CN216144136U

CN216144136U - Asynchronous electric heating assembly of outer rotor

Info

Publication number: CN216144136U
Application number: CN202122019672.5U
Authority: CN
Inventors: 刘哲民
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-08-26
Filing date: 2021-08-26
Publication date: 2022-03-29
Anticipated expiration: 2031-08-26

Abstract

The utility model discloses an outer rotor asynchronous electric heating assembly which comprises a stator assembly, wherein the stator assembly comprises a stator shaft and iron core units, an iron core of each iron core unit is provided with a plurality of groups of three-phase windings in a winding mode, and the plurality of groups of three-phase windings are grouped along the circumferential direction; at least one group of windings in the plurality of groups of three-phase windings are power windings, the other groups of three-phase windings are heating windings, and the torques generated by the heating windings are mutually offset; a rotor assembly: the rotor assembly comprises end covers which are arranged at two ends of the stator shaft through bearings; a rotor cylinder made of ferromagnetic material is arranged between the two end covers; the rotor drum and the end covers at the two ends form a closed heating cavity; the stator assembly is positioned in the heating cavity. The heating efficiency of the utility model is greatly improved, the electric energy input from the outside is used for heating except for driving rotation, no other heat loss of connection exists, and when steam is heated, the whole pipeline system is very long, and the heat loss is very large.

Description

Asynchronous electric heating assembly of outer rotor

Technical Field

The utility model belongs to drying equipment, and particularly relates to an outer rotor asynchronous electric heating assembly applied to occasions where driven objects need to be heated.

Background

Heating is a process link often used in industrial production, such as in the industries of printing and dyeing, chemical fiber, textile, papermaking, and the like; the following description is made by taking the papermaking production as an example, a drying cylinder is used in the papermaking production process, the traditional drying cylinder is generally a steam type drying cylinder, the drying cylinder is generally designed by adopting an axially rotating roller, wet paper can be more smooth and rotate on the drying cylinder, the moisture is evaporated by the temperature in the steam drying cylinder, and the moisture is taken away by exhaust air, so that the drying of the paper is realized; with the development of the technology, the electric heating drying cylinder appears in the prior art, and the electric heating drying cylinder gradually replaces the traditional steam drying cylinder, so that the aims of energy conservation and environmental protection are achieved.

The applicant has investigated and searched for technical documents on the prior art, which discloses a class of drying cylinders electrically heated by electromagnetic induction heating, such as: CN 1560551A: this prior art discloses an electromagnetic induction drying cylinder. The drying machine comprises a frame, wherein a transmission shaft and a reduction gearbox are arranged on the frame, a drying cylinder body is arranged on the transmission shaft, a drying cylinder cover is arranged on the drying cylinder body, an electromagnetic induction coil and a crystalline ceramic glass protective layer are arranged on the inner side of the drying cylinder cover, and the electromagnetic induction coil is connected with a collecting ring, a high-frequency power supply and an automatic control system. The prior art utilizes an electromagnetic induction heating principle, and aims to change the heat transfer mode of a heat-conducting medium of a traditional drying cylinder, steam, oil or certain gas is not required to be used as the heat-conducting medium, and the drying cylinder has the advantages of simple structure, high heat efficiency and stable performance; because the electromagnetic induction heating is utilized, the heat efficiency is improved, the production cost is obviously reduced, and the pollution to the environment is improved.

CN102041706A this prior art discloses a device for drying paper by heating metal bands in sections, which comprises a large-diameter drying cylinder, a metal heating band device and a wet air suction box, wherein the metal heating band device is uniformly installed on the outer cylindrical surface of the large-diameter drying cylinder below a paper feeding guide roller and a paper discharging guide roller, the metal heating band device comprises a metal band, a guiding tensioning driving roller supported in the metal band, and an electromagnetic induction heater, two of the guiding tensioning driving rollers are pressed on the outer cylindrical surface of the large-diameter drying cylinder in the same diameter, one of the driving rollers is connected with a motor, and the electromagnetic induction heater is installed inside each metal band. In the prior art, the paper sheet is wrapped on the large-diameter drying cylinder in sections by using the metal belt capable of being heated by electromagnetic induction to heat and dry the paper sheet, so that the thermal resistance between a heating body and the surface of the paper sheet is reduced, the drying efficiency is improved, the length of a drying part can be shortened, the difference between two surfaces of the dried paper sheet is minimized, and the drying shrinkage of the paper sheet is limited, thereby improving the tensile strength of the paper sheet. The existing drying cylinder generally comprises a drying cylinder body which is heated in an electromagnetic induction heating mode and is driven by a driving motor to rotate, so that the drying cylinder body reaches the specified drying temperature, and the problems of energy conservation and environmental protection are solved; existing reservoirs are relatively complex in structure.

