China Scratch Mat

Natural oxidation and corrosion of the valve stem, because the surface of the valve stem packing is oxidized, and ferroferric oxide (rust) is formed, which will cause the valve stem to become thin and cause leakage; For example, the use temperature of pure PTFE must be 150℃, filled with PTFE250℃, and PTFE particle filler The compensation performance is poor, and it is only suitable for low-pressure valves, PTFE fiber, carbon fiber or the mixed filler of the two, and the price is too high to be unfavorable for promotion.

A valve that relies on exteal force to rotate and drive to open and close is designed with a sealing device that is used to install a certain number of packing seals in the packing culvert to achieve a sealing effect, but how about the sealing? Leakage at the PTFE fiberglass fabric high temperature cloth packing of the valve is one of the most prone to leakage failure in the valve, but there are roughly two reasons for it.

Synthetic resins and synthetic fibers, some of these products are restricted in the scope of use. Corrosion problems can also be caused by one aspect., serious threats to personal safety, property safety and environmental pollution accidents. Asbestos, because the asbestos material has chloride ions that corrode the valve stem, and the asbestos contains carcinogens, which are harmful to human health.

The country has banned or seldom used the parts of the product; 2. Expanded graphite will cause severe electrochemical corrosion. If the water valve leaks, it will lead to serious consequences, such as poisonous, harmful, flammable, explosive and Corrosive media leakage, etc. Reasons for fillers The main fillers currently used are:  Corrosion situations include: 1.Valve leakage is very common in life and production, and it will cause waste or danger to life at the slightest. Leakage caused by chloride ion corrosion of asbestos packing;

The pipeline is relatively fixed. Except for the coal slurry pipeline which is still in the brewing stage, other pipelines for conveying media have been successfully constructed and operated in China. 5. The characteristics of long-distance pipelines Long-distance pipelines are one of the five major transportation industries of railways, highways, shipping, civil aviation and long-distance pipelines. In-service pipelines pose a long-term threat to ground structures or areas, especially natural gas, coal gas, LPG and other flammable gas pipelines, which pose a greater threat. Continuity of transportation.

The construction unit has no ability PTFE BBQ Mesh Mats to choose an ideal construction site..1. Except for special terrain, long-distance pipelines are generally laid underground, and it is not easy to find potential hazards during operation, especially defects that have not been detected during construction. In addition to the common petroleum and natural gas, the transportation medium also includes industrial gases such as oxygen, CO2, etc. The construction operation points are constantly moving along with the construction progress. 2. That is, the pipeline is buried in the ground. Except for reasons such as reconstruction and laying of new lines, the pipeline will generally not be displaced. The topography has a direct impact on welding, so it must be adapted to local conditions.

Therefore, pipeline welding quality is an extremely important factor affecting pipeline quality. Compared with the production of factory products, the difficulty of construction management, quality management, safety management, etc. is increased; because the welding operation is in a flow state, it is relatively difficult to ensure quality. A long-distance pipeline may encounter a variety of terrains? For example, the West-East Gas Pipeline Project will pass through Gobi, deserts, loess plateaus, mountains, plains, water networks, etc. Characteristics of welding in the construction of long-distance pipelines 1．

The influence of fluidity construction on welding quality. As a separate system in the transportation industry, the pipeline differs from other transportation systems in the following aspects: 1. That is, once the pipeline is completed and put into production, it should be operated continuously under normal circumstances, which correspondingly increases the difficulty and danger of continuous transportation and maintenance under pressure., ethylene, liquid ammonia, mineral slurry, coal slurry and other media.

Choose different welding methods to meet the needs of the project. 2. from west to east. The pipeline and the conveying medium flow relatively, which requires the inside of the pipeline to be as smooth as possible to reduce abrasion resistance; in addition, considering the corrosiveness of the medium, a corresponding margin should be increased in the design. The influence of topography on welding quality. 2. The above analysis shows that the quality of the pipeline is very important for its safe operation and service life. 3

At present, most foreign oil seal lip pieces adopt moulded threaded type, while domestically, the tued threaded type is basically adopted.. However, due to its complex structure, large pressing force and low life span, it is rarely used. By tuing the thread on the end surface, the follow-up type of the shaft is improved, so that the sealing performance, especially the static sealing, can be greatly improved. 

