EP3117933B1 - Device and method for metering molten material and casting machine - Google Patents

Description

The invention relates to a melt metering device for a casting device, the melt metering device having an evacuable metering container which can be moved between a melt pick-up location and a melt delivery site and which is set up to remove a meterable amount of casting melt material from the melt pick-up location at the melt delivery site of the casting device to be transferred and dispensed there to a melt metering process which can be carried out with such a device and to a casting machine equipped with such a melt metering device. Such devices and methods come e.g. in metal die casting machines for metering the molten metal to be used.

Melt metering devices are known in which pouring melt material is taken up by immersing a spoon or ladle in a melt bath, which is then transferred to a melt delivery site or pouring site in order to deliver the melt material there. The spoon can be manually operated or coupled to a machine transfer unit that operates it. During the transfer, the surface of the melt in the spoon is exposed to atmospheric air.

Alternatively, melt metering systems are in use, in which the melt material is conveyed from the melt bath of a melting furnace into a downwardly inclined transfer pipe by means of a mechanical pump or by pneumatic displacement, in which it flows to the melt delivery point. However, these systems are comparatively complex and the melt material cools down relatively strongly due to the flow along the transfer tube if no corresponding countermeasures are taken.

Further alternatively, melt metering devices of the type mentioned at the outset are known. These contain an evacuable dosing container with an assigned evacuation device. The disclosure JP 2000-218360 A discloses a melt metering device of this type in which the melt opening is formed by a pipe socket which extends both inwards and outwards from the bottom region of the metering container. The the pipe socket half facing inwards is covered by a hood-shaped end end of a hollow pipe which is arranged longitudinally in the middle of the metering container and is connected to an inert gas source. An immersion sensor is arranged on the outside of the container, with which the lowering of the container into the melt bath is monitored until a predeterminable immersion position is reached. The amount of melt material sucked into the dosing container is monitored by means of a weight sensor. As a result, a fill level sensor conventionally provided in the container can be dispensed with.

In the published application JP 2009-039764 A discloses a similar melt metering device of the type with an evacuable metering container, the melt opening of which is likewise formed by a pipe socket which extends both inwardly and outwardly from the bottom of the container. In the device there, the inwardly projecting half of the pipe socket is covered by a hood-shaped front end of an axially movable locking rod. By moving back and forth, the locking rod can be moved between an open position exposing the melt opening and a closed position closing the melt opening at the upper, inner end of the pipe socket. A fill level sensor arranged in the container detects whether melt material sucked into the container has reached a predeterminable fill level. The interior of the container can either be evacuated or an inert gas can be applied. The inwardly facing pipe socket half of the melt opening complicates or prevents devices according to JP 2000-218360 A and JP 2009-039764 A complete emptying of the container at the melt delivery site, even if the container is inclined as described there.

The invention is based on the technical problem of providing a melt metering device of the type mentioned at the outset and a melt metering method which can be carried out by the latter and a casting machine equipped therewith, with which the casting melt material can advantageously be metered out of a melt bath and transferred to a delivery point, with undesirable ones Oxidation effects of the transferred melt material and / or undesired melt losses during the dosing container transport from the melt pick-up point to the melt discharge point can be completely or at least largely avoided.

The invention solves this problem by providing a melt metering device with the features of claim 1, a melt metering method with the features of claim 8 and a casting machine with the features of claim 14. Advantageous further developments of the invention are specified in the subclaims.

The melt metering device according to the invention has an evacuable metering container and an evacuation device for evacuating the metering container. The evacuation of the metering container prevents the pouring melt material received in the metering container from being exposed to atmospheric air or another atmosphere which is disadvantageous for the melt. In this way, the melt material in the evacuated, closed dosing container can be transferred safely and chemically unaffected to the melt delivery point or pouring point. The use of the evacuable and thus inevitably closed dosing container also minimizes heat losses for the melt material being transported, the dosing container optionally being able to be provided with thermal insulation.

Characteristically, the melt metering device according to the invention includes a controllable closure means for selectively opening and closing a melt opening of the metering container, which in its closed position closes the melt opening of the metering container while leaving a capillary opening. The capillary opening is formed by a capillary ring gap between an inner edge of the melt opening and an outer edge of the closure means or by at least one capillary gap groove which is provided on the inner edge of the melt opening or on the outer edge of the closure means. This represents functionally advantageous and simple manufacturing realizations for the capillary opening.

A requirement for the evacuable metering container is often that no melt material drips from the container or leaks out of it on the transport route from the melt pick-up point to the melt discharge point. It has been shown that this requirement is met particularly well with the special closure means which leaves a capillary opening in its closed position and thus does not attempt to seal the melt opening tightly. Thanks to the capillary opening, melt material can be removed after lifting of the dosing container from the melt bath remains in the area of the melt opening, due to the continued evacuation of the inside of the container and the vacuum or suction pressure also acting in the area of the capillary opening, can be held safely and reliably on and in the container without dripping down or away from it to lick out of this.

In a development of the invention, the melt metering device has a special weight sensor which is set up to monitor the weight of the empty dosing container when it is lowered into the melt bath for reaching a predeterminable immersion position of the dosing container. By means of the weight sensor provided in a further development of the invention, the dosing container can be brought safely and reliably into its predeterminable immersion position for receiving melt material from the melt bath, without the need for a separate immersion sensor. The weight sensor uses the effect that the weight of the empty dosing container when immersed in the melt bath is measurably reduced due to the resulting buoyancy. The lighter the dosing container, the more pronounced this effect. This effect can also be influenced by the design of the dosing container in the immersed lower area.

