RU2536731C1 - Rotary multistage pump stage - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to pump engineering, particularly, to downhole multistage pumps used for oil extraction and water feed into a productive oil formation to keep up and to up the formation pressure. A pump stage consists of a closed impeller with a drive disc, blades, driven disc, a distributor including a cylindrical case, top and bottom discs with blades there between to make return channels, and spiral ribs. The spiral inclined ribs are arranged on the cylindrical case inner lateral surface opposite the impeller outlet. He spiral ribs are arranged in a shaped insert made of an elastomer and secured on the distributor cylindrical case surface.

EFFECT: invention is aimed at elongation of the life of stages owing to higher wear resistance of the distributor sidewall opposite the flow exit from the impeller.

3 cl, 3 dwg

Description

The present 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.

A centrifugal submersible multistage pump for pumping formation fluid from oil wells is known, the stages of which contain a closed impeller with specially profiled blades between the drive and driven disks, and a guiding apparatus with vanes that protrude beyond the diametric size of the device’s outer cover (Bogdanov N.A. Submersible centrifugal pumps for oil production. - M .: Nedra, 1968, 38-50 s.). The guide apparatus of such a stage has a cylindrical body, two discs with blades located between them.

The disadvantage of this design is the rather rapid wear of the side wall of the guide apparatus opposite the outlet of the impeller when pumping liquid containing abrasive particles.

Known step of a centrifugal multistage pump, consisting of a closed impeller with a drive disk, blades and a driven disk and a guide apparatus, in which the upper disk has a conical section mated to the inner surface of the housing, and on the outer end surface of the upper disk are made arcuate ribs having a rounding in the direction of movement of the main flow of the pumped formation fluid, with one end of each rib connected to an annular protrusion, and the second end connected to a conical part of the outer surface of the disk (Patent PM PM No. 57395 of the Russian Federation, F04D 13/10, publ. 10.10.2006). The combination of the conical section and the arcuate ribs made on the outer surface of the upper disk of the guide apparatus provides not only the removal of mechanical impurities from the bladeless cavity, but also their directed movement into the flow part of the stage, due to which the degree of destruction of the inner wall of the housing from the side of the bladeless cavity under the influence of mechanical impurities are greatly reduced.

However, this design does not solve the problem of wear of the wall of the housing opposite the outlet of the flow from the impeller.

It is known to use rubber to protect the inner surfaces of pump housings from erosion when pumping suspensions (see, for example, Consideration for proper sizing and material selection to optimize centrifugal slurry pump performance / Gary Davidson // 4 th International Pump User Symposium (1987)).

At the same time, the inner surfaces of the casing are covered with a thick layer of rubber, which is unacceptable for small pumps, which are multi-stage submersible pumps for oil production, since it will be necessary to reduce the diameter of the impeller and the performance will deteriorate.

Closest to the claimed one is a centrifugal multistage pump stage, consisting of a closed impeller with a driving disk, blades and a driven disk, and a guiding apparatus containing a cylindrical body, upper and lower disks with vanes between them, forming return channels, and spiral ribs, with this spiral ribs are placed on the inner side surface of the cylindrical body opposite the impeller exit and are made inclined (Patent No. 2403450 of the Russian Federation, F04D 13/10, publ. 10.11.2010). Spiral ribs are attached directly to the inner lateral surface of the cylindrical body and form channels that increase in width, the front parts of the channels in the region of the impeller exit are open and the rear parts are covered by a screen, which makes them closed on four sides and, as a result, eliminates fluid flow between channels.

A disadvantage of the known step is the high probability of wear of the side wall of the guide apparatus at the attachment point of the spiral ribs under the influence of a fluid stream containing abrasive impurities emerging from the impeller.

The inventive design provides increased service life of the steps by increasing the wear resistance of the side wall of the guide apparatus opposite the flow outlet from the impeller.

The specified technical result is achieved by the fact that in the stage of a centrifugal multistage pump, consisting of a closed impeller with a drive disk, blades and a driven disk and a guiding apparatus containing a cylindrical body, upper and lower disks with vanes between them, forming return channels, and inclined spiral ribs placed on the inner side surface of the cylindrical body opposite the impeller exit, according to the invention, spiral inclined ribs are formed in the volume of the profile vannogo elastomer insert, which is fixed to the surface of the cylindrical body of the guide device.

