JP2003062891A - Extrusion-molding facilities - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the high product quality and shape size precision and the stable operation of facilities for a long time, even when a raw material for a resin includes a large amount of a recycled raw material. SOLUTION: The extrusion-molding facilities comprise a first screen replacement unit 5, a first geared pump 6, a unit group 7 with an arrangement of a second and a third screen replacement units 7A and 7B and a geared pump group 8 with an arrangement of a second and a third geared pumps 8A and 8B in series, sequentially disposed between an extruder 1 and a die 4. In addition, a first to a third screen changer control parts 21 to 23 which output a screen backward washing instruction or a screen replacing instruction to the screen replacement units 5, 7A and 7B based on a resin pressure at the inlets of screen replacement units 5, 7A and 7B, the pressure control part 24 of the extruder 1 which controls the screw rotating speed of the extruder 1 based on a resin pressure at the outlet of the first screen replacement unit 5 and the pressure control part 25 of the first geared pump 6 which controls the rotating speed of the first geared pump 6 based on a resin pressure at the outlet of the unit group 7, are arranged.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a recycled raw material 1
The present invention relates to an extrusion molding facility that heats and melts a thermoplastic resin raw material, which is dominated by 100% or recycled raw materials, by an extruder, kneads the mixture, and extrudes it by a die.

[0002]

2. Description of the Related Art Conventionally, as a screen unit equipped in an extrusion molding facility, there is a screen exchange unit with a backwash mechanism which removes clogged foreign matter by circulating resin in the reverse direction. However, when the screen is backwashed, there is a problem that the resin pressure at the outlet of the screen replacement unit varies and the accuracy of the product molded by the die decreases, and the yield of the product deteriorates. Japanese Patent Laid-Open No. 2001-30338 (Japanese Patent Application No. 11-2069)
No. 49) has proposed an extrusion molding equipment capable of eliminating the fluctuation of the resin pressure generated when the screen of the screen exchange unit is replaced by controlling the extruder based on the resin pressure at the inlet of the gear pump.

[0003]

However, in the above-mentioned extrusion molding equipment, although there is no problem in the case of resin raw materials in which the ratio of virgin raw materials and recycled raw materials is small, 100% recycled raw materials and many recycled raw materials (eg 50% recycled raw materials). Above), the amount of dust, foreign matters, deteriorated substances, and impurities contained in the raw material is extremely large, so that the frequency of replacement of the screen (the frequency of backwashing) increases and the degree of cleaning of the screen by backwashing decreases. Further, due to frequent pressure fluctuations, the quality and shape of the product become unstable, and stable operation for a long period of time becomes impossible.

The present invention solves the above problems and makes 100% recycled raw materials or 50% recycled raw materials.
It is an object of the present invention to provide an extrusion molding facility that has high product quality and high accuracy of shape and dimension even with the resin raw materials included above, and that enables stable operation for a long period of time.

[0005]

To achieve the above object, the invention according to claim 1 is a screen exchange unit having a backwash function and / or an exchange function in a resin passage extending from an extruder to a molding die. In the extrusion molding equipment arranged in a plurality of stages, in the resin passage of the extruder outlet, an inlet screen exchange unit and an inlet gear pump are provided in order, on the inlet side of the resin passage from the inlet gear pump to the molding die, A unit group in which a plurality of screen replacement units are arranged in series is arranged, and a gear pump group in which a plurality of gear pumps are arranged in series is arranged on the outlet side, and the screen replacement units are arranged on the basis of the resin pressure at the inlet of each screen replacement unit. A screen changer control unit that outputs a backwash command or a replacement command for the screen is provided,
An extruder pressure control unit for controlling the screw rotation speed of the extruder based on the resin pressure at the outlet of the inlet screen exchange unit is provided, and the rotation speed of the inlet gear pump is controlled based on the resin pressure at the outlet of the unit group. A pre-stage gear pump pressure control unit is provided.

According to the above construction, the screen exchange units arranged in a plurality of stages at the inlet and the unit group can effectively trap dust, foreign matters, deteriorated substances and impurities contained in the resin raw material. In addition, fluctuations in resin pressure that occur each time the screen is backwashed or replaced can be effectively suppressed by the multiple-stage gear pump and the extruder pressure control unit and the gear pump control unit that control the rotation speed of the extruder and gear pump. it can. Therefore, much dust and foreign matter,
Even recycled materials containing deteriorated materials and impurities can be effectively removed of dust, foreign materials, deteriorated materials and impurities, and the resin can be supplied to the molding die at a stable resin pressure. The quality and shape and dimension accuracy are also high, which enables stable operation for a long time.

