272 results about "Magnetic liquids" patented technology

The invention discloses a silicone oil-based magnetic liquid with low volatility and radiation resistance as well as a preparation method and application thereof, and relates to the technical field of nuclear reactors. The silicone oil-based magnetic liquid comprises nano magnetic particles, a modifier, a surfactant and a base carrier liquid, the nano magnetic particles are changed from water solubility to oil solubility under the action of the modifier, the surface of the nano magnetic particles modified by the modifier is coated with the surfactant, and the base carrier liquid comprises polymethylphenyl siloxane fluid. The silicone oil-based magnetic liquid prepared by the invention has the advantages of chemical inertness, thermal stability, oxidation resistance, low vapor pressure, low ignition point and the like of conventional silicone oil, also has better high temperature resistance, radiation resistance, lubricating property and dissolving property, has the working temperature of-50 DEG C to 250 DEG C, and is excellent low-volatility and radiation-resistant silicone oil-based magnetic liquid.

The invention relates to the technical field of high-voltage commutation, and discloses a control method and system for a composite LC filter of a high-voltage converter station, and a storage medium. According to the method, on the basis of staggered solid / liquid-filled dielectric plates and series hollow inductors in a sealed oil tank, by obtaining a capacitance / inductance adjusting instruction, the filling and pumping volume and speed of insulating liquid and magnetic liquid are controlled according to the absolute value of an adjusting value, and continuous and accurate adjustment of the filtering frequency and reactive power is achieved. The method comprises multiple optimization: monitoring high fluctuation of liquid, synchronously filling, pumping and radiating, balancing efficiency and energy consumption according to an adjusting frequency adaptive circulation speed, and performing reverse linkage cooperative adjustment on a dielectric medium pump and a magnetic liquid pump; and magnetic liquid leakage and insulation abnormity are treated in stages, so that operation is guaranteed. The method solves a traditional adjustment dead zone, does not need a power electronic device, is low in cost, is small in loss, is adaptive to outdoors, and improves the electric energy quality and equipment safety of a converter station.

The low-resistance carrier roller device comprises a carrier roller, a bearing seat and a first sealing assembly, the carrier roller comprises a roller and a rotating shaft, the roller is arranged on the rotating shaft in a penetrating mode, the bearing seat comprises a shell with an opening and a bearing arranged in the shell, one end of the rotating shaft penetrates through the opening and is arranged on the bearing in a penetrating mode, and the other end of the rotating shaft is connected with the first sealing assembly. The first sealing assembly is arranged in the shell and arranged on the rotating shaft in a penetrating mode, the inner circumferential face of the first sealing assembly and the outer circumferential face of the rotating shaft are arranged at intervals in the radial direction of the rotating shaft and are filled with magnetic liquid, and the first sealing assembly is located on the side, close to the opening, of the bearing. The first sealing assembly seals the opening with the magnetic liquid. The low-resistance carrier roller device has the advantages of being low in resistance, small in leakage, long in service life and the like.

The present invention proposes a three-core hollow optical fiber magnetic field and temperature sensor based on magnetic fluid filling, with a three-core optical fiber sensing module as a sensitive element, the three-core optical fiber sensing module includes an outer cladding, an inner cladding, a first hollow core, a second hollow core, and a third hollow core, the three hollow cores are arranged at 120 degrees in space, the magnetic liquid and the glycerol liquid are respectively filled into the first hollow core and the third hollow core to obtain two liquid waveguides, the second hollow core is not filled, the detection light output by the two liquid waveguides interferes with the reference light output by the second hollow core, two interference spectra are obtained by a spectrum analyzer, and the magnetic field sensitivity characteristics of the magnetic fluid and the temperature sensitivity characteristics of glycerol are used to detect the drift of the interference image to infer the changes in the magnetic field and temperature. The optical fiber sensor not only achieves the purpose of simultaneous measurement of the dual parameters of magnetic field and temperature, but also has temperature compensation capability, thereby improving the accuracy of magnetic field measurement.

