US3088724A

US3088724A - Metal pouring valve

Info

Publication number: US3088724A
Application number: US136359A
Authority: US
Inventors: Sluis Jay L Vander
Original assignee: Howe Sound Co
Current assignee: Howmet Turbine Components Corp; Howe Sound Co
Priority date: 1961-09-06
Filing date: 1961-09-06
Publication date: 1963-05-07
Anticipated expiration: 1980-05-07

Description

May 7, 1963 .1. L. VANDER SLUIS 3,038,724

METAL POURING VALVE Filed Sept. 6, 1961 mmvron. Jay Z. Vander .SZzzis 3,088,724 METAL POURING VALVE Jay L. Vander Sluis, Grand Haven, Mich, assignor to Howe Sound Company, New York, N.Y., a corporation of Delaware Filed Sept. 6, 1961, Ser. No. 136,359 14 Uaims. (Cl. 266-38) This invention relates to a metal pouring valve, and it relates more particularly to a valve mechanism and an associated assembly which enables the production of castings which are substantially free of nonmetallic inclusions, dross and other objectionable materials.

It is well known that in the pouring of metal, whether for the production of castings and ingots or for other purposes, there will ordinarily be carried with the metal various inclusions. It is also well known that such inclusions can materially affect the quality of various metal products insofar as strength, ductility, fatigue life and other properties are concerned. Furthermore, in the case or ingots, subsequent working procedures can be greatly handicapped where the metal contains various inclusions.

In some instances the art has been forced to reject large amounts of production items or to simply live with poor quality products. In other cases degasing operations, vacuum casting techniques and other procedures have been resorted to to improve the casting quality and to decrease the likelihood of build up of harmful nonmetallic inclusions. These techniques, while greatly improving casting quality, are inherently expensive and time consuming and require relatively complicated mechanisms and extreme care in their application.

It is, therefore, an object of this invention to provide an improved means for avoiding the presence of harmful inclusions in molten metal which is being introduced into molds or other receptacles.

It is a further object of this invention to provide a valve mechanism for use in connection with the pouring of molten metal whereby the metal will be available for use in a condition free of various harmful inclusions.

It is an additional object of this invention to provide a check valve and a corresponding process for the use thereof which will decrease the amounts of harmful inclusions in metal being poured, whether or not the metal has been subjected to prior purifying operations.

These and other objects of this invention will appear hereinafter and for purposes of illustration, but not of limitation, specific embodiments of this invention are shown in the accompanying drawings in which FIGURE 1 is an elevation view in section of the valve mechanism of this invention as it appears assembled in a pouring cup;

FIGURE 2 is a top plan view of the check valve of this invention; and

FIGURES 3, 4 and 5 represent detail views of the various retaining and connecting means employed in conjunction with the improved check valve.

The present invention provides a valve means which relies in its operation upon the fact that various harmful inclusions contained in molten metal will rise to the surface of the metal if it is permitted to settle for a given period prior to entry into a receptacle associated with the valve. Thus, in the operation of this invention a mold assembly is provided which includes means for holding molten metal to be introduced into a receptacle such as a casting mold. The check valve of this invention is located in the passageway between the holding means and the receptacle whereby metal introduced into the holding means will be retained therein until the valve is opened.

The valve of this invention, which is designed for retaining the molten metal in the holding means, comprises States atent a first upper disc of heat resistant material having passage means therein for passage of molten metal. A second disc, also having passage means therein, is connected immediately below the first disc in a manner such that the passage means in the first disc are closed oif. The means which connect the discs are adapted to be disconnected responsive to the presence of molten metal above the valve. Therefore, after the metal is poured, the discs will eventually be disconnected, the passages in the first disc will be unblocked and the metal will then proceed through the valve to the receptacle.

Therefore, in employing the mechanisms of this invention, molten metal will be introduced into a holding means or pouring cup which has placed therein a valve of the type described. The connecting means will be adapted for causing opening of the valve after a predetermined time. During this time, inclusions in the metal will rise to the top of the pool of metal and therefore when the time has elapsed the molten metal which passes through the valve will be substantially free of the inclusions. It will, of course, be necessary to introduce suflicient metal into the holding means whereby the inclusions will not also pass into the mold or receptacle associated with the holding means. Alternatively, means could be provided for skimming oif the objectionable material as it rises to the surface.

