Abstract
The invention relates to a method for the weight-accurate filling
of ingot molds in a non-iron casting machine, e.g. a copper anode
casting machine or a zinc anode casting machine, which is configured
in the form of casting wheels that are use for production in a fully
mechanized casting operation and are provided with the ingot molds.
The aim of the invention is to obtain the desired precise-weight quality
of a piece and exact plane parallelism of the bordering surfaces thereof.
Said aim is achieved by carrying out the following steps: first, a
liquid metal is introduced into an intermediate trough (4,4') at a
regulated mass flow rate, the continuous dynamic weight increase being
simultaneously determined; second, liquid metal is fed into a dosing
trough (4, 4') which is located on each side of the intermediate trough
(4, 4') by alternately tilting the intermediate trough (4, 4') on
one side followed by the other. After filling the first dosing trough
(5), the intermediate trough (4) is tilted in the direction of the
second dosing trough (5') while the mass of an anode is cast from
the first filled dosing trough into one of the ingot molds (10, 10')
that are arranged on the casting wheel (9, 9') by means of a controlled
tilting movement. Also disclosed is a device for carrying out the
inventive method.
Claims
1. Method for the exactly weight-controlled filling of ingot molds
of a nonferrous casting machine, for example, a copper anode casting
machine or a zinc anode casting machine, which is designed in the
form of casting wheels for production in a fully mechanized casting
operation and is equipped with ingot molds, wherein, in a first step,
molten metal is introduced into an intermediate trough (4, 4') at
a regulated mass flow rate with simultaneous determination of the
continuous dynamic weight increase, and, in a second step, molten
metal is alternately fed into metering troughs (5, 5') located on
either side of the intermediate trough (4) by tilting the intermediate
trough (4) first to one side and then to the other, and after the
first metering trough (5) has been filled, the intermediate trough
(4) is tilted towards the second metering trough (5'), and at the
same time the mass of an anode is cast from the metering trough that
was filled first into one of the ingot molds (10, 10') located on
the casting wheel (9, 9') by a controlled tilting movement, wherein
the mass flow during casting is divided into preferably three phases,
such that, in a first phase, the casting material is first cast into
an ingot mold at a relatively low mass flow rate; in a second phase,
after a predetermined metal mass or metal weight has been reached,
uniform filling of the ingot mold (10) at a relatively higher mass
flow rate is undertaken; and, in a third phase, after a predetermined
weight of molten metal has again been reached, slow filling at a reduced
mass flow rate is carried out to obtain the precise weight desired.
2. Method in accordance with claim 1, wherein only one metering
trough (5) at a time is alternately filled from the intermediate
trough (4), while the slow, exactly weight-controlled filling of
an ingot mold (10) is being carried out by the other metering trough
(5').
3. Method in accordance with claim 1, wherein, in the case of a
triangular arrangement of the metering troughs (5, 5') on a casting
wheel (9, 9'), only after both metering troughs are filled, are
the next two empty ingot molds (10, 10') brought into position.
4. Method in accordance with claim 1, wherein, in the case of metering
troughs (5, 5') arranged in the form of a Y on two casting wheels
(9, 9'), while the filling operation of one metering trough (5)
is still being performed, the next empty ingot molds (10, 10') are
brought into position under the given presently filled metering
trough (5).
5. Method in accordance with claim 1, wherein the period of time
between the positioning of two ingot molds (10, 10') is calculated
as the so-called cycle time from standing times of a casting wheel
(9, 9') and moving times for positive or negative accelerations,
for example, for filling, inspection, or removal, and overlapping
of the moving times and especially of the filling is taken into
consideration.
6. Casting machine for carrying out casting operations for producing
anodes made of nonferrous metal, such as copper or zinc anodes,
in accordance with claim 1, in which at least one intermediate trough
(4, 4') with outlets (6, 6') that are transversely directed towards
both sides is provided below an outlet of a metal melting furnace
for the limitable admission of molten metal (3), which intermediate
trough, while installed in a stationary way, can be tilted about
its horizontal longitudinal axis (x-x); metering troughs are provided,
which are arranged a vertically projected distance below each outlet
(6, 6') and can tilt about a transverse axis (y-y); and, in addition,
cast iron, copper, or steel ingot molds (10, 10') are provided,
which are arranged on each casting wheel (9, 9') a vertically projected
distance below each casting edge (8, 8') of a metering trough (5,
5'), wherein a stepped casting edge (8, 8') is formed on the front
outlet (7, 7') of each metering trough (5).
