RU2402695C1 - Distributor of radial-flow multistage pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: distributor 1 consists of cylindrical case 3, top 4 and bottom 5 plates with vanes 6 arranged there between to make return channels. Inner lateral surface of case 3 accommodate inclined equally space apart vanes 7. Said vanes are formed by two spiral surfaces that make in meridional section a triangle profile 10 elongated at an angle to distributor axis.

EFFECT: minimised hydraulic losses, higher head due to stabilised working fluid flow between stages.

5 cl, 5 dwg

Description

The invention relates to the field of pump engineering and, above all, to multi-stage pumps used for oil production from wells and for supplying water to a productive oil reservoir to maintain and increase reservoir pressure in it.

Currently, centrifugal submersible multistage pumps are widely used for pumping formation fluid from oil wells. The stages of such pumps contain a closed impeller and a guiding apparatus with vanes protruding beyond the diametrical size of the outer cover of the apparatus. The impeller of the stage has specially profiled blades between the driving and driven disks (Bogdanov N.A. Submersible centrifugal pumps for oil production. - M .: Nedra, 1968, p. 38-50).

The guide apparatus of such a stage has a cylindrical body, two discs with blades located between them. The flow path in the stage can be divided into the following sections: the impeller and the blade branch, consisting of a bezelless annular chamber, a vanes guide apparatus and a bezelless annular chamber (Ageev Sh.R., Grigoryan E.E., Makienko G.P. Russian installations of vane pumps and their use: Encyclopedic reference book. Perm: Press-Master LLC, 2007, p.75-76).

The disadvantages of this stage include the low pressure created by the stage at low flow rates, and the instability of the characteristics when working in two- or three-phase oil and gas environments. One of the main reasons for this drawback is the presence of the first of the listed bezlopatochnye annular chambers located at the exit of the wheel.

Known directing apparatus of a multistage centrifugal pump containing a cylindrical body, upper and lower disks, between which are located the blades that form the guide channels for the reservoir fluid. The blades pass into the lateral circumferential ribs, which together with the inner surface of the cylindrical body form lateral guide channels (see, for example, RF patent No. 35392 for utility model, MKI F04D 29/44, publ. 10.01.2004). This design belongs to the class of radial guide vanes (Bogdanov N.A. Submersible centrifugal pumps for oil production. - M .: Nedra, 1968, p. 38-50).

A number of radial guiding devices are known: (author's certificate of the USSR No. 479399, publ. 05.08.76, RF patent No. 2142069, publ. 11.27.99). In the constructions under consideration there are spiral outlets, diffuser channels, transitional side channels and return channels. A similar sequence is typical for large steps. The absence of a bezel-less cylindrical chamber ensures the stable operation of the pump in two- or three-phase oil and gas environments.

The disadvantage of this design is that in the steps of small size and intended for use at low costs, the implementation of these structural elements is complicated by the technological difficulties of manufacturing. In addition, the transition to low costs in this design forces to reduce the cross-section of the channels, which is undesirable, since narrow channels overgrow under conditions leading to scaling.

The inventive design of the guide vane is simpler, provides high pressure characteristics of the stage and reduced energy consumption at maximum costs, as well as efficient operation when pumping gas-liquid mixtures.

The proposed guide apparatus of a centrifugal multistage pump, comprising a cylindrical body, upper and lower disks with vanes between them forming return channels, is characterized in that it is further provided with inclined vanes located on the inner side surface of the cylindrical body between the upper disk of the guide vanes of one stage and the lower the disk of the guiding apparatus of the next stage, and the blades are formed by two spiral surfaces with the formation in the longitudinal (measure iannom) sectional profile in the form of a triangle, elongate angle to the machine axis, and are made with a thickness which decreases in the direction of fluid motion. Depending on the size of the apparatus, inclined blades can be placed on the inner side surface of the cylindrical body or attached to one of the disks. To further increase the pressure in the apparatus, a cylindrical screen can be additionally installed between the upper part of the inclined blades and the lower disk of the next guide apparatus.

To clarify the essence of the invention, drawings of two embodiments are provided.

Figure 1-3 illustrates a first embodiment in which the inclined vanes are located in front of (below) the lower disk (screen not shown).

