EP1795283A1 - Device for charging foundry machines with metal melt - Google Patents

Abstract

Device for charging a casting device with a metal melt comprises a melt conveying unit with an outlet tube having an downwardly directed tubular section (10a) and an upwardly directed tubular section (10b).

Description

The invention relates to a device according to the preamble of claim 1 for feeding a casting device with a casting melt.

Such devices are used, for example, for charging cold chamber die casting machines with molten metals, such as aluminum or magnesium melts. The casting melt, i. The material to be cast is melted in the crucible and transported from this batch in metered quantity via the outlet pipe to the casting device or a melt feed opening thereof.

In a conventional type of charging device, the outlet pipe is led out of the crucible as a more or less straight, obliquely downwardly extending piece of pipe directly on a side wall of the crucible. In another conventional type Feeding the outlet pipe is led out with a vertically or obliquely upwardly facing riser section from the crucible. For this purpose, it is known that the outlet pipe is formed solely by this riser section, ie this is provided with the end-side outlet opening, or this is followed by a substantially horizontal or obliquely downwardly pointing pipe section having the outlet end of the outlet. Representative of this state of the art are the publications JP 08-033971 A . JP 2002-144013 A . DE 2 111 462 and EP 1 486 277 A1 and the patents DE 1 134 183 and EP 0 817 691 B1 called.

A known problem of such feeders is undesirable environmental gas influences to which the molten casting is subjected at its surface in the outlet pipe area. As a remedy, it is known to introduce a protective gas in the outlet pipe area, e.g. an oxygen-free protective gas which protects against oxidation of a metal melt material, see also the publications cited above.

The invention is based on the technical problem of providing a feeding device of the type mentioned, which allows a good protection of the casting melt in the outlet pipe area with relatively little effort.

The invention solves this problem by providing a charging device having the features of claim 1. In this charging device, the discharge pipe in the melt conveying direction, following a downwardly pointing pipe section, comprises an upwardly facing pipe section. This has the consequence that, between the individual batchwise charging processes, molten casting is at least in this transition region from the downwardly pointing and upward-pointing pipe section and possibly substantially in the entire region of the downward and upward-pointing pipe section remains. As a result, the casting melt is exposed to a gas environment only with a comparatively small surface during a charging process as well as between the individual charging processes. This accordingly minimizes any undesirable effects of a surrounding gas atmosphere on the casting melt in addition to optional further protective measures such as the introduction of an inert gas.

In one embodiment of the invention according to claim 2, the downwardly facing and upstream in the melt conveying direction, upwardly facing pipe section in a kinked or V-shaped or arcuate or U-shaped to each other. In both, structurally simple to implement cases results in the desired manner, a siphon-like region of the outlet pipe, in which melt material remains between the individual feed operations. In the subsequent charging process, it is immediately available in the outlet pipe and does not need to be supplied while displacing a gas atmosphere otherwise present there, so that the free surface of the melt material exposed to the gas atmosphere in the outlet pipe is minimized even during the charging process.

In a further development of the invention according to claim 3 is followed by the upwardly facing pipe section, the outlet opening of the outlet pipe, i. the casting melt passes during the loading process directly from this upwardly facing pipe section into the pouring device.

In an advantageous development of the invention according to claim 4, the outlet pipe is designed such that its outlet opening is at or above the lowest level of the top of the inner wall of the outlet pipe at its transition from the downwardly facing to the subsequent, upwardly facing pipe section. This ensures that on and after completion of a loading operation, the upwardly facing pipe section remains substantially completely filled with molten casting.

In an advantageous development of the invention according to claim 5, the outlet pipe in front of the downwardly facing pipe section comprises a riser section, which may be of conventional form per se, to lead the casting melt upwards out of the crucible. The riser section is associated with a metering pump unit in a conventional manner. In an advantageous embodiment, according to claim 6, the outlet pipe is formed so that its outlet opening is at or above the level of the transition from the riser to the downstream in the melt conveying direction, downwardly facing pipe section. This ensures that the discharge pipe always remains substantially completely filled with melt material from the riser section to its outlet opening during and between the charging operations.

Fig. 1

eine schematische Schnittansicht einer herkömmlichen Beschickungsvorrichtung im Stillstand,

Fig. 2

eine Ansicht entsprechend Fig. 1 während eines Beschickungsvorgangs,

Fig. 3

eine schematische Schnittansicht einer erfindungsgemäßen Beschickungsvorrichtung im Stillstand und

Fig. 4

eine Ansicht entsprechend Fig. 3 während eines Beschickungsvorgangs.

Advantageous embodiments of the invention and their better understanding received conventional embodiments are illustrated in the drawings and described below. Hereby show:

Fig. 1

a schematic sectional view of a conventional charging device at a standstill,

Fig. 2

a view corresponding to FIG. 1 during a loading process,

Fig. 3

a schematic sectional view of a feed device according to the invention at a standstill and

Fig. 4

a view corresponding to FIG. 3 during a loading process.