This prior art of CN108867140A discloses a papermaking drying device, it relates to stoving technical field. The device comprises a heat transfer component, a heat conducting roller, a drying cylinder, an electromagnetic induction coil, a connecting pipe, a heater and a temperature sensor; the heat transfer assemblies, the heat conducting rollers, the electromagnetic induction coils and the temperature sensors are all arranged inside the drying cylinder, the number of the heat transfer assemblies is four, the four heat transfer assemblies are respectively and correspondingly arranged on the surfaces of the heat conducting rollers, the electromagnetic induction coils are arranged inside the heat conducting rollers, the temperature sensors are arranged at the right ends of the heat conducting rollers, and the heat conducting rollers and the temperature sensors are connected to the heaters through connecting pipes; the utility model has the beneficial effects that: this prior art aim at has solved traditional papermaking technology drying efficiency low, the complicated problem of drying equipment, through the optimization of power converter, makes drying device structure simpler, and the installation more adapts to service environment, utilizes the design of electromagnetic induction coil position to avoid forming the water droplet at electromagnetic induction coil because of moisture toasts the steam condensation after the evaporation to improve the quality of paper production.

CN201193299Y this prior art discloses an electromagnetic induction type paper machine drying cylinder for drying paper pulp by applying electromagnetic induction heating principle, at least one set of electromagnetic induction coils is arranged outside the side wall of the drying cylinder rotating axially, alternating current is passed through the electromagnetic induction coils to make the electromagnetic induction coils generate a high speed changing magnetic field, when the magnetic force lines in the magnetic field pass through the drying cylinder, strong eddy current is generated in the drying cylinder, and the drying cylinder itself is in short circuit state, so the eddy current generates heat at high speed by itself under the action of the resistance of the drying cylinder itself, thereby realizing the conversion of electric energy and heat energy, and achieving the purpose of drying and drying paper. The drying cylinder does not need other heating bodies for heating, the drying cylinder heats by self resistance under the action of an electromagnetic field, and multiple energy conversion and heat conduction processes are avoided, so that energy can be greatly saved, the heating speed is higher, and the automatic control is easier to realize.

CN200999312Y this prior art discloses a built-in magnetic flux generator electromagnetism dryer and strutting arrangement thereof, belongs to the papermaking machinery field. The drying cylinder is characterized in that the drying cylinder is cylindrical, two ends of the drying cylinder are open, and the drying cylinder is supported by three support rolls which are arranged in parallel, wherein two support rolls are positioned on two sides of the lower part of the drying cylinder, and the other support roll is positioned on the inner side of the top of the drying cylinder. The drying cylinder is cylindrical, two ends of the drying cylinder are open, so that the air in the drying cylinder has good fluidity, the temperature of the built-in electromagnetic induction coil is easy to control, and accidents caused by the electromagnetic induction coil are not easy to damage. The utility model has reasonable design, long service life and convenient installation and use.

Through the analysis of the prior art, the prior heating mode is generally electromagnetic heating, and the operation and the heating are realized by matching with a driving motor, so that the technical defects exist, the prior art has the defects of complicated structure and tedious maintenance due to the existence of independent driving and electromagnetic heating parts, and particularly, the shutdown maintenance is directly caused by the damage of the motor or the damage of the electromagnetic heating; the comprehensive contrast is relatively high from the aspect of energy consumption.

The utility model designs and develops an outer rotor asynchronous electric heating assembly and drying equipment based on the working principle of a motor.

SUMMERY OF THE UTILITY MODEL

Aiming at the problems in the prior art, the utility model provides an outer rotor asynchronous electric heating assembly.

