SU1508999A1 - Apparatus for controlling concentrationg of carbon dioxide in the air of hothouse - Google Patents

Abstract

The invention relates to agriculture, in particular, to industrial vegetable growing and floriculture of protected ground. The purpose of the invention is to optimize the photosynthesis process and save natural gas by continuously monitoring and controlling the concentration of carbon dioxide in the greenhouse air. A device for regulating the concentration of carbon dioxide in the greenhouse air contains a sensor 1 of carbon dioxide concentration, made in the form of a gas analyzer with an electrical output. The sensor 2 for irradiating plants is designed as a photogenerator. A thermocouple is used as the sensor 3 for the internal air temperature. The sensors are installed in the greenhouse at the height of the plants and connected to the corresponding inputs of the computing unit 4. The duration of the output pulses of the pulse regulator 5 is proportional to the input signal, and the polarity is the polarity of the output of the computing unit 4. The matching unit 6 is connected to the input of the on-off regulator 7. The on-off regulator 7 includes a reversible drive 8, a carbon dioxide concentration setting device 9, a reference element 10 and a filter 11. The output of the matching unit 6 is connected to the input 12 pa carbon dioxide. The device allows to shorten the growing season and increase yields. 2 hp f-ly, 7 ill.

Description

FIG. one

3150

The invention relates to agriculture, in particular to industrial vegetable growing and planting of protected ground.

The purpose of the invention is to optimize the photosynthesis process and save natural gas by continuously monitoring and controlling the concentration of carbon dioxide in the greenhouse air.

FIG. 1 shows a functional diagram of a device for controlling the concentration of carbon dioxide in the air of a greenhouse; Fig, 2 - functional diagram of the generator of carbon dioxide | Fig. 3 shows the functional diagram of the matching unit, (the first option); Fig. 4 - the same, the second option; FIG. 5 is a block diagram of a computing unit; FIG. 6 is graphical. the dependence of photosynthesis of plants as a function of carbon dioxide concentration and irradiation; Fig. 7 shows a graphical dependence of photosynthesis of plants as a function of carbon dioxide concentration and air temperature in the greenhouse.

A device for controlling the concentration of carbon dioxide in the greenhouse air contains a sensor 1 of carbon dioxide concentration, made in the view of a gas analyzer with an electric B51 IN, a plant irradiation sensor 2 made in the form of a photogenerator, a sensor 3 in the internal air, made in the form of a thermocouple, - which are located in the greenhouse at the height of the plants and whose outputs are connected to the inputs of the computing unit 4. The output of the computing unit (positive or negative polarity) is connected to the input pulse A regulator 5, dl) the output impulse blinkness of which is proportional to the input signal, and the polarity - the polarity of the output of the computing unit 4, the output of the pulse regulator 5 through the matching unit 6 is connected to the input of the two-position regulator 7 a versatile drive 8, a carbon dioxide concentration setting device 9, a reference element 10 and a filter 11 connected in series with the output of the matching unit 6 connected to the input of the reversing drive 8 of the carbon dioxide concentration controller 7, output - S filter 11 connected to the input of carbon dioxide generator, and

five

0

0 5 0 5 Q

the second input of the reference element 10 is to the output of the carbon dioxide concentration sensor 1.

The filter 11 consists of two parallel-connected thyristors of various structures connected to a power source, control thyristor electrodes connected to the outputs of the reference element 10, and separate thyristor outputs connected to the inputs of the carbon dioxide generator 12.

The carbon dioxide generator 12 comprises an atmospheric-type burner 13 placed inside a box-section chamber. Inside this chamber, a ignition mechanism 14 and a thermocouple 15 are contained. The burner communicates with a source of natural gas by a pipeline, on which a solenoid valve 16 is installed. The generator control circuit 12 contains a logic circuit DELAY 17, the input of which is connected to the output + of filter 11, and the outputs to the inlet of the solenoid valve 16 and the ignition mechanism 14, and the logic circuit BANGE 18, the output of which is connected to the inlet of the solenoid valve 16, one input to the outlet of the thermocouple, and the second, prohibiting, to the output of the negative polar STI - r6 filter 11, inlet thermocouple 15 is connected to the output of burner 13, the burner inlet One process is a natural gas stream, the second - the output of the ignition mechanism 14, the second output of the burner 13 is a carbon dioxide stream COg,