In one embodiment of the invention, the melt opening is provided in a bottom region of the dosing container, and the controllable closure means includes a closure plug which is arranged in the dosing container and can be moved longitudinally. This arrangement has the advantage that the dosing container for receiving melt material only has to be lowered with its base region to the melt bath in order to draw melt through the melt opening from the melt bath into the dosing container. In addition, in order to discharge the melt from the metering container, only the closure means needs to open the melt opening without the metering container having to be moved, for example tilted into an emptying position. The melt opening can easily be designed so that the dosing container is completely emptied without additional measures being required. For this purpose, the melt opening can, for example, at a deepest point of the Container bottom may be provided. In a further embodiment of the invention, the melt opening is formed by a tubular nozzle area protruding outwards from the bottom area of the metering container. The dosing container then does not need to be immersed in its entire width of the base region, but only with its nozzle region in the melt bath in order to suck the melt into the dosing container. The nozzle area can be realized with a comparatively small diameter, as a result of which tearing effects of the melt surface layer of the melt bath can be kept to a minimum.

In a further development of the invention, the melt metering device has a controllable protective gas admission means, through which the metering container can be acted upon in a controllable manner with a customary protective gas, such as e.g. for a protective gas atmosphere in a melting furnace above the melt bath. The shielding gas fulfills its usual shielding gas function for the melt material in the dosing container and can also support the discharge of the melt from the dosing container at the melt delivery point if overpressure is used.

In a further development of the invention, the evacuation device contains a vacuum pump or a piston-cylinder unit which is confirmed in a controlled manner. Both alternatives enable the desired evacuation of the dosing container with relatively little effort.

In a development of the invention, the weight sensor is set up to detect the weight of the filled dosing container as it moves from the melt receiving point to the melt dispensing point and in this way to detect any loss of melt.

In a further development of the invention, the weight sensor is set up to detect the weight of the dosing container during the melt dispensing process in order to be able to recognize whether or when the container is completely emptied.

The method according to the invention is carried out with the melt metering device according to the invention.

In a further development of this method, in order to take up melt material from the melt bath, the dosing container is lowered until the predeterminable immersion position into the melt bath, which is detected by the weight sensor, is lowered and the melt opening closure means is controlled into an open position. An optional protective gas supply can be deactivated and the evacuation device is activated. As a result, melt material is sucked into the dosing container and, if necessary, the protective gas is withdrawn from the dosing container.

In a further development of the invention, the absorption of melt material from the melt bath into the dosing container after a predeterminable period of time has elapsed or when a predeterminable melt filling quantity in the dosing container has been reached, which e.g. can be detected by the weight sensor, the melt opening closure means of the dosing container being controlled into a closed position. This advantageously makes it easy to pick up and transfer a precisely metered amount of melt material from the melt bath to the delivery location.

In one embodiment of the invention, after the absorption of melt material from the melt bath into the metering container has ended, the evacuation device is kept activated with the melt opening closure means kept closed until a melt dispensing process begins. This enables the melt contained in the dosing container to be degassed during its transport to the delivery point. In those embodiments of the invention in which it is provided that the capillary opening remains with the melt opening closed, the melt is also held securely on or in the container by the continued evacuation of the metering container in combination with the capillary opening, which leads to an unintentional loss of melt on the transport path from Prevents the place of admission to the place of delivery.

In a development of the invention, in order to dispense melt material from the metering container, the melt opening closure means is controlled into an open position, and the protective gas is activated. As a result, the melt material can be rapidly removed from the metering container with protective gas overpressure and possibly by gravity.

In a development of the invention, the weight of the metering container is monitored for any loss of melt when moving from the melt receiving location to the melt delivery location and / or for complete emptying during the melt delivery process, for which purpose the weight sensor present in the corresponding embodiments of the invention can be used in particular.

A die casting machine according to the invention is equipped with the melt metering device according to the invention. This can be, in particular, a metal die casting machine, the processed metal material e.g. Can be aluminum, magnesium or zinc.

Fig. 1

eine schematische Ansicht einer Schmelzezudosiervorrichtung mit einem evakuierbaren Dosierbehälter in Längsschnittdarstellung und mit einer Vakuumpumpe als Evakuiereinrichtung,

Fig. 2

eine Darstellung entsprechend Fig. 1 für eine Variante der Schmelzezudosiervorrichtung von Fig. 1 mit einer KolbenZylinder-Einheit als Evakuiereinrichtung,

Fig. 3

eine schematische Schnittansicht eines hier interessierenden Teils einer Metalldruckgießmaschine mit einer Schmelzezudosiervorrichtung nach Art von Fig. 1 oder 2,

Fig. 4

ein schematisches Flussdiagramm eines mit den gezeigten Vorrichtungen durchführbaren Schmelzezudosierverfahrens,

Fig. 5

eine ausschnittweise Schnittansicht eines unteren Teils des Dosierbehälters von Fig. 1 oder 2 in einer Position zum Einsaugen von Schmelzematerial,

Fig. 6

eine Ansicht entsprechend Fig. 4, jedoch mit dem Dosierbehälter in einer Überführposition zwischen Schmelzeaufnahmeort und Schmelzeabgabeort,

