114results about How to "Helps fix" patented technology

The invention relates to a method for preparing biomass carbon based on waste crop straw. The method comprises the following steps of: (1) cutting the crop straw into straw particles, washing and drying; (2) loading the processed straw particles in a quartz tube of a carbonizing furnace and introducing an inert gas; (3) heating to 350 to 550 DE C from room temperature in an environment with inert gas flow rate of 100mL / min at the heating rate of 25 DEG C / min, maintaining for 1 to 3 minutes, stopping heating, and cooling to the room temperature to obtain solid; and (4) washing and drying the solid obtained in the step (3) to obtain the biomass carbon. The device of the invention is simple in operation, the raw material has low cost and is readily available, and the method is suitable for large-scale industrial production; and the biomass carbon prepared by the method has a high specific area, can be used as a soil modifying agent to improve the fertility of the soil and can also be used as a soil repairing agent to repair the polluted soil, and has good application prospect.

The invention discloses a method for remediating petroleum-contaminated soil through coupling a charcoal-loaded surface active agent and a microorganism plant. The method comprises the following stepsof S1, applying the charcoal-loaded surface active agent into a petroleum-contaminated soil surface layer, and then standing and ageing for 80 days; S2, after ageing the soil, watering the soil on the surface layer, enabling the water content to reach to 50 to 60 percent, adjusting a pH value of the soil to be 7 to 8, and then adding a petroleum degradation microbial inoculum into the soil, and fermenting; S3, after fermenting the soil, planting a plant prepared according to different quantitative proportions in the soil, and removing the whole plant after the plant is ripe; and S4, cyclically repeating S1 to S3 until detecting that the content of a petroleum pollutant in the petroleum-contaminated soil is less than or equal to 4.5g / kg. The method for remediating the petroleum-contaminated soil through coupling the charcoal-loaded surface active agent and the microorganism plant provided by the invention adopts an in-situ remediation technology, does not damage environment during theremediation process, cannot bring secondary pollution, is green and environmental-friendly, and realizes a composite remediating mode with a good green cycle remediating effect.

The invention discloses a water-based polyurethane dispersion for color fixation, and a preparation method and application thereof. The preparation method of the water-based polyurethane dispersion for color fixation comprises the following steps: 1, performing polymerization reaction on polyisocyanate, low polymer polylol and small molecule diol to obtain a polyurethane prepolymer; 2, performing crosslinking reaction on the polyurethane prepolymer and crosslinking agent in solvent to obtain crosslinked polyurethane; 3, performing dispersion and emulsification on the crosslinked polyurethane and deionized water to obtain a crosslinked polyurethane dispersion; 4, performing chain extension reaction on the crosslinked polyurethane dispersion and diamine to obtain chain-extended crosslinked polyurethane; and 5, performing termination reaction on the chain-extended crosslinked polyurethane and amino-terminated silane coupling agent to obtain the water-based polyurethane dispersion for color fixation. The preparation method disclosed by the invention is simple in process and low in energy consumption; and the prepared product has favorable film forming property and favorable color fixation property, and is suitable for industrial production.

The invention relates to a hydrophilic modification method of a high-flux PVDF porous membrane. The method comprises the following steps that PVDF powders, tannic acid and PVP are used as raw materials, firstly the PVDF porous membrane is prepared by adopting a phase inversion method, a metal ion solution is used as coagulation bath, by means of the strong complexing capacity of tannic acid with metal ions, a relatively stable molecular chain interpenetrating network structure is formed on the surface of the membrane and inside the membrane, thereby effectively complexing with tannic acid containing a plurality of hydrophilic groups, and the tannic acid has good complexation with PVP, so that more PVP is fixed, and finally a composite hydrophilic channel of tannic acid-PVP-metal ion is formed inside the membrane, so that a PVDF modified membrane with high flux and better hydrophilicity is prepared. The preparation method has the advantages of being wide in raw material source, low in preparation cost and simple in processing technology, and being beneficial for bulk production and marketization application and popularization, and meeting green environmental protection requirements.

