CN100432444C - Purifying pump - Google Patents

Abstract

A pure pump belongs to the magnetic levitation pure pump. There is a bearingless motor at both ends of the pump, two left and right motor stators are fixed in the pump casing, and two left and right rotors are fixed in the column wheel, corresponding to the left and right motor stators in the pump casing. Proper control of the current in the stator coils will exert a force on the rotor in the column wheel, thereby not only rotating the column wheel, but also supporting the column wheel and causing it to levitate. The inner wall of the column wheel is equipped with helical column leaves, and when the column wheel rotates, the transmission liquid can be pumped out. Compared with the prior art, the pure pump has the advantages of simple structure, low cost, high power, high integration and simple control.

Description

pure pump

1. Technical field

The invention relates to a pump, in particular to a magnetic levitation pure pump.

2. Background technology

With the development of magnetic levitation technology, its application in the field of pumps is becoming more and more extensive. Its unique advantages such as no friction, no wear, no maintenance, long life and high efficiency provide a new direction for the development of pumps. Such as the following several magnetic levitation pumps.

The Chinese patent No. 02109770.4 is an axially controllable magnetic levitation permanent disk blood pump motor, which consists of a housing, a disk stator, a permanent disk rotor, a passive permanent magnetic bearing, a blood pump impeller and an axially controllable magnetic bearing , the disc stator is wound into a ring by electrical silicon steel sheets, and the stator winding is slotted radially on one end of the ring, and the permanent disc rotor is installed at one end of the non-magnetic rotating shaft, which penetrates the magnetized cylinder The cylindrical permanent magnet and the rotating shaft penetrate into another cylindrical permanent magnet fixed on the casing together, and the other end of the shaft is connected to a blood pump impeller, and the outer part of the corresponding impeller is at the end of the motor. Equipped with axial active magnetic bearings.

The Chinese patent No. 200510005303.3 is a fully artificial heart blood pump without bearings, motors and shafts. The blood pump consists of two symmetrical left and right ventricular blood pumps with the same structure. The blood flow inlet, the funnel-shaped blood pump inner cavity, the cylindrical blood pump inner cavity are connected with the blood flow outlet in sequence. Interconnected cone and column impellers are seated in the funnel and cylindrical blood pump lumens. Both the inner cavity of the funnel-shaped blood pump and the outer wall of the inner cavity of the cylindrical blood pump are provided with multiple sets of coils; the outer wall of the inner cavity of the cylindrical blood pump is also provided with multiple sets of coils. The column impeller is the drive part that acts as a rotor. The force generated by the coil drives the impeller to rotate, and forms the active control of the axial and radial movement of the impeller and the control of the angular displacement and rotational speed of the impeller.

The U.S. Patent No. 7070398 is an axial-flow magnetic levitation blood pump, which includes: a pump casing with a cavity; a rotating impeller located in the cavity; magnetic bearings at both ends make the impeller suspend in the cavity; the shaft A magnetic bearing consists of a series of magnets that keep the impeller axially stable; an electric motor turns the impeller, which in turn pumps blood out.

The U.S. Patent No. 6053705 is a rotary impeller pump, which includes: a pump casing with a cavity and an inlet and outlet; a stator fixed to the pump casing with coils wound on the stator teeth; a rotor with blades that rotates The material to be transported is pumped out; the rotor has a passive suspension device; the current in the coil is controlled to make the rotor suspend and rotate; the rotor has passive suspension capability.

The above maglev pumps have disadvantages such as complex structure, high cost, difficulty in increasing power, low integration, and complicated control.

3. Contents of the invention

1. Purpose of the invention: the problem to be solved by the present invention is to overcome the shortcomings of the existing magnetic levitation pumps, such as complex structure, high cost, difficulty in increasing power, low integration, and complicated control.

2. Technical solution: There is a motor at both ends of the pump. These two motors can not only rotate the impeller but also suspend both ends of the impeller. In the axial direction, the reluctance pulling force of the air gap magnetic field of the motor can be used to achieve suspension; The motors at both ends implement active control according to the radial displacement of the impeller, so that both ends of the impeller are suspended, and the axial direction is a passive suspension, which can also be actively controlled when necessary.

