WO2020231856A1 - Système de transfert de tourbillon de débordement muni de déflecteurs - Google Patents

Système de transfert de tourbillon de débordement muni de déflecteurs Download PDF

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Publication number
WO2020231856A1
WO2020231856A1 PCT/US2020/032213 US2020032213W WO2020231856A1 WO 2020231856 A1 WO2020231856 A1 WO 2020231856A1 US 2020032213 W US2020032213 W US 2020032213W WO 2020231856 A1 WO2020231856 A1 WO 2020231856A1
Authority
WO
WIPO (PCT)
Prior art keywords
molten metal
baffle
pump
inlet
baffles
Prior art date
Application number
PCT/US2020/032213
Other languages
English (en)
Inventor
Jason Tetkoskie
David SCHLICHT
Alan Matthews
Original Assignee
Pyrotek, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pyrotek, Inc. filed Critical Pyrotek, Inc.
Publication of WO2020231856A1 publication Critical patent/WO2020231856A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
    • F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
    • F04D7/06—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being hot or corrosive, e.g. liquid metals
    • F04D7/065—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being hot or corrosive, e.g. liquid metals for liquid metal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/70—Suction grids; Strainers; Dust separation; Cleaning
    • F04D29/708—Suction grids; Strainers; Dust separation; Cleaning specially for liquid pumps

