Foaming agent charging and mixing device

• US 20040009250A1
• Filed: 06/16/2003
• Published: 01/15/2004
• Est. Priority Date: 12/15/2000
• Status: Active Grant

• Current Assignee: Sumitomo Demag Plastics Machinery GmbH (Sumitomo Heavy Industries Limited)
• Original Assignee: Demag Ergotech GmbH (Sumitomo Heavy Industries Limited)
• Inventors: Prigandt, Marco, Seidel, Joerg, Schuermann, Erich, Jaeger, Ansgar, Herrmann, Juergen
• Granted Patent: US 7,097,438 B2
• Time in Patent Office: Days
• US Class Current: 425/4R
• CPC Class Codes: B29C 44/0492 Devices for feeding the different materials
• CPC Class Codes: B29C 44/3446 Feeding the blowing agent
• CPC Class Codes: B29C 44/60 Measuring, controlling or regulating
• CPC Class Codes: F16K 11/085 with cylindrical plug

Abstract

A foaming agent charging and mixing device comprises at least one mixing means and one foaming agent metering means, wherein the foaming agent charging and mixing device may be arranged between an plasticating screw and a mold.

In order to improve the foaming agent charging and mixing device in a manner that the mixing with foaming agent is facilitated and at the same time a risk of obstruction of the foaming agent metering means is avoided, the foaming agent metering means is alternately opened and closed through the mixing means during its operation for supplying foaming agent to the plastic melting.

Claims

1. A foaming agent charging and mixing device (1), comprising at least one mixing means (2) and one foaming agent metering means (3), wherein the foaming agent charging and mixing device (1) may be arranged between an plasticating screw (4) and a mold (5),

characterized in that

the foaming agent metering means (3) is alternately opened and closed for supplying foaming agent to the plastic melting.

2. A foaming agent charging and mixing device according to claim 1,

characterized in that

a closing member (19, 54) for alternately opening and closing the foaming agent metering means (3) is assigned to the mixing means.

3. A foaming agent charging and mixing device as claimed in claim 1 or 2,

characterized in that

the foaming agent charging and mixing means is formed as a module, which may be arranged releasably between the plasticating screw (4) and the mold (5).

4. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

the foaming agent metering means (3) comprises at least two inlet bores (6, 22) opening into a device housing, said bores being reciprocally opened and closed by the mixing means (2).

5. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

the foaming agent charging and mixing device extends transversely to the longitudinal direction (7) of the plasticating screw (4), and side openings (9) connectable to a discharge end (8) of the plasticating screw (4) are formed in the device housing (21).

6. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

the device housing (21) comprises at least one collection means (15) for plastic melting.

7. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

the collection means (15) is releasably attached to the device housing (21), wherein the collection means (15) is preferably a piston-cylinder unit (16).

8. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

a channel connection (17) is formed between the side opening (9) and the collection means (15) and/or between the discharge opening (10) and the collections means (15), wherein the mixing means (2) is arranged in the channel connection (17).

9. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

the mixing means (2) comprises at least one mixing shaft (18) and mixing elements (19) outwardly projecting therefrom.

10. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

the foaming agent metering means (3) can be closed by mixing elements (19) and/or closing elements (20) outwardly projecting from the mixing shaft (18) upon rotation of the mixing shaft (18).

11. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

a directional switching means (33) is arranged in the device housing (21), said directional switching means being switchable between a supply directly from the plasticating screw (4) or the collection means (15) to the mold (5).

12. A foaming agent charging and mixing device as claimed in one of the preceding claims,

characterized in that

the foaming agent metering means (3) comprises a reciprocating pump (55), wherein a linear drive in particular having an integrated path measuring system is associated to the reciprocating pump (55).

13. A directional switching means, in particular in a foaming agent charging and mixing device as claimed in one of the preceding claims, which can be switched between a supply of a material from at least two different sources (4, 15) to a consumer (5),

characterized in that

the directional switching means (33) comprises an external body and an internal body (34, 35) rotatably supported therein, wherein an outlet (37) of the external body (34) may be connected to at least one of two inlets (38, 39) of the external body by a connection channel (36) arranged in particular eccentrically in the internal body (35).

14. A directional switching means as claimed in claim 13,

characterized in that

the connection channel (36) extends substantially along an axis of rotation of the cylindrical internal body (35) and comprises a number of branching channels (45, 46, 47, 49, 68), to which at least two outlets and/or inlets in the external body (34) can be assigned by rotation.

15. An injection molding machine for molding foamed plastics having a conventional inline reciprocating plasticizing screw (4) and a conventional clamp or clamping mold (5),

characterized in that

a mixing device (2) is interposed between the clamp and screw, the mixing device having a first inlet (14) in fluid communication with the screw and an outlet (10) in fluid communication with the mold through a shut-off valve (12) and a second inlet (6 and/or 22);

a metering device (3) for pulsing a foaming or blowing agent into the second inlet when the screw is axially translating to inject a set quantity of plastic into the mixing chamber.

16. The infection molding machine of claim 15,

characterized in that

the metering device (3) has kneading elements (19) for mixing the blowing agent into solution with the melt.