Online monitoring of mudline position using magnetorheological fluid damper

Abstract

The invention provides a magnetorheological fluid damper for online monitoring of the mud line position. The damper includes an annular magnetic float and a plurality of reed switches. The magnetic float includes an annular permanent magnet and a composite coating structure wrapped around the outside of the annular permanent magnet. The magnetic float is arranged in the upper cavity. The magnetic float is sleeved on the piston rod. The density of the magnetic float is greater than the density of the upper clear liquid and less than the density of the lower mixed liquid. The online monitoring device performs online monitoring of the magnetorheological fluid sedimentation process above the piston, and the float is not obstructed when tracking the change in mud line height. The height position of the magnetic float is displayed by monitoring the conduction state of the reed switch, thereby achieving the purpose of real-time monitoring of the magnetorheological fluid sedimentation.

Description

Technical Field

[0001] The present invention relates to the technical field of equipment detection, and in particular to a magnetorheological fluid damper for online monitoring of mudline position. Background Art

[0002] Magnetorheological fluid (MRF) is a suspension system composed of micron-sized soft magnetic particles with high magnetic permeability and low magnetic hysteresis, mixed with a non-magnetic carrier liquid. Due to the density difference between the MRF dispersed phase and the carrier liquid, sedimentation is inevitable when the fluid is left standing.

[0003] Currently, the main methods for measuring the sedimentation characteristics of magnetorheological fluids (MRFs) include visual observation, thermal conductivity, inductance, and potential analysis. The visual method analyzes MRF sedimentation by observing the changes in the mudline, but is not suitable for observing MRF sedimentation in non-transparent containers. The thermal conductivity method uses a temperature probe mounted at the bottom of the MRF sample column to measure the thermal conductivity of the MRF at a fixed position. Because thermal conductivity is concentration-dependent, its conversion to MRF sedimentation monitoring is limited by the thermal stability of the sample. The inductance method uses a vertically moving, scanning self-sensing sensor to track the descending mudline to assess MRF sedimentation, but is not suitable for monitoring MRF sedimentation in ferromagnetic containers.

[0004] In summary, the existing technology can only monitor magnetorheological fluid samples in a non-service state, which belongs to non-in-situ monitoring and cannot meet the requirements of online monitoring when the damper is in working condition. Summary of the Invention

[0005] The purpose of the present invention is to provide a magnetorheological fluid damper for online monitoring of mudline position, so as to solve the problems existing in the prior art.

[0006] The technical solution adopted to achieve the purpose of the present invention is as follows: a magnetorheological fluid damper for online monitoring of mudline position includes a working cylinder, a piston assembly, magnetorheological fluid and a magnetorheological fluid sedimentation online monitoring device.

[0007] The working cylinder is arranged vertically. Magnetorheological fluid is contained within the working cylinder. The piston assembly includes a piston rod and a piston. The piston is mounted on the end of the piston rod. The piston assembly is inserted into the working cylinder and extends into the magnetorheological fluid. The piston divides the inner cavity of the working cylinder into an upper cavity and a lower cavity. When the damper is not in operation, the sedimentation process of the magnetorheological fluid in the upper and lower cavities is independent of each other.

[0008] The magnetorheological fluid sedimentation online monitoring device includes an annular magnetic float and several reed switches. The magnetic float comprises an annular permanent magnet and a composite coating structure surrounding the annular permanent magnet. The magnetic float is disposed in the upper chamber. The magnetic float is sleeved onto the piston rod. The several reed switches are disposed on the outer wall of the working cylinder. The reed switches are spaced evenly apart vertically.

[0009] When the damper is not in operation, the magnetorheological fluid settles. As the settling process progresses, the magnetorheological fluid produces an upper layer of clear liquid and a lower layer of mixed liquid. The boundary between the upper layer of clear liquid and the lower layer of mixed liquid is marked as the mud line. The density of the magnetic float is greater than the density of the upper layer of clear liquid and less than the density of the lower layer of mixed liquid. The magnetic float floats along the piston rod as the position of the mud line changes. The magnetic float drives the reed switch at the corresponding height position to attract and change the impedance in the circuit, and converts it into an electrical signal output to track the height change of the mud line during the sedimentation process. When the damper is in operation, the magnetorheological fluid redisperses and the mud line disappears. At this time, the magnetic float is at the highest liquid level of the magnetorheological fluid.

[0010] Furthermore, the composite coating layer structure is made of PA or PP material.

[0011] Furthermore, the plurality of reed switches are packaged as a thin strip circuit board, which is fixed to the outer wall of the working cylinder.

[0012] Furthermore, the working cylinder is made of non-magnetic material.

[0013] Furthermore, the outer end of the piston assembly is connected to the main body of the controlled object or a receiving carrier.

