MOLTEN METAL CONTROLLED FLOW LAUNDER

Abstract

A launder for use in moving molten metal includes at least one relatively narrow channel through which molten metal flows. Using a narrow, rather than broad, channel permits better control of the flow and helps prevent overflowing the launder or a structure adjacent the launder. A molten metal pumping or transfer system may utilize a launder as disclosed herein.

Claims

1. A launder for use in moving molten metal, the launder comprising: (a) graphite or ceramic; (b) a channel configured to transfer molten metal, the channel having an upper cross-sectional area and a lower cross-sectional area, the lower cross-sectional area being smaller than the upper cross-sectional area.

2. The launder of claim 1, wherein the channel is V-shaped.

3. The launder of claim 1, wherein the channel is U-shaped.

4. The launder of claim 1 that is comprised of ceramic.

5. The launder of claim 1, wherein the channel is centered in the launder.

6. The launder of claim 1, wherein the top of the channel has a channel width and top of launder has a launder width, and the channel width is 50% or more of the launder width.

7. The launder of claim 1, wherein the top of the channel has a channel width and top of launder has a launder width, and the channel width is 50% or less of the launder width.

8. The launder of claim 1 that comprises a plurality of channels.

9. The launder of claim 8, wherein each of the plurality of channels is V-shaped.

10. The launder of claim 1 that further includes a launder height and a channel height and the channel height is 50% or more of the launder height.

11. The launder of claim 1 that further includes a launder height and a channel height and the channel height is 50% or less of the launder height.

12. The launder of claim 2, wherein each side of the V-shaped channel is formed at an angle of 30 degrees-60 degrees from the horizontal axis.

13. The launder of claim 2, wherein each side of the V-shaped channel is formed at an angle of 45 degrees from the horizontal axis.

14. A molten metal pump transfer system including the launder of claim 1.

15. The launder of claim 1 that further comprises a grate in the channel, wherein the grate is configured to filter solid pieces from molten metal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a cross-sectional side view of an exemplary system according to this disclosure.

[0016] FIG. 2 is the system of FIG. 1 showing the level of molten metal in the furnace being increased.

[0017] FIG. 2A shows the system of FIGS. 1 and 2 and displays how heights H1 and H2 are determined.

[0018] FIG. 3 is a top view of the system of FIG. 1.

[0019] FIG. 3A is a partial, side, cross-sectional view of a system according to an embodiment of this disclosure.

[0020] FIG. 4 is an end view of a launder according to an embodiment this disclosure.

[0021] FIG. 5 is an end view of an alternate launder of this disclosure.

[0022] FIG. 6 is an end view of an alternate launder of this disclosure.

[0023] FIG. 7 is an end view of an alternate launder of this disclosure.

[0024] FIG. 8 is a side view of the launder of FIG. 4.

[0025] FIG. 9 is a top view of the launder of FIG. 4.

[0026] FIG. 10 is a side view of the launder of FIG. 5.

[0027] FIG. 11 is a top view of the launder of FIG. 5.

[0028] FIG. 12 is a side view of the launder of FIG. 6.

[0029] FIG. 13 is a top view of the launder of FIG. 6.

[0030] FIG. 14 is a side view of the launder of FIG. 7.

[0031] FIG. 15 is a top view of the launder of FIG. 7.

DETAILED DESCRIPTION

[0032] Turning now to the Figures, wherein the purpose is to describe preferred embodiments of the invention and not to limit same, FIGS. 1-3A show a system 10 for moving molten metal M out of a vessel and into a launder. System 10 includes a furnace 1 that can retain molten metal M, which includes a holding furnace 1A, a vessel 12, a launder 20, and a pump 22. System 10 preferably has a vessel 12, a dividing wall 14 to separate vessel 12 into at least a first chamber 16 and a second chamber 18, and a device or structure, which may be pump 22, for generating a stream of molten metal from first chamber 16 into second chamber 18.

[0033] Using heating elements (not shown in the figures), furnace 1 is raised to a temperature sufficient to maintain the metal therein (usually aluminum or zinc) in a molten state. The level of molten metal M in holding furnace 1A and in at least part of vessel 12 changes as metal is added or removed to furnace 1A, as can be seen in FIG. 2.

[0034] For explanation, furnace 1 includes a furnace wall 2 having an archway 3. Archway 3 allows molten metal M to flow into vessel 12 from holding furnace 1A. In this embodiment, furnace 1A and vessel 12 are in fluid communication, so when the level of molten metal in furnace 1A rises, the level also rises in at least part of vessel 12. It most preferably rises and falls in first chamber 16 as the level of molten metal rises or falls in furnace 1A.