This kind of oil seal was developed in the 1980s and is called the first Five-generation products. The second generation is Japan's Arai company invented a paste type seal, which is to paste a layer of PTFE film on the side of the original rubber sealing lip to improve the rubber sealing performance. However, due to the complex bonding process and high cost, the performance is improved. Not many and cannot be widely adopted. Until 1975, the American Mather company first proposed a wide lip structure of PTFE seal, called the fourth generation product, that is, the PTFE material is first pressed into a circular sheet, then pulled into a ho shape, and then clamped in the metal.  

 In the shell, there is a layer of rubber elastic sheet in the middle. Because PTFE has high self-lubricating properties, the lips are not easy to bu out. It uses the function of the thread groove to make a layer of oil film on the shaft surface receive the thrust of the thread groove, thereby preventing the oil film from leaking outward.PTFE was first used in the military industry and was not used for static sealing elements until the 1950s. 

The seal of this new structure is obviously different from the previous Gas Top Protectorsrubber seals, not only the structure is simple, no coil spring is needed, and the contact area with the shaft is wide, generally 3~4mm. However, the inner wall of the lip of this type of seal is smooth and the oil sealing effect is not good. Therefore, a dynamic seal with a 'reverse-rotating thread groove' engraved on the inner wall of the lip appeared. 

The first generation of PTFE seals was made of PTFE rods by tuing or pressing into products similar to rubber seals, but it quickly failed. Beginning in the 1970s, some large foreign companies imagined using PTFE to replace rubber to make lip seals. Later, the company introduced the third-generation seal, which uses PTFE material to draw a ho-shaped membrane, covered with a spring leaf, wrapped a coil spring, and used it to load the lip. The emergence of the fifth generation of products has made a qualitative leap in the lip-shaped rotary seal

The opener, mixing box, carding machine and netting machine must be grounded as a whole to eliminate or reduce the static electricity generated during fiber transfer, carding and netting.As we all know, PTFE fiber has high static electricity, low crimp, smooth fiber, poor cohesion, and high density. The control of uniformity is a very important indicator in the production of needle punched filter felt.

Control of uniformity and surface density of needle-punched felt In the application of needle-punched filter felt, the uniformity directly affects its service life. Overcoming these difficulties involves the key technology for the production of 100% PTFE needle punched filter materials. It is very difficult to comb and lay such fiber. (2) Adjust the position of the inclined curtain of the carding machine and the conveying curtain of the web-laying machine, so that the wool net can be completely transferred, and reduce the problem of net breakage caused by the weight and small cohesive force of the PTFE fiber wool n

Adjust the speed of each transfer point to solve the problem of the fleece being pulled off due to the small cohesive force between the fibers and the excessively fast transfer speed. In order to ensure the smooth carding and transfer of PTFE fibers, and reduce the abnormal net leakage and net breakage, some parts of the equipment must be modified and adjusted to solve the problems of carding, netting, and netting.

Transform the distance between the reciprocating drive of the net-laying machine and the bottom curtain to be adjustable, so that the drop between the transfer points of the net-laying machine is adjustable, and control the different surface density of the wool net to be continuously and normally transferred, and solve the problem of The problem of network disconnection caused by self-heavy weight and small cohesive force between fibers during the laying process.

The modification and adjustment of the equipment are as follows:  Adjust the distance between the cylinder and the work roll, transfer roll, and doffer in the carding machine so that the fibers can be combed smoothly and reduce the effect of small PTFE fiber curl on the carding; The distance between the knife and the doffer allows the output fleece to be completely peeled from the doffer, ensuring that the carding machine can output the fleece continuously and evenly.

