RU2485352C1 - Oil delivery rotary pump with rotor running in antifriction bearings and method of improving pump performances - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed delivery oil rotary pump comprises casing and casing cover. Rotor composed of shaft and impeller is arranged between casing and cover. Pump rotor runs in console bearing supports located outside pump casing. Said bearings represent two types of antifriction bearings: spherical two-row roller bearing to take up pump shaft axial load and floating toroidal roller bearing. Both bearings are fitted on the shaft by means of tapered coupling bushes with axial split Impeller is fitted on the shaft with the help of two-sided collet jig with conical sleeves and screws while rotor end seals are fitted on the shaft with the help one-side collet jigs with conical bushes and screws.

EFFECT: reduced noise and vibration, higher reliability and efficiency, longer life

5 cl, 3 dwg

Description

Technical field

A centrifugal main oil pump belongs to the field of radial flow pumps and can be used for pumping crude oil in main oil pipelines.

State of the art

Centrifugal main oil pumps are known, for example, OJSC Sumy Plant Nasosenergomash or the company Sulzer (Switzerland), in which the bearings of the rotor shaft are traditionally sliding bearings. In addition to the fact that the use of these bearings increases the vibrational activity of the pump due to the large radial clearances between the shaft journal and the liner, it is necessary to complicate the design of the bearings due to the need for additional installation of radial-unary bearings to keep the rotor shaft from axial movements caused by accidental loads. Sliding bearings reduce the efficiency (efficiency) of the pump due to the impossibility of creating stationary fluid friction during oscillations of the shaft neck relative to the liner. These bearings heat up significantly and require the use of special devices in the cooling and lubrication system of sliding bearings.

Closest to the invention in terms of the device is a centrifugal pump consisting of a housing and a housing cover, a rotor consisting of a shaft and a blade impeller is installed between the housing and the cover, while the pump rotor is mounted in the cantilever bearing supports external to the pump housing, OJSC Sumy plant Nasosenergomash (Ukraine) and OJSC VNIIAEN (Ukraine) (RF patent No. 106680, IPC F04D 1/00, F04D 29/00, published on July 20, 2011).

The disadvantage of this pump is the presence of gaps in the bearing bearings, which causes dynamic beats in the gaps, contributing to increased noise and vibration (vibration) of the pump.

As for the method of improving the characteristics of the pump through its assembly, the published PCT application WO 2010030802 (IPC F04D 17/02, published March 18, 2010) on a method for assembling a high-performance multistage centrifugal pump in an electric pump assembly is known. However, this method is not intended for assembly of a main oil centrifugal pump and therefore does not take into account many design features of such a pump.

Closest to the invention in terms of the method is a method of improving the characteristics of a pump by assembling its rotor (shaft with an impeller) with bearings, as part of a pump assembly, described in UK patent No. 1255169 (IPC F04C 19/00, published 01.12.1971).

The known method is also not intended for the assembly of a main oil centrifugal pump and therefore does not take into account many design features of such a pump.

Disclosure of invention

The main general objective of the proposed group of inventions is the creation of a centrifugal pump with improved technical and economic characteristics, specifically, with reduced noise and vibration, increased reliability, resource and efficiency through a number of design and technological improvements combined in a single inventive concept in individual basic components of the pump.

The technical result in terms of the device is achieved by the fact that in the main oil centrifugal pump, consisting of a housing and a housing cover, a rotor is installed between the housing and the cover, consisting of a shaft and a blade impeller, while the pump rotor is installed in cantilevers external to the pump housing bearings, the latter according to the invention are made in the form of rolling bearings of two types: a spherical double-row roller bearing, absorbing the axial load of the pump shaft, and a "floating" toroid nogo roller, both mounted on a bearing shaft on the conical clamping sleeves in axial section.

The impeller can be seated on the shaft by means of a double-sided collet clamping device with tapered bushings and screws, and the mechanical seals of the rotor are seated on the shaft by means of one-sided collet clamping devices with tapered bushings and screws, these clamping devices are a combination of two coaxial rings with conical working surfaces with the possibility of displacement of the rings using clamping screws along the axis of the shaft relative to each other with a shaft clamp.

All housing connections can be fastened, including pairs of removable conical pins with threaded ends.