According to a second aspect of the present invention, in the configuration of the first aspect, the last stage gear pump of the gear pump group is configured to be driven at a constant rotation speed, and the gear pumps other than the last stage gear pump of the gear pump group are: A rear gear pump pressure control unit for controlling the rotation speed based on the resin pressure at the outlet is provided.

According to the above construction, a large fluctuation of the resin pressure caused by backwashing or replacement of the unit group can be effectively suppressed by the rear gear pump pressure control section, so that the last gear pump is rotationally controlled. The resin can be supplied to the molding die without the need for stable, continuous operation for a longer period of time.

According to the third aspect of the present invention, there is provided an extrusion molding facility in which a screen exchange unit having a backwash function and / or an exchange function is arranged in a plurality of stages in a resin passage extending from a screw type extruder to a molding die. In the resin passage, the screen replacement units are arranged in a plurality of stages, and a gear pump is provided at the outlet of each screen replacement unit, and the screen replacement unit reverses the screen based on the resin pressure at the inlet of each screen replacement unit. A screen changer control unit that outputs a washing command or a replacement command is provided, and an extruder pressure control unit that controls the screw rotation speed of the extruder is provided based on the resin pressure at the exit of the screen exchange unit at the front stage. Based on the resin pressure at the outlet of the gear pump, the rotation speed of the gear pump at the last stage is adjusted. A molding pressure control unit to control the gear pump pressure control unit that controls the rotation speed of the gear pump arranged at the inlet of the screen exchange unit based on the resin pressure at the outlet of the screen exchange unit other than the first and last stages. It is provided.

According to the above construction, the screen replacement units are arranged in a plurality of stages in the resin path, and the gear pumps are arranged at the inlets of the respective screen replacement units. The extruder pressure control unit that can effectively capture the contained dust, foreign substances, deteriorated products, and impurities, and controls the screw rotation speed of the extruder, the gear pump control unit that controls the rotation speed of the gear pump, and the last stage With the molding pressure control unit that controls the rotation speed of the gear pump, it is possible to effectively suppress the fluctuation of the resin pressure that occurs each time the screen is backwashed or replaced. Therefore, even if it is a recycled material containing a lot of dust, foreign substances, deteriorated substances, and impurities, it is possible to effectively remove dust, foreign substances, deteriorated substances, and impurities.
Since the resin can be supplied to the molding die with a stable resin pressure, the quality of the molded product and the accuracy of the shape and dimension are high, and stable operation for a long time becomes possible.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Here, a first embodiment of an extrusion molding equipment according to the present invention will be described with reference to FIGS.

The first embodiment of this extrusion molding equipment is as follows:
The present invention relates to a triple screen changer in which a screen exchange unit and a gear pump are arranged in series in three stages, and a triple gear pump type. In FIG. 1, 1
Is a single-screw or multi-screw screw type extruder, which heats and melts the resin raw material supplied from the screw type raw material supply feeder 2 to the casing 1a by a heating device (not shown), and a screw drive device (electric motor) 3, the kneading screw 1b is rotated and kneaded. Although the raw material supply feeder 2 has shown the raw material quantitative supply type in which all the resin raw materials fed from the raw material supply feeder 2 are received in the extruder (such as a twin-screw type) 1, the raw material hopper is replenished with the raw material and the extrusion is performed. A machine (usually a single-screw type) 1 may receive a fixed amount according to the rotation speed of the screw 1b.

In the resin passage extending from the extruder 1 to the molding die 4, there is provided a first screen exchange unit (inlet screen exchange unit) 5 having a plurality of screens and a resin pressure is kept constant and pressure fluctuations are alleviated. First to do
A unit group 7 having a gear pump (inlet gear pump) 6, a second screen exchange unit (previous stage screen exchange unit) 7A and a third screen exchange unit (second stage screen exchange unit) 7B, and a first gear pump 8
A and a gear pump group 8 having a second gear pump (last-stage gear pump) 8B are arranged in series from the inlet to the outlet.

Then, in the resin passage, from the extruder 1 to the first
First resin conduit 1 connected to screen exchange unit 5
1. Second resin conduit 12 connected from the first screen replacement unit 5 to the first gear pump 6, third resin conduit 13 connected from the first gear pump 6 to the second screen replacement unit 7A, second screen replacement unit 7A From the third
A fourth resin conduit 14 connected to the screen replacement unit 7B, a fifth resin conduit 15 connected to the second gear pump 8A from the third screen replacement unit 7B, and a sixth resin conduit 8 connected to the third gear pump 8B from the second gear pump 8A. The resin conduit 16 is provided with first to sixth pressure gauges 9A to 9F for measuring the resin pressure, respectively.

