Pressure chemical resistance

A process diffuse reflectance probe that works in contact with the sample, is available from Hellma GmbH Co KG. The Model 661.761.NIR probe has seven 200 /rm diameter illumination fibers illuminating the sample at a 30" angle, and one 600 / m diameter core pickup fiber at the center of the illumination fibers. The DN 25/PN40 standard flange mounted probe withstands a temperature ranging from 5 to 140°C and 10 bar pressure. Chemical resistance can be enhanced with the Hastelloy C-22 body (Figure 37.40). 

PVA fiber is best fit for reinforcement of oil brake hoses for cars that require high reUabiUty, because of excellent mechanical properties and good chemical resistance to pressure—transmission Hquid contained in the hose. 

Most metals, concrete, and other constmction materials are corroded by hydrobromic acid. Suitable materials of constmction include some fiber glass-reinforced plastics, some chemically resistant mbbers, PVC, Teflon, polypropylene, and ceramic-, mbber-, and glass-lined steel. Metals that are used include HasteUoy B, HasteUoy C, tantalum, and titanium. The HasteUoys can only be used at ambient temperatures. Liquid hydrogen bromide under pressure in glass at or above room temperature can attack the glass resulting in unexpected shattering. 

Storage and Handling. The acid should never be allowed to stand in a line completely sealed between two closed valves or check valves. Excessive pressure caused by thermal expansion of the Hquid can cause leaks or pipe mptures. AH lubricants and packing materials in contact with chlorosulfuric acid must be chemically resistant to the acid. Elanged connections are recommended over screwed fittings and flange guards should be used. 

The development of the mechanical seal advanced in parallel with elastomer technology. Mechanical seals using o-rings and other elastomer forms, benefited with improved shelf-life, maximum and minimum temperature limits, better chemical resistance, and higher pressure ratings. 

About half of all pumps in the shop today were pulled out of service because they were leaking or wouldn t hold pressure or pump. This is most likely a leaking o-ring. The o-ring is the rubber component of most mechanical seals. The o-ring controls the temperature, pressure, and chemical resistance of the mechanical seal (Figure 14-1). 

The chemical resistance of PTFE is almost universal It resists attack by aqua regia, hot fummg nitnc acid, hot caustic, chlorine, chlorosulfonic acid, and all solvents. Despite this broad chemical resistance, PTFE is attacked by molten alkali metals, ammonia solutions of such metals, chlorine trifluoride, and gaseous fluonne at elevated temperature and pressure PTFE swells or dissolves m certam highly fluonnated oils near its melting point. Specific lists of chemicals compatible with PTFE are available [/.8]... 

Verheijen, J., Bongaerts, P., and Verspui, G., Low Pressure Chemical Vapour Deposition of Temperature Resistance Colour Filters, Proc. 10th. Int. Conf. on CVD, (G. Cullen, ed.), pp. 977-981, Electrochem. Soc., Pennington, NJ 08534 (1987)... 

Corrosive wear results from a chemical reaction of the wear surface with the environment. In this section, only corrosion that occurs in conjunction with mechanical wear is considered. Purely corrosive wear is reviewed in Sec. 4.0 below. The chemical resistance of a given coating material must be assessed if the application involves a corrosive environment. A typical example is the environment found in deep oil and gas wells (over 500 m.), which usually contain significant concentrations of CO2, H2S, and chlorides. The corrosive effect of these chemicals is enhanced by the high temperature and pressure found at these great depths. 

Cubic boron nitride is obtained from hexagonal boron nitride at high pressure and temperature in the presence of lithium nitride as a catalyst. It is almost as hard as diamond and has superior chemical resistance and a much higher oxidation threshold.Efforts to... 

S-layer ultrafiltration membranes (SUMs) are isoporous structures with very sharp molecular exclusion limits (see Section III.B). SUMs were manufactured by depositing S-layer-carrying cell wall fragments of B. sphaericus CCM 2120 on commercial microfiltration membranes with a pore size up to 1 pm in a pressure-dependent process [73]. Mechanical and chemical resistance of these composite structures could be improved by introducing inter- and intramolecular covalent linkages between the individual S-layer subunits. The uni-... 

Level A protection should be worn when the highest level of respiratory, skin, eye, and mucous membrane protection is needed. This level consists of a fully-encapsulated, vapor-tight, chemical-resistant suit, chemical-resistant boots with steel toe and shank, chemical-resistant inner/outer gloves, coveralls, hard hat, and self-contained (positive pressure) and SCBA. 

Fire Tabun reacts with steam and water to produce toxic and corrosive vapors. Any personnel not fighting a fire of sarin should immediately be evacuated from the area. Respiratory protection is required (positive pressure, full face piece, NIOSH-approved SCBA will be worn). When response personnel respond to handle rescue or reconnaissance, they will wear Level A protection that should be worn when the highest level of respiratory, skin, eye, and mucous membrane protection is needed. This level consists of a fully-encapsulated, vapor-tight, chemical-resistant suit, chemical-resistant boots with steel toe and shank, chemical-resistant inner/outer gloves (butyl rubber glove M3 and M4 Norton, chemical protective glove set), coveralls, hard hat, and self-contained (positive pressure) breathing apparatus (SCBA). 

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