7. Casting machine in accordance with claim 6, wherein means, e.g.,
hydraulic cylinders (11, 11'), are provided for tilting each intermediate
trough (4, 4') about its longitudinal axis (x-x); that means, e.g.,
hydraulic cylinders (12, 12'), are provided for tilting each metering
trough (5, 5') about its transverse axis (y-y); that means, e.g.,
weighing cells (13, 13', and 13"), are provided for detecting
the current weight content of the intermediate troughs (4, 4');
and that means, e.g., weighing cells (14, 14', 14"), are provided
for detecting the current weight content of the metering troughs
(5, 5').
Description
[0001] The invention concerns a method for the exactly weight-controlled
filling of ingot molds of a nonferrous casting machine, for example,
a copper anode casting machine or a zinc anode casting machine, which
is designed in the form of casting wheels for production in a fully
mechanized casting operation and is equipped with ingot molds, wherein,
in a first step, molten metal is introduced into an intermediate trough
at a regulated mass flow rate with simultaneous determination of the
continuous dynamic weight increase, and, in a second step, molten
metal is alternately fed into metering troughs located on either side
of the intermediate trough by tilting the intermediate trough first
to one side and then to the other, and after the first metering trough
has been filled, the intermediate trough is tilted towards the second
metering trough, and at the same time the mass of an anode is cast
from the metering trough that was filled first into one of the ingot
molds located on the casting wheel by a controlled tilting movement.
[0002] The invention also concerns a device for carrying out the
method of the invention.
[0003] In contrast to the production of individual castings, for
example, castings produced in relatively small piece numbers in
sand molds, anodes made of nonferrous metals are produced in relatively
large piece numbers in a fully mechanized casting operation with
the use of cast iron, copper, or steel ingot molds that can be used
many times. The features that characterize the desired quality of
the anodes are exact piece weight and exact plane parallelism of
the surfaces of the anodes.
[0004] Constant values of these parameters are achieved in an especially
advantageous way with the use of casting machines equipped with
casting wheels. In this regard, in the peripheral area, for example,
of one or two casting wheels equipped with ingot molds, stationary
opposite casting troughs are provided in a tiltable system, which
are alternately filled with casting metal as the ingot molds pass
beneath them and are then poured out into one of the ingot molds
as it comes to a stop.
[0005] The natural limits of the well-known production process
are set by the speed difference between the stationary casting troughs
and the ingot molds passing beneath these casting troughs with the
casting wheel. The speed difference forces the maximum achievable
output of anode casting according to the weight, quantity, and quality
of the pieces, especially as a function of the necessary standing
time of the casting wheel and the moving times, including the times
required for accelerations and decelerations.
[0006] The cycle time, i.e., the period of time between the positioning
of, for example, two ingot molds, is calculated here from the standing
time of the casting wheel for the purpose of filling, inspection,
and removal, and the moving times, accelerations, and decelerations,
taking into account the fact that there is some overlapping of the
moving times and the filling.
[0007] The document DE 1 956 076 A1 describes a method and equipment
for producing a relatively large number of copper anode plates.
This method uses casting wheels, whose molds are successively filled
with molten copper at a point on the circumference of the wheel
and then further rotated by the distance between two molds. In short
intervals, metered amounts of molten metal are alternately delivered
from a single removal site into at least two casting wheels, so
that one casting wheel is rotated further as long as the casting
operation is occurring at the other casting wheel.
[0008] To achieve exactly weight-controlled casting of copper anode
plates in the individual molds of a casting wheel, it is known from
German Auslegeschrift 2 011 698 that the desired weight of the anode
plates can be determined before the casting metal is poured into
a mold independently of the actual weight of a previously cast anode
plate by weighing out an absolutely adjustable partial amount of
a total amount that is two to three times the partial amount.
