RU2449175C1 - Centrifugal pump with prestressed elastomer elements of flow part (versions) - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: pump design includes new structural elements: circular springs 5, 6, which develop continuous compression stress, increasing strength and wear resistance of polyurethane in polyurethane elements of the pump exposed to highest wear. The feature of a combination to strengthen polyurethane: a steel circular spring 5, 6 - a polyurethane web consists in the fact that energy of the spring 5, 6 is transferred to polyurethane for its elastic or highly elastic deformation with accompanying strengthening, which takes effect in case of abrasive exposure of polyurethane. In the pump the following components are made of prestressed polyurethane - linings 3 of a body 1 and a cover 2 of a pump, impeller discs 9, a front armoured disc 4.

EFFECT: due to high wear resistance of stressed polyurethane the resource of pump flow part increases, and stability of its hydrodynamic parameters is ensured.

Description

The invention relates to mechanical engineering and can be used to create pulp centrifugal pumps designed for pumping ore pulps at mining and processing plants.

One of the problems of pulp centrifugal pumps is the rapid wear of the elements (The products that make up the pump are called parts in the technical literature, and the largest of them, such as the impeller, pump housing, etc., are called pump elements. In this case, the largest parts are considered pump: impeller, armored disk, pump lining, etc., for which our name is more characteristic - pump elements) of the pump in contact with the moving pulp saturated with abrasive grains of various grades rocks. Surfaces in the narrow space between the wall of the pump cover and the rotating impeller are also subject to rapid wear due to pulp recirculation.

Centrifugal pumps are known in which in order to prevent wear of metal surfaces they are coated with a layer of polyurethane elastomer.

Closest to the invention is a centrifugal pump with prestressed elastomeric elements of the flowing part, comprising a coiled housing and a lid lined inside with structural elements of a polyurethane elastomer, a polyurethane impeller and a front armored disk, a steel drive shaft with a sealing system, shaft bearings (L. Kondrashov Review of modern slurry pumps, Moscow, Mining equipment, 2005).

However, the resource of polyurethane elements of the flow part of the pump remains insufficient, given that with the wear of polyurethane the cross section of the pulp channel changes and the hydraulic parameters of the pump deteriorate, and the frequent replacement of polyurethane linings is associated with significant material costs.

It is known to increase the strength and durability of thermoplastic polymers by processing them by compression in the solid state (die and sheet stamping, rolling. See Physicochemical Basics of Polymer Processing into Products for Machines and Equipment. Tambov, TSTU, 2005).

The phenomenon of increasing the strength of thermoplastics is based on a change in their internal structure that occurs during plastic deformation under the influence of high pressures. The disadvantages of this method are the need to create complex forms that can transmit high pressure to the adopted configuration of the products, and a partial decrease in the strength properties in the products when removing loads from them.

There is no evidence of the effectiveness of this method for polyurethanes. Studies of the authors of this invention have shown that the strength properties of polyurethanes increase at relatively low constant pressures that create elastic and highly elastic deformations of the polyurethane web and maintain it in tension. The values required for this pressure on the polyurethanes of different grades are 0.5-5 MPa.

The objective of the invention is to increase the wear resistance of pump elements made of polyurethane, and, accordingly, increase the overhaul life of the pump while maintaining the constancy of its hydraulic parameters.

The technical result is achieved due to the fact that in a centrifugal pump with prestressed elastomeric elements of the flowing part, containing a coiled housing and a lid, lined inside with structural elements from a polyurethane elastomer, a polyurethane impeller and a front armored disk, a steel drive shaft with a sealing system, shaft bearings, according to the invention according to the first embodiment, in the central part of the polyurethane web of the housing lining element on the drive side to deform From this point, and creating compression stress in it, an annular compression spring in a compressed state (hereinafter referred to as a compressed annular spring) made of hardened spring-spring steel and developing a pressure of 0.5-5 MPa on polyurethane is built in concentrically with the central hole in the web, and for radial movement a flange encircling the central hole in the polyurethane web of the lining element, a recess is provided in the surface of the rear disk of the impeller of the pump in the form of an annular rectangular groove into which the collar enters.

At the same time, concentric ring springs can be integrated concentrically with a central hole in the web into the central part of the polyurethane web of the body lining.

