A series electric permanent magnetic liquid seal

Abstract

The application discloses a series type electric permanent magnetic magnetic liquid sealing device, which is characterized by comprising a shaft, a shell, a first pole shoe, a second pole shoe, a third pole shoe, a fourth pole shoe, a permanent magnet, an electric permanent magnet, an exciting coil and a magnetic liquid. The application adopts a novel magnetic circuit design, changes the traditional permanent magnet into an electric permanent magnet, changes the magnetic pole direction of the electric permanent magnet, changes the number of sealing pole teeth, solves the problem of pressure maintaining parking sealing failure of the existing magnetic liquid sealing device, and greatly helps to solve the problem of excessive starting torque of the existing sealing device.

Description

Technical fields:

[0001] This invention relates to the field of mechanical engineering sealing technology, and in particular to a series electro-permanent magnet magnetic liquid sealing device. Background technology:

[0002] Magnetic fluid seals are widely used in chemical, medical, and aerospace fields due to their advantages such as zero leakage, high reliability, and low power consumption. Shear thinning is one of the rheological characteristics of magnetic fluids, which results in the starting torque of the seal being much greater than the normal operating torque. For some high-precision equipment, there are strict requirements for the starting torque in low-temperature environments. Magnetic fluid seals typically employ redundant designs, which further increases the starting torque. Ensuring pressure resistance while reducing the starting torque is a crucial problem that urgently needs to be solved. Summary of the Invention:

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, the purpose of this invention is to propose a series-type electro-permanent magnet magnetic liquid sealing device, which changes the magnetic circuit design of the existing magnetic liquid seal by replacing the permanent magnet with an electro-permanent magnet. By changing the magnetic pole direction of the electro-permanent magnet, the number of sealing pole teeth can be changed. This device can solve the problem of excessive starting torque during the start-up process of the magnetic liquid sealing device itself, and can also prevent the sealing device from failing when it stops under pressure.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A series-connected electro-permanent magnet magnetic liquid sealing device, characterized in that it includes a shaft, a housing, a left bearing, a left sleeve, a first pole shoe, a second pole shoe, a third pole shoe, a fourth pole shoe, a sealing ring, a right sleeve, a right bearing, bolts, an end cap, a left permanent magnet, an electro-permanent magnet, an excitation coil, a right permanent magnet, and a magnetic liquid.

[0007] The connections between the various parts constituting this sealing device are as follows:

[0008] Sealing rings are installed on the first, second, third, and fourth pole shoes, and the excitation coil is wound around the outside of the electro-permanent magnet.

[0009] Inside the housing, the left bearing, left sleeve, first pole shoe, left permanent magnet, second pole shoe, electro-permanent magnet, excitation coil, third pole shoe, right permanent magnet, fourth pole shoe, right sleeve, right bearing, and end cap are installed in series and then tightened with bolts. The shaft is then installed in place by passing it through the left and right bearings, and magnetic fluid is injected into the gap between the shaft and each pole shoe.

[0010] The left and right permanent magnets adopt a ring structure, are axially magnetized, and are made of neodymium iron boron.

[0011] The electro-permanent magnet adopts a ring structure, is axially magnetized, and is made of AlNiCo.

[0012] The edge of the excitation coil maintains a certain distance from the adjacent pole shoes on both sides;

[0013] When the left permanent magnet, the electro-permanent magnet, and the right permanent magnet are installed, the magnets on both sides of the pole shoe have the same polarity;

[0014] The magnetic liquid sealing device operates in a low-temperature environment. During normal startup, when the starting torque requirement is exceeded, an electrical pulse is applied to the excitation coil, causing the poles of the electro-permanent magnet to change. The pole distribution of the permanent magnet and the electro-permanent magnet becomes NSNSNS, meaning only the magnetic liquid at the pole teeth of the first and fourth pole shoes provides a sealing effect. This minimizes the starting torque required and meets the startup requirements. When the seal fails or the device stops due to pressure maintenance during operation, an electrical pulse can be applied to the excitation coil again, causing the poles of the electro-permanent magnet to change again. The pole distribution of the permanent magnet and the electro-permanent magnet becomes NSSNNS, meaning the magnetic liquid at all four pole shoes provides a sealing effect, increasing the pressure resistance.

[0015] In addition, a series-type electro-permanent magnet magnetic liquid sealing device according to the above embodiments of the present invention may also have the following additional technical features:

[0016] In one embodiment of the present invention, each pole piece has 1-14 pole teeth.