[0009] The document JP 55[1980]-084,268 describes a method for
increasing the efficiency of a casting machine with a casting wheel
by the use of two casting positions. In the casting machine, an
intermediate trough, which is provided with transversely directed
outlets, is arranged below an outlet in such a way that it can be
tilted about its horizontal axis. Metering troughs for weighing
the metal are arranged below each outlet of the intermediate trough
and can be tilted about the axis. An ingot mold is arranged below
the outlet of each metering trough.
[0010] The document DE 1 956 076 A1 discloses a method and equipment
for producing a relatively large number of copper anode plates.
In this method, metered amounts of molten metal are alternately
delivered from a single removal site into at least two casting wheels,
so that one casting wheel is rotated further as long as the casting
operation is occurring at another casting wheel or at the other
casting wheel.
[0011] During this operation, the supply of molten metal for metering
is controlled by weighing the total amount on which the metering
is based, and the available amount of molten metal, from which the
partial amount is to be separated, is held constant.
[0012] Proceeding on the basis of the prior art described above,
the objective of the invention is to specify an improved operating
method and an improved design for nonferrous casting machines for
the purpose of increasing the quality of the product and to a achieve
exactly weight-controlled filling of the ingot molds.
[0013] This objective is achieved in a method of the type specified
in the introductory clause of claim 1 by dividing the mass flow
during casting into preferably three phases: In a first phase, the
casting metal is first cast into an ingot mold at a relatively low
mass flow rate; in a second phase, after a predetermined metal mass
or metal weight has been reached, uniform filling of the ingot mold
at a relatively higher mass flow rate is undertaken; and, in a third
phase, after a predetermined weight of molten metal has again been
reached, slow filling at a reduced mass flow rate is carried out
to obtain the precise weight desired.
[0014] The operating method of the invention makes it possible
to guarantee a fully mechanized casting operation with comparatively
high piece numbers with the use of cast iron, copper, or steel ingot
molds that can be reused many times, where the cast anodes have
an exact piece weight and show exact plane parallelism of their
boundary surfaces, i.e., they have those features that characterize
the desired quality of the cast anodes.
[0015] A refinement of the method provides that only one metering
trough at a time is alternately filled from the intermediate trough,
while the slow, exactly weight-controlled filling of an ingot mold
is being carried out by the other metering trough.
[0016] In the case of a triangular arrangement of the metering
troughs on a casting wheel, only after both metering troughs are
filled, are the next two empty ingot molds brought into position.
[0017] In the case of metering troughs arranged in the form of
a Y on two casting wheels, immediately upon completion of the filling
operation of one metering trough, the next empty ingot mold is brought
into position under the given presently filled metering trough.
[0018] In an especially advantageous refinement of the invention,
the period of time between the positioning of two ingot molds is
calculated as the so-called cycle time from standing times of a
casting wheel and moving times for positive or negative acceleration,
for example, for filling, inspection, or removal, and overlapping
of the moving times and especially of the filling is taken into
consideration. Especially overflowing of the melt beyond the tolerances
of the tilting or overflow edges of the ingot molds is avoided in
this way, and plane parallel anode surfaces can be guaranteed.
[0019] Further refinements of the method of the invention are specified
in the dependent claims.
[0020] A casting machine for carrying out casting operations for
the purpose of producing anodes made of nonferrous metal, such as
copper anodes or zinc anodes, in accordance with the introductory
clause of Claim 6 is characterized by the fact that a stepped casting
edge is provided on the front outlet of each metering trough.
[0021] In accordance with a further refinement of the casting machine
in accordance with the invention, it is proposed that means, e.g.,
hydraulic cylinders, be provided for tilting each intermediate trough
about its longitudinal axis; that means, e.g., hydraulic cylinders,
be provided for tilting each metering trough about its transverse
axis; that means, e.g., weighing cells, be provided to detect the
current weight content of the intermediate troughs; and that means,
e.g., weighing cells, be provided to detect the current weight content
of the metering troughs.
[0022] The invention is illustrated in schematic drawings of a
preferred embodiment, which also reveal other advantageous details
of the invention.
[0023] FIG. 1 shows a top view of the casting device of a metal
casting machine with two casting wheels with a V-shaped configuration
of the metering troughs.
