RU2787446C1 - Downhole vane pump - Google Patents

Abstract

FIELD: petroleum engineering.

SUBSTANCE: invention relates to petroleum engineering and can be used in the design of radial bearing supports of multistage vane pumps. A downhole vane pump is proposed, which consists of a base and a head connected by a housing. A shaft and working bodies are installed inside in bearing supports. Each bearing support is a plain bearing, consisting of a fixed bushing with a bushing installed inside it with a radial clearance and fixed on the shaft. A wavy groove is made on the outer cylindrical surface of the bushing, into which a polymeric ring with elastic properties is installed, pressed by the inner cylindrical surface of the liner. At least one additional groove is made on the outer cylindrical surface of the bushing, which ensures the passage of liquid through the bearing under the polymeric ring with elastic properties.

EFFECT: ensuring reliable operation and increasing the resource of the radial plain bearing of a downhole vane pump when pumping a liquid containing mechanical impurities, reducing the shaft precession in the bearings and vibration.

10 cl, 7 dwg

Description

The invention relates to petroleum engineering and can be used in the design of radial bearing supports of multistage vane pumps.

Known downhole centrifugal pump having an appropriate system of radial bearings. Compatible radial bearings in accordance with the present invention use a fluid chamber of varying size between the stationary bearing housing and the bore in which it is installed. These variable fluid chambers may be formed by elastomeric elements, such as O-rings, which are mounted on the outside of the bearing housing. The size of the variable fluid chamber and the fluid it contains serve to dampen vibration and mechanical shock to the bearing components. Such damping of vibration and shock facilitates the use of ceramic components in the bearing system (according to the patent US5209577, class F16C 53/10, publ. 11.05.93).

The disadvantage of this solution is the presence of a gap in the bearing between the sleeve mounted on the shaft and the bearing housing. Under the action of unbalanced masses of the rotors, the shaft precession in the supports and vibration occurs. Elastomeric elements in radial bearings only partially dampen these oscillations, but do not reduce the precession and amplitude of oscillations. That is, this technical solution is aimed at combating the consequence, and not the cause of the oscillations.

Known pump containing a housing, a shaft, impellers, protective bushings, packages of sealing rings made of elastically deformable material, the cross section of which is a hollow truncated cone, according to the utility model, is equipped with bottom boxes. Moreover, the sealing elastically deformable rings of the packages together with the shaft form plain bearings, while on the inner cylindrical surface of the sealing rings, in addition to the extreme ones, at least three semicircular grooves are made. All sealing rings, except for the outer ones, are interconnected by a pin, and the outer sealing rings of the packages are made of elastic rubber-like wear-resistant material and are shaft seals (according to patent RU73410, class F04D 13/06, publ. 20.05.08).

The disadvantage of the bearings used in the pump is the large contact area of the outer rings and the package of rings with a protective sleeve, which increases friction, makes lubrication and heat removal difficult.

Known bearing, which contains a shaft and a housing with lubrication holes and evenly spaced around the circumference between the shaft and the housing pockets, sealed around the perimeter of elastic seals. In order to ensure self-centering and increase efficiency, elastic pocket seals are made with thickenings at the junction of axial and circumferential elements and are installed in the grooves of the shaft (according to patent SU1064063, class F16C 32/06, publ. 12/30/83).

The disadvantage of this solution is the difficulty of accurately manufacturing the groove on the shaft and the elastic seal. In addition, the elastic element is installed without pre-compression with a large gap between the housing and the shaft, so the self-centering of the bearing is highly dependent on the tightness of the pockets formed by the elastic element between the housing and the shaft. If the element is damaged, for example, during installation or wear products during operation, a radial runout of the shaft appears, which will adversely affect the performance and service life of the product in which this bearing is used.