Fig. 7

eine Ansicht entsprechend Fig. 4, jedoch mit dem Dosierbehälter in einer Schmelzeabgabeposition,

Fig. 8

eine schematische Längsschnittansicht einer weiteren erfindungsgemäßen Schmelzezudosiervorrichtung, die einen Gewichtssensor beinhaltet,

Fig. 9

eine Ansicht entsprechend Fig. 8 mit der Schmelzezudosiervorrichtung beim Absenken in ein Schmelzebad,

Fig. 10

eine Ansicht entsprechend Fig. 9 mit der Schmelzezudosiervorrichtung beim Befüllvorgang,

Fig. 11

eine Ansicht entsprechend Fig. 10 mit der Schmelzezudosiervorrichtung auf dem Transportweg vom Aufnahmeort zum Abgabeort,

Fig. 12

eine Querschnittansicht längs der Linie XII-XII von Fig. 11,

Fig. 13

eine Querschnittansicht entsprechend Fig. 12 für eine modifizierte Ausführungsform der Erfindung und

Fig. 14

eine Ansicht entsprechend Fig. 11 mit der Schmelzezudosiervorrichtung in Entleerungsposition.

Advantageous embodiments of the invention are shown in the drawings and are described below. Here show:

Fig. 1

2 shows a schematic view of a melt metering device with an evacuable metering container in a longitudinal sectional view and with a vacuum pump as the evacuation device,

Fig. 2

a representation accordingly Fig. 1 for a variant of the melt metering device from Fig. 1 with a piston-cylinder unit as an evacuation device,

Fig. 3

is a schematic sectional view of a part of interest here of a metal die casting machine with a melt metering device of the type of 1 or 2 .

Fig. 4

1 shows a schematic flow diagram of a melt metering method which can be carried out with the devices shown,

Fig. 5

a fragmentary sectional view of a lower part of the metering container of 1 or 2 in a position to suck in melt material,

Fig. 6

a view accordingly Fig. 4 , but with the dosing container in a transfer position between the melting point and the melting point,

Fig. 7

a view accordingly Fig. 4 but with the dosing container in a melt dispensing position,

Fig. 8

2 shows a schematic longitudinal sectional view of a further melt metering device according to the invention, which includes a weight sensor,

Fig. 9

a view accordingly Fig. 8 with the melt metering device when lowering into a melt bath,

Fig. 10

a view accordingly Fig. 9 with the melt metering device during the filling process,

Fig. 11

a view accordingly Fig. 10 with the melt metering device on the transport route from the pick-up location to the delivery location,

Fig. 12

a cross-sectional view taken along the line XII-XII of Fig. 11 .

Fig. 13

a cross-sectional view accordingly Fig. 12 for a modified embodiment of the invention and

Fig. 14

a view accordingly Fig. 11 with the melt metering device in the emptying position.

In the Fig. 1 The melt metering device shown contains, as the melt receiving means, an evacuable metering container 1 with an essentially cylindrical container pot 1 a and a lid 1 b which is placed on the container pot 1 a on the top and is detachably connected to the latter. For this purpose, the container pot 1a has on its upper side an outwardly projecting ring flange 1c, to which the cover 1b is fastened, for example by means of screw connections (not shown), with an annular seal 2 between the pot flange 1c and the lid 1b is inserted. On the cover 1b, an upwardly projecting flange 3 is formed with a suspension opening 3a, through which the dosing container 1 can be pivotally attached to a transfer unit.

The container pot 1a is funnel-shaped in a bottom region 1d with an oblique bottom funnel section, from which a tubular nozzle region 1e protrudes downward, which forms a melt opening 4 of the container 1, via which melt material can be introduced into the container 1 and discharged from it again.

A controllable closure means is assigned to the melt opening 4, which includes a closure plug 5 which is arranged in the metering container 1 and can be moved longitudinally parallel to the longitudinal axis of the container pot 1a. By means of longitudinal movement, as symbolized by a movement arrow P1, the sealing plug 5 can optionally be brought into a closed position or an open position, whereby Fig. 1 shows the sealing plug 5 in its open position which releases the melt opening 4. A corresponding linear drive 6, which is fastened to the container lid 1b, is used to actuate the sealing plug 5.

The dosing container 1 is assigned an evacuation device, which in the example of Fig. 1 includes a vacuum pump 7. The vacuum pump 7 is connected to the interior of the container 1 via a combined vacuum / protective gas line 8.

Furthermore, a protective gas admission means is assigned to the dosing container 1, which contains a protective gas source 9, which is coupled to the combined vacuum / protective gas line 8 via a protective gas line 10. An optional manual shut-off valve 11 and a controllable solenoid valve 12 are provided in the protective gas line 10.

By appropriately activating the vacuum pump 7 or the protective gas application means 9 to 12, an interior 14 of the metering container 1 can optionally be evacuated or a conventional protective gas, for example a nitrogen gas, can be applied to it. A section 8a of the combined vacuum / protective gas line 8 is implemented as a flexible line section, for example in the form of a corresponding piece of hose, in such a way that the metering container 1 remains movable to a corresponding extent with respect to the vacuum pump 7 and the protective gas source 9. The dosing container 1 can thus carry out the desired melt transport movement unhindered from its coupling to the vacuum pump 7 and the protective gas source 9, even if the vacuum pump 7 and the protective gas source 9 are arranged stationary.

