Sensor-controlled sump flow

Abstract

According to a first embodiment, a molten metal delivery system is provided. The system includes a device capable of lifting molten metal from a bath to a runner in varying amounts per unit time. The system includes a sensor, such as a laser, for monitoring the flow of molten metal in the runner. The runner further includes a removable insert to facilitate reversible modification of the cross-sectional area of the runner.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 916,502, filed October 17, 2019, the disclosure of which is hereby incorporated by reference. Background Art

[0003] This exemplary embodiment relates to a molten metal pumping system. Pumps for pumping molten metal are used in furnaces used in the production of metal products. Common functions of pumps are to circulate molten metal within the furnace or to transport molten metal to a remote location. The present description focuses on molten metal pumps used to transport metal from one location to another. This invention is particularly relevant to systems that elevate molten metal from a furnace pool to a launder system.

[0004] Currently, many metal die casting facilities utilize a main hearth that contains the majority of the molten metal. Solid metal bars are periodically melted in the main hearth. A transfer pump may be located in a wellhead near the main hearth. The transfer pump draws the molten metal from the wellhead and transfers it to a pipe (in many cases, a launder), from which it is delivered to a ladle, mold, or die casting machine where the metal product is formed.

[0005] The present disclosure relates to pumps for conveying molten metal from a furnace to a die casting machine, an ingot mold, a ladle, etc. For example, the present disclosure may employ pumping systems of the type described in US Pat. No. 10,415,884, US Pat. No. 10,072,891, US Pat. No. 9,909,808, US Pat. No. 9,982,945, and US Pat. No. 10,352,620, the disclosures of which are incorporated herein by reference.

[0006] Typically, a launder is used to transport the melt from the furnace to the casting location via a pumping system. A launder is essentially a groove, channel, or conduit outside a reverberatory furnace. A launder can be used to transport molten metal from the furnace into a ladle and / or mold. A launder can be of any size or shape. For example, it can be one foot long or up to 100 feet long. A launder is typically slightly inclined, for example, it can slope downward or upward. In use, a typical launder contains molten aluminum at a depth of approximately 1-10 inches.

[0007] When a transfer pump is used to feed a launder, the pump is turned off, on, and accelerated depending on when more molten metal is needed. This can be done automatically. If automated, the pump can be turned on and / or accelerated when the molten metal in the launder falls below a certain desired level. In some cases, a laser is used for this purpose.

[0008] However, it has been determined that the accuracy of the laser readings can become problematic when the molten metal in the launder is at a lower level (e.g., less than 2 inches). Since common launders are often used interchangeably to fill both large mold pieces (e.g., billets) and small castings (e.g., ingots), the launders can be used to deliver large or small amounts of molten metal. A launder configured to deliver large amounts of metal inherently has a lower level of molten metal when delivering small amounts of molten metal. This results in inaccurate laser readings for automatic pump control. The present disclosure is directed to solving this problem. SUMMARY

[0009] Various details of the disclosure are summarized below to provide a basic understanding. This summary is not an extensive overview of the disclosure, is not intended to identify certain elements of the disclosure, nor is it intended to describe a scope of the disclosure. Rather, the primary purpose of this summary is to present some concepts of the disclosure in a simplified form, before the more detailed description is given below.

[0010] According to a first embodiment, a molten metal delivery system is provided. The system includes a device capable of lifting molten metal from a bath to a launder in varying amounts per unit time. The system includes a sensor (such as a laser) arranged to monitor the level of molten metal in the launder. The launder further includes a removable insert to facilitate reversible modification of the cross-sectional area of the launder.

[0011] According to a second embodiment, a molten metal furnace for delivering molten metal to a downstream location is provided. The furnace includes a heated chamber configured to receive and heat a supply of molten metal and a variable speed pump in fluid communication with the heated chamber. The pump includes a pump inlet connected to the heated chamber and a pump outlet connected to a launder. The launder includes a removable insert for adjusting the cross-sectional area of the launder. A molten metal level sensor is positioned in association with the launder and connected to the pump for providing a pump speed control signal. The level sensor is configured to monitor the level of molten metal in the launder and control the speed of the pump via the pump speed control signal to maintain a predetermined level of molten metal in the launder.