The motors at both ends adopt the magnetic bearing integration technology, which integrates the motor and the magnetic bearing, which is also called bearingless technology or dynamic magnetic bearing technology.

In order to generate a controllable magnetic levitation force in a radial magnetic bearing, it is generally necessary to generate a bias magnetic field first, and then superimpose a levitation magnetic field to achieve the purpose of controlling the levitation force by controlling the levitation magnetic field. Bearingless technology uses the driving magnetic field in the motor as a bias magnetic field, and adds a set of windings to generate a levitating magnetic field to achieve the purpose of generating levitation force. In this way, the drive system of the motor and the radial magnetic bearing system can be combined into one, which greatly shortens the axial length of the motor and improves the axial utilization rate of the motor.

Generally, the bias magnetic field in the magnetic bearing is a constant magnetic field, while the driving magnetic field of the motor is a magnetic field that changes with the rotation of the rotor, which requires this change to be taken into account when controlling the suspension. This leads to a more complex suspension control. However, when the alternating pole permanent magnet rotor is used, the rotation of the rotor does not affect the levitation force, which simplifies the control system.

The pure pump of the present invention includes two types of inner rotor axial flow pump and outer rotor axial flow pump: 1. The specific structure of the inner rotor axial flow pump includes a left end bearingless motor and a right end bearingless motor placed at the left and right ends of the inner cavity of the pump casing. motor, and a column wheel with a helical impeller, the left rotor of the left end bearingless motor and the right rotor of the right end bearingless motor are respectively embedded in the column wheel with a helical impeller, the left stator of the left end bearingless motor and the The right stator of the bearingless motor at the right end is respectively embedded in the inner cavity of the pump casing; the left radial displacement sensor is embedded in the inner side of the left end of the pump casing; the column wheel with the helical impeller is hollow cylindrical, and its inner wall is provided with A helical impeller is installed on the inside of the left stator and the right stator in the pump casing to form an axial flow pump with an inner rotor structure. 2. The specific composition of the outer rotor axial flow pump, including the left end bearingless motor and the right end bearingless motor placed at the left and right ends of the inner cavity of the pump casing, two left and right radial displacement sensors, a column wheel with a helical impeller and a stator column The left rotor of the left end bearingless motor and the right rotor of the right end bearingless motor are respectively embedded in the column wheel with the helical impeller, the left stator of the left end bearingless motor and the right stator of the right end bearingless motor are both The part is fixed on the outside of the stator column, and the stator column is fixed in the inner cavity of the pump casing; the column wheel with the helical impeller is a hollow cylinder, and its inner wall is equipped with or both inner and outer walls are provided with helical impellers, which are set on the stator column The outer side constitutes an axial flow pump with an outer rotor structure.

4. Description of drawings

Figure 1 is an alternating pole permanent magnet rotor structure.

Fig. 2 is the principle of the levitation force generation of the alternating pole permanent magnet rotor, where Fig. (a) is a schematic diagram of generation of force in the x direction, and Fig. (b) is a schematic diagram of generation of force in the y direction.

Figure 3 is a control block diagram of an alternating pole permanent magnet bearingless motor.

Figure 4 is a schematic diagram of axial suspension force generation

Fig. 5 is a schematic structural diagram of an inner rotor axial flow pump.

Fig. 6 is a schematic diagram of a centralized winding structure.

Fig. 7 is a schematic structural diagram of an axial flow pump with an auxiliary axial suspension module in the middle of the inner rotor.

Fig. 8 is a schematic structural diagram of an axial flow pump with auxiliary axial suspension modules at both ends of the inner rotor.

Fig. 9 is a schematic structural diagram of an inner rotor mixed flow pump. The right figure is the B-B sectional view of the left figure.

Fig. 10 is a schematic structural view of an external rotor axial flow pump. The right figure is the A-A sectional view of the left figure.

Fig. 11 is a schematic structural view of an axial flow pump with an auxiliary axial suspension module in the middle of the outer rotor.

Fig. 12 is a schematic structural view of an axial flow pump with auxiliary axial suspension modules at both ends of the outer rotor.

Fig. 13 is a schematic structural view of an outer rotor mixed-flow pump.

