CN210660600U

CN210660600U - Multistage centrifugal pump

Info

Publication number: CN210660600U
Application number: CN201921223756.7U
Authority: CN
Inventors: 汤方平; 邹红美; 李宗宝; 胡秋瑾; 周颖; 柏周; 张文鹏; 刘海宇
Original assignee: Yangzhou University
Current assignee: Yangzhou University
Priority date: 2019-07-31
Filing date: 2019-07-31
Publication date: 2020-06-02
Anticipated expiration: 2029-07-31

Abstract

The utility model provides a multistage centrifugal pump in the hydraulic engineering equipment technical field, including feed liquor end bearing bracket, be connected with the pivot on the feed liquor end bearing bracket, be connected with the feed liquor pump head in the pivot of feed liquor end bearing bracket one side, the feed liquor pump head is kept away from one side of feed liquor end bearing bracket and is connected the one end of driving a plurality of groups of packing box modules that the pivot rotated, be connected with out the liquid pump head in the pivot of the packing box module other end, be connected with the impeller on the pivot between feed liquor pump head and packing box module, between adjacent group packing box module and between packing box module and the play liquid pump head, between packing box module and feed liquor pump head, between adjacent group packing box module, form respectively between packing box module and the play liquid pump head and hold chamber one, hold chamber two and hold chamber three that can hold liquid, open the liquid outlet on the side that the relative impeller; the utility model discloses a load is even around the pivot, and noise at work is little.

Description

Multistage centrifugal pump

Technical Field

The utility model belongs to the technical field of hydraulic engineering equipment, in particular to multistage centrifugal pump.

Background

The multistage centrifugal pump is a medium conveying device, wherein flowing media (gas and liquid, or a mixture of suspended particles and gas or liquid) enter from the root (inlet) of a rotating shaft of a blade, the media obtain centrifugal force by virtue of a high-speed rotating blade to generate high pressure and flow out from a pressure relief opening (outlet). The whole multi-stage centrifugal pump integrates more than two pumps with the same function, and the fluid channel structure is characterized in that a medium pressure relief opening of the first stage is communicated with an inlet of the second stage, a medium pressure relief opening of the second stage is communicated with an inlet of the third stage, and the multi-stage centrifugal pump is formed by a mechanism connected in series. The multistage centrifugal pump has the significance of greatly improving the set pressure, has the characteristics of small floor area, stable operation, small vibration, long service life and the like due to the fact that the center of gravity of the pump is coincident with the center of a pump foot, is widely applied to agriculture, industrial production and daily life of people, and is particularly applied to north-south water transfer work in China.

Most of motors adopted by the existing multistage centrifugal pump are standard industrial motors, most of the motors run at a power frequency rotating speed at a constant speed, and in practical application, a water pump system does not need to work at a rated flow and a rated lift in most of working time and needs to work at a partial load working condition, namely the flow required by the actual water pump system is lower than the rated flow or the required lift is lower than the rated lift, and the operation can be realized by reducing the rotating speed of the centrifugal pump. In the prior art, in order to solve the technical problem that the rotating speed of the centrifugal pump is not adjustable, the name of the centrifugal pump is 'silent multistage centrifugal pump', the publication number is CN 107575392A, the publication number is 2018.01.12 Chinese utility model patent, the centrifugal pump comprises a pump body, a pump shaft is axially arranged in the pump body, an impeller is rotatably connected to the pump shaft, a liquid cooling motor is axially arranged at the upper end of the pump body through a motor bracket, a motor shaft of the liquid cooling motor is arranged in the middle of a motor inner shell, the liquid cooling motor drives the motor shaft to rotate, the end part of the motor shaft extending out of the motor outer shell is connected with a coupler, the output end of the coupler is connected with the pump shaft, the cooling motor transmits power to the pump shaft through the coupler, the liquid cooling motor is a motor which integrates a variable frequency controller and a motor and is cooled through liquid, in the design, therefore, in the centrifugal pump, the frequency conversion and heat cooling effects can be achieved only by adopting a specific liquid cooling motor, the price is high, the maintenance and replacement cost of the motor is high in the aspect of maintenance cost, in addition, a special power transmission part is required to be adopted to transmit power, the noise is low, and the load borne by the pump shaft is uneven.

SUMMERY OF THE UTILITY MODEL

To the defect among the prior art, the utility model discloses an it bears the inhomogeneous technical problem of load to solve among the prior art epaxial, the utility model provides a multistage centrifugal pump, the utility model provides a load is even around the pivot, reduces noise at work.