The invention relates to a pressure and temperature multifunctional sensor for energy collection and a manufacturing method thereof, the pressure and temperature multifunctional sensor adopts a double-layer composite structure: an upper wire coil layer is composed of a liquid metal coil embedded in a PDMS substrate, silver paint and a wire connected with the silver paint, and a lower magnetic fiber network layer is formed by weaving magnetic liquid crystal elastomer LCE composite fibers; the two are structurally integrated through a bonding layer; a coil conductive loop in the upper wire coil layer is formed on the surface of the PDMS substrate through a direct-writing printing technology, and packaging protection is completed through secondary pouring of PDMS; the LCE composite fiber takes an LCE hollow fiber tube as an external carrier, magnetorheological fluid is filled in the LCE composite fiber to serve as a magnetic medium, and two ends of the LCE composite fiber are sealed and packaged by adopting a compound of neodymium iron boron magnetic particles and PDMS (Polydimethylsiloxane). The sensor provided by the invention not only can realize pressure and temperature sensing, but also can be used as an energy collection device, provides a new solution for sustainable development of wearable equipment and sensors, and has a wide application prospect.

The invention discloses a multi-magnetic-source comb-shaped water tank magnetic liquid sealing device, and belongs to the field of mechanical engineering sealing. A first pole shoe, a second pole shoe, a third pole shoe and a fourth pole shoe which are provided with annular comb-shaped tooth grooves are alternately connected with a first permanent magnet, a second permanent magnet and a third permanent magnet in series, wherein the first permanent magnet, the second permanent magnet and the third permanent magnet are arranged in a manner that N-S-S-N-N-S magnetic sources are arranged in sequence or N-S-N-S-N-S-S-S-S-S magnetic sources are arranged in an inverted manner, and the multi-magnetic-source comb-shaped water tank sealing assembly is formed. Each pole shoe is provided with an annular cooling water tank, and spiral fins are machined on the bottom face and the side face of each cooling water tank, so that the effective heat exchange area in magnetic liquid sealing can be increased, convective heat transfer of cooling fluid is enhanced, the heat dissipation capacity is enhanced, the stable temperature of the magnetic liquid is kept, the sealing pressure resistance is improved, and the service life is prolonged. The installation mode that the multiple magnetic sources are sequentially arranged can compensate the weakening effect of the water tank on the magnetic field through magnetic field superposition, the magnetic field intensity difference value of the pole teeth is increased, and the sealing and pressure resisting capacity of the magnetic liquid is further enhanced.

The invention discloses a low-viscosity high-stability perfluoropolyether-based magnetic liquid and a preparation method thereof, and relates to the technical field of magnetic material preparation, and the preparation method comprises the following steps: preparing composite nano magnetic particles of ferroferric oxide and carbon nanotubes by adopting a chemical in-situ coprecipitation method; coating the composite nano magnetic particles with a perfluoropolyether surfactant; the composite nano magnetic particles are dispersed into the perfluoropolyether oil-based carrier liquid, and the solid content of the composite nano magnetic particles accounts for 5 wt%-20 wt%. Ferroferric oxide and carbon nano tube composite nano magnetic particles are obtained through a chemical precipitation method, the particles are stably dispersed in perfluoropolyether-based carrier liquid under the modification effect of a surfactant, and under the condition of low solid content, the dispersion stability and magnetic field stability of the magnetic liquid are greatly improved; the problem of overheating caused by the fact that high-viscosity magnetic liquid is used for high-rotating-speed sealing is greatly solved.

