Patent Publication Number: US-6698493-B2

Title: Apparatus and method for casting a metal article

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus and method which are used in the casting of a metal article. During withdrawal of a mold for the metal article from a heating chamber of a furnace, a baffle blocks transmission of heat from the heating chamber. 
     It has been previously been suggested to utilize a baffle to block transmission of heat from a heating chamber of a furnace during withdrawal of a mold from the heating chamber. The use of the baffle minimizes the loss of heat from the heating chamber so that the heating chamber remains at a relatively high temperature and the space below the heating chamber is maintained at a relatively low temperature. This temperature differential promotes solidification of molten metal from a lower end portion of the mold toward an upper end portion of the mold as the mold is withdrawn from the heating chamber. 
     It has previously been suggested that baffles may be utilized in association with molds to retard the transmission of heat from a heating chamber of a furnace. Various baffle constructions which have previously been suggested are disclosed in U.S. Pat. Nos. 4,108,236; 4,774,992; 4,969,501; and 6,276,432. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a new and improved apparatus and method for use in casting a metal article. The apparatus may include a furnace assembly having a heating chamber. A chill plate may be provided to move a mold into and out of the heating chamber. A baffle may be utilized at a lower end portion of the heating chamber to at least partially block heat flow from the heating chamber during withdrawal of the mold from the heating chamber. 
     The baffle may have an inner section with an opening through which the mold extends when the mold is in the heating chamber. An outer section of the baffle may extend around the inner section of the baffle. A plurality of connectors may extend between the outer and inner sections of the baffle and hold them against movement relative to each other. The connectors may be releasable to enable the inner section of the baffle to move downward relative to an outer section of the baffle to increase the size of an opening through which the mold moves from the heating chamber. 
     The connectors may extend between the outer and inner sections of the baffle and retain one or more side surfaces on the outer and inner sections of the baffle in a coplanar relationship when the mold is in the heating chamber of the furnace assembly. The connectors may be releasable under the influence of force transmitted from the mold to enable the inner section of the baffle to move downward relative to the outer section of the baffle. 
     The baffle may be formed as one-piece with the connectors integrally formed as one-piece with the outer and inner sections of the baffle. The connectors may be broken under the influence of force transmitted from the mold to the baffle during lowering of the mold from the heating chamber. If desired, the outer and inner sections of the baffle may be separated by a plurality of slits with the connectors disposed between end portions of the slits and formed of the same material which forms the outer and inner sections of the baffle. 
     The outer and inner sections of the baffle may be formed as separate pieces. If this is done, the inner section of the baffle may initially be disposed in an opening in the outer section of the baffle and held in its initial position by a plurality of connectors which extend between the outer and inner sections of the baffle. The connectors are releasable to enable the inner section of the baffle to move downward out of the opening in the outer section of the baffle as the mold is moved from the heating chamber of the furnace assembly. 
     The inner section of the baffle may be disposed above and at least partially supported by the outer section of the baffle. If this is done, the inner section of the baffle may be moved downward through an opening in the outer section of a baffle to increase the size of an opening through which the mold is moved from the heating chamber. 
     Although the baffle may be connected with a furnace assembly in many different ways, it is believed that it may be desired to utilize latches to connect the baffle with the furnace assembly. The outer section of the baffle may be moved into engagement with and move the latches during movement of the baffle into the heating chamber in the furnace assembly. The latches are effective to retain the outer section of the baffle against downward movement relative to the furnace assembly during movement of the mold out of the heating chamber in the furnace assembly. 
     The present invention has a plurality of different features which may be used together or separately. One or more of the features of the present invention may be utilized in association with one or more features of the prior art. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG.  1 . is a schematic illustration depicting a relationship of a baffle to a furnace assembly having a heating chamber in which a mold is disposed; 
     FIG.  2 . is a schematic plan view, taken generally along the line  2 — 2  of FIG. 1, further illustrating the construction of the baffle; 
     FIG.  3 . is a schematic fragmentary sectional view, taken generally along the line  3 — 3  of FIG. 2, illustrating a slit which is formed in the baffle and separates an outer section of the baffle from an inner section of the baffle; 
     FIG.  4 . is a fragmentary sectional view, taken generally along the line  4 — 4  of FIG. 2, schematically illustrating the construction of a connector which extends between the outer and inner sections of the baffle; 
     FIG.  5 . is a fragmentary schematic illustration, generally similar to FIG. 4, depicting an alternative construction of the connector which interconnects the inner and outer sections of the baffle; 
     FIG.  6 . is a fragmentary schematic illustration, generally similar to FIGS. 4 and 5, illustrating a baffle having an inner section which is separate from an outer section and the manner in which a connector retains the inner section of the baffle in an opening in the outer section of the baffle; 
     FIG.  7 . is a fragmentary schematic sectional view, generally similar to FIGS. 4-6, illustrating the manner in which adhesive may be utilized to retain a inner section of the baffle in an opening in an outer section of the baffle; 
     FIG.  8 . is a schematic sectional view, generally similar to FIGS. 4-7, illustrating the manner in which a connector member and adhesive may be utilized to hold the inner section of the baffle in an opening in the outer section of the baffle; 
     FIG.  9 . is a schematic plan view, generally similar to FIG. 2, illustrating the manner in which breakable members may be utilized to hold an inner section of a baffle in an opening in an outer section of the baffle; 
     FIG.  10 . is a fragmentary schematic illustration, generally similar to FIG. 1, depicting the manner in which an inner section of a baffle may be disposed above an outer section of a baffle; 
     FIG.  11 . is a enlarged schematic illustration depicting the manner in which an outer rim portion of the inner section of the baffle of FIG. 10 is supported by an inner rim portion of the outer section of the baffle; 
     FIG.  12 . is a fragmentary schematic illustration, generally similar to FIGS. 1 and 10, illustrating the manner in which latches may be utilized to retain an outer section of any one of the baffles of FIGS. 1-11 against downward movement relative to a furnace assembly; 
     FIG.  13 . is a schematic illustration of one of the latches of FIG. 12; and 
     FIG.  14 . is a schematic illustration of a second embodiment of a latch which may be utilized to hold a baffle against downward movement relative to a furnace assembly. 
    
    
     SPECIFIC PREFERRED EMBODIMENTS OF THE INVENTION 
     General Description 
     An apparatus  20  (FIG. 1) is used to cast a blade or vane for a turbine engine. However, it should be understood that the apparatus  20  may be utilized to cast many different articles having many different configurations other than the specific configuration illustrated in FIG.  1 . The apparatus  20  includes a furnace assembly  22 . 
     The illustrated furnace assembly  22  is of the known induction type and includes a cylindrical induction coil  24 . The induction coil  24  extends around a refractory wall  26  of the furnace assembly  22 . A cylindrical radiation liner  28  is provided within the refractory wall  26 . A circular cover  30  is provided at the upper end portion of the refractory wall  26 . 
     The furnace assembly  22  may be enclosed by a housing. Once a mold  34  has been positioned in the housing on a circular chill plate  36 , an inert atmosphere may be provided in the housing and the housing may be evacuated. The housing may have the same general construction as is disclosed in U.S. Pat. No. 3,841,384. If desired, a fluidized bed and/or housing may be utilized in the manner disclosed in U.S. patent application Ser. No. 09/569,906 filed May 11, 2000 by Graham et al and entitled System For Casting A Metal Article Using A Fluidized Bed. The disclosure from the aforementioned U.S. patent application Ser. No. 09/569,906 is incorporated herein by reference. 
     When the mold  34  is to be utilized to cast a metal article, such as a turbine engine blade or vane, the cast metal article may be formed of a nickel-chrome super alloy. Of course, the cast article may be formed of a different metal if desired. The molten metal alloy may be solidified in a cavity  40  in the mold  34  with a crystallographic structure which is equiaxed, columnar grain, or single crystal. Although a mold  34  for casting a single article has been illustrated schematically in FIG. 1, it is contemplated that the mold  34  could be constructed so as to have two or more article mold cavities  40 . For example the mold  34  may have the construction illustrated in U.S. Pat. Nos. 3,714,977; 4,763,716; or 4,969,501. It is contemplated that the mold  34 , may have any one of many different known constructions and have any desired number of mold cavities. 
     The molten metal is poured into the mold  34  through a funnel  42 . Once the cavity  40  in the mold  34  has been filled with molten metal, the chill plate  36  is lowered to withdraw the mold from a cylindrical heating chamber  44  in the furnace assembly  22 . 
     During pouring of the molten metal into the mold  34  and withdrawal of the mold from the furnace assembly, the heating chamber  44  may be maintained at a temperature of approximately 3,000 degrees Fahrenheit. Of course, the temperature in the heating chamber  44  may be different for different metals. 
