Technical Field
[0001] The present invention relates to a molten metal feeding system for each time feeding
a constant quantity of molten metal, such as aluminum alloy or others, from a molten
metal holding furnace to a die casting machine in which the molten metal is replenished
and stored in the holding furnace after being melted in a metal melting furnace.
Background Art
[0002] A conventional molten metal feeding system is so constructed that molten metal kept
in a holding furnace is forced onwards through a molten metal delivery tube into a
die casting machine by the aid of an electromagnetic pump set in the delivery tube
which extends from the holding furnace to the die casting machine.
[0003] Where the molten metal is of nonferrous metal such as aluminum alloy and the like
and undesiredly gets mixed with magnetic material such as iron and the like, the electromagnetic
pump of a conventional feeding system can become clogged with the portion of magnetic
material which is attracted to the inside of the electromagnetic pump, resulting in
a breakdown. Further problems are raised in maintaining the quantity and constant
feed of the delivered molten metal, and hence in the cost of production, since the
molten metal flowing in the delivery tube cannot be immediately halted when the pump
stops. Also, the electromagnetic pump is expensive.
[0004] A system according to the preamble of claim 1 is known from JP-A-8-10937.
[0005] In view of the above-described problems, it is an objective of the present invention
to provide a molten metal feeding system capable of each time steadily feeding a constant
quantity the molten metal to the die casting machine without said problems, and at
a reduced production cost.
[0006] According to the present invention, there is provided a system for feeding a constant
quantity of molten metal to a die casting machine comprising: a sealed pot having
an ingress port provided on a bottom side of the sealed pot so as to open upwardly
and an egress port, said sealed pot being arranged at a predetermined level within
a molten metal holding furnace; a molten metal delivery tube having one end communicating
with the egress port and the other end communicating with a pouring gate of a die
casting machine; a pair of valves for opening and closing the ingress port and the
egress port; interconnected with each of the valves; a level detecting mechanism for
detecting an upper limit level L1 and a lower limit level L2 of the molten metal within
the pot; and an internal pressure controller system adapted for increasing the internal
pressure in the pot by charging an inactive gas and adapted for decreasing the internal
pressure in the pot by discharging the once compression-charged inactive gas from
the pot; characterized in that: the one end of said delivery tube extends into the
inside of the pot from a side wall at the lower end of the pot; said egress port is
provided in said one end of the delivery tube so as to open upwardly in parallel to
said ingress port
; and the valves are each shaped like a bar and are arranged in parallel within the
pot for opening and closing the ingress port and the egress port of the pot by vertical
motion produced by the valve actuating means.
[0007] According to the system for feeding a constant quantity of molten metal to a die
casting machine, the molten metal let in through the ingress port into the inside
of the pot is depressed from the upper limit level L1 to the lower limit level L2
by the pressure of the charged gas and is thereby delivered from the inside of the
pot through the egress port along the delivery tube. Therefore, a constant quantity
of the molten metal within the molten metal holding furnace can each time be automatically
delivered steadily to the die casting machine. Where the molten metal is of nonferrous
metal such as aluminium alloy and the like and undesiredly gets mixed with magnetic
material, there is no likelihood that the inside of the delivery tube will become
clogged with the ingredient of magnetic material and the system fall into a breakdown,
as in the case of using the electromagnetic pump, since the inside pressure system
is incorporated to let the molten metal in and out with the aid of the inactive gas.
This enables the production to be achieved at a reduced relative cost.
[0008] Further, according to this system for feeding a constant quantity of molten metal,
a pair of the valves for each opening and closing the ingress port and the egress
port of the pot are provided in juxtaposition, and the inside pressure controller
system is provided for decreasing the inside pressure in the pot by discharging the
once compression-charged inactive gas from the pot so that, when the pressure controller
system performs the discharge of the inactive gas from the pot by switching the switch
valve, the molten metal in the holding furnace is forced to flow through the ingress
port into the pot in a state where the valve for the egress port is closed due to
downward motion of valve. Therefore, the quantity of the molten metal flowing from
the holding furnace into the pot can be regulated quantitatively to be a constant
amount, and thus the quantity delivered from the pot each time can be kept to a constant
quantity. In primary embodiments of the invention, the once compression-charged inactive
gas is discharged to the open air.
[0009] Further, according to the present system for feeding a constant quantity of molten
metal to a die casting machine, a pair of valves are arranged inside the pot in parallel
to one another and allowed to move vertically in the pot which is shut perfectly to
the open air, i.e. the inside of the pot is sealed in perfect separation from the
molten metal inside the molten metal holding furnace communicating with the open air,
and the ingress port and the egress port provided on the bottom side of the pot are
opened/closed by the valves on the inside of the sealed pot. This enables the molten
metal to be fed through the egress port without the entry of oxides.
[0010] According to a modification of the present invention, the internal pressure controller
system discharges the once compression-charged gas from the pot to reduce the internal
pressure in the pot by sucking the once compression-charged inactive gas forcibly
from the pot, to thereby allow the molten metal into the pot through the ingress port.
