Shield motor capable of monitoring rotating speed of rotor in real time and real-time monitoring method

Abstract

The invention discloses a shield motor capable of monitoring the rotating speed of a rotor in real time and a real-time monitoring method, and relates to the field of shield motor rotating speed monitoring. A measuring seat is assembled on the motor stator, a plurality of coils are mounted on the measuring seat, and the motor rotor is in mechanical transmission connection with a permanent magnet; all the coils are located in a magnetic field of the permanent magnet, and the installation positions of the coils relative to the permanent magnet meet the requirement that the magnetic flux of the coils can be changed along with rotating motion of the permanent magnet. The coils are connected in series, and the coils at the head end and the tail end are connected to the processor; a pressure-bearing sleeve is fixedly and hermetically assembled on the motor stator; and the permanent magnet and the structure in mechanical transmission connection with the motor rotor are positioned in the pressure-bearing sleeve. The method can accurately monitor the rotating speed of the shield motor rotor in real time, discover abnormal rotating speed of the shield motor in time, and prevent further deterioration of accidents.

Description

Technical Field

[0001] The invention relates to the field of canned motor speed monitoring, in particular to a canned motor capable of real-time monitoring of rotor speed and a real-time monitoring method. Background Art

[0002] The canned motor is a motor used to transport highly toxic, corrosive, radioactive, flammable, explosive, precious liquids and liquids that will cause serious harm if leaked. The canned motor is directly connected to the pump impeller through the motor shaft to form a canned pump. The canned pump is a sealless pump. The pump and the drive motor are sealed in a pressure vessel filled with the pumped medium. This pressure vessel has only static seals and eliminates the rotating seal device of the centrifugal pump, so it can be completely leak-free. For a long time, due to the small gap between the stator and rotor and the large loss of the shielding sleeve, the shielding sleeve of the canned motor is prone to bulging, causing the rotor to get stuck, causing serious accidents in which the motor cannot rotate.

[0003] At present, there are three main ways to detect the motor speed: excitation coil speed measurement, photoelectric digital speed measurement, and speed measurement generator speed measurement; the principle of the excitation coil speed measurement is to set two or more excitation coils on the shielded motor, input electrical signals to a set of excitation coils A on the shielded motor in the non-working state, detect the output signal of another set of excitation coils B on the shielded motor, extract the signal from the output signal, and then convert it into the speed of the rotor forced to rotate; its principle and structure cannot be applied to the speed measurement of the shielded motor in high-speed rotation. The principle of photoelectric digital speed measurement is a method of measuring the motor speed by converting the optical signal into an electrical signal related to the speed through a speed sensor. The speed sensor mainly includes photoelectric encoders or gratings, which can generate pulsed electrical signals related to the speed, and measure the speed by measuring the number of pulses proportional to the speed in the standard unit time, or by measuring the time required to generate an electrical pulse signal; its principle and structure cannot be applied to the high-voltage environment and various corrosive media environments of the shielded motor, and the application environment is very limited. The principle of speed measurement by tachometer generator is to use the principle that the output voltage of DC generator is proportional to the speed. A small DC generator is installed on the shaft of the motor to be measured. According to the voltage output by the generator, the speed of the motor to be measured is briefly obtained. This principle and structure cannot be applied to high-temperature and high-pressure shielded motors with compact structure and sealed shaft inside. Other speed measuring instruments based on the principle of speed measurement by leakage magnetic speed measurement and vibration speed measurement cannot be applied to the measurement of the rotor speed of shielded motors due to their structural limitations or the limitations of the use environment.

[0004] In summary, due to the complete enclosure of the canned motor (rotating parts cannot be observed from the outside), the speed of the canned motor rotor cannot be detected by normal motor speed measurement methods, which eventually leads to further deterioration of the canned motor failure. Therefore, a technical solution that can monitor the speed of the canned motor rotor in real time is needed in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a shielded motor and a real-time monitoring method capable of monitoring the rotor speed in real time in response to the above-mentioned problems, so as to monitor the rotor speed of the shielded motor in real time and accurately, promptly detect abnormal shielded motor speed, and prevent the accident from further deteriorating.