The invention is applicable to the technical field of electronic devices and provides an intelligent power module manufacturing method. The method comprises the following steps: selecting a metal substrate, arranging an insulating layer and a circuit wiring on the metal substrate, installing circuit elements and pins on the circuit wiring and enabling the run of the pins to gradually incline upward; placing the metal substrate in a packaging mold, fixing the pins on a horizontal plane through a first fixing device and making the surface of the metal substrate incline relative to the horizontal plane; configuring a metal pressing block parallel to the horizontal plane and pressing the metal pressing block on the metal substrate to make the metal pressing block parallel to the horizontal plane; and injecting packaging material in the mold to seal the substrate. The metal substrate is accurately positioned in the packaging mold through the metal pressing block, holes can be prevented from being reserved in the packaging structure, and the packaging compactness is improved. After packaging is completed, the position of the metal pressing block in the packaging structure can be directly measured by using a simple measuring tool so that the position of the metal substrate in the packaging mold can be known and subsequent inspection is facilitated.

The invention relates to a hoisting mechanism. The hoisting mechanism comprises a pedestal; a screw rod is mounted at the left end of the pedestal; a weight table is arranged at the upper end of the screw rod; clamping plates are mounted at the two ends of the weight table; the clamping plates are mounted on the weight table through long screws; a threaded hole is formed in the side surface of the weight table; a handle is mounted inside the threaded hole and is provided with screw threads; a motor is mounted at the left end of the pedestal; a rotary seat is mounted at the right end of the pedestal; upright posts are arranged on the rotary seat; counter bores are formed in the pedestal. According to the hoisting mechanism disclosed by the invention, the arrangement of the weight table provided with the screw rod is conductive to lift of the weight table and is also conductive to regulation on the gravity center of the overall weight table; the arrangement of the long screw provided with the clamping plates is conductive to fixation of the weight block; the arrangement of the threaded hole provided with the handle is conductive to mounting and dismounting of the handle and is also conductive to rotation of the screw rod, so the weight table can be lifted and lowered; the hoisting mechanism is simple in structure, convenient to operate, economical and practical.

The invention provides an anti-aging impact-resistant modified wood-plastic composites (WPC) and a preparation method thereof. The wood-plastic composites are prepared from the following raw materials in parts by weight: 20-50 parts of polyolefin, 30-70 parts of enzymatic hydrolysis lignin modified vegetable fibers, 1-3.5 parts of polymerized rosin, 0.1-10 parts of an inorganic filler, 0.1-4 parts of an antioxidant, and 0.1-3 parts of an ultraviolet screening agent, wherein the enzymatic hydrolysis lignin modified vegetable fibers are prepared from enzymatic hydrolysis lignin and vegetable fibers through an anhydride reaction. According to the modified wood-plastic composites prepared by the invention, the affinity between the vegetable fibers and plastic is high, the dimensional stability of the composites is high, the rigidity and toughness are balanced, and ageing resistance is also improved at the same time; in the process of preparing the enzymatic hydrolysis lignin, a certain amount of ligninase is added, thus improving the impact resistance of the wood-plastic composites prepared from the enzymatic hydrolysis lignin modified vegetable fibres. Through the method of using the lignin to modify the vegetable fibers provided by the invention, lignin resources are fully used, waste is turned into treasure, and comprehensive utilization of the lignin resources is realized.

The invention discloses a hardness-controlled intelligent conduit for clinical intervention treatment. The conduit comprises an external conduit (1) and an internal conduit (3); a main body has the conventional conduit structure; and a metal enhancement layer (2) is arranged on an outer wall of the internal conduit (3); a structure containing a temperature sensitive high polymer layer also can be adopted, and a metal resistive layer (5) is arranged on the outer wall of the internal conduit (3); and a temperature sensitive high polymer layer (4) is coated on the external conduit (1). By applying a voltage or current signal on the metal enhancement layer (2) or the metal resistive layer (5), a local thermal effect is generated, the temperature of the temperature sensitive high polymer layer is raised, and Young modulus (also called hardness) is reduced. After an electric signal is cut off, the temperature of the polymer layer can be continuously reduced, while the hardness of the conduit is gradually increased to reach the initial hardness. The hardness-controlled intelligent conduit can greatly reduce the cost of frequently replacing the conduit, reduces the difficulty and risk of an operation, and shortens the operation time.

