RU2310071C2 - Lubrication system for telemetering system power supply generator - Google Patents

Abstract

FIELD: survey of boreholes or wells, particularly electric machines adapted to supply power to well logging apparatus of telemetering systems, which controls parameters during well drilling and are adapted for information transmission during oil and gas well drilling.

SUBSTANCE: lubrication system comprises filling device, cavity defined between outer rotor and stator and filled with liquid lubricant, as well as pressure and thermal liquid lubricant expansion compensator of piston-type. The compensator is arranged in upper generator side and connected to generator rotor connected to lower cowl from another side thereof. End seal is installed in the lower cowl. Liquid lubricant may be discharged into environment by releasing movable spring-loaded part of end seal. Summary force of springs pressing movable end seal part to fixed one exceeds that created at movable end seal part by liquid lubricant pressure caused by compensator spring action on pressure compensator piston and by generator turbine pressure difference. Fixed end seal part has shoulder abutting against end of inner bearing ring and is sealingly retained by generator stator axis. Movable end seal part may slide in axial direction in lower cowl of the generator, is sealed with respect to inner surface thereof and is spring-loaded relatively ring. Pins are installed on outer ring surface. Pins are inserted in slots made in lower cowl end. Movable end seal part also has slots adapted to receive positioning screws to limit movable part travel and to prevent spring falling out. The positioning screws are located in threaded orifices made in ring side.

EFFECT: increased generator reliability and service life, decreased maintenance costs and improved reliability of generator air-tightness after generator flushing with liquid lubricant.

5 cl, 7 dwg

Description

The invention relates to electric machines designed to power downhole equipment of telemetric systems for controlling downhole parameters, designed for information support of drilling oil and gas wells.

A device for lubricating a turbogenerator of an autonomous downhole assembly according to AS No. 1059339 is known. A device for lubricating a turbogenerator of an autonomous well assembly comprises a lubricator located in the hollow shaft of the turbogenerator rotor, including a spring-loaded piston and a dispensing channel in communication with the over-piston space of the shaft cavity, and a filler neck. The device for improving operational reliability is equipped with a sleeve located in the shaft cavity and mounted on it, a hollow signal rod concentrically mounted in the sleeve with axial movement, interacting with the piston and spring-loaded relative to the sleeve, and a check valve located at the mouth outlet and fixed together with it at the end of the rod remote from the piston, and the dispensing channel is made in the shaft wall. The disadvantage of the lubrication system is the inability to flush the generator with lubricating fluid without disassembling the generator.

A known lubrication system of an autonomous turbine generator according to the patent of the Russian Federation No. 20541. The lubrication system of an autonomous turbine generator contains seals, a compensator for the thermal expansion of the lubricating fluid, made in the form of a piston, at the end of which there is a retractable rod indicator with a graduation applied, corresponding to the remaining and consumed lubricating fluid. A spring is installed between the end of the cup and the piston. The cavity between the end of the glass and the piston is in communication with the working medium. The piston is hollow. The disadvantage of the lubrication system is the inability to flush the generator with lubricating fluid with oil change without disassembling the generator.

A known lubrication system of the power generator of the telemetry system according to the patent of the Russian Federation for the invention No. 2239699, 10.11.2004 (prototype). The lubrication system of the downhole equipment generator contains a filling device at its front end, a cavity between the external rotor and the stator, filled with lubricating fluid, a pressure compensator and thermal expansion of the lubricating fluid. The compensator for pressure and thermal expansion of the lubricating fluid is placed on the side of the device for mounting the generator and is made in the form of a piston mounted inside the rotor with the possibility of axial movement, and a seal installed in turn inside the piston with the possibility of axial movement with it. The piston is made with the possibility of drainage of the lubricating fluid when fully charged into the environment through the gap between the rotor and the piston. The possibility of draining the lubricating fluid into the environment is ensured by a stepped groove inside the rotor opposite the piston at its extreme position, corresponding to a complete filling of the lubricating fluid.

The cavity between the external rotor and the stator communicates with the environment through channels and / or holes made in the piston or in the external rotor.

