Patent Description:
This disclosure relates generally to lead-acid battery manufacturing equipment, and more particularly to continuous lead strip casting lines, casters, and nozzles for battery plate grids.

Lead-acid batteries are a common energy storage device, and are often used in the automotive industry, marine industry, motive power industry, renewable energy industry, and uninterruptable power supply industry, as well as other applications. Among other components, lead-acid batteries include positive and negative plates that are installed in its interior and are made of lead or lead alloy grids with an electrochemically active battery paste material applied on the grids. The grids are commonly designed to have intersecting wires defining open spaces to receive the battery paste material.

Manufacturing grids for use as positive plates requires a certain amount of care, as the positive plates will ultimately include active material in the form of lead dioxide (PbO<NUM>) when charged and lead sulfate (PbSO<NUM>) when discharged. Unlike negative plates, the half-cell potential of the positive plates exists within a range where the positive plate grids can become oxidized during normal operation, which can result in corrosion on the grids and ultimate degradation of battery performance and even battery failure. As such, the positive plate grids are manufactured in specific processes that yield a grain structure resistant to corrosion. The positive plate grids are typically produced by gravity casting, which can be a slow and laborious process, or by a continuous casting and rolling process that involves a casting machine that turns molten lead into a hardened elongate continuous strip that is subsequently punched into individual grids connected together.

Conventional casting machines draw molten lead from an open pool that is exposed to one or more casting surfaces of one or more rollers. Lead impurities, along with dross that develops from the oxidation of alloy materials exposed to the atmosphere, residing at a top surface of the molten lead pool can be drawn into the cast strip during the process. The impurities can result in deformations and defects in the hardened strip of grids that are often magnified and intensified amid rolling. The deformations and defects, if present in the grid wires, can ultimately degrade battery performance and shorten the battery's useful life.

<CIT> relates to a lead strip caster for battery grids which includes a ladle, a nozzle and a pair of rollers, wherein the nozzle comprises passages communicating with the ladle outlet.

The present invention relates to a lead strip caster for battery plate grids, the caster being defined by claim <NUM>. Further embodiments are defined by dependent claims thereof. One embodiment of a lead strip caster for battery plate grids may include a ladle, a nozzle, a first roller, and a second roller. The ladle has an inlet to receive molten lead and an outlet. The nozzle has a passage that communicates with the outlet of the ladle in order to receive molten lead from the ladle. The first roller is situated at a first exterior side of the nozzle. The first roller may rotate via a first driver, and has a first outer surface. The second roller is situated at a second exterior side of the nozzle. The second roller may rotate via a second driver, and has a second outer surface. During use of the lead strip caster, molten lead exiting the passage of the nozzle comes into contact with the first outer surface of the first roller and comes into contact with the second outer surface of the second roller. The molten lead progressively hardens as it moves downstream of the passage.

One embodiment of a lead strip caster nozzle includes a first passage receiving molten lead, a second passage receiving molten lead, a first exterior working surface, and a second exterior working surface. The first exterior working surface may confront a first roller outer surface. The second exterior working surface may confront a second roller outer surface. During use of the lead strip caster nozzle, molten lead exiting the first passage may be delivered to the first exterior working surface, and molten lead exiting the second passage may be delivered to the second exterior working surface.

One embodiment of a lead strip caster for battery plate grids includes a nozzle, a first roller, and a second roller. The nozzle may have a first passage, a second passage, a first exterior working surface, and a second exterior working surface. The first roller may have a first outer surface that confronts the first exterior working surface in assembly. The second roller may have a second outer surface that confronts the second exterior working surface in assembly. During use of the lead strip caster, molten lead exiting the first passage is delivered to the first exterior working surface and comes into contact with the first outer surface, and molten lead exiting the second passage is delivered to the second exterior working surface and comes into contact with the second outer surface.

