CN102366999A

CN102366999A - High precision automatic control device for weight per unit length of material discharged from extruder

Info

Publication number: CN102366999A
Application number: CN2011103358560A
Authority: CN
Inventors: 王根乐
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-08-26
Filing date: 2011-10-31
Publication date: 2012-03-07
Anticipated expiration: 2031-10-31
Also published as: CN102275292A; CN102366999B

Abstract

The invention relates to a high precision automatic control device for the weight per unit length of a material discharged from an extruder. The device is characterized in that: the input terminus of a controller is connected with a weighing apparatus, and the output terminal of the controller is connected with a driving motor of an extruding screw of the extruder or a driving motor of traction rolls; the weighing apparatus comprises a raw material hopper, a frame and a weighing hopper, the raw material hopper is arranged on the upper end of the frame, and the lower outlet of the raw material hopper is provided with a gate; the weighing hopper is arranged under the raw material hopper, one side of the weighing hopper is connected with one end of a lever, the other end of the lever is provided with a fixed counterweight, the fulcrum of the lever is hinged to the frame, a lower proximity switch is arranged under the fixed counterweight; a movable counterweight is arranged above the fixed counterweight, the movable counterweight is movably supported on a counterweight support, and an upper proximity switch is arranged under the movable counterweight; and the gate, the upper proximity switch and the lower proximity switch are respectively connected with the controller. The device of the invention has the advantages of structure simplification, cost reduction, simple control principle and control precision improvement.

Description

The high precision in control device of extruder discharging unit weight

Technical field

The present invention relates to a kind of high precision in control device of extruder discharging unit weight, be mainly used on inflation film manufacturing machine, drawbench, electric wire machine, plastics wrapping machine and spray silk (bar) machine the length of discharging, the uniformity of thickness are controlled.

Background technology

A kind of basic skills of the evenness of discharge property control to extruder is in the prior art; Adopt balance-type type meausring apparatus meter to calculate charging rate (being the material quantity that gets in the unit interval in the extruder); Then according to the extruding screw of charging rate control extruder or the rotating speed of carry-over pinch rolls; The rotating speed of charging rate and described extruding screw is inversely proportional to, or is directly proportional, keep film thickness even with the rotating speed of carry-over pinch rolls.The meausring apparatus of this balance-type type mainly comprises former hopper, frame, scale hooper and charging adapter (being connected with the charging aperture of extruder), and the top and bottom that are installed in frame are respectively taken in former hopper and charging, in the outlet of the lower end of this former hopper gate is housed; Described scale hooper is installed between former hopper and the charging adapter; One side of this scale hooper is connected with an end of a lever; The other end of this lever is equipped with a fixed weight, and the fulcrum of this lever is hinged on this frame, and position-limit mechanism and feed supplement are near switch about on this lever, being provided with; Material level is housed near switch in the outlet of the lower end of scale hooper.In the time interval that this meausring apparatus utilizes material level to send twice adjacent feed signal near switch, divided by this time interval, and then calculate extruder discharging unit weight with the weight of charging one scale hooper.But because the measure error of material level is bigger, the inlet amount precision in the unit interval that therefore calculates is lower.In order to address the above problem, adopt two cover balance units to carry out weighing in addition, though improve control accuracy to a certain extent, the structural complexity that has increased has improved cost and fault rate.

In addition; At every turn in scale hooper during blowing, because closing gate needs a process, particulate material has resistance at random to gate; All can cause putting into the raw material of scale hooper and there is error in the weight of setting at every turn; If to carry out timing and calculating this moment, must cause controlling the result and bigger error occur, influence control accuracy.

Summary of the invention

The object of the invention just provides a kind of high precision in control device of extruder discharging unit weight, and to solve the complex structure that prior art exists, cost is high, is difficult for maintenance and debugging, and control accuracy is poor, and cost improves and the high problem of fault rate.

