FORM 2
THE PATENTS ACT 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
(See section 10 and rule 13)
COMPLETE SPECIFICATION
TITLE: RADIATION CRUCIBLE
NAME: DIPANKAR NATIONALITY: INDIAN
ADDRESS:
EE Department, IIT Bombay, Powai Mumbai 400076
The following specification describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION:
The present invention relates to an apparatus for high temperature operation with minimum energy loss. More particularly, the present invention relates to an apparatus for providing high temperature operations, in excess of 2000° C, like heating, brazing, annealing, incineration, tempering, surface-treatment, sintering, calcinations, etc. as well as melting of metals, ceramics, glasses, etc., with minimum energy loss under vacuum or inert atmosphere.
BACKGROUND OF THE INVENTION:
There have been various crucible or pot furnaces used in the art like electric arc furnaces, cupola furnaces, blast furnaces and induction furnaces. Similarly various types of muffle furnaces are used in the art like electric resistance heating furnace, fuel fired furnace, furnaces using infra red heat source. Using large furnaces such as muffle furnace, induction furnace etc. and utilizing heavy energy loads electrically conductive as well as non conductive materials are melted, heated or calcined in the art. Induction crucible furnaces with vacuum or inert gaseous medium under pressure are preferred for melting metals. One fundamental issue is that a part of the heat generated in the furnace is lost. There are three mechanisms of heat loss from any zone, viz. radiation, conduction and convection. Convection and Conductive processes dominate at lower temperatures. Radiation is the dominant mode of heat transfer at high temperatures, as heat transfer by radiation is proportional to fourth power of Temperature. By the same token at high temperatures, radiative losses dominate. It is therefore imperative to arrest this loss mode at high temperature.
Another shortcoming of many existing furnaces is the maximum temperature rating of the heating elements. Currently the maximum temperature reached in conventional muffle furnaces is limited to approximately 1800° C. The quality of insulation material is also very important at high temperatures, say above 2000°C. The enhanced losses in conventional furnaces also imply use of techniques which may use large cooling devices to remove the heat, thus consuming more energy.

Hence, large losses directly and indirectly result in bulkier equipment, higher capital costs and increased safety risks.
The drawbacks associated with the art as stated above is overcome with the present invention which provides an apparatus for providing high temperature operation, in excess of 2000° C, like heating, brazing, annealing, incineration, tempering, surface-treatment, sintering, calcination, etc. as well as melting of metals, ceramics, glasses, etc., with minimum energy loss under vacuum or inert atmosphere.
OBJECTS OF THE INVENTION:
One of the main objects of the present invention is to provide an apparatus for providing high temperature operations, in excess of 2000° C like heating, brazing, annealing, incineration, tempering, surface-treatment, sintering, calcination, etc. as well as melting of metals, ceramics, glasses, etc., with minimum energy loss under vacuum or inert atmosphere.
It is another object of the present invention to provide an apparatus that consumes less energy for high temperature operations, in excess of 2000° C, including operations like heating, brazing, annealing, incineration, tempering, surface-treatment, sintering, calcination, etc. as well as melting of metals, ceramics, glasses, etc.
It is another object of the present invention to provide an apparatus that reduces radiative losses during high temperature operations.
It is another object of the present invention to provide an apparatus that can operate efficaciously in the entire range of material load capacity.
It is another object of the present invention to provide an apparatus that can operate at high temperatures under vacuum or inert atmosphere.
It is another object of the present invention to provide an apparatus that can operate at high temperatures with high degree of safety.

It is another object of the present invention to provide an apparatus for the operator who can operate at high temperature with high degree of safety.
It is another object of the present invention to provide an apparatus that can operate in very high temperatures.
It is another object of the present invention to provide an apparatus that can operate at high temperatures with minimal capital costs.
SUMMARY OF THE INVENTION:
The present invention relates to an apparatus for providing high temperature operations, in excess of 2000° C, including operations like heating, brazing, annealing, incineration, tempering, surface-treatment, sintering, calcination, etc. as well as melting of metals, ceramics, glasses, etc., with minimum energy loss under vacuum or inert atmosphere. More specifically, the present invention relates to an apparatus incorporating a double walled enclosure having highly reflective surfaces and vacuum that can provide high Temperature operations under vacuum or inert atmosphere with minimum energy loss.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The present invention will be described in more detail hereinafter with the aid of the description which relates to preferred embodiments of the invention explained with reference to the accompanying schematic drawings, in which:
Figure 1 is the radiation crucible.
The following lists reference numerals for attached drawings:
1. Top cover (lid)
2. Crucible
3. Gasket / O-ring
4. Cooling Jacket for outer wall

