SU1576818A1 - Device for controlling process of drying - Google Patents

Abstract

The invention relates to the automatic control of the drying process of vegetables, fruits and wild plants in drying chambers and allows for improved control accuracy. The temperature in the drying chamber is measured by means of a temperature sensor, compared with the value set in the thermostat specified at this stage according to the program, and according to the results of the comparison, a thermal electric heater is turned on or off. The drying mode is determined by the setting unit of the temperature control program, designed to maintain the three heat carrier temperatures set by means of setting units 12–14 for three equal or different time intervals set by the corresponding time relays 15–17. 1 hp f-ly, 5 ill.

Description

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The invention relates to the field of automation of drying processes, relates to a device for controlling the drying process and can be used in the food industry, agricultural production and household appliances to control the drying process for vegetables, fruits, a year and mushrooms.

The purpose of the invention is to improve the accuracy of control.

FIG. 1 shows the main camera, general view; in fig. 2 shows section A-A in FIG. one; in fig. 3 shows a section BB in FIG. 2; in fig. 4 shows a section B-B in FIG. 2; in fig. 5 is a block diagram of an apparatus for controlling the drying process.

The drying chamber contains a heat-insulated casing 1, a drying volume 2, a ventilation chamber 3, a recirculation channel 4, the casing 1 being on top covered with a table top 5, and the front side is closed by a door 6 with a viewing window 7, below the door 6 there is a panel 8 placed on The suction windows 9, a damper 10 equipped with a handle 11, setting devices 12-14, a time relay 15-17 and a push-button station 18 are located there. In the drying volume 2, the trays 19 are installed in which the drying product is poured. The drying chamber is also equipped with a system of forced circulation of the coolant (air), including a fan 20 with a driving electric motor 21, a thermal electric heater (TEN) 23 installed in the circulation channel 22, an exhaust window 24 and a recirculation channel 4. The device for controlling the drying process contains switch 25 of the drying chamber, buttons 26 "Start and 27" Stop of the button station 18, switch 28 of the heaters 23. Thermostat 29 connected to the setting device 30 of the temperature control program, temperature sensor 31 and the switch 28 of the heating element 23. The setting device 30 of the temperature control program contains temperature controllers 12-14, time relay 15-17, the first logical element BANGE 32, a three-position switch 33 with control elements 34 and 35, and temperature control devices 12-14 are associated with inputs of the three-position switch 33, and its output - with the input of the thermostat 29. Time relay 15 is connected to time relay 16 and the first input of the first BAN 32 logic element, the output of which is connected to the control body 34 of the three-position switch 33. Time relay 16 is connected tocontrol unit 35, switch 33, time relay 17 and the second input of the first BAN 32 element. The output of the timer relay 17 of the temperature control setting device 30 is connected via OR OR 36 to the first input of the second BAN 37 logic element, and the output of this element is connected to the drying switch 25 cameras. A start button 26 is connected via the second memory element 38 to the second input of the second BAN 37 logic element. The button Stop 27 is connected to the second input of the logic element OR 36. The switches 25 and 28 are equipped with control elements 39 and 40. The output of the thermostat 29 through the logical element NOT 41 is connected to the relay 15 of the time setpoint 30 of the temperature control program. The elements BANTS 32 and 37 include the logical NOT 42 and 43, as well as the logical elements AND 44 and 45. The temperature controller 29 is designed as a summing unit 46, a diode 47 and a starting unit 48, connected

consistently among themselves. At the time relay output 15, the first memory element 49 is mounted.

As the driver for the temperature control program 30, a small electronic computational bus can be used.

Magnet-valve logic element is proposed as logical elements HE 41 - 43. As logic elements OR 36, And 44 and 45, nsg can be used, for example, choke magnetic valve logic elements containing serially connected diode group 50-52 (Fig. 5), control circuit of chokes 53-55, electrical chokes 56- 58 and the output circuit of chokes 59-61.

0 Potentiometers - adjustable voltage dividers, built from active resistances can be used as setting points for 12-14 temperatures.

As a relay 15 -17 time can

5 any time relays having the ability to adjust for a given product drying time, for example a motor time relay, can be selected.

As the temperature sensor 31, for example, a resistance thermometer can be used, the output of which creates a voltage U proportional to the temperature T.

As the control bodies 34, 35, 39 and 40 of the switch 33 and the switches

5 25 and 28 electromagnets can be applied.

A device for controlling the drying process works as follows.

The product to be processed is laid out on trays 19, which are routinely installed in the drying volume 2. Using the handle 11, kinematically connected to the valve 10, set the desired flow area of the suction windows 9. The temperature control setting device 30 adjusts the set drying mode, for which the setting devices 13, 12 and 14 set the desired temperature of the coolant T, TZ, Tz, and the relay 15-17 time - the duration of exposure of these temperatures t, tz, is and the total time

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drying process t, equal to + / 2-of. After that, having tightly closed the chamber door 6, the button 26 of the button station 18 is pressed. The signal X 1 enters the second memory element 38, at the output of which a signal is formed which remains unchanged during the entire drying process and arrives at the second input of the second logic gate. element BANGE 37. Since at the same time at the first input of the second logic element BANGE 37 signal, then the output element 37 signal. This signal acts on the control unit 39 of the switch 25, including the motor 21 of the fan 20, the power supply of the thermostat 29 and the setpoint 30 of the temperature control program.