     As the mold  34  is withdrawn from the heating chamber  44 , the mold is exposed to a relatively cool environment disposed below the furnace assembly  22 . The molten metal in the mold cavity  40  solidifies upward from a lower end portion  48  of the mold  34  toward an upper end portion  50  of the mold. A solidification front between liquid and solid metal moves upward relative to the mold  34  as the mold is withdrawn from the heating chamber  44 . In order to promote upward solidification of molten metal in the mold cavity  40  a long a generally horizontal solidification front as the mold  34  is withdrawn from the heating chamber  40 , it is advantageous to maintain a relatively large temperature gradiant between the heating chamber  44  and the environment disposed immediately beneath the furnace assembly  22 . 
     When the mold  34  is constructed so as to have a plurality of mold cavities  40 , the solidification fronts in each of the mold cavities will be at the same level as the mold is withdrawn from the furnace assembly  22 . The solidification fronts in the plurality of mold cavities will move upward from lower end portions of the mold cavities toward the upper end portions of the mold cavities. 
     Regardless of how many mold cavities  40  are provided in the mold  34 , a baffle  52  is provided at the lower end portion  54  of the heating chamber  44 . The baffle  52  is effective to retard the transmission of heat between the heating, chamber  44  and the environment immediately beneath the furnace assembly  22 . The baffle  52  (FIG. 2) has an annular outer section  60  which is connected with the furnace assembly  22  and a circular inner section  62 . The inner section  62  has an opening  64  through which the mold  34  extends. It should be understood that the inner and outer sections of the baffle  52  could have a configuration other than circular. 
     The opening  64  advantageously has a configuration which corresponds to a cross sectional configuration of the lower end portion  48  of the mold  34 . By forming the opening  64  with a configuration corresponding to the cross sectional configuration of the lower end portion of the mold  34 , the amount of space between the inner section  62  of the baffle  52  and the exterior of the lower end portion  48  of the mold  34  is minimized. By minimizing the space between the exterior of the lower portion  48  of the mold  34  and the inner section  62  of the baffle  52 , the baffle is effective to block radiation of heat from the heating chamber  44  during withdrawal of the lower portion of the mold  34  from the heating chamber. 
     When the mold  34  is constructed so as to have a plurality of article mold sections, in the manner disclosed in U.S. Pat. Nos. 3,714,977; 4,763,716; and 4,969,501, a plurality of openings  64  may be provided in the inner section  62  of the baffle  52 . There may be a separate opening for each article mold section. Alternatively, a plurality of article mold sections could extend through a single opening  64  in the baffle  52 . 
     The upper end portion  50  (FIG. 1) of the mold  34  has a substantially larger cross sectional configuration than the lower end portion  48  of the mold. Although the lower end portion  48  of the mold  34  can readily move through the opening  64 , the upper end portion  50  of the mold is too large to move through the opening  64 . Therefore, as the chill plate  36  and mold  34  are lowered relative to the furnace assembly  22 , the upper end portion  50  of the mold moves into engagement with the inner section  62  of the baffle  52 . The force applied against the inner section  62  of the baffle  52  is effective to release a plurality of connectors  70  (FIG. 2) which interconnect the outer section  60  and inner section  62  of the baffle  52 . 
     Once the connectors  70  have been released, the inner section  62  of the baffle moves away from the outer section  60  of the baffle and increases the size of the opening in the baffle. The resulting, relatively large opening in the outer section  60  of the baffle can accommodate the upper end portion  50  of the mold  34 . Therefore, during withdrawal of the upper end portion  50  of the mold  34  from the heating chamber  44 , only the outer section  60  of the baffle  52  is effective to block the transmission of heat from the heating chamber  44 . The inner section  62  of the baffle falls downward away from the furnace assembly onto the chill plate  36  which, at this time, is disposed in a substantial distance below the furnace assembly. 
     One-Piece Baffle 
     In accordance with one of a plurality of features of the present invention, the baffle  52  may be formed as one-piece. Portions of the outer section  60 , inner section  62 , and connectors  70  of the baffle  52  are all at least partially formed from a single piece of material. 
     As the mold  34  is withdrawn from the heating chamber  44 , the upper end portion  50  of the mold applies force against the inner section  62  of the baffle  52 . This force is effective to release the connectors  70 . 
     The force applied against the inner section  62  of the baffle  52  is effective to break the connectors  70 . This may result in the connectors  70  being broken with a tearing action or a snapping action. Once the connectors  70  have been broken to separate the inner section  62  from the outer section  60  of the baffle  52 , the inner section of the baffle falls downward away from the outer section of the baffle. This results in the formation of a relatively large opening in the outer section  60  of the baffle. This opening will have a size and configuration corresponding to the size and configuration of the inner section  62  of the baffle  52 . 
     In the embodiment of the baffle  52  illustrated in FIG. 2, the inner section  62  of the baffle  52  has a circular configuration and the outer section  60  of the baffle has an annular configuration. Therefore, when the connectors  70  are broken to release the inner section  62  of the baffle  52 , a relatively large circular opening is provided in the baffle  52 . The diameter of this relatively large opening is greater than the maximum transverse dimension of the upper end portion  50  of the mold  34 . Therefore, the upper end portion  50  of the mold  34  can readily pass through the opening as the chill plate  36  continues to be lowered. 
     Although the periphery of the illustrated inner section  62  of the baffle  52  (FIG. 2) has been formed with a circular configuration, it is contemplated that the inner section  62  of the baffle could have a different peripheral configuration if desired. For example, the inner section  62  of the baffle  52  could have an outer edge with a configuration corresponding to the cross sectional configuration of the upper end portion  50  of the mold  34 . The outer edge of the inner section  62  of the baffle  52  would be larger in size than the cross sectional size of the upper end portion  50  of the mold  34  to enable the mold to move through an opening formed by separation of the inner section from the outer section  60  of the baffle. 
     When the inner section  62  of the baffle  52  is separated from the outer section  60  of the baffle by releasing the connectors  70 , the opening which is formed in the outer section  60  of the baffle will be larger than the cross sectional size of the upper end portion  50  of the mold  34 . Therefore, the upper end portion of the mold  34  can be readily moved through the opening which results from separation of the inner section  62  of the baffle  52  from the outer section  60  of the baffle as the chill plate  36  continues to be lowered. The opening which is formed in the outer section  60  of the baffle  52  may have any desired configuration. 
     As initially formed, the inner section  62  of the one-piece baffle  52  may be separated from the outer section  60  of the baffle by a plurality of slits  74  (FIGS.  2  and  3 ). The slits  74  extend between upper and lower major side surfaces  76  and  78  of the baffle  52  (FIG.  3 ). The upper major side surface  76  extends parallel to the lower major side surface  78  of the baffle. Although the slits  74  extend perpendicular to the side surfaces  76  and  78  of the baffle  52 , the slits may be skewed relative to the side surfaces of the baffle if desired. 
     Prior to releasing of the connectors  70  (FIGS.  2  and  4 ), the portion of the upper major side surface  76  of the baffle  52  disposed on the inner section  62  and connectors of the baffle is disposed in a coplanar relationship with the portion of the upper major side surface  76  disposed on the outer section  60  of the baffle. Similarly, the portion of the lower major side surface  78  disposed on the inner section  62  and connectors  70  of the baffle  52  is disposed in a coplanar relationship with the portion of the lower major side surface  78  disposed on the outer section  60  of the baffle. 
     The outer section  60 , inner section  62  and connectors  70  of the one-piece baffle  52  are all at least partially formed from the same piece of material. The single piece of material from which the outer section  60 , inner section  62 , and connectors  70  are all at least partially formed has a circular configuration with a diameter corresponding to the diameter of a circular opening at the lower end portion  54  of the heating chamber  44  (FIG. 1) The single piece of material from which the baffle  52  is formed extends from the outer section  60 , through the connectors  70 , to the inner section  62 . Of course, if the lower end portion of the heating chamber  44  had a different configuration, the single piece of material forming the baffle  52  would be cut to have a configuration which is different than the circular configuration illustrated in FIG.  2 . 
     The outer section  60 , inner section  62  and connectors  70  of the one-piece baffle  52  may all be formed from a single piece of material. Alternatively, the outer section  60 , inner section  62  and/or connectors  70  may be formed of a plurality of pieces which are interconnected to form a baffle  52  having a one-piece construction. However, one of the plurality of pieces of the baffle  52  would form at least a portion of the outer section  60 , inner section  62  and connectors  70 . 
     The illustrated baffle  52  (FIGS. 2 and 4) is entirely formed by a single piece of material which completely forms the outer section  60 , inner section  62  and connectors  70 . Thus, the specific baffle  52 , illustrated in FIGS. 2-4, consists of a single undivided piece of material. In the specific embodiment illustrated in FIG. 2, the single piece of material is a graphite felt. However, the material may be a ceramic or refractory metal if desired. Of course, the baffle  52  may be formed of other materials. 