The extrusion control device 20 for controlling the extrusion molding equipment causes the screen replacement unit 5 to backwash the screen when the resin pressure flowing into the first screen replacement unit 5 by the first pressure gauge 11 becomes a predetermined value or more. First screen changer control unit 21 that outputs a command or a replacement command
Then, when the resin pressure flowing into the second screen replacement unit 7A by the third pressure gauge 9C exceeds a predetermined value, a second screen changer control that outputs a screen replacement command and a backwash command to the second screen replacement unit 7A. Part 22
And when the resin pressure flowing into the third screen replacement unit 7B by the fourth pressure gauge 9D exceeds a predetermined value, a third screen changer control for outputting a screen replacement command and a backwash command to the third screen replacement unit 7B. Part 23
And are provided.

The first screen changer control unit 2
P based on the backwash command or replacement command of the screen output from No. 1 and the pressure fluctuation of the resin discharged from the first screen replacement unit 5 detected by the second pressure gauge 9B.
An extruder pressure control unit 24 that outputs a screw rotation speed control command to the screw drive device 3 by ID control is provided, and the second and third screen changer control units 22 and 23 are provided.
Based on the backwash command or replacement command of the screen output from the second screen replacement unit 7B and the pressure fluctuation of the resin discharged from the second screen replacement unit 7B detected by the fifth pressure gauge 9E.
A first gear pump pressure control section (previous stage gear pump pressure control section) 25 that outputs a gear rotation speed control command to the first gear pump 6 by PID control is provided. In addition, the second gear pump pressure control unit (the latter gear pump pressure control unit that outputs a control command of the gear rotation speed of the second gear pump 8A based on the pressure fluctuation of the resin discharged from the second gear pump 8A by the sixth pressure gauge 9F). ) 26 are provided. The third gear pump 8B at the final stage is maintained at a constant rotation speed so that a preset resin pressure can be obtained.

Further, a control signal is output to the screw driving device 2a of the raw material supply feeder 2 on the basis of the signal from the rotation detector PG of the kneading screw 1b provided in the screw driving device 3 to control the rotation speed of the screw 2b. A feeder control unit 27 that controls the amount of raw material supply is provided.

By the way, in the above extrusion molding equipment, when the resin temperature is constant (the temperature change is small), the variation value ΔP of the inlet pressure of the gear pump 5 (detected pressure value-steady pressure value).
And the extrusion amount Q of the extruder 1 have a proportional relationship of ΔP = K × Q, and the extrusion amount Q and the rotation speed Ns of the screw 1c.
Are proportional. Therefore, for example, the pressure control unit 24 performs proportional-integral control such that the rotation speed Ns is decreased when the fluctuation value ΔP increases and the rotation speed Ns is increased when the fluctuation value ΔP decreases.

The screen exchange units 5 and 7 shown in FIG.
A and 7B have the same structure, and as shown in FIG. 2, two slide holes 31A and 3A formed in the unit main body 30.
1B, the first and second piston portions 32A, 32B are slidable and detachably attached to a screen 35Aa to be described later.
35Bb is arranged to be replaceable. Then, the switching actuators 33A and 33B cause the first and second piston portions 32A and 32B to move to the first backwash positions Aa and B, respectively.
a, the non-backwashing positions Ab and Bb, and the second backwashing positions Ac and Bc. The first and second piston portions 32
A and 32B have two resin inlets 34Aa, 34Ab,
One resin outlet 34Ac, 34 from 34Ba, 34Bb
T-shaped mixing passages 34A, 34B connected to Bc are formed, and their resin inlets 34Aa, 34Ab, 34Ba, 3 are formed.
4Bb includes first and second screens 35Aa and 35Ab including a breaker plate and a mesh screen in front of the breaker plate.
And third and fourth screens 35Ba and 35Bb are respectively arranged. Then, the first and second piston portions 32
When A and 32B are in the non-backwash positions Ab and Bb, four inflows connected from the first, third and fourth resin conduits 11, 13 and 14 via branch passages (conduit) 40a to 40c. The passages 36Aa, 36Ab, 36Ba, 36Bb are the resin inlets 34Aa, 3 of the mixing passages 34A, 34B, respectively.
4Ab, 34Ba, 34Bb, and second, fourth and fifth resin conduits 1 from the resin outlets 34Ac, 34Bc through the discharge passages 37A, 37B and the confluence passage 38.
2, 14, 15 are connected.

