Patent Document

TECHNICAL FIELD 
     This pertains to the field of systems for treating wire in molten fluids, particularly molten lead. 
     BACKGROUND 
     In the course of heat treating wire it is sometimes beneficial to treat the wire in a molten fluid bath. When a molten lead bath is employed for annealing steel wire, elaborate heat control means are employed to maintain a proper lead temperature throughout the length of the bath. The lead bath is contained in an elongated trough. The wire that enters the bath is very hot and the bath quickly heats up as a result of the wire passing through it. One known method of attempting to maintain the lead bath temperature is directing fans at the warmer sections of the bath in an effort to cool them. This method can be inefficient for a number of reasons. Aiming the fan nozzles at specific hot spots is difficult. Even if the nozzles are directed at a specific hot spot, the spot may shift. Depending on the size of the bath, a large number of fans may be required which causes a great deal of power to be used to cool the bath. 
     Therefore it is desired that another method be used to be able to control temperature in the molten fluid bath. 
     Technical Summary 
     A first aspect of the disclosure features a system for heat treating metal wire. The system comprises a vessel that contains a molten fluid, a pump for circulating the molten fluid in the vessel, and a device that enables the wire to move through the molten fluid of the vessel. Reference to a wire in this disclosure is intended to cover any elongated article requiring treatment in a bath, including bundles of wires, braided wire and cable. The wire is typically made of metal. One example material of the metal wire is steel. The term “heat treating” as used in this disclosure means, for example, at least one of annealing, patenting, hardening, quenching and tempering, wherein the temperature of the wire is modified, that is, increased or decreased. 
     More specifically, in the first aspect of the disclosure the vessel is an elongated trough having a ratio of length to width of at least 5:1. The pump in the first aspect generally includes a motor, a pump shaft, a base that is submerged in the molten fluid, and an impeller. The pump shaft is connected to and driven by the motor. The base includes an impeller chamber, at least one inlet port, and at least one outlet port. The impeller is connected to the pump shaft and is rotatably disposed in the impeller chamber. An elongated discharge conduit is attached in alignment with the outlet of the base and extends outwardly from the base. The pump circulates the molten fluid in the vessel cooling the molten fluid in regions of the vessel. 
     Referring to further specific features of the first aspect, the molten fluid may be molten lead. The wire may be comprised of steel. The molten fluid may be maintained at a temperature permitting the wire to be heat treated (e.g., at least one of annealed or quenched) as a result of moving through the molten fluid. The pump may be offset from a centerline of the trough, for example, adjacent to an elongated edge of the trough. This facilitates passing wires through the trough without the pump being an obstruction. Multiple spaced apart wires may be passed at the same time through the trough and heat treated simultaneously. 
     In one specific variation, the discharge conduit may extend for at least 50% of the length of the trough. In another specific variation, the discharge conduit may extend for at least 75% of the length of the trough. In yet another specific variation, the discharge conduit may extend for at least 90% of the length of the trough. The length of the discharge conduit is measured outward from an external surface of the base (i.e., in a case of using two discharge conduit sections both sections would be included in the length). 
     Any of the features of the Detailed Description below can be combined with any of the specific features applicable to the first aspect described above, in any combination. 
     A second aspect of the disclosure employs an elongated vessel (e.g., having a ratio of length to width of at least 5:1). Any suitable pump can be employed in the second aspect, for example, a pump as described in the first embodiment, any pump sold by High Temperature Systems, Inc. or patented by inventor Bruno Thut. An elongated discharge conduit is attached to and extends outwardly from the pump. Conveyance structure enables the wire to be conveyed through the molten fluid. Operation of the pump enables the temperature of the molten fluid in the vessel to be changed (e.g., cooled) and the wire is heat treated as a result of passing through the (e.g., cooled) molten fluid. 
     Referring to specific features of the second aspect, the molten fluid can be molten lead. The wire can be comprised of steel. The vessel can have a ratio of length to width of at least 5:1 and the elongated discharge conduit can extend for at least 50% of the length of the vessel. The conveyance structure can include sets of rollers that enable the wire to be conveyed through the molten fluid; at least some of the rollers can be disposed in the molten fluid. 
