CN211900990U - Impeller for multistage centrifugal pump and multistage centrifugal pump - Google Patents

Abstract

An impeller for a multistage centrifugal pump and the multistage centrifugal pump belong to the technical field of centrifugal pumps. The impeller is of a split structure and comprises blades, an impeller rear cover plate, an impeller parent body and an impeller front cover plate, wherein the impeller parent body is of a disc structure formed by extending the periphery of a sleeve, the disc structure forms the impeller rear cover plate for installing the impeller, the side of the installed blade is an arc-shaped surface, 5 blades are evenly arranged between the arc-shaped surface and the impeller front cover plate at intervals along the circumference, the other side of the installed blade is a straight surface, and the end of the straight surface is of a sleeve structure. The utility model discloses reduce cavitation, the vibration phenomenon of machine pump, mechanical seal operates steadily to reach the efficiency that improves the pump, increase energy-conserving effect.

Description

Impeller for multistage centrifugal pump and multistage centrifugal pump

Technical Field

The utility model belongs to the technical field of the centrifugal pump, especially, relate to an impeller and multistage centrifugal pump for multistage centrifugal pump.

Background

In the existing multistage centrifugal pump, the opening of an impeller is 4mm, and the outer diameter of the impeller is 240 mm. The opening of the impeller is small and large in diameter, sand coating, sand holes and shrinkage porosity are easy to generate in the cast impeller, and integral casting cannot be performed. The steam is generated at the inlet of the impeller of the multistage centrifugal pump under certain vacuum pressure, the vaporized bubbles generate ablation on the metal surfaces of the impeller and the like under the impact motion of liquid particles, the whole process that the materials are damaged due to the formation, development and breakage of the steam bubbles is called a cavitation phenomenon, the material is damaged due to the generated cavitation, strong vibration can be caused, when the cavitation develops seriously, the cross section of a flow passage can be blocked due to the existence of a large number of steam bubbles, the energy obtained by the fluid from the impeller is reduced, the lift is reduced, the efficiency is correspondingly reduced, and the collapse of the steam bubbles causes vibration noise to influence the mechanical performance of the whole pump. Particularly, the first-stage impeller has more cavitation phenomena, particularly high-temperature and liquid hydrocarbon media, the cavitation can cause the material to be damaged, strong vibration can be caused, the mechanical performance of the whole pump can be influenced in serious cases, and even the operation of the whole device can be influenced.

SUMMERY OF THE UTILITY MODEL

To the technical problem that above-mentioned exists, in order to solve the cavitation that the first-stage impeller exists, the utility model provides an impeller and multistage centrifugal pump for multistage centrifugal pump through split type design, changes its overall structure, reduces the liquid stream and according to quickening with higher speed and reducing to reduce the cavitation.

The purpose of the utility model is realized through the following technical scheme:

the utility model relates to an impeller for multistage centrifugal pump, the impeller is split type structure, including blade, impeller back shroud, impeller parent, impeller front shroud, the impeller parent is extended into the disc structure in the sleeve periphery, the disc structure forms the impeller back shroud of installation impeller, and its installation blade side is the arcwall face, along 5 pieces of blades of the even interval arrangement of circumference between arcwall face and impeller front shroud, and the opposite side is straight face, and the straight face end is sleeve structure.

Preferably, the impeller front cover plate is of an arc structure, one end of the impeller front cover plate is provided with a sleeve connected with the impeller sealing ring, the other end of the impeller front cover plate is of a bell mouth shape, and the inner wall of the impeller front cover plate is of the same structure as the contact side of the blades; the bell mouth-shaped junction of the sleeve has a step to locate the impeller seal ring.

Preferably, the radian d of the front cover plate of the impeller in an arc structure is 80-85 degrees, and the curvature radius Ri is 19-19.8 mm.

Preferably, the blade is of an arc-shaped curved surface structure, the radian gamma is 90-100 degrees, and the curvature radius R is 192-195 mm.

