Kettles. These are top loaded vessels designed to apply radiant heat to the vessel’s external surface. Some, supplied with pressure covers, can be used at high pressure. Heating elements radiate uniform heat directly to the outer surface walls of the vessel from which it transfers to the material being heated. Industrial kettles, usually made from welded carbon steel, stainless steel, or copper, and jacketed with high-grade insulation, can support temperatures up to 650°F. All are supplied with appropriate control instrumentation, and some are provided with motor-driven agitators or scraper blades.