RU2339848C2 - Centrifugal pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to centrifugal pumps designed to pump over fluids with abrasive inclusions, for example, oil, and incorporating hydrostatic bearings lubed by pumped fluid. The centrifugal pump incorporates housing with an inlet branch pipe, a shaft with impellers running in bearing assemblies representing the hydrostatic bearings, their working chambers communicating with the pump inlet branch pipe via the fluid purification device arranged at the inlet branch pipe top and made up of a casing with a cover. The said device communicates with the branch pipe via a number of orifices. The pump inner chamber is separated by a partition into an intake chamber and an accumulating chamber. The aforesaid intake chamber lower section communicates with the pump chamber via the intake branch pipe orifices and with the accumulating chamber via the gap provided between the said partition and the cover. The aforesaid accumulating chamber top part is furnished with orifices to communicate with the hydrostatic bearings and with baffles arranged nearby the aforesaid orifices. The aforesaid baffles are jointed to the enclosure covering the said orifices, at its center and along its edges.

EFFECT: higher reliability and longer life of pump hydrostatic bearings ensured by ruling pout ingress of foreign particles into hydrostatic bearings.

2 cl, 5 dwg

Description

The invention relates to general engineering, and more particularly to centrifugal pumps designed for pumping liquids with abrasive inclusions, such as oil, and having hydrostatic bearings lubricated by the pumped liquid.

A screw centrifugal pump is known, comprising a housing, a shaft with impellers mounted on the shaft, and sliding bearings with hydrostatic cavities installed in the housing at both ends of the shaft, which are hydraulically connected to the pump outlet, specifically to the output spiral manifold (RU 2062360 C1, 06/20/1996) . To ensure the serviceability and resource of bearings in the specified pump, the working surfaces of the bearings are made of wear-resistant material - tungsten carbide or based on tungsten carbide, and the hydraulic connection of the bearings is made to the internal cavity of the pump output spiral collector through its side surface. With this connection, a separating effect is ensured, which limits the number and size of foreign particles in the fluid sampled on the bearings.

The disadvantage of the analogue is that the separating effect due to the movement of the liquid along the spiral manifold of the pump, as the operating experience of such a pump shows, does not exclude the possibility of foreign particles entering the bearing, especially particles that exceed the size of the nozzle openings and can lead to overlap of the nozzles, violation operation of the bearing and, as a result, its failure and the pump. This significantly reduces the reliability of the bearing and pump.

Closest to the invention is the centrifugal pump shown in the same patent, comprising a housing with an outlet nozzle, a shaft with impellers, which is mounted in support assemblies including hydrostatic bearings, the working cavities of which are connected to the outlet nozzle of a centrifugal pump through a fluid purifier (RU 2062360 C1, 06/20/1996). In the known pump, the hydrostatic cavities of the bearings are hydraulically connected to the pump outlet through a centrifugal separator. The separator has an inlet, which is hydraulically connected to the pump outlet, and two outlets, respectively, for purified and contaminated liquid. The output of the separator for pure liquid is hydraulically connected to the inlets to the hydrostatic cavity of the bearings.

The known pump has the following disadvantages:

- to drain contaminated liquid from the separator, an additional flow rate of the liquid pumped by the pump is required, which reduces the pump efficiency;

- installation of additional rotating parts (drum) is required on the pump shaft, as a result of which the rotor is lengthened and the design of the pump is complicated;

- the efficiency of the separator significantly depends on the viscosity of the liquid - with an increase in viscosity, the efficiency of the separator decreases, so when pumping, for example, oil, the viscosity of which can vary by orders of magnitude, the separator will be unstable; at low oil temperature, the degree of its purification in the separator will be insufficient.

The problem to which the invention is directed is to increase the reliability and service life of the pump bearings by preventing foreign particles from entering the bearings capable of blocking the nozzles of the bearings and disrupting their operation, and by reducing the total amount of abrasive particles in the fluid drawn to the bearings.

The technical result obtained is to create a pump in which the most efficient cleaning of foreign particles of the working fluid is taken from the pump outlet to the bearings.

To achieve the technical result in a centrifugal pump containing a housing with an outlet pipe, a shaft with impellers, which is installed in the support nodes, including hydrostatic bearings, the working cavities of which are connected to the outlet pipe of the centrifugal pump through a device for cleaning liquid, according to the invention, a cleaning device liquid is installed in the upper part of the outlet pipe, connected to it through a series of holes and consists of a housing with a cover, the internal volume of which is divided by a hole to the inlet cavity and the accumulation chamber, and the inlet cavity is connected on the lower side to the pump cavity through openings in the outlet pipe, and to the accumulation chamber through the gap between the partition and the lid, the accumulation chamber in the upper part has openings through which it is hydraulically connected with hydrostatic bearings and has deflectors installed at the holes, which are connected to the shell above the holes and on the sides of the holes, and the lower edge of the deflectors is located below the level of the holes and ki.