The dosing container 1 also has a melt fill level sensor 13 for detecting the melt fill level in the container 1. In the example shown, the fill level sensor 13 is designed as a measuring rod of a type known per se, which is fixed on the container lid 1 b and from there down into the container interior 14 extends. Depending on requirements and sensor design, the melt level sensor 13 continuously detects the fill level of melt material in the container 1 or detects when the melt level has reached or exceeded or fallen below a certain threshold value.

On the outside, a melt bath immersion sensor 15 is arranged on the metering container 1, with which it can be determined whether and / or how deep the container 1 is immersed in a melt bath of a melting furnace for the purpose of absorbing melt material. In the example shown, the sensor 15 is formed by a measuring rod known per se, which is fixed on the outer edge of the container lid 1b outside the container pot 1a, pointing downward. It extends with its sensor part at least down to the level of the pot bottom area 1d or the tubular inlet / outlet nozzle 1e. As a result, he can detect the immersion of the inlet / outlet nozzle 1e in the melt bath.

Fig. 2 shows a variant of the device of Fig. 1 , which differs from this only in the implementation of the evacuation device. Incidentally, the same reference numerals are used for identical or functionally equivalent components, and in this respect it can refer to the above description Fig. 1 to get expelled.

In the embodiment of Fig. 2 The evacuation device includes a piston-cylinder unit 17 with a cylinder 16, a piston 18 guided axially in the cylinder and a piston rod 19 extending from it on one side, which is led out on an end face of the cylinder 16 and with its associated end to a linear drive 20 is coupled. The linear drive 20 allows the piston 18 in the cylinder 16 to be displaced between a fully inserted end position A, shown with solid lines, and a fully extended position C, symbolized by dashed lines, as illustrated by a double arrow P2. A predeterminable intermediate position or central position B, likewise symbolized by dashed lines, is recognized via an associated sensor element 21 functioning as a limit switch element for the linear drive 20. By moving the piston 18 back, the dosing container 1 is evacuated, for example when receiving melt material in the container 1. The piston 18 can be advanced, for example, during the melt dispensing process.

Fig. 3 shows a melt metering device of the type of 1 or 2 in use at a casting facility. In the example shown, the casting device is shown as an example as a metal die casting machine for casting metal parts, for example made of aluminum, magnesium or zinc.

The die casting machine includes, in a manner known per se, a structure 22 for a casting mold, not shown here, with a fixed and a movable mold half, which is actuated by a closing part, also not shown here, and with a melt supply unit, which in the example shown has a casting cylinder arranged horizontally 23 with a melt feed opening 24 at the top and a casting piston 5. The casting plunger 5 is in the casting cylinder 23 between a retracted position which releases the supply opening 24 for the purpose of supplying the melt, as in FIG Fig. 3 shown, and arranged in an advanced position axially movable, wherein the plunger 25 presses a metered amount of molten metal, previously fed into the casting cylinder 23, into the previously closed casting mold by advancing into the advanced end position.

The die casting machine also includes a melting furnace 26, which is arranged at a predetermined distance from the mold structure 22. Also the Melting furnace 26 is of a type known per se with a melting pot 27 for preparing a molten bath 28 of the metal material in question.

The die casting machine is equipped with a melt metering device of the type of 1 or 2 equipped to take a predeterminable, metered amount of metal melt from the melt bath 28 for the respective casting process, to transfer it to the feed opening 24 of the casting cylinder 23 and to dispense it there into the casting cylinder 23. For this purpose, the melt metering device has the metering container 1 and a transfer unit 29, to which the metering container 1 is coupled.

Specifically, the transfer unit 29 in the example shown contains a swivel arm 31 actuated by an associated swivel drive 30, to the free end of which the metering container 1 is articulated via its suspension 3, 3a. The swivel arm 31 executes an approximately semicircular swivel movement symbolized by a dashed curve curve 32 in order to move the metering container 1 between a melting point in the crucible 27, shown with solid lines, and a melt delivery point on the casting cylinder 23, shown with dashed lines. The articulation of the dosing container 1 to the swivel arm 31 is chosen such that the dosing container 1 is, as shown, restrictedly rotatable relative to the swivel arm 31 in such a way that it assumes a vertical position at the melting point in the crucible 27, while at the melting point above the casting cylinder 23 it is like shown slightly inclined relative to its vertical position. This can be accomplished, for example, by a sprocket mechanism with a chain 33 between a drive-side sprocket 34 at the articulated end of the swivel arm 31 and a container-side sprocket 35 on the container linkage at the free end of the swivel arm, the sprockets 34, 35 being designed with a suitably different number of teeth, e.g. that drive-side sprocket 34 with a larger number of teeth than the container-side sprocket 35. With the semicircular swiveling movement of the swivel arm 31, the dosing container 1 then synchronously executes a swiveling movement between its vertical position at the melt receiving location in the crucible 27 and its inclined position at the melt delivery location above the casting cylinder 23.

Below, with additional reference to the flowchart of FIG Fig. 4 and the excerpts from the situation 5 to 7 in more detail on the melt metering process in the metal die casting machine from Fig. 3 received. When the machine is switched off or during waiting breaks, the transfer unit 29 holds the dosing container 1 in a waiting position, step S1 in Fig. 4 , outside the crucible 27 above the melting furnace 26. In this waiting position, the evacuation device 7, 16 to 21 is deactivated.

