CN112780579A

CN112780579A - Water pump

Info

Publication number: CN112780579A
Application number: CN202110093844.5A
Authority: CN
Inventors: 朱成浩; 张云霞
Original assignee: Jinan Dechuang Test Instrument Co ltd
Current assignee: Jinan Dechuang Test Instrument Co ltd
Priority date: 2021-01-23
Filing date: 2021-01-23
Publication date: 2021-05-11

Abstract

The invention relates to a water pump, which comprises a pump body, a first variable unit, a second variable unit and a third variable unit, wherein the pump body is provided with a first variable unit and a second variable unit; a first variable unit is arranged on the left side of the pump body; a second variable unit is arranged on the right side of the pump body; a third variable unit is arranged on the lower side of the pump body; the left side of the pump body is provided with an inlet A which is respectively communicated with inlets of the first variable unit, the second variable unit and the third variable unit; an outlet B communicated with outlets of the first variable unit, the second variable unit and the third variable unit is formed in the upper side of the pump body; the first variable unit, the second variable unit and the third variable unit are matched to change the flow of the outlet B; the invention is provided with three different variable units, and the working state of the variable units is controlled by the electric pole, so that the number of rotating impellers is changed, and the change of the outlet flow of the water pump is realized; the invention can adapt to various pipeline systems and different production tasks and process requirements; and the working is stable and the power loss is small.

Description

Water pump

Technical Field

The invention belongs to the technical field of fluid pumps, and particularly relates to a water pump.

Background

The water pump is a machine for conveying liquid or pressurizing liquid, and can be divided into a volumetric water pump, a vane pump and the like according to different working principles, and the vane pump can be divided into a centrifugal pump, an axial flow pump, a mixed flow pump and the like; the centrifugal pump works by utilizing the rotation of an impeller to enable liquid to generate centrifugal motion, and the working principle is as follows: after the liquid enters the pump shell, the flow velocity of the liquid is gradually reduced due to the gradual expansion of the flow channel in the volute-shaped pump shell, a part of kinetic energy is converted into static pressure energy, and then the liquid flows out along the discharge port at higher pressure. Meanwhile, a certain vacuum is formed at the center of the impeller due to the fact that liquid is thrown out, and the pressure at the liquid level is higher than that at the center of the impeller. Therefore, the liquid in the suction pipeline enters the pump under the action of pressure difference, the impeller rotates continuously, and the liquid is sucked and pressed out continuously.

Generally, the flow rate of a water pump may not be consistent with a pipeline system, or the flow rate of the pump needs to be adjusted due to the change of production tasks and process requirements, the simplest method for changing the flow rate of the centrifugal pump is to adjust the opening degree of an outlet valve of the pump, and the rotating speed is kept unchanged, but the method consumes the redundant energy of the centrifugal pump to maintain a certain supply amount, and the efficiency of the centrifugal pump is lost.

Disclosure of Invention

In order to solve the above problems, the present invention provides a water pump.

In order to achieve the above object, the present invention provides the following technical solution, including a pump body, a first variable unit, a second variable unit and a third variable unit; a first variable unit is arranged on the left side of the pump body; a second variable unit is arranged on the right side of the pump body; a third variable unit is arranged on the lower side of the pump body; the left side of the pump body is provided with an inlet A which is respectively communicated with inlets of the first variable unit, the second variable unit and the third variable unit; and an outlet B communicated with outlets of the first variable unit, the second variable unit and the third variable unit is arranged on the upper side of the pump body.

The first variable unit, the second variable unit and the third variable unit are matched to change the flow of the outlet B; when the first variable unit, the second variable unit and the third variable unit work simultaneously, the water pump is in a three-stage working state with the maximum flow; when only the first variable unit and the second variable unit work, the water pump is in a secondary working state with smaller flow; when only the first variable unit works, the water pump is in a first-stage working state with the minimum flow.