     When the mold  34  is constructed so as to have two or more article mold cavities, in the manner previously mentioned, the inner section  62  of the baffle  52  may have a configuration which is different than the illustrated configuration. For example, the slits  74  may be arranged so as to partially define an opening through which the periphery of gating connected with a plurality of article molds can easily pass. This would enable the mold  34  to be constructed with a plurality of runners extending from a pour cup to each of a plurality of article mold cavities. 
     The baffle  52  may be provided with one or more radial slits to facilitate positioning the baffle relative to a relatively large base end portion of a mold, in a manner similar to that disclosed in U.S. Pat. No. 4,757,856. The slit or slits to facilitate positioning the baffle  52  relative to a relatively large base end portion of a mold would extend from a radially outer edge of the outer section  60  to the opening  64  in the inner section  62  of the baffle. The slit or slits to facilitate positioning of the baffle relative to a mold may extend through one or more of the connectors to or may be spaced from the connectors. The opening  64  may be configured to have two or more sections to receive end portions of two or more article mold sections of a mold. 
     In the embodiment of the baffle  52  illustrated in FIG. 2, the slits  74  forming the inner section  62  are disposed in a circular array having a center which is coincident with the center of a circular outer rim portion  82  of the outer section  60  of the baffle  52 . The connectors  70  are disposed between end portions of adjacent slits  74 . The connectors  70  are formed with the same thickness and construction as the outer section  60  and inner section  62  of the baffle  52  (FIG.  4 ). 
     Until the connectors  70  are broken to release the inner section  62  of the baffle for movement relative to the outer section  60  of the baffle, there is a continuous uninterrupted body of material extending through the connectors  70  between the outer and inner sections of the baffle. If desired, the connectors  70  may be weakened by indenting or cutting partway through the material of the baffle  52  at the connectors. Regardless of whether or not the connectors  70  are preweakened to facilitate breaking of the connectors, the connectors  70  are formed by material which is one-piece with material forming the outer section  60  and inner section  62  of the baffle  52 . 
     It is contemplated that the baffle  52  may be formed of many different materials. However, the baffle  52  is formed of a material which is capable of withstanding the relatively high temperatures to which it is exposed as a result of the high temperatures in the heating chambers  44 . The baffle  52  may be formed of graphite, a suitable ceramic, or a suitable refractory metal. It is believed that it may be desired to form the baffle  52  as one-piece composed of one or more layers of graphite felt and/or graphite foil. The graphite felt may be enclosed by layers of graphite foil. Although the baffle  52  would have a multi layered construction, one of the layers of the baffle would form at least a portion of the outer section  60 , inner section  62 , and connectors  70 . 
     In the embodiment of the invention illustrated schematically in FIG. 1, the outer rim portion  82  of the outer section  60  of the baffle  52  is clamped between a base member  86  which supports the furnace assembly  22  and the cylindrical radiation liner  28 . However, the baffle  52  may be mounted in the furnace assembly  22  in any one of many known ways. For example, one or more releasable connectors may be utilized to mount the baffle  52  in the furnace assembly  22 . 
     After the chill plate  36  has been moved to the raised position illustrated in FIG. 1, the cover  30  is removed from the furnace assembly  22  and the mold  34  is positioned in the heating chamber  44 . The lower end portion  48  of the mold extends through the opening  64  in the inner section  62  of the baffle  52  and engages the chill plate  36 . The cover  30  is then replaced. Alternatively, the baffle  52  and mold  34  may both be positioned on the chill plate  36  when the chill plate is in a fully lowered position. The baffle  52  may be positioned on the chill plate  36  with a central axis of the chill plate extending through the opening  64 . The mold  34  may be positioned on the chill plate  36  with a lower end portion  48  of the mold extending through the opening  64  and with the mold and chill plate in a coaxial relationship. 
     If the mold  34  has a relatively large base plate on flange at a lower end portion  48  of the mold, the baffle  52  may be provided with a slit which extends from the opening  64  in the inner section  62  to a radially outer edge of the rim portion  82  of the outer section  60  of the baffle. This slit allows the baffle  52  to be flexed and positioned around the lower end portion  48  of the mold  34  at a location above the base plate or flange. This would result in the baffle  52  overlying the base plate or flange at the lower end portion of the mold  32  in a manner similar to that disclosed in U.S. Pat. Nos. 3,714,977 and 4,969,501. 
     Once the baffle  52  has been positioned on the chill plate  36 , the chill plate is raised into the furnace assembly  22 . The baffle  52  is connected with the furnace assembly  22  by a suitable retainer. The retainer may have a construction similar to the construction disclosed in U.S. Pat. No. 4,774,992 or other known construction. Alternatively, latches similar to the latches illustrated in FIGS. 12-14 herein may be used to connect the baffle  52  with the furnace assembly  22 . 
     If desired, the baffle  52  may be divided into a plurality of segments in a manner similar to the disclosure in U.S. Pat. No. 4,969,501. If this is done, the segments of the baffle may be interconnected after they have been positioned relative to the mold  34 . Dividing the baffle  52  into segments would facilitate placement of the baffle relative to a complicated mold structure. However, dividing the baffle  52  into segments would complicate construction of the baffle, would increase the time required to position the baffle, and would weaken the baffle. Therefore, unless required by a complicated mold structure, it is believed that it will be preferred to avoid dividing baffle  52  into segments and reconnecting the segments. 
     After the mold  34  has been preheated to a desired temperature by operation of the furnace assembly  22 , molten metal is poured through the funnel  42  into the mold cavity  62 . After the mold cavity  40  has been filled with molten metal, the chill plate  36  is slowly lowered to withdraw the mold  34  from the heating chamber  44 . As this occurs, the molten metal solidifies with a solidification front which is disposed adjacent to the baffle  52 . Therefore, as the mold  34  is lowered, the solidification front moves upward in the mold cavity  40  toward the upper end portion  50  of the mold. As this occurs, the solidification front remains adjacent to the baffle  52 . 
     As the mold  34  continues to be lowered from the heating chamber  44 , the relatively large upper end portion  50  of the mold  34  moves into engagement with the portion of the upper major side surface  76  of the baffle  52  disposed adjacent to the opening  64  through the inner section  62  of the baffle. As the chill plate  36  continues to be lowered, force is applied against the upper side of the inner section  62  of the baffle  52  by the upper portion  50  of the mold. This force is transmitted to the connectors  70 . The force transmitted from the mold  34  to the connectors  70  is effective to release the connectors. 
     Depending upon the characteristics of the material from which the baffle  52  is formed, the connectors  70  may release with a tearing action or with a snapping action. Thus, if the baffle  52  is formed of a flexible graphite felt, the connectors  70  may be broken with a tearing action. Alternatively, if the one-piece baffle  52  is formed of a relatively brittle material, such as a ceramic or a refractory metal, the connectors  70  may be brittle and break with a snapping action. 
     The one-piece baffle  52  may be formed with a layered construction illustrated in FIG.  5 . If the baffle  52  is formed with a layered construction, the baffle may have a graphite felt inner layer  88 . A graphite foil upper layer  90  may be positioned on and connected to the inner layer  88 . Similarly, a graphite foil lower layer  92  may be positioned on and connected to the inner layer  88 . In the embodiment illustrated in FIG. 5, the upper and lower, layers  90  and  92  are cut at  94  and  96  to weaken the connectors  70  at locations disposed between the outer and inner sections of the one-piece baffle  52 . The inner layer  88  forms at least a portion of the outer section  60 , inner section  62 , and connectors  70 . In the embodiment illustrated in FIG. 5, the inner layer  88  is coextensive with the outer section  60 , inner section  62 , and connectors  70 . 
     Once the connectors  70  have been broken, the inner section  62  of the baffle  52  falls downward onto the chill plate  62 . As this occurs, a relatively large opening is formed in the outer section  60  of the baffle. The opening formed in the outer section  60  of the baffle  52  is large enough to enable the upper end portion  50  of the mold to freely move downward through the baffle as the chill plate  36  continues to be lowered. 
     In the embodiment of the invention illustrated in FIG. 2, a circular opening is formed in the center of the outer section  60  of the baffle  52  when the connectors  70  are broken to release the inner section  62 . However, it is contemplated that the slits  74  could have a configuration other than the arcuate configuration illustrated in FIG. 2 so that the opening formed in the outer section  60  of the baffle  52  would have a configuration which is different than a circular configuration. For example, the opening formed in the outer section  60  of the baffle may have a configuration similar to and slightly larger than the cross sectional configuration of the upper end portion  50  of the mold  34 . 