[0011] According to the modified system for feeding a constant quantity of molten metal
constant quantity of, a pair of valves, each for opening and closing one of the ingress
port and the egress port of the pot, are provided in juxtaposition and an inside pressure
controller system is provided for decreasing the inside pressure in the pot by sucking
the once compression-charged inactive gas forcibly from the pot. Therefore, in addition
to the effects of the modification, where the surface of a body of the molten metal
stored in the holding furnace is lessened and thus lowered by the delivery of the
molten metal from the pot, the upper limit level L1 on the inside of the pot can always
be kept to a fixed position, so that there becomes no need for frequent replenishment
of the molten metal holding furnace with supplemental molten metal, resulting in practical
use of the supplement work of the molten metal and delivery in a more consistent quantity.
[0012] In a system for feeding molten metal in constant quantity to a die casting machine
according to the above aspects, the valve actuating means comprises a fluid pressure
actuator erected on an upper side of the pot, with a piston rod, thereof joined to
the valve, which valve is shaped like a bar.
[0013] Further, according to the modified system for feeding molten metal in constant quality
to a die casting machine, a pair of the valves are arranged inside the pot in parallel
to one another and allowed to move vertically in the pot which is shut perfectly to
the open air, i.e. the inside of the pot is sealed in perfect separation from the
molten metal inside the molten metal holding furnace communicating with the open air,
and the ingress port and the egress port provided on the bottom side of the pot are
opened and closed by the valves on the inside of the sealed pot. This enables the
molten metal to be fed through the egress port without the entry of oxides.
[0014] According to the above systems for feeding a constant quantity of molten metal the
fluid pressure actuator may be mounted on the upper side of the pot as a driving means
of the valve and be joined to the bar-shaped valve, so that the driving means of the
valve can be simplified and made compact.
[0015] Further, in the systems above, according to the first aspect and modification thereof,
the pot, the valve and the molten metal delivery tube are each made out of ceramics.
[0016] According to this system, for feeding molten metal in constant quantity, since the
pot, the valve and the molten metal delivery tube are each made out of ceramics, they
are superior in heat resistance and can be produced at a reduced cost.
[0017] Yet further, in the systems above according to the first and second aspects, the
ingress port of the pot may be provided on the outside thereof with a filter, made
from ceramic, for removing impure materials.
[0018] According to this system, the mounting of the filter on ingress port on the outer
side of the pot enables the removing of oxides, dust and the other particles contained
in the molten metal in the holding furnace, and hence delivery of molten metal only
of a good quality to the die casting machine.
Brief Description of the Drawings
[0019] To enable a better understanding of the present invention, and to show how the same
may be carried into effect, reference will now be made by way of example only, to
the drawings, in which:
Fig. 1 is an elevational side view, in longitudinal section, of the molten metal feeding
system of the first specific form of the invention;
Fig. 2 is an enlarged section of a part of the molten metal feeding system shown in
Fig. 1;
Fig. 3 is an elevational side view, in longitudinal section, of the molten metal feeding
system of the second specific form of the invention; and
Fig. 4 is an enlarged section of one embodiment of a level detecting mechanism.
Detailed Description
[0020] The first specific form of the molten metal feeding system of the invention shown
in Fig. 1 is a particular application to a case in which molten metal, especially
of aluminum alloy, is fed to a die casting machine. Fig. 2 shows the enlarged section
of a part of the first specific form. In these figures, the numeral 1 indicates a
pot of hollow cylinder closed at the bottom, which has a molten metal ingress port
2 and a molten metal egress port 3 at the position related to the bottom. The pot
1 is made out of ceramics and is arranged perpendicularly at a predetermined level
inside an open type molten metal holding furnace 5 while the upper end 1a of the pot
1 is supported in a sealed condition by a support block 4 of heat-resistant material
meeting the necessary requirements for such an application and the remainder of the
pot 1 is suspended from the support block 4. The holding furnace 5 contains a body
of molten metal 6 of aluminum alloy stored substantially fully within the furnace,
which molten metal is supplied from a metal melting furnace. In this manner, the pot
1 is immersed, as shown in Fig. 1, in the body of molten metal 6.
[0021] The numeral 7 indicates a molten metal delivery tube made of ceramics, of which one
end is communicated with the egress 3 of the pot 1 and the other end is adapted to
be communicated with a pouring gate (not shown) of a die casting machine M. The delivery
tube 7 has three sections, i.e. a vertical section 7a extending vertically from the
egress 3 along the outside of the pot 1, a bend section 7b passing through the support
block 4 and supported therein, and a horizontal section 7c running horizontally from
the bend section to the die casting machine M. A free end 7d of the horizontal section
7c is adapted to be pressed on the pouring gate of the casting machine M. Incidentally,
a heater (omitted in the drawing) is attached to the delivery tube 7 so that the molten
metal from the pot 1 can be fed while being kept at the appropriate temperature.
