阅读说明：本技术 电磁控制轴向力平衡的多级离心泵 (Electromagnetic control axial force balanced multistage centrifugal pump ) 是由 于文超 王家斌 林海 张本营 邹存海 邹英杰 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种电磁控制轴向力平衡的多级离心泵,包括泵体、泵轴、平衡盘、叶轮、导叶、进水段、出水段、高压侧轴承部件、高压侧机械密封、低压侧轴承部件、低压侧机械密封,其特征在于还包括控制装置、电磁腔,电磁铁、永磁铁、位移传感器、压力传感器,通过所述位移传感器实时监测泵轴旋转过程中的轴向移动间隙,并上传至控制装置,通过所述压力传感器实时监测出水压力大小,并将压力信息上传至控制装置,控制装置通过控制电磁铁的电流来平衡多级离心泵轴向力的波动,本发明解决了多级离心泵在运行过程中和开、关机的时候轴向力失衡的技术问题,避免了多级离心泵的平衡盘磨损或烧毁,使得运行的稳定性显著提高,延长了使用寿命。(The invention discloses a multistage centrifugal pump with balanced electromagnetic control axial force, which comprises a pump body, a pump shaft, a balance disc, an impeller, a guide vane, a water inlet section, a water outlet section, a high-pressure side bearing component, a high-pressure side mechanical seal, a low-pressure side bearing component and a low-pressure side mechanical seal, and is characterized by also comprising a control device, an electromagnetic cavity, an electromagnet, a permanent magnet, a displacement sensor and a pressure sensor, wherein the axial movement gap in the rotation process of the pump shaft is monitored in real time through the displacement sensor and is uploaded to the control device, the water outlet pressure is monitored in real time through the pressure sensor, pressure information is uploaded to the control device, and the control device balances the fluctuation of the axial force of the multistage centrifugal pump by controlling the current of the electromagnet. The stability of operation is obviously improved, and the service life is prolonged.)

1. A multistage centrifugal pump with balanced electromagnetic control axial force comprises a pump body, a pump shaft, a balance disc, an impeller, a guide vane, a water inlet section, a water outlet section, a high-pressure side bearing component, a high-pressure side mechanical seal, a low-pressure side bearing component and a low-pressure side mechanical seal, and is characterized by further comprising a control device, an electromagnetic cavity, an electromagnet, a permanent magnet, a displacement sensor (15-1), a displacement sensor (15-2) and a pressure sensor, wherein the pump shaft extends outwards into the electromagnetic cavity along the high-pressure side bearing component, the pump shaft in the electromagnetic cavity is fixedly provided with the permanent magnet, the inner wall of the electromagnetic cavity at the periphery of the permanent magnet is fixedly provided with the electromagnet, the electromagnet is electrically connected with the control device, the displacement sensor (15-1) is arranged on the dynamic balance disc of the balance disc, and the displacement sensor (15-2) is, the displacement sensor (15-1) corresponds to the displacement sensor (15-2), the displacement sensor (15-1) and the displacement sensor (15-2) are respectively and electrically connected with the control device, the pressure sensor is installed on the side wall of the water outlet section, and the pressure sensor is electrically connected with the control device.

2. The multistage centrifugal pump with balanced electromagnetic control axial force as claimed in claim 1, wherein the control device is a PLC control device, and the PLC control device is embedded with a program step of monitoring pressure and displacement in real time during operation, a program step of controlling the magnitude of current of the electromagnet, and a program step of maintaining a minimum safe distance when starting up and shutting down.

Technical Field

The invention relates to the technical field of fluid machinery, in particular to a multistage centrifugal pump with balanced electromagnetic control axial force.