In order to discharge the contaminated resin after backwashing,
A first waste passage 39Aa is formed to communicate with the first screen 35Aa via the resin inlet 34Aa when the first piston portion 32A is switched to the first backwash position Aa. Then, when the second piston portion 32B is switched to the first backwash position Ba, a third waste passage 39Ba that is communicated with the third screen 35Ba via the resin inlet 34Ba is formed. Further, when the first piston portion 32A is switched to the second backwash position Ac, the second screen 35A
A second waste passage 39Ab is formed so as to communicate with b via the resin inlet 34Ab. Furthermore, the second backwash position B
A fourth waste passage 39Bb is formed to communicate with the fourth screen 35Bb via the resin inlet 34Bb when the second piston portion 32B is switched to c.

Therefore, the first and second piston portions 32
During normal operation in which A and 32B are in the non-backwash positions Ab and Bb, respectively, the inflow passages 36Aa, 36Ab, 36Ba,
36Bb to resin inlets 34Aa, 34Ab, 34Ba,
Resin is sent to 34Bb and the first to fourth screens 35A
Each of a to 35Bb is filtered to remove dust, foreign matters, deteriorated substances, and impurities. And the resin outlet 34A
c, 34Bc through the discharge passages 37A, 37B and the merging passage 38, the second, fourth, fifth resin conduits 12, 14,
Extruded to 15.

Further, the switching actuators 33A and 33B are driven by the backwash command, and the first and second piston portions 32 are driven.
When A and 32B are slid to the first backwash positions Aa and Ba, respectively, as shown in FIG.
The resin is sent from 6Bb to the resin inlets 34Ab and 34Bb, and dust, foreign matters, deteriorated substances, and impurities are removed by the second and fourth screens 35Ab and 35Bb. Then, a part of the resin flows back through the first and third screens 35Aa and 35Ba to remove foreign substances that have become clogged and to be accompanied,
It is discharged to the outside from the third disposal passages 39Aa and 39Ba. The remaining resin is extruded from the resin outlets 34Ac and 34Bc into the gear pump inlet conduit 8 through the confluence passage 38.

Further, the first and third screens 35Aa, 3
After backwashing 5Ba for a predetermined time, the switching actuators 33A and 33B are driven by the backwash command to drive the first and second actuators.
The second piston portions 32A and 32B are located at the second backwash positions Ac and B.
When it is slid to c, as shown in FIG.
Resin is sent from 6Aa, 36Ba to the resin inlets 34Aa, 34Ba, and the first and third screens 35Aa, 35Ba are supplied.
This removes dust, foreign substances, deteriorated materials and impurities. And, a part of the resin is used for the second and fourth screens 35Ab, 3
The 5Bb is backflowed to remove the clogged foreign matter and the like, and is entrained, and is discharged to the outside from the second and fourth disposal passages 39Ab and 39Bb. The remaining resin is the resin outlets 34Ac, 34
It is pushed out from Bc to the gear pump inlet conduit 8 via the confluence passage 38.

The screen replacement units 5, 7A,
The screens 35Aa to 35Bb of 7B are set so that the mesh becomes smaller from the upstream side to the downstream side, and dust, foreign matters, deteriorated substances, and impurities are removed from the upstream side to the downstream side in descending order.

In the above explanation of the operation, the two screens are backwashed at the same time. However, in order to reduce the pressure fluctuation, they are actually carried out one by one. When the screen replacement command is output, the operator is notified by a display device or alarm device arranged on the control panel, etc.
Replacement work of the second piston portions 32A and 32B is performed.
This replacement work is performed by the first and second piston portions 32A and 32B.
Although the screens 35Aa to 35Bb are not sequentially replaced and the resin molding is not stopped, the fluctuation of the resin pressure during the replacement work is the largest.

In the above structure, the resin raw material is supplied from the raw material supply feeder 2 to the extruder 1, heated and melted by the heating device, and kneaded by the kneading screw 1b. Then, from the first screen replacement unit 5 to the first
After being sent to the second screen replacement unit 7A and the third screen replacement unit 7B that form the unit group 7 via the gear pump 6 to remove dust, foreign matter, deteriorated materials, and impurities, the first gear pump of the gear pump group 8 8A and the second gear pump 8B to be supplied to the molding die 4 and molded into a predetermined shape.

