RU2449176C2 - Stage of submersible multi-stage centrifugal pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: stage of a submersible multi-stage centrifugal pump comprises guide vanes 7 and an impeller 4, which comprises drive and cover discs 5, 6, between which there are blades, and a hub. On the drive disc 5 of the impeller 4 there is a blade rim 10. The impeller 4 is made in the form of a solid-cast structure from cast iron, between side faces of each blade of the blade rim 10 and the drive disc 5 there are fillets. Height of the blade rim 10 does not exceed minimum distance between the drive and cover discs 5, 6, and the radius of fillets makes from 0.1 to 0.8 of this value.

EFFECT: higher corrosion resistance, wear resistance of a submersible centrifugal pump stage, reduced speed of salt deposition and increased process capabilities during manufacturing, and also reduced prime cost and higher power parameters of a submersible centrifugal pump stage.

8 cl, 5 dwg

Description

The invention relates to petroleum engineering, in particular to multistage submersible pumps for pumping formation fluid from wells.

Steps with an additional blade ring compared to centrifugal steps with the same diametrical dimensions have a higher pressure characteristic in the entire range of feeds of the stage, while its uniformly falling shape is ensured.

Performing a blade ring on the driving wheel of the impeller allows increasing the pressure and efficiency of the pump stage, as well as optimizing the axial force acting on the impeller, which increases the reliability of the pump.

Currently, impellers with a blade rim on the drive disk (impellers) are made of powder materials.

Patent RU 2245761 C2 (IPC B22F 7/06, B22F 3/26, publ. 02/10/2005) presents a step containing an impeller made of technical iron powder, and impellers are made on the outer surface of the driving disk of the impeller.

Closest to the invention is a centrifugal-vortex stage of a centrifugal pump containing a guiding apparatus and an impeller made of powder materials [Ageev Sh.R., Grigoryan E.E., Makienko G.P. Russian installations of vane pumps for oil production and their application. Encyclopedic reference book. Perm: LLC “Press-Master”, 2007. - P.75, fig.2.8v].

The disadvantages of these steps are due to the features of the technology of their manufacture and design features.

The powder material is porous, it is usually impregnated with copper, steps from it, compared to solid cast steps from similar materials, have insufficiently high wear resistance and corrosion resistance. The cost of powder steps exceeds the cost of steps made by casting from a similar material. Steps made from powder materials have a higher rate of scaling due to the presence of porosity and foci of corrosion. The lack of technological capabilities is due to the fact that in powder technology it is difficult to manufacture inclined forms and fillets, so it is difficult to manufacture impellers of complex shapes with high energy parameters.

The technical result achieved by the implementation of the invention is to increase the corrosion resistance, wear resistance of a submersible centrifugal pump stage, reduce the scaling rate and increase technological capabilities in manufacturing, as well as reduce the cost and increase the energy parameters of a submersible centrifugal pump stage.

The specified technical result is achieved in that the step of the submersible multistage centrifugal pump contains a guiding apparatus and an impeller, which contains a drive and cover disks between which the blades are located, and a hub, and a blade ring is made on the drive wheel of the impeller, in accordance with the invention, the impeller made in the form of a cast-iron construction made of cast iron, between the side faces of each blade of the scapular blade and the leading disk rounding is made, and the height of the scapular crown and does not exceed the minimum distance between the drive and cover disks of the impeller, and the radius of rounding is from 0.1 to 0.8 of this value.

In addition, in the particular case of the invention, in the impeller, the angle between each blade of the blade rim on its periphery and radius is from minus 45 ° to plus 45 °.

In addition, in the particular case of the invention, the shoulder blade is made in the form of alternating cells open from the outside, or in the form of alternating channels.

In addition, the radius at the entrance to the guiding apparatus is from 0.1 to 3 of the minimum distance between the drive and cover disks of the impeller.