By replacing traditional plain bearings with rolling bearings of the following types: double-row spherical roller bearings and a “floating” toroidal roller bearings, the pump is able to operate under radial and axial loads. In this case, the pump rotor is installed in the cantilever bearings of the rolling bearings external to the pump casing, both bearings are mounted on the shaft on conical coupling sleeves with an axial section.

Also, the keyed connections of the impeller with the rotor shaft of the installation, as well as in the areas of mechanical seals (isolating the pump internal cavity from the surrounding space) have been replaced with new modified collet clearance-free clamping devices, which are a combination of two coaxial elbows with conical working surfaces. The rings are displaced along the axis of the shaft relative to each other. The impeller is seated on the shaft by means of a double-sided collet chuck with conical bushings and screws, and the mechanical seals of the rotor are seated on the shaft by means of one-side collet chucks with conical bushes and screws.

Also, all connections of the housings are fastened, including pairs of removable conical pins with threaded ends.

The technical result in terms of the method is achieved due to the fact that the method of improving the characteristics of the pump by means of its high-precision and practically clearance-free assembly includes the following operations: before assembling the pump in the molded pump housing and in the molded cover of the pump housing, baseline grinding of the seating surfaces of the “paws” of the pump housing and the planes of the connectors - the general horizontal plane of the housing and the cover and vertical mating planes around the holes for the rotor shaft for mounting the bearing housing; for boring from one installation on the boring machine, holes for rings for adjusting the axial clearance of the rotor in the housing, holes for slotted seals of the impeller and holes for bearings in the housing of the bearing assemblies, between the pump housing and the cover of the pump housing and through empty housing of the bearing assemblies, pre-installation of boring bars with boring cutters adjustable flights and then make the connection of the pump housing and cover with studs and two removable conical pins with threaded ends horizontally Flax plane of the connector and its connection empty shells bearing assemblies of screws and removable pairs of conical pins with threaded ends along vertical planes connectors with the housing and the cover of the pump housing; after boring the holes from one installation, disconnect all cases and covers with the removal of all removable conical pins; regardless of the boring operation, from one installation, the pump rotor is assembled from the shaft, the impeller and two shaped sleeves on the shaft participating in the formation of the pump flow path, using a double-sided collet clamping connection with conical bushings and screws and using a precision measuring device in the form of a pipe lengths for pinpointing the location of the impeller on the shaft, then install and mount the shaped bushings on both sides of the collet chuck; then the rotor is installed with the axial clearance adjustment rings previously mounted on its shaft in the pump housing without a cover and the clearances are aligned between the impeller and the rings with axial shaft fixing relative to the pump housing, for example, using technological gaskets; regardless of the installation of the rotor in the pump housing, two bearing assemblies with a spherical double-row roller bearing and a "floating" toroidal roller bearing are separately assembled; followed by adjusting the installation and then dismantling the bearing assembly with a spherical double-row roller bearing on the rotor shaft and on the pump housing to ensure that the clearance between the mating planes of the bearing housing and the pump housing is practically zero due to a corresponding reduction in the thickness of the expansion ring; before final fastening of the pump cover to the pump casing, using studs and conical pins, fixing technological pads are removed from the axial clearances of the shaft relative to the casing; after attaching the pump cover to the pump casing, the mechanical seals are installed between the rotor shaft and the assembled pump casing, the mechanical seals are mounted on the casing, for example, with studs, and on the shaft with a one-sided collet, clearance-free clamp connection with a conical sleeve and screws; at the end of the pump assembly, the final assembly of the bearing assemblies is carried out on the assembled pump housing using tapered shrink sleeves between the bearings and the shaft and the installation of radial clearances between the rotor and the pump housing, including slotted seals, due to the reuse of removable conical pins between the bearing housing and pump.

At the final connection of the cover and the pump casing, it is possible to use a liquid monomer gasket - anaerobic sealant, with the expectation of the complete polymerization of the sealant under pressure and in the absence of air.

The sealant is polymerized in the absence of air between the gapless metal surfaces, compressed by the forces of tightening the studs. The initial liquid monomer is transformed into a sealant polymer from compression force, but without air, for 1 ... 2 days and then reliably holds the joint seal under operating conditions of high pressure drops.

List of drawings

Figure 1 is a General side section of a pump with a rotor.

