Inhibiting corrosion in aqueous heat transfer apparatus

Abstract From the Canadian patent

Aqueous heat transfer apparatus contains a multicomponent corrosion protection system including a first component adapted to release a corrosion inhibitor on exposure to water under relatively milder conditions and a second component adapted to release a corrosion inhibitor on exposure to water under relatively severer conditions. The components may be open top compartments, 2, 3, of a capsule, 1, (Figure 1) which includes lugs 6 to bear against and grip the inside of a passage in which the capsule is located. The open tops of the compartments are closed by means of covers of controlled release glass which dissolve in water at different rates.