[0017] In one embodiment of the present invention, the sealing gap between the shaft and the pole shoe is 0.05-0.15 mm.

[0018] In one embodiment of the present invention, the edge of the excitation coil is kept at a certain distance from the adjacent pole shoes on both sides.

[0019] In one embodiment of the present invention, the electro-permanent magnet, consisting of an electro-permanent magnet and an excitation coil, is located in the middle of the sealing device or on the side close to the outside air.

[0020] In one embodiment of the present invention, the left and right permanent magnets are not fully magnetized. Attached image description:

[0021] Figure 1 This is a schematic diagram of the magnetic liquid sealing structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the multi-loop magnetic circuit of the present invention;

[0023] Figure 3 This is a schematic diagram of the single-loop magnetic circuit of the present invention;

[0024] Explanation of reference numerals in the attached figures:

[0025] 1-Shaft, 2-Housing, 3-Left bearing, 4-Left sleeve, 5-First pole shoe, 6-Second pole shoe, 7-Third pole shoe, 8-Fourth pole shoe, 9-Sealing ring, 10-Right sleeve, 11-Right bearing, 12-Bolt, 13-End cap, 14-Left permanent magnet, 15-Electro-permanent magnet, 16-Excitation coil, 17-Right permanent magnet, 18-Magnetic fluid; Detailed implementation method:

[0026] The present invention will now be described in detail with reference to the accompanying drawings.

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, embodiments of the invention are described in detail below, providing further elaboration. It should be understood that the following embodiments are intended to explain the invention but are not intended to limit it.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] The following description, with reference to the accompanying drawings, describes a series-connected electro-permanent magnet magnetic liquid sealing device according to an embodiment of the present invention.

[0030] Figure 1 This is a schematic diagram of the structure of a series electro-permanent magnet magnetic liquid sealing device according to the present invention.

[0031] like Figure 1 As shown, the sealing device includes components such as a shaft, a housing, pole shoes, a permanent magnet, an electro-permanent magnet, and an excitation coil.

[0032] The permanent magnet adopts a ring structure, is axially magnetized, and is made of neodymium iron boron.

[0033] The electro-permanent magnet adopts a ring structure, is axially magnetized, and is made of AlNiCo.

[0034] The pole shoes are installed in series, and the number of pole shoes is selected according to the pressure resistance requirements.

[0035] Each pole shoe has 1-14 pole teeth.

[0036] The sealing gap between the shaft and the pole shoe is 0.05-0.15mm.

[0037] The edge of the excitation coil maintains a certain distance from the adjacent pole shoes on both sides.

[0038] The electro-permanent magnet, consisting of an electro-permanent magnet and an excitation coil, is located in the middle of the sealed device or on the side close to the outside air.

[0039] When installing permanent magnets and electro-permanent magnets, the magnets on both sides of the pole shoe have the same polarity.

[0040] Figure 2 This is a schematic diagram of the multi-circulation magnetic circuit of a series electro-permanent magnet magnetic liquid sealing device of the present invention.

[0041] During the sealing process, the permanent magnet and the electro-permanent magnet have a pole distribution of NSSNNS, with identical poles on both sides of the pole shoe. Magnetic lines of force originate from the N pole of the magnet, pass through the left pole shoe teeth to the shaft, then through the right pole shoe teeth, and finally return to the S pole of the magnet. Magnetic lines of force pass through all pole shoe teeth, forming a multi-loop magnetic circuit distribution. The magnetic fluid is magnetically confined to the pole teeth of each pole shoe, achieving a seal. At this point, the sealing device has the strongest pressure resistance and is suitable for pressure-maintaining shutdown.

[0042] Figure 3 This is a schematic diagram of a single-cycle magnetic circuit of a series electro-permanent magnet magnetic liquid sealing device according to the present invention.

[0043] During the sealing process, an electrical pulse is applied to the excitation coil, causing a change in the magnetic poles of the electro-permanent magnet. The magnetic pole distribution of the permanent magnet and the electro-permanent magnet becomes NSNSNS. Magnetic field lines originate from the N pole of the left permanent magnet, pass through the first pole shoe teeth to the shaft, and then through the fourth pole shoe teeth to the S pole of the right permanent magnet. The magnetic field lines emanating from the N pole of the right permanent magnet pass through the third pole shoe body to the S pole of the electro-permanent magnet, and the magnetic field lines emanating from the N pole of the electro-permanent magnet pass through the second pole shoe body to the S pole of the left permanent magnet, forming a single-loop magnetic circuit distribution. No magnetic field lines pass through the pole teeth of the second and third pole shoes. The magnetic fluid is magnetically confined to the pole teeth of the first and fourth pole shoes, achieving a seal. At this point, the pressure resistance requirements are met, and the starting torque of the sealing device is minimized.

