Abstract: An apparatus for moving a stream of molten metal comprising a pumping member, a housing at least partially enclosing the pumping member, a power device seated on a support, and a shaft connecting the power device and the pumping member. At least one post is disposed between the support and the housing. The post includes an elongated rod comprising a metal alloy surrounded by an outer sheath. An inner member may surround the rod and provide a molten metal resistant barrier. The rod includes a first end connected to the support and a second end secured to the housing. A similar design for a shaft is also provided.

Abstract: A container does not need a member such as a stoke and the like that are exposed to the molten metal therein, thus the necessity to replace the parts such as the stoke and the like can be eliminated. In addition, there is no structure like the stoke in the container, the operability for the preheating is improved thus the preheating can be performed effectively. In addition, since a flow passage is formed inside the lining with high heat conductivity, inner heat of the container is easily conducted to the flow passage. Thus, the decrease in temperature of the molten metal that flows inside the flow passage can be suppressed to the utmost.

Abstract: An apparatus for producing a thixotropic metallic melt by simultaneously controlledly cooling and stirring the melt to form solid particles of a first phase suspended in a residual liquid second phase. Vigorous stirring of the metallic melt results in the formation of degenerate dendritic particles having substantially spheroidal shapes. The metallic melt is stirred to rapidly and efficiently circulate the forming semi-solid slurry. Circulation of the forming semi-solid slurry results in a substantially uniform temperature throughout. Through precision stirring and cooling, a semi-solid slurry is formed having a first solid phase of about 70-80 wt. % suspended in a second liquid phase.

Abstract: A molten metal pump shaft coupling system for use in the coupling or connection of elongated shafts to other components and equipment, and for the disconnection thereof. A coupling with internal discontinuous threads may be coupled with an externally threaded shaft, with either continuous or discontinuous threads. Aspects of the invention include multiple external threads which may be pitched to accomplish a quicker and more efficient disconnect system. Furthermore, a shaft removal system is provided which provides two points of contact to assist in rotating a broken shaft end out of a coupling.

Abstract: Apparatus for transferring liquid metals from a collection container (9) to a receiving container (1), comprising: a receiving container in the form of a ladle (1) provided with a mouth (4) for the introduction of the metal, means (8) for transferring the liquid metal from a collection container (9) to the ladle (1), the means comprising a cover (7) which can engage the mouth (4) of the ladle (1) in a leak-tight manner and which has a first opening (14) with which a liquid-transfer duct (11) is associated and at least one second opening (16) with which means (17, 18) for generating a reduced pressure are associated, and handling means (20) arranged for moving the transfer means (8) between a position in which the cover (7) engages the mouth (4) of the ladle (1) and the transfer duct (11) is immersed in the collection container (9) and a position of disengagement from the mouth (4) of the ladle (1).

Abstract: An apparatus for transferring molten metal from a melting furnace to a casting furnace is provided. A sensing and control system for the transfer of molten metal from a transfer furnace to a casting furnace is also described. The combination of the transfer apparatus with the sensing and control system provides for the introduction of reduced oxide molten metal into a casting furnace.

Abstract: A molten metal pump system which generally provides a refractory connection joint for connecting a refractory pump post to a pump base, the pump post including a refractory post with a first end, the first end including an internal joint peg aperture; a refractory base with a post aperture configured to receive the first end of the refractory post, and with a peg aperture contiguous with the post aperture; and a joint peg with a first end and a second end, the joint peg including a retention shoulder, the joint peg configured to insert through the peg aperture in the refractory base with a retention bar or bolt inserted through an aperture in the joint peg of refractory post, and the retention shoulder engaging the refractory base.

Abstract: An apparatus for dispensing a molten material from a reservoir of molten material includes a dispensing chamber in communication with the reservoir and a first valve adapted to regulate communication of the dispensing chamber with the reservoir. A riser communicates with the dispensing chamber for dispensing the molten material, and a second valve is adapted to regulate communication of the riser with the dispensing chamber. Also disclosed is a method for reducing the inclusion of oxides in a casting of a molten metal.

Abstract: New melt furnace for casting, of the kind that have a loading nozzle that connects to a liquid metal storage tank and from where an outlet nozzle opens out in the feed runner of the casts, and where, between the liquid metal storage tank and the feed runner of the casts, there is an additional heating chamber by means of a thermal plasma torch and a retaining wall submerged at least partially in the liquid metal between the additional heating chamber and the feed runner of the casts. For application in metallurgic foundry.

