MXPA97002026A - Extruder with feedback tape control - Google Patents

Abstract

An extruder for excluding an associated material includes an extruder housing having a feed section, a center section including a throat section, and an outlet section with an extruder screw disposed in the extruder housing. The extruder also includes a throat in the throat section. The throat has a plurality of pins extending radially towards the housing. The pins are adjusted by a cam extending around the extruder housing. The cam has an internal wall having a plurality of cam surfaces engageable by pins. The radius of each of the cam surfaces gradually decreases from a maximum to a minimum radius distance. The pins have springs that urge the pins radially outward to make contact with the inner wall of the cam. The cam is rotated by a piston and cylinder assembly. The extruder also includes sensors for temperature, caliber, weight and other properties of the material. The extruder also has a control apparatus to control the speed of the extruder and the throat based on any combination of temperature, size, weight and production requirements while the extruder is running.

Description

EXTRUDER WITH FEEDBACK CONTROL OF ION FEEDBACK BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to the field of methods and apparatuses for extruding materials, such as rubber, and more specifically to methods and apparatuses for extruding materials at a temperature, gauge or substantially constant weight at variable rates of Extruder operation. 2. Description of the Related Art In the past, extruders have had adjustable settings to provide desired temperature during the operation of the extruder. These extruders and gargants, however, could not be adjusted dynamically while the heater was in operation. In addition, changes in extruder and blasting speed could affect extruder output, even though past extruders could not compensate for these changes without deducting the extruder production line to make throat and extruder velocity adjustments. The applicants recognized the need to make changes in extruder speed and throat position while the extruder was in operation, and to make these changes automatically and subject to variables such as material temperature, caliper, weight and other material properties. .

The present invention contemplates a new and improved extruder that is simple in design, effective in use, and overcomes the foregoing and other difficulties while providing better and more advantageous total results.

SUMMARY OF THE INVENTION In accordance with the present invention, a new and improved extruder is provided which maintains a sub-substantially constant temperature, caliper and weight in the extruded material under varying operating conditions. More particularly, in accordance with the present invention, the extruder for extruding an associated material includes an extruder housing having a feed section, a center section including a throat section, and an outlet section. The extruder also includes an e-truss screw disposed in the extruder housing having a core portion and a helical portion, the helical portion being helical about a longitudinal axis. The extruder further includes a throat that surrounds a portion of the throat section. The throat has a plurality of pins extending radially toward the housing about the longitudinal axis of the extruder screw. The pins are radially adjustable by a cam extending around the extruder housing. The cam has a center, an inner wall, and an external wall, the inner wall has a plurality of sections corresponding to the pins, each of the sections has a radial distance from the center of the cam the internal wall. The radial distance of each of the sections gradually decreases from a maximum radial distance to a minimum radial distance. The pins have springs that push the pins radially outward to make contact with the internal wall of the cam. The cam urges the pastures towards the throat section when the cam is rotated in a first direction so that the pins are in contact with the inner wall at a radial distance less than before the cam is rotated to reduce the cross sectional area of the throat section. The pins are radially movable outwardly from the throat section by the springs when the cam is rotated in one direction or so that the pins are in contact with the inner wall at a greater radial distance than before the cam is rotated. to increase the cross sectional area of the g section. The extruder also includes a rotating apparatus that rotates the cam. In accordance with one aspect of the invention, the method for extruding an associated material using an extruder incl. the steps of feeding the associated material into the feed section of the extruder housing and rotating the extruder ring to chew the associated material and to move the associated material through the extruder. The method further includes the steps of measuring the temperature of the associated material in the outlet section of the extruder housing using a temperature sensing apparatus and measuring gauge and weight of the associated material in the outlet section of the extruder housing using a measuring device. The method finally includes the step of adjusting the throat in response to changes in the associated extruded material to compensate for changes in temperature caliper and weight of the associated material in the outlet section of the extruder housing as determined by the apparatus for sensing temperature and the measuring device. An advantage of the present invention is that the extruder can measure the temperature of a raw material, such as a rubber, as it exits the extruder using a temperature sensor. Another advantage of the present invention is that the extruder can measure the caliber of the material, such as rubber, which is processed by the extruder using a measuring device such as a laser. Another advantage of the present invention is that the extruder can measure the weight of the material, such as rubber, which is cured by the extruder, using a measuring device such as a dumbbell. Another advantage of the present invention is that the extruder throat can be adjusted dynamically without stopping the extrusion.