The utility model is realized in this way, an outer rotor asynchronous electric heating assembly, which is characterized in that: the stator assembly comprises a stator shaft, and iron core units which are arranged on the stator shaft, are independent from each other and are distributed on the stator shaft at equal intervals, wherein each iron core unit comprises an iron core bracket and an iron core arranged on the iron core bracket; the iron core of each iron core unit is provided with a plurality of groups of three-phase windings in a winding way, and the plurality of groups of three-phase windings are grouped along the circumferential direction; at least one group of windings in the plurality of groups of three-phase windings are power windings, the other groups of three-phase windings are heating windings, and the torques generated by the heating windings are mutually offset; a rotor assembly: the rotor assembly comprises end covers which are arranged at two ends of the stator shaft through bearings; a rotor cylinder made of ferromagnetic material is arranged between the two end covers; the rotor drum and the end covers at the two ends form a closed heating cavity; the stator assembly is positioned in the heating cavity.

Preferably, the clearance between the outer wall of the core unit and the inner wall of the rotor barrel is 0.5mm-7.5 mm.

Preferably, the stator further comprises a middle iron core support unit, the middle iron core support unit is installed on the stator shaft at equal intervals, an iron core is installed on each middle iron core support unit, a plurality of groups of heating three-phase windings are wound on each iron core, the plurality of groups of heating three-phase windings are divided into two groups, the direction of a rotating magnetic field generated by one group of heating windings is opposite to the direction of a rotating magnetic field generated by the other group of heating windings, and torques generated by the two groups of heating windings are mutually offset.

Preferably, the inner wall and/or the outer wall of the end cap can be provided with a thermal insulation layer.

The utility model has the advantages and technical effects that: the utility model is designed by utilizing the working principle of the motor, the outer rotor drum is used as a drying cylinder for heating, the rotor drum is equivalent to the rotor of the motor, at least one set of three-phase winding is used as a driving winding to drive the rotor drum to move, the rotating motion of the rotor drum is met, and the rotating speed of the rotor drum is adjusted by adjusting the power supply voltage and frequency of the driving winding; at the moment, the driving winding and the rotor drum form an ultra-low efficiency motor, the motor outputs mechanical power to drive the drying cylinder to rotate, the loss of the rotor drum is small, so that the generated heat is relatively small, and the heat generated by the driving winding cannot meet the temperature required by the drying cylinder; it is well known that the higher the efficiency of a motor in an ideal state as a mechanical output, the better, the less the heat generation, the better; through reverse thinking, under the condition that one set of winding meets the requirement of rotary driving, a plurality of sets of three-phase windings are arranged in the rotor barrel for heating, except the driving winding, each set of other heating winding and the rotor barrel form an independent motor, but in order to increase the loss of the rotor barrel, the utility model adopts the mode that except the driving winding, the other windings are energized with currents with the same frequency and opposite directions, the direction of a rotary magnetic field generated by one set of heating winding is opposite to the direction of a rotary magnetic field generated by the other set of hot winding, so that the torques generated by the two sets of heating windings are mutually offset, the loss of the rotor barrel is larger under the condition, the rotor barrel generates heat, and the heating of the rotor barrel is controlled.

In summary, compared with the traditional steam drying cylinder, the heating efficiency of the traditional steam drying cylinder is greatly improved, the electric energy input from the outside is used for driving the rotation and is also used for heating, no other heat loss of connection exists, and when steam is heated, the whole pipeline system is long and the heat loss is large. Meanwhile, high-pressure steam is not used, and a pressure container is not needed any more, so that the safety of the system is reduced.

Compared with the electromagnetic induction type drying disclosed by the prior art, the drying device has the following advantages.

1. An external driving device is not needed, and the energy efficiency is further improved.

2. In the traditional electromagnetic or steam drying device, the utility model also has the redundancy characteristic. If the driving motor fails, stopping for maintenance, and at this time, a large amount of waste materials can be generated in the entered raw materials, even the materials are accumulated, so that more waste materials are frequently generated, and the cost of the waste materials caused by the failure of each time according to on-site estimation is higher than that of one motor.

3. When the heating part has a fault, the system can also continue to work by adjusting the power supply state of the winding.

Drawings

FIG. 1 is a schematic structural view of example 1 of the present invention;

fig. 2 is a schematic structural diagram of embodiment 2 of the present invention.