[0024] FIG. 2 shows a top view of a casting device with a casting
wheel in a delta-shaped configuration of a pair of metering troughs.
[0025] FIG. 3 shows a rear view of a metering trough.
[0026] FIG. 4 shows a side view of the metering trough in the horizontal
position.
[0027] FIG. 5 shows a side view of a metering trough in its tilted
emptying position.
[0028] FIG. 6 shows an enlarged transverse section of the front
outlet of a metering trough.
[0029] FIG. 7 shows a side view of an intermediate trough with
a swivel bearing.
[0030] FIG. 8 shows a rear view of the intermediate trough with
swivel bearing and swivel drive.
[0031] FIG. 9 shows a perspective view of the casting device.
[0032] The top view of FIG. 1 shows the essential functional elements
of a metal casting machine 9, 9' in functional V-connection of the
metering troughs 5, 5' with an intermediate trough 4. The intermediate
trough can be tilted to either side by means of a rocker bearing
of its axis x-x to empty molten metal into the metering troughs
5, 5' through the outlets 6, 6'. Hydraulic cylinders 12, 12', which
preferably have automatic position control, are installed on one
side of a metering trough as a means for tilting. The intermediate
trough 4 is rotationally supported at two points on a frame 16 to
allow it to swivel about its longitudinal axis x-x, and a hydraulic
cylinder 11 is used as a third mounting point. The frame 16 is also
supported on at least three points on weighing cells 13. The weighing
cells are arranged within the overall system in such a way that
no transverse forces act on the weighing cells and thus no measuring
errors occur.
[0033] The metering troughs 5, 5' are supported by the transverse
axes y-y, so that they can be tilted from the horizontal position
into an emptying position in which they are forwardly inclined.
After the intermediate trough is tilted about the longitudinal axis
x-x, molten metal is poured towards one side through one of the
outlets 6, 6' and into the corresponding metering trough 5, 5'.
[0034] A regulated weight of molten metal is delivered from these
metering troughs into one or the other of the ingot molds 10, 10',
which are provided on the periphery of each casting wheel 9, 9'
and rotate with the casting wheel. During this operation, an amount
of molten metal with an exact weight is delivered by alternately
tilting the intermediate trough 4, 4' to one side and then the other
by means of a lifting cylinder 11. At the same time, an anode is
cast by a controlled tilting movement into one of the ingot molds
10, 10' from the first metering trough 5, 5' to be filled.
[0035] In this first phase, the molten metal is first cast into
an ingot mold at a relatively low mass flow rate to avoid spashing
or overflowing. In a subsequent phase, after a predetermined intermediate
weight has been reached, uniform filling of the ingot molds 10,
10' is carried out at a higher mass flow rate. After a predeterminable
metal casting weight has again been reached at the end of this phase,
slow filling is carried out in a third phase to obtain the precise
weight desired. For this purpose, the point at which the flow of
metal is interrupted is selected in such a way that the predetermined
weight tolerance is maintained. The critical parameters for this
are:
[0036] anode weights;
[0037] different output amounts of molten metal in a metering trough
5; and
[0038] geometry of the metering trough,
[0039] in this regard, the casting edge 8, 8' of the metering trough
5, 5' is designed in such a way that the kinetic energy is reduced
during the tilting operation, and the molten metal flows as vertically
as possible into the ingot mold.
[0040] In this connection, it is advantageous for the casting edge
8, 8' of the metering trough 5, 5' to be designed in such a way
that the kinetic energy of the pouring stream during tilting is
reduced as much as possible, and the molten metal flows as vertically
as possible into the ingot mold, as illustrated in FIG. 5. One metering
trough 5, 5' at a time is alternately filled from the intermediate
trough 4, while the slow, exactly weight-controlled filling of the
first ingot mold 10, 10' is being carried out by the other metering
trough.
[0041] In this operation, the next empty ingot molds 10 are brought
into position only after the two metering troughs 10, 10' are first
filled, and, on the other hand, the next ingot mold is positioned
under the given presently filled metering trough.
