Gasket material

The mounting cup (ferrule for botde valves) mechanically joins the valve to the container. The mounting cup may be made from a variety of materials, but is typically tin-plated steel coated on the underside. It contains the gasket which provides the seal. Soft gasketing material is appHed wet and bonded in place or, more frequently in larger cans, cut mbber, polyethylene, or polypropylene gaskets are used. 

Polytetrafluoroethylene (PTFE) provides the most satisfactory electrical insulation. Concentric rings of PTFE and PTFE impregnated with calcium fluoride are used for the packing glands which support the anode and cathode posts. Rubber is used as the gasket material to form a seal between the cover... 

Equipment for storing and handling methanol may be made of carbon or stainless steel. Methanol is aggressive toward copper, zinc, magnesium, tin, lead, and alurninum, which should therefore be avoided. Gasket materials must also be chosen carefiiUy, because some elastomers swell and deteriorate when exposed to methanol. Similarly, the use of plastics for storage is not recommended. 

Thiols iateract readily with many mbber-containing materials. For this reason, care should be taken ia the selection of gasket and hose materials. Teflon, Kel-F, Viton, or other suitable fluoroelastomers function as gasket materials. Viton is suitable for hoses. Carbon steel is useful for many thiols, although some thiols become very discolored when carbon steel is utilized. In these cases, the use of stainless steel is very desirable. Isolation from air and water also minimizes color formation. 2-Mercaptoethanol and 1,2-ethanedithiol should be stored ia stainless steel (61). 

Demountable joints are commercially available in great variety in stainless steel, but less so in aluminum alloy or related materials. Experimental joints have been made in which aluminum flanges employ aluminum foil as gasket material. 

R. A. Mercuri, R. A. Howard, and J. J. McGl meiy, Ndranced High Temperature Test Methodsfor Gasket Materials, Automotive Eng 97, 49—52 (July 1989). 

The Hquid polymer is then compounded with metal oxides or peroxides, as weU as fillers (carbon black) and can undergo cold vulcanization, ie, chain extension and cross-linking iato a soHd matrix. It is largely used as a sealant and gasket material for wiadows, automobile wiadshields, etc. 

TFE composites To 500 Chemical and heat resistance comparable with solid TFE. Inner gasket material provides better resiheucy and deformabdity. 

TABLE 28-28 Important Properties of Gasket Materials Concluded)... 

Rubber (straight) To 600 See Gasket Materials for properties. Mainly used for ring-type seals, although some types are available as spiral packings. 

Gasket materials Metal jacketed or solid metal for (a) internal floating head cover. (b) 300 psi and up. (c) all hydrocarbons. Metal jacketed or solid metal (a) internal floating head. (b) 300 psi and up. Asbestos permitted for 300 psi and lower pressures. (same as TEMA C)... 

Tray gasketing material blocking downcomer. Same as item 21. 

Bays in Parallel in Series Gasket Material Pitch in. A... 

Gasket Material Max. Operating Temp., °F Compatible Fluids... 

Table 26.1 Gasket materials, operating temperatures and applications...

Gasket material Approx, maximum operating temp. °C °F Application... 

Flange face areas experience stagnant conditions. Additionally, some gasket materials, such as asbestos fiber, contain leachable chloride ions. This creates crevice and stress corrosion cracking problems on sealing surfaces. Where necessary, flange faces that are at risk can be overlaid with nickel-based alloys. Alternatively, compressed asbestos fiber gaskets shrouded in PTFE may be used. 

In this method of jointing stoneware piping, the joint is formed by a gasket between ground ends of the pipe, the joint being put under compression by a metal clamp. The choice of gasket material will of course depend upon service conditions. 

Bag filters are perhaps the most widely used of these types of pretreatment equipment, and they are also commonly employed (and highly recommended) for sidestream application in HW boiler circuits. They are reliable and robust and tend to be available in an almost infinite number of permutations. When sizing, specification items to be considered include flow rates, vessel materials, housing and support-basket sizes, pipe sizes, connection threads and flanges, outlet positions, code and pressure ratings, gasket materials, bag shapes, bag materials, and micron ratings. 

Reactor material Silicon Pyrex Gasket material Kalrez hybrid Kalrez /graphite... 

Reactor type Multiphase packed-bed reactor Gasket material Viton... 

Plates are available in a wide range of metals and alloys including stainless steel, aluminium and titanium. A variety of gasket materials is also used see Table 12.8. 

Table 12.8. Typical gasket materials for plated heat exchangers...

The maximum operating temperature is limited to about 250 °C, due to the performance of the available gasket materials. 

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