US3313318A - Sequentially operated plural valves for vacuum casting apparatus - Google Patents

Description

R. E. LYMAN April 11, 1967 2 Sheets-Sheet 1 Filed Jan. 22, 1964 Afiorney April 11, 1967 R. E. LYMAN 3,313,318

SEQUENTIALLY OPERATED PLURAL VALVES FOR VACUUM CASTING APPARATUS Filed Jan. 22, 1964 2 Sheets-Sheet 2 Afforney United States Patent 3,313,318 SEQUENTIALLY OPERATED PLURAL VALVES FOR VACUUM CASTING APPARATUS Richard E. Lyman, Homewood, Ill., assignor to United States Steel Corporation, a corporation of Delaware Filed Jan. 22, 1964, Ser. No. 339,437 7 Claims. (Cl. 137-63015) This invention relates to apparatus for casting metal in vacuum and, more particularly, to valve mechanism for controlling the connection between a vacuum line and the casting chamber. In a manner to be described the valve mechanism for this purpose is constructed in the form of a cartridge to facilitate its removal and replacement as a unit in the vacuum line for cleaning or repair.

Vacuum pumps for withdrawing air and gas from casting chambers in vacuum casting systems have load-pressure operating characteristics that require careful regulation of their connection to the casting chamber to prevent overloading which may result in the pumps pulling out and being rendered inoperative. Since the volume of the casting chambers is large, overloading of the pumps will result if the connection with the casting chamber is made too rapidly, particularly during starting when the system is being conditioned for a casting operation. One of the objects of the invention, accordingly, is to provide a valve of improved construction which will enable the required throttling regulation of the connection between the vacuum line and the casting chamber.

In vacuum casting apparatus of the type indicated, dirt caused by splattering metal and gases evolved while the metal is being cast necessitates periodic removal of the valve for cleaning as a normal maintenance operation. A further object of the invention accordingly is to provide a valve having a cartridge construction that facilitates, as stated above, its removal and replacement in the vacuum line. To this end, the cartridge comprises a cylindrical housing that carries all of the valve operating parts and is adapted to have telescopic engagement in one of the pipe sections of the vacuum line to mount it in operative position.

Other objects and advantages of the invention will become apparent from the following description and the accompanying drawings, in which:

FIGURE 1 is a vertical sectional view which shows the manner in which the valve is mounted in a pipe line;

FIGURE 2 is a plan view of the valve shown in FIG- URE 1;

FIGURE 3 is a vertical sectional view taken substantially along the line III-III of FIGURE 2;

FIGURE 4 is a fragmentary sectional view drawn to an enlarged scale showing the construction of the valve seat;

FIGURE 5 is a plan view which shows the arrangement of the pilot valves in the main valve throttle plate;

FIGURE 6 is an enlarged plan view of a portion of the main valve plate shown in FIGURE 5 that contains one of the pilot valves therein;

FIGURE 7 is a sectional view taken substantially along the line VIIVII of FIGURE 6;

FIGURES 8 and 9 are respectively plan and elevational views of a valve liner that forms part of the pilot valve shown in FIGURE 7; and

FIGURE 10 is a fragmentary sectional view similar to FIGURES 2 and 3, but showing a modified embodiment of the invention which omits the pilot valves of the preferred embodiment shown in FIGURES 2 and 3.