[0012] According to another embodiment, a process is provided for transporting molten metal from a furnace to at least two different vessels. The process provides a heating chamber configured to receive and heat a supply of molten metal. The process provides a variable speed pump having a pump inlet in fluid communication with the heating chamber and a pump outlet in fluid communication with a flow channel. The flow channel includes a removable insert for adjusting the cross-sectional area of the flow channel. A level sensor is positioned in association with the flow channel and is connected to the pump or a controller of the pump for providing a pump speed control signal. The level sensor is configured to monitor the level of molten metal, if any, in the flow channel upstream of the insert, wherein either (i) the molten metal is transported through the flow channel to a larger vessel in which the insert is not present, or (ii) the molten metal is transported through the flow channel to a smaller vessel in which the insert is present. BRIEF DESCRIPTION OF DRAWINGS

[0013] The following is a brief description of the drawings that are intended to illustrate, but not limit, the exemplary embodiments disclosed herein.

[0014] FIGS. 1A-1B illustrate three prior art mold systems that employ sensors to determine the level of molten metal in the mold;

[0015] Figure 2 An exemplary pumping system consistent with the present disclosure is illustrated; and

[0016] Figure 3 Controlling the level of metal in a feed channel by a sensor arrangement is schematically illustrated. DETAILED DESCRIPTION

[0017] A more complete understanding of the components, processes and apparatuses disclosed herein can be obtained from a consideration of the following detailed description when taken in conjunction with the drawing figures. The figures are merely schematic representations based on convenience and the ease of demonstrating the present disclosure, and are 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.

[0018] For the purposes of clarity, not all of the structural components of the embodiments described herein are shown, and some of the figures can be simplified for the sake of clarity. In general, the drawings and discussion enter the scope of the disclosure and are intended to provide further clarification in connection with the exemplary embodiments. While specific terminology is employed by way of example in the description, this is done for the purposes of clarity and is not intended to limit the scope of the disclosure. In the drawings and the description below, like numbers refer to like elements, unless the context clearly dictates otherwise.

[0019] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0020] The terms "about," "generally," and "substantially" as used herein are intended to permit a modification of structure and number that does not materially affect the use of the element or number being modified by such term.

[0021] The term "comprising" as used in the specification and in claims includes embodiments of "consisting essentially of" and "consisting of." The terms "comprise," "contain," "have," "hold," "include," "may," "store," and "tabulate," as well as variations 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 is also to be understood to describe compositions or processes that consist of or consist essentially of the recited ingredients / steps, which permits only the specified ingredients / steps and any impurities that can arise from the recited ingredients / steps, and excludes other ingredients / steps.

[0022] FIGS. 1A and IB illustrate a prior art system that employs sensors to determine the level of molten metal in a mold. The system of FIGS. 1A and IB is described herein because many of the features described are common to the general features of the present disclosure.

[0023] With continued reference to FIGS. 1A and IB, three mold systems (molds 102, 103, and 104) are shown. A sensor 100, typically a laser triangulation based sensor, is attached to each mold 102, 103, 104 and positioned to measure the height of the molten metal surface 105 in the mold. A trough 101 delivers molten metal to each mold via lower spouts 107, 108, and 109. A controller 115 reads data from the sensors 100 and uses pin actuators / brakes 116 to control the flow of metal into the molds 102, 103, and 104.

[0024] In the present embodiment, a sensor is employed to monitor the amount of molten metal in the trough and, in conjunction with a controller, adjust the revolutions per minute of the pump to stop, increase, or decrease the amount of molten metal delivered to the trough. More specifically, the present disclosure can utilize a sensor and a controller to adjust the revolutions per minute of an associated pumping system. An important operating parameter is the measured height of the metal in the trough, which is related to the pouring rate.

[0025] Laser-type electro-optical sensors are effective for monitoring the height of molten metal. One sensor or, alternatively, multiple sensors can be used for this purpose. However, as noted above, the sensing can be difficult when the level of molten metal in the trough is low due to turbulence and reflections. Accordingly, the amount of molten metal delivered from the trough can be more difficult to control under low metal flow conditions.

[0026] Furthermore, it has been found that systems using molten metal laser sensing experience difficulties in that insufficient molten metal can result in inaccurate metal depth and / or flow rate calculations. It has been found that control of the metal level in the feed launder can improve system performance. Such level control can be achieved by providing removable inserts for the launder assembly, particularly for use when the level of molten metal in the launder is expected to be low, such as during the filling of small volume molds. The removable insert function reduces the cross section of the launder, resulting in an increase in the depth of molten metal upstream of the area to which the sensor is directed.

