I. Definition:
?it is a kind of braided packing by PTFE fiber, without soaking in PTFE emulsion, or treatment by lubricating oil, therefore it has no other supplements, it is widely used in chemical industry (other than Fluorine gas and alkali metals), pharmacy, food, papermaking, chemical fiber and other industries. It has stable chemical property, well heat resistance, low coefficient of friction, and good wear resistance and so on. But it has some disadvantages as well: it has worse heat conductivity, which will lead to packing leakage because of burning, its thermal expansion coefficient is larger, and therefore, it is easy to creep under certain temperature and pressure, or it may lead to cold-flow and reduce the sealing effect.Actual application comparison of PTFE and other packingLiquid
? ? ?deviceAxle diameter
? ? ?mmRevolution
? ? ?r/minLiquidTemperature
? ?℃Pressure
? ? ?MpaService lifePTFE packingOther seal packing ? ? ? ?
? ? ?Centrifugal pump323600Caustic soda1009.060 daysOil-impregnated asbestos seal packing for 7 days323600Urea130--34 daysOil-impregnated asbestos seal packing for 2～5 days501750Dibutyl ester1002.014 daysPTFE-impregnated asbestos seal packing for 1~5 days341750Nitric acidRoom temperature--210 daysBlue asbestos seal packing for ?14～21days341740Methyl amineRoom temperature7.096 daysBlue asbestos seal packing for 14 days30170045% sulphuric acid77--46 daysPTFE-impregnated blue asbestos seal packing for 7 days301740ChromateRoom temperature4.560 daysBlue asbestos seal packing for 30 days251750Hydrochloric acidRoom temperature4.010 daysBlue asbestos seal packing for 7 daysPluger pump6460/minPhenol14920.060 daysOil-impregnated asbestos seal packing for 14 daysPluger pump5060 /minMethanalRoom temperature50.080 daysOil-impregnated asbestos seal packing for 14 daysValve18--50% sulphuric acid77--210 daysBlue asbestos seal packing for 14~21 daysValve18--sulphuric acid----150 daysAsbestos seal packing for 10daysAutoclave88400Ethylenediamine2004.0720 daysBabbit gasket for 360daysAutoclave3227560% sulphuric acid20050.060 daysPTFE raw material strand for 14daysTECHNIQUE DATACentrifugal ?separatorReciprocating pumpValvePH VALUE0--14LINEAR Vg(M/S)422PRESSURE（Bar）20100200WORKING TEMPERATURE-200CENTIGRADE ~ 260 CENTIGRADEDENSITY：g/cm31.4～1.6P-315-1 PTFE (silica gel cored) packingINCH ″1/83/161/45/163/87/161/25/83/47/81MM356810111216202225KG/M0.080.160.250.380.530.730.931.421.972.663.59
http://www.gasket-china.com/gland-packing/ptfe-fiber-packing/pure-ptfe-fiber-packing.html