Another advantage of the present invention is that the extruder control device controls the extruder and throat screw speed. Another advantage of the present invention is that the extruder control device controls the extruder and throat screw tightness while taking into consideration any combination of temperature, gauge, weight and material production requirements. Still other benefits and advantages of the invention will become apparent to those experienced in the field to which it pertains after a reading and understanding of the following detailed specification.

BRIEF DESCRIPTION OF THE DRAWINGS The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings that form a part of the present and where Figure 1 is a cross-sectional elevation, the schematic, of an extruder and auxiliary equipment that modalizes the invention; Figure 2 is a cross-sectional view of the extruder throat, taken along the line 2-2 of Figure 1; and, Figure 3 is a cross-sectional view of an extruder throat pin.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in which the -demonstrations are for purposes of illustrating a preferred embodiment of the invention only and not for purposes of limiting the same, Figure 1 shows a side view of an extruder 1 which it has an external housing 16 and a screw 22. Material such as rubber 24 is fed to the extruder 10 through a feed opening 28 in the rear part of the extruder 10. The rubber 24 is then chewed and processed by the screw 22 as the screw passes the rubber through the ex-trusher 10. The rubber 24 is then ejected from the extruder 10 and an outlet opening 34. In the preferred embodiment of the invention, the rubber 24 is applied to a roller 40 through a roller block 42 to form a product 46 which is carried on the rail on a conveyor belt 52. In case the production of the product 46 is to be arranged due to restrictions, such as decreased demand before the conveyor belt 52, the rotation speed of the screw 22 can be decreased. Some materials, however, will cool below an optical temperature as the screw 22 slows the chewing and extrusion process. This is particularly a problem for materials such as rubber. To maintain the temperature of the rubber 24 in the extruder 10, a groove 58 is used. The groove 58 is preferably positioned around the center of the extruder 10. The preferential screw 22 has a cylindrical region 64 where the throat is located. 58 to prevent damage to the fins 66 of the screw 22. The throat includes a number of pins 70 that can be arranged in the space within the housing 16 of the ex-trusher 10. The pins 70 offer resistance to the rubber 24 which is being forced through the screw 22 through the extruder 1 The increased resistance offered to the rubber 24 heats the rubber 24, allowing the extruder 10 to operate at a slower speed, however maintain a substantially constant temperature. Figure 2 shows a transverse section of the garget 58 and extruder 10 along the line 2-2 of Figure 1. The pins 70 are placed in circumferentially spaced positions around the screw 22. The pins 2 are driven in moving away from the screw 22 by elastic elements, such as springs 76. While the springs 76 are most preferred, the elastic elements may also include a hydraulic or pneumatic system, or a type of rotating mechanism. The pins 70 are surrounded by a cam 82 which holds the pins 70 in place. The cam 82 is generally circular in configuration, and has an internal wall 88 with cam surfaces 89. An external wall 90 of any appropriate configuration can be provided. The inner wall 88 has a number of cam surfaces 89 corresponding preferably to the number of pins 70. Each of the cam surfaces 89 of the inner wall 88 is inclined from a maximum radius 94 to a minimum radius 100. Because the pins 70 contact the cam surfaces 89 of the inner wall 88, the contact position along the inclination of the cam surfaces 89 of the inner wall 88 determines the position of the pins 70. For example, when the pins 70 contact the cam surfaces 89 of the inner wall 88 at the maximum radius 94, the pins move radially outwardly by the springs 76. When the cam 82 is rotated from In such a way that the pins 70 make contact with the cam surfaces 89 of the inner wall 88 in the radius 100 minimum, the pins 70 move towards the barrel 102 of the extruder 10. The distance of the pins 70 extend towards the barrel 102. of the extruder 10 determines the resistance offered to the rubber 24 as it moves through the extruder 10 through the fins 66 of the screw 22. The increased resistance increases the temperature of the rubber 24. If the