In the initial position, the signals Z Ys 0, the switch 33 under the action of the springs is installed in the middle position, so that T is T. In this case, the temperature T of the coolant measured by the sensor 31 of the temperature in the drying volume 2,. The signal from the output of the thermostat 29 () is fed to the control unit 40 of the switch 28, thereby turning on the power supply to the heating element 23. The fan 20, driven by the motor 21, draws air through the suction ports 9, the recirculation channel 4. Next, through the circulation channel 22, the heat electric heating element 23, the obtained coolant enters the drying volume 2. The coolant alternately passes through the mesh trays 19, having dried the product laid in them. The spent heat carrier is partially removed from the drying cabinet through the mesh exhaust port 24, and partially enters the recirculation channel 4 for the subsequent drying cycle.

As soon as the temperature T of the coolant becomes greater than the set one, i.e., the signal Zi at the output of the thermostat 29 becomes equal, the contacts of the switch 28 open and the heater 23 is turned off. Simultaneously, the signal at the output of the logical element HE 41 gives the command to turn on the first relay 15 of setpoint 30, which is set to count time t. As soon as T.T.L.-T, the signal Z2-1 again gives the command to turn on the heating element 23, etc., so that the temperature is maintained in the drying volume 2 for a time t.

After the time t-t has elapsed, the time relay contacts 15 close and the signal at its output goes to the first memory element 49, the output of which produces a signal Y that does not change during the entire drying process. This signal gives the command to turn on for 16 times and goes to p and B, UV, the first logical element. Forbid As at this moment there is a signal at the second stage, at the output of this element

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This BAN 32 signal equals Z | 1, which causes the control body 34 to switch the three-position switch 33 to the left position, whereby the signal TL Tz supplied to the input of the thermostat 29 appears at the output of this switch, while the drying chamber operates in the mode of maintaining the coolant temperature for a time 2, on which the second time relay 16 is set up, similarly to that described.

When the time elapses from the beginning of the drying process, the time relay contacts 16 are closed and the signal is fed to the second input of the first BANLE 32 logic element, turns on the time relay 17 and is fed to the control body 35 of the three-position switch 33. Since the signals 33 switch to the right position and the thermostat's input are given a Tl 7z signal. In this case, the drying chamber operates in the mode of maintaining the temperature of the coolant TzzTz in the same way as described until its contacts are closed after the setting time / 3.

When this signal arrives at the input of the logic element OR 36, at the output of which signal Zs 1 appears. At the output of the second logic element BANGE 37, the signal is present, therefore the contacts of the switch 25 are opened by the spring. Electric motor 21, heating element 23, thermostat 29 The setting device 30 is disconnected from the power grid and the drying process is stopped, which, if necessary, can be given a light or sound signal, to the delivery unit of which the command Za-1 is given.

If you need to maintain not three levels of temperature T, T%, T3, but two T and 2 or only one T, time relays 17 or time relays 17 and 16 are set to time or and the device operates as described. If it is necessary to stop the darling process performed on a given cycle without waiting for it to finish, press the button Stop Button 27 of the button station 18. Press the signal to the second input of the logic element OR 36, the signal from which becomes equal to Zs-1, and the drying process stops similar to that described.

Claims (2)

1. A device for controlling the drying process, comprising a drying chamber, a fan with an electric motor and a switch, an electric heater with a thermostat connected to the setpoint and temperature sensors, a push-button station. .r ... Ston, characterized in that, in order to improve the control accuracy, it additionally contains two temperature controllers, a three-position switch with two switching elements, three time relays, two BREAD logic elements, two memory elements, a logical OR element and the logical element is NOT, all temperature adjusters are connected to the inputs of a three-position switch, the output of which is connected to the input of the thermostat, the output of which is additionally connected via the logical element NOT to the input of the first time relay connected by its outputs through the first memory element with the input of the first logic element BANGE and the input of the second time relay, the outputs of which are respectively connected to the second switching element, the second input of the first logical element BAN and the input of the third time relay whose output is connected to the first input logical element OR, while the second input of the last is connected to the button “Stop of the button station, and the output of this element OR is connected to the first input of the second logical element BAN, the second input Which is connected through the second memory element to the button “Start the button station, and the output of the second logic element BANGE is connected to the switch of the fan motor. 2. A device according to claim 1, characterized in that the thermostat is made in the form of successively connected summing unit, diode and starting unit. 31 3 20 21 7 19. 19 Rig. 2 6-6 five 7 Phage. four  f ji, 2829 r thirty ZQ S 25