RU141221U1 - STEP OF SUBMERSIBLE MULTISTAGE CENTRIFUGAL PUMP - Google Patents

Abstract

1. The step of a submersible multistage centrifugal pump, comprising a closed centrifugal impeller, including a driving and driven disks with blades placed between them, and a guiding apparatus, including a cage, lower and upper disks, between which are placed blades forming flow channels, characterized in that the flow channels have a height in the range of 3.5-6.5 mm, the impeller blades are made with an angle of coverage of the middle line of 120-150 °, and the blades of the guide apparatus are made with an angle of coverage of 180-230 ° .2. The step according to claim 1, characterized in that the constraint coefficient of the blade at the outlet of the guide vane is 0.7.3. The step according to claim 1, characterized in that the number of vanes of the guide apparatus is two. The step according to claim 1, characterized in that it is made in compression or floating versions

Description

The utility model relates to hydraulic engineering and can be used in the oil industry to create submersible centrifugal pumps designed for oil production from wells with low flow rates.

Currently, most of Russia's oil fields are in the late stages of operation. The operating conditions of the wells of such fields are greatly complicated, including the significant content of mechanical impurities and scaling. These deposits significantly reduce the operating time of the ESP, especially of low productivity, comprising at least half of all operating ESP. The heights of the channels of the impellers and guide vanes of the pumps of these plants in order to ensure optimal pump flow at the nominal value are calculated to be minimal. In order to prevent possible clogging of the channels of the impellers and guide vanes of the pump stages of low productivity, the heights of these channels are assigned increased compared with the calculation. For example, for stages of pumps of size 5 with a capacity of 15, 25, 35 m ³ / day, the heights of the channels of the wheels and devices are selected above the calculated ones - at least 3.5 mm. And even at these altitudes of the channels of the wheels and devices, a rather rapid clogging of the channels occurs, which leads to a sharp decrease in the pressure characteristic of the pump and, subsequently, to its failure.

Submersible centrifugal and centrifugal-vortex multistage pumps with axial radial guiding devices are currently widely used for oil production. In such guiding apparatuses, the flow part, as a rule, is formed by means of vanes located between the upper and lower disks (see, for example, Ageev Sh.R., Grigoryan E.E., Makienko G.P. Russian installations of vane pumps for oil production and their application. Encyclopedic reference book. Perm: Press-master LLC, 2007, p. 75).

The disadvantage of these guide vanes is the low pressure of the steps when working on gas-liquid mixtures, due to the presence of an annular bezelless chamber in the stage design.

The prior art stage submersible multistage centrifugal pump, consisting of a collapsible guide vane having a removable upper disk and a lower disk with blades placed between the disks, forming the flowing part of the guide vane from the impeller, made as an open wheel having a hub and vanes (RF patent for utility model No. 599572, IPC F04D 13/10, published on December 27, 2006).

A disadvantage of the known stage is that due to the necessary axial clearances from both ends of the open impeller, the efficiency and pressure parameters of such a stage will always be lower than the parameters of a similar stage with a closed impeller.

Also known is a multistage pump with a radial guide apparatus having a cylindrical body made integrally with the upper disk and the lower disk as a separate part. On the lower, lateral, and upper surfaces of the lower disk, guide vanes are located that form, with the flat surfaces of the upper disks of the given and adjacent steps, as well as with the inner cylindrical surface of the housing, a sequence of guide channels: spiral outlet, diffuser channel, transition channel, and return channel. In this case, recesses are formed on the lateral surface of the lower disk. On the lower disk there is a cavity for placing the impeller (see, for example, A. Bogdanov, Centrifugal submersible electric pumps for oil production. M: Nedra, 1968, Fig. 36, pp. 48-49). In such steps, the bezelless chamber is replaced by a series of channels formed by guide vanes, so they work better on gas-liquid mixtures. Their disadvantage lies in the complexity of manufacturing.

Closest to the technical nature of the invention is the step of a submersible multistage centrifugal pump containing a closed centrifugal impeller, including a driving and driven disks with blades placed between them, and a guiding apparatus, including a cage, lower and upper disks, between which are placed the blades that form the flow channels parts (RF patent No. 2161737, IPC F04D 1/06, F04D 13/10, publ. 10.01.2001).

The known design solves the problem of optimizing the shape of the blades and their inlet and outlet angles to increase the pressure and efficiency, but the task is not to work the pump in wells with a wide range of changes in mechanical impurities in the reservoir fluid, therefore, the number of blades at the impeller is 7, and the angle of coverage of the working wheels lies in the range 98-104 °.

The objective of the proposed utility model is the creation of a submersible multistage centrifugal pump stage, which provides increased reliability, performance, operating hours of pumps in difficult conditions and an increase in their service life.

The technical result achieved by the implementation of the utility model is to increase the efficiency and operating time of low-performance pumps by reducing the likelihood of rapid clogging during production of formation fluid from wells, while ensuring optimal flow at the nominal level.

The task underlying the present utility model, with the achievement of the claimed technical result, is solved by the fact that in the step of a submersible multistage centrifugal pump containing a closed centrifugal impeller, including a driving and driven disks with vanes located between them, and a guiding apparatus, including a cage, the lower and upper disks, between which the blades are located, forming the channels of the flowing part, the heights of the channels of the wheel and the apparatus are in the range of 3.5-6.5 mm, the impeller blades are made with an angle ohm of coverage of the midline 120-150 °, and the vanes of the guide apparatus are made with a coverage angle of 180-230 °.

In addition, the constraint coefficient of the blades at the outlet of the guide vane is 0.7.