Technical scheme of the present invention is: a kind of high precision in control device of extruder discharging unit weight; Comprise controller and meausring apparatus; The input of this controller is connected with meausring apparatus; The output of this controller is connected with the drive motors of the extruding screw of extruder or the drive motors of carry-over pinch rolls, and described meausring apparatus comprises former hopper, frame, scale hooper and charging adapter, and the top and bottom that are installed in frame are respectively taken in former hopper and charging; In the outlet of the lower end of this former hopper gate is housed, this gate is connected with a gate driving device; Described scale hooper is installed between former hopper and the charging adapter; One side of this scale hooper is connected with an end of a lever; The other end of this lever is equipped with a fixed weight, and the fulcrum of this lever is hinged on this frame, on this lever, is provided with position-limit mechanism up and down; Below this fixed weight, be equipped with down near switch; It is characterized in that: above described fixed weight, be provided with moving counterweight, this moving counterweight is supported on the counterweight support versatilely, below this moving counterweight, is provided with near switch; The controlled end of this gate driving device, go up near switch be connected with described controller respectively near switch down.

Described moving counterweight is made up of main body and the undergauge slide bar that is located at this main body lower end; This undergauge slide bar is supported on the described counterweight support with longitudinal sliding; All be in when the next at this fixed weight and moving counterweight, leave the working clearance between the undergauge slide bar lower end of the top and moving counterweight of this fixed weight; The lower end central authorities of this undergauge slide bar are sphere or tip.

Be provided with vertical hole at described counterweight support, vertically linear bearing is equipped with in the hole in this, in the centre bore of this linear bearing, inserts the undergauge slide bar of described moving counterweight lower end with being slidingly matched.

Described moving counterweight is discoid, and described undergauge slide bar is cylindrical, and coaxial with this moving counterweight.

Described moving counterweight is made up of main body and swing arm, and an end and the described frame of this swing arm are hinged, and the other end is connected with this main body; Upper end in described fixed weight is provided with push rod, on the top of this push rod roller is housed; All be in when the next at this fixed weight and moving counterweight, leave the working clearance between the top of the roller on this push rod and moving counterweight following.

In the main body of described moving counterweight or swing arm, be provided with adjustable counterweight.

Described gate driving device adopts fluid cylinder, cylinder or electric device; Described controller adopts microcomputer or Programmable Logic Controller.

On described carry-over pinch rolls, speed probe is housed, and is connected with described controller.

The output of described controller is connected with the drive motors of described carry-over pinch rolls through frequency converter, has saved speed probe.

Be provided with and surface-mounted support in the bottom of described frame; The charging aperture that lower end outlet and extruder are taken in described charging is oppositely arranged but leaves the gap, or the lower end outlet is taken in described charging is connected with the charging aperture of extruder through flexible pipe.

Advantage of the present invention is: it is time zero that the collection activity counterweight drops to a certain desired location moment corresponding with fixed weight; Raw material weight in the corresponding this moment scale hooper is certain; Ignored the error that blowing initial time raw material weight exists, improved control accuracy greatly, and simplified the structure; Manufacturing cost and fault rate have been reduced, easily maintenance and debugging.

Description of drawings

Fig. 1 be the present invention's general structure of being applied in first embodiment on the extruder (no raw material or have only small number of materials in the scale hooper, scale hooper is in upper; Adopt speed probe to measure the rotating speed of carry-over pinch rolls) sketch map;

Fig. 2 is one of fundamental diagram of first embodiment of the invention (scale hooper just filled raw material after, be in the next);

Fig. 3 is two (the scale hooper position that picks up counting is the starting point moment this moment) of the fundamental diagram of first embodiment of the invention;

Fig. 4 is three (moving counterweight is fallen on the counterweight support, and with fixed weight state of contact) of the fundamental diagram of first embodiment of the invention;

Fig. 5 is general structure (identical with the state of Fig. 1, as the to save speed probe) sketch map that the present invention is applied in second embodiment on the extruder;

Fig. 6 is general structure (swing arm moving counterweight) sketch map that the present invention is applied in the 3rd embodiment on the extruder;

Fig. 7 is general structure (meausring apparatus and the extruder isolating construction) sketch map that the present invention is applied in the 4th embodiment on the extruder.

