SENSOR CONTROLLED LAUNDER FLOW

Abstract

According to a first embodiment, a molten metal transferring system is provided. The system includes a device capable of lifting molten metal from a bath to a launder at varying quantity per unit of time. The system includes a sensor, such as a laser, arranged to monitor molten metal flow in the launder. The launder further includes a removeable insert facilitating, reversible modification of a cross-sectional area of the launder.

Claims

1. A molten metal transferring system comprising a device capable of lifting molten metal from a bath to a launder at varying quantity per unit of time, said system including a laser arranged to monitor a molten metal level in said launder, wherein said launder further includes a removeable insert facilitating reversible modification of a cross-sectional area of the launder.

2. The system of claim 1 wherein the device comprises an overflow transfer pump.

3. The system of claim 1 wherein the device comprises a launder transfer pump.

4. The system of claim 1 wherein the device comprises a lift pump.

5. The system of claim 1 wherein said launder is in fluid communication with a ladel.

6. The system of claim 1 wherein said launder is in fluid communication with a die casting machine.

7. The system of claim 1 wherein said launder is in fluid communication with a mold.

8. The system of claim 1 wherein the insert comprises a bracket having a first end secured to the launder and a second end secured to a body disposed in a flow path defined by the launder.

9. The system of claim 8, wherein at least one of the first end or the second end includes a quick-release connection.

10. The system of claim 8 wherein the body is comprised of a refractory material.

11. The system of claim 8 wherein the body includes a substantially rounded surface.

12. A molten metal furnace for delivering molten metal to a downstream process, comprising: a heating chamber configured to contain and heat a supply of the molten metal; a variable speed pump, the pump having a pump inlet in fluid communication with the heating chamber and a pump outlet in fluid communication with a launder, said launder including a removeable insert for adjusting a cross-sectional area of the launder; a molten metal level sensor located in association with the launder and connected to the pump or a controller of the pump for providing a pump speed control signal, the level sensor configured to monitor the level of the molten metal in the launder upstream of the insert when present.

13. The furnace of claim 12 wherein the insert is connected to the launder by a bracket.

14. The furnace of claim 13 wherein the bracket includes a quick-release connection to at least one of the insert or launder.

15. The furnace of claim 12 wherein the insert includes a substantially rounded surface.

16. The furnace of claim 12 wherein the sensor comprises a laser.

17. The furnace of claim 12 wherein the insert is comprised of a refractory material.

18. The furnace of claim 12 wherein the insert blocks at least 10% of a flow path of the launder.

19. A process for transporting molten metal from a furnace to at least two different vessels, comprising: providing a heating chamber configured to contain and heat a supply of the molten metal; providing a variable speed pump, the pump having a pump inlet in fluid communication with the heating chamber and a pump outlet in fluid communication with a launder, said launder including a removeable insert for adjusting a cross-sectional area of the launder; a molten metal level sensor located in association with the launder and connected to the pump or a controller of the pump for providing a pump speed control signal, the level sensor configured to monitor the level of the molten metal in the launder upstream of the insert when present, wherein in either order (I) molten metal is transported through the launder to a relatively larger of the vessels without the insert present and (ii) molten metal is transported through the launder to a relatively smaller of the vessels with the insert present.

20. The process of claim 16 wherein the vessel is a mold, a ladel or a crucible.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The following is a brief description of the drawings, which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same.

[0013] FIGS. 1(A-B) illustrate a three mold system of the prior art employing sensors to determine molten metal height in molds;

[0014] FIG. 2 illustrates an exemplary pumping system in accord with the present disclosure; and

[0015] FIG. 3 schematically illustrates control of metal height in the feed launder by a sensor arrangement.

DETAILED DESCRIPTION

[0016] A more complete understanding of the components, processes and apparatuses disclosed herein can be obtained by reference to the accompanying drawings. These figures are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are, therefore, not intended to indicate relative size and dimensions of the devices or components thereof and/or to define or limit the scope of the exemplary embodiments.

[0017] Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings, and are not intended to define or limit the scope of the disclosure. In the drawings and the following description below, it is to be understood that like numeric designations refer to components of like function.

[0018] The singular forms a, an, and the include plural referents unless the context clearly dictates otherwise.

[0019] As used herein, the terms about, generally and substantially are intended to encompass structural or numerical modifications which do not significantly affect the purpose of the element or number modified by such term.