[0042] With respect to the positioning, it is important to make
sure that at given positive and negative acceleration states of
the casting wheel 9, 9', the tilting edges of the anodes are maintained
within acceptable tolerance limits, and that the production of plane
parallel anode surfaces is guaranteed.
[0043] The cycle times between the positioning of two ingot molds
are calculated from the standing time of the casting wheel 9, 9',
e.g., for filling, inspection, and removal, and the moving times,
such as positive and negative acceleration, taking into account
the fact that there is some overlapping of the moving times and
the times for the filling.
[0044] The above description must be supplemented by noting that
above the actual casting device 1, a container 3' of any desired
design for holding molten metal 3 is provided, which, when it is
tilted, allows a directed stream of molten metal to flow out into
a feed channel 20, which fills the intermediate trough 4, as FIG.
3 shows. The present weight is monitored by supporting the support
frame(s) 15, or 15 and 16, on the three weighing cells 13. FIG.
4 shows a metering trough 5, 5' with a front pouring spout 7, which
is shown enlarged in FIG. 6. The metering trough 5, 5' in FIG. 4
is supported on the swivel bearing y-y and can be adjusted with
the tilting cylinder 12 into the tilted inclination shown in FIG.
5. FIG. 7 and FIG. 8 show the laterally tiltable intermediate trough
4, 4' from different viewing directions. The same parts in each
of these drawings are labeled with the same reference numbers.
[0045] The method of operation of the casting machine described
above is explained below. The operating method comprises the following
steps:
[0046] (a) An amount of molten metal with a predeterminable weight
is fed from an anode furnace into an intermediate trough 4, 4' of
a casting machine, and the mass flow rate of the molten metal is
controlled by the adjustable opening of a furnace gate. The continuously
determined weight of the dynamically increasing mass of the molten
metal flowing into the intermediate trough 4, 4' is used as the
controlled variable here.
[0047] (b) Molten metal is fed into a pair of metering troughs
5, 5' by tilting the intermediate trough 4, 4' about its longitudinal
axis alternately to both sides by means of, e.g., the tilting cylinder
11. After the first metering trough 5 has been filled according
to the weight program, the intermediate trough 4' is tilted towards
the second metering trough 5', and the predetermined weight of an
anode to be cast is poured into the metering trough 5'. Weighing
devices 13 strictly monitor the mass of the molten metal in the
intermediate trough 4' as well as in the metering troughs, and the
filling of the troughs is automatically controlled in this way.
[0048] The emptying of the metering troughs 5, 5' into one ingot
mold 10 of the casting wheel at a time is effected by raising the
rear end of a metering trough 5 by hydraulic cylinders 12, 12' by
means of automatic position control mechanisms (not shown). This
causes the troughs 5, 5' to be tilted about the axes y-y into an
inclined emptying position.
[0049] The operation of filling the ingot mold from a metering
trough is carried out in three phases:
[0050] Phase (1): Molten metal is first poured relatively slowly,
i.e., at a low mass flow rate, into a given ingot mold. During this
short period of reduced flow, splashing or overflowing of the metal
is avoided, and erosion of the ingot molds is reduced, which prolongs
their service life.
[0051] Phase (2): After a predetermined weight of molten metal
in the associated ingot mold 10 has been reached, uniform filling
is carried out at a higher mass flow rate.
[0052] Phase (3): After a predetermined weight of molten metal
has again been reached in the associated ingot mold 10, slow residual
filling of the associated ingot mold 10 is carried out to obtain
the precise weight desired.
[0053] For this purpose, the point at which the flow of molten
metal is interrupted is selected in such a way that the weight tolerance
is maintained. Dependent process parameters for this are:
[0054] anode weights;
[0055] different output amounts of molten metal in a metering trough
5;
[0056] geometry of the metering trough;
[0057] in this regard, the casting edge 8, 8' of the metering trough
5, 5' is designed in such a way that the kinetic energy is reduced
during the tilting operation, and the molten metal flows as vertically
as possible into the ingot mold.
[0058] One metering trough 5 or 5' at a time is alternately filled
from the intermediate trough 4, 4', while the slow, exactly weight-controlled
filling of an ingot mold is being carried out by the other metering
trough 5'. |