Oil cooler

摘要

An oil cooler comprises a heat exchanger through which the oil passes and which is cooled by a fan. The fan is provided with variable pitch blades so that a variable flow rate of cooling air may be directed on to the heat exchanger. The pitch of the blades is controlled by a piston and cylinder assembly which is actuated by a viscous restrictor located in the oil flow path to the heat exchanger. The arrangement is such that the flow rate of cooling air increases with any decrease in the pressure drop across the viscous restrictor and vice versa.