[0014] The technical benefits of this invention are undeniable: The sedimentation of the magnetorheological fluid above the piston is monitored online, allowing the float to track changes in the mudline height without obstruction. By monitoring the conduction state of the reed switch, the height of the magnetic float is displayed, achieving real-time monitoring of the magnetorheological fluid sedimentation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the working principle diagram of the magnetorheological fluid sedimentation online monitoring device;

[0016] Figure 2 Schematic diagram of the magnetic float structure;

[0017] Figure 3 This is the reed switch installation method;

[0018] Figure 4 This is the electrical schematic diagram.

[0019] In the figure: a magnetic float 1, an annular permanent magnet 101, a composite coating structure 102, a reed switch 2, a piston 3, and a piston rod 4. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the following examples, but it should not be understood that the scope of the present invention is limited to the following examples. Without departing from the above technical ideas of the present invention, various substitutions and modifications can be made according to common technical knowledge and customary means in the art, and all should be included in the scope of protection of the present invention.

[0021] Example 1:

[0022] Magnetorheological dampers are generally used in conjunction with elastic elements. Figure 1 , this embodiment provides a magnetorheological fluid damper for online monitoring of mudline position, including a working cylinder, a piston assembly, magnetorheological fluid and a magnetorheological fluid sedimentation online monitoring device.

[0023] The working cylinder is arranged vertically. Magnetorheological fluid is contained in the working cylinder. The piston assembly includes a piston rod 4 and a piston 3. The piston 3 is installed at the end of the piston rod 4. The piston assembly is inserted into the working cylinder and extends into the magnetorheological fluid. The piston 3 divides the inner cavity of the working cylinder into an upper cavity and a lower cavity. When the damper is in a non-working state (such as when the vehicle is stopped and the suspension magnetorheological damper enters a static state), the magnetorheological fluid in the upper cavity and the lower cavity will begin their own independent sedimentation processes. Since the sedimentation processes of the magnetorheological fluid in the upper cavity and the lower cavity are independent of each other, monitoring the sedimentation process of any part can reflect the sedimentation state of the magnetorheological fluid.

[0024] The magnetorheological fluid sedimentation online monitoring device includes an annular magnetic float 1 and a plurality of reed switches 2. Figure 2 The magnetic float 1 includes an annular permanent magnet 101 and a composite coating structure 102 wrapped around the outside of the annular permanent magnet 101. The magnetic float 1 is arranged in the upper cavity. The magnetic float 1 is sleeved on the piston rod 4. The magnetic float is designed to be annular and loosely sleeved on the piston rod 4. The outer diameter of the float forms a gap fit with the inner diameter of the cylinder, so that the float is not hindered when tracking the change in mud line height. In view of the fact that the float may rotate around the piston rod 4, in order to keep it always within the magnetic range of the magnetic float, the permanent magnet in the magnetic float can be considered to be axially or radially magnetized.

[0025] The plurality of reed switches 2 are arranged on the outer wall of the working cylinder. The plurality of reed switches 2 are arranged at equal intervals along the vertical direction. In order to improve the recognition and resolution of the mud line position, it is appropriate to use a small-scale reed switch.

[0026] When the damper is not in operation, the magnetorheological fluid settles. As the settling process progresses, the magnetorheological fluid produces an upper layer of clear liquid and a lower layer of mixed liquid. The boundary between the upper layer of clear liquid and the lower layer of mixed liquid is marked as the mud line. The density of the magnetic float 1 is greater than the density of the upper layer of clear liquid and less than the density of the lower layer of mixed liquid. The magnetic float 1 floats along the piston rod 4 as the position of the mud line changes. The magnetic float 1 drives the reed switch 2 at the corresponding height position to attract and change the impedance in the circuit, which is converted into an electrical signal output to track the height change of the mud line during the settling process. Figure 4By setting the resistance of each circuit, the voltage corresponding to each reed switch is set. Ultimately, the movement of the mudline is monitored by monitoring the changes in the output voltage. The value of resistor R is determined by the power supply VCC and the maximum on-off current of the reed switch. The maximum on-off current represents the maximum current that can pass through the contacts. If the contact current exceeds this value, the service life and reliability of the reed switch will be reduced.

[0027] When the damper is in working state, the magnetorheological fluid is redispersed and the mud line disappears. At this time, the magnetic float 1 is at the highest liquid level of the magnetorheological fluid.

[0028] Example 2:

[0029] The main structure of this embodiment is the same as that of embodiment 1, wherein, in order to achieve the characteristic average density of the float, the composite coating structure 102 is made of PA or PP material. After wrapping, the adsorption effect of the magnetic float on the dispersed phase of the magnetorheological fluid can be reduced. In order for the magnetic float to effectively track the mud line position, its average density needs to be specially set according to the density of the magnetorheological fluid dispersion medium. The average density of the float is determined by the density of the dispersion medium used in the magnetorheological fluid. When the dispersion medium is silicone oil and the density is 0.9g / cm 3 The recommended average density is 1.0-1.2g / cm 3 .

