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Increasing the Accuracy of the Formation of a Given Thickness of Polyethylene Pipes for the Production in Extrusion Lines
18th IFAC Conference on Technology, Culture and International 18th IFAC Conference on Technology, Culture and International Stability 18th IFAC Conference on Technology, Culture and International 18th IFAC Conference Sept on Technology, Culture and International Stability Baku, Azerbaidschan, 13-15, 2018 Available online at www.sciencedirect.com Stability Stability Baku, Azerbaidschan, Sept 13-15, 2018Culture and International 18th IFAC Conference on Technology, Baku, Azerbaidschan, Sept 13-15, 2018 Baku, Azerbaidschan, Sept 13-15, 2018 Stability Baku, Azerbaidschan, Sept 13-15, 2018
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PapersOnLine 51-30 (2018) 396–399 INCREASING THEIFAC ACCURACY OF THE FORMATION OF A GIVEN INCREASING THE ACCURACY OF THE FORMATION OF A GIVEN INCREASING THE ACCURACY OF THE FORMATION OF A GIVEN THICKNESS OFTHE POLYETHYLENE PIPES FOR THE PRODUCTION IN INCREASING ACCURACY OF THE FORMATION OF A GIVEN THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN INCREASING THE ACCURACY OF THE FORMATION OF A GIVEN THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN EXTRUSION LINES THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN EXTRUSION LINES THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN EXTRUSION LINES EXTRUSION LINES First R.G.EXTRUSION Mammadov. Second R.Z. Novruzova LINES First R.G. Mammadov. Second R.Z. Novruzova
First First R.G. R.G. Mammadov. Mammadov. Second Second R.Z. R.Z. Novruzova Novruzova Azerbaijan State Oil and Industry University, Azerbaijan First State R.G. Oil Mammadov. Second R.Z. Baku, Novruzova Azerbaijan and Industry University, Baku, Azerbaijan (Tel: +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan State Oil5143876, and Industry University, Baku, Azerbaijan Azerbaijan (Tel: +99455 e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel: +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel: +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel:(Tel: +994507171046, e-mail: [email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel: +994507171046, e-mail: [email protected]) (Tel: Azerbaijan State Oil and e-mail: [email protected]) University, Baku, Azerbaijan (Tel: +994507171046, +994507171046, e-mail: [email protected]) Abstract: The article (Tel: assigns the problem ofe-mail: increasing the accuracy of the formation of a given +994507171046, [email protected]) Abstract: The The article article assigns assigns the the problem problem of of increasing increasing the the accuracy of of the formation formation of of a given Abstract: thickness of polyethylene pipes for the production in extrusion lines. Constructive, algorithmic and Abstract: The article assigns the problem of increasing the accuracy accuracy of the the formation of aa given given thickness of polyethylene pipes for the production in extrusion lines. Constructive, algorithmic and thickness of polyethylene pipes for the production in extrusion lines. Constructive, algorithmic and software methods are proposed for the solution of the problem. Destabilizing factors impacting the Abstract: article assigns of increasing the accuracy of the formation of a given thickness ofThe polyethylene pipesthe forproblem the solution production in extrusion lines. Constructive, algorithmic and software methods are proposed for the of the problem. Destabilizing factors impacting the accuracy of forming a given pipe wall thickness have been identified, and methods for eliminating the software methods are proposed for the solution of the problem. Destabilizing factors impacting thickness offorming polyethylene pipes for thethickness production inbeen extrusion lines. Constructive, algorithmic software methods area given proposed for the solution of the problem. Destabilizing factors impacting and the accuracy of pipe wall have identified, and methods for eliminating the main factors impacting the emergence of errors inhave the production of plastic pipes arefor proposed. accuracy of forming pipe wall thickness been identified, and eliminating software methods areaa given proposed theof solution of problem. impacting the accuracy of forming given pipefor wall thickness been identified, and methods methods eliminating the main factors factors impacting the emergence emergence errors in inhave thethe production ofDestabilizing plastic pipes factors arefor proposed. main impacting the of errors the production of plastic pipes are proposed. accuracy of forming a given pipe wall thickness have been identified, and methods for eliminating the main factors impacting the emergence of errors in the production of plastic pipes are proposed. © 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Key impacting words: extrusion, plastic pipes, wall thickness, batcher, error pipes are proposed. main factors the emergence of errors in the production of plastic Key words: words: extrusion, extrusion, plastic plastic pipes, pipes, wall wall thickness, thickness, batcher, batcher, error error Key Key words: extrusion, plastic pipes, wall thickness, batcher, error Key words: extrusion, plastic pipes, wall thickness, batcher, error The following denotations have been accepted in 1. INTRODUCTION 1. INTRODUCTION The following denotations have in fig.1: 1- bunker; 2- extruder, 3 -vacuum bath,accepted 4- cooling 1. INTRODUCTION The following denotations have been been accepted in 1. INTRODUCTION The following denotations have been accepted in fig.1: 1bunker; 2extruder, 3 -vacuum bath, 4cooling Due to their high technical properties, convenient use bath, 5. pulling mechanism, 6. detachable mechanism with fig.1: 1bunker; 2extruder, 3 -vacuum bath, 4cooling 1. INTRODUCTION The following denotations have been in fig.1: 1- bunker; 2- extruder, 3 -vacuum bath,accepted 4- cooling Due to their high technical properties, convenient use bath, 6. mechanism with and affordable price, pipes are convenient widely useduse in planetary cuttingmechanism, unit, 7. folding table. Due to to their their highpolyethylene technical properties, properties, convenient use bath, 5. 5.1-pulling pulling mechanism, 6. 3detachable detachable mechanism with fig.1: bunker; 2- extruder, -vacuum mechanism bath, 4- cooling Due high technical bath, 5. pulling mechanism, 6. detachable with and affordable price, polyethylene pipes are widely used in planetary cutting unit, 7. folding table. various of high economics. have the following line works the following ways. with and affordable affordable price, polyethylene pipes are convenient widely useduse in planetary cutting unit,according 7. folding folding table. Duefields to their technicalThey properties, bath, The 5. pulling mechanism, 6. detachable mechanism and price, polyethylene pipes are widely used in planetary cutting unit, 7. table. various fields of economics. They have the following The line works according the following ways. The raw material is poured into the bunker various fields of economics. They have the following line works according the following ways. on an advantages over steel pipes: durability, ease of mounting, and affordable price, polyethylene pipes are widely used in various fields ofsteel economics. They have the following planetary cutting unit,according 7. is folding table. The line works the following ways. advantages over pipes: durability, ease of mounting, The raw material poured into the bunker on an extruder. The strain gauge of gravimetric batcher advantages over steel pipes: durability, ease of mounting, The raw material is poured into the bunker on for an corrosion resistant, hygiene. However, polyethylene pipes various fields economics. They have following works according thegravimetric following ways. advantages overofsteel pipes: However, durability, easethe of mounting, The line raw material is poured into the bunker on an corrosion resistant, hygiene. polyethylene pipes extruder. The strain gauge of batcher for measuring the weight of the raw material is attached to the corrosion resistant, hygiene. However, polyethylene pipes extruder. The strain gauge of gravimetric batcher for have several disadvantages over steel pipes. One of these advantages over steel pipes:over durability, ease One of mounting, The raw material is poured into the attached bunker on the an corrosion resistant, hygiene. However, polyethylene pipes extruder. The strain ofgauge of material gravimetric batcher