The specific embodiment

Referring to Fig. 1-Fig. 4; First embodiment of the High Accuracy Control device of a kind of automatic control extruder discharging unit weight of the present invention; This embodiment comprises controller 18 and meausring apparatus; The input of this controller 18 is connected with meausring apparatus, and the output of this controller 18 is connected with the drive motors 14 of the extruding screw of extruder 15 or the drive motors of carry-over pinch rolls 16.

The meausring apparatus of this embodiment comprises that former hopper 1, frame 2, scale hooper 7 and charging take over 8; Former hopper 1 and charging adapter 8 are installed in the top and bottom of frame 2 respectively; In the outlet of the lower end of this former hopper 1 gate 3 is housed, this gate 3 is connected with a gate driving device 4.Described scale hooper 7 is installed in former hopper 1 and charging is taken between 8; One side of this scale hooper 7 is connected with an end of a lever 11, and the other end of this lever 11 is equipped with a fixed weight 12, and the fulcrum of this lever 11 is hinged on this frame 2 through fulcrum 9; On this lever 11, be provided with position-limit mechanism 10 up and down; The ceiling restriction fixed weight 12 of position-limit mechanism 10 is in jack-up moving counterweight 5 when upper up and down, but can not contact the lower end of counterweight support 6, and is as shown in Figure 2; The lower limit fixed weight 12 of position-limit mechanism 10 is in and does not contact down near switch 13 when the next up and down, leaves very little gap and gets final product, and is as shown in Figure 1.Below this fixed weight 12, be equipped with down near switch 13.

Above described fixed weight 12, be provided with moving counterweight 5, this moving counterweight 5 is made up of main body 52 and the undergauge slide bar 51 that is connected this main body lower end, and this undergauge slide bar 51 is supported on the described counterweight support 6 with longitudinal sliding.All be in when the next at this fixed weight 12 and moving counterweight 5; Leave working clearance S (3～5mm) between undergauge slide bar 51 lower ends of the top and moving counterweight 5 of this fixed weight 12; The lower end central authorities of this undergauge slide bar 51 are sphere or tip, below this moving counterweight 5, are provided with near switch 19.Described fixed weight 12 is oblate cylindricality (disk) shape with moving counterweight 5, and described undergauge slide bar 51 is cylindrical, and coaxial with moving counterweight 5.

The setting of working clearance S; Be in order to be in the next at moving counterweight 5; And during 51 times end in contact of the undergauge slide bar of the top of fixed weight 12 and moving counterweight 5; Make to be slightly larger than a distance of reaction near switch 13 and fixed weight 12 down that just working clearance S is a bit larger tham down the distance of reaction near switch 13.

The controlled end of described gate driving device 4, go up near switch 19 be connected with described controller 18 respectively near switch 13 down.Described controller 18 adopts microcomputer or Programmable Logic Controller.

Described gate driving device 4 adopts fluid cylinder, cylinder or electric device.

Speed probe 20 (being commonly called as meter counter) is housed on described carry-over pinch rolls 16, and speed probe 20 is connected with described controller 18.The rotating speed of the drive motors of carry-over pinch rolls 16 is controlled through frequency converter 22 by controller 18.

Rotating speed control to the drive motors of carry-over pinch rolls 16 also can not need speed probe 20 (referring to second embodiment shown in Figure 5).Export the rotating speed that the speed control frequency variation signals are controlled the drive motors of these carry-over pinch rolls 16 by described controller 18, calculate the product length of exporting in the unit interval through this rotating speed and carry-over pinch rolls 16 girths.Calculate and control extruder product length and uniformity thereof and compare with the mode of above-mentioned existing meter counter, have (having saved meter counter) simple in structure, measuring accuracy is high, practices thrift the advantage of cost.