Figure 2 - rolling bearing on one side of the rotor console.

Figure 3 - rolling bearing on the other side of the rotor console.

The implementation of the invention

In the figures in the general numbering of the positions, the following significant units and details are enlarged. The most significant components and parts of the pump are enlarged: cast housing 1 with two half-spiral inlets and a double-spiral outlet and molded cover 2 of the pump housing (with a common horizontal plane of the connector along the common central plane of symmetry of the holes for the pump rotor), the pump rotor from balanced and machined shaft 3 and impeller 4, double-sided collet clamping device 5 of the impeller on the shaft, two shaped sleeves 6 on the shaft for forming the flow part of the pump, mechanical seals 7, one-way collet clamps devices 8 mechanical seals on the shaft, two different rolling bearings: spherical double-row roller bearing 9 and toroidal roller bearing 10, tapered shrink sleeve 11, 12 for bearings with an axial section, housings 13, 14 of the tubular type of bearing units (cantilever bearings), lubrication system and bearing seals, sets of fasteners (screws, bolts, nuts, studs, removable conical pins with threaded ends).

Compared to plain bearings, rolling bearings have the following advantages:

1) small moments of friction forces and, as a result, low heat generation; a small dependence of the moments of friction forces on the speed of rotation of the rings; significantly lower moments of resistance to rotation during start-up;

2) less lubricant consumption and less maintenance requirements;

3) low consumption of non-ferrous metals and lower requirements for material and heat treatment of shafts;

4) the possibility of reducing the length of the shaft, and therefore, increasing its rigidity and reducing vibration activity.

Analysis of the design features of the rotor of the main pumps and its bearings showed that the distance between the bearings is quite large (about 1500 mm), therefore it is very difficult to achieve high accuracy of coincidence of the axes of the holes in the pump housing for mounting bearings. Usually there is a mutual displacement of the axes of the holes in the pump housing for mounting bearings. It is necessary to fix the position of the rotor shaft relative to the pump casing against axial displacements while making it possible to compensate for the mutual displacement of the rotor shaft supports when the rotor shaft length changes with temperature. To solve this problem, rolling bearings are suitable: a spherical roller double-row bearing for transmitting radial and axial loads and a toroidal roller bearing for transmitting radial loads with the possibility of mutual axial track displacement.

At the right end of the shaft, the outer ring of a double row spherical roller bearing is fixed from axial displacements in the pump housing. The inner ring of the bearing is connected to the shaft. This installation of the bearing allows transmitting axial force from the rotor to the housing and allows mutual rotation of the bearing rings (shaft journal relative to the housing) up to 2 °.

At the left end of the shaft, the inner ring of the toroidal roller bearing is connected to the shaft. The outer ring of the bearing is connected to the housing. Due to the design features of the bearing, the left support compensates for changes in shaft length due to thermal deformations. In addition, the bearing design allows mutual misalignment of the rings up to 0.5 °.

The speed of the bearings exceeds the operating frequency n = 3000 rpm.

The use of these types of bearings allows you to compensate for inaccuracies that occur in the manufacture of holes.

The use of these rolling bearings allows to reduce the distance between the bearings of the rotor shaft, reduce the radial clearance in the bearings, change the design of the bearing housings to solid housings, which led to a significant increase in their rigidity, as well as a more rigid connection of the bearing housing flange to the pump housing. Due to the fact that the surface of the inner ring of the bearing is conical and mates with a conical screed sleeve, it is possible to separately assemble the bearing assembly as a whole, followed by installing the bearing housing assembly on the end of the rotor shaft.

The type of bearings is selected for reasons of ensuring minimum clearance in the bearings and achieving minimum vibration during pump operation. When designing the rotor shaft, special attention was paid to increasing its bending stiffness and fatigue strength. For this, the shaft supports were extremely close along the axis. Hubs are strained on the shaft in the form of channels, grooves, keyways, and others were either excluded, or their number was minimized.

For reliability of fixing the connection of the cases, the taper of the removable conical pins is small, as a rule, 1:50. To remove the pin, use its threaded end.

The conical coupling sleeves of the rolling bearings are provided with an axial section to increase the bending flexibility of the sleeve body.