Preferably, the first variable unit comprises a first rotating shaft, a circular ring, a first electric pole, a first bevel gear and a first impeller; the first rotating shaft is rotatably connected in the pump body, and two identical baffles are arranged in the middle of the first rotating shaft; a ring which is rotatably connected with the first rotating shaft is arranged between the baffles, and a first push rod is arranged at the upper end of the ring; a first electric pole fixedly connected with the pump body is horizontally arranged on the upper side of the first rotating shaft, and the telescopic end of the first electric pole is fixedly connected to the left end face of the circular ring; a first helical gear is arranged at the right end of the first rotating shaft; the right part of the first rotating shaft can slide left and right and is arranged in the first impeller, and the first rotating shaft and the first impeller cannot rotate relatively; a first water suction port is formed in the left side of the first impeller and the pump body, and a first water outlet is formed in the upper side of the first impeller and the pump body.

Preferably, the second variable unit comprises a second bevel gear, a second rotating shaft, a second impeller, a first mounting cavity, a flow stopping assembly and a worm; the second rotating shaft is rotatably connected in the pump body, and the axis of the second rotating shaft is vertical to the axis of the first rotating shaft; the second bevel gear is fixedly connected to the second rotating shaft; the upper end of the second rotating shaft is fixedly connected with a second impeller; a second water suction port is formed at the lower side of the second impeller and the pump body, and a second water outlet is formed at the left side of the second impeller and the pump body; the second water outlet is communicated with the outlet B through a second outlet flow passage; a first mounting cavity is formed in the left side of the second outlet flow channel; a flow stopping assembly used for controlling the on-off of the second water outlet and the outlet B is arranged in the first mounting cavity; the lower end of the second rotating shaft is fixedly connected with a worm.

When the first electric pole extends out, the second bevel gear is meshed with the first bevel gear, and the flow stopping assembly opens the second outlet flow passage to enable the second water outlet to be communicated with the outlet B; when the first electric pole retracts, the second bevel gear is disengaged from the first bevel gear, and the flow stopping assembly closes the second outlet flow passage to enable the second water outlet to be not communicated with the outlet B any more.

Preferably, the flow stopping assembly comprises a flow stopping block, a second push rod and two tension springs; the flow stopping block is connected in the first mounting cavity in a sliding mode and can partition the second outlet flow channel where the flow stopping block is located; the lower end of the flow stopping block is provided with a second push rod in sliding connection with the pump body, one end of each tension spring is fixedly connected to the lower end of the flow stopping block, the other end of each tension spring is fixedly connected to the pump body, and the tension springs force the flow stopping block to move in the direction away from the second outlet flow channel; when the first electric pole retracts, the ring drives the first rotating shaft to move to the left, the first push rod curved surface part is contacted with the second push rod curved surface part, the flow stopping block is pushed to overcome the tension of the tension spring to move upwards until the flow stopping block is closed, and the second outlet flow passage enables the second water outlet and the outlet B not to be communicated.

Preferably, the third variable unit comprises a second mounting cavity, two second electric poles, two fixed blocks, a third rotating shaft, a rectangular mounting block, a third impeller and a worm wheel; a second installation cavity is formed in the lower side of the pump body, the two second electric poles are fixedly connected to two sides of the second installation cavity respectively, a fixed block is arranged at each telescopic end of each second electric pole, and two ends of the third rotating shaft are rotatably connected with the fixed blocks respectively; the middle part of the third rotating shaft is rotatably connected with a rectangular mounting block, the rectangular mounting block is connected in a sliding cavity in a sliding manner, and a third impeller fixedly connected with the third rotating shaft is arranged in the rectangular mounting block; a third water inlet which penetrates through the left side of the third impeller and the rectangular mounting block is formed, and a third water outlet which penetrates through the inner side of the third impeller and the rectangular mounting block is formed; a worm wheel fixedly connected with the third rotating shaft is arranged on the right side of the rectangular mounting block; when the two second electric poles retract, the worm wheel is meshed with the worm; when the two second electric poles are extended, the worm wheel is disengaged from the worm.

