78 results about "Sulfuryl fluoride" patented technology

A TPC-OTBS n-hexane solution is added to a mixture of TPC-OSO2F, DMF, and DBU and allowed to stand to produce a crosslinked solvent gel; the crosslinked solvent gel is added to methanol, stirred, and dried to produce the porous crosslinked material. The gel acquired can be prepared into a pore-rich solid porous organic polymer material by means of solvent exchange. SEM and TEM are used to characterize the surface and internal morphologies of the solid material, and the porous morphology thereof is discovered, with large pores being the majority. Infrared and nuclear magnetic resonance are used to characterize the structure of a crosslinked polysulfate; the complete reaction of a sulfuryl fluoride group is proven by means of solid-state fluorine nuclear magnetic resonance spectroscopy and XPS element analysis; and the porous structure of the crosslinked polysulfate allows same to be provided with improved application prospect in terms of adsorption.

The invention relates to a method and a device for preparing an organic alkali salt of bis (fluorosulfonyl) imide. Ammonia gas, sulfuryl fluoride and liquid organic alkali are adopted as reaction raw materials, and under the condition that no solvent is added or a small amount of solvent is added, the raw materials react through pressurization to generate the organic alkali salt of the bis (fluorosulfonyl) imide. As no solvent is used or only a small amount of solvent is used in the reaction, the chroma of the obtained product is relatively low, and subsequent preparation of lithium bis (fluorosulfonyl) imide as a precursor is facilitated. The invention provides a simple and effective method for reducing the chromaticity of the imidodisulfuryl fluoride salt.

A cyclic sulfate compound, and a preparation method therefor and the use thereof. The preparation method comprises the following steps: (1) dissolving mannitol and an organic alkali in an organic solvent, introducing a sulfuryl fluoride gas at -5 to 20°C, and continuing to react same for a certain time after the introduction is finished; and (2) adding phosphorus oxyfluoride to the solution, which has been subjected to the reaction in step (1), at -15 to 0°C, and continuing to react same for a certain time after the addition is finished, so as to obtain a cyclic sulfate compound represented by structural formula I. The preparation method provided in the present application can be used to simply and easily prepare the cyclic sulfate compound, as represented by structural formula I, having a high purity, low moisture and low acid value, with a high yield at a low cost, and the substance can satisfy the usage requirements of additives of a lithium-ion battery.

The application provides a preparation method of sodium bisfluorosulfonimide, which comprises the following steps: (1) sulfuryl fluoride and hexamethylsilazane are reacted in an inert atmosphere to obtain a crude product, and the crude product is subjected to gas phase separation to obtain bisfluorosulfonimide; (2) the bisfluorosulfonimide obtained in the step (1) is reacted with sodium fluoride to obtain the sodium bisfluorosulfonimide. The sulfuryl fluoride and the hexamethylsilazane are used as raw materials to prepare the bisfluorosulfonimide by one-step method, the cost is reduced, and the production safety is improved, then the sodium bisfluorosulfonimide is prepared by ion exchange reaction of the bisfluorosulfonimide and sodium fluoride, the three wastes and solvent use are reduced, the impurities are reduced, and the production safety and product quality are improved.

The invention relates to the technical field of chemical synthesis, and discloses a preparation method of anhydrous N, N-dimethyl amino sulfuryl fluoride, which comprises the following steps: (1) introducing sulfuryl fluoride gas into a dimethylamine organic solution to carry out nucleophilic substitution reaction, and then adding triethylamine to obtain a mixed solution containing N, N-dimethyl amino sulfuryl fluoride; and (2) sequentially carrying out normal-pressure rectification and reduced-pressure rectification on the mixed solution containing the N, N-dimethyl amino sulfonyl fluoride to obtain the N, N-dimethyl amino sulfonyl fluoride. According to the method, water is not introduced in the whole process, the risk of water residue is avoided, and the prepared product is high in yield and purity.