[0006] The technical solution adopted by the present invention is as follows: a shielded motor capable of real-time monitoring of rotor speed, comprising a motor body, the motor body having a motor rotor and a motor stator, the motor stator being fixed, and the motor rotor rotating relative to the motor stator; a measuring seat being directly or indirectly mounted on the motor stator, a plurality of coils being mounted on the measuring seat, the motor rotor being mechanically connected to a permanent magnet, and the permanent magnet being able to obtain rotational power from the motor rotor; all coils being located in the magnetic field of the permanent magnet, and the permanent magnet rotating about the perpendicular bisector of its own south pole-north pole line as the axis, and the plane where the coil 4 is located being perpendicular to the perpendicular bisector; a plurality of coils being connected in series, and the coils at the head end and the end end being connected to a processor; a pressure sleeve being fixedly and sealedly mounted on the motor stator, and the permanent magnet and its structure mechanically connected to the motor rotor being located in the pressure sleeve.

[0007] Furthermore, the permanent magnet is fixed on a measuring rod, and the measuring rod is connected to the motor rotor via a mechanical transmission connection structure.

[0008] Furthermore, a countersunk hole is arranged on the top of the measuring rod, the permanent magnet is assembled in the countersunk hole, and a cover is sealed and fixedly connected at the opening of the countersunk hole.

[0009] Furthermore, the geometric shape and size of the countersunk hole match the permanent magnet.

[0010] Furthermore, the measuring rod serves as a structure of mechanical transmission connection and is coaxially fixedly connected to the motor rotor.

[0011] Furthermore, the measuring seat has an installation cavity, and the coil is fixed in the installation cavity; the pressure sleeve is sleeved on the measuring rod and passes through the installation cavity, so that the permanent magnet is located in the installation cavity.

[0012] Furthermore, the pressure sleeve is made of non-magnetic material.

[0013] Furthermore, the coil is connected to the processor via a frequency transmitter.

[0014] A method for real-time monitoring of the rotation speed of a canned motor, using the canned motor capable of real-time monitoring of the rotor rotation speed, comprises the following steps: S1: The motor rotor rotates, and the permanent magnet rotates synchronously; S2: The permanent magnet rotates, the magnetic flux of the coil changes, and a periodic induced electromotive force is generated; S3: The processor obtains the frequency of the induced electromotive force; S4: Obtain the rotation speed of the motor rotor according to the frequency of the induced electromotive force.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention can realize passive measurement of the rotation speed of the shielded motor, that is, the rotation speed of the shielded motor in operation can be acquired in real time without the need for an external power supply to power the measuring part, and only the processor and / or the frequency transmitter need to be supplied with power; 2. The present invention changes the magnetic flux of the coil by making the permanent magnet rotate with the rotor, so that the coil generates an induced electromotive force, and then determines the rotation speed of the rotor according to the frequency of the induced electromotive force; 3. The present invention forms a pressure boundary by setting a pressure sleeve to isolate the internal environment of the shielded motor from the external environment, so that the permanent magnet and the coil can be used to monitor the rotation speed of the motor rotor of the shielded motor without being affected by high pressure, corrosion and other environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 It is a structural schematic diagram of the present invention; Figure 2 The frequency diagram for different speed output; Markings in the figure: 1-measuring seat; 11-installation cavity; 2-permanent magnet; 3-measuring rod; 4-coil; 5-cover; 6-pressure sleeve; 7-motor stator. DETAILED DESCRIPTION

[0017] In the description of the present invention, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0018] In addition, if the terms "horizontal" or "vertical" appear in the description of the present invention, it does not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0019] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly stipulated and limited, the terms "set", "installed", "connected" and "connected" should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0020] Example 1 like Figure 1-Figure 2 As shown, a shielded motor capable of real-time monitoring of rotor speed includes a motor body, wherein the motor body has a motor rotor and a motor stator 7, the motor stator 7 is fixed, and the motor rotor rotates relative to the motor stator 7. The assembly relationship between the motor rotor and the motor stator 7 is known to those skilled in the art and will not be elaborated in this specification.

[0021] In this embodiment, the motor stator 7 is directly or indirectly equipped with a measuring seat 1, that is, it can be directly bolted to the motor stator 7; the measuring seat 1 can also be installed on a base, and the base is bolted to the motor stator 7, preferably installed on the end of the motor body away from the pump body to reduce the influence of the pump body on the measurement; the motor rotor is mechanically connected with a permanent magnet 2, and the permanent magnet 2 can obtain rotational power from the motor rotor. Specifically, the permanent magnet 2 can obtain rotational power from the motor rotor through mechanical transmission methods such as gears, coaxial, and chains. However, in the case where there is a transmission ratio, the transmission ratio should be considered when finally determining the motor speed; that is, the actual monitored speed is the speed of the permanent magnet 2, and the transmission ratio needs to be converted when determining the motor speed. The conversion method is known to those skilled in the art and will not be explained in detail in this specification.