     One advantage is that in this disclosure a molten fluid hot spot is maintained at about the same temperature as a molten fluid hot spot temperature in a conventional bath without using the pump but which employs conventional cooling means (e.g., fans). Alternatively, in this disclosure a molten fluid hot spot is maintained at a cooler temperature than a molten fluid hot spot temperature in a conventional bath without using the pump but which employs the conventional cooling means. For example, this cooler hot spot temperature is at least 50 degrees F. less than a conventional hot spot temperature, in particular, at least 20 degrees F. less than a conventional hot spot temperature, in particular, at least 10 degrees F. less than a conventional hot spot temperature. A hot spot temperature as used in this disclosure means a temperature of the molten fluid in the bath which is at a peak temperature of the molten fluid in the bath. A hot spot may reside in the bath near a location where the hot wire enters the bath. Because an elongated bath is used, the molten fluid will be cooler and more viscous or dense at a location remote from the hot spot. Moving cooler molten fluid to the hot spot with the pump having an elongated discharge conduit facilitates cooling the hot spot. General circulation may also cool the hot spot and may result in a more uniform temperature throughout the bath. 
     Any of the features described above in connection with the first aspect, and features of the Detailed Description below, can apply to the specific features applicable to the second aspect described above, in any combination. 
     A third aspect of the disclosure is directed to a method of treating a wire wherein the wire is conveyed through molten fluid contained in the vessel. The molten fluid is moved in the vessel so as to change a temperature (e.g., cool) the molten fluid in the vessel. The molten fluid is moved using a pump submerged in the molten fluid, the pump including the elongated discharge conduit in the vessel. The wire is heat treated as a result of moving through the (e.g., cooled) molten fluid. 
     Referring to specific features of the third aspect of the disclosure, the elongated discharge conduit can extend from the pump in a direction opposite a direction in which the wire is being conveyed. In another feature, the molten fluid can be molten lead. In another feature, rollers can be used to convey the wire through the molten fluid. 
     Still further, the vessel can be a trough having a ratio of length to width of at least 5:1. Another feature is that the discharge conduit can extend for at least 50% of the length of the vessel, in particular, for at least 75% of the length of the vessel, more particularly, for at least 90% of the length of the vessel. 
     Further features are that the pump can be located adjacent an elongated sidewall of the trough. Another feature is that the method moves with the pump cooler molten fluid to a hot spot of the molten fluid so as to carry out the cooling of the molten fluid. Still further, the hot spot can be near an entry location of the wire into the molten fluid contained in the vessel and the cooler molten fluid is remote from the entry location, comprising positioning an inlet of the pump near the location of the cooler molten fluid and positioning an outlet of the discharge conduit so as to discharge the cooler molten fluid into the hot spot of the molten fluid. Another feature is that the pump operates intermittently. Another feature is that the pump can circulate the molten fluid in the vessel. The pump could operate continuously resulting in general circulation that may result in a more uniform temperature throughout the bath. 
     In another feature, a temperature sensor can be placed near the wire entry location and this can be connected to a controller (e.g., a PLC or other suitable controller known in the art). A desired temperature range is programmed into the controller and the controller activates the pump to discharge cooler molten fluid into the hot spot when the temperature sensor senses a temperature outside the desired temperature range. In yet another feature the controller deactivates the pump when the temperature sensor senses a temperature in the desired temperature range. 
     The use of the pump to achieve cooling in the present system is advantageous in that it avoids the problems of the prior art which use energy intensive and inefficient fans for cooling. The present system and method require no use of fans for cooling. In addition, the present system would not have occurred to one skilled in the art for use with viscous or dense fluids, for example, molten lead. It would be expected to be difficult to move such viscous or dense molten fluids in the vessel. The present system and method avoid this problem using the pump with elongated discharge conduit. Moreover, the condition of the molten fluid (e.g., temperature, density and/or viscosity) can be controlled and adjusted in the present system and method, by carrying out at least one of the following: changing the rotational speed of the impeller, using different impellers, changing the length of the discharge conduit, changing a position and number of outlet openings in the discharge conduit, and by adjusting when the pump is operational. The present system also permits variations in design such as different shaped vessels, which may present advantages in production. Therefore, the present system and method provide a unique, energy efficient solution for use in a process for heat treating wire. 