Preferably, the diameter Di at the impeller inlet is 0.833Di in size, which is the diameter of the bass drum in the balancing mechanism.

A multistage centrifugal pump comprises a plurality of stages of impellers, the diameters of inlets of the two-stage impellers and the last-stage impellers of the impellers are the same, and the diameter d1 of the inlet of the first-stage impeller is larger than 3% -5% of the diameter d2 of the inlet of the two-stage impeller and the last-stage impeller.

Preferably, the curvature radius R1 at the inlet of the front cover plate of the first-stage impeller is 4-5% larger than that R2 at the inlet of the front cover plate of the second-stage to last-stage impellers.

The utility model has the advantages that:

1. the utility model discloses a set up multistage split type impeller, install along the even interval arrangement of circumference 5 pieces of blades on the impeller parent that has the disc structure, be used for installing stator and middle section respectively at the sleeve structure of impeller parent both sides, the runner that the medium passes through is satisfied in formation between stator, middle section and impeller, reduces cavitation, the vibration phenomenon of machine pump, and mechanical seal operates steadily to reach the efficiency that improves the pump, increase energy-conserving effect.

2. The utility model discloses an increase impeller entrance diameter, the curvature radius of increase impeller front shroud inducer to the entrance diameter of increase first-stage impeller and the curvature radius of impeller front shroud inducer, increased the flow area, reduce impeller import absolute speed and relative speed, thereby reduce the liquid stream urgent according to with higher speed and reduction, reduce the cavitation phenomenon, increased multistage centrifugal pump's life, make long-time steady operation of pump ability, brought huge economic benefits.

3. The utility model discloses when reducing the cavitation phenomenon and producing, reduce the medium to the erosion and abrasion of impeller, increase flow and lift, raise the efficiency, increase energy-conserving effect, reduce the vibration, the pump operation is stable.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic view of the installation structure of a single impeller.

Fig. 3 is a schematic view of the blade installation of fig. 1.

Fig. 4 is a side view of fig. 3.

Fig. 5 is a schematic structural view of a front cover plate of the impeller in fig. 1.

Fig. 6 is a schematic diagram of impeller parameters.

FIG. 7 is a prior art first stage impeller cavitation volume isosurface plot.

Fig. 8 is the isosurface map of the first-stage impeller cavitation volume of the present invention.

Fig. 9 is a schematic structural view of the present invention mounted on a centrifugal pump.

1. The impeller comprises an impeller, 101 blades, 102 an impeller rear cover plate, 103 an impeller parent body, 104 an impeller front cover plate, 105 an impeller sealing ring, 106 a middle section sealing ring, 107 a guide vane sealing ring and 108 a flow channel;

2. the first stage impeller, 3, the last stage impeller,

4. the cooling device comprises a driving end cooling box body, 5 parts of a front cover, 6 parts of a suction section, 7 parts of a non-driving end bearing component, 8 parts of a balance mechanism, 9 parts of a middle section, 10 parts of a discharge section, 11 parts of guide vanes, 12 parts of a penetrating rod nut, 13 parts of a rear cover, 14 parts of the non-driving end cooling box body, 15 parts of a pump shaft, 16 parts of a penetrating rod bolt, 17 parts of a driving end bearing component and 18 parts of a mechanical seal.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples.

Example (b): as shown in fig. 1, the utility model discloses a split type structure, including blade 101, impeller back shroud 102, impeller parent 103, impeller front shroud 104, impeller parent 103 extends into the disc structure in the sleeve periphery, the disc structure forms the impeller back shroud 102 of installation impeller, and its installation blade 101 side is the arcwall face, and the arcwall face end is through the impeller sealing ring 105 of putting on the impeller front shroud 104 and the middle section sealing ring 106 cooperation suit of impeller middle section inner circle, along the even interval arrangement of circumference 5 pieces of blade 101 between arcwall face and impeller front shroud 104, the opposite side is straight face, and straight face end is the sleeve structure, and when the installation, the sleeve of straight face end passes through stator sealing ring 17 installation stator 11.