[0022] The numeral 8 indicates a valve for opening and closing the ingress port 2 of the
pot 1 due to the motion in a direction perpendicular thereto of a stroke exerted by
a fluid pressure actuator 9 serving as a means for actuating the valve 1. The valve
8 is made of ceramics and comprises, as shown in Fig. 2, a valve proper 8a, rounded
at the lower end and a valve bar 8b, hollow on the inside. The fluid pressure actuator
9 is erected on the support block 4 and its piston rod 9a is inserted into the support
block 4 to be capable of sliding in a sealed manner, and is joined to the valve bar
8b on the inside of the support block 4. In this manner, the elongating action (extension)
of the actuator 9 causes downward motion of the valve bar 8b, to bring about the tight
engagement of the valve proper 8a with the ingress port 2, resulting in the closure
of the ingress port 2. On the other hand, the shortening action (retraction) of the
actuator 9 causes upward motion of the valve bar 8b, to bring about release of the
valve proper 8a from the ingress port 2, resulting in the opening of the ingress port
2.
[0023] In the embodiments illustrated in the drawings, the ingress port 2 on the bottom
side of the pot 1 is configured downwardly open manner, while the valve 8 for opening
and closing the ingress port 2 is arranged to move vertically within the pot 1. However,
in a modification (not forming part of the present invention), it is possible for
the ingress port 2 to be configured in such a manner as to open upwardly at a hollow
projection expanded laterally from a part of the bottom of the pot 1, while the valve
8 for opening and closing the ingress port 2 is arranged to move vertically on the
outside of the pot 1.
[0024] The numeral 10 indicates a level detecting mechanism for detecting the upper limit
level L1 and the lower limit level L2 of molten metal inside the pot 1. The upper
limit level L1 refers to a surface of molten metal within the pot 1 at the time of
starting to feed the molten metal to the die casting machine, and is inclined (under
gravity), to become identical to the surface level Lo of the body of molten metal
inside the holding furnace 5 and outside the pot 1. On the other hand, the lower limit
level L2 refers to the surface of the molten metal within the pot 1 at the time of
ending the feeding of molten metal to the die casting machine. In the level detecting
mechanism 10 particularly shown as an example in Fig. 4. A flange member 12 is fixed
on the support block 4 by way of a plate piece 11 located just above the pot 1, a
guide sleeve 13 being arranged vertically and fixed in the support block 4, the plate
piece 11 and the flange member 12 in a piercing manner, and an elongated floating
shaft 14 being so arranged as to extend through the guide sleeve 13 while the lower
and upper ends of the floating shaft 14 are provided with a float 15 and a detection
member 16, respectively. Further, a transparent cylindrical cover 17, with an upper
end thereof closed, is arranged vertically and fixed on the flange member 12 so as
to accommodate the upwardly extending portion of the floating shaft 14 as well as
the detection member 16. In the outer side of the cylindrical cover 17, there are
provided photoelectric switches 18, 19 as a detecting means of the detection member
16 at the upper and lower levels, so as to be adjustable in their own level positions,
which switches each comprise a pair consisting of a light projector 18a, 19a and a
light receiver 18b, 19b.
[0025] In this manner, the upper side photoelectric switch 18 can detect the upper limit
level L1 of the molten metal within the pot by way of the detection member 16, and
the lower side photoelectric switch 19 can detect the lower limit level L2 by way
of the detection member 16.
[0026] The above-described plate piece 11, flange member 12, guide sleeve 13, float shaft
14, float 15, detection member 16 and cylindrical cover 17 are each made out of ceramics.
The detecting means of the detection member 16 is not limited to the photoelectric
switch, but can use the other switches such as a proximity switch. Incidentally, the
above-described level detecting mechanism 10 is of a float type, but can also be of
an optical type to directly measure the surface of the molten metal 6 in the pot 1
by way of laser beams, or be of a capacitance type level gauge.
[0027] The numeral 20 in Fig. 1 indicates an inside pressure controller system adapted for
increasing the inside pressure in the pot 1 by charging an inactive gas (a nitrogen
gas or a dry air difficult to react with the molten metal), and for decreasing the
inside pressure in the pot 1 by discharging the once compression-charged inactive
gas to the open air. The inside pressure controller system 20 comprises a gas charging
source 22 which includes a tank for accommodating an inactive gas and a gas charging
pump and is connected by way of a guide line 23 to a gas passing pipe 21 (see Fig.
1) which is arranged in the plate piece 11 and the support block 4 so as to communicate
with the inside of the pot 1. In the guide line 23, there are interposed a pressure
adjusting valve 24 and an electromagnetic switch valve 25. The electromagnetic switch
valve 25 is electrically connected with a control unit (not shown in the drawing)
of the fluid pressure actuators 9, 39 and the photoelectric switches 18, 19 of the
level detecting mechanism 10. As for the pressure adjusting valve 24, an electric
control type pressure control valve can be used for altering the inside pressure in
the pot 1 as desired.