The utility model discloses a sulfuryl fluoride local fumigation device which comprises a sulfuryl fluoride gas bottle, a flow controller, a gas flow uniformizing part, an electric control cabinet and a local fumigation pesticide applying pipe. The flow controller is communicated with a bottle opening of the sulfuryl fluoride gas bottle through a hose; the gas flow uniformizing part is communicated with the flow controller through a hose; the electric control cabinet is detachably connected to the frame of the gas flow uniformizing part and electrically connected with the flow electric control cabinet and the gas flow uniformizing part. The plurality of local fumigation pesticide application pipes are communicated with the gas flow uniformizing part through hoses; the device has the advantages that the concentration of the introduced sulfuryl fluoride gas is diluted by adopting a mode of mixing the air with the sulfuryl fluoride gas, so that the lethal dose of stored grain pests is accurately reached, the medicament waste is avoided, and compared with the original mode of directly introducing the sulfuryl fluoride gas, the use amount of the sulfuryl fluoride gas is effectively reduced, the fumigation cost is saved, and the environment is protected. And the use amount of the sulfuryl fluoride gas is small, so that the residue of the sulfuryl fluoride gas is avoided, and the quality of grains is ensured.

The invention provides an imine lithium compound, a preparation method thereof and application of the imine lithium compound in a battery. The structural formula of the lithium imide compound is as shown in the formula I in the specification. The preparation method of the lithium imide compound comprises the following steps: adding sulfuryl fluoride, ammonia gas and an acid-binding agent, and carrying out ammonification reaction to obtain a first intermediate; adding phosphorus trichloride into the first intermediate, and carrying out phosphating reaction to obtain a second intermediate; adding ethylene glycol into the second intermediate for substitution reaction to obtain a third intermediate; and adding a lithiation compound into the third intermediate to carry out lithiation reaction. As a new substance, the lithium imide compound contains a fluorosulfonyl imide group and a cyclic phosphate group, has the advantages of cyclic phosphate, sulfonyl imide group and fluoro group, has a good application prospect, can be applied to a secondary battery, and can also be used as an intermediate for material and medicine processing. # imgabs0 #

The invention provides a method for preparing sulfuryl fluoride chloride by an electrolytic process, which comprises the following steps: introducing sulfuryl chloride and hydrogen fluoride into an electrolytic bath, adding a conductive additive, and introducing direct current for electrolysis to obtain the sulfuryl fluoride chloride in one step, according to the method, reaction can be performed at normal temperature and normal pressure, by-product impurities such as sulfamic acid are not generated, the product purity is relatively high, and continuous production can be realized.

The invention belongs to the technical field of chemical engineering and fine fluorine chemical synthesis, and particularly relates to a preparation method of sulfuryl fluoride chloride. According to the preparation method, through the synergistic effect of a gas-liquid reaction system and a closed-loop circulation system, a tertiary amine hydrofluoric acid adduct (such as Et3N.nHF, n = 2-6) is used as a fluorinating reagent, sulfuryl fluoride chloride is generated through a rapid cross-flow reaction in excessive sulfuryl chloride (SO2Cl2) under the conditions that the temperature is 65-100 DEG C and the pressure is 0.5-2.0 MPa, and a liquid-phase byproduct tertiary amine hydrochloride hydrogen fluoride adduct (such as Et3N.HCl. (n-1) HF) is used for preparing the sulfuryl fluoride chloride. Supplementing hydrogen fluoride to regenerate the catalyst and recycling; and after a gas-phase product is pressurized, rectified and purified by a light component removal tower and a heavy component removal tower, totally returning a light component (Cl2 / SO2) and a heavy component (SO2Cl2) to a synthesis system for recycling. According to the method, the reaction temperature, the reaction pressure, the liquid phase dispersion degree and the contact time are accurately controlled, so that the reaction product generates SO2FCl with high selectivity, and the byproduct (R3N.HCl. (n-1) HF) is kept in a liquid phase, so that the reaction can be continuously carried out, and conditions are created for subsequent treatment.

The invention relates to a method and a device for continuously producing sulfuryl fluoride. The method is a gas-solid reaction among reaction raw materials, does not need to use a solvent and a catalyst, is high in production efficiency, short in production period, high in sulfuryl fluoride yield and low in production cost, and can realize continuous production.

The invention discloses a preparation method of sulfuryl fluoride and the sulfuryl fluoride. The preparation method comprises the following steps: mixing fluoride salt powder and an anti-sticking agent to obtain a mixture; introducing sulfuryl chloride gas into the mixture for reaction to prepare sulfuryl fluoride; wherein the anti-sticking agent is used for preventing the fluoride salt powder from being stuck. According to the technical scheme, the production cost is reduced, the product purity is improved, and the method is suitable for industrial production.

