RU2754049C1 - Stage of a multi-stage vane pump - Google Patents

Abstract

FIELD: pumping equipment.

SUBSTANCE: invention relates to the field of pump engineering, mainly to multi-stage electric submersible vane pumps used in the oil industry. The stage of a multi-stage vane pump contains at least an impeller and a guide device. The flow channels on the periphery of the stage elements, at the outlet of the fluid flow from the wheel and at the entrance to the device, are made with an oval shape rounded in the axial projection, the peripheral sections of which provide a flow rotation of at least 180°. The ratio of the radius of the peripheral rounding of the flow channels in the axial projection to their width at the exit of the wheel and the entrance of the device is greater than or equal to 0.65, but less than or equal to 1.95. The internal sections of the inter-blade flow channels of at least one of the stage elements in their axial section are made with an inclination to the axis of rotation of the wheel at an obtuse angle in the direction of fluid movement. The values of these angles (δ_k and /or δ_a) do not exceed 110°. As a result, the axial distance (x₁) between the centers of the flow channels of the wheel and the device in the central region of the stage elements is less than the similar axial distance (x₂) when moving to the peripheral region of the rounding of the channels.

EFFECT: increasing the specific pressure of the stage and reducing its axial size without increasing the hydraulic resistance.

5 cl, 5 dwg

Description

The field of technology.

The claimed technical solution relates to pumping equipment, namely to the stages of vane multistage pumps for pumping various liquid media. It will be most effectively used when applied in multistage electric submersible pumps for oil production.

State of the art.

Multistage vane pumps are widely used in oil production. They are usually subdivided into centrifugal, diagonal (or semi-axial) and axial. The working bodies of centrifugal and diagonal multistage pumps are pump stages, each of which consists of at least an impeller and a guide vane. Additional elements of the stage are support washers made of textolite or silicon carbide (1 or 2 pieces), which separate the impeller rigidly fixed on the rotating shaft from the stationary guide vane. The rotating impeller serves to transfer mechanical energy to the fluid flow. It is a main disk with a hub and a cover disk, between which the blades are located, forming inter-blade channels, through which, under the action of the blades, the pumped liquid moves. This design is called a closed impeller. The guide vane fixed in the pump casing serves to transfer the liquid to the impeller of the next pump stage. In its flow channels, the fluid is inhibited, overcoming external pressure. The guiding device of centrifugal and diagonal pumps generally contains a cylindrical (or combined cylindrical-conical) housing, upper and lower discs with blades (blades) between them, forming return channels converging to the throat, which has a support collar. Through the throat of the guide vane, the pumped liquid enters the channel of the impeller hub of the next pumping stage [see. V.N. Ivanovsky, A.A. Sabirov, A.V. Degovtsev et al. "Design and research of dynamic pump stages." - M: Russian State University of Oil and Gas named after THEM. Gubkin, 124s.].

), в которой протекает перекачиваемый поток. Т.е. энергетическая эффективность ступени обратно пропорциональна ее гидравлическому сопротивлению. Moving in the stage of a vane pump, the pumped liquid is subjected to the action of centrifugal force, which increases the kinetic energy of the flow, and the braking force of hydrodynamic resistance. The magnitude of the hydrodynamic resistance forces is directly proportional to the hydraulic resistance of the stage (

), in which the pumped stream flows. Those. the energy efficiency of a stage is inversely proportional to its hydraulic resistance.