     Baffle With Separate Sections and Connectors 
     In the embodiments of the invention illustrated in FIGS. 1-5, the outer section  60 , inner section  62  and connectors  70  of the baffle  52  are all at least partially formed from one-piece of material, for example, the inner layer  88  of FIG.  5 . In the embodiment of the invention illustrated in FIGS. 6-8, the outer section, inner section, and connectors for the baffle are formed by separate pieces. Since the embodiment of the invention illustrated in FIG. 6 are generally similar to the embodiments of the invention illustrated in FIGS. 1-5, similar numerals have been utilized to designate similar components, the suffix letter “a” being added to the numerals of FIG. 6 to avoid confusion. 
     A baffle  52   a  is utilized in association with a furnace assembly  22  (FIG. 1) in the same manner as is the baffle  52 . The baffle  52   a  (FIG. 6) includes an annular outer section  60   a  and a circular inner section  62   a . The circular inner section  62   a  is separate from the annular outer section  60   a . An opening, corresponding to the opening  64  of FIG. 1, is provided in the inner section  60   a.    
     A circular slit  74   a  separates the outer section  60   a  from the inner section  62   a  The slit  74   a  forms a circular opening in the outer section  60   a . The inner section  62   a  is disposed in the opening in the outer section  60   a . If desired, the inner section  62   a  and the slit  74   a  may be formed with a configuration which is a different than a circular configuration. If this was done, the opening in the outer section  60   a  would have a non-circular configuration. 
     A plurality of connectors  70   a  extend between the outer section  60   a  and the inner section  62   a  and hold the outer and inner sections against movement relative to each other. An upper major side surface  76   a  of the outer section  60   a  is disposed in a coplanar relationship with an upper major side surface  92  on the inner section  62   a . Similarly, a lower major side surface  78   a  on the outer section  60   a  on the baffle  52   a  is disposed in a coplanar relationship with a lower major side surface  94  on the inner section  62   a.    
     The connector  70   a  interconnects the outer section  60   a  and inner section  62   a  to maintain the upper major side surfaces  76   a  and  92  of the baffle  52   a  in one plane which extends parallel to a plane in which the lower major side surfaces  78   a  and  94  of the baffle are disposed. The connector  70   a  is formed separately from the outer section  60   a  and inner section  62   a  of the baffle  52   a . The connector  70   a  is secured to and extends between the outer section  60   a  and inner section  62   a . The connector  70   a  is formed of a material which is different than the material which forms the outer section  60   a  and inner section  62   a . However, the outer section  60   a , inner section  62   a , and connector  70   a  may be formed of the same material. 
     The annular outer section  60   a  of the baffle  52   a  extends around the inner section  62   a  of the baffle. Thus, the circular inner section  62   a  is disposed in a circular opening formed in the outer section  60   a . The outer section  60   a  of the baffle  52   a  may be connected with the furnace assembly  22  in the same manner as illustrated in FIG. 1. A plurality of connectors  70   a  transmit force between the outer section  60   a  and inner section  62   a  of the baffle  52   a  to maintain the baffle in the opening in the outer section during withdrawal of the lower portion of the mold from the heating chamber of the furnace assembly. 
     In the embodiment illustrated in FIG. 6, the connector  70   a  is formed separately from the outer section  60   a  and inner section  62   a . The illustrated connect or  70   a  is a connector member or staple having a leg or end portion  102  which engages the outer section  60   a  of the baffle  52   a . The connector  70   a  has a leg or end portion  104  which engages the inner section  62   a  of the baffle  52   a . An intermediate portion  106  extends between the two end portions  102  and  104  and spans the slit  74   a.    
     In the embodiment of the connector  70   a  illustrated in FIG. 6, the two end portions  102  and  104  have longitudinal central axes which extend transverse to a longitudinal central axis of the intermediate portion  106 . Although the end portions  102  and  104  extend perpendicular to the intermediate portion  106  in the illustrated embodiment of the connector  70   a , it is contemplated that the end portions  102  and  104  could be skewed relative to the intermediate portion  106  and extend toward each other. This would result in the connectors  70   a  being effective to interconnect the outer section  60   a  and the inner section  62   a  of the baffle  52   a  with a clinching action. 
     The connector  70   a  may be formed of any desired material. For example, the connector  70   a  may be formed of a ceramic material. Alternatively, the connector  70   a  may be formed of a metal capable of withstanding the high temperatures to which it is exposed. Although the intermediate portion  106  of the connector  70   a  has been illustrated in FIG. 6 as extending along the upper major side surfaces  76   a  and  92  of the baffle  52   a , it is contemplated that the connector  70   a  could be disposed on the lower side of the baffle. 
     Positioning the connector  70   a  on the lower side of the baffle  52   a  would result in the connector being disposed adjacent to the chill plate  36  (FIG.  1 ). By positioning the connector adjacent to the chill plate  36 , the temperature to which the connector  70   a  is exposed tends to be minimized. If desired, the end portions  102  and  104  could be eliminated from the connector  70   a  and the connector located between the upper major side surfaces  76   a  and  92  and the lower major side surfaces  78   a  and  94  of the baffle  52   a . If this was done, it may be desired to increase the length of the intermediate portion  106  from the relatively short length illustrated in FIG.  6 . 
     Regardless of whether the connector  70   a  is disposed adjacent to the upper side of the baffle  52   a  (as illustrated in FIG.  6 ), adjacent to the lower side of the baffle, or disposed between upper and lower sides of the baffle, the connector spans the slit  74   a  which separates the outer section  60   a  from the inner section  62   a  of the baffle. By spanning the joint between the outer section  60   a  and inner section  62   a  of the baffle  52   a , the connector  70   a  is effective to transmit force from the outer section  60   a  of the baffle to the inner section  62   a  of the baffle to hold the inner section of the baffle in the opening in the outer section of the baffle during withdrawal of the lower portion of the mold  34  (FIG. 1) from the heating chamber  44 . 
     The outer section  60   a  consists of a single layer of graphite felt. Similarly, the inner section  62   a  consists of a single layer of graphite felt. However, the outer and inner sections  60   a  and  62   a  may have a different construction if desired. For example, the outer and inner sections  60   a  and  62   a  may have the multilayered construction previously described in conjunction with FIG.  5 . 
     When a metal article is to be cast in the mold  34 , the baffle  52   a  is mounted in the lower end portion of the heating chamber  44  in the manner previously described in connection with the embodiment of the invention illustrated in FIGS. 1-5. The chill plate  36  is moved upward to a position adjacent to the lower side of the baffle  52   a . The cover  30  (FIG. 1) is then removed and the mold  34  positioned on the chill plate. Of course, the mold  34  may be positioned on the chill plate  36  and raised toward the furnace assembly with the chill plate. 
     Once molten metal has been poured into the mold  34 , the chill plate  36  is slowly lowered. Lowering the chill plate  36  results in the mold  34  being slowly withdrawn from the heating chamber  44 . As the mold  34  is withdrawn from the heating chamber  44 , the molten metal in the mold solidifies at a solidification front which is maintained adjacent to the baffle  52 . This results in the solidification front being displaced upward in the mold cavity  40  as the mold is withdrawn from the heating chamber  44 . 
     Upon completion of withdrawal of the lower portion  48  of the mold  34  from the heating chamber  44 , the upper end portion  50  of the mold moves into engagement with the upper major side surface  92  (FIG. 6) of the inner section  62   a  of the baffle  52   a . The force applied against the upper major side surface  92  of the inner section  62   a  of the baffle  52   a  is effective to release the connectors  70   a . The inner section  62   a  of the baffle  52   a  then drops downward onto the chill plate  36 . This results in the formation of a relatively large opening in the stationary outer section  60   a  of the baffle  52   a . As the chill plate  36  continues to be lowered, the upper end portion  50  of the mold  34  moves through the relatively large opening created by separating the inner section  62   a  of the baffle  52   a  from the outer section  60   a  of the baffle. 
     As the upper end portion  50  of the mold  34  moves into initial engagement with the inner section  62   a  of the baffle  52   a , the mold applies a downward force against the upper major side surface  92  of the inner section  62   a . This force is effective to move the inner section  62   a  downward relative to the stationary outer section  60   a  of the baffle  52   a . As this occurs, the inner section  62   a  of the baffle slides along the end portion  104  of the connector  70   a . As the inner section  62   a  continues to move downward and out of the circular opening formed in the outer section  60   a  of the baffle  52   a , the end portion  104  of the connector  70   a  and the inner section  62   a  of the baffle are separated to release the baffle for downward movement onto the chill plate under the influence of gravity. 
     Although the specific connector  70   a , illustrated in FIG. 6, is released by being disengaged from the inner section  62   a , the connector could be released in a different manner if desired. For example, the connector  70   a  could be deformed and/or torn from the outer section  60   a  or inner section  62   a . The connector  70   a  may be constructed so as to break at the intermediate portion  106  of the connector to release the inner section  62   a  of the baffle  52   a.    
