Factors important in designing a cathodic protection system for glass lined domestic hot water heaters are considered. Method by which bare areas of single coated glass lined tanks can be calculated is explained, and comparisons are made between calculated values and those obtained by tests on tanks under protection. Instruments for making these tests and techniques are illustrated and described.
Design data relevant to required current densities are considered with respect to platinum clad tantalum and platinum plated titanium anodes. Regulations of Underwriters’ Laboratories concerning accumulated gas from cathodic protection systems are weighed against test results and the volume of gas actually produced is measured and analyzed.
Design criteria and details for rectified current used in systems applied to electrically heated tanks are given. Details of a thermoelectric generator for use with gas fired tanks are given. This generator produces sufficient current to protect a well-lined tank in the highest resistivity water likely to be encountered. 5.2.3