As soon as a casting operation is requested, the transfer unit 29 lowers the dosing container 1 into the crucible 27 until the immersion sensor 15 detects that the dosing container 1 with its inlet / outlet nozzle 1e is immersed in the melt bath 28. Specifically, the immersion sensor 15 detects that it has reached a bath level 28a of the molten bath 28 with its sensor element lying slightly above the level of the lower edge of the nozzle 1e. The corresponding signal from the immersion sensor 15 is used as a control signal, by means of which the sealing plug 5 is controlled into its open position if it has not already been in the waiting position of the metering container 1, the solenoid valve 9 is closed and the evacuation device 7, 16 to 21 is activated. In this case, the solenoid valve 9 is expediently opened before the dosing container 1 is immersed in the melt bath 28, so that the interior of the container 14 is acted upon by protective gas. In addition, the movement of the swivel arm 31 is stopped by this signal from the immersion sensor 15, that is to say the metering container 1 remains in a melt receiving position according to FIG Fig. 3 , in which he only dips into the melt bath 28 with his nozzle 1e. This has the advantage that the melt surface layer on the bath level 28a is not torn open in a disruptive manner. The disturbance of the melt surface layer accordingly remains minimal and in particular much less than, for example, when immersing a spoon according to the conventional spoon technique mentioned at the beginning.

After completing this container immersion process, step S2 in Fig. 4 , a desired, metered amount of melt is taken from the melt bath 28 into the metering container 1, step S3 in Fig. 4 , For this purpose, as mentioned, the evacuation device 7, 16 to 21 is activated, and the negative pressure which arises in the interior of the container 14 causes melt 37 to pass through the sealing plug 5 released inlet / outlet opening 4 sucked into the container interior 14, as in Fig. 5 illustrated with melt flow arrows 36. As soon as the level of the melt 37 sucked into the container 1 via the nozzle 1e acting as a suction nozzle has reached the lower end of the sensor of the fill level sensor 13, the fill level sensor 13 responds to it and emits a corresponding signal by which the melt absorption process is ended. For this purpose, the sealing plug 5 is moved into its closed position closing the opening 4, in which it closes the melt opening 4 while leaving a capillary opening 4a, as in FIG Fig. 6 indicated. In other words, the sealing plug 5 does not completely close the melt opening 4 in the closed position, but the capillary opening 4a remains between an inner edge 1e 'of the inlet / outlet nozzle 1e and an outer edge 5a of the sealing plug 5. This can be achieved, for example, by the fact that a The outer diameter of the sealing plug 5 is chosen to be slightly smaller by an appropriate capillary dimension than an inner diameter of the inlet / outlet nozzle 1e.

As an alternative to the described function of the melt level sensor 13, the amount of melt to be accommodated in the container 1 can be metered in that a predeterminable time period and / or a predeterminable suction effect of the evacuation device is set for the melt suction process. For example, the sealing plug 5 can be moved back into its closed position after a predeterminable period of time, and / or the suction power of the evacuation device is activated only for a predefinable period of time with a suction power sufficient to suck the melt into the container 1. Furthermore, in the embodiment of Fig. 2 the detection signal of the limit switch element 21 can also be used to control the sealing plug 5 into its closed position when the piston 18 has reached its central position B.

The activity of the evacuation device 7, 16 to 21 is maintained, if necessary with modified suction power. In the device of Fig. 1 this can be done, for example, by switching the vacuum pump 7 to a lower suction quantity or suction power. In the device of Fig. 2 the suction effect for taking up the melt 37 is brought about by moving the piston 18 back from its advanced end position A to the middle position B. This The middle position of the piston 18 is recognized by the limit switch element 21, the detection signal of which then switches the associated linear drive 20 for the piston rod 19 to a lower speed, essentially simultaneously with the closing movement of the sealing plug 5. With its slower further movement from the central position B into its retracted end position C, it stops Piston 18 then maintains a modified suction.

The melt thus sucked into the container 1 in a metered amount is then transferred to the container 1 with the inlet / outlet opening 4 closed and the gas space in the container interior 14 being evacuated via the absorbed melt to the melt delivery point on the casting cylinder 23, step S4 of Fig. 4 , For this purpose, the closed container 1, which contains the absorbed melt 37, is transferred from the melt crucible 27 by the transfer unit 29 and into the melt delivery position on the casting cylinder 23 via its feed opening 24 Fig. 3 pivoted. Fig. 6 shows the metering container 1 in this transfer situation with melt 37 taken in in a metered quantity and inlet / outlet opening 4 closed by the sealing plug 5 while leaving the capillary opening 4a.

By maintaining a certain suction capacity of the evacuation device 7, 16 to 21 as described during the transfer movement of the closed dosing container 1, a desired degassing of the melt 37 contained in the container 1 is advantageously brought about and, at the same time, in cooperation with the capillary opening 4a, the absorbed melt is achieved 37 is held securely in container 1. In particular, the melt 57 is also safely and reliably held in and on the container 1 in the region of the inlet / outlet connector 1e, since the suction effect of the evacuation device 7 is retained there because of the capillary opening 4a, although the sealing plug 5 is in the closed position. Melting material located at the lower edge of the inlet / outlet nozzle 1e is drawn to the capillary opening 4a by the suction effect and therefore remains adhering to the container 1 without undesirably dripping downwards. The capillary dimension of the capillary opening 4a is then suitably designed taking into account the other influencing parameters, such as the shape of the inlet / outlet nozzle, suction pressure and the density and viscosity of the melt material, and is determined for example experimentally.