The disadvantage of the prototype is:

1. The small volume of the pressure compensator caused by the presence of a central axis, which reduces the volume of the compensator by half at the same length.

2. The piston is ring-shaped, since not only the total perimeter increases, which requires compaction, but also the possibility of jamming increases, which leads to a decrease in pressure inside the generator and the ingress of drilling fluid.

3. The lack of alignment of the piston of the pressure compensator and the thermal expansion of the lubricating fluid when it enters the stepped groove inside the rotor, which leads to a distortion of the piston and, as a result, depressurization of the generator, failure of the bearings and generator failure. One of the reasons for distortion of the piston may also be the ingress of large particles of drilling fluid between the compensator piston and the stepped groove.

4. Low reliability associated with blockage of channels made in the piston or in the external rotor by components of the drilling fluid, which leads to an increase in the time of maintenance or makes it impossible to further use the generator without replacing failed parts.

The objectives of the invention are: to increase the reliability of the generator, increase its service life, reduce maintenance costs, as well as increase the reliability of the seal of the generator after washing it with a lubricating fluid.

The solution to these problems was achieved due to the fact that the lubrication system of the power generator of the telemetry system, containing a filling device, a cavity between the rotor and the stator of the generator, filled with lubricating fluid, a pressure compensator and thermal expansion of the lubricating fluid, made in the form of a spring-loaded piston. The compensator for pressure and thermal expansion of the lubricating fluid is located in the upper part of the generator and is combined with the rotor of the generator, which on the other hand is connected to the lower fairing. An end seal is installed in the lower fairing, consisting of a fixed part fixed on the axis of the stator of the generator and a spring-loaded movable part installed in the lower fairing with the possibility of pressing to ensure drainage of the lubricating fluid into the environment. Moreover, the inner surface of the fairing, in which the moving part of the mechanical seal is placed, is made smooth without changing the diameter. Moreover, the total force of the springs, pressing the moving part of the mechanical seal to the stationary one, is higher than the load that is created on the moving part of the mechanical seal by the pressure of the generator lubricating fluid caused by the action of the compensator spring on the piston of the pressure compensator, and the pressure drop across the generator turbine. The fixed part of the mechanical seal is made with a shoulder abutting against the end face of the inner ring of the bearing, fixed and sealed on the axis of the generator stator. The movable part of the mechanical seal is installed with the possibility of axial movement in the lower cowl of the generator and is sealed relative to its inner surface and spring-loaded relative to the ring, on the outer surface of which there are pins included in the grooves made on the end of the lower cowl of the generator. Grooves are made on the movable part of the mechanical seal, in which, to limit the stroke and prevent the spring from falling out, set screws are located in the threaded holes made on the side surface of the ring.

The proposed technical solution has novelty, industrial applicability and inventive step, which is confirmed by patent research, and the fact that it does not explicitly follow from the prior art for a specialist.

The invention is illustrated in the drawings of figures 1 ... 5, where:

Figure 1 shows the generator before filling with lubricating fluid.

Figure 2 shows the generator during refueling.

Figure 3 shows an enlarged lower fairing, with mechanical seal.

Figure 4 shows an enlarged lower fairing with mechanical seal, with the movable spring-loaded part of the mechanical seal. The arrows show the path of the lubricating fluid with a further increase in pressure in the internal cavity of the generator during its drainage.

Figure 5 shows the movable part of the mechanical seal.

Figure 6 shows a section aa the movable part of the mechanical seal.

Figure 7 shows the individual parts of the movable part of the mechanical seal.