At this time, in the first to third screen exchange units 5, 7A and 7B, the screen 3 is sequentially cleaned from the dust, foreign substances, deteriorated substances and particles having large impurities removed by filtration.
5Aa to 35Bb are accumulated to increase the resin pressure on the inlet side. When the first pressure gauge 9A detects that the resin pressure in the first resin conduit 11 has become equal to or higher than a predetermined value, the first screen changer control unit 21 causes the first screen replacement unit 5 and the extruder pressure control unit 24 to operate. The screen backwash command or replacement command is output to. Also, the third pressure gauge 9
When the resin pressure detected by C exceeds a predetermined value, the second
The screen changer controller 22 outputs a screen backwash command or a screen replacement command to the second screen replacement unit 7A and the gear pump pressure controller 25. Furthermore, the fourth
When the resin discharge pressure detected by the pressure gauge 9D exceeds a predetermined value, the third screen changer control unit 22 causes
Screen replacement unit 7B and gear pump pressure control unit 2
An instruction to backwash the screen or an instruction to replace the screen is output to 5.

In the first to third screen exchange units 5, 7A and 7B, the switching actuators 33A and 33B are operated by the backwash command signal so that the first and second piston portions 32A and 32B move in the first reverse direction. The resin is passed in the opposite direction to the screens 35Aa to 35Bb by sequentially sliding from the wash positions Aa and Ba to the second backwash positions Ac and Bc, so that dust, foreign matters, and deteriorated substances accumulated on the screens 35Aa to 35Bb are collected. , Impurities are removed.

When the backwashing of the screens 35Aa to 35Bb is repeated, only the backwashing of the screens 35Aa to 35Bb.
If the 35Bb dust, foreign matter, deteriorated matter, and impurities cannot be sufficiently removed and the resin pressure is not improved, or if the resin pressure is abnormally high, the first to third screen changer control units 21 to 23 A screen replacement command is issued to the first to third screen replacement units 5, 7A, 7B.

In the extruder pressure control unit 24, the screw drive unit 3 of the extruder 1 is controlled by PID control based on the backwash signal from the first screen changer control unit 21 and the detection value of the second pressure gauge 9B. The rotation speed is controlled and the amount of resin discharged is controlled. At the same time, the feeder control unit 27 also adjusts the feed rate (amount) of the feed by the feed feeder 2. Further, the resin pressure at the inlet of the second gear pump 8A fluctuates due to backwashing action of the second and third screen replacement units and screen replacement, or fluctuation of the rotation speed (discharge pressure) of the first gear pump 6, In the first gear pump pressure control unit 25, based on the control signals of the second and third screen changer control units 22 and 23 and the resin pressure detected by the third pressure gauge 9D and the fourth pressure gauge 9E,
The rotational speed of the first gear pump 6 is feedback-controlled with respect to the set reference value.

When a variation in the resin pressure on the inlet side of the third gear pump 8B is detected by the sixth pressure gauge 9F, a rotation speed command is sent from the second gear pump controller 26 to the second gear pump 8A based on the detected value. Is output and controlled, the fluctuation of the resin pressure is blocked and stabilized. As a result, the rotation speed of the third gear pump 8B at the final stage is maintained at a constant value, so that the resin can be supplied to the molding die 4 with a stable resin pressure.

According to the above embodiment, the first to third screen exchange units 5 and 7 in which the mesh becomes finer one after another
In A and 7B, if the screen backwashing interval is set to an appropriate frequency, pressure fluctuations that occur during screen backwashing of the first screen replacement unit 5 in the first screen replacement unit 5 (resin to be backwashed and replaced) The pressure setting value is the largest, but the pressure increase by the first screen exchange unit 5 is detected by the first pressure gauge 11 and the extruder pressure control unit 24 reduces the pressure fluctuation so that the screw of the extruder 1 is reduced. By controlling the rotation speed,
It is possible to suppress pressure fluctuations at the inlet of the gear pump 6. Further, the resin discharged from the first screen exchange unit 5 is passed through the first gear pump 6 and the screens 35Aa to 35 of the second and third screen exchange units 7A and 7B are sent.
By passing Bb, dust, foreign matters, deteriorated substances, and impurities are effectively removed in order of large particles, and the die 4
Thus, it is possible to perform good molding and to continuously operate. Here, the number of screen replacement units at the exit of the extruder 1 is one, so there is less pressure fluctuation when the screen is clogged than when multiple units are arranged (the set value of resin pressure for backwashing and replacement can be reduced). In addition, the vent-up phenomenon can be prevented, and the pressure fluctuation during screen replacement does not become too large and uncontrollable.

