Patent RU-2239557-C1 (RU)
Title: System of automatic control of melt temperature and protection of electric motor of an extruder against overheating
Inventor: KIZHAEV S A
IPC: B29C48/92
Filed: 2003-07-28
Granted: 2004-11-10
Abstract: FIELD: control over extrusion of biopolymers and application of polymeric shells on cables and wires billets. 
     SUBSTANCE: the invention is dealt with the field of automatic control and may be used to control over extrusion of biopolymers and application of polymeric shells on cables and wires billets. The system contains three channels of control over an extruder. The first channel is intended for a heating of low-temperature polymer and includes in series connected a corrector of control signals, a local regulator, an actuating mechanism to control a line of delivery of a heating agent and outlet of which exit is the first inlet of the extruder. The second channel is intended for delivery of a processed polymer and contains an actuating mechanism, outlet of which is the second inlet of the extruder, and sensors of consumption of the raw material and its moisture, inputs of which are connected to the second inlet of the extruder. The third channel is intended for the raw materials processing and its extrusion through a head of the extruder. The channel contains in series connected: an algebraic block, the input of which is connected to the outputs of the sensors of the raw material consumption and its moisture; a local regulator; an actuating mechanism; an adjustable drive, output of which is the third input of the extruder. The system also contains a detector of temperature of the extrudate melt connected by its input to the first outlet of the head of the extruder and by its output connected with the second input of the local regulator of the first control channel; the pressure gage connected by its input to the second outlet of the head of the extruder and with its output linked to the second input of the local regulator in the third channel; a gage of moisture of an extrudate connected the third output of the head of the extruder and with its output connected to the input of the control signals corrector, the second output of which is fused to the third input of the local regulator of the third channel. The system includes in series connected: a unit of setting of specific heat of the processed materials containing in series connected a gauge of voltage of the polymer heating, a block of product, a summation unit and a divider, a gauge of the material heating current connected by its output to the second input of the block of the product, in series connected a gauge of current of the electric motor of the extruder drive and a functional transducer of a current of the electric motor, the second input of which is an input of a set point of a current of the electric motor, and its output, on which forms a signal proportional to a difference of a current of the electric motor and a current of the set point, is connected to the second input of the summation unit. There is also a gauge to measure a temperature of the melt, an output of which is connected with the second input of the block of the divider; in series connected a source of stabilized voltage and a potentiometer, output of which is the output of the unit of setting a specific heat of a material; the toggle actuator with its normally closed contact fused to an output of a potentiometer, and with its normally open contact connected to an output of the unit of divider. The output of the toggle actuator is connected through a graduated resistor to the device of indication. The first input of the summation unit is connected to the third input of a local regulator of the first channel, the second input of the summation unit is fused to the second output of the adjustable drive of the extruder and to the fourth input of the local regulator of the first channel. The third input of the summation unit is connected to the output of the gauge of the temperature transmitter of the melt of the extrudate in the first channel. The unit of an electrical heating of the extruder is intended for heating of high-temperature polymer and is connected the fourth input of the extruder. The invention ensures an increase of productivity, reliability of system and quality of processing of polymers as well as expansion of functionalities of the system. 
     EFFECT: the invention ensures increased productivity, reliability of system and quality of processing of polymers, expansion of functionalities of the system. 4 dwg