     Although only a single connector  70   a  has been illustrated schematically in FIG. 6, it should be understood that there are a plurality of identical connectors  70   a . The plurality of connectors  70   a  span the slit  74   a  tat spaced apart locations along the slit. The number of connector members  70   a  utilized to interconnect the outer section  60   a  and inner section  62   a  of the baffle  52   a  will be a function of the weight of the inner section  62   a  of the baffle. Thus, the greater the weight of the inner section  62   a  of a baffle, the greater the number of connectors  70   a  which will be utilized. For example, four connectors  70   a  may be positioned at spaced apart locations between the outer section  60   a  and inner section  62   a  of the baffle  52   a  in much the same manner as in which four connectors  70  are positioned in FIG.  2 . However, a greater or lesser number of connectors  70   a  may be utilized if desired. 
     In the embodiment of the invention illustrated in FIG. 6, a connector member extends along outer surfaces of the baffle  52   a . Thus, the connector member  70   a  extends along the upper major side surfaces  76   a  and  92  of the baffle. However, the connector member  70   a  may extend along the lower major side surfaces  78   a  and  94  of the baffle. 
     In the embodiment of the invention illustrated in FIG. 7, a connector is positioned in a joint between outer and inner sections of the baffle. Since the embodiment of the invention illustrated in FIG. 7 is generally similar to the embodiments of the invention illustrated in FIGS. 1-6, similar numerals will be utilized to identify to similar components, the suffix letter “b” being associated with the numerals of FIG. 7 to avoid confusion. 
     A baffle  52   b  has an outer section  60   b  which is connected with an inner section  62   b  by a connector  70   b . In the embodiment of the invention illustrated in FIG. 7, the connector  70   b  is located in a circular slit  74   b  between the annular outer section  60   b  and circular inner section  62   b  of the baffle. The connector  70   b  is disposed in the slit  74   b  between a plane containing an upper major side surface  76   b  of the outer section  60   b  and an upper major side surface  92   b  of the inner section  62   b  of the baffle and a plane containing a lower major side surface  78   b  on the outer section  60   b  and a lower major side surface  94   b  on the inner section  62   b  of the baffle  52   b . Although the connector  70   b  is disposed entirely within the slit  74   b , it is contemplated that a portion of the connector  70   b  could extend upward and/or downward from the slit. 
     The connector  70   b  transmits force between the outer section  60   b  and inner section  62   b  of the baffle  52   b  to support the inner section  62   b  of the baffle. The circular inner section  62   b  of the baffle is disposed in a circular opening formed in the annular outer section  60   b  of the baffle. The upper major side surfaces  76   b  and  92   b  of the baffle are disposed in a coplanar relationship., Similarly, the lower major side surfaces  78   b  and  94   b  of the baffle are disposed in a coplanar relationship. An opening, corresponding to the opening  64  of FIG. 2, is provided in the inner section  62   b  of the baffle  52 . 
     The connector  70   b  is formed by one or more bodies of adhesive. The adhesive of the connector  70   b  is connected to an annular inner rim portion  110  of the outer section  60   b  of the baffle  52   b . The adhesive of the connector  70   b  is also connected to an annular outer rim portion  112  of the inner section  62   b  of the baffle  52   b . This enables force to be transmitted through the adhesive forming the connector  70   b  to hold the inner section  62   b  of the baffle in an opening formed in the outer section  60   b  of the baffle  52   b.    
     The connector  70   b  may be formed by a plurality of relatively small bodies or dots of adhesive which are disposed in the slit  74   b  between the outer section  60   b  and inner section  62   b  of the baffle  52   b . Alternatively, the connector  70   b  may be formed by an annular ring of adhesive which is coextensive with the slit  74   b . Of course, a plurality of spaced apart elongated bodies of adhesive may be provided rather than small dots or a single body of adhesive. 
     The outer section  60   b  consists of a single layer of graphite felt. Similarly, the inner section  62   b  consists of a single layer of graphite felt. However, the outer and inner sections  60   b  and  62   b  may have different construction if desired. For example, the outer and inner sections  60   b  and  62   b  may have the multilayered construction previously described in conjunction with FIG.  5 . 
     When the baffle  52   b  is mounted on the lower end portion of the furnace assembly  22 , in the same manner as is illustrated schematically for the baffle  52  in FIG. 11, force is transmitted through the adhesive of the connector  70   b  to hold the inner section  62   b  in the circular opening formed in the outer section  60   b  of the baffle. As the mold  34  is withdrawn from the heating chamber  44  (FIG.  1 ), the upper end portion  50  of the mold moves into engagement with inner section  62   b  of the baffle  52   b  and applies force against the inner section of the baffle. 
     The force applied by the upper end portion  50  of the mold  34  against the inner section  62   b  of the baffle  52   b  is effective to release the connector  70   b . This may be done tearing the material of the baffle  52   b  adjacent to the adhesive forming the connector  70   b  or by breaking the adhesive material itself. Once the connector  70   b  has been released, the inner section  62   b  of the baffle  52   b  is free to fall downward onto the chill plate  36 . The upper end portion  50  of the mold  34  can then be moved through the relatively large opening formed by disconnecting the inner section  62   b  of the baffle from the outer section  60   b  of the baffle. 
     In the embodiment of the invention illustrated in FIG. 6, the connector  70   a  is formed by a member which extends between the outer and inner sections  60   a  and  62   a  of the baffle  52   a . In the embodiment of the invention illustrated in FIG. 7, the connector is formed by adhesive which extends between the outer section  60   b  and inner section  62   b  of the baffle  52   b . In the embodiment of the invention illustrated in FIG. 8, the connector is formed by both a member and a body of adhesive which extend between the outer section and the inner section of the baffle. Since the embodiment of the invention listed in FIG. 8 is generally similar to the embodiments of the invention illustrated in FIGS. 1-7, similar numerals will be utilized to designate similar components, the suffix letter “c” being associated with the numerals of FIG. 8 to avoid confusion. 
     A baffle  52   c  (FIG. 8) includes an annular outer section  60   c  and a circular inner section  62   c . An opening corresponding to the opening  64  of FIG. 1, is formed in the inner section  62   c  (FIG.  8 ). The outer and inner sections  60   c  and  62   c  are separated by circular slit  74   c.    
     A connector  70   c  spans to slit  74   c . The connector  70   c  is effective to hold the inner section  62   c  in a circular opening formed in the outer section  60   c  of the baffle. An upper major side surface  76   c  on the outer section  60   c  of the baffle  52   c  is disposed in a coplanar relationship with an upper major surface  92   c  on the inner section  62   c  of the baffle. Similarly, a lower major side surface  78   c  on the outer section  60   c  of the baffle  52   c  is disposed n a coplanar relationship with a lower major side surface  94   c  on the inner section  62   c  of the baffle. 
     The connector  70   c  is formed by a connector member  120  which spans the slit  74   c  and a body  122  of adhesive. The body  122  of adhesive connects the connector member  120  to the outer section  60   c  and inner section  62   c  of the baffle  52   c.    
     The connector member  120  may be flexible and formed of a material which can withstand relatively high temperatures, such as a graphite cloth. The connector member  120  may be tape. Alternatively, the connector member  120  may be formed of a rigid material, such as a ceramic or refractory material. Regardless of whether the connector member  120  is flexible or rigid, it is connected with both the outer section  60   c  and the inner section  62   c  of the baffle  52   c  by the body  122  of adhesive. 
     The body  122  of adhesive may have a configuration corresponding to a configuration of the connector member  120 . Thus, the connector member  120  may be formed by an elongated strip or rod and the body  122  may be an elongated strip of adhesive. Although only one connector member  120  and body  122  of adhesive are illustrated in FIG. 8, it should be understood that there are a plurality of connector members and bodies of adhesive arranged in a circular array along the slit  74   c.    
     Alternatively, the connector member  120  may have an annular configuration and be coextensive the slit  74   c . If this is done, the body  122  of adhesive would have an annular configuration and be coextensive with the slit  74   c.    
     The connector member  120  and body  122  of adhesive are illustrated in FIG. 8 as being disposed adjacent to the upper side surfaces  76   c  and  92   c  of the outer and inner sections  60   c  and  62   c  of the baffle  52   c . However, the connector member  120  and body  122  of adhesive may be disposed adjacent to the lower side surfaces  78   c  and  94   c  of the outer and inner sections  60   c  and  62   c  of the baffle  52   c . This would result in the connector  70   c  being exposed to the relatively cool chill plate  36 . 
     The outer section  60   c  consists of a single layer of graphite felt. Similarly, the inner section  62   c  consists of a single layer of graphite felt. However, the outer and inner sections  60   c  and  62   c  may have a different construction if desired. For example, the outer and inner sections  60   c  and  62   c  may have the multilayered construction previously described in conjunction with FIG.  5 . 