The meaning of the symbols in the figure: 1-pump casing, 2-left radial displacement sensor, 3-left stator, 4-right stator, 5-right radial displacement sensor, 6-right rotor, 7-column wheel, 8-left Rotor, 9-axial displacement sensor, 10-stator column, 11-middle auxiliary axial suspension module, 12-left inlet, 13-right inlet, 14-exit, 15-permanent magnetic pole, 16-iron pole, 17- Left end bearingless motor, 18-right end bearingless motor, 19-middle impeller, 20-23-both auxiliary axial suspension modules.

5. Specific implementation

The above-mentioned Figures 1-13 are the specific structural schematic diagrams and working principle diagrams of the pure pump of the present invention. The structural diagram of the alternating pole permanent magnet rotor is shown in Fig. 1, the solid line in the figure represents the permanent magnetic field, and the dotted line represents the levitation magnetic field. It can be seen from the figure that the characteristics of the motor are: only N pole permanent magnets, no S pole permanent magnets, S poles are iron poles, and the permanent magnetic field is only generated by N pole permanent magnets. If it is assumed that the thickness of the permanent magnet is thick enough so that the magnetic field lines of the levitating magnetic field basically only pass through the iron pole, then it can be considered that the levitating bias magnetic field is the magnetic field under the iron pole. The magnetic field under the iron pole is a unipolar magnetic field, and the magnetic field is from the outside to the inside or from the inside to the outside. To generate the levitation force, it is only necessary to add a levitation magnetic field with a pole pair number of 1. After adding a levitation magnetic field with one pair of poles, it can be seen from Figure 2(a) that the magnetic density at the two iron poles on the left (dark shaded area) is enhanced because the direction of the levitation magnetic field and the permanent magnetic field are consistent; And the magnetic density at the two iron poles on the right (light shaded area) is weakened because the directions of the levitation magnetic field and the permanent magnetic field are opposite; thus a magnetic pulling force is generated to the left. Similarly, as shown in Figure 2(b), a downward magnetic pulling force can be generated.

Through the analysis of the bearingless motor with alternating pole permanent magnet rotor, it can be obtained that the formula of its levitation force is (the number of pole pairs is greater than or equal to 4):

F _x ＝k·i _lα

F _y ＝-k·i _lβ

In the formula, F _x and F _y are the levitation forces on the x and y axes respectively, k is the levitation force coefficient, which is related to the structure of the motor and the permanent magnet material, and i _lα and i _lβ are the α and β axis components of the levitation current, respectively.

Design the control system shown in Figure 3 to realize suspension and rotation control. The control system is divided into two subsystems, suspension control and rotation control. The levitation control subsystem controls the current in the levitation winding, and the rotation control subsystem controls the motor main drive winding.

The two ends of the pump are controlled in the above-mentioned way, and the magnetic resistance is used to achieve suspension in the axial direction. The principle is shown in Figure 4. When the rotor deviates from the equilibrium position, according to the principle of the shortest magnetic circuit, a force in the opposite direction will be generated to pull the rotor back to the equilibrium position. Since the reluctance pull generated by the motor itself is limited, an axial auxiliary levitation module can be added if necessary. In the axial flow pump, the transported material flows axially, which will generate an axial reaction force on the rotor, and the rotor deviates from the equilibrium position. By detecting the degree of deviation from the equilibrium position, the transported material can be determined with information such as torque and speed. Viscosity and flow and other information.

The stator of the motor can be a distributed winding or a centralized winding. When a centralized winding is used, as shown in Figure 6, one set of windings can be used to control the suspension and rotation of the rotor at the same time. The principle is: when two sets of windings are used, The original driving magnetic field in the motor is superimposed with the levitation magnetic field to generate the levitation force, and the magnetic field is generated by the energized coil, and the superposition of the magnetic field can correspond to the superposition of the current. When two sets of coils are wound on a stator tooth, the magnetic fields generated by the two sets of coils are superimposed. When a set of coils is used, the current passed into the coil is the superposition of the currents in the original two sets of coils. The magnetic field generated by it is the same as The magnetic fields generated by the two sets of coils are equal.

When controlling the suspension of the motor, a radial displacement signal is required, and the use of a displacement sensor based on a Hall element helps to reduce the cost of the system.