5. Cooling Jacket for Gasket
6. Inner wall made of highly refractory material which may also be electrically conducting.
7. Highly reflective inner surface of electrically non-conducting outer wall
8. Electrically non-conducting outer wall
9. Insulating material with reflective property inside double walled vacuum region
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT:
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.
The full overview of the arrangement of the invention is shown in Figure 1.
One embodiment of the present invention is the radiation crucible as shown in Figure 1. The apparatus for the hot zone is made up of a Thermos' like - double walled, hollow metallic crucible (2). The crucible has outer wall made of an electrically non-conducting material (8). The crucible has outer electrically non-conducting wall (8) having highly reflecting inner surface (7). The crucible has inner wall (6) made of highly refractory and possibly electrically conducting material like Molybdenum. Graphite, Silicon carbide, Zirconium, or such similar material. There is vacuum or inert atmosphere, in-between the double walled, hollow metallic structure of the crucible. The apparatus for the hot zone made of insulating and highly reflective material (1) is provided with an insulated hollow lid to create an enclosure. The hollow space, present within the double walled structure of the apparatus as well as the insulated lid is evacuated. The lid is tightly fitted on the crucible with a suitable gasket/O-ring for vacuum or inert atmosphere operation for the hot zone. A cooling coil is provided around the

gasket/O-ring (5). The outer wall of the apparatus is provided with a cooling jacket (4). Both the highly reflecting inner surfaces (7) present on the outer wall of crucible and the evacuated hollow lid, radiate the energy back to the hot zone.
The cooling coil (5) around the gasket/O-ring (3) is provided to keep it cool and save it from deformation. The outer wall (8) of the apparatus is provided with a cooling jacket (4) to take away the absorbed radiation energy. The inner-surface of the outer wall (7) of the apparatus is coated with highly reflective (>95% reflectivity) material to reflect the radiative energy back to the source and thus reduce the energy loss. The 'thermos' like double walled evacuated area has insulating and highly reflective material (9) such as Barium sulphate, Magnesium oxide and as the lid is evacuated further enhances reflection of the energy back to the hot zone thus further improving energy efficiency. The radiation crucible having 'thermos1 like double wall vacuum boundary prevents conductive and convective losses.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obvious modifications remain possible, in particular from the point of view of the design of the various elements or by substitution of equivalent methods, without thus departing from the scope of protection of the invention.

I/We claim:
1. A radiation crucible comprising of a hollow insulated lid (1) on the double walled, hollow crucible (2) wherein the crucible and the lid has outer non-conducting wall (8) with highly reflecting inner surfaces (7) made of highly refractory material with a cooling coil (5) around the gasket/O-ring (3) and vacuum or inert atmosphere between outer non-conducting wall (8) and inner wall (6) with a hollow zone made of insulating and highly reflective material (9) whereby high temperature operations in excess of 2000° C, like heating, brazing, annealing, incineration, tempering, surface-treatment, sintering, calcination, as well as melting of metals, ceramics, glasses, or similar material are performed.
2. A double walled radiation crucible (2) with fitted hollow insulated lid (1) as claimed in Claim 1 wherein the outer wall (8) is an electrically non-conducting material having highly reflecting inner surfaces (7) is provided
with a cooling jacket (4) to absorb radiation energy.
3. A double walled radiation crucible (2) as claimed in Claim 1 wherein the inner wall (6) is electrically conducting made of highly refractory material of Molybdenum, Graphite, Zirconium, Silicon carbide or similar material.
4. A double walled radiation crucible (2) and lid (1) as claimed in Claim 1 wherein there is vacuum between outer wall (8) and inner wall (6) of the double walled, hollow crucible and hollow lid.
5. The radiation crucible (2) as claimed in all previous claims wherein the hot zone is provided with a double walled, hollow lid (1) to create an enclosure and the lid is tightly fitted on the crucible with a suitable gasket/O-ring (3) which is surrounded by cooling coil (5) for vacuum or inert atmosphere operation.
6. The radiation crucible (2) and lid (1) as claimed in all previous claims wherein the hollow space present within the double walled structure of the

crucible and the lid is evacuated and is filled with reflective and highly refractory material like Barium sulphate, Magnesium oxide and similar material whereby various high temperature operations are performed.
7. A double walled evacuated radiation crucible (2) and lid (1) as claimed in all previous claims wherein insulating and highly reflective material (9) of the hollow zone reflects the radiation losses back to the hot zone.
8. The radiation crucible (2) is claimed as substantially described herein above and as illustrated in the figures of all accompanying drawings.