CA2284985C - Auger pump for handling magnesium and magnesium alloys - Google Patents
Auger pump for handling magnesium and magnesium alloys Download PDFInfo
- Publication number
- CA2284985C CA2284985C CA 2284985 CA2284985A CA2284985C CA 2284985 C CA2284985 C CA 2284985C CA 2284985 CA2284985 CA 2284985 CA 2284985 A CA2284985 A CA 2284985A CA 2284985 C CA2284985 C CA 2284985C
- Authority
- CA
- Canada
- Prior art keywords
- pump
- molten metal
- auger
- casing
- transfer tube
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired - Fee Related
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- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 title abstract description 33
- 229910052749 magnesium Inorganic materials 0.000 title abstract description 32
- 239000011777 magnesium Substances 0.000 title abstract description 32
- 229910000861 Mg alloy Inorganic materials 0.000 title 1
- 229910052751 metal Inorganic materials 0.000 claims description 58
- 239000002184 metal Substances 0.000 claims description 58
- 239000000155 melt Substances 0.000 claims description 14
- 230000008878 coupling Effects 0.000 claims description 4
- 238000010168 coupling process Methods 0.000 claims description 4
- 238000005859 coupling reaction Methods 0.000 claims description 4
- 230000001681 protective effect Effects 0.000 claims description 4
- 238000004512 die casting Methods 0.000 abstract description 8
- 229910045601 alloy Inorganic materials 0.000 abstract description 5
- 239000000956 alloy Substances 0.000 abstract description 5
- 238000005086 pumping Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 9
- 238000006073 displacement reaction Methods 0.000 description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 238000013019 agitation Methods 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000005266 casting Methods 0.000 description 4
- QHMQWEPBXSHHLH-UHFFFAOYSA-N sulfur tetrafluoride Chemical compound FS(F)(F)F QHMQWEPBXSHHLH-UHFFFAOYSA-N 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 3
- 230000006698 induction Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
- B22D21/002—Castings of light metals
- B22D21/007—Castings of light metals with low melting point, e.g. Al 659 degrees C, Mg 650 degrees C
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/20—Accessories: Details
- B22D17/30—Accessories for supplying molten metal, e.g. in rations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D39/00—Equipment for supplying molten metal in rations
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D3/14—Charging or discharging liquid or molten material
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
- C22B26/20—Obtaining alkaline earth metals or magnesium
- C22B26/22—Obtaining magnesium
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D2003/0034—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities
- F27D2003/0054—Means to move molten metal, e.g. electromagnetic pump
- F27D2003/0055—Means to move molten metal, e.g. electromagnetic pump with flow regulation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27M—INDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
- F27M2001/00—Composition, conformation or state of the charge
- F27M2001/01—Charges containing mainly non-ferrous metals
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Furnace Charging Or Discharging (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
An auger pump for pumping molten magnesium and its alloys from a furnace to a die casting machine, ingot mould, DC caster or the like is disclosed. The pump is comprised of a linearly aligned upper and lower portion. The upper portion is comprised of a housing which is attached to the furnace lid. An inverter duty electric motor is attached to the top of the housing and is controlled by a PLC. The auger shaft runs longitudinally between each portion and is supported in position by guide bearings located in the upper portion. The lower portion comprises a tubular casing which contains a gas inlet aperture and an feeder inlet aperture for drawing the molten magnesium into the pump.
The outlet of the pump, a connector, is attached to a heated transfer tube, which conveys the molten magnesium to the mould.
The outlet of the pump, a connector, is attached to a heated transfer tube, which conveys the molten magnesium to the mould.
Description
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to pumps used to transfer measured quantities of molten metal from a furnace to a die casting machine, ingot mould, DC caster or the like. In particular, the present invention relates to positive displacement pumps which are used with high melting point metals such as molten magnesium and its alloys.
1. FIELD OF THE INVENTION
The present invention relates to pumps used to transfer measured quantities of molten metal from a furnace to a die casting machine, ingot mould, DC caster or the like. In particular, the present invention relates to positive displacement pumps which are used with high melting point metals such as molten magnesium and its alloys.