The purpose of the utility model is realized like this: a multistage centrifugal pump comprises a liquid inlet end bearing support and a plurality of groups of stuffing box modules, wherein a rotatable rotating shaft is connected onto the liquid inlet end bearing support, the groups of stuffing box modules are used for driving the rotating shaft to rotate, a liquid inlet pump head with a liquid inlet cavity is fixedly connected to one side of the liquid inlet end bearing support in the left-right direction, the liquid inlet pump head is connected with the rotating shaft, an inlet is formed in the downward end of the liquid inlet pump head, one side, far away from the liquid inlet end bearing support, of the liquid inlet pump head is connected with one end of the foremost group of stuffing box modules, the other end of one group of stuffing box modules is connected with one end of the other group of stuffing box modules, a liquid outlet pump head with a liquid outlet cavity is connected onto the rotating shaft of the outward end of the rearmost group of stuffing box modules, an impeller is respectively connected onto the rotating shaft between the liquid inlet pump head and the foremost group of stuffing box, the liquid inlet pump head is provided with a liquid inlet communicated with the liquid inlet cavity at one side opposite to the front group of stuffing box modules, a first accommodating cavity capable of accommodating liquid is formed between the front group of stuffing box modules and the liquid inlet pump head, a second accommodating cavity capable of accommodating liquid is formed between the adjacent groups of stuffing box modules, a third accommodating cavity capable of accommodating liquid is formed between the rear group of stuffing box modules and the liquid outlet pump head, a runner inlet is formed at one side of the impeller opposite to the liquid inlet pump head, a plurality of centrifugal runners are distributed on the impeller, a runner outlet is formed in the periphery of the impeller, one end of each centrifugal runner is communicated with the runner inlet, the other end of each centrifugal runner is communicated with the runner outlet, a liquid outlet is formed at one side opposite to the impeller, an upward end of the liquid outlet pump head is provided with an outlet, and the liquid outlet and the.

In the utility model, the inlet of the liquid inlet pump head is a centrifugal pump low-pressure water pipe joint, and the outlet of the liquid outlet pump head is a centrifugal pump high-pressure water pipe joint; when the centrifugal pump works, the stuffing box module acts, the rotating shaft rotates, the rotating shaft drives each impeller to rotate, water enters the liquid inlet cavity from an inlet of the liquid inlet pump head, the water entering the liquid inlet cavity enters the first accommodating cavity from the liquid inlet, the impeller at the forefront end rotates, the water enters the centrifugal flow channel from the inlet of the flow channel, high-pressure water is output from the outlet of the flow channel, the high-pressure water enters the second accommodating cavity at the forefront end, the corresponding impeller in the second accommodating cavity throws out the high-pressure water, the high-pressure water enters the second accommodating cavity at the rear end, the impeller in the second accommodating cavity at the rearmost end throws out the high-pressure water, the high-pressure water enters the third accommodating cavity, the water entering the third accommodating cavity is thrown out by; the packing box modules directly drive the rotating shaft to rotate, so that the load acting on the rotating shaft is uniform, the working vibration and noise of the whole machine are reduced, and the overall length of the centrifugal pump is shortened; can be applied to the water supply work.

In order to further realize the output of high-pressure water, the stuffing box module comprises a stuffing box unit I, a motor and a stuffing box unit II, the motor comprises a motor shell and a rotor in the motor shell, one side of the motor shell is fixedly connected with the stuffing box unit I, the other side of the motor shell is fixedly connected with the stuffing box unit II, and the rotor is connected with the rotating shaft; a plurality of coaxially arranged liquid through holes I, liquid through holes II and liquid through holes III are respectively distributed on the stuffing box unit I, the motor shell and the stuffing box unit II; in the adjacent groups of stuffing box modules, a stuffing box unit II of one group of stuffing box modules is fixedly connected with a stuffing box unit I of the other group of stuffing box modules; in the design, high-pressure water output by the impeller sequentially passes through the first liquid through hole, the second liquid through hole and the third liquid through hole to enter the second accommodating cavity behind the impeller, and high-pressure water output by the impeller of the second accommodating cavity at the rearmost end sequentially passes through the first liquid through hole, the second liquid through hole and the third liquid through hole to enter the third accommodating cavity, so that water output is realized; the stuffing box unit I and the stuffing box unit II prevent water from entering the motor, prevent the short circuit of the motor and ensure the working reliability.

In order to further realize the rotation of the rotating shaft, four groups of stuffing box modules are arranged, and when viewed from the direction from the foremost stuffing box module to the rearmost stuffing box module, motors in the four groups of stuffing box modules are respectively a motor I, a motor II, a motor III and a motor IV.