     Connector Rods 
     In the embodiments of the invention illustrated in FIGS. 6-8, the connectors  70   a ,  70   b , and  70   c  extend between the outer sections and inner sections of the baffles. In the embodiment of the invention illustrated in FIG. 9, the connectors extend from one portion of the outer section of the baffle, along the inner section of the baffle, to another portion of the outer section of the baffle. Since the embodiment of the invention illustrated in FIG. 9 is generally similar to the embodiments of the invention illustrated in FIGS. 1-8, similar numerals will be utilized to designate similar components, the suffix letter “d” being associated with the numerals of FIG. 9 to avoid confusion. 
     A baffle  52   d  has an annular outer section  60   d  and a circular inner section  62   d . The outer section  60   d  and inner section  62   d  are separated by a circular slit  74   d . A connector  70   d  supports the circular inner section  62   d  in a circular opening  130  formed in the annular outer section  60   d.    
     When the inner section  62   d  is disposed in the opening  130  in the outer section  60   d , an upper side surface of the outer section  60   d  is disposed in a coplanar relationship with an upper side surface of the inner section  62   d . Similarly, a lower side surface of the outer section  60   d  is disposed in a coplanar relationship with an outer side surface of an inner section  62   d  in the manner previously explained in conjunction with the embodiments of the invention illustrated in FIGS. 6-8. In the embodiments of the invention illustrated in FIGS. 6-9 both upper side surfaces of the inner and outer sections of the baffle and lower side surfaces of the inner and outer sections of the baffle are disposed in a coplanar relationship. However, it is contemplated that only the upper side surfaces of the inner and outer sections of the baffle may be disposed in a coplanar relationship. Alternatively, only the lower side surfaces of the inner and outer sections of the baffle may be disposed in a coplanar relationship. 
     The connector  70   d  includes a plurality of elongated members or rods  134  and  136 . The rods  134  and  136  extend in a chordal manner across the circular opening  130  in the outer section  60   d  and are spaced from an opening  64   d  in the inner section  62   d . Thus, the left (as viewed in FIG. 9) end portion  140  of the connector member or rod  134  is disposed in engagement with one portion of the outer section  60   d . A right (as viewed in FIG. 9) end portion  142  of the connector member  134  is disposed in engagement with another portion of the outer section  60   d . An intermediate portion  144  of the connector member or rod  134  is disposed in engagement with the inner section  62   d  and forms a chord to the circular opening  130 . The intermediate portion  144  of the connector member or rod  134  is spaced from the opening  64   d  in the inner section  62   d.    
     Similarly, the connector member or rod  136  includes a left (as viewed in FIG. 9) end portion  148  which is disposed in engagement with a portion of the outer section  60   d  of the baffle  52   d . A right (as viewed in FIG. 9) end portion  150  of the connector member or rod  136  is disposed in engagement with another portion of the outer section  60   d . An intermediate portion  152  of the rod extends across the opening  130  in the outer section  60   d  in a chordal manner. The connector member or rod  136  is spaced from the opening  64   d . Since the connector members or rods  134  and  136  are spaced from the opening  64   d  in the inner section  62   d , the mold  34   d  can be positioned in the opening  64   d  without interference with the connector members or rods. 
     In the embodiment of the invention illustrated in FIG. 9, the connector members or rods  134  and  136  are disposed in engagement with lower side surfaces of the outer section  60   d  and inner section  62   d . The connector members or rods  134  and  136  support the outer section  60   d  and inner section  62   d  with their lower side surfaces in a coplanar relationship. The outer section  60   d  and inner section  62   d  have the same thickness. Therefore, the upper side surfaces of the outer section  60   d  and inner section  62   d  are disposed in a coplanar relationship. The connector members or rods  134  and  136  have longitudinal central axes which extend parallel to the upper and lower major side surfaces of the outer section  60   d  and inner section  62   d  of the baffle  52   d.    
     The left and right end portions  140  and  142  of the connector member or rod  134  rest on the base member  86  (FIG. 1) at a location beneath the outer section  60   d . Similarly, the left and right end portions  148  and  150  of the connector member or rod  136  rest on the base member  86  at locations beneath the outer section  60   d . The connector members or rods  134  and  136  span the circular opening  130 . This enables the connector members or rods  134  and  136  to support the inner section  62   d  of the baffle  52   d  in the circular opening  130 . 
     The end portions  140 ,  142 ,  148  and  150  of the connector members or rods  134  and  136  rest on a flat upper surface of the base member  86  (FIG.  1 ). However, it is contemplated that it may be desired to provide notches in the base member  86  to locate the connector members or rods  134  and  136  relative to the base member. 
     When the baffle  52   d  is to be installed in the furnace assembly  22  (FIG. 1) the connector members or rods  134  and  136  are positioned on the base member  86 . To facilitate positioning of the connector members or rods  134  and  136 , the base member  86  may include a removable ring on which the rods rest. Alternatively, the cover  30  and radiation liner  28   b  may be removed from the furnace assembly  22  and the connector members or rods  134  and  136  positioned on the base  86 . 
     Once the connector members or rods  134  and  136  have been positioned on the base member  86 , the outer section  60   d  of the baffle  52   d  is positioned on the connector members or rods  134  and  136 . The inner section  62   d  is then positioned on the intermediate portions  144  and  152  of the connector members or rods  134  and  136 . This enables the connector members or rods  134  and  136  to support the inner section  62   d  in the circular opening  130 . The radiation liner  28  may then be replaced in the furnace assembly  22 . Once the mold  34  has been positioned on the chill plate  36  with the lower end portion  48  of the mold extending through the opening  64   d  in the baffle  52   d , the cover  30  can be placed on the furnace assembly  22 . 
     After the heating chamber  44  and mold  34  have been heated to a desired temperature, molten metal is poured through the funnel  32  into the mold  34 . The chill plate  36  is then lowered to initiate withdrawal of the mold  34  from the furnace assembly  22 . 
     As the chill plate  36  is lowered and the mold  34  is withdrawn from the furnace assembly  22 , the upper end portion  50  of the mold moves into engagement with the inner section  62   d  adjacent to the periphery of the opening  64   d  and the connector members or rods  134  and  136 . The force applied against the inner section  62   d  of the baffle  52   d  by the upper end portion  50  of the mold  34  is effective to break the connector members or rods  134  and  136  with a snapping action. Breaking the connector members or rods  134  and  136  releases the inner section  62   d  for movement out of the circular opening  130  in the outer section  60   d . As this occurs, the inner section  62   d  of the baffle  52  falls downward onto the chill plate. The upper end portion  50  of the mold  34  can then move through the relatively large circular opening  130  in the stationary outer section  60   d  as the mold  34  continues to withdrawn from the furnace assembly. 
     The connector members or rods  134  and  136  are formed of a ceramic material such as quartz. However, the connector members or rods  134  and  136  could be formed of a different material if desired. 
     In the embodiment of the invention illustrated in FIG. 9, the connector members or rods  134  and  136  are separate from the outer section  60   d  and inner section  62   d  of the baffle  52   d . However, if desired, the connector members or rods  134  and  136  could be connected with the lower side of the baffle  52   d . The connector members or rods  134  and  136  may be connected with the lower side of the baffle  52   d  by a suitable adhesive or by mechanical fasteners. 
     Although the connector members or rods  134  and  136  are disposed beneath the baffle, the connector members or rods could be disposed above the baffle. If this was done, the connector members or rods  134  and  136  would be connected with the upper side of the inner section  62   d  of the baffle  52   d  by a suitable adhesive or mechanical fasteners. 
     If desired, the connector members or rods  134  and  136  may be embedded in the material forming the outer section  60   d  and inner section  62   d  of the baffle  52   d . This would result in the connector members or rods  134  and  136  being enclosed by the material of the baffle. 
     Rather than having the connector members or rods  134  and  136  extend between spaced apart locations on the outer section  60   d  of the baffle  52   d , the connector members or rods  134  and  136  could be shorter and extend only from the outer section  60   d  to the inner section  62   d  of the baffle  52   d . Thus, a circular array of three or more relatively short connector members or rods may extend radially inward from the outer section  60   d  to the inner section  52   d  without spanning the opening  130 . If this was done, the relatively short connector members or rods may be attached to the lower sides of the outer section  60   d  and inner section  62   d . Alternatively, the relatively short connector members or rods may be embedded in the material of the outer section  60   d  and inner section  62   d.    
     The outer section  60   d  of the baffle  52   d  consists of a single layer of graphite felt. Similarly, the inner section  62   d  consists of a single layer of graphite felt. However, the outer and inner sections  60   d  and  62   d  of the baffle  52   d  may have a different construction. For example, the outer and inner sections  60   d  and  62   d  may have the multilayered construction previously described in conjunction with FIG.  5 . 
