Abstract: A vacuum valve for die casing machine comprises a valve seat, a bottom die and a top die and a wavy lead-in runner between the bottom and top die. The bottom die has a vent hole and the top die has a feed-in inlet. The valve seat has an accommodating tank enclosing two gears, each gear engaged with one tooth rack. An induction rod is arranged on the tooth rack near the feed-in inlet and passing through an induction hole on the bottom die. A control rod is arranged on the tooth rack near the vent hole and passes through a valve hole on the bottom die. The control rod has a plurality of axial slots on one end thereof. The axial slots are initially exposed out of the valve hole and moved with the control rod to indent into the valve hole to seal the valve hole.

Abstract: Method of preventing contact of oxygen with a metal melt during continuous casting, the metal melt flows into a casting chamber bounded by rolls and a hood and leaves this chamber as a stream. To completely prevent contact of oxygen with the metal melt and thus reoxidation, oxygen attempting to enter via any gaps between the walls and/or adhering to the walls is removed by suction applied at a succession of suction stages at the periphery of each roll before a gap between the hood and the roll at the top of the casting chamber. Inert gas may then flow to the rolls near the gap.

Abstract: A process for die-casting aluminum and aluminum alloys is such that the molten metal is introduced into a filling chamber and injected from the filling chamber into a mold cavity by a piston. The mold cavity is evacuated in advance, after which it is flooded with oxygen. After flooding with oxygen and before injecting the molten metal into it, the mold cavity is again evacuated. Finally, the molten metal is injected into the hollow mold cavity. The process enables die-cast parts to be produced with low tendency to forming pores and blisters.

Abstract: A strip casting plant with a circulating belt. In the cooling area, the belt is sucked against carriers by a negative pressure in the cooler. The carriers are arranged so that, with given mechanical properties of the circulating belt, a deflection that compensates for the thermal elongation takes place between the supporting surfaces of the carriers.

Abstract: An apparatus and method for pressure casting a battery part wherein the state of molten lead is monitored so that when the molten lead enters a liquid-to-solid transformation stage, the volume of the mold available for the lead to solidify therein is quickly reduced through a volume contraction step to thereby cause the molten lead to flow into the remaining volume at the same time one maintains pressure on the molten lead. As the molten lead solidifies under the reduced volume and high pressure it produces a battery part that is substantially free of both tears and cracks. In an alternate method, the lead is allowed to solidify and at least a portion of the lead is mechanically deformed through a volume contraction step to cause cracks or tears in the battery part to be eliminated thereby providing a battery part free of cracks or tears.

Abstract: After a cavity 2 of a die-casting mold 1 is evacuated to exclude gases, oxygen gas is blown into the cavity 2 until an internal pressure of the cavity exceeds the atmospheric pressure, and then a molten metal 5 is forcibly injected into the cavity 2. The cavity 2 is evacuated to a degree of vacuum less than 100 millibar through a suction nozzle 11. The oxygen gas is blown through a nozzle 14 into the cavity 2 so as to fill the cavity 2 with the oxygen gas at an internal pressure higher than the atmospheric pressure. When the molten metal 5 is injected into the cavity 2 clarified in this way, inclusion of gases is perfectly prohibited. As a result, obtained die-cast products are free from defects such as blowholes or porosity caused by inclusion of gases and so useful as functional members as well as structural members.

Abstract: A vacuum die casting system has three die casting machines connected to a single vacuum system, all of which is controlled by a programmable logic controller. The controller allows any two of the machines to be operatively connected to the vacuum system so that the casting operation of those two machines are performed under vacuum. The controller comprises six address relays, a sixteen channel input card, a processor, a sixteen channel output card, an interface and two high speed counter cards. The result is an efficient, reliable, and economical vacuum die casting system.

Abstract: The apparatus includes a diecasting mold and evacuation elements for the controlled evacuation of a mold cavity. The evacuation elements includes a vacuum tank and a suction line interconnecting the vacuum tank and the diecasting mold. the suction line includes a first valve and a second valve which is coupled in parallel to the first valve. The valves are arranged so that a reference space is formed therebetween. The method for manufacturing die-castings includes evacuating a diecasting mold, filling the diecasting mold with casting material, removing the die-casting, forming a reference space in a portion of the suction line by closing the two valves which are coupled in parallel, measuring moisture, and pressure and temperature in the reference space, and controlling the apparatus in accordance with the measured values.