In order to further realize the rotation speed adjustment of the rotating shaft, the control unit is further included, a relay A1, a relay A2, a relay A3 and a relay A4 are respectively arranged in the motor I, the motor II, the motor III and the motor IV, the control unit controls the switches of the relay A1, the relay A2, the relay A3 and the relay A4, the stator winding of the motor I comprises a coil winding U1, a coil winding V1 and a coil winding W1, the stator winding of the motor II comprises a coil winding U2, a coil winding V2 and a coil winding W2, the stator winding of the motor III comprises a coil winding U3, a coil winding V3 and a coil winding W3, the stator winding of the motor IV comprises a coil winding U4, a coil winding V4 and a coil winding W4, the input ends of the coil winding U4, the coil winding V4 and the coil winding W4 are respectively connected with the three-phase line of the three-phase terminal box, and the output ends of the coil winding U4, the coil, the input ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with a first terminal of the relay A1, the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with a second terminal of the relay A1, when the relay A1 is in an open state, the common end of the relay A1 and the first terminal of the relay A1 are electrified, and the second terminal is not electrified; when the relay A1 is in a closed state, the common terminal of the relay A1 and the second terminal of the relay A1 are electrified, and the first terminal is not electrified; the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are also connected with the common end of the relay A2; the input ends of the coil winding U3, the coil winding V3 and the coil winding W3 are connected with a first terminal of the relay A2, the output ends of the coil winding U3, the coil winding V3 and the coil winding W3 are connected with a second terminal of the relay A2, when the relay A2 is in an open state, the common end of the relay A2 and the first terminal of the relay A2 are electrified, and the second terminal is not electrified; when the relay A2 is in a closed state, the common terminal of the relay A2 and the second terminal of the relay A2 are electrified, and the first terminal is not electrified; the output ends of the coil winding U3, the coil winding V3 and the coil winding W3 are also connected with the common end of the relay A3; the input ends of the coil winding U4, the coil winding V4 and the coil winding W4 are connected with a first terminal of the relay A3, the output ends of the coil winding U4, the coil winding V4 and the coil winding W4 are connected with a second terminal of the relay A3, when the relay A3 is in an open state, the common end of the relay A3 and the first terminal of the relay A3 are electrified, and the second terminal is not electrified; when the relay A3 is in a closed state, the common terminal of the relay A3 and the second terminal of the relay A3 are electrified, and the first terminal is not electrified; the output terminals of the coil winding U4, the coil winding V4, and the coil winding W4 are also connected to a common terminal of the relay a4, and the first terminal and the second terminal of the relay a4 are grounded, respectively.

In order to further improve the sealing performance between the first stuffing box unit and the motor shell and between the second stuffing box unit and the motor shell, connecting steps are arranged on one sides, opposite to the motor, of the first stuffing box unit and the second stuffing box unit, the first stuffing box unit and the second stuffing box unit are pressed in the motor shell through the connecting steps, the second stuffing box unit is pressed in the motor shell through the connecting steps, and the connecting steps are in interference fit with the motor shell; in addition, stuffing seals are adopted between the stuffing box unit I and the stuffing box unit II and the rotating shaft.

As a further improvement of the utility model, one side of the liquid inlet end bearing support in the left-right direction is fixedly connected with a liquid inlet stuffing box unit, and one side of the liquid inlet stuffing box unit, which is far away from the liquid inlet end bearing support, is fixedly connected with a liquid inlet pump head; the liquid inlet stuffing box unit prevents high-pressure water flow in the pump body from rushing out of the pump during positive pressure and prevents air from entering the pump during negative pressure.

As a further improvement, the one end fixedly connected with of going out the liquid impeller is kept away from to the liquid pump head goes out liquid stuffing box unit, goes out liquid stuffing box unit and keeps away from out liquid pump head place one end fixedly connected with and goes out liquid bearing bracket.

In order to further improve the reliability of the rotation of the rotating shaft, the other side of the liquid inlet end bearing support in the left-right direction is fixedly connected with a liquid inlet bearing end cover, the liquid outlet end bearing support is far away from one end of the liquid outlet stuffing box unit, the liquid inlet bearing end cover is fixedly connected with one end of the rotating shaft, the one end of the rotating shaft is rotatably connected onto the liquid inlet end bearing support through the liquid inlet bearing, and the other end of the rotating shaft is rotatably connected onto the liquid outlet end bearing support through.

Drawings

Fig. 1 is a structural view of the present invention.

Fig. 2 is a structural diagram of the impeller of the present invention.

Fig. 3 is a side view of the impeller of the present invention.

Fig. 4 is a structural diagram of the liquid feeding pump head of the present invention.

Fig. 5 is a structural diagram of the liquid discharge pump head of the present invention.

Fig. 6 is a front view of a stuffing box unit i in the present invention.

Fig. 7 is a side view of a stuffing box unit i according to the present invention.

Fig. 8 is a schematic diagram of a circuit structure in which n motors are connected according to the present invention.