A melt delivery process can then be carried out, in which the metered quantity of melt 37 from the metering container 1 is filled into the casting cylinder 23 via the feed opening 24 with the casting piston 25 pushed back, see step S5 in FIG Fig. 4 , For this purpose, after the dosing container 1 has reached its dispensing or emptying position above the supply opening 24 of the casting cylinder 23, the sealing plug 5 is again controlled into its retracted open position, in which it releases the inlet / outlet opening 4. In addition, the solenoid valve 12 is opened, thereby reactivating the inert gas in the container interior. At the same time, the evacuation effect of the evacuation device is deactivated. The latter is in the device of Fig. 1 achieved by switching off the vacuum pump 7. In the device of Fig. 2 the piston 18 is held in its retracted end position C. Alternatively, in this case the piston 18 can be moved back into its advanced position A already during the emptying process of the metering container 1. The melt received in the container 1 is therefore emptied via the inlet / outlet opening 4 and the supply opening 24 from the container 1 into the casting cylinder 23 due to gravity and is supported from its rear end position by the application of protective gas under pressure to the container interior 14 and possibly also by the piston feed movement C to its front end position A.

Fig. 7 shows a detail of the dosing container 1 in this emptying position, symbolized by corresponding melt outflow arrows 38. The dosing container 1 is then again ready to carry out a new melt absorption process and is transferred by the transfer unit 29 from its emptying position to the waiting position above the melting furnace 26 or immediately back to its melt reception position in the melting pot 27 pivoted back.

Another advantageous embodiment of the invention is in the 8 to 14 shown. As far as this device has identical or functionally equivalent components as that according to the 1 to 7 the same reference numerals are used for easier understanding, and in this respect it can refer to the above description of the device according to the 1 to 7 including their functionality and benefits. This applies, for example also for leaving the capillary opening 4a between the inlet / outlet nozzle 1e and the sealing plug 5, if the latter is in its closed position which otherwise closes the melt opening 4, as in FIG Fig. 8 shown.

In contrast to the device of 1 to 7 the device of the 8 to 14 additionally has a weight sensor 40, which is arranged between the linear drive 6 of the sealing plug 5, which is realized here as a piston-cylinder unit, and a carrier element 41, via which the dosing container 1 is coupled in this example to a transfer unit (not shown further), which is constructed and Operation, for example, according to the transfer unit 29 Fig. 3 equivalent. In this example, the container pot 1a is held on a housing of the piston-cylinder unit 6 via the container lid 1b. The weight sensor 40, which is also referred to as a weighing cell, conventionally comprises a measuring element for measuring the weight force of the coupled metering container 1 together with the piston-cylinder unit 6 and an evaluation part for evaluating the weight force measurement.

Depending on requirements and application, the sensor evaluation part can be integrated with the measuring element in a common sensor housing or can otherwise be accommodated as hardware and / or software, e.g. as part of a control unit, not shown here, which carries out the various control tasks of the melt metering device. Characteristic functionalities for the weight sensor 40 are implemented in the evaluation part.

A first functionality of the weight sensor 40 is to spend the metering tank 1 for receiving melt from the molten bath 28 in a desired, defined suction or dipping position _A 1, as shown in Fig. 9 corresponding Fig. 5 is shown. For this purpose, after a previous emptying process, the metering container 1 is moved from the melt delivery point back to the melt receiving point and is lowered there onto the melt bath 28. As soon as the dosing container 1 with its inlet / outlet nozzle 1e reaches the melt pool level 28a and dips into the melt pool 28, the melt pool 28 exerts a buoyancy force on the container 1 that is dependent on the immersion depth, which leads to a corresponding reduction in the weight force measured by the weight sensor 40 , With the weight sensor 40, can thereby accurately achieving the optimum dipping position 1 _A to be detected whereupon the Behälterabsenkbewegung is stopped. How out Fig. 9 An optimal immersion position can be seen, for example, in the position in which the molten bath level 28a is located at the upper end of the inlet / outlet nozzle 1e, so that the nozzle 1e is completely immersed in the molten bath 28, while the pot bottom region widening from there 1d is not immersed in the melt bath 28. This minimizes as above Fig. 5 explains faults in the melt surface layer and avoids melt buildup on the container bottom area 1d outside the nozzle area 1e.

After reaching the desired immersion position, the sealing plug 5 is then moved back into its open position and the evacuation device is activated, as in FIG Fig. 10 illustrated by a plug return arrow 42 and evacuation flow arrows 43. As a result, melt 37 is sucked into container 1, as illustrated by the melt flow arrows 36. In a further functionality of the weight sensor 40 monitors during the melt-recording process by measuring the container weight the air sucked into the container 1. amount of melt 37. This may be facilitated in that, after accomplished dipping position _1A of the container 1, a zero adjustment for the weight sensor 40 is carried out, so that it then directly detects the weight of the amount of melt 37 sucked into the container 1.

As soon as it is determined by this functionality of the weight sensor 40 that a predefinable amount of melt 37 has been sucked into the container 1, the suction process is ended by the sealing plug 5, as in FIG Fig. 11 shown, is moved forward into its closed position, as symbolized by a movement arrow 44, and the dosing container 1 is lifted out of the melt bath 28. Subsequently, the dosing container 1 is moved from the melt receiving location to the melt dispensing location, the evacuation filing being kept activated with the same or modified suction power, as above to step S4 of FIG Fig. 4 explained.