The invention discloses a preparation method and application of an electrochemical biosensor based on a three-dimensional nano-porous gold-modified boron-doped diamond electrode, and in particular relates to a preparation method of a boron-doped diamond electrode, a fixation method of acetylcholin esterase and application of acetylcholin esterase in organophosphorus pesticide residue detection for solving the technical problem that the boron doped diamond membrane electrode has low electrocatalytic activity, difficulty in surface reengineering and poor selectivity and sensitivity. The method comprises the following steps: 1, preparing three-dimensional nano-porous gold on the boron doped diamond electrode and modifying the boron doped diamond electrode; 2, fixing acetylcholin esterase on the three-dimensional nano-porous gold modified boron doped diamond electrode modified by the step 1 to construct the electrochemical biosensor. The electrochemical biosensor adopting the technical scheme is used for fixing the acetylcholin esterase and is used for electrochemical detection of organophosphorus pesticide residues, and the method can be used for increasing the specific surface, accelerating electron transfer, improving the electrocatalytic activity and improving the detection sensitivity.

The invention discloses a restoration method for petroleum polluted soil by coupling bio-charcoal loaded oxidation aid and microbe and plant. The restoration method includes the following steps: S1, the bio-charcoal loaded oxidation aid is put into the surface of petroleum-contaminated soil for 80 to 100 days when being placed and aged; S2, after the soil is aged, water is sprinkled on the surfacesoil to make the water content reach 50-60%, then the soil pH is adjusted to 7-8, then petroleum degrading bacteria is added to the soil for fermentation; S3, after soil is fermented, different proportions of shrub plants are planted in soil and after the plants are matured, the plants are removed as a whole; and S4, is the steps 1-3 are repeatedly carried out until the content of petroleum contaminants in the soil of petroleum contaminants is detected to no greater than 4.5 grams per kilogram. By adopting the in-situ restoration technology, the environment can not be damaged during the restoration process, secondary pollution can not be caused, green and environmentally friendly purpose is achieved, and a green, circular, composite restoration mode is achieved with good restoration effect.

The invention discloses a triphenylamine organic dye and a synthesis method thereof. The chemical structure of the triphenylamine organic dye is as shown in a general formula (1). In the formula (1),R<1> is selected from hydrogen or styryl, R<2> is selected from hydrogen or styryl, and the following structure is a quinoxaline derivative. The triphenylamine organic dye provided by the invention has a long conjugated D-pi-A structure, and meanwhile, molecules contain cyano groups and carboxyl, and the electrondrawing group is cyanoacetic acid. The triphenylamine organic dye can be used as a solar cell sensitizer, and has a good application prospect in dye-sensitized solar cells.

The invention discloses an electrochemical oxidation treatment device of a low-salt wastewater through micro-fluid reactor. An anode plate, an insulated membrane layer and a cathode plate are arrangedin the fluid direction; insulated pad layers are arranged on the outer sides of the anode plate and the cathode plate; shells are arranged on the outer sides of the insulated pad layers. The invention also discloses an electrochemical oxidation treatment method. An insulated membrane layer is only arranged between the anode plate and the cathode plate, so that a space of polar plates is greatly reduced, and the efficiency of an electrochemical reaction process is effectively improved; when a reaction device is used alone, a high action effect is achieved; according to different electrochemical oxidation processes, materials of the polar plates can be replaced; when the different polar plate materials are connected in series and the different electrochemical processes and electrochemical parameters are adopted, wastewater containing different types of pollutant substances are treated, so that the current density is increased to the maximum limit and the electrolysis time is shortened;electrochemical oxidation reaction on organic pollutants in the wastewater is directly carried out, so that secondary pollution is avoided.

The invention discloses a pipeline outer wall weld joint grinding device for building materials and building processing and relates to the technical field of building materials. The pipeline outer wall weld joint grinding device solves the problems that a currently used grinding device is complex in mechanical structure, relatively high in consumption cost and complex in manual operation steps andinconveniently carries out fast operation processing, the control over the grinding position of a weld joint is controlled mainly through electric appliance elements, and the currently used grindingdevice is inconveniently applied to the machining project of the small industry. The pipeline outer wall weld joint grinding device for building materials and building processing comprises a base. Thetop of the middle of the base is of a protruding structure, and two sets of vertical frames are fixedly arranged at the top of the protruding structure. A frame A and a frame B are fixedly arranged on the portion, located on the two sides of the vertical frames, at the top of the base through bolts correspondingly. By arranging gathering rings and locking sliding rods, sliding blocks can be movedaway to contract end blocks so as to be matched with clamping blocks to clamp pipelines, operation is easy, control is convenient, the balance is strong, and fixation of the pipelines is facilitated.