One embodiment of a lead strip caster for battery grid plates includes a molten lead delivery system, a nozzle, a first roller and a second roller. The molten lead delivery system includes a pump for supplying molten lead to a shoe supplying molten lead to a nozzle. A molten lead flow straightener may be disposed between the shoe and the nozzle. The nozzle may have one or more passages that communicate with the shoe to receive molten lead and supply it to first and second rollers adjacent opposite exterior sides of the nozzle and with outer surfaces which may come into contact with molten lead exiting the nozzle which lead progressively hardens as it moves downstream of the nozzle during operation of the lead strip caster. The nozzle may include first and second passages each receiving molten lead from the shoe and discharging it between and into contact with outer surfaces of the first and second rollers which lead progressively hardens into a solid strip of lead as it moves downstream of the nozzle.

Objects, features, and advantages of the present disclosure will be apparent from the following detailed description of exemplary embodiments and best mode, appended claims, and accompanying drawings in which:.

Referring in more detail to the drawings, a lead strip caster <NUM> is designed and constructed to produce a continuous lead strip more effectively and more efficiently than previously possible. The continuous lead strip produced by the lead strip caster <NUM> is intended for use as battery positive plate grids and can be subsequently punched and processed therefor. Among many potential advancements, the lead strip caster <NUM> possesses a smaller overall machine footprint to satisfy floor space demands; impurities and dross residing in molten lead pools are precluded from making their way into the produced lead strip; molten lead flow and movement is more effectively controlled as it travels through the lead strip caster <NUM>; and adjustments to strip width and strip thickness are more readily made. The lead strip caster <NUM> can be used in larger processes that manufacture lead-acid batteries for cars, trucks, hybrid vehicles, motorcycles, boats, snowmobiles, golf carts, consumer equipment such as powered wheelchairs, industrial equipment such as forklifts and robots, and for other applications. As an aside, and as used herein, the term downstream generally refers to a direction that is with the flow of molten lead as it moves through the lead strip caster <NUM>, the term upstream generally refers to a direction that is against the flow of molten lead as it moves through the lead strip caster <NUM>, the terms horizontal and vertical are used with general reference to the ground surface upon which the lead strip caster <NUM> is stationed for operation, and the term lead refers to both lead and lead alloy materials.

In general, the lead strip caster <NUM> is but one piece of equipment employed in a larger process to produce continuous lead strips. Referring to <FIG>, a continuous lead strip casting production line <NUM> can also be equipped with furnaces <NUM>, a set of rolling mills <NUM>, an edge trim cutter <NUM>, a tensioner <NUM>, and a reeler <NUM>, as well as other components. The continuous lead strip casting production line <NUM> of <FIG> is but one embodiment, and other embodiments of continuous lead strip casting production lines could include more, less, and/or different equipment than depicted and described. Additional processes downstream of the continuous lead strip casting production line <NUM> may include punching, pasting, cutting, drying, curing, and/or forming.

The lead strip caster <NUM> receives molten lead fed from the furnaces <NUM>, and transforms the molten lead into a hardened continuous lead strip that is advanced to the set of rolling mills <NUM> for further processing. At this stage in the process, the continuous lead strip has yet to be imparted with intersecting wires and open spaces. The lead strip caster <NUM> can have various designs, constructions, and components in different embodiments depending upon-among other considerations-the desired size of the produced continuous lead strip, the desired run rate of the continuous lead strip through the continuous lead strip casting production line <NUM>, and preceding and subsequent steps in the larger production process. In the embodiment depicted in <FIG>, the lead strip caster <NUM> includes a frame <NUM>, a ladle <NUM>, a nozzle <NUM>, a first roller <NUM>, a second roller <NUM>, a first driver <NUM>, and a second driver <NUM>. The frame <NUM> provides a structural skeleton for the lead strip caster <NUM> and supports other components of the lead strip caster <NUM>. The frame <NUM> can be made up of many vertical, side, and cross members of steel that are joined together.