Detailed installation of the pump

Before mounting the pump, boring with a boring bar on the boring machine of the holes in the housings from one installation (when boring the indicated holes, empty bearing housings should be fixed to the pump housing with screws and bolted in pairs of removable conical pins).

Next, connect the rotor shaft to the impeller using a double-sided color clamping connection with tapered bushings and screws. The position of the impeller relative to the shaft is ensured by means of a device in the form of a pipe of an exact measured length with a disk and with screw holes at the end. When mounting the impeller, put the pipe on the shaft until the disk stops against the shaft end and fasten it to the shaft end with a screw through the hole in the disk. Tighten the screws of the collet connection in three bypasses with moments of 0.3 Tzat., 0.7 Tzat. and tzat.

From the side opposite to the main screws of the collet connection, install the false screws for connecting the impeller to the shaped sleeve.

Install the shaped bushings on both sides of the impeller, fix them with nuts and lock the nuts.

Lower the shaft with the rings (centering gaskets) previously mounted on it into the pump housing and install the rings in the grooves of the housing.

By shifting the shaft along the axis, to achieve equality of the gaps between the impeller and the rings, insert technological pads (gauges) into these gaps for axial fixing of the shaft relative to the pump casing.

Separately, assemble two bearing units on the mounting table. When assembling the bearing assembly with a spherical double-row roller bearing, insert the bearing into the bearing housing and fasten it with a false cover. Similarly, assemble another bearing assembly with a toroidal roller bearing.

On both sides of the rotor shaft, put on oil disks, brass sealing sleeves (may be with screw seals for reliability) and expansion rings (not shown in the figures).

Slide the bearing assembly onto the shaft, insert the tapered sleeve (from the bearing kit) into the bearing and fasten it with a nut. Install the screws to connect the bearing housing to the pump housing. Turning these screws “by hand” and using mounting gaskets, achieve parallelism of the mating planes of the bearing and pump housings. Measure with a feeler gauge the clearance between the mating planes of the bearing and pump housings. After dismantling the bearing assembly, remove the ring and reduce its thickness by the amount of clearance, which will allow for the final assembly to provide an adjusted clearance between the bearing planes of the bearing and pump housings close to zero.

Remove process gaskets from axial (side) clearances.

Install the pump cover on the pump housing. To do this, after lubricating the contact surfaces of the joint with a liquid gasket (anaerobic sealant-monomer), gently lower the pump cover onto the pump casing, install the pins and fix it on the casing, tightening the nuts in several rounds. Make sure that when lowering the cover, the protrusions of the rings are in the mating grooves of the pump cover. Leave the structure alone for a time sufficient to cure the sealant.

Mount the mechanical seals by installing them so that one of the holes for flushing the mechanical seal faces the upper hole in the pump cover. Secure the mechanical seal on the pump housing with studs and on the shaft axially with a one-way clamp collet. Remove the clips from the mechanical seal springs.

Install the bearing assembly on the shaft, having previously put on the ring, sleeve and expansion ring (not shown). Install a conical shrink sleeve between the bearing and the shaft, tighten the nut with the rated torque and lock it. Tighten the screws “by hand” and, using the mounting screw, align the holes for the pins in the bearing housing with the counter holes in the pump housing. Install the taper pins, tighten and lock the screws.

Remove the cover and place the cover in its place. By choosing the thickness of the gasket, to ensure the absence of axial play of the bearing relative to its housing.

When installing a support with a toroidal roller bearing, the fit of the flanges of the bearing housing and pump will be ensured by the axial mobility of the rings of the roller bearing. But to optimize the conditions of its operation, it is necessary to combine the planes of the ends of the outer and inner rings, which should be ensured by the selection of the thickness of the expansion ring (not shown). To do this, install and fix the bearing assembly on the pump housing by tightening the bolts “by hand”, install the tapered shrink sleeve in the bearing and tighten the nut. Measure the mutual displacement of the outer and inner rings of the bearing and correct the thickness of the expansion ring by the value of this displacement. After that, finally install and secure the bearing assembly.

Check freedom of rotation of the shaft in the assembled pump.

Pump assembly complete. If necessary, bearings and mechanical seals of the shaft rotor can be replaced without disconnecting the cover and pump housing.

An example of assessing the benefits of a method for improving pump performance

Preliminary tests of prototypes of the pump and expert estimates showed the following relative values of the impact of the proposed technical solutions, primarily on the reduction of pump vibrations, presented in the table.