The main design and operation feature of known analogs - stages of multistage centrifugal pumps is that all liquid passes through the stage once, moving, mainly in the inter-blade channels, perpendicular to the axis of rotation of the pump (more precisely, the axis of rotation of the impeller) [see, for example, Patent US 4511307, cl. F04D 29/02, 29/04, publ. 04/16/1985; Patent RU 2403450, cl. F04D 1/06, 13/10, 29/44, publ. June 19, 2009; Patent CA 2803993 cl. F04D 29/22, 29/12, 29/40, publ. 04/26/2016]. In the impeller of such a stage, the movement of the liquid is directed from the center to the periphery, and in the guide vane - from the periphery to the center. Exceptions are sections of annular flow channels in the impeller hub, on the periphery of the guide vane (more precisely, in the annular channel before entering its interscapular channels) and in its throat (at the outlet of the interscapular channels of the guide vane). In these relatively short sections, the fluid moves mainly parallel to the axis of rotation of the impeller. The angle between the directions of the fluid flow in the inter-blade channels of the impeller and the inter-blade channels of the guide vanes in the axial projection is equal to 180 ° or very close to it. The guiding device of the centrifugal stages has a cylindrical body.

The flow of liquid passing through the flow channels of the diagonal pump stage is directed not radially, as in centrifugal pumps, and not parallel to the axis, as in axial pumps, but obliquely, as if diagonally of a rectangle composed of radial and axial directions. The oblique direction of the flow creates the main design feature of diagonal pumps - the arrangement of the impeller blades perpendicular to the meridional flow and inclined to the pump axis. This circumstance makes it possible to use the combined action of lifting and centrifugal forces when creating a pressure [see. Karelin V. Ya., Minaev A. V. “Pumps and pumping stations: Textbook. for universities "2nd ed., rev. and additional - M .: Stroyizdat, 1986. - 320 p.]. In the highly efficient diagonal stages of submersible pumps "REDA, 675 Series" (USA), with which the authors of the proposed technical solution had to work, the angle between the directions of fluid flow in the inter-blade channels of the impeller and the inter-blade channels of the guide vanes in the axial projection is 80 ° ÷ 120 ° , and the angles between the directions of fluid movement in the impeller hub or the throat of the guide vane and the directions of fluid movement in the interscapular (interscapular) channels are 30 ° ÷ 50 °. A classic example of a diagonal-type pumping stage, consisting at least of an impeller and a guide vane in which the inter-blade channels of the impeller and the guide vane are made with an inclination towards the axis of rotation towards each other [see. for example, Patent US 2013 / 0058777A1 cl. F04D 29/54, publ. 03/07/2013, Patent RU 188224U1 class. F04D 10/13, 29/22, 29/041, publ. 27.08.2018].

The closest technical solution to the claimed device is a stage of a multistage vane pump, the authors of which are the applicants of this technical solution [see. Patent RU No. 2735978 cl. F 04D 1/06, 13/10, 29/22, 29/44, publ. 11.11.2020]. We called it the “oval” type step, because it does not fit in its essence any of the above stages of vane pumps. This stage differs in that the inter-blade channels at the outlet of the fluid flow from the impeller and the return flow channels of the guide vane at the flow inlet into the guide vane in their axial section form peripheral rounded oval-shaped sections passing into each other, which smoothly mate with the internal sections of the channels perpendicular the axes of rotation of the impeller located at the inlet of the fluid flow to the inter-blade channels of the impeller and at the outlet from the flow channels of the guide vane, while the ratio of the radius of the peripheral curvature of the channels (r _ka ) to their axial width at the outlet from the impeller and at the inlet of the guide vane ( b _ka ) obey the relation:

Moreover, the radius of this peripheral rounding of the channels (r _ka ) can be either a constant value along the entire length of each rounded section, or a variable, but obeying relation (1).

The disadvantages of the technical solutions chosen as analogs and prototypes are as follows:

), и повышать их удельный напор (H_уд). Последний параметр равен отношение напора ступени (H_cm) к ее осевому размеру или высоте ступени (h_cm). When designing the stages of multistage vane pumps, it is necessary to improve their energy efficiency, and therefore to reduce the hydraulic resistance (

), and increase their specific head (H _beats ). The latter parameter is equal to the ratio of the step head (H _cm ) to its axial dimension or step height (h _cm ).