Referring to <FIG>, the ladle <NUM> receives molten lead fed supplied to it from the furnaces <NUM>, and provisionally holds the molten lead in a pool A as the molten lead continues on to the nozzle <NUM>. With respect to the flow and movement of the molten lead, the ladle <NUM> is configured upstream of the nozzle <NUM>. The ladle <NUM> can have various designs, constructions, and components in different embodiments. In the embodiment presented in <FIG>, the ladle <NUM> is constructed of four side walls <NUM> and a bottom wall <NUM> that together define an interior <NUM> to contain molten lead. The ladle <NUM> has an open top <NUM> and a closed bottom <NUM>. The ladle <NUM> can, though need not, include a partition wall <NUM> located within the interior <NUM> and spanning from one side wall <NUM> across to another side wall <NUM>, thereby dividing the interior <NUM> into a first interior compartment <NUM> and a second interior compartment <NUM>. As molten lead makes its way through the interior <NUM> from the first interior compartment <NUM>, over the partition wall <NUM>, and to the second interior compartment <NUM> along a path B, degasification of the molten lead may occur. In this way, the partition wall <NUM> serves to retard the movement of the molten lead as the molten lead proceeds through the ladle <NUM>. An inlet <NUM> of the ladle <NUM> serves as the entrance through which molten lead enters the interior <NUM> from the furnaces <NUM>. The inlet <NUM> is located at a bottom section and bottom half of the ladle <NUM> and just above the bottom wall <NUM>, as shown best in <FIG>. Its location feeds molten lead from the inlet <NUM> directly to the first interior compartment <NUM>. Furthermore, an outlet <NUM> of the ladle <NUM> serves as the exit through which molten lead leaves the interior <NUM> to the nozzle <NUM>. Like the inlet <NUM>, the outlet <NUM> is located at the bottom section and bottom half of the ladle <NUM> and just above the bottom wall <NUM>, as shown in <FIG>. Its location receives molten lead directly from the second interior compartment <NUM>. As illustrated in <FIG> and <FIG>, the outlet <NUM> has a slot-like shape in order to accommodate and match a corresponding entrance of the nozzle <NUM>.

Referring to <FIG>, the nozzle <NUM> receives molten lead from the ladle <NUM> and controls the flow and movement of the molten lead for downstream delivery to the first and second rollers <NUM>, <NUM>. With respect to the flow and movement of the molten lead, the nozzle <NUM> is configured downstream of the ladle <NUM>. The nozzle <NUM> can have various designs, constructions, and components in different embodiments. In the embodiment presented in <FIG>, the nozzle <NUM> is made up of two-piece body halves with a first body segment <NUM> and a second body segment <NUM> that are bolted together in assembly, though the nozzle <NUM> could be made of a single one-piece construction in other embodiments. For the flow and movement of molten lead through its body, the nozzle <NUM> has a first passage <NUM> and a second passage <NUM> in this embodiment; still, in other embodiments the nozzle could have other quantities of passages such as a single passage. The exact quantity of passages and their design can be dictated by the desired thickness of the continuous lead strip departing the first and second rollers <NUM>, <NUM>, and the desired flow rate of molten lead passing through the lead strip caster <NUM>. For instance, in this embodiment, it was found through computational fluid analysis and experimentation that a pair passages promoted and facilitated improved molten lead fluid flow behavior compared to a single passage. Without wishing to be confined to a particular theory of causation, it is believed that the greater reduction in thickness observed in the single passage tended to cause an undesirable degree of irregular molten fluid flow behavior, or turbulence, within the single passage, which consequently hindered the flow of molten lead therethrough.