An elastomer insert may be secured with at least one annular protrusion on its inner surface, interacting with a reciprocal annular groove on the surface of the housing. In addition, it is possible to secure the liner with an annular protrusion on the housing and a reciprocal annular groove made in the liner.

The formation of inclined ribs in the volume of the profiled liner increases the wall thickness of the guide vane at the outlet of the flow from the impeller, which leads to an increase in the service life of the stage.

The use of an elastomer, such as rubber, for the manufacture of a profiled liner, first of all, ensures the simplicity of the formation of spiral inclined ribs in it. In this case, it is possible to use a rubber insert with a thickness sufficient to achieve high resistance of the material to water-abrasion wear while maintaining the performance indicators.

The essence of the invention is illustrated by the following drawings.

In FIG. 1 shows a meridional section of the inventive step with an annular groove on the housing of the guide apparatus for attaching a profiled liner;

in FIG. 2 - meridional section of a profiled insert (shown only three spiral inclined ribs);

in FIG. 3 presents the results of comparative tests of the standard stage 1 VNN5-25 manufactured by Novomet-Perm, and the claimed design, which differs from the standard stage 1 VNN5-25 only by the presence of ribs.

The centrifugal stage of a multistage pump consists of a closed impeller 1 and a guide apparatus 2 (Fig. 1). The impeller 1 has a drive 3 and a driven 4 discs with blades 5 located between them, forming a flow cavity. The guide apparatus 2 comprises a cylindrical body 6, an upper disk 7 and a lower disk 8, between which blades 9 are located, forming return channels.

Opposite the exit from the impeller 1, spiral inclined ribs 10 are formed on the inner side surface of the cylindrical body 6, which are formed in a profiled insert 11 (Fig. 1, 2). The shape, inclination and bending of the spiral inclined ribs 10 provide a minimum of hydraulic losses, which helps to maintain the level of pressure and energy characteristics of the stage.

The profiled insert 11 is made of an elastomer, for example, rubber, the thickness of which at the point of entry of the flow is about 3 mm. The liner is fixed in the guide apparatus 2 by means of an annular protrusion 12 formed on it, which is included in the reciprocal groove of the housing 6. This fastening provides ease of manufacture, ease of assembly and reliable fixation.

The stage works as follows.

The liquid leaves the wheel 1 and enters the surface of the spiral inclined ribs 10, which prevent liquid with abrasive particles from entering the inner surface of the wall of the housing 6 of the guide apparatus and its wear (leaching). Next, the liquid enters the return channels of the guide apparatus 2 and moves to the next stage.

On the example of plastic models of guide vanes and metal impellers, the tests of steps 1 VNN5-25 were performed as standard (curves 1) and with spiral inclined ribs on the guide apparatus according to the claimed design (curves 2).

Tests have shown that in the presence of ribs the pressure curve is slightly shifted up and to the right, while the efficiency of the stage remains at the same level.

Thus, a profiled rubber liner, placed at the place where the flow with the abrasive is in front of the exit from the impeller, does not impair the performance of the step when performing the anti-erosion function.

Claims (3)

1. The stage of a centrifugal multistage pump, consisting of a closed impeller with a drive disk, blades and a driven disk and a guide apparatus containing a cylindrical body, upper and lower disks with vanes between them forming return channels, and inclined spiral ribs located on the inner side the surface of the cylindrical body opposite the exit of the impeller, characterized in that the spiral ribs are formed in the volume of the profiled liner of elastomer, which is fixed to the surface and the cylindrical body of the guide apparatus. 2. The step according to claim 2, characterized in that the liner of the elastomer is fixed with at least one annular protrusion on its surface, interacting with a reciprocal annular groove on the surface of the housing. 3. The step according to claim 2, characterized in that the liner of the elastomer is fixed with at least one annular protrusion on the surface of the housing, interacting with a reciprocal ring groove made in the liner.

Images