Cooling systems

Apparatus for maintaining the temperature of a component below a predetermined maximum temperature, the apparatus comprising a reservoir for a cooling fluid having a boiling point below said temperature, said component and said cooling fluid being in heat transferable juxtaposition to one another such that heat may transfer therebetween, and two heat exchangers associated with said reservoir and operable to effect condensation of vaporised cooling fluid and return same to said reservoir, the heat exchange capacity of at least one of said heat exchangers being variable between maximum and minimum levels, and the combined heat exchange capacity of the heat exchangers when said variable capacity heat exchanger is operating at its minimum heat exchange capacity being sufficient to maintain the temperature of said component below said predetermined maximum temperature and wherein said apparatus is used in a gas turbine engine in which one of said heat exchangers is adapted to effect heat exchange with compressed air derived from a low pressure compressor or fan of the engine and wherein a second one of said heat exchangers is adapted to effect heat exchange with engine fuel.

Apparatus for maintaining the temperature of a component below a predetermined maximum temperature, the apparatus comprising a reservoir for a cooling fluid having a boiling point below said temperature, said component and said cooling fluid being in heat transferable juxtaposition to one another such that heat may transfer therebetween, and two heat exchangers associated with said reservoir and operable to effect condensation of vaporised cooling fluid and return same to said reservoir, the heat exchange capacity of at least one of said heat exchangers being variable between maximum and minimum levels, and the combined heat exchange capacity of the heat exchangers when said variable capacity heat exchanger is operating at its minimum heat exchange capacity being sufficient to maintain the temperature of said component below said predetermined maximum temperature and wherein said apparatus is used in a gas turbine engine in which one of said heat exchangers is adapted to effect heat exchange with compressed air derived from a low pressure compressor or fan of the engine and wherein a further one of said heat exchangers is adapted to effect heat exchange with ambient air drawn from around the engine.

Apparatus for maintaining the temperature of a component below a predetermined maximum temperature, the apparatus comprising a reservoir for a cooling fluid having a boiling point below said temperature, said component and said cooling fluid being in heat transferable juxtaposition to one another such that heat may transfer therebetween, and two heat exchangers associated with said reservoir and operable to effect condensation of vaporised cooling fluid and return same to said reservoir, the heat exchange capacity of at least one of said heat exchangers being variable between maximum and minimum levels, and the combined heat exchange capacity of the heat exchangers when said variable capacity heat exchanger is operating at its minimum heat exchange capacity being sufficient to maintain the temperature of said component below said predetermined maximum temperature and including control means operable to close off communication between one or more of said heat exchangers and said reservoir.

Apparatus for maintaining the temperature of a component below a predetermined maximum temperature, the apparatus comprising a reservoir for a cooling fluid having a boiling point below said temperature, said component and said cooling fluid being in heat transferable juxtaposition to one another such that heat may transfer therebetween, and two heat exchangers associated with said reservoir and operable to effect condensation of vaporised cooling fluid and return same to said reservoir, the heat exchange capacity of at least one of said heat exchangers being variable between maximum and minimum levels, and the combined heat exchange capacity of the heat exchangers when said variable capacity heat exchanger is operating at its minimum heat exchange capacity being sufficient to maintain the temperature of said component below said predetermined maximum temperature and wherein said means to ensure return of condensed cooling fluid comprises pump means and wherein at least one of said heat exchangers projects from the reservoir in a direction different to the other or others.

A method of maintaining the temperature of a component below a predetermined temperature, the method comprising cooling the component by evaporation of a cooling fluid having a boiling point below said temperature, effecting condensation of evaporated cooling fluid by heat exchange with one or more of two heat exchange mediums, the heat exchange capacity of at least one of which is variable between maximum and minimum levels, and maintaining the combined heat exchange capacity of the heat exchange mediums sufficient at all times to maintain the temperature of said component below said predetermined maximum temperature and further including the steps of using the method in a gas turbine engine and wherein one of said heat exchangers exchanges heat with ambient air drawn from around the engine and another one of said heat exchangers exchanges heat with engine fuel.

A method of maintaining the temperature of a component below a predetermined temperature, the method comprising cooling the component by evaporation of a cooling fluid having a boiling point below said temperature, effecting condensation of evaporated cooling fluid by heat exchange with one or more of two heat exchange mediums, the heat exchange capacity of at least one of which is variable between maximum and minimum levels, and maintaining the combined heat exchange capacity of the heat exchange mediums sufficient at all times to maintain the temperature of said component below said predetermined maximum temperature and wherein the method is used with a gas turbine engine and one of said heat exchange mediums is maintained in heat exchange relation with the engine fuel.

A method of maintaining the temperature of a component below a predetermined temperature, the method comprising cooling the component by evaporation of a cooling fluid having a boiling point below said temperature, effecting condensation of evaporated cooling fluid by heat exchange with one or more of two heat exchange mediums, the heat exchange capacity of at least one of which is variable between maximum and minimum levels, and maintaining the combined heat exchange capacity of the heat exchange mediums sufficient at all times to maintain the temperature of said component below said predetermined maximum temperature and wherein a reservoir for said cooling fluid is provided and a control means is provided and including the step of operating said control means to close off communication between said heat exchange mediums and said reservoir.