     Baffle With Raised Inner Section 
     In the embodiments of the invention illustrated in FIGS. 1-9, the baffles  52  have been constructed with upper and lower major side surfaces of the outer sections  60  and inner sections  62  in a coplanar relationship. In the embodiment of the invention illustrated in FIGS. 10 and 11, the inner section of the baffle is disposed above and is supported by the outer section of the baffle. Since the embodiment of the invention illustrated in FIGS. 10 and 11 is generally similar to the embodiments of the invention illustrated in FIGS. 1-9, similar numerals will be utilized to designate similar components, the suffix letter “e” being associated with the numerals of FIGS. 10 and 11 to avoid confusion. 
     A baffle  52   e  is illustrated in FIG. 10 in a furnace assembly  22   e . The furnace assembly  22   e  has the same construction as the furnace assembly  22  of FIG. 1. A mold  34   e  extends through an opening  64   e  in a circular inner section  62   e  of the baffle  52   e . The mold  34   e  is supported on a circular chill plate  36   e.    
     In accordance with one of the features of the embodiment of the invention illustrated in FIGS. 10 and 11, the inner section  62   e  of the baffle  52   e  is disposed above and is supported by an annular outer section  60   e  of the baffle  52   e . When the mold  34   e  is to be withdrawn from the heating chamber  44   e  in the furnace assembly  22   e  in the manner previously explained in conjunction with the embodiment of the invention illustrated in FIG. 1, an upper end portion of the mold moves downward into engagement with the inner section  62   e  of the baffle  52   e . Force applied against the inner section  62   e  of the baffle  52   e  by the upper end portion of the mold is effective to deflect an annular inner rim  160  (FIG. 11) of the outer section  60   e . As this occurs, the baffle  52   e  moves into and through a circular opening  130   e  formed in the outer section  60   e  of the baffle  52   e.    
     The inner section  62   e  of the baffle  52   e  is then free to fall downward onto the chill plate  36   e . The relatively large upper end portion of the mold  34   e  may then move through the relatively large circular opening  130   e  formed in the outer section  60   e.    
     The circular inner section  62   e  may be placed on the upper major side surface of the outer section  60   e  without being connected to the outer section  60   e . This would enable the lower major side surface of the inner section  62   e  to slide on the upper major side surface of the outer section  60   e.    
     Alternatively, the inner section  62   e  of the baffle  52   e  may be secured to the outer section  60   e  of the baffle. This may be done with adhesive or with mechanical fasteners. Assuming that adhesive is utilized to connect the inner section  62   e  of the baffle  52   e  with the upper side of the outer section  60   e , spaced apart bodies of adhesive may be placed on either the annular inner rim portion  160  (FIG. 11) of the outer section  60   e  on an annular rim portion  164  of the inner section  62   d . Rather than using spaced apart bodies of adhesive, a single annular body of adhesive may be positioned on either the rim portion  160  of the outer section  60   e  or the rim portion  164  of the inner section  62   e  of the baffle  52   e.    
     It is contemplated that it may be desired to install the baffle  52   e  in the furnace  22   e  by first positioning the outer section  60   e  of the baffle in the furnace assembly and then moving the inner section  62   e  through the opening  130   e  in the outer section  60   e  of the baffle. If this is to be done, notches or slots may be formed in the rim portion  160  of the outer-section  60   e  of the baffle  52   e . The inner section  62   e  of the baffle would then be oriented with its major side surfaces extending perpendicular to the major side surfaces of the outer section  60   e  of the baffle and aligned with the notches in the rim portion  160  of the outer section  60   e  of the baffle. This would allow the inner section  62   e  of the baffle to be moved upward through the opening  130  and then moved to the orientation illustrated in FIGS. 10 and 11. 
     The outer section  60   e  and inner section  62   e  of the baffle  52   e  may be cut from a single piece of material. If this is done, the cut may be formed as a portion of a cone having a central axis coincident with the centers of the outer section  60   e  and inner section  62   e  of the baffle  52   e . This results in the opening  130   e  in the outer section  60   e  of the baffle  52   e  having an axially downward and radially outward (as viewed in FIG. 11) sloping side surface. The rim portion  164  of the inner section  62   e  of the baffle  52   e  would have a radially inward and upward (as viewed in FIG. 11) slopping side surface which corresponds to the sloping side surface of the opening  130   e.    
     Although the outer section  60   e  and inner section  62   e  may be formed of many different materials, they are formed of graphite felt. If desired, the outer section  60   e  and inner section  62   e  of the baffle  52   e  may have a layered construction, similar to the layered construction of FIG.  5 . 
     In the embodiment illustrated in FIGS. 10 and 11, the inner section  62   e  of the baffle  52   e  is disposed above the outer section  60   e  of the baffle. However, if desired, the inner section  62   e  may be supported in the opening  130   e  in the outer section  60   e  baffle  52   e . To support the inner section  62   e  of the baffle  52   e  in the opening  130   e , the circular inner section  62   e  may be provided with radially outward projecting tabs which extend over and engage radially inward projecting tabs on the outer section  60   e.    
     Latches 
     In the embodiment of the invention illustrated in FIGS. 1-11, the baffle  52  is supported by a base portion  86  (FIG. 1) of the furnace assembly  22 . In the embodiments of the invention of the illustrated in FIGS. 12-14, the baffle is supported by latches connected with the furnace assembly. Since the embodiments of the invention illustrated in FIGS. 12-14 are generally similar to the embodiments of the invention illustrated in FIGS. 1-11, similar numerals will be utilized to designate similar components, the suffix letter “f” being associated with the embodiments of FIGS. 12 and 13. 
     A baffle  52   f  is disposed at a lower end portion of a furnace assembly  22   f . A mold  34   f  has a lower end portion  48   f  which extends through an opening  64   f  formed in the baffle  52   f  into engagement with a circular chill plate  36   f . The furnace assembly  22   f  has the same general construction as the furnace  22  of FIG.  1 . The baffle  52   f  may have the same construction as any one of the baffles illustrated in FIGS. 1-11. 
     In accordance with one of the features of the embodiment of the invention illustrated in FIGS. 12 and 13, a plurality of latches  170  are arranged in a circular array at the lower end portion of the furnace assembly  22   f . Although only two latches have been illustrated schematically in FIG. 12, it should be understood that additional latches may be provided if desired. In order to provide a stable support for the baffle  52   f , it is believed that it may be desired to have three or more latches disposed adjacent to the lower end portion of the furnace assembly  22   f.    
     When the mold  34   f  is to be positioned in the furnace assembly, the chill plate  36   f  may be lowered. The baffle  52   f  is then be placed on the upper side surface of the chill plate. The mold  34   f  may be positioned on the chill plate  36   f  with the lower end portion  48   f  of the mold extending through the opening  164   f  in the baffle  52   f.    
     Once the baffle  52   f  and mold  34   f  have been positioned on the chill plate  36   f , the chill plate is raised to move the mold into the heating chamber  44   f  of the furnace assembly  22   f . As the chill plate  34   f  is raised, a circular outer rim portion  82   f  of the baffle  52   f  engages the latches  170 . Upward force applied by the rim portion  82   f  of the baffle  52   f  is effective to operate the latches  170  to a retracted condition so that the baffle  52   f  can be moved upward past the latches  170 . Once the outer rim portion  82   f  of the baffle  52   f  has moved upward past the latches  170 , the latches operate to the illustrated extended condition. When the latches  170  are in a extended condition, they extend beneath the outer rim portion  82   f  of the baffle  52   f  to enable the latches to support the baffle. 
     When the mold  34   f  is to be withdrawn from the heating chamber  44   f , the chill plate  36   f  is lowered in the manner previously explained. As the mold moves downward, force applied against the baffle  52   f  by relatively large upper end portion of the mold releases connectors which interconnect outer and inner sections  60  and  62  of the baffle in the manner previously explained in conjunction with the embodiments of the invention illustrated in FIGS. 1-11. This enables the inner section of the baffle  52   f  to fall downward onto the chill plate  36   f . The upper portion of the mold  34   f  can then move through the resulting relatively large opening in the baffle  52   f.    
     The latches  170  may be manually actuated to a retracted condition to release the outer section of the baffle  52   f  after the mold has been withdrawn from the furnace assembly  22   f . The latches  170  may be manually actuated to the retracted condition by pulling on rods connected with the latches. Alternatively, the latches  170  may be actuated to the retracted condition by operating hydraulic or pneumatic motors connected with the latches. 
     It is contemplated that the latches  170  may have many different constructions. This specific latches  170  illustrated schematically in FIG. 12 have the construction illustrated in FIG.  13 . The latch  170  includes a latch member  172  which is biased toward the extended condition illustrated in FIG. 13 by a spring  174 . The latch member  172  is enclosed within a housing  176 . Suitable stops extend from the housing  176  into engagement with latch member  172  to limit movement of the latch member. Alternatively, the latch member  172  may be provided with a projection which engages a slot in the housing  176  to limit movement of the latch member  172  under the influence of the spring  174 . 
