Heat exchangers in sapphire processing

Patent metadata

Field	Value
Publication number	US-9945613-B2
Application number	US-201213623645-A
Country	US
Kind code	B2
Filing date	Sep 20, 2012
Priority date	Sep 20, 2012
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Systems and methods are presented for efficient heating during production of corundum. One embodiment takes the form of a system for processing corundum including a first furnace and a second furnace. The first and second furnaces are sequentially arranged and heat from the first furnace is subsequently used to heat the second furnace.

First claim

What is claimed is:

1. A system for processing corundum, comprising:
a sapphire growth apparatus, comprising:
a first furnace configured to grow a sapphire crystal from a seed material;
a crucible positioned within the first furnace and configured to maintain an orientation of the seed material during a growth of the sapphire crystal; and
an extraction assembly configured to remove the sapphire crystal from the crucible;

a second furnace configured to anneal the sapphire crystal grown by the first furnace by heating the sapphire material to an annealing temperature that is distinct from an operational temperature for the first furnace, the second furnace in communication with, and separated from, the first furnace via an insulated network of piping and comprising a heating element;
a heat battery configured for heat storage; and
a heat exchanger configured for transfer of energy between at least one of:
from the first furnace to the heat battery; or
from the heat battery to the second furnace;

wherein the second furnace is configured to:
receive heat from the first furnace via the heat exchanger and the heat battery to preheat the second furnace; and
use the heating element to achieve the annealing temperature.

2. The system of claim 1 further comprising at least one cooling system, wherein energy extracted from the cooling system is used in at least one of the first or second furnaces.

3. The system of claim 1 wherein:
the heat exchanger is a first heat exchanger configured for transfer of energy between the first furnace and the heat battery; and
the system further comprises a second heat exchanger configured for transfer of energy between the second furnace and the heat battery.

4. The system of claim 1 , wherein the heat exchanger is configured to transfer energy between both of:
from the first furnace to the heat battery; and
from the heat battery to the second furnace.

5. The system of claim 1 , wherein heat from at least one of the first and second furnaces is provided to an additional heat exchanger to heat water or air for heating and ventilation systems.

6. The system of claim 1 , further comprising a central heater configured to provide heat to at least one of the first furnace or second furnace to supplement the heat provided by the first and second furnace.

7. A method of operating multiple furnaces in sapphire processing, the method comprising:
growing a sapphire crystal using a sapphire growth apparatus, the growing including:
maintaining an orientation of a seed material within a crucible; and
heating the crucible using a first furnace operating at a first operational temperature;
growing a sapphire material having a crystal orientation that corresponds to the orientation of the seed material;

transferring heat from the first furnace to a heat battery;
transferring heat from the heat battery to a second furnace; and
annealing the sapphire crystal grown by the sapphire growth apparatus using the second furnace operating at a second operational temperature that is distinct from the first operational temperature.

8. The method of claim 7 , wherein the heat from the first furnace is routed to second furnace in the form of a thermal fluid.

9. The method of claim 8 , wherein the thermal fluid comprises one of water, pressurized steam, alcohol, a solution or molten salts.

10. The method of claim 7 , further comprising:
operating a central heat source; and
routing heat from the central heat source to at least one of the first and second furnaces.

11. The method of claim 7 , wherein the heat from the central heat source is used in preliminary heating of at least one of the first and second furnaces.

12. A heating system for sapphire production, comprising:
a heat battery configured for heat storage;
a plurality of furnaces, a first and a second furnace of the plurality of furnaces configured to sequentially process a sapphire material, each furnace comprising a heat exchanger;
a crucible positioned within one of the plurality of furnaces and configured to maintain an orientation of a seed material during a growth of a sapphire crystal;
an extraction assembly operative to extract the sapphire crystal from the crucible for subsequent processing; and
an insulated network of piping in communication with the heat battery and each of the plurality of furnaces, wherein heat is transferred via the heat exchangers between the heat battery and the plurality of furnaces using the insulated network of piping, wherein:
heat from the first furnace of the plurality of furnaces is used to preheat the second furnace subsequent to the first furnace being heated to and operating at a first operational temperature for the first furnace; and
the second furnace, subsequent to the preheat, is configured to anneal the sapphire crystal formed by the sapphire growth apparatus at a second operational temperature that is distinct from the first operational temperature.

13. The heating system of claim 12 , wherein at least one of the plurality of furnaces comprises an electrical furnace.

14. The heating system of claim 12 , wherein the first furnace is dedicated to heating during a growth phase of sapphire.

15. The heating system of claim 12 , wherein the second furnace is dedicated to heating during a sapphire annealing phase.

16. The system of claim 1 , wherein the sapphire growth apparatus is configured to grow the sapphire crystal using one of the Kyropoulos process, the edge-defined film-fed growth process, or the vertical horizontal gradient freezing process.

Assignees

• Apple Inc

Inventors

• Prest Christopher D
• Memering Dale N

Classifications

• C30B19/08

  Heating of the reaction chamber or the substrate · CPC title

• C30B33/02

  Heat treatment (C30B33/04, C30B33/06 take precedence) · CPC title

• F27B19/04

  arranged for associated working · CPC title

• F27B19/00

  Combinations of different kinds of furnaces that are not all covered by any single one of main groups F27B1/00 - F27B17/00 · CPC title

• F27D17/004 Primary

  Mechanical Engineering · mapped topic