Fig. 9 is a schematic diagram of a circuit structure in which 4 motors are connected according to the present invention.

Fig. 10 is a schematic structural diagram of a stuffing box module according to the present invention.

Fig. 11 is a schematic diagram of a circuit structure connected to the first motor according to the present invention.

In the figure: the liquid inlet end of the liquid inlet box unit is provided with a bearing support 1, a liquid inlet bearing 2, a liquid inlet bearing 3, a liquid inlet bearing end cover 4, a liquid inlet balance disc 5, a liquid inlet stuffing box unit 6, a liquid inlet pump head 601, a liquid inlet cavity 602, a liquid inlet 603, an impeller 7, a flow channel 701 inlet, a centrifugal flow channel 702, a flow channel 703 outlet, a stuffing box module 8, a motor 801, a stator 801a, a motor housing 801b, a rotor 801c, a stuffing box unit 802, an 802a connecting step, a stuffing box unit 803, a liquid through hole I9, a liquid through hole II 10, a liquid through hole III 11, a liquid outlet pump head 12, a liquid outlet 1201, a liquid outlet cavity 1202, a liquid outlet 1203 outlet, a liquid outlet stuffing box unit 13, a liquid outlet.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1 to 11, a multistage centrifugal pump comprises a liquid inlet bearing support 1 and a plurality of groups of stuffing modules 8, the liquid inlet bearing support 1 is connected with a rotatable rotating shaft 17, the plurality of groups of stuffing modules 8 are used for driving the rotating shaft 17 to rotate, the right side of the liquid inlet bearing support 1 is fixedly connected with a liquid inlet pump head 6 with a liquid inlet cavity 602, the liquid inlet pump head 6 is connected with the rotating shaft 17, the downward end of the liquid inlet pump head 6 is provided with an inlet 601, one side of the liquid inlet pump head 6, which is far away from the liquid inlet bearing support 1, is connected with one end of the leftmost group of stuffing modules 8, the other end of one group of stuffing modules 8 is connected with one end of the other group of stuffing modules 8, the outward end of the rightmost group of stuffing modules 8 is connected with a liquid outlet pump head 12 with a liquid outlet cavity 1202, and a space between the liquid inlet pump head 6 and, The rotating shafts 17 between the adjacent groups of stuffing box modules 8 and between the rightmost group of stuffing box modules 8 and the liquid outlet pump head 12 are respectively connected with an impeller 7, one side of the liquid inlet pump head 6, which is opposite to the leftmost group of stuffing box modules 8, is provided with a liquid inlet 603 communicated with a liquid inlet cavity 602, a first accommodating cavity capable of accommodating liquid is formed between the leftmost group of stuffing box modules 8 and the liquid inlet pump head 6, a second accommodating cavity capable of accommodating liquid is formed between the adjacent groups of stuffing box modules 8, a third accommodating cavity capable of accommodating liquid is formed between the rightmost group of stuffing box modules 8 and the liquid outlet pump head 12, one side of the impeller 7, which is opposite to the liquid inlet pump head 6, is provided with a flow channel inlet 701, a plurality of centrifugal flow channels 702 are distributed on the impeller 7, the periphery of the impeller 7 is provided with a centrifugal flow channel 703, one end of the centrifugal flow channel 702 is communicated with the flow channel inlet, a liquid outlet 1201 is arranged on one side of the liquid outlet pump head 12, which is opposite to the impeller 7, an outlet 1203 is arranged at the upward end of the liquid outlet pump head 12, and the liquid outlet 1201 and the outlet 1203 are both communicated with the liquid outlet cavity 1202; the right side of the liquid inlet end bearing support 1 is fixedly connected with a liquid inlet stuffing box unit 5, a rotating shaft 17 on one side, opposite to the liquid inlet end bearing support 1, of the liquid inlet stuffing box unit 5 is connected with a liquid inlet balance disc 4 through a flat key, the liquid inlet balance disc 4 is fixedly connected with the liquid inlet stuffing box unit 5, and one side, away from the liquid inlet end bearing support 1, of the liquid inlet stuffing box unit 5 is fixedly connected with a liquid inlet pump head 6; a liquid outlet stuffing box unit 13 is fixedly connected to one end of the liquid outlet pump head 12, which is far away from the liquid outlet impeller 7, a liquid outlet balance disc 14 is connected to a rotating shaft 17 on one side of the liquid outlet stuffing box unit 13, which is opposite to the liquid outlet end bearing support 15, through a flat key, the liquid outlet balance disc 14 is fixedly connected with the liquid outlet stuffing box unit 13, and a liquid outlet bearing 18 support is fixedly connected to one end of the liquid outlet stuffing box unit 13, which is far away from the liquid outlet pump head 12; the other side of the liquid inlet end bearing support 1 in the left-right direction is fixedly connected with a liquid inlet bearing end cover 3, one end of the liquid outlet end bearing support 15, which is far away from the liquid outlet stuffing box unit 13, is fixedly connected with a liquid outlet bearing 18 end cover 16, one end of a rotating shaft 17 is rotatably connected to the liquid inlet end bearing support 1 through a liquid inlet bearing 2, and the other end of the rotating shaft 17 is rotatably connected to the liquid outlet end bearing support 15 through a liquid outlet bearing 18.