[0028] In this manner, for increasing the inside pressure in the pot 1 by charging the inactive
gas, the switch valve 25 is operated so as to let the gas flow from the gas charging
source 22 to the gas passing pipe 21. On the other hand, for decreasing the inside
pressure in the pot 1, the switch valve 25 is operated so as to stop the gas flowing
from the gas charging source 22 and make the gas passing pipe 21 communicate with
the open air through a gas discharging route. Adjustment of the inside pressure in
the pot is performed by the pressure adjusting valve 24. Incidentally, for the gas
charging source 22, a high pressure cylinder filled with inactive gas can also be
used.
[0029] In the ingress port 2 of the pot 1, there is mounted on the outside thereof a filter
26, made of ceramics, for removing impure materials such as oxides, dust and others
contained in the molten metal 6 in the holding furnace 5. The filter 26 is formed
into a shape like a box as shown in Fig. 2, a semisphere or other desired shape, and
is porous with about 10 to 60 meshes. The mounting of the filter 26 is performed by
engaging an upper collar portion 26a of the filter 26 with a bent projection 27 provided
on the outside of the bottom of the pot 1. The filter 26 is not essential, but is
used if need be.
[0030] The above-described delivery tube 7 is communicated with a horizontal displacement
mechanism 28 of a fluid pressure actuator type so as to move in a horizontal direction
together with the pot 1. Particularly, the horizontal displacement mechanism 28 is
so constructed, as shown in Figs. 1 and 2, that pairs of right and left wheels 32,
installed by way of brackets 31 on the support block 4, can roll on right and left
horizontal guide rails 30a which are formed on support frames 30 at the right and
left sides extended horizontally from both the lateral sides of the upper end of a
base frame 29 standing upright close to the holding furnace 5, and that a fluid pressure
actuator 33 installed on the base frame 29 is connected by a piston rod 33a and a
connecting rod 33b to the support block 4. The telescopic action of the fluid pressure
actuator 33 enables the pot 1 and the delivery tube 7 integral with the support block
4 to move longitudinally in a horizontal direction and thereby can ensure the engagement
of the free end 7d of the delivery tube 7 with the pouring gate (not shown) of the
die casting machine M in a pressing manner.
[0031] The numeral 38 indicates a valve for opening and closing the egress port 3 of the
pot 1 due to the perpendicular motion with a fluid actuator 39.
[0032] Particularly, the valve 38 for the egress port 3 is similar to the valve 8 for the
ingress port 2, and is made of ceramic and comprises, as shown in Fig. 5, a valve
proper 38a rounded at the lower end and a valve bar 38b. The fluid pressure actuator
39 is erected on the support block 4 side by side with the fluid pressure actuator
9 for the ingress valve 8 and its piston rod 39a is inserted into the support block
4 to be capable of sliding in a sealed manner, and is joined to the valve bar 38b
in the inside of the support block 4. In this manner, the elongating action (section)
of the actuator 39 causes downward motion of the valve bar 38b, to bring about tight
engagement of the valve proper 38a with the egress port 3, resulting in the closure
of the egress port 3. On the other hand, the shortening action of the actuator 39
causes upward motion of the valve bar 38b, to bring about the release of the valve
proper 38a from the egress port 13, resulting in the opening of the egress port 3.
[0033] In operation, the molten metal feeding system constructed above, in a situation where
the ingress port 2 of the pot 1 is put in an open position due to the upward motion
of the ingress valve 8 while the egress port 3 of the pot 1 is put in a closed position
due to the downward motion of the egress valve 38, the inside of the pot 1 is caused
to communicate with the open air by the inside pressure controller system 20, so that
the molten metal 6 in the holding furnace 5 flows through the ingress port 2 into
the inside of the pot 1 and rises up to the upper limit level L1, which is detected
by the level detecting mechanism 10. Particularly, with the rise of the molten metal
within pot 1, the float 15 on the surface of the molten metal rises and the detection
member 16, by way of the floating shaft 14, also rises. When the detection member
16 rises to a position related to the upper limit level L1, the detection member 16
is sensed by the photoelectric switch 18.
[0034] At this time, the sensing signal from the photoelectric switch 18 activates the fluid
pressure actuator 39 into an elongating motion to move the valve 38 downwardly to
close the ingress port 2, and also activates the fluid pressure actuator 39 into an
elongating motion to move the valve 38 upwardly to open the egress port 3. At the
same time, the inside pressure controller system 20 activates so as to charge the
inactive gas through the gas passing pipe 21 into the inside of the pot 1. Thereby,
the molten metal within the pot 1 is put under pressure and is caused to flow through
the egress port 3 into the delivery tube 7. Then, the molten metal surface inside
the pot 1 drops down to the lower limit level L2, and the detection member 16 also
drops to a position related to the lower limit level L2, which is sensed by the photoelectric
switch 19. At this time, the sensing signal from the photoelectric switch 19 activates
the fluid pressure actuator 9 into a shortening motion to move the valve 8 upwardly
and open the ingress port 2, and also activates the fluid pressure actuator 39 into
an elongating motion to move the valve 38 downwardly to close the egress port 3. At
the same time, the inside pressure controller system 20 activates so as to discharge
the once compression-charged inactive gas within the pot 1 from the pot 1, through
the gas passing pipe 21 and the gas discharging route formed by the switch valve 25
to the open air. Thereby, the molten metal in the holding furnace 5 flows into the
pot 1. Sequentially, those processes are repeated.
