Radial thrust plain bearing on idle shaft extension of vetockhin induction motor for oil-and-gas wells

FIELD: machine building.

SUBSTANCE: downhole induction motor shaft idle extension supports radial thrust plain bearing to make rotor aligned with stator bore and keep working clearance between rotor and stator invariable. Proposed induction motor comprises housing 1, end shield 4, shaft 6 with idle extension provided with moving thrust sleeve 8 that has thrust sliding surface 9 radial sliding surface 10. Fixed bearing insert 11 made from high-density powder material and having similar sliding surfaces 9 and 10 is tightly fitted in cylindrical recess of said bearing shield. Sliding pairs are cooled down via free clearance 12 and bearing shield holes 13. Cooling water is fed outside via holes 14 and 15 in housing 1.

EFFECT: improved operating performances of downhole motor, higher reliability and efficiency.

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The invention relates to the field of electrical engineering, in particular to a submersible electric machines, which are used for drives of various underwater mechanisms drilling and production units in the development and production of minerals and mineral resources of oil and gas on the seabed, as well as for drives borehole pumps and drilling mechanisms in the exploration and commercial development of the marine continental shelf for oil and gas.

Known electric machine open design for operation in sea water at any depth with active cooling of the internal parts outboard marine water (see "Electrical machine Vetohina EMW", patent No. 2072609, B. I. No. 3, 27.01.97), which has a stator, a rotor with a shaft and bearings, enclosed in a leaky casing filled with liquid coolant, and bearing shields with holes. As the cooler used sea water, and the holes in the bearing shields for cold entrance and exit of heated water are the two groups. As the bearings in the specified machine uses ball bearing type U1 and U from corrosion-resistant stainless steel. The disadvantages of these bearings are: small resource in seawater (500-700 hours)are not designed for vertical machines.

From the local closest to declare, chosen for the prototype is an electric machine Vetohina EMW (see "Electrical machine Vetohina EMW", patent No. 1833703, USSR. 1989). This machine has a journal-thrust bearings for electrical machines of the type EMW liners which are made of high density anti-friction powder material (ceramic), and the movable sleeve is made of high-strength, corrosion-resistant, heat-treated stainless steel DI-VD mounted on the free ends of the shaft. This machine ensures the reliable operation of the drive any underwater mechanism in an infinite depth of immersion in sea water when all the rolls and trim. The disadvantage of this design EMW for netsquared is co measurement of the diameter and length of the rotor of the big sizes in large machines with large capacity, and bearings with movable bushings structurally impossible to perform in a submersible electric motors for pumps and mechanisms "Boers" for oil and gas wells with small diameter. Submersible motors for oil and gas wells have a small diameter to 150 mm, and the length of the large capacity of the engine reach 8 m, with the protector up to 16 m, in which the stators, the rotors and the protector are multistage. In addition, when the drilling depth up to 3000 m temp the temperature of the surrounding acidic aggressive formation water reaches 150°C, and when drilling at this depth is the deviation of the axis of drilling up to 80°, so the bearings should be compact, heavy duty and is resistant to corrosive water reservoir under these conditions, and to work reliably long on the slopes.

The objective of the invention is to improve the reliability, maintainability, durability and energy characteristics of the developed asynchronous machine (CA NGS) vertical shaft up to the pumps, the shaft down to the mechanism of "Drilling" on the immersion depth up to 3000 m and the temperature of the reservoir water up to 150°C in case of deviation from the vertical axis of the machine up to 80° through the use of heavily loaded bearing from the non-driving end of the shaft with a liner of high-density anti-friction powder material, ensuring the alignment of the rotor with the bore of the stator.

This goal is achieved by the fact that in the known asynchronous submersible electric machine vertical to the drive shaft up or down, containing a multipackage the stator and ventkanalami the rotor monolithic shaft, bearings, potecting protection active parts in the form of rings and bushings aluminum-magnesium-zinc alloy, enclosed in a housing with openings for entry and exit preservation of produced water for cooling, on the non-drive to the goals of the shaft is made hard-block bearing, consisting of a bearing shield inserted under locks into the housing and secured symmetrically positioned relative to each other by screws with countersunk on the outer side of the casing, a cylindrical bearing recess of the shield is pressed wtogua bearing shell of high-density anti-friction powder material (ceramic), which is the stationary part of the bearing and having a thrust and bearing sliding surface, and at the end of the shaft is pressed by a hot planting resistant glass bead of high-strength corrosion-resistant heat-treated stainless steel with hard and sliding support surfaces polished to 7-10 class finish, while cooling is Ambidextrous with water from the external environment through the symmetrical holes in the case, and directly on the sliding pair water flows through concentric holes in the bearing shield and gaps between the shaft and bearing shield.

The invention is illustrated by drawings, in which:

- figure 1 - bearing unit from the non-drive shaft end;

- in figure 2. - liner-thrust sliding bearing from the non-driving end of the shaft.

