CN113217634A - Magnetic liquid sealing starting system and starting method - Google Patents
Magnetic liquid sealing starting system and starting method Download PDFInfo
- Publication number
- CN113217634A CN113217634A CN202110411110.7A CN202110411110A CN113217634A CN 113217634 A CN113217634 A CN 113217634A CN 202110411110 A CN202110411110 A CN 202110411110A CN 113217634 A CN113217634 A CN 113217634A
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- Prior art keywords
- magnetic liquid
- motor
- rotating speed
- starting
- magnetic
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/40—Sealings between relatively-moving surfaces by means of fluid
- F16J15/43—Sealings between relatively-moving surfaces by means of fluid kept in sealing position by magnetic force
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/10—Arrangements for controlling torque ripple, e.g. providing reduced torque ripple
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Mechanical Engineering (AREA)
- Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
Abstract
The invention discloses a magnetic liquid seal starting system and a starting method, wherein the magnetic liquid seal starting system comprises a magnetic liquid seal assembly, a motor, a rotating speed sensor and a frequency converter, the motor is connected with the magnetic liquid seal assembly and used for starting the magnetic liquid seal assembly, the rotating speed sensor detects the rotating speed of the motor, and the frequency converter is connected with the motor so that when the motor reaches a preset rotating speed, the frequency converter is switched from a torque control mode to a rotating speed control mode. The magnetic liquid sealing starting system has the advantages of simple structure, convenience in use, stability in starting and the like.
Description
Technical Field
The invention mainly relates to the field of sealing starting systems and control thereof, in particular to a magnetic liquid sealing starting system and a starting method.
Background
The magnetic liquid seal has the advantages of low friction, zero leakage, long service life and the like, and is widely applied to important occasions such as military industry, aerospace, deep diving and the like.
In the related art, when the sealing element is connected with the motor to start, unstable vibration occurs inside the magnetic liquid sealing device, so that the magnetic liquid in a sealing gap of the magnetic liquid sealing device is lost, and the sealing capability of the magnetic liquid sealing device is reduced or even loses efficacy.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, the embodiment of the invention provides a magnetic liquid sealing starting system which is stable in starting, effectively avoids sudden change of torque and rotating speed in the starting process, and prevents magnetic liquid from flowing out of a sealing gap.
The embodiment of the invention provides a magnetic liquid seal starting method.
The magnetic liquid seal starting system according to the embodiment of the invention comprises: a magnetic liquid seal assembly; the motor is connected with the magnetic liquid sealing assembly and used for starting the magnetic liquid sealing assembly; a rotation speed sensor that detects a rotation speed of the motor; and the frequency converter is connected with each of the motor and the rotating speed sensor, so that when the motor reaches a preset rotating speed, the frequency converter is switched from a torque control mode to a rotating speed control mode.
According to the magnetic liquid seal starting system provided by the embodiment of the invention, the power of the motor is adjusted through the frequency converter, so that the sudden change of the moment and the rotating speed of the magnetic liquid seal assembly in the starting process is prevented, the magnetic liquid is prevented from flowing away from the seal gap, and the service life of the magnetic liquid seal assembly is prolonged.
In some embodiments, the magnetic liquid seal actuation system further comprises a rotational rheometer coupled to the magnetic liquid seal assembly for measuring changes in viscosity of the magnetic liquid over time under stress.
In some embodiments, the rotational rheometer is provided with a magnetic field module.
In some embodiments, the magnetic liquid seal actuation system further comprises a controller coupled to each of the motor, the frequency converter, and the rotational speed sensor.
According to the embodiment of the invention, the magnetic liquid seal starting method comprises the following steps: s1: measuring the change condition of the viscosity of the magnetic liquid along with time under the action of different constant stresses, and determining the driving torque; s2: starting a frequency converter to adjust the power of a motor, wherein the frequency converter starts the motor in a torque control mode, and the motor drives a rotating shaft of a magnetic liquid sealing assembly to rotate by the driving torque; s3: detecting the rotating speed of the motor in real time; s4: and when the rotating speed of the motor reaches a preset rotating speed, switching the frequency converter from the torque control mode to a rotating speed control mode so that the motor is smoothly transited to the working rotating speed from the preset rotating speed.
According to the magnetic liquid seal starting method provided by the embodiment of the invention, the frequency of the motor is adjusted through the conversion of the frequency converter between the torque control mode and the rotating speed control mode, the problem of rotating speed mutation in the starting process of the magnetic liquid seal assembly is effectively avoided, the running stability of the system is improved, and the stability of the magnetic liquid is ensured not to be damaged.
In some embodiments, a thixotropic agent is added to the magnetic liquid before step S1 is initiated.
In some embodiments, the thixotropic agent is a clay or polymeric material.
In some embodiments, in step S1, the change in viscosity of the magnetic liquid with time under different stresses is measured by a rotational rheometer.