Preferably, a first inlet flow channel, a first outlet flow channel, a second inlet flow channel, a second outlet flow channel, a third inlet flow channel and a third outlet flow channel are arranged in the pump body; one end of the first inlet flow passage is communicated with the inlet A, and the other end of the first inlet flow passage is communicated with the first water suction port; one end of the first outlet flow passage is communicated with the first water outlet, and the other end of the first outlet flow passage is communicated with the outlet B; one end of the second inlet flow passage is communicated with the first water suction port, and the other end of the second inlet flow passage is communicated with the second water suction port; one end of the second outlet flow passage is communicated with the second water outlet, and the other end of the second outlet flow passage is communicated with the outlet B; one end of the third inlet flow passage is communicated with the inlet A, and the other end of the third inlet flow passage is communicated with the sliding cavity; one end of the third outlet flow passage is communicated with the sliding cavity, and the other end of the third outlet flow passage is communicated with the outlet B.

When the second pole stretches out, the rectangle installation piece slides to keeping away from the worm direction, the one end of third inlet channel and the one end of third outlet channel are plugged up to rectangle installation piece lateral wall shutoff, make third water sucking mouth and third inlet channel cut off not logical, and third delivery port and third outlet channel cut off not logical.

When the second pole retracts, the rectangular mounting block slides towards the direction close to the worm, so that the third water suction port is communicated with the third inlet runner, and the third water outlet is communicated with the third outlet runner.

Preferably, when the first electric pole extends out and the second electric pole retracts, the second bevel gear is meshed with the first bevel gear, the worm gear is meshed with the worm, the first rotating shaft rotates to enable the first impeller, the second impeller and the third impeller to rotate simultaneously, the first variable unit, the second variable unit and the third variable unit work simultaneously, and the water pump is in a three-stage working state.

Preferably, when the water pump is in a three-stage working state, the rotation of the first impeller transports water at the inlet A to the outlet B through the first inlet runner and the first outlet runner respectively; the rotation of the second impeller transports the water at the inlet A to the outlet B through the first inlet flow channel, the second inlet flow channel and the second outlet flow channel respectively; the rotation of the third impeller transports the water at the inlet A to the outlet B through the third inlet flow passage and the third outlet flow passage respectively, and the flow of the outlet B is maximum at the moment.

Preferably, when the first electric pole extends out and the second electric pole extends out, the worm wheel and the worm are disengaged, the third water suction port is not communicated with the third inlet flow channel, the third water outlet is not communicated with the third outlet flow channel, the first rotating shaft rotates to drive the first impeller and the second impeller to rotate, the first variable unit and the second variable unit work, and the water pump is in a secondary working state; the rotation of the first impeller transports the water at the inlet A to the outlet B through the first inlet flow channel and the first outlet flow channel respectively; the rotation of the second impeller transports the water at the inlet A to the outlet B through the first inlet flow channel, the second inlet flow channel and the second outlet flow channel respectively, and the flow of the outlet B is small.

Preferably, when the second electric pole extends out and the first electric pole retracts, the circular ring drives the first rotating shaft to move to the left, and the second bevel gear is disengaged from the first bevel gear; at the moment, the first rotating shaft rotates to only enable the first impeller to rotate, the first variable unit works, and the water pump is in a first-stage working state; the rotation of the first impeller transports the water at the inlet A to the outlet B through the first inlet flow passage and the first outlet flow passage respectively, and the flow of the outlet B is minimum at the moment.

Compared with the prior art, the invention has the advantages that:

the invention is provided with three different variable units, and the working state of the variable units is controlled by the electric pole, so that the number of rotating impellers is changed, and the change of the outlet flow of the water pump is realized; the invention can adapt to various pipeline systems and different production tasks and process requirements; and the working is stable and the power loss is small.

Drawings

FIG. 1 is a schematic diagram of the three-stage operation of the present invention;

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1 in accordance with the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 1 in a secondary operational state of the present invention;

FIG. 4 is a schematic diagram of a first-level operating state of the present invention.

