Device and method for continuously extruding tubing having different materials

Abstract

A method of co-extruding material. The method includes controlling the flow of a first extruded material to an infeed of a die by a first plunger positioned in a first material delivery channel; moving the first plunger between a first plunger first position and a first plunger second position, the first plunger creating a vacuum or area of low pressure as the first plunger is moved from the first plunger first position to the first plunger second position; controlling the flow of a second extruded material to the infeed of the die by a second plunger positioned in a second material delivery channel; moving the second plunger between a second plunger first position and a second plunger second position, the second plunger creating a vacuum or area of low pressure as the second plunger is moved from the second plunger first position to the second plunger second position.

1 . A method of co-extruding material, the method comprising:
 providing first extruded material through a first material delivery channel to a die;   providing second extruded material through a second material delivery channel to a die;   controlling the flow of the first extruded material through the first material delivery channel by a first plunger positioned in the first material delivery channel; and   controlling the flow of the second extruded material through the second material delivery channel by a second plunger positioned in the second material delivery channel.   
     
     
         2 . The method of  claim 1 , further comprising:
 moving the first plunger from a first plunger first position in which to the first plunger is extended in the first material delivery channel toward the die, and a first plunger second position in which the first plunger is retracted in the first material delivery channel away from the die;   wherein as the first plunger is moved to the extended position, the first extruded material is forced from the portion of the first material delivery channel to the die, and wherein as the first plunger is moved to the retracted position, the flow of the first extruded material from the portion of the first material delivery channel to the die is slowed or stopped.   
     
     
         3 . The method of  claim 2 , further comprising;
 moving the second plunger being from a second plunger first position in which to the second plunger is extended in the second material delivery channel toward the die, and a second plunger second position in which the second plunger is retracted in the second material delivery channel away from the die;   wherein as the second plunger is moved to the extended position, the second extruded material is forced from the portion of the second material delivery channel to the die, and wherein as the second plunger is moved to the retracted position, the flow of the second extruded material from the portion of the second material delivery channel to the die is slowed or stopped.   
     
     
         4 . The method of  claim 1 , further comprising:
 positioning the first plunger in a portion of the first material delivery channel positioned proximate the die.   
     
     
         5 . The method of  claim 4 , further comprising:
 positioning the second plunger in a portion of the second material delivery channel positioned proximate the die.   
     
     
         6 . The method of  claim 1 , further comprising:
 providing third extruded material through a third material delivery channel to the die;   wherein the die has an outer layer and an inner layer, the first material delivery channel and the second material delivery channel cooperating with the outer layer of the die and the third material delivery channel cooperating with the inner layer of the die.   
     
     
         7 . A method of co-extruding material through a die, the method comprising:
 providing first extruded material through a first material delivery channel to an infeed of the die;   providing second extruded material through a second material delivery channel to the infeed of the die;   controlling the flow of the first extruded material through the first material delivery channel by a first plunger positioned in the first material delivery channel;   moving the first plunger between a first plunger first position and a first plunger second position, the first plunger creating a vacuum or area of low pressure as the first plunger is moved from the first plunger first position to the first plunger second position;   controlling the flow of the second extruded material through the second material delivery channel by a second plunger positioned in the second material delivery channel; and   moving the second plunger between a second plunger first position and a second plunger second position, the second plunger creating a vacuum or area of low pressure as the second plunger is moved from the second plunger first position to the second plunger second position.   
     
     
         8 . The method of  claim 7 , further comprising:
 providing third extruded material through a third material delivery channel to the infeed of the die;   wherein the die has an outer layer and an inner layer, the first material delivery channel and the second material delivery channel cooperating with the outer layer of the die and the third material delivery channel cooperating with the inner layer of the die.   
     
     
         9 . The method of  claim 7 , wherein a controller controls the movement of the first plunger between the first plunger first position and the first plunger second position, the controller controls the movement of the second plunger between the second plunger first position and the second plunger second position. 
     
     
         10 . The method of  claim 7 , wherein a position controlled actuator with an activation member is attached to each of the first and second plungers. 
     
     
         11 . The method of  claim 10 , wherein the position controlled actuators are electro-mechanical valves driven by servo motors. 
     
     
         12 . The method of  claim 7 , wherein as the first plunger is moved to the first plunger first position, the first material is forced from the first material delivery channel to the infeed of the die, and wherein as the first plunger is moved to the first plunger second position, the flow of the first material from the first material delivery channel to the infeed of the die is slowed or stopped. 
     
     
         13 . The method of  claim 12 , wherein as the second plunger is moved to the second plunger first position, the second material is forced from the second material delivery channel to the infeed of the die, and wherein as the second plunger is moved to the second plunger second position, the flow of the second material from the second material delivery channel to the infeed of the die is slowed or stopped. 
     
     
         14 . The method of  claim 7 , wherein:
 in the first plunger first position the first plunger is extended in the first material delivery channel toward the infeed of the die, and in the first plunger second position the first plunger is retracted in the first material delivery channel away from the infeed of the die; and   in the second plunger first position the second plunger is extended in the second material delivery channel toward the infeed of die, and in the second plunger second position the second plunger is retracted in the second material delivery channel away from the infeed of the die.   
     
     
         15 . A method of co-extruding material, the method comprising:
 providing first extruded material through a first material delivery channel to an infeed of a die;   providing second extruded material through a second material delivery channel to the infeed of the die;   controlling the flow of the first extruded material through the first material delivery channel by a first plunger positioned in the first material delivery channel;   moving the first plunger between a first plunger first position in which the first plunger is extended in a first lower portion of the first material delivery channel toward the infeed of the die and a first plunger second position in which the first plunger is retracted in the first lower portion of the first material delivery channel away from the infeed of the die, the first plunger creating a vacuum or area of low pressure as the first plunger is moved from the first plunger first position to the first plunger second position;   controlling the flow of the second extruded material through the second material delivery channel by a second plunger positioned in the second material delivery channel;   moving the second plunger between a second plunger first position in which the second plunger is extended in a second lower portion of the second material delivery channel toward the infeed of the die and a second plunger second position in which the second plunger is retracted in the second lower portion of the second material delivery channel away from the infeed of the die, the second plunger creating a vacuum or area of low pressure as the second plunger is moved from the second plunger first position to the second plunger second position.   
     
     
         16 . The method of  claim 15 , further comprising:
 providing third extruded material through a third material delivery channel to the infeed of the die;   wherein the die has an outer layer and an inner layer, the first material delivery channel and the second material delivery channel cooperating with the outer layer of the die and the third material delivery channel cooperating with the inner layer of the die.   
     
     
         17 . The method of  claim 15 , wherein a controller controls the movement of the first plunger between the first plunger first position and the first plunger second position, the controller controls the movement of the second plunger between the second plunger first position and the second plunger second position. 
     
     
         18 . The method of  claim 15 , wherein a position controlled actuator with an activation member is attached to each of the first and second plungers. 
     
     
         19 . The method of  claim 15 , wherein as the first plunger is moved to the first plunger first position, the first material is forced from the first lower portion of the first material delivery channel to the infeed of the die, and wherein as the first plunger is moved to the first plunger second position, the flow of the first material from the first lower portion of the first material delivery channel to the infeed of the die is slowed or stopped. 
     
     
         20 . The method of  claim 19 , wherein as the second plunger is moved to the second plunger first position, the second material is forced from the second lower portion of the second material delivery channel to the infeed of the die, and wherein as the second plunger is moved to the second plunger second position, the flow of the second material from the second lower portion of the second material delivery channel to the infeed of the die is slowed or stopped.