Transfer pump launder system

Abstract

A transfer pump system has a pump base with a pump chamber, tangential discharge and an outlet. A riser tube extends from the outlet and terminates at a launder in order to move molten metal out of a vessel with relatively little turbulence. A riser tube for use in the system has a proximal end configured to be connected to the outlet and a distal end that terminates at or above the launder.

Claims

1. A pump configured to be positioned in a vessel that contains molten metal, the pump comprising: (a) a pump base having a pump chamber, a top surface, and a tangential discharge leading to an outlet; (b) a riser tube having a passage therethrough, a proximal end having an opening in communication with the passage, the proximal end physically attached to the outlet, a distal end opposite the proximal end, wherein the distal end has an opening in communication with the passage, the distal end being open; (c) a superstructure above the pump outlet, the riser tube being supported by the superstructure; (d) a launder configured to extend from the vessel to a second vessel, the launder having an open top, and a bottom surface, wherein the distal end of the riser tube is physically connected to the bottom surface of the launder, and the opening in the distal end terminates at or above the bottom surface of the launder and below the open top of the launder, and wherein molten metal can be pumped upward through the riser tube and into the launder; (e) an opening in the bottom surface of the launder, wherein the distal end of the riser tube is received in the opening in the bottom surface of the riser tube; and (f) the distal end of the riser tube has a raised back portion and a front portion being lower than the back portion, wherein molten metal reaching the distal end of the riser tube exits the front portion and enters the launder.

2. The pump of claim 1, wherein the opening in the bottom surface of the launder is circular and the riser tube is cylindrical, and the distal end of the riser tube is received in the circular opening in the bottom surface of the launder.

3. The pump of claim 2, wherein the distal end of the riser tube has a front portion that terminates at or above the bottom surface of the launder, and has a raised back portion opposite the front portion, wherein the back portion extends above the front portion, and, to the open top of the launder or higher wherein molten metal reaching the distal end of the riser tube exits the front portion and enters the launder.

4. The pump of claim 3, wherein the front portion is within 3 above the top surface of the launder.

5. The pump of claim 1, wherein the front portion is at a height between: being even with the top surface of the launder to 3 above the top surface of the launder.

6. The pump of claim 1, wherein the launder tilts backward towards the distal end of the riser tube.

7. The pump of claim 6, wherein the launder has a horizontal angle of 0, or tilts towards the riser tube at a horizontal angle of between 1-5 degrees, or 1-3 degrees.

8. The pump of claim 6, wherein the launder tilts backwards at a slope of for every 10 of launder length.

9. The pump of claim 1 that further includes a motor positioned on the superstructure.

10. The pump of claim 9 that further includes a drive shaft having a first end connected to the motor, and a second end connected to a rotor, wherein the rotor is positioned in the pump chamber.

11. The pump of claim 10, wherein the drive shaft comprises a rotor shaft having an end that is received in a coupling, and a motor shaft having an end that is also received in the coupling.

12. The pump of claim 10, wherein the second end of the rotor shaft is threadingly received in the rotor.

13. The pump of claim 1, wherein the distal end of the riser tube terminates within 3 above the top surface of the launder.

14. The pump of claim 1, wherein the pump base has a side surface and the pump outlet is in the side surface.

15. The pump of claim 14, wherein the proximal end of the riser tube is an extension piece formed as an elbow to direct the flow from the pump outlet upwards.

16. A riser tube for use in a molten metal transfer pump, wherein the molten metal transfer pump includes (i) a pump base having an inlet, a pump casing, and an outlet, and (ii) a superstructure, wherein the riser tube is configured to have a length sufficient to extend from the outlet to a position at which it connects to a launder, the riser tube comprising: (a) a passage therethrough; (b) a proximal end having an opening in communication with the passage, the proximal end configured to be physically attached to the output port; (c) a distal end opposite the proximal end, wherein the distal end has an opening in communication with the passage, the distal end being open; and (d) wherein the distal end of the riser tube has a front portion configured to terminate at or above the bottom surface of a launder, and has a raised back portion opposite the front portion, wherein the raised back portion extends above a height of the front portion.

17. The riser tube of claim 16, wherein the raised back portion is up to 3 higher than the front portion.

18. The riser tube of claim 16 that is supported by the superstructure.

19. The riser tube of claim 16, wherein the distal end is configured to be above the superstructure.

20. The riser tube of claim 16, wherein the proximal end of the riser tube is configured to be connected to the outlet of the pump base.

21. The riser tube of claim 16 that is comprised of graphite.

22. The riser tube of claim 16, wherein the proximal end of the riser tube is an extension piece formed as an elbow and is configured to direct the flow from the pump outlet upwards.

23. The riser tube of claim 16, wherein the distal end of the riser tube is configured to terminate within 3 above the top surface of the launder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a front, partial cross-sectional view of a transfer pump according to an aspect of the invention.

(2) FIG. 2 is a front, partial cross-sectional view of a transfer pump according to an aspect of the invention.

(3) FIG. 3 is a front, partial cross-sectional view of a transfer pump according to an aspect of the invention.

(4) FIG. 4 front, partial cross-sectional view of a transfer pump according to an aspect of the invention.

(5) FIG. 5 is a top view of the riser tube/launder configuration shown in FIG. 1, or in FIG. 2 (with the top wall of launder 1000 removed).

(6) FIG. 6 is a top view of the riser tube/launder configuration of FIG. 3 or FIG. 4 (with the top wall of launder 1000 or 2000, respectively, removed).