Fix the stator to the pump casing, and fix the rotor to the column wheel. As shown in Figure 5, there are helical impellers on the inside and outside of the column wheel, and the column wheel rotates to pump out the transmission material.

In order to improve the purity of the pump, non-magnetic materials are coated or wrapped on the inner cavity of the pump casing and the column wheel according to the physical and chemical properties of the transported substances.

Describe the concrete structure of the present invention according to above-mentioned Fig. 5 to Fig. 13, can know by above-mentioned figure,

There is a bearingless motor 17 and 18 at both ends of the pump. These two motors can not only rotate the impeller but also suspend the two ends of the impeller. In the axial direction, the reluctance pulling force of the air gap magnetic field of the motor can be used to achieve suspension. , or rely on the auxiliary suspension module to improve performance. According to this principle, there are several specific implementation methods as follows:

1. Figure 5 is an inner rotor axial flow pump, the left stator 3 and the right stator 4 are embedded in the pump casing 1, the left rotor 8 and the right rotor 6 are embedded in the column wheel 7, the left radial displacement sensor 2 and the right The radial displacement sensor 5 is embedded in both ends of the pump casing 1 , and the axial displacement sensor is embedded in the left end of the pump casing 1 . The column wheel is a hollow cylinder with helical impellers on the inner and outer walls. The main purpose of setting the impeller on the outer wall is to promote the flow of transported substances in the air gap between the rotor and the stator, which is of great significance in some fields, such as blood pumps. The column wheel rotates to pump the material being transferred axially. The rotor of this type of pump is subjected to a reaction force in the axial direction. Since the axial force generated by the motor is limited, this type of pump is suitable for occasions with low power.

2. Figure 7 is an axial flow pump with an auxiliary axial suspension module in the middle of the inner rotor, which is based on Figure 5 in the pump casing 1 between the left stator 3 and the right stator 4 and the column wheel with the helical impeller Added auxiliary axial suspension module 11 in 7. The axial load capacity of this type of pump has been improved, and the power of the corresponding pump has also been increased.

3. Figure 8 shows an axial-flow pump with auxiliary axial suspension modules at both ends of the inner rotor. On the basis of Figure 5, auxiliary axial Suspension modules (20, 21, 22, 23). The auxiliary axial suspension module for this type of pump can be either passive or actively controlled. With active control suspension, the axial displacement can be precisely controlled.

4. Figure 9 shows an inner rotor mixed-flow pump. The impeller at the left end of the column wheel is helical, and the impeller at the right end is also helical, but the direction of the helix is opposite to that of the left end impeller. The middle impeller 19 connects the left end and the right end of the column wheel. The transported material is accelerated through the left end impeller and the right end impeller of the column wheel, flows to the middle, and flows out from the middle outlet under the action of the middle impeller 19 . The transmission material is accelerated to the middle through the left end impeller and the right end impeller of the column wheel in the axial flow mode; under the action of the middle impeller 19, the flow out from the middle outlet is in the centrifugal mode. Because the pump is transported in two degrees from the left and right, and flows out in the middle, the column wheel is not stressed in the axial direction, so the pump can achieve greater power.

5. Figure 10 is an axial flow pump with an outer rotor, the stator column 10 is fixed in the inner cavity of the pump casing 1; the left motor stator 3 and the right motor stator 4 are fixed in the stator column 10; the column wheel 7 is set on the stator column 10 Outside; the left motor rotor 8 and the right motor rotor 6 are fixed in the column wheel 7; the left radial displacement sensor 2 and the right radial displacement sensor 5 are embedded in both ends of the pump casing 1, and the axial displacement sensor is embedded in the left end of the pump casing 1. The column wheel is a hollow cylinder with helical impellers on the inner and outer walls. This type of pump is suitable for occasions with low power.

6. Figure 11 shows an axial flow pump with an auxiliary axial suspension module in the middle of the outer rotor, which is based on Figure 10 with an auxiliary axial suspension module 11 added. The axial load capacity of this type of pump has been improved, and the power of the corresponding pump has also been increased.

7. Figure 12 shows an axial flow pump with auxiliary axial suspension modules at both ends of the outer rotor. On the basis of Figure 10, auxiliary axial suspension modules are respectively added to the inner ends of the left and right ends of the stator column 10 (20, 21, 22, 23). The auxiliary axial suspension module for this type of pump can be either passive or actively controlled. Axial displacement can be precisely controlled.