[0044] Specific implementation methods

[0045] The magnetic fluid sealing device operates in a low-temperature environment. During normal startup, when the starting torque requirement is exceeded, an electrical pulse is applied to the excitation coil, causing a change in the poles of the electro-permanent magnet. The pole distribution of the permanent magnet and the electro-permanent magnet becomes NSNSNS, meaning only the magnetic fluid at the pole teeth of the first and fourth pole shoes provides a sealing effect. This minimizes the starting torque required and meets the startup requirements. If the seal fails during operation or the device stops due to pressure maintenance, an electrical pulse can be applied to the excitation coil again, causing another change in the poles of the electro-permanent magnet. The pole distribution of the permanent magnet and the electro-permanent magnet becomes NSSNNS, meaning the magnetic fluid at all four pole shoes provides a sealing effect, increasing the pressure resistance.

Claims

1. A series-connected electro-permanent magnet magnetic liquid sealing device, characterized in that, Includes shaft (1), housing (2), left bearing (3), left sleeve (4), first pole shoe (5), second pole shoe (6), third pole shoe (7), fourth pole shoe (8), sealing ring (9), right sleeve (10), right bearing (11), bolt (12), end cap (13), left permanent magnet (14), electro-permanent magnet (15), excitation coil (16), right permanent magnet (17), and magnetic fluid (18); The connections between the various parts constituting this sealing device are as follows: Sealing rings (9) are installed on the first pole shoe (5), the second pole shoe (6), the third pole shoe (7), and the fourth pole shoe (8). The excitation coil (16) is wound around the outside of the electro-permanent magnet (15). Inside the outer casing (2), the left bearing (3), left sleeve (4), first pole shoe (5), left permanent magnet (14), second pole shoe (6), electro-permanent magnet (15), excitation coil (16), third pole shoe (7), right permanent magnet (17), fourth pole shoe (8), right sleeve (10), right bearing (11), and end cap (13) are installed in series. Then, bolts (12) are used to tighten them. The shaft (1) is installed in place by passing through the left bearing (3) and the right bearing (11). Magnetic liquid (18) is injected into the gap between the shaft (1) and each pole shoe. The left permanent magnet (14) and the right permanent magnet (17) adopt a ring structure, are axially magnetized, and are made of neodymium iron boron. The electro-permanent magnet (15) adopts a ring structure, is axially magnetized, and is made of AlNiCo. The edge of the excitation coil (16) maintains a certain distance from the adjacent pole shoes on both sides; When the left permanent magnet (14), the electro-permanent magnet (15) and the right permanent magnet (17) are installed, the magnets on both sides of the pole shoe have the same polarity; When the magnetic liquid sealing device is in a low-temperature environment, it exceeds the starting torque requirement during normal startup. At this time, the excitation coil (16) passes an electric pulse, and the magnetic poles of the electro-permanent magnet (15) change. The magnetic pole distribution of the permanent magnet and the electro-permanent magnet (15) becomes NSNSNS. Only the magnetic liquid (18) at the pole teeth of the first pole shoe (5) and the fourth pole shoe (8) plays a sealing role. The starting torque required is minimal, and the starting requirement is met. When the seal fails or the pressure is maintained during operation, an electric pulse can be passed to the excitation coil (16) again. The magnetic poles of the electro-permanent magnet (15) change. The magnetic pole distribution of the permanent magnet and the electro-permanent magnet (15) becomes NSSNNS. The magnetic liquid (18) at the four pole shoes can play a sealing role, and the pressure resistance increases.

2. The series-connected electro-permanent magnet magnetic liquid sealing device according to claim 1, characterized in that, Each pole shoe has 1-14 pole teeth.

3. The series-connected electro-permanent magnet magnetic liquid sealing device according to claim 1, characterized in that, The sealing gap between the shaft (1) and each pole shoe is 0.05-0.15mm.

4. The series-connected electro-permanent magnet magnetic liquid sealing device according to claim 1, characterized in that, The electro-permanent magnet (15) and the excitation coil (16) are located in the middle of the sealing device or on the side close to the outside air.

5. A series-connected electro-permanent magnet magnetic liquid sealing device according to claim 1, characterized in that, The left permanent magnet (14) and the right permanent magnet (17) are not fully magnetized.

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