), т.е. низкая энергетическая эффективность. А для насосов со ступенями диагонального типа наоборот. Сравнительно низкий удельный напор (H_уд) и гидравлическое сопротивление (

), т.е. высокая энергетическая эффективность. То есть диагональные насосы при одинаковом напоре существенно длиннее центробежных. Multistage vane pumps with centrifugal stages are characterized by a high specific head (H _beats ) and hydraulic resistance (

), i.e. low energy efficiency. And vice versa for pumps with diagonal stages. Relatively low specific head (H _beats ) and hydraulic resistance (

), i.e. high energy efficiency. That is, diagonal pumps with the same head are significantly longer than centrifugal ones.

The use of steps of the "oval" type, described in the prototype, allows you to achieve a compromise result: to provide low values of hydraulic resistance of the step with its relatively small axial size. This means that the "oval" stage has increased energy efficiency at a high specific head.

However, the axial dimension of the "oval" stage (prototype) is larger than that of the centrifugal type stage. Therefore, the specific head of the prototype stage is still less than that of the centrifugal stage. Increasing the specific pressure of the "oval" stage without increasing its hydraulic resistance will reduce the length of the pumping unit without losing its pressure. This is especially important for electric submersible pumping systems.

Disclosure of the proposed technical solution.

The aim of the invention is to increase the specific pressure of a stage of a vane multistage pump by reducing its axial size (height), without a significant increase in its hydraulic resistance, and hence a significant decrease in its energy efficiency.

This goal is achieved due to the following:

In the known stage of a vane multistage pump, consisting at least of an impeller (1), a guide vane (2) and supporting elements-washers (3); moreover, the impeller contains a main disk (4) with a hub (5) and a cover disk (6), between which curvilinear blades (7) are located, forming inter-blade channels of the impeller (8), along which, under the action of the blades, the pumped liquid; and the guide vane contains both the lower (9) and the upper (10) disks with blades (11) placed between them, forming return channels (12) converging to a neck (13) with a support collar, along which the fluid moves to the entrance to next stage impeller; in which the main feature of the "oval" type stage is implemented, namely, the inter-blade channels (8) at the outlet of the liquid flow from the impeller and the return flow channels (12) of the guide vane at the flow inlet into the guide vanes in their axial section form peripheral rounded passages passing into each other other areas are oval in shape, there are the following distinctive features:

1. The inner sections of the inter-blade channels (8, 12) of at least one of the stage elements (impeller and / or guide vane) are made in axial projection meridian section with an inclination to the axis of rotation of the impeller at obtuse angles (δ _to and / or δ _a ) no more than 110 ° in the direction of fluid movement in the stage (see Fig. 1 and Fig. 2)

2. In contrast to the prototype, the rotation of the fluid flow by at least 180 ° in the axial projection of the meridional section is described by the following ratio of the radius of the peripheral curvature of the flow channels (r _ka ) to their width at the outlet of the impeller and the inlet of the guide vane (b _ka ) (cm . Fig. 1 and Fig. 2):

Note that the most optimal from the point of view of achieving the highest specific pressure H _beats , calculated by the formula (2), is achieved under the condition r _ka = CONST. That is, when the shape of the trajectory of the fluid flow is close to a circle.

3. The angles δ _to and / or δ _a between the directions of the fluid flow in the channels in the internal sections can be both constant in magnitude - then in the axial projection the internal sections of the channels will look rectilinear (see Fig. 3 b), and with variable growth the values of the angles δ _to and / or δ a _as they move away from the center of the stage (pump axis) - then in the axial projection these sections of the channels will look curvilinear (see Fig. 3 c). The latter is more optimal when designing multistage pumps with "floating" type stages (not rigidly fixed on the shaft in the axial direction) with support washers. For pumps with "compression" (rigid) fastening of steps on the shaft, the options for steps with variable values of the angles δ _to and δ _a or their constant values are practically equivalent.

