Neoprene Lining

D. Test tubes with neoprene lined screw caps 25 mm X 150 mm. 

Appendix A contains a materials selection guide for aerated freshwater systems. As indicated in Note 27 of Appendix A, in freshwater systems, admiralty brass should be limited to a maximum pH value of 7.2 from ammonia and copper-nickel alloys and should not be used in waters containing more sulfides than 0.007 mg/L The materials selection guide is also satisfactory for seawater, although pump cases and impellers should be a suitable duplex stainless steel or nickel-aluminum-bronze (properly heat treated). Neoprene-lined water boxes should be considered. For piping, fiber-reinforced plastic (up to 150 psi [1,035 kPa] operating pressure) and neoprene-lined steel should also be considered. Titanium and high-molybdenum SS tubes should be considered where low maintenance is required or the cost can be justified by life expectancy. 

The lined tanks are cured in situ to achieve good adhesion with metal. Neoprene linings can be cured with air, steam or hot water. Many curing cycles for Neoprene are adopted depending upon the compound type, size and shape of the equipment. 

Typical curing cycles for Neoprene linings are given in Table 6.1. 

PERSONAL PROTECTION wear impervious protective clothing, including rubber boots, neoprene-lined or leather gloves, lab coat, aprons or coveralls wear chemical safety goggles enclose operations and/or use local exhaust ventilation at site of chemical release appropriate respirators are needed in areas where the potential exists for exposures above the permissible exposure level wear self-contained breathing apparatus in unknown concentrations or if concentrations greater than 1000 ppm are expected avoid prolonged exposure to excessive concentrations maintain eyewash baths and safety showers in work area. 

Plastics and Elastomers. Common plastics and elastomers (qv) show exceUent resistance to hydrochloric acid within the temperature limits of the materials. Soft natural mbber compounds have been used for many years as liners for concentrated hydrochloric acid storage tanks up to a temperature of 60°C (see Rubber, natural). SemUiard mbber is used as linings in pipe and equipment at temperatures up to 70°C and hard mbber is used for pipes up to 50°C and pressures up to 345 kPa (50 psig). When contaminants are present, synthetic elastomers such as neoprene, nitrile, butyl. 

Shipment and Storage. Sulfur dichloride, if kept dry, is noncorrosive at ambient temperatures, thus carbon steel and Hon can be used Hi the constmction of tanks, piping, and dmms. However, when water or humidity is present, materials resistant to hydrochloric acid must be used, eg, glass-lined pipe. Teflon, titanium, HasteUoy C, or possibly a chemically resistant, glass-reiaforced polyester. Threaded pipe joHits should be assembled with Teflon tape. Hoses should be constmcted with a Teflon inner lining with the outer tube constmcted of Neoprene or braided 316 stainless steel protected by an adequate thickness of Teflon. Sulfur dichloride should be stored away from heat and away from dHect rays of the sum. Toluene and sulfur dichloride react exothermically when catalyzed by Hon or ferric chloride. Safety precautions should be foUowed when such a mixture is present (165). 

The molded liners for the inlet head, cylinder section, and conical sections have Integral molded gaskets for sealing at the flanged joints. Molded liners and vulcanized linings are offered in gum rubber, polyurethane, nitrile rubber, butyl. Neoprene , Viton , Hypalon , and other liner materials can be supplied. 

Turbines Temper mills Neoprene production lines... 

Chemicals, Chlor alkali. Paper and pulp, Fertilizers, Oil drilling and Pharmaceu ticals Chemical resistant linings for storage tanks, road and ship tankers, process vessels, pipelines, valves, pumps, filters, agitators, centrifuges, impellers, etc. Soft natural rubber or ebonite, neoprene, butyl and hypalon depending on operating temperature, and application. 

Food and Brewing Food quality linings for chutes, hoppers, process vessels, mixers, coating pans, pipelines etc. White natural or neoprene food grade linings of 40 to 60°A. 

Water and Effluent Treatment in Nuclear and other chemical plants. Corrosion resistant linings for water treatment vessels and pipelines, pumps, valves, flowmeters, agitators, chemical dosing tanks, effluent tanks etc. Soft natural rubber or ebonite, EPDM, butyl, neoprene or hypalon. 

These same types of compounds are also more resistant to many acids at high temperatures than natural rubber can handle. Neoprene should not be used in parts which are bonded to metal for hydrochloric acid service because acid migration can cause failures. For hydrochloric acid service ebonite lined mild steel equipment is the correct selection. Ebonites form rubber hydrochloride film in contact with natural rubber and this film is the protective layer against corrosion. 

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