for have several disadvantages steel pipes. of these measuring the the batcher, is connected toofthe chassisis the line.to have several several disadvantages over steel pipes. pipes. One of pipes these measuring the weight weight of the raw raw material isofattached attached toThe the disadvantages is inadequate strength. The One strength of corrosion resistant, hygiene.over However, polyethylene extruder.which The strain gauge gravimetric batcher for have disadvantages steel of these measuring the weight of the raw material is to the disadvantages is inadequate strength. The strength of batcher, which is connected to the chassis of the line. The extruder consists a screw a cylinder and for disadvantages is inadequate inadequate strength. The strength of batcher, which which is of connected to the the chassisisof of theheaters line.toThe The polyethylene pipes is impacted by the accuracy the have several disadvantages over steel pipes. One ofof these measuring the weight of the with raw material attached the disadvantages is strength. The strength of batcher, is connected to chassis the line. polyethylene pipes is impacted by the accuracy of the extruder consists of aathe screw with aa form. cylinder and heaters for formation of wall thickness of the pipes of which due to shaping the pipe in necessary Being heated and polyethylene pipes is impacted by the accuracy of the extruder consists of screw with cylinder and heaters for disadvantages is inadequate strength. strength of batcher, which is of connected to thea form. chassis of theheated line. The polyethylene pipes is impacted bypipes the The accuracy of the extruder the consists athe screw with cylinder and heaters for formation of wall thickness of the of which due to shaping pipe in necessary Being and the action, of destabilizing factors isaccuracy for by means of the auger the raw material moves in the cavity formation ofvarious wall thickness of the the pipes ofinsufficient which due due to shaping the pipe in the necessary form. Being heated and polyethylene pipes is impacted by the of the formation wall thickness of pipes of which to extruder consists of screw with a form. cylinder andinheated heaters for shaping the pipe in athe necessary Being and the action, various destabilizing factors is insufficient for by means of the the raw moves the cavity today. of the cylinder. Being in the material decomposed form, raw the action, ofvarious various destabilizing factors isofinsufficient insufficient for by means of pipe the auger auger the raw material moves inheated thethe cavity formation wall thickness of the pipesis which duefor to shaping the in thethe necessary form.moves Being and the action, destabilizing factors by means of the auger raw material in the cavity today. of the cylinder. Being in the decomposed form, the raw material enters forming head, where it takes the form today. of means the cylinder. cylinder. Being in raw the decomposed form, the raw Owingvarious to the fact that the existing systemsfor of the action, destabilizing factors control is insufficient by of thethe auger the material moves in the cavity today. of the Being in the decomposed form, the raw Owing to the fact that the existing control systems of material enters the forming head, where it takes the form of a hollow tube. Being pressed by vacuum to the walls of Owing to the fact that the existing control systems of material enters the forming head, where it takes the form extrusion lines for the production of polyethylene pipes do today.Owing of athe cylinder. Being in the decomposed form, theform raw to for the the factproduction that the existing control systems of material enters the forming head, where it takes the extrusion lines of polyethylene pipes do of hollow tube. Being pressed by vacuum to the walls of of the calibrator, the molten material takes the form of a pipe extrusion lines for the production of polyethylene pipes do of a hollow tube. Being pressed by vacuum to the walls of not allow to achieve a certain accuracy in the formation Owing to for the the fact that theaccuracy existing control systems of material enters theBeing forming head, where it takes the form extrusion lines production of polyethylene pipes do of acalibrator, hollow tube. pressed bytakes vacuum to theof walls of not allow to achieve a certain in the formation of the the molten material the form a pipe the with the required diameter by means of a vacuum bath and not allow to achieve a certain accuracy in the formation of the calibrator, the molten material takes the form of a pipe aextrusion given pipe thickness, some measures for improving lines for thea production of polyethylene pipes the do of acalibrator, hollow tube. Being bytakes vacuum to theof walls of not allowpipe to achieve certain accuracy infortheimproving formation of the thediameter moltenpressed material the form a pipe aa given thickness, some measures the by of vacuum bath and accuracy of a given thickness ofimproving polyethylene awith calibrator. given pipe thickness, some measures forthe improving the with the required required diameter by means means of aaathe vacuum bath and allowpipe to formation achieve a of certain accuracy infor formationthe of anot given thickness, some measures the calibrator, thediameter molten material takes form of a pipe with the required by means of vacuum bath and accuracy of formation of a given thickness of polyethylene a calibrator. have developed. Stretching thediameter molten bymaterial, mechanism accuracy ofbeen formation ofsome given thickness ofimproving polyethylene calibrator. apipes given pipe thickness, measures forof the with the required means ofpulling a vacuum bath and accuracy of formation of aa given thickness polyethylene aa calibrator. pipes have been developed. Stretching the molten material, pulling mechanism provides the formation of a given pipe wall thickness. pipes have been developed. Stretching the molten material, pulling mechanism accuracy formation of a given thickness of polyethylene aprovides calibrator. pipes haveofbeen developed. Stretching the molten material, pulling mechanism the formation of a given pipe wall thickness. 2. been SETTLEMENT THE PROBLEM. After the the length of molten the pipe m, wall the mechanism pipe is cut provides the formation of material, given 12 pipe wall thickness. pipes have developed. OF Stretching the pulling provides formation of aareaches given pipe thickness. 2. SETTLEMENT OF THE PROBLEM. After the length of the pipe reaches 12 m, the pipe is cut 2. SETTLEMENT OF THE PROBLEM. After the length of the pipe reaches 12 m, the pipe is cut using a planetary cutting unit and moves through the roller provides the formation of areaches given pipe wall thickness. 2. SETTLEMENT OF THE PROBLEM. After the length of the pipe 12 m, the pipe is cut using a planetary cutting unit and moves through the roller Currently, the following structure of extrusion pipe using a planetary cutting unit and moves through the roller table until the pipe is removed for further transportation. 2. SETTLEMENT OFstructure THE PROBLEM. After length of the pipe 12 m, the pipe cut using athe planetary cutting unitreaches andfor moves through the is roller the following of pipe table until the pipe is removed further transportation. lines Currently, are used for production of plastic pipes from Currently, the the following structure of extrusion extrusion pipe table until until the pipe is removed removed for further transportation. During the entire process, theand pipe isfurther forced to the towing using a planetary cutting unit moves through the roller Currently, the following structure of extrusion pipe table the pipe is for transportation. lines are for the production of pipes During the entire process, the pipe is forced to the towing polyethylene. in thestructure formation plastic pipe lines Currently, are used usedThe for the production of plastic plastic pipes from from Duringuntil the entire process, the pipe isfurther forced to the the towing towing vehicle to be cooled a the water bath. On cooling plastic theerror following of of extrusion pipe table the pipe isin removed for transportation. lines are used for the production of plastic pipes from During the entire process, pipe is forced to polyethylene. The error in the formation of plastic pipe vehicle to be cooled in a water bath. On cooling plastic thickness forms 1% during the use of these lines (fig.1). polyethylene. The error in the formation of plastic pipe vehicle to be cooled in a water