Abstract: A die casting vacuum valve system with mating vent blocks which include lands and grooves defining a serpentine path enabling overflow of molten material. The path restricts, stops and prevents further flow of the molten material in the case of an electrical or mechanical malfunction.

Abstract: A vacuum valve includes a first and second die block both adapted to be secured to a die of a die pair. A slot is in one of the die blocks in fluid communication with a mold cavity. A valve member is movable between a first position permitting fluid flow through the slot in a second position inhibiting fluid flow through the slot. A power operated actuator includes a reciprocal movable output member. A gear drive mechanism is coupled with the output member and with the valve for changing movement of the actuator into movement of the valve member. A controller controls the reciprocation of the actuating member.

Abstract: A valve for a vacuum die casting machine has a cover die block and an ejector die block. A slotted member and an abutting slotless member abutting the slotted member are movable between an open, fluid-passing position and a closed, fluid-blocking position. A controller directs movement of the valve between the open and closed positions. The valve is moved to its open position as the air within the cavity and associated lines is being evacuated and is moved to its closed position as the shot is injected into the die cavity. The slotted and slotless members may either be rotatable drums or elongated bars. The slotted drum includes a slotted end and an actuation end. Similarly, the slotted elongated bar includes a slotted end and an actuation end. Alignment of the slot of either the rotatable slotted drum or the movable slotted bar with the vacuum passage allows the passage of fluid.

Abstract: The delivery unit includes a transfer member in the form of a linear transfer plunger or slide that acts to transfer controlled amounts of lubricant from a loading chamber to a delivery chamber for delivery by air pressure to the casting apparatus. Various delivery units are included arranged in three groups having similar characteristics including a charge control mechanism and the form of the transfer plunger. Various arrangements of die casting apparatus with a lubricant delivery unit for delivering lubricant into selected locations of a die casting machine are also included.

Abstract: An expendable core is positioned in the molding cavity of a die casting die including hollow mounting pins affixed to the die which mate with recesses formed in the expendable core. Vacuum applied to the recesses through the hollow mounting pins anchors the core in the die cavity.

Abstract: The vacuum valve apparatus is used in die casting equipment of the type which utilize a source of vacuum pressure in an internal die cavity for making a casting. The apparatus includes a valve body that has components that are separable along a split line that is positioned to facilitate removal of casting material from internal ports that may result in the event of a malfunction.

Abstract: The apparatus is used in die casting equipment of the type which utilizes a source of vacuum pressure in an internal die cavity for making a casting. The apparatus includes a valve body that has components that are separable along a split line that is positioned to enable easy cleaning of casting material from internal ports. The apparatus has a valve, a trap operatively connected to the valve body and a closed chamber with an inlet thereto. The chamber is adapted to receive and contain casting material that may enter the inlet thereof.

Abstract: The apparatus has a generally cylindrically shaped rotating collar for sealing the chamber after casting material has been poured into it. The apparatus has a slidable plunger mechanism with an enlarged tip for forcing casting material through a shot sleeve toward the die. A flat annular collar retainer plate is located at right end of the collar. A sleeve seal tube is attached to the collar retainer plate adapted to receive the plunger tip. A seal housing is carried by and is slidable on the plunger stem, has an enlarged left end portion in which a sleeve seal is located so that when the plunger mechanism is moved to the left, the plunger tip enters the chamber and the seal housing and plunger stem move to the left until the seal engages the seal tube during leftward movement of the plunger. Further movement of the plunger stem results in the stem sliding relative to the seal housing while the plunger tip forces material in the chamber toward the die cavity.

Abstract: A method for producing composite materials by forming one material in a die cavity such that another material can be forced into the same die cavity and infiltrate the spaces in the first material. A method for producing a composite comprising the steps of injecting reinforcement material in a binder or suspension into a die cavity; burning off or removing the binder or suspension such that the reinforcement material remains in the die cavity; injecting liquid metal into the same die cavity such that it infiltrates the reinforcement material; solidifying the liquid metal; and removing the metal infiltrated composite material from the die cavity. An apparatus comprised of a die and a die cavity disposed inside the die. The apparatus is also comprised of a first port extending from the die cavity to the surface of the die through which reinforcement material in a binder is injected into a die cavity.

