SU666526A1 - Moulding process control method - Google Patents

Description

one

The invention relates to process automation. chemical production and can be used to optimize the forming conditions of the hydrated cellulose film.

There is a known method for controlling the process of molding polymeric materials in a spinning unit by changing the concentration of the precipitated solution depending on the physicomechanical parameters of the material 1.

A disadvantage of the known method is a decrease in the strength of the film when changing over a wide range of the load of the aggregate (consumption of polymer solution and the speed of the exhaust devices).

In order to increase the strength of the polymeric material according to the proposed method, the polymer solution consumption and the speed of the stretching devices are measured, and the concentration of the precipitant solution is changed extremely by the maximum value of the polymer consumption and the speed of the stretching devices before the load of the aggregate changes. process support equal precipitant concentration

until the beginning of the transition mode of the unit.

In addition, when changing the polymer consumption rate and the speed of the exhaust devices, the concentration of the precipitator is measured at times of reverses, and the concentration maintained during the transition process is set depending on the measured values according to the following law

C; ..- C:

Н1

+ S.,

where Cj and Cj, is the precipitate concentration value in i-TOM and i + 1 reverse,%,

K - coefficient taking into account the form of the static characteristics of the process.

The method is explained in the drawing.

The hydrated cellulose film 1 is formed as follows. The solution of polymer A is fed through a die plate 2 into a solution of precipitator B of a molding bark molding matsina.

Claims (2)

In order to strengthen the freshly formed film, it is stretched using a stretching device 4. Next, the film is subjected to finishing and drying (not shown). The control method is as follows. The precipitator concentration is measured by sensor 5 and the film strength is measured by sensor 6. The flow rate of the polymer solution and the speed of the extraction devices are monitored respectively by sensors 7 and 8. The output signals of sensors 5-8 are fed to the inputs of the control unit 9 With this block, the consumption of the agent B is corrected (affecting the actuator 10). First, test movements of the actuator are carried out, the direction of movement of which changes depending on the measured value of the film tension, maximizing its value, i.e. ultimately strength. Mathematically, the algorithm for trial changes in the concentration of the precipitator can be written as follows: Sign dC sign (lr - D, where DC is the change in the concentration of sediment D is the dead zone; DR | is the increment of film strength. When the load and modes of the injection molding machine change , the speed of the exhaust devices), the search for the optimal mode is temporarily stopped and the concentration of the precipitator solution is set equal to the concentration at the moment of the start of the transient process on the load of the injection molding machine. using the sensor of the polymer solution flow rate and exhaust speed, indicate the moments of load change, implement the algorithm ji at | drrp1 d or | dU at | D2 о at | ddrp | DI | dUduiD2., where it is) DUCU-, L, D2 deviation and zones permissible values of deviations of the flow rate of the polymer solution (S ™) and the speed of the exhaust device (). At the moment, the utflavlny block stops the search mode, memorizing on the executive mechanism the value of the control signal that precedes the moment the load of the injection molding machine changes. After the end of the search fluctuation cycle, the precipitator concentration, corresponding to the maximum value of strength, is expired, realizing the p - p algorithm. Sfi i V к The average value of the precipitator concentration at K 2 has the form When the static characteristic is shifted, the system re-searches in manual or automatic mode of operation, similarly to that discussed above. The proposed method is implemented with the help of serial elements and automation equipment. The study of the model of the system implementing the method on the EMU MN-7 showed that with a constant object time of 0.5–1 min and a delay of 1.5–2 min (actual installation data taking into account the measuring instrument dynamics), the search time does not exceed 60 min, search losses 1.5%. In the study was used extreme regulator ARS-20. The proposed method allows to reduce the unevenness of properties and increase the strength of the film by maintaining more stable conditions for its production, to reduce the specific consumption of the polymer solution and the loss of the film. In addition, the quality of the film is improved and its waste is reduced. The method is used in the production of fibers and films, developed by a standard control system. Claim 1. Method of controlling the process of molding polymeric materials in a spinning aggregate by changing the concentration of the precipitant solution depending on the physical and mechanical properties of the material, characterized in that, in order to increase the strength of the polymeric material, the flow rate of the polymer is measured and the speed of the exhaust devices, and the concentration of the precipitant solution is changed extremely by the maximum value of the polymer consumption rate and the speed of the exhaust devices until the load of the unit changes, at m concentration of the precipitant during the transient support. equal concentration of precipitator until the beginning of the transitional regime of the aggregate. 2. A method according to claim 1, characterized in that when the polymer consumption rate and the speed of the exhaust devices change, the precipitator concentration is measured at the time of the reverses, and the concentration maintained during the transition process is determined depending on the measured values according to the following law. Q., gDeS, I Oj - the value of the concentration of the precipitator in i-OM and I + 1 reverse,%; K - coefficient taking into account the form of the static characteristics of the process. Sources of information taken into account during the examination 1. USSR Copyright Certificate If S21313, cl. C 13 D 1/10. 1976.