Matching unit 6 contains two thyristor switches 19 and 20, coils 21 and 22 of a reversible magnetic actuator and a filter 23 containing two tanks, each of which is connected in parallel to one of coils 21 and 22. A thyristor switch 19 with a coil 21 and a thyristor switch 20 with a coil 22 form two parallel circuits connected to terminals 24 and 25 of the AC source. The control electrode of the thyristor switch 19 is connected to the output of the positive polarity of the pulse controller 5, and the ugly electrode of the thyristor switch 20 to the output of the negative polarity of the pulse controller 5,

Computing unit 4 contains a channel 26 for calculating the optimal from the point of view of photosynthesis of the concentration of carbon dioxide in the greenhouse air as a function of the irradiation F, channel 27 for calculating the optimum value of carbon dioxide for the photosynthesis of the temperature of the internal air of the greenhouse, channel 28 the calculation of the specified rate at which photosynthesis will have a maximum) of carbon dioxide concentration and the channel 29 for calculating the difference liCO between the current value of the CO concentration in the greenhouse air and In this case, the inputs of the channel are 26 and 27 connected to the outputs of sensors 2 and 3 of the irradiation F of plants and the temperature tg of the internal air of the greenhouse, and the outputs to the inputs of the channel 28 of the C0 | 2 calculation, which is connected to the input of the channel 29 calculating the difference ± СОSO, the second input of which is connected to the output of sensor 1 of carbon dioxide concentration in greenhouse air, and the output of channel 29 to the input of pulse controller 5i. The device for controlling the concentration of carbon dioxide in greenhouse air works as follows.

The current value of carbon dioxide concentration COj (t1 is monitored by sensor 1, the irradiation of F plants by sensor 2, the temperature tg of internal air by sensor 3. Information from sensors 1 - 3 is fed to the input of computing unit 4, where, based on the algorithm

, 5 f (F, te),

where is the (optimal) concentration of carbon dioxide in the greenhouse air, at which the maximum photosynthesis of plants occurs;

t g - the current value of the internal air temperature of the greenhouse;

F is the current value of irradiation of plants,

A ± i CO signal of positive or negative polarity is produced, the magnitude of which is proportional to the difference between the current and the set values of carbon dioxide concentration, and the sign indicates the sign of the deviation of the current value from the optimal one. In doing so, channel 26 calculates the value of the function

WITH

If

WITH

gk,

(one ).

0

where CO p - the optimal value

concentrations of carbon dioxide in the air of the greenhouse. with current values of irradiation of F plants;

CO and - the maximum value of the concentration of carbon dioxide during irradiation

F - “so;

T is a constant, determined experimentally, depending on the appearance and stage of plant development (Fig. 6). In channel 27, in a similar way, calculates em — the value of the concentration of carbon dioxide.

gas at which it is reached

from go

maximum photosynthesis at the current temperature tg of internal air according to x ly

  rf

WITH

2 ..

 WITH

2, Xi

(one ).

five

where sb

WITH

-z-tc

Ik

0

-at

five

0

optimal concentration of carbon dioxide;

the maximum concentration of carbon dioxide at a temperature tg - oo; constant, determined experimentally, depending on the type and stage of plant development (Fig. 7). Channel 28 calculates the average

arithmetic concentration value

CO, and based on the algorithm

gp. 2

in channel 29, the difference ± ± .CO between the current concentration of carbon dioxide COj and the calculated C0. 5 The signal t CO is fed to the input of the pulse controller 5, which results in the appearance of a signal at the output in the form of pulses, the duration of which depends on the value of the input signal, and the polarity is proportional to the polarity of the output of the pulse regulator. As a result, at the input of the thyristor switch 19 (20) Matching Block 6 a control signal appears. With a positive U U CO sign, the thyristor switch 19 is opened and along the circuit the clamp 25 of the power supply - the coil 21 of the reversing magnetic starter - the cathode of the thyristor 19 - the clamp 24 of the source0