The flow stopping block 351 is connected in the first mounting cavity 34 in a sliding mode and can block the second outlet flow channel 14 where the flow stopping block is located; the lower end of the flow stopping block 351 is provided with a second push rod 352 which is in sliding connection with the pump body 1, one end of each tension spring 353 is fixedly connected to the lower end of the flow stopping block 351, the other end of each tension spring 353 is fixedly connected to the pump body 1, and the tension springs 353 force the flow stopping block 351 to move towards the direction away from the second outlet flow channel 14; when the first electric pole 23 retracts, the ring 22 drives the first rotating shaft 21 to move leftwards, the curved surface part of the first push rod 221 contacts with the curved surface part of the second push rod 352, and the stop block 351 is pushed to move upwards against the pulling force of the tension spring 353 until the stop block 351 closes the second outlet flow passage 14, so that the second water outlet 332 is not communicated with the outlet B.

The third variable unit 4 comprises a second mounting cavity 41, two second electric poles 42, two fixed blocks 43, a third rotating shaft 44, a rectangular mounting block 45, a third impeller 46 and a worm wheel 47; a second mounting cavity 41 is formed in the lower side of the pump body 1, the two second electric poles 42 are fixedly connected to two sides of the second mounting cavity 41 respectively, a fixing block 43 is arranged at the telescopic end of each second electric pole 42, and two ends of the third rotating shaft 44 are rotatably connected with the fixing blocks 43 respectively; the middle part of the third rotating shaft 44 is rotatably connected with a rectangular mounting block 45, the rectangular mounting block 45 is slidably connected in the sliding cavity 451, and a third impeller 46 fixedly connected with the third rotating shaft 44 is arranged in the rectangular mounting block 45; a third water suction port 461 penetrating through the left side of the third impeller 46 and the rectangular mounting block 45, and a third water outlet 462 penetrating through the inner side of the third impeller 46 and the rectangular mounting block 45; a worm wheel 47 fixedly connected with the third rotating shaft 44 is arranged on the right side of the rectangular mounting block 45; when the two second electric poles 42 are retracted, the worm wheel 47 meshes with the worm 36; when the two second electric poles 42 are extended, the worm wheel 47 is disengaged from the worm 36.

A first inlet flow channel 11, a first outlet flow channel 12, a second inlet flow channel 13, a second outlet flow channel 14, a third inlet flow channel 15 and a third outlet flow channel 16 are arranged in the pump body 1; one end of the first inlet flow passage 11 is communicated with the inlet A, and the other end is communicated with the first water suction port 251; one end of the first outlet flow channel 12 is communicated with the first water outlet 252, and the other end is communicated with the outlet B; one end of the second inlet flow passage 13 is communicated with the first water suction port 251, and the other end is communicated with the second water suction port 331; one end of the second outlet flow channel 14 is communicated with the second water outlet 332, and the other end is communicated with the outlet B; one end of the third inlet flow passage 15 is communicated with the inlet A, and the other end is communicated with the sliding cavity 451; the third outlet flow passage 16 has one end communicating with the slide chamber 451 and the other end communicating with the outlet B.

When the second electric pole 42 extends, the rectangular mounting block 45 slides towards the direction away from the worm 36, and the side wall 452 of the rectangular mounting block blocks one end of the third inlet flow passage 15 and one end of the third outlet flow passage 16, so that the third water suction port 461 and the third inlet flow passage 15 are isolated and not communicated, and the third water outlet 462 and the third outlet flow passage 16 are isolated and not communicated.

When the second electric pole 42 is retracted, the rectangular mounting block 45 slides toward the worm 36, so that the third water suction opening 461 communicates with the third inlet flow passage 15, and the third water outlet 462 communicates with the third outlet flow passage 16.

When the first electric pole 23 extends out and the second electric pole 42 retracts, the second bevel gear 31 is meshed with the first bevel gear 24, the worm wheel 47 is meshed with the worm 36, the first rotating shaft 21 rotates to enable the first impeller 25, the second impeller 33 and the third impeller 46 to rotate simultaneously, at the moment, the first variable unit 2, the second variable unit 3 and the third variable unit 4 work simultaneously, and the water pump is in a three-stage working state.