bath. On cooling plastic materials have a shrinkage, which is usually 1-2%. lines are forms usedThe for the production ofthese plastic pipes from During entire process, pipe is forced to the towing polyethylene. error inthe theuse formation of plastic pipe vehicle the to have be cooled in a the water bath. On cooling plastic thickness 1% during of lines (fig.1). materials a shrinkage, which is usually 1-2%. Therefore, the thickness of the pipe wall is measured only thickness forms 1% during the use of these lines (fig.1). materials have a shrinkage, which is usually 1-2%. polyethylene. theuse formation of plastic vehicle to have be cooled in of a water bath. On cooling plastic thickness formsThe 1%error duringinthe of these lines (fig.1).pipe materials a shrinkage, which isis usually 1-2%. Therefore, the thickness the pipe wall measured only after it has cooled completely by means of measuring Therefore, the thickness of the pipe wall is measured only thickness forms 1% during the use of these lines (fig.1). materials have a shrinkage, which isis usually 1-2%. Therefore, thecooled thickness of the pipe wall measured only after it has completely by means of measuring instruments (calipers, roulettes, and so on). after it has cooled completely by means of measuring Therefore, thickness of the pipe wall is measured only after it hasthe cooled completely byso means of measuring instruments (calipers, roulettes, and on). 1 instruments (calipers, roulettes, and someans on). Extrusion lines are equipped with automatic control 11 after it has cooled completely by of measuring instruments (calipers, roulettes, and so on). Extrusion lines are equipped with automatic control Extrusion lines are equipped with automatic control 1 system for (calipers, thelines production of and plastic pipes. It includes instruments roulettes, so on). Extrusion are equipped with automatic control system for the production of plastic pipes. It includes system for the production of plastic pipes. It includes 1 microprocessor, remote control keyboard, as well as Extrusion are equipped with automatic control system for thelines production of plastic pipes. It includes microprocessor, remote control keyboard, as well as microprocessor, remote control keyboard, as well as 7 memory block in which several technological parameters 3 4 5 6 system for the inproduction of plastic pipes. asIt includes microprocessor, remote control keyboard, well as memory block which several technological parameters 77 33 44 55 66 memory block in which several technological parameters are located. This gives an opportunity to produce wares microprocessor, control keyboard, asparameters well as memory block in remote which an several technological 2 The structure are located. This gives opportunity to produce wares 3 5 6 lines. 7 Fig.1. of4 pipe extrusion with various characters in the same line. Forparameters this,wares it is are located. located. This gives an opportunity to produce produce wares 22 The structure memory block in gives which an several technological are This opportunity to 7 Fig.1. of pipe extrusion lines. 3 4 5 6 with various characters in the same line. For this, it is sufficient toThis introduce theopportunity software intowares 2 The Fig.1. The structure structure of of pipe pipe extrusion extrusion lines. lines. withlocated. various characters in theexisting same line. line. For this, this, itthe is are gives an to produce Fig.1. with various characters in the same For it is sufficient to introduce the existing software into the 2 memory block. sufficient to introduce the existing software into the Fig.1. The structure of pipe extrusion lines. with various same line. For this, is sufficient to characters introduce in thetheexisting software into itthe memory block. memory block. block. sufficient to introduce the existing software into the memory Copyright © 2018, 2018 IFAC 396Hosting 2405-8963 © IFAC (International Federation of Automatic Control) by Elsevier Ltd. All rights reserved. Copyright © 2018 IFAC 396 memory block. Peer review©under of International Federation of Automatic Copyright 2018 responsibility IFAC 396Control. Copyright © 2018 IFAC 396 10.1016/j.ifacol.2018.11.338 Copyright © 2018 IFAC 396
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Automatic control system consists of 2 parts, between which the connection is carried out by COM ports: operator panel and software logical unit (SLU) (fig.2).
Operator panel COM port
Software logical unit
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procedure is controlled in an automatic mode. The whole process occurs synchronously in time. While the program is being written, operator errors are taken into account with the possibility of eliminating emergencies. When the operator transmits the data of the diameter and the thickness of pipe wall, by means of the operator's data and the data of the strain gauge, the PLC calculates the actual weight delivered via the set weight and, in this coincidence, it instructs the motor driver to pull the pipe at the rate at which the weight condition is observed as 1 running meter. The programmer writes conditions, formulas, as well as attaches all these data to the time. The detailed analysis of the whole process shows that, the formation of the thickness of the plastic pipes walls with an error in the redistribution of in existing extrusion lines is achieved only by the cost of over-expenditure of raw materials or by a 6-meter length of pipe: 𝜕𝜕𝜕𝜕 𝜕𝜕𝜕𝜕 𝜕𝜕𝜕𝜕 (1) 𝜎𝜎 = 𝑓𝑓(𝜐𝜐, ∆𝜌𝜌, ∆𝑇𝑇𝑟𝑟 , 𝑟𝑟 , ∆𝑇𝑇𝑐𝑐 , 𝑐𝑐 , 𝑑𝑑 , ∆𝑚𝑚)
Sensors Driver
Fig.2. Automatic control system of the formation of a given thickness of polyethylene pipes for the production in extrusion lines This unit is operated by the control software which in its turn consists of 2 parts. The first part software is written in the operator panel and the second one in PLC. The first written part is divided into several parts. They include the pages described on the operator panel for visualization and input operator. The second part software is directly recorded in PLC. Language program LAD (Ladder Diagram) is used for the simplification of the written program. The program recorded in PLC operates the drivers on the base of the date from the sensors. All this process is synchronized in real-time mode. See the sample. The used units are GMT operator panel, PLC company GMT. Software GMT soft version 2.3 for operator panel and for PLC GMT version 5.0.1.4. The connection between the units is carried out via COM port PPI cable. In its turn PLC has its input extensions – input and connection between the main parts of the device is carried out via screened wires for noise immunity system. As input device for PLC, strain gauge, tachogenerator, sensors are used. But relay assembly is taken for output driver. When the machine is turned on for the first time, the monitor opens. After the selection of the operator language, the second window opens. It includes the areas for entering temperature conditions, real temperature visualization, screw speed, the speed of pulling mechanism, motor current, and so on. The operator first enters the required temperature, the data prescribed by the raw material certificate, then the line is considered to be ready for the operation after the cylinder has been heated up. If the temperatures haven’t reached the set values, the software doesn’t give an opportunity to turn on the auger motors. This is an emergency situation for the screw. After heating up, the auger is turned on and the auger turns are set. On the main window the operator has two options of work. The first option is manual; the second one is automatic (weighing batcher). After the operator has tested the line manually, he presses the gravimetric control button and enters the diameter, the thickness of the pipe wall. Then the program recorded on the monitor transmits the data entered by the operator to the PLC where the input information is processed, the weight is calculated per 1 pt. of the meter and the PLC gives the driver the pulling speed which should be pulled via the pulling mechanism. All this
𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
where: 𝜐𝜐 is the extrusion line vibration, ∆𝜌𝜌 is the absolute 𝜕𝜕𝜕𝜕 change of the raw materials density, ∆𝑇𝑇𝑟𝑟 & 𝑟𝑟 relatively is 𝜕𝜕𝜕𝜕 instability in the changes of heating rate of raw materials, 𝜕𝜕𝜕𝜕 ∆𝑇𝑇𝑐𝑐 & 𝑐𝑐 relatively is instability in the changes of cooling 𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