Abstract: A pump for pumping molten metal includes a pump base comprised of non-metallic, heat resistant material. The pump base comprises an inlet opening, a wall that forms a pumping chamber, a passageway that communicates the inlet opening with the pumping chamber, and an outlet opening that communicates with the pumping chamber. A piston comprising non-metallic, heat resistant material is disposed in the pumping chamber. The wall comprises non-metallic, heat resistant material. A connecting member is fastened to the piston. A valve permits and restricts flow of molten metal in the pump base. An actuator is connected to the metal connecting member, the actuator being adapted for effecting reciprocal movement of the piston in the pumping chamber. The piston has a coefficient of thermal expansion and configuration effective to enable it to expand into contact with the wall during its reciprocal movement in the pumping chamber.

Abstract: A molten metal pump system which generally provides a refractory connection joint for connecting a refractory pump post to a pump base, the pump post including a refractory post with a first end, the first end including an internal joint peg aperture; a refractory base with a post aperture configured to receive the first end of the refractory post, and with a peg aperture contiguous with the post aperture; and a joint peg with a first end and a second end, the joint peg including a retention shoulder, the joint peg configured to insert through the peg aperture in the refractory base with a retention bar or bolt inserted through an aperture in the joint peg of refractory post, and the retention shoulder engaging the refractory base.

Abstract: This invention is related to galvanizing roll assemblies provided with self-aligning hydrodynamically lubricated roller-bearings used in equipment submerged in molten metal.

Abstract: A pump for pumping molten metal includes a pump base comprised of nonmetallic, heat resistant material. The pump base comprises an inlet opening, a wall that forms a pumping chamber, a passageway that communicates the inlet opening with the pumping chamber, and an outlet opening that communicates with the pumping chamber. A piston comprising non-metallic, heat resistant material is disposed in the pumping chamber. The wall comprises non-metallic, heat resistant material. A connecting member is fastened to the piston. A valve permits and restricts flow of molten metal in the pump base. An actuator is connected to the metal connecting member, the actuator being adapted for effecting reciprocal movement of the piston in the pumping chamber. The piston has a coefficient of thermal expansion and configuration effective to enable it to expand into contact with the wall during its reciprocal movement in the pumping chamber.

Abstract: A friction or sliding body includes at least two composite materials reinforced with fiber bundles and containing a ceramics matrix. A first composite material forms the outside of the sliding body as a friction layer and a second composite material forms a supporting body joined areally to the friction layer. The fiber bundle lengths of the friction layer are significantly shorter than the fiber bundle lengths of the supporting body. The fiber bundles of the friction layer have a clear alignment perpendicular to the surface. The surface of the friction layer is formed substantially only of small regions of free carbon with a diameter of at most 1.2 mm, and a total fraction of the area of free carbon on the surface is at most 35%. The surface has an extremely fine crack structure and the friction layer exhibits virtually no stresses in the vicinity of the surface. A process for producing a friction or sliding body and a brake disc or brake lining are also provided.

Abstract: Self-aligning bearings are used for supporting a roll in molten zinc or zinc/aluminum, to permit the roll's shaft to align with the bearing axis between the pair of holding arms supporting the roll, and a pump for delivering metal under pressure to the bearing surfaces interface force a hydrodynamic film to lubricate the bearing components.

Abstract: An apparatus for dispensing a molten material from a reservoir of molten material includes a dispensing chamber in communication with the reservoir and a first valve adapted to regulate communication of the dispensing chamber with the reservoir. A riser communicates with the dispensing chamber for dispensing the molten material, and a second valve is adapted to regulate communication of the riser with the dispensing chamber. Also disclosed is a method for reducing the inclusion of oxides in a casting of a molten metal.

Abstract: A die casting system includes a vessel defining a reservoir with a controlled heater and an agitator for maintaining the bath of semi-solid metal in a homogeneous isothermal state, a transfer system capable of transferring a known quantity of metal in its semi-solid state to a mold cavity in a die casting machine, the transfer system including a heated suction tube, a vacuum source for vacuum ladling semi-solid metal from the bath to a die, and a plunger tip providing a path for free air flow to allow evacuation of the suction tube during casting and a metal replacement system for replacing the known quantity of transferred metal with a similar amount of liquid metal so that a stable homogeneous isothermal bath of semi-solid metal is controllably maintained to be available for die casting operations.