rubber 24 has a At a temperature above the optimum temperature, the lever 82 is rotated so that the pins 70 make contact with the inner wall 88 in a position closer to or in the maximum range, thereby retracting the pins from the body. Extruder 10 and decreasing the amount of resistance offered to the rubber, which in turn reduces the rubber temperature. The modality of the extruder 10 shown in Figure 2 has 12 pins, and the internal wall 88 of the cam 82 has 12 cam surfaces 89. However, any suitable number of passages 70 and cam surfaces 89 may be employed. For example, it has been found that six pins 70 and six surfaces 89 d cam are satisfactory. Figure 3 shows a more detailed view of a pin together 103 for one of the pins 70. Each of the pins 70 is supported by one of the springs 76 which drives the pins radially outward in the direction d arrow A The springs 76 are preferably a plurality of bell ville springs. Each of the cam surfaces 89 of the inner wall 89 urges one of the pins 70 radially inward in the direction of the arrow B. As it rotates the cam 82, the cam surfaces 89 of the inner wall 8 they tilt, and thus change the position of the pins 70. If the cam 82 rotates so that the spokes of the cam surfaces 89 increase, the pins 70 move in the direction of the arrow A. If the cam 82 rotates so that the spokes of the cam surfaces 89 decrease, the pins 7 move in the direction of the arrow B. Each of the pins 70 may have a pin roll 136 at the point of contact with one of the pins. the cam surfaces 89 of the inner wall 88, which allows the cam 82 to rotate freely without damaging the chairs 70. With further reference to Figure 1, the cam 82 is preferably rotated by a piston assembly 106 and -cylinder, even when any method or method can be used Suitable for rotating the cam 82. The piston and cylinder assembly 106 preferably rotates the cam 82. The extruder 10 does not have to stop for rotation of the outer wall 90 of the throat 58. The temperature of the rubber 24 can be detected by a temperature sensor 112 placed in the outlet opening 34 of the extruder 10. In accordance with the extrusion properties of the material, a computer 118 can be programmed to provide the extruded material with the desired weight, size and other properties after extrusion. at a desired temperature. The temperature sensor 112 is connected to appropriate controls, such as the computer 118, which further controls the piston and cylinder assembly 106 and the speed at which the screw 22 rotates. When the computer 118 determines, based on the data of the temperature sensor 1 V 12, that the rubber 24 is at a temperature below the optimum level, the computer 118 activates the piston and cylinder co-member 106 to rotate the cam 82 so that the pins 70 move radially inward toward the extruder 10. The computer 118 The speed of rotation of the screw 22 of the extruder 10 can also be slowed. The chopper 118 can then increase the resistance of the throat 8 to maintain the optimum temperature in the rubber 24. The computer 118 is preferably connected to an apparatus 124 of gauge measurement and a measuring device, such as a weighing scale 126. The preferred gauge measuring apparatus 124 includes a laser for making fine measurements of the gauge, or size, of the product 46 as it exits from the extruder 10 on the conveyor belt 52. The weight balance 12 makes fine measurements of the weight of the product 46. The position of the throat 58 can affect the output of the extruder 10, requiring an appropriate adjustment in the rotation regime of the screw 22 to maintain the specified caliber and weight of the product. finished product 46 The computer 118 can also be used to interpret all data related to the temperature, temperature, weight and other properties of the rubber 24 and product 46. The computer 118 controls the rate of rotation of the screw 22 the position of the throat 58. The computer 118 is preferred because of the relationships between temperature, caliper, weight and other properties of rubber 24 and finished product 46, the position d throat 58 and the rotation rate of screw 22 are non-linear. It is understood that another type of throat for controlling and passing the rubber 24 through the extruder 10 can be used. Preferred embodiments have been described as appropriate. It will be apparent to those skilled in the art that the above apparatus and methods may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all these modifications and alterations as long as they fall within the scope of the appended claims or the equivalents thereof.