     Many additional features, advantages, and a fuller understanding of the invention will be had from the accompanying drawings and the detailed description that follows. It should be understood that the above Technical Summary describes the disclosure in broad terms while the following Detailed Description describes the disclosure more narrowly and presents specific embodiments that should not be construed as necessary limitations of the invention as defined in the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a vertical cross-sectional view of a pump constructed according to the present disclosure; 
         FIG. 2  is a vertical cross-sectional view of a system made according to the present disclosure; 
         FIG. 3  is a top plan view of the system as shown in  FIG. 2 ; 
         FIG. 4  is a vertical cross-sectional view of a system made according to the present disclosure; and 
         FIGS. 5-7  are top plan views of systems made according to the present disclosure which employ vessels having different shapes. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure features a system  10  for heat treating metal wire  12 . A vessel  114  is filled with molten fluid  16  to create a bath for treating the wire  12 . A pump  18  for pumping the molten fluid  16  is placed in the vessel  114 . A motor mount  20  is disposed above the molten fluid  16  contained in the vessel  114 . A motor  22  is supported by the motor mount  20 . Submerged in the molten fluid  16  is a base  24  that includes an impeller chamber  26 . A molten fluid inlet opening  28  is disposed in the impeller chamber  26  and a molten metal outlet in the form of a discharge passageway  32  extends from the impeller chamber  26  to outlet orifice  30  at an exterior surface of the base  24 . The base  24  is submerged in the molten fluid  16 . The base  24  is connected to the motor mount  20  by support posts  34  that are attached to the base  24  and attached to the motor mount  20  as known in the art. A pump shaft  36  is connected to a drive shaft  38  of the motor  22  at one end via a coupling  40  as known in the art. An impeller  42  is connected to the other end of the pump shaft  36  and is rotatable in the impeller chamber  26 . The discharge passageway  32  that is inside the base is in fluid communication with an elongated discharge conduit  44  which extends outwardly from the base  24 . The elongated discharge conduit  44  extends for a distance at least equal to the length of the base  24 . A conveyance structure  45  is used in the system  10  for directing the wire  12  through the molten fluid  16  of the vessel  114 . It may be possible to direct the wires into the trough along a horizontal reference line below the bath surface, but this would require seals in the vessel that would prevent molten fluid from leaving the vessel. 
     The vessel  114  is partly filled with molten lead or other suitable molten fluid. The vessel  114  can comprise a substantially flat floor  46  and opposing sidewalls  48 . One embodiment of the vessel  114 , seen in  FIGS. 2 and 3 , comprises an elongated trough  50  with a length to width ratio of at least 5:1. The vessel  114  can have various shapes and configurations. Another embodiment of the vessel  214  comprises two parallel substantially straight, trough sections  52 ,  54  connected by a substantially curved trough section  56  as shown in  FIG. 5 . A further embodiment of the vessel comprises a partially curved trough  314  as shown in  FIG. 6 . Another embodiment comprises a vertically stepped trough  414  as shown in  FIG. 4 . In this design, the pump is located at the lowest elevation remote from the wire entry location while the wire inlet location is located at a highest elevation. This may enable the molten fluid to move by gravity down the elevation causing some inherent circulation. The elevation change has been exaggerated in this figure and may only be on the order of a few to several inches. A further embodiment of the vessel comprises a trough  514  that is substantially curved along its entire length  62  as shown in  FIG. 7 . The extent by which the wire can be curved, and the desired layout of the wire heat treating station, may affect which of the trough configurations is used. 
     The motor mount  20  can have various configurations and in this particular design comprises a flat mounting plate  64 . A hanger eye may be attached to the motor mount  20  or to the motor  22 . A hook (not pictured) on the end of a cable (not pictured) or the like is inserted into the hanger eye to hoist the pump  18  in and out of the vessel  14 . The motor  22  is an air motor, electric motor or the like, and is mounted onto the motor mount  20 . The motor mount plate  20  may optionally also include brackets  68  for supporting the motor  22  on an adaptor plate  70  above the flat motor mount plate  64  of the motor mount  20 . One or both of the adaptor plate  70  and the flat mounting plate  64  include openings  66  for the drive shaft  38 , a coupling and/or the pump shaft  36 . The upper end portion of the pump shaft  36  is coupled to the drive shaft  38  of the motor  22  using a detachable coupling  40  as known in the art, which rotates the impeller  42  in the impeller chamber  26 . The coupling may be above or below the motor mount plate  64 . An optional shaft sleeve (not pictured) can surround the shaft between the motor mount  20  and the base  24  as known in the art. In the example pump  18  design shown in the drawings no shaft sleeve is used. Because of the density of molten metal, especially molten lead, the motor  22  has as an example, a minimum power of 3-5 hp. The pump is adapted to accommodate pieces of metal being disposed in the molten fluid such as dislodged metal pieces of wire. 
