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 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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