A ring made of rolled steel (hereinafter referred to as a thrust ring) can be integrated concentrically with ring springs into the polyurethane fabric of the housing lining element, at its periphery.

1-3 compressed ring springs located concentrically in the central part of the armored disk, developing a compression pressure of polyurethane of 0.5-5 MPa, and one steel thrust ring located on the periphery of the armored disk fabric concentrically with ring springs can be embedded in the polyurethane fabric of the front armored disk.

In the polyurethane sheet of each of the impeller disks in its central part, 1-3 compressed ring springs can be integrated concentrically with central holes in the disks, developing 0.5-5 MPa of the compression pressure of the polyurethane, and one thrust ring located in the peripheral parts of the canvas of each disk.

The technical result is also achieved by the fact that in a centrifugal pump containing a coiled housing and cover, lined with structural elements of polyurethane elastomer, a polyurethane impeller and front armored disk, a steel drive shaft with a sealing system, shaft bearings, according to the invention of the second embodiment, in a polyurethane web of the housing lining element on the drive side is built around the periphery of 1-4 ring tension springs in a stretched state (hereinafter unclamped ring springs), They have a compressive pressure of polyurethane of 0.5-5 MPa.

Moreover, in the central part of the polyurethane web of the housing lining element, a steel thrust ring can be integrated concentrically with ring springs from the drive side.

The technical result is also achieved by the fact that in a centrifugal pump containing a coiled housing and a lid lined inside with polyurethane elastomer elements, a polyurethane impeller, a steel drive shaft with a sealing system, shaft bearings, according to the invention of the third embodiment, in a polyurethane fabric of the lining element of the pump cover concentric concentric annular spring is integrated concentrically with a central hole in the web along the periphery and a thrust ring in the central part.

The technical result is also achieved by the fact that in a centrifugal pump containing a coiled housing and a lid lined with polymer elements inside, a polymer impeller, a steel drive shaft with a sealing system, shaft bearings, according to the invention according to the fourth embodiment of the lining of the casing and lid elements, consist of interconnected by bonding or thermal welding of two layers of polymers with different coefficients of linear thermal expansion in the range of 50-500 %, while a layer, for example, of a polyurethane elastomer, facing the internal cavity of the pump, has a lower coefficient of linear thermal expansion than a layer glued or welded to it from another elastomer or thermoplastic.

Thus, new structural elements have been introduced into the pump device: annular springs that create a constant voltage in the most worn polyurethane pump elements, due to which their strength and wear resistance are increased.

For the formation of the so-called prestressed polyurethane, constant stresses are created in its web, causing elastic or highly elastic deformations of the polyurethane.

As shown by tests conducted by the authors of this invention, the strength and wear resistance of a noliurethane, which is in a constantly compressed state, begin to increase significantly already when it is deformed by 2-3%, when the load is removed, the achieved strength indicators are reduced.

A feature of the polyurethane reinforcing combination: a steel spring polyurethane sheet is that the spring energy is transferred to the polyurethane for its elastic or highly elastic deformation and the concomitant hardening, which is triggered by abrasive influences on the polyurethane. As the polyurethane is worn out and its web is thinned, deformation of the polyurethane by a spring and stress in it automatically increase, which helps to increase the life of the pump elements. Since the pump elements made of polyurethane have a rounded shape, an annular spring shape is most effective to achieve a uniform pressure distribution in the polyurethane web.

In the proposed pump design, compression of the polyurethane fabric of the pump elements by ring springs was first applied. In the polyurethane fabric of each of the elements, from 1 to 2-4 ring springs compressed or extruded by external forces are integrated independently or in combination with closed steel rings, which we called “thrust rings”, in connection with their functions, to prevent the spread of polyurethane deformation outside these rings .

Compressed annular springs, the internal stress of which is aimed at unclenching the arcs of the ring, are placed in the central part of the polyurethane webs, and uncompressed, working on compression - on the periphery.

The most effective is the combination of ring springs integrated into the polyurethane web with thrust rings, which are arranged concentrically with compressed ring springs around the periphery, and when opened, in the central part of the polyurethane webs. In both cases, when unloading or compressing the annular springs, the polyurethane web is compressed and deformed in the plane between the annular spring and the thrust ring. The steel thrust ring, preventing the spread of deformation outside the ring, thereby preserves the external shapes and dimensions of the prestressed canvas.

