HEAT EXCHANGERS

A heat exchanger for cooling a fluid in a flow path and containing a component liable to phase change below a temperature thereof comprises a series of tubes for the passage of coolant and an injector for introducing an anti-freeze component into the fluid in the flow path. The injector is an antifreeze injector, such as a methanol injector arranged for connection to a source of methanol. The antifreeze injector comprises a plurality of injection portions and is arranged to inject a more concentrated antifreeze at a first injection portion in a first region of air flow and a more water-diluted antifreeze at a second injection portion which is more upstream than the first injection portion at a second region of air flow that is warmer than the first region.