In some embodiments, in step S1, a starting stress value is determined, the magnetic liquid flow is equivalent to a couette flow model under concentric cylinders, and the starting stress value is converted into the driving torque.
In some embodiments, in the step S3, the actual rotation speed of the motor is detected using a rotation speed sensor in the step S3.
Drawings
FIG. 1 is a schematic diagram of the components of the seal activation system of the present invention.
Fig. 2 is a flow chart schematic of the inventive seal activation control method.
Fig. 3 is a schematic diagram of the seal activation control method of the present invention.
Reference numerals:
a frequency converter 1; a motor 2; a rotation speed sensor 3; a magnetic liquid seal assembly 4; and a controller 5.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
A magnetic liquid seal actuation system according to an embodiment of the present invention is described below with reference to fig. 1.
As shown in fig. 1, the magnetic liquid seal starting system according to the embodiment of the present invention includes a magnetic liquid seal assembly 4, a motor 2, a rotation speed sensor 3, and a frequency converter 1.
The motor 2 is connected with the magnetic liquid seal assembly 4 and used for starting the magnetic liquid seal assembly 4. Specifically, the motor 2 is connected with the rotating shaft of the magnetic liquid seal assembly 4, and the motor 2 drives the rotating shaft of the magnetic liquid seal assembly 4 to rotate.
The rotation speed sensor 3 detects the rotation speed of the motor 2. Thereby, the rotation speed of the motor 2 is detected in real time by the rotation speed sensor 3.
The frequency converter 1 is connected to each of the motor 2 and the rotation speed sensor 3, so that the frequency converter 1 is switched from the torque control mode to the rotation speed control mode when the motor 2 reaches a preset rotation speed.
The inventor finds out through research that: when the motor 2 is started, the viscosity of the magnetic liquid is rapidly reduced due to the decomposition of the internal structure of the magnetic liquid, and due to the fact that the internal acceleration of the magnetic liquid is large in the process, shear flows in different space directions usually exist under the action of pressure, so that the magnetic liquid in a sealing gap is lost, and the sealing capability is reduced or even loses efficacy.
According to the magnetic liquid seal starting system provided by the embodiment of the invention, the frequency converter 1 is connected with each of the motor 2 and the rotating speed sensor 3, so that when the motor 2 reaches a preset rotating speed, the frequency converter 1 is switched from a torque control mode to a rotating speed control mode. From this, be used for adjusting the power of motor 2 through converter 1, open motor 2 under converter 1 is the torque control mode, when the rotational speed of motor 2 reachs and predetermines the rotational speed, switch over converter 1 to the rotational speed control mode by the torque control mode, thereby prevent that magnetic fluid seal assembly 4 is when the start-up, the inside acceleration of magnetic fluid is too big, prevent that magnetic fluid from running off in the sealed clearance, guaranteed magnetic fluid seal assembly 4's sealing performance, magnetic fluid seal assembly 4's life has been prolonged.
In some embodiments, the magnetic liquid seal activation system further comprises a rotational rheometer coupled to the magnetic liquid seal assembly 4. Therefore, the condition that the viscosity of the magnetic liquid changes along with time under the action of different stresses can be measured through the rotary rheometer, and therefore the appropriate starting stress is selected through the rotary rheometer.
In some embodiments, a rotational rheometer is provided with a magnetic field module. Therefore, the measurement result of the rotating rheometer on the magnetic liquid is more accurate, and the operation of a subsequent starting method is ensured.
In some embodiments, the magnetic liquid seal actuation system further comprises a controller 5, the controller 5 being connected to each of the motor 2, the frequency converter 1 and the rotation speed sensor 3. Therefore, the rotating speed sensor 3 detects the rotating speed of the motor 2, the signal detected by the rotating speed sensor 3 is uploaded to the controller 5, and the working mode of the frequency converter 1 is adjusted through the controller 5, so that the frequency of the motor 2 is adjusted.
It can be understood that the controller 5 adopts a programmable logic controller, the programmable logic controller has the advantages of small volume, convenient maintenance, low energy consumption, strong interference capability and the like, and the motor 2 adopts three alternating current motors, and the three alternating current motors have the advantages of simple structure, low price, convenient use and maintenance and the like.
As shown in fig. 2 to 3, the embodiment of the present invention further provides a magnetic liquid seal startup method, including the following steps:
s1: and measuring the change condition of the viscosity of the magnetic liquid along with the time under the action of different constant stresses, and determining the driving torque. Therefore, the control parameters of the motor 2 are determined according to the rheological characteristics of the magnetic liquid, and the starting time and the rotating speed change process of the motor 2 can be accurately controlled and predicted.