As also mentioned above, the sustained evacuation of the filled dosing container 1 in combination with that in the closed position of the sealing plug 5 capillary opening 4a remaining at the melt opening 4 has the desired effect that melt material located in the area of the inlet / outlet connection 1e is held securely in and on the container 1 by the suction / negative pressure also acting in the capillary opening 4a, without going downward therefrom drops. Fig. 12 shows in cross section the capillary opening 4a ₁ formed in this case as a circumferential side between the outer plug wall 5a and the inner pipe wall 1e '. It is formed in that the outer diameter of the sealing plug 5 is chosen to be slightly smaller by a corresponding capillary dimension than the inner diameter of the inlet / outlet nozzle 1e. The optimal capillary width for the desired effect can be determined empirically for the respective application.

Fig. 13 shows an alternative design of the capillary opening 4a in the form of a plurality of capillary grooves 4a ₂ arranged around the circumference, which in this example are provided as axially extending grooves on the inner edge of the inlet / outlet nozzle 1e. It goes without saying that further alternative designs of the capillary opening 4a are possible. Thus, instead of the capillary ring gap 4a ₁ running through the circumference, a capillary ring gap extending only over part of the total circumference can be provided. In other alternative designs, only one capillary groove is provided instead of the capillary grooves 4a ₂ , and / or the at least one capillary groove does not extend exactly axially, but with one component in the circumferential direction. In further alternative designs, one or more capillary grooves are provided on the outer circumference of the sealing plug 5 instead of on the inner edge of the socket 1e, or at least one capillary groove is provided on both the sealing plug 5 and the socket 1e.

In a further implemented functionality, the weight sensor 40 monitors the weight of the filled dosing container 1 during its transport from the melt receiving point to the melt dispensing point. Any dripping or licking of the melt 37 received by the container 1 can thereby be detected.

As soon as the dosing container 1 has reached its melt delivery point above the casting cylinder 23, the emptying process is triggered by, as in Fig. 14 shown, the sealing plug 5 is moved back into its open position, as symbolized by a movement arrow 45, and the evacuation device is switched off and switched to ventilation or protective gas, as symbolized by flow arrows 46. The melt 37 thereby moves rapidly from the container 1 into the casting cylinder 23, as symbolized by the outflow arrows 38. The shape of the container 1 and in particular of its base region 1d including the nozzle 1e enables the container 1 to be completely emptied in its vertical position shown above the casting cylinder 23 without it having to be tilted.

In a further implemented functionality, the weight sensor 40 monitors the complete emptying of the container 1 by monitoring the container weight during the emptying process. As soon as it is recognized by the weight sensor 40 that the weight reduction during the emptying process corresponds to the weight increase during the filling process, it can be concluded that the container 1 has been completely emptied. This monitoring between the aspirated filling quantity and the emptied melt quantity can be used as a plausibility check for quality assurance purposes.

After complete emptying has been recognized, the container 1 can then be moved again to the location where the melt is taken up, the sealing plug 5 preferably being moved back into its closed position and the application of protective gas being able to be ended.

As described above, the device of 8 to 14 monitor the lowering of the dosing container 1 into the melt bath 28 using the weight sensor 40, so that the immersion sensor 15, as it is in the embodiment according to FIGS Figures 1 to 7 is used, can be omitted. In a further alternative embodiment, the lowering of the metering container 1 may be in the molten bath 28 for the purpose of achieving the desired dipping position 1 _A using a pressure measurement monitored or controlled. For this purpose, in this embodiment variant, the container 1 is lowered with the sealing plug 5 moved into its open position and the protective gas supply to the container 1 is kept active. As soon as the container 1 is immersed in the melt bath 28, the one introduced into the interior of the container 14 can Protective gas no longer escape through the melt opening 4, which results in a measurable protective gas pressure increase in the container 1 and the protective gas feed line. This pressure rise can be detected using a protective gas pressure sensor provided for this purpose. The latter then reports that the desired immersion position has been reached, whereupon the application of protective gas is stopped and the evacuation device is activated in order to suck the melt into the container 1. This system design is also suitable for embodiments according to the invention which are not equipped with the weight sensor.

As is clear from the description of the above exemplary embodiments, which are given only by way of example, the invention provides a very advantageous, novel melt metering device with which melt can be transported from a melt bath to a melt delivery point in a precisely metered quantity without air access. The dosing container can be evacuated for this purpose. During the melt transfer, the dosing container can be kept closed and a negative pressure can be maintained in the dosing container. In combination with a capillary opening with the melt opening otherwise closed, this has the effect that the melt can be held securely on and in the container even in the critical area there. The dosing container can have a removal nozzle with a very small cross-section compared to a main part of the container, as a result of which it only needs to be immersed in the melt bath with this inlet nozzle, which minimizes tearing effects on the surface of the melt bath. The evacuation of the dosing container also keeps heat losses low, thermal insulation for the container walls being able to be provided as required, in the embodiments shown e.g. the pot wall and / or the container lid.

