Symptoms Sealed pronunciation or gassing (intermittent shaking). The static ring is bitten and eroded, resulting in a comet-like texture process that causes the outer edge of the narrow ring to be trimmed. Corrective measures Use wear-resistant materials as the end surface; improve the circulation conditions: hydrocyclone, external clean flushing; end surface deformation Symptoms When the pump is started, the seal leaks and the amount of leakage changes over time.

Corrective measures Natural aging deformation, re-grind; improper assembly, re-assemble carefully; poor alignment of the pump and bearing damage, adjust the pump. Coking High-temperature hydrocarbons often experience coking failures. The hard ring is thermally cracked.Common causes of seal failures in general mechanical seal analysis are usually obtained through analysis of the process experienced in use. Gently grind the end face on the platform, showing signs of deformation. The sealing life is short.

Dry operation There is insufficient or no liquid between the end faces. Vaporization (flashing) When the friction heat of the sealing surface accumulates, the liquid film between the end surfaces will locally boil. When the pump is stopped, the liquid viscosity increases due to the drop in temperature, which causes problems in restarting the pump. a. The rubber ring is hardened. Graphite ring powder accumulates on the outside of the Gland. Symptoms: Carbon graphite particles come off the end surface; the hard ring has polishing marks; graphite particles remain in the small gaps.

There is graphite dust accumulation at the inner edge of the end face. Corrective measures Check seal design parameters; improve circulation conditions. Symptoms Solid particles remain or accumulate on end faces and small gaps. Seal leakage and gel freezing. The graphite ring has record grooves. c. Corrective measures Choose balanced seals; choose hard materials with high thermal conductivity; check exhaust conditions; improve circulation conditions. Stable dripping on the sealing surface.

Abrasive wear The medium contains abrasive solid particles. Symptoms The stationary ring has severe wear and grooves. f. Pump and (or) shaft vibration.There are traces of polishing on the surface of the hard ring, or radial cracks (hot cracks) and discoloration. Seal screams while working.

Gas shock (spatter and splash) during sealing work. g. When the leakage of the liquid film is small, the air side of the seal will have a tendency to coke, which will prevent the end face from following and cause end face wear. Blister The shear stress between the ends of the high-viscosity liquid exceeds the breaking strength of graphite. Corrective measures Check the circulation; use 15~30min PTFE coated fiberglass fabric steam preheating or ※low pressure steam insulation

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The chlorotrifluoroethylene-vinyl ether copolymer is a strictly alternating copolymer ; and the stability of the molecular chain is poor because of the monomer competition rate. The molecular structure of the chlorotrifluoroethylene-vinyl ester copolymer is a non-strict alternating copolymer , and there are continuous vinyl ester copolymerized fragments.

The chain link also reduces its fluorine content to about 25%. Due to the further increase in fluorine content (>35%), tetrafluoroethylene-vinyl ether coatings have better weather resistance, chemical resistance, corrosion resistance and antifouling properties than trifluorotype coatings. Tetrafluoroethylene-vinyl ether has no chlorine atoms in the fluoroolefin chain link, so its effect in the field of corrosion prevention is improved.

Although the fluorine content is only about 1% lower than the chlorotrifluoroethylene-vinyl ether copolymer, its aging resistance is much worse, and it can only resist artificial aging to 2000-3000 hours, which is more than 1000 hours. At present, almost all domestic fluororesins on the market are such fluororesins, and the fluorine content is only 23. This is where the chemical resistance and weather resistance are poor.

Next, I will explain the difference between tetrafluororesin and trifluororesin in normal temperature curing fluorocarbon coatings for steel structure coating.Room temperature curing FC-S202 fluorocarbon coating adopts Zeffle GK-570 tetrafluoroethylene-hydrocarbyl vinyl ether fluorocarbon resin of Daikin Chemical of Japan as the film-forming material, which can ensure the 20-year outdoor service life of the coating.5%.

Nowadays, the most commonly used fluoroolefin-ethylene multi-element copolymer FEVE resin in room temperature curing fluorocarbon coatings has four categories, chlorotrifluoroethylene-vinyl ester multi-element copolymer, trifluorochloroethylene-vinyl ether multi-element copolymer, tetrafluoroethylene Ethylene-vinyl ester multi-element copolymer, tetrafluoroethylene-vinyl ether multi-element copolymer. The second is to ensure the quality of construction.

The vinyl ether fragments are Wholesale PTFE Fusing Belts Manufacturers shielded and surrounded by the more stable chlorotrifluoroethylene fragments, so the aging resistance is good, the fluorine content is about 26%, and the artificial aging resistance exceeds 4000 hours

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The transition temperature of 19°C is very important for processing PTFE blanks. This characteristic determines that PTFE cannot be processed by high temperature melt extrusion commonly used in general thermoplastic resins, but similar The pressure and sintering method of powder metallurgy is combined.

During the process of molding the blanks with PTFE powder resin, if the temperature of the pressed blanks is lower than 19°C, when the finished blanks are at 19°C At a temperature above ℃, the lattice distance will change, which is the deformation of the blank product, which will eventually cause the internal cracking of the blank product. 327℃ is the melting point of polytetrafluoroethylene. Therefore, the temperature for processing the PTFE blank is generally selected between 19 and 29 ℃. Therefore, it has been widely used in the wire and cable industry. The following is a brief introduction to the performance of PTFE..