4. The following particular cases of the proposed technical solution in the form of the internal sections of the flow channels are possible:

4.1. The inner sections of both the inter-blade channels of the impeller (8) and the reverse inter-blade channels of the guide vane (12) are made with an inclination to the axis of rotation of the impeller at obtuse angles in the direction of fluid movement, the value of which is not more than 110 ° (see Fig. 3, pos. b and pos. c, and Fig. 1).

4.2. The inner sections of the interscapular channels of the impeller (8) are made perpendicular to the axis of rotation of the pump, and with an inclination to the axis of rotation of the impeller at an obtuse angle of not more than 110 ° in the direction of fluid movement, only the inner sections of the interscapular channels of the guide vane (12) are made (see Fig. . 3 item d).

4.3. The inner sections of the inter-blade channels of the guide vane (12) are made perpendicular to the axis of rotation of the pump, and with an inclination to the axis of rotation of the impeller at an obtuse angle of no more than 110 ° in the direction of fluid movement, only the inner sections of the inter-blade channels of the impeller (8) are made (see Fig. . 3 pos. E, and Fig. 2).

Description of drawings.

The essence of the invention is illustrated by graphic materials (Figures).

FIG. 1 shows a drawing of the Stages of a vane multistage pump with a section in the axial projection of the meridian section. In this stage, the inner sections of the inter-blade channels of the impeller and the guide vane are made in axial projection with an obtuse angle to the axis of rotation of the impeller (δ _to > 90 °, δ _a .> 90 °);

FIG. 2 shows a drawing of the Stages of a vane multistage pump with a section in the axial projection of the meridian section. In this stage, the inner sections of the inter-blade channels of the impeller in the axial projection with an obtuse angle to the axis of rotation of the impeller, and in the guide vanes at a right angle (δ _to = 90 °, δ _a .> 90 °); ...

The following designations are adopted in the drawings:

1 - impeller;

2 - guiding device;

3 - supporting elements (washers);

4 - the main disk of the impeller;

5 - impeller hub;

6 - cover disk of the impeller;

7 - curved impeller blades;

8 - inter-blade channel of the impeller formed by blades, main and cover disks;

9 - the lower disc of the guide vane;

10 - top disc of the guide vane;

11 - blades (blades) of the guide vanes;

12 - reverse interscapular channel formed by blades, upper lower discs of the guide vanes;

13 - the throat of the guide vane;

_bк-а - axial width of the flow channels at the outlet of the impeller and at the inlet of the guide vane;

r _to-a - peripheral radius of curvature of the flow channels at the exit from the impeller and at the entrance of the guide vane;

δ _to - the angle of change in the direction of the fluid flow in its axial projection for the inner area of the channels of the impeller;

δ _a - the angle of change in the direction of the fluid flow in its axial projection for the inner region of the channels of the guide vanes;

x ₁ is the distance in axial projection between the centers of the flow channels of the impeller and the guide vane in the inner region of the step (transitions: impeller hub - intershape channel of the impeller, interscapular channel of the guide vane - throat of the guide vane);

x ₂ - distance in axial projection between the centers of the flow channels of the impeller and the guide vane in the peripheral region of the stage of the beginning of rounding of the channels;

h _cm - axial dimension (height) of the step;

D _ct - the outer diameter of the step;

The arrows show the direction of movement of the pumped liquid in the pump stage.

FIG. 3 shows a diagram of the movement of the pumped liquid in the axial projection for different designs of the stage. Continuous arrows show the direction of movement of the pumped liquid in the impeller, intermittent arrows - in the guide vane.