[0022] In this embodiment, how to measure the rotational speed of the permanent magnet 2, so as to obtain the rotational speed of the shielded motor rotor; specifically, at least one coil 4 can be arranged on the measuring seat 1, all coils 4 are located in the magnetic field of the permanent magnet 2, and the installation position of the coil 4 relative to the permanent magnet 2 satisfies "as the permanent magnet 2 rotates, the magnetic flux of the coil 4 will change", that is, if the permanent magnet 2 rotates with the perpendicular bisector of its own south pole-north pole line as the axis, that is, the plane where the coil 4 is located and the perpendicular bisector present a certain angle, and the angle is preferably 90°, so that the magnetic flux change of the coil 4 is maximized, thereby maximizing the induced electromotive force of the coil 4; the coil 4 is connected to the processor, and the induced electromotive force of the coil 4 is obtained by the processor and the data of the induced electromotive force, such as peak value, period, frequency, etc., are processed. In this embodiment, the rotational speed of the permanent magnet 2 can be obtained according to the frequency of the induced electromotive force, so as to obtain the rotational speed of the shielded motor rotor.

[0023] In this embodiment, multiple coils 4 are connected in series, and the coils 4 at the head end and the tail end are connected to the processor, so that the induced electromotive force generated by each coil 4 is superimposed, thereby increasing the effective signal and improving the stability of signal acquisition.

[0024] It should be noted that when each coil 4 is connected in series using a wire, the positive and negative directions of the induced electromotive force generated by the coil 4 need to be considered, which is known to those skilled in the art and will not be described in detail in this specification.

[0025] In this embodiment, the motor stator is also fixedly and sealedly equipped with a pressure sleeve 6, that is, there is relative rotation between the pressure sleeve 6 and the permanent magnet 2, which will not affect the measured data; the permanent magnet 2 and the structure of the mechanical transmission connection with the motor rotor are both located in the pressure sleeve 6, which actually isolates the internal environment of the shielded motor from the external environment, that is, the medium is located in the pressure sleeve 6, so that the pressure sleeve 6 forms a pressure boundary to prevent the medium inside the shielded motor from leaking into the external environment.

[0026] Furthermore, the pressure sleeve 6 is made of non-magnetic conductive material to prevent the formation of magnetic shielding and ensure the accuracy of the measured data.

[0027] To sum up, the scheme disclosed in this embodiment can realize passive measurement of the rotational speed of the shielded motor, that is, the rotational speed of the shielded motor in operation can be acquired in real time without the need for an external power supply to power the measuring part, and only the processor and / or the frequency transmitter need to be supplied with power; the permanent magnet 2 rotates with the rotor, so that the magnetic flux of the coil 4 changes, so that the coil 4 generates an induced electromotive force, and then the rotational speed of the rotor is determined according to the frequency of the induced electromotive force; a pressure boundary is formed by setting a pressure sleeve 6 to isolate the internal environment of the shielded motor from the external environment, so that the permanent magnet 2 and the coil 4 can be used to monitor the rotational speed of the motor rotor of the shielded motor without being affected by high pressure, corrosion and other environments.

[0028] Example 2 Based on Example 1, a specific implementation method that can be implemented is further proposed.

[0029] A feasible implementation method is that the permanent magnet 2 is fixed on the measuring rod 3, and the measuring rod 3 can be fixedly connected to the motor rotor coaxially, that is, the permanent magnet 2 is connected to the motor rotor through the measuring rod 3, which facilitates the installation of the permanent magnet 2 and can also achieve synchronization of the rotation speed of the permanent magnet 2 with the rotation speed of the motor rotor without excessive conversion procedures.

[0030] Furthermore, the bottom of the measuring rod 3 is used to be fixedly connected coaxially with the motor rotor, and a countersunk hole is provided on the top of the measuring rod 3. The permanent magnet 2 is assembled in the countersunk hole, and a cover 5 is sealed and fixedly connected at the opening of the countersunk hole, which effectively avoids contamination or corrosion of the permanent magnet 2 by the medium in the shielding motor.

[0031] A feasible implementation method is that the size of the countersunk hole matches the size of the permanent magnet 2, and the permanent magnet 2 is fixed in the countersunk hole with the constraint of the cover 5, so that the permanent magnet 2 can be completely synchronized when rotating with the motor rotor, and there will be no delay in starting rotation or stopping rotation due to the inertia of the permanent magnet 2 itself.