[0035] Dividing wall 14 separates vessel 12 into at least two chambers, a pump well (or first chamber) 16 and a skim well (or second chamber) 18, and any suitable structure for this purpose may be used as dividing wall 14. As shown in this embodiment, dividing wall 14 has an opening 14A and an optional overflow spillway 14B (best seen in FIG. 3), which is a notch or cut out in the upper edge of dividing wall 14. Overflow spillway 14B is any structure suitable to allow molten metal to flow from second chamber 18, past dividing wall 14, and into first chamber 16 and, if used, overflow spillway 14B may be positioned at any suitable location on wall 14. The purpose of optional overflow spillway 14B is to prevent molten metal from overflowing the second chamber 18, or a launder in communication with second chamber 18 (if a launder is used with the invention), by allowing molten metal in second chamber 18 to flow back into first chamber 16. Optional overflow spillway 14B would not be utilized during normal operation of system 10 and is to be used as a safeguard if the level of molten metal in second chamber 18 improperly rises to too high a level.

[0036] Second chamber 18 has a wall portion 18A, which has a height H2, wherein H2 is less than H1 (as can be best seen in FIG. 2A) so during normal operation molten metal pumped into second chamber 18 flows past wall portion 18A and out of second chamber 18 rather than flowing back over dividing wall 14 and into first chamber 16.

[0037] At least part of dividing wall 14 has a height H1 (best seen in FIG. 2A), which is the height at which, if exceeded by molten metal in second chamber 18, molten metal flows past the portion of dividing wall 14 at height H1 and back into first chamber 16. In the embodiment shown in FIGS. 1-3A, overflow spillway 14B has a height H1 and the rest of dividing wall 14 has a height greater than H1. Alternatively, dividing wall 14 may not have an overflow spillway, in which case all of dividing wall 14 could have a height H1, or dividing wall 14 may have an opening with a lower edge positioned at height H1, in which case molten metal could flow through the opening if the level of molten metal in second chamber 18 exceeded H1. H1 should exceed the highest level of molten metal in first chamber 16 during normal operation.

[0038] Dividing wall 14 may also have an opening 14A that is located at a depth such that opening 14A is submerged within the molten metal during normal usage, and opening 14A is preferably near or at the bottom of dividing wall 14. Opening 14A preferably has an area of between 6 in..sup.2 and 24 in..sup.2, but could be any suitable size. Further, dividing wall 14 need not have an opening if a transfer pump were used to transfer molten metal from first chamber 16, over the top of wall 14, and into second chamber 18 as described below.

[0039] Dividing wall 14 may also include more than one opening between first chamber 16 and second chamber 18 and opening 14A (or the more than one opening) could be positioned at any suitable location(s) in dividing wall 14 and be of any size(s) or shape(s) to enable molten metal to pass from first chamber 16 into second chamber 18.

[0040] Molten metal pump 22 may be any device or structure capable of pumping or otherwise conveying molten metal, and may be a transfer, circulation or gas-release pump. Pump 22 is preferably a circulation pump (most preferred) or gas-release pump that generates a flow of molten metal from first chamber 16 to second chamber 18 through opening 14A. Pump 22 generally includes a motor 24 surrounded by a cooling shroud 26, a superstructure 28, support posts 30 and a base 32. Some pumps that may be used with the invention are shown in U.S. Pat. Nos. 5,203,681, 6,123,523 and 6,354,964 to Cooper, and pending U.S. application Ser. No. 10/773,101 to Cooper. Molten metal pump 22 can be a constant speed pump, but is most preferably a variable speed pump. Its speed can be varied depending on the amount of molten metal in a structure such as a ladle or launder, as discussed below.

[0041] Utilizing system 10, as pump 22 pumps molten metal from first chamber 16 into second chamber 18, the level of molten metal in chamber 18 rises. When a pump with a discharge submerged in the molten metal bath, such as circulation pump or gas-release pump is utilized, there is essentially no turbulence or splashing during this process, which reduces the formation of dross and reduces safety hazards. The flow of molten metal is smooth and generally at an even flow rate.

[0042] If pump 22 is a circulation pump or gas-release pump, it is preferably at least partially received in opening 14A in order to at least partially block opening 14A in order to maintain a relatively stable level of molten metal in second chamber 18 during normal operation and to allow the level in second chamber 18 to rise independently of the level in first chamber 16. Utilizing this system the movement of molten metal from one chamber to another and from the second chamber into a launder does not involve raising molten metal above the molten metal surface. As previously mentioned this alleviates problems with blockage forming (because of the molten metal cooling and solidifying), and with turbulence and splashing, which can cause dross formation and safety problems. As shown, part of base 32 (preferably the discharge portion of the base) is received in opening 14A. Further, pump 22 may communicate with another structure, such as a metal-transfer conduit, that leads to and is received partially or fully in opening 14A. Although it is preferred that the pump base, or communicating structure such as a metal-transfer conduit, be received in opening 14A, all that is necessary for the invention to function is that the operation of the pump increases and maintains the level of molten metal in second chamber 18 so that the molten metal ultimately moves out of chamber 18 and into another structure. For example, the base of pump 22 may be positioned so that its discharge is not received in opening 14A, but is close enough to opening 14A that the operation of the pump raises the level of molten metal in second chamber 18 independent of the level in chamber 16 and causes molten metal to move out of second chamber 18 and into another structure. A sealant, such as cement (which is known to those skilled in the art), may be used to seal base 32 into opening 14A, although it is preferred that a sealant not be used.