2. PRIOR ART
There has been a steady increase in the use of magnesium and its alloys in the die casting industry especially as it relates to the automotive manufacturing sector. An explanation for the increase is that castings made of magnesium, in comparison to steel and aluminum, are lightweight but have equal or superior strength characteristics.
Special precautions and handling requirements must be taken with molten magnesium (which term shall be used hereinafter to include its alloys). The molten metal is highly volatile and burns when exposed to the atmosphere requiring the use of inert gases such as Argon or toxic gases such as sulfur tetrafluoride (SF6) and sulfur dioxide (SOz) to eliminate burning. The high melting point of magnesium also poses special considerations in designing a reliable pump.
There are various types of pumps available for delivering measured quantities of molten metal to die casting machines. Gas displacement, electromagnetic, centrifugal and positive displacement pumps are the general types of pumps used in the industry. The die casting machine receives a measured quantity of molten metal known as a shot which is used to make a casting. Both the quantity or metal delivered and the reliability of the delivery mechanism as described hereinafter are most important for reliable manufacturing casting operations.
Typically, the pump operates in conjunction with a transfer tube to deliver a shot to the die casting machine. As such the pump transfers a quantity of molten metal from the magnesium melt furnace into the tube for delivery to the die.
Gas displacement pumps use gas pressure to displace molten metal from a sealed vessel into a heated transfer tube which is submerged in the molten metal. Typically an inert gas is used to displace the molten magnesium through the transfer tube.
However, this arrangement does not deliver sufficiently accurate shots. One reason for this is that the gas medium used to displace the molten metal by means of compression itself depends on temperature for its compression efficiency. As well, over time build up of magnesium occurs inside the tube creating increased resistance to the movement of molten magnesium through it. In addition, these pumps contain internal valves that are prone to clogging and are difficult to replace.
Electromagnetic pumps such as helical magnetic pumps, centrifugal electromagnetic pumps, flat linear induction pumps, and annular linear induction pumps use a magnetic force to induce current flow in a conducting fluid. The reaction to the flux causes a force to be exerted on the fluid so that pumping action takes place. Such pumps have no moving parts and can usefully transfer large volumes of metal but they are also inefficient and expensive.
For example, US Patent 5,407,000 to Mercer, II et al., discloses the use of an annular linear induction electromagnetic pump as part of a method and apparatus for handling molten metals. This pump is expensive and its accuracy depends on the viscosity of the molten metal which is variable. Temperature changes in the holding furnace affects the viscosity of the molten metal and ultimately, the size of the shots.
Centrifugal pumps comprise a cylinder with an internal rotating impeller which produces the necessary head pressure. Such pumps are typically used for transferring large quantities of molten metal but are incapable of delivering accurate small quantity shots.
Positive displacement pumps typically use a piston or plunger to displace and move the molten metal. One problem with this arrangement is that molten metal enters the space between the piston and the containing wall contributing to the clogging and unserviceability associated with this type of pump.
As well, most of the above mentioned pumps contain valves, guides and bearings which come in contact with the molten metal leaving them prone to failure and damage.
There has been a steady increase in the use of magnesium and its alloys in the die casting industry especially as it relates to the automotive manufacturing sector. An explanation for the increase is that castings made of magnesium, in comparison to steel and aluminum, are lightweight but have equal or superior strength characteristics.
Special precautions and handling requirements must be taken with molten magnesium (which term shall be used hereinafter to include its alloys). The molten metal is highly volatile and burns when exposed to the atmosphere requiring the use of inert gases such as Argon or toxic gases such as sulfur tetrafluoride (SF6) and sulfur dioxide (SOz) to eliminate burning. The high melting point of magnesium also poses special considerations in designing a reliable pump.
There are various types of pumps available for delivering measured quantities of molten metal to die casting machines. Gas displacement, electromagnetic, centrifugal and positive displacement pumps are the general types of pumps used in the industry. The die casting machine receives a measured quantity of molten metal known as a shot which is used to make a casting. Both the quantity or metal delivered and the reliability of the delivery mechanism as described hereinafter are most important for reliable manufacturing casting operations.
Typically, the pump operates in conjunction with a transfer tube to deliver a shot to the die casting machine. As such the pump transfers a quantity of molten metal from the magnesium melt furnace into the tube for delivery to the die.