Abstract: This invention relates to a casting machine furnace apparatus including a casting machine furnace, a supply furnace in fluid communication with the machine furnace and operative to supply a molten metal to the machine furnace, and a stopper module device disposed in a fluid path between the casting machine furnace and the supply furnace. The stopper module device includes a block housing and a stopper assembly. The block housing includes an inlet opening and an outlet opening, and is disposed in the fluid path. The stopper assembly is supported for movement relative to the inlet opening of the block housing between a working position, wherein the molten metal flows from the supply furnace to the casting machine furnace, and a non-working position, wherein the flow of molten metal is prevented.

Abstract: In a metallurgical vessel (1) having a tapping apparatus (5) for the slag-free withdrawal of liquid metal (3) from a molten metal bath (3) which is disposed in the vessel (1), a first leg (11) of a discharge duct (10) passes through the refractory vessel wall (15) and an overflow edge (14) in the connecting region of the two legs (11, 12) of the discharge duct (10) is higher than the upper edge (18) of the inlet opening (17) of the discharge duct. The molten metal (3) in the discharge duct is preferably inductively heatable.

Abstract: A method of dispensing or pouring molten metal, e.g., aluminum, from a container or vessel, the flow rate controlled to minimize splashing of the molten aluminum exiting the container, the method comprising the steps of providing a container for containing molten metal, the container having an outlet for dispensing molten metal therefrom and providing a body of molten aluminum in the container, the body having a top surface. A pressure lower than atmospheric pressure is maintained on the surface of the body in the container vessel for purposes of controlling the flow of molten metal through said outlet. Molten metal is dispensed through the outlet by increasing the pressure maintained in the container towards atmospheric pressure.

Abstract: A molten metal pump includes a base member submerged in the molten metal, a support member supported above the level of the molten metal by a post extending from the base member through a clearance bore in the support member and a coupling securing the post to the support member. The coupling is mounted to the support surface and includes gripping members operable to a locked position engaging the upper end of the post and to an unlocked position releasing the post. The coupling is aligned with the clearance bore in the support member to permit the post to be assembled or disassembled by axial movement through the clearance bore when the coupling is in the unlocked position.

Abstract: A method for reducing blow holes existing in a light alloy cast by using the hot isostatic process (HIP), comprising the steps of heating the light alloy cast at a temperature that is 5-100° C. lower than a temperature at which the liquid phase of the light alloy cast appears, and pressing the heated light alloy cast by a liquid pressure media, thereby reducing the blow holes existing in it.

Abstract: An apparatus for moving a stream of molten metal comprising a pumping member, a housing at least partially enclosing the pumping member, a power device seated on a support, and a shaft connecting the power device and the pumping member. At least one post is disposed between the support and the housing. The post includes an elongated rod comprising a metal alloy surrounded by an outer sheath. An inner member may surround the rod and provide a molten metal resistant barrier. The rod includes a first end connected to the support and a second end secured to the housing. A similar design for a shaft is also provided.

Abstract: A method of dispensing or pouring molten metal, e.g., aluminum, from a container or vessel, the flow rate controlled to minimize splashing of the molten aluminum exiting the container, the method comprising the steps of providing a container for containing molten metal, the container having an outlet for dispensing molten metal therefrom and providing a body of molten aluminum in the container, the body having a top surface. A pressure lower than atmospheric pressure is maintained on the surface of the body in the container vessel for purposes of controlling the flow of molten metal through said outlet. Molten metal is dispensed through the outlet by increasing the pressure maintained in the container towards atmospheric pressure.

Abstract: In a process for separating impurities from a raw gallium material containing impurities, a process for refining gallium comprising progressively solidifying a raw gallium material provided in a liquid state inside a vessel while applying stirring, such that the diameter of the tubular solidification boundary gradually advances from the inner wall plane of the vessel towards the center of the vessel to reduce the diameter of the tubular solidification boundary, and separating the liquid phase remaining in the central portion of the vessel from the solidified phase before the entire raw material inside the vessel is solidified. The process above is repeated as required by using, as the raw gallium material, the solidified phase from which the liquid phase is separated. A metallic gallium favorably used for the preparation of a compound semiconductor can be obtained by analyzing the impurity concentration of the impurity-concentrated Ga separated from the solidified layer.