The generator (Fig. 1) contains a device for mounting the generator 1, an external rotor 2 with a turbine 3. An external rotor 2 with magnets 4 mounted on it is mounted through bearings 5 and 6 on the stator 7. The stator 7 is made with an axis 8 and an electrically-wrapped sealant 9 The lubrication system of the power generator of the telemetric system includes a filling device 10, consisting of a plug 11 with a seal 12, a valve seat 13 and a ball 14 acting as a valve, pressed against the valve seat 13 by the valve spring 15. The cavity between the external rotor 2 and the stator 7 is filled cm sedating fluid. The compensator for pressure and thermal expansion of the lubricating fluid 16 is made in the form of a piston 17 and cylinder 18. To prevent drilling fluid from getting inside the generator by creating a pressure inside the generator above the ambient pressure, the piston 17 is spring-loaded with a pressure compensator 19. The compensator for pressure and thermal expansion of the lubricant 16 is located in the upper part of the generator and is combined with the rotor 2 of the generator, which on the other hand is connected to the lower fairing 20, in which the end face is installed howling seal 21. The end seal 21 consists of a stationary part 22 and the movable springs 23, spring-loaded face seal 24 relative to the ring 25. The friction surface 26 of the end seal 21 are provided in the form of carbide rings. The possibility of draining the lubricating fluid into the environment is ensured by squeezing the movable spring-loaded part of the mechanical seal 23. Moreover, the total force of the springs 24 pressing the movable part of the mechanical seal 23 to the stationary 22 is higher than the load that is created on the moving part of the mechanical seal 23 by the pressure of the generator lubricating fluid, caused by the action of the spring of the compensator 19 on the piston of the pressure compensator 17, and the pressure drop across the generator turbine 3. The stationary part of the mechanical seal 22 is made with a shoulder 27 abutting against the end of the inner ring of the bearing 6. It is fixed by screws 28 and sealed on the axis of the stator of the generator 8 by the sealing ring 29. The movable part of the mechanical seal 23 is mounted with axial movement in the lower cowl 20 of the generator, sealed relative to its inner surface by a sealing ring 30 and spring-loaded relative to the ring 25, on the outer surface of which there are pins 31 included in the grooves 32 made on the end e of the lower fairing 20 of the generator. On the movable part of the mechanical seal 23, grooves 33 are made, in which, to limit the stroke and prevent the spring of the mechanical seal from falling out 24, set screws 34 are located in threaded holes made on the side surface of the ring 25.

The device operates as follows. Before refueling the generator (Fig. 1), turn off the plug 11 with a seal 12, attach the oil pump. The generator is turned down by the turbine and the lubricant is pumped. In this case, the spring 19 is compressed, the piston 17 of the pressure compensator and the thermal expansion of the lubricating fluid 16 moves all the way, and the lubricating fluid fills the entire volume of the cylinder 18. With a further increase in pressure, an axial load is created on the movable part of the mechanical seal 23, compressing the springs of the mechanical seal 24. Between movable 23 and stationary 22 parts of the mechanical seal 21, a gap is formed in which the air enters. Generator refueling is judged by the absence of bubbles in the resulting grease. After filling the generator, disconnect the oil pump and wrap the plug 11 with gasket 12. The generator, ready for operation, is attached using the device for attaching the generator 1 to the telemetry system and through the generator casing to the drill pipe string. The telemetry system and the generator casing are not shown in FIGS. 1 ... 7.

During drilling, mud pumps are put into operation. The drilling fluid acts on the blades of the turbine 3 and rotates the external rotor 2 with magnets 4 mounted on it. An EMF appears in the electrically wound 9, which is part of the stator 7 and is sealed. Together with the external rotor 2, the compensator for pressure and thermal expansion of the lubricating fluid 16 rotates, as well as the lower cowl 20, in which the movable part of the mechanical seal 23 is installed. The springs of the mechanical seal 24 press against the friction surfaces 26 of the movable and stationary parts of the mechanical seal 21 relative to the ring 25, which fixed from rotation by pins 31 in the grooves 32 made on the end of the lower cowl 20. The grooves 33 made on the moving part of the mechanical seal 23 and the set screws 34 included therein, about espechivayut rotation of the movable part of the mechanical seal 23 together with the outer rotor 2 and the lower radome 20, as well as axial movement during wear of friction surfaces 26, filling or flushing the generator lubricating fluid. On the piston 17 of the pressure compensator 16, a load occurs, which is created by the action of the spring of the pressure compensator 19 and the pressure drop on the turbine of the generator 3, which provides excess pressure inside the generator. Higher pressure inside the generator provides lubrication of the friction surfaces of the mechanical seal 21, made in the form of carbide rings 26, during operation and prevents the penetration of the drilling fluid into the generator. In this case, the supply of lubricating fluid in the cylinder 18 gradually decreases, on the volume of which the life of the generator largely depends.