[0027] Referring now to the drawings Figure 2 An exemplary pumping system 200 is shown. In this embodiment, an overflow delivery pump 202 feeds molten metal to a launder 204. A removable insert 206 is provided to reduce the cross-sectional area of the launder flow passage 208. In selected embodiments, the insert will reduce the cross-sectional area of the launder flow path by at least 10%, 25%, or 33%. A laser 210 is directed at an area 212 in which the depth of molten metal is increased via the presence of the insert 206. Two or more sensors spanning different areas can be used.

[0028] The insert 206 is secured to the launder via a removable bracket 214. In certain embodiments, it is contemplated that a quick release connection, such as a pin, a clamp, or an interference fit, will be used to secure the bracket to the launder or to the insert or to both the launder and the insert. During casting operations in which a relatively large amount of molten metal is flowing through the launder, such as during billet casting (greater than 100 pounds), the insert 206 can be removed. As a further example, during furnace emptying operations in which at least substantially the entire volume of molten metal is emptied into a sow, the insert can be removed. When a relatively low level of molten metal is passing through the launder, such as during small ingot casting (less than 50 pounds), the insert 206 can be inserted into the launder. As a further example, at locations where the insert is employed, relatively low flow can be used to form small ingots of only a few pounds.

[0029] The sensor 210 can include an information connection link 216 that is adapted to provide molten metal depth and / or flow rate information to a controller 220, which in turn can control a motor 218 to drive the pumping member of the pump 202. More particularly, the controller can determine how fast (revolutions per minute) the motor should operate to increase or decrease the volume of molten metal passing through the launder, depending on the requirements of the associated casting operation being performed. In this manner, casting efficiency and molten metal quality can be greatly improved.

[0030] In Figure 3In this case, the profile laser sensor 304 is placed above the supply launder 301 to determine the height of the molten metal 310 at a plurality of lateral locations in the launder relative to the top surface 320 of the launder (or other suitable point on the launder). The reference surface (in this case surface 320) can be measured at one point in its location, or using multiple light points or along a continuous light line at multiple locations. According to the present disclosure, at least one location is upstream of the removable insert.

[0031] The exemplary embodiments have 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 embodiments be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

[0032] To the extent that the appended claims recite "a," "an," "the" or "at least one" with reference to certain features, this is used generically to describe multiple possible embodiments and should be taken as referring to one or more than one (i.e., to "at least one") of the features. To the extent that the phrase "one or more" appears herein, it is used generically to describe one or more than one (i.e., to "at least one"). The application is not limited to the embodiments described herein but can vary and include any alternatives to the features described or concepts inherent in the application. The word "comprising" and variations such as "comprise" or "comprises" is not used as a limitation in any way, and does not exclude additional unrecited elements or method steps.

Claims

1. A process for transferring molten metal from a furnace to at least two different containers, comprising: providing a heating chamber configured to receive and heat a supply of molten metal; providing a variable speed pump having a pump inlet in fluid communication with the heating chamber and a pump outlet in fluid communication with a flow channel, the flow channel including a removable insert for adjusting a cross-sectional area of ​​the flow channel; positioning a molten metal level sensor in association with the launder and connecting it to the pump or a controller of the pump for providing a pump speed control signal, the molten metal level sensor being configured to monitor the level of molten metal in the launder upstream of the insert when the insert is present, Either the molten metal is conveyed through the launder to a larger container where no insert is present, in sequence i, or the molten metal is conveyed through the launder to a smaller container where an insert is present, in sequence ii.

2. A process according to claim 1, wherein the device comprises an overflow transfer pump.

3. The process of claim 1 wherein the apparatus comprises a launder transfer pump.

4. The process of claim 1 wherein the apparatus comprises a lift pump.

5. The process of claim 1 , wherein the launder is in fluid communication with a ladle.

6. The process of claim 1 wherein the removable insert comprises a bracket having a first end secured to the flow channel and a second end secured to a body disposed in the flow path defined by the flow channel.

7. The process of claim 6, wherein at least one of the first end or the second end comprises a quick release connection.

8. The process of claim 6, wherein the body is composed of a refractory material.

9. The process of claim 6, wherein the body comprises a substantially circular surface.

10. The process of claim 1 wherein the molten metal level sensor comprises a laser.

11. The process of claim 1 , wherein the insert blocks at least 10% of the flow path of the flow cell.

12. The process of claim 1, wherein the container is a mold, a ladle or a crucible.

Images