Strengthening the compressive effect on polyurethane is achieved by increasing the number of concentrically mounted annular compressed or decompressed springs with one thrust ring or by replacing it with a compressed or unpressed spring of the opposite action to the other springs.

Figure 1 shows a General view of a centrifugal pump of the proposed design.

Figure 2 is a front view of a prestressed element of the lining of the pump housing.

Figure 3 is a section aa in figure 2.

In Fig.4 is a General view of the inner annular spring in the expanded state.

Figure 5 is the same in a compressed state.

Figure 6 - fastened ends of the compressed annular spring.

In Fig.7 is a front view of a section of a prestressed element of the lining of the pump housing with an external open ring spring.

On Fig - section aa in Fig.7.

Figure 9 is a General view of the outer annular spring.

Figure 10 is the same in working condition.

11 is a front view of a pre-stressed element of the lining of the housing with the location of the compressed inner ring spring and the outer thrust ring when combined in one polyurethane fabric.

On Fig - section aa in Fig.11.

In Fig.13 - the location of the compressed annular springs with an increase in their number to 2.

On Fig - the same, with an increase in their number to 3.

On Fig - the location of the annular compressed spring and thrust ring in the armored disk.

In Fig.16 is a section aa in Fig.15.

On Fig - Central section of prestressed polyurethane pump elements.

On Fig - section aa in Fig.17.

On Fig - sectional modification of the proposed centrifugal pump.

In Fig.20 is a front view of a prestressed element of the lining of the cover.

On Fig - section aa in Fig.20.

On Fig - element of the lining of the pump housing from two layers of polymers glued or welded together.

On Fig - section aa in Fig.22.

Figure 1 shows a General view of a centrifugal pump of the proposed design. The pump consists of a housing 1, a cover 2, a prestressed polyurethane lining 3 of the housing 1, a front armored disk 4 of a prestressed polyurethane, internal compressed ring springs 5, 6, respectively, a lining of the housing 1 and the front armored disk 4, the outer thrust rings 7, 8, respectively, of the lining 3 case 1 and the front armor plate 4, the impeller 9 with disks of prestressed polyurethane, shoulder 10, encircling the Central hole 19 (Fig.1, 2) of the lining 3 of the housing 1, an annular rectangular ditch and 11 in the surface of the disk of the impeller 9, the internal compressed ring springs 12 in the disks of the impeller 9, the thrust steel rings 13 in the disks of the impeller 9, the sealing system 14 of the drive shaft 16, the bed 15, the bearings 17 of the drive shaft 16, the suction pulp pipe 18 .

The pulp enters through the suction pipe 18 into the flow part of the pump, where it is accelerated by the blades of the impeller 9 and fed into the pump outlet. The prestressed polyurethane in the flow part ensures, due to its high wear resistance, the constancy of the parameters of the movement of the pulp.

Figure 2 and 3 shows a front view and a section of a prestressed element of the lining 3 of the pump housing 1, which shows the location in the element sheet directly at its central hole 19 of an internal compressed annular spring 5, working on compression, while compressing the polyurethane outside the ring springs 5.

The compressed annular spring 5 is made of a rolled steel spring steel open at _^1/4 - _^1/3 ring closed external forces to the joint ends.

A general view of the inner annular spring 5 in the expanded and compressed states is shown in Figs. 4-6, where Fig. 4 shows an open spring ring made of rolled steel from spring-spring steel, and Fig. 5 shows an open spring ring driven by external forces in the compressed state, in which the ends by external forces are reduced to contact with each other - Fig.6 and fastened with a thin rod 21, threaded through the holes 22 in the rod 20 of the spring 5.

In the manufacture of a prestressed polyurethane element, the compressed spring ring is placed in the mold and filled with molten polyurethane. After passing through all phases of the formation of the polyurethane product and its cooling, the rod 21 is removed from the holes 22, the annular compressed spring 5 is brought into a state of expansion, compressing the polyurethane fabric outside.

7, 8 are a front view and a section of a pre-stressed element of the lining 3 of the pump housing 1, which shows the location of the external expanded ring spring 23, which operates to compress the polyurethane web located inside the spring ring 23.

