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Manufacturing procedure computer-aided system in pulp and paper, textile and chemical industries AKVAR

Purpose
Designed for continuous process control density (mass per square meter) and other parameters of the paper and cardboard web, textiles, glass fibers, etc.

Features
Automated system consists of a set of devices that control the basic processes in the production line:
• radioisotope densitometer LEB1 with ionizing radiation source (IRS ) Kr 85
• robotic arm to control the headbox
• software package, which is an integral part of the quality control system.
• The software package has graphical user interface built on the basis of standards adopted in operating systems Microsoft Windows ™

Radioisotope densitometer LEB1

LEB1 is designed for continuous and non-contact control of the weight of paper and cardboard web, textiles, glass fibers, etc. It is used in the automated system of quality of control sheet materials QSC, and as a standalone product.

Radioisotope densitometer consists of two units: a transmitter and a receiver.
LEB1 can be mounted on an electromechanical device of input (bracket), which provides a one-dimensional continuous monitoring of the controlled parameter or on a measurement platform (a scanning device), thereby providing a two-dimensional continuous monitoring of density and other parameters.

Densitometer is equipped with a digital interface type RS-232 or RS-485 interface (baud rates up to 57.6 Kbps) and high-speed interface and high-performance interface CAN (baud rates up to 1 Mbaud) in order to integrate the device with APCS systems.

The densitometer physical principle of operation is based on recording of ionization chamber current induced by β- radiation weakened by the material under study . As an active element the designers used a radioisotope Kr85 placed in a lead cylindrical body to ensure sanitary standards by γ- radiation level. Ionization chamber current is amplified and converted to a voltage transferred by ADC in a 24 - bit binary code processed by microprocessor. Density is determined By magnitude of the measured signal (mass per square meter ) of the material under control . Special measures for temperature stabilization of converting amplifier have been taken . Automatic calibration of the meter.
The sensor has a large range of measured masses at high spatial resolution.

Technical characteristics:
Operating element Кr85
The range of measured masses, g / m2 40-1200
Accuracy of measurement of weight,% 0,2(rlt.)
Ambient temperature, ° C +5…+50°
Dose rate of γ-radiation, mR / h  
on the sensor surface 5
at 1m distance from the sensor 0,036

Robotic arm to control headbox
  • The robot arm is designed for coordinated control homotypic mechanisms of fine adjustment of a parameter, located in one line and having a rotational principle of regulation
  • Enables by the operator's commands or a computer to find the required fine adjustment mechanism and turn its regulatory body at a predetermined angle in any direction, as well as to do algebraic summation of the angles of rotation for each mechanism
  • The main area of application of the device is the paper industry, which requires adjustment of some parameters of the paper web across its width directly in the production process. In particular, the surface density and web humidity by the transverse profile is traditionally regulated by a large number (70) of mechanism , like, valves , each of which is located over a particular area of the web and affect the variable under regulation in the given zone.
Features
  • Using robotic arm instead of equipping of each adjustment mechanisms with individual drive can solve the problem of regulation parameters of the paper web at a lower cost and with greater reliability (since the probability of failure of one of the drive system in proportion to their number in the system).
  • In addition, the individual drives facility require significant structural improvements of existing equipment (headbox, wetting edge jets, steam boxes, etc.)

Robotic arm performs two main tasks:
  1. The first of these is linking up with the required accuracy of the actuator mechanism of the robot to the given precise adjustment mechanism from arbitrary previous position
  2. second operation – carrying out regulation (rotation of the fine adjustment mechanism head by a predetermined angle head

Robot actuator pulls out a grabbing tool seizing fine adjustment mechanism head, followed by a rotation together with the head and after completion of the rotation a grabbing tool retracts , freeing the head. After this the controlling cycle can be repeated with the other output data ( number of fine adjustment mechanism and the rotation angle ) .

The described work control is carried out by an electronic microprocessor unit (process controller ) having a board and keyboard for autonomous control , as well as built-in RS-485 interface for communication with paper web quality control computer. In this case, the control computer program determines the source data for each subsequent cycle of regulation.

Application
  • Pulp and paper industry
  • textile industry
  • chemical industry
Forms of cooperation: small-scale production