The invention relates to a building construction coating moisture-proof device. The building construction coating moisture-proof device comprises a base, a platform body is mounted on the base, a clamping wheel and support seats are mounted under the base, and the support seats are further located on both sides of the clamping wheel. A clamping head is installed at the left end of the platform body, a turntable is mounted at the right end of the platform body, a stand column is connected to the upper part of the turntable, a support is connected to the left side of the stand column, the support is further located at the lower end of the stand column, an L-shaped push rod is installed at the right end of the base, a handle is installed at the right end of the L-shaped push rod, a protectivecover is connected to the left end of the support, a rubber ring is mounted at the lower end of the protective cover, and a convex lug is mounted at the upper end of the stand column. According to the building construction coating moisture-proof device, realization of the position support and movement functions of the protective cover is facilitated by arranging the turntable, the support and thestand column, the quick installation of the base is facilitated by arranging the clamping wheel, fixation of a moisture-proof coating appliance is facilitated by setting the clamping head, the structure is simple, the operation is convenient, and economy and practicality are achieved.

The invention relates to a novel herringbone crawling ladder. The novel herringbone crawling ladder comprises a pedal, a first ladder assembly, a second ladder assembly, an angle adjusting plate A and an angle adjusting plate B, wherein three dowels are respectively fixed on the first ladder assembly and the second ladder assembly, and indexing grooves are formed in the angle adjusting plate A and the angle adjusting plate B. The novel herringbone crawling ladder has the advantages that the forming of the indexing grooves is conductive to the fixation of the first ladder assembly and the second ladder assembly, the arrangement of the angle adjusting plate A or the angle adjusting plate B are conductive to the small-angle adjustment of the first ladder assembly and the second ladder assembly, and the novel herringbone crawling ladder is simple in structure, convenient to operate, economic and practical.

The invention discloses a mechanical arm of a robot. The mechanical arm comprises a driving barrel, wherein two parallel connection blocks are arranged at the left end of the driving barrel, and connection holes are formed in the connection blocks, so that fixing of the left end of the barrel is facilitated; a touch handle is arranged at the right end of the driving barrel; the touch handle is made of a rubber material; the right end part of the touch handle is a contracted tip end; the section of the touch handle is rectangular; a negative pressure cavity is formed inside the touch handle; and a plurality of contraction slots are formed in the upper surface of the touch handle in an equal spacing manner. The mechanical arm is simple and reasonable in structure; the inside of the touch handle made of flexible plastic is hollowed, and then the tensile strengths of the upper and lower surfaces of the touch handle are set to be different, so that the touch handle can be bent in different extents by adjusting air pressure inside the touch handle; and therefore, a cup can be conveniently held. The mechanical arm of the robot is simpler in structure, thus contributing to reducing the cost; furthermore, the touch handle is made of a plastic material, thus facilitating injection molding; and the mechanical arm is high in machining efficiency and high in practicability, and the production efficiency of the device can be improved favorably.

It is intended to provide an easy-to-use, energy-saving and economical method of producing foamed resin particles having a high environmental compatibility by using an ether, which generates neither sulfur oxide nor sot in the course of disposal and incineration and enables considerable reduction in nitrogen oxide formation, and further using a resin which originates in a plant and contributes to the carbon dioxide fixation. Namely, a method of producing foamed P3HA resin particles comprising the step of feeding particles of a resin containing a copolymer, which is produced by a microorganism and has a repeating unit represented by the general formula (1) [-CHR-CH2-CO-O-] (wherein R represents an alkyl group represented by CnH2n+1 and n is an integer of from 1 to 15), and a foaming agent into an airtight container, and the step of heating the mixture until the resin particles become softening, then releasing one end of the airtight container and discharging the resin particles into an atmosphere with a pressure lower than the pressure in the airtight container to thereby foam the resin particles and give foamed particles. In this method of producing foamed P3HA resin particles, the foaming agent is at least one member selected from the group consisting of dimethyl ether, diethyl ether and methyl ethyl ether.

The invention discloses a portable drawing board bracket. The bracket comprises a base (1), a bracket body (2) hinged to the base (1), a duct (21) disposed in a middle of the bracket body (2) and a boss (22) arranged at the bottom of the bracket body (2), the duct (21) is provided with a moving support plate (3), the upper end of the bracket body (2) is hinged to an upper slide plate (4), the upper slide plate (4) is slidably connected with a lower sliding plate (5), the bottom of the lower slide plate (5) is hinged to a moving base (6), the moving base (6) is slidably connected with the base(1), and a fixing plate (7) is mounted on the lower end of the base (1). The portable drawing board bracket has a simple structure, is convenient to use, is convenient to carry, reduces the discomfortof drawing when used, saves physical strength, and improves drawing efficiency.