In addition, in the particular case of the invention, cast iron contains, in particular, silicon, manganese, chromium, cerium, phosphorus and sulfur with the following contents of these elements, wt.%:

carbon 3,5-3,9 silicon 2.1-2.7 manganese 0.4-0.6 chromium <0.12 sulfur 0.05-0.07 phosphorus <0.3 cerium <0.03 boron <0.01

In addition, in the particular case of the invention, cast iron contains, in particular, silicon, manganese, chromium, nickel, copper, phosphorus and sulfur in the following contents of these elements, wt.%:

carbon 2.7-3.1 silicon 1.2-1.9 manganese 0.85-1.5 chromium 0.7-1.5 nickel 15-17 copper 6.1-8 sulfur <0.03 phosphorus <0.25 aluminum 0.01-0.3 magnesium 0.01-0.07

In addition, in the particular case of the invention, cast iron contains, in particular, silicon, manganese, chromium, nickel, copper, phosphorus and sulfur in the following contents of these elements, wt.%:

carbon 3.25-3.6 silicon 1.8-2.4 manganese 0.5-0.85 chromium 0.1-0.2 nickel 0.1-0.3 copper 0.2-0.5 sulfur 0.09-0.15 phosphorus <0.1 tin 0.06-0.1

The cast iron impeller makes it possible to get rid of porosity in comparison with powder steps made of similar materials, to obtain higher wear and corrosion resistance, and lower cost.

Steps made by casting have higher corrosion resistance compared to steps made by sintering technologies of powder materials. The porous structure of powder materials as copper is washed out does not impede the penetration of an aggressive environment deep into the material - the contacting surface increases by several times, which leads to the rapid decommissioning of the steps.

The impeller made of Niresist cast iron has a lower scaling rate compared to conventional powder material due to the absence of foci of corrosion, which are salt deposition centers. In addition, in places where corrosion occurs, a potential difference appears, which also contributes to the deposition of salt ions.

The use of casting technology allows to achieve higher technological capabilities, in powder technology it is difficult to manufacture inclined forms and fillets, thus, it is difficult to manufacture impellers of complex shapes with higher energy parameters.

Studies have shown that the height of the blade rim is greater than the distance between the drive and cover disks of the impeller, it is not economically profitable, since it increases the mounting height of the submersible pump stage containing the impeller, and also does not significantly increase the pressure and efficiency.

The manufacture of such fillets between the lateral faces of each blade of the blade ring and the drive disc, such that the fillet radius is from 0.1 to 0.8 of the minimum distance between the drive and cover disks of the impeller, allows to reduce hydrodynamic losses during fluid flow in the gap between the impeller and the guide apparatus and thereby increase the efficiency and pressure of the stage. The hydraulic losses in round pipes are less than in square pipes of the same area. The highest flow rate in the stage between the exit of the impeller and the entrance to the guide apparatus. Hydraulic losses depend on the flow rate squared. The implementation of the radius at the entrance to the guide vane, comprising from 0.1 to 3 of the minimum distance between the leading and cover disks of the impeller, allows you to make the entrance to the channels of the guide vane smoother and therefore reduce hydraulic losses at the entrance to the vane.

From the point of view of technology and hydrodynamics, the angle between each blade of the blade rim of the impeller and a radius from minus 45 ° to plus 45 ° is most optimal. At angles close to zero, the manufacturability of the impeller is higher. At positive angles, the flow rate of the working fluid in the gap between the impeller and the guide apparatus is higher; therefore, the head of the stage is higher; at negative tilt angles, the speed is lower, respectively, the hydrodynamic losses are less and in some cases it can be higher than the stage efficiency.

A brief description of the graphic materials explaining the invention.

Figure 1 shows the stage of a submersible multistage centrifugal pump in the context of the section of the submersible multistage pump.

Figure 2 - the impeller with a blade rim in the form of a combination of alternating cells and channels.

Figure 3 - the impeller with a blade rim in the form of alternating cells.

Figure 4 - the impeller with a blade rim in the form of alternating channels.

Figure 5 - fillet between the shoulder blades of the scapular crown and the leading disk.

Section 1 of a submersible multistage centrifugal pump comprises a shaft 2, a housing 3, in which steps are installed, each of which consists of an impeller 4 containing a hub, a drive 5 and a cover 6 discs between which the blades are located, and a guide apparatus 7, a head 8 and base 9. On the drive disk 5 of the impeller 4, made in the form of a cast-iron construction made of cast iron, a shoulder blade 10 is made. The shoulder blade can be made in the form of alternating cells open from the outside 11 (Fig. 3), channels 12 (Fig. 4) or in e combination of alternating cells and channels (Figure 2).