The invention discloses a method for preparing mildew-proof and insect-resistant wood by adopting a sulfuryl fluoride modification strategy and application of the mildew-proof and insect-resistant wood, belongs to the field of wood chemical modification, and aims to solve the problems that mildew-proof and insect-resistant active ingredients are easy to migrate and lose, the environmental toxicity is high and the like in an existing wood protection method. According to the method, sulfuryl fluoride (SO2F2) is utilized to react with phenolic hydroxyl groups in wood in the presence of alkali to generate covalent linkage of aryl fluorosulfate (Ar-O-SO2F), so that wood modification is realized. The reaction is simple and feasible, and can be carried out under mild conditions. The shape of the wood modified through sulfuryl fluoride is kept, and the wood shows stable performance in the aspects of mildew prevention, insect resistance and the like. The modification method does not depend on transferable effective components, can provide a lasting protection effect for wood, and has a wide application prospect.

The invention belongs to the technical field of organic intermediate synthesis, and in particular to a kind of synthetic method and synthesis device of benzenesulfonyl fluoride.The synthetic method of benzenesulfonyl fluoride of the present invention, comprises the following steps: first hydrogen fluoride and sulfuryl chloride are added to a premixer, and successively pass through tubular reactor a, b, c, enter terminal reactor mixed reaction, control gas-liquid two-phase mixed reaction by terminal reactor, vertical condenser a, prepare sulfuryl fluoride chloride, then sulfuryl fluoride chloride, benzene, catalyst are mixed, enter sulfonation reactor reaction, control the progress of sulfonation reaction by sulfonation reactor, vertical filler b, obtain mixed reaction liquid, finally mixed reaction liquid is distilled, collect fraction, obtain benzenesulfonyl fluoride.The synthetic method of benzenesulfonyl fluoride provided by the present invention, reaction condition requirement is low, stable, easy to control, unit consumption is low, subsequent easy processing, prepared benzenesulfonyl fluoride yield is high, purity is high.The present invention also provides the synthesis device adopted by the synthetic method of benzenesulfonyl fluoride.

The utility model discloses a sulfuryl fluoride gas adsorption and purification device, which relates to the technical field of gas adsorption and purification and comprises a purification device main body, a sealing cover is abutted against the top of the purification device main body, a driving motor is detachably mounted in the center of the top of the sealing cover, and a stirring blade is detachably mounted at one end of the output end of the driving motor. According to the sulfuryl fluoride gas adsorption and purification device disclosed by the utility model, the driving motor is arranged to drive the stirring blades to stir and mix alkali liquor and sulfuryl fluoride gas in the liquid storage barrel, and the alkali liquor in the liquid storage barrel is mixed with the sulfuryl fluoride gas to quickly adsorb part of the sulfuryl fluoride gas, so that the adsorption efficiency is improved, and the sulfuryl fluoride gas in a closed space can be quickly removed; the purification time is saved, the working efficiency is improved, the alkali liquor in the liquid storage barrel is secondarily utilized through the arranged liquid storage tank, the alkali liquor is sequentially replaced, the alkali liquor is used in sections, alkali liquor adsorption is more saturated, waste is reduced, the alkali liquor in the liquid storage barrel is continuously replaced, the purification effect is not reduced, and the adsorption efficiency is kept.

The utility model relates to the technical field of container fumigation quarantine, and discloses a port import container fumigation quarantine device which comprises a quarantine device body, a connecting block is fixedly connected to the outer wall of the quarantine device body, and a fixing plate is fixedly connected to the side, away from the quarantine device body, of the outer wall of the connecting block. A clamping assembly is arranged in the fixing plate, a sulfuryl fluoride tank is slidably connected into the fixing plate, the clamping assembly comprises a telescopic rod, one end of the telescopic rod is fixedly connected to the inner wall of the fixing plate, the other end of the telescopic rod is fixedly connected with a first extrusion block, and the outer wall of the telescopic rod is slidably connected with a first spring. According to the fumigant storage tank fixing device, a worker pushes the fumigant storage tank by hand to extrude the first extrusion block to enable the first extrusion block to enter the groove of the fixing plate, and the first extrusion block loses stress and returns to the original position to block the mounting opening, so that the time required for replacing the fumigant storage tank is shortened, and the working efficiency is improved.