     The impeller  42  is attached to one end portion of the pump shaft  36  such as by engagement of exterior threads  72  formed on the pump shaft  36  with corresponding interior threads  74  formed in the impeller  42 . However, any connection between the pump shaft  36  and the impeller  42 , such a key way or pin arrangement, or the like, may be used. Any suitable impeller may be used in the embodiment of the present system  10  including a squirrel cage impeller or a PENTELLER® brand impeller with vanes and a perforated impeller base or an imperforate impeller base as manufactured by High Temperature Systems Inc. The impeller shown in  FIG. 1  has perforations in the impeller base so that molten metal can enter the base through the perforations of the rotating impeller. The impeller  42  and/or pump shaft  36  can be made from heat-resistant material such as graphite. The pump  18 , including the base  24 , can be machined from steel. 
     The submerged base  24  is raised in a well known manner so that the base  24  does not rest on the floor  46  of the vessel  14 . The discharge passageway  32  is preferably tangential to the impeller chamber  26  as seen in a top view, as is known in the art. Openings are formed in upper and lower surfaces  76 ,  78  of the base  24  and the upper opening  76  receives the pump shaft  36 . An opening (not pictured) can surround the upper base inlet opening and receive the optional shaft sleeve. The upper and lower openings  76 ,  78  are concentric to one another relative to the central rotational axis A of the impeller  42 . 
     The disclosure is not limited to any particular pump  18  construction. It should be appreciated by one of ordinary skill in the art that any pump design manufactured by High Temperature Systems Inc. or patented by inventor Bruno Thut, may be suitable for use in the present disclosure. In this regard, upper and lower concentric openings can be formed in upper and lower surfaces  76 ,  78  of the base  24  and can be large enough to enable the impeller  42  to pass through them. The upper such opening can be an inlet opening into the base with the lower opening being optionally usable as an inlet opening, permitting the pump to be a top feed, bottom feed, or top and bottom feed pump. In  FIG. 1 , a shoulder is formed in the base  24  around the upper and lower base openings. Upper and lower bearing rings can be cemented to the respective upper and lower shoulders as known in the art. 
     The optional shaft sleeve can be cemented in place on the upper shoulder and the base  24  can include another surface for supporting the upper bearing ring as known in the art. The optional shaft sleeve can contain multiple inlet openings or a gap adjacent to the base  24  such as if gas is to be inlet down the shaft sleeve as in the case of the Poseidon™ pump manufactured by High Temperature Systems, Inc. 
     A lower end of the support post  34  is cemented in a socket or otherwise mechanically fastened to the base  24  and the upper end of the support post  34  is mounted to the motor mounting plate  64  as in quick release sockets, both as known in the art. 
     The internal discharge passageway  32  of the base  24  is in fluid communication with the external elongated discharge conduit  44 . The elongated discharge conduit  44  may comprise two sections,  44   a ,  44   b . The first discharge conduit section  44   a  is fastened to the base as by welding and is fastened to the second elongated discharge conduit section  44   b  such as by a bolted flange connection  80 . However, any suitable connection  80  between the second elongated discharge conduit  44   b  and the first discharge conduit  44   a  may be used. The discharge conduit sections  44   a  and  44   b  are exterior to the base. The elongated discharge conduit  44  extends in a shape configured to the embodiment of the vessel  114 , i.e., it may be straight and/or curved as shown in  FIGS. 2-7 . The elongated discharge conduit  44  may extend from the connection to the base  24  for any percentage of the length of the vessel  114 . In particular, the elongated discharge conduit  44  extends from the connection to the base  24  for at least 50% of the length of the vessel  114 . In all aspects of the disclosure the elongated discharge conduit  44  may only contain a single inlet port  82  (e.g., at the entrance to discharge conduit  44   a ) and a single outlet port  84  at the opposing end of the conduit  44   b , or it may contain a number of outlet openings  83  (e.g., see  FIG. 6 ) along some length of the conduit in addition to the inlet and outlet ports  82 ,  84 . The elongated discharge conduit  44  is prevented from resting on the floor  46  of the vessel  14  such as by brackets (not pictured); however, any suitable means may be used for this purpose. 
     The wire  12  is conveyed for treatment in the molten fluid  16  and through the vessel  14  such as by rollers. However, any suitable conveyance device for directing the wire  12  through the molten fluid  16  may be used. The conveyance device may change the path of the wire through the vessel vertically and/or horizontally. Rollers or other aspects of the conveyance device may be external to the molten fluid and optionally inside the molten fluid. The illustration of the rollers in the drawings is only schematic for aiding understanding. It should be appreciated that the rollers could be placed at various other locations and additional roller sets may be used, other than what is shown. 