In order to ensure the uniformity of 100% PTFE needle punched filter felt, the following measures should be taken:. 1 Carding, web formation and web-laying According to the characteristics of PTFE fiber, it needs to be treated with antistatic, select a suitable antistatic agent, spray it evenly on the fiber, and then leave it to balance for a certain period of PTFE adhesive tape time

　　 Teflon PTFE: PTFE (polytetrafluoroethylene) non-stick coating can be used continuously at a high temperature of 260 ℃, the highest use temperature can reach 290-300 ℃, very low friction coefficient, good wear resistance and excellent chemistry stability.

Teflon spraying (paint), the English name is TEFLON, is a kind of fluorine coating with PTFE coated fiberglass tape polytetrafluoroethylene as the matrix resin, because of the pronunciation, it is usually called Teflon, Teflon, Teflon Dragon, Teflon, Teflon, etc. Its flexible applicability makes it widely used in: cookware, tableware, fuiture, molds, home appliances, automobiles, machinery, medicine, technology and so on.

Teflon (Teflon) coating is a special high-performance coating (paint) that combines heat resistance, chemical inertness, excellent insulation stability and low friction. It has comprehensive advantages that other coatings cannot compete.  Teflon is divided into four types: PTFE, FEP, PFA, and ETFE. (all are the transliterations of TEFLON)

Filled products containing glass fibers are suitable for sintering in nitrogen. . has developed rapidly in chemical anti-corrosion.. The sintering process of the filled product is the same as that of pure PTFE. Commonly used fillers according to these requirements are: glass fiber, carbon fiber, graphite, quartz sand, molybdenum disulfide, amorphous carbon, calcium fluoride, bronze powder, ceramics, polyimide, polyphenylene, polyparahydroxyformate, etc. Improve the pressure resistance, wear resistance, cold flow resistance, heat resistance, dimensional stability, etc.

Solvent mixing, the solvent is acetone or methanol, suitable for glass fiber filled PTFE. New application areas of PTFE. But for filled products containing MoS2, it is required to sinter in air at 360°C or in nitrogen at 380°C. Main applications It is used as oil-free lubrication bearings, bearing pads, piston rings, machine tool guides, etc. in the machinery industry. PTFE filled in foreign countries is generally completed by PTFE resin production plants, such as HosTaflonTF4000 series and HosTaflonTF3000 series of Hoechst in Germany And the HosTaflon2000 series.

In our country, because PTFE BBQ Mesh Mats PTFE resin production technology lags behind processing technology, PTFE filling technology is completed in product processing plants. of PTFE by adding different fillers such as inorganic, metal, and polymer to the PTFE resin. Compared with pure PTFE, the filled products have 5-10 times higher pressure resistance, 1000 times higher wear resistance, 80% lower linear expansion coefficient, 5 times higher thermal conductivity, and reduced volume resistance and surface resistance.

In recent years, the application of filled PTFE as the lining of pipes, valves, pumps, etc.Among polytetrafluoroethylene (PTFE) products, filled polytetrafluoroethylene (PTFE) products are the one with the largest output. There are currently three mixing methods used to fill PTFE: (1) The dry mixing process requires the mixing device to be fast, uniform and free of dead ends, and is suitable for products with general requirements.

The molding pressure of the filled PTFE product depends on the volume ratio of the filler in the PTFE, such as: 250 bar with 5% filler; 350 bar with 6%-10% filler; 500 bar with 12%-25% filler ; With more than 25% filler molding pressure 700 bar. Filled PTFE products generally adopt a compression molding process: the quality of filled PTFE products mainly depends on the choice of resin filler, the design of the formula, the uniformity of material mixing and other factors. (3) Wet mixing: The products formed by this process have high mechanical strength, low wear and good corrosion resistance

The reactivity of these compounds is very high. The principle is: Na transfers the outermost electrons to the empty orbital of naphthalene to form anionic radicals; then forms an ion pair with Na+, releasing a large amount of resonance energy, and forming a mixed solution of dark green metal organic compounds.064nm) is greater than that of hydrogen atoms (0.