Between the side faces of each of the blades of the blade rim 10 and the leading disk 5, rounding is made; the height of the blade rim 10 does not exceed the minimum distance between the drive 5 and the cover disk 6 of the impeller 4, and the radius R of the fillets is from 0.1 to 0.8 of this value.

The stage works as follows. When the shaft 2 of the submersible multistage centrifugal pump is rotated, torque is transmitted to the impellers 4. The formation fluid enters the section through the base 9, sequentially passes through the impellers 4, the guiding devices 7, and exits through the head 8. In this case, the pressure of the formation fluid increases.

When the impeller 4 rotates due to the presence of a blade rim 10 on the drive disk 5, the fluid in the sinus between this disk and the guide device 7 rotates at a greater angular speed than in the absence of a blade rim. There is a toroidal vortex, due to which there is a transition of fluid from the impeller 4 to the guide apparatus 7.

The presence of fillets between the side faces of each blade of the blade rim 10 and the driving disk 5 reduces hydraulic losses during the flow of fluid in the blade rim 10, since the flow occurs along rounded rather than rectangular channels. The reduction in hydraulic losses leads to an increase in pressure.

From the point of view of technology and hydrodynamics, the angle between each blade of the blade rim 10 of the impeller 4 and the radius R from minus 45 ° to plus 45 ° is most optimal. At angles close to zero, the manufacturability of the impeller is higher. At positive angles, the speed in the working fluid in the gap between the impeller and the guide apparatus is higher, therefore, the head of the stage is higher, at negative tilt angles, the speed is lower, respectively, the hydrodynamic losses are smaller and in some cases can be higher than the efficiency of the stage. RA is the radius at the entrance to the guiding apparatus.

Claims (8)

1. The step of a submersible multistage centrifugal pump, comprising a guiding apparatus and an impeller, which contains a driving and cover disks between which the blades are located, and a hub, and a blade ring is made on the driving disk of the impeller, characterized in that the impeller is made in the form of a cast cast iron constructions, roundings are made between the lateral faces of each blade of the blade rim and the driving disk; the height of the blade rim does not exceed the minimum distance between the driving and covering disks of the impeller, and the radius of rounding is from 0.1 to 0.8 of this value. 2. The step according to claim 1, characterized in that in the impeller the angle between each blade of the blade of the blade on its periphery and the radius is from minus 45 ° to plus 45 °. 3. The stage according to claim 1 or 2, characterized in that the blade rim of the impeller is made in the form of alternating cells open from the outside. 4. The stage according to claim 1 or 2, characterized in that the blade rim of the impeller is made in the form of alternating channels. 5. The step according to claim 1, characterized in that the value of the radius at the entrance to the guide apparatus is from 0.1 to 3 of the minimum distance between the drive and cover disks of the impeller. 6. The stage according to claim 1, characterized in that the cast iron contains, in particular, silicon, manganese, chromium, cerium, phosphorus and sulfur, with the following content of these elements, wt.%:
carbon 3,5-3,9 silicon 2.1-2.7 manganese 0.4-0.6 chromium <0.12 sulfur 0.05-0.07 phosphorus <0.3 cerium <0.03 boron <0.01 7. The stage according to claim 1, characterized in that the cast iron contains, in particular, silicon, manganese, chromium, nickel, copper, phosphorus and sulfur, with the following content of these elements, wt.%:
carbon 2.7-3.1 silicon 1.2-1.9 manganese 0.85-1.5 chromium 0.7-1.5 nickel 15-17 copper 6.1-8 sulfur <0.03 phosphorus <0.25 aluminum 0.01-0.3 magnesium 0.01-0.07 8. The stage according to claim 1, characterized in that the cast iron contains, in particular, silicon, manganese, chromium, nickel, copper, phosphorus and sulfur, with the following content of these elements, wt.%:
carbon 3.25-3.6 silicon 1.8-2.4 manganese 0.5-0.85 chromium 0.1-0.2 nickel 0.1-0.3 copper 0.2-0.5 sulfur 0.09-0.15 phosphorus <0.1 tin 0.06-0.1

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