five

The power supply current is flowing. a half-wave variable voltage, and the actuator 8 is turned on, providing the setting of the setting device 9 in accordance with the output of + SOL. Reliable holding of the contacts of the magnetic actuator when the coil 21 is turned on during the absence of a negative half-period is achieved by turning on the filter 23 parallel to the coil 21. When the output signal changes from ISO to negative, the clamp 24 of the alternating voltage source — the thyristor switch 20 –– and the second filter capacity 23 - power supply terminal 25. At the same time, the actuator 8 reverses and sets the carbon dioxide concentration setting unit 9 to the position prescribed by the computing unit 4. As the drive 8 setting unit 9 of the carbon dioxide concentration in the greenhouse air is switched on by pulses that tend to decrease in duration as the current carbon dioxide concentration approaches gas to the prescribed, overshoot is excluded. The carbon dioxide concentration value set by setting unit 9 is continuously compared by element 10 with the current value measured by sensor 1, and if they do not match, a positive or negative polarity signal appears at the input of filter 11 and is applied to the control electrodes of the thyristors of filter 11. Depending on the polarity of the signal on the code of the comparison element 10, one of two signals at the inputs t appears on the carbon dioxide generator 12. If a given value of carbon dioxide concentration exceeds the current value of CO, a signal at the input of a positive polarity takes place, which is. turns on the logic circuit DELAY 17 One of its output signals turns on the solenoid valve 16, the second - the ignition device 14. Natural gas through the open valve 1 b comes to the ignition mechanism 14 and ignites. The ignition mechanism torch washes the hot junction of thermocouple 15, at the output of which thermoelectromotive force appears. After the thermocouple 15 has fully warmed up, its output signal, which is fed through the BREAK logic circuit to the input of the coil of the solenoid valve 16, keeps the valve in the middle position after the input signal disappears from the DELAYING logic circuit. The duration of this input signal is set equal to or longer than the warm-up time of the thermocouple. In this position, the solenoid valve 16 directs natural gas to the burner 13 and the ignition mechanism 14, which ensures the normal operation of the carbon dioxide generator 12.

. As the greenhouse air is saturated with carbon dioxide, its concentration approaches the target value and then exceeds it. In this case, the signal at the input of the positive polarity of the carbon dioxide generator 12 disappears and appears negative, which prohibits the thermocouple. The output signal of thermocouple 15 does not pass through the BREAK logic circuit, the solenoid valve 16 is closed, shutting off the flow of natural gas from the source to the burner 13, and the carbon dioxide generator 12 is turned off. It is restarted in the same way as before.

A device for controlling the concentration of carbon dioxide in the greenhouse air saves natural gas and intensifies the photosynthesis of plants, which in turn leads to shorter vegetation periods and higher yields.

Claims (3)

1. A device for regulating the carbon dioxide concentration in the greenhouse air, containing a carbon dioxide concentration sensor, a two-position regulator with a carbon dioxide concentration indicator, and a carbon dioxide generator including a combustion chamber with a thermocouple, a pilot mechanism and a burner, the latter of which are connected to the electromagnetic a valve installed on the pipeline for supplying natural gas to the greenhouse is connected to a source of natural gas, and the burner outlet is connected to the thermocouple and concentration sensor inputs carbon dioxide, characterized in that, in order to optimize the photosynthesis process of plants and to save natural gas by continuously monitoring and regulating the concentration of carbon dioxide in the air of the greenhouse, it is equipped with sensors for irradiating plants and the internal air temperature of the greenhouse, a computing unit, a pulse controller, a matching signal, and the outputs of the sensors for carbon dioxide concentration, irradiation of plants and the internal air temperature of the greenhouse are connected to the corresponding inputs of the computing unit , the output of which through the pulse regulator is connected with the input of the matching unit, while the output of the latter is connected to the input of the two-position controller, the output one of which is connected to the inlet of a carbon dioxide generator. 2. The device according to claim 1, about 1 tl and - giving with the fact that the two-position regulator is equipped with a series-connected carbon dioxide concentration control unit, a comparison element and a filter, and the control unit The concentration of carbon dioxide is equipped with a drive, the input of which is the input of a two-position regulator, and the output of the latter is the output of the filter, while the second input of the reference element is connected with the corresponding output of the carbon dioxide concentration sensor. 3. The device according to Claims 1 and 2, that is, that the carbon dioxide generator is equipped with DELAY and BAN logic, while the prohibiting input of the latter is connected to the negative polarity output of the on-off controller, the other input is connected to the output thermocouple, and the output of the BAN circuit - with the first output of the coil of the relay of the solenoid valve, the second output of which is connected to the first output of the logic circuit DELAY, the second output of the latter connected with the input of the ignition mechanism, and the input connected to the output of the positive field p spine on-off regulator. WITH ) + (P) FIG. 3 Fyg. FI.5