[0035] According to the above-described molten metal feeding system, the molten metal within
the pot 1, which, as described above, is put under pressure by the inactive gas charged
into the pot 1 and drops from the upper limit level L1 to the lower limit level L2,
is fed through the delivery tube 7 by a specified quantity equivalent to the product
of the interval between both the limit levels L1, L2 and the sectional area of the
inside of the pot 1. As a result, the repetition of the above processes enables feeding
of the molten metal in a quantity proportional to the repetition. The fed quantity
of the molten metal is adjustable as desired by altering vertically the positions
of the upper and lower side photoelectric switches 18 and 19 of the level detecting
mechanism. In this case, either or both of the upper and lower side photoelectric
switches 18 and 19 may be changed in position.
[0036] In the present molten metal feeding system, when the molten metal in the pot 1 lowers
down to the lower limit level L2 and the detection signal activates the pressure controller
system 20 so as to discharge the once compression-charged gas, from the pot 1 with
the switching of the switch valve 25, the molten metal in the holding furnace 5 is
forced to flow through the ingress port 2 into the pot 1 in a state where the valve
38 for the egress port 3 is closed due to the downward motion of the valve 38. Accordingly,
the flowing quantity of the molten metal from the holding furnace 5 into the pot 1
can be regulated quantitatively. For example, there is no likelihood that a part of
the molten metal flown into the pot 1 escapes through the egress port 3 of the pot
1.
[0037] The second specific form of the molten metal feeding system of the invention shown
in Fig. 3 is different from the above-described first form in that there is provided
an inside pressure controller system 40 adapted to reduce also the inside pressure
in the pot 1 by sucking the once compression-charged inactive gas forcibly from the
pot 1. Except for this respect, the third specific form has the same construction
as the second specific form. Thus, the same constituent elements are indicated by
the same reference numerals and description of the same elements is omitted.
[0038] Particularly, the inside pressure controller system 40 comprises, as shown in Fig.
3, a gas tank 34 for accommodating an inactive gas and a gas charging pump 35 for
feeding the inactive gas within the tank 34 to the gas passing, pipe 21 to which tank
34 and pump 35 are both connected by a way of a guide line 36. In the guide line 36,
there are interposed a pressure adjusting valve 37 and an electromagnetic switch valve
41. Further, the electromagnetic switch valve 41 and the gas tank 34 are connected
by a bypass line 42, in which there are interposed a sucking pump 43 and a pressure
adjusting valve 44. The electromagnetic switch valve 41 is electrically connected
with a control unit (not shown in the drawing) of each of the fluid pressure actuators
9, 39 and the photoelectric switches 18, 19 of the level detecting mechanism 10.
[0039] In this manner, to increase the inside pressure in the pot 1 by charging the inactive
gas, the switch valve 41 is so operated as to cut off the bypass line 42 and let the
gas to flow from the gas charging pump 35 to the gas passing pipe 21. On the other
hand, to decrease the inside pressure in the pot 1, the switch valve 41 is operated
so as to stop the gas flowing from the gas charging pump 35 to the gas passing pipe
21 and release the bypass line 42. The adjustment of the inside pressure in the pot
1 is performed by the pressure adjusting valves 37, 44.
[0040] In operation the molten metal feeding system constructed as above, in a situation
where the ingress port 2 of the pot 1 is put in an open position due to the upward
motion of the ingress valve 8 while the egress port 3 of the pot 1 is put in a closed
position due to the downward motion of the egress valve 38, the inside of the pot
1 is sucked to the outside by the inside pressure controller system 40, so that the
molten metal 6 in the holding furnace 5 flows through the ingress port 2 into the
inside of pot 1 and rises up to the upper limit level L1, which is detected by the
level detecting mechanism 10. Particularly, with the rise of the molten metal within
pot 1, the float 15 on the surface of the molten metal rises and the detection member
16, by way of the floating shaft 14, also rises. When the detection member 16 raises
to a position related to the upper limit level L1, the detection member 16 is sensed
by the photoelectric switch 18.