Also, the second and third screen exchange units 7
Even if the resin pressure may fluctuate due to backwashing of screens A and 7B or screen replacement, the second gear pump 8
The resin pressure at the inlet of A is detected by the fifth pressure gauge 9E and feedback control of the first gear pump 6 is performed by the first gear pump pressure control unit 25 to effectively suppress the pressure fluctuation, and further, the third gear pump 8B inlet. Of the second gear pump pressure controller 2 by detecting the pressure fluctuation of the second pressure gauge 9F.
By controlling the rotation speed of the second gear pump 8A by 6, it is possible to effectively suppress the fluctuation of the resin pressure and maintain the uniform resin pressure. As a result, by keeping the third gear pump 8B at the final stage at a constant rotation speed,
Further, the resin can be supplied to the molding die 4 with a stable resin pressure, and the pressure fluctuations of the two second and third screen replacement units 7A and 7B that are continuously arranged can be effectively suppressed.

Therefore, even if 100% recycled raw material or recycled raw material containing more than 50% impurities or dust, the impurities can be satisfactorily removed by the screen replacement units 5, 7A, 7B arranged in a plurality of stages. It is possible to effectively suppress fluctuations in resin pressure during backwashing or replacement of the screen, enabling continuous extrusion molding, stabilizing product quality and shape dimensions, and enabling long-term continuous operation. Becomes

Next, a second embodiment of the extrusion molding equipment will be described with reference to FIG. The same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. This extrusion equipment is suitable for medium and low viscosity resin raw materials that contain a lot of impurities and dust.
As a set, it relates to a double screen changer and a double gear pump type arranged in series in a plurality of stages (two stages in the figure). The resin passage from the extruder 1 to the molding die 4 has a first screen exchange unit 5, 1 gear pump 6, 2nd screen exchange unit 51 and 2nd gear pump 5 of the same structure as said 1st screen exchange unit 5
2 are sequentially arranged in series.

Further, in the extrusion control device 50, when the detection value of the first pressure gauge 9A provided in the first resin passage 11 at the inlet of the first screen exchange unit 5 exceeds a predetermined value, the first screen exchange unit 5 is notified. First screen changer control unit 21 that outputs a backwash command or a replacement command for the screen
And when the detected value of the third pressure gauge 9C provided in the third resin passage 13 at the inlet of the second screen replacement unit 51 exceeds a predetermined value, the second screen replacement unit 51 is instructed to backwash or replace the screen. And a second screen changer controller 53 for outputting

Further, based on the screen backwash command or replacement command output from the first screen changer controller 55 and the fluctuation of the resin pressure at the outlet of the first screen replacement unit 5 detected by the second pressure gauge 9B. , PI
An extruder pressure control unit 24 that outputs a screw rotation speed control signal to the screw drive device 3 of the extruder 1 by D control is provided. Furthermore, the PID control is performed based on the backwash command or replacement command of the screen output from the second screen changer control unit 53 and the fluctuation of the resin pressure at the outlet of the second screen replacement unit 51 detected by the fourth pressure gauge 9D. Accordingly, a gear pump pressure control unit 54 that controls the rotation speed of the first gear pump 6 is provided. Further, a molding pressure control unit 55 that controls the rotation speed of the gear pump 52 based on the resin pressure at the outlet of the second gear pump 52 is provided.

In the above structure, the resin raw material is supplied from the raw material supply feeder 2 to the casing 1a of the extruder 1 and is heated and melted by the heating device and the kneading screw 1b.
It is kneaded by. Then, the melted resin material is introduced into the first screen replacement unit 5 and the screen 3
By passing 5Aa to 35Bb, dust, foreign matter,
Deteriorated products and impurities are removed. Further, the resin is introduced from the first gear pump 6 to the second screen replacement unit 51 to remove dust, foreign matters, deteriorated substances and impurities, and then supplied to the molding die 4 via the second gear pump 52 to have a predetermined shape. Molded.

At this time, in the first and second screen exchange units 5 and 51, the dust, foreign matters, deteriorated substances and impurities removed by filtration are accumulated in the screens 35Aa to 35Bb to increase the resin pressure on the inlet side. The first pressure gauge 9A detects the resin pressure at the inlet of the first screen exchange unit 5,
When this exceeds a predetermined value, the first screen changer controller 21 outputs a screen backwashing command or a screen replacement command to the first screen replacement unit 5 and the extruder pressure controller 24. Further, the third pressure gauge 9C detects the resin pressure at the inlet of the second screen exchange unit 51, and when the resin pressure exceeds a predetermined value, the second screen changer control unit 22 causes the second screen exchange unit 51 and the gear pump pressure to be exceeded. A screen backwash command or a screen replacement command is output to the control unit 54.