(7) FIG. 7 is a partial, cross-sectional view showing the preferred pump base and lower portion of the riser tube of FIGS. 1-4.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

(8) Referring now to the figures, where the purpose is for describing a preferred embodiment of the invention and not for limiting same, FIG. 1 shows a pumping device 10 submerged in a metallic bath B. Device 10 has a superstructure 20 and a base 50. Superstructure 20 is positioned outside of bath B when device 10 is operating and generally comprises a mounting plate 24 that supports a motor mount 26. A motor 28 is mounted to mount 26. Motor 28 is preferably electric or pneumatic although, as used herein, the term motor refers to any device capable of driving a rotor 70.

(9) Superstructure 20 is connected to base 50 by one or more support posts 30. Preferably posts 30 extend through openings (not shown) in plate 24 and are secured by post clamps 32, which are preferably bolted to the top surface (preferred) or lower surface of plate 24.

(10) A motor drive shaft 36 extends from motor 28. A coupling 38 has a first coupling member 100, attached to drive shaft 36, and a second coupling member 180, attached to a rotor shaft 40. Motor drive shaft 36 drives coupling 38 which, in turn, drives rotor shaft 40. Preferably neither coupling 38 nor shaft 40 have any connecting threads, although any suitable coupling may be used.

(11) Base 50 is preferably formed from graphite or other suitable material. Base 50 includes a top surface 54 and an input port 56, preferably formed in top surface 54. A pump chamber 58, which is in communication with port 56, is a cavity formed within housing 50. A discharge 60, shown in FIG. 7, is preferably formed tangentially with, and is in fluid communication with, pump chamber 58. Discharge 60 leads to an output port 62, shown in FIG. 7 as being formed in a side surface of housing 50. A wear ring or bearing ring 64 is preferably made of ceramic and is cemented to the lower edge of chamber 58. Device 10 incorporates a metal-transfer conduit, or riser tube, 300 connected to output port 62. Conduit 300 is normally used in conjunction with an elbow to transfer the pumped molten metal into another molten metal bath, but as described herein instead connects to a launder 1000.

(12) As shown in FIG. 1, rotor 70 is attached to and driven by shaft 40. Rotor 70 is preferably placed centrally within chamber 58, and may be of any suitable design. Rotor 70 is preferably imperforate, being formed of solid graphite or graphite and ceramic.

(13) Rotor 70 further includes a connective portion 74, which is preferably a threaded bore, but can be any structure capable of drivingly engaging rotor shaft 40. A flow blocking plate 78 is preferably formed of ceramic and is cemented to the base of rotor 70. Plate 78 rides against bearing ring 64 and blocks molten metal from entering or exiting through the bottom of chamber 58. Alternatively, the bearing ring could be eliminated, in which case there would be a second input port.

(14) Coupling 38 generally comprises a first coupling member 100, a disk 150 and a second coupling member 180. First coupling member 100 is preferably formed of metal, and most preferably steel, and is dimensioned to receive an end of motor drive shaft 36.

(15) Second coupling member 180 is designed to receive and drive rotor shaft 40. Member 180 is preferably formed of metal such as steel or aluminum although other materials may be used.

(16) As shown, pumping device 10 is a transfer pump, in which case it will include transfer pump base 50 as shown, or any other suitable base. As previously described, and as shown in FIG. 1, base 50 includes an upper surface 54 and a discharge 60 leading to an output port 62, which is formed in a side of base 50 (as used herein, the term discharge refers to the passageway leading from the pump chamber to the output port, and the output port is the actual opening in the exterior surface of the pump base). In this embodiment, an extension piece 11 is attached to output port 62 and defines a passageway formed as an elbow so as to direct the flow of the pumped molten metal upward. A metal-transfer conduit 300 is connected to extension member 11 and can be secured by being cemented thereto.

(17) The invention does not include a U-shape at the distal, or top, end of the riser tube 300 so that molten metal is released from the end and splashes into another structure or vessel. Instead molten metal is pushed to the top of the riser tube and enters a launder 1000. This avoids splashing and dross formation.

(18) FIG. 1 shows an embodiment where riser tube 300 terminates at distal end 301 and distal end 301 has a raised back portion 301A and a lower front portion 301B that is inside the launder 1000. Riser tube 300 is supported by the superstructure 20. A top view of such a structure is shown in FIG. 5 with the arrow denoting the flow of molten metal through the launder 1000. This same structure of the distal end 301 could be entirely inside of the launder 1000, and such a structure is shown in FIG. 6 (and FIGS. 3-4) with the arrow again denoting the fluid flow direction.

(19) FIG. 2 shows a riser tube 300 that is integrally connected with a launder 1000.

(20) FIG. 3 shows a side view of a riser tube 300 having a distal end 300 that is entirely inside of riser tube 1000, and a top view of such a structure is shown in FIG. 6. End 301 has a raised back portion 301A and a lower front portion 301B, so molten metal is moved in the direction indicated by the arrow in FIG. 6.

(21) FIG. 4 shows a side view of a transfer pump with a riser tube 3000 that terminates at distal end 3001 inside of a launder 2000. In this embodiment, launder 2000 has a closed back end 2001 and molten metal enters the launder and fills it so the molten metal flows in the direction shown by the arrow in FIG. 6.

(22) A launder used in the practice of the invention may be sloped downward, but is preferably horizontal or sloped upward so the flow of molten metal moves back towards the distal end of the riser tube when the pump is turned off and there is no pressure to push molten metal through the launder. A preferred upward slope is 1-10, or 1-5, or 1-3, or an upward slope of for every 10 of launder length.

(23) Having thus described some 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 result.