rate of raw materials, 𝑑𝑑 is instability of prime mover rate 𝜕𝜕𝜕𝜕 and ∆𝑚𝑚 is instability of raw materials mass. Anyway, all these instabilities influence on the accuracy of the formation of the given thickness of the pipes. The ways for eliminating these disadvantages have been proposed to increase the accuracy of the formation of the given thickness of the pipes. Since the strain gauge is attached to a batcher that is connected to the line chassis in the gravimetric batcher for measuring the weight, then vibrations occur which lead to the additional errors in the formation of the thickness of the pipes walls. In this case, an additional batcher not attached to the extrusion lines mechanically is proposed to be used. Raw materials are delivered into an additional bunker, and from there they enter the main bunker. In this case an additional bunker vibration doesn’t take place. Strain gauges for the gravimetric weighing batcher in existing lines are installed under the extruder bunker or suspended above the batcher, which is unacceptable in terms of the vibration interference impacting the strain gauge. Strain gauges are proposed to be installed in the tanker where raw materials will be transported into the bunker. For the solution of the problem with the instability of raw materials density, the software has been changed, additional parameters have been introduced (the raw materials density of the origin certificate for raw materials). Theoretical mass of one running meter of pipe is determined as follows: 𝜋𝜋∙(𝑑𝑑−𝑠𝑠)∙𝑠𝑠∙𝜌𝜌 , (2) 𝑚𝑚 = 1000
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where m is the theoretical mass of one running meter of pipe in kg, π=3,14 (constant value), d is the outer diameter of pipe in mm, s is the thickness of pipe walls in mm, p is the density of the material in sm. For the stability of the length and thickness of the pipe wall with the possible damage, it is suggested to control the weight of the raw material for the production of per 10 cm of the pipe, instead of controlling the weight of the raw materials for producing one meter of the pipe. For this purpose, a gravimetric batcher with corresponding strain gauges and a bridge measuring circuit has been installed and corresponding changes have been made in the program. The proposed method is to automate production forming a standard wall thickness of the pipe by controlling the weight of its running meter. Such a sample is given: Ф110РN10 S=6,6 м=2,190 kg. It is seen from the sample that 2.19 kg of raw material is required to form a pipe wall thickness equal to 6.6 mm with its length of 1 meter. For the implementation of this method, a weight sensor and a control system of the pulling mechanism and a tachometer for viewing and controlling the speed of the pipe moving on the line are used. It should be noted that on plastic pipes depending on the diameter, the pipe should have a certain wall thickness with a possible dispersion in the positive direction. Thus, for a pipe Ф110 PN10, the wall thickness should be 6.6mm + 0.8mm, i.e. 6,6 mm + 0, mm. Gravimeter INOEX gives the results within this thickness, namely 7.2 mm which leads to over expenditure of raw materials. It originates according to the following reasons. When the thickness of the pipe walls approached the record of 6.6 mm, the operator of the lines had to reduce the weight of incoming raw materials in the operator panel via a dispenser in order to approach the lower limit of the wall thickness and, thereby, to reduce the over-expenditure of raw materials. This required the operators of high-skill lines and led to the risk of yielding wall thickness beyond the permissible limits. For reducing the length of the pipe with a possible damage from 6 m to 10 cm, it is suggested to control the weight of the raw material (0.219 kg) for producing each 10 cm of the pipe instead of controlling the weight of the raw material (2.190 kg) for producing one running meter of the pipe. The raw material has a solid form of granules fraction of4-5 mm and is delivered in bags of 25 kg. The raw material is attached by a certificate of conformity, in which its technical and chemical data are indicated. The raw material certificate indicates the percentage of moisture. Raw material is poured into the batcher, which is attached to the extruder. The extruder consists of a cylinder, in which a worm rotates. The cylinder itself is heated by heaters placed on the cylinder. Heating zone is 6-8. The heating temperature is indicated in the certificate and ranges from 1900 to 2100. Moving in the cavity of the cylinder, being melted the raw material moves to the head.
1. At the end of the head, it melts completely and takes the form of a soft monolithic mass. While leaving the head, it naturally loses some mass. The mass differs from its original state. It takes place is due to the evaporation, after heating. From the experiments made at plant Croplast, Baku, the data shown in the table has been obtained. Tabl.1. Dependence of mass loss on temperature and holding time Melting temperature Time limit Weight loss 190 15 0,028 200 15 0,031 210 15 0,032 During heating process, not only moisture but also some plastic components evaporate. Increasing to 16-21% at 2100, plastic also changes its volume from its original state at 230. After its cooling to 230, there aw materials hrinks forming 16-21%. Coming out in the form of a soft monolithic mass, raw material enters the calibrator, where it is pressed against the walls of the calibrator and takes the form of a hollow tube. It takes place is due to vacuum pumps. Moving further along the line, the pipe is cooled to 23 0 by forced water cooling. Further, the pipe is cut into segments. As it has been observed, raw materials undergo three conditions. Solid, soft heated and hard original. While its state is changing, it changes its weight ∆m and volume ∆v. Because of the loss ∆m, which forms ≈0,03%, and it loses its volume ∆v. The instability of the thermoregulatory, which unevenly heats the raw material up in the cylinder cavity contributes to the retention of raw materials and the irregular motion of the raw materials in the extruder, which in its turn influence on the rate at which the raw material mass exits out of the head. While pulling the pipe, the pulling mechanism also has its own errors. The reasons are resulted in the voltage swings, variable load and slip of the pipe from under the caterpillar of the pulling device. The table shows the results of the investigation of the prime mover behavior within 1 hour. Tabl.2. The behavior of the tractor when changing the supply voltage and load Voltage swing, B Load Slip 384 7,3 1,2 396 7,8 1,16 The following table shows the results of comparing the wall thickness during the production of the gravity control pipe of the company INOEX and the company Croplast.
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Tabl.3. The results of the proposed approaches to improve the accuracy of forming the wall thickness of polyethylene pipes The thickness of the wall INOEX Croplast 6.6 7,2 6,8 42.1 45,6 42,7 Thus, the influence of all three factors on the error in the formation of the thickness of the pipe has been eliminated partially. The proposed solutions have been implemented during the production of plastic pipes at the plant “Croplast” (Baku). 3. CONCLUSION In the presented article, more practical ways are proposed for increasing the accuracy of a given thickness of polyethylene pipes in extrusion lines. As a result of its implementation, the error reduces the formation of pipe thickness, saves raw materials, increases the productivity and reduces financial costs (for electricity and labor force). REFERENCES Bronshtein I.N., Semendyayev K.A. (1981). A handbook on mathematics for engineers and students of technical colleges. - Moscow: Publisher “Science”. Extruzionnie linii dlya proizbodstva trub http://newpostavka.ru/linii_po_proizvodstvu/proizvodstvo _trub Mammadov R.G., Novruzova R.Z. (2016). Improvement of the control system of polyethylene pipes in extrusion lines. – Instruments and Systens: Monitoring, Control, and Diagnostics.- № 10,pp. 46-48. Mammadov R.G., Novruzova R.Z. (2016). Control system of polyethylene pipes production in extrusion lines. “Materials of the V International scientific- practical conference “Information Control Systems and Technologies”.- 22th September, Odessa.- pp.32-35. http://www.kazgp.ru/teoriya/31tehnika_i_tehnologiya_proizvodstva_polimernyih_trub.ht ml http://www.plastics.ru/pdf/journal/2014/06/Inoex.pdfBudushee- za AUREX m-line.