As shown in the drawings, the valve of this invention is in the form of a cartridge that comprises a cylinder 1 on which all of the essential operating parts of the valve are mounted. At its upper end the cylinder 1 has an outturned flange 2 by which it is supported on a coupling 3,313,318 Patented Apr. 1 r, 1967 flange 3 at one end of a pipe section 4 that forms part of a vacuum line for withdrawing air and gas from the casting chamber of a vacuum casting apparatus. Preferably, the pipe section 4 forms the terminal end of the vacuum line within the casting chamber, in which case the valve flange 2 is loosely supported on the pipe coupling flange 3 so that the valve may be easily removed between casting operations. If desired, the valve may be located in a portion of the vacuum line outside the casting chamber, in which case the flange 2 is bolted between the coupling flange 3 and a similar coupling flange 5 on the end of an adjacent pipe section 6. When positioned outside the casting chamber in this manner, the valve is preferably located between pipe sections 4 and 6 at a point where the vacuum line is normally separated between routine casting operations to provide for its ready removal from the section 4 when necessary. In either case, the cylinder 1 has a telescopic or slide fit in the pipe section 4 so that its internal surface 7 in effect forms a part of the pipe-line through which air and gas flows from the casting chamber to the vacuum pumps in the direction indicated by the arrows in FIGURE 1.

The valve comprises a circular throttle plate 8 and a valve seat 9 in the form of an annular flange that extends circumferentially about the lower end of the cylinder 1 and furnishes a support for an O-ring seal 10. The O-ring seal 11} provides a valve seating surface 11 that faces in an upward axial direction relative to the cylinder 1 and engages a peripheral edge portion of the throttle plate 8 when it is lowered to its closed position as shown in solid lines in the drawings. From its closed position, the throttle plate 8 travels axially upwardly with a tilting motion to an open position in a manner to be described.

Upward movement of the valve plate 8 in the cylinder 1 is effected by a pair of cables 12 that have their lower ends connected with the plate 3 in a manner to be described and their upper ends connected to winding spools 13. The spools 13 are keyed to an operating shaft 14 which has opposite ends 15 thereof rotatably supported in openings in the flange 2 at the upper end of the cylinder 1. One of the shaft ends 15 has an extension 16 for connection with a crank (not shown) for manual operation or a motor driven pulley (not shown) for effecting rotation thereof. Upon winding rotation of the spools 13 in a counter-clockwise direction as viewed in FIGURE 1, the cables 12 elevate the throttle plate 8 in the cylinder 1. If desired, the spools 13 may be omitted and the cables attached to and wound directly on the shaft 14. Initial upward movement of the throttle plate 8 in this manner operates to move it out of seating engagement with the valve seating surface 11. Disengagement of the throttle plate 8 with respect to the seating surface 11 in this manner provides for limited flow of air and gas through the annular space or clearance about the peripheral edge of the throttle plate 8.

Further upward movement of the throttle plate 8 in the cylinder 1 results in its tilting movement to open position. Tilting of the plate 8 to open position takes place about an axis parallel to the shaft 14-, and is effected by a rod 17 and a pair of diametrically opposed turning members 18 of semi-cylindrical shape that project inwardly from opposite sides of the cylinder surface 7. The rod 17 is spaced axially above the closed position of the throttle plate 8 shown in solid lines in FIGURES 1 and 3 and occupies a chordal position relative to the cylinder 1 in which it is parallel to the cable winding shaft 14. As the plate 8 is drawn upwardly by the cables 12 in the cylinder 1, it is engaged by and tilts about the rod 17 to the partially open position designated by the dotted lines in FIGURE 1. This initial tilting action continues until the throttle plate 8 engages the cylindrical surfaces of the turning members 18 over which it then travels with a sliding and further tilting movement in response to continued upward movement by the cables 12 to the fully open position designated by the dotted lines 817 in FIGURE 1. Further turning movement of the throttle plate beyond the fully open position 8b is prevented by a stop rod 20.

In the preferred embodiment of the invention shown in FIGURES l and 3 the operating cables 12 are connected at their lower ends with the throttle plate 8 through pilot valves 21 in a manner to be described. In the modified embodiment of the invention shown in FI URE 10, which omits the pilot valves 21, the lower ends of the cables 12 are connected by eyelets 22 directly to the throttle plate 8 so that initial upward movement of the cables 12 by winding rotation of the spools 13 is effective to elevate the throttle plate 8.