[0020] As used in the specification and in the claims, the term comprising may include the embodiments consisting of and consisting essentially of. The terms comprise(s), include(s), having, has, can, contain(s), and variants thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that require the presence of the named ingredients/steps and permit the presence of other ingredients/steps. However, such description should be construed as also describing compositions or processes as consisting of and consisting essentially of the enumerated ingredients/steps, which allows the presence of only the named ingredients/steps, along with any impurities that might result therefrom, and excludes other ingredients/steps.

[0021] FIGS. 1A & B illustrate a prior art system employing sensors to determine molten metal height in molds. The system of FIGS. 1A & B is described herein because many features depicted are common to the present disclosed invention.

[0022] With continuing reference to FIGS. 1A and 1B, a three mold system is shown (molds 102, 103 and 104). A sensor 100, typically a laser triangulation based sensor is attached to each of the molds 102, 103, 104 and positioned to measure the height of molten metal surface 105 in the molds. Launder 101 delivers molten metal to each mold via down spouts 107, 108 and 109. Controller 115 reads out the data from sensor(s) 100 and using a pin type actuator/stopper(s) 116 controls the flow of metal into the mold(s) 102, 103, and 104.

[0023] In the present embodiment, the sensor is employed to monitor the quantity of molten metal in the launder and in combination with a controller, to adjust the pump RPM to stop, increase or decrease the quantity of molten metal delivered to the launder. More particularly, the present disclosure can utilize the sensor(s) and controller to adjust the RPM of an associated pumping system. An important operational parameter is the measured height of metal in launder, which relates to a pour rate.

[0024] Laser type electro-optical sensors are effective for monitoring molten metal height. One sensor, or alternatively, multiple sensors can be used for this purpose. However, as discussed above, sensing can be difficult when the level of molten metal in the launder is low due to turbulence and reflections. Accordingly, in a low metal flow condition, the quantity of molten metal delivered from the launder can be more problematic to control.

[0025] Moreover, It has been found that a dilemma encountered by systems that use laser sensing of molten metal is that insufficient molten metal can yield inaccurate calculation of metal depth and/or flow rate. It has been found that control of the height of metal in the feeding launder can improve system performance. This height control can be accomplished by providing the launder assembly with a removeable insert, particularly for use when the molten metal level in the launder is anticipated to be low, such as when filling a low volume mold(s). The removeable insert functions to narrow the cross-section of the launder, causing an upstream increase in molten metal depth in the region in which the sensor is directed.

[0026] Referring now to FIG. 2, an exemplary pumping system 200 is illustrated. In this embodiment, an overflow transfer pump 202 feeds molten metal to launder 204. Removable insert 206 is provided to reduce the cross-sectional area of the launder flow channel 208. In select embodiments, the insert will reduce the cross-sectional area of the launder flow path by at least 10%, or 25%, or 33%. Laser 210 is aimed into region 212 where molten metal depth is increased via the presence of the insert 206. Two or more sensors spanning different region(s) can be used.

[0027] Insert 206 is secured to the launder via a removeable bracket 214. In certain embodiments, it is envisioned that the bracket will be secured to either or both the launder and/or the insert using a quick-release connection such as a pin(s), clamp or interference fit. Insert 206 can be removed during casting operations where a relatively large quantity of molten metal is flowing through the launder, for example, during billet casting (greater than 100 lbs). As a further example, the insert can be removed during and a furnace empty operation where at least substantially the entire volume of molten metal is emptied into a sow. Insert 206 can be inserted into the launder when a relatively low level of molten metal is passing through the launder, such as during small ingot casting (less than 50 lbs). As a further example, a small ingot that is only a few pounds may be formed using a relatively low flow where the insert is employed

[0028] Sensor 210 can include an information connection link 216 suitable for providing molten metal depth and/or flow rate information to a controller 220 which in turn can control the motor 218 driving the pumping member of pump 202. More particularly, the controller can determine how fast (RPM) the motor should operate to increase or decrease the volume of molten metal passing through the launder based on the requirements of the associated casting operation being performed. Casting efficiency and molten metal quality can be greatly improved in this manner.

[0029] In FIG. 3 a profiling laser sensor 304 is placed above the feed launder 301 and used to determine the height of molten metal 310 at multiple transverse locations in the launder with respect to the launder top surface 320 (or other suitable point on the launder). The reference surface, in this case surface 320, can be measured in its position at one point, or at a number of positions using a plurality of spots or along a continuous line of light. In accord with this disclosure, at least one position will be upstream of a removeable insert.

[0030] The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

[0031] To aid the Patent Office and any readers of this application and any resulting patent in interpreting the claims appended hereto, applicants do not intend any of the appended claims or claim elements to invoke 35 U.S.C. 112(f) unless the words means for or step for are explicitly used in the particular claim.