When the water pump is in a three-stage working state, the rotation of the first impeller 25 enables water at the inlet A to flow through the first inlet respectively

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As shown in fig. 1-4, is a preferred embodiment of the present invention.

A water pump comprises a pump body 1, a first variable unit 2, a second variable unit 3 and a third variable unit 4; a first variable unit 2 is arranged on the left side of the pump body 1; a second variable unit 3 is arranged on the right side of the pump body 1; a third variable unit 4 is arranged on the lower side of the pump body 1; the left side of the pump body 1 is provided with an inlet A which is respectively communicated with inlets of the first variable unit 2, the second variable unit 3 and the third variable unit 4; and an outlet B communicated with outlets of the first variable unit 2, the second variable unit 3 and the third variable unit 4 is formed in the upper side of the pump body 1.

The first variable unit 2, the second variable unit 3 and the third variable unit 4 are matched to change the flow of the outlet B; when the first variable unit 2, the second variable unit 3 and the third variable unit 4 work simultaneously, the water pump is in a three-stage working state with the maximum flow; when only the first variable unit 2 and the second variable unit 3 work, the water pump is in a two-stage working state with small flow; when only the first variable unit 2 works, the water pump is in a first-stage working state with the minimum flow.

The first variable unit 2 comprises a first rotating shaft 21, a circular ring 22, a first electric pole 23, a first bevel gear 24 and a first impeller 25; the first rotating shaft 21 is rotatably connected in the pump body 1, and two identical baffles 211 are arranged in the middle of the first rotating shaft 21; a ring 22 rotatably connected with the first rotating shaft 21 is arranged between the baffles 211, and a first push rod 221 is arranged at the upper end of the ring 22; a first electric pole 23 fixedly connected with the pump body 1 is horizontally arranged on the upper side of the first rotating shaft 21, and the telescopic end of the first electric pole 23 is fixedly connected to the left end face of the circular ring 22; a first helical gear 24 is arranged at the right end of the first rotating shaft 21; the right part of the first rotating shaft 21 is arranged in the first impeller 25 in a left-right sliding manner, and the first rotating shaft 21 and the first impeller 25 cannot rotate relatively; the first suction port 251 is formed at the left side of the first impeller 25 and the pump body 1, and the first discharge port 252 is formed at the upper side of the first impeller 25 and the pump body 1.

The second variable unit 3 comprises a second bevel gear 31, a second rotating shaft 32, a second impeller 33, a first mounting cavity 34, a flow stopping assembly 35 and a worm 36; the second rotating shaft 32 is rotatably connected in the pump body 1, and the axis of the second rotating shaft 32 is perpendicular to the axis of the first rotating shaft 21; the second bevel gear 31 is fixedly connected to the second rotating shaft 32; the upper end of the second rotating shaft 32 is fixedly connected with a second impeller 33; a second water suction port 331 is formed at the lower side of the second impeller 33 and the pump body 1, and a second water outlet 332 is formed at the left side of the second impeller 33 and the pump body 1; the second water outlet 332 is communicated with the outlet B through a second outlet flow passage 14; a first mounting cavity 34 is arranged on the left side of the second outlet flow passage 14; a flow stopping assembly 35 for controlling the on-off of the second water outlet 332 and the outlet B is arranged in the first mounting cavity 34; a worm 36 is fixedly connected to the lower end of the second rotating shaft 32.

When the first electric pole 23 extends out, the second bevel gear 31 is engaged with the first bevel gear 24, and the flow stopping assembly 35 opens the second outlet flow passage 14 to enable the second water outlet 332 to be communicated with the outlet B; when the first electric pole 23 retracts, the second bevel gear 31 and the first bevel gear 24 are disengaged, and the flow stopping assembly 35 closes the second outlet flow passage 14, so that the second water outlet 332 and the outlet B are not communicated.

