RU2457366C2 - Downhole multistage modular rotary pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed pump comprises several identical modules 1 with their shafts coupled by splined bushes. Every module 1 has case 4 to house stages made up of impeller 4, guide vanes 5, head 6 and base 7. Case 3 houses radial intermediate plain bearings 8 with axial fluid passages. Every bearing 8 has housing 9 and two hard-alloy sleeves 10, 11. Sleeve 10 is fitted on shaft 2 while sleeve 11 is inserted in housing 9 of bearing 8 inserted in steel cage 12 arranged in case 3. Housings 9 of bearings 8 fitted in head 6 and/or base 7 of module 1 are unified with housing 9 of bearing 8 arranged in case 3 of module 1. Housings 9 of bearings 8 arranged in case 3, base 7 and head 6 of module 1 are unified.

EFFECT: ruled out slip or fall of hard-alloy sleeve, unification of intermediate bearings.

4 cl, 2 dwg

Description

The invention relates to techniques for the selection of liquid from wells, in particular to submersible centrifugal electric pump units designed for oil production from wells.

In the oil industry, in the designs of submersible centrifugal pumps, radial bearing housings with fluid channels are usually made of cast iron, the bearing housing has carbide bushings that form a slip pair.

The housing of the intermediate bearing, having channels of complex shape, is cast from niresist cast iron.

In particular, a multi-stage submersible centrifugal pump is known according to patent RU 2317445 (F04D 13/10, F04D 29/04, publ. 02/20/2008, patented. State educational institution of higher education "Tyumen Oil and Gas University"), which contains a number of similar modules -sections, each module-section has a housing in which packages of steps are installed, and a base that is screwed into the housing of the module-section, a removable radial plain bearing with axial channels for the passage of the pumped liquid is installed without a gap tee. A carbide sleeve is pressed into the radial bearing housing, forming a slip pair with a carbide sleeve mounted on the pump shaft.

The use of carbide bushings in plain bearings is complicated by differences in thermal expansion coefficients between niresist and hard alloys. The coefficient of thermal expansion of the niresist is higher than the coefficient of thermal expansion of the hard alloy, therefore, when heated, the tension between the bearing housing and the sleeve weakens.

Thus, a disadvantage of the known devices is that when the temperature rises, there is a chance of turning or falling out of the carbide sleeve from the bearing housing, which leads to wear of the bearing housing and failure of the pump. This circumstance reduces the operational reliability of the design of a submersible centrifugal pump.

The closest technical solution is the design of an electric centrifugal submersible pump, described by several researchers. The pump contains module sections, each module section has a housing in which stage packages are installed, and a base that is screwed into the module section housing, radial plain bearings with axial channels for fluid passage are installed in the head and base of the module section [Ivanovsky V .N., Darishchev V.I., Sabirov A.A., Kashtanov VS, Beijing S.S. Equipment for oil and gas production: at 2 o’clock. - M.: State Unitary Enterprise Oil and Gas Publishing House of the Russian State University of Oil and Gas. I.M. Gubkina, 2002 .-- 4.1. - S. 429-430; Ageev Sh.R., Grigoryan E.E., Makienko G.P. Russian installations of vane pumps for oil production and their application. - Perm: LLC “Master-press”, 2007. - P.105-106].

The disadvantage of this design along with the above is the lack of unification between the bearings installed in the section housing, head and base, which reduces maintainability and increases the cost of installing a centrifugal submersible pump.

The objective of the invention is to increase the operational reliability and maintainability of the pump, as well as reducing its cost.

The technical result is the elimination of the probability of rotation or loss of carbide bushings from the bearing housing, the unification of the intermediate radial plain bearings installed in the housing and in the end parts.

The specified technical result is achieved in that in a submersible multistage modular centrifugal pump containing a number of similar module sections, the shafts of which are sequentially interconnected by means of splined couplings, each module section has a housing in which steps consisting of an impeller and a guide vane are installed , head and base, in the housing there are installed radial intermediate plain bearings with axial channels for the passage of the pumped liquid, each bearing has a bearing housing nickel and two carbide bushings, one of which is mounted on the shaft, and the second is pressed into the bearing housing, in accordance with the invention, the housing of the radial intermediate plain bearing is pressed into a steel sleeve installed in the housing of the module section, the housings of the radial intermediate plain bearings installed in the head module sections and / or at the base of the module section of the pump, unified with the bearing housing installed in the housing of the module section, the housings of the radial intermediate plain bearings, mounted in the housing, base and head of the module section, with pressed carbide bushings, are unified among themselves.