Then, in the first and second screen exchange units 5 and 51, the switching actuators 33A and 33B are actuated by the backwash command signal so that the first and second piston portions 32A and 32B move to the first backwash position. Aa, Ba and second
The screen 35A is slid to the backwash positions Ac and Bc.
By passing the resin in the opposite direction to a to 35Bb, dust, foreign matters, deteriorated substances, and impurities accumulated on the screens 35Aa to 35Bb are removed.

Further, the screen 35Aa-
If the 35Bb dust, foreign substances, deteriorated substances, and impurities cannot be sufficiently removed and the resin pressure is not improved, or if the resin pressure is abnormally high, the first and second screen changer control units 21 to 23 A screen exchange command is issued to the first to third screen exchange units 5 and 51.

Further, in the extruder pressure control section 24, the PID control is performed based on the screen backwash signal or the replacement signal from the first screen changer control section 21 and the detected value of the resin pressure fluctuation of the second pressure gauge 9B. Thus, the rotation speed of the screw driving device 3 of the extruder 1 is controlled, and the discharge amount of resin is controlled. At the same time, the feeder control unit 27 also adjusts the feed rate (amount) of the feed by the feed feeder 2. Further, the gear pump pressure control unit 54 performs the first PID control on the basis of the screen backwash signal or the replacement signal from the second screen changer control unit 53 and the detected value of the resin pressure fluctuation of the fourth pressure gauge 9D. The rotation speed of the gear pump 6 is controlled. Furthermore, in the molding pressure control unit 55,
The rotation speed of the second gear pump 52 is controlled based on the resin pressure at the outlet of the second gear pump 52 detected by the fifth pressure gauge 9E, and the resin whose pressure is stabilized by this is supplied to the molding die 4. .

According to the above configuration, even if dust, foreign matter, deteriorated substances, and impurities collect on the screens 35Aa to 35Bb of the first screen replacement unit 5 and the second screen replacement unit 51, the mesh becomes finer in order. In the 2 screen replacement units 5 and 51, if the screen backwashing interval is set to an appropriate frequency, the pressure rises at the time of screen backwashing and pressure fluctuations occurring during screen replacement (set values of backwashing and resin pressure for replacement) are compared Since it is relatively small, the gear pump 6, at the outlet of the first and second screen exchange units 5, 51
52 is arranged, and the screw driving device 3 of the extruder 1 and the first unit are controlled by the extruder pressure control unit 24 and the gear pump pressure control unit 54.
By controlling the rotation speed of the gear pump 6, even if the resin pressure changes significantly and frequently due to screen backwashing and replacement, it is possible to suppress and stabilize the pressure fluctuation, and further control the molding pressure. By controlling the rotation speed of the second gear pump 52 by the portion 55, the resin can be supplied to the molding die 4 at a stable pressure.

Therefore, by arranging the gear pumps 6 and 52 corresponding to the screen exchange units 5 and 51, in the case of 100% recycled raw materials or medium and low viscosity resin raw materials containing more than 50% impurities and dust, there are two stages. Impurities can be effectively removed by the screen replacement units 5 and 51 arranged at the same time, and fluctuations in the resin pressure at the time of backwashing and replacement of the screen can be effectively suppressed, enabling continuous extrusion molding. The quality and shape and dimensions can be stabilized, and long-term continuous operation becomes possible.

In place of the screen replacement units 5, 7A, 7B, 51 in the above-mentioned respective embodiments, a breaker plate unit having a filter function is continuously rotated or a band-shaped metal mesh is wound. It may be of a type in which the surface of the breaker plate is continuously moved.

[0046]

As described above, according to the first aspect of the invention, the screen exchange unit having a plurality of stages arranged at the inlet and the unit group can effectively remove dust, foreign matters, deteriorated substances and impurities contained in the resin raw material. Can be captured as a target.
In addition, fluctuations in resin pressure that occur each time the screen is backwashed or replaced can be effectively suppressed by the multiple-stage gear pump and the extruder pressure control unit and the gear pump control unit that control the rotation speed of the extruder and gear pump. it can.
Therefore, even if the recycled material contains a lot of dust, foreign matters, deteriorated substances, and impurities, the dust, foreign substances, deteriorated substances, and impurities are effectively removed, and the resin is supplied to the molding die at a stable resin pressure. Therefore, the quality of the molded product and the accuracy of the shape and dimension are high, and stable operation for a long period of time becomes possible.

Further, according to the second aspect of the invention, the large fluctuation of the resin pressure caused by the backwashing or replacement of the unit group can be effectively suppressed by the rear gear pump pressure control section. The resin can be supplied to the molding die without controlling the rotation of the gear pump, which enables stable continuous operation for a longer period of time.

