RU2484304C1 - Main electric pump unit with attachments to frame with use of built supports, and method for improvement of unit characteristics - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: unit includes the main pump and an electric motor, which are mounted on a frame. Their shafts are connected through a coupling to a detachable intermediate shaft. Attachments of the pump and the electric motor to common or separate frames are made using high-accuracy built supports adjustable as to height and self-adjusting as to an angle. Attachment surfaces of the pump legs are lifted to the level of common central axis of supply and discharge branch pipes of the pump. Shafts of the pump and the electric motor are connected by means of a compensating double coupling to flexible discs.

EFFECT: creation of the main electric pump unit with improved technical and economic characteristics, and namely with reduced noise and vibrations, improved reliability, service life and efficiency.

4 cl, 5 dwg

Description

Technical field

The invention relates to electric pump units, in particular, with trunk oil horizontal centrifugal pumps.

State of the art

A known frame is a vibration-damping foundation pump unit (RF patent No. 103584, IPC F04D 29/00, publ. 04/20/2011, patent holder - LLC "NKMZ") containing self-aligning mounting elements (or, in terminology, more correct in essence, are supplied supports) between the mounting surfaces of the frame and the “feet” of the unit.

However, only the frame of the pumping unit is considered, and not the entire electric pumping unit, consisting of a horizontal centrifugal pump, a drive motor, the shafts of which are connected by a coupling, and one common or two separate frames (called foundation or mounting frames) with in-line supports for the pump and motor paws , therefore, the features of the interaction of the listed main components of the unit are not taken into account.

Also known is a centrifugal electric pump unit (RF patent No. 95043, IPC F04D 1/00, F16D 3/50, publ. 06/10/2010), in which the pump and electric motor are mounted on a common foundation plate (frame), their shafts are connected by an elastic coupling, between the half-couplings of which a removable spacer (or an intermediate shaft) is installed for assembling and disassembling the unit without removing the electric motor from the foundation plate under conditions of tight connection (usually a welded joint) of the pump casing with the supply and outlet pipelines.

In the unit, only the issue of the removable spacer of the coupling for assembling and disassembling the pump of the unit without removing the electric motor from the plate is considered, which, according to the authors, will allow not to disturb the alignment of the impeller and electric motor shafts, and, therefore, will avoid premature bearing wear, overheating of the electric motor, increase noise and vibration. At the same time, nothing is said about another issue, which is also crucial for ensuring the alignment of the pump and motor shafts - the rigid, clearance-free mounts of the pump and motor on a common foundation plate (frame), apparently immediately considering these mounts ideal.

However, in a comprehensive statement of the problem of ensuring the alignment of the shafts of the electric pump unit in order to avoid premature bearing wear, motor overheating, and noise and vibration, it is necessary to take into account the issues of rigid clearance-free mountings of the pump and electric motor on one common or two separate frames and the dismountability of the compensating coupling.

As an analogue of the method of improving the characteristics of the unit through its high-quality assembly on the frame, taking into account various alternatives, a method for mounting a turbocompressor unit is known (RF patent No. 2263247, IPC F16M 5/00, F16M 9/00, F01D 25/28, publ. 10.27.2005) consisting of a turbocompressor group (functional analogue of the pump) and a supercharger (functional analogue of the electric motor), as well as their frames (installation and transport-technological) with supporting surfaces. The disadvantages of this method are the use of complex and laborious methods of assembly and installation of the unit on the frames and the use of fitting gaskets (or plates of measured thickness).

Also, the existing traditional methods of installation and alignment alignment of the shafts of the main pumping units are based on a change in the position of the support "legs" using metal plates of measured thickness. Such plates have the following disadvantages: - the impossibility of accurate alignment due to the measured thickness of the plates; - low rigidity of the package of plates (as a rule, use two or more plates); - the inability to level the angular distortions between the equipment and the base, which causes additional misalignment, vibration of the pump and motor shafts and overheating of the bearings; - expensive machining of the base (frame). The inevitable negative consequences are not only an increase in energy losses and the duration of installation work, but also a reduction in the resource or overhaul mileage of electric motors and pumps. Traditional adjustment methods take a lot of time and cannot, over the life of the unit, provide requirements for installation accuracy and the possibility of installation in a short time.

Disclosure of invention

The main general objective of the invention is the creation of a main electric pump unit with improved technical and economic characteristics, specifically with reduced noise and vibration, increased reliability, resource and efficiency through a series of structural and technological improvements combined in a single inventive concept in the places where the pump and electric motor are attached to a common or separate unit frames in conjunction with the use of the original, mounted between the shafts of the pump and the electric motor contactor with the ability to quickly dismantle the compensating dual coupling by removing the intermediate shaft.