[0032] A feasible implementation method, regarding the installation of the coil 4, can be to open an installation cavity 11 on the measuring seat 1, the coil 4 is fixed in the installation cavity 11, the measuring rod 3 passes through the installation cavity 11, and the permanent magnet 2 is located in the installation cavity 11; the coil 4 is arranged in a circumferential array around the rotation axis of the measuring rod 3.

[0033] In a feasible implementation mode, the coil 4 is connected to the processor through a frequency transmitter to transmit the frequency signal of the induced electromotive force, and the processor receives the frequency signal and determines the speed of the motor rotor according to the frequency signal. In this embodiment, the frequency transmitter can be a transmitter of model ASGFC-H1D, and the processor can be a microprocessor.

[0034] It should be noted that the frequency transmitter and the microprocessor can be connected to an external power supply to ensure continuous energy supply and maintain the stability of frequency signal transmission and processing.

[0035] Example 3 A method for real-time monitoring of the rotation speed of a canned motor, using the canned motor capable of real-time monitoring of the rotor rotation speed described in any one of the embodiments 1-2, comprises the following steps: S1: The motor rotor rotates, and the permanent magnet 2 rotates synchronously; S2: The permanent magnet 2 rotates, the magnetic flux of the coil 4 changes, and a periodic induced electromotive force is generated; S3: The processor obtains the frequency of the induced electromotive force; S4: Obtain the rotation speed of the motor rotor according to the frequency of the induced electromotive force.

[0036] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A canned motor capable of real-time monitoring of rotor speed, comprising a motor body, the motor body having a motor rotor and a motor stator (7), the motor stator (7) being fixed, and the motor rotor rotating relative to the motor stator (7); characterized in that: A measuring seat (1) is directly or indirectly mounted on a motor stator (7), a plurality of coils (4) are mounted on the measuring seat (1), the motor rotor is mechanically connected to a permanent magnet (2), the permanent magnet (2) can obtain rotational power from the motor rotor; all coils (4) are located in the magnetic field of the permanent magnet (2), and the permanent magnet (2) rotates about the midpoint of the line connecting its own south pole and north pole as an axis, and the plane where the coils 4 are located is perpendicular to the midpoint; the plurality of coils (4) are connected in series, and the coils (4) at the head end and the end end are connected to a processor; a pressure sleeve (6) is also fixedly and sealedly mounted on the motor stator (7), and the permanent magnet (2) and the structure mechanically connected to the motor rotor are both located in the pressure sleeve (6).

2. The shielded motor according to claim 1, characterized in that: The permanent magnet (2) is fixed on a measuring rod (3), and the measuring rod (3) is connected to the motor rotor via a mechanical transmission connection structure.

3. The shielded motor according to claim 2, characterized in that: The top of the measuring rod (3) is provided with a countersunk hole, the permanent magnet (2) is mounted in the countersunk hole, and a cover (5) is sealed and fixedly connected at the opening of the countersunk hole.

4. The shielded motor according to claim 3, characterized in that: The geometry and size of the countersunk hole are matched to the permanent magnet.

5. The shielded motor according to claim 2, characterized in that: The measuring rod (3) serves as a mechanical transmission connection structure and is fixedly connected coaxially with the motor rotor.

6. The shielded motor according to claim 5, characterized in that: The measuring seat (1) has a mounting cavity (11), and the coil (4) is fixed in the mounting cavity (11); the pressure sleeve (6) is sleeved on the measuring rod (3) and passes through the mounting cavity (11), so that the permanent magnet (2) is located in the mounting cavity (11).

7. The shielded motor according to claim 6, characterized in that: The pressure-bearing sleeve (6) is made of non-magnetic material.

8. The shielded motor according to claim 1, characterized in that: The coil (4) is connected to the processor via a frequency transmitter.

9. A method for real-time monitoring of the rotation speed of a canned motor, using the canned motor capable of real-time monitoring of the rotor rotation speed according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: The motor rotor rotates, bringing the permanent magnet (2) with it to rotate synchronously; S2: The permanent magnet (2) rotates, the magnetic flux of the coil (4) changes, and a periodic induced electromotive force is generated; S3: The processor obtains the frequency of the induced electromotive force; S4: Obtain the rotation speed of the motor rotor according to the frequency of the induced electromotive force.

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