PLASTICIZING UNIT AND/OR AN INJECTION UNIT FOR A MOLDING MACHINE

Abstract

A plasticizing unit and/or injection unit for a molding machine with an injection cylinder for plasticized material, at least one degassing opening, and a degassing device in flow connection with the at least one degassing opening for releasing and discharging undesired gases from the plasticized material. The degassing device has a flow element, in flow connection with the at least one degassing opening, which is formed to generate a negative pressure by the Venturi effect at the degassing opening, and/or the degassing device has a filter device, in flow connection with the at least one degassing opening, for filtering gases being released.

Claims

1. A plasticizing unit and/or injection unit for a molding machine with an injection cylinder for plasticized material, at least one degassing opening and a degassing device, in flow connection with the at least one degassing opening, for releasing and discharging undesired gases from the plasticized material, wherein: the degassing device has a flow element, in flow connection with the at least one degassing opening, which is formed to generate a negative pressure by means of the Venturi effect at the degassing opening, and/or the degassing device has a filter device, in flow connection with the at least one degassing opening, for filtering gases being released.

2. The plasticizing unit and/or injection unit according to claim 1, wherein the flow element and/or the filter device is formed as part of a closed flow loop.

3. The plasticizing unit and/or injection unit according to claim 1, wherein the flow element and/or the filter device is in flow connection with at least one conveyorpreferably a fan, compressor or compactor.

4. The plasticizing unit and/or injection unit according to claim 1, wherein the flow element is in flow connection with the filter device.

5. The plasticizing unit and/or injection unit according to claim 1, wherein the flow element is formed to be flowed through by a carrier medium to generate the Venturi effect, preferably with a predetermined pressure and/or a predetermined flow rate, with the result that the gases discharged through the at least one degassing opening are taken up in the carrier medium and/or carried by it.

6. The plasticizing unit and/or injection unit according to claim 1, wherein at least one supply device for a carrier medium is provided, which is formed to bring the gases discharged through the degassing opening into contact with the carrier medium, with the result that the discharged gases are taken up in the carrier medium and/or carried by it.

7. The plasticizing unit and/or injection unit according to claim 5, wherein the flow element and/or the filter device is in flow connection with at least one cooling device, which cooling device is formed to cool the gases escaping through the at least one degassing opening, and preferably the carrier medium.

8. The plasticizing unit and/or injection unit according to claim 1, wherein a rotatably mounted, and preferably linearly displaceable, plasticizing screw is arranged in the injection cylinder.

9. The plasticizing unit and/or injection unit according to claim 8, wherein the at least one degassing opening is arranged in a region of the plasticizing screw, preferably in a region of the plasticizing zone of the plasticizing screw.

10. The plasticizing unit and/or injection unit according to claim 1, wherein a distance of the flow element from the at least one degassing opening is smaller than 5 times, preferably 3 times, a reference quantity, wherein the reference quantity is a screw diameter and/or a characteristic quantity of the degassing opening, wherein the flow element is particularly preferably arranged directly at the at least one degassing opening.

11. The plasticizing unit and/or injection unit according to claim 1, wherein the flow element has a Venturi nozzle.

12. The plasticizing unit and/or injection unit according to claim 1, wherein the filter device has a separation device, preferably a cyclone separator.

13. A molding machine with a plasticizing unit and/or injection unit according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Further examples, advantages, and details of the invention are represented in the figures and the following description of the figures, in which:

[0068] FIG. 1 shows a first embodiment of a plasticizing and injection unit,

[0069] FIG. 2 is a detail view of FIG. 1, and

[0070] FIG. 3 shows a molding machine with a plasticizing unit and an injection unit.

DETAILED DESCRIPTION OF THE INVENTION

[0071] FIG. 1 shows a first embodiment of a plasticizing unit 1 and an injection unit 2, wherein the plasticizing unit 1 and injection unit 2 shown are formed in two stages.

[0072] Such a plasticizing unit 1 and injection unit 2 is in most cases used in compounding or recycling applications, wherein a contaminated material to be plasticized is first supplied to a second injection cylinder 20 of a plasticizing unit 1 via the supply device 16.

[0073] After the material to be plasticized has been supplied via the supply device 16, the material to be plasticized is plasticized in the second injection cylinder 20 via the rotationally mounted second plasticizing screw 19.