The flow stopping assembly 35 comprises a flow stopping block 351, a second push rod 352 and two tension springs 353; the flow stopping blocks 351 and the first outlet flow channel 12 are conveyed to an outlet B; the rotation of the second impeller 33 transports the water at the inlet a to the outlet B through the first inlet flow passage 11, the second inlet flow passage 13 and the second outlet flow passage 14, respectively; rotation of the third impeller 46 transports water from the inlet a to the outlet B via the third inlet flow passage 15 and the third outlet flow passage 6, respectively, where the outlet B has the greatest flow.

When the first electric pole 23 extends and the second electric pole 42 extends, the worm wheel 47 and the worm 36 are disengaged, the third water suction port 461 is not communicated with the third inlet flow passage 15, the third water outlet 462 is not communicated with the third outlet flow passage 16, at this time, the first rotating shaft 21 rotates to drive the first impeller 25 and the second impeller 33 to rotate, the first variable unit 2 and the second variable unit 3 work, and the water pump is in a second-stage working state; the rotation of the first impeller 25 transports the water at the inlet a to the outlet B via the first inlet flow channel 11 and the first outlet flow channel 12, respectively; the rotation of the second impeller 33 transports the water at the inlet a to the outlet B via the first inlet channel 11, the second inlet channel 13 and the second outlet channel 14, respectively, with a smaller flow at the outlet B.

When the second electric pole 42 extends out and the first electric pole 23 retracts, the circular ring 22 drives the first rotating shaft 21 to move leftwards, and the second bevel gear 31 and the first bevel gear 24 are disengaged; at the moment, the first rotating shaft 21 rotates to only enable the first impeller 25 to rotate, the first variable unit 2 works, and the water pump is in a first-stage working state; rotation of the first impeller 25 transports water from the inlet a to the outlet B via the first inlet channel 11 and the first outlet channel 12, respectively, with the outlet B having the smallest flow.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A water pump, characterized by: the water pump comprises a pump body (1), a first variable unit (2), a second variable unit (3) and a third variable unit (4); a first variable unit (2) is arranged on the left side of the pump body (1); a second variable unit (3) is arranged on the right side of the pump body (1); a third variable unit (4) is arranged on the lower side of the pump body (1); the left side of the pump body (1) is provided with an inlet A which is respectively communicated with inlets of the first variable unit (2), the second variable unit (3) and the third variable unit (4); an outlet B communicated with outlets of the first variable unit (2), the second variable unit (3) and the third variable unit (4) is formed in the upper side of the pump body (1);

the first variable unit (2), the second variable unit (3) and the third variable unit (4) are matched to change the flow of the outlet B; when the first variable unit (2), the second variable unit (3) and the third variable unit (4) work simultaneously, the water pump is in a three-stage working state with the maximum flow; when only the first variable unit (2) and the second variable unit (3) work, the water pump is in a secondary working state with small flow; when only the first variable unit (2) works, the water pump is in a first-stage working state with the minimum flow.

2. The water pump of claim 1, wherein: the first variable unit (2) comprises a first rotating shaft (21), a circular ring (22), a first electric pole (23), a first bevel gear (24) and a first impeller (25); the first rotating shaft (21) is rotatably connected in the pump body (1), and two identical baffles (211) are arranged in the middle of the first rotating shaft (21); a circular ring (22) rotationally connected with the first rotating shaft (21) is arranged between the baffles (211), and a first push rod (221) is arranged at the upper end of the circular ring (22); a first electric pole (23) fixedly connected with the pump body (1) is horizontally arranged on the upper side of the first rotating shaft (21), and the telescopic end of the first electric pole (23) is fixedly connected to the left end face of the circular ring (22); a first helical gear (24) is arranged at the right end of the first rotating shaft (21); the right part of the first rotating shaft (21) can slide left and right and is arranged in the first impeller (25), and the first rotating shaft (21) and the first impeller (25) cannot rotate relatively; a first water suction opening (251) is formed on the left side of the first impeller (25) and the pump body (1), and a first water outlet (252) is formed on the upper side of the first impeller (25) and the pump body (1).

