Metal founding – Means to shape metallic material – Including means to heat mold
Reexamination Certificate
1999-05-04
2001-03-27
Pyon, Harold (Department: 1722)
Metal founding
Means to shape metallic material
Including means to heat mold
C164S350000, C164S352000
Reexamination Certificate
active
06206081
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for solidifying a casting to create a directionally solidified or single crystal casting and, more particularly, to an apparatus which is capable of introducing a cooling spool into a casting mold and withdrawing the casting mold from a stationary heating chamber.
2. Related Art
Solidifying molten materials, such as molten metal, in a mold cavity to create a directionally solidified or single crystal casting is known.
FIGS. 1
a
and
1
b
illustrate a conventional apparatus
10
for producing a casting. An example of this is disclosed in U.S. Pat. No. 4,969,501. The apparatus
10
includes a heating chamber
12
defining an interior volume
16
which is heated via heating elements
14
. A plurality of casting molds
20
are disposed in an annular array on a vertically movable chill plate
22
. The molds are supported in and removable from the interior volume
16
by the movable plate
22
. The movable plate
22
is vertically displaced by column
24
. More particularly, the casting molds
20
may be removed from the interior volume
16
by displacing the plate
22
in the direction of arrow A (
FIG. 1
b
) while the heating chamber
12
remains stationary.
Unfortunately, apparatus
10
produces directionally solidified or single crystal castings having less desirable material properties due to a lower thermal gradient during casting. A thermal baffle or heat sink is not introduced into an interior region of the casting mold apparatus during the withdrawal from the heating chamber
12
to selectively absorb radiant heat being supplied from the molds
20
. Indeed, order to obtain a directionally solidified or single crystal casting, a casting mold must be removed from a heating chamber using special procedures.
FIGS. 2
a
and
2
b
show another conventional apparatus
50
to produce a directionally solidified or single crystal casting. An example of this is disclosed in U.S. Pat. No. 5,778,961. The apparatus
50
includes a heating chamber
12
defining an interior volume
16
for receiving an annular array of casting molds
20
. The casting molds
20
surround and define an interior space
21
. The molds are disposed on a chill plate or disk
30
which includes a central aperture
31
. A thermal baffle or heat sink
34
is shaped and sized to pass through the aperture
31
in the plate
30
, and the baffle is movable vertically upward in the direction of arrow C (
FIG. 2
b
) with respect to the plate
30
by its supporting column
36
. In particular, the thermal baffle
34
may be moved into the interior space
21
by moving the column
36
upward, and vice versa. The radiation baffle
19
is disposed below the open end of the heating chamber
12
.
The casting molds
20
are maintained in a substantially fixed position and height with respect to a floor
32
. The casting molds
20
are removed from the interior volume
16
of the heating chamber
12
by raising the heating chamber
12
in the direction of arrow B (
FIG. 2
b
). Thermal baffle
34
may be moved into interior space
21
while the heating chamber
12
is moved.
Apparatus
50
is also less desirable for preparing directionally solidified or single crystal castings because the heating chamber
12
must be lifted away from the casting molds
20
while the molds
20
are fixed in height and position with respect to floor
32
which is contrary to industry practice. The investment casting industry more widely accepts withdrawal processes in which the casting molds
20
are moved downward out of the heating chamber
12
, and would be unable to retrofit existing furnaces to provide a heating chamber
12
which must be lifted.
Accordingly, there is a need in the art for a directionally solidified or single crystal casting apparatus which allows for withdrawing casting molds from a substantially fixed heating chamber.
SUMMARY OF THE INVENTION
In order to overcome the disadvantages of the prior art, the casting apparatus of the present invention includes a substantially stationary heating chamber having an upper pouring opening and a substantially open lower end. An outer cooling spool is disposed at the periphery and the open lower end of the heating chamber. A chill plate having an aperture therethrough is movable through the lower end of the heating chamber from the lower end of the chamber to below that end.
A mold assembly is receivable into the lower end of the heating chamber. The assembly includes at least one, and typically includes an annular array of a plurality of peripherally disposed mold cavities disposed on the chill plate.
An inner cooling spool is movable through the aperture of the chill plate and the open lower end of the mold assembly. A first actuator vertically displaces the chill plate and the mold assembly with respect to the heating chamber. A second actuator vertically displaces the inner cooling spool with respect to the heating chamber.
Other objects, features, and advantages of the casting apparatus of the present invention will become apparent to those skilled in the art in view of the description below taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3810504 (1974-05-01), Piwonka
patent: 3897815 (1975-08-01), Smashey
patent: 4178986 (1979-12-01), Smashey
patent: 4969501 (1990-11-01), Brokloff et al.
patent: 5778961 (1998-07-01), Hugo et al.
patent: 5931214 (1999-08-01), Spicer et al.
Chiang Feng
Peterson Omer Carl
Bittman Mitchell D.
Chromalloy Gas Turbine Corporation
Faber Robert C.
Lin I.-H.
Pyon Harold
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