Table of technical solutions to reduce vibration of pumps type NM 1250 ... 10000

As a result, the characteristics of the pump will be significantly improved (its vibration activity is significantly reduced, the resource is increased), and therefore, the main objective of the invention is fulfilled.

Claims (5)

1. A main oil centrifugal pump, consisting of a housing and a housing cover, between the housing and the cover a rotor is installed, consisting of a shaft and a blade impeller, while the pump rotor is installed in cantilever bearings of two types of rolling bearings external to the pump housing: double-row spherical a roller bearing, which receives the axial load of the pump shaft, and a “floating” toroidal roller bearing, both bearings are mounted on the shaft on tapered shrink sleeves with an axial section. 2. The pump according to claim 1, in which the impeller is mounted on the shaft by means of a double-sided collet clamping device with tapered bushings and screws, and the mechanical seals of the rotor are mounted on the shaft by means of single-sided collet clamping devices with tapered bushings and screws, said clamping devices are a combination of two coaxial rings with conical working surfaces with the possibility of displacement of the rings using clamping screws along the axis of the shaft relative to each other with the shaft clamp. 3. The pump according to claim 1 or 2, in which all the connections of the housings are fastened, including pairs of removable conical pins with threaded ends. 4. The method of improving the characteristics of the pump according to claim 1 by means of its high-precision and practically clearance-free assembly, namely: before assembling the pump in the molded pump housing and in the molded cover of the pump housing, baseline grinding of the landing surfaces of the "paws" of the pump housing and the connector planes is made - the general horizontal the plane of the housing and the cover and the vertical mating planes around the holes for the rotor shaft for mounting the housing of the bearing units; for boring from one installation on the boring machine, holes for rings for adjusting axial clearance of the rotor in the housing, holes for slotted seals of the impeller and holes for bearings in the housing of the bearing assemblies, pre-installation of the boring bar with boring through the empty housing of the bearing assemblies cutters adjustable flights and then make the connection of the pump housing and cover with studs and two removable conical pins with threaded ends horizontally Flax plane of the connector and its connection empty shells bearing assemblies of screws and removable pairs of conical pins with threaded ends along vertical planes connectors with the housing and the cover of the pump housing; after boring the holes from one installation, disconnect all cases and covers with the removal of all removable conical pins; regardless of the boring operation, from one installation, the pump rotor is assembled from the shaft, the impeller and two shaped sleeves on the shaft participating in the formation of the pump flow path, using a double-sided collet clamping connection with conical bushings and screws and using a precision measuring device in the form of a pipe lengths for pinpointing the location of the impeller on the shaft, then install and mount the shaped bushings on both sides of the collet chuck; then the rotor is installed with the axial clearance adjustment rings previously mounted on its shaft in the pump housing without a cover and the clearances are aligned between the impeller and the rings with axial shaft fixing relative to the pump housing, for example, using technological gaskets; regardless of the installation of the rotor in the pump housing, two bearing assemblies with a spherical double-row roller bearing and a "floating" toroidal roller bearing are separately assembled; followed by adjusting the installation and then dismantling the bearing assembly with a spherical double-row roller bearing on the rotor shaft and on the pump housing to ensure that the clearance between the mating planes of the bearing housing and the pump housing is practically zero due to a corresponding reduction in the thickness of the expansion ring; before final fastening of the pump cover to the pump casing, using studs and conical pins, fixing technological pads are removed from the axial clearances of the shaft relative to the casing; after attaching the pump cover to the pump casing, the mechanical seals are installed between the rotor shaft and the assembled pump casing, the mechanical seals are mounted on the casing, for example, with studs, and on the shaft with a one-sided collet, clearance-free clamp connection with a conical sleeve and screws; at the end of the pump assembly, the final assembly of the bearing assemblies is carried out on the assembled pump housing using tapered shrink sleeves between the bearings and the shaft and the installation of radial clearances between the rotor and the pump housing, including slotted seals, due to the reuse of removable conical pins between the bearing housing and pump. 5. The method according to claim 4, in which at the final connection of the cover and the pump casing, a liquid monomer gasket is used - an anaerobic sealant, with the expectation of the complete polymerization of the sealant under pressure and in the absence of air.

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