In the figure, 1, a stator assembly; 1-1, a stator shaft; 1-2, iron core support; 1-3, iron core; 1-4, three-phase winding; 2. a rotor assembly; 2-1, end cover; 2-2, a rotor drum; 2-3, a bearing; 2-4, heating the cavity; 2-5, a heat insulation layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

Embodiment 1, please refer to fig. 1, the present invention relates to an external rotor asynchronous electric heating assembly, which includes a stator assembly 1, wherein the stator assembly includes a stator shaft 1-1, and two iron core units 1-2, which are installed on the stator shaft, are independent from each other, and are distributed on the stator shaft at equal intervals. The iron core unit comprises iron core supports 1-20 and iron cores 1-21 arranged on the iron core supports; an iron core of each iron core unit is provided with a plurality of groups of three-phase windings 1-3 in a winding mode, and the plurality of groups of three-phase windings are grouped along the circumferential direction; at least one group of three-phase windings is a power winding, the other groups of three-phase windings are heating windings, the torques generated by the heating windings are mutually offset, for example, the groups of three-phase windings are divided into two groups, wherein the direction of a rotating magnetic field generated by one group of heating windings is opposite to that of a rotating magnetic field generated by the other group of heat windings, so that the torques generated by the two groups of heating windings are mutually offset, and the change of the opposite rotating magnetic fields belongs to the known technology, for example, the change of the phase sequence of the current in the stator winding is realized; the number of the iron cores is reduced under the condition of independent split, the distance between the iron core sections needs to meet the requirement of the length of the end part due to the existence of the end part of the winding, but each iron core section and the winding can be manufactured respectively to form modules, and the modules with different numbers are assembled according to the design requirement, so that the standardized and generalized production is facilitated. A rotor assembly: the rotor assembly comprises end covers 2-1 which are arranged at two ends of the stator shaft through bearings 2-3; a rotor cylinder 2-2 made of ferromagnetic material (generally steel plate) is arranged between the two end covers; the rotor cylinder and end covers at two ends form a closed heating cavity 2-4; the stator assembly is positioned in the heating cavity.

In embodiment 2, please refer to fig. 2, the stator further includes three middle iron core support units, the three middle iron core support units are installed on the stator shaft at equal intervals, the iron core of each middle iron core unit is wound with multiple sets of three-phase heating windings, the multiple sets of three-phase heating windings are divided into two sets, a direction of a rotating magnetic field generated by one set of heating windings is opposite to a direction of a rotating magnetic field generated by the other set of hot windings, so that torques generated by the two sets of heating windings are cancelled out. The embodiment is suitable for occasions with large heating quantity requirements, such as printing and dyeing, chemical fiber, textile and papermaking.

In use, the rotor drum is rotated at a desired rotational speed by adjusting the magnitude and frequency of the voltage applied to the drive windings. In this case, the drive winding itself generates heat due to loss due to the presence of the resistor, and the core of the stator also generates heat due to eddy current loss and hysteresis loss due to the alternation of the magnetic field, but the amount of heat is relatively small. The heat of the stator drive winding and the core heats the surrounding air and is finally conducted to the rotor drum, so that the rotor drum is heated. Meanwhile, the rotor barrel generates eddy current and magnetic hysteresis loss due to the alternation of the magnetic field, the rotor barrel is directly heated, and the heat of the rotor barrel is used for heating a target object.

Because the voltage and the frequency of the driving winding need to be given according to the requirement of the rotating speed, the heat of the rotor barrel cannot be independently adjusted by adjusting the voltage and the frequency of the driving winding; the heating winding is used for solving the problem of heat (temperature) control of the rotor barrel. When in design, the heating value caused by the driving winding is smaller than the working requirement, and the temperature of the rotor cylinder is lower than the requirement; other heat is generated by the heat generation winding operation so as to adjust the heat generation amount (temperature) of the rotor drum.

When a set of heating winding works independently, the condition is the same as that when the driving winding works independently, when the heating winding works together with the driving winding, the heating caused by the heating winding is superposed on the rotor drum, the temperature of the rotor drum rises, the rotating speed requirement of a driving task can not be considered by the heating winding, and voltage with higher frequency is applied, so that eddy current and hysteresis loss are caused to be larger, and the heating is facilitated. However, the heating winding also generates a torque for rotating the rotor drum, the torque is superposed on the torque of the driving winding, the rotating speed of the rotor drum can fluctuate, the rotating speed fluctuation can fluctuate the slip ratio, and the heating value also fluctuates. The two or more sets of paired heating windings are used for heating and simultaneously offsetting the torque, so that the rotor drum can run stably.