a. Scheme of fluid movement in a vane multistage pump with “oval” -type stages at δ _k = 90 ° and δ _a = 90 ° (Prototype);

b. Scheme of fluid flow in a multistage pump with “oval” -type stages at δ _to > 90 ° and δ _a > 90 °, δ _to = Const and δ _a = Const (Declared technical solution);

v. Scheme of fluid flow in a multistage pump with “oval” -type stages at δ _to > 90 ° and δ _a > 90 °, δ _to ≠ Const and δ _a ≠ Const (Declared technical solution);

d. Scheme of fluid flow in a multistage pump with “oval” -type stages at δ _k = 90 ° and δ _a > 90 °, δ _k = Const and δ _a ≠ Const (Declared technical solution);

e. Scheme of fluid flow in a multistage pump with “oval” -type stages at δ _to > 90 ° and δ _a = 90 °, δ _to ≠ Const CONST and δ _a = Const (Declared technical solution).

where r _ka is the radius of curvature of the fluid flow at the periphery of the impeller and the guide vane;

δ _k is the angle of change in the direction of the fluid flow in its axial projection for the inner area of the impeller channels (exit from the hub channel - entrance to the inter-blade vane channel of the impeller);

δ _a - the angle of change in the direction of the fluid flow in its axial projection for the inner region of the channels of the guide vane (exit from the reverse inter-blade channel of the guide vane - entrance into the throat channel of the device);

8 - inter-blade channels of the impeller;

12 - reverse inter-blade channels of the guide vane;

) лопастного многоступенчатого насоса в зависимости от величины ее осевого размера (h_cm) , при 0 ≤ r_k-a /b_k-a ≤ 2,5) и малом (не более 5°) отклонении потока жидкости в межлопастных каналах от перпендикулярного оси вращения насоса. Значения (

) получены расчетным путем на основе математической модели, разработанной авторами настоящего предполагаемого изобретения на базе формул и диаграмм, представленных в литературном источнике [см. Идельчик И.Е. «Справочник по гидравлическим сопротивлениям /под ред. М.О. Штейнберга.» -3-е издание перераб. и доп. - М.: Машиностроение, 1992- 672с]. В качестве базовой модели, для проектирования и расчетов была использована ступень центробежного насоса ЭЦНА5-80 (АО «АЛНАС»). FIG. 4 shows the graph of the dependence of the hydraulic resistance of the inventive stage (

) a vane multistage pump, depending on the value of its axial size (h _cm ), at 0 ≤ r _ka / b _ka ≤ 2.5) and small (no more than 5 °) deviation of the fluid flow in the inter-blade channels from the perpendicular to the axis of rotation of the pump. The values (

) obtained by calculation on the basis of a mathematical model developed by the authors of the present alleged invention based on the formulas and diagrams presented in the literature [see. Idelchik I.E. "Handbook on hydraulic resistance / ed. M.O. Steinberg. " -3rd edition revised. and add. - M .: Mechanical Engineering, 1992- 672s]. A centrifugal pump stage ETsNA5-80 (JSC "ALNAS") was used as a basic model for design and calculations.

от h_cm для ступени с δ_к = 90° и δ_а= 90°, т.е. спроектированной согласно Прототипу; Dot Curve 14 - Shows dependency

from h _cm for a step with δ _к = 90 ° and δ _а = 90 °, i.e. designed according to the Prototype;

от h_cm для ступени с δ_к = 95° и δ_а= 90°, т.е. спроектированной согласно Заявляемому техническому решению, по варианту когда один и углов (δ_к или δ_а) тупой, а второй прямой. Dotted line 15 - Shows dependence

from h _cm for a step with δ _к = 95 ° and δ _а = 90 °, i.e. designed according to the claimed technical solution, according to the option when one of the angles (δ _to or δ _a ) is obtuse, and the second is straight.

от h_cm для ступени с δ_к = 95° и δ_а= 95°, т.е. спроектированной согласно Заявляемому техническому решению, по варианту когда оба угла (δ_к и δ_а) тупые.Curve 16 - Shows dependence

from h _cm for a step with δ _к = 95 ° and δ _а = 95 °, i.e. designed according to the declared technical solution, according to the option when both angles (δ _to and δ _a ) are obtuse.