Definitions

  • Pumps for pumping molten metal are used in furnaces in the production of metal articles. Common functions of pumps are circulation of molten metal in the furnace or transfer of molten metal to remote locations along transfer conduits or risers that extend from a base of the pump to the remote location.
  • a transfer pump is located in a separate well adjacent to the main hearth.
  • the transfer pump draws molten metal from the well in which it resides and transfers it into a ladle or conduit and from there to die casters that form the metal articles.
  • the present invention relates to pumps used to transfer molten metal from a furnace to a die casting machine, ingot mould, DC caster or the like.
  • the molten metal pump is indicated generally by the reference numeral 10.
  • the pump 10 is adapted to be immersed in molten metal contained within a vessel 12.
  • the vessel 12 can be any container containing molten metal, although the vessel 12 as illustrated is an external well of a reverberatory furnace 13.
  • the pump 10 has a base member 14 within which an impeller (not shown) is disposed.
  • the impeller includes an opening along its bottom or top surface that defines a fluid inlet for the pump 10.
  • the impeller is supported for rotation within the base member 14 by means of an elongate, rotatable shaft 18.
  • the upper end of the shaft 18 is connected to a motor 20.
  • the base member 14 includes an outlet passageway connected to a riser 24.
  • a flanged pipe 26 is connected to the upper end of the riser 24 for discharging molten metal into a spout or other conduit (not shown).
  • the pump 10 thus described is so-called transfer pump, that is, it transfers molten metal from the vessel 12 to a location outside of the vessel 12.
  • transfer pump is so-called transfer pump, that is, it transfers molten metal from the vessel 12 to a location outside of the vessel 12.
  • Another exemplary transfer pump is described in CA 2284985.
  • the pump consists of two main parts, an upper tube portion which is suspended above the molten magnesium bath during operation and lower tube portion which is immersed in the bath.
  • a motor is positioned at the top of the upper portion.
  • a coupling attaches an auger shaft to the motor.
  • the coupling holds the weight of the auger shaft and positions it in place inside the tube.
  • the auger shaft is centered within the internal diameter of the two portions, running the length of both, and is held in position by a set of guide bearings.
  • the lower portion is comprised of a cylindrical casing in which the auger is located and aligned.
  • Several inlet holes are located in the walls of the cylindrical casing.
  • a second set of inlet holes in the cylindrical casing are located near the base of the pump. These inlet holes permit the surrounding molten metal to enter the pump.
  • the auger comprises a shaft, upon which are welded flutes.
  • the pitch of the flutes preferably varies between 2 to 4 inches.
  • the auger acts like a positive displacement pump.
  • the rotation of the auger shaft by the motor supplies a steady force to the molten magnesium, forcing the molten liquid to the bottom of the pump and out of an elbow shaped connector located at the outlet end of the cylindrical casing at the base of the pump.
  • the molten magnesium displaced to the bottom of the pump is downwardly forced out through the connector by means of the rotation of the auger.
  • the connector is attached to a heated transfer tube which will convey the molten magnesium from the holding furnace to the die of a casting machine.
  • a further alternative transfer pump is described in U.S. Published Application 2008/0314548.
  • the system comprises at least (1) a vessel for retaining molten metal, (2) a dividing wall (or overflow wall) within the vessel, the dividing wall having a height H1 and dividing the vessel into a least a first chamber and a second chamber, and (3) a molten metal pump in the vessel, preferably in the first chamber.
  • the second chamber has a wall or opening with a height H2 that is lower than height H1 and the second chamber is juxtaposed another structure, such as a ladle or lauder, into which it is desired to transfer molten metal from the vessel.
  • the pump (either a transfer, circulation or gas-release pump) is submerged in the first chamber (preferably) and pumps molten metal from the first chamber past the dividing wall and into the second chamber causing the level of molten metal in the second chamber to rise.
  • molten metal flows out of the second chamber and into another structure.
  • a circulation pump which is most preferred, or a gas-release pump were utilized, the molten metal would be pumped through the pump discharge and through an opening in the dividing wall wherein the opening is preferably completely below the surface of the molten metal in the first chamber.
  • a molten metal pump comprising an elongated tube having a base end and a top end.
  • a shaft extends into the tube and rotates an impeller proximate the base end.
  • the elongated tube includes at least baffle one disposed about the base end, wherein the at least one baffle is configured to impede the formation of a vortex about an inlet of the base end.
  • the tube has a diameter at least 1.1 times the diameter of the impeller.
  • the tube has a length of at least three times the height of the impeller.
  • the base end includes an inlet and the top end includes an outlet.
  • a molten metal pump comprised of an elongated refractory body.
  • the refractory body includes an inlet region having an inlet region diameter, a vortex region having a vortex region diameter, and an outlet region having an outlet region diameter.
  • the molten metal pump also includes at least one baffle positioned about the inlet end of the refractory body and is configured to impede the formation of a vortex in the molten metal during pumping.
  • the outlet region diameter is greater than the vortex region diameter which is greater than the inlet region diameter.