The first passage <NUM> is defined by inside surfaces of the nozzle's body and extends through the body from a first entrance <NUM> to a first exit <NUM>. Likewise, the second passage <NUM> is defined by inside surfaces of the nozzle's body and extends through the body from a second entrance <NUM> to a second exit <NUM>. The first and second passages <NUM>, <NUM> extend transversely across the nozzle <NUM> between a first side wall <NUM> and a second side wall <NUM>, and short of the overall transverse length of the nozzle <NUM>-the transverse length of the passages <NUM>, <NUM> equates to the width of the produced continuous lead strip. The first and second entrances <NUM>, <NUM> reside at an entrance end <NUM> of the nozzle <NUM> that can be mounted with the ladle <NUM> adjacent the outlet <NUM> so that the first and second entrances <NUM>, <NUM> fluidly communicate with the outlet <NUM> and receive molten lead therefrom. The first and second entrances <NUM>, <NUM> can have slot-like shapes to match the shape of the outlet <NUM>. Still, in other embodiments the first and second passages <NUM>, <NUM> can share a common entrance in the nozzle <NUM> that branches off downstream into separate passages. At the first exit <NUM>, the first passage <NUM> terminates openly to a first working surface <NUM> (subsequently described) and delivers molten lead thereto. Similarly, at the second exit <NUM>, the second passage <NUM> terminates openly to a second working surface <NUM> (subsequently described) and delivers molten lead thereto. In other embodiments not depicted in the figures, the first and second exits <NUM>, <NUM> need not necessarily terminate directly and immediately at the respective first and second working surfaces <NUM>, <NUM>, and instead could terminate openly to other locations of the nozzle such as at a location upstream of the respective working surface.

With the exception of the site of flow straighteners (subsequently described) in some embodiments, the first and second passages <NUM>, <NUM> can possess a uniform and constant size and dimension from their entrances <NUM>, <NUM> and to their exits <NUM>, <NUM>. Further, the first and second passages <NUM>, <NUM> can have the same size and dimension relative to each other. The first and second passages <NUM>, <NUM> can be designed to follow a route through the nozzle <NUM> that promotes and facilitates laminar fluid flow therethrough, and subdues turbulent fluid flow. For example, and referring particularly to <FIG> and <FIG>, in this embodiment the first and second passages <NUM>, <NUM> have routes that mirror each other and initially exhibit a first linear and parallel section C, then exhibit a divergent section D, and lastly exhibit a second linear and parallel section E. The first linear and parallel section C begins at the entrances <NUM>, <NUM> and spans straight therefrom with the first and second passages <NUM>, <NUM> remaining parallel with each other until the divergent section D. At the divergent section D, the first and second passages <NUM>, <NUM> take a sweeping and curved route, and deviate outboard away from each other. And at the second linear and parallel section E, the first and second passages <NUM>, <NUM> span straight to the exits <NUM>, <NUM> and remain parallel with each other throughout. Still, in other embodiments the first and second passages <NUM>, <NUM> could follow routes different than those presented here, and still effectuate suitable fluid flow.

As mentioned, in some embodiments the nozzle <NUM> may include flow straighteners to promote and facilitate laminar fluid flow through the nozzle <NUM> and subdue turbulent fluid flow. The flow straighteners can have various designs, constructions, quantities, and locations in different embodiments. In the embodiment presented in <FIG> and <FIG>, a first flow straightener <NUM> is disposed in the first passage <NUM>, and a second flow straightener <NUM> is disposed in the second passage <NUM>. To accept the flow and movement of molten lead therethrough, the first flow straightener <NUM> is located downstream of the first entrance <NUM> and upstream of the first exit <NUM>, and at the second linear and parallel section E; other locations are possible. The first flow straightener <NUM> spans across the full transverse length of the first passage <NUM>. At its location, the first passage <NUM> can have an increased size and dimension compared to its remaining extent in order to accommodate placement of the first flow straightener <NUM>. Likewise, to accept the flow and movement of molten lead therethrough, the second flow straightener <NUM> is located downstream of the second entrance <NUM> and upstream of the second exit <NUM>, and at the second linear and parallel section E; other locations are possible. The second flow straightener <NUM> spans across the full transverse length of the second passage <NUM>. At its location, the second passage <NUM> can have an increased size and dimension compared to its remaining extent in order to accommodate placement of the second flow straightener <NUM>. The first and second flow straightener <NUM>, <NUM> can be of different types. Referring particularly to <FIG>, in this example the flow straighteners <NUM>, <NUM> are of the honeycomb type with multiple ducts <NUM> through which molten lead flows.