[0043] Once pump 22 is turned off, the respective levels of molten metal level in chambers 16 and 18 essentially equalize. Alternatively, the speed of pump 22 could be reduced to a relatively low speed to keep the level of molten metal in second chamber 18 relatively constant but not exceed height H2. To move molten metal onto raised surface 20, pump 22 is simply turned on again and operated as described above.

[0044] A system according to this disclosure could also include one or more pumps in addition to pump 22, in which case the additional pump(s) may circulate molten metal within first chamber 16 and/or second chamber 18, or from chamber 16 to chamber 18, and/or may release gas into the molten metal first in first chamber 16 or second chamber 18. For example, first chamber 16 could include pump 22 and a second pump, such as a circulation pump or gas-release pump, to circulate and/or release gas into molten metal M.

[0045] As shown in FIGS. 1-3A, launder 20 is any structure or device for transferring molten metal to one or more structures, such as one or more ladles, molds (such as ingot molds) or other structures in which the molten metal is ultimately cast into a usable form, such as an ingot. Launder 20 may be either an open or enclosed channel, trough or conduit and may be of any suitable dimension or length, such as one to four feet long, or as much as 100 feet long or longer. Launder 20 may be completely horizontal or may slope gently upward or downward. Launder 20 may have one or more taps (not shown), i.e., small openings stopped by removable plugs. Each tap, when unstopped, allows molten metal to flow through the tap into a ladle, ingot mold, or other structure. Launder 20 may additionally or alternatively be serviced by robots or cast machines capable of removing molten metal M from launder 31.

[0046] Launder 20 has a first end 21A and a second end 21B that is opposite first end 21B. An optional stop may be included in a launder according to this disclosure. The stop, if used, is preferably juxtaposed the second end 21B of the launder. If launder 20 has a stop, the stop can be opened to allow molten metal to flow past end 21B, or closed to prevent molten metal from flowing past end 21B. The stop preferably has a height greater than height H1 so that if launder 20 becomes too filled with molten metal, the molten metal would back up inside launder 20, and spill back over dividing wall 14A (over spillway 14B, if used) rather than overflow launder 20.

[0047] Turning now to FIG. 4, disclosed is a launder 1000 that could be used with system 10, or with any suitable molten metal pumping or transfer device or system. Launder 1000 is comprised of a material, such as graphite or ceramic (such as silicon dioxide) and is configured to transfer molten metal from one place to another.

[0048] The launder 1000 has a channel 1002, a first side 1004, a second side 1006, a bottom 1008, a first top surface 1010 juxtaposed side 1004, and a second top surface 1012 juxtaposed side 1006.

[0049] Channel 1002 as shown is v-shaped. It has a top 1002A having first width A, a first angle B, a third angle C, and a bottom 1002B. The first width A may be any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 20%-90% of the entire width of launder 1000.

[0050] The depth D of channel 1002 as measured from top surface 1012 or 1010 to bottom 1002B is any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 25%-90% of the height of launder 1000 measured along either first side 1004 or second side 1006.

[0051] Angle B is any suitable angle and is preferably from 30-60, or 20-70, or 40-50, or 45, or any amount from 20%-70%. Angle C is any suitable angle and is preferably from 30-60, or any amount from 20-70, or 40-50, or 45.

[0052] As shown in FIG. 5, launder 1020 is the same as launder 1000 except that it has a channel 1022 with a U-shaped bottom portion. Channel 1022 has a top opening 1022A with a first width A, which may be any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 20%-90% of the entire width of launder 1020. The depth D of channel 1022 as measured from top surface 1032 or 1030 to bottom 1028 is any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 20%-90% of the height of launder 1020 measured along either first side 1024 or second side 1026.

[0053] As shown in FIG. 6, launder 1050 has two channels 1052 and 1072. The launder 1050 has a first side 1054, a second side 1056, a bottom 1056, a first top surface 1060 juxtaposed side 1050, a second top surface 1062 juxtaposed side 1056, and a center top surface 1064.