1 and 2 illustrate a conventional apparatus for feeding a casting device with a casting melt 1, in particular a molten metal such as magnesium, which is melted in a crucible 2, wherein the melt level 1 a in the crucible 2 is maintained at a desired level. In the crucible 2, a metering pump unit 3 is inserted from above. It is eg of one in the above mentioned EP 1 486 277 A1 type described, to which reference may be made for further details. In particular, the metering pump unit 3 has a pump tube 4, which is provided with a drivable mechanical pump part 6 at its lower area immersed in the melt 1. On the protruding from the crucible 2, the upper end of the pump tube 4, an associated pump drive motor 5 is attached, from which a drive shaft 7 extends to the mechanical pumping part 6.

The pump tube 4 is at its lower end via a U-shaped connecting tube 8 with a riser 9 in fluid communication, which also extends parallel to the pump tube 4 also substantially vertically. The riser 9 forms a substantially vertical riser portion of an outlet pipe, which further comprises a laterally on the riser 9 ausmündenden, straight obliquely downwardly extending pipe section 10. At the lower end of this downwardly facing pipe section 10, a drain cock 11 is attached, which forms the end outlet opening of the outlet pipe and is positioned for feeding a pouring device in a suitable manner over a filling opening of a pouring device, not shown. For this purpose, the outlet pipe with its riser section 9 is preferably held rotatably in a bearing 12, which can be mounted in a manner not shown on a lid, not shown, of the crucible 2. The spout is essentially provided over its entire length outside the crucible 2 with a sufficient thermal insulation 13, in which optionally also a heating, such as by electric heating wires 14, may be integrated.

In order to protect the molten metal 1 during the loading operations against undesirable influences of the surrounding gas atmosphere in the outlet pipe 9, 10, the outlet pipe 9, 10 with a suitable, e.g. oxygen-free inert gas 15 are filled, for which purpose suitable inlet / outlet openings 16, 17 are provided on an upper end face of the riser 9 and / or the drain cock 11.

In this conventional construction, the outlet pipe 9, 10 with switched dosing pump unit 3, ie between two feed operations, emptied over its entire length from the riser 9 above the melt level 1 a and the downwardly facing pipe section 10 to the end outlet opening of the outlet tap 11 of the melt material 1 and filled with inert gas 15, as shown in FIG. 1 can be seen. Upon activation of a charging process with appropriate turning on the metering pump unit 3, the melt 1 is pumped up the riser 9 to the branch of the subsequent downwardly facing pipe section 10 and then runs in the downwardly facing pipe section 10 down to fed via the outlet cock 11 of the pouring device be, as illustrated in Fig. 2 by corresponding flow arrows S. In this case, the outflowing melt 1 corresponding to inert gas displaced from the outlet pipe 9, 10, and due to this construction of the outlet pipe 9, 10 does not fill the entire cross section of the downwardly facing pipe section 10, but only a lower part thereof. Thus, during the charging operation, the melt 1 remains in contact with the overlying gas atmosphere over the entire length of the downwardly facing pipe section 10 on its surface. This large surface contact the Melt 1 to the surrounding gas atmosphere can lead to undesirable effects even when using the protective gas 15, for example due to impurities or residual oxygen content thereof.

The invention addresses this problem by a different outlet pipe construction, as will become apparent from the embodiment shown in FIGS. 3 and 4. As far as the loading device of Figs. 3 and 4 identical or at least functionally equivalent elements as the conventional embodiment of FIGS. 1 and 2, these are provided for ease of understanding with the same reference numerals, and it can in this respect to the above explanations to Figs 2 be referenced. This relates in particular to the design of the crucible 2 and the metering pump unit 3.

The charging device according to the invention of Fig. 3 and 4 has an outlet pipe configuration, which consists of the riser 9 according to the charging device of Fig. 1 and 2, a laterally opening out obliquely downwardly extending pipe section 10a and a latter in the melt conveying direction at a transition 18 kinkförmig subsequent, obliquely upwardly extending pipe section 10b composed, whose outlet-side end is provided with a the end-side outlet opening of the outlet pipe forming drainage tap 11a. In this case, the heat-insulating tube casing 13 is seamlessly continued from the downwardly facing pipe section 10a to the upward-facing pipe section 10b to close to the outlet tap 11a. Depending on requirements, a heating device, such as by the electric heating wires 14, only in the riser section 9, as shown, or alternatively or additionally in the region of the downwardly facing pipe section 10a and / or the upward-facing pipe section 10b integrated into the heat insulation 13 or separately this be provided.

By this construction of the spout 9, 10a, 10b, the downwardly facing tube portion 10a and the subsequent upwardly facing tube portion 10b remain substantially complete, both during the loading operations and between two loading operations, i. over its full tube cross-section and practically its entire length, filled with the melt 1, as shown in Figs. 3 and 4 illustrated.