Preferably, the clearance between the outer wall of the iron core and the inner wall of the rotor barrel is 0.5-7.5 mm, the clearance is too small, the mechanical processing requirement is high, the processing difficulty is high, and mechanical faults are easy to occur during operation; the gap is too large, the magnetic resistance of the gap is too large, a larger current is needed to establish a magnetic field, the stator loss ratio is larger, the heat of the stator needs to be conducted to the rotating drum through the air gap, and the heat conduction efficiency is reduced. Generally, the rotor has a large diameter and a long length, and the rotor has a large gap value in rotation according to the values of the diameter and length of the rotor cylinder.

Preferably, the inner wall and/or the outer wall of the end cap may be provided with an insulating layer 2-5. The heat dissipation device is used for reducing the outward heat dissipation at the two end covers, reducing the heat loss and improving the heat utilization efficiency.

The following examples are specifically cited for illustration: this example is used for the final drying process of a paper machine. The outer diameter of the rotor barrel is 3.6 meters, the length of the rotor barrel is 4 meters, the length of each iron core unit is 500mm, the gap between an iron core and the rotor barrel is 4mm, the maximum heating power is 300kW, the working temperature of the rotor barrel is 120 ℃, the working rotating speed of the rotor barrel is 120r/min, and the contact surface of paper and the rotor barrel is 2/3 of the circumference.

When starting, the same frequency voltage is applied and the rotation direction is the same, at this time, the rotor drum is driven to start quickly to reach the working rotation speed. And after the working rotating speed is reached, keeping the voltage and the frequency of the intermediate unit unchanged. The other two units are powered off and then applied with the same frequency at the same time, but the voltage direction makes the rotation directions of the two motors opposite, the frequency is increased, the rotor drum is heated to gradually reach the working temperature, the temperature is monitored at any time, the frequency and the voltage of the two motors are dynamically adjusted to keep the temperature constant, the whole device enters the working state, and the wet paper is dried on the rotor drum.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The utility model provides an asynchronous electric heating assembly of outer rotor which characterized in that: the stator assembly comprises a stator shaft, and iron core units which are arranged on the stator shaft, are independent from each other and are distributed on the stator shaft at equal intervals, wherein each iron core unit comprises an iron core bracket and an iron core arranged on the iron core bracket; the iron core of each iron core unit is provided with a plurality of groups of three-phase windings in a winding way, and the plurality of groups of three-phase windings are grouped along the circumferential direction; at least one group of windings in the plurality of groups of three-phase windings are power windings, the other groups of three-phase windings are heating windings, and the torques generated by the heating windings are mutually offset; a rotor assembly: the rotor assembly comprises end covers which are arranged at two ends of the stator shaft through bearings; a rotor cylinder made of ferromagnetic material is arranged between the two end covers; the rotor drum and the end covers at the two ends form a closed heating cavity; the stator assembly is positioned in the heating cavity.

2. The external rotor asynchronous electric heating assembly of claim 1, wherein: the clearance between the outer wall of the iron core unit and the inner wall of the rotor barrel is 0.5mm-7.5 mm.

3. The external rotor asynchronous electric heating assembly of claim 1, wherein: the iron core units are at least two and are positioned at two ends of the stator shaft in the heating cavity.

4. The external rotor asynchronous electric heating assembly of claim 3, wherein: the stator comprises a stator shaft, a stator core unit and a plurality of groups of heating three-phase windings, wherein the stator shaft is provided with a plurality of groups of heating three-phase windings, the stator shaft is provided with a plurality of groups of intermediate iron core units, the intermediate iron core units are arranged on the stator shaft at equal intervals, the iron core of each intermediate iron core unit is wound with the plurality of groups of heating three-phase windings, the plurality of groups of heating three-phase windings are divided into two groups, the direction of a rotating magnetic field generated by one group of heating windings is opposite to the direction of a rotating magnetic field generated by the other group of heating windings, and the torques generated by the two groups of heating windings are mutually offset.

5. The external rotor asynchronous electric heating assembly of claim 1, wherein: the inner and/or outer wall of the end cap may be provided with a thermally insulating layer.