In vertical hole of described counterweight support 6, linear bearing 61 is housed, this linear bearing 61 slides and inserts the undergauge slide bar 51 of described moving counterweight 5 lower ends, reduces the frictional resistance that undergauge slide bar 51 moves up and down, and improves control accuracy.

This embodiment takes over the outlet of 8 lower ends with its charging and directly is connected with the charging aperture 151 of extruder 15 through flange 21 when using.

Referring to Fig. 6, the third embodiment of the present invention is different with the moving counterweight 5 among first or second embodiment, and remainder is identical, and this identical part repeats no more.

The moving counterweight 5 of this embodiment, described moving counterweight 5 is made up of main body 25 and swing arm 26, and an end of this swing arm 26 is connected with this main body 5, and the other end is hinged through bearing 30 and described frame 1.Be provided with push rod 28 in the upper end of described fixed weight 12, roller (bearing) 29 is housed on the top of this push rod 28.All be in when the next at this fixed weight 12 and moving counterweight 5, leave working clearance S between the top of the roller 29 on this push rod and moving counterweight 5 following.

Also can in the swing arm 26 (or main body 25) of described moving counterweight 5, be provided with adjustable counterweight 27 and (change Different Weight and position as required; And with on fastening swing arm 26 of screw or the main body 25); Be used to regulate the weight (identical) of counterweight 5, to satisfy different metering needs with the counterweight effect of Libra.

The effect (operation principle) of the moving counterweight 5 of this embodiment is identical with the foregoing description; Just adopt swing arm 26 that the main body 25 of counterweight is connected with frame 1; It is more flexible to make that moving counterweight 5 moves up and down; Can not produce resistance owing to the error of mechanical engagement, it is also convenient more to install and transport.

Referring to Fig. 7, the above embodiment of the present invention is taken over the outlet of 8 lower ends with its charging and directly is connected with the charging aperture 151 of extruder 15 through flange 21 when using, be characterized in simple in structure.But owing to be directly to be connected with extruder 15, extruder 15 is the certain vibrations of generation when work, and the weighing precision of meausring apparatus is had certain influence.In order further to improve weighing precision, can be provided with in the bottom of frame 1 and surface-mounted support 31.The charging aperture 151 that 8 lower ends outlets and extruder 15 are taken in described charging is oppositely arranged but leaves gap (not shown), or the outlet of 8 lower ends is taken in described charging is connected (two ends of flexible pipe 23 are fastenedly connected with box cupling and charging adapter 8 and charging aperture 151 respectively) with the charging aperture 151 of extruder 15 through flexible pipe 23.Like this, because whole meausring apparatus and extruder 15 directly is not rigidly connected, greatly reduce the influence of the work vibrations of extruder 15 to the weighing precision of meausring apparatus.

The course of work of the present invention and control principle explanation be (producing plastic sheeting with first embodiment is example) as follows:

The original state of system is in former hopper 1, to fill raw material, the weight of the weight of fixed weight 12 and moving counterweight 5 according to designing requirement be configured (for example the weight of fixed weight 12 satisfy under scale hooper 7 does not have the situation of raw material or small number of materials, be in the next; And the weight W of moving counterweight 5 is chosen as required).

1, after extruder 15 unlatching work, down sends the signal of blowing, controller 18 regulating gate drive units 4 action starting gates 3 to controller 18 near switch 13; Raw material is full of scale hooper 7 very soon; (in this process, possible closing gate needed a process, is put into raw material in the scale hooper 7 probably greater than setting value after weight reached setting value; Each blowing amount exists than big difference); Scale hooper 7 downward fast moving are the next, and the fixed weight 12 of lever 11 is jack-up moving counterweight 5 upwards, and the two all becomes upper.Send near switch 19 on this moment and stop the blowing signal, controller 18 regulating gate drive units 4 action closed shutters 3.