The technical effect is achieved by the fact that:

1) the main electric pump unit contains a main pump and an electric motor mounted on the frame, their shafts are connected by a coupling with a removable intermediate shaft.

Wherein:

2) high-precision approach bearings, adjustable in height and self-adjusting in angle, are used with practically clearance-free rigid installation of the pump and electric motor on a common or separate frames;

3) the mounting surfaces of the pump “paws” are raised to the level of the common central axis of the pump inlet and outlet pipes to exclude the formation (when the values of the resulting arms are practically zero) of the resulting tipping moments around the central axes of the pump inlet and outlet pipes from the effects of the pumped liquid flows in the pipes on the mountings “Paws” of the pump to the frame, while this also unloads the welds (or flange mounts) of the pipes and pipelines;

4) the original dual coupling with flexible disks was also used, compensating for the inevitable installation and operational errors of the connection of the pump and motor shafts.

The high-precision inlet support consists of three washers, the two lower washers are connected by a thread that allows you to change the height of the inlet support, the middle and upper washers have mating spherical surfaces with the same radius of curvature, these spherical surfaces in a joint connection make it possible to seamlessly connect non-parallel surfaces of the parts to be joined and compensate for the angular deviation between them; all washers have a common axial hole for the mounting bolt and nut for the final bolt pressure of one part to another through a common through hole in the support and both parts, in this case, “paws” to the frame. The two lower washers have non-through radial holes for the possibility of using levers when adjusting the height of the support.

The compensating twin coupling consists of a combination of two identical couplings connected by an intermediate hollow shaft. In each coupling between its two half-couplings a flexible hardened steel disk (or a set (package) of disks) is installed. To unload the disks in the couplings, spherical joints in the form of spherical double-row rolling bearings are installed. Each of the two couplings contains the same even number of clamp mounts of the disc sets. Opposite directional mount bushes are located on the flanges of the coupling halves through one uniformly and at a uniform radial distance from the common central axis of rotation of the couplings and shafts, the opposite directional clamping fasteners of the sets of floppy disks of both couplings are coaxial.

A way to improve the characteristics of a main electric pump unit by mounting the unit includes mounting the pump and electric motor on a common or separate frames using adjustable high-precision feed legs in the following sequence of steps: - installing a common frame or individual frames on the foundation, verifying the horizontal position of their supporting surfaces at two levels and final fixing frames on the foundation; - a fitting installation of the pump and / or electric motor on a common frame or on separate frames on the supplied supports; - drilling of common through holes in bearings, “paws” and corresponding mounting surfaces of the frame and preliminary installation of mounting bolts in made through holes, - welded or flanged connection of pump nozzles with pipelines; - adjustment and final installation of all supplied supports under the pump and electric motor with the simultaneous use of a laser device for accurate alignment of the alignment of the pump and electric shafts; - final tightening of the mounting bolts of the supports; - connection of coaxially exposed pump and motor shafts by means of mounting a compensating twin coupling with an intermediate shaft.

List of drawings

Figure 1 is a General side view of an electric pump unit with feed legs.

Figure 2 is a view of a pump with attached pipelines and with supply supports between the extension of the frame and the "paws" of the pump.

Figure 3 is a perspective view of a modernized main pump.

Figure 4 - approach support in a lateral section on an enlarged scale.

5 is a longitudinal section through a compensating coupling with flexible disks.

The implementation of the invention

Positions in the continuous numbering in the figures: 1 - pump; 2 - electric motor; 3 - compensating double coupling; 4 - frame; 5 - extension of the frame; 6 - "paws" of the pump; 7 - pump nozzles with attached pipelines; 8 - input supports; 9 - the upper washer of the input support with a spherical bearing surface (base); 10 - an intermediate screw threaded washer with a reciprocal spherical surface; 11 - lower washer with a mating threaded hole; 12 - the first and second identical double clutch couplings; 13 - flexible disks of couplings; 14 - fastening of floppy disks to flanges of couplings; 15 - spherical hinges-bearings of couplings; 16 - removable intermediate shaft between the couplings.