Abstract: A lifting and turning unit for a melting or casting plant. The lifting and turning unit for a deposit stand, preferably a table, for ingot molds of a vacuum melting and casting plant is provided. The unit consists of a tubular, vertically arranged lifter column that is axially movable with a hydraulic piston-cylinder unit and that has its upper end carrying the ingot mold table. A guide system composed of guide columns and of a yoke is provided. The guide columns serve for guiding the lifter column and for protecting the lifter column against twisting. The drive for the rotation of the rotatable ingot mold table is connected to the lifter column away from the harsh chamber environment. The unit provides an extremely low maintenance lifting and turing device wherein the longitudinal movements and the rotary movements can be executed separately from one another and thus allow for an exact positioning of the table.

Abstract: The pattern is surrounded by packed unbound molding medium within a container. The gaseous material resulting from the evaporation of the pattern is removed from within the container as the gaseous material permeates through the packed unbound molding medium. The outflow of the gaseous material is regulated to control the rate of displacement of the pattern by the molten metal. The removed gaseous material is cleaned and cooled, thereby forming condensate and detoxified gas. Thereafter the condensate, and detoxified gas are discharged.

Abstract: A vacuum chill device is provided for reducing porosity in a bore wall of a lost foam metal casting. In a preferred embodiment, the chill device is attached to a vaporizable pattern formed of polystyrene or the like and includes a vacuum chamber received in a bore defined by the pattern. The pattern and chill device are embedded in a body of unbonded sand particles or the like, whereupon the refractory body extends therebetween. The vacuum chamber is connected to a vacuum line that leads outside the mold and includes screened orificies through which the vacuum chamber communicates with the surrounding refractory body. During casting, pattern decomposition vapors venting into the bore are drawn through the orifices into the vacuum chamber and exhausted through the vacuum line. Removal of the hot vapors from the bore by the vacuum device accelerates solidification of the bore wall to reduce shrink porosity therein.

Abstract: A vertical injection apparatus for a die casting machine is disclosed. The setting is made such that a timing for vacuum evacuation applied to a portion into which air enters is suitably earlier than that for vacuum evacuation applied to a die cavity. Thus, this allows a solidification layer tightly formed on the end surface of a plunger tip to prevent air from entering into the die cavity, making it possible to desirably carry out injection and to remarkably improve quality of casting products. By improving the structure for holding a vacuum evacuating tube, this apparatus can facilitate repairing word required when the evacuating tube is clogged with hot molten metal.

Abstract: An automatic core setting machine having a movable mask with pockets for holding foundry cores until the mask is brought into face-to-face abutment with a mold, and a vacuum system comprising a body member integral with the pocketed mask and defining an interior suction chamber, the body member comprising a first wall having means defining a plurality of inlet ports terminating on the interior surface of the first wall in a plurality of injector nozzles, a second wall parallel to the first wall and having means defining a plurality of outlet ports terminating on the interior surface of the second wall in a plurality of ejector nozzles, each of the plurality of outlet ports being axially aligned with one of the plurality of inlet ports, and side walls rigidly connecting the first wall and the second wall and defining a space therebetween; means defining a suction opening through at least one of the side walls, the suction opening communicating with the interior suction chamber of the body member; means for con

Abstract: A lost foam sand casting system wherein patterns supported by holding rings in sand filled molds vaporize, when molten metal is poured into the molds and fills the voids created, to thereby form castings. The system includes an indexable turntable surrounded by a series of adjacent processing stations. The processing stations include a sand depositing and compacting mechanism for filling a mold in which a foam pattern has been placed, a pouring station with a ladle for pouring a measured volume of metal into each mold while a suction is applied to the bottom of the mold, cooling stations, and a mold emptying station. The turntable is supported for rotary travel by a series of floor mounted rollers and a hydraulic cylinder mechanism extends below the upper level of the rollers into engagement with pins depending at intervals from the turntable to index the turntable from station to station.

Abstract: An apparatus for producing a compound material such as a fiber reinforced metal comprises a first retaining chamber into which molten matrix metal e.g. aluminum etc. is introduced, a plunger for applying a pressure to the molten matrix metal positioned below the first retaining chamber, a second retaining chamber adapted to receive reinforcement materials e.g. fibrous ceramics called "whisker", the second retaining chamber being in vertical alignment with the first retaining chamber so as to communicate therewith, a clamping device positioned above the second retaining chamber and supported movably in a vertical direction, and heating means provided in the first and second retaining chambers. The apparatus thus configured makes it possible to easily impregnate the molten matrix metal into space between the reinforcement materials, thus producing a reinforced compound material with high quality.