Background

At present, the existing axial force balance mechanism of the multi-stage centrifugal pump shaft 2 is mainly a balance disc 3. This balancing device has two sealing gaps, see fig. 2, one of which is a radial gap b1 between the hub (or the sleeve) and the pump body 1; the other is that an axial clearance b2 is arranged between the end surface of the balance disc 3 and the pump body 1. The balance chamber behind the balance disc 3 is communicated with the inlet of the pump body 1 by a communicating pipe. The pressure of the liquid before the radial gap is the pressure P3 under the back shroud of the last stage impeller 4, which is reduced to P4 through the radial gap b1 and to P5 through the axial gap, while the pressure of the liquid at the lower back of the balance disk 3 is P6, which is approximately different from the pump suction pressure by a communicating pipe loss. The pressure difference P4-P6 between the front and rear of the balance disc 3 generates a backward thrust on the balance disc 3, called balance force F1, F1, in the opposite direction to the axial force F of the liquid acting on the rotor, so as to balance the axial force. The two gaps in such a balancing device are each active and interconnected. If the axial force F on the rotor is greater than the balance force F1 on the balance disk 3, the rotor will move to the left, thus reducing the axial gap b2, increasing the clearance resistance and reducing the leakage. In this way the speed of the liquid flowing through the radial gap b1 is reduced and the losses in this gap are reduced, thereby increasing the pressure P4 in front of the balancing disk 3, the rotor constantly moving to the left. The balance force is increased and moved to a position where the balance force F1 is equal to the axial force F, thereby achieving a new balance. Similarly, when the axial force is less than the balance force, the rotor moves to the right, and the new balance can be achieved. However, the inertial force during the left-right movement of the rotor causes the axial gap b2 not to stay at the position where the axial force is balanced, thereby causing unbalance of the axial force, and if the balance is not established in time, the balance disc 3 is worn and burned out. Meanwhile, the multistage centrifugal pump of this type cannot establish balance due to loss of pressure in the processes of starting and stopping, and also causes abrasion and burnout of the balance disc 3.

In addition, for the working conditions of intermittent operation (such as the high-pressure hydraulic decoking pump in a petrochemical industry delayed coking device, starting for 1-2 times every day and operating for 2-4 hours every time), frequent starting and particle-containing media, the end faces of the balance disc 3 and the balance sleeve can be abraded once when the pump set is started or stopped once. When the abrasion loss of the balance disc 3 exceeds the retained displacement between the balance disc 3 and the centrifugal pump body 1 to the suction end, the wear-resisting ring (rotating part) of the front cover plate of the centrifugal pump impeller 4 and the wear-resisting ring (static part) of the centrifugal pump body 1 are abraded, and the impeller 4 in the centrifugal pump rotor part is meshed with the wear-resisting ring in serious conditions, so that the safe and stable operation of the pump set is threatened. In addition, with the balance disk 3 configuration, the medium heats up slightly in the pump, especially at low flow rates, (resulting in a lower pump efficiency. in this case, the balance leakage water is reduced in pressure through a small gap, which can vaporize and create pressure fluctuations.

Disclosure of Invention

The invention aims to solve the defects of the prior art and provides the electromagnetic control axial force balance multistage centrifugal pump which is novel in structure, high in automation degree, high in operation stability, long in service life and high in working efficiency.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a multistage centrifugal pump with balanced electromagnetic control axial force comprises a pump body 1, a pump shaft 2, a balance disc 3, an impeller 4, a guide vane 5, a water inlet section 6, a water outlet section 7, a high-pressure side bearing component 8, a high-pressure side mechanical seal 9, a low-pressure side bearing component 10 and a low-pressure side mechanical seal 11, and is characterized by further comprising a control device, an electromagnetic cavity 12, an electromagnet 13, a permanent magnet 14, a displacement sensor 15-1, a displacement sensor 15-2 and a pressure sensor 16, wherein the pump shaft 2 extends outwards into the electromagnetic cavity 12 along the high-pressure side bearing component 8, the permanent magnet 14 is fixed on the pump shaft 2 in the electromagnetic cavity 12, the electromagnet 13 is fixed on the inner wall of the electromagnetic cavity 12 at the periphery of the permanent magnet 14, the electromagnet 13 is electrically connected with the control device, the displacement sensor 15-1 is installed on a dynamic balance disc of the balance disc 3, the displacement sensor 15-2 is installed on a static balance disc, the displacement sensor 15-1 corresponds to the displacement sensor 15-2, the displacement sensor 15-1 and the displacement sensor 15-2 are respectively and electrically connected with a control device, the pressure sensor 16 is installed on the side wall of the water outlet section 7, the pressure sensor 16 is electrically connected with the control device, the axial movement gap of the pump shaft 2 in the rotating process is monitored in real time through the displacement sensor 15-1 and the displacement sensor 15-2 and is uploaded to the control device, the water pressure is monitored in real time through the pressure sensor 16, the pressure information is uploaded to the control device, and the control device balances the fluctuation of the axial force of the multi-stage centrifugal pump shaft 2 by controlling the current of the electromagnet 13.