The helical conformation just surrounds the PTFE's carbon chain skeleton, which is vulnerable to chemical attack, forming a tight and complete;fluorinated; protective layer, so that the PTFE main chain is not attacked by any exteal reagents, so that PTFE has other materials Unmatched solvent resistance, chemical stability, and low cohesive energy density; at the same time, the carbon-fluorine bond is extremely strong, with a bond energy of 460.05~1u0026mu;m, the surface tension of PTFE is 18. Because the radius of fluorine atoms (0. When in contact with PTFE, sodium can break the CF bond, tear off part of the fluorine atoms on the surface of PTFE, and leave a carbonized layer on the surface ,

Polar groups such as COOH; the depth of the carbonized layer is about 0. Structural analysis of PTFE properties: In PTFE, fluorine atoms replace hydrogen atoms in polyethylene. The unbranched symmetrical main chain structure of PTFE also makes it highly crystalline, so processing is more difficult.1.2 High temperature melting method The advantage of this method is that it has better weather resistance and heat resistance than other methods, and is suitable for long-term outdoor use; the disadvantage is that PTFE will release a toxic substance during high temperature sintering, and the shape of the PTFE membrane is not easy to maintain.

Reducing agent method (sodium-naphthalene solution replacement method) The sodium-naphthalene solution replacement method is the sodium-naphthalene solution replacement method that has better effect and wider application among the various modification methods currently known.2kJ/mol, which is much higher than the carbon-hydrogen bond (410 kJ/mol) and carbon- Gas Stove Top Protectors The carbon bond (372 kJ/mol) is high, which makes PTFE have better thermal stability and chemical inertness.

In addition to sodium-naphthalenetetrahydrofuran corrosive solution, treatment solutions such as sodium-biphenyldioxane and sodium-naphthalene glycol dimethyl ether also have good effects.5u0026times;10-3N/m, and the surface has high surface energy.028nm), the carbon-carbon chain is stretched from the plane of the polyethylene and twists and tus. 2.. Surface modification method of PTFE: 2.

Ductility; at the same time, PTFE has poor creep resistance and is prone to cold flow. In addition, the electronegativity of the fluorine atoms is extremely large, and the tetrafluoroethylene monomer has perfect symmetry, which makes the attraction and surface energy between PTFE molecules low, so that PTFE has a very low surface friction coefficient and good at low temperature. The conformation gradually twists to the helical conformation of PTFE

PTFE anti-corrosion products can replace a large number of alloy material products, increase the working capacity of equipment, and reduce downtime and maintenance. In the wave of adopting new technologies and new materials to develop new anti-corrosion products, PTFE anti-corrosion products stand out and develop rapidly. Plastics were first used in our country as polytetrafluoroethylene, followed by fluoroplastics such as polytetrafluoroethylene, polytrifluoroethylene, and polyperfluoroethylene, as well as thermoplastics such as polyethylene, polypropylene, and ABS. It can withstand almost all commonly used strong corrosive and oxidizing chemicals.

Through the research of processing and molding technology, the application of PTFE anti-corrosion products in industry has become more and more extensive. With the advancement of science and technology, the development of traditional anti-corrosion equipment made of non-metallic materials has become more and more perfect, and new types of anti-corrosion non-metal materials are constantly emerging. It also has the characteristics of high temperature resistance, so it is an ideal anti-corrosion material. Polytetrafluoroethylene (PTFE for short) has a high degree of chemical stability.

The raw materials involved include various gases, liquids, and solids. The physical properties are vastly different and require various types of production equipment. After that, people began to explore the use of non-metal resources to replace metals. In the case of underdeveloped technology, people always look for anti-corrosion agents in metals. However, these devices are often expensive and cannot solve a large number of corrosion

problems.Chemicalproduction plants are carried out under certain temperature and pressure conditions, and the process requirements are strict. It is a corrosion-resistant product with ptfe coated fiberglass adhesive tape Manufacturers great development potential. However, the equipment in contact with the medium is corroded at all times during production, which severely restricts the development of chemical and other industries