8. Figure 13 is an external rotor mixed flow pump. The impeller at the left end of the column wheel is helical, and the impeller at the right end is also helical, but the direction of the helix is opposite to that of the left end impeller, and the diameter of the middle outlet is larger than that of the inlets at both ends. The transported material is accelerated towards the outlet under the axial and centrifugal force of the impeller. Because the pump is transported in two degrees from the left and right, and flows out in the middle, the column wheel is not stressed in the axial direction, so the pump can achieve greater power.

The above are several typical examples of the present invention, those skilled in the art can make changes to the present invention from shape to details under the guiding principle of the present invention.

Claims (2)

1. A pure pump, including a left-end bearingless motor (17) and a right-end bearingless motor (18) placed at the left and right ends of the inner cavity of the pump casing (1), and two left and right radial displacement sensors (2, 5) , and a column wheel (7) with a spiral impeller, the left rotor (8) of the left end bearingless motor (17) and the right rotor (6) of the right end bearingless motor (18) are respectively embedded with a spiral In the column wheel (7) of the impeller, the left stator (3) of the bearingless motor (17) at the left end and the right stator (4) of the bearingless motor (18) at the right end are respectively embedded in the inner cavity of the pump casing (1); The displacement sensor (2) is embedded in the inner side of the left end of the pump casing (1); the right radial displacement sensor (5) is embedded in the inner side of the right end of the pump casing (1); the column wheel (7) with a helical impeller is hollow cylindrical, and its inner wall A helical impeller is installed inside the left stator (3) and the right stator (4) in the pump casing (1). The structure of the left rotor (8) and the right rotor (6) is an alternating pole permanent magnet rotor. The permanent magnet poles (15) and iron poles (16) are distributed alternately, and it is characterized in that the left stator (3) of the left end bearingless motor (17) and the right stator (4) of the right end bearingless motor (18) are both Distributed windings or concentrated windings are used to generate the driving magnetic field and levitation magnetic field that simultaneously control the left rotor (8) and the right rotor (6). The left impeller and the right impeller of the column wheel (7) with spiral impellers are both spiral shape, but the spiral directions of the two are opposite, and the left and right impellers are connected through the middle impeller (19). There is a middle outlet in the middle of the pump casing, and the transported material flows in axially from both ends and flows out through the middle outlet. Thus constitute the internal rotor mixed flow pump. 2. A pure pump, including a left-end bearingless motor (17) and a right-end bearingless motor (18) placed at the left and right ends of the inner cavity of the pump casing (1), and two left and right radial displacement sensors (2, 5) , a column wheel (7) and a stator post (10) with a spiral impeller; the left rotor (8) of the left end bearingless motor (17) and the right rotor (6) of the right end bearingless motor (18) ) are respectively embedded in the column wheel (7) with the helical impeller, the left stator (3) of the bearingless motor (17) at the left end and the right stator (4) of the bearingless motor (18) at the right end are evenly fixed on the stator column ( 10) Outside, the stator column (10) is fixed in the inner cavity of the pump casing (1); the left radial displacement sensor (2) is embedded outside the left end of the stator column (10), and the right radial displacement sensor (5) is embedded in the stator column (10) outside the right end; the column wheel (7) with the spiral impeller is hollow cylindrical, and its inner wall is provided with a spiral impeller, which is sleeved on the outside of the stator column (10). The left rotor (8) and the right rotor (6) ) structure is an alternating pole permanent magnet rotor, permanent magnet poles (15) and iron poles (16) are distributed alternately, it is characterized in that, the left stator (3) of the left end bearingless motor (17) and the right end bearingless motor ( The right stator (4) of 18) adopts distributed winding or centralized winding to generate a driving magnetic field and a levitating magnetic field that simultaneously control the left rotor (8) and the right rotor (6), and the column wheel (7 ) The left impeller and the right impeller are helical, but the helical directions of the two are opposite, and there is a middle outlet (14) whose diameter is larger than the left and right inlet diameters at both ends of the pump casing (1) in the middle of the pump casing (1), Constitute the external rotor mixed flow pump.

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