Gas displacement pumps use gas pressure to displace molten metal from a sealed vessel into a heated transfer tube which is submerged in the molten metal. Typically an inert gas is used to displace the molten magnesium through the transfer tube.
However, this arrangement does not deliver sufficiently accurate shots. One reason for this is that the gas medium used to displace the molten metal by means of compression itself depends on temperature for its compression efficiency. As well, over time build up of magnesium occurs inside the tube creating increased resistance to the movement of molten magnesium through it. In addition, these pumps contain internal valves that are prone to clogging and are difficult to replace.
Electromagnetic pumps such as helical magnetic pumps, centrifugal electromagnetic pumps, flat linear induction pumps, and annular linear induction pumps use a magnetic force to induce current flow in a conducting fluid. The reaction to the flux causes a force to be exerted on the fluid so that pumping action takes place. Such pumps have no moving parts and can usefully transfer large volumes of metal but they are also inefficient and expensive.
For example, US Patent 5,407,000 to Mercer, II et al., discloses the use of an annular linear induction electromagnetic pump as part of a method and apparatus for handling molten metals. This pump is expensive and its accuracy depends on the viscosity of the molten metal which is variable. Temperature changes in the holding furnace affects the viscosity of the molten metal and ultimately, the size of the shots.
Centrifugal pumps comprise a cylinder with an internal rotating impeller which produces the necessary head pressure. Such pumps are typically used for transferring large quantities of molten metal but are incapable of delivering accurate small quantity shots.
Positive displacement pumps typically use a piston or plunger to displace and move the molten metal. One problem with this arrangement is that molten metal enters the space between the piston and the containing wall contributing to the clogging and unserviceability associated with this type of pump.
As well, most of the above mentioned pumps contain valves, guides and bearings which come in contact with the molten metal leaving them prone to failure and damage.
BRIEF SUMMARY OF THE INVENTION
An object of this invention is provide a pump for transferring molten magnesium to a die casting machine that is simple in construction, effective, easy to use and maintain, and is relatively inexpensive to manufacture.
A further object of the invention is to provide a pump which does not have any valves, guides, bearings or the like, in contact with molten magnesium, thus making the pump less vulnerable to failure and more reliable.
A further object of the invention is to provide a pump which constantly agitates the molten metal in the magnesium melt furnace. The agitation assists in keeping a constant bath temperature in the furnace when ingots are introduced into the bath.
Maintaining a constant temperature in the bath improves consistency and aids in preventing the premature release and deposits of magnesium metal alloys.
Agitation in the molten bath also assists in stabilizing the viscosity of the molten metal.
Maintaining a consistent viscosity improves both pour speed and pour. Pour time relates to the amount of time required for the pump to change from idle to pour speed.
The agitation is achieved by the auger which continues to rotate at idle speed to maintain a head in the transfer tube as described hereinafter. Naturally, at pour speed, the agitation is further increased. The agitation stabilizes the bath's temperature quickly, substantially reducing the amounts of alloy deposits and variations in viscosity.
There is provided a molten metal pump for transferring metal from a melt furnace by means of a transfer tube, the pump comprising upper and lower aligned portions, the upper portion comprising a frame housing for attachment to the melt furnace and an inverter duty electric motor mounted to the frame housing, the lower portion attached to the upper portion and immersable into the melt furnace, the lower portion comprising a cylindrical casing having an opening at a bottom thereof, a transfer tube connected at one end to the opening, and an auger within the casing connected to the inverter duty electric motor by means of a shaft, the opening being located lower than a bottom flute of the auger, the motor being operable at a first speed to rotate the shaft to transfer molten metal downwardly into the transfer tube in order to maintain a predetermined head within the tube and being further operable at a second speed to transfer a measured quantity of molten metal from the tube.
