Kneading/extruding equipment with feedforward control of latter stage pump

Patent metadata

Field	Value
Publication number	US-9333674-B2
Application number	US-201313759448-A
Country	US
Kind code	B2
Filing date	Feb 5, 2013
Priority date	Mar 5, 2012
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

The present invention provides kneading/extruding equipment capable of stable operation by keeping the pressure of kneaded material before a first-stage gear pump in steady operation (molding) and preventing fluctuation of the pressure of kneaded material before the first-stage gear pump constant from largely affecting the pressure of kneaded material before a latter-stage gear pump at start-up or upon change of production rate, and thus capable of responding to an increase in production rate while securing a high-quality molded product, and an operation control method thereof. The kneading/extruding equipment comprises: a rotational speed feedback control unit for a first gear pump, which feedback-controls the rotational speed of the first gear pump, and a rotational speed feedforward control unit for a second gear pump, which feedforward-controls the rotational speed of the second gear pump.

First claim

What is claimed is:

1. Kneading/extruding equipment, comprising:
a raw material feeder;
an extruding machine which kneads and extrudes raw material supplied from the raw material feeder;
a first-stage gear pump for pressure-raising the kneaded material, which is provided on the downstream side of the extruding machine;
a pressure loss generation device through which the kneaded material discharged from the first-stage gear pump is passed and which causes a pressure loss in the kneaded material during the passing;
a latter-stage gear pump for pressure-raising the kneaded material discharged from the pressure loss generation device;
a first-stage variable-speed motor for driving the first-stage gear pump;
a latter-stage variable-speed motor for driving the latter-stage gear pump;
a first-stage pressure sensor for detecting a pressure of kneaded material on the inlet side of the first-stage gear pump; and
a control device which controls the rotational speed of the first-stage gear pump through the first-stage variable-speed motor and controls the rotational speed of the latter-stage gear pump through the latter-stage variable-speed motor, wherein
the control device comprises:
a rotational speed feedback control unit for the first-stage gear pump, which feedback control unit controls the rotational speed of the first-stage gear pump so that a pressure value output from the first-stage pressure sensor is conformed to a predetermined first-stage pressure set value; and
a rotational speed feedforward control unit for the latter-stage gear pump, which feedforward control unit controls the rotational speed of the latter-stage gear pump based on a signal from the rotational speed feedback control unit for the first-stage gear pump.

2. The kneading/extruding equipment according to claim 1 , wherein the equipment further comprises a latter-stage pressure sensor for detecting a pressure of kneaded material on the inlet side of the latter-stage gear pump,
the control device further comprises a rotational speed feedback control unit for the latter-stage gear pump, which feedback-controls the rotational speed of the latter-stage gear pump so that a pressure value output from the latter-stage pressure sensor is conformed to a predetermined latter-stage pressure set value, and
the rotational speed of the latter-stage gear pump is controlled by combining an output of the rotational speed feedforward control unit for the latter-stage gear pump with an output of the rotational speed feedback control unit for the latter-stage gear pump.

3. The kneading/extruding equipment according to claim 1 or 2 , wherein the rotational speed feedforward control unit for the latter-stage gear pump performs the control by use of a manipulation amount signal generated by the rotational speed feedback control unit for the first-stage gear pump.

4. The kneading/extruding equipment according to claim 1 or 2 , wherein the rotational speed feedforward control unit for the latter-stage gear pump performs the control by use of a pressure value output from the first-stage pressure sensor.

5. The kneading/extruding equipment according to claim 1 , wherein a PID control based on a deviation between the pressure value output from the first-stage pressure sensor and the predetermined first-stage pressure set value is performed in the rotational speed feedback control unit for the first-stage gear pump.

6. The kneading/extruding equipment according to claim 2 , wherein a PID control based on a deviation between a pressure value output from the latter-stage pressure sensor and the predetermined latter-stage set value is performed in the rotational speed feedback control unit for the latter-stage gear pump.