After lifting the drill pipe string, the oil pump is again connected to the generator and, without disassembling it, washing is carried out from the ingested drilling fluid while changing the lubricant. A pressure is generated in the generator, which first compresses the spring of the pressure compensator 19, and the cylinder 18 is completely filled with lubricating fluid, after which the springs of the mechanical seal 24 are compressed and the movable part of the mechanical seal 23 moves away from the stationary 22. The inner surface of the fairing 20, in which the sealed ring 30, the movable part of the mechanical seal 23, is made smooth without changing the diameter, which creates a good direction and prevents jamming of the movable part of the mechanical seal 23 when returning it back by springs 24. A lubricating fluid is pumped through the resulting gap. After turning off the oil pump, the pressure in the generator decreases, and the springs of the mechanical seal 24 return the movable part of the mechanical seal 23 to the stop of the carbide rings 26. In this case, the tightness of the generator is restored with a fully charged pressure compensator and thermal expansion of the lubricating fluid 16 and with an excess pressure provided by the compressed spring pressure compensator 19.

The application of the invention allowed:

1. Improve the reliability of the generator.

2. Increase the life of the generator.

3. Reduce maintenance time.

4. Reduce maintenance costs.

5. Ensure that the generator is flushed with lubricating fluid.

6. To ensure removal of the drilling fluid that has entered through the mechanical seal.

7. To increase the reliability of the generator seal after washing it with a lubricating fluid.

8. Significantly increase the volume of the pressure compensator and thermal expansion of the lubricating fluid.

9. Increase the service life of parts and o-rings of the pressure compensator.

Claims (5)

1. The lubrication system of the power generator of the telemetric system, comprising a filling device, a cavity between the rotor and the stator of the generator filled with lubricating fluid, a pressure compensator and thermal expansion of the lubricating fluid, made in the form of a spring-loaded piston, characterized in that the pressure compensator and thermal expansion of the lubricating fluid is located in the upper part of the generator and combined with the rotor of the generator, which on the other hand is connected to the lower fairing, in the lower fairing is installed a mechanical seal has been introduced, consisting of a fixed part fixed on the axis of the generator stator and a spring-loaded movable part installed in the lower cowl with the possibility of pressing to ensure drainage of the lubricating fluid into the environment, the inner surface of the cowl, in which the movable part of the mechanical seal is placed, is made smooth without changing the diameter. 2. The lubrication system of the power generator of the telemetry system according to claim 1, characterized in that the total force of the springs pressing the movable part of the mechanical seal to the stationary load is higher, which is created on the movable part of the mechanical seal by the pressure of the lubricating fluid of the generator caused by the action of the compensator spring on the compensator piston pressure and thermal expansion of the lubricant, and the pressure drop across the generator turbine. 3. The lubrication system of the power generator of the telemetric system according to claim 1, characterized in that the fixed part of the mechanical seal is made with a shoulder resting on the end face of the inner ring of the bearing, fixed and sealed on the axis of the stator of the generator, and the movable part of the mechanical seal is mounted with axial movement in the lower fairing of the generator and sealed relative to its inner surface. 4. The lubrication system of the power generator of the telemetric system according to claim 1 or 2, characterized in that the movable part of the mechanical seal is spring-loaded relative to the ring, on the outer surface of which there are pins included in the grooves made at the end of the lower fairing of the generator. 5. The lubrication system of the power generator of the telemetric system according to claim 1 or 2, characterized in that on the movable part of the mechanical seal grooves are made, in which, to limit the stroke and prevent the spring from falling out, set screws located in the threaded holes made on the side surface of the ring .

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