The external expanded annular spring 23 is a ring made of spring-spring steel rolled, extruded by external forces to a predetermined angle. A general view of the spring annular spring 23 is shown in Figs. 9, 10. The manufactured annular spring 23 is shown in a compressed state — Fig. 9 and brought into working condition — Fig. 10, in which the ends are externalized by a certain angle, and in the gap between them are inserted two bent plates 24 with holes in which rods 25 are inserted, holding the annular spring 23 in an unclenched state.

Compression of a polyurethane web by an expanded ring spring 23 is carried out in the plane of the circle bounded by it after removing the rods 25 from the holes of the plates 24. The embedding of the expanded ring spring 23 in the polyurethane fabric of the product is similar to the integration of a compressed ring spring 5.

11, 12 shows a front view and a section of a prestressed element of the lining 3 of the housing 1, which shows the location of the inner compressed annular spring 5 and the outer thrust ring 7 when combined in one polyurethane fabric.

The specified value of the compressive stress of polyurethane is achieved by selecting the appropriate rolled profile and spring-spring steel grade in the manufacture of ring springs 5 or the number of installed springs 5, placing them concentrically between the central hole 19 and the thrust ring 7.

On Fig shows the concentric arrangement of the compressed ring springs 5 when increasing their number to 2, similarly located ring springs when they increase to 3x4-4x (Fig.14).

Similarly, an annular compressed spring 6 and a thrust ring 8 are located in the armored disk 4 (Fig.15, 16).

In another case, an increase in the compressive effect on polyurethane is achieved due to the fact that instead of thrust rings inside and on the periphery, ring springs are installed: compressed in the center, unclenched on the periphery.

In Fig.17 shows a Central section of the prestressed polyurethane elements of the pump: lining 3 and the impeller 9. In Fig.18 is a vertical section aa of the lining 3 of the housing 1 of the pump. The location of the internal compressed annular springs 12 and the external thrust rings 13 in the polyurethane disks of the impeller 9, shoulder 10, encircling the central hole in the lining element 3 of the pump housing 1 and entering into the annular rectangular groove 11 on the surface of the rear impeller 9. The groove 11 is shown following functions. When unclenching the inner annular spring 12, accompanied by the expansion of the Central hole in the polyurethane web 19 (figure 2), the protruding above the web flange 10 moves across the groove 11, without interfering with the unloading of this spring 12. At the same time, the collar 10 included in the groove 11 of the disk , reduces pulp recycling between the rear impeller disk 9 and the element of the prestressed polyurethane lining 3 of the pump.

On Fig shows a section of a modification of the proposed centrifugal pump, in which instead of the armored disk lining 26 of the cover 2 of the pump made of strained polyurethane is used. The pump consists of a housing 1, a cover 2, a prestressed lining 3 of the housing 1, with an internal compressed annular spring 5 and an external thrust ring 7, a lining 26 of the lid 2 with an external expanded annular spring 27 and a thrust ring 28, an impeller 9 with disks of pre strained polyurethane, shoulder 10, encircling the central hole in the liner 3 of the housing 1, an annular rectangular groove 11 in the surface of the impeller disk 9, internal compressed ring springs 12 in the disks of the impeller 9, resistant steel rings TS 13 in the disks of the impeller 9, the sealing system 14 of the drive shaft 16, the bed 15, the bearings 17 of the drive shaft 16, the suction pulp pipe 18.

On Fig and 21 shows a front view and a section of a pre-stressed element of the lining 26 of the cover 2, which shows the concentric arrangement in it of the expanded spring 27 and the thrust ring 28.

Additional open ring springs are located between the thrust ring 28 and the open spring 27 concentrically with them.

As another variant of the mechanism of creating a constant voltage in a polyurethane web, gluing or thermal welding of a polyurethane layer with a polymer layer having a coefficient of linear thermal expansion other than polyurethane is proposed.

When the layers are firmly bonded in the heated state and subsequently cooled in a layer with a lower coefficient of linear thermal expansion, compression stress arises due to greater shrinkage of the layer with a large expansion coefficient at the same cooling temperature for both layers.

On Fig shows a lining element 3 of the housing 1 of the pump from two layers of 29, 30 polymers glued or welded together. The inner layer 29 is formed by a polyurethane elastomer with a lower coefficient of linear thermal expansion, the outer layer 30 is made of polyurethane with a large coefficient of linear thermal expansion. Similarly, the structure of the two-layer element of the lining 26 of the cover 2 of the pump. Compression and tension of the polyurethane layer is achieved with the following manufacturing technology of the two-layer element of the lining 3: first, polyurethane with a high expansion coefficient is poured into the mold, forming the outer layer 30 and processed according to the accepted technology to final cooling. Then, polyurethane with a lower coefficient of expansion is poured from above, forming the inner layer 29, while the external cooled polyurethane layer is heated and expanded. With the subsequent cooling of the two-layer element of the lining 3, the inner polyurethane layer 29 is compressed due to the greater shrinkage of the outer layer 30.