The control device adopts a PLC control device, and the PLC control device is embedded with a program step for monitoring pressure and displacement in real time in the running process, a program step for controlling the current of the electromagnet 13 and a program step for keeping the minimum safe distance when the device is started and shut down, so as to achieve the effect of automatically adjusting balance.

By adopting the structure, the invention solves the technical problem of axial force unbalance caused by pressure fluctuation in the operation process of the multistage centrifugal pump, simultaneously solves the technical problem of axial force unbalance caused by pressure loss when the multistage centrifugal pump is started or shut down, avoids abrasion or burning of a balance disc of the multistage centrifugal pump, obviously improves the operation stability and prolongs the service life.

Drawings

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

Fig. 2 is a control schematic block diagram of the present invention.

Fig. 3 is a schematic diagram of axial force balancing in the prior art.

Reference numerals: the pump comprises a pump body 1, a pump shaft 2, a balance disc 3, an impeller 4, a guide vane 5, a water inlet section 6, a water outlet section 7, a high-pressure side bearing component 8, a high-pressure side mechanical seal 9, a low-pressure side bearing component 10, a low-pressure side mechanical seal 11, an electromagnetic cavity 12, an electromagnet 13, a permanent magnet 14, a displacement sensor 15, a pressure sensor 16, a pump motor 17 and a PLC (programmable logic controller) control device 18.

Detailed Description

The invention is described below with reference to the accompanying drawings and examples.

Embodiment, as shown in fig. 1, a multistage centrifugal pump with electromagnetically controlled axial force balance comprises a pump body 1, a pump shaft 2, a balance disk 3, an impeller 4, a guide vane 5, a water inlet section 6, a water outlet section 7, a high-pressure side bearing component 8, a high-pressure side mechanical seal 9, a low-pressure side bearing component 10, and a low-pressure side mechanical seal 11, wherein the pump body 1, the pump shaft 2, the balance disk 3, the impeller 4, the guide vane 5, the water inlet section 6, the water outlet section 7, the high-pressure side bearing component 8, the high-pressure side mechanical seal 9, the low-pressure side bearing component 10, and the low-pressure side mechanical seal 11 have the same structure and connection relationship as the prior art, which are not repeated, and are characterized by further comprising a control device, an electromagnetic cavity 12, an electromagnet 13, a permanent magnet 14, a displacement sensor 15-1, a displacement sensor 15-2, and a pressure sensor 16, wherein the pump shaft 2 extends outwards into the, a permanent magnet 14 is fixed on the pump shaft 2 in the electromagnetic cavity 12, an electromagnet 13 is fixed on the inner wall of the electromagnetic cavity 12 at the periphery of the permanent magnet 14, the electromagnet 13 is electrically connected with a control device, the displacement sensor 15-1 is installed on a dynamic balance disc of the balance disc 3, the displacement sensor 15-2 is installed on a static balance disc of the balance disc, the displacement sensor 15-1 corresponds to the displacement sensor 15-2, the dynamic balance disc is fixed on the pump shaft, the static balance disc is fixed on the pump body, the displacement sensor 15-1 and the displacement sensor 15-2 are respectively and electrically connected with the control device, the pressure sensor 16 is installed on the side wall of the water outlet section 7, the pressure sensor 16 is electrically connected with the control device, and the axial movement gap of the pump shaft 2 in the rotation process is monitored in real time through the displacement sensor 15-1 and the displacement sensor 15-2, the axial force unbalance detection device is characterized by comprising a pressure sensor 16, a control device, an electromagnet 13, a balance disc 3, a balance disc, a pressure sensor 16, a pressure sensor, a control device and a control device, wherein the pressure sensor 16 is used for monitoring the water outlet pressure in real time and transmitting pressure information to the control device, and the control device is used for controlling the current of the electromagnet 13 to balance the fluctuation of the axial force of the pump shaft 2 of the multistage centrifugal pump.