The invention relates to an automatic flaw detection, comparison and recognition machine tool for steering knuckles, which comprises a case, a horizontal partition plate fixedly connected in the case, and a clamping mechanism moving in the front-back direction, a magnetizing mechanism moving in the left-right direction, a recognition assembly, a spraying assembly and a purging assembly arranged in an inner cavity of the case above the partition plate, the magnetization mechanism and the recognition assembly are both located on the right side of the clamping mechanism and distributed front and back. The steering knuckle can be firmly fixed through the clamping mechanism, magnetization and demagnetization of the steering knuckle are achieved through two electromagnets of the magnetization mechanism, magnetic liquid is sprayed to the magnetized steering knuckle through the spraying assembly, the steering knuckle is photographed through the recognition assembly, and defects are automatically compared and recognized. And finally, the magnetic liquid on the surface of the steering knuckle is purged through the purging assembly. The machine tool is specially designed for steering knuckle flaw detection, full-automatic operation can be achieved in the process, use is more convenient, steering knuckle flaw detection precision is higher, and flaw detection efficiency is greatly improved.

Disclosed in the present invention is a microfluidic antenna with a reconfigurable frequency and directivity pattern. The microfluidic reconfigurable antenna consists of six parts, which are a metal floor, a metal radiation patch, a top reflector, a middle dielectric substrate, a coaxial feeder line penetrating the dielectric substrate, and an annular microfluidic channel packaged with a magnetic liquid metal column, respectively. Different modes can be excited by means of manipulating the length of the magnetic liquid metal column in the microfluidic channel, thus realizing the switching between radiation frequency bands; an antenna directivity pattern is reconfigured by means of manipulating the position of the magnetic liquid metal column; the microfluidic antenna involves main beam switching in a total of ten azimuthal planes within three bands of 5.98-6.10 GHz, 6.08-6.23 GHz and 6.85-7.47 GHz, and the maximum gain values in the states of the three bands are 8.5 dB, 7.4 dB and 8.1 dB, respectively; and the front-to-back ratios are 13 dB, 17 dB and 16 dB, respectively. The present invention has the characteristics of a simple structure, easy integration, a good performance, no introduction of extra distortion, low noise, a high-power operation capability and flexible application.

The invention provides a magnetic liquid drop and particle collision measurement experiment device based on a computer vision technology, and belongs to the field of particle collision characteristic detection. The problems that in the collision measurement process of the magnetic liquid drops and the particles, external field regulation and control are lacked, and personal errors exist in the image analysis process are solved. The device comprises a magnetic control device, a particle fixing device, a liquid drop emitting device and a data acquisition and processing device, the magnetic control device controls the magnetic field intensity by controlling the magnitude of voltage and current input by a direct-current power supply, and the magnetic field direction is changed by adjusting a magnetic field generator; the particle fixing device fixes particles; the liquid drop emitting device emits magnetic liquid drops; a high-speed camera and a data acquisition instrument in the data acquisition and processing device can acquire and record experimental data and feed back the experimental data to a data processing unit, and a computer vision technology is utilized to carry out dynamic capture and image recognition on the spreading process of the magnetic liquid drops on the surfaces of the particles. The collision process can be accurately controlled, and the collision process is dynamically captured through the computer vision technology.

The invention discloses a high-stability magnetic liquid and a preparation method thereof, and belongs to the field of magnetic fluid nano functional materials related to ships. The magnetic liquid comprises a metal-doped iron oxide nano-particle core, a double-layer surface modification layer composed of oleic acid and a silane coupling agent, and a composite carrier liquid formed by compounding poly-alpha olefin synthetic oil and perfluoropolyether and adding nano-diamond. The preparation method comprises the following steps: firstly, coprecipitating and calcining to obtain metal-doped iron oxide nanoparticles, then carrying out double-layer coating modification, and finally carrying out mixed ball milling, ultrasonic treatment and magnetic separation purification on the metal-doped iron oxide nanoparticles and the composite carrier liquid. The saturation magnetization intensity of the magnetic liquid reaches 92-95 emu / g, the magnetic liquid can work for a long time under the high-temperature working condition, the heat conductivity coefficient is increased by 2-3 times, and the redispersibility is excellent. The problems that a traditional magnetic fluid is low in magnetic performance, prone to failure at high temperature, poor in dispersion stability and the like are solved, and the magnetic fluid is suitable for aerospace, high-end manufacturing, ship propulsion and other extreme scenes.