1 shows a bearing unit from the non-driving end of the shaft, which contains corpus, closed the lid 2, mounted symmetrically placed 3 screws with countersunk on the outer side of the housing. In the housing 1 is inserted under the locks bearing shield 4, fixed on the outer side symmetrically positioned relative to each other (6÷10) screws 5 with thread M 6 and potiki head. At the end of the shaft 6 hot pressed planting resistant glass 7 from heat-treated stainless steel 20X13, which has a shoulder 8 with the thrust sliding surface 9 and the reference radial sliding surface 10. In the bearing cylindrical recess pressed wtogua the liner 11 of the high-density anti-friction powder material, which is fixed to the moving part of the bearing, which also has thrust (axial) 9 and the bearing (radial) 10 sliding surfaces. Moving the thrust surface 9 and reference surface 10 of the thrust Cup 7 have after heat treatment (7÷10) class precision grinding, and the same sliding surfaces of the liner are rough processing class, not polished after machining on a lathe. The liner 11 (figure 1, figure 2) is made of a powder material with the chemical composition BRGM and after hot forming and calibration shall be specific load of 120 kgf/cm²in axial and radial directions at temperatures up to 300°, so work is Azor a sliding pair in the horizontal and vertical directions should be running 60÷80 MK for shaft diameter up to 60 mm For cooling the moving pairs free gap 12 between the bearing shield 4 and the thrust Cup 7 and through holes 13 in the bearing shield, through which the produced water flows from the cavity of the machine. In the cavity of the machine produced water enters through concentric orifices 14 in the casing and through the openings 15 into the heated water is partially released into the environment, and also presumably partly comes from the environment fresh cold water. The circumference of the holes 14 and 15 are evenly placed at an angle β relative to each other, the holes of one group 14 relative to the other 15 are shifted by the angle β/2 with the aim of improving the water and to maintain the mechanical strength of the casing. Choose 6 holes in each group with a diameter of 5 mm each. To improve cooling of the sliding pair and removal of the particulate insert has an axial groove 16 on the support surface and the slots 17 on a hard surface, as a continuation of the grooves 2. The geometric dimensions of the grooves on the diameter of 5-6 mm, the configuration of the cross section is a semicircle.

For protection against electrochemical contact corrosion of the bearing unit and the shaft on the shaft 6 is pressed wtogua protective sleeve 18 made of magnesium alloy grades ML with tight electrical contact with resistant glass 7 and the shaft 6, and to protect the hull inside e is about at the end of the pressed ring 19 of the same alloy.

Work CA NGS as follows. When the engine is operating as a pump drive shaft end up mechanical load from the weight of the rotor and the pump and stops the pump will be partially perceived resistant sliding surface 9 of the insert 11 after the establishment of a resource angular thrust bearing drive end. In case of any deviations of the rotor shaft from the vertical mechanical load will perceive bearing surface 10 of the insert 11. As the liner of the powder material has a high specific mechanical load (see above), then any deviation of the rotor from the vertical will not affect the alignment machine will not increase the working gap between the stator and the rotor, in the end, energy performance and efficiency of the engine will remain unchanged. When the engine is in drive "Bura" shaft down thrust load perceives angular thrust bearing drive end of the shaft, this bearing this burden does not perceive. When the deviation of the rotor shaft from the vertical, the process of maintaining alignment of the rotor and stator and hold the entire structure of the engine when the initial state is ensured in both cases, supporting the sliding surface 10.

The proposed technical solution will allow with high reliability to operate the motor armature NGS as Pref is Yes pump and the drilling mechanism in oil and gas wells in case of any deviations of the rotor shaft from the vertical axis. Supporting the sliding surface of the liner will ensure the alignment of the rotor with respect to the bore of the stator and the permanence of the working gap between the stator and the rotor, in the end, will provide a constant energy performance and engine efficiency, increase reliability and service life.

Asynchronous machine CA NGS vertical performance with a drive end of the shaft up or down, containing a multipackage the stator and ventkanalami the rotor monolithic shaft, bearings, cathodic protection active parts in the form of bushings and rings from aluminum-magnesium-zinc alloy that is enclosed in a housing with openings for inlet and outlet of the surrounding formation water for cooling, characterized in that on the non-drive end of the shaft is made-thrust sliding bearing consisting of a bearing shield inserted under locks into the housing and secured symmetrically positioned relative to each other by screws with countersunk on the outer side of the housing with in the cylindrical recess of the bearing shield pressed wtogua bearing shell of high-density anti-friction powder material (ceramic), which is the stationary part of the bearing and having a support and thrust sliding surfaces, and at the end of the shaft is pressed by a hot planting resistant glass bead of high strength is corrosion of heat-treated stainless steel and thrust sliding surfaces, polished up to 7-10 class finish, while cooling is Ambidextrous with the abstraction of water from the external environment through the symmetrical holes in the case, and directly on the sliding pair water flows through concentric holes in the bearing shield and gaps between the shaft and the bearing shield.