Abstract: Disclosed is a molten metal submersible pump system which includes a unitized body which acts as its own jig during assembly to precisely align the motor mount framework, the pump body, the pump base, and the pump shaft. Further disclosed is such a pump system which provides greater than normal surface area and heat sink mass, which has resulted in an increased useful life of the pump system between required maintenance and replacement of parts.

Abstract: An apparatus for moving a stream of molten metal comprising a pumping member, a housing at least partially enclosing the pumping member, a power device seated on a support, a shaft connecting the power device and the pumping member. At least one post is disposed between the support and the housing. The post includes an elongated rod surrounded by a heat resistant outer member. The rod includes a first end connected to the support and a second end secured within a cavity in the housing.

Abstract: The melter furnace includes a heating chamber (16), a pump chamber (18), a degassing chamber (20), and a filter chamber (22). The pump chamber (18) is located adjacent the heating chamber (16) and houses a molten metal pump (30). The degassing chamber (20) is located adjacent and in fluid communication with the pump chamber (18), and houses a degassing mechanism (36). The filter chamber (22) is located adjacent and in fluid communication with the degassing chamber (20). The filter chamber (22) includes a molten metal filter (38). The melter furnace (12) is used to supply molten metal to an externally located holder furnace (14), which then recirculates molten metal back to the melter furnace (12).

Abstract: An apparatus for producing a thixotropic metallic melt by simultaneously controlledly cooling and stirring the melt to form solid particles of a first phase suspended in a residual liquid second phase. Vigorous stirring of the metallic melt results in the formation of degenerate dendritic particles having substantially spheroidal shapes. The metallic melt is stirred to rapidly and efficiently circulate the forming semi-solid slurry. Circulation of the forming semi-solid slurry results in a substantially uniform temperature throughout. Through precision stirring and cooling, a semi-solid slurry is formed having a first solid phase of about 70-80 wt. % suspended in a second liquid phase.

Abstract: A dosing chamber is insertable within and removable from the metal holding chamber of a molten metal furnace and is not formed as an integral part of the refractory lining of the molten metal furnace. The dosing chamber includes a chamber shell having a gas inlet port and a molten metal discharge port. The gas inlet port is functionally adapted to sealingly receive a gas stopper tube within the port. With a pressurized inert gas introduced through the gas stopper tube, molten metal contained within the dosing chamber is force out of the discharge port and up and into a metal receiver. The dosing chamber method and apparatus of the present invention is functionally adapted to be insertable within a variety of commercially available furnaces. The dosing chamber method and apparatus of the present invention may also be functionally adapted to be readily removable from the molten metal chamber such that the dosing chamber can be removed and cleaned as such is desired or required.

Abstract: Apparatus for pumping molten metal up a discharge pipe and into a casting mold or die cast shot sleeve and holding the metal at its highest point in the discharge pipe while replenishing the pumping chamber with molten metal for the next specific volume of molten metal to be pumped up the discharge pipe without allowing metal to flow backward in the discharge pipe at any time. The apparatus consists of a submerged pump vessel charged and discharged by a pump piston in the submerged vessel operated from above the level of the melt. A single stopper rod acts as the valve, operated from above the level of the melt to allow molten metal into a pumping chamber while at the same time holding the previous charge in the discharge pipe. Opening the stopper rod closes the inlet and allows the piston to force molten metal up the discharge pipe.

Abstract: SiC—C/C composite materials having a suitable kinetic coefficient of friction, good corrosion resistance in strongly oxidizing and corrosive environments, good creep resistance and spalling resistance, and high hardness. The materials are hardly oxidized or abraded even when exposed to high temperatures, while maintaining the excellent impact resistance and light weight of C/C composites. Molten metal pumps using the materials are provided from which components do not dissolve into the molten metal even when used in molten metal and have sufficient thermal impact resistance and oxidation resistance.

Abstract: An auger pump for pumping molten magnesium and its alloys from a furnace to a die casting machine, ingot mould, DC caster or the like is disclosed. The pump is comprised of a linearly aligned upper and lower portion. The upper portion is comprised of a housing which is attached to the furnace lid. An inverter duty electric motor is attached to the top of the housing and is controlled by a PLC. The auger shaft runs longitudinally between each portion and is supported in position by guide bearings located in the upper portion. The lower portion comprises a tubular casing which contains a gas inlet aperture and an feeder inlet aperture for drawing the molten magnesium into the pump. The outlet of the pump, a connector, is attached to a heated transfer tube, which conveys the molten magnesium to the mould.