The invention relates to the technical field of miniature medical robots, and discloses a magnetic liquid metal-based soft drug-loaded capsule robot, which comprises a soft capsule robot main body, a soft capsule robot cover and a degradable sealing sleeve, the soft capsule soft robot main body comprises a bottom fan-shaped magnetic liquid metal storage cabin, a left fan-shaped medicine storage cabin, a left rectangular medicine release port, a right fan-shaped medicine storage cabin and a right rectangular medicine release port. According to the soft drug-loaded capsule robot based on the magnetic liquid metal and the preparation and driving method of the soft drug-loaded capsule robot, a Helmholtz coil is used for generating a clockwise rotating composite magnetic field on a YZ plane, and anticlockwise rolling of a capsule is achieved through magnetic response of the magnetic liquid metal; the problem of limited energy supply of the micro-robot is solved through driving of an external magnetic field, and movement in any direction and accurate positioning are supported; the gelatin sealing sleeve is melted through external laser irradiation, and instant release of the medicine is achieved (suitable for emergency treatment).

The invention relates to a magnetic liquid sealing valve, belongs to the technical field of valves, and solves the technical problem that the sealing performance of a valve in the prior art is relatively weak. The valve body is provided with a valve core and a shell; the sealing structure is provided with a permanent magnet component, a magnetic conducting component and magnetic liquid; the magnetic conductive component is provided with a magnetic conductive ring; the inner ring of the magnetic conducting ring protrudes towards the sealing side in the axis direction of the inner ring; and an included angle a is formed between the inner ring surface N1 of the magnetic conducting ring and the axis M of the valve core. The protruding structure and a certain included angle of the magnetic conducting ring enable magnetic field lines to be more concentrated and ordered, it is ensured that magnetic liquid is arranged along the magnetic field lines and concentrated on the sealing side, and a thicker and more uniform liquid sealing ring is formed. The design of the magnetic conducting ring ensures that more magnetic liquid is guided to the sealing side, the thickness and the uniformity of the liquid sealing ring are improved, and the sealing effect is enhanced.

The utility model relates to the technical field of liquid level controllers, and discloses a motion-type magnetic liquid level controller, comprising a tube body, wherein the tube body is fixedly connected with a fixed direction plate, the fixed direction plate is slidably connected with an outer sleeve, the outer sleeve is fixedly connected with a connecting pipe, a float is fixedly installed at one end of the connecting pipe, a magnet is arranged on one side inside the outer sleeve, and a cement counterweight is arranged on the other side inside the outer sleeve. Through the arrangement of the float, the controller can push the outer sleeve to move by relying on the reaction thrust force generated on the float when the water level rises, so that the magnet inside the controller controls the opening and closing of the closing control valve of the movable rod and the copper contact, thereby greatly improving the liquid level measurement accuracy of the controller.

The utility model discloses a magnetic field liquid pressure difference sealing performance-rheological property synchronous measurement system which comprises a rheometer main body, a sealing rotor structure, a pneumatic pressurizing device, a temperature control and measurement device and a computer measurement and control device, the pneumatic pressurizing device comprises a constant pressure pump and a gas storage bottle, and is connected with the sealing rotor structure through a vent hole in the shell; the temperature control and measurement device comprises a temperature controller and a temperature control execution module which is arranged on the side wall of an outer cylinder at one end, close to the magnetic liquid area, of the magnetic function unit; the computer measurement and control device is connected with the optical encoder, the pressure sensor, the temperature controller and the torque control type motor. The system can simulate and test the sealing effect and rheological property of the magnetic liquid in a static state and a dynamic state, explores the actual influence of the magnetic liquid on the sealing property when the magnetic liquid flows, and supports the rheological test under the condition of multi-field coupling of a flow field, a magnetic field and a temperature field.

