Device for extruding plastic compounds

• US 20020086077A1
• Filed: 01/23/2002
• Published: 07/04/2002
• Est. Priority Date: 08/05/1999
• Status: Abandoned Application

• Current Assignee: Hosokawa Bepex GmbH
• Original Assignee: Hosokawa Bepex GmbH
• Inventors: Stadler, Gerhard, Noller, Markus, Altvater, Frank
• Application Number:
  US10/055,049
• Publication Number:
  US 20020086077A1
• Time in Patent Office: Days
• US Class Current: 425/145
• CPC Class Codes: A21C 11/16 Extruding machines
• CPC Class Codes: B29C 2948/92019 Pressure
• CPC Class Codes: B29C 2948/92104 Flow or feed rate
• CPC Class Codes: B29C 2948/922 Viscosity; Melt flow index [MFI]; Molecular weight
• CPC Class Codes: B29C 2948/92209 Temperature
• CPC Class Codes: B29C 2948/9238 Feeding, melting, plasticising or pumping zones, e.g. the melt itself
• CPC Class Codes: B29C 2948/9258 Velocity
• CPC Class Codes: B29C 2948/9259 Angular velocity
• CPC Class Codes: B29C 2948/926 Flow or feed rate
• CPC Class Codes: B29C 2948/92723 Content, e.g. percentage of humidity, volatiles, contaminants or degassing
• CPC Class Codes: B29C 2948/92857 Extrusion unit
• CPC Class Codes: B29C 2948/92876 Feeding, melting, plasticising or pumping zones, e.g. the melt itself
• CPC Class Codes: B29C 2948/92904 Die; Nozzle zone
• CPC Class Codes: B29C 2948/92933 Conveying, transporting or storage of articles
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/2556 provided in or in the proximity of dies B29C48/302, B29C48/31, B29C48/325 take precedence
• CPC Class Codes: B29C 48/31 being adjustable , i.e. having adjustable exit sections
• CPC Class Codes: B29C 48/92 Measuring, controlling or regulating

Abstract

The device (10) has at least one feed instrument (12) for feeding a compound through a channel (24a; 24b; 24c) to a die (14). In order to prevent damage or destruction of the extruded compound during processing and to detect “overageing” of the compound, a sensing instrument (60a; 60b; 60c) is provided at the channel (24a; 24b; 24c) or at the die (14) in order to determine at least one measured variable (P_a; P_b; P_c) related to the viscosity of the compound. The feed instrument (12) and the die (14) are configured in such a way that the feed instrument (12) has a delivery pressure which oscillates over time at a frequency, and the die (14) has a flow resistance which oscillates at the same frequency.

Claims

1. Device (10) for extruding plastic compounds, having at least one feed instrument (12) for feeding a compound through a channel (24a;

24b;

24c) to a die (14), a sensing instrument (60a;

60b;

60c) being provided at the channel (24a;

24b;

24c) or at the die (14) in order to determine at least one measured variable (P_a;

P_b;

P_c) related to the viscosity of the compound, characterised in that

the feed instrument (12) and the die (14) are configured in such a way that the feed instrument (12) has a delivery pressure which oscillates over time at a frequency, and

the die (14) has a flow resistance which oscillates at the same frequency.

2. Device according to claim 1, characterised in that the measured variable is the pressure (p_a;

p_b;

p_c) of the compound.

3. Device according to claim 1 or 2, characterised in that the measured variable is the flow rate of the compound.

4. Device according to claim 1, 2 or 3, characterised in that

the sensing instrument (60a;

60b;

60c) is operatively coupled to a control instrument (62), and

the control instrument (62) is capable of controlling the feed instrument (12), as a function of at least one measured value determined by the sensing instrument (60a;

60b;

60c), in such a way that the exit velocity (v_s) of the compound from the die (14) fluctuates minimally.

5. Device according to claim 1, 2, 3 or 4, characterised in that

the device (10) comprises a transport instrument (16) for removing the compound extruded from the die (14),

the sensing instrument (60a;

60b;

60c) is operatively coupled to a/the control instrument (62), and

the control instrument (62) is capable of controlling the transport instrument (16), as a function of at least one measured value determined by the sensing instrument (60a;

60b;

60c), in such a way that the transport velocity (v_t) of the transport instrument (16) corresponds to the exit velocity (v_s) of the compound from the die (14).

6. Device according to claim 1, 2, 3, 4 or 5, characterised in that

the device (10) comprises a rotary instrument (26) having at least one rotatable die (14),

the sensing instrument (60a;

60b;

60c) is operatively coupled to a/the control instrument (62), and

the control instrument (62) is capable of controlling the rotary instrument (26), as a function of at least one measured value determined by the sensing instrument (60a;

60b;

60c), in such a way that the exit velocity (v_s) of the compound from the die (14) fluctuates minimally.

7. Device according to claim 1, 2, 3, 4, 5 or 6, characterised in that

a feed instrument (12) is connected through a plurality of channels (24a;

24b;

24c) to a die (14) having a plurality of outlet openings, and

a sensing instrument (60a;

60b;

60c) is in each case arranged at the channels (24a;

24b;

24c) or at the outlet openings of the die (14).

8. Device according to claim 7, characterised in that

the sensing instruments (60a;

60b;

60c) are operatively coupled to a/the control instrument (62), and

the control instrument (62) is capable of controlling the feed instrument (12), as a function of the measured values determined by the sensing instruments (60a;

60b;

60c), in such a way that the exit velocities of the individual compounds from the outlet openings of the die (14) fluctuate minimally relative to one another.