  • An impeller is disposed in or adjacent the inlet.
  • a shaft extends through the vortex region and the outlet region and includes a first end engaging the impeller and a second end adapted to engage a motor.
  • FIGURE 1 is a schematic view of a prior art system including a furnace, a melting bay and an adjacent bay containing a transfer pump;
  • FIGURE 2 is a perspective view showing a molten metal transfer system including the pump disposed in a furnace bay;
  • FIGURE 3 is a perspective partially in cross-section view of the system of Figure 2;
  • FIGURE 4 is a side cross-sectional view of the system shown in FIGS. 2 and 3;
  • FIGURE 5 is a perspective view of the pumping chamber
  • FIGURE 6 is a top view of the pumping chamber
  • FIGURE 7 A is a view along the line A— A of FIG. 6;
  • FIGURE 7B is an alternative embodiment of the view along line A-A of FIG.6;
  • FIGURE 7C is an alternative embodiment of the view along line A-A of FIG.6;
  • FIGURE 8 is a perspective view of the impeller top section
  • FIGURE 9 is a perspective view of the assembled impeller
  • FIGURE 10 is an alternative impeller design
  • FIGURE 11 is an exploded view of the impeller of Figure 10;
  • FIGURE 12 is an alternative embodiment with an electric motor
  • FIGURE 13 is a further alternative embodiment with an air motor.
  • the molten metal pump 30 of the present invention is depicted in association with a furnace 28.
  • Pump 30 is suspended via metallic framing 32 which rests on the walls of the furnace bay 34.
  • a motor 35 rotates a shaft 36 and the appended impeller 38.
  • a refractory body 40 forms an elongated generally cylindrical pump chamber or tube 41.
  • the refractory body can be formed, for example, from fused silica, silicon carbide or combinations thereof.
  • Body 40 includes an inlet 43 located on the base end 46 which receives impeller 38.
  • bearing rings 45 are provided to facilitate even wear and rotation of the impeller 38 therein.
  • molten metal is drawn into the impeller through the inlet (arrows) and forced upwardly within tube 41 from the base end 46 in the shape of a forced (“equilibrium”) vortex.
  • a volute shaped chamber 42 is provided to direct the molten metal vortex created by rotation of the impeller outwardly into trough 44.
  • Trough 44 can be joined/mated with additional trough members or tubing to direct the molten metal to its desired location such as a casting apparatus, a ladle or other mechanism as known to those skilled in the art.
  • the base of the tube may be formed into a general bell shape, rather than flat. This design may produce a deeper vortex and allow the device to have improved function as a scrap submergence unit.
  • the body 40 also includes at least one baffle 48.
  • the at least one baffle 48 is positioned about the base end 46.
  • a vortex in the molten metal may form about the base end 46 and inlet 43.
  • the vortex hinders the efficient operation of the pump.
  • the at least one baffle 48 is configured to prevent and hinder the formation of or break the formed vortex at low metal levels within the furnace bay 34. With the vortex broken, hindered, or prevented by the at least one baffle 48, the flow of molten metal through the tube is increased compared to the flow hindered by vortex formation (a pump without baffles).
  • the baffled system also has an increased capability at passing debris in the furnace.
  • the at least one baffle 48 includes a bottom end 49 that extends substantially perpendicular to the base end 46 of the body 40.
  • the at least one baffle 48 also extends radially from the body 40 in a radial direction R and along a bottom portion D of the body 40. It is to be appreciated that the length D is not limiting.
  • the baffle includes a tapered top portion T.
  • the at least one baffle 148 extends substantially perpendicular from the base end 46 of the body 40. In these embodiments, the baffle 48 does not extend radially past an outer circumference of the body 40. In other embodiments, and with reference to Figure 7C, the at least one baffle 248 extends in a radial direction R from the body 40 along a bottom portion D of the body 40. In these embodiments, the baffle 48 does not extend past the base end 46. In yet still other embodiments, the pump 30 may include any combination of the baffles 48, 148, and 248 as described above.
  • the pump system includes at least two baffles.
  • the baffles may be identical or at least one baffle may extend in at least a radial direction from the pump body and at least may baffle extend at least in a direction perpendicular from the base end.
  • a pump system may include a plurality of differently shaped baffles.
  • the body 40 includes a plurality of baffles 48 that are equally spaced about a circumference of the tube body 40. Although four baffles are illustrated, it is to be appreciated the number of baffles 48 is not limiting. That is, the number of baffles 48 may be less than four or greater than four.
  • the at least one baffle 48 is further configured to support the body 40 as a leg. That is, the bottom end 49 of the baffle 48 contacts the bottom surface 33 of the furnace bay 34. In other embodiments and not shown, the at least one baffle 48 is configured such that the bottom end 49 does not touch the bottom surface 33 of the furnace bay 34. Rather, the pump 30 is suspended by frame 32, and the baffles do no provide a support function.
  • the baffles 48 are integrated into the body 40. That is, the baffles 48 and body 40 are formed of one continuous piece of metal or ceramic material.
  • the at least one baffle 48 is permanently attached to the body 40, for example and without limitation, by welding.
  • the at least one baffle may be removably attached to the body 40, for example and without limitation, by at least one fastener (e.g., screws).
  • a plurality of baffles may be in the form of a sleeve that is able to be placed about the base end 46 of the body 40.
  • a sleeve may be a ring configured to engage a circumference of the body 40.