The closest technical solution is a method of perceiving a radial load during rotation, which consists in installing at least one polymer wave-like ring between coaxial cylindrical surfaces that perform rotational movement relative to each other and a common axis. In this case, the ring is in an elastically compressed state relative to the cylindrical surfaces. A sliding bearing is also proposed, in which this method is implemented. The bearing consists of a housing and a bushing, between the coaxial cylindrical surfaces of which at least one polymer wave-like ring is installed. In this case, the ring is in an elastically compressed state relative to cylindrical surfaces (according to the patent RU2763763, class F16C 17/02, F16C 27/06, publ. 10.01.22).

The disadvantage of this solution is that during operation of such a bearing, for example, as part of a submersible vane pump, the mechanical impurities contained in the medium pumped by the pump (sand, wear particles, proppant, etc.) will accumulate in the gap between the sleeve and the bearing housing behind ring. This will lead to increased wear of the bearing, as well as to its heating and destruction.

The technical result to which the present invention is directed is to ensure reliable operation and increase the resource of the radial plain bearing of a downhole vane pump when pumping a liquid containing mechanical impurities, reducing the shaft precession in the bearings and vibration.

The specified technical result is achieved by the fact that the borehole vane pump consists of a base and a head connected by a housing, a shaft and working bodies are installed inside the bearing supports, each bearing support is a sliding bearing, consisting of a fixed liner with a radial clearance installed inside it and fixed on the shaft by a bushing, on the outer cylindrical surface of the bushing there is a wavy groove, in which a polymeric ring with elastic properties is installed, pressed by the inner cylindrical surface of the bushing, and differs in that at least one additional groove is made on the outer cylindrical surface of the bushing, ensuring the passage liquids through the bearing under the polymer ring with elastic properties.

In addition, each additional groove can be made at an angle to the bearing axis.

In addition, on the outer cylindrical surface of the sleeve, a groove can be made along the circumference, the depth of which exceeds the depth of the wavy groove.

In addition, on the outer cylindrical surface of the sleeve at the intersection of the wavy groove and additional grooves, blind holes can be made, the depth of which exceeds the depth of the wavy groove.

In addition, the length of the sleeve may be less than the length of the liner;

In addition, the insert can be made of a material with a hardness of at least 55 HRC, such as hardened steel, carbide, ceramic, carbula.

The present invention is illustrated by the following drawings:

Fig. 1 - borehole vane pump;

Fig. 2 - plain bearing;

Fig. 3 - plain bearing in a disassembled state;

Fig. 4 - bearing sleeve with circumferential groove;

Fig. 5 - bearing sleeve with blind holes;

Fig. 6 - plain bearing, in which the length of the sleeve is less than the length of the liner;

Fig. 7 - an example of the implementation of the sleeve.

A downhole vane pump (Fig. 1) consists of a base 1 and a head 2 connected by a housing 3. Inside, a shaft 5 and working bodies are installed in the bearing supports 4, which are sequentially installed impellers 6 mounted on the shaft 5, and guide vanes 7, installed in box 3.

Each bearing support 4 is a radial plain bearing (Fig. 2), consisting of an insert 8 and a bushing 9 installed inside it with a radial clearance. A keyway 10 is made in the hole of the bushing 9 for fastening to the shaft 5.

On the outer cylindrical surface of the sleeve 9 (Fig. 3) made a wave-like groove 11, which is installed polymer ring 12 with elastic properties. On the outer surface of the sleeve, additional grooves 13 are made at an angle to the bearing axis, which ensure the passage of fluid through the bearing under the polymer ring due to the fact that the depth of the additional grooves 13 is greater than the depth of the wavy groove 11.

For greater strength of the sleeve 9 and to ensure the passage of fluid under the ring on the outer surface of the sleeve 9, a groove 14 (Fig. 4) can be made around the circumference, the depth of which exceeds the depth of the wavy groove 11. For the same purpose, on the outer cylindrical surface of the sleeve 9 at the intersection wavy groove 11 and additional grooves 13 can be made blind holes 15 (Fig. 5), the depth of which exceeds the depth of the wavy groove.

To ensure better leaching of mechanical impurities and cooling the bearing, the length L _{1 of} the sleeve 9 (Fig. 6) should be less than the length L _{2 of} the liner 8. This will increase the fluid velocity at the outlet of the sleeve.