To manage the temperature of molten lead flowing and moving through the nozzle <NUM> as the molten lead makes its way from entrance to exit, in some embodiments the nozzle <NUM> may include heaters. The heaters can have various designs, constructions, quantities, and locations in different embodiments. In the embodiment presented in <FIG>, a total of eight heaters <NUM> are carried internally in the nozzle's body. The heaters <NUM> can be positioned relative to the first and second passages <NUM>, <NUM> in order to generate more heat in the nozzle's body and to the molten lead more immediately downstream of the entrances <NUM>, <NUM>, as compared to the heat generated more immediately upstream of the exits <NUM>, <NUM>. The molten lead can hence experience a gradual reduction in temperature from its entrance in the passages <NUM>, <NUM> to its travel to the exits <NUM>, <NUM>. The heaters <NUM> can be of different types. In one example the heaters <NUM> can be cartridge-type heaters. Furthermore, it has been found that having the pair of passages <NUM>, <NUM> in some cases can aid the temperature management capabilities and effectiveness of molten lead compared to a single passage; the pair of passages presents reduced volumes and amounts of molten lead than a single passage, making it easier to impart heat thereto as desired.

Referring now particularly to <FIG> and <FIG>, at the exterior of the nozzle <NUM> and downstream of the passage exits <NUM>, <NUM>, the nozzle <NUM> has the first working surface <NUM> and the second working surface <NUM>. During use of the lead strip caster <NUM>, the first working surface <NUM> receives delivery of molten lead from the first passage <NUM> at the first exit <NUM>, and the second working surface <NUM> receives delivery of molten lead from the second passage <NUM> at the second exit <NUM>. The molten lead flows and moves downstream of the first and second exits <NUM>, <NUM> and along the first and second working surfaces <NUM>, <NUM> and to an egress end <NUM>, where the two streams of molten lead merge together and unite between the first and second rollers <NUM>, <NUM>. In this embodiment, the first and second working surfaces <NUM>, <NUM> resemble concave depressions defined by arcuately-shaped surfaces. The working surfaces <NUM>, <NUM> are shaped complementary to outer surfaces of the roller <NUM>, <NUM> so that the first roller <NUM> can nest in the first working surface <NUM> with a clearance maintained therebetween to accept delivery of molten lead, and so that the second roller <NUM> can nest in the second working surface <NUM> with a clearance maintained therebetween to accept delivery of molten lead. One example of the nesting between the rollers <NUM>, <NUM> and the working surfaces <NUM>, <NUM> of the nozzle <NUM> is illustrated in <FIG>. Similar to the passages <NUM>, <NUM>, the working surfaces <NUM>, <NUM> span transversely across the nozzle <NUM> between the first and second side walls <NUM>, <NUM>, where the side walls <NUM>, <NUM> serve to enclose the transverse extent of the molten lead thereat. Following their arcuate shape, the working surfaces <NUM>, <NUM> span from respective exits <NUM>, <NUM> to the egress end <NUM>, and therealong the working surfaces <NUM>, <NUM> confront the respective outer surfaces of the rollers <NUM>, <NUM> across the respective clearances. The extent of the confrontation and the extent of the maintained clearances provides an expansive scope of contact between the molten lead and rollers <NUM>, <NUM> compared to previously-known casting machines. The molten lead is hence more progressively cooled and hardened as it moves from the exits <NUM>, <NUM> and to the egress end <NUM> and downstream thereof.

The nozzle <NUM> is designed and constructed as a separate and modular unit in the lead strip caster <NUM> that can be readily assembled and disassembled in the lead strip caster <NUM>. In this way, the lead strip caster <NUM> can be equipped with an interchangeable nozzle component. Different nozzles of different designs and constructions can be exchanged in the lead strip caster <NUM> to produce continuous lead strips of various widths and thicknesses, as desired. For instance, the width of the produced continuous lead strip can vary among different nozzle designs and constructions with different transverse lengths between the first and second side walls <NUM>, <NUM>. In addition, the thickness of the produced continuous lead strip can vary among different nozzle designs and constructions via one or more of the following measures: adjustment of the sizes and dimensions of the passages <NUM>, <NUM>; adjustment of the sizes and dimensions of the clearances between the working surfaces <NUM>, <NUM> and outer surfaces of the rollers <NUM>, <NUM>; displacement of the forward and rearward location of the egress end <NUM>; and/or adjustment of clearance between the outer surfaces of the rollers <NUM>, <NUM>.

