Conveyors: fluid current – Having means for maintaining load in suspension along flow path – By load supporting jets
Reexamination Certificate
1999-08-12
2002-01-08
Ellis, Christopher P. (Department: 3651)
Conveyors: fluid current
Having means for maintaining load in suspension along flow path
By load supporting jets
C406S051000, C198S721000, C414S676000, C432S239000
Reexamination Certificate
active
06336775
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas floating apparatus which floats, with a gas, an object as a material to be treated such as a raw material, a part or an intermediate product which is for the production process of a final product such as a plasma display panel or a solar battery panel; a gas floating-transporting apparatus which floats and transports such an object; and a thermal treatment apparatus which thermally treats such an object as well as a gas floating method which floats an object as a material to be treated; a gas floating-transporting method which floats and transports such an object and a thermal treatment method of such an object.
2. Related Art
Various thermal treatments such as heating and cooling treatments are used in production processes of various products. Concretely, a number of effects are known which are provided by drying, firing, seal-bonding, evacuation, annealing and other thermal treatments.
For example, it has been proposed to transport materials to be treated using a mesh conveyer belt, a roller hearth or the like so as to thermally treat them by passing them through a heating furnace in the form of a dome or a tunnel in order to improve effectiveness of the thermal treatment.
A thermal treatment apparatus of a mesh belt transport type with electric resistive heating which is generally used for the production of electronic parts is schematically shown in
FIG. 19
in a perspective view. In the thermal treatment apparatus
1100
, a mesh belt
1106
moves continuously in one direction through a tunnel made of a metal material, and the tunnel is called a heating muffle
1104
which is surrounded by electrically resistive heating blocks
1102
. The material to be treated
1108
is moved from a loading side (or a loader)
1110
to an unloading side (or an unloader)
1112
while being supported on the mesh belt
1116
. The material to be treated
1108
is heated at a predetermined temperature while it is passed through the heating muffle
1104
. After the mesh belt
1106
and the material to be treated
1108
have passed through the zone surrounded by the heating blocks
1102
, they are cooled while passing through a cooling muffle
1116
which is equipped with a cooling pipe
1114
.
In the heating furnace used for the purpose of the thermal treatment, there are generally provided, along a transporting direction of the material to be treated, a temperature elevating zone where the material to be treated is heated, a temperature keeping zone where the heated material to be treated is kept at the elevated temperature, and a temperature decreasing zone where the temperature of the material to be treated is lowered, whereby the material is thermally treated as predetermined while it passes through those zones in turn. Usually, an amount of heat is added in the temperature elevating zone, and an amount of heat corresponding to heat loss is added in the temperature keeping zone while heat is removed in the temperature decreasing zone.
As a heater used in the heating furnace for the thermal treatment of the electronic parts, there are electrically resistive heating by means of an electric energy, image heating by means of lump irradiation, heating by means of combustion heat through burning of for example gas fuel, and these heaters can be used alone or in combination. In order to keep the thermal treatment condition which is stable and not affected by the heat load of, for example, the materials to be treated, a thermal treatment space comprising an atmosphere of which heat capacity is large is required to be formed. Thus, internal structures of the thermal treatment apparatus which form the thermal treatment space also have to be heated using the above heating manner.
In the conventional thermal treatment manner as described above, when all the materials to be treated are uniformly heated, kept at their temperatures and cooled during their thermal treatment, a large thermal treatment space is required, and thus a heat energy loss by means of such a thermal treatment space is also very large. In order to keep such a large thermal treatment space, there is a problem in that a ratio of a heat energy which has been effectively consumed by the materials to be treated through the heating treatment (i.e. effectively reserved heat) to a heat energy which has been supplied to the thermal treatment apparatus is small, so that most of the supplied heat energy is wasted, which leads to a high cost of the thermal treatment.
As described above,
FIG. 19
schematically shows a partly cut-away perspective view of a usual thermal treatment apparatus of the mesh belt transportation type which is used for the thermal treatment of the electronic parts and the like, and the inside of the apparatus can be seen. For example, the following reasons why a heat energy utilization efficiency of such an apparatus is law can be conceived:
A heat balance sheet of a conventional thermal treatment apparatus is shown in FIG.
20
. The calculation of the heat balance is based on an amount actually being supplied to the thermal treatment apparatus corresponding to 100%. With a typical heating furnace of the tunnel type through which a conveyer for the materials to be treated moves, since an inlet and an outlet of the apparatus are always open, a portion of the heat supplied to the heating furnace escapes from the outlet and the inlet. An amount of such escaping heat would be as much as about 30% of the supplied total heat energy.
Further, in the thermal treatment apparatus, the conveyer in addition to the materials to be treated has to be heated, so that a large amount of heat is consumed for heating the conveyer. In order to heat the conveyer which is of a complicated mechanism and of which heat capacity is large, a large amount of heat is required. When the conveyer leaves the heating furnace, an amount of heat supplied to the conveyer in the thermal treatment apparatus dissipates to the outside so that such heat is wasted. Every time when the conveyer recirculates to enter and leave the thermal treatment apparatus during its circulation, a large amount of heat is added to the conveyer and such an amount dissipates to the outside without being utilized. The heat loss by means of the conveyer would be as much as about 20% of the supplied total heat energy.
In addition, with the conventional thermal treatment technology, an amount of heat energy lost outside through a wall of the heating furnace is large, which would be as much as about 45% of the supplied total heat energy.
As a result, it is said that only not more than 5% of the totally supplied energy is used for the thermal treatment of the material to be treated, and thus very ineffective thermal treatment is currently carried out.
Throughout the present specification, the term “thermal treatment” means a treatment of temperature increasing, temperature maintaining, temperature decreasing, or any combination thereof of the material to be treated. Thus, for the purpose of the thermal treatment, heat may be added to the material to be treated or heat may be removed from the material to be treated, or any combination thereof may be possible (optionally thermal insulation may be included). By means of such thermal treatment, at least one property of the material to be treated (for example, a water content, a weight, an electric resistance, a permeability, a thickness of a resulted film or its uniformity, an internal stress or strain, a strength, a composition or the like) is changed as predetermined.
For example, the treatment in which an amount of heat is added to the material to be treated includes a treatment in which the material to be treated is heated to a predetermined temperature in a predetermined period, a treatment in which the material to be treated is kept at a predetermined temperature for a predetermined period, and a treatment in which the material to be treated is subjected to a predetermined temperature changing condition. Further, the treatment in which an amoun
Morita Makoto
Tanimoto Kenji
Tsutsui Yuji
Yokoyama Nobuhito
Yoshida Masaru
Dillon, Jr. Jae
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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