S2: the frequency converter 1 is started to adjust the power of the motor 2, the frequency converter 1 starts the motor 2 in a torque control mode, and the motor 2 drives a rotating shaft of the magnetic liquid sealing component 4 to rotate by driving torque.
S3: the rotation speed of the motor 2 is detected in real time.
S4: when the rotating speed of the motor 2 reaches the preset rotating speed, the frequency converter 1 is switched from the torque control mode to the rotating speed control mode, so that the motor 2 is smoothly transited to the working rotating speed from the preset rotating speed. Specifically, when the actual rotational speed of the motor 2 reaches the preset rotational speed, the controller 5 switches the frequency converter 1 from the torque control mode to the rotational speed control mode.
It can be understood that the preset rotating speed and the working rotating speed are both set by an experimenter according to actual needs, and the preset rotating speed is close to the working rotating speed.
According to the magnetic liquid seal starting method provided by the embodiment of the invention, the power of the motor 2 is adjusted by starting the frequency converter 1, the frequency converter 1 is in a torque control mode, the motor 2 is started, and the motor 2 applies a starting torque to the shaft of the magnetic liquid seal assembly 4, so that the magnetic liquid seal assembly 4 is started stably, the sudden change of the torque and the rotating speed in the starting process of the magnetic liquid seal assembly 4 is avoided, the magnetic liquid is prevented from flowing away from a seal gap, and the service life of the magnetic liquid seal assembly 4 is prolonged.
According to the magnetic liquid sealing starting method provided by the embodiment of the invention, when the rotating speed of the motor 2 reaches the preset rotating speed, the frequency converter 1 is switched from the torque control mode to the rotating speed control mode, so that the motor 2 is smoothly transited to the working rotating speed from the preset rotating speed. From this, switch over to the mode that the rotational speed control mode combined together through the torque control mode, guarantee that motor 2 reaches operating speed fast under the condition of steady start, further reduced the loss of magnetic fluid, prolonged the life of magnetic fluid seal assembly 4.
In some embodiments, a thixotropic agent is added to the magnetic liquid before step S1 is initiated. Therefore, the thixotropy of the magnetic liquid is improved, the viscosity of the magnetic liquid is stably changed along with time under fixed stress, and the change condition of the viscosity of the magnetic liquid along with time under the action of different constant stresses is conveniently measured.
It can be understood that: thixotropy refers to the property of a body that becomes less thick when sheared, increases thick when shear is stopped, or becomes more thick when sheared, and becomes less thick when shear is stopped.
In some embodiments, the thixotropic agent is a clay or polymeric material. Therefore, thixotropic agents such as clay and high polymer are added into the magnetic liquid, so that the magnetic liquid has strong thixotropy, and the viscosity of the magnetic liquid is stably changed along with time under fixed stress.
In some embodiments, in step S1, the change in viscosity of the magnetic liquid with time under different stresses is measured by a rotational rheometer. Specifically, the change of the viscosity of the magnetic liquid with time under the action of different stresses is measured by using a rotational rheometer, so that the starting stress value is selected, and under the action of the starting stress value, the viscosity of the magnetic liquid slowly decreases in a preset time range and finally tends to be stable.
In some embodiments, in step S1, a starting stress value is determined, the magnetic liquid flow is equivalent to a couette flow model under concentric cylinders, and the starting stress value is converted into a driving torque. Therefore, the magnetic liquid flow is equivalent to a Couette flow model under a concentric cylinder, and the starting stress value is conveniently converted into the driving moment.
In some embodiments, in the step S3, the actual rotation speed of the motor 2 is detected with the rotation speed sensor 3 in the step S3. Specifically, carry out real-time detection through speed sensor 3 to the actual rotational speed of motor 2, and upload to controller 5, controller 5 will actual rotational speed and predetermine the rotational speed contrast, when actual rotational speed is less than predetermined rotational speed, speed sensor 3 will continue to detect, when actual rotational speed arrives when predetermineeing the rotational speed, will carry out the S4 step.
Therefore, the magnetic liquid seal starting method provided by the embodiment of the invention has the advantages of being stable in starting, preventing the magnetic liquid from running off, prolonging the service life of the magnetic liquid seal assembly 4 and the like.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A magnetic fluid seal actuation system, comprising:
a magnetic liquid seal assembly;
the motor is connected with the magnetic liquid sealing assembly and used for starting the magnetic liquid sealing assembly;
a rotation speed sensor that detects a rotation speed of the motor;
and the frequency converter is connected with each of the motor and the rotating speed sensor, so that when the motor reaches a preset rotating speed, the frequency converter is switched from a torque control mode to a rotating speed control mode.
2. The magnetic liquid seal actuation system of claim 1, further comprising a rotational rheometer coupled to the magnetic liquid seal assembly for measuring changes in viscosity of the magnetic liquid over time under stress.
3. The magnetic liquid seal actuation system of claim 2, wherein the rotational rheometer is provided with a magnetic field module.