Application.

A downhole vane pump is used to produce reservoir fluid from a well as part of a submersible unit, which also includes a submersible electric motor (SEM), hydraulic protection and various upstream devices. The SEM is powered by a cable. The SEM transmits torque to the pump shaft 5 and impellers 6, which provide the creation of pressure. Guide vanes 7 direct the flow to the input of impellers 6.

Bearing supports 4 operate in a reservoir fluid containing mechanical impurities, sand, proppant, and chemically aggressive compounds. The use of a polymer ring 12 with elastic properties, installed on the sleeve to absorb the radial load during rotation in the bearing support 4 as one of its elements, increases the reliability of operation and service life due to the properties of the polymer material, which has high hardness, elasticity and wear resistance. As a result, wear, shaft precession and vibration are reduced.

The presence of additional grooves 13 ensure the pumping of liquid through the radial bearings, washing out mechanical impurities from the gap between the bushing 9 and the bushing 8, and thereby reduce wear and promote cooling. For greater efficiency of this process, it is advisable that the sleeve has a shorter length than the liner 8. This allows you to increase the speed of the fluid passing through the bearing, and, as a result, contributes to better washing out of mechanical impurities and cooling.

For better pumping of fluid through the bearing, additional grooves 13 should be made at an angle to the bearing axis. The condition for allowing liquid to be pumped through the bearing is that the depth of the additional grooves 13 must be greater than the depth of the wavy groove 11 so that the liquid can pass under the polymer ring 12. In addition, for better passage of liquid under the polymer ring, the sleeve 9 can be made circumferential groove 14, the depth of which exceeds the depth of the undulating groove 11, or blind holes 15, the depth of which must also exceed the depth of the undulating groove. In this case, additional grooves 13 can be made smaller or the same depth as the wavy groove 11, which will positively affect the strength of the sleeve 9.

The execution of the liner 8 of a material having a hardness of at least 55 HRC, allows you to increase its wear resistance when working with a constant removal of mechanical impurities. Hardened steels, hard alloy, ceramics or carbool, which also have high temperature resistance, can be used as such material.

Thus, the solutions used in the invention provide reliable operation and increase the service life of the radial plain bearing of a downhole vane pump under conditions of removal of mechanical impurities, reduce shaft precession in the bearings and vibration, and thereby ensure the achievement of a technical result.

Claims (10)

1. Downhole vane pump, consisting of a base and a head connected by a housing, a shaft and working bodies are installed inside the bearing supports, each bearing support is a plain bearing, consisting of a fixed liner with a bushing installed inside it with a radial clearance and fixed on the shaft, a wavy groove is made on the outer cylindrical surface of the bushing, in which a polymeric ring with elastic properties is installed, pressed by the inner cylindrical surface of the liner, and characterized in that at least one additional groove is made on the outer cylindrical surface of the bushing, which ensures the passage of fluid through the bearing under the polymeric ring with elastic properties. 2. The pump according to claim 1, characterized in that each additional groove is made at an angle to the bearing axis. 3. The pump according to claim 1 or 2, characterized in that on the outer cylindrical surface of the sleeve, a groove is made around the circumference, the depth of which exceeds the depth of the wavy groove. 4. The pump according to claim 1 or 2, characterized in that blind holes are made on the outer cylindrical surface of the sleeve at the intersection of the wavy groove and additional grooves, the depth of which exceeds the depth of the wavy groove. 5. The pump according to claim 1 or 2, characterized in that the length of the sleeve is less than the length of the liner. 6. The pump according to claim 1 or 2, characterized in that the liner is made of a material with a hardness of at least 55 HRC. 7. The pump according to claim 6, characterized in that the liner material is hardened steel. 8. The pump according to claim 6, characterized in that the liner material is hard alloy. 9. The pump according to claim 6, characterized in that the liner material is ceramic. 10 The pump according to claim 6, characterized in that the material of the liner is karbul.

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