The invention discloses an automatic soilless culture production line, and belongs to the technical field of soilless culture. The automatic soilless culture production line is characterized by comprising a conveyor belt group, supporting frames and a plurality of soilless culture devices, wherein, each soilless culture device comprises a plurality of culture grooves; vegetable fixing discs are arranged on the inner walls of the culture grooves; two sliding grooves are formed in the inner wall of each culture groove, first stepping motors are arranged in the sliding grooves, and the first stepping motors are fixedly connected with the vegetable fixing discs; supporting transverse plates are fixedly connected to the outer sides of the two supporting frames correspondingly, and strip-shaped grooves are formed in the two supporting transverse plates correspondingly; second stepping motors and third stepping motors are installed in the strip-shaped grooves, the second stepping motors and the third stepping motors are connected with electric telescopic rods, rotating motors are arranged at the ends of the electric telescopic rods, and the rotating motors are connected with rotating parts; and a transverse part is fixedly connected between every two rotating parts, a plurality of sliding motors are arranged in the transverse parts, and the sliding motors are connected with picking blades. The automatic soilless culture production line is mainly used for automatically planting and picking vegetables, and the working efficiency and the automation degree are effectively improved.

The invention discloses a manufacturing method for a volute with a composite lining. The manufacturing method includes the steps reserving a gap in a cavity of a volute base body and arranging latticed reinforcing ribs; manufacturing the volute base body and forming an injection hole; designing a forming mold for forming the composite lining and a sealing mold and installing the forming mold and the sealing mold on the volute base body; adding short carbon fibers and macromolecular resin adhesive curing agents with macromolecular resin adhesives as a base body and then obtaining liquid composite material; injecting the liquid composite material into a forming cavity through the injection hole and carrying out pressure maintaining and solidifying; and disassembling the forming mold, blocking the injection hole and obtaining the volute with the composite lining. The manufacturing method is simple, the operation is convenient, the roughness of the cavity of the volute base body can be effectively lowered, the shape and the dimension of the cavity of the composite lining of the volute can be accurately controlled, and the operation of an impeller is reliable and efficient.

The invention discloses a volute structure provided with a composite lining. The volute structure provided with the composite lining comprises a volute base body and the composite lining used for reducing the surface roughness. Reinforcing ribs used for reinforcing the composite lining are arranged in an inner cavity of the volute base body, and a lattice shape is formed by the reinforcing ribs. The composite lining is arranged on the inner wall of the volute base body and fixedly connected with the inner wall provided with the reinforcing ribs. The volute structure provided with the composite lining is simple, reasonable in design and low in manufacturing difficulty; the roughness of the inner cavity of the volute base body can be effectively reduced through the composite lining, and the flowing air resistance of fluid during operation of an impeller is reduced; and the shape and dimension precision of the inner cavity of a formed volute provided with the composite lining is high, uniform gaps between blades and the volute can be accurately controlled, and the operating efficiency and reliability of a pump, a draught fan or a compressor can be obviously improved.

The invention discloses a leather tanning chromium-containing waste treatment method, which aims to solve the problems that hazardous wastes including chromium leather shavings and chromium mud can be generated during leather tanning, a small amount of trivalent chromium is converted into hexavalent chromium due to direct incineration of the chromium leather shavings, the toxicity of waste residues after combustion is increased, the treatment difficulty is increased, the nitrogen content of the chromium leather shavings is high, the nitric oxide content in combustion smoke is high, and the smoke treatment cost is high. The chromium leather shavings and chromium mud are treated through the four working stages of pretreatment, roasting, post-treatment and smoke treatment, the problem existing in landfill after direct incineration or direct landfill of the chromium leather shavings is solved, and recycling of waste resources is achieved,. The leather tanning chromium-containing waste treatment method has good environmental benefits and economic benefits.

