US1823180A

US1823180A - Method of and apparatus for forming graphite molds or other refractory articles

Info

Publication number: US1823180A
Application number: US346287A
Authority: US
Inventors: Harold E White; Hess John; Oscar E Neuhausen
Original assignee: LAVA CRUCIBLE Co
Current assignee: LAVA CRUCIBLE Co
Priority date: 1929-03-12
Filing date: 1929-03-12
Publication date: 1931-09-15
Anticipated expiration: 1948-09-15

Description

p 15, 1931- H. E. WHITE ET AL 1 METHOD OF AND APPARATUS FOR FORMING GRAPHITE MQLDS OR OTHER REFRACTORY ARTICLES Filed March 12, 1929 m m "mam W3 m2 3% ea 4 6 my 0 Patented Sept. 15, 1931 UNITED STATES PATENT errics HAROLD E. WHITE, OF BUTLER, AND JOHN HESS AND OSCAR E. NEUHAUSEN, OF

ZELIENOPLE, PENNSYLVANIA, ASSIGNORS TO LAVA CBUCIBLE COMEANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA METHOD OF AND APPARATUS EoR FORMING GRAPHITE Home on oTHER REFRACTORY ARTICLES Application filed March 12, 1929. Serial No. 346,287.

Our invention relates to the method of and apparatus for forming graphite molds or other refractory articles, and particularly to the manufacture of hollow cylindrical molds and having one end thereof closed and the other end opened, and of considerable height or depth.

In the making of molds of the general type of the present invention. two methods have heretofore been followed; first, by spinning on a rotating jigger machine; and, second, by pressing sections and afterwards uniting the sections. Under the first method stated, it has been impossible to form molds of considerable height, due to the inability to operate a tool inside the mold throughout its height or length, and the second method is obj ectionable in that it has been impossible to form satisfactory sectional molds.

The prime object of our invention is to provide a new and improved method of manufacture of molds of the character stated, in one piece and of uniform structure, and the provision of new and improved apparatus by which our method of making the molds or other hollow refractory articles may be prac ticed.

In the accompanying .drawings, which illustrate a new and improved mold'forming apparatus by which our method of making hollow elongated molds may be carried out:

Fig. 1 is a vertical sectional View through an apparatus embodying our invention, showing a. portion of some of the parts in elevation, and the relative positions of the parts at the beginning of the method;

2, a view similar to Fig. 1, showing the parts in final position; and

Fig. 3, a sectional view on the line III- TH ofFig.2.

Referring to the drawings, we have shown our apparatus in connection with a pneumat ically operated jarring machine A,of the usual or any preferred type; as shown, the jarring machine includes a table 2, a piston 3, and a cylinder 'e having a hardened strike ing or contacting surface 5.

Our apparatus is designed to be mounted on the jarring table, and as illustrated com prises a forming mold 6 preferably includ elongated casing, said split rings 9 being provided with fastening bolts 10.

The forming mold is preferably provided with an inner cylindrical hollow member or tube 11 formed of thin sheet copper or aluminum, said tube constituting a lining for the mold, and is designed to receive the article forming material, the inside diameter of said tube being substantially the same as the outside diameter of the graphite mold or other hollow article to be formed.

12 designates a closure cap for the upper end of the forming mold. This cap is provided with a central opening 13, the walls of which constitute guide means for a cylindrical plunger hereinafter described. In addition to the central opening 13, the closure cap 12 is provided with a plurality of openings 14 designed to receive rods 14a carried by the plunger and hereinafterrmore fully described. 0 The forming mold is positioned and maintained in position on thejarring table 2 by means of a holding ring 15 and a series of bolts 16 projecting therethrough and having their screw threaded ends entered in threaded sockets in the table. It is obvious, however, that the forming mold may be secured to the table by any suitable means.

Mounted for operation within the forming mold, we provide a gravity operable material piercing plunger 17 of cylindrical form and having a central bore 18 extending throughout'the length of the plunger. This plunger 17 is preferably provided with a thin metallic covering or tube indicated at 6, formed of thin sheet copper or aluminum.

The lower end of the plunger is closed bya plug 19 adapted to be threaded thereto, as shown at 20.

Said plug 19 is provided with an air passage 21adapted to be controlled by a springpressed valve 22. The opposite end of the hollow piercing plunger 17 is provided with .a cap 23 having a centrally disposed threaded depending portion 24 adapted to be. entered within the hollow plunger and secured to the interiorly threaded portion thereof. Cap 28 is formed with a central opening 26 communicating with the bore of the plunger, and is further provided with openings 27 adapted to receive rods 14a passed therethrough and designed to be passed through the closure cap 12 of the forming mold, for the purpose of engaging a gravity operable weighted follower 29 associated with the hollow plunger and arranged Within the forming mold.

It will be noted that the outside diameter of the piercing plunger 17 is considerably less than the inside diameter of'the'forming mold or the lining thereof, and that the fol lower 29 is of such diameter as to have a sliding contact with the interior of the tubular lining 11. The follower 29 is formed with threaded sockets 30 adapted to receive the l threaded ends of the rods 14a when the follower and the head or cap 23 of the plunger are in the position shown by Fig. 2. By means of this construction, itwill be noted that the heads or

caps

12 and 23 of the forming mold and the plunger, together with the follower, may be raised free of the forming mold after the completion of the mold being formed.

