RU2400906C1 - Power supply generator of bottomhole telemetric system - Google Patents

Abstract

FIELD: electricity. ^ SUBSTANCE: power supply generator of telemetric system comprises device of mechanical energy conversion into electric one, for this purpose magnetic coupling is installed between rotor and device of mechanical energy conversion into electric one, and coupling includes master and slave half-couplings, and device of mechanical energy conversion into electric one is arranged in the form of electrostatic generator connected by shaft to slave half-coupling. Electrostatic generator is made in the form of group of disks from dielectric material, installed on shaft between metal disks, which comprises collecting brushes at both sides. Electrostatic generator is installed in sleeve of electric insulation material, which is installed inside protective body. Magnetic coupling is arranged as end and cylindrical, half-coupling is connected to rotor, and slave one - to shaft. Inner cavity of master coupling is filled with lubricating liquid via hole. ^ EFFECT: simplified design, increased reliability and capacity of generator with reduction of diametrical dimensions and weight of electric generator. ^ 4 cl, 1 dwg

Description

The invention relates to electric machines. Specifically, the invention is intended for a downhole power generator and a downhole telemetry system transmitter. The generator converts the energy of the flushing fluid into electrical energy, which is needed to power the downhole navigation and geophysical instruments during drilling and the transmitter of the electromagnetic communication channel. For the telemetry system to work at great depths, an increase in the power of the transmitting device to 1 kW or more is required. To get more power with small dimensions of the generator is very problematic

A self-contained turbine unit (electric generator) is also intended for supplying electric energy to the telemetry system, containing a hydroturbine driven by a washing fluid stream, an oil-filled stator filled with an epoxy compound, and a rotor of an alternating current generator with permanent magnets located on the same shaft with a hydraulic turbine. (Molchanov A.A., Siraev A.X. Borehole autonomous systems with magnetic recording, M., Nedra, 1979, pp. 102-103).

This generator consists of a stator located inside the unit and a six-pole annular magnetic rotor made from the outside. The rotor is also a casing for the working blades of a three-stage hydraulic turbine. In front of each stage of the working blades of the hydraulic turbine, in turn, there are three stages of guide vanes assembled on the outer casing, which increases the diameter of the device. To prevent the flushing fluid from entering the generator and the bearing units, sealing devices are installed, the internal cavity of the generator is filled with transformer oil.

Due to the fact that the generator operates in the temperature range from -40 to + 130 ° С, at drilling depths up to 3500 m and more, and the oil volume changes with temperature, a compensator for pressure and thermal expansion of the lubricating fluid (oil) is introduced. The compensator for pressure and thermal expansion of the lubricating fluid is made inside the inlet fairing of the generator. It consists of two thin profile plates, one of which is convex and the other is concave. The compensator for pressure and thermal expansion of the lubricating fluid is designed to compensate for changes in the volume of oil in the oil-filled cavity of the generator under operating conditions with increasing temperature, as well as equalizing the pressure inside and outside the generator.

The disadvantages of this generator are: low reliability, low resource, large dimensions and weight of the device, design complexity.

These shortcomings are due primarily to the fact that a multistage turbine with guide vanes is used as a drive. The use of a hydraulic turbine with guiding devices as a drive places high demands on the quality of cleaning the washing liquid from fractions of drill cuttings and foreign objects, the ingress of which into the gap between the working and guide vanes of the hydraulic turbine can lead to its stop (jamming). The presence of guiding devices of a hydraulic turbine increases the diametrical dimension of the electric generator, which is undesirable when drilling wells of relatively small diameter.

The second design flaw is the complexity and unreliability of the pressure compensator and thermal expansion of the lubricating fluid. Due to the elasticity of the walls of the compensator, the pressure of the lubricating fluid is always less than the pressure of the environment. This can result in flushing fluid entering the generator’s lubrication system and in the wear of bearings, seals and other parts.

Known electric generator according to the patent of the Russian Federation No. 2331149, prototype. This generator contains a protective housing, at least one attachment point, a rotor with a turbine and a device for converting mechanical energy into electrical energy,

The disadvantages of the generator are the unreliability and complexity of the design, due to the low reliability of the field windings, insufficient power of the generator with its limited diametrical dimensions.

The tasks of its creation are to simplify the design, increase power while reducing the diametrical dimensions and weight of the generator.

The solution to this problem was achieved due to the fact that in the power generator of the telemetry system containing a protective case, an electrical connector, at least one attachment point, a rotor with a turbine and a device for converting mechanical energy into electrical energy, is installed between the rotor and the device for converting mechanical energy into electrical energy a magnetic coupling containing a leading and a driven half-coupling, and a device for converting mechanical energy into electrical energy is made in the form of an electrostatic generator a torus connected by a shaft with a driven coupling half. The electrostatic generator is made in the form of a group of disks made of dielectric material mounted on a shaft between metal disks on which collector brushes are made on both sides. The electrostatic generator is installed in a glass of insulating material, which is installed inside the protective housing. The magnetic coupling is made face. The magnetic coupling is cylindrical.

Between the driven and leading half-couplings, a sealed partition is also made containing parts of magnetically permeable material, while the leading half-coupling is connected to the rotor, and the driven half to the shaft. The inner cavity of the drive clutch is filled with lubricant. The hole for filling the lubricating fluid of the cavity of the driving coupling half is made from above. The generator contains at least one pressure compensator and thermal expansion, communicating with the cavity of the leading coupling half.

The invention is illustrated in the drawing.

The downhole tool power generator is installed in the drill pipe string or in the casing (not shown) and contains a protective housing 1 and at least one fastener 2. In the fastener device 2 of the electric generator holes 3 are made for the passage of the drilling fluid.