The pilot valves 21 are located in spaced positions along a diameter of the plate 8 that is parallel to the tilting rod 17. In addition to serving as an anchoring connection for the lower ends of the cables 12, each of the pilot valves 21 operates to provide an adjustable throttling connection for gradual reduction of the pressure on the upper or casting chamber side of the main valve plate 8 before axial upward movement is imparted thereto by the cables 12. For this purpose, and as best shown in FIGURES 7, each of the pilot valves 21 comprises a cylinder 2? that is secured at its upper end to the throttle plate 8 in a depending position arranged concentrically about an opening 24 therein. An annular valve seat 25 is secured to the lower end of the cylinder 23 for engagement with a circular valve plate 26 that is movable axially upwardly from its closed position engaged with the valve seat 25 as shown in solid lines in FIGURE 6. As shown in FIGURE 3, the cable 12 extends through an opening 27 in the valve plate 26 and has a lead weight 28 in the form of a ball at its lower end. When the cables 12 are Wound upwardly by the spools 13, the weights 28 engage and raise the valve plate 26 in the cylinder 23 out of seating engagement with the valve seat 25. A valve liner 29 is arranged about the inner surface of the cylinder 23 and has a plurality of V-shaped slots 30 therein. The slots 39 have their points 31 arranged adjacent the valve seat 25 so that they are gradually uncovered during upward movement of the valve plate 26 in the cylinder 23 to provide gradually increasing openings through which the pressure above the main valve plate 8 is gradually reduced. A stop bar 32 secured to the plate 8 in a position across the upper end of the openings 24 limits upward movement of the valve plate 26 in the cylinder 23. When the valve plate 26 moves to a position in engagement with stop bar 32, continued upward movement of the cables 12 operate to disengage the throttle plate 8 from the seat 9 as described above.

In operation, the valve is closed and the vacuum ejector pump connected with the ejector piping 4 is turned on when the casting chamber is ready for a metal casting operation as customary in vacuum casting apparatus of this kind. After this has been done, the valve is operated to connect the casting chamber piping 6 with the vacuum piping 4 and this is accomplished as explained above by rotating the winding spools 13 to draw the cables 12 upwardly in the cylindrical casing 1. In the preferred embodiment of the invention, upward movement of the cables 12 in this manner operates initially to engage the Weights 23 at the lower ends of the cables 12 with the pilot valve plate 26 and move it upwardly over the inner surface of the valve liner 29. Initial upward movement of the valve plates 26 in this manner disengages them from the annular valve seats 25 and moves the plates 26 over the lower ends 31 of the notches 30 in the liner 29 to provide an initial pilot evacuating connection with the casting chamber through the upper end of the valve as viewed in FIGURE 1. As the upward movement of the pilot valve plates 26 is continued, the size of the pilot evacuating connections through the notches 30 is increased until the valve plates 26 engage the stops 32. The speed of upward movement of the plates 26 is carefully regulated by the operator in accordance with the pumping characteristics of the e ector pumps to make certain that such pumps are not overloaded. After the valve plates 26 contact the stops 32, further upward movement of the cables 12 operates to move the throttle valve plate 8 upwardly in the cylinder 1 and to tilt it to its fully open position as explained above.

From the foregoing, it will be apparent that the valve of this invention enables the operator to carefully control the vacuum connection for the casting chamber in a manner that prevents withdrawal of air or gas from the casting chamber at a rate that will overload the vacuum pumps. Since all of the essential valve operating parts are carried by the cylinder 1, which is readily assembled with a telescopic movement in an existing pipe section 4, it will be further apparent that the valve of this invention facilitates its removal for cleaning or repair. Although a cartridge construction using the removable cylinder 1 is preferred for this reason, it will be understood that the valve may be formed in a separate housing such as the pipe section 4.

While a preferred embodiment of my invention and a modification thereof have been shown and described it will be apparent that other adaptations and modifications may be made without departing rom the scope of the following claims.