In the manufacture of graphite molds under our process, the mold forming material is deposited in the forming mold, filling the lower portion thereof and extending, for instance, up to the line hh of Fig. 1. In making these molds, a mixture consisting of substantially percent natural graphite, 35 percent refractory clay, and 15 percent silicon carbide fines may be employed. Water is added to this material, and it is mixed until the desired plasticity is obtained. After proper aging and remixing, a suitable quantity of mixture in an unconsolidated state is then introduced to the molding apparatus, as stated above. After the intro duction of this mixture, the plunger and the associated follower are positioned within the forming mold and assume the position shown by Fig. 1.

Ourmethod contemplates forming the unconsolidated plastic material or mixture into a thoroughly compacted homogeneous mass of the desired configuration, by the combined action of jarring and displacement of the material while subjected to pressure, and our method may be advantageously followed by the employment of the apparatus iereinaoove described.

The parts of the apparatus being in the position shown by Fig. 1. with the desired measured quantity of material P deposited 3 in the forming mold, the jarring machine is started and the heavy gravity-operated plunger will gradually descend into the material, forcingit upward into the space between the outer surface of the plunger and the inner surface of the forming mold or its tubular lining. The upward flow 0f the material is against the downward pressure exerted by the follower resting on the upper surface of the material or mixture. Continuing the operation, the follower is raised into the position near the top of the. forming mold as shown by Fig. 2. Any surplus of mixture may be discharged through a take-out opening shown at (Z. This opening may also be employed to permit the escape of air at the start of the operation.

After a mold is formed in the manner described and when the follower is in the position shown by Fig. 2, the rods 14a may be inserted to engage the follower, whereby the plunger and the follower may be lifted free of the forming mold as a unit, thus releasing the pressure on the finished article without rupturing. As the plunger is withdrawn, apartial vacuum may be created within the cavity of the hollow article being formed, and in order to relieve this, we have provided the spring-pressed valve 22 operable to admit air.

After the removal of the plunger, etc, as above described. the outer casing of the forming mold is separated from its tubular lining by loosening the encircling clamps, after which the tube with the contained green mold are placed on a drying floor. When sufficiently dry, the aluminum or copper tube or casing is removed from the formed article and may be re-used.

For the purpose of guiding and maintaining the plunger 17 in the desired operative position, we have provided a tubular member 31 having an end screw-threaded and entered in and secured to the threaded wall of openin 13 of the cap 12.

We claim:

1. The method of making a hollow refractory article which consists in placing an unconsolidated mixturein a container, jarring the mixture and displacing the mixture by the piercing action of a forming tool to cause a flow thereof upwardly in the container while pressure is applied to the upper surface of the upwardly flowing mixture exterior of the forming tool.

2. The method of making a hollow refractorv article which consists in placing an unconsolidated plastic mixture in a container. simultaneously iarring and piercing the mixture in the container while pressure is applied to the upper surface of the mixture characterized in that the mixture is caused to flow upwardly within the container by a gravity-operated piercing tool and that pressure is applied to the upper surface of the flowing mixture exterior of the piercing tool.

3. The method of making a hollow refractorv article which consists in placing an unconsolidated plastic mixture in a container, simultaneously jarring and flowing the mixture-in the container while pressure is applied to the upper surface of the mixture characterized in that the mixture. is caused to flow upwardly within the container by a gravity operated piercing tool and that pressure is applied tothe upper surface of the flowing mixture exterior of the piercing tool by a gravity-operated member, and that the material is subjected to substantially the same pressure during the piercing action by the piercing tool and said member.

4. In apparatus for forming hollow refractory articles, a forming mold intowhich the article-forming material is deposited, a gravity operable plunger movable within the mold to displace and compress the contained material, and a gravity operable follower associated with the plunger and disposed within the forming mold.

5. In apparatus for forming hollow refractory articles, a forming mold into which the article-forming material is deposited, a grav ity operable plunger movable within the mold to pierce and compress the contained material, and a gravity operable follower associated with the plunger and disposed within the forming mold, said plunger having an outside diameter considerably less than the internal diameter of the mold and said follower having 7 an outside diameter substantially equal to the internal diameter of the mold.

6. In apparatus for forming hollow refractory articles, a forming mold comprising a cylindrical divided casing having a removable liner into which the article-forming material is deposited, a closure cap for said mold having guiding means thereon, a gravity operable plunger movable within the mold and guided by the cap to pierce and compress the contained material, and a gravity operable follower associated with the plunger and disposed within the liner.

7. In apparatus for forming hollow refractory articles, a forming mold into which the article-forming material is deposited, means for positioning the forming mold on a jarring table, a hollow cylindrical gravity operable. plunger movable within the mold to pierce and compress the contained material, valve means carried at the lower end of the hollow plunger, and a gravity operable follower associated with the plunger and disposed within the forming mold.

In testimony whereof we afiix our signatures. V

HAROLD E. WHITE. JOHN HESS.

OSCAR E. NEUHAUSEN.

CERTIFICATE OF CORRECTION.

Patent No. 1,823,180. Granted September 15, 1931, to

HARGLD E. WHITE ET AL.

It is hereby certified that the name of the assignee in the above numbered patent should have been Written and printed as Lava Crucible Company of Pittshnrgh, of Pittsburgh, Pennsylvania, a corporation of Pennsylvania, instead of "Lava Crucible Company, of Pittsburgh, Pennsylvania, a corporation of Pennsylvania", as shown by the records of assignments in this office; and that the said Letters Patent should be read with this correction therein that the same may eonform to the record of the case in the Patent Office.

Signed and sealed this 3rd day of November, A. D. 1931.

M. J. Moore,

(Seal) Acting Commissioner of Patents.