Abstract: Lead or bismuth fumes emitted from steel during a strand casting operation are confined, collected and removed.

Abstract: A method of continuously casting a metal and an apparatus for continuously casting a metal wherein such a metal as copper, aluminum and so on is degassed continuously by means of at least two vacuum chambers which are installed over a preserving container for preserving a molten metal before being introduced to a mould and one of which pumps up the molten metal for degassing thereof while the other of which exhausts the molten metal after degassing thereof.

Abstract: An arc furnace and investment casting apparatus includes a copper base with an integrally formed crucible having a passage therethrough. A vacuum chamber is positioned on the top of the copper crucible with a non-consumable cathode projecting into the chamber to effect melting of metal placed in the crucible. A vacuum chamber is also suspended beneath the crucible for support of a mold to receive molten metal flowing through the passage.

Abstract: The present invention relates to a method and apparatus to be used in the reclamation of foundry sand. Mold flasks containing foundry sand shaped by a pattern to form a cavity into which molten metal has been poured are, after the metal has set, subjected to greatly reduced atmospheric pressure whereby to cause the moisture in the foundry sand to evaporate into water vapor, thereby removing moisture and heat from the sand so that the particles can be reused free of lumps or clumping of sand.

Abstract: A continuous casting assembly has a pair of contiguously counter-rotating belts for controllably forming a continuous cast metal ribbon. One of the belts is chilled and forms a casting surface for the cast ribbon, while the other belt is intimately positioned to hug the ribbon and improve the quality of the ribbon. The two belts are squeezed together to compress the ribbon by evacuating between the belts and allowing the atmospheric pressure to act on the opposite surfaces of the belts. A sealing box adjacent the lateral edges of the belts includes elongated floating seals and provides the evacuation by connection to a vacuum source. The floating seals are formed of plastic rods and are retained in the sealing box by end wiper seals which also serve to seal against the belts at the ends of the box.

Abstract: A melting and pressure casting device characterized in that it comprises a cylindrical electric heating means set in a closed chamber reducible and increasable in gas pressure, a vertically long crucible set in the heating means, a mold provided below the crucible and connected thereto, and an upper sprue communicating between the lower portion of the pouring cup and the sprue formed in the mold, wherein the melt for casting is held by its surface tension in the pouring cup and the melt thus held is poured under pressure by pressurizing the chamber into the mold through the upper sprue to thereby make a casting.

Abstract: A method and apparatus for continuously casting a filament within a region of preselected vacuum and passing the filament to ambient region of higher pressure include a rotating casting wheel which has an annular peripheral quench surface. A guide housing encloses the casting wheel to separate the wheel from the ambient region and to delimit a guide region which is adapted to pass the filament therethrough to an exit region communicating into the ambient region. An extrusion housing delimits an extrusion chamber which communicates with the guide housing and has a portion of the quench surface disposed therein. An extrusion mechanism located in the extrusion chamber extrudes molten metal onto the quench surface to form the filament, and an extrusion vacuum mechanism provides a preselected vacuum in the extrusion chamber. A fluid jet mechanism disposed in the guide housing reduces the pressure in the extrusion chamber and directs the filament through the guide region.

Abstract: A mask having pockets for holding foundry cores is swung downwardly and laterally from a core receiving position to a presetting position and then is lowered vertically to set the cores into the cavities of a sand mold. When the mask is in its receiving position, the top of the mask is tilted downwardly towards the mold and the pockets face outwardly to facilitate easy loading of the cores into the pockets without the application of vacuum. As the mask is swung downwardly and inwardly, it is turned to cause the pockets and cores to face downwardly (with the application of vacuum) preparatory to the cores being lowered vertically into the mold cavities.

Abstract: A casting machine die evacuation system has a vacuum source for evacuating the die cavity during casting connected to a chill block vent passage through a vacuum cut-off plug driven by a high pressure hydraulic system into an evacuation position at the start of casting and into a vacuum cut-off position in response to fast shot plunger operation. The tip of the plug is held in contact with the chill block so that cast material flow into the chill block vent passage will flow around the diameter of the plug without acting to unseat the plug from its vacuum cut-off position.