[0041] At this time, the sensing signal from the photoelectric switch 18 activates the fluid
pressure actuator 9 into an elongating motion (extension) to move the valve 8 downwardly
to close the ingress port 2, and also activates the fluid pressure actuator 39 into
a shortening motion (retraction) to move the valve 38 upwardly to open the egress
port 3. At the same time, the inside pressure controller system 40 activates to charge
the inactive gas through the gas passing pipe 21 into the inside of the pot 1. Thereby,
the molten metal within the pot 1 is put under pressure and is caused to flow through
the egress port 3 into the delivery tube 7. Then, the molten metal surface within
the pot 1 drops down to the lower limit level L2, and the detection member 16 also
drops a position related to the lower limit level, which is sensed by the photoelectric
switch 19. At this time, the sensing signal from the photoelectric switch 19 activates
the fluid pressure actuator 9 into a shortening motion (retraction) to move the valve
8 upwardly to open the ingress port 2, and also activates the fluid pressure actuator
39 into an elongating motion (extension) to move the valve 38 downwardly to close
the egress port 3. At the same time, the inside pressure controller system 40 activates
to discharge or return the once compression-charged inactive gas in the inside of
the pot 1 to the gas tank 34 through the gas passing pipe 21 and the bypass line 42
opened by the switch valve 41. Thereby, the molten metal in the holding furnace 5
flows into pot 1. Sequentially, those processes are repeated.
[0042] According to the above-described molten metal feeding system the inside molten metal
in the pot 1, which, as described above, is put under pressure by the inactive gas
charged into the pot 1 and drops from the upper limit level L1 to the lower limit
level L2, is fed through the delivery tube 7 by a specified quantity equivalent to
the product of the interval between both the limit levels L1, and L2 and the sectional
area of the inside of the pot 1. As a result, the repetition of the above processes
enables the delivery of the molten metal of a quantity proportional to the repetition.
Similarly to the operations in the first and second specific forms, the delivered
quantity of the molten metal is adjustable as desired by altering vertically the position
of the upper and lower side photoelectric switches 18, 19 of the level detecting mechanism.
In this case, either or both of the upper and lower side photoelectric switches 18,
19 may be changed in position.
[0043] Especially, in the present molten metal feeding system, there is provided the valve
8 for the ingress port 2 and the valve 38 for the egress port 38 as well as the inside
pressure controller system 40 adapted to reduce the inside pressure in the pot 1 by
sucking the once compression-charged inactive gas forcibly from the pot 1. Accordingly,
where the surface Lo of a body of the molten metal 6 stored in the holding furnace
5 is lowered by the delivery of the molten metal from the pot 1, the upper limit level
L1 within the pot 1 can always be kept at a fixed position, so that there is no need
for frequent replenishment of the molten metal holding furnace 5 with supplemental
molten metal, resulting in practical use of the supplement work of the molten metal
to feed the metal in a more consistent quantity.
[0044] Incidentally, the above-described specific forms are the application are directed
mainly to the case of feeding the molten metal of aluminum, but are not limited thereto.
For example, it is possible to apply these systems to the cases of using magnesium
or others as the molten metal. In the case of using magnesium as the molten metal,
the pot, valves and delivery tube may be made out of iron.
Industrial Applicability
[0045] As evident from the above description, according to the present invention, a constant
quantity of the molten metal within the molten metal holding furnace can be automatically
fed steadily to the die casting machine. Where the molten metal is of nonferrous metal
such as aluminium alloy and the like and gets mixed with magnetic material, there
is no likelihood that the inside of the feeding system will become clogged by the
portion of magnetic material and the system fall into a breakdown, as in the case
of using the electromagnetic pump, since the inside pressure controller system is
incorporated for letting the molten metal in and out with the aid of inactive gas.
This enables the production at a relatively reduced cost. Further, the use of the
inactive gas prevents oxides from being formed on the molten metal surface in the
pot. In addition, since the molten metal can be fed without suffering a decrease in
temperature, it is not necessary to supply heat for maintaining the temperature of
the metal melting furnace and the molten metal furnace. This serves to save energy,
and enables the casting to achieve a high quality.
1. A system for feeding a constant quantity of molten metal to a die casting machine
comprising:
a sealed pot (1), having an ingress port (2) provided on a bottom side of the sealed
pot (1) so as to open upwardly and an egress port (3), said sealed pot (1) being arranged
at a predetermined level within a molten metal holding furnace (5) ;
a molten metal delivery tube (7) having one end (7a) communicating with the egress
port and the other end (7d) communicating with a pouring gate of a die casting machine
(M);
a pair of valves (8, 38) for opening and closing the ingress port (2) and the egress
port (3);
valve actuating means (9, 39) interconnected with each of the valves (8, 38);
a level detecting mechanism (10) for detecting an upper limit level L1 and a lower
limit level L2 of the molten metal (6) within the pot; and
an internal pressure controller system (20, 40) adapted for increasing the internal
pressure in the pot by charging an inactive gas and adapted for decreasing the internal
pressure in the pot by discharging the once compression-charged inactive gas from
the pot,
characterized in that:
the one end (7a) of said delivery tube (7) extends into the inside of the pot from
a side wall at the lower end of the pot;
said egress port (3) is provided in said one end of the delivery tube (7) so as to
open upwardly in parallel to said ingress port (2); and
the valves (8, 38) are each shaped like a bar and are arranged in parallel within
the pot (1) for opening and closing the ingress port (2) and the egress port (3) of
the pot by vertical motion produced by the valve actuating means (9, 39).
