figure 6 operates has a ferrous content then there can be a build up of debris on the magnetised body 1, adversely affecting the performance of the device. An alternative configuration utilising magnetic induction for power conversion, and which addresses this problem by shielding the magnetic 15 element from the flow, is shown in Figure 7. Within the body 1 in this case a bar-like permanent magnet 15 is trapped in a chamber 16 extending crosswise to the axis of the body but with freedom to slide therein so that as the body oscillates in use of the device, (up and down in the orientation shown in the Figure), the magnet is impelled to repeatedly shuttle from one end of the chamber to the other, by virtue its own 20 inertia. In the direction of their shorter axes the elliptical springs 13 are each attached between the blade 3 and the adjacent wall of the pipe 2. 20 In use of the device of Figure 5, oscillation of the body 1 and consequent flexure of the blade 3 (upwards and downwards from the illustrated central position in the orientation of the pipe viewed in the Figure) causes each elliptical spring 13 to be alternately squeezed and expanded by the blade, (in opposite phase to each other), 25 along the shorter axis of the respective ellipse.
In particular the adverse conditions experienced downhole generally make it unfeasible to employ conventional fluid-powered generation methods based on turbines or any other devices which depend on rotating or otherwise moving parts with mechanical 30 bearings, linkages or other such interfaces. Devices of the kind illustrated in Figure 1 have been tested over a range of flowrates and using a range of fluids, namely (i) single phase water, (ii) single phase oil, (iii) 15 two-phase oil and water, and (iv) multiphase gas, oil and water, with Reynolds numbers ranging from 4,500 to 312,000. Over a useful range of flowrates in all three of the liquid phase examples, the observed behaviour of the devices was to oscillate in the flow at the respective natural frequency of the body/blade system, the amplitude of the oscillation increasing up to a maximum where the vortex shedding 20 frequency associated with the flow velocity matched the natural frequency of the device (i.e.
The resultant regular vortex pattern is generally known as a Karman vortex trail or “street”, being so named 5 because of Theodore von Karman’s initial studies of the stability of these patterns. 5 It is particularly preferable if, in use of a device according to the invention, vortex shedding from the blunt body occurs at or sufficiently close to the natural frequency WO 2007/071975 PCT/GB2006/004777 3 of the body/support system (or a harmonic thereof) so that resonance of the latter occurs. If necessary to prevent the piezoelectric material becoming overstrained and risking fracture, stops 30 may be incorporated in the design to limit the displacement of the body 1 and consequent flexure of the blade 3. Figures 2 and 3 illustrate variants of the structure of the device shown in Figure 1. 35 In Figure 2, instead of the thin piezoelectric patches 5 along the length of the blade 3, relatively high volume piezoelectric elements 6 are located between the fixed mount WO 2007/071975 PCT/GB2006/004777 6 4 and the blade 3 at its root, which is the most highly stressed region of the device when the body 1 oscillates.
Dolor Sordo En El Pecho
The behaviour in multiphase gas, oil and water was more intermittent 25 and transient but most of the dynamic behaviour of the devices still occurred at the respective natural frequency. Dolor de rodilla al agacharme y levantarme . 0 generation downhole. However devices according to the invention are not restricted to such application and may be found more generally useful for power generation by interaction with a wide variety of fluids flowing e.g.
5 The invention is particularly concerned with devices for use in generating power from fluids flowing downhole in oil and gas wells. In either of the embodiments of Figures 7 and 9 a plurality of chambers 16 together 20 with magnets, coils and (where applicable) cores could be provided, spaced across the width of the body 1. In practice it is likely that a multiplicity of devices according to the invention will be installed to collectively meet the power demands of downhole equipment. Operating in this mode will maximise the relative speed of traverse of the magnet 15 through the coil 17 and consequently maximise the rate of change of flux and correspondingly induced voltage in the coil. Electrical leads (not shown) extend out of the device from the coil 17 to a circuit from which an associated battery or capacitor can be charged for powering downhole instrumentation or other 25 electrical equipment.
Dolor Neuropatico Herpes
In Figure 3, a two-piece cantilever arm is provided in place of the blade 3, comprising 5 a relatively short length of spring steel 7 at the root followed by a length of stiffer stainless steel 8. In this example the flexure of the arm is concentrated at the root where the spring steel 7 can be covered with thicker piezoelectric elements 9 than the patches 5. 10 Although the devices of Figures 1 to 3 are shown with the axes of both the pipe 2 and body 1 extending horizontally these devices can in principle be used in any other angular or rotational orientation, so long as the body 1 is generally crosswise to, and its cantilever arm is generally parallel to, the incident fluid flow. Electrical leads (not shown) extend from the coils 14 to an external circuit from which an associated battery or capacitor can be charged for powering downhole instrumentation or other electrical equipment.
Dolor De Cabeza
Various kinds of equipment and instrumentation requiring electrical power are typically placed downhole in oil and gas wells, such as pumps, valves, actuators, flowmeters, strain gauges, temperature and pressure monitors, data loggers, telemetry transceivers and so on. It is also 25 desirable in some circumstances that the bore of downhole pipes is left unobstructed to permit the passage of tools or instrumentation through the system.
Dolor De Hombro
This variant avoids the separate annular passage 26 which might present a risk of clogging in particularly contaminated flows. An example of both of these measures is shown in Figure 12. In this example there is a pipe 2 with a fixed mount 4 from which two cantilever arms 27 and 28 extend in opposite directions and carry respective bodies 29 and 30. Each body 29,30 is of 20 tapered diameter and effectively comprises two frustoconical surfaces extending to either side of a central maximum-diameter portion. It follows that a frequency equivalent to the particular natural frequency of the respective body/support system can be included in the trails produced by the interaction of that body with a range of different flow velocities.