The generator contains a rotor 4 with a turbine 5. The turbine 5 has obliquely mounted flat blades, at an angle of 20 ... 60 °.

The protective housing 1 has an electrical connector 6 at the bottom, to which wires 7 are connected from a device for converting mechanical energy to electrical 8. Between the rotor 4 and the device for converting mechanical energy into electrical 8, a magnetic coupling 9 is installed.

The magnetic coupling 9 contains a leading and a driven half-coupling 10 and 11 with permanent magnets 12 and a sealed partition 13 between them having magnetically permeable parts 14. In this case, two versions of the magnetic coupling 9 are possible: a mechanical coupling and a cylindrical coupling.

A device for converting mechanical energy into electrical energy 8 comprises an electrostatic generator connected through a shaft 16 to a driven coupling half 11.

The electrostatic generator 15 is made in the form of a group of disks made of dielectric material 17 mounted on a shaft 16 between metal disks 18 on which current collection brushes 19 are made on both sides. The electrostatic generator 15 is installed in a glass 20 of insulating material that is installed inside the protective housing 1. Shaft 16 is mounted on bearings 20 and 21. Bearings 20 and 21 are sealed with seals 22 and 23, respectively, or closed.

The cavity 24 of the driving coupling half 10 is isolated from the cavity 25 of the driven coupling half 11 by a sealed partition 13. The cavity 26 of the mechanical energy to electrical energy conversion device 8 is sealed with a seal 22 made in the partition 27. The cavities 25 and 26 are sealed and filled with inert gas.

To fill the cavity 24 of the driving coupling half 10 with lubricating fluid, an axial hole 28 is provided in the rotor 4 and plugged with a screw 29.

The rotor 4 is mounted on a bearing 30, which is protected by a seal (s) 31.

To compensate for the flow of lubricating fluid, thermal expansions and variable pressure in the well, at least one compensator for pressure and thermal expansion 32 is provided, made in front of the generator body 1. It is most advisable to make 2 ... 8 pressure compensators and thermal expansion 32 and place inside the protective housing 1 from the side of the hydraulic turbine 5, since only the cavity 24 needs compensation, and the cavities 25 and 26 are hermetic, can be filled with an inert gas and do not need compensation provided that the walls of the protective casing are of sufficient thickness.

Each compensator for pressure and thermal expansion 32 contains a compensation piston 33 mounted and sealed relative to the protective housing 1. The cavity 34 under the compensation piston 33 with the hole (s) 41 is connected to the cavity 24 of the driving coupling half 10, and the cavity 36 above the compensation piston 33 is connected with a hole (holes ) 37 with the environment to compensate for changes in pressure and thermal expansion of the lubricant. Compensation piston 33 is spring-loaded by spring 38 towards the leading coupling half 10 to create excess pressure in the cavity 24.

When the generator is operating, drilling fluid passes through a hydraulic turbine 5, which begins to rotate with the rotor 4 and the leading coupling half 10. Magnetic flux passes through the magnetically conducting parts 14 and drives the driven coupling half 11. The driven coupling half drives the shaft 16, which drives the package disks made of dielectric material 17. Current collectors 19 remove static electricity from these disks and transmit electric energy to electric connector 6 through metal disks 18 and wires 7.

When the volume of the lubricating fluid in the cavity 24 is changed for any reason, the compensation piston 33 moves accordingly. As a result, the pressure within the cavity 24 is always maintained at 2 ... 4 atm more than the ambient pressure. This prevents the abrasive particles contained in the drilling fluid from penetrating into the cavity 24. If several pressure compensators and thermal expansion 32 are used, then one of the holes 37 is clogged (or several holes 37, if 4 ... 8 pressure expansion and thermal expansion joints 32 are used) , the remaining pressure compensators and thermal expansion 32 will perform their function, even when one of them. This significantly increases the reliability of the generator and its resource. The application of the invention allowed to achieve the following.

1. To simplify the design of the generator, due to the rejection of the use of field windings and permanent magnets.

2. To increase the power and voltage at the electrical terminals of the generator through the use of an electrostatic generator capable of creating high voltage.

3. Significantly increase the service life of the bearing by reducing the diameter of the rotor to the minimum possible.

4. To reduce the imbalance of the rotor of the generator by reducing its diameter and length. Only a hydraulic turbine and a driven coupling half are fixed on the rotor.

5. To increase the reliability of the electric generator due to the complete sealing of its main cavities: the cavity of the driven coupling half and the electrostatic generator and due to the sealing of the cavity of the driving coupling half by the relatively small diameter of the rotor.

6. Improve maintainability of the generator.

Claims (4)

1. The power generator of the telemetry system, comprising a protective housing, an electrical connector, at least one attachment point with holes for drilling fluid passage, a rotor with a turbine and a device for converting mechanical energy into electrical energy, characterized in that between the rotor and the device for converting mechanical energy a magnetic coupling is installed in the electric one, made in the form of a follower connected to the shaft and a drive coupled to the rotor of the coupling halves with an airtight partition between them, containing magnetically permeable material, and as a device for converting mechanical energy into electrical energy, an electrostatic generator is installed on the shaft of the driven coupling half in the form of a group of disks made of dielectric material between metal disks on which current-collecting brushes are made on both sides and which are placed in a glass of insulating material inside the protective housing, while the inner cavity of the leading coupling half is filled with a lubricating fluid, and is installed in the upper part of the protective housing, p at least one compensator for pressure and thermal expansion in communication with the cavity of the driving coupling half. 2. The generator according to claim 1, characterized in that the magnetic coupling is made end. 3. The generator according to claim 1, characterized in that the magnetic coupling is cylindrical. 4. The generator according to any one of claims 1 to 3, characterized in that the hole for filling the lubricating fluid of the cavity of the leading coupling half is made from above.