7. The kneading/extruding equipment according to claim 2 , wherein the equipment further comprises a third-stage gear pump provided on the downstream side of the latter stage across from a further pressure loss generation device, and the control device further comprises a rotational speed feedforward control unit for the third-stage gear pump, which controls the rotational speed of the third-stage gear pump based on a signal from the rotational speed feedback control unit for the latter-stage gear pump.

8. An operation control method of kneading/extruding equipment comprising:
providing a raw material feeder; an extruding machine which kneads and extrudes raw material supplied from the raw material feeder; a first-stage gear pump for pressure-raising kneaded material, which is provided on the downstream side of the extruding machine; a pressure loss generation device through which the kneaded material discharged from the first-stage gear pump passes and which causes a pressure loss in the kneaded material during the passing; a latter-stage gear pump for pressure-raising the kneaded material discharged from the pressure loss generation device; a first-stage variable-speed motor for driving the first-stage gear pump; a latter-stage variable-speed motor for driving the latter-stage gear pump; a first-stage pressure sensor for detecting a pressure of kneaded material on the inlet side of the first-stage gear pump; and a control device which controls the rotational speed of the first-stage gear pump through the first-stage variable-speed motor and controls the rotational speed of the latter-stage gear pump through the latter-stage variable-speed motor;
a step in which the control device feedback-controls the rotational speed of the first-stage gear pump so that a pressure value output from the first-stage pressure sensor is conformed to a predetermined first-stage pressure set value; and
a step in which the control device feedforward-controls the rotational speed of the latter-stage gear pump based on a signal related to the step of feedback controlling the rotational speed of the first-stage gear pump.

9. The operation control method of kneading/extruding equipment according to claim 8 , wherein
the kneading/extruding equipment further comprises a latter-stage pressure sensor for detecting a pressure of kneaded material on the inlet side of the latter-stage gear pump, and the operation method further comprises steps of:
feedback-controlling the rotational speed of the latter-stage gear pump so that a pressure value output from the latter-stage pressure sensor is conformed to a predetermined latter-stage pressure set value; and
controlling the rotational speed of the latter-stage gear pump by combining an output in the rotational speed feedforward control step for the latter-stage gear pump and an output of the rotational speed feedback control step for the latter-stage gear pump.

10. The operation control method of kneading/extruding equipment according to claim 8 or 9 , wherein
in the step of feedforward-controlling the rotational speed of the latter-stage gear pump, the control is performed by use of a manipulation amount signal generated in the rotational speed feedback control step for the first-stage gear pump.

11. The operation control method of kneading/extruding equipment according to claim 8 or 9 , wherein
in the step of feedforward-controlling the rotational speed of the latter-stage gear pump, the control is performed by use of a pressure value output from the first-stage pressure sensor.

12. The operation control method of kneading/extruding equipment according to claim 8 , wherein
in the step of feedback-controlling the rotational speed of the first-stage gear pump, a PID control based on a deviation between a pressure value output from the first-stage pressure sensor and the predetermined pressure set value is performed.

13. The operation control method of kneading/extr

Assignees

• Kobe Steel Ltd
• Kobe Steel Ltd

Inventors

• Asagiri Shinichi
• Abe Satoshi
• Iwasaki Shin
• Kuroda Yoshinori
• Iritani Kazuo
• Minami Kayoko

Classifications

• B29C48/39

  a first extruder feeding the melt into an intermediate location of a second extruder · CPC title

• B29C48/92

  Measuring, controlling or regulating · CPC title

• B29C48/387

  using a screw extruder and a gear pump · CPC title

• B29B7/728

  Measuring data of the driving system, e.g. torque, speed, power, vibration (B29B7/724 takes precedence) · CPC title

• B29C48/693

  Substantially flat filters mounted at the end of an extruder screw perpendicular to the feed axis · CPC title