The control device adopts a PLC (programmable logic controller) 18, and a program step of monitoring pressure and displacement in real time in the running process, a program step of controlling the current of the electromagnet 13 and a program step of keeping the minimum safe distance when the device is started and shut down are embedded in the PLC so as to achieve the effect of automatically adjusting balance.

When the pump is started to operate, the PLC control device 18 firstly supplies power to the electromagnet 13, when the displacement sensor 15 receives a displacement signal S of the balance disc 3 on the pump shaft 2 and uploads the displacement signal S to the PLC control device, the PLC control device compares the received displacement signal S with the minimum safe axial distance b, and when a displacement value S monitored by the displacement sensor 15-1 and the displacement sensor 15-2 is larger than or equal to the minimum safe axial distance b, the PLC control device 18 directly instructs the pump motor 17 to supply power; if the displacement value S is smaller than the minimum safe axial distance b, the PLC control device 18 supplies power to the pump motor according to the current of the electromagnet 13 corresponding to the compared numerical value, so that the fluctuation of the axial force is balanced by the electromagnet 13 according to the corresponding current, and the pump shaft 2 is kept to operate within a standard range;

in the operation process, when the operation condition changes, the pressure sensor 16 uploads a pressure signal P5 of water in the water outlet section 7 to the PLC control device, the PLC control device 18 corresponds to a standard axial gap b2 set in the program step according to different uploaded pressure signals P5, the standard axial gap b2 ensures that the axial force under the pressure of the pressure signal P5 is balanced, meanwhile, the displacement sensor 15-1 and the displacement sensor 15-2 receive a displacement signal value S of the balance disc 3 on the pump shaft 2 and upload the displacement signal value S to the PLC control device 18, the PLC control device 18 compares the uploaded displacement signal value S with the standard axial gap b2, the current of the electromagnet 13 is controlled by the difference value of the displacement signal value S and the standard axial gap b2, so that the electromagnet 13 controls the permanent magnet 14 to generate the axial force by changing the magnetic force of the electromagnet 13 through the current, and ensures that the axial gap between the pump shaft 2 and the pump body 1 can quickly reach the set standard axial gap b2, the damage of the inertial force of the pump rotor to the axial force balance is effectively restrained, the abrasion and burning of the balance disc 3 are avoided, the service life is prolonged, and the working efficiency is obviously improved;

when the pump stops running, the PLC control device 18 firstly cuts off the power of the pump motor, the PLC control device 18 continuously supplies power to the electromagnet 13, the displacement signal value S monitored by the displacement sensor 15 is ensured to be larger than or equal to a set value, when the pressure value monitored by the pressure sensor 16 is 0, the pump shaft 2 is not rotated, the lift reaches 0, and the PLC system cuts off the power of the electromagnetic system again, namely the pump shaft 2 is kept in a standard range to stop running.

The minimum safe axial distance is 0.1mm, the standard axial clearance b2 is set to be 0.1mm-0.28mm, and the displacement signal value S is set to be 0.1mm-0.28 mm.

By adopting the structure, the invention effectively solves the technical problem that the axial force is transiently unbalanced due to the change of working conditions in the operation process of the multi-stage pump, so that the balance disc is abraded and burnt, also solves the technical problem that the axial force is unbalanced due to pressure loss when the multi-stage pump is started and shut down, avoids the abrasion and burning of the balance disc of the multi-stage pump, and has the advantages of novel structure, high stability, prolonged service life, capability of realizing rapid automatic balance of the axial force and the like.