Abstract: A melt withdrawal device for melt furnaces for charging casting machines has a melt conveying pump (1) comprised of a pump tube (2) forming a lower melt inlet (3) and an upper melt outlet (4) and of a pump shaft (5) extending inside the pump tube (2) and carrying a pump rotor (6). To achieve a melt conveyance which is largely independent of the melt level variations inside the melt furnace and can thus be dosed property, a charging means (7) for keeping constant the pump head (h) is provided before the melt conveying pump (1), which charging means (7) comprises a charging tank (8) accommodating the pump tube (2) with the melt inlet (3) and a charging pump (10) capable of filling the charging tank (8) with melt up to a melt overflow (9) determining the charging height, where the delivery rate of the charging pump (10) exceeds that of the conveying pump (1).

Abstract: The invention concerns a metering oven (1) with a vessel (12) for holding a liquid metal and with a device for detecting a liquid metal level in a vessel. A tubular probe (5) is connected to a gas source (10) for discharging a gas at a predetermined pressure from the gas source through the probe and out of its aperture. The probe is spatially associated in a fixed manner with the vessel such that pressures which can be detected by a pressure-measuring device (9) can be associated with different liquid metal levels inside the probe. At a given pressure threshold value, the pressure-measuring device can emit a signal for a given liquid metal level to be detected.

Abstract: An automatic molten metal injector is provided which has no rotary frictional parts and is thus durable. The injector has a furnace holding a molten metal to a predetermined level and having a first port. A fixed sleeve is provided in the furnace so as to be submerged in the molten metal and has a second port communicating with the first port. A slide sleeve having a side wall formed with a third port and a closed bottom wall is received in the fixed sleeve so as to be vertically slidable between a raised position in which the third port communicates with the second port, and a lowered position in which the third port communicates with the interior of the furnace. A piston is vertically slidably received in the slide sleeve. A drive unit individually or simultaneously raises and lowers the slide sleeve and the piston.

Abstract: Apparatus for dispensing a liquid material from a reservoir (12), the apparatus comprising a first vessel (11) which forms an intermediate chamber and which is arranged to receive material from the reservoir (12), a second vessel (10) which forms a dispensing chamber and which is arranged to receive material from the intermediate chamber (11), first pressurizing means whereby the intermediate chamber (11) can be pressurized, second pressuring means whereby the dispensing chamber (10) can be pressurized, first valve means (13) operable to permit material to be admitted into the intermediate chamber (11) from the reservoir (12), second valve means (14) operable to permit material to be admitted into the dispensing chamber (10) from the intermediate chamber (11) and a duct (19) extending from within the dispensing chamber (10) whereby material can be dispensed through the duct (19) from the dispensing chamber (10) by pressurization of the dispensing chamber (10)

Abstract: A gas jet-operated pump for removing dross from the surface of a bath of molten metal. The pump can be employed for delivering molten metal to the dross for diluting it or for removing it from a selected area.

Abstract: A two-chamber furnace for the low pressure countergravity casting of metal wherein the first chamber is a molten metal supply chamber connected by a submerged orifice closable by a stopper rod valve to a sealed second chamber that is pressurizable to fill a superjacent mold. The stopper rod valve is readily replaceable from the top of the furnace without having to empty the melt from the furnace.

Abstract: Metal strip close to its final dimensions is cast using a strip-casting apparatus provided with a melt-holding vessel and a conveyor belt, in which a metal melt, in particular steel, flows out of a casting nozzle of a closable pouring chamber which can be put under vacuum and is connected via a siphon to a main chamber which can be put under pressure. The casting nozzle is inclined by about 45.degree. and is of trumpet-like configuration in the region of the orifice on the inside of the nozzle wall remote from the main chamber. Additionally, a shut-off element which can be opened in a slit-shaped manner is provided near the orifice of the casting nozzle.

Abstract: The casting apparatus has a holding furnace for holding a reservoir of molten material, at least one smaller pumping furnace also for holding a reservoir of molten material and a casting cavity connected to the pumping furnace by one or more feed pipes. The pumping furnace is provided with a pressurizing assembly for applying a pressure to force the molten material from the pumping furnace into the casting cavity. The pumping furnace and holding furnace are contiguous and are connected by a non-return valve which prevents the flow of molten material from the pumping furnace to the holding furnace during pressurization but which allows the flow of molten material from the holding furnace to the pumping furnace after pressurization.