I claim:

1. A valve comprising a valve seat having an annular seating surface facing axially outwardly therefrom, a circular valve plate adapted to occupy a closed position with a peripheral edge portion thereof engaged with said seating surface, a pilot valve means on said plate comprising a cylinder having one end secured to said plate and projecting axially therefrom in a direction opposite that in which said seating surface faces, said plate having an opening therein aligned with said cylinder, a liner about the inner surface of said cylinder having Vshaped notches therein with the small ends of said notches arranged adjacent the other end of said cylinder, an annular pilot valve seat at the said other end of said cylinder in a position spaced axially beyond the said small ends of said notches, and a pilot valve plate movable axially in said cylinder and adapted to occupy a closed position at th said other end of said cylinder engaged with said annular pilot valve seat, and valve operating means operable initially to move said pilot valve plate axially toward said circular valve plate to disengage it from said annular valve seat and over said notches to provide restricted valve openings of gradually increasing dimensions between opposite sides of said circular valve plate, and thereafter to move said circular valve plate axially to move it out of seating engagement with said annular seating surface.

2. A valve for a pipe line comprising, the combination with a cylinder forming part of said pipe line, of a valve seat extending circumferentially about the inner surface of said cylinder and having an annular seating surface facing in an axial direction relative thereto, a circular valve plate adapted to occupy a closed position extending transversely of said cylinder with a peripheral edge portion thereof engaged with said annular seating surface, said plate being movable through said cylinder in said axial direction and being tiltable from said transversely extending position to an open position, a pilot valve means on said plate operable upon progressive movement to open position to provide a throttle opening of gradually increasing size through said plate, and valve actuating means for sequentially operating said pilot valve means to open position and thereafter to move said valve plate axially through said cylinder, and means in the path of axial movement of said valve plate through said cylinder for tilting it out of said transversely extend ing position to said open position.

3. A valve for a pipe line comprising, the combination with a cylindrical cartridge forming part of said pipe-line, of a valve seat extending circumferentially about the inner surface of said cartridge and having an annular seating surface facing in an axial direction relative thereto, a circular valve plate adapted to occupy a closed position extending transversely of said cartridge with a peripheral edge portion thereof engaged with said annular seating surface, said plate being movable through said cartridge in said axial direction, a pilot valve means on said plate comprising a cylinder having one end secured to said plate and projecting axially therefrom in a direction opposite that in which said seating surface faces, said plate having an opening therein aligned with said cylinder, a liner about the inner surface of said cylinder having V-shaped notches therein with the small ends of said notches arranged adjacent the other end of said cylinder, an annular pilot valve seat at the said other end of said cylinder in a position spaced axially beyond the small ends of said notches, and a pilot valve plate movable axially in said cylinder and adapted to occupy a closed position at the said other end of said cylinder engaged With said annular pilot valve seat, and valve operating means operable initially to move said pilot valve plate axially toward said circular valve plate to disengage it from said annular pilot valve seat and over said notches to provide restricted valve openings of gradually increasing dimensions between opposite sides of said circular valve plate, and thereafter to move said circular valve plate axially to move it out of seating engagement with said annular seating surface.

4. The pipe line valve defined in claim 3 characterized by means in the path of axial movement of said circular valve plate through said cylinder for tilting it out of said transversely extending position to an open position.

5. The pipe-line valve defined in claim 3 characterized by said valve operating means comprising a cable extending axially relative to said cartridge and having one end connected with said pilot valve plate for moving it to open position, means responsive to movement of said pilot valve plate to its said open position for rendering said cable effective to move said circular valve plate axially through said cylindrical cartridge, a spool on which the other end of said cable is wound, and means for rotating said spool to wind said cable thereon and operate said pilot valve and circular valve plates sequentially to their open positions.

6. The pipe-line valve defined in claim 5 characterized by there being a pair of said pilot valve means arranged on a diameter of said circular valve plate and by said valve actuating means including a pair of said cables respectively having operating connections at opposite ends thereof with said pilot valve plates and said Winding spools.