The utility model discloses a novel side-mounted magnetic liquid level metering device, which relates to the technical field of liquid level metering devices and comprises a shell, a mounting mechanism is arranged on the shell, the shell is mounted on an external container through the mounting mechanism, a cavity is arranged in the shell, a liquid inlet pipe communicated with the cavity is fixed at the bottom of the shell, and a liquid outlet pipe communicated with the cavity is fixed at the bottom of the shell. According to the novel side-mounted magnetic liquid level metering device, after liquid level metering is completed, the end opening of the branch pipe is plugged through the sealing plug, the miniature air pump works and injects air into the cavity, the air pressure in the cavity rises, liquid in the cavity is pressed, the liquid in the cavity is separated from the branch pipe, the liquid in the cavity is separated from the branch pipe, and the liquid in the cavity is separated from the branch pipe. The liquid in the cavity flows back to the external container through the liquid inlet pipe under the action of air pressure, so that after measurement is completed, the liquid in the cavity can automatically flow back to the container to be measured, and the liquid is prevented from being wasted.

The present invention discloses a roller device and a belt conveyor. The roller device includes a rotating member, a mounting seat, a bearing, a sealing assembly, and a first permanent magnet. The bearing is provided with lubricating fluid and is disposed within a mounting cavity. One end of the rotating member extends through an opening and extends within the bearing. The sealing assembly includes a sealing unit and magnetic fluid. The sealing unit is disposed within the mounting seat and extends through the rotating member. The sealing unit is located on a side of the bearing adjacent to the opening, and the inner circumference of the sealing unit and the outer circumference of the rotating member are spaced apart in an inner-outer direction to form a first gap. The magnetic fluid fills the first gap. The first permanent magnet is disposed within the mounting cavity and located between the sealing assembly and the bearing. The first permanent magnet is connected to the sealing assembly. The first permanent magnet extends through the rotating member, and the inner circumference of the first permanent magnet and the outer circumference of the rotating member are spaced apart to form a second gap. The roller device of the present invention has the advantages of a simple structure and a long service life.

Provided is a device sealed with a magnetic liquid. The device includes: a rotary shaft, a tank body, a control unit, a first module, a second module, a magnetic liquid, and a pole-tooth. The first module and the second module are in the same configuration, each consists of an outer shell, a left pole-shoe, an electromagnet, a control wiring, a right pole-shoe, and a circlip. The device includes at least two modular structures; the control unit controls a first electromagnet and a second electromagnet to be magnetized to alternately bear a sealing role.

The self-supplemental magnetic liquid sealing device comprises a shell, a rotating shaft and at least one pole shoe. The rotating shaft is internally provided with at least one supplement groove for accommodating standby magnetic liquid. The rotating shaft is provided with an opening in communication with the supplement groove on the peripheral surface. The magnetic property of the multiple pole teeth of the pole shoe increases in a stepped manner in the direction away from the supplement groove. When the rotating shaft rotates, the magnetic liquid in the supplement groove flows out from the opening under the action of centrifugal force and is supplemented into the sealing gap of the multiple pole teeth under the attraction of the pole teeth. The device uses the magnetic field strength gradient to make the magnetic liquid fill the sealing gap. The magnetic liquid can be automatically supplemented or replaced without disassembling or opening the sealing device, thereby reducing the maintenance cost and downtime, effectively solving the problem of evaporation of the magnetic liquid, and improving the sealing reliability and service life of the magnetic liquid sealing device.

The magnetic liquid sealing device of the present application belongs to the field of mechanical engineering sealing. The device is composed of the following components: main shaft, magnetic liquid I, pole shoe ring I, shell, sealing ring I, pump I, container I, sealing ring II, electromagnet I, magnetic conducting sleeve, electromagnet II, pump II, container II, sealing ring III, pole shoe ring II, magnetic liquid II, sealing ring IV, end cover. The sealing device composed of these components is a module that can be used in stack. Two kinds of magnetic liquids are used alternately or simultaneously, which expands the applicable temperature range of the magnetic liquid sealing. The sealing device is modularized, and different types of magnetic liquids can be used in different modules to have different applicable temperature ranges. The magnetic liquid sealing can be used in a wide temperature range by connecting the modules in series. The electromagnet is used as the magnetic source, and according to different working temperatures, the state of each magnetic liquid sealing can be independently controlled through cooperation with the pump to prevent permanent failure of the magnetic liquid due to temperature problems.