In order to further realize the output of high-pressure water, the stuffing box module 8 comprises a stuffing box unit I802, a motor 801 and a stuffing box unit II 803, the motor 801 comprises a motor shell 801b and a rotor 801c in the motor shell 801b, one side of the motor shell 801b is fixedly connected with the stuffing box unit I802, the other side of the motor shell 801b is fixedly connected with the stuffing box unit II 803, and the rotor 801c is connected with the rotating shaft 17; a plurality of coaxially arranged liquid through holes I9, liquid through holes II 10 and liquid through holes III 11 are respectively arranged on the stuffing box unit I802, the motor shell 801b and the stuffing box unit II 803; in the adjacent groups of stuffing boxes 8, a second stuffing box unit 803 of one group of stuffing boxes 8 is fixedly connected with a first stuffing box unit 802 of another group of stuffing boxes 8;

in order to further realize the rotation of the rotating shaft 17, the device also comprises a control unit, wherein n groups (shown in figure 8) are arranged on the stuffing box module 8, n is more than or equal to 4 and is an even number; the motors 801 in the n groups of stuffing boxes 8 are respectively a motor I, a motor II, …, a motor n-1 and a motor n, relays A1, A2, A …, An-1 and An are respectively arranged in the motors I, II, …, n-1 and n, the stator 801a winding of the motor I comprises a coil winding U1, a coil winding V1 and a coil winding W1, the stator 801a winding of the motor II comprises a coil winding U2, a coil winding V2 and coil windings W2, …, the stator 801a winding of the motor n-1 comprises a coil winding Un-1, a coil winding Vn-1 and a coil winding Wn-1, the stator 801a winding of the motor n comprises a coil winding Un, a coil winding Vn and a coil winding W n, a coil winding U1, a coil winding V1 and An input end of the coil winding W1 are respectively connected with a three-phase line junction box of three phases, the output ends of the coil winding U1, the coil winding V1 and the coil winding W1 are connected with the common end of the relay A1, the input ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with the first terminal of the relay A1, the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with the second terminal of the relay A1, and when the relay A1 is in an open state, the common end of the relay A1 and the first terminal of the relay A1 are electrified, and the second terminal is not electrified; when the relay A1 is in a closed state, the common terminal of the relay A1 and the second terminal of the relay A1 are electrified, and the first terminal is not electrified; the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are also connected with the common end of the relay A2; the input ends of the coil winding Un-1, the coil winding Vn-1 and the coil winding Wn-1 are connected with a first terminal of the relay An-2, the output ends of the coil winding Un-1, the coil winding Vn-1 and the coil winding Wn-1 are connected with a second terminal of the relay An-2, when the relay An-2 is in An open state, the common end of the relay An-2 is connected with the first terminal of the relay An-2, and the second terminal of the relay An-2 is not electrified; when the relay An-2 is in a closed state, the common end of the relay An-2 is connected with the second terminal of the relay An-2, and the first terminal of the relay An-2 is not electrified; the second terminal of the relay An-2 is also connected with the common end of the relay An-1; the input ends of the coil winding Un, the coil winding Vn and the coil winding W n are connected with a first terminal of the relay An-1, the output ends of the coil winding Un, the coil winding Vn and the coil winding W n are connected with a common end of the relay An, the first terminal and a second terminal of the relay An are respectively grounded, and the common end of the relay An is further connected with a second terminal of the relay An-1.