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PapersOnLine 51-30 (2018) 396–399 INCREASING THEIFAC ACCURACY OF THE FORMATION OF A GIVEN INCREASING THE ACCURACY OF THE FORMATION OF A GIVEN INCREASING THE ACCURACY OF THE FORMATION OF A GIVEN THICKNESS OFTHE POLYETHYLENE PIPES FOR THE PRODUCTION IN INCREASING ACCURACY OF THE FORMATION OF A GIVEN THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN INCREASING THE ACCURACY OF THE FORMATION OF A GIVEN THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN EXTRUSION LINES THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN EXTRUSION LINES THICKNESS OF POLYETHYLENE PIPES FOR THE PRODUCTION IN EXTRUSION LINES EXTRUSION LINES First R.G.EXTRUSION Mammadov. Second R.Z. Novruzova LINES First R.G. Mammadov. Second R.Z. Novruzova
First First R.G. R.G. Mammadov. Mammadov. Second Second R.Z. R.Z. Novruzova Novruzova Azerbaijan State Oil and Industry University, Azerbaijan First State R.G. Oil Mammadov. Second R.Z. Baku, Novruzova Azerbaijan and Industry University, Baku, Azerbaijan (Tel: +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan State Oil5143876, and Industry University, Baku, Azerbaijan Azerbaijan (Tel: +99455 e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel: +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel: +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel:(Tel: +994507171046, e-mail: [email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan +99455 5143876, e-mail:[email protected]) Azerbaijan State Oil and Industry University, Baku, Azerbaijan (Tel: +994507171046, e-mail: [email protected]) (Tel: Azerbaijan State Oil and e-mail: [email protected]) University, Baku, Azerbaijan (Tel: +994507171046, +994507171046, e-mail: [email protected]) Abstract: The article (Tel: assigns the problem ofe-mail: increasing the accuracy of the formation of a given +994507171046, [email protected]) Abstract: The The article article assigns assigns the the problem problem of of increasing increasing the the accuracy of of the formation formation of of a given Abstract: thickness of polyethylene pipes for the production in extrusion lines. Constructive, algorithmic and Abstract: The article assigns the problem of increasing the accuracy accuracy of the the formation of aa given given thickness of polyethylene pipes for the production in extrusion lines. Constructive, algorithmic and thickness of polyethylene pipes for the production in extrusion lines. Constructive, algorithmic and software methods are proposed for the solution of the problem. Destabilizing factors impacting the Abstract: article assigns of increasing the accuracy of the formation of a given thickness ofThe polyethylene pipesthe forproblem the solution production in extrusion lines. Constructive, algorithmic and software methods are proposed for the of the problem. Destabilizing factors impacting the accuracy of forming a given pipe wall thickness have been identified, and methods for eliminating the software methods are proposed for the solution of the problem. Destabilizing factors impacting thickness offorming polyethylene pipes for thethickness production inbeen extrusion lines. Constructive, algorithmic software methods area given proposed for the solution of the problem. Destabilizing factors impacting and the accuracy of pipe wall have identified, and methods for eliminating the main factors impacting the emergence of errors inhave the production of plastic pipes arefor proposed. accuracy of forming pipe wall thickness been identified, and eliminating software methods areaa given proposed theof solution of problem. impacting the accuracy of forming given pipefor wall thickness been identified, and methods methods eliminating the main factors factors impacting the emergence emergence errors in inhave thethe production ofDestabilizing plastic pipes factors arefor proposed. main impacting the of errors the production of plastic pipes are proposed. accuracy of forming a given pipe wall thickness have been identified, and methods for eliminating the main factors impacting the emergence of errors in the production of plastic pipes are proposed. © 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Key impacting words: extrusion, plastic pipes, wall thickness, batcher, error pipes are proposed. main factors the emergence of errors in the production of plastic Key words: words: extrusion, extrusion, plastic plastic pipes, pipes, wall wall thickness, thickness, batcher, batcher, error error Key Key words: extrusion, plastic pipes, wall thickness, batcher, error Key words: extrusion, plastic pipes, wall thickness, batcher, error The following denotations have been accepted in 1. INTRODUCTION 1. INTRODUCTION The following denotations have in fig.1: 1- bunker; 2- extruder, 3 -vacuum bath,accepted 4- cooling 1. INTRODUCTION The following denotations have been been accepted in 1. INTRODUCTION The following denotations have been accepted in fig.1: 1bunker; 2extruder, 3 -vacuum bath, 4cooling Due to their high technical properties, convenient use bath, 5. pulling mechanism, 6. detachable mechanism with fig.1: 1bunker; 2extruder, 3 -vacuum bath, 4cooling 1. INTRODUCTION The following denotations have been in fig.1: 1- bunker; 2- extruder, 3 -vacuum bath,accepted 4- cooling Due to their high technical properties, convenient use bath, 6. mechanism with and affordable price, pipes are convenient widely useduse in planetary cuttingmechanism, unit, 7. folding table. Due to to their their highpolyethylene technical properties, properties, convenient use bath, 5. 5.1-pulling pulling mechanism, 6. 3detachable detachable mechanism with fig.1: bunker; 2- extruder, -vacuum mechanism bath, 4- cooling Due high technical bath, 5. pulling mechanism, 6. detachable with and affordable price, polyethylene pipes are widely used in planetary cutting unit, 7. folding table. various of high economics. have the following line works the following ways. with and affordable affordable price, polyethylene pipes are convenient widely useduse in planetary cutting unit,according 7. folding folding table. Duefields to their technicalThey properties, bath, The 5. pulling mechanism, 6. detachable mechanism and price, polyethylene pipes are widely used in planetary cutting unit, 7. table. various fields of economics. They have the following The line works according the following ways. The raw material is poured into the bunker various fields of economics. They have the following line works according the following ways. on an advantages over steel pipes: durability, ease of mounting, and affordable price, polyethylene pipes are widely used in various fields ofsteel economics. They have the following planetary cutting unit,according 7. is folding table. The line works the following ways. advantages over pipes: durability, ease of mounting, The raw material poured into the bunker on an extruder. The strain gauge of gravimetric batcher advantages over steel pipes: durability, ease of mounting, The raw material is poured into the bunker on for an corrosion resistant, hygiene. However, polyethylene pipes various fields economics. They have following works according thegravimetric following ways. advantages overofsteel pipes: However, durability, easethe of mounting, The line raw material is poured into the bunker on an corrosion resistant, hygiene. polyethylene pipes extruder. The strain gauge of batcher for measuring the weight of the raw material is attached to the corrosion resistant, hygiene. However, polyethylene pipes extruder. The strain gauge of gravimetric batcher for have several disadvantages over steel pipes. One of these advantages over steel pipes:over durability, ease One of mounting, The raw material is poured into the attached bunker on the an corrosion resistant, hygiene. However, polyethylene pipes extruder. The strain ofgauge of material gravimetric batcher for have several disadvantages steel pipes. of these measuring the the batcher, is connected toofthe chassisis the line.to have several several disadvantages over steel pipes. pipes. One of pipes these measuring the weight weight of the raw raw material isofattached attached toThe the disadvantages is inadequate strength. The One strength of corrosion resistant, hygiene.over However, polyethylene extruder.which The strain gauge gravimetric batcher for have disadvantages steel of these measuring