The invention discloses a magnetic liquid sealing device capable of continuously supplementing magnetic liquid for an outer space, and relates to the technical field of sealing, the magnetic liquid sealing device comprises a rotating shaft, a shaft sleeve, a first pole shoe, a permanent magnet, a second pole shoe, a first oil seal and a second oil seal, the rotating shaft is sleeved with the shaft sleeve, and the first pole shoe, the permanent magnet and the second pole shoe are sequentially sleeved with the shaft sleeve; a first sealing gap and a second sealing gap are defined by the first pole shoe and the shaft sleeve and by the second pole shoe and the shaft sleeve respectively, the first oil seal and the second oil seal are arranged on the shaft sleeve corresponding to the first pole shoe and the second pole shoe respectively, and a liquid storage cavity used for storing magnetic liquid is formed between the first pole shoe and the second pole shoe. And the magnetic liquid in the liquid storage cavity is used for supplementing the first sealing gap and the second sealing gap. According to the magnetic liquid sealing device capable of continuously supplementing the magnetic liquid for the outer space, the oil storage structure is arranged, so that the sealing magnetic liquid is supplemented in time after being consumed, and the long-term reliability of magnetic liquid sealing under severe working conditions is guaranteed.

The invention provides a stiffness-adjustable acceleration sensor based on a magnetic liquid and a differential mutual inductance principle. The stiffness-adjustable acceleration sensor is used for solving the problems that an existing acceleration sensor is insufficient in sensitivity and fixed in equivalent stiffness, and measuring range and response are difficult to consider at the same time. The sensor takes a magnetic liquid suspended composite magnet working unit as a core, the working unit is composed of a middle iron core and permanent magnets on the two sides of the middle iron core, the whole working unit is immersed in magnetic liquid, stable suspension is achieved through second-order buoyancy of the magnetic liquid, and therefore mechanical friction is reduced, and the dynamic response performance is improved. A restoring force permanent magnet and an adjusting coil are arranged on the two sides of the sensor shell, and continuous adjustment of magnetic restoring force and equivalent stiffness is achieved by adjusting coil current. The first primary coil and the second primary coil are symmetrically arranged on the two axial sides of the iron core, the first secondary coil and the second secondary coil form a differential mutual inductance detection structure, displacement of the working unit causes mutual inductance change under the action of uniform acceleration, differential induction voltage is output, and high-sensitivity measurement of the uniform acceleration is achieved.

The utility model provides a magnetic liquid seasoning bottle, and particularly relates to the technical field of kitchen containers. The magnetic attraction type liquid seasoning bottle comprises a bottle body, an inner cover and an outer cover buckled on the top of the inner cover. A flow control air hole is formed in the center of the top of the inner cover; a liquid outlet nozzle is arranged on the side wall of the inner cover; a magnetic rubber mat is arranged on the outer side wall of one side of the bottle body; and the bottle body is detachably connected with the inner cover. The flow control air hole is formed in the top of the inner cap, the pressure in the bottle is changed by pressing the flow control air hole, and then the flow speed of liquid is changed; the area, corresponding to the through hole, of the top of the inner cover is sunken inwards and better fits the radian of fingers, and the blocking effect of the flow control air hole is better; in addition, through the magnetic rubber mat arranged on the outer side wall of the bottle body, the bottle can be attracted to a wall containing magnetic materials, the magnetic attraction function is strong, and storage is more convenient.

The utility model provides a kind of magnetic liquid coupling suspension mechanical pump with split end cap, it is characterized by, including: impeller assembly, end cap, shell and rotor assembly;The inner shell cavity is formed in the shell central area recess;The rotor assembly is installed in the inner shell cavity;The impeller assembly is connected with the rotor assembly;The end cap is including first split end cap and second split end cap formed along radial division, the first split end cap and the second split end cap are installed on the wheel shaft along radial direction.The utility model uses split end cap structure, so that it can realize the integrated forming of impeller assembly and rotor assembly, the structure avoids the structural interference problem caused by traditional end cap needing to be inserted from shaft end, so that impeller and rotor can be integrally inserted into shell interior for assembly, significantly reduce assembly complexity and requirement to machining precision.