3. The water pump of claim 2, wherein: the second variable unit (3) comprises a second bevel gear (31), a second rotating shaft (32), a second impeller (33), a first mounting cavity (34), a flow stopping assembly (35) and a worm (36); the second rotating shaft (32) is rotatably connected in the pump body (1), and the axis of the second rotating shaft (32) is vertical to the axis of the first rotating shaft (21); the second bevel gear (31) is fixedly connected to the second rotating shaft (32); the upper end of the second rotating shaft (32) is fixedly connected with a second impeller (33); a second water suction port (331) is formed at the lower side of the second impeller (33) and the pump body (1), and a second water outlet (332) is formed at the left side of the second impeller (33) and the pump body (1); the second water outlet (332) is communicated with the outlet B through a second outlet flow passage (14); a first mounting cavity (34) is formed in the left side of the second outlet flow channel (14); a flow stopping assembly (35) used for controlling the connection and disconnection of the second water outlet (332) and the outlet B is arranged in the first mounting cavity (34); the lower end of the second rotating shaft (32) is fixedly connected with a worm (36);

when the first electric pole (23) extends out, the second bevel gear (31) is meshed with the first bevel gear (24), and the flow stopping assembly (35) opens the second outlet flow passage (14) to enable the second water outlet (332) to be communicated with the outlet B; when the first electric pole (23) retracts, the second bevel gear (31) and the first bevel gear (24) are disengaged, and the flow stopping assembly (35) closes the second outlet flow passage (14) to ensure that the second water outlet (332) is not communicated with the outlet B any more.

4. The water pump of claim 3, wherein: the flow stopping assembly (35) comprises a flow stopping block (351), a second push rod (352) and two tension springs (353); the flow stopping block (351) is connected in the first mounting cavity (34) in a sliding mode, and the second outlet flow channel (14) where the flow stopping block (351) is located can be isolated; the lower end of the flow stopping block (351) is provided with a second push rod (352) in sliding connection with the pump body (1), one end of each tension spring (353) is fixedly connected to the lower end of the flow stopping block (351), the other end of each tension spring (353) is fixedly connected to the pump body (1), and the tension springs (353) force the flow stopping block (351) to move in the direction away from the second outlet flow channel (14); when the first electric pole (23) retracts, the circular ring (22) drives the first rotating shaft (21) to move leftwards, the curved surface part of the first push rod (221) is contacted with the curved surface part of the second push rod (352), the flow stopping block (351) is pushed to overcome the tension of the tension spring (353) to move upwards, and the flow stopping block (351) closes the second outlet flow passage (14) until the second outlet (332) is not communicated with the outlet B.

5. The water pump according to claim 4, characterized in that the third variable unit (4) comprises a second mounting chamber (41), two second electric poles (42), two fixed blocks (43), a third rotating shaft (44), a rectangular mounting block (45), a third impeller (46) and a worm wheel (47); a second mounting cavity (41) is formed in the lower side of the pump body (1), the two second electric poles (42) are fixedly connected to two sides of the second mounting cavity (41) respectively, a fixing block (43) is arranged at the telescopic end of each second electric pole (42), and two ends of a third rotating shaft (44) are rotatably connected with the fixing blocks (43) respectively; a rectangular mounting block (45) is rotatably connected to the middle of the third rotating shaft (44), the rectangular mounting block (45) is slidably connected into the sliding cavity (451), and a third impeller (46) fixedly connected with the third rotating shaft (44) is arranged in the rectangular mounting block (45); a third water suction port (461) which penetrates through the left side of the third impeller (46) and the rectangular mounting block (45) is formed, and a third water outlet (462) which penetrates through the inner side of the third impeller (46) and the rectangular mounting block (45) is formed; a worm wheel (47) fixedly connected with the third rotating shaft (44) is arranged on the right side of the rectangular mounting block (45); when the two second electric poles (42) retract, the worm wheel (47) meshes with the worm (36); when the two second electric poles (42) are extended, the worm wheel (47) is disengaged from the worm (36).