     A method of treating wire  12  includes the following steps. The metal wire  12  is positioned and directed by the wire conveyance device. That is, the path of the wire changes from horizontal, downward into the vessel, along the vessel under the bath surface, then upward out of the vessel to a horizontal path again. Of course, the entry and exit paths when the wire is out of the vessel need not be horizontal. The metal wire  12  enters the vessel  14  at a wire entry point  86  and exits the vessel  114  at a wire exit point  88 . The method further includes the step of conveying the metal wire  12  along a conveyance path in the vessel  114 . It should be appreciated that various conveyance devices that are different than the rollers shown in the drawings, for directing the wire into and from the bath, and possibly within the bath, may be suitable for use in the present system. 
     The method further includes the step of connecting the discharge conduit  44   a  to the base  24  in alignment with the discharge orifice  30 . The inlet opening  28 , the discharge passageway  32 , and the elongated discharge conduit  44  of the base  24  are submerged in the molten fluid  16 . The pump shaft  36  is driven by operating the motor  22 , which rotates the impeller  42  in the impeller chamber  26 . Rotation of the impeller  42  causes the molten fluid  16  to flow into the impeller chamber  26  through the inlet opening  28  and from the impeller chamber  26  into the discharge passageway  32  and further through outlet orifice  30  into the inlet orifice  82  of the connected discharge conduit section  44   a  to the elongated discharge conduit  44   b  from which it enters the vessel  14  through discharge conduit outlet  84  and/or through openings  83 . The impeller  42  rotates at any suitable rotational speed. 
     As further illustrated, the pump  18  may be placed adjacent to the wire exit point and the elongated discharge conduit  44   b  may extend from the base  24  in a direction toward the wire entry point. On the other hand, the pump  18  might be placed adjacent to the wire entry point with the conduit extending toward the wire exit point. The pump  18  may be placed adjacent to the sidewall  48  with the discharge conduit  44  extending adjacent to the same sidewall  48  so as to not impede the conveyance path. However, any suitable placement of the pump  18  and conduit may be used. 
     The method optionally includes the step of monitoring the temperature of the molten fluid  16  and maintaining the temperature in a range to allow treatment of the wire  12 . A particular example temperature of the molten fluid  16  is in a range between 900-1000 degrees Fahrenheit; however any suitable temperature for treating the wire  12  may be used. A temperature at the wire entry/or and exit locations may be monitored and regulated. For example, the pump  18  may pump cooler molten lead so as to enter the inlet opening  28  of the base  24  near the wire exit end portion of the vessel, or other location in the vessel, to travel along the elongated discharge conduit  44   b  and to discharge from the elongated discharge conduit  44   b  through outlet  84  and/or outlets  83  at a region near a hot spot  90  in the bath, for example, near the wire entry location  86 . A temperature sensor  92  may be placed at the hot spot  90  and may be connected to the pump  18  via connection with a PLC  94 . A desired temperature range for the hot spot  90  may be selected and programmed into the PLC. The pump  18  may be placed in the vessel such that the molten inlet opening  28  would be placed in the cooler molten fluid and the outlet port  84  of the elongated discharge conduit  44  would be located adjacent to the hot spot  90 . The PLC  94  may be programmed to activate the pump  18  to pump the cooler molten fluid to the hot spot  90  until the hot spot  90  is within the desired temperature range. The PLC  94  may then deactivate the pump  18 . On the other hand, the PLC may operate to control or monitor overall temperature in the bath rather than at a hot spot. 
     The molten fluid  16  exits the outlet port  84  of the conduit at a pressure sufficient to mix with the molten fluid  16  in the vessel  14 , for example to cause circulation of the molten fluid  16  in the vessel  14 . This mixing can cause a mixed molten fluid  16  to flow in a direction opposite a path of the molten fluid  16  exiting the outlet port  84  of the elongated discharge conduit  44  (e.g., from the wire inlet location toward the wire outlet location). The mixed molten fluid  16  in the vessel  14  can flow in a direction toward the inlet opening  28  of the base  24 . The pump may operate intermittently or continuously; this may permit some temperature variation in the bath or achieve a relatively uniform bath temperature compared to the prior art system, respectively. No fans need to be employed in the system of the present disclosure. 
     Many modifications and variations of the disclosed subject matter will be apparent to those of ordinary skill in the art in light of the foregoing disclosure. Therefore, it is to be understood that, within the scope of the appended claims, the invention can be practiced otherwise than has been specifically shown and described.

Technology Category: 8