2, along with the running of extruder 15; The material level of the raw material in the scale hooper 7 slowly descends; Fixed weight 12 descends with the moving counterweight 5 of its jack-up synchronously; When moving counterweight 5 is dropped to a certain setting height H2 by peak H1 (referring to Fig. 2 and Fig. 3), to go up and send the starting time signal near switch 19, controller 18 picks up counting.Height H 2 is last distance of reaction near switch 19, selects to go up the distance of reaction near switch 19 as required, and general 3-5mm gets final product.

3, along with the running of extruder 15; The material level of the raw material in the scale hooper 7 continues to descend; Fixed weight 12 descends with the moving counterweight 5 of its jack-up synchronously; When moving counterweight drops to 6 last times of counterweight support for 5 times, but because fixed weight 12 weight of the weight of the raw material in this moment scale hooper 7 during greater than poised state, so undergauge slide bar 51 lower ends of the top and moving counterweight 5 of fixed weight 12 do not disengage; Fixed weight 12 following with down near the spacing of switch 13 greater than working clearance s, do not have induced signal output (referring to Fig. 4) near switch 13 below the institute.

4, during the fixed weight 12 when the raw material weight in the scale hooper 7 is lower than poised state, fixed weight 12 descends and breaks away from moving counterweight 5, and this sends the terminal time signal near switch 13 at present, and controller 18 timing finish, and the timing duration is T.[wherein W is the raw material weight (equilibrium relation according to the sky chessboard is calculated) in the scale hooper 7 that measured of moving counterweight 5 to the use amount of raw material in the 18 unit of account times of controller (being the raw material weight that gets into extruder in the unit interval) for W/ T; The weight that also can be designed to counterweight 5 equals the weight of raw material in the scale hooper 7, the weight of W=counterweight 5 at this moment]; Meanwhile, down send the signal of blowing near switch 13 to controller 18, controller 18 regulating gate drive units 4 action starting gates 3 continue the next course of work (referring to Fig. 1).

Because the timing node that said process is a collection activity counterweight 5 when dropping to ad-hoc location with fixed weight 12; And no matter be put into during original state in the scale hooper 7 raw material greater than setting value than big difference; The blowing weight that promptly exceeds when H1 (be higher than the situation of H2 corresponding to moving counterweight 5, i.e.) not memory has only when moving counterweight 5 drops to height H 2 by peak H1 in controller 18; Go up and just send the starting time signal near switch 19, controller 18 picks up counting.So this device has improved control accuracy.

The present invention utilizes the uniformity control principle of the use amount W/ T of raw material in the unit interval to extruder discharging (film) 17 unit weights, and brief description as follows.

Because extruder do not have raw material in the scale hooper 7 when original state, so that fixed weight 12 1 ends of lever 11 are under the effect of gravity is the next, scale hooper 7 is in upper.On controller 18, set every meter weight A of (input) product, like 1 gram/rice.If extruder uses the raw material weight W=1000g of a scale hooper 7.

Controller 18 calculates the employed duration T of raw material that extruder is whenever extruded a scale hooper 7; If this duration T is steady state value (as 50 seconds), then controller 18 is controlled carry-over pinch rolls 16 according to certain rotation speed operation according to the product parameters of setting (film thickness or rice/gram).According to the above-mentioned parameter that provides; Extruder per second load B=W/T=1000/50=20g/s; With the every meter weight A (1g/m) of extruder per second load B (20g/s) divided by product; The rotating speed V that promptly obtains carry-over pinch rolls 16 should be 20m/s, and controller 18 is adjusted into 20m/s according to the rotating speed of the carry-over pinch rolls 16 that speed probe 20 detects to it.