) лопастного многоступенчатого насоса в зависимости от величины ее осевого размера (h_cm), при 0,65 ≤ r_k-a /b_k-a ≤ 2,5 и повышенном (до 20°) отклонении потока жидкости в межлопастных каналах от направления перпендикулярного оси вращения насоса. Значения (

) получены расчетным путем на основе математической модели, разработанной авторами настоящего предполагаемого изобретения на базе формул и диаграмм, представленных в литературном источнике [см. Идельчик И.Е. «Справочник по гидравлическим сопротивлениям /под ред. М.О. Штейнберга.» -3-е издание перераб. и доп. - М.: Машиностроение, 1992- 672с]. В качестве базовой модели, для проектирования и расчетов была использована ступень центробежного насоса ЭЦНА5-80 (АО «АЛНАС»). FIG. 5 shows the graph of the dependence of the hydraulic resistance of the inventive stage (

) a vane multistage pump depending on the value of its axial size (h _cm ), at 0.65 ≤ r _ka / b _ka ≤ 2.5 and increased (up to 20 °) deviation of the fluid flow in the inter-blade channels from the direction perpendicular to the axis of rotation of the pump. The values (

) obtained by calculation on the basis of a mathematical model developed by the authors of the present alleged invention based on the formulas and diagrams presented in the literature [see. Idelchik I.E. "Handbook on hydraulic resistance / ed. M.O. Steinberg. " -3rd edition revised. and add. - M .: Mechanical Engineering, 1992- 672s]. A centrifugal pump stage ETsNA5-80 (JSC "ALNAS") was used as a basic model for design and calculations.

от h_cm для ступени с δ_к = 90° и δ_а= 90°, т.е. спроектированной согласно Прототипу; Dot Curve 14 - Shows dependency

from h _cm for a step with δ _к = 90 ° and δ _а = 90 °, i.e. designed according to the Prototype;

от h_cm для ступени с δ_к = 110° и δ_а=90°, т.е. спроектированной согласно Заявляемому техническому решению, по варианту когда один и углов (δ_к или δ_а) тупой, а второй прямой. Dotted Curve 17 - Shows Dependency

from h _cm for a step with δ _к = 110 ° and δ _а = 90 °, i.e. designed according to the claimed technical solution, according to the option when one of the angles (δ _to or δ _a ) is obtuse, and the second is straight.

от h_cm для ступени с δ_к = 110° и δ_а= 110°, т.е. спроектированной согласно Заявляемому техническому решению, по варианту когда оба угла (δ_к и δ_а) тупые. Curve 18 - Shows dependence

from h _cm for a step with δ _к = 110 ° and δ _а = 110 °, i.e. designed according to the declared technical solution, according to the option when both angles (δ _to and δ _a ) are obtuse.

The fundamental difference between the new stage and the Prototype is clearly demonstrated by the flow diagram of the pumped liquid in the axial projection with different designs of these stages (see Fig. 3). In the Prototype stage, the fluid movement occurs radially in the inner regions of the flow channels (located closer to the center of the stage), and along an oval trajectory (a circle is a special case of an oval) at the periphery of both the impeller and the guide vane (see Fig. 3.a ). The total turn of the flow in the oval region of the channels occurs by 180 °, and two turns in the inner regions of the step, each by 90 ° (that is, δ _k = 90 °, δ _a . = 90 °). In a stage having a design, according to the claimed technical solution, the peripheral rotation of the direction of the liquid flow is the same as in the prototype stage, but the movement of the liquid in the inter-blade channels of at least one of the elements of the stage (impeller and / or guide) of the apparatus occurs in the axial projection obliquely, at an obtuse angle, to the axis of rotation of the pump (see Fig. 3 b-e). The specified angles of turns of the direction of flow can be up to 110 °. As a result, the axial distance between the centers of the flow channels of the impeller and the guide vane in the central region of the stage elements (x1) is less than the axial distance between the centers of these channels at the transition to the peripheral region of the curvature of the channels of the impeller and the guide vane (x2) (see Fig. 1). A decrease in the size x1 also ensures a decrease in the axial size of the step (h _cm ), and hence an increase in its specific head (H _beats ).

