Extrusion line control system
AssigneeNucleonics Data Systems
InventorsMichael C. Bertin, Richard L. Hicksted, James M. Mitsuhashi
Life of this patent
Estimating the term…
Abstract
An extrusion line for producing rubber tire tread. Method and apparatus for continuously controlling extrusion line operation to maintain a predetermined length and weight for the finished product. Sensors for unit weight, extruder speed and swell, extruder load, extrudate temperature at the extruder and at the skiver, and conveyor speeds, signal conditioning circuits, and controls for take away conveyor speed, extruder speed, unit weight and skiver length.
Claims40
In a rubber extrusion line having an extruder, a take away conveyor, a unit weight scale, and a skiver, with the extrudate moving in a continuous strip from said extruder onto said take away conveyor, past said unit weight scale to said skiver, the improvement comprising in combination:
- drive means coupled to said take away conveyor for controlling the speed of said take away conveyor in response to a drive signal;
- a first sensor connected to said unit weight scale for producing a first signal varying as a function of the weight measured at said unit weight scale;
- a second sensor positioned adjacent the outlet of said extruder for producing a second signal varying as a function of extrudate speed and swell at the outlet of said extruder;
- a first low pass filter with means for connecting said first signal as an input for substantially removing short term components of said first signal;
- a second high pass filter with means for connecting said second signal as an input for substantially removing long term components of said second signal, where a long term component varies with a period of about 10 to about 60 minutes and a short term component varies with a period of about 2 to about 60 seconds;
- and
- a control unit with means for connecting the outputs of said first and second filters as inputs for combining the inputs producing a drive signal for said drive means.
In a rubber extrusion line having an extruder, a take away conveyor, a unit weight scale, and a skiver, with the extrudate moving in a continuous strip from said extruder onto said take away conveyor, past said unit weight scale to said skiver, the improvement comprising in combination:
- a first sensor coupled to said extruder for producing a first signal varying as a function of the load of said extruder;
- a second sensor positioned adjacent the outlet of said extruder for producing a second signal varying as a function of extrudate speed and swell at the outlet of said extruder;
- extruder speed control means coupled to said extruder for controlling the speed of said extruder in response to a speed signal;
- high pass filter means with means for connecting said first and second signals as input for substantially removing long term components of said first and second signals, where a long term component varies with a period of about 10 to about 60 minutes and a short term component varies with a period of about 2 to about 60 seconds;
- and
- a speed unit with means for connecting the output of said high pass filter means as input for providing a speed signal for said speed control means.
A method of controlling a rubber extrusion line having an extruder, a take away conveyor, a unit weight scale, and a skiver, with the extrudate moving in a continuous strip from the extruder onto the take away conveyor, past the unit weight scale to the skiver, including the steps of:
- sensing the weight measured at the unit weight scale and producing a first signal varying as a function of the weight;
- sensing the extrudate speed and swell at the output of the extruder and producing a second signal varying as a function of the speed and swell;
- filtering the first signal substantially removing short term components thereof;
- filtering the second signal substantially removing long term components thereof, where a long term component varies with a period of about 10 to about 60 minutes and a short term component varies with a period of about 2 to about 60 seconds;
- and
- varying the speed of the take away conveyor as a function of the combination of the filtered first and second signals.
A method of controlling a rubber extrusion line having an extruder, a take away conveyor, a unit weight scale, and a skiver, with the extrudate moving in a continuous strip from the extruder onto the take away conveyor, past the unit weight scale to the skiver, including the steps of:
- sensing the extrudate speed and swell at the output of the extruder and producing a first signal varying as a function of the speed and swell;
- sensing the load of the extruder and producing a second signal varying as a function of the load;
- filtering the first and second signals substantially removing long term components thereof where a long term component varies with a period of about 10 to about 60 minutes and a short term component varies with a period of about 2 to about 60 seconds;
- and
- varying the speed of the extruder as a function of the combination of the filtered first and second signals.
Dependencies are inferred from the claim text.