Perhaps controller 18 is directly adjusted the rotating speed of the drive motors of carry-over pinch rolls 16 through controlling frequency converter 22, reaches the identical purpose that detects and adjust carry-over pinch rolls 16 rotating speeds with speed probe 20.Its operation principle is the frequency signal that controller 18 directly obtains frequency converter 22; Adjust and calculate the rotating speed of the drive motors of carry-over pinch rolls 16 thus; Go out the rotating speed of carry-over pinch rolls 16 again according to the speed ratio calculation of the drive motors of carry-over pinch rolls 16 and carry-over pinch rolls 16, the girth that multiply by carry-over pinch rolls 16 by the rotating speed of these carry-over pinch rolls 16 can obtain the per second length of extruded product.The rotating speed of the drive motors through frequency converter 22 control carry-over pinch rolls 16 has overcome meter counter measurement products length because the alignment error or the error of sliding and producing can obviously improve control accuracy.

When the rotating speed of extruder reduces owing to a variety of causes (impurity putty variation etc. being arranged like voltage pulsation or plastics); Make charging rate slack-off; Above-mentioned duration T prolongs (like 55s); The degree that this moment, controller 18 prolonged according to this duration calculates the rotating speed V=1000/55/1=18.18m/s of carry-over pinch rolls 16, reduces rotating speed; Or the rotating speed of raising extruder motor 14, to satisfy the requirement of every meter weight A=1g/m, keep the thickness of membrane even.

If the rotating speed of extruder accelerates; Then charging rate improves; Cause described duration T to shorten (like 45s), the degree that this moment, controller 18 shortened according to this time interval calculates the rotating speed V=1000/45/1=22.22m/s of carry-over pinch rolls 16, improves the rotating speed of carry-over pinch rolls 16; Or the rotating speed of reduction extruder motor 14, to satisfy the requirement of every meter weight A=1g/m, adjust film thickness automatically thereby reach, make it keep uniform purpose.

The most outstanding characteristics of the present invention are to have adopted cooperatively interacting of fixed weight 12 and moving counterweight 5; Can realize record acquisition, thereby can calculate " getting into the interior raw material weight of extruder in the unit interval " the duration in initial stage (picking up counting) of the raw material in each scale hooper 7 that is full of and latter stage (timing finishes) at every turn.If have only a fixed weight when (be equivalent to fixed weight 12 and be one with moving counterweight 5), after in scale hooper 7, being full of raw material (as 5 kilograms), it is the next that scale hooper 7 becomes, and upward sends near switch 19 to stop the blowing signal, and gate 3 is closed; Running along with extruder 15; The material level of the raw material in the scale hooper 7 slowly descends; When counterweight is dropped to a certain setting height H2 by peak H1 (as the raw material that is equivalent in the scale hooper 7 is 4.5 kilograms), to go up and send the time zero signal near switch 19, controller 18 just picks up counting.But; Raw material in the scale hooper 7 is when this weight, and scale hooper 7 promptly can be changed into upper, and counterweight becomes the next; This promptly is triggered near switch 13 at present; Controller 18 starting gates, 3 blowings (picking up counting simultaneously), and this moment, scale hooper 7 interior raw materials only got into the extruder sub-fraction, the duration of timing is zero basically.So can not realize calculating the function of " getting into the raw material weight in the extruder in the unit interval ".

And fixed weight 12 of the present invention only the raw material in scale hooper 7 use up basically in (having only sub-fraction), just can become under the next triggering near switch 13 by upper, timing just can finish.Begin to end from timing, the raw material that gets in the extruder is slightly less than scale hooper 7 raw material weights that are full of.And the raw material weight that begins in the duration of end, to get in the extruder from timing is (equation of equilibrium according to the sky chessboard calculates the weight of counterweight 5 and the weight relationships of scale hooper 7 interior raw materials) of the weight decision of fixed weight 12 and moving counterweight 5.Can change the weight of counterweight 5 as required.The input of W value is stored into controller 18, accomplishes the calculating and the The whole control work of " getting into the raw material weight in the extruder in the unit interval " by the program of controller 18 automatically.