[0030] Example 3:

[0031] This embodiment shares the same primary structure as Embodiments 1 or 2. However, since the magnetorheological fluid damper for online mudline position monitoring is installed within a magnetorheological damper having a movable piston 3, the mudline disappears when the damper is operating, allowing the magnetic float to float freely and unimpeded. This embodiment is suitable for situations where, when the damper is not operating, piston 3 is located in the middle or bottom of the cylinder, i.e., the upper chamber has a certain height.

[0032] Example 4:

[0033] A reed switch, also known as a tongue or reed switch, is a special magnetically sensitive switch. It typically consists of two metal reed contacts made of a soft magnetic material that open when magnetized. These reed contacts are enclosed in a glass tube filled with an inert gas (such as nitrogen or helium) or a vacuum. The ends of the parallel reeds within the tube overlap, with a gap or contact, to form the normally open or normally closed contacts of the switch. When a magnet approaches it, the two nodes of the reed switch are attracted together, completing the circuit. Compared to conventional mechanical switches, reed switches offer simpler structure, smaller size, higher speed, and longer operating life. Compared to electronic switches, they also offer greater resistance to load shocks and high reliability.

[0034] See also Figure 3The main structure of this embodiment is the same as any of Embodiments 1, 2, or 3. Since the reed switches themselves are relatively fragile, several reed switches 2 are packaged as thin strip circuit boards. These thin strip circuit boards are affixed to the outer wall of the working cylinder. Their height should be greater than the maximum change in mudline height during sedimentation of the magnetorheological fluid. During installation, the topmost reed switch is aligned with the free surface of the magnetorheological fluid within the damper. The ability to resolve the mudline position depends on the vertical spacing between the reed switches. Other reed switch arrangements are also possible.

[0035] Example 5:

[0036] The main structure of this embodiment is the same as any one of embodiments 1, 2, 3 or 4, wherein the outer end of the piston assembly is connected to the main body of the controlled object or the receiving carrier. Due to the shielding effect of ferromagnetic materials on the magnetic field of the magnetic float, the working cylinder is made of non-magnetic material.

Claims

1. Magnetorheological fluid damper for online monitoring of mudline position, characterized by: It includes a working cylinder, a piston assembly, a magnetorheological fluid and a magnetorheological fluid sedimentation online monitoring device; The working cylinder is arranged vertically; the working cylinder contains magnetorheological fluid; the piston assembly comprises a piston (3) and a piston rod (4); the piston (3) is mounted on the end of the piston rod (4); the piston assembly is inserted into the working cylinder and extends into the magnetorheological fluid; the piston (3) divides the inner cavity of the working cylinder into an upper cavity and a lower cavity; when the damper is in a non-operating state, the sedimentation processes of the magnetorheological fluid in the upper cavity and the lower cavity are independent of each other; The magnetorheological fluid sedimentation online monitoring device comprises an annular magnetic float (1) and a plurality of reed switches (2); the magnetic float (1) comprises an annular permanent magnet (101) and a composite coating structure (102) wrapped around the outside of the annular permanent magnet (101); the magnetic float (1) is arranged in an upper cavity; the magnetic float (1) is sleeved on a piston rod (4); the plurality of reed switches (2) are arranged on the outer wall of a working cylinder; the plurality of reed switches (2) are arranged at equal intervals in a vertical direction; When the damper is not in operation, the magnetorheological fluid settles; As the sedimentation process progresses, the magnetorheological fluid produces an upper layer of clear liquid and a lower layer of mixed liquid; the boundary line between the upper layer of clear liquid and the lower layer of mixed liquid is marked as a mud line; the density of the magnetic float (1) is greater than the density of the upper layer of clear liquid and less than the density of the lower layer of mixed liquid; the magnetic float (1) floats along the piston rod (4) as the position of the mud line changes; the magnetic float (1) drives the reed switch (2) at the corresponding height position to attract and change the impedance in the circuit, and converts it into an electrical signal output to achieve tracking of the height change of the mud line during the sedimentation process; when the damper is in working state, the magnetorheological fluid is redispersed and the mud line disappears, and at this time the magnetic float (1) is at the highest liquid level position of the magnetorheological fluid.

2. The magnetorheological fluid damper for online monitoring of mudline position according to claim 1, characterized in that: The composite coating layer structure (102) is made of PA or PP material.

3. The magnetorheological fluid damper for online monitoring of mudline position according to claim 1, characterized in that: A plurality of reed switches (2) are packaged as a thin strip circuit board; the thin strip circuit board is fixed to the outer wall of the working cylinder.

4. The magnetorheological fluid damper for online monitoring of mudline position according to claim 1, characterized in that: The working cylinder is made of non-magnetic material.

5. The magnetorheological fluid damper for online monitoring of mudline position according to claim 1, characterized in that: The outer end of the piston assembly is connected to the main body of the controlled object or a receiving carrier.

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