For further convenience of understanding, in the present embodiment, the stuffing box modules 8 are provided with four groups (as shown in fig. 9), and when viewed from the direction from the frontmost stuffing box module 8 to the rearmost stuffing box module 8, the motors 801 in the four groups of stuffing box modules 8 are respectively a motor one, a motor two, a motor three, and a motor four; the first motor, the second motor, the third motor and the fourth motor are respectively provided with a relay A1, a relay A2, a relay A3 and a relay A4, the control unit controls the switches of the relay A1, the relay A2, the relay A3 and the relay A4, the stator 801a winding of the first motor comprises a coil winding U1, a coil winding V1 and a coil winding W1, the stator 801a winding of the second motor comprises a coil winding U2, a coil winding V2 and a coil winding W2, the stator 801a winding of the third motor comprises a coil winding U3, a coil winding V3 and a coil winding W3, the stator 801a winding of the fourth motor comprises a coil winding U4, a coil winding V4 and a coil winding W4, the input ends of the coil winding U1, the coil winding V1 and the coil winding W1 are respectively connected with three phase lines of a three phase line of a three phase terminal box, the output ends of the coil winding U1, the coil winding V1 and the coil winding W1 are connected with a common end 1 of, the input ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with a first terminal of the relay A1, the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with a second terminal of the relay A1, when the relay A1 is in an open state, the common end of the relay A1 and the first terminal of the relay A1 are electrified, and the second terminal is not electrified; when the relay A1 is in a closed state, the common terminal of the relay A1 and the second terminal of the relay A1 are electrified, and the first terminal is not electrified; the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are also connected with the common end of the relay A2; the input ends of the coil winding U3, the coil winding V3 and the coil winding W3 are connected with a first terminal of the relay A2, the output ends of the coil winding U3, the coil winding V3 and the coil winding W3 are connected with a second terminal of the relay A2, when the relay A2 is in an open state, the common end of the relay A2 and the first terminal of the relay A2 are electrified, and the second terminal is not electrified; when the relay A2 is in a closed state, the common terminal of the relay A2 and the second terminal of the relay A2 are electrified, and the first terminal is not electrified; the output ends of the coil winding U3, the coil winding V3 and the coil winding W3 are also connected with the common end of the relay A3; the input ends of the coil winding U4, the coil winding V4 and the coil winding W4 are connected with a first terminal of the relay A3, the output ends of the coil winding U4, the coil winding V4 and the coil winding W4 are connected with a second terminal of the relay A3, when the relay A3 is in an open state, the common end of the relay A3 and the first terminal of the relay A3 are electrified, and the second terminal is not electrified; when the relay A3 is in a closed state, the common terminal of the relay A3 and the second terminal of the relay A3 are electrified, and the first terminal is not electrified; the output terminals of the coil winding U4, the coil winding V4, and the coil winding W4 are also connected to a common terminal of the relay a4, and the first terminal and the second terminal of the relay a4 are grounded, respectively.

In order to further improve the sealing performance between the first stuffing box unit 802 and the second stuffing box unit 803 and the motor housing 801b, connecting steps 802a are arranged on the sides, opposite to the motor 801, of the first stuffing box unit 802 and the second stuffing box unit 803, the first stuffing box unit 802 is pressed in the motor housing 801b through the connecting steps 802a, the second stuffing box unit 803 is pressed in the motor housing 801b through the connecting steps 802a, and the connecting steps 802a and the motor housing 801b are in interference fit; in addition, the first stuffing box unit 802, the second stuffing box unit 803 and the rotating shaft 17 are sealed by adopting stuffing 19, the matching surface between the first stuffing box unit 802 and the motor 801 is sealed by adopting sealing glue, and the matching surface between the second stuffing box unit 803 and the motor 801 is sealed by adopting sealing glue.