  • the ring includes a plurality of baffles, that when engaged with the body 40, extended in either or both a radial direction and direction perpendicular to the base end 46.
  • Figure 5 shows a perspective view of the refractory body 40.
  • Figure 6 shows a top view of the volute design and Figures 7A-C cross-sectional views of the elongated generally cylindrical pumping chamber. These views show the general design parameters where the tube 41 is at least 1.1 times greater in diameter, preferably at least about 1.5 times, and most preferably, at least about 2.0 times greater than the impeller diameter. However, for higher density metals, such as zinc, it may be desirable that the impeller diameter relative to pumping chamber diameter be at the lower range of 1.1 to 1.3. In addition, it can be seen that the tube 41 is significantly greater in length than the impeller is in height.
  • the tube length (height) is at least three times, more preferably at least 10 times, greater than a height of the impeller. Without being bound by theory, it is believed that these dimensions facilitate formation of a desirable forced (“equilibrium”) vortex of molten metal as shown by line 47 in Figure 7A-C.
  • FIGs 8 and 9 depict the impeller 38 which includes top section 37 having vanes 39 supplying the induced molten metal flow and a hub 50 for mating with the shaft 36.
  • impeller 38 In its assembled condition, impeller 38 is mated via screws or bolts to an inlet guide section 52 having a hollow central portion 54 and bearing rings 56.
  • the impeller can be constructed of graphite or other suitable refractory material. It is envisioned that any traditional molten metal impeller design would be functional in the present overflow vortex transfer system.
  • the impeller top section 62 includes bores 64 in the vanes 65 which receive posts 66 to facilitate proper registration of the components and increase the mating strength.
  • the inlet guide section 68 has been extended relative to the prior design to include bearing rings 56 and added alignment element 70. Particularly, alignment element 70 is received within a the cooperatively shaped inlet 43.
  • the pump assembly 100 has a metal frame 101 surrounding the top portion 127 (outlet chamber) of the refractory tube 41 and includes a motor mount 102 which is secured to the pump assembly 100.
  • the motor mount assembly 102 is secured to together via hex bolts 103, flat washers 104, lock washers 105 and hex nut 106.
  • Motor adaptor assembly 107 joins electric motor 108 to the motor mount 102.
  • hex bolts 109, lock washers 110, hex nuts 111 provide the mating between electric motor adaptor assembly 107 and electric motor 108.
  • a hanger 112 is provided to facilitate the lifting of the assembly.
  • Hanger 112 is secured to the motor via hex bolts 113 and flat washers 114.
  • Heat break coupling assembly 115 mates the motor drive shaft to the shaft and impeller assembly 116.
  • a mounting support assembly 117 including hex bolts 118, bevel washer 119 and hex nut 120 is provided to secure the assembly to the furnace.
  • a strainer 121 or a filter cap 122 are provided to protect against ingress of unwanted debris into the pump.
  • the filter cap 122 may include at least one baffle (similar to baffle 48 as described above in relation to the body 40). The at least one baffle 48 is configured to impede the formation of vortices about the end 146.
  • a compressible fiber blank can be disposed between the steel frame and the refractory bowl to accommodate variations in thermal expansion rates.
  • the outlet chamber is provided with an overflow notch 123 to safely return molten metal to the furnace in the event of a downstream obstruction which blocks primary outlet trough 124.
  • Overflow notch 123 has a shallower depth than primary outlet trough 124.
  • Air motor 208 includes a muffler 209 and is secured to the air motor adapter assembly 207 via hex bolts 210, and lock washers 211.
  • a heat break coupling 212 mates the drive shaft of the air motor 207 to shaft and impeller assembly 213.
  • Mounting support assembly 214 is provided to secure the unit to the refractory furnace. Particularly, hex bolts 215, bevel washers 216 and hex nuts 217 provide securement thereof.
  • strainer 218 or filter cap 219 are provided.
  • the filter cap 219 may include at least one baffle (similar to baffle 48 as described above in relation to the body 40). The at least one baffle is configured to impede the formation of vortices about the base end 246.
  • the invention has many advantages in that its design creates an equilibrium vortex at a low impeller RPM, creating a smooth surface with little to no air intake. Accordingly, the vortex is non-violent and creates little or no dross. Moreover, the present pump creates a forced vortex within the body 40 having a constant angular velocity such that the column of rotating molten metal rotates as a solid body having very little turbulence.
  • the pump has excellent flow tunability, its open design structure provides for simple and easily cleaning access. Advantageously, only shaft and impeller replacement parts will generally be required. In fact, the pump is generally self-cleaning wherein dross formation in the riser is eliminated because the metal level is high. Generally, a lower torque motor, such as an air motor, will be sufficient because of the low torque experienced.
  • Optional additions to the design include the location of a filter at the base of the inlet of the pumping chamber. It is further envisioned that the pump would be suitable for use in molten zinc environments where a very long, pull (e.g. 14 ft.) is required. Such a design may preferably include the addition of a bearing mechanism at a location on the rotating shaft intermediate the motor and impeller. Furthermore, in a zinc application, the entire construction could be manufactured from metal, such as steel or stainless steel, including the pumping chamber tube, and optionally the shaft and impeller.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