In order to eliminate the likelihood of a carbide bushing turning or falling out of the bearing housing, the housing of the radial intermediate bearing is pressed into a steel cage. During operation at elevated temperatures, the steel cage, due to the lower coefficient of thermal expansion relative to the coefficient of thermal expansion of the bearing housing made of Niresist cast iron, inhibits the thermal expansion of the bearing housing, thereby reducing the change in interference between the carbide sleeve and the bearing housing and eliminating the possibility of rotation or loss bushings from the bearing housing.

The distance from the shaft end to the nearest radial bearing determines the shaft outreach. The smaller the shaft outreach, the less its radial runout, and therefore, the more reliable the pump unit. The installation of radial bearings both in the base and in the head of the pump section reduces shaft overhang and radial runout. The use of the present invention allows to unify the bearings installed in the housing and end parts of the pump module section.

Submersible multi-stage modular centrifugal pump is shown in the following drawings:

figure 1 shows a General view of a section of a submersible pump;

figure 2 shows a radial intermediate bearing.

Submersible multistage modular centrifugal pump consists of a number of similar module sections 1, the shafts 2 of which are connected in series by means of splined couplings.

Each module section has a housing 3, in which steps consisting of an impeller 4 and a guide apparatus 5, a head 6 and a base 7 are installed. In the housing 3 there are installed radial intermediate bearings 8 with axial channels for the passage of the pumped liquid, each radial intermediate bearing Slide 8 has a housing 9 and two carbide bushings, one of the carbide bushings 10 is mounted on the shaft, and the second of the carbide bushings 11 is pressed into the bearing housing 9.

The housing 9 of the radial intermediate plain bearing 8 is pressed into a steel sleeve 12 installed in the housing 3 of the module section 1.

The radial intermediate plain bearings 8 installed in the head 6 and the base 7 of the module section are unified with the bearing mounted in the housing 3 of the module section.

Submersible multistage modular centrifugal pump operates as follows.

When the shaft 2 rotates, the torque is transmitted to the impellers 4. The formation fluid enters the section through the base 7, sequentially passes through the impellers 4, the guiding devices 5 and the intermediate bearings 8 and exits through the head 6. In this case, the pressure of the reservoir fluid increases.

When the pump is operating, local heating occurs in the intermediate radial bearings 8. In order to eliminate the likelihood of turning or loss of carbide bushing 11 from the bearing housing 9, the radial intermediate bearing housing 9 is pressed into a steel sleeve 12. During operation at elevated temperatures, the steel sleeve 12, due to lower the coefficient of thermal expansion relative to the coefficient of thermal expansion of the bearing housing 9, made of cast iron of niresist type, restrains the temperature extension of the bearing housing 9, thereby reducing the variation of interference between the carbide bushing 11 and the bearing housing 9 and eliminating the possibility of loss or crank hub 11 from the bearing housing 9.

The distance from the end of the shaft to the nearest radial bearing 8 determines the reach of the shaft. The smaller the shaft outreach, the less its radial runout, and therefore, the more reliable the pump unit. The installation of radial bearings 8 both in the base 7 and in the head 6 of the module section 1 of the pump reduces the roll out and radial runout. The radial intermediate bearings 8 installed in the housing 3 and the end parts 6 and 7 of the module section 1 are unified.

Claims (4)

1. Submersible multistage modular centrifugal pump containing a number of similar module sections, the shafts of which are sequentially interconnected by means of splined couplings, each module section has a housing in which steps consisting of an impeller and a guide apparatus, a head and a base are installed, in radial intermediate plain bearings with axial channels for the passage of the pumped fluid are installed in the housing, each bearing has a housing and two carbide bushings, one of which is mounted on lu, and the second pressed into the bearing housing, characterized in that the housing intermediate the radial bearing is press-fitted into a steel holder mounted in the housing module section. 2. The pump according to claim 1, characterized in that the housing of the radial intermediate bearing with a carbide sleeve is installed in the head of the module section and is unified with the bearing housing installed in the housing of the module section. 3. The pump according to claim 1, characterized in that the housing of the radial intermediate bearing with a carbide sleeve is installed in the base of the module section and is unified with the bearing housing installed in the housing of the module section. 4. A pump according to any one of claims 1 to 3, characterized in that the housings of the radial intermediate plain bearings installed in the housing, base and head of the module section, with pressed carbide bushings, are unified among themselves.

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