US3265348A

US3265348A - Mold purging apparatus and method

Info

Publication number: US3265348A
Application number: US413132A
Authority: US
Inventors: Edmund Q Sylvester
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-11-23
Filing date: 1964-11-23
Publication date: 1966-08-09
Anticipated expiration: 1983-08-09
Also published as: FR1454354A; CH442633A; DE1267801B; ES319873A1; BE672678A; AT268571B; LU49872A1; NO115182B; GB1094866A; NL6515173A; JPS523889B1

Description

United States I Patent 3,265,348 MOLD PURGING APPARATUS AND METHOD Edmund Q. Sylvester, Shaker Heights, Ohio Filed Nov. 23, 1964, Ser. No. 413,132 7 Claims. (Cl. 249109) The present invention relates to apparatus and method for purging molds of air and any other gases by the introduction of an inert gas into the mold and consequent displacement ofthe air and other gases.

A broad object of the invention is to provide novel apparatus and method for introducing the inert gas, which may be argon, into the mold. The argon is heavier than air and when the mold is purged of air and other gases by argon, the argon remains in the mold against any tendency to displace it by other gases.

One difiiculty that has been encountered heretofore in purging molds by inert gas such as argon is that upon introduction of the argon a turbulence is created and the argon mixes with the air, and an inefiicient purging operation resulted.

Another object of the present invention is to provide means and method for introducing a purging gas into a mold in such a way that it flows at the same rate in all portions of the mold and thereby substantially eliminates turbulence, resulting in a highly efficient purging operation.

A still further object is to provide novel apparatus and method for purging a mold by the introduction of a purging gas at the bottom thereof and which provides for effectively closing the bottom opening through which the purging gas is introduced but which enables effective introduction of molten metal to be cast through that bottom opening without losing any of the purging gas therethrough.

More specifically an object is to provide apparatus and method of the character just mentioned wherein a disintegrateable closure member is utilized for closing the bottom opening in the mold means, the mold means having a passage therethrough for introducing purging gas through the bottom opening, the closure member yielding for enabling this step, and the closure member disintegrating in the operation of bottom pouring into the mold.

Other objects and advantages of the invention will appear from the following detailed description taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a vertical sectional view through apparatus made according to the present invention; and

FIGURE 2 is a small scale view of the components of FIGURE 1, partially in elevation and partially in section, in partially separated position.

Referring now in detail to the drawings the apparatus shown includes an ingate construction indicated generally at 12, a mold 14, thereabove and a pressure pouring tube 16 in pouring relation to the ingate construction. The mold 14 and the pouring tube 16 may be of conventional construction and the features of the present invention are incorporated in the ingate construction 12.

The mold 14 includes a body made up of a plurality of blocks 18 which may be of graphite and which define a casting cavity 20. The pouring tube 16 includes a shank 22 and a head 24 having a tapered upper surface 26 adapted for engagement with a corresponding element of the ingate construction 12. The pouring tube 16 includes a liner 28 preferably of ceramic material which defines an annular pouring passage 30. As will be understood, the pouring tube 16 is utilized with a ladle in an arrangement in which superatmospheric pressure is applied to the ladle which forces molten metal therein upwardly through the pouring tube, through the ingate construction 12 and into the cavity of the mold.

Reference is now madeto the ingate construction 12. This ingate construction is provided with a vertical passage 32 for the passage of molten metal therethrough, which in the assembly with the mold and pouring tube registers and communicates with the passage 30 in the pouring tube and the cavity 20 in the mold. The ingate construction includes a number of members which may be conventional and found in other ingate constructions heretofore known; it includes a chill block 34 which may be of metal and which directly supports the mold 14 and functions to increase the cooling rate of the mold.

The chill block 34 is provided with a central aperture 35 in which a ceramic liner 36 is disposed defining a portion of the passage 32. -Next below the chill block 34 is a slide 38 guided by guide bars on opposite sides thereof, the arrangement being that the slide may be operated from the exterior for movement between open position (shown in the drawings) and closed position. This slide arrangement is conventional and it is believed unnecessary to show additional details thereof. It is moved between open and closed positions in directions perpendicular to the paper. The slide 38 is provided with an aperture 41 also having a ceramic liner 42 which defines another portion of the passage 32. The movement of the slide is suificient to move the aperture therein entirely out of registration with the remainder of the passage. Next below the slide is a gate assembly piece 44 having an aperture 45, in'which is disposed a ceramic liner 46 defining a third portion of the passage 32.