In the utility model, the inlet 601 of the liquid inlet pump head 6 is a centrifugal pump low-pressure water pipe joint, and the outlet 1203 of the liquid outlet pump head 12 is a centrifugal pump high-pressure water pipe joint; when the device works, the stuffing box module 8 acts, the rotating shaft 17 rotates, the rotating shaft 17 drives each impeller 7 to rotate, water enters the liquid inlet cavity 602 from the inlet 601 of the liquid inlet pump head 6, the water entering the liquid inlet cavity 602 enters the first accommodating cavity from the liquid inlet 603, the impeller 7 at the forefront end rotates, the water enters the centrifugal flow channel 702 from the flow channel inlet 701, high-pressure water is output from the centrifugal flow channel 703, the high-pressure water enters the second accommodating cavity at the forefront end, the corresponding impeller 7 in the second accommodating cavity throws out the high-pressure water, the high-pressure water enters the second accommodating cavity at the rear end, the impeller 7 in the second accommodating cavity at the rearmost end throws out the high-pressure water, the high-pressure water enters the third accommodating cavity, the water entering the third accommodating cavity is thrown out by the impeller 7 and enters the liquid outlet 1202 through the liquid outlet 1201; when the relay A1, the relay A2, the relay A3 and the relay A4 are fully opened, the U1 coil winding is sequentially connected with the U2 coil winding, the U3 coil winding and the U4 coil winding, the V1 coil winding is sequentially connected with the V2 coil winding, the V3 coil winding and the V4 coil winding, and the W1 coil winding is sequentially connected with the W2 coil winding, the W3 coil winding and the W4 coil winding; the relay A1, the relay A2 and the relay A3 are opened, when the relay A4 is closed, the U1 coil winding is sequentially connected with the U2 coil winding and the U3 coil winding, the V1 coil winding is sequentially connected with the V2 coil winding and the V3 coil winding, the W1 coil winding is sequentially connected with the W2 coil winding and the W3 coil winding, at the moment, the first motor, the second motor and the third motor work to output torque outwards, and the fourth motor does not work; when the relay A1 and the relay A2 are opened, and the relay A3 and the relay A4 are closed, the U1 coil winding is connected with the U2 coil winding, the V1 coil winding is connected with the V2 coil winding, and the W1 coil winding is connected with the W2 coil winding; when the relay A1 is opened and the relay A2, the relay A3 and the relay A4 are all closed, the output ends of the U1 coil winding, the V1 coil winding and the W1 coil winding directly skip the motor II, the motor III and the motor IV and then are grounded, only one pair of motors outputs torque, the rotor 801c of the motor I rotates, and the motor II, the motor III and the motor IV do not act; besides the above external torque output mode, there are other various permutation and combination, the switch of the relay A1, the relay A2, the relay A3 or the relay A4 can be controlled by the control unit according to the actual requirement, so as to realize the frequency conversion control of the utility model; in the utility model, through the structural arrangement of a plurality of motors 801 and circuit connection thereof, the frequency conversion control of the centrifugal pump can be realized by using the common motor 801; the motors 801 directly drive the rotating shaft 17 to rotate, so that loads acting on the rotating shaft 17 are uniform, working vibration and noise of the whole centrifugal pump are reduced, and the whole length of the centrifugal pump is shortened; the water path penetrates through the motor shell 801b of each motor 801, so that the motors 801 are rapidly cooled, and the service life of the motors 801 is prolonged; when the motor 801 does not work, other motors 801 can be used for replacing the motor 801 to be overhauled, the centrifugal pump cannot completely stop working due to damage of one motor 801, and the working reliability of the centrifugal pump is further improved; the water supply device is applied to water supply work.

While particular embodiments of the present invention have been described, it is to be understood that the present invention is not limited to the precise embodiments described above, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope of the appended claims. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims

1. A multistage centrifugal pump characterized by: the liquid inlet end bearing support is connected with a rotatable rotating shaft, the groups of stuffing modules are used for driving the rotating shaft to rotate, one side of the liquid inlet end bearing support in the left and right directions is fixedly connected with a liquid inlet pump head with a liquid inlet cavity, the liquid inlet pump head is connected with the rotating shaft, one end of the liquid inlet pump head facing downwards is provided with an inlet, one side of the liquid inlet pump head, which is far away from the liquid inlet end bearing support, is connected with one end of the foremost group of stuffing modules, the other end of one group of stuffing modules is connected with one end of the other group of stuffing modules, the rotating shaft of the outward end of the rearmost group of stuffing modules is connected with a liquid outlet cavity, and impellers are respectively connected with the rotating shafts between the liquid inlet pump head and the foremost group of stuffing modules, between the adjacent groups of stuffing modules and between the rearmost group of stuffing modules and the liquid outlet, the liquid inlet pump head is provided with a liquid inlet communicated with the liquid inlet cavity at one side opposite to the front group of stuffing box modules, a first accommodating cavity capable of accommodating liquid is formed between the front group of stuffing box modules and the liquid inlet pump head, a second accommodating cavity capable of accommodating liquid is formed between the adjacent groups of stuffing box modules, a third accommodating cavity capable of accommodating liquid is formed between the rear group of stuffing box modules and the liquid outlet pump head, a runner inlet is formed at one side of the impeller opposite to the liquid inlet pump head, a plurality of centrifugal runners are distributed on the impeller, a runner outlet is formed in the periphery of the impeller, one end of each centrifugal runner is communicated with the runner inlet, the other end of each centrifugal runner is communicated with the runner outlet, a liquid outlet is formed at one side opposite to the impeller, an upward end of the liquid outlet pump head is provided with an outlet, and the liquid outlet and the.

2. A multistage centrifugal pump according to claim 1, characterized in that: the stuffing box module comprises a stuffing box unit I, a motor and a stuffing box unit II, the motor comprises a motor shell and a rotor in the motor shell, one side of the motor shell is fixedly connected with the stuffing box unit I, the other side of the motor shell is fixedly connected with the stuffing box unit II, and the rotor is connected with the rotating shaft; a plurality of coaxially arranged liquid through holes I, liquid through holes II and liquid through holes III are respectively distributed on the stuffing box unit I, the motor shell and the stuffing box unit II; in the adjacent groups of stuffing boxes, a stuffing box unit II of one group of stuffing boxes is fixedly connected with a stuffing box unit I of the other group of stuffing boxes.