Together with the nozzle <NUM>, the first and second rollers <NUM>, <NUM> work to bring the molten lead from its molten state to a hardened state ready for further processing by the rolling mills <NUM>. Referring generally to <FIG> and <FIG>, as described, when assembled in the lead strip caster <NUM> the first roller <NUM> is situated at a first exterior side of the nozzle <NUM> where an arcuate section of a first outer surface <NUM> confronts the first working surface <NUM>, and the second roller <NUM> is situated at a second exterior side of the nozzle <NUM> where an arcuate section of a second outer surface <NUM> confronts the second working surface <NUM>. The first and second rollers <NUM>, <NUM> can have various designs and constructions in different embodiments. As depicted in <FIG>, in this embodiment the rollers <NUM>, <NUM> may have one or more grooves <NUM> at their outer surfaces <NUM>, <NUM> in order to augment traction established between the molten and hardened lead and the rollers <NUM>, <NUM>. At their axially outboard ends, the rollers <NUM>, <NUM> have first and second axles <NUM>, <NUM> for coupling to the respective first and second drivers <NUM>, <NUM> and permitting rotation thereabout. The first and second drivers <NUM>, <NUM> can be motors that drive continuous rotation of the respective first and second rollers <NUM>, <NUM> amid operation of the lead strip caster <NUM>. Lastly, and as partially depicted in the sectioned view of <FIG>, the rollers <NUM>, <NUM> can be equipped with a thermal construction <NUM> that circulates thermal fluid to manage and control the temperature of the outer surfaces <NUM>, <NUM>, as desired. In <FIG>, thermal fluid circulates through circulation veins that are represented and illustrated in the figure as vertical bars that lack sectional pattern lines. In one embodiment, the thermal construction <NUM> recirculates thermal fluid in the form of coolant, such as water, through internal chambers defined within the rollers <NUM>, <NUM>. The outer surfaces <NUM>, <NUM> are thereby cooled. In another embodiment, the thermal construction <NUM> recirculates heated thermal fluid through the internal chambers. The outer surfaces <NUM>, <NUM> are thereby heated. During use of the lead strip caster <NUM>, the streams of molten lead leaving the exits <NUM>, <NUM> come into direct contact with the respective cooled or heated outer surfaces <NUM>, <NUM> as the rollers <NUM>, <NUM> rotate. The streams of molten lead maintain that contact until after the streams merge and unite together downstream of the egress end <NUM>. The contact with the outer surfaces <NUM>, <NUM> serves to control the temperature of the molten lead, as desired, such as progressively cooling it into a hardened state. In this way, the rollers <NUM>, <NUM> and their thermal constructions <NUM> can serve to help control the temperature of the molten lead.

As described, the lead strip caster <NUM> is designed and constructed to exhibit a horizontal orientation. In other words, the ladle <NUM> and nozzle <NUM> are configured generally side-by-side relative to each other whereby molten lead flows and moves along a general horizontal and lateral course from the ladle's inlet <NUM> and ultimately to the nozzle's egress end <NUM>. While the flow and movement of the molten lead may have localized departures from a strictly horizontal and lateral course-such as when the molten lead passes over the partition wall <NUM> along the path B-the general flow and movement is still principally horizontal and lateral, especially when contrasted with conventional casting machines that have a vertical configuration. In the vertical configurations, molten lead is fed vertically downward from an upwardly-located ladle to a downwardly-located set of rollers. Impurities and dross residing at top surfaces of molten lead pools in the ladles of vertical configurations can make their way to the sets of rollers, which causes deformations and defects in the produced lead strip and ultimately in the grids. The horizontal orientation of the lead strip caster <NUM> and the nozzle <NUM> resolves these issues. Any impurities and dross residing at the top surface of the pool A remain thereat and are precluded from making their way to the nozzle <NUM> and, therefore, to the produced continuous lead strip. The ladle's outlet <NUM> is located at the bottom section of the ladle <NUM> and is directed horizontally and laterally to the nozzle <NUM>, as perhaps demonstrated best in <FIG>. This location and direction frustrates, if not altogether precludes, the migration of lead impurities and dross to the nozzle <NUM>. Furthermore, the flow and movement of molten lead through the nozzle <NUM> shields and safeguards the molten lead from the atmosphere, hence averting dross formation at the nozzle <NUM>.