There is further provided a pump for transferring a molten metal from a melt furnace, the pump comprising: a variable speed motor; a frame housing with means for attaching the pump to the melt furnace; means for mounting the motor to the frame housing; a transfer tube comprising an elbow shaped connector and a vertical portion for maintaining a predetermined head level of the molten metal; a cylindrical casing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the casing at a bottom thereof connecting an interior of the casing to the elbow shaped connector of the transfer tube, and one or more second openings for admitting the molten metal into the interior of the casing; a shaft rotatingly coupled to the motor at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the motor coupling positioned on the frame housing and the auger portion positioned in the cylindrical casing; and, the variable speed motor having a first speed to rotate the auger to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
There is yet further provided a pump for transferring a molten metal from a melt furnace, the pump comprising: a means for providing drive torque; a frame housing with means for mounting the drive torque means; a transfer tube with a vertical portion for maintaining a predetermined head level of the molten metal; an auger housing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the auger housing at a bottom thereof communicating an interior of the auger housing to the transfer tube, and one or more second openings for admitting the molten metal into the interior of the auger housing; an auger shaft rotatingly coupled to the drive torque means at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the coupling positioned in the frame housing and the auger portion positioned in the auger housing; the drive torque means having a first speed to rotate the auger shaft to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
In the present invention, a molten magnesium pump comprises an upper and lower portion.
The upper portion consists of an inverter duty electric motor which is operatively connected to a PLC. The PLC controls output by the motor thereby controlling the pour speed and pour time of the pump. A coupler attaches the motor to the auger shaft. The shaft is centered and aligned between upper and lower portions. The shaft is held in position by various guide bearings located exclusively within the upper portion.
The lower portion comprises a cylindrical casing which is immersed in the molten magnesium bath. The top portion of the casing contains a gas inlet aperture in which gases such as argon, SF6 or SO2 are fed. Located near the base of the casing is an inlet aperture which permits the molten magnesium to enter the pump casing. As the auger shaft is rotated by the motor, displacing the molten magnesium downwardly and forcing it out of the pump and into the heated transfer tube for delivery to the die casting machine. At idle speed, the auger maintains a head of metal in the transfer tube and agitates the molten metal in the bath.
Further objects and features of the present invention will become apparent to those skilled in the art in the light of the following description and accompanying drawings.
6a BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which form part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicated like parts in the various views.
Figure 1 - a perspective view of the pump according to the present invention as positioned in a bath of molten magnesium Figure 2 - a perspective view of the pump according to the present invention as shown attached to a heated transfer tube BRIEF DESCRIPTION OF THE INVENTION
Referring to Figure 1 and 2, a preferred embodiment of the present invention is illustrated. The pump apparatus shown in Figure 1 is attached to the magnesium furnace and is located above the bath of molten magnesium. The auger and the cylindrical casing enclosing it are operatively immersed in the bath.
The inverter duty electric motor (1) is operatively connected to the vector high frequency drive which in turn, is operatively connected to a programmable logic controller (PLC) (not shown). The PLC is programmed to control the level of power delivered to the pump and the duration of operation of the pump. Specifically, the PLC controls the vector high frequency drive. The drive controls the amount of Hertz delivered to the motor thereby controlling the pour speed and the pour time of the pump.
The pump consists of 2 main parts, the upper portion (2) which is suspended above the molten magnesium bath during operation and the lower portion (3) which is immersed in the bath. The motor (1) is positioned at the top of the upper portion, resting on a steel plate (4) which is slightly larger in diameter than the motor itself. Two bolts (5) are threadingly engaged with the base of the steel plate and the motor, securing the motor in place. The steel plate (4) is attached to a second steel plate (6) by four cylindrical bars (7) running longitudinally between the two plates and bolted (8) to each plate on either end.
The second plate (6) is in turn, attached to a third plate (9) located at the top of the lower portion (3) by four cylindrical bars (10) running longitudinally between the plates. The bars are bolted (11) on either end to each plate. The two sets of cylindrical rods (7, 10) permits the easy handling of the pump apparatus while providing it with support.
A holding bearing or coupler (12) is located beneath the first plate and is attached to the auger shaft (13) and the motor (1). The holding bearing (12) holds the weight of the auger shaft (13) and positions it in place. The auger shaft (13) is centred within the internal diameter of the two portions, running the length of both, held in position by a set of guide bearings(14,15) located on either face of the second plate.