The compression effect is enhanced when combined in the manufacture of two-layer polymer pump elements of polyurethane elastomers, the coefficient of linear thermal expansion of which does not exceed 60-70 units. with other polymers such as fluoroplastic (expansion coefficient 280 units), polyethylene (200 units).

The industrial usefulness of this invention is to increase the overhaul life of the pump while reducing the fluctuation of the hydrodynamic parameters of the pumped pulp, depending on the rate of wear of the elements of the flow part of the pump and the frequency of their replacement.

Claims (9)

1. A centrifugal pump with prestressed elastomeric elements of the flowing part, comprising a coiled housing and lid lined inside with structural elements of a polyurethane elastomer, a polyurethane impeller and a front armored disk, a steel drive shaft with a sealing system, shaft bearings, characterized in that in the central part a polyurethane web of the housing lining element on the drive side with the aim of deforming the web and creating a compression stress in it is integrated concentrically from the center a compression hole (hereinafter referred to as a compressed ring spring) made of hardened spring-spring steel and developing a pressure of 0.5-5 MPa on polyurethane with a hole in the fabric, and for radial movement of the shoulder surrounding the central hole in the polyurethane fabric of the lining element , in the surface of the rear disk of the impeller of the pump, a recess is provided in the form of an annular rectangular groove into which the shoulder enters. 2. The centrifugal pump according to claim 1, characterized in that in the central part of the polyurethane sheet linings of the body are integrated concentrically with a central hole in the sheet 2-4 compressed ring springs. 3. The centrifugal pump according to claim 1, characterized in that in the polyurethane fabric of the housing lining element, on its periphery, a ring made of rolled steel is concentrically concentric with ring springs (hereinafter referred to as a thrust ring). 4. The centrifugal pump according to claim 1, characterized in that 1-3 compressed ring springs integrated concentrically in the central part of the armored disk, developing a compression pressure of polyurethane of 0.5-5 MPa, and one steel thrust ring are embedded in the polyurethane fabric of the front armored disk, located on the periphery of the blade plate concentrically with ring springs. 5. The centrifugal pump according to claim 1, characterized in that in the polyurethane sheet of each of the impeller disks in its central part, concentrically with central holes in the disks, 1-3 compressed ring springs are developed, developing 0.5-5 MPa the compression pressure of the polyurethane, and one thrust ring located in the peripheral part of the canvas of each disk. 6. A centrifugal pump containing a coiled housing and cover, lined with structural elements made of polyurethane elastomer, a polyurethane impeller and a front armored disk, a steel drive shaft with a sealing system, shaft bearings, characterized in that it is integrated into the polyurethane fabric of the housing lining element from the drive side on the periphery of 1-4 annular tension springs in a stretched state (hereinafter unclamped annular springs), developing a compression pressure of polyurethane of 0.5-5 MPa. 7. The centrifugal pump according to claim 6, characterized in that in the central part of the polyurethane web of the housing lining element, on the drive side, a steel thrust ring is integrated concentrically with ring springs. 8. A centrifugal pump comprising a coiled housing and cover, lined inside with polyurethane elastomer elements, a polyurethane impeller, a steel drive shaft with a sealing system, shaft bearings, characterized in that the pump cover lining is embedded in a polyurethane fabric concentrically with a central hole in the fabric on the periphery of the open ring spring and in the central part - the thrust ring. 9. A centrifugal pump comprising a coiled housing and a lid internally lined with polymer elements, a polymer impeller, a steel drive shaft with a sealing system, shaft bearings, characterized in that the blades of the lining of the housing and the lid consist of bonded or thermally bonded welding of two layers of polymers having different linear thermal expansion coefficients in the range of 50-500%, while a layer, for example, of a polyurethane elastomer, facing the inside renney pump cavity has a smaller coefficient of linear thermal expansion than the adhered or welded thereto a layer of another elastomer or thermoplastic.

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