Abstract: The magnesium melting furnace (1) has a plurality of chambers. The material to be melted is fed into a melting chamber (2) through a charging chute (20), one end of which terminates under the surface of the melting bath. The melt is slowly transferred into a holding chamber (4) through a passage (3) situated in the lower third of a dividing wall (11) above a layer of impurities settling at the bottom (14) of the melting chamber (2). The melt slowly flows through the holding chamber (4), with impurities rising to the surface or settling on the bottom (15). The purified melt flows through a second passage (5) situated in the lower third of a second dividing wall (12) into a metering chamber (6). The melt can be removed from the metering chamber (6) through a transfer pipe (28) using a metering pump (27). The magnesium melting furnace (1) makes it possible to simultaneously melt, purify and remove the magnesium in metered quantities.

Abstract: By a method that may be used for transferring molten metal by using pressurized gas, molten metal in a metal furnace is automatically sucked into a molten metal chamber installed within the metal furnace through a fluid suction pipe by a balanced pressure inside the chamber. Then, when the molten metal sucked into the chamber is transferred to a specified position through a fluid feed pipe by applying a pressurized gas from an upper part of the chamber, the flow rate of the molten metal at the junction part between the fluid suction pipe and feed pipe or at the opposed part of an open end of the fluid suction pipe against that of the fluid feed pipe is accelerated, creating a higher flow rate at other parts of the fluid feed pipe. A molten metal transfer apparatus includes a molten metal chamber installed in a metal furnace and having a tightly closed upper part.

Abstract: A molten metal supply device capable of supplying molten metal with high precision to an injection sleeve of a die-casting machine, and capable of reducing molten metal leakage and damage to a molten metal conduit bridging between a holding furnace and the injection sleeve. The holding furnace is divided into a holding chamber and a supply chamber in fluid connection with the injection sleeve through the conduit. Both chambers can be selectively brought into and out of fluid connection by a stopper. First and second immersion bodies are immersibly provided to the chambers, respectively. The laser sensor detects a predetermined level of the molten metal. The first immersion body is immersed until the sensor detects the surface of the molten metal, whereupon the stopper blocks fluid communication between the chambers. By then lowering the second immersion body, molten metal is pushed out of the supply chamber and a predetermined amount of molten metal is supplied to the injection sleeve.

Abstract: An apparatus and method for tapping a reactor containing a molten fluid are disclosed. A conduit extending from the reactor is heated to a temperature which causes fluid extracted from the reactor to remain molten while in the conduit. Molten fluid is removed from the reactor by reducing the pressure in a receiving vessel attached to the conduit. As the pressure is reduced in the receiving vessel, molten fluid flows out of the reactor and into and through the conduit, discharging into the receiving vessel. The flow of molten fluid can be terminated by repressurizing the receiving vessel, thereby directing molten fluid in the conduit back into the reactor.

Abstract: In a pump for pumping molten metal including a motor and a shaft connected at an upper end to the motor and at a lower end to an impeller which is rotatable in a molten metal bath, the improvement being an apparatus for impeding oxidation of the shaft, including a gas source for releasing gas and a gas feed tube in fluid communication with the gas source, the gas feed tube being positioned to direct gas along the outer surface of the shaft.

Abstract: A constant molten metal surface level retaining furnace is integrally provided with a melting unit which permits a space for equipment to be reduced to efficiently carry out transfer of molten metal. This furnace comprises, a heating unit (16) for heating a casting material to produce the molten metal, a furnace body having a molten metal treatment and storage chamber (18) for storing a molten metal after having undergone a predetermined molten metal treatment, and a molten metal retaining chamber (20) for storing the molten metal to be delivered to casting machine, which is partitioned from the molten metal treatment and storage chamber (18). A molten metal surface level control means is provided for conducting a control so that a molten metal surface within the molten metal retaining chamber (20) is maintained at a predetermined level.

Abstract: A bubble-operated pump for recirculating molten metal in a bath of such metal.

Abstract: Depoling and aging of a piezoelectric transducers used at elevated temperatures is controlled by poling the transducer, applying a bias voltage in the same direction as the transducer is poled to maintain the piezoelectric transducer at an elevated potential, and applying a drive voltage having a lesser magnitude than the bias voltage to induce elastic strain in the transducer.

Abstract: A fabricated bubble operated pump for diluting dross in a steel treating bath.