The presence of a “soft paw” - the fourth point of contact of the pump casing (and for an electric motor with 6 “paws” - with 3 “soft paws”) with the frame - is almost inevitable from the geometry of the plane. In addition, the planes of the supporting surfaces of the plates on the frame and the “paws” on the pump casing are inclined relative to each other, which is further aggravated by the stress conditions of imperfect joints (usually welded) of the pump nozzles with pipelines. All this reduces the quality of pressing the pump housing to the frame. Landing on the frame ultimately turns out to be non-rigid, which leads to the generation of additional vibrations during operation of the electric pump unit, which negatively affects the amplification of noise around the working unit, the premature wear of its bearing units, and increased temperature conditions. Errors in the manufacture of installation surfaces and the non-rigid joint of the connection of "soft paws" with the frame reduces the accuracy of the installation of the shafts of the unit. The result is misalignment. Misalignment refers to the linear and (or) angular displacement of the shaft axes. The rotor shaft, seals and bearings are additionally loaded with radial and axial forces and bending moments, depending on the size and type of alignment of the shafts. Misalignment causes a redistribution of load on individual bearings, and thereby affects the vibration of the unit. At the same time, overloading the bearings can lead to bearing accidents. With the redistribution of loads on the bearings, the critical rotational speeds change, and therefore, the possibility of increased resonant vibrations. The misalignment of the shafts is the cause of more than 50% of failures of rotating mechanisms, leading to an increase in downtime of equipment and an increase in the cost of its operation. Misalignment also causes an increase in the load on individual parts of the unit, accelerating their wear and increasing energy consumption.

The high-precision approach bearing proposed for use in the unit consists of three washers, the two lower washers are connected by a thread, which allows changing the height of the approach bearing, the middle and upper washers have mating spherical surfaces with the same radius of curvature, these spherical surfaces in a joint connection allow practically unobtrusively connecting non-parallel surfaces connected parts and compensate for the angular deviation between them; all washers have a common axial hole for the mounting bolt and nut for the final bolt pressure of one part to another through a common through hole in the support, “foot” and frame. The two lower washers have non-through radial holes for the possibility of using levers when adjusting the height of the support.

This self-leveling structure is adapted to eliminate the angular misalignment that occurs between mounted surfaces. The elements compensate for up to 4 ° skew between the machine and the frame without expensive base treatment or additional work on installing polymer gaskets. Self-alignment in combination with height adjustment eliminates the risk of the appearance of a "soft foot" from the moment of installation and throughout the life cycle of the equipment. Low-profile approach supports are an economical solution for carrying out repairs with fixed machines, for the installation of which other types of supports were previously used. All parts of the support are made with a high degree of accuracy and from high-strength steels. The advantage of the supports is the absence of aging, as in the case of rubber or polymer gaskets. This eliminates the occurrence of a mismatch in equipment, characteristic when using other supports, and provides adjustable throughout the life of the unit. The use of height-adjustable, angularly self-aligning and reusable feed supports allows to increase the productivity and accuracy of installation and alignment of pump units without a fundamental change in the design of the unit itself.

To verify the alignment of the connected pump and motor shafts, one can use a commercially available, specialized for this task, non-contact laser measuring device manufactured by SKF (Sweden).

After alignment of the shafts, they are connected by a sleeve. In the original compensating twin coupling, the combination of two identical couplings connected by an intermediate hollow shaft allows connecting the pump and drive motor (electric motor) shafts, which inevitably have shaft alignment errors that appear during installation and operation of the unit, not only angular, but also radial. A responsible part of each coupling is a flexible steel disk (or a set (package) of disks), experiencing cyclic bending and torsion deformations in the presence of angular displacement of the coupling halves of a rotating coupling. However, when two such couplings are connected by an intermediate hollow shaft, a double clutch is formed, which, in addition to angular, also exhibits radial compliance, which, for example, allows radial displacements of the motor and pump shafts relative to each other. For unloading thin hardened steel flexible disks, spherical joints (or articulated bearings) (in the form of spherical double-row rolling bearings) installed in the couplings are provided. These hinges are designed to unload the coupling flexible disk from additional loads caused by the imbalance (imbalance) of the intermediate hollow shaft connecting the couplings. Also, for the uniformity and uniformity of the transferred loads on the disks, each of the two couplings contains the same even number of clamp fasteners of the sets of disks. The fasteners consist of high-strength threaded bushings with counterclamping screws and clamping washers. One half of the fastener bushings is pressed into the flange of one half-coupling and directed through the corresponding holes of the floppy disk set into the corresponding holes of the second half-coupling flange for threaded connections with the corresponding clamping screws, and the second half of the bushings is vice versa: pressed into the second half-coupling flange and directed through the corresponding holes of the set a floppy disk into the corresponding holes of the flange of the first coupling half for threaded connections with the corresponding screws of the clamping fasteners . Opposite directional mount bushes are located on the flanges of the coupling halves through one uniformly and at a uniform radial distance from the common central axis of rotation of the couplings and shafts, the opposite directional clamping fasteners of the sets of floppy disks of both couplings are coaxial.

