US 3557867 A
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United States Patent  Inventor Erich Krzyzanowski Frankenthal/Pialz, Germany 21 Appl. No. 830,326 22 1 Filed June 4, 1969  Patented Jan. 26, 1971  Assignee Grunzweig & Hartmann Aktiengesellschait Ludwigshaien (Rhine), Germany  Priority June 19, 1968  Germany  1,758,521
Continuation-impart of application Ser. No. 795,570, Jan. 31, 1969.
 CASTING APPARATUS 6 Claims, 1 Drawing Fig.
 US. Cl 164/255, 164/253, 164/34, 164/5, 164/7, 164/160, 164/169, 164/180  Int. Cl B22d 27/16  Field of Search 164/255, 253, 34, 35, 36, 5, 6,7,160,169, 180
 References Cited UNITED STATES PATENTS 1,369,182 2/1921 Moore Summy Primary Examiner -J. Spencer Overholser Assistant Examiner-V. K. Rising Att0rneyMichae1 S. Striker ABSTRACT: A casting apparatus. A body of granular material is confined in a container and a stream of gaseous fluid is introduced into the bottom of the container to impart to the granular material a state at least approaching fluidization. Into the thus-agitated material a form is introduced consisting of a material which is subject to consumption on contact with a molten metal. Admission of gaseous fluid is terminated to permit settling and compacting of the granular material about the form. Molten metal is introduced into the form to assume the configuration of the same while simultaneously consuming the form. The circumferential wall of the container is gas permeable and gaseous fluids in the container, particularly combustion gases resulting from the consumption of the material of the form, is aspirated through the gas-permeable circumferential wall to the exterior of the container,
CASTING APPARATUS CROSS-REFERENCES TO RELATED APPLICATIONS The present invention is a continuation-in-part of my copending application, Ser. No. 795,570, filed on Jan. 31, I969 under the title Method and Apparatus for Making Castings."
BACKGROUND OF THE INVENTION The present invention relates to casting apparatus, and more particularly to casting apparatus utilizing a casting mold or casting form consisting of a material which will be consumed by contact with molten metal.
In my aforementioned copending application I have set forth a method and an apparatus for making castings utilizing forms consisting of a material which will be consumed by contact with the molten metal. As there indicated, I provide a container in which I confine a body of granular material, and I thereupon admit into a bottom region of the container a stream of gaseous fluid in such a manner as to agitate the granular material and impart thereto a state which at least approaches fluidization. Thereupon I introduce the casting form into the thus-agitated granular material and terminate admission of the gaseous fluid so that the granular material settles about and into tight conformity with the casting form which latter may consist of a foam plastic or the like. Now the molten metal is introduced into the form and fills the same, assuming the configuration of the form while simultaneously consuming the material thereof. On completion of the casting the gaseous fluid is again admitted into the bottom region of the container to agitate the granular material in order to facilitate removal of the finished casting which is embedded in the body of granular material.
The apparatus disclosed in my copending application utilizes a container having a bottom wall which is gas-permeable, with a pressure-equalizing chamber being located below the bottom wall so that the gas can be introduced into this chamber and will escape from there through the gas-permeable bottom wall and into the interior of the container.
I have found this apparatus disclosed in my copending application, to be very advantageous. However, it does have one disadvantage which requires further improvement. Specifically, it is unavoidable that the hot combustion gases which develop in the interior of the container during the molding operation, be aspirated downwardly through the gas-permeable bottom wall while admission of gaseous fluid therethrough is terminated, and thus entervinto the vacuum pump which is also provided and communicates with the pressure equalization chamber for the purpose of applying through the same and through the bottom wall an underpressure to the body of granular material in order to aid in more tightly compacting the granular material about the form which has been embedded in the granular material while the same was in the fluidized state or the state approaching fluidization. Evidently, the entry of such hot combustion gases into the vacuum pump would be damaging to the latter if there are larger quantities of such combustion gases liberated. Where the apparatus is on a small scale, and only small quantities of hot combustion gases develop, the danger is relatively small but where the apparatus is on a larger scale, the vacuum pump could be prematurely destroyed. This would mean the necessity for providing filters and cooling arrangements to prevent the entry of hot combustion gases into the vacuum pump and this, in turn, would considerably increase the expense of the apparatus as well as requiring increased maintenance.
SUMMARY OF THE INVENTION It is, accordingly, a general object of the present invention to overcome this disadvantage.
More particularly, it is an object of the present invention to provide an improved apparatus of the type set forth in my above-mentioned copending application.
Still more specifically it is an object of the invention to provide such an apparatus wherein hot combustion gases are withdrawn from the interior of the container in such a manner that they cannot cause damage to any components of the apparatus.