4. The magnetic liquid seal actuation system of any one of claims 1 to 3, further comprising a controller connected to each of the motor, the frequency converter, and the rotational speed sensor.
5. A magnetic fluid seal activation method, comprising the steps of:
s1: measuring the change condition of the viscosity of the magnetic liquid along with time under the action of different constant stresses, and determining the driving torque;
s2: starting a frequency converter to adjust the power of a motor, wherein the frequency converter starts the motor in a torque control mode, and the motor drives a magnetic liquid sealing assembly to rotate by the driving torque;
s3: detecting the rotating speed of the motor in real time;
s4: and when the rotating speed of the motor reaches a preset rotating speed, switching the frequency converter from the torque control mode to a rotating speed control mode so that the motor is smoothly transited to the working rotating speed from the preset rotating speed.
6. The magnetic liquid seal startup method according to claim 5, characterized in that a thixotropic agent is added to the magnetic liquid before the startup of step S1.
7. The magnetic liquid seal startup method of claim 6, wherein the thixotropic agent is clay or a polymer material.
8. The magnetic liquid seal startup method according to claim 5, characterized in that in step S1, the change of the viscosity of the magnetic liquid with time under the action of different stresses is measured by a rotational rheometer.
9. The magnetic fluid seal starting method according to claim 5, wherein in step S1, a starting stress value is determined according to a change in viscosity of the magnetic fluid, the magnetic fluid flow is equivalent to a couette flow model under concentric cylinders, and the starting stress value is converted into the driving torque.
10. The magnetic liquid seal startup method according to claim 5, characterized in that in step S3, the actual rotation speed of the motor is detected with a rotation speed sensor in step S3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110411110.7A CN113217634A (en) | 2021-04-16 | 2021-04-16 | Magnetic liquid sealing starting system and starting method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110411110.7A CN113217634A (en) | 2021-04-16 | 2021-04-16 | Magnetic liquid sealing starting system and starting method |
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| CN113217634A true CN113217634A (en) | 2021-08-06 |
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| CN202110411110.7A Pending CN113217634A (en) | 2021-04-16 | 2021-04-16 | Magnetic liquid sealing starting system and starting method |
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Citations (8)
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|---|---|---|---|---|
| EP0450824A1 (en) * | 1990-04-03 | 1991-10-09 | Lord Corporation | Electroactive fluid torque transmission apparatus with ferrofluid seal |
| JPH09112542A (en) * | 1995-08-30 | 1997-05-02 | Internatl Business Mach Corp <Ibm> | Self-pressurization journal-bearing-assembly |
| CN101963567A (en) * | 2010-09-21 | 2011-02-02 | 中国兵器工业第五二研究所 | Method and device for testing magnetic viscosity of magnetic liquid |
| CN103280943A (en) * | 2013-04-24 | 2013-09-04 | 沈锡鹤 | Magnetorheological power control motor and control method thereof |
| CN103956943A (en) * | 2014-05-13 | 2014-07-30 | 安徽中家智锐科技有限公司 | Efficient brushless direct current motor starting and control method |
| CN104653444A (en) * | 2015-01-30 | 2015-05-27 | 海信科龙电器股份有限公司 | Method and device for controlling starting of variable-frequency air conditioner |
| CN106015579A (en) * | 2016-07-15 | 2016-10-12 | 清华大学 | Mechanical sealing device based on active control of throttling structure |
| CN112178205A (en) * | 2020-10-28 | 2021-01-05 | 清华大学 | Magnetic liquid sealing device and motor with same |
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2021
- 2021-04-16 CN CN202110411110.7A patent/CN113217634A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0450824A1 (en) * | 1990-04-03 | 1991-10-09 | Lord Corporation | Electroactive fluid torque transmission apparatus with ferrofluid seal |
| JPH09112542A (en) * | 1995-08-30 | 1997-05-02 | Internatl Business Mach Corp <Ibm> | Self-pressurization journal-bearing-assembly |
| CN101963567A (en) * | 2010-09-21 | 2011-02-02 | 中国兵器工业第五二研究所 | Method and device for testing magnetic viscosity of magnetic liquid |
| CN103280943A (en) * | 2013-04-24 | 2013-09-04 | 沈锡鹤 | Magnetorheological power control motor and control method thereof |
| CN103956943A (en) * | 2014-05-13 | 2014-07-30 | 安徽中家智锐科技有限公司 | Efficient brushless direct current motor starting and control method |
| CN104653444A (en) * | 2015-01-30 | 2015-05-27 | 海信科龙电器股份有限公司 | Method and device for controlling starting of variable-frequency air conditioner |
| CN106015579A (en) * | 2016-07-15 | 2016-10-12 | 清华大学 | Mechanical sealing device based on active control of throttling structure |
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