RU132506U1 - MULTI-STAGE CENTRIFUGAL PUMP WITH INTERMEDIATE SELECTION OF THE PUMPED-over LIQUID - Google Patents

Abstract

The utility model relates to the field of hydraulic engineering, can be used to supply feed water in technological systems at thermal power plants and can improve the reliability and efficiency of the pump. In a multistage centrifugal pump with an intermediate selection of the pumped liquid, the impellers and guide vanes located after the intermediate sampling section are made with a geometry of the flowing part different from the geometry of the flowing part of the impellers and guide vanes located up to the intermediate sampling section. The selection of the pumped liquid is carried out from the section of one of the intermediate stages by means of two diametrically arranged horizontal holes made in it. 1 cp, 2 ill.

Description

The utility model relates to the field of hydraulic engineering, namely to multistage centrifugal pumps with an intermediate selection of the pumped liquid and can be used to supply feed water in technological systems at thermal power plants (TPPs).

Known multi-stage centrifugal pump with an intermediate selection of the pumped liquid containing sections, including a section with an intermediate selection, with impellers and guide vanes installed in them. Intermediate selection is carried out from the third stage of the inner casing by means of six holes drilled in the body of the section with intermediate selection. The pumped liquid through these holes enters the chamber between the outer casing and the butt cover of the inner casing, and from there through the hole in the outer casing it is directed to the sampling pipeline. All impellers, with the exception of the impeller of the first stage, and guide vanes have the same geometry of the flow part. [Malyushenko V.V., Mikhailov A.K. Energy Pumps: A Reference Guide. - M .: Energoizdat, 1981, p. 80, 81].

This design of the pump with intermediate selection is selected as a prototype for the claimed object.

A disadvantage of the known pump is the following.

The impellers and guide vanes in all its stages, except for the impeller of the first stage, have the same geometry of the flowing part. In this case, not all stages will work in the optimal mode, since the first three stages should provide a full flow rate equal to the sum of the nominal feed and the intermediate selection, that is, operate at a larger feed than the others that provide the nominal feed. This reduces the efficiency of the pump, and the greater the value of the intermediate selection relative to the nominal supply, the greater the decrease in the efficiency of the pump.

In addition, since the optimal operating modes for the first group of stages (before intermediate selection) and for the second group of pump stages (after intermediate selection) are different, in the known pump due to the operation of part of the stages in suboptimal modes, increased vibrations occur that reduce the reliability of the pump .

The task to which the utility model is directed is to increase the efficiency and reliability of a multistage centrifugal pump with an intermediate selection of the pumped liquid by optimizing the operation modes of its stages.

The technical result is achieved in that in a multistage centrifugal pump with an intermediate selection of the pumped liquid, containing sections including a section with an intermediate selection, and installed in them impellers and guide vanes, impellers and guide vanes located after the section with intermediate selection, are made with the geometry of the flowing part, different from the geometry of the flowing part of the impellers and guide vanes located up to the section with intermediate selection, while the section with weft selection made with two diametrically located horizontal holes.

The use of impellers and guide vanes having different geometry of the flow part before and after the intermediate selection, with the exception of the impeller of the first stage, which ensures pump-free operation of the pump, allows each group of stages (before and after the intermediate selection) to work in a mode corresponding to its optimal supply, which improves the efficiency and reliability of the pump.

In addition, the possible use of two diametrically located horizontal holes made in the section with intermediate selection allows intermediate selection of the pumped liquid, while ensuring the discharge of radial force in this stage, and thereby improve the reliability of the pump.

The inventive utility model is illustrated by drawings, which show:

Figure 1 - multistage centrifugal pump with an intermediate selection of the pumped liquid, a longitudinal section;

Figure 2 is a fragment of the execution of the tap from the stage with intermediate selection, a cross section (section aa in figure 1).

A multistage centrifugal pump with an intermediate selection of the pumped liquid contains an inlet cover 1 (Fig. 1), a pressure cover 2, sections 3 and section 4 with an intermediate selection. The connectors between the inlet cover 1, sections 3, 4 and the pressure cover 2 are sealed due to the metal contact of the sealing belts and o-rings. In sections 3 and 4, the impellers 5, 6 and guide vanes 7, 8 are located. Two outlets 9 (Fig. 2), with which an intermediate selection is carried out, contain nozzles welded to two diametrically located horizontal holes drilled in section 4, for example, the fifth stage (made with an extended exhaust chamber) perpendicular to the axis of the pump. The impellers 5, 6 and the guiding devices 7, 8 located before and after the intermediate selection (with the exception of the impeller of the first stage) have different geometry of the flowing part: the geometry of the flowing part of the impellers 5 and the guiding devices 7 to the intermediate selection is selected in such a way in order to obtain the pressure required for intermediate selection at full flow rate and tell the flow the energy necessary to create the pressure at the pump outlet, and the geometry of the flowing part of the impellers 6 and the guiding devices 8 after the intermediate The selection was selected different from the geometry of the flow part of the previous stages and is designed for flow rate less by the amount of selection. Rotor bearings - radial plain bearings 10 with forced lubrication. End seals 11 of the pump rotor are mechanical end-type. The hydraulic heel 12 is used to unload the rotor from axial forces.

The pump operates as follows. When the rotor rotates from the drive, the pumped liquid in full through the inlet pipe enters the impellers 5 and the guiding devices 7, located before the intermediate selection, carried out in section 4 of the fifth stage. As a result of the interaction of the blades of the impellers 5 with the fluid flow, the mechanical energy of the drive is converted into flow energy. After the fifth stage, the pumped liquid in the volume reduced by the amount of withdrawal flows to the subsequent impellers 6 and guide vanes 8, which have a different geometry of the flow part, which provides the specified parameters at the pump outlet.

Using the proposed utility model allows, in comparison with the prototype, to increase the reliability and efficiency of the pump.

Claims (2)

1. A multistage centrifugal pump with an intermediate selection of the pumped liquid, containing sections including a section with an intermediate selection, and impellers and guide vanes installed in them, characterized in that the geometry of the flowing part of the impellers and guide vanes located after the intermediate sampling section, made different from the geometry of the flowing part of the impellers and guide vanes located up to the section with intermediate selection, and is designed for flow rate less by the amount of intermediate weft selection. 2. The pump according to claim 1, characterized in that the section with intermediate selection is made with two diametrically located horizontal holes.

Images