SU1230514A1 - Arrangement for automatic control of watering - Google Patents

Description

The invention relates to agriculture, namely, to devices for the automation of irrigation of greenhouses, greenhouses, orchards and vegetable gardens.

The aim of the invention is to improve the quality of irrigation.

FIG. 1 is a block diagram of an automatic irrigation control device; in fig. 2 is an electrical diagram of the water supply comparison and control units; in fig. 3 - graphs of the resistance between the ground and the electrodes.

The automatic irrigation control device contains a stabilized power supply unit 1, a water supply control device 2, a comparison unit 3 with threshold elements, excavators 4, made, for example, in the form of a contour covering the irrigated area, and two horizontal electrodes: the lower 5 and the upper 6 The upper electrode 6 by the contacts 7 of the water supply control device 2 is turned off during the irrigation period.

The water supply control unit 2 and the comparison unit 3 with threshold elements in the water supply control devices operating on the principle of measuring soil active resistance can be performed, for example, as shown in FIG. 2

The water supply control unit 2 may include relays 8 and 9 (Fig. 2), contacts 10 and 11, solenoids 12 and 13 with hydrosars and motors 14 and 15, unit 3 comparison - transistors 16-19, measuring bridge with resistances 20- 23 adjusting bowls 24 and 25, measuring device 26 with additional resistance 27 and soil resistance 28 and 29, connected in parallel or in series to resistance 20.

The automatic irrigation control device operates as follows.

A variable voltage is supplied to the automatic irrigation control device, which in the power supply unit 1 is transformed into a safe voltage, stabilized and supplied to the control unit 3 comparison. At normal soil moisture, the current from the comparison unit 3 (through the measuring bridge) flows through the earthing switch 4, the soil and the electrodes 3 and 6 to the minus power supply unit 1, which corresponds to the humidity control

five

0

five

0

five

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total active soil layer: upper and lower. Drying the soil corresponds to an increase in resistance between the grounding conductor and the electrodes. When the resistance reaches the threshold value, a signal is supplied to the water supply control device 2, which turns on watering and switches off the upper electrode 6 by contacts 7.

During the irrigation period, the current passes through the earthing switch 4, the soil and the electrode 5, i.e. only the resistance of the lower soil layer is controlled. When it is reduced to the lower threshold value, a command is given to stop the water supply and the circuit switches to the initial state.

A specific example is the system of automatic control of self-propelled sprinkler systems depending on the actual soil moisture, which operates in two modes. The first mode provides for automatic opening of the hydrant to start irrigation. Due to a decrease in the actual soil moisture, its total resistance 28 increases, which leads to the unbalance of the resistance bridge 20-23. The imbalance signal is amplified by the transistor 16 and opens the transistor 17. Relay 8 is triggered and contacts 10 turn on solenoid 12, which mechanically opens the hydrant and switches electroautomatics to standby mode using contacts 14 and 15. Transistor 18 is locked with an unbalance signal. Irrigation stops at the moment when the actual moisture of the soil layer exceeds a predetermined limit ..

The second mode provides for automatic shutting off of the hydrant to stop irrigation. Due to the increase in the actual soil moisture, its total resistance 28 decreases, which leads to the unbalance of the resistance bridge 20-23. The mode unