CN212003608U

CN212003608U - Small-flow high-lift multistage centrifugal pump

Info

Publication number: CN212003608U
Application number: CN202020513905.XU
Authority: CN
Inventors: 蔡振宇; 袁永胜; 张新
Original assignee: Shenyang Huake Pump Manufacturing Co ltd
Current assignee: Shenyang Huake Pump Manufacturing Co ltd
Priority date: 2020-04-09
Filing date: 2020-04-09
Publication date: 2020-11-24
Anticipated expiration: 2030-04-09

Abstract

A small-flow high-lift multistage centrifugal pump belongs to the technical field of centrifugal pumps. Including the pump body, pump shaft, impeller, mechanical seal, protecgulum, back lid, mechanical seal, balance mechanism, drive end bearing unit and non-drive end bearing unit, the impeller is multistage impeller, overlaps in order and puts on the pump shaft between the pump body suction segment and the section of spitting out, every the impeller corresponds the pump body suction segment and middle section, corresponds the section of spitting out and sets up the impeller stator, and suction segment overlaps and puts on the pump shaft, and the section of spitting out is put on pump shaft and last stage impeller sleeve through the balance mechanism cover, and suction segment connects the protecgulum, through drive end cooling letter body coupling drive end bearing unit, spits out the section end and connects the back lid, through non-drive end cooling letter body coupling non-drive end bearing unit, all be provided with the cover in the epaxial mechanical seal of pump in the recess of drive end cooling letter body and non-drive end cooling letter body. The utility model discloses can reduce the cavitation, the vibration phenomenon of machine pump, improve the efficiency of pump.

Description

Small-flow high-lift multistage centrifugal pump

Technical Field

The utility model belongs to the technical field of the centrifugal pump, especially, relate to a low discharge high-lift multistage centrifugal pump.

Background

At present, the small-flow high-lift multistage centrifugal pump is a multistage centrifugal pump with the specific pump speed ns less than 45. The majority adopts a high-speed tangent pump, the rotating speed of the pump is about 20000r/min, and the stability is extremely poor due to too high rotating speed. And the plunger type reciprocating pump has short service life, high maintenance frequency and high maintenance cost. The specific rotation speed of the pump is a similar judgment number of the pump, ns is 3.65n multiplied by Q0.5/Hi 0.75, wherein n is the rotation speed r/min of the pump, Q is the flow m 3/s of the pump, and Hi is the single-stage head of the pump. The pump balance mechanism is a balance mechanism with a single balance drum or a single balance disc, after the pump balance mechanism runs for a long time, parts are abraded, the balance performance is reduced due to the fact that the fit clearance is increased, the axial force of a rotor is unstable, the amount of movement is large, the impact force on a mechanical seal is large, the mechanical seal is easy to damage, the oil cavity of the pump bearing body is small due to the structure of the pump bearing body, the oil storage amount is small, the impact load bearing capacity of a rolling bearing is poor, the sound is large when the pump runs at a high speed, when the pump runs for a long time, the axial force borne by a thrust bearing is too large, the bearing is damaged due to fatigue. In the existing water injection pump for the hydrogenation device, the flow rate Q is 8m3/h, the head 820m, the rotating speed 2980r/min of the pump, the stage number of the pump is 10, the specific rotating speed ns of the pump is 19, and the opening inner diameter of the impeller is 4mm, and the outer diameter of the impeller is 240 mm. The opening of the impeller is small and large in diameter, and sand coating, sand holes and shrinkage porosity are easily generated in the cast impeller, so that integral casting cannot be realized. The pump shaft of the pump is thin, has weak bearing force, extremely poor integral stability and large vibration, and the bearing and the mechanical seal are easy to damage.

SUMMERY OF THE UTILITY MODEL

To the technical problem that above-mentioned exists, this is novel to provide a small discharge high-lift multistage centrifugal pump, reduces the cavitation, the vibration phenomenon of pump, and the operation is stable.

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

the utility model relates to a small-flow high-lift multistage centrifugal pump, which comprises a suction section, a discharge section, a pump shaft, an impeller, a mechanical seal, a front cover, a rear cover, a mechanical seal, a balance mechanism, a drive end bearing part and a non-drive end bearing part, wherein the impeller is a multistage impeller which is sequentially sleeved on a pump shaft between the suction section and the discharge section, each impeller corresponds to the suction section and a middle section, an impeller guide vane is arranged corresponding to the discharge section, the suction section is sleeved on the pump shaft, the discharge section is sleeved on the pump shaft and a final-stage impeller sleeve through the balance mechanism, a pump cavity with medium flowing is formed between the suction section and the discharge section, the suction section is connected with the front cover, the front cover is connected with one end of a drive end cooling box body, the other end of the drive end cooling box body is connected with the drive end bearing part, the end of the discharge section is connected with the rear cover, one end of the non-drive end cooling box body is connected with the non-drive end, and mechanical seals sleeved on the pump shaft are arranged in the grooves of the driving end cooling box body and the non-driving end cooling box body.

Preferably, 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, its installation blade side of the impeller back shroud that the disc structure formed the installation impeller is the arcwall face, and the cambered surface end passes through the impeller sealing ring that the impeller front shroud upper cover put and the middle section sealing ring cooperation suit of impeller middle section inner circle, arranges 5 pieces of blades along the even interval of circumference between arcwall face and impeller front shroud, and the opposite side is straight face, and the sleeve of straight face end passes through stator sealing ring installation stator.

Preferably, the impeller front cover plate is of an arc structure, the radian alpha of the impeller front cover plate is 80-85 degrees, 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 in a bell mouth shape, and the inner wall of the impeller front cover plate is identical to the contact side structure of the blade; the bell mouth-shaped connection part of the sleeve is provided with a step to position the impeller sealing ring; 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 non-driving end bearing part comprises a non-driving end bearing body, a bearing, a shaft sleeve, an oil ring sleeve, an anti-rotation sleeve, a bearing body upper cover, an upper bearing bush, a lower bearing bush, an oil slinger, a non-driving end bearing cover and a labyrinth ring, the upper end of the non-driving end bearing body is connected with the bearing body upper cover to form an integral sleeve which is sleeved at one end of the pump shaft, the non-driving end bearing body and the bearing body upper cover at the end part of the pump shaft are connected with a non-driving end bearing press cover, two communicated lubricating oil cavities are arranged between the non-driving end bearing body and the bearing body upper cover, the bearing is arranged on the small-diameter pump shaft section through the shaft sleeve, the bearing outer ring is sleeved with the anti-rotation sleeve, two ends of the anti-rotation sleeve are respectively connected with the non-driving end bearing press cover and the non-driving end bearing body, the oil ring sleeve is further, The lower bearing bush is assembled on the large-diameter pump shaft section, a non-drive end oil slinger is arranged on the lower bearing bush, the other ends of the non-drive end bearing body and the bearing body upper cover are sleeved on the pump shaft through a labyrinth ring, a non-drive end water-cooling cavity is further arranged below an oil cavity of the non-drive end bearing body and is located on the periphery of a non-drive end lubricating oil cavity, a cooling water pipeline connector is connected to the non-drive end water-cooling cavity, and a lubricating oil pipeline connector is connected to the non-drive end lubricating oil cavity.

Preferably, the non-driving end bearing body is internally provided with a supporting seat for supporting the lower bearing bush and a first mounting seat for mounting the bearing; a second mounting seat for mounting a bearing is arranged in the upper cover of the bearing body, and lubricating oil injection holes are formed in the upper cover of the bearing body corresponding to the two lubricating oil cavities; a lubricating oil outlet is formed in the side wall of the bearing body at the non-driving end; the water cooling cavity is provided with a water cooling cavity cover, and a cooling water inlet and a cooling water outlet are arranged on the water cooling cavity cover.

Preferably, the driving end bearing part comprises a driving end bearing body, a driving end bearing body upper cover, an upper bearing bush, a lower bearing bush, a driving end oil slinger and a labyrinth ring, wherein the labyrinth ring sleeved on the pump shaft is connected to two ends of the driving end bearing body upper cover respectively; and a drive end water cooling cavity is also arranged below the drive end oil cavity of the drive end bearing body, and a water inlet and a water outlet are connected to the drive end water cooling cavity.

Preferably, the front cover is a structure which is arranged on the periphery of an arc-shaped body part with a hole in the middle part and is respectively connected and matched with the suction section of the pump body and the driving end cooling box body, the arc-shaped body part is sleeved at one end of the driving end cooling box body through the hole in the middle part, and an arc-shaped groove is formed in the connecting side of the arc-shaped body part and the driving end cooling box body; the connection end of the drive end cooling box body and the front cover is provided with a step opening groove which is connected with the arc groove in a matched mode, the step opening groove is communicated with the arc groove to form a cooling cavity, and a water inlet and a water outlet which are communicated with the cooling cavity are formed in the drive end cooling box body.

Preferably, the balance mechanism comprises an inner ring, an outer ring and a positioning structure, the inner ring comprises a balance disc and a balance disc adjusting ring, the balance disc is sleeved on the pump shaft, the balance disc adjusting ring is arranged between one end of the balance disc, which is in contact with the positioning structure, and the pump shaft, and the other end of the balance disc is sleeved with the final-stage impeller end in a matching manner; the outer ring comprises a balance sleeve and a balance sleeve pressing plate, the balance sleeve is sleeved on the periphery of the sleeving end of the balance disc and the final-stage impeller, the balance sleeve pressing plate is sleeved on the periphery of the contact end of the positioning structure, and the discharge section is connected through the balance sleeve and the balance sleeve pressing plate.

Preferably, the cross section of the balance disc is a T-shaped sleeve structure, an annular groove matched with the final-stage impeller is formed on the inner wall of the small-diameter end part, a clearance groove of a key groove is further formed on the inner wall, a groove matched with the mounting end of the balance sleeve is formed on the side where the large diameter is connected with the small diameter, a groove formed on the end surface contacted with the balance sleeve forms a clearance, and the relation between the radial length L1 of the clearance and the length L2 of the contact surface between the balance disc and the balance sleeve is as follows: l1 is 80% to 82% of L2.

Preferably, the positioning structure comprises a positioning groove, a positioning ring and a positioning sleeve, the positioning groove is formed in the pump shaft close to the non-driving end cover, the positioning ring matched with the positioning groove is arranged on the pump shaft and is in contact with one end of the balance disc adjusting ring, the positioning sleeve is sleeved on the periphery of the positioning ring, and the positioning sleeve is connected with the balance disc through the positioning sleeve.

The utility model has the advantages that:

1. the utility model discloses a set up multistage split type impeller to set up balance mechanism at non-drive end, parts machining, installation, dismantlement, easy maintenance reduce cavitation, the vibration phenomenon of machine pump, mechanical seal operates steadily, thereby reaches the efficiency that improves the pump, increases energy-conserving effect. The small-flow high-lift multi-stage pump is easy to manufacture, the stage number of the pump can be determined according to the flow lift, the pump requirement of the small-flow high-lift pump in the petroleum and petrochemical market is well met, and good economic benefits and social benefits are brought to manufacturing enterprises and using units.

2. The utility model discloses a drive end bearing body is slide bearing, has reliable operation, steady noiseless, and the lubricating oil reservoir has the shock-absorbing capacity, so can bear characteristics such as great impact load, is equipped with the water cooling chamber below the oil pocket. The non-drive end bearing body is a mode of combining the sliding bearing with the thrust bearing, the mode can ensure the positioning of the rotor, and the thrust bearing effectively bears the residual axial force from the sliding bearing.

3. The balance mechanism of the utility model positions the balance disc rotating along with the pump shaft through the positioning structure, connects the pump body through the balance sleeve and the balance pressing plate, and sets the thrust bearing in the bearing part of the non-driving end, ensures that the gap between the balance disc and the balance sleeve is 0.08 mm-0.102 mm, can ensure that the pump does not damage the balance mechanism when running, can still balance 90-95% of axial force after the balance disc and the balance sleeve are worn, the residual axial force is born by the thrust bearing, and can greatly reduce the load of the thrust bearing; during operation, if the thrust bearing is damaged, the balance mechanism can still keep the rotor balanced without damaging other parts.

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. 2.

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. 2.

Fig. 6 is a schematic structural diagram of the non-driving-end bearing body in fig. 1.

Fig. 7 is a schematic structural view of a bearing body of the driving end in fig. 1.

Figure 8 is a schematic view of the coupling structure between the cooling nut at the driving end and the front cover in figure 1.

Fig. 9 is a schematic structural view of the balancing mechanism in fig. 1.

1. The bearing comprises a non-driving end bearing component, 101, a non-driving end bearing cover, 102, an oil ring sleeve, 103, a bearing, 104, an anti-rotation sleeve, 105, a shaft sleeve, 106, an oil chamber, 107, a bearing body upper cover, 108, an upper bearing bush, 109, an oil slinger, 110, a labyrinth ring, 111, a bearing body, 112, a water cooling chamber cover, 113, a lower bearing bush, 114, a water cooling chamber, 115, a first mounting seat and 116, and a second mounting seat;

2. a drive end bearing member for supporting the drive end,

3. mechanical seal, 4. drive end cooling box, 41. open groove, 42. cooling cavity, 5. front cover, 51. arc body part, 52. arc groove, 6. suction section,

7. the impeller comprises an impeller, 71 blades, 72 an impeller rear cover plate, 73 an impeller parent body, 74 an impeller front cover plate, 75 an impeller sealing ring, 76 a middle section sealing ring, 77 a guide vane sealing ring and 78 a flow channel;

8. balance mechanism, 81 balance disc, 811 gap, 812 recess groove, 813 annular groove, 82 balance sleeve, 821 seal groove, 83 balance sleeve pressure plate, 84 positioning ring, 85 positioning sleeve, 86 balance disc adjusting ring;

9. middle section, 10, spit section, 11, guide vane, 12, through-bar nut, 13, rear cover, 14, non-drive end cooling box body, 15, pump shaft, 16, through-bar bolt.

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 present invention relates to a small-flow high-lift multistage centrifugal pump, which comprises a suction section, a discharge section, a pump shaft 15, impellers 7, a mechanical seal 3, a front cover 5, a rear cover 13, a balance mechanism 11, a drive end bearing part 2 and a non-drive end bearing part 1, wherein the impellers 7 are multistage impellers, and are sequentially sleeved on the pump shaft 15 between a pump body suction section 6 and a discharge section 10, each impeller 7 corresponds to a pump body suction section 6 and a middle section 9, a guide vane 11 is arranged corresponding to the discharge section 10, the pump body suction section 6 is sleeved on the pump shaft 15, the pump body discharge section 10 is sleeved on the pump shaft 15 and an impeller sleeve through the balance mechanism 11, a medium flowing pump cavity is formed between the pump body suction section 6 and the discharge section 10, the pump body suction section 6 is connected with the front cover 5, one end of a drive end cooling box 4 is connected through the front cover 5, the other end of the cooling box 4 is connected with the drive end bearing part 2, the end of the spitting section 10 is connected with a rear cover 13, one end of a non-driving end cooling box body 14 is connected with the rear cover 13, the other end of the non-driving end cooling box body 14 is connected with a non-driving end bearing part 1, and mechanical seals 3 sleeved on the pump shaft are arranged in grooves of the driving end cooling box body 4 and the non-driving end cooling box body 14.

As shown in fig. 2-5, the impeller is a split structure, including blade 71, impeller back shroud 72, impeller parent 73, impeller front shroud 74, impeller parent 73 is the disc structure that extends into in the sleeve periphery, its installation blade 71 side of the impeller back shroud 72 that the disc structure formed the installation impeller is the arcwall face, and the cambered surface end is through the impeller sealing ring 75 that the cover was put on impeller front shroud 74 and the cooperation suit of middle section sealing ring 76 of impeller middle section inner circle, arranges 5 pieces of blades 71 along the even interval of circumference between arcwall face and impeller front shroud 74, and the opposite side is the straight face, and the sleeve of straight face end passes through stator sealing ring 77 installation stator 11.

As shown in fig. 5, the impeller front cover plate 74 is an arc-shaped structure, the radian α of the impeller front cover plate is 80-85 degrees, in this example, α is 85 degrees, one end of the impeller front cover plate is provided with a sleeve connected with the impeller sealing ring 75, the other end of the impeller front cover plate is in a bell mouth shape, and the inner wall of the impeller front cover plate 74 and the contact side of the blade have the same structure, so that the impeller front cover plate and the blade are; the bell-mouth connection of the sleeve is stepped to locate the impeller seal ring 75.

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 the adjacent two stages of impeller structures in a matching manner, the connection part of the 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 76 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 71 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 and R is 195 mm. The vanes 71 are welded with the front cover plate 74 of the impeller, so that liquid is prevented from moving among the vanes 71, 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 78, and the liquid flowing through the vane flows into the integral flow channel 78 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 seal ring 75 is a sleeve structure that is engaged with the impeller front cover plate 74, the middle section seal ring 76 is a cylindrical structure that is engaged with the impeller seal ring 75 and the middle section 9 respectively and has a positioning step, and the guide vane seal ring 77 is a cylindrical structure that is engaged with the impeller parent 73 and the guide vane 11 and has a positioning step.

As shown in fig. 6, the non-driving end bearing component 1 includes a non-driving end bearing body 111, a bearing 103, a shaft sleeve 105, an oil ring sleeve 102, an anti-rotation sleeve 104, a bearing body upper cover 107, an upper bearing bush 108, a lower bearing bush 113, an oil slinger, a non-driving end bearing cover 101 and a labyrinth ring 110, the upper end of the non-driving end bearing body 111 is connected with the bearing body upper cover 107 to form an integral body which is sleeved at one end of the pump shaft 15, the non-driving end bearing body 111 and the bearing body upper cover 107 at the end of the pump shaft 15 are connected with the non-driving end bearing cover 101, two communicated lubricating oil cavities 106 are arranged between the non-driving end bearing body 111 and the bearing body upper cover 107, the bearing 103 is installed on a small-diameter pump shaft section through the shaft sleeve 105, the outer ring of the bearing 103 is sleeved on the shaft sleeve 104, two ends of the anti-rotation sleeve 104 are respectively connected to the non-driving end bearing cover 101 and the non-, the oil-free lubricating device is characterized in that an oil slinger is arranged on the oil slinger, an upper bearing bush 108 and a lower bearing bush 113 are combined and installed on a large-diameter pump shaft section, a non-driving-end oil slinger 109 is arranged on the oil slinger, the other ends of a non-driving-end bearing body 111 and a bearing body upper cover 107 are sleeved on a pump shaft 15 through a labyrinth ring 110, a non-driving-end water-cooling cavity 114 is further arranged below an oil cavity 106 of the non-driving-end bearing body 111 and is located on the periphery of the non-driving-end lubricating oil cavity 106, a cooling water pipeline joint is connected to the non.

The bearing 103 is two thrust bearings, and is arranged between the shaft sleeve 105 and the anti-rotation sleeve 104 in parallel. The mounting mode can ensure the positioning of the rotor, and the thrust bearing effectively bears the residual axial force from the balance mechanism.

The bearing body 111 at the non-driving end is internally provided with a supporting seat for supporting a lower bearing bush 113 and a first mounting seat 115 for mounting the bearing 103; a second mounting seat 116 for mounting a bearing is arranged in the bearing body upper cover 107, and lubricating oil injection holes are formed in the bearing body upper cover 107 corresponding to the two non-driving-end lubricating oil cavities; and a lubricating oil outlet is formed in the side wall of the non-driving-end bearing body 111.

The water cooling cavity is provided with a water cooling cavity cover 112, and a cooling water inlet and a cooling water outlet are arranged on the water cooling cavity. The labyrinth ring 110 is of a split structure and comprises an upper part and a lower part, the installed whole is circular, the outer ring of the upper part is in fit connection with the upper cover 107 of the bearing body, the outer ring of the lower part is in fit connection with the non-drive end bearing body 111, and the inner rings of the upper part and the lower part are buckled on the pump shaft 15; and 2-3 sealing grooves are formed in the inner ring and used for sealing lubricating oil.

As shown in fig. 7, the drive end bearing member 2 includes a drive end bearing body 202, a drive end bearing body upper cover 207, an upper bearing bush 208, a lower bearing bush 205, a drive end oil slinger 209, and a labyrinth ring, two ends of the driving end bearing body upper cover 207 are respectively connected with a labyrinth ring 204 sleeved on the pump shaft, the driving end bearing body 202 is installed in a matching way with the labyrinth ring 204 and is connected with the driving end bearing body upper cover 207, an upper bearing bush 208 and a lower bearing bush 205 which are buckled and connected are respectively arranged on the pump shaft between the driving end bearing body 202 and the driving end bearing body upper cover 207, the lower bearing shell 205 is placed on a support 210 in the drive end bearing body 202, a drive end oil chamber 203 is formed on both sides of the support 210, two driving end oil slingers 209 are symmetrically arranged between an upper bearing bush 208 and a lower bearing bush 205 corresponding to the positions of the two communicated driving end oil cavities 203, an oil inlet is formed in an upper cover 207 of a driving end bearing body, and an oil outlet communicated with the driving end oil cavities 203 is formed in the wall of the driving end bearing body 202; a driving end water-cooling cavity 201 is further arranged below the driving end oil cavity 203 of the driving end bearing body, and a water inlet and a water outlet are connected to the driving end water-cooling cavity.

The drive end bearing body 202 described in this example has the characteristics of reliable operation, stability, no noise, vibration absorption capability of the lubricating oil layer, capability of bearing larger impact load and the like.

As shown in fig. 8, the pump body front cover 5 is a structure that the periphery of an arc body part 51 with a hole in the middle is provided with a structure that is respectively connected and matched with the pump body suction section 6 and the driving end cooling letter 4, the arc body part 51 is sleeved at one end of the driving end cooling letter 4 through the hole in the middle, and an arc groove 52 is formed at the connecting side of the arc body part and the driving end cooling letter 4; the connection end of the driving end cooling box body 4 and the front cover 5 is provided with a step opening groove 41 which is matched and connected with the arc-shaped groove 52, the step opening groove 41 is communicated with the arc-shaped groove 52 to form a cooling cavity 42, and the driving end cooling box body 4 is provided with a water inlet and a water outlet which are communicated with the cooling cavity 42.

As shown in fig. 1, the rear cover 13 is used to connect the non-drive cooling half 14 to the pump body, the non-drive cooling half 14 has a recess, and a cooling cavity is formed between the rear cover 13 and the recess. Is of conventional structure.

As shown in fig. 9, the balance mechanism in this example is a double-balance drum balance mechanism, which includes an inner ring, an outer ring, and a positioning structure, where the inner ring includes a balance disk 81 and a balance disk adjusting ring 86, the balance disk 81 is sleeved on the pump shaft 15, the balance disk adjusting ring 86 is disposed between one end of the balance disk 81, which is in contact with the positioning structure, and the pump shaft 15, and the other end of the balance disk 81 is sleeved with the last-stage impeller end in a matching manner; the outer ring comprises a balance sleeve 82 and a balance sleeve pressing plate 83, the balance sleeve 82 is sleeved on the periphery of the sleeving end of the balance disc 81 and the final-stage impeller, the balance sleeve pressing plate 83 is sleeved on the periphery of the end, contacted with the positioning structure, of the balance sleeve, and the balance sleeve pressing plate 82 and the balance sleeve pressing plate 83 are connected with the pump body.

The balance disc 81 is of a T-shaped sleeve structure in section, an annular groove 813 matched with a final-stage impeller is formed in the inner wall of the small-diameter end portion, a blank groove 812 of a key groove is further formed in the inner wall of the small-diameter end portion, the balance disc 81 is fixedly connected with the pump shaft 15 through a key, a groove matched with the mounting end of the balance sleeve 82 is formed in the side, where the large diameter is connected with the small diameter, of the balance disc, an opening groove formed in the end face, in contact with the balance sleeve 82, of the groove forms a gap 811, and the relationship among the radial length L1 of the gap 811, the contact surface length L2 between the balance disc 81 and the balance sleeve: l1 is 80% -82% of L2; the radial length of the interspace 811 determines the size of the contact surface between the balancing disk 81 and the balancing sleeve 82, and thus the effect of the balancing force; the axial length of the void 811 functions to: when the liquid passes through the gap between the balance disk 81 and the balance sleeve 82, the liquid flows to the gap 811 to play a role of buffering.

The balance sleeve 82 is of a T-shaped sleeve structure matched with the balance disc, an open groove matched with the groove in the balance disc 81 is formed in the large-diameter end face of the balance sleeve, which is in contact with the balance disc 81, a gap 811 is formed between the groove and the open groove, and two seal grooves 81 for mounting seal rings are formed in the outer wall of the small diameter.

The balance sleeve pressure plate 83 is of a lantern ring structure, the inner diameter of the balance sleeve pressure plate is matched with the large-diameter end of the balance disc 81, and the periphery of the balance sleeve pressure plate is matched with the balance sleeve 82 and the opposite installation end of the spitting section 10.

The positioning structure comprises a positioning groove, a positioning ring 84 and a positioning sleeve 85, the positioning groove is formed in the pump shaft 15 close to the rear cover 13 of the non-driving end, the positioning ring 84 matched with the positioning groove is arranged on the positioning groove and is in contact with one end of a balance disc adjusting ring 86, the positioning sleeve 85 is sleeved on the periphery of the positioning ring 84, and the positioning sleeve 85 and the balance disc 81 are connected through bolts.

The bearing 103 in the non-driving end bearing part 1 is a thrust bearing, and the axial clearance between the balance disc 81 and the balance sleeve 82 is ensured to be 0.1-0.012 mm; the clearance dimension set in this example ensures a small amount of liquid leakage through the balance disk 81 and also makes it difficult to wear the balance disk 81.

By arranging the balance mechanism of the utility model, the balance mechanism can be ensured not to be damaged when the pump runs, 90-95% of axial force can still be balanced after the balance disc 81 and the balance sleeve 82 are worn, and the residual axial force is borne by the thrust bearing, so that the load of the thrust bearing 103 can be greatly reduced; during operation, if the thrust bearing 103 is damaged, the balance mechanism can still keep the rotor balanced without grinding other parts.

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

1. The utility model provides a multistage centrifugal pump of low discharge high lift, includes suction section, spits section, pump shaft, impeller, mechanical seal, protecgulum, back lid, balance mechanism, drive end bearing unit and non-drive end bearing unit, its characterized in that: the impeller is a multistage impeller, and is sleeved on a pump shaft between a suction section and a discharge section in sequence, each impeller corresponds to a suction section and a middle section, an impeller guide vane is arranged corresponding to the discharge section, the suction section is sleeved on the pump shaft, the discharge section is sleeved on the pump shaft and a final-stage impeller sleeve through a balance mechanism, a medium flowing pump cavity is formed between the suction section and the discharge section, the suction section is connected with a front cover, one end of a driving-end cooling box body is connected through the front cover, the other end of the driving-end cooling box body is connected with a driving-end bearing part, the end of the discharge section is connected with a rear cover, one end of a non-driving-end cooling box body is connected through the rear cover, the other end of the non-driving-end cooling box body is connected with a non-driving-end bearing part, and mechanical seals sleeved on the pump shaft are arranged.

2. The low-flow high-lift multistage centrifugal pump of claim 1, characterized in that: the impeller is split type structure, including blade, impeller back shroud, impeller parent, impeller front shroud, the impeller parent extends into the disc structure in the sleeve periphery, its installation blade side of the impeller back shroud that the disc structure formed installation impeller is the arcwall face, and the cambered surface end passes through the impeller sealing ring that the impeller front shroud upper cover put and the middle section sealing ring cooperation suit of impeller middle section inner circle, along the even interval arrangement of circumference 5 pieces of blades between arcwall face and impeller front shroud, and the opposite side is straight face, and the sleeve of straight face end passes through stator sealing ring installation stator.

3. The low-flow high-lift multistage centrifugal pump of claim 2, characterized in that: the impeller front cover plate is of an arc structure, the radian alpha of the impeller front cover plate is 80-85 degrees, one end of the impeller front cover plate is provided with a sleeve connected with an impeller sealing ring, the other end of the impeller front cover plate is of a horn mouth shape, and the inner wall of the impeller front cover plate is identical to the contact side structure of the blade; the bell mouth-shaped connection part of the sleeve is provided with a step to position the impeller sealing ring; 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.

4. The low-flow high-lift multistage centrifugal pump of claim 1, characterized in that: the non-driving end bearing part comprises a non-driving end bearing body, a bearing, a shaft sleeve, an oil ring sleeve, an anti-rotation sleeve, a bearing body upper cover, an upper bearing bush, a lower bearing bush, an oil slinger, a non-driving end bearing cover and a labyrinth ring, wherein the upper end of the non-driving end bearing body is connected with the bearing body upper cover to form an integral sleeve which is sleeved at one end of the pump shaft, the non-driving end bearing body and the bearing body upper cover at the end part of the pump shaft are connected with a non-driving end bearing press cover, two communicated lubricating oil cavities are arranged between the non-driving end bearing body and the bearing body upper cover, the bearing is arranged on a small-diameter pump shaft section through the shaft sleeve, the anti-rotation sleeve is sleeved on a bearing outer ring, two ends of the anti-rotation sleeve are respectively connected with the non-driving end bearing cover and the non-driving end bearing body, the oil ring sleeve is further sleeved on the pump shaft between the end part, the oil cavity of the non-driving end bearing body is provided with a non-driving end water-cooling cavity which is positioned at the periphery of the non-driving end lubricating oil cavity, the non-driving end water-cooling cavity is connected with a cooling water pipeline connector, and the non-driving end lubricating oil cavity is connected with a lubricating oil pipeline connector.

5. The low-flow high-lift multistage centrifugal pump of claim 4, characterized in that: the non-driving end bearing body is internally provided with a supporting seat for supporting a lower bearing bush and a first mounting seat for mounting a bearing; a second mounting seat for mounting a bearing is arranged in the upper cover of the bearing body, and lubricating oil injection holes are formed in the upper cover of the bearing body corresponding to the two lubricating oil cavities; a lubricating oil outlet is formed in the side wall of the bearing body at the non-driving end; the water cooling cavity is provided with a water cooling cavity cover, and a cooling water inlet and a cooling water outlet are arranged on the water cooling cavity cover.

6. The low-flow high-lift multistage centrifugal pump of claim 1, characterized in that: the driving end bearing part comprises a driving end bearing body, a driving end bearing body upper cover, an upper bearing bush, a lower bearing bush, a driving end oil slinger and a labyrinth ring, wherein the labyrinth ring sleeved on the pump shaft is connected to two ends of the driving end bearing body upper cover respectively; and a drive end water cooling cavity is also arranged below the drive end oil cavity of the drive end bearing body, and a water inlet and a water outlet are connected to the drive end water cooling cavity.

7. The low-flow high-lift multistage centrifugal pump of claim 6, characterized in that: the front cover is a structure which is arranged on the periphery of an arc-shaped body part with a hole in the middle part and is respectively connected and matched with the suction section of the pump body and the driving end cooling box body, the arc-shaped body part is sleeved at one end of the driving end cooling box body through the hole in the middle part, and an arc-shaped groove is formed at the connecting side of the arc-shaped body part and the driving end cooling box body; the connection end of the drive end cooling box body and the front cover is provided with a step opening groove which is connected with the arc groove in a matched mode, the step opening groove is communicated with the arc groove to form a cooling cavity, and a water inlet and a water outlet which are communicated with the cooling cavity are formed in the drive end cooling box body.

8. The low-flow high-lift multistage centrifugal pump of claim 1, characterized in that: the balance mechanism comprises an inner ring, an outer ring and a positioning structure, the inner ring comprises a balance disc and a balance disc adjusting ring, the balance disc is sleeved on the pump shaft, the balance disc adjusting ring is arranged between one end of the balance disc, which is in contact with the positioning structure, and the pump shaft, and the other end of the balance disc is sleeved with the last-stage impeller end in a matched manner; the outer ring comprises a balance sleeve and a balance sleeve pressing plate, the balance sleeve is sleeved on the periphery of the sleeving end of the balance disc and the final-stage impeller, the balance sleeve pressing plate is sleeved on the periphery of the contact end of the positioning structure, and the discharge section is connected through the balance sleeve and the balance sleeve pressing plate.

9. The low-flow high-lift multistage centrifugal pump of claim 8, wherein: the section of the balance disc is of a T-shaped sleeve structure, an annular groove which is matched and installed with a final-stage impeller is formed in the inner wall of the end part with the small diameter, a clearance groove of a key groove is further formed in the inner wall of the end part with the small diameter, a groove which is matched with the installation end of the balance sleeve is formed in the connecting side of the large diameter and the small diameter, a groove which is formed in the end face, which is contacted with the balance sleeve, of the clearance groove forms a clearance, and the relation between the radial length L1 of the clearance and the length L2 of a contact surface between the balance disc and: l1 is 80% to 82% of L2.

10. The low-flow high-lift multistage centrifugal pump of claim 8, wherein: the positioning structure comprises a positioning groove, a positioning ring and a positioning sleeve, wherein the positioning groove is formed in the pump shaft close to the end cover of the non-driving end, the positioning ring matched with the positioning groove is arranged on the pump shaft and is in contact with one end of the balance disc adjusting ring, the positioning sleeve is sleeved on the periphery of the positioning ring, and the positioning sleeve is connected with the balance disc through the positioning sleeve.