The lower portion is comprised of a cylindrical casing (16) in which the auger is located and aligned. Several inlet holes are located in the walls of the cylindrical casing. Two gas inlet apertures (17) are located near the top of the cylinder, in a portion of the cylindrical casing that remains above the level of the bath. Protective gases such as argon, SO2 or SF6 are introduced into the casing by means of the apertures. A
sealing cap (18) placed on top of the pump casing functions to seal the casing and contain the protective gases within. A seal is achieved by surrounding the internal diameter of the sealing cap (18) with graphite rope (not shown).
A second set of inlet holes (19) 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 depending on the application. For instance, when a large volume is required, a 4 inch pitch should be used. In contrast, a 2 inch pitch provides the accuracy required to pour a small volume of molten magnesium.
The auger (20) acts like a positive displacement pump. Typically, displacement is impeded by slippage of material past the auger. However, the density of magnesium is approximately twice that of water, resulting in a substantial decrease in slippage. As a result, 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 the connector (21).
The elbow shaped connector (21) is 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.
Referring to Figure 2, the connector (21) is attached to a heated transfer tube (30) which will convey the molten magnesium from the holding furnace to the die of the casting machine (not shown).
The effect of the inverter duty electric motor rotating the auger at idle speed results in a downward displacement of molten magnesium that allows for the maintenance and control of a head of molten metal at the end of the heated transfer tube. This also permits the near instantaneous acceleration and deceleration of the molten magnesium transfer at a pre-determined rate and quantity when the pump operates at pour speed. A
resulting benefit of this system is consistent and accurate shots of molten magnesium into a die cast machine.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.
It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.
Since many possible embodiments may be made of the invention without departing from the scope of the thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
An object of this invention is provide a pump for transferring molten magnesium to a die casting machine that is simple in construction, effective, easy to use and maintain, and is relatively inexpensive to manufacture.
A further object of the invention is to provide a pump which does not have any valves, guides, bearings or the like, in contact with molten magnesium, thus making the pump less vulnerable to failure and more reliable.
A further object of the invention is to provide a pump which constantly agitates the molten metal in the magnesium melt furnace. The agitation assists in keeping a constant bath temperature in the furnace when ingots are introduced into the bath.
Maintaining a constant temperature in the bath improves consistency and aids in preventing the premature release and deposits of magnesium metal alloys.
Agitation in the molten bath also assists in stabilizing the viscosity of the molten metal.
Maintaining a consistent viscosity improves both pour speed and pour. Pour time relates to the amount of time required for the pump to change from idle to pour speed.
The agitation is achieved by the auger which continues to rotate at idle speed to maintain a head in the transfer tube as described hereinafter. Naturally, at pour speed, the agitation is further increased. The agitation stabilizes the bath's temperature quickly, substantially reducing the amounts of alloy deposits and variations in viscosity.
There is provided a molten metal pump for transferring metal from a melt furnace by means of a transfer tube, the pump comprising upper and lower aligned portions, the upper portion comprising a frame housing for attachment to the melt furnace and an inverter duty electric motor mounted to the frame housing, the lower portion attached to the upper portion and immersable into the melt furnace, the lower portion comprising a cylindrical casing having an opening at a bottom thereof, a transfer tube connected at one end to the opening, and an auger within the casing connected to the inverter duty electric motor by means of a shaft, the opening being located lower than a bottom flute of the auger, the motor being operable at a first speed to rotate the shaft to transfer molten metal downwardly into the transfer tube in order to maintain a predetermined head within the tube and being further operable at a second speed to transfer a measured quantity of molten metal from the tube.
There is further provided a pump for transferring a molten metal from a melt furnace, the pump comprising: a variable speed motor; a frame housing with means for attaching the pump to the melt furnace; means for mounting the motor to the frame housing; a transfer tube comprising an elbow shaped connector and a vertical portion for maintaining a predetermined head level of the molten metal; a cylindrical casing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the casing at a bottom thereof connecting an interior of the casing to the elbow shaped connector of the transfer tube, and one or more second openings for admitting the molten metal into the interior of the casing; a shaft rotatingly coupled to the motor at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the motor coupling positioned on the frame housing and the auger portion positioned in the cylindrical casing; and, the variable speed motor having a first speed to rotate the auger to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
There is yet further provided a pump for transferring a molten metal from a melt furnace, the pump comprising: a means for providing drive torque; a frame housing with means for mounting the drive torque means; a transfer tube with a vertical portion for maintaining a predetermined head level of the molten metal; an auger housing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the auger housing at a bottom thereof communicating an interior of the auger housing to the transfer tube, and one or more second openings for admitting the molten metal into the interior of the auger housing; an auger shaft rotatingly coupled to the drive torque means at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the coupling positioned in the frame housing and the auger portion positioned in the auger housing; the drive torque means having a first speed to rotate the auger shaft to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
In the present invention, a molten magnesium pump comprises an upper and lower portion.