The foregoing members of the ingate construction are together supported by the lowermost member which is the spout receptacle 48, all of the members of the ingate construction being suitably secured together in a rigid assembly by suitable conventional means.

The spout receptacle 4-8 includes a main plate like portion 50 depending from which is an annular extension 52 which defines a recess 54 having a tapered surrounding wall 55 and an annular top surface 57 which also constitutes a bottom surface of the spout receptacle. recess 54 receives the head 24 of the pouring tube and the surface 55 engages the surface 26 thereof.

The spout receptacle 48 is provided with an aperture 58 in which is disposed another ceramic liner 59 defining the fourth and lowermost portion of the passage 32. The spout receptacle 48 is provided with a radial bore 59' at the outer end of which is suitably connected a line 60 leading from a source of the purging gas such as argon. Preferably this line 60 is provided with a quick disconnect arrangement 62. The bore 59 leads into a downwardly directed bore 64 which opens through the surface 57 of the recess 54. The surface 57 is counterbored at 68 of such radial dimension :as to extend into the vertical bore 64. Positioned in this counterbore 68 is an annular ring 70 secured thereto by suitable means such as screws 72. This ring terminates outwardly at 74 in line with the radially inner surface 76 of the vertical bore 64 so as to leave an annular passage 78 which communicates with the vertical bore 64 and provides an annular passage completely around the recess 54 and opening downwardly through the surface 57.

Secured to the surface 57 is a member for closing the lower end of the passage 32 and thus closing the mold. This member is in the form of a diaphragm 80 which may be paper or other quickly disintegrateable material. The diaphragm is held in place by a snap ring 82 yieldingly held in a circumferential groove 84 formed in the upper extremity of the tapered surface 55. The margin-al edge of the diaphragm is placed in the groove and the snap ring snapped in place thereover to hold the diaphragm in place. An annular gasket 86, which may be of asbestos, is secured to the diaphragm as by cementmg.

The

In the practical operation of the apparatus the argon under suitable pressure is introduced through the line 60 and bore 59'. It flows downwardly through the bore 64 and into the annular passage 78, and then works against the diaphragm and flexes it downwardly (including thegasket 86) to the dotted line position of FIGURE 2, providing a complete circular space establishing communication with the passage 32. The argon forces the air and all other gases ahead of it and forms a column of pure argon in the passage 32 pushing the gases upwardly. In keeping with a principal advantage of the invention the argon is introduced at a rate sufiiciently low to prevent turbulence with the air. One of the features working to this end is the introduction of the argon from all directions to the passage 32, i.e., in the space directly above the diaphragm when the diaphragm is fixed downward. The flow of argon is continued in such rate as to continuously maintain a column of pure argon which forces the air and all other gases out of the mold.

In the step of introducing the argon the ingate construction 12 is either removed from the pouring tube, or spaced upwardly therefrom (FIGURE 2) a sufficient distance to enable the diaphragm to be flexed downwardly and after the purging step has been completed the ingate construction with the mold is lowered, or if desired the pouring tube raised, to establish proper pouring engagement. In addition to the engagement of the tapered surface 55 with the pouring tube head, the gasket 86 provides additional sealing engagement between the surface of the recess and the pouring tube.

Upon the molten metal, such as steel, rising in the pouring tube it engages the diaphragm and disintegrates it. In the case of paper the paper is burned. However, the diaphragm maybe made of any of various materials, for example, aluminum foil which is readily and quickly melted by the molten metal.

While I have disclosed herein a certain preferred form of the invention, it will be understood that changes may be made therein within the scope of the appended claims.

I claim:

1. Mold means having a bottom pouring opening, a bottom surface through which said pouring opening opens, a purging gas passage for introducing inert gas into said mold, saidpassage opening through said bottomsurface adjacent .to but offset from said bottom pouring opening, and means for closing said bottom pouring opening, said closing means disintegrateable by material poured into the mold for cast-ing and being secured to said bot-tom surface in covering relation to both the pouring opening and said purging gas passage and is enabled to yield and spread from said bottom surface in response to gas introduced through said purging gas passage whereby to form an open space between the closing means and said bottom surf-ace establishing communication between said purging gas passage and pouring opening.

2. The invention set out in claim 1 wherein said botto surface includes an annular groove therein communicating with said purging gas passage forming an extension thereof opening through said bottom surface whereby when the closing means is separated from said bottom surface, gas is enabled to flow from said purging gas passage into said space radially inwardly in all directions.

3. The invention set out in claim 2 in which the closing means is burnable.

4. Mold means adapted for use in bottom pressure pouring casting comprising a mold having a downwardly opening cavity, ingate construction below and supporting the mold and having a pouring passage therethrough in register with and communicating with the cavity, the passage opening downwardly through the, ingate construction and the ingate construction including a spout receptacle as a lowermost element having a recess including a surface in its upper portion defining a bottom surface of the ingate construction and surrounding said passage, the spout receptacle also including a downwardly extending annular projection defining -a downwardly and outwardly tapering surrounding wall of the recess, the ingate construction having a radially inwardly extending purging gas passage opening downwardly through said annular bottom surface adjacent to but spaced from said pouring passage, and a disintegrateable diaphragm covering said bottom surface and covering said pouring passage and purging gas passage, means releaseably securing the marginal edge of the diaphrgam to said downwardly tapering wall adjacent said bottom surface, said diaphragm being yieldable in response to introduction of inert gas under pressure through said purging gas passage whereby to provide a space between itself and said bottom surface continuous from the purging gas passage to the pouring passage.

5. The invention set out in claim 4 wherein an annular gasket is secured to said diaphragm in surrounding relationship'to said pouring passage and effective for establishing sealing relation between an upper surface of a vertical pouring tube and said bottom surface when said pouring tube is introduced into said recess.

6. A method of casting in conjunction with mold means having a cavity and a downwardly opening passage communicating with the cavity, comprising closing the bottom open end of the passage with a disintegrateable closure, introducing inert gas into said passage from the bottom of the passage above said closure and continuing the introduction of the inert gas sufficiently to fill the passage and cavity and at a rate of flow sufliiciently low to eliminate turbulence and mixture between the inert gas and air, and pouring molten casting material into the mold by pouring it against the disintegrateable closure and thereby disintegrating it, and continuing the pouring step until the mold is filled.

7. The invention set out in claim 6 wherein the inert gas is introduced into the passage by directing it into that passage radially inwardly in all directions.

References Cited by the Examiner UNITED STATES PATENTS 674,341 5/1901 Lustig 22-214 2,082,588 6/ 1937 Menetry 22-69 2,521,362 9/1950 Grausan 222l4 2,912,728 11/1959 Sylvester 2269 3,142,099 7/1964 Burch 22-214 3,163,897 1/ 1965 Sylvester 22-69 J. SPENCER OVERHOLSER, Primary Examiner. MARCUS U. LYONS, Examiner.

Claims

6. A METHOD OF CASTING IN CONJUNCTION WITH MOLD MEANS HAVING A CAVITY AND A DOWNWARDLY OPENING PASSAGE COMMUNICATING WITH THE CAVITY, COMPRISING CLOSING THE BOTTOM OPEN END OF THE PASSAGE WITH A DISINTEGRATEABLE CLOSURE, INTRODUCING INERT GAS INTO SAID PASSAGE FROM THE BOTTOM OF THE PASSAGE ABOVE SAID CLOSURE AND CONTINUING THE INTRODUCTION OF THE INERT GAS SUFFICIENTLY TO FILL THE PASSAGE AND CAVITY AND AT A RATE OF FLOW SUFFICIENTLY LOW TO ELIMINATE TURBULENCE AND MIXTURE BETWEEN THE INERT GAS AND AIR, AND POURING MOLTEN CASTING MATERIAL INTO THE MOLD BY POURING IT AGAINST THE DISINTEGRATEABLE CLOSURE AND THEREBY DISINTEGRATING IT, AND CONTINUING THE POURING STEP UNTIL THE MOLD IS FILLED.