The invention provides a method for preparing sulfuryl fluoride without loss by using a catalyst. According to the method, a tertiary amine catalyst is used for catalyzing a liquid phase reaction with sulfuryl chloride (or sulfur dioxide and chlorine) and hydrogen fluoride as raw materials, and sulfuryl fluoride gas and hydrogen chloride gas are obtained. By controlling the amount of hydrogen fluoride added into the system, the tertiary amine is not separated out as a solid precipitate while being used as a catalyst, but still exists in a liquid phase reaction system for cyclic utilization, so that the reaction can be continuously carried out without continuously adding the catalyst. According to the method, the production cost of the sulfuryl fluoride is reduced, the purity and yield of the sulfuryl fluoride are improved, waste needing follow-up treatment is not generated, and the method is suitable for industrial production.

The present invention relates to a synthesis method for sulfate ester (amine) type linker polymer, which comprises a monomer containing hydroxyl or amino group and sulfuryl fluoride monomer proceeding a polycondensation reaction under a basic condition by one-pot process. As compared to the traditional polyester synthesis method, the present invention is economical; the reaction conditions are mild and easy to control, the reaction process is simple and easy to operate; the post-treatment process is simple with little environmental pollution, which is beneficial to industrial production. In addition, the bisphenol type polysulfate ester compounds synthesized by the present invention have excellent mechanical performances, dielectric performances, tolerance performances, and abrasion resistance performances.

The utility model relates to the technical field of metering equipment, in particular to sulfuryl fluoride metering equipment for granary fumigation, which comprises a metering cylinder, a piston, an air outlet pipe and a driving component, a plurality of metering cavities are arranged in the metering cylinder in an array manner, a distribution cavity is arranged at the bottom of the metering cylinder, the distribution cavity is unidirectionally communicated with the metering cavities, and the piston is arranged in the piston. The distribution cavity is communicated with a sulfuryl fluoride source, the piston is connected into the metering cavity in a sliding mode, the air outlet pipes correspond to the metering cavity in a one-to-one mode and are communicated with the metering cavity, the free ends of the air outlet pipes extend out of the metering cylinder, and the driving assembly is used for driving the piston to slide up and down in the metering cavity. According to the sulfuryl fluoride metering equipment for grain fumigation, disclosed by the utility model, one or more granaries can be fumigated at the same time.

A pretreatment process for an anode for an electrochemical battery cell, comprising the following steps: a) supplying an anode, b) placing the anode in the presence of sulfuryl fluoride (SO2F2) gas until a layer comprising the -F and -SO2F groups forms on the surface of the anode, c) removing the SO2F2 gas to stop the reaction between the SO2F2 and the anode material, and d) recovering the pretreated anode obtained.

The utility model belongs to the technical field of synthesizing devices, and particularly relates to a synthesizing device of sulfuryl fluoride. The sulfuryl fluoride synthesizer comprises a reaction kettle (1), a condenser (2) and a venturi reactor (3), the reaction kettle (1) is connected with the condenser (2), two pipelines are arranged at the top of the reaction kettle (1), one pipeline is connected with the bottom of the venturi reactor (3), the other pipeline is connected with the side face of the venturi reactor (3), and the venturi reactor (3) is connected with the condenser (2). And a pipeline at the bottom of the reaction kettle (1) is connected with the top of the Venturi reactor (3). The utility model provides a sulfuryl fluoride synthesizer, which is suitable for liquid phase reaction, further improves the conversion rate of reaction, improves the purity and yield of products, and is small in toxic and side effects, low in risk and environment-friendly.

The invention discloses a method for recovering triethylamine in a preparation process of bis (fluorosulfonyl) imide triethylamine salt, which comprises the following steps: (a) taking sulfuryl fluoride, ammonia gas and triethylamine as raw materials, and reacting in an organic solvent to obtain a reaction solution containing bis (fluorosulfonyl) imide triethylamine salt and triethylamine hydrofluoride; (b) adding a phase transfer catalyst and an inorganic alkaline substance, and carrying out heat preservation reaction; (c) filtering to obtain solid fluoride salt and filtrate; and (d) carrying out vacuum evaporation concentration on the filtrate to obtain a concentrate and a triethylamine-containing recovered solvent, and using the triethylamine-containing recovered solvent for the next batch of reaction. According to the method, under the action of the phase transfer catalyst, the added inorganic alkaline substance reacts with the triethylamine hydrofluoride to generate the solid fluoride salt and dissociate the triethylamine, and the triethylamine can be recovered through vacuum evaporation and concentration, so that the method is simple to operate and convenient for industrial implementation, the triethylamine recovery cost is greatly reduced, and the method is suitable for industrial production. Meanwhile, the wastewater treatment difficulty is also reduced.