the weight of the raw material is to the disadvantages is inadequate strength. The strength of batcher, which is connected to the chassis of the line. The extruder consists a screw a cylinder and for disadvantages is inadequate inadequate strength. The strength of batcher, which which is of connected to the the chassisisof of theheaters line.toThe The polyethylene pipes is impacted by the accuracy the have several disadvantages over steel pipes. One ofof these measuring the weight of the with raw material attached the disadvantages is strength. The strength of batcher, is connected to chassis the line. polyethylene pipes is impacted by the accuracy of the extruder consists of aathe screw with aa form. cylinder and heaters for formation of wall thickness of the pipes of which due to shaping the pipe in necessary Being heated and polyethylene pipes is impacted by the accuracy of the extruder consists of screw with cylinder and heaters for disadvantages is inadequate strength. strength of batcher, which is of connected to thea form. chassis of theheated line. The polyethylene pipes is impacted bypipes the The accuracy of the extruder the consists athe screw with cylinder and heaters for formation of wall thickness of the of which due to shaping pipe in necessary Being and the action, of destabilizing factors isaccuracy for by means of the auger the raw material moves in the cavity formation ofvarious wall thickness of the the pipes ofinsufficient which due due to shaping the pipe in the necessary form. Being heated and polyethylene pipes is impacted by the of the formation wall thickness of pipes of which to extruder consists of screw with a form. cylinder andinheated heaters for shaping the pipe in athe necessary Being and the action, various destabilizing factors is insufficient for by means of the the raw moves the cavity today. of the cylinder. Being in the material decomposed form, raw the action, ofvarious various destabilizing factors isofinsufficient insufficient for by means of pipe the auger auger the raw material moves inheated thethe cavity formation wall thickness of the pipesis which duefor to shaping the in thethe necessary form.moves Being and the action, destabilizing factors by means of the auger raw material in the cavity today. of the cylinder. Being in the decomposed form, the raw material enters forming head, where it takes the form today. of means the cylinder. cylinder. Being in raw the decomposed form, the raw Owingvarious to the fact that the existing systemsfor of the action, destabilizing factors control is insufficient by of thethe auger the material moves in the cavity today. of the Being in the decomposed form, the raw Owing to the fact that the existing control systems of material enters the forming head, where it takes the form of a hollow tube. Being pressed by vacuum to the walls of Owing to the fact that the existing control systems of material enters the forming head, where it takes the form extrusion lines for the production of polyethylene pipes do today.Owing of athe cylinder. Being in the decomposed form, theform raw to for the the factproduction that the existing control systems of material enters the forming head, where it takes the extrusion lines of polyethylene pipes do of hollow tube. Being pressed by vacuum to the walls of of the calibrator, the molten material takes the form of a pipe extrusion lines for the production of polyethylene pipes do of a hollow tube. Being pressed by vacuum to the walls of not allow to achieve a certain accuracy in the formation Owing to for the the fact that theaccuracy existing control systems of material enters theBeing forming head, where it takes the form extrusion lines production of polyethylene pipes do of acalibrator, hollow tube. pressed bytakes vacuum to theof walls of not allow to achieve a certain in the formation of the the molten material the form a pipe the with the required diameter by means of a vacuum bath and not allow to achieve a certain accuracy in the formation of the calibrator, the molten material takes the form of a pipe aextrusion given pipe thickness, some measures for improving lines for thea production of polyethylene pipes the do of acalibrator, hollow tube. Being bytakes vacuum to theof walls of not allowpipe to achieve certain accuracy infortheimproving formation of the thediameter moltenpressed material the form a pipe aa given thickness, some measures the by of vacuum bath and accuracy of a given thickness ofimproving polyethylene awith calibrator. given pipe thickness, some measures forthe improving the with the required required diameter by means means of aaathe vacuum bath and allowpipe to formation achieve a of certain accuracy infor formationthe of anot given thickness, some measures the calibrator, thediameter molten material takes form of a pipe with the required by means of vacuum bath and accuracy of formation of a given thickness of polyethylene a calibrator. have developed. Stretching thediameter molten bymaterial, mechanism accuracy ofbeen formation ofsome given thickness ofimproving polyethylene calibrator. apipes given pipe thickness, measures forof the with the required means ofpulling a vacuum bath and accuracy of formation of aa given thickness polyethylene aa calibrator. pipes have been developed. Stretching the molten material, pulling mechanism provides the formation of a given pipe wall thickness. pipes have been developed. Stretching the molten material, pulling mechanism accuracy formation of a given thickness of polyethylene aprovides calibrator. pipes haveofbeen developed. Stretching the molten material, pulling mechanism the formation of a given pipe wall thickness. 2. been SETTLEMENT THE PROBLEM. After the the length of molten the pipe m, wall the mechanism pipe is cut provides the formation of material, given 12 pipe wall thickness. pipes have developed. OF Stretching the pulling provides formation of aareaches given pipe thickness. 2. SETTLEMENT OF THE PROBLEM. After the length of the pipe reaches 12 m, the pipe is cut 2. SETTLEMENT OF THE PROBLEM. After the length of the pipe reaches 12 m, the pipe is cut using a planetary cutting unit and moves through the roller provides the formation of areaches given pipe wall thickness. 2. SETTLEMENT OF THE PROBLEM. After the length of the pipe 12 m, the pipe is cut using a planetary cutting unit and moves through the roller Currently, the following structure of extrusion pipe using a planetary cutting unit and moves through the roller table until the pipe is removed for further transportation. 2. SETTLEMENT OFstructure THE PROBLEM. After length of the pipe 12 m, the pipe cut using athe planetary cutting unitreaches andfor moves through the is roller the following of pipe table until the pipe is removed further transportation. lines Currently, are used for production of plastic pipes from Currently, the the following structure of extrusion extrusion pipe table until until the pipe is removed removed for further transportation. During the entire process, theand pipe isfurther forced to the towing using a planetary cutting unit moves through the roller Currently, the following structure of extrusion pipe table the pipe is for transportation. lines are for the production of pipes During the entire process, the pipe is forced to the towing polyethylene. in thestructure formation plastic pipe lines Currently, are used usedThe for the production of plastic plastic pipes from from Duringuntil the entire process, the pipe isfurther forced to the the towing towing vehicle to be cooled a the water bath. On cooling plastic theerror following of of extrusion pipe table the pipe isin removed for transportation. lines are used for the production of plastic pipes from During the entire process, pipe is forced to polyethylene. The error in the formation of plastic pipe vehicle to be cooled in a water bath. On cooling plastic thickness forms 1% during the use of these lines (fig.1). polyethylene. The error in the formation of plastic pipe vehicle to be cooled in a water bath. On cooling plastic materials have a shrinkage, which is usually 1-2%. lines are forms usedThe for the production ofthese plastic pipes from During entire process, pipe is forced to the towing polyethylene. error inthe theuse formation of plastic pipe vehicle the to have be cooled in a the water bath. On cooling plastic thickness 1% during of lines (fig.1). materials a shrinkage, which is usually 1-2%. Therefore, the thickness of the pipe wall is measured only thickness forms 1% during the use of these lines (fig.1). materials have a shrinkage, which is usually 1-2%. polyethylene. theuse formation of plastic vehicle to have be cooled in of a water bath. On cooling plastic thickness formsThe 1%error duringinthe of these lines (fig.1).pipe materials a shrinkage, which isis usually 1-2%. Therefore, the thickness the pipe wall measured only after it has cooled completely by means of measuring Therefore, the thickness of the pipe wall is measured only thickness forms 1% during the use of these lines (fig.1). materials have a shrinkage, which isis usually 1-2%. Therefore, thecooled thickness of the pipe wall measured only after it has completely by means of measuring instruments (calipers, roulettes, and so on). after it has cooled completely by means of measuring Therefore, thickness of the pipe wall is measured only after it hasthe cooled completely byso means of measuring instruments (calipers, roulettes, and on). 