Claims (10)

CLAIMS:

1. - An extruder for extruding an associated material, comprising: an extruder housing having a section of storage, a central section including a throat section, and an outlet section; an extruder screw rotatably mounted in the extruder housing, the extruder screw having a core portion and a helical portion with the helical portion being helical about a longitudinal axis, characterized by: a throat surrounding a portion of the section At the throat, the throat having a plurality of pins extending radially toward the housing around the longitudinal axis of the extruder screw, the pins being radially adjustable by a circular cam extending around the extruder housing, cam having a center, an inner wall, and an outer wall, the inner wall having a plurality of cam surfaces for coupling by the pins, each of the cam surfaces having a radius from the center, the radius gradually decreasing from a ra gave maximum to a minimum radius, the pins having elastic elements to drive the past s radially outward to make contact with the cam surfaces, the cam surfaces driving the pins radially inward toward the throat section when the cam is rotated in a first direction so that the pins are in contact with the fingers. cam surfaces at a radius less than before the cam is rotated to reduce the cross-sectional area of the throat section, and the pins being movable radially outwardly from the throat section by the elastic elements when the cam is rotated in an opposite direction so that the pins are in contact with the cam surfaces at a greater radius than before the cam was rotated to increase the cross-sectional area of the throat section; and, a cam rotation element for rotating the cam.

2. The extruder of claim 1, further characterized by the cam rotation element comprising a joint of cylinder and cylinder, the piston and cylinder assembly connected to the cam to rotate the cam in the first direction. and in the opposite direction.

3. The extruder of claim 2, further characterized by temperature sensing elements for sensing the temperature of the associated material in the outlet section of the extruder housing and the cam rotation element being sensitive to a change in temperature determined by the element of temperature perception.

4. - The extruder of claim 3, further characterized by control elements for controlling the extruder and the throat, the control element being connected to the piston and cylinder assembly and the temperature sensing element, and the control element activating the assembly of piston and cylinder to move the throat in response to a change in temperature as it is perceived by the temperature sensing element.

5. The extruder of claim 4, further characterized by measuring elements for measuring the gauge of the associated material extruded from the outlet section of the extruder housing, the measured measuring element connected to the control element, the control by activating the throat in response ab abies in the caliber of the associated material as detected by the measuring element.

6. The extruder of claim 4, further characterized by weight elements for measuring the weight of the associated extruded material from the outlet section of the extruder housing, the weight element being connected to the control element, the element Control by activating the throat in response to changes in the weight of the associated material as detected by the weight element.

7. The extruder of claim 4, further characterized by a control element that is connected to the element for rotating the extruder screw, thereby controlling the speed at which the extruder screw rotates.

8. - The extruder of claim 2, further characterized by the piston and cylinder assembly that is operable to rotate the cam during the operation of the extruder.

9. A method for extruding a material associated with an extruder having an extruder housing with a feed section, a center section having a gauge section, and an outlet section, an extruder screw, element of temperature perception to measure the temperature in the outlet section, measuring elements to measure the caliper and pe and other properties in the outlet section, a throat to change the cross-sectional area of the throat section and elements of control to control the extruder, the method characterized by the steps of: feeding the associated material into the feed section of the extruder housing; rotating the extruder screw to chew the associated material and to move the associated material through the trusor; measuring the temperature of the associated material in the exit section of the extruder housing using a temperature sensing element; measure the caliper and weight of the associated material in the exit section of the extruder housing using the measuring element; and, adjusting the throat in response to changes in the associated extruded material to compensate for changes in temperature, caliper and weight of the associated material in the extruder housing exit section as determined by the temperature sensing element and the measuring element.

10. The method of claim 9, wherein the gage comprises a plurality of pins, a cam having camming surfaces, elastic elements urging the pastures into contact with the camming surfaces, and a piston assembly and cylinder connected to the cam, the method further characterized by the steps of: rotating the cam using the piston and cylinder assembly; and, in this manner, move the pins radially in the gargle section to change the chewing and control the temperature of the associated material in the extruder housing.