Abstract: An apparatus for rapidly quenching a metal or alloy in the molten state by projecting a jet thereof from a crucible 7 onto a cooled belt 1 moving at high speed inside a vacuum chamber 3. The crucible is mounted outside of and above the chamber, with its curved bottom, provided with a casting orifice 14, resting on the rim 5' of an opening provided in the upper cover 6 of the chamber.

Abstract: The invention provides an apparatus and method for continuously casting a filament, such as a glassy metal filament, at high speed within a zone of preselected vacuum. A continuous extrusion mechanism and a rapidly moving quench surface are located within a casting module. A vacuum mechanism provides the preselected vacuum in the module as the filament is cast, and a transport mechanism continuously moves the resultant rapidly advancing filament across the boundary between the vacuum in the casting airlock mechanism substantially preserves the module vacuum as the cast filament is transported across the boundary and a passivator mechanism passivates the quench surface to prevent the filament from adhering thereto.

Abstract: Apparatus for casting in a vacuum has a single evacuable furnace chamber 10 in which the charge melting and mould heating takes place. The charge is melted in a crucible 24 by an induction coil 20, while the mould is heated by resistance heaters 18 which are made from a FECRALLOY (Registered Trade Mark) material and can be operated in air or vacuum. In operation an empty mould 16 and a charged crucible 24 are positioned in the furnace 14 and the furnace chamber is sealed. The heaters 20 and 18 are operated while the furnace is pumped down. A control device 40 ensures that the charge is not melted until the appropriate vacuum level has been reached. After pouring the filled mould is withdrawn into a withdrawal zone 25 and as soon as the casting has solidified to the extent that air can be admitted to the chamber without detriment, the vacuum is released and the mould and charge replaced.

Abstract: A plant for continuously casting a metal, in particular steel, is provided comprising an open-ended mold. In order to provide an arrangement by which the hazards to the operators due to the emissions emerging from the mold are prevented, with an unobstructed view into the mold cavity being ensured, an emission collecting device covering the mold cavity and connected to an exhaust duct is provided above the mold at a distance therefrom to suck off the emissions emerging from the mold.

Abstract: A thin strip of metal or alloy is subjected to rapid solidification as it is ejected under pressure in a molten state from a crucible onto a cold, continuous band moving at high speed beneath the crucible's opening, in order to form metal strips in the vitreous state. An atmosphere under reduced pressure surrounding the zone of impact of the molten metal on the band is provided by a partially evacuated housing having opposed narrow inlet and outlet openings through which the band passes. The band is cooled and precisely positioned, and its vibration is minimized, by ejecting fluid from openings in the bottom of the housing, over which the band passes in closely parallel fashion. A pressurized gas at low temperature, ejected through these openings in the direction of the band, creates a fluid cushion between the band and the bottom of the housing.

Abstract: A casting apparatus wherein a weighted lever operated plunger has its operational rate regulated by a friction brake. A movable weight on the lever provides a selection of amplified operating force on the plunger. The lever is coupled with the piston of a vacuum pump having a valve to regulate the rate of application of vacuum to the molding flask. Safety linkages coupled to the lever prevent non-scheduled operation of the casting apparatus.

Abstract: An arrangement incorporated with a mold for use in a die casting machine or an injection mold machine comprising: a gas vent passage formed in the mold communicating with a cavity of the mold; two symmetrical by-pass passages branched from the gas vent passage; a gas discharge passage communicating with the outside of the mold; and valve means including a valve chamber formed in the mold having a valve located therein and communicating with the above-mentioned passages. The valve in a first position cooperates with the valve chamber to prevent the gas vent passage from communicating with the gas discharge passage, but prevents both the gas vent passage and the by-pass passages from communicating with the gas discharge passage when in a second position.

Abstract: A precision casting device especially suitable for dental use, which includes melting and casting chambers supported by a frame such that they are arranged coaxially up and down in the frame under a normal operating state and can be drawn horizontally out of the frame during service time in order to facilitate access to the interiors of them, and which is provided with evacuating apparatus and an inert gas supply and can carry out the casting process in which a casting material is molten in an inert atmosphere, the molten material is then supplied to a mold in a vacuum state and, therafter, casting is effected under a pressure of inert atmosphere.

Abstract: A vacuum apparatus comprises a frame which carries two vertical plates with a mobile plate mounted in guides therebetween. One die portion or part of a split die is rigidly fixed on the mobile plate by means of a die holder telescopically connected to a vacuum casting chamber housing rigidly mounted on a stationary plate which carries the other die portion or half of said die. Air-tight seals are provided at the housing joints and the housing is provided with viewing ports and with means for cleaning a die cavity.