2. A system for feeding a constant quantity of molten metal to a die casting machine
according to Claim 1, wherein the internal pressure controller system (40) discharges
the once compression-charged inactive gas from the pot to reduce the internal pressure
in the pot by sucking the once compression-charged inactive gas forcibly from the
pot, to thereby allow the molten metal (6) into the pot through the ingress port (2).
3. A system for feeding a constant quantity of molten metal to a die casting machine
according to Claim 1, wherein the internal pressure controller system (20) discharges
the once compression-charged inactive gas from the pot to reduce the internal pressure
in the pot by discharging the once compression-charged inactive gas to the open air.
4. A system for feeding a constant quantity of molten metal to a die casting machine
according to claim 1, 2 or 3, wherein the valve actuating means comprise fluid pressure
actuators (9, 39) mounted on an upper side of the pot with respective piston rods
(9a, 39a) thereof joined to the respective valves (8, 38).
5. A system for feeding a constant quantity of molten metal to a die casting machine
according to any preceding claim, wherein the pot (1), the valves (8, 38) and the
molten metal delivery tube (7) are each made of ceramic material.
6. A system for feeding a constant quantity of molten metal to a die casting machine
according to any preceding claim, wherein the ingress port (2) of the pot (1) is provided
with an external filter (26) made of ceramic material for removing impure materials.
1. System zur Zufuhr einer konstanten Menge geschmolzenen Metalls zu einer Spritzguss-Maschine,
umfassend:
einen abgedichteten Tiegel (1), der an einer Bodenseite des abgedichteten Tiegels
(1) eine so vorgesehene Eintritts-Öffnung (2) aufweist, dass sie nach oben zu öffnen
ist, sowie eine Austritts-Öffnung (3), wobei der abgedichtete Tiegel (1) an einem
vorab bestimmten Niveau innerhalb des Halteofens (5) für das geschmolzene Metall angeordnet
ist;
ein Förderrohr (7) für geschmolzenes Metall, welches ein Ende (7a) aufweist, welches
mit der Austritts-Öffnung kommuniziert, und dessen anderes Ende (7d) mit einem Gießtor
der Spritzguss-Maschine (M) kommuniziert;
ein Paar von Ventilen (8, 38) zum Öffnen und Verschließen der Eintritts-Öffnung (2)
und der Austritts-Öffnung (3);
Ventil-Betätigungselemente (9, 39), die mit jedem der Ventile (8, 38) verbunden sind;
einen Niveau-Detektionsmechanismus (10) zum Detektieren eines oberen Grenzniveaus
L1 und eines unteren Grenzniveaus L2 des geschmolzenen Metalls (6) innerhalb des Tiegels;
und
ein Kontrollsystem (20, 40) für den internen Druck, welches zum Anheben des internen
Drucks in dem Tiegel durch Zufuhr eines inaktiven Gases sowie zum Absenken des internen
Drucks in dem Tiegel durch Ablassen des einmal zur Kompression zugeführten inaktiven
Gases aus dem Tiegel angepasst ist,
dadurch gekennzeichnet, dass:
das eine Ende (7a) des Förderrohrs (7) sich in das Innere des Tiegels von einer Seitenwand
an dem niedrigeren Ende des Tiegels erstreckt;
die Austritts-Öffnung (3) in dem einen Ende des Förderrohrs (7) so vorgesehen ist,
dass sie parallel zu der Eintritts-Öffnung (2) nach oben zu öffnen ist; und
die Ventile (8, 38) jeweils wie ein Stab geformt sind und parallel innerhalb des Tiegels
(1) zum Öffnen und Verschließen der Eintritts-Öffnung (2) und der Austritts-Öffnung
(3) des Tiegels durch die von den Ventil-Betätigungselementen (9, 39) produzierte
vertikale Bewegung angeordnet sind.
2. System zur Zufuhr einer konstanten Menge geschmolzenen Metalls zu einer Spritzguss-Maschine
gemäß Anspruch 1, wobei das Kontrollsystem (40) für den internen Druck das einmal
zur Kompression zugeführte inaktive Gas von dem Tiegel abgibt, um den internen Druck
in dem Tiegel durch Zwangssaugen des einmal zur Kompression zugeführten inaktiven
Gases aus dem Tiegel zu reduzieren, um hierdurch den Zutritt des geschmolzenen Metalls
(6) in den Tiegel durch die Eintritts-Öffnung (2) zu ermöglichen.
3. System zur Zufuhr einer konstanten Menge geschmolzenen Metalls zu einer Spritzguss-Maschine
gemäß Anspruch 1, wobei das Kontrollsystem (20) für den internen Druck das einmal
zur Kompression zugeführte inaktive Gas vom Tiegel ausgibt, um den internen Druck
im Tiegel durch Ausgeben des einmal zur Kompression zugeführten inaktiven Gases zur
Umgebungsluft zu reduzieren.