The invention discloses an anchor rod construction device for building engineering. The device includes an anchor head, a first hollow rod, positioning fastening bodies, a second hollow rod, a backingplate, pressure plates, elastic control main bodies and a gate valve; the first hollow rod is connected to the second hollow rod through a sleeve; the middle position of the sleeve is provided with apour plug port; the pour plug port is provided with the gate valve; the gate valve is connected to the elastic control main bodies; one ends of the elastic control main bodies are connected to the pressure plates; the two sides of the sleeve are welded with the positioning fastening bodies; the end, away from the sleeve, of the first hollow rod is connected to the anchor head; the end, away fromthe sleeve, of the second hollow rod is connected to a slurry stopping plug; the outer end of the slurry stopping plug is connected to the backing plate; one end faces of the positioning fastening bodies are connected to the backing plate through elastic control connecting rods; the elastic control connecting rods pass through the backing plate; and the surfaces of the elastic control connecting rods are provided with elastic control switches. Through the arrangement of the sleeve and the positioning fastening bodies, the device can have functions of balancing a middle end and strengthening the bearing capacity of rock mass.

The invention belongs to the technical field of molecular sieve performance optimization, and particularly relates to a ZSM-5 molecular sieve and a mesoporous treatment method and application thereof. The microporous ZSM-5 molecular sieve is subjected to mesoporous treatment at normal temperature and normal pressure, so that the ion exchange capacity of the molecular sieve is greatly improved, pore channels suitable for silver ions to enter are 96% or above, the highest silver loading capacity can reach 43.36 WT% and is improved by about 2% compared with the silver loading capacity of a commonly-used silver-loaded NaY type zeolite molecular sieve, and the antibacterial effect is obviously improved; besides, after the antibacterial agent is added into a polymer modified material, the antibacterial effect of Ag is greatly exerted, and the problems of durability of a silver antibacterial material and odor of a polymer material are solved.

The invention discloses an integrated shielding curtain winding device, which comprises core iron, an inner pipe for winding a shielding curtain, and a spring ball and a torsion spring arranged in one end of the inner pipe, wherein the spring ball is formed by buckling a male spring ball and a female spring ball; a central hole coaxial to the core iron is preserved on the spring ball; one end of the core iron is connected with an outer seal cap, and the other end of the core iron is connected with a core iron fixing block; a compressed spring is also sleeved on the core iron and is arranged in the central hole preserved on the spring ball. According to the integrated shielding curtain winding device, three clamping tenons are arranged on the core iron and are used for fixing the core iron and relevant parts, the usage of partial parts is reduced, the product cost is reduced, the assembling is convenient, the whole stability is excellent, and meanwhile, the clearance between the shielding curtain and a side body can also be effectively improved.

The invention relates to the technical field of lock cylinder machining, in particular to a carrying and positioning mechanism for lock cylinder machining and a working method thereof. The carrying and positioning mechanism comprises a base table, a protection frame, a frame body, a moving assembly, a second hydraulic cylinder and a clamping and fixing assembly, a lock cylinder is clamped through the clamping and fixing assembly to be positioned, the lock cylinder is firmly clamped through a chuck, the lock cylinder can be moved away from a conveying chain through the moving assembly, so that the mechanism can position the lock cylinder more reliably, the use reliability of the mechanism is further improved, the clamping and fixing assembly is installed on the moving assembly, the clamping and fixing assembly can position the lock cylinder to a wider range, more powerful positioning support is provided for other mechanisms to machine the lock cylinder, the compatibility of the mechanism is improved, the situation that the lock cylinder deviates in the conveying process of the conveying chain is avoided through the arrangement of a guide rail, and then it is guaranteed that the mechanism operates more stably, reliably and accurately.

The invention discloses a compressed type shading curtain winding device of an internal sealing tube. The compressed type shading curtain winding device includes core iron, an inner tube, a spring bead and a torsion spring, wherein the inner tube is used for winding the shading curtain, and the spring bead and the torsion spring are accommodated in one end of the inner tube. A center hole coaxial with the core iron is preserved in the spring bead. The spring bead is formed by clamping a male spring bead and a female spring bead. One end of the core iron is connected with an internal sealing cover, and the other end of the core iron is connected with a fixing block of the core iron. A compressed spring is sleeved on the core iron and is accommodated in the center hole preserved in the spring bead. At least two clamping tenons are arranged on the core iron. Compression through the internal sealing cover replaces integral compression of the external sealing cover, and the external sealing cover only needs to be fixedly matched with the external tube, so friction noise and friction marks generated through sliding fit of the external sealing cover and the external tube are reduced.