In addition, the number of vanes of the guide vane is equal to two.

In addition, the stage can be made in compression or floating versions.

The choice of the height of the impeller blades and the vanes of the guide vane 3.5-6.5 mm allows you to expand the flow channels, which ensures the transfer to a later date of the process of catastrophic clogging of the pump and reduces hydraulic losses. Optimum feed at the nominal level is ensured by choosing the angles of coverage of the midline of the impeller blades lying in the range of 120-150 ° and the vanes of the guide vane 180-230 °.

By reducing the constraint coefficient to 0.7, with an average indicator of this coefficient 0.92-0.95, it becomes possible to delay the moment of occurrence of cavitation. Under these conditions, maintaining the optimal feed rate at the nominal level allows a decrease in the number of vanes of the guide vane to two, in this regard, an increase in the thickness of the outlet edge of the vane and a change in the pitch of the vanes are revealed from the following mathematical expression:

, где

where

ψ is the constraint coefficient of the blades;

t is the pitch of the blades;

σ is the thickness of the output edge (Fig. 3).

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed utility model, made it possible to establish that no analogues were found that are characterized by signs and relationships between them that are identical to all the essential features of the claimed technical solution , a group of utility models is not known and does not explicitly follow for a specialist in the oil and gas industry, but taking into account the possibility of industrial production leniya, we can conclude that the criteria for patentability.

The essence of the utility model is explained further on the basis of the drawings, where:

- in FIG. 1 shows a step of a submersible multistage centrifugal pump, section;

- in FIG. 2 shows the impeller, section;

- in FIG. 3 shows a guide apparatus, section.

In graphic materials, the corresponding structural elements of the stage of a submersible multistage centrifugal pump are indicated by the following positions:

1. - impeller;

2. - a directing apparatus;

3. - drive wheel;

4. - a conducted disk of a wheel;

5. - the upper disk of the guide apparatus;

6. - the lower disk of the guide apparatus;

7. - bezlopatochny cavity;

8. - bezlopatochny cavity;

9. - impeller blades;

10. - hub;

11. - vanes of the guide apparatus;

12. - annular protrusion;

13. - ledge;

14. - clip;

15. - flow channel of the impeller;

16. - bezoplatochny space.

The submersible multistage centrifugal pump stage (Fig. 1) contains a closed centrifugal impeller 1 and a picking apparatus 2. The impeller 1 is made in the form of a single part and consists of a drive 3 and a driven 4 discs, between which the blades are located 9. The guide apparatus 2 is made in in the form of a single part and consists of a holder 14, upper 5 and lower 6 disks, between which are placed the blades 11, which form the channels of the flowing part. Between the upper disk 5 of the guiding apparatus 2 and the driven disk 4 of the impeller 1, as well as between the lower disk 6 of the guiding apparatus 2 and the driving disk 3 of the impeller 1, bezelless cavities are formed, respectively 7 and 8. The height of the flow channels formed between the disks of the impeller and guide vane is selected in the range of 3.5-6.5 mm.

The drive disk 3 has a hub 10 for mounting the impeller on the pump shaft. The angles of the blades 9 of the impeller 1 are selected the smallest - the angle of coverage of each blade along the midline of the blade lies in the range of 120-150 °.

The upper disk 5 of the guide apparatus has an annular protrusion 12 for interacting with the impeller of the stage. The lower disk 6 of the guide apparatus has a protrusion 13 also for interaction with the impeller of the stage. The number of blades 11 of the guide vane is equal to two and they are made with a coverage angle of 180-230 °, and the coefficient of restriction of the vane at the exit of the guide vane is 0.7 by increasing the thickness of the outlet edge of the vane.

The step of a submersible multistage centrifugal pump can be made in compression or floating versions.

The submersible stage with a multistage centrifugal pump works as follows.

During the operation of the stage, the reservoir fluid flows through the flow channels 15 of the impeller 1 (Fig. 2), driven by the pump shaft, and a pressure of the liquid is formed due to centrifugal forces and due to the action of the impeller blades on the fluid flow. Further, the liquid after the wheel enters the bezoplatochny space 16 (Fig. 1) and then into the flow channels of the guide apparatus 2, in which the kinetic energy of the flow is converted into potential energy — the pressure is increased and the flow is rotated to an approximately radial direction to feed the next impeller steps. Together with the reservoir fluid, mechanical impurities, salts, which settle on the walls of the channels, especially in areas with minimal speeds, separation zones, reducing the cross-section of the channels, move along the flow channels of the stage.

Thus, the use of the proposed design of the stage of a submersible multistage centrifugal pump of low productivity, due to the optimally selected parameters and sizes of the blades, blades and their angles, allows to increase the life of the pump by reducing the likelihood of clogging when producing reservoir fluid with a wide range of mechanical impurities, with this ensures optimal feed at the nominal level.

Claims (4)

1. The step of a submersible multistage centrifugal pump, comprising a closed centrifugal impeller, including a driving and driven disks with blades placed between them, and a guiding apparatus, including a cage, lower and upper disks, between which are placed blades forming flow channels, characterized in that the flow channels have a height in the range of 3.5-6.5 mm, the impeller blades are made with an angle of coverage of the middle line of 120-150 °, and the vanes of the guide apparatus are made with an angle of coverage of 180-230 °. 2. The stage according to claim 1, characterized in that the coefficient of constraint of the blade at the outlet of the guide vane is 0.7. 3. The stage according to claim 1, characterized in that the number of vanes of the guide apparatus is two. 4. The step according to p. 1, characterized in that it is made in compression or floating versions

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