6. A water pump according to claim 5, characterized in that a first inlet channel (11), a first outlet channel (12), a second inlet channel (13), a second outlet channel (14), a third inlet channel (15) and a third outlet channel (16) are provided in the pump body (1); one end of the first inlet flow channel (11) is communicated with the inlet A, and the other end of the first inlet flow channel is communicated with the first water suction port (251); one end of the first outlet flow channel (12) is communicated with the first water outlet (252), and the other end of the first outlet flow channel is communicated with the outlet B; one end of the second inlet flow channel (13) is communicated with the first water suction port (251), and the other end of the second inlet flow channel is communicated with the second water suction port (331); one end of the second outlet flow channel (14) is communicated with the second water outlet (332), and the other end of the second outlet flow channel is communicated with the outlet B; one end of the third inlet flow passage (15) is communicated with the inlet A, and the other end of the third inlet flow passage is communicated with the sliding cavity (451); one end of the third outlet flow channel (16) is communicated with the sliding cavity (451), and the other end is communicated with the outlet B;

when the second electric pole (42) extends out, the rectangular mounting block (45) slides towards the direction far away from the worm (36), the side wall (452) of the rectangular mounting block blocks one end of the third inlet flow channel (15) and one end of the third outlet flow channel (16), so that the third water suction port (461) and the third inlet flow channel (15) are blocked and are blocked, and the third water outlet (462) and the third outlet flow channel (16) are blocked and not blocked;

when the second electric pole (42) retracts, the rectangular mounting block (45) slides towards the direction close to the worm (36), so that the third water suction port (461) is communicated with the third inlet flow passage (15), and the third water outlet port (462) is communicated with the third outlet flow passage (16).

7. The water pump according to claim 6, wherein when the first electric pole (23) is extended and the second electric pole (42) is retracted, the second bevel gear (31) is engaged with the first bevel gear (24), the worm gear (47) is engaged with the worm (36), the first rotating shaft (21) rotates to rotate the first impeller (25), the second impeller (33) and the third impeller (46) simultaneously, and the first variable unit (2), the second variable unit (3) and the third variable unit (4) are operated simultaneously, and the water pump is in a three-stage operation state.

8. The water pump according to claim 7, wherein the rotation of the first impeller (25) transports water from the inlet a to the outlet B via the first inlet flow channel (11) and the first outlet flow channel (12), respectively, when the water pump is in a three-stage operation; the rotation of the second impeller (33) transports the water at the inlet A to the outlet B through the first inlet flow channel (11), the second inlet flow channel (13) and the second outlet flow channel (14) respectively; the rotation of the third impeller (46) transports the water from the inlet A to the outlet B through the third inlet flow passage (15) and the third outlet flow passage (6), respectively, and the flow of the outlet B is maximum at the moment.

9. The water pump of claim 8, wherein when the first electric pole (23) is extended and the second electric pole (42) is extended, the worm wheel (47) and the worm (36) are disengaged, the third water suction port (461) and the third inlet flow passage (15) are not communicated, the third water outlet port (462) and the third outlet flow passage (16) are not communicated, and when the first rotating shaft (21) rotates to drive the first impeller (25) and the second impeller (33) to rotate, the first variable unit (2) and the second variable unit (3) work, and the water pump is in a secondary working state; the rotation of the first impeller (25) transports the water at the inlet A to the outlet B through the first inlet flow channel (11) and the first outlet flow channel (12) respectively; the rotation of the second impeller (33) transports the water at the inlet A to the outlet B through the first inlet flow passage (11), the second inlet flow passage (13) and the second outlet flow passage (14), and the flow of the outlet B is small.

10. The pump according to claim 9, characterized in that when the second electric pole (42) is extended and the first electric pole (23) is retracted, the ring (22) drives the first rotating shaft (21) to move to the left, and the second bevel gear (31) and the first bevel gear (24) are disengaged; at the moment, the first rotating shaft (21) rotates to only enable the first impeller (25) to rotate, the first variable unit (2) works, and the water pump is in a first-stage working state; the rotation of the first impeller (25) transports water from the inlet a to the outlet B via the first inlet flow channel (11) and the first outlet flow channel (12), respectively, with the outlet B having a minimum flow.