     When the baffle  52   f  and chill plate  36   f  are raised to move the mold  34   f  into the furnace assembly  22   f  in the manner previously described, the annular outer rim portion  82   f  of the baffle  52   f  moves into engagement with a cam surface  180  on the latch member  172 . Force applied against the cam surface  180  by the annular outer rim portion  82   f  of the baffle  52   f  forces the latch member into the housing  176  against the influence of the spring  174 . As the chill plate  36   f  and baffle  52   f  continue to be raised, the baffle moves above the latch member  172 . As this occurs, the spring  174  moves the latch member from a retracted condition to the extended condition illustrated in FIG.  13 . 
     When the chill plate  36   f  begins to move downward to withdraw the mold  34   f  from the heating chamber  44   f , the baffle  52   f  is held against movement relative to the furnace assembly  22   f  by engagement of a lower side of the baffle with a support surface  184  on the latch member  172 . This results in the baffle  52   f  being supported by the latches  170  during withdrawal of the lower portion  48   f  of the mold  34   f  from the heating chamber  44   f.    
     When the upper end portion  50   f  of the mold  34   f  engages the baffle  52   f , force is transmitted from the upper end portion of the mold  34   f  through the inner section and outer section of the baffle  52   f  to the latches  170 . This enables the upper end portion of the mold to apply force against the baffle  52   f  to release the connectors in the manner previously explained herein. Releasing the connectors allows the inner section of the baffle to fall downward onto the chill plate  36   f . The outer section of the baffle  52   f  is held in a position adjacent to the lower end portion of the heating chamber  44   f  by the latches  170 . 
     In the embodiment of the invention illustrated in FIGS. 12 and 13, the latches  170  have spring biased latch members  172 . In the embodiment of the invention illustrated in FIG. 14, the latches are gravity biased. Since the embodiment of the invention illustrated in FIG. 14 is generally similar to the embodiment of the invention illustrated in FIGS. 12 and 13, similar numerals will be utilized to identify similar components, the suffix “g” being associated with the numerals of FIG.  14 . 
     A plurality of latches  170   g  are mounted adjacent to the lower end portion of the furnace assembly  22   f  in the manner illustrated schematically for the latches  170  in FIG.  12 . The latch  170   g  includes a latch member  172   g  which is pivotally supported at  190  for movement between an extended condition illustrated in solid lines in FIG. 14 and a retracted condition in dashed lines in FIG.  14 . When the latch member  172   g  is in the extended condition illustrated in solid lines in FIG. 14, a relatively heavy nose end portion  194  of the latch member  172   g  is urged downward by the effect of gravity to position a stop surface area  196  on the latch member  172   g  in engagement with a stopped member  198 . 
     When a mold, corresponding to the mold  34   f  of FIG. 12 is to be moved into a furnace assembly corresponding to the furnace assembly  22   f , a baffle having any one of the constructions illustrated in FIGS. 1-11 is positioned on a chill plate. The baffle and mold are then raised to move the mold into a heating chamber of the furnace assembly in the manner previously explained in conjunction with the embodiment of the invention illustrated in FIG.  12 . 
     As the chill  36   f  plate and baffle  52   f  (FIG. 12) move upward toward the heating chamber of the furnace assembly, an annular outer rim portion  82   f  (FIG. 12) of the baffle moves into engagement with a cam surface  180   g  (FIG. 14) on the nose end portion  194  of the latch member  172   g . The force applied against the cam surface  180   g  (FIG. 14) pivots the latch member  172   g  in a counter clockwise direction (as viewed in FIG. 14) about the pivot connection  190 . A stop member  200  is provided to limit pivotal movement of the latch member  172   g  about the pivot connection  190 . 
     As the chill plate  36   f  (FIG. 12) and baffle  52   f  continue to move upward, the circular outer rim portion  82   f  of the baffle moves above the nose end portion  194  (FIG. 14) of the latch member  172   g . This releases the latch member  172   g  for clockwise pivotal movement from the orientation illustrated in dash lines in FIG. 14 to the orientation illustrated in solid lines in FIG.  14 . As this occurs, a support surface  184   g  moves beneath the lower surface of the baffle. 
     When the chill plate  36   f  (FIG. 12) is subsequently lowered to withdraw the mold  34   f  from the furnace assembly  22 , the baffle  52   f  moves downward onto the support surface  184   g  (FIG. 14) on the latch member  172   g . The support surface  184   g  is skewed at an acute angle to the path of movement of the chill, plate  36   f  (FIG.  12 ). Therefore, the support surface  184   g  tends to center the baffle  52   f  relative to the path of movement of the chill plate  36   f . As the chill plate  36   f  continues to be lowered, the upper end portion of the mold  34   f  engages the inner section of the baffle  52   f  and releases the connectors. As this is done, the outer section of the baffle is held stationary relative to the furnace assembly  22   f  by engagement with the support surfaces  184   g  on the latch members  172   g.    
     Conclusion 
     In view of the foregoing description, it is apparent that the present invention provides a new and improved apparatus and method for use in casting a metal article. The apparatus may include a furnace assembly  22  having a heating chamber  44 . A chill plate  36  may be provided to move a mold  34  into and out of the heating chamber  44 . A baffle  52  may be utilized at a lower end portion of the heating chamber  44  to at least partially block heat flow from the heating chamber during withdrawal of the mold  34  from the heating chamber. 
     The baffle  52  may have an inner section  62  with an opening  64  through which the mold  34  extends when the mold is in the heating chamber  44 . An outer section  60  of the baffle  52  may extend around the inner section  62  of the baffle. A plurality of connectors  70  may extend between the outer and inner sections  60  and  62  of the baffle  52  and hold them against movement relative to each other. The connectors  70  may be releasable to enable the inner section  62  of the baffle  52  to move downward relative to an outer section  60  of the baffle  52  to increase the size of an opening through which the mold, moves from the heating chamber  44 . 
     The connectors  70  may extend between the outer and inner sections  60  and  62  of the baffle  52  and retain one or more side surfaces  76 ,  78 ,  92  and/or  94  on the outer and inner sections  60  and  62  of the baffle in a coplanar relationship when the mold  34  is in the heating chamber  44  of the furnace assembly  22 . The connectors  70  may be releasable under the influence of force transmitted from the mold  34  to enable the inner section  62  of the baffle to move downward relative to the outer section  60  of the baffle  52 . 
     The baffle  52  may be formed as one-piece (FIGS. 2-5) with the connectors  70  integrally formed as one-piece with the outer and inner sections  60  and  62  of the baffle  52 . The connectors  70  may be broken under the influence of force transmitted from the mold  34  to the baffle  52  during lowering of the mold from the heating chamber  44 . If desired, the outer and inner sections  60  and  62  of the baffle  52  may be separated by a plurality of slits  74  with the connectors  70  disposed between end portions of the slits  74  and formed of the same material which forms the outer and inner sections  60  and  62  of the baffle. 
     The outer and inner sections  60  and  62  of the baffle  52  may be formed as separate pieces (FIGS.  6 - 11 ). If this is done, the inner section  62  of the baffle may initially be disposed in an opening  130  in the outer section  60  of the baffle and held in its initial position by a plurality of connectors ( 70   a ,  70   b ,  70   c  or  70   d ) which extend between the outer and inner sections of the baffle. The connectors ( 70   a ,  70   b ,  70   c  or  70   d ) are releasable to enable the inner section ( 62   a ,  62   b ,  62   c  or  62   d ) of the baffle to move downward out of the opening  130  in the outer section of the baffle as the mold  34  is moved from the heating chamber  44  of the furnace assembly  22 . 
     The inner section  52   e  (FIGS. 10 and 11) of the baffle may be disposed above and at least partially supported by the outer section  60   e  of the baffle  52   e . If this is done, the inner section  62   e  of the baffle may be moved downward through an opening  130   e  in the outer section  60   e  of a baffle to increase the size of an opening through which the mold  34   e  is moved from the heating chamber. 
     Although the baffle  52  may be connected with a furnace assembly  22  in many different ways, it is believed that it may be desired to utilize latches  170  (FIGS. 12-14) to connect the baffle with the furnace assembly. The outer section  60  of the baffle  52  may be moved into engagement with and move the latches  170  during movement of the baffle into the heating chamber  44  in the furnace assembly  22 . The latches  280  are effective to retain the outer section  60  of the baffle  52  against downward movement relative to the furnace assembly during movement of the mold  34  out of the heating chamber  44  in the furnace assembly  22 . 
     The present invention has a plurality of different features which may be used together or separately. One or more of the features of the present invention may be utilized in association with one or more features of the prior art.