The invention belongs to the technical field of sulfuryl fluoride preparation methods, and particularly relates to a method for continuously preparing sulfuryl fluoride by a fluidized bed, which comprises the following steps: S1, by taking carbon tetrafluoride as working gas, pretreating a hydrogen fluoride-amine complex by adopting plasma for later use; s2, preheating a fluidized bed to 150-180 DEG C, adding fluoride salt powder and the pretreated hydrogen fluoride-amine complex into the fluidized bed, and heating to 190-200 DEG C; preheating the gasified sulfuryl chloride to 100-120 DEG C, and introducing the preheated sulfuryl chloride into the fluidized bed for two-stage heating reaction; and S3, carrying out gas-solid separation, and washing and drying the gas to obtain sulfuryl fluoride. The plasma treatment is combined with the fluidized bed, so that the synthesis efficiency is improved, the generation of byproducts is reduced, and the product purity is improved.

The utility model discloses a detector for the concentration of sulfuryl fluoride in a granary, and belongs to the technical field of concentration detectors. Comprising a remote control trolley, a rotating assembly is arranged at the top end of the remote control trolley, a rotating block is rotationally arranged in the rotating assembly, a detector body is arranged at the top end of the rotating block in a clamped mode through a clamping assembly, a first warning lamp and a second warning lamp are arranged on the remote control trolley side by side, and a power storage plate is carried in the remote control trolley. According to the device, the detector body is placed on the placement plate, the two clamping plates clamp the two sides of the detector body by pulling the two clamping plates and synchronously compressing the spring pieces, rapid fixing is achieved, the clamping pad has the anti-skid effect, the detector body can be rapidly carried on the remote control trolley, and the detection efficiency is improved. The remote control trolley is controlled to move to enter the granary, personnel can control outside the granary, and the situation that poisonous sulfuryl fluoride gas is inhaled in the granary is avoided.

The invention discloses a method for preparing bis (fluorosulfonyl) imide lithium salt by a one-pot method. The preparation method comprises the following steps: mixing sulfuryl fluoride, ammonium fluoride, lithium hydroxide (lithium carbonate) and specific amine according to a certain proportion, synthesizing bis (fluorosulfonyl) imide lithium salt in an organic solvent, and then carrying out solid-liquid separation and purification to obtain the high-purity bis (fluorosulfonyl) imide lithium salt. The preparation method comprises the following steps: sequentially adding ammonium fluoride, organic amine and lithium hydroxide (lithium carbonate) under the condition of shielding gas, and stirring and reacting at a proper temperature; the method is simple to operate and is carried out in one reactor. The reaction conditions are mild, and the use of dangerous chemicals in the traditional method is avoided. The core of the invention is innovation of the synthesis method. The method is simpler to operate, and the reaction process is safer and more green.

The invention provides high-crystallinity heat-conducting polysulfate and a preparation method and application thereof, and belongs to the technical field of semiconductor materials.The preparation method comprises the steps that 4-cyanophenol and hydrazine hydrate are subjected to a heating reaction, and after the reaction is finished, washing and vacuum drying are conducted to prepare a first intermediate; adding the first intermediate into an ethanol solution, carrying out a heating reaction in an oxygen atmosphere, and after the reaction is finished, carrying out washing and vacuum drying to prepare a second intermediate; reacting the second intermediate with a silanizing agent, and purifying after the reaction is finished to obtain a monomer containing a silyl ether group; reacting the second intermediate with sulfuryl fluoride gas, and purifying after the reaction to obtain a monomer containing a sulfuryl fluoride group; and carrying out polymerization reaction on the monomer containing the silyl ether group or the second intermediate and the monomer containing the sulfuryl fluoride group to obtain the high-crystallinity polysulfate containing the tetrazine structure. The prepared high-crystallinity heat-conducting polysulfate is stable in physical and chemical properties, high in crystallinity and high in heat conductivity, and the preparation method is simple, efficient and low in cost.