3. A multistage centrifugal pump according to claim 2, characterized in that: the stuffing box modules are provided with four groups, and when viewed from the direction from the foremost stuffing box module to the rearmost stuffing box module, motors in the four groups of stuffing box modules are respectively a motor I, a motor II, a motor III and a motor IV.

4. A multistage centrifugal pump according to claim 3, characterized in that: the motor comprises a first motor, a second motor, a third motor and a fourth motor, wherein the first motor, the second motor, the third motor and the fourth motor are respectively provided with a relay A1, a relay A2, a relay A3 and a relay A4, the control unit controls the switches of the relay A1, the relay A2, the relay A3 and the relay A4, the stator winding of the first motor comprises a coil winding U1, a coil winding V1 and a coil winding W1, the stator winding of the second motor comprises a coil winding U2, a coil winding V2 and a coil winding W2, the stator winding of the third motor comprises a coil winding U3, a coil winding V3 and a coil winding W3, the stator winding of the fourth motor comprises a coil winding U4, a coil winding V4 and a coil winding W4, the input ends of the coil winding U4, the coil winding V4 and the coil winding W4 are respectively connected with three-phase lines of a three-phase line of a three-phase terminal box, the output ends of the coil winding U4, the coil winding V, the input ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with a first terminal of the relay A1, the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are connected with a second terminal of the relay A1, when the relay A1 is in an open state, the common end of the relay A1 and the first terminal of the relay A1 are electrified, and the second terminal is not electrified; when the relay A1 is in a closed state, the common terminal of the relay A1 and the second terminal of the relay A1 are electrified, and the first terminal is not electrified; the output ends of the coil winding U2, the coil winding V2 and the coil winding W2 are also connected with the common end of the relay A2; the input ends of the coil winding U3, the coil winding V3 and the coil winding W3 are connected with a first terminal of the relay A2, the output ends of the coil winding U3, the coil winding V3 and the coil winding W3 are connected with a second terminal of the relay A2, when the relay A2 is in an open state, the common end of the relay A2 and the first terminal of the relay A2 are electrified, and the second terminal is not electrified; when the relay A2 is in a closed state, the common terminal of the relay A2 and the second terminal of the relay A2 are electrified, and the first terminal is not electrified; the output ends of the coil winding U3, the coil winding V3 and the coil winding W3 are also connected with the common end of the relay A3; the input ends of the coil winding U4, the coil winding V4 and the coil winding W4 are connected with a first terminal of the relay A3, the output ends of the coil winding U4, the coil winding V4 and the coil winding W4 are connected with a second terminal of the relay A3, when the relay A3 is in an open state, the common end of the relay A3 and the first terminal of the relay A3 are electrified, and the second terminal is not electrified; when the relay A3 is in a closed state, the common terminal of the relay A3 and the second terminal of the relay A3 are electrified, and the first terminal is not electrified; the output terminals of the coil winding U4, the coil winding V4, and the coil winding W4 are also connected to a common terminal of the relay a4, and the first terminal and the second terminal of the relay a4 are grounded, respectively.

5. A multistage centrifugal pump according to claim 2, characterized in that: one side of the first stuffing box unit and one side of the second stuffing box unit, which are arranged relative to the motor, are provided with connecting steps, the stuffing box unit is pressed in the motor shell through the connecting steps, the second stuffing box unit is pressed in the motor shell through the connecting steps, and the connecting steps are in interference fit with the motor shell.

6. A multistage centrifugal pump according to claim 1, characterized in that: one side fixedly connected with feed liquor stuffing box unit of feed liquor end bearing support on the left and right sides, feed liquor stuffing box unit keep away from feed liquor end bearing support place one side and feed liquor pump head fixed connection.

7. A multistage centrifugal pump according to any one of claims 1 to 6, characterized in that: one end of the liquid outlet pump head, which is far away from the liquid outlet impeller, is fixedly connected with a liquid outlet stuffing box unit, and one end of the liquid outlet stuffing box unit, which is far away from the liquid outlet pump head, is fixedly connected with a liquid outlet bearing support.

8. A multistage centrifugal pump according to claim 7, characterized in that: the liquid inlet end bearing support is fixedly connected with a liquid inlet bearing end cover on the other side in the left-right direction, the liquid outlet end bearing support is far away from one end where the liquid outlet stuffing box unit is located and is fixedly connected with a liquid outlet bearing end cover, one end of the rotating shaft is rotatably connected onto the liquid inlet end bearing support through the liquid inlet bearing, and the other end of the rotating shaft is rotatably connected onto the liquid outlet end bearing support through the liquid outlet bearing.