Heat dissipation from ACB toes

1. A heat dissipation apparatus for an air circuit breaker (ACB) switchgear having at least one pair of primary contact toes constructed and arranged to connect to a terminal of the circuit breaker, with a bus bar joint being connected to the primary contact toes, the heat dissipation apparatus comprising:

an evaporator clamped to the primary contact toes, a condenser located at a higher elevation than the evaporator, at least two electrically isolating pipes fluidly connecting the evaporator with the condenser, and a dielectric fluid in the evaporator adapted to be heated to a vapour state, with one of the pipes being constructed and arranged to transfer the vapour to the condenser and the second pipe being arranged to return the condensed dielectric fluid back to the evaporator for cooling the at least one pair of primary contact toes, the dielectric fluid being non-hazardous (UL listed), chemically stable, suitable for two phase applications, have a crucial temperature −200° C. and chemically compatible with copper and a dielectric and UL listed material, wherein the evaporator is manufactured from a single solid block of metal and has an internal fluid path for the dielectric fluid that is defined by cross-hatched channels fabricated by drilling partially through the evaporator block from a top side to one side.

2. A heat dissipation apparatus as claimed in claim 1 , wherein the condenser includes a plurality of fins in spaced relation, with the fins being arranged to transfer heat from the condenser to surrounding air by natural convection.

3. A heat dissipation apparatus as claimed in claim 2 , wherein the fins of the condenser are metal and disposed substantially parallel to one another.

4. A heat dissipation apparatus as claimed in claim 1 , in which the condenser is generally flat and includes a tubular arrangement of an elongate pipe formed into a plurality of U-shaped formations arranged to provide a thermosyphon effect for the efficient cooling of the dielectric fluid in the condenser.

5. A heat dissipation apparatus as claimed in claim 1 , in which the evaporator is manufactured from copper or aluminum and has an internal fluid path for the dielectric fluid.

6. A heat dissipation apparatus as claimed in claim 5 , in which the evaporator is clamped to the primary contact toes by means of at least one nut and bolt extending through an orifice in the evaporator.

7. A method of dissipating heat from an air circuit breaker (ACB) switchgear having at least one primary pair of contact toes constructed and arranged to connect to the terminal of a circuit breaker, with a bus bar joint being connected to the primary contact toes, the method comprising the steps of:

clamping an evaporator to the primary contact toes, providing a condenser located at a higher elevation than the evaporator;

providing at least two electrically isolating pipes fluidly connecting the evaporator with the condenser;

providing a dielectric fluid in the evaporator, the dielectric fluid being non-hazardous (UL listed), chemically stable, suitable for two phase applications, have a crucial temperature −200° C. and chemically compatible with copper and a dielectric and UL listed material; and

transferring heat from the primary contact toes to the dielectric fluid to cause the dielectric fluid to evaporate in the evaporator with the evaporated vapour being delivered to the condenser via one of the pipes and returning the dielectric fluid that condenses in the condenser back to the evaporator via the second pipe, wherein the evaporator is manufactured from a single solid block of metal and has an internal fluid path for the dielectric fluid that is defined by cross-hatched channels fabricated by drilling partially through the evaporator block from a top side to one side.

8. A method of dissipating heat from an air circuit breaker (ACB) switchgear as claimed in claim 7 , in which the condenser includes a plurality of fins in spaced relation, with the fins being arranged to transfer heat from the condenser to surrounding air by natural convention.

9. A method for dissipating heat from an air circuit breaker (ACB) switchgear as claimed in claim 8 , in which the fins of the condenser are metal and disposed substantially parallel to one another.

10. A method of dissipating heat from an air circuit breaker (ACB) switchgear as claimed in claim 7 , in which the air condenser is generally flat and includes a tubular arrangement of an elongate pipe formed into a plurality of U-shaped formations arranged to provide a thermosyphon effect for the efficient cooling of the dielectric fluid in the condenser.

11. A method of dissipating heat from an air circuit breaker (ACB) switchgear as claimed in claim 7 , the evaporator is manufactured from copper or aluminum and has an internal fluid path for the dielectric fluid.

12. A method of dissipating heat as claimed in claim 11 , characterized by clamping the evaporator to the primary contact toes by means of at least one nut and bolt extending through an orifice in the evaporator.