Chemical and petrochemical industries often require pumps to handle liquids at high temperatures. High temperature in the industrial practice means the temperature that range from 100 o C to as high as 350 o C.
High temperature operation also incidentally has to address the high vapour pressure of the liquids handled. Oxidation when it encounters atmospheric oxygen resulting in coking, formation of inflammable vapours, at times formation of explosive mixtures with atmospheric oxygen.
Materials of Construction: Wetted end parts are selected with due consideration of high temperature, strength and corrosion resistance.Bearing Selection: Antifriction bearings are carefully selected with appropriate clearance class to ensure that bearings run smooth even at elevated temperatures. Mechanical seals: Seal is provided with appropriate venting and flushing with cooled liquid (If so deemed necessary) applying Plan 11. This ensures that the seal chamber is maintained at a pressure slightly higher than suction pressure and ensures margin over the boiling point and avoids vapour formation and of course serves to carry away heat generated in the chamber. Plan 62 if so required provides for air blanketing, and dilution of trace leaks of the liquid. On specific demand, Superflow pumps are provided with water cooling for the centreline supports to avoid linear rise of supports due to convective heating from hot casing. Welded jackets or steam tracing tubing with heat transfer cement is provided on the casing to ensure that the casing is maintained close to operating temperature to avoid sudden heat stress at start-up of the pump. Needless to say, these pump casings have to be insulated with Mineral wool, encased in a easily openable aluminium casing.
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