[0074] The shearing generated by the plasticizing screw 19, shear heat and the external heat supplied via the heater bands 18 results in the plasticizing, whereby the material to be plasticized is plasticized.

[0075] After the plasticizing by the second plasticizing screw 19, the plasticized material is supplied to the injection cylinder 4 via the molten material line 17.

[0076] The injection cylinder 4 has a rotationally and linearly movable plasticizing screw 13 (often also referred to as an injection screw), which is mounted in the injection cylinder 4.

[0077] The plasticized material from the molten material line 17 entering via the supply opening 21 is further plasticized by this plasticizing screw 13 and conveyed in the direction of the tip of the plasticizing screw 13.

[0078] At the tip of the plasticizing screw 13, the plasticized material accumulates in the space in front of the screw 22, wherein the plasticized material is conveyed via the nonreturn valve 33.

[0079] This plasticizing process is performed until a desired quantity of plasticized material has accumulated in the space in front of the screw 22.

[0080] As soon as the desired quantity of plasticized material has accumulated in the space in front of the screw 22, the plasticizing screw 13 is moved linearly in the direction of the space in front of the screw 22, whereby the nonreturn valve 33 closes and a pressure is exerted on the plasticized material in the space in front of the screw 22.

[0081] An injection nozzle opening 23 is opened (actively or passively), with the result that the plasticized material can be supplied to the mold 24 (represented dashed here) via the injection nozzle opening 23 via the pressure exerted on the plasticized material in the space in front of the screw 22 and due to the linear movement of the plasticizing screw 13.

[0082] Once the plasticized material supplied into the mold 24 has been pushed out of the injection cylinder 4 by the plasticizing screw 13, this plasticized material cools down in the mold 24 and solidifies to form a molded component, which can then be taken out of the mold 24.

[0083] After the injection of the plasticized material from the space in front of the screw 22, the injection nozzle opening 23 is closed again and the plasticizing screw 13 again begins a rotational movement for plasticizing and conveying the plasticized material from the supply opening 21 via the nonreturn valve 33 into the space in front of the screw 22.

[0084] The plasticizing unit 1 and injection unit 2 of this embodiment has a degassing device 6.

[0085] This degassing device 6 is represented in more detail enlarged in FIG. 2.

[0086] The degassing device 6 branches off from a degassing opening 5 from the injection cylinder 4, which degassing opening 5 is arranged on a side of the supply opening 21, facing away from the injection nozzle opening 23, in the lateral surface of the injection cylinder 4.

[0087] This degassing opening 5 connects the interior of the injection cylinder 4 to the flow element 7, wherein the flow element 7 is formed to generate a negative pressure by means of the Venturi effect at the degassing opening 5.

[0088] The flow element 7 of this embodiment is formed as a Venturi nozzle 14, as can be seen in more detail in FIG. 2.

[0089] This Venturi nozzle 14 is flowed through by a carrier medium, which is conveyed in the flow loop 9.

[0090] In the present embodiment, the carrier medium is steam.

[0091] As a result of the flow of the carrier medium through the Venturi nozzle 14, a negative pressure is generated at the degassing opening 5, which has the result that the degassing device 6 releases and discharges undesired gases from the plasticized material in the injection cylinder 4.

[0092] The discharged, undesired gases from the plasticized material are mixed with the carrier medium in the Venturi nozzle 14 and supplied to a filter device 8 via the flow loop 9.

[0093] This filter device 8 is formed by a cyclone separator 15, whereby the undesired gases from the plasticized material can again be separated from the carrier medium and remain behind in the filter device 8, while the carrier medium is supplied back to the flow element 7 (the Venturi nozzle 14) via the conveyor 10, passes through this flow element 7 again, takes up undesired gases and supplies them to the filter device 8 again.

[0094] The degassing device 6 furthermore has a cooling device 12, which in this embodiment is connected upstream of the cyclone separator 15 in the flow direction and is formed to cool the carrier medium together with the discharged undesired gas before it reaches the cyclone separator 15.

[0095] Due to the cooling of the carrier medium together with the discharged undesired gas by the cooling device 12, the undesired gas subsequently supplied to the cyclone separator 15 is cooled together with the carrier medium, whereby certain constituentspreferably all of the undesired gasbehave unlike the carrier medium due to their material properties, optionally condense, and can thus be separated more effectively from the carrier medium by the cyclone separator 15.