As shown in fig. 5, the impeller front cover plate 104 is an arc-shaped structure, and the radian d is 80 to 85 degrees, in this example, d is 85 degrees; one end of the impeller is provided with a sleeve connected with the impeller sealing ring 105, the other end of the impeller is in a bell mouth shape, and the inner wall of the impeller front cover plate 104 is the same as the contact side structure of the blades, so that the impeller front cover plate and the blades are ensured to be in close contact; the bell-mouth connection of the sleeve is stepped to locate the impeller seal ring 105.

As shown in fig. 2, the middle section 9 of the impeller is an interstage diaphragm of each stage of impeller, and is used for being connected with an adjacent two-stage impeller structure in a matching manner, the connection part of two adjacent interstage diaphragms is a groove positioning matching structure, is connected with the impeller guide vanes on two adjacent sides through bolts, is sleeved with the impeller through a middle section sealing ring 106 in a matching manner, and is provided with an open groove opposite to the impeller and the guide vane end.

As shown in fig. 3 and 4, the vane 101 in this embodiment has an arc-shaped curved surface structure, the radian γ is 90 to 100 degrees, that is, γ is an included angle between an inner arc of the vane 71 relative to the middle section 9 and a horizontal axis of the pump shaft 15, and the curvature radius R is 192 to 195 mm; in this example γ is 100 degrees, R is 195mm, the diameter at the impeller inlet Di, Di size is 0.833Di, the Di size is the diameter of the bass drum in the balance mechanism, and Di in this example is 135 mm. The blades 101 are welded with the front cover plate 104 of the impeller, so that liquid is prevented from moving among the blades 101, the volume loss is reduced, and the efficiency of the pump is improved. The guide vane 11 is an open guide vane, that is, the opposite impeller end has an open slot, the open slots among the guide vane 11, the middle section 9 and the impeller form an integral flow channel 108, and the liquid flowing through the vane flows into the integral flow channel 108 through the vane and flows out through the flow channel between the middle section 9 and the guide vane 11. The open slot of open stator can increase the casting under the condition that satisfies the requirement, and the inside clearance of being convenient for is polished, reduces friction loss, improves the efficiency of pump.

As shown in fig. 2, the impeller sealing ring 105 is a sleeve structure that is engaged with the impeller front cover plate 104, the middle section sealing ring 106 is a cylindrical structure that is engaged with the impeller sealing ring 105 and the middle section 9 respectively and has a positioning step, and the guide vane sealing ring 107 is a cylindrical structure that is engaged with the impeller parent body 103 and the guide vane 11 and has a positioning step.

As shown in fig. 7 and 8, the cavitation bubble volume contour surface map of the first-stage impeller is the same as that of the first-stage impeller after optimization, cavitation erosion occurs before and after the first-stage impeller is optimized, the cavitation erosion area is mainly on the back side of the front edge of the blade as the hatching part shown in fig. 8, and the asymmetric distribution of cavitation bubbles can be clearly seen in the map, so that the cavitation flow has strong instability. Compared with the cavitation bubble form, the optimized impeller is smaller than the cavitation bubble form and the cavitation erosion area of the original impeller, and the cavitation erosion performance of the optimized impeller is obviously improved compared with the original impeller.

As shown in fig. 6 and 8, the utility model is used for a multistage centrifugal pump, including the suction section, spit out the section, pump shaft 15, impeller 1, mechanical seal 18, protecgulum 5, back lid 13, balance mechanism 11, drive end bearing part 2 and non-drive end bearing part 7, impeller 1 is multistage impeller, overlaps in order on pump shaft 15 between pump body suction section 6 and spit out section 10, the second grade of impeller to the last stage of impeller entrance diameter of impeller is the same, first stage impeller entrance diameter d1 is greater than the 3% -5% of second grade to last stage impeller entrance diameter d2, this example first stage impeller entrance diameter d1 is 110mm, second grade to last stage impeller entrance diameter d2 is 106.5mm, has increased the flow area, reduces the cavitation scene and produces; every impeller 1 corresponds pump body suction section 6 and middle section 9, it sets up stator 11 to correspond spitting section 10, pump body suction section 6 sets up on pump shaft 15, pump body spitting section 10 is put on pump shaft 15 and last stage impeller sleeve through balance mechanism 11 cover, form the pump chamber of medium flow between pump body suction section 6 and spitting section 10, pump body suction section 6 connects protecgulum 5, connect drive end cooling body 4 one end through protecgulum 5, the drive end cooling body 4 other end connects drive end bearing part 17, spit section 10 end connection back lid 13, connect non-drive end cooling body 14 one end through back lid 13, non-drive end cooling body 14 other end connects non-drive end bearing part 7, all be provided with the mechanical seal 18 of cover on the pump shaft in the recess of drive end cooling body 4 and non-drive end cooling body 14.

The curvature radius R1 at the inlet of the front cover plate of the first-stage impeller is 4-5% larger than that R2 at the inlet of the front cover plate of the second-stage to last-stage impellers; in the embodiment, the curvature radius R1 at the inlet of the front cover plate of the first-stage impeller is 19.8mm, and the curvature radius R2 at the inlet of the front cover plate of the second-stage to last-stage impellers is 19 mm; the cavitation phenomenon is reduced while the mechanical performance is not influenced.

Other parts not mentioned in this example are all the existing general structures well known to those skilled in the art.

It should be understood that the above detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as the use requirement is satisfied, the utility model is within the protection scope.

Claims (7)

1. An impeller for a multistage centrifugal pump, characterized by: the impeller is of a split structure and comprises blades, an impeller rear cover plate, an impeller parent body and an impeller front cover plate, wherein the impeller parent body is of a disc structure formed by extending the periphery of a sleeve, the disc structure forms the impeller rear cover plate for installing the impeller, the side of the installed blade is an arc-shaped surface, 5 blades are evenly arranged between the arc-shaped surface and the impeller front cover plate at intervals along the circumference, the other side of the installed blade is a straight surface, and the end of the straight surface is of a sleeve structure.

2. The impeller for a multistage centrifugal pump according to claim 1, wherein: the impeller front cover plate is of an arc-shaped structure, one end of the impeller front cover plate is provided with a sleeve connected with the impeller sealing ring, the other end of the impeller front cover plate is of a bell mouth shape, and the inner wall of the impeller front cover plate is of the same structure as the contact side of the blades; the bell mouth-shaped junction of the sleeve has a step to locate the impeller seal ring.

3. The impeller for a multistage centrifugal pump according to claim 2, wherein: the radian alpha of the impeller front cover plate in an arc-shaped structure is 80-85 degrees, and the curvature radius Ri is 19-19.8 mm.

4. The impeller for a multistage centrifugal pump according to claim 1, wherein: the blade is of an arc-shaped curved surface structure, the radian gamma is 90-100 degrees, and the curvature radius R is 192-195 mm.

5. The impeller for a multistage centrifugal pump according to claim 1, wherein: the diameter Di at the inlet of the impeller is 0.833Di, and the size Di is the diameter of the big drum in the balance mechanism.

6. A multistage centrifugal pump characterized by: an impeller according to any one of claims 1 to 4 comprising a plurality of stages, the impellers having the same diameter at the inlet of the second to last stage impellers, the diameter at the inlet of the first stage impeller d1 being between 3% and 5% greater than the diameter d2 at the inlet of the second to last stage impeller.

7. The multistage centrifugal pump of claim 6, wherein: the curvature radius R1 at the inlet of the front cover plate of the first-stage impeller is 4-5% larger than that R2 at the inlet of the front cover plate of the second-stage to last-stage impellers.

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