7. A valve for a pipe line comprising a cylinder having its axis extending vertically and forming part of said pipe line, an upwardly facing annular seating surface at the lower end of said cylinder, an operating shaft rotatably mounted on the upper end of said cylinder in a horizontal position extending along a diameter thereof, a circular valve plate adapted to occupy a closed position with a peripheral edge portion thereof engaged With said seating surface, a pair of vertically extending and laterally spaced flexible strands having winding connections at their upper ends on said shaft and operating connections at their lower ends with said valve plate along a diameter thereof parallel to said shaft, said strands being effective to el vate said valve plate axially out of engagement with said seating surface upon being wound on said shaft in response to rotation thereof, and means for engaging said plate at a point spaced from and for tilting it about said last-named diameter in response to continued upward movement thereof.

References Cited by the Examiner UNITED STATES PATENTS 754,547 3/1904 Desmond 137-630.14 1,710,585 4/1929 Matthessen 251-298 1,794,830 3/1931 Benger 137-630.15 X 1,995,052 3/1935 Bondenlos 137630.15 X 2,482,198 9/1949 Melichai 251-303 X 2,524,474 10/ 1950 Randel.

2,710,737 6/1955 Schaupp 251298 X 2,879,799 3/1959 Jansen 137630.15 X

3,136,338 6/1964 Hamel 137-630.14

FOREIGN PATENTS 1,303,602 10/1962 France.

CLARENCE R. GORDON, Primary Examiner,

Claims (1)

1. A VALVE COMPRISING A VALVE SEAT HAVING AN ANNULAR SEATING SURFACE FACING AXIALLY OUTWARDLY THEREFROM, A CIRCULAR VALVE PLATE ADAPTED TO OCCUPY A CLOSED POSITION WITH A PERIPHERAL EDGE PORTION THEREOF ENGAGED WITH SAID SEATING SURFACE, A PILOT VALVE MEANS ON SAID PLATE COMPRISING A CYLINDER HAVING ONE END SECURED TO SAID PLATE AND PROJECTING AXIALLY THEREFROM IN A DIRECTION OPPOSITE THAT IN WHICH SAID SEATING SURFACE FACES, SAID PLATE HAVING AN OPENING THEREIN ALIGNED WITH SAID CYLINDER, A LINER ABOUT THE INNER SURFACE OF SAID CYLINDER HAVING V-SHAPED NOTCHES THEREIN WITH THE SMALL ENDS OF SAID NOTCHES ARRANGED ADJACENT THE OTHER END OF SAID CYLINDER, AN ANNULAR PILOT VALVE SEAT AT THE SAID OTHER END OF SAID CYLINDER IN A POSITION SPACED AXIALLY BEYOND THE SAID SMALL ENDS OF SAID NOTCHES, AND A PILOT VALVE PLATE MOVABLE AXIALLY IN SAID CYLINDER AND ADAPTED TO OCCUPY A CLOSED POSITION AT THE SAID OTHER END OF SAID CYLINDER ENGAGED WITH SAID ANNULAR PILOT VALVE SEAT, AND VALVE OPERATING MEANS OPERABLE INITIALLY TO MOVE SAID PILOT VALVE PLATE AXIALLY TOWARD SAID CIRCULAR VALVE PLATE TO DISENGAGE IT FROM SAID ANNULAR VALVE SEAT AND OVER SAID NOTCHES TO PROVIDE RESTRICTED VALVE OPENINGS OF GRADUALLY INCREASING DIMENSIONS BETWEEN OPPOSITE SIDES OF SAID CIRCULAR VALVE PLATE, AND THEREAFTER TO MOVE SAID CIRCULAR VALVE PLATE AXIALLY TO MOVE IT OUT OF SEATING ENGAGEMENT WITH SAID ANNULAR SEATING SURFACE.

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