Figures 4 and 5 show a second construction with inclined vanes located behind the upper disc and a screen.

In figure 1, 4 shows the meridional sections of the steps with the claimed guide apparatus, figure 2, 5 - horizontal sections of the steps, a section along aa, figure 1, 4; figure 3 is a view of the outer edges of the inclined blades along the surface of attachment to the inner wall of the housing (for clarity, the wall of the housing of the guide apparatus is removed).

The pump is recruited from steps consisting of a guide apparatus 1, inside of which an impeller 2 is installed.

The guide apparatus 1 consists (Figs. 1, 4) of a cylindrical body 3, an upper disk 4, a lower disk 5, between which there are blades 6 forming the return channels. Opposite the exit from the impeller 2, between the upper disk 4 of the guide device of one stage and the lower disk 5 of the guide device of the next stage, inclined vanes 7 are placed at an equal distance from each other, which can be attached to the inner side surface of the housing 3 or to the disk 4 or 5 of the guide apparatus 1. In some embodiments, a cylindrical screen 8 can be attached to the upper part of the inclined blades 7.

The thickness of the blade 7 in a horizontal section opposite the exit from the wheel increases from its beginning to the end along the course of the fluid (Fig.2, 5). In addition to the tangential circumferential motion of the fluid, there is also axial motion. In the meridional section, the thickness of the blades 7 along the axis of the liquid decreases (Fig. 1, 4), and the distance between them in the vertical direction increases (Fig. 3). In general, the cross-sectional area of the space between adjacent vanes 7 increases along the course of the fluid. The front parts of the channels between the inclined vanes 7 are open (in the area of exit from the wheel), and the rear ones are closed using the screen 8. Thus, the inclined vanes 7 together with the screen form an annular system of diffusers.

Inclined blades 7 are formed by two spiral surfaces 9, forming in the meridional section a profile in the form of a triangle 10, elongated at an angle to the axis of the apparatus 1 (Fig. 1).

In the second embodiment, the shape of the blades 7 (Figs. 4-5) in the meridional section also has a triangular section, but the long sides of the triangle are somewhat concave, in addition, there is a bend of the blades and a slight torsion, which leads to the closer inclination of the blades at the outlet of the diffuser to the horizontal.

Guide apparatus 1 operates as follows. The flow of pumped liquid, leaving the impeller 2, enters the channels between the inclined vanes 7. Next, the liquid enters the peripheral part of the return channels of the guide apparatus 1 of the same stage (in the first embodiment) or the peripheral part of the return channels of the next (upper) guide apparatus 1 (in the second embodiment), after which it moves radially to the central part and rises through the annular gap to the entrance of the impeller 2 of the next stage.

In the case when it is necessary to ensure the exact relative position of the inclined and back vanes, the first embodiment is preferable. The channels between the inclined blades 7 perform the function of a diffuser, therefore, in the direction of the fluid between the blades, the flow velocity decreases, and the pressure (pressure) increases. The cylindrical screen 8 prevents overflows between adjacent channels (from the end of one channel to the beginning of the next), which are possible due to pressure drops between them.

The proposed design provides a minimum of hydraulic losses and allows to increase the pressure due to the stabilization of the flow of the working fluid between the stages.

Claims (5)

1. The guide apparatus of a centrifugal multistage pump, comprising a cylindrical body, upper and lower disks with vanes between them forming return channels, characterized in that it is further provided with inclined vanes located between the upper disk of the guide device of one stage and the lower disk of the guide device of the next stage moreover, the blades are formed by two spiral surfaces forming a profile in the longitudinal (meridian) section in the form of a triangle elongated at an angle to the axis apparatus. 2. The guide apparatus according to claim 1, characterized in that the inclined blades are placed on the inner side surface of the cylindrical body. 3. The guide apparatus according to claim 1, characterized in that the inclined vanes are attached to the upper or lower disk. 4. The guide apparatus according to claim 1, characterized in that between the upper part of the inclined blades and the lower disk of the next guide apparatus is a cylindrical screen. 5. The guide apparatus according to claim 1, characterized in that the inclined blades are made with a thickness decreasing in the direction of fluid movement.

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