The storage chamber of the centrifugal pump can be made removable.

Figure 1 presents a diagram of a centrifugal pump with a siphon and a hydrostatic bearing in section perpendicular to the axis of the pump; figure 2 is a view along arrow A of the holes in the upper part of the wall of the outlet pipe; figure 3 is a section bB in figure 1, a structural diagram of a screw centrifugal pump with hydrostatic bearings, to which the working fluid is supplied through a siphon located on the pump outlet; figure 4 - node In figure 3, a hydrostatic bearing with a jet and a hydrostatic chamber; figure 5 is a schematic drawing of a siphon with a removable storage chamber.

The pump contains a housing 1, an outlet pipe 2, a shaft 3, supported by hydrostatic bearings 4 and 5, a siphon formed by the housing of the device 6 for cleaning liquid, a partition 7, a deflector 8 and a cover 9. The inlet cavity 10 of the device 6 for liquid cleaning is connected to the outlet from the pump through openings 11 made in the upper part of the outlet pipe 2. The partition 7 forms, together with the device case 6, a storage chamber 12 and separates the storage chamber from the inlet cavity 10 of the device 6. The shape and location of the partition 7 provides a variable flow area of the input cavity of the device 6, tapering from input to output. Between the partition 7 and the cover 9 there is a gap for the passage of liquid into the accumulation chamber 12 from the inlet cavity 10 of the device 6. The accumulation chamber 12 is connected to the hydrostatic bearings 4 and 5 by a pipe 13 through openings 14 in the housing of the device 6 for cleaning the liquid. The holes 14 are separated from the storage chamber 12 by a deflector 8, which provides a fluid supply to the holes from below. Bearings 4, 5 have hydrostatic cavities 15 and jets 16.

The storage chamber 12 may be removable for ease of cleaning. In this case, as shown in Fig. 5, the storage chamber 12 is made in the form of a truncated thin-walled vessel with an open cylindrical shell 17. A partition 7 is welded from the side open side and from the bottom of the shell 17. Holes 14 are made on the cylindrical shell in the upper part for hydraulic connection with bearings 4, 5. On the inner side of the shell 17 at the holes 14, deflectors 8 are installed, which are connected to the shell 17 above the holes 14 and on the sides of the holes 14, and the lower edge of the deflectors 8 is located below the level of holes TIFA 14 and partitions 7. The storage chamber is secured to the device body 6 for a cleaning fluid via the cover 9.

The pump operates as follows. When the pump delivers liquid, part of the liquid from the pump outlet through the holes 11 in the pipe 2 is taken from the main flow and enters the inlet cavity 10 of the device 6 for cleaning the liquid. Due to the location of the holes 11 in the upper part of the outlet pipe 2, a minimum capture of large foreign particles is ensured, because due to the separation effect in the pump, the main proportion of foreign particles will be at a larger radius of the housing, and at the pump outlet, respectively, in the lower part of the pipe 2. Upward direction of fluid movement with a low speed in the inlet cavity 10 further reduces the possibility of entrainment of foreign particles by the stream. The flow entering the storage chamber 12, flowing through the partition 7, first moves in a downward direction, and then, due to the presence of a deflector 8, it turns and acquires an upward direction along the path to the openings 14 (in Fig. 1, the fluid movement is shown by arrows). The predetermined rotation of the fluid flow and its low speed ensure effective deposition of the remaining particles captured by the flow in the storage chamber 12 and the exclusion of their falling into the nozzles 16 of the bearings 4, 5. This increases the reliability and service life of the bearings 4, 5 and the pump, including the intended one for pumping contaminated liquids, such as oil and water.

Claims (2)

1. A centrifugal pump comprising a housing with an outlet nozzle, a shaft with impellers, which is mounted in support units including hydrostatic bearings, the working cavities of which are connected to the outlet nozzle of a centrifugal pump through a fluid purifier, characterized in that the fluid purifier is installed in the upper part of the outlet pipe, connected to it through a series of holes and consists of a housing with a cover, the internal volume of which is divided by a partition into the inlet cavity and the storage chamber, p Moreover, the inlet cavity is connected on the lower side to the pump cavity through openings in the outlet pipe and to the storage chamber through the gap between the partition and the cover, the storage chamber in the upper part has openings through which it is hydraulically connected with hydrostatic bearings and has deflectors installed at the openings, which connected to the shell above the holes and on the sides of the holes, and the lower edge of the deflectors is located below the level of the holes and the baffle. 2. The centrifugal pump according to claim 1, characterized in that the storage chamber is removable.

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