As shown in <FIG>, a delivery system <NUM> may provide molten lead from a furnace directly to the nozzle <NUM> of the lead strip caster <NUM> without exposing the molten lead to the atmosphere to at least substantially preclude migration of lead impurities and dross to the nozzle. The supply system <NUM> includes a molten lead pump assembly <NUM> which in operation supplies molten lead to the nozzle <NUM> through a shoe <NUM> and desirably through a fluid flow straightener <NUM> received between the shoe and the nozzle. The pump assembly <NUM> may be have a centrifugal pump <NUM> with an inlet <NUM> and an outlet <NUM> submergible in a pool of molten lead in a pot of a lead melting furnace <NUM> or in a holding well (not shown) of molten lead transferred from a furnace <NUM>. The pump <NUM> may be driven by an electric motor through a shaft connected to an impeller with the shaft desirably received in a ceramic sleeve <NUM>. Desirably the pump inlet <NUM> may be positioned in the range of about one quarter to three quarters of the vertical height or extent of the pool of molten lead in the furnace pot or holding well. Typically, the pump assembly may deliver liquid lead to the inlet <NUM> of the shoe <NUM> at a pressure in the range of <NUM> to <NUM> MPa (<NUM> to <NUM> psi) gauge and at a flow rate of <NUM> to <NUM> (<NUM> to <NUM> lbs). of molten lead per minute. A suitable molten liquid lead transfer pump assembly is commercially available from Wirtz Manufacturing Company of Port Huron, Michigan, USA. A suitable transfer pump assembly is also disclosed in <CIT>. In use the pump assembly <NUM> supplies an excess quantity of liquid lead to an inlet <NUM> (<FIG>) of the shoe <NUM> through a conduit <NUM> and excess liquid lead is returned from an outlet <NUM> of the shoe through a conduit <NUM> to the furnace pot or holding well. If needed, these conduits may be thermally insulated and if needed equipped with heaters such as electric heaters to ensure that in use the lead remains in a liquid state as it flows through the conduits.

As shown in <FIG> the shoe <NUM> has a body <NUM> which may be generally rectangular, a longitudinally extending lead outlet slot <NUM> opening into a front face <NUM> of the body and communicating at generally opposed ends with inlet and outlet connectors <NUM>,<NUM> through inlet and outlet passages <NUM>,<NUM> in the body. To maintain lead in the shoe in a liquid state, electric cartridge or rod heaters may be received in bores or passages <NUM> extending longitudinally through the body, laterally spaced from each other and in heat transfer relationship with the lead outlet slot and its associated inlet and outlet passages. These heater elements may be thermostatically controlled to maintain the liquid lead in the shoe at a desired temperature range such as about <NUM> to <NUM> degrees Fahrenheit. In assembly the outlet slot of the shoe communicates with the nozzle <NUM> flow passages <NUM> and <NUM> at their entrances or inlets <NUM> and <NUM>, desirably through the fluid flow straightener <NUM>.

As shown in <FIG> desirably the flow straightener <NUM> may be in the form of a generally rectangular body <NUM> with a plurality of spaced apart and generally parallel passages or bores <NUM> extending therethrough. These passages may be arranged in a generally honeycomb pattern with alternating transverse rows of an odd and even number of generally parallel spaced apart passages such as <NUM> and <NUM> passages respectively. Collectively, the passages <NUM> may desirably correspond with the longitudinal extent and transverse width of the opening of the lead outlet slot <NUM> through the front face <NUM> of the shoe. As shown in <FIG>, typically each passage <NUM> has a diameter in the range of about <NUM> to <NUM> of an inch. <NUM> inch = <NUM>. Desirably the longitudinal and transverse extent of the outlet slot of the shoe and collectively the passages of the flow straightener may correspond with and span the perimeter of the combined entrances <NUM> and <NUM> of the passages <NUM> and <NUM> of the nozzle <NUM>.