1 instruments (calipers, roulettes, and someans on). Extrusion lines are equipped with automatic control 11 after it has cooled completely by of measuring instruments (calipers, roulettes, and so on). Extrusion lines are equipped with automatic control Extrusion lines are equipped with automatic control 1 system for (calipers, thelines production of and plastic pipes. It includes instruments roulettes, so on). Extrusion are equipped with automatic control system for the production of plastic pipes. It includes system for the production of plastic pipes. It includes 1 microprocessor, remote control keyboard, as well as Extrusion are equipped with automatic control system for thelines production of plastic pipes. It includes microprocessor, remote control keyboard, as well as microprocessor, remote control keyboard, as well as 7 memory block in which several technological parameters 3 4 5 6 system for the inproduction of plastic pipes. asIt includes microprocessor, remote control keyboard, well as memory block which several technological parameters 77 33 44 55 66 memory block in which several technological parameters are located. This gives an opportunity to produce wares microprocessor, control keyboard, asparameters well as memory block in remote which an several technological 2 The structure are located. This gives opportunity to produce wares 3 5 6 lines. 7 Fig.1. of4 pipe extrusion with various characters in the same line. Forparameters this,wares it is are located. located. This gives an opportunity to produce produce wares 22 The structure memory block in gives which an several technological are This opportunity to 7 Fig.1. of pipe extrusion lines. 3 4 5 6 with various characters in the same line. For this, it is sufficient toThis introduce theopportunity software intowares 2 The Fig.1. The structure structure of of pipe pipe extrusion extrusion lines. lines. withlocated. various characters in theexisting same line. line. For this, this, itthe is are gives an to produce Fig.1. with various characters in the same For it is sufficient to introduce the existing software into the 2 memory block. sufficient to introduce the existing software into the Fig.1. The structure of pipe extrusion lines. with various same line. For this, is sufficient to characters introduce in thetheexisting software into itthe memory block. memory block. block. sufficient to introduce the existing software into the memory Copyright © 2018, 2018 IFAC 396Hosting 2405-8963 © IFAC (International Federation of Automatic Control) by Elsevier Ltd. All rights reserved. Copyright © 2018 IFAC 396 memory block. Peer review©under of International Federation of Automatic Copyright 2018 responsibility IFAC 396Control. Copyright © 2018 IFAC 396 10.1016/j.ifacol.2018.11.338 Copyright © 2018 IFAC 396
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Automatic control system consists of 2 parts, between which the connection is carried out by COM ports: operator panel and software logical unit (SLU) (fig.2).
Operator panel COM port
Software logical unit
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procedure is controlled in an automatic mode. The whole process occurs synchronously in time. While the program is being written, operator errors are taken into account with the possibility of eliminating emergencies. When the operator transmits the data of the diameter and the thickness of pipe wall, by means of the operator's data and the data of the strain gauge, the PLC calculates the actual weight delivered via the set weight and, in this coincidence, it instructs the motor driver to pull the pipe at the rate at which the weight condition is observed as 1 running meter. The programmer writes conditions, formulas, as well as attaches all these data to the time. The detailed analysis of the whole process shows that, the formation of the thickness of the plastic pipes walls with an error in the redistribution of in existing extrusion lines is achieved only by the cost of over-expenditure of raw materials or by a 6-meter length of pipe: 𝜕𝜕𝜕𝜕 𝜕𝜕𝜕𝜕 𝜕𝜕𝜕𝜕 (1) 𝜎𝜎 = 𝑓𝑓(𝜐𝜐, ∆𝜌𝜌, ∆𝑇𝑇𝑟𝑟 , 𝑟𝑟 , ∆𝑇𝑇𝑐𝑐 , 𝑐𝑐 , 𝑑𝑑 , ∆𝑚𝑚)
Sensors Driver
Fig.2. Automatic control system of the formation of a given thickness of polyethylene pipes for the production in extrusion lines This unit is operated by the control software which in its turn consists of 2 parts. The first part software is written in the operator panel and the second one in PLC. The first written part is divided into several parts. They include the pages described on the operator panel for visualization and input operator. The second part software is directly recorded in PLC. Language program LAD (Ladder Diagram) is used for the simplification of the written program. The program recorded in PLC operates the drivers on the base of the date from the sensors. All this process is synchronized in real-time mode. See the sample. The used units are GMT operator panel, PLC company GMT. Software GMT soft version 2.3 for operator panel and for PLC GMT version 5.0.1.4. The connection between the units is carried out via COM port PPI cable. In its turn PLC has its input extensions – input and connection between the main parts of the device is carried out via screened wires for noise immunity system. As input device for PLC, strain gauge, tachogenerator, sensors are used. But relay assembly is taken for output driver. When the machine is turned on for the first time, the monitor opens. After the selection of the operator language, the second window opens. It includes the areas for entering temperature conditions, real temperature visualization, screw speed, the speed of pulling mechanism, motor current, and so on. The operator first enters the required temperature, the data prescribed by the raw material certificate, then the line is considered to be ready for the operation after the cylinder has been heated up. If the temperatures haven’t reached the set values, the software doesn’t give an opportunity to turn on the auger motors. This is an emergency situation for the screw. After heating up, the auger is turned on and the auger turns are set. On the main window the operator has two options of work. The first option is manual; the second one is automatic (weighing batcher). After the operator has tested the line manually, he presses the gravimetric control button and enters the diameter, the thickness of the pipe wall. Then the program recorded on the monitor transmits the data entered by the operator to the PLC where the input information is processed, the weight is calculated per 1 pt. of the meter and the PLC gives the driver the pulling speed which should be pulled via the pulling mechanism. All this
𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
where: 𝜐𝜐 is the extrusion line vibration, ∆𝜌𝜌 is the absolute 𝜕𝜕𝜕𝜕 change of the raw materials density, ∆𝑇𝑇𝑟𝑟 & 𝑟𝑟 relatively is 𝜕𝜕𝜕𝜕 instability in the changes of heating rate of raw materials, 𝜕𝜕𝜕𝜕 ∆𝑇𝑇𝑐𝑐 & 𝑐𝑐 relatively is instability in the changes of cooling 𝜕𝜕𝜕𝜕
𝜕𝜕𝜕𝜕