4. System zur Zufuhr einer konstanten Menge geschmolzenen Metalls zu einer Spritzguss-Maschine
gemäß Anspruch 1, 2 oder 3, wobei die Ventil-Betätigungselemente Fluiddruck-Stellglieder
(9, 39) umfassen, die an der oberen Seite des Tiegels mit an den jeweiligen Ventilen
(8, 38) verbundenen jeweiligen Kolbenstangen (9a, 39a) befestigt sind.
5. System zur Zufuhr einer konstanten Menge geschmolzenen Metalls zu einer Spritzguss-Maschine
gemäß einem der voranstehenden Ansprüche, wobei der Tiegel (1), die Ventile (8, 38)
sowie das Förderrohr (7) für geschmolzenes Metall jeweils aus einem keramischen Material
gefertigt sind.
6. System zur Zufuhr einer konstanten Menge geschmolzenen Metalls zu einer Spritzguss-Maschine
gemäß einem der voranstehenden Ansprüche, wobei die Eintritts-Öffnung (2) des Tiegels
(1) mit einem externen Filter (26) versehen ist, der zur Entfernung von Verunreinigungsmaterialien
aus keramischem Material erzeugt ist.
1. Système destiné à fournir une quantité constante de métal fondu à une machine à coulée
sous pression comprenant:
un creuset rendu étanche (1) comportant un orifice d'entrée (2) disposé sur un côté
inférieur du creuset rendu étanche (1) de manière à ouvrir vers le haut et un orifice
de sortie (3), ledit creuset rendu étanche (1) étant disposé à un niveau prédéterminé
à l'intérieur d'un four de conservation de métal fondu (5),
un tube de délivrance de métal fondu (7) ayant une première extrémité (7a) communiquant
avec l'orifice de sortie et l'autre extrémité (7d) communiquant avec un port d'une
machine à coulée sous pression (M),
une paire de vannes (8, 38) destinées à ouvrir et fermer l'orifice d'entrée (2) et
l'orifice de sortie (3),
des moyens d'actionnement de vannes (9, 39) reliés mutuellement avec chacune des vannes
(8, 38),
un mécanisme de détection de niveau (10) destiné à détecter un niveau limite supérieur
L1 et un niveau limite inférieur L2 du métal fondu (6) à l'intérieur du creuset, et
un système de contrôleur de pression interne (20, 40) conçu pour augmenter la pression
interne dans le creuset en chargeant un gaz inactif, et conçu pour diminuer la pression
interne dans le creuset en évacuant le gaz inactif chargé auparavant par compression
du creuset,
caractérisé en ce que :
la première extrémité (7a) dudit tube de délivrance (7) s'étend à l'intérieur du creuset
depuis une paroi latérale au niveau de l'extrémité inférieure du creuset,
ledit orifice de sortie (3) est disposé dans ladite première extrémité du tube de
délivrance (7) de manière à s'ouvrir vers le haut parallèlement audit orifice d'entrée
(2), et
les vannes (8, 38) sont chacune formées comme une barre et sont agencées en parallèle
à l'intérieur du creuset (1) afin d'ouvrir et fermer l'orifice d'entrée (2) et l'orifice
de sortie (3) du creuset par un mouvement vertical produit par le moyen d'actionnement
de vannes (9, 39).
2. Système destiné à fournir une quantité constante de métal fondu à une machine à coulée
sous pression selon la revendication 1, dans lequel le système de contrôleur de pression
interne (40) évacue le gaz inactif auparavant chargé par compression du creuset pour
réduire la pression interne dans le creuset en aspirant le gaz inactif chargé auparavant
par compression de manière forcée depuis le creuset, afin d'admettre ainsi le métal
fondu (6) dans le creuset au travers de l'orifice d'entrée (2).
3. Système destiné à fournir une quantité constante de métal fondu à une machine à coulée
sous pression selon la revendication 1, dans lequel le système de contrôleur de pression
interne (20) évacue le gaz inactif chargé auparavant par compression du creuset afin
de réduire la pression interne dans le creuset en évacuant le gaz inactif chargé auparavant
par compression à l'air extérieur.
4. Système destiné à fournir une quantité constante de métal fondu à une machine à coulée
sous pression selon la revendication 1, 2 ou 3, dans lequel les moyens d'actionnement
de vannes comprennent des actionneurs à pression de fluide (9, 39) montés sur un côté
supérieur du creuset, leurs tiges de pistons respectives (9a, 39a) étant réunies à
leurs vannes respectives (8, 38).
5. Système destiné à fournir une quantité constante de métal fondu à une machine à coulée
sous pression selon l'une quelconque des revendications précédentes, dans lequel le
creuset (1), les vannes (8, 38) et le tube de délivrance de métal fondu (7) sont chacun
constitués de matériau de céramique.
6. Système destiné à fournir une quantité constante de métal fondu à une machine à coulée
sous pression selon l'une quelconque des revendications précédentes, dans lequel l'orifice
d'entrée (2) du creuset (1) est muni d'un filtre externe (26) réalisé en matériau
de céramique afin d'éliminer les matériaux impurs.