The upper portion consists of an inverter duty electric motor which is operatively connected to a PLC. The PLC controls output by the motor thereby controlling the pour speed and pour time of the pump. A coupler attaches the motor to the auger shaft. The shaft is centered and aligned between upper and lower portions. The shaft is held in position by various guide bearings located exclusively within the upper portion.
The lower portion comprises a cylindrical casing which is immersed in the molten magnesium bath. The top portion of the casing contains a gas inlet aperture in which gases such as argon, SF6 or SO2 are fed. Located near the base of the casing is an inlet aperture which permits the molten magnesium to enter the pump casing. As the auger shaft is rotated by the motor, displacing the molten magnesium downwardly and forcing it out of the pump and into the heated transfer tube for delivery to the die casting machine. At idle speed, the auger maintains a head of metal in the transfer tube and agitates the molten metal in the bath.
Further objects and features of the present invention will become apparent to those skilled in the art in the light of the following description and accompanying drawings.
6a BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which form part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicated like parts in the various views.
Figure 1 - a perspective view of the pump according to the present invention as positioned in a bath of molten magnesium Figure 2 - a perspective view of the pump according to the present invention as shown attached to a heated transfer tube BRIEF DESCRIPTION OF THE INVENTION
Referring to Figure 1 and 2, a preferred embodiment of the present invention is illustrated. The pump apparatus shown in Figure 1 is attached to the magnesium furnace and is located above the bath of molten magnesium. The auger and the cylindrical casing enclosing it are operatively immersed in the bath.
The inverter duty electric motor (1) is operatively connected to the vector high frequency drive which in turn, is operatively connected to a programmable logic controller (PLC) (not shown). The PLC is programmed to control the level of power delivered to the pump and the duration of operation of the pump. Specifically, the PLC controls the vector high frequency drive. The drive controls the amount of Hertz delivered to the motor thereby controlling the pour speed and the pour time of the pump.
The pump consists of 2 main parts, the upper portion (2) which is suspended above the molten magnesium bath during operation and the lower portion (3) which is immersed in the bath. The motor (1) is positioned at the top of the upper portion, resting on a steel plate (4) which is slightly larger in diameter than the motor itself. Two bolts (5) are threadingly engaged with the base of the steel plate and the motor, securing the motor in place. The steel plate (4) is attached to a second steel plate (6) by four cylindrical bars (7) running longitudinally between the two plates and bolted (8) to each plate on either end.
The second plate (6) is in turn, attached to a third plate (9) located at the top of the lower portion (3) by four cylindrical bars (10) running longitudinally between the plates. The bars are bolted (11) on either end to each plate. The two sets of cylindrical rods (7, 10) permits the easy handling of the pump apparatus while providing it with support.
A holding bearing or coupler (12) is located beneath the first plate and is attached to the auger shaft (13) and the motor (1). The holding bearing (12) holds the weight of the auger shaft (13) and positions it in place. The auger shaft (13) is centred within the internal diameter of the two portions, running the length of both, held in position by a set of guide bearings(14,15) located on either face of the second plate.
The lower portion is comprised of a cylindrical casing (16) in which the auger is located and aligned. Several inlet holes are located in the walls of the cylindrical casing. Two gas inlet apertures (17) are located near the top of the cylinder, in a portion of the cylindrical casing that remains above the level of the bath. Protective gases such as argon, SO2 or SF6 are introduced into the casing by means of the apertures. A
sealing cap (18) placed on top of the pump casing functions to seal the casing and contain the protective gases within. A seal is achieved by surrounding the internal diameter of the sealing cap (18) with graphite rope (not shown).
A second set of inlet holes (19) 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 depending on the application. For instance, when a large volume is required, a 4 inch pitch should be used. In contrast, a 2 inch pitch provides the accuracy required to pour a small volume of molten magnesium.