For reference: An obtuse angle is an angle greater than 90 ° but less than 180 °.

In the inner regions of the flow channels, the direction of fluid movement in the axial projection is opposite to the main direction of fluid flow inside the stage as a whole. Neither the steps of analogs (centrifugal or diagonal), nor the prototype - our patented "oval" step, have such a feature. The presence of this new feature turned out to be fundamentally possible only in conjunction with the main feature of the "oval" type stage - roundness in the axial projection of the flow channels of the impeller and the guide vane on the peripheral areas of the pump stage elements.

If the value of the ratio (r _ka / b _ka ) is less than 0.65, then there is no practical sense in using a new technical solution, since the decrease in the axial size of the oval step is practically not noticeable. If the value of the ratio (r _ka / b _ka ) is greater than 1.95, then with the same axial dimensions, the steps made according to the design of the Prototype have less hydraulic resistance than the steps made according to the claimed technical solution. In the range satisfying the condition of inequality (3), the hydraulic resistance of the steps having a design according to the claimed technical solution is lower than that of the Prototype steps (see Fig. 4 and Fig. 5).

The small (no more than 20 °) deviation of obtuse angles δ _to and δ _a from the right angle (90 °), inherent in the claimed technical solution, does not significantly increase the local hydraulic resistance of the fluid flow turns in the inner regions of the step elements, but at the same time significantly reduces axial step size.

With a small peripheral axial curvature of the channels, when condition (4) is satisfied:

It is preferable to increase the specific pressure used design stage with two obtuse angles δ _{and k} and δ (90 ° <δ _to <110 °, 90 ° <δ _a ≤ 110 °);

at large curvatures, when condition (5) is satisfied:

a design with one right and one obtuse angle is preferable (90 ° <δ _k <110 °, δ _a = 90 ° or δ _k = 90 °, 90 ° <δ _a ≤ 110 °, from the point of view of hydrodynamics this is equivalent).

With medium rounding, when condition (6) is satisfied:

the use of any of the claimed designs gives an almost equivalent result.

In all the variants of the claimed technical solution described above, the same design technique is used to reduce the axial dimension of the step. Namely, the design of the inner part of the inter-blade channels of the stage with a reverse inclination at an obtuse angle to the axis of rotation of the pump. From a hydrodynamic point of view, the three design options for an oval stage with inversely inclined inter-blade channels provide the same result. Therefore, these three stage options can be considered a single technical solution.

The stages of vane pumps are of a single-support structure (with one support washer in the stage), two support structures (with two support washers in the stage) and an unsupported structure (there are no support washers in the stage). To achieve this goal, this does not matter, therefore, they do not have to be mentioned in the limiting part of the claims.

The device works as follows.

During operation of the vane multistage pump, the pumped liquid enters the impeller (1) of the stage, which rotates on the shaft of the vane pump. This takes place through the annular channel of the impeller hub (5). Further, after passing through the annular channel, the liquid makes a turn (usually smooth) and enters the inter-blade channels (8), which are formed by curved blades (7) by the main disk (4) and the cover disk (6). In the inter-blade channels, under the influence of the centrifugal force transmitted by the blades, the fluid flow rate increases. The flow moves in the inter-blade channel, first along the inner section at an obtuse angle of 90 ° ÷ 110 ° with respect to the pump rotation axis, and then along the peripheral sections of the channels along an oval trajectory (a circle is also a special case of an oval). Further, the liquid flow, leaving the flow channels of the impeller, enters the stationary guide vane (2) of the vane pump stage. On the peripheral sections of the return flow channels of the guide vane (12), formed by the upper and lower discs (9, 10) and blades (11), the flow path has an oval shape. Those. it continues the rounded fluid path at the periphery of the impeller. As a result, smoothly rounding off in axial projection on the periphery of the impeller and the guide vane, the fluid flow rotates through a total angle of at least 180 °. Then this flow flows at an obtuse angle of 90 ° ÷ 110 ° with respect to the axis of rotation of the pump along the inner sections of the reverse inter-blade channels of the guide vanes. Coming out of the interscapular channels, the fluid flow makes a turn (usually smooth) and enters the annular channel of the throat (13) of the guide vanes. Then, through the throat of the guide vane, the pumped liquid enters the channel of the impeller hub of the next stage of the multistage vane pump.