According to the third aspect of the invention, the screen exchange units are arranged in a plurality of stages in the resin path, and
Since a gear pump is arranged at the entrance of each screen exchange unit, the screen exchange units arranged in multiple stages allow dust, foreign matter, and deteriorated substances contained in the resin material to
The extruder pressure control unit that can effectively capture impurities and controls the screw rotation speed of the extruder, the gear pump control unit that controls the rotation speed of the gear pump, and the molding that controls the rotation speed of the last-stage gear pump. With the pressure control unit,
It is possible to effectively suppress the fluctuation of the resin pressure that occurs each time the screen is backwashed or replaced. Therefore, even if the recycled material contains a lot of dust, foreign matters, deteriorated substances, and impurities, the dust, foreign substances, deteriorated substances, and impurities are effectively removed, and the resin is supplied to the molding die at a stable resin pressure. Therefore, the quality of the molded product and the accuracy of the shape and dimension are high, and stable operation for a long period of time becomes possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an extrusion molding equipment according to the present invention.

FIG. 2 is a configuration diagram showing a screen exchange unit of the extrusion molding equipment.

FIG. 3 is a configuration diagram showing a backwash state of a screen of the screen exchange unit.

FIG. 4 is a configuration diagram showing a backwash state of another screen of the screen replacement unit.

FIG. 5 is a configuration diagram showing a second embodiment of the extrusion molding equipment according to the present invention.

[Explanation of symbols]

1 extruder 2 Raw material supply feeder 3 screw drive 4 die 5 1st screen replacement unit 6 1st gear pump 7 unit group 7A 2nd screen replacement unit 7B 3rd screen replacement unit 8 gear pump group 8A 2nd gear pump 8B 3rd gear pump 9A-9F 1st-6th pressure gauge 21 1st screen changer controller 22 Second screen changer controller 23 3rd screen changer controller 24 Extruder pressure controller 25 1st gear pump pressure controller 26 Second Gear Pump Pressure Control Section 27 Feeder controller 50 Extrusion control device 51 2nd screen replacement unit 52 Second gear pump 53 Second screen changer control unit 54 Gear pump pressure controller 55 Molding pressure controller

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Sakuhiro Sakane             1-89 South Kohoku, Suminoe-ku, Osaka-shi, Osaka             Issue Hitachi Shipbuilding Co., Ltd. F term (reference) 4F207 AA50 AP03 AR02 AR03 AR09                       AR11 KA01 KA17 KL38 KL94                       KM05 KM14 KM15

Claims (3)

[Claims] 1. A resin passage extending from an extruder to a molding die,
An extrusion molding facility in which a screen exchange unit with a backwash function and / or an exchange function is arranged in a plurality of stages, wherein an inlet screen exchange unit and an inlet gear pump are sequentially provided in a resin passage at the outlet of the extruder, On the inlet side of the resin passage from the gear pump to the molding die, a group of units with multiple screen exchange units arranged in series is arranged, and on the outlet side, a group of gear pumps with multiple gear pumps arranged in series is arranged. A screen changer controller for outputting a backwash command or a replacement command for the screen is provided to the screen replacement unit based on the resin pressure at the inlet of the replacement unit, and the screw of the extruder is based on the resin pressure at the outlet of the inlet screen replacement unit. An extruder pressure control unit for controlling the rotation speed is provided, and the unit Based on the resin pressure of the group of the outlet, extrusion equipment, characterized in that a pre-stage gear pump pressure control unit for controlling the rotational speed of the inlet gear pump. 2. A gear pump other than the last gear pump of the gear pump group, wherein the last gear pump of the gear pump group is configured to be driven at a constant rotation speed.
The extrusion molding equipment according to claim 1, further comprising a rear gear pump pressure control unit that controls a rotation speed based on a resin pressure at the outlet. 3. An extrusion molding facility in which a screen replacement unit with a backwash function and / or a replacement function is arranged in a plurality of stages in a resin passage extending from a screw type extruder to a molding die. , The screen replacement units are arranged in a plurality of stages, a gear pump is interposed at the outlet of each screen replacement unit, and a screen backwash command or replacement command is issued to the screen replacement unit based on the resin pressure at the inlet of each screen replacement unit. An output screen changer control unit is provided, and an extruder pressure control unit that controls the screw rotation speed of the extruder based on the resin pressure at the outlet of the frontmost screen exchange unit is provided. A molding pressure control unit for controlling the rotation speed of the gear pump at the last stage based on And a gear pump pressure control unit for controlling the rotation speed of a gear pump arranged at the inlet of the screen exchange unit based on the resin pressure at the outlet of the screen exchange unit other than the first and last stages. Extrusion molding equipment.