The auger (20) acts like a positive displacement pump. Typically, displacement is impeded by slippage of material past the auger. However, the density of magnesium is approximately twice that of water, resulting in a substantial decrease in slippage. As a result, 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 the connector (21).
The elbow shaped connector (21) is 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.
Referring to Figure 2, the connector (21) is attached to a heated transfer tube (30) which will convey the molten magnesium from the holding furnace to the die of the casting machine (not shown).
The effect of the inverter duty electric motor rotating the auger at idle speed results in a downward displacement of molten magnesium that allows for the maintenance and control of a head of molten metal at the end of the heated transfer tube. This also permits the near instantaneous acceleration and deceleration of the molten magnesium transfer at a pre-determined rate and quantity when the pump operates at pour speed. A
resulting benefit of this system is consistent and accurate shots of molten magnesium into a die cast machine.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.
It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.
Since many possible embodiments may be made of the invention without departing from the scope of the thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
Claims (15)
1. A molten metal pump for transferring metal from a melt furnace by means of a transfer tube, the pump comprising upper and lower aligned portions, the upper portion comprising a frame housing for attachment to the melt furnace and an inverter duty electric motor mounted to the frame housing, the lower portion attached to the upper portion and immersable into the melt furnace, the lower portion comprising a cylindrical casing having an opening at a bottom thereof, a transfer tube connected at one end to the opening, and an auger within the casing connected to the inverter duty electric motor by means of a shaft, the opening being located lower than a bottom flute of the auger, the motor being operable at a first speed to rotate the shaft to transfer molten metal downwardly into the transfer tube in order to maintain a predetermined head within the tube and being further operable at a second speed to transfer a measured quantity of molten metal from the tube.
2. The pump as claimed in claim 1, wherein the cylindrical casing is vented to the melt furnace by means of a set of inlet apertures in which molten metal may enter the casing.
3. The pump as claimed in claim 1 or 2 wherein the cylindrical casing contains a set of gas inlet apertures at a top thereof through which a protective gas may be introduced.
4. The pump as claimed in any one of claims 1 to 3 wherein the transfer tube is heated.
5. The pump as claimed in any one of claims 1 to 4 wherein the frame housing comprises a first plate to which the motor is mounted, a second plate attached to the first plate by a first set of bars running longitudinally between the first and second plates, and a third plate attached to the lower portion, the third plate attached to the second plate by a second set of bars running longitudinally between the second and third plates.
6. A pump for transferring a molten metal from a melt furnace, the pump comprising:
a variable speed motor;
a frame housing with means for attaching the pump to the melt furnace;
means for mounting the motor to the frame housing;
a transfer tube comprising an elbow shaped connector and a vertical portion for maintaining a predetermined head level of the molten metal;
a cylindrical casing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the casing at a bottom thereof connecting an interior of the casing to the elbow shaped connector of the transfer tube, and one or more second openings for admitting the molten metal into the interior of the casing;
a shaft rotatingly coupled to the motor at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the motor coupling positioned on the frame housing and the auger portion positioned in the cylindrical casing; and, the variable speed motor having a first speed to rotate the auger to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
a variable speed motor;
a frame housing with means for attaching the pump to the melt furnace;
means for mounting the motor to the frame housing;
a transfer tube comprising an elbow shaped connector and a vertical portion for maintaining a predetermined head level of the molten metal;
a cylindrical casing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the casing at a bottom thereof connecting an interior of the casing to the elbow shaped connector of the transfer tube, and one or more second openings for admitting the molten metal into the interior of the casing;
a shaft rotatingly coupled to the motor at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the motor coupling positioned on the frame housing and the auger portion positioned in the cylindrical casing; and, the variable speed motor having a first speed to rotate the auger to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
7. The pump of claim 6 wherein the motor is an inverter duty electric motor.
8. The pump of claim 6 or 7 wherein the casing has one or more third openings a top thereof for admitting a protective gas into the interior of the casing.
9. The pump of any one of claims 6 to 8 wherein the transfer tube further comprises a horizontal portion for transporting the molten metal from the melt furnace.