Examples of implementation of a technical solution.

A possible embodiment of the “oval” design step with inversely inclined inter-blade channels is shown in Fig. 1. and Fig. 2.

Theoretical calculations based on the mathematical model created by us, carried out for the ETSNA5-80 pump, showed that the stage designs of serial multistage electric submersible pumps can be adapted to the "oval" design with inversely inclined inter-blade channels. Calculations have shown that using such stages it will be possible to reduce the length of the pump by 4 ÷ 18% in comparison with the prototype oval pump with practically the same hydraulic resistance, which means unchanged energy efficiency.

The most optimal technology for manufacturing oval steps with inversely inclined inter-blade channels is investment casting, followed by machining (grinding) on high-performance automatic machines. The materials of the impellers and guide vanes of such stages, manufactured by casting, are modified gray cast iron or corrosion-resistant cast iron of the Nirezist grade. Oval steps with inversely inclined inter-blade channels can also be made of polymer or composite materials.

Claims (7)

1. A stage of a vane multistage pump, consisting at least of an impeller containing a main disk with a hub and a cover disk, between which curved blades are located, forming inter-blade channels of the impeller, along which the pumped liquid moves under the action of the blades, and a guide vane containing an upper and the lower discs with blades placed between them, forming reverse inter-blade channels converging to the throat, along which the fluid moves to the inlet of the next stage impeller, while the inter-blade channels at the outlet of the liquid flow from the impeller and reverse flow channels of the guide vane at the inlet flow into the guide vanes in their axial section form peripheral rounded oval-shaped sections passing into each other, characterized in that the peripheral sections of the flow channels, ensuring the rotation of the fluid flow by at least 180 °, are made obeying the following relation for the sake of mustache of peripheral rounding of channels ( rk-a ) to their axial width at the outlet of the impeller and at the inlet of the guide vane ( bk-a ): 0.65≤ (rk-a / bk-a) ≤1.95, and the inner sections of the inter-blade channels of at least one of the stage elements in their axial section are made with an inclination to the axis of rotation of the impeller at an obtuse angle, but not more than 110 °, in the direction of fluid movement so that the axial distance between the centers of the flow channels of the impeller and the guide vane in the central region of the step elements is less than the axial distance between the centers of these channels in the transition to the peripheral region of the curvature of the channels of the impeller and the guide vane. 2. The stage of a vane multistage pump according to claim 1, characterized in that the obtuse angle of inclination of the inner sections of the flow channels smoothly increases with distance from the center of the stage in its axial section. 3. The stage of a vane multistage pump according to claim 1, characterized in that the inner sections of both the inter-blade channels of the impeller and the return channels of the guide vane are tilted to the axis of rotation of the impeller at an obtuse angle, but not more than 110 °, in the direction of motion liquids. 4. The stage of a vane multistage pump according to claim 1, characterized in that the inner sections of the inter-blade channels of the impeller are made perpendicular to the axis of rotation of the pump, and with an inclination to the axis of rotation of the impeller at an obtuse angle, but not more than 110 °, only the inner sections are made return channels of the guide vane. 5. The stage of a vane multistage pump according to claim 1, characterized in that the inner sections of the return channels of the guide vane are made perpendicular to the axis of rotation of the pump, and with an inclination to the axis of rotation of the impeller at an obtuse angle, but not more than 110 °, in the direction of fluid movement only the inner sections of the inter-blade channels of the impeller are made.

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