An assembly 10 embodying the characteristics of this invention is shown in FIGURE 1. The assembly includes a holding means :12, shown in the form of a pouring cup having a neck 14 which comprises a passageway to a mold or other receptacle 16. The cup 12 is provided with a tapered wall portion 18 upon which the upper disc 20 of the check valve 22 (FIGURE 2) is supported. The edges of the disc 20 are beveled to mate with the tapered wall 18 thus providing an elfective seal at this point between the upper and lower portions of the cup.

A lower disc 24 is connected to the upper disc by means of connecting means 26. Apertures 28 are provided in the upper disc and it will be noted that when the discs are connected the lower disc blocks off the apertures 28. A central aperture 30 is provided in the lower disc 24, this central aperture being out of communication with the apertures 28 when the discs are connected.

The pouring cup 12 is preferably provided with a lip 32 whereby an annular recess 34 is provided along the bottom of the cup. As indicated by the dotted lines in FIGURE 1, the lower disc 24 will rest upon the lip 32 when it is disconnected from the upper disc, and the recess 34 avoids misalignment of the disc which could result if the connecting means 26 contacted the bottom of the pouring cup.

FIGURE 3 illustrates a hollow support 36 which is adapted to retain the lower disc 24 in position with respect to the upper disc 20. The retaining means 36 stands in the recess 34 and is provided in lieu of connecting means 26.

FIGURE 4 illustrates an alternative connecting means 38 comprising a hollow tubular element having crimped ends 40. The connecting means 42, shown in FIGURE 5, comprises a further alternative connecting means composed of a hollow tubular element having a closed end 44. Crimped end 46 thereof provides for retaining of the

discs

20 and 24 in the position shown.

The connecting means shown in FIGURE 1 comprises a screw and nut assembly 26 which serve to secure the

discs

20 and 24 with respect to each other. When pouring molten metal with a disc connected by a means such as the means 26, the molten metal will cause deterioration of the nut of the assembly and the lower disc will thus eventually drop to the dotted line position shown. Obviously, molten metal introduced into the pouring cup will build up therein a positive head pressure prior to opening of the valve. During the interval between pouring and opening of the valve, nonmetallic inclusions, dross, etc., in the molten metal will rise to the surface of the melt. Accordingly, metal passed through the valve after opening thereof will be free of these inclusions and a product of higher quality can be obtained.

Where a retaining means, such as shown at 36 in FIG- URE 3, is employed, the initial portions of molten metal introduced into the cup 12 will pass through opening 59 and into the hollow member 36. After a given time interval, the member 36' will be caused to deteriorate and the lower disc 24 will drop, thus opening the valve assembly. Similarly, the presence of molten metal will affect connecting means 38 and 42, shown in FIGURES 4 and 5. With connecting means'of this type the effect of the hot metal combined with the pressure set up by the head of metal will serve to disconnect the respective discs.

As anexample of a suitable arrangement, a ceramic disc corresponding to the disc 20 and having a 3 /8 in. base diameter was connected to a 3% in. diameter ceramic disc corresponding to the disc 24. in. metal screws held the discs together and with an assembly of this'size, pouring of alloys into a cup such as the cup 12 will result in a duration of several seconds prior to decomposition of the exposed portions of the screws. Upon decomposition of these portions, the lower disc will drop, opening the valve, and, of course, the metal passing therethrough will be substantially free of nonmetallic inclusions. In selecting material for the screw connecting members, it is desirable that the material be of approximately the same composition as the metal being poured to insure deterioration of the connecting means within a desired period.

