SU1256758A1 - Arrangement for automatic control of evaropaton in evaporating apparatus with natural circulation - Google Patents

Description

The invention relates to devices for automatically controlling the evaporation process in a natural circulation evaporator and can be used in the food and microbiological industry.

The purpose of the invention is to increase productivity and increase the cycle of operation of the evaporator.

Figure 1 is a schematic diagram of the device; Fig. 2 is a block diagram of a signal change detection symbol.

The device contains a flow sensor 1 installed on the steam supply line and connected to the input of the regulator 2, the output of which is connected to the actuator 3, also installed on the steam supply line, the flow sensor 4 installed on the supply line of the initial solution and connected to the regulator input 5 flow rate and ratio controller 6, the second input of which is connected to the flow sensor 7 of the one stripped off solution,. and exit - to the executive mechanism

8, installed on the line one stripped off solution. The output of the controller 5 is connected to the actuator

9, installed on the line of the original solution.

In addition, the device includes a vapor pressure sensor 10 installed in the heating chamber I1 of the evaporator apparatus and connected to a differentiating unit 12, the output of which is connected to the analyzer 13 of the signal change sign, the second input of which is connected to the differentiating unit 14, the first output the switch 15, and the second output, with a chamber for setting the circulation rate regulator 16. The sensor 17 of the speed of circulation, installed on the line of circulation of the solution between the heating chamber and the steam separator 18, is connected to the inputs of the differentiating unit 14 and the regulator 16, the output of which is connected to the second input of the switch 15, the first output of which is connected to the second input switch 15, the first output of which is connected to the controller setting chamber 5, and the second to the regulator setting reference camera 2 The block 13 for determining the sign of the change of signals consists of four three membrane relays 19-22, elements 2

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and 24 comparisons, two set points 25 and 26 and throttles 27. Switch 15 consists of a three-membrane relay 28. Relay 19 output is connected to input-: relay 20, which is also connected to setpoint 26 and differentiating unit 14. Relay 20 output is connected via a choke 27 to a deaf chamber of the relay 28. Differentiating unit 12 is also connected with comparison element 23, and differentiating unit 14 with comparison element 24, the task cameras of which are connected to setting devices 25 and 26, respectively. The outputs of the elements 23 and 24 are connected to the inputs of the relay 21, the output of which is connected to the input of the relay, 22, the second input of which is connected to the differentiating unit 12.

The device works as follows.

The control loop for steam supply, consisting of sensor 1, controller 2 and actuator 3, provides stabilization of steam consumption in the heating chamber, and the control circuit consisting of sensor 4, controller 5, actuator 9, - stabilization of the solution flow rate for the installation. The task on the controller 5 is supplied through the switch

15 from the regulator 16 of the circulation rate, depending on the value of the signal from the sensor 17. The control loop, which includes sensors 4, 7, ratio controller 6 and actuator 8, controls the evaporated solution flow in a given ratio.

At steady state operation, the signal from the sensor 17 of the circulation rate 17 is fed to the regulator

16 through the switch 15 into the chamber of the setting of the controller 5. An increase in the flow rate to the installation causes an increase in the level and, consequently, an increase in the circulation rate. The differentiating unit 14, according to the signal from the sensor 17, determines the magnitude of the increment DUc. If the increment does not exceed the permissible limit, then the device operates in a manner similar to the steady state. If the level value unacceptably increased j, the pressure in the heating chamber increases and, according to a signal from the sensor 10, the differentiator 12 determines the branch rate of the increment lR. The signal of the increment value enters the block 13, which determines the sign of the increments aP and lu,. If yr is O and V.

Oh, then a regulating signal 16 is outputted to the controller 16, which is proportional to the value of the pressure increment AP. The reference to controller 5 is issued in a manner similar to the steady state. Thus, the signal from block 14 UV O locks relay 20 and relay 28 passes to controller 5 a signal from controller 16. At the same time, the signal fed to comparison element 24 together with signal from sensor 26 causes it to go off. and the output signal of the element 24 is fed to the input of the relay 21, which is connected according to the scheme of the element I, which is triggered when two positive signals from block 12 and 14 appear at the inputs. When the signal LP 0 appears at the input of element 23, the value of the signal from the setting device 25 at its second input, lement 23 is activated and vschaet signal to the second input of the relay 21 which in turn relays a signal to feeding port 22, and causes its actuation signal with its second input from differentsirztoschego unit 12 goes to block 16.

With a decrease in the circulation rate due to scale formation due to a decrease in the heat flow according to a signal from the sensor 17 in the differentiating unit

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14, the magnitude of the change in the circulation rate of the AUC is determined. When nakipet - the formation of pressure is observed in the heating chamber and the differentiating unit 12 on a signal from the sensor Yu determines the magnitude of the pressure change i or P. Block 13 determines the sign of the deviation

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At dP 0, l outputs a signal to switch 15, which is triggered, and the signal from controller 16 begins to flow into the reference chamber of controller 2, rather than controller 5.

The block 13 (figure 2) works as follows. When a signal LP 0 is generated from block 12 at the input of relay 19, which exceeds the pressure in the chamber from setpoint 25, relay 19 is activated and outputs a signal to relay 20. If the second input of relay 20 receives from block 14 a signal uV 0 that is less than pressure setting in the chamber, the input of which receives a signal from the setting device 26, then the output signal of the relay 20 through the throttle 27 is fed to the switch 28 and slams the nozzle, which passes the signal to the regulator 5., and the signal from the regulator 16 goes to the regulator 2.

In the presence of the signal of the LC 0, the element 24 does not work and there is no signal on one of the inputs of the relay 21. As a consequence, the correction signal to the controller 16 is not received.

Steam t --O-4 fJ-Uparinnni 7 solution

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Editor M.Tovtin

Compiled by T.Golenshina

Tehred I. Veres Proofreader O. Lugov

Order 4854/3 Circulation 663 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow., Zh-35, Raushsk nab. D. 4/5

Production and printing company, Uzhgorod, Projecto st., 4

Claims (1)

DEVICE 'FOR AUTOMATIC REGULATION OF THE EVAPORATION PROCESS IN A VEHICLE WITH A NATURAL CIRCULATION, containing flow sensors of the initial and evaporated solutions, connected via a ratio regulator to the actuator, a steam pressure sensor in the heating chamber, a circulation speed sensor mounted to the circulation tube regulator, flow regulators of the initial solution and steam, characterized in that, in order to increase the productivity and cycle of the installation, it optionally contains a block for determining the sign of the change of signals, a switch, a steam flow sensor, the first and second differentiating blocks, while the steam pressure and circulation speed sensors are connected to the inputs of the corresponding differentiating blocks, the outputs of which are connected to the block for determining the sign of the change of signals, the outputs of which are connected to the camera setting the speed controller of the circulation speed and with one of the inputs of the switch, the other input of which is connected to the output of the speed controller, and the outputs of the switch anes cameras specify the initial flow regulator solution and vapor flow controller connected to the steam flow rate sensor SU „, 1256758