In assembly the shoe <NUM> and the fluid flow straightener <NUM> desirably have a sealing gasket <NUM> between them, and may be aligned with and attached to the entrance end <NUM> of the nozzle <NUM> by suitable fasteners such as cap screws, bolts, or the like.

In use the pump assembly <NUM> supplies an excess quantity of molten lead under pressure to the inlet <NUM> of the shoe <NUM> and some of this liquid lead flows through the flow straightener <NUM> and into and through the nozzle passages <NUM> and <NUM> and into contact with the corotating rollers <NUM> and <NUM> upstream of the nip thereof to produce a cooled and hardened or solid state continuous solid lead strip which downstream of the rollers may be further processed by the rolling mills <NUM>, trimmer <NUM>, etc..

This molten lead delivery system <NUM> is believed to have the significant practical advantages of shielding and isolating the molten lead from the atmosphere, and virtually, if not completely, eliminating impurities and dross from the liquid lead supplied to the nozzle <NUM> and thus, avoiding deformation and defects which might otherwise be produced in the solid lead strip and ultimately battery grids made from the continuous solid lead strip.

While depicted and described for utilization in a horizontal orientation and configuration, the nozzle <NUM> could be equipped in a lead strip caster exhibiting a vertical configuration. Moreover, whether in a horizontal or vertical configuration, the nozzle <NUM> could be employed in a lead strip caster that need not necessarily include a ladle, and instead could receive molten lead from other types of molten lead delivery devices and systems that lack ladles such as molten lead feed-lines.

Claim 1:
A lead strip caster (<NUM>) for battery plate grids, the caster (<NUM>) comprising:
a supply (<NUM>) having an inlet (<NUM>) to receive molten lead and having an outlet (<NUM>), wherein the supply (<NUM>) comprises a pump (<NUM>) having the inlet (<NUM>) to receive molten lead and the outlet (<NUM>), the inlet (<NUM>) configured to be submerged in molten lead;
a nozzle (<NUM>) having a passage (<NUM>, <NUM>) that communicates with the outlet (<NUM>) of the supply (<NUM>) to receive molten lead from the supply (<NUM>);
a first roller (<NUM>) situated at a first exterior side of the nozzle (<NUM>), the first roller (<NUM>) is rotatable and has a first outer surface (<NUM>); and
a second roller (<NUM>) situated at a second exterior side of the nozzle (<NUM>), the second roller (<NUM>) is corotatable with the first roller (<NUM>) and the second roller (<NUM>) has a second outer surface (<NUM>);
a shoe (<NUM>) having an elongate outlet slot (<NUM>) communicating with the passage (<NUM>, <NUM>) of the nozzle (<NUM>), an inlet (<NUM>) communicating the slot (<NUM>) with the outlet (<NUM>) of the pump (<NUM>) and an outlet (<NUM>) communicating with the slot (<NUM>);
wherein, during use of the lead strip caster (<NUM>), molten lead exiting the passage (<NUM>, <NUM>) of the nozzle (<NUM>) comes into contact with the first outer surface (<NUM>) of the first roller (<NUM>) and comes into contact with the second outer surface (<NUM>) of the second roller (<NUM>), the molten lead hardening as it moves downstream of the passage (<NUM>, <NUM>) in contact with the first (<NUM>) and second outer surfaces (<NUM>), and
wherein during use of the lead strip caster (<NUM>), the pump (<NUM>) supplies to the inlet (<NUM>) of the shoe (<NUM>) an excess quantity of molten lead some of which flows through the outlet slot (<NUM>) into and through the passage (<NUM>, <NUM>) of the nozzle (<NUM>) and the rest of the excess molten lead flows through the outlet (<NUM>) of the shoe (<NUM>).