The way to improve the characteristics of the unit (primarily vibration and noise) by means of high-precision and maximum clearance-free installation of the unit includes the following sequence of methods: - installation of a common frame or individual frames on the foundation, alignment of the horizontality of their supporting surfaces at two levels and the final fixing of the frames on the foundation; - fitting room (or "gain") installation of the pump and / or electric motor on a common frame or separate frames on the supplied supports; - drilling of common through holes in bearings, “paws” and corresponding mounting surfaces of the frame and preliminary installation of mounting bolts in made through holes, - welded or flanged connection of pump nozzles with pipelines; - adjustment and final installation of all supplied supports under the pump and electric motor with the simultaneous use of a laser device for accurate alignment of the alignment of the pump and electric shafts; - final tightening of the mounting bolts of the supports; - connection of the pump and electric motor shafts coaxially set and spaced apart from each other to install the coupling by installing a compensating twin coupling: first one coupling on one shaft, then the second on the second shaft and at the end between them installing an intermediate shaft with connecting its flanges with coupling flanges.

The final installation of the supplied supports and the final tightening of the mounting bolts is performed with torque levers and wrenches to the calculated values of the tightening torques, depending on the dimensions of the parts.

As a result, the clearance-free installation of the pump and motor paws on a common frame or separate frames using the supplied supports with the complete elimination of the soft paws effect will significantly increase the stiffness of the coupling between the pump casing and the electric motor with the frame, and, together with the use of a compensating coupling, will increase the shaft alignment pump and electric motor, which will positively affect the reduction of vibration, noise, temperature conditions of operation of the bearing assemblies of the electric pump unit.

To conclude the description, we note that preliminary tests of prototypes of modernized NKMZ LLC main pumping units with pumps of the NMPP 1250 ... 10000 type and expert evaluations gave the following relative values of the impact of the proposed supply legs and compensating couplings on reducing the vibration of the pump of the electric pump unit, presented in the table .

Claims (4)

1. A main electric pump unit containing a main pump and an electric motor mounted on a frame, their shafts are connected by a coupling with a removable intermediate shaft, characterized in that the fastening of the pump and electric motor to a common or separate frames is made using high-precision adjustable height-adjustable and self-mounted angle supports, mounting surfaces of the pump “paws” are raised to the level of the common central axis of the pump inlet and outlet pipes, a compensating twin coupling is also used and floppy disks. 2. The assembly according to claim 1, characterized in that the high-precision input support consists of three washers, two lower washers are connected by a thread that allows changing the height of the input support, the middle and upper washers have mating spherical surfaces with the same radius of curvature; all washers have a common axial hole for the mounting bolt with nut for final clamping of the “paw” to the frame with a bolt and nut through a common through hole; the two lower washers have non-through radial holes for the possibility of using levers when adjusting the height of the support. 3. The assembly according to claim 1, characterized in that the compensating twin coupling consists of a combination of two identical couplings connected by an intermediate hollow shaft, in each coupling between its two half-couplings a flexible hardened steel disk (or a set (package) of disks) is installed, for unloading discs in the couplings have spherical joints in the form of spherical double-row rolling bearings, each of the two couplings contains the same even number of clamp mounts of the disc sets, the opposite directional mount bushes are located on Lanza through one of the coupling halves, uniformly and on a uniform radial distance from the common central axis of rotation and the coupling shaft, wherein the oppositely directed sets of clamping fastening floppy disks both couplings are coaxial. 4. The method of improving the characteristics of the unit according to claim 1 by mounting the unit, including mounting the pump and electric motor on a common or separate frame with mounts to the frame using adjustable high-precision feed legs, including the following sequence of methods: installing a common frame or separate frames on the foundation, alignment horizontality of their supporting surfaces in two levels and the final fixing of frames on the foundation; a fitting installation of the pump and / or electric motor on a common frame or on separate frames on supplied supports; drilling common through holes in the supports, "legs" and the corresponding mounting surfaces of the frame and pre-installation of mounting bolts in the made through holes, welded or flanged connection of the pump nozzles with pipelines; adjustment and final installation of all supplied supports under the pump and electric motor with the simultaneous use of a laser device for accurate alignment of the alignment of the pump and electric shafts; final tightening of the mounting bolts of the supports; connecting coaxially exposed and spaced apart pump shafts and an electric motor by mounting a compensating twin coupling with an intermediate shaft.

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