Abstract: This invention relates to improvements in a liquid transferring device, in particular for molten metals, of the type comprising an inverted U-shaped siphon connected with a crucible to form a hydraulic circuit having one or more liquid inlet openings and connectable to at least one source of vacuum and at least one source of pneumatic pressure in order to suck the liquid into the crucible and then push the same through the hydraulic circuit and prime the siphon. The improvement comprises a degassing chamber located at the siphon bight and maintained under a pre-established negative pressure during the transferring operation.

Abstract: The invention relates to a process and apparatus for manufacturing silicon astings or moldings, having a columnar structure of single-crystal regions of crystal with a preferential crystallographic orientation, and which can be manufactured cheaply and in large numbers in a semi-continuous mode of production. Liquid silicon is cast in a casting station, under an inert gas and preferably under reduced pressure, preferably in graphite molds which are exposed to a temperature gradient of 200.degree. to 1,000.degree. C. After cooling, the silicon is withdrawn automatically via a transport chamber connected to the casting station into special cooling stations, while the casting station is reloaded with an empty mold for repeating the process. The silicon blocks which have preferably been produced by this procedure are use as basic material for inexpensive solar cells having efficiencies of more than 10%, after they have been sawn into individual small wafers and have been doped and lead-bonded.

Abstract: For supporting and cooling the reverse surfaces of belts in apparatus for continuously casting metal strip between such belts, means enclosing the reverse surface of a belt includes a multiplicity of guiding faces that are distributed closely both crosswise and lengthwise of the belt to define an intended belt path, and that have nozzle openings through which liquid coolant is projected against the belt, rapidly flowing out in a layer over the guiding face and being withdrawn at localities close to all of the guiding faces. The belt, which may be forced toward the faces to stabilize it in its desired path, thus rests on a layer of rapidly moving liquid coolant, which affords efficient heat removal and an essentially complete liquid bearing, such apparatus and procedure being also deemed applicable to cooling other surfaces.

Abstract: In apparatus for the continuous casting of metal in strip form between moving belts, belt support means comprising a multiplicity of elements that are distributed crosswise and lengthwise of a belt path area beside the mold space and are individually yieldable against a loading force, permit close belt stabilization to a selected path while yielding locally under excess outward force by the belt such as caused by solidified metal. Arrangement of belt support and cooling means along the mold space in successive sections each individually adjusted in respect to one or more of the conditions of belt path taper; degree of compliance, if any, in the retention of the belt against the support; and cooling action; are such that these features, as well as provision, if desired, of local yieldability, permit accommodation of the apparatus to various requirements of casting operation.

Abstract: A process for casting steel ingots, wherein the steel from a ladle is cast under vacuum through the lid of a container which can be evacuated, into a mould, and wherein covering powder or anti-piping compound, respectively, is evenly applied upon the surface of the molten steel in the mould while the vacuum is maintained.

Abstract: A method of producing a reduced-pressure-shaped mould in which at least in the region of a sprue runner of the mould to be formed and in regions where a shield material for the mould material is likely to be destroyed during introduction of the molten material to be moulded, the mould material partially or entirely comprises moulding sand mixed with substantially 0.5% to substantially 3.0% by weight of binder.

Abstract: Apparatus for molding, for example, a seamless brake drum female mold having a plurality of radially inwardly extending grooves and ridges. The apparatus includes a generally hollow one-piece distensible and flexible hollow male mold having an annular side wall having a plurality of radially extending projections and undercuts and includes an outer core box positioned around the flexible mold and defining an annular cavity with it. The apparatus further comprises a packing mandrel for supporting the hollow flexible mold while mold material is packed around it and a vacuum mandrel to be inserted within the flexible mold to cause the collapse of the flexible mold so that the molded article can be lifted off the flexible mold despite the radially extending projections.

Abstract: A vacuum control valving apparatus for a vacuum sealed molding apparatus. The control valving apparatus is located between a pair of mold members, one stacked upon the other, and a mating surface on a rail conveyor truck. The valving apparatus provides a controlled communication of a first vacuum source to an evacuation chamber on the mold members. The valving arrangement also effects a connection of the evacuation chambers on each of the mold members to a second vacuum source connection of the rail conveyor truck when the mold members are vertically stacked one on the other and in the appropriate location on the rail conveyor truck.