One aspect of the invention also provides special advantageous implementations for a weight sensor, with which corresponding melt metering devices are equipped. The weight sensor is used to monitor the weight of the empty dosing container when it is being lowered into the melt bath, which enables a desired, optimal immersion / suction position to be reached in a simple manner without a separate position sensor, for example in the form of a melt bath to be arranged on the outside of the dosing container. Immersion sensor is necessary. Depending on the need and application the weight sensor can be implemented with further functionalities. For example, he can monitor the container weight while the dosing container is being transported from the melt pick-up location to the melt release location in order to be able to determine whether the melt is dripping from the container or leaking out of it undesirably. In another implementation, the weight sensor can monitor the container weight during the melt suction process to detect when the desired amount of melt has been sucked into the container and then stop the melt absorption process. In yet another implementation, the weight sensor can be used to monitor the container weight during the emptying process to determine if the container has been completely emptied. It goes without saying that, depending on requirements, only some of these functionalities need to be implemented for the weight sensor.

In the Figures 1 to 7 is an embodiment of the invention without a weight sensor, but shown with a capillary opening in the Figures 8 to 14 An embodiment is shown that has both the weight sensor and the capillary opening. It goes without saying that the invention also includes embodiments which only have the weight sensor in corresponding implementations, but not the capillary opening on the otherwise closed melt opening.

The melt metering device according to the invention can be used not only for the explicitly shown case of metal die casting machines, but also for any other casting devices in which melt is to be transferred from a melt bath that is physically distant to a melt delivery site or casting site, such as, for example, also in die casting plants. The melt metering device according to the invention is very easy to adapt to existing casting units and melting furnaces, so that existing plants can be retrofitted with it without any problems. Larger bath level fluctuations in the melting crucible of the melting furnace are also no problem for the melt metering device according to the invention. The dosing container is simply lowered into the melting crucible until it is detected that the container dips into the melt bath with its inlet nozzle. The transfer unit for the dosing container can be kept structurally simple and, if required, requires only a single drive. With the melt metering device according to the invention Any conventional melting materials can be transferred, especially metallic melts such as for aluminum, magnesium and zinc casting.

Claims (14)

1. Molten material metering device for a casting device, comprising

   - a metering container (1), which can be evacuated and moved between a melt uptake point and a melt discharge point, configured to take out a meterable amount of casting molten material from a melt bath at the melt uptake point, to transfer the molten material to the melt discharge point of the casting device and to discharge it there,

   - an evacuation device (7, 17), which is coupled to the metering container for evacuation of the same, and

   - a controllable closure means (5, 6) for selectively opening and closing of a melt opening (4) of the metering container (1),

   characterized in that

   - the closure means in its blocking position blocks the melt opening of the metering container while leaving a capillary opening (4a), which capillary opening is formed by a capillary annular gap (4a₁) between an inner edge (1e') of the melt opening and an outer edge (5a) of the closure means or by at least one capillary gap groove (4a₂) which is provided at the inner edge of the melt opening or at the outer edge of the closure means.
2. Molten material metering device according to claim 1, further characterized in that the controllable closure means includes a closure plug (5) arranged longitudinally movable in the metering container and in that the melt opening is provided in a bottom region (1d) of the metering container.
3. Molten material metering device according to claim 2, further characterized in that the melt opening is formed by a pipe-shaped socket region (1e) projecting from the bottom region of the metering container in the outward direction.
4. Molten material metering device according to claim 2 or 3, further characterized by a weight sensor (40), which is configured to monitor the weight of the empty metering container during lowering into the melt bath with respect to reaching a predefinable submerged position (1_A) of the metering container, and is arranged between a linear drive (6) of the closure plug, configured as piston-cylinder unit, and a support element (41), by which the metering container is coupled to a transfer unit of the molten material metering device, wherein a container pot (1a) of the metering container is held to a housing of the piston-cylinder unit by a container cover (1b) of the metering container.
5. Molten material metering device according to any one of claims 1 to 4, further characterized by a controllable inert gas charging means (9 to 12) for controllably charging the metering container with an inert gas.
6. Molten material metering device according to any one of claims 1 to 5, further characterized in that the evacuation device includes a vacuum pump (7) or a controllably actuated piston-cylinder unit (17).
7. Molten material metering device according to any one of claims 2 to 6, further characterized in that the weight sensor is configured to monitor the weight of the filled metering container during movement of the same from the melt uptake point to the melt discharge point with respect to melt loss and/or to monitor the weight of the metering container with respect to complete draining during the melt discharge procedure.
8. Method for metering molten material for a casting machine, characterized in that for conducting the method, a molten material metering device according to any of the claims 1 to 7 is used.
9. Method according to claim 8, further characterized in that for taking-up molten material from the melt bath, the metering container is lowered into the melt bath until reaching the predefinable submerged position detected by means of the weight sensor, the closure means is actuated into an open position and the evacuation device is activated.
10. Method according to claim 8 or 9, further characterized in that the uptake of molten material from the melt bath into the metering container is terminated after expiry of a predefinable time period or when reaching a predefinable, detected melt filling level in the metering container, wherein the closure means is actuated into its blocking position.
11. Method according to any one of claims 8 to 10, further characterized in that the evacuation device is kept activated after completed uptake of molten material from the melt bath into the metering container, while the closure means is kept closed, until a melt discharge procedure begins.
12. Method according to any one of claims 8 to 11, further characterized in that for discharging molten material from the metering container, the closure means is actuated into an open position and the inert gas charging is activated.
13. Method according to any one of claims 8 to 12, further characterized in that the metering container is monitored with respect to melt loss by detecting its weight when moving from the melt uptake point to the melt discharge point and/or with respect to a complete draining during the melt discharge procedure.
14. Pressure die casting machine, preferably a metal pressure die casting machine, characterized in that it comprises a molten material metering device according to any one of claims 1 to 7.

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