[0096] The cyclone separator 15 represented in FIGS. 1 and 2 is to be understood merely as a purely schematic representation.

[0097] The carrier medium purged of the undesired gas can then be supplied to the flow loop 9 again, whereas the, preferably condensed, undesired gas or constituents thereof remain in the cyclone separator 15.

[0098] It can be provided that the cyclone separator 15 has a discharge device, which is formed to discharge the substances separated from the carrier medium from the cyclone separator 15.

[0099] The conveyor 10 of this embodiment has a compactor 11, which moves the carrier medium through the flow loop 9 according to the arrows drawn in and supplies it to the Venturi nozzle 14.

[0100] FIG. 3 shows a molding machine 3 with a plasticizing unit 1 and an injection unit 2.

[0101] A molding machine 3 is represented schematically in FIG. 3. This molding machine 3 has a plasticizing unit 1 and a clamping unit 28, which are arranged together on a machine frame 28.

[0102] The clamping unit 28 has a fixed platen 27, a movable platen 26 and an end plate 25.

[0103] In contrast to the horizontal three-plate machine represented, the clamping unit 28 could also be formed as a two-plate machine or as a vertical machine.

[0104] The movable platen 26 is movable relative to the machine frame 29 via a drive device 30. Such a drive device 30 can have for example a knuckle joint mechanism.

[0105] Mold halves of a mold 24 can be clamped or fitted (represented dashed) on the fixed platen 27 and the movable platen 26.

[0106] The mold 24 represented closed in FIG. 3 has at least one cavity. An injection channel, via which a plasticized material can be supplied to the plasticizing unit 1, leads to the cavity.

[0107] The plasticizing unit 1 has a continuous plasticizing unit 34, which is formed as a single-screw extruder and via which a recycling material can be supplied.

[0108] This continuous plasticizing unit 34 plasticizes the material to be plasticized and further channels the plasticized material via the molten material line into the injection cylinder 4 of the plasticizing unit 1 and injection unit 2.

[0109] This injection cylinder can be implemented for example like the embodiment variant represented by FIG. 1.

[0110] The plasticized material is supplied to the plasticizing unit 1 and the injection unit 2, wherein the plasticized material is led through an opening of an injection cylinder 4 to the plasticizing screw 13 formed as an injection screw.

[0111] The injection unit 2 of this embodiment has an injection cylinder 4 and a plasticizing screw 13 arranged in the injection cylinder 4. This plasticizing screw 13 is rotatable about its longitudinal axis and movable along the longitudinal axis axially in the injection direction.

[0112] These movements are initiated via a schematically represented drive unit 31. This drive unit 31 preferably comprises a rotary drive for the rotational movement and a linear drive for the axial injection movement.

[0113] The molding machine 3 is in signaling connection with a control or regulating unit 32. Control commands are output to the plasticizing unit 1 and the injection unit 2 by the control or regulating unit 32.

[0114] The control or regulating unit 32 can be connected to an operating unit or can be an integral constituent of such an operating unit.

[0115] A degassing device arranged on the injection cylinder 4 (which can be designed according to the embodiment of FIGS. 1 and 2) allows a plasticized material loaded with undesired gases (for example a recycled material) to be degassed such that it can be used for example in an injection-molding process known per se for producing molded parts, with the result that the undesired gases have no or at least a significantly reduced influence on the molded parts.

[0116] List of Reference Numbers: [0117] 1 plasticizing unit [0118] 2 injection unit [0119] 3 molding machine [0120] 4 injection cylinder [0121] 5 degassing opening [0122] 6 degassing device [0123] 7 flow element [0124] 8 filter device [0125] 9 flow loop [0126] 10 conveyor [0127] 11 compactor [0128] 12 cooling device [0129] 13 plasticizing screw [0130] 14 Venturi nozzle [0131] 15 cyclone separator [0132] 16 supply device [0133] 17 molten material line [0134] 18 heater bands [0135] 19 second plasticizing screw [0136] 20 second injection cylinder [0137] 21 supply opening [0138] 22 space in front of the screw [0139] 23 injection nozzle opening [0140] 24 mold [0141] 25 end plate [0142] 26 movable platen [0143] 27 fixed platen [0144] 28 clamping unit [0145] 29 machine frame [0146] 30 drive device [0147] 31 drive unit [0148] 32 control or regulating unit [0149] 33 nonreturn valve [0150] 34 continuous plasticizing unit