The invention provides an annulus protection fluid and application thereof. The annulus protection fluid comprises a magnetic liquid, base grease, a solid filler and base oil. The annulus protection fluid comprises the magnetic liquid, the base grease, the solid filler and the base oil, and the formed fluid is a non-Newtonian fluid and is high in density and viscosity, so that the sealing performance of the fluid can be enhanced, a good plugging effect is achieved, the fluid has excellent corrosion resistance, and the service life of an oil casing can be prolonged.

The utility model discloses a pressure-resistant explosion-proof magnetic liquid level meter, which relates to the technical field of magnetic liquid level meters and comprises a clamping frame, a first measuring tube and a second measuring tube are respectively connected inside the clamping frame, an anti-overflow shell is connected to the top of the first measuring tube and the top of the second measuring tube, and a baffle tube is fixed below the inside of the anti-overflow shell. A pulley is connected to the upper portion in the anti-overflow shell, a high-temperature-resistant pull rope is connected to the top of the pulley, one end of the high-temperature-resistant pull rope is connected with a first hanging shell, a strong magnet is installed in the first hanging shell, and the other end of the high-temperature-resistant pull rope is connected with a second hanging shell. Through the arrangement of the first measuring tube, the second measuring tube, the first hanging shell, the strong magnet, the pulley, the high-temperature-resistant pull rope, the second hanging shell, the cavity and the balancing weight, a medium flows through the first measuring tube, and the second measuring tube measures the liquid level in a linkage mode, so that the strong magnet is separated from the high-temperature medium; the liquid level can be measured, and demagnetization of the strong magnet caused by high temperature is avoided; the use in a high-temperature environment is convenient.

This invention belongs to the field of oil and gas well exploration and development technology, specifically relating to a high-temperature sealing thread grease for oil casing and its preparation method and application. The thread grease comprises the following components in parts by weight: 33-58 parts base grease, 10-40 parts magnetic fluid, 1-5 parts polyethylene glycol, 5-10 parts phosphate ester, 4-10 parts fumed silica, 3-18 parts graphite, 1-5 parts nano-molybdenum powder, 1-5 parts nano-copper powder, 6-12 parts zinc powder, 10-30 parts lead powder, 5-10 parts alkylphenol resin, 5-15 parts acrylic resin, 5-15 parts polytetrafluoroethylene, 10-18 parts diisocyanate, 10-18 parts polyurethane, 10-12 parts tetraethylene glycol dimethacrylate, and 6-11 parts nitrile rubber. This invention ensures good lubricity while maintaining excellent sealing performance under high-temperature conditions.

The utility model discloses a self-cleaning type magnetic liquid level meter, which comprises two groups of external pipes, two groups of magnetic liquid level meters, two groups of magnetic liquid level meters and two groups of magnetic liquid level meters, the input end of the branch pipe is connected with a blow-off pipe of the liquid level meter, and two groups of output pipes of the branch pipe are respectively provided with an electromagnetic valve; the number of the switch electromagnetic valves is two, and the two switch electromagnetic valves are connected with the two connecting pipes of the liquid level meter respectively. The cleaning fluid tank comprises two groups of tank bodies, the two groups of external connection pipes are respectively connected with the output ends of the two groups of tank bodies, and pump machines are arranged between the external connection pipes and the tank bodies. According to the self-cleaning type magnetic liquid level meter, automatic operation of cleaning of the liquid level meter can be achieved. The manual operation of each valve and equipment is not needed, so that the labor cost is saved, the cleaning efficiency is improved, and meanwhile, the problems of poor cleaning effect and the like possibly caused by untimely or inaccurate manual operation are also reduced.