Specifically, the outlet tube construction according to FIGS. 3 and 4 is selected so that the outlet nozzle 11a defined level N _{A of} the outlet end outlet of the discharge pipe is at or above the level N _{S of} the transition from the riser section 9 to the downwardly facing pipe section 10 a, the latter due to the obliquely downward course of the pipe section 10a above the level N _{T of} the top of the pipe inner wall at the transition 18 from the downwardly facing pipe section 10a to the upward-facing pipe section 10b. As a result, between the charging processes, ie when the metering pump unit 3 is switched off, as shown in FIG. 3, the melt 1 remains in the downwardly pointing pipe section 10a and in the upward-pointing pipe section 10b up to a level N _M which corresponds to the level N _S the transition from the riser section 9 to the downwardly facing pipe section 10a corresponds. The downwardly pointing pipe section 10a and the upward-pointing pipe section 10b remain substantially completely filled with the melt 1 up to this melt level N _M , so that the melt 1 there only with a relatively small surface portion in the transition region of riser section 9 and downwardly facing pipe section 10a and in the outlet tap area an overlying gas atmosphere, eg inert gas atmosphere is exposed.

Upon activation of a charging process then, as illustrated in Fig. 4 with corresponding flow arrows S, melt 1 from pumped from the crucible 2 via the mechanical pumping part 6 and the deflection 8 upwards into the riser section 9 and from there into the downwardly facing pipe section 10a to already there melt 1. Once the pump level N _P , ie the pumped melt level N _M , im Rising section 9 has reached the outlet level N _A , the melt 1 flows through the outlet cock 11 a in the pouring device, not shown. Thus, as in the example shown in Figs. 3 and 4, when the outlet level N _{A is} at or above the level of the top of the lateral orifice from the riser section 9 into the downwardly facing pipe section 10a, the downwardly facing pipe section 10a is as well as the upwardly facing pipe section 10b completely filled with melt 1 during the charging process. The melt 1 thereby has contact with the overlying gas atmosphere during the charging process only with the cross section of the riser section 9 and a free surface in the outlet cock 11a. This means a drastic reduction in the contact area of the melt 1 with the overlying gas atmosphere during the batch feed operations.

It is understood that this gas contact reducing effect for the melt can be achieved not only in the specific embodiment of FIGS. 3 and 4, but also for further corresponding embodiments of the invention. Thus, in modified embodiments of the invention, a U-shaped or arcuate transition is provided instead of the crescent-shaped or V-shaped transition 18 from the downwardly directed pipe section 10a to the upwardly directed pipe section 10b. In further embodiments of the invention, the downwardly pointing pipe section, which is followed by the upward-pointing pipe section, is guided out of the crucible directly laterally, with the elimination of the riser section.

Furthermore, the invention includes embodiments in which the outlet pipe in addition to the downwardly facing and then upwardly facing pipe section still includes one or more other, upwardly and / or downwardly directed pipe sections. The characterizations "downwards" and "upward" are to be understood here as including both the possibility of a vertical and an oblique course of the relevant pipe section. It is essential in each case that remains through the design of the outlet pipe with the downwardly facing pipe section and the adjoining, upwardly facing pipe section melt at least in the transition region of these two pipe sections between the individual feed operations and thereby the free surface of the melt at which this with an overlying Gas atmosphere comes into contact, at the beginning and in the course of each feed process remains relatively small. This prevents from the outset appropriate interference by the overlying gas atmosphere, regardless of whether it is a normal ambient gas or a protective gas atmosphere.

Claims (6)

Apparatus for feeding a casting device with a casting melt, in particular a molten metal, with a crucible (2) and a discharge pipe leading out of the crucible with a plurality of pipe sections (9, 10a, 10b),
characterized in that - The outlet pipe in the melt conveying direction subsequent to a downwardly facing pipe section (10 a) comprises an upwardly facing pipe section (10 b). Apparatus according to claim 1, further characterized in that the upwardly facing pipe section and the downwardly facing pipe section in a V-shaped or U-shaped connection to each other. Apparatus according to claim 1 or 2, further characterized in that an end-side outlet opening of the outlet pipe is provided at the end of the upwardly facing pipe section. Apparatus according to claim 3, further characterized in that the level (N _A ) of the outlet end outlet of the discharge pipe is at or above the lowest level (N _T ) of an inner wall top of the discharge pipe in the connecting region of the downwardly facing pipe section to the upwardly facing pipe section. Device according to one of claims 1 to 4, further characterized in that the outlet pipe a riser section (9) comprises, which leads out of the crucible (1) upwards and is coupled on the inlet side to a metering pump unit (3), wherein the downwardly facing pipe section (10a) opens out of the riser section. Apparatus according to claim 5, further characterized in that the level (N _A ) of an end outlet opening of the outlet pipe at or above the level (N _S ) of the outlet pipe at the transition from the riser section to the subsequent, downwardly facing pipe section.

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