10. The pump of claim 9 wherein at least the horizontal portion of the transfer tube is heated.
11. The pump of any one of claims 6 to 10 wherein the weight of the shaft is borne by a holding bearing on the frame housing.
12. The pump of any one of claims 6 to 11 wherein the shaft is held in alignment by one or more sets of guide bearings on the frame housing.
13. The pump of any one of claims 6 to 12 wherein the weight of the cylindrical casing is borne by the frame housing.
14. The pump as claimed in any one of claims 6 to 13 wherein the frame housing comprises a first plate to which the motor is mounted, a second plate attached to the first plate by a first set of bars running longitudinally between the first and second plates, and a third plate attached to the cylindrical casing, the third plate attached to the second plate by a second set of bars running longitudinally between the second and third plates.
15. A pump for transferring a molten metal from a melt furnace, the pump comprising:
a means for providing drive torque;
a frame housing with means for mounting the drive torque means;
a transfer tube with a vertical portion for maintaining a predetermined head level of the molten metal;
an auger housing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the auger housing at a bottom thereof communicating an interior of the auger housing to the transfer tube, and one or more second openings for admitting the molten metal into the interior of the auger housing;
an auger shaft rotatingly coupled to the drive torque means at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the coupling positioned in the frame housing and the auger portion positioned in the auger housing;
the drive torque means having a first speed to rotate the auger shaft to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
a means for providing drive torque;
a frame housing with means for mounting the drive torque means;
a transfer tube with a vertical portion for maintaining a predetermined head level of the molten metal;
an auger housing vertically aligned with the frame housing and at least partially immersible in the molten metal, a first opening in the auger housing at a bottom thereof communicating an interior of the auger housing to the transfer tube, and one or more second openings for admitting the molten metal into the interior of the auger housing;
an auger shaft rotatingly coupled to the drive torque means at a first end thereof and having flutes formed on a portion adjacent a second end thereof to define an auger portion, the flutes being located above the first opening in the casing, the coupling positioned in the frame housing and the auger portion positioned in the auger housing;
the drive torque means having a first speed to rotate the auger shaft to push molten metal downwardly into the transfer tube in order to maintain the predetermined head level and a second speed to transfer a quantity of molten metal from the tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2284985 CA2284985C (en) | 1999-09-30 | 1999-09-30 | Auger pump for handling magnesium and magnesium alloys |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2284985 CA2284985C (en) | 1999-09-30 | 1999-09-30 | Auger pump for handling magnesium and magnesium alloys |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2284985A1 CA2284985A1 (en) | 2001-03-30 |
| CA2284985C true CA2284985C (en) | 2008-08-12 |
Family
ID=4164301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2284985 Expired - Fee Related CA2284985C (en) | 1999-09-30 | 1999-09-30 | Auger pump for handling magnesium and magnesium alloys |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2284985C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10322450B2 (en) | 2014-02-04 | 2019-06-18 | Pyrotek, Inc. | Adjustable flow overflow vortex transfer system |
| US20230285921A1 (en) * | 2022-03-14 | 2023-09-14 | Hyundai Motor Company | Methane cracking apparatus |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2559108C2 (en) | 2009-06-16 | 2015-08-10 | Пиротек, Инк. | Overflow vortex transporting unit |
| CN112762712B (en) * | 2020-12-17 | 2022-09-23 | 圣航粉末冶金河北有限公司 | Composite alloy preparation system |
| CN113600788B (en) * | 2021-07-14 | 2022-12-27 | 江西省铭鑫荣智能科技有限公司 | Die-casting mechanical demolding and separating equipment for manufacturing precise structural part and implementation method |
-
1999
- 1999-09-30 CA CA 2284985 patent/CA2284985C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10322450B2 (en) | 2014-02-04 | 2019-06-18 | Pyrotek, Inc. | Adjustable flow overflow vortex transfer system |
| US20230285921A1 (en) * | 2022-03-14 | 2023-09-14 | Hyundai Motor Company | Methane cracking apparatus |
| US12478940B2 (en) * | 2022-03-14 | 2025-11-25 | Hyundai Motor Company | Methane cracking apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2284985A1 (en) | 2001-03-30 |
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| EEER | Examination request | ||
| MKLA | Lapsed |