rate of raw materials, 𝑑𝑑 is instability of prime mover rate 𝜕𝜕𝜕𝜕 and ∆𝑚𝑚 is instability of raw materials mass. Anyway, all these instabilities influence on the accuracy of the formation of the given thickness of the pipes. The ways for eliminating these disadvantages have been proposed to increase the accuracy of the formation of the given thickness of the pipes. Since the strain gauge is attached to a batcher that is connected to the line chassis in the gravimetric batcher for measuring the weight, then vibrations occur which lead to the additional errors in the formation of the thickness of the pipes walls. In this case, an additional batcher not attached to the extrusion lines mechanically is proposed to be used. Raw materials are delivered into an additional bunker, and from there they enter the main bunker. In this case an additional bunker vibration doesn’t take place. Strain gauges for the gravimetric weighing batcher in existing lines are installed under the extruder bunker or suspended above the batcher, which is unacceptable in terms of the vibration interference impacting the strain gauge. Strain gauges are proposed to be installed in the tanker where raw materials will be transported into the bunker. For the solution of the problem with the instability of raw materials density, the software has been changed, additional parameters have been introduced (the raw materials density of the origin certificate for raw materials). Theoretical mass of one running meter of pipe is determined as follows: 𝜋𝜋∙(𝑑𝑑−𝑠𝑠)∙𝑠𝑠∙𝜌𝜌 , (2) 𝑚𝑚 = 1000
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where m is the theoretical mass of one running meter of pipe in kg, π=3,14 (constant value), d is the outer diameter of pipe in mm, s is the thickness of pipe walls in mm, p is the density of the material in sm. For the stability of the length and thickness of the pipe wall with the possible damage, it is suggested to control the weight of the raw material for the production of per 10 cm of the pipe, instead of controlling the weight of the raw materials for producing one meter of the pipe. For this purpose, a gravimetric batcher with corresponding strain gauges and a bridge measuring circuit has been installed and corresponding changes have been made in the program. The proposed method is to automate production forming a standard wall thickness of the pipe by controlling the weight of its running meter. Such a sample is given: Ф110РN10 S=6,6 м=2,190 kg. It is seen from the sample that 2.19 kg of raw material is required to form a pipe wall thickness equal to 6.6 mm with its length of 1 meter. For the implementation of this method, a weight sensor and a control system of the pulling mechanism and a tachometer for viewing and controlling the speed of the pipe moving on the line are used. It should be noted that on plastic pipes depending on the diameter, the pipe should have a certain wall thickness with a possible dispersion in the positive direction. Thus, for a pipe Ф110 PN10, the wall thickness should be 6.6mm + 0.8mm, i.e. 6,6 mm + 0, mm. Gravimeter INOEX gives the results within this thickness, namely 7.2 mm which leads to over expenditure of raw materials. It originates according to the following reasons. When the thickness of the pipe walls approached the record of 6.6 mm, the operator of the lines had to reduce the weight of incoming raw materials in the operator panel via a dispenser in order to approach the lower limit of the wall thickness and, thereby, to reduce the over-expenditure of raw materials. This required the operators of high-skill lines and led to the risk of yielding wall thickness beyond the permissible limits. For reducing the length of the pipe with a possible damage from 6 m to 10 cm, it is suggested to control the weight of the raw material (0.219 kg) for producing each 10 cm of the pipe instead of controlling the weight of the raw material (2.190 kg) for producing one running meter of the pipe. The raw material has a solid form of granules fraction of4-5 mm and is delivered in bags of 25 kg. The raw material is attached by a certificate of conformity, in which its technical and chemical data are indicated. The raw material certificate indicates the percentage of moisture. Raw material is poured into the batcher, which is attached to the extruder. The extruder consists of a cylinder, in which a worm rotates. The cylinder itself is heated by heaters placed on the cylinder. Heating zone is 6-8. The heating temperature is indicated in the certificate and ranges from 1900 to 2100. Moving in the cavity of the cylinder, being melted the raw material moves to the head.
1. At the end of the head, it melts completely and takes the form of a soft monolithic mass. While leaving the head, it naturally loses some mass. The mass differs from its original state. It takes place is due to the evaporation, after heating. From the experiments made at plant Croplast, Baku, the data shown in the table has been obtained. Tabl.1. Dependence of mass loss on temperature and holding time Melting temperature Time limit Weight loss 190 15 0,028 200 15 0,031 210 15 0,032 During heating process, not only moisture but also some plastic components evaporate. Increasing to 16-21% at 2100, plastic also changes its volume from its original state at 230. After its cooling to 230, there aw materials hrinks forming 16-21%. Coming out in the form of a soft monolithic mass, raw material enters the calibrator, where it is pressed against the walls of the calibrator and takes the form of a hollow tube. It takes place is due to vacuum pumps. Moving further along the line, the pipe is cooled to 23 0 by forced water cooling. Further, the pipe is cut into segments. As it has been observed, raw materials undergo three conditions. Solid, soft heated and hard original. While its state is changing, it changes its weight ∆m and volume ∆v. Because of the loss ∆m, which forms ≈0,03%, and it loses its volume ∆v. The instability of the thermoregulatory, which unevenly heats the raw material up in the cylinder cavity contributes to the retention of raw materials and the irregular motion of the raw materials in the extruder, which in its turn influence on the rate at which the raw material mass exits out of the head. While pulling the pipe, the pulling mechanism also has its own errors. The reasons are resulted in the voltage swings, variable load and slip of the pipe from under the caterpillar of the pulling device. The table shows the results of the investigation of the prime mover behavior within 1 hour. Tabl.2. The behavior of the tractor when changing the supply voltage and load Voltage swing, B Load Slip 384 7,3 1,2 396 7,8 1,16 The following table shows the results of comparing the wall thickness during the production of the gravity control pipe of the company INOEX and the company Croplast.
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Tabl.3. The results of the proposed approaches to improve the accuracy of forming the wall thickness of polyethylene pipes The thickness of the wall INOEX Croplast 6.6 7,2 6,8 42.1 45,6 42,7 Thus, the influence of all three factors on the error in the formation of the thickness of the pipe has been eliminated partially. The proposed solutions have been implemented during the production of plastic pipes at the plant “Croplast” (Baku). 3. CONCLUSION In the presented article, more practical ways are proposed for increasing the accuracy of a given thickness of polyethylene pipes in extrusion lines. As a result of its implementation, the error reduces the formation of pipe thickness, saves raw materials, increases the productivity and reduces financial costs (for electricity and labor force). REFERENCES Bronshtein I.N., Semendyayev K.A. (1981). A handbook on mathematics for engineers and students of technical colleges. - Moscow: Publisher “Science”. Extruzionnie linii dlya proizbodstva trub http://newpostavka.ru/linii_po_proizvodstvu/proizvodstvo _trub Mammadov R.G., Novruzova R.Z. (2016). Improvement of the control system of polyethylene pipes in extrusion lines. – Instruments and Systens: Monitoring, Control, and Diagnostics.- № 10,pp. 46-48. Mammadov R.G., Novruzova R.Z. (2016). Control system of polyethylene pipes production in extrusion lines. “Materials of the V International scientific- practical conference “Information Control Systems and Technologies”.- 22th September, Odessa.- pp.32-35. http://www.kazgp.ru/teoriya/31tehnika_i_tehnologiya_proizvodstva_polimernyih_trub.ht ml http://www.plastics.ru/pdf/journal/2014/06/Inoex.pdfBudushee- za AUREX m-line.
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