Strictly speaking, above this temperature, the crystalline structure disappears, and the polytetrafluoroethylene transforms into a transparent amorphous gel state, and the volume ratio increases by PTFE coated fiberglass tape Manufacturers 25%. Its crystal lattice distance changes at 19℃, 29℃, 327℃, and there are turning points, that is, the volume of the crystal will change at this temperature.Polytetrafluoroethylene is abbreviated as F-4 (TFE or PTFE), which is polymerized by tetrafluoroethylene. It is an unbranched linear polymer with a completely symmetrical molecular structure.

Therefore, during the sintering process, the heating rate near the melting point must be slow to make the product inside and outside The temperature is uniform, otherwise there will be stress inside the product, or even cracking in severe cases. The melt viscosity in the glue state is still as high as 1010~1011Pa\u0026middot;S at 360℃, and still cannot flow. This structural feature makes PTFE have a higher frequency range and high and low temperature range, excellent chemical stability, high electrical insulation and weathering resistance.

This is that the CC main chain is not attacked by ordinary active molecules, and the fluorine atoms on the main chain of the macromolecule are symmetrical with each other, so the electrical properties Neutralization, the whole molecule has no polarity. Physical properties Polytetrafluoroethylene is a polymer with high crystallinity. Among the known polymer bonds, the CF bond is One of the strongest bonds, most of the main carbon chain is tightly surrounded by fluorine atoms. Due to the low thermal conductivity of PTFE, the volume changes greatly at the temperature above and below the melting point. 

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 Main equipment and instruments High-shear dispersing emulsifier, FM200, Shanghai Fluke Electromechanical Equipment Co.Keywords: polytetrafluoroethylene (PTFE); solid glass beads (SGM); silane coupling agent; mechanical properties; crystallinity Chinese Library Classification Number: TQ325., Ltd.4 Document Identification Code: A Article Number: 1001-5922 (2013) 10-0063-05 High-performance sealing material is an indispensable functional material in the aerospace field PTFE coated fiberglass tape .

SGM is a solid glass sphere with a tiny diameter, which is made by pulverizing glass and firing at high temperature. The results show that KH550 improves the compatibility of SGM particles with PTFE resin; with the increase of SGM content, the tensile properties and crystallinity of the sealing material decrease, and the Shore D hardness and compression recovery performance increase.

PTFE has excellent chemical resistance, high and low temperature resistance, aging resistance, and low friction.; Silane coupling agent, KH550, Nanjing Pinning Coupling Agent Co. Company; Acetone, analytical grade, Tianjin Tianda chemical reagent..; Environmental Scanning Electron Microscope (SEM), Quanta 200, FEI Hong Kong Co.1 Main raw materials Polytetrafluoroethylene resin, JF-4TM, Zhejiang Jusheng Fluorochemical Co. The influence of crystallization properties. In this paper, the surface activation treatment of SGM with silane coupling agent (KH550) is used to obtain modified solid glass beads. It is widely used in many civilian fields such as petroleum, chemical, electrical and medical [4-6]; but its smaller frequency Elasticity and poor creep resistance hinder its application in high-precision sealing areas., Ltd.

Abstract: The surface activation treatment of solid glass beads (SGM) with silane coupling agent KH550, and the preparation of SGM/PTFE sealing materials, analyzed the surface morphology of SGM before and after activation treatment, and examined the influence of SGM content on the mechanics of the sealing material Performance impact.; Plate vulcanizing press, QLB-D400\u0026times;40\u0026times;2, Xi'an Machine Tool Accessories Factory; High-temperature test chamber, WG-4501, Chongqing Yinhe Experimental Instrument Co., Ltd.

The SGM/PTFE sealing material is prepared by cold pressing sintering process, and the effect of SGM content on the mechanical properties of SGM/PTFE sealing material is studied. The rapid development of the defense industry has greatly promoted the development of high-performance sealing materials [1～3].; Solid glass beads, S-300, Qinhuangdao Qinhuang Glass Bead Co.; Differential Scanning Calorimeter, Q1000, American TA Company; Electronic Universal Testing Machine, CMT3502, Shenzhen New Sansi Metrology Technology Co., Ltd. Due to the characteristics of high roundness, good hardness, and strong wear resistance, it has been widely used in the fields of plastic rubber, wear-resistant floors, shot blasting and rust removal [7-9]. 

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Sliding: Teflon spray has a low coefficient of friction. The friction coefficient changes when the load is sliding, but the value is only between 0. Wear resistance: It has excellent wear resistance under high load. Heat resistance: Teflon spray has excellent heat resistance and low temperature resistance.kytfl. Very thin films also show good non-stick properties.

Corrosion resistance: DuPont Teflon is hardly corroded by chemicals, and can protect parts from any kind of chemical corrosion.15. Under a certain load, it has the dual advantages of wear resistance and non-sticking.Product Features: Non-sticky: Almost all materials are not bonded with Teflon spray. It can withstand high temperature to 300°C in a short time, and generally can be used continuously between 240°C and 260°C.05-0. 

Moisture resistance: Teflon spray surface does not PTFE adhesive tape Manufacturers stick to water and oil, and it is not easy to stick to the solution during production operations.If there is a small amount of dirt, simply wipe it off.

It has remarkable thermal stability. Short downtime, saving working hours and improving work efficiency. It can work at freezing temperature without embrittlement and does not melt at high temperature.

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