[0054] Each channel 1052 and 1072 as shown is v-shaped. Channel 1052 has a top 1052A having a first width I, a first angle E, a third angle F, and a bottom 1052B. The first width I may be any suitable amount, such as 10%-20%, 10%-30%, 20%-30%, 20%-40%, 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or any amount from 20%-50%, of the entire width of launder 1050.

[0055] The depth K of channel 1052 as measured from top surface 1062, 1064, or 1060 to bottom 1058 is any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 20%-90% of the height of launder 1050 measured along either first side 1054 or second side 1054.

[0056] Channel 1072 has a top 1072A having a first width J, a first angle G, a third angle H, and a bottom 1072B. The first width J may be any suitable amount, such as 10%-20%, 10%-30%, 20%-30%, 20%-40%, 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or any amount from 20%-50%, of the entire width of launder 1050.

[0057] The depth K of channel 1072 as measured from top surface 1062, 1064, or 1060 to bottom 1058 is any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 20%-90% of the height of launder 1050 measured along either first side 1054 or second side 1054.

[0058] Channels 1052 and 1072 need not have the same width or depth.

[0059] Angle E is any suitable angle and is preferably from 30-60, or 20-70, or 40-50, or 45, or 55-70. Angle F is any suitable angle and is preferably from 30-60, or 20-70, or 40-50, or 45, or 55-70, or any amount from 30%-70%. Angle G is any suitable angle and is preferably from 30-60, or 20-70, or 40-50, or 45, or 55-70, or any amount from 30%-70%. Angle H is any suitable angle and is preferably from 30-60, or 20-70, or 40-50, or 45, or 55-70, or any amount from 30%-70%.

[0060] As shown in FIG. 7, launder 1080 is the same as launder 1050 except that it has channels 1082 and 1102, each having U-shaped bottom portions 1082B, 1102B. Channel 1082 has a top 1082A with a first width L, which may be any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or 20%-30%, or any amount from 30%-50% of the entire width of launder 1080. The depth N of channel 1082 as measured from top surface 1090, 1092, or 1094 to bottom 1088 is any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 20%-90% of the height of launder 1080 measured along either first side 1084 or second side 1086.

[0061] Channel 1102 has a top 1102A with a first width M, which may be any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or 20%-30%, or any amount from 20%-50% of the entire width of launder 1080. The depth N of channel 1102 as measured from top surface 1090, 1092, or 1094 to bottom 1088 is any suitable amount, such as 50%-75%, or 60%-90%, or 50%-90%, or 50% or more, or 20%-50%, or any amount from 20%-90% of the height of launder 1080 measured along either first side 1084 or second side 1086.

[0062] Channels 1082 and 1102 need not have the same width or depth.

[0063] Some non-limiting examples of this disclosure are as follow:

[0064] Example 1: A launder for use in moving molten metal, the launder comprising:

[0065] (a) graphite or ceramic;

[0066] (b) at least one channel configured to transfer molten metal, the channel having an upper cross-sectional area and a lower cross-sectional area, the lower cross-sectional area being smaller than the upper cross-sectional area.

[0067] Example 2: The launder of example 1, wherein the channel is V-shaped.

[0068] Example 3: The launder of example 1, wherein the channel is U-shaped.

[0069] Example 4: The launder of example 1 that is comprised of ceramic.

[0070] Example 5: The launder of any of examples 1-4, wherein the channel is centered in the launder.

[0071] Example 6: The launder of any of examples 1-5, wherein the top of the channel has a channel width and top of launder has a launder width, and the channel width is 50% or more of the launder width.

[0072] Example 7: The launder of any of examples 1-5, wherein the top of the channel has a channel width and top of launder has a launder width, and the channel width is 50% or less of the launder width.

[0073] Example 8: The launder of example 1 that has a plurality of channels.

[0074] Example 9: The launder of example 8, wherein each of the plurality of channels is V-shaped.

[0075] Example 10: The launder of any of examples 1-7 that further includes a launder height and a channel height and the channel height is 50% or more of the launder height.

[0076] Example 11: The launder of any of examples 1-7 that further includes a launder height and a channel height and the channel height is 50% or less of the launder height.

[0077] Example 12: The launder of example 2, wherein each side of the V-shaped launder is formed at an angle of 30 degrees-60 degrees from the horizontal axis.

[0078] Example 13: The launder of example 2, wherein each side of the V-shaped launder is formed at an angle of 45 degrees from the horizontal axis.

[0079] Having thus described different embodiments of the invention, other variations and embodiments that do not depart from the spirit of the invention will become apparent to those skilled in the art. The scope of the present invention is thus not limited to any particular embodiment, but is instead set forth in the appended claims and the legal equivalents thereof. Unless expressly stated in the written description or claims, the steps of any method recited in the claims may be performed in any order capable of yielding the desired product.