The application discloses a method for preparing sulfuryl fluoride by using sulfuryl chloride as raw material. After sulfuryl chloride is gasified, the sulfuryl chloride is reacted with an amine complex of hydrogen fluoride in a pipeline reactor to obtain sulfuryl fluoride. The pipeline reactor is in a two-stage series connection, the heating temperature of the first stage is 100-350 DEG C, and the heating temperature of the second stage is 150-450 DEG C. The method can effectively improve the conversion rate and yield of the product and is easy to be industrialized.

The utility model discloses a sulfuryl fluoride fumigation gas flow divider which comprises a distribution box, an air outlet valve and an air inlet valve are arranged on the side wall of the distribution box, the air inlet valve is connected with a first PE high-pressure pipe, and the first PE high-pressure pipe is connected with the tank body; a flowmeter is arranged on the other side wall of the distribution box and connected with an air pipe through a stainless steel connector, the air pipe is connected with the distribution box, the flowmeter is connected with an air outlet valve through a second PE high-pressure pipe, and the air outlet valve is connected with an output pipe. A 28 * 15 * 22cm stainless steel box body is designed and manufactured, five flowmeters (which can be increased or decreased according to actual requirements) are mounted on the box body, the flowmeters and gas pipes are connected through stainless steel joints, five gas outlet valves and one gas inlet valve are mounted on the corresponding surfaces of the box body, sulfuryl fluoride gas is led out by adopting a PE high-pressure pipe and is connected to the gas inlet valve of a gas distribution box, and the gas distribution box is connected with the gas inlet valve of the gas distribution box. The air outlet is connected with a PE (Poly Ethylene) high-pressure pipe, so that the air is drained to a preset medicine applying point, and the flow of the flow meter can be adjusted as required, so that the aim of precise medicine applying and fumigating is fulfilled.

The present invention relates to the technical field of ion battery materials, and discloses a method for preparing lithium bis(fluorosulfonyl)imide; the method comprises the following steps: introducing sulfuryl fluoride into a hydrofluoric acid aqueous solution of urea, reacting under the action of a catalyst to obtain an aqueous solution of bis(fluorosulfonyl)imide; adding lithium carbonate to the aqueous solution of bis(fluorosulfonyl)imide obtained in step S1, filtering and concentrating after the reaction to obtain a crude product of lithium bis(fluorosulfonyl)imide. The reaction of the present invention is a contact reaction of gas and liquid, with high production efficiency, mild reaction conditions, and easy control; and the present invention is a one-pot continuous reaction to obtain the target product, lithium bis(fluorosulfonyl)imide, separating bis(fluorosulfonyl)imide and combining it with lithium, and the steps are simple.

The application provides a synthesis method of difluorosulfimide. The method comprises the following steps: under nitrogen protection, fluorosulfonic acid, aminosulfonic acid and a catalyst are added into a reaction container, stirring is performed, and the temperature is raised to a reaction temperature; then sulfuryl fluoride is introduced, and the reaction is kept under temperature while the sulfuryl fluoride is introduced; after the reaction is completed, the difluorosulfimide is obtained through rectification. The method is simple in process, can quickly and efficiently synthesize difluorosulfimide, and the obtained difluorosulfimide has high yield and high purity.

The utility model discloses a sulfuryl fluoride dosing meter for grain fumigation, and belongs to the technical field of sulfuryl fluoride metering. Comprising a sulfuryl fluoride metering body, a temperature and pressure compensation part is arranged in the sulfuryl fluoride metering body, flanges are symmetrically arranged on the two sides of the sulfuryl fluoride metering body, and the two sides of the two flanges are connected with an air outlet pipe and an air inlet pipe correspondingly. The spacing between the air outlet pipe and the air inlet pipe can be lengthened, so that the sulfuryl fluoride metering main body can be conveniently mounted, one end of the sulfuryl fluoride metering main body is clamped with the air inlet pipe end, a limiting rod is loosened for limiting, a spring piece is restored, a sliding rod slides towards the interior of a hollow piece, and the air outlet pipe end actively approaches the sulfuryl fluoride metering main body end for clamping; through inward extrusion positioning installation of the spring piece, rapid assembly of the sulfuryl fluoride metering body is achieved, many nut limitations are reduced, and disassembly is labor-saving.