In pursuance of the above objects, and others which will become apparent hereafter, one feature of my apparatus resides in the provision of a container having a bottom wall and a circumferential wall which is permeable to gaseous fluid. A body of granular material is confined in the container. Admitting means is provided for admitting into the container in the region of said bottom wall thereof a stream of gaseous fluid requisite for agitating the granular material to a state which at least approaches fluidization. A casting form is arranged to be introduced into the body when the granular material is in the aforementioned state, and consists of a material which is subject consumption on contact with the molten metal. Casting means is operative for casting into the form a molten metal so that the latter assumes the configuration of the form while simultaneously consuming the same. Finally, I provide removing means operative for effecting withdrawal of the gaseous fluids from the container through the circumferential wall thereof.
This prevents the hot combustion gases, or at least the major portion thereof, from becoming aspirated through the bottom wall into the vacuum pump.
The novel features of the invention which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING The single FIG. is a diagrammatic illustration of apparatus according to my present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail it will be seen that my novel apparatus comprises a container 1 bounded by wall means which includes a gas-permeable bottom wall 2 and a gas-permeable circumferential wall 10. The bottom wall 2 communicates with a pressure-equalization chamber 3 located below it, and the latter in turn communicates via a conduit 5 with a conventional three-way valve 6 of the type which is more fully discussed in my aforementioned copending application. An operating member 6a serves to actuate the threeway valve 6, and the latter can be made to connect the conduit 5 selectively via conduits 5a with either a source of vacuum or a source of gaseous fluid, both being indicated in the drawing in diagrammatic form and with legends.
As shown, the interior of the container 1 accommodates a body of granular material, and a casting form CF is diagrammatically indicated and is to be embedded in this body when the same has been placed into a state at least approaching fluidization by the admission of gaseous fluid from the source through the conduit 5 and the chamber 2 and through the bottom wall 2 into the interior of the container 1. Casting means CM, also illustrated diagrammatically, serves to introduce molten metal into the casting form CF after the same has been embedded to the necessary extent in the body of the granular material. All of this is described in more detail in my aforementioned copending application.
According to the present invention the circumferential wall 10 of the container 1 consists of gas-permeable material, for instance of highly heat-resistant porous sintered material, and the container 1 itself is surrounded by additional wall means 11 which defines with the circumferential wall 10 an enclosed space, or enclosure, identified with reference numeral 110. This enclosure lla is fluidtight and communicates with the ambient atmosphere in known manner via suitable removing means, here illustrated as a blower 12 whose intake communicates with the interior of the enclosure 1 1a and whose outlet communicates with the exterior of the wall means 11, usually with the ambient atmosphere.
It will be noted that the enclosure 11a and the chamber 3 are fluid tightly separated from one another so that any hot combustion gases which develop in the interior of the container 1 during the casting process are completely or at least substantially aspirated through the gas-permeable circumferential wall into the enclosure 11a and vented from there via the removing means 12, preventing their aspiration through the permeable bottom wall 2 into the chamber 3 and from there through the conduit 5 into the vacuum source, usually a vacuum pump.
[n this manner I provide an apparatus which in a simple and inexpensive manner improves the apparatus disclosed in my aforementioned copending application and avoids the abovediscusscd disadvantage thereof in reliable manner.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in a casting apparatus, it is not intended to be limited to the details shown, since various applications, modifications and structural changes may be made without departing in any way from the spirit of the present invention.
I. An apparatus of the character described, comprising in combination, a container having a bottom wall, and a circumferential wall permeable to gaseous fluid; a body of granular material confined in said container; admitting means for admitting into said container in the region of said bottom wall thereof a stream of gaseous fluid requisite for agitating said granular material to a state at least approaching fluidization means providing said fluid stream; a casting form arranged to be introduced into said body when said granular material is in said state, and consisting of a material subject to consumption on contact with a molten metal; casting means operative for casting into said form a molten metal so that the latter assumes the configuration of said form while consuming the same; and removing means operative for effecting withdrawal of gaseous fluids from said container through said circumferential wall.
2. An apparatus as defined in claim 1, wherein said circumferential wall is composed at least in part of sintered metal.
3. An apparatus as defined in claim 1; further comprising wall means surrounding said container and defining with the same a fluid tight enclosure; and wherein said removing means are operative for withdrawing said gaseous fluid through said circumferential wall into said enclosure and for removing the withdrawn gaseous fluid from said enclosure to the exterior of said wall means.
4. An apparatus as defined in claim 3, wherein said bottom wall also consists of material permeable to said gaseous fluid; said wall means further defining a pressure-equalizing chamber located below said wall means, and said admitting means communicating with said chamber for admitting said stream of gaseous fluid into the latter for passage through said bottom wall and into said container; and wherein said chamber and said enclosure are fluid tightly separated from one another.
5. An apparatus as defined in claim 3, wherein said removing means comprise a blower having an inlet communicating with said enclosure and an outlet communicating with the exterior of said wall means.
6. An apparatus as defined in claim 4; and further comprising a source of underpressure communicating with said chamber for aiding in settling and compacting of said granular material about said form subsequent to introduction of the latter into said body and upon termination of admission of said gaseous fluid into said container.