L'invention concerne une pompe à métal en fusion comprenant un tube de chambre de pompage allongé doté d'une extrémité de base et d'une extrémité supérieure ouverte. Un arbre s'étend dans le tube et fait tourner une turbine à l'intérieur, la turbine tournant à proximité de l'extrémité de base. Le diamètre du tube représente au moins 1,1 fois le diamètre de la turbine. L'extrémité de base comprend une entrée et l'extrémité supérieure comprend une sortie tangentielle. Au moins un déflecteur est placé autour de l'extrémité de base, le déflecteur étant conçu pour empêcher la formation d'un tourbillon dans le métal fondu pendant le pompage.
PCT/US2020/032213 2019-05-10 2020-05-08 Système de transfert de tourbillon de débordement muni de déflecteurs WO2020231856A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201962846450P 2019-05-10 2019-05-10
US62/846,450 2019-05-10

Publications (1)

Publication Number Publication Date
WO2020231856A1 true WO2020231856A1 (fr) 2020-11-19

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1309245A (zh) * 2000-02-02 2001-08-22 株式会社荏原制作所 泵中的防涡流装置
JP2001329987A (ja) * 2000-05-19 2001-11-30 Mazda Pomp Manufacturing Co Ltd 溶融金属用竪型沈下式軸流ポンプ
US6439860B1 (en) * 1999-11-22 2002-08-27 Karl Greer Chambered vane impeller molten metal pump
US20130101424A1 (en) * 2009-06-16 2013-04-25 Mark A. Bright Overflow vortex transfer system
EP2778422A1 (fr) * 2011-11-10 2014-09-17 Hitachi, Ltd. Pompe à baril de fosse et procédé permettant d'incorporer ladite pompe

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6439860B1 (en) * 1999-11-22 2002-08-27 Karl Greer Chambered vane impeller molten metal pump
CN1309245A (zh) * 2000-02-02 2001-08-22 株式会社荏原制作所 泵中的防涡流装置
JP2001329987A (ja) * 2000-05-19 2001-11-30 Mazda Pomp Manufacturing Co Ltd 溶融金属用竪型沈下式軸流ポンプ
US20130101424A1 (en) * 2009-06-16 2013-04-25 Mark A. Bright Overflow vortex transfer system
EP2778422A1 (fr) * 2011-11-10 2014-09-17 Hitachi, Ltd. Pompe à baril de fosse et procédé permettant d'incorporer ladite pompe

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