The present invention also can be used for the application form of multimachine co-extrusion, and (many extruders are from an extrusion discharging; Shared one group of carry-over pinch rolls); Every extruder uses cover control device of the present invention separately; The rotating speed of the mean value control carry-over pinch rolls of the W/T data of gathering with every extruder, control principle is identical with above-mentioned single machine.Weighing precision of the present invention can reach 5/10000ths, improves an one magnitude than prior art.

Claims

1. the high precision in control device of an extruder discharging unit weight; Comprise controller and meausring apparatus; The input of this controller is connected with meausring apparatus; The output of this controller is connected with the drive motors of the extruding screw of extruder or the drive motors of carry-over pinch rolls, and described meausring apparatus comprises former hopper, frame, scale hooper and charging adapter, and the top and bottom that are installed in frame are respectively taken in former hopper and charging; In the outlet of the lower end of this former hopper gate is housed, this gate is connected with a gate driving device; Described scale hooper is installed between former hopper and the charging adapter; One side of this scale hooper is connected with an end of a lever; The other end of this lever is equipped with a fixed weight, and the fulcrum of this lever is hinged on this frame, on this lever, is provided with position-limit mechanism up and down; Below this fixed weight, be equipped with down near switch; It is characterized in that: above described fixed weight, be provided with moving counterweight, this moving counterweight is supported on the counterweight support versatilely, below this moving counterweight, is provided with near switch; The controlled end of this gate driving device, go up near switch be connected with described controller respectively near switch down.

2. the high precision in control device of extruder discharging unit weight according to claim 1; It is characterized in that: described moving counterweight is made up of main body and the undergauge slide bar that is located at this main body lower end; This undergauge slide bar is supported on the described counterweight support with longitudinal sliding; All be in when the next at this fixed weight and moving counterweight, leave the working clearance between the undergauge slide bar lower end of the top and moving counterweight of this fixed weight; The lower end central authorities of this undergauge slide bar are sphere or tip.

3. the high precision in control device of extruder discharging unit weight according to claim 2; It is characterized in that: be provided with vertical hole at described counterweight support; Vertically linear bearing is equipped with in the hole in this, in the centre bore of this linear bearing, inserts the undergauge slide bar of described moving counterweight lower end with being slidingly matched.

4. the high precision in control device of extruder discharging unit weight according to claim 3 is characterized in that: described moving counterweight is discoid, and described undergauge slide bar is cylindrical, and coaxial with this moving counterweight.

5. the high precision in control device of extruder discharging unit weight according to claim 1 is characterized in that: described moving counterweight is made up of main body and swing arm, and an end and the described frame of this swing arm are hinged, and the other end is connected with this main body; Upper end in described fixed weight is provided with push rod, on the top of this push rod roller is housed; All be in when the next at this fixed weight and moving counterweight, leave the working clearance between the top of the roller on this push rod and moving counterweight following.

6. the high precision in control device of extruder discharging unit weight according to claim 5 is characterized in that: in the main body of described moving counterweight or swing arm, be provided with adjustable counterweight.

7. the high precision in control device of extruder discharging unit weight according to claim 1 is characterized in that: described gate driving device adopts fluid cylinder, cylinder or electric device; Described controller adopts microcomputer or Programmable Logic Controller.

8. the high precision in control device of extruder discharging unit weight according to claim 1 is characterized in that: on described carry-over pinch rolls, speed probe is housed, and is connected with described controller.

9. the high precision in control device of extruder discharging unit weight according to claim 1 is characterized in that: the output of described controller is connected with the drive motors of described carry-over pinch rolls through frequency converter, has saved speed probe.

10. the high precision in control device of extruder discharging unit weight according to claim 1 is characterized in that: be provided with and surface-mounted support in the bottom of described frame; The charging aperture that lower end outlet and extruder are taken in described charging is oppositely arranged but leaves the gap, or the lower end outlet is taken in described charging is connected with the charging aperture of extruder through flexible pipe.