The materials used for the discs and 24 are preferably selected from strong, highly refractory, metallic or nonmetallic materials in order that the discs will not readily deteriorate after contact with molten metal whereby they can be re-used by simply replacing the connecting means therefor. The connecting or retaining means can be manufactured from any material which is decomposable or destructible, in whole or in part, when in proximity with the pressure and heat of the metal being cast. Use of the same material as that being cast is a suggested possibility, since the molten metal will ordinarily be poured at a temperature considerably above the melting point for the metal and will, therefore, melt the solid metal when exposed thereto. Other metallic and nonmetallic materials may be selected; however, in many cases, it will be necessary to provide a material which is compatible with the metal being cast whereby the ultimate product will not be unduly contaminated.

It will be obvious that the amount of time which will elapse before the connecting or retaining means deteriorates will be dependent upon several factors. For example, the heat of the material being poured as well as the melting point or deterioration point of the connecting means can be varied in order to increase or decrease the duration between pouring and opening of the valve. Furthermore, the type of connecting means employed and the size of these components are factors to be considered. It will, therefore, be understood that specific material and design specifications are not intended to be provided by the above recitations, since any given casting operation will be determinative of a particular need.

It will be apparent that there has been provided an improved means whereby nonmetallic inclusions will be permitted to rise to the surface of metal being poured prior to the time the metal is introduced into a mold or I similar receptacle. The valve design of this invention also permits a monitored rate of flow of the metal into the mold since the valve orifice sizes can be varied in addition to the metal dwell time. The metal is introduced into the mold with a minimum amount of turbulence in accordance with the disclosed method and this factor aids in providing oxidation free castings even when highly reactive metals such as those containing aluminum and titanium are being cast. The valves of this invention can be employed even if such alloys are being vacuum cast since some oxide inclusions would otherwise be in evidence. it is, of course, essential that defects of this nature be completely eliminated in highly critical cast components for aircraft and missile applications, and this in vention is considered a valuable supplement to conventional processing in this area. However, the use of this invention is intended to be applicable to any type of receptacle wherein metal is poured for solidification therein or'for other purposes. The system of this invention is considered to be particularly valuable in conjunction with sand molds, ceramic shell molds, resin shell molds and metal molds as well as in conjunction with the casting of metal ingots into ingot molds.

Various modifications in the above disclosed 'valve system will be obvious to those skilled in the art. For example, the particular designs shown could be inverted whereby a central orifice could be formed in the upper disc while'the lower disc is provided with a plurality of openings. Furthermore, the connecting means for the disc could consist of a single means positioned centrally of the discs with the orifices spaced therearound. It will be apparent that many designs of the openings and connecting means are feasible and within the scope of the claimed invention.

It will be understood that other modifications may be made in the above described invention which provide the characteristics of this invention without departing from the spirit thereof, particularly as defined in the following claims.

I claim:

1. A valve for use in the pouring of molten metal comprising a first upper disc of heat resistant materal having passage means therein for passage of molten metal, a second lower disc having passage means therein for passage of molten metal, means for connecting said discs, said connecting means being adapted to be disconnected responsiveto the presence of molten metal on the upper disc, and said passages being designed whereby the lower disc blocks off the passages in the upper'disc when the discs are connectedand whereby the lower disc provides a continuous-passage for the molten metal 'when'the discs are disconnected.

2. A valve according to claim 1 wherein said connecting means are formed of a heat decomposable material whereby the discs are adapted to be disconnected principally due to the'decomposition of the connecting means.

3. A valve according to claim 1 wherein said discs are composed of ceramic materials.

4. A check valve for use in' the pouring of molten metal comprising a first upper disc of heat resistant material having passage means therein for passage of molten metal, a second lower disc having passage means therein for passage of molten metal, heat decomposable connecting 'means for connecting said discs, said connecting means being adapted to be disconnected responsive to the presence of molten metal on the upper disc, and said passagesbeingdesigned whereby the lower disc blocks off the passages in' the upper disc whe'nthe discs are connected and whereby the lower disc provides a continuous passage for the molten metal when the discs are disconnected.

5. A valve according toclaim 4 wherein said connecting means comprises a screw and nut assembly and whereby one end of said assembly is exposed on said upper disc and is adapted to decompose when the molten metal is poured onto the upper disc.

6. A valve according to claim 4 wherein said connecting means comprises a hollow member passing through said discs whereby molten metal is adapted to enter and decompose the connecting means.

7. A valve according to claim 4 wherein said connecting means comprises a hollow member with a closed bottom whereby molten metal is adapted to enter and decompose the connecting means.

8. A valve for use in the pouring of molten metal comprising a first upper disc of heat resistant material having passage means therein for passage of molten metal, a second lower disc having passage means therein for passage of molten metal, means for retaining said discs in abutting relationship, said retaining means being adapted to release said lower disc responsive to the presence of molten metal on the upper disc, and said passages being designed whereby the lower disc closes off the passages in the upper disc when the discs are in abutting relationship and whereby the said passages provide for continuous passage of molten metal when the lower disc is released from the upper disc.

9. A valve according to claim 8 wherein said retaining means comprises a heat decomposable hollow member supporting said discs, said hollow member being adapted to receive molten metal and being adapted to collapse responsive to the presence of molten metal.

10. In a metal casting assembly wherein a metal holding means is positioned above a casting mold in direct communication therewith, the improvement comprising a check valve located in the metal passageway between said holding means and said mold, said check valve comprising a first upper disc of heat resistant material having passage means therein for passage of molten metal, a second lower disc having passage means therein for passage of molten metal, heat decomposable connecting means for connecting said discs, said connecting means being adapted to be disconnected responsive to the presence of molten metal on the upper disc, and said passages being designed whereby the lower disc blocks oil the passages in the upper disc when the discs are connected and whereby the lower disc provides a continuous passage for the molten metal when the discs are disconnected.

11. A valve according to claim 10 wherein said holding means is provided with means for supporting said upper disc whereby the lower disc will move away from the upper disc when said discs are disconnected.

12. In a metal casting assembly including a pouring cup and associated mold, the improvement comprising a check valve for delaying passage of molten metal from said cup to said mold whereby inclusions in said metal will rise away from the valve prior to opening thereof, said check valve comprising a first upper disc of heat resistant material having passage means therein for passage =of molten metal, a second lower disc having passage means therein for passage of molten metal, heat decomposable connecting means for connecting said discs, said connecting means being adapted to be disconnected responsive to the presence of molten metal on the upper disc, and said passages being designed whereby the lower disc blocks 01? the passages in the upper disc when the discs are connected and whereby the lower disc provides a continuous passage for the molten metal when the discs are disconnected.

13. A valve according to claim 12 wherein said pouring cup is provided with a tapered wall portion and said upper disc extends to said wall and is beveled to correspond with said taper whereby it will he supported by said wall, said lower disc *being adapted to be positioned clear of said tapered wall portion whereby it will drop away from said upper disc When said discs are disconnected.

14. A valve according to claim 12 wherein said discs are formed of ceramic materials and said connecting means are formed of metal alloys substantially the same as the metal being cast.

Goldschmidt Jan. 6, 1903 Dickson Oct. 4, 1932

Claims

1. A VALVE FOR USE IN POURING OF MOLTEN METAL COMPRISING A FIRST UPPER DISC OF HEAT RESISTANT MATERAL HAVING PASSAGE MEANS THEREIN FOR PASSAGE OF MOLTEN METAL, A SECOND LOWER DISC HAVING PASSAGE MEANS THEREIN FOR PASSAGE OF MOLTEN METAL, MEANS FOR CONNECTING SAID DISCS, SAID CONNECTING MEANS BEING ADAPTED TO BE DISCONNECTED RESPONSIVE TO THE PRESENCE OF MOLTEN METAL ON THE UPPER DISC, AND SAID PASSAGE BEING DESIGNED WHEREBY THE LOWER DISC BLOCKS OFF THE PASSAGES IN THE UPPER DISC WHEN THE DISCS ARE CONNECTED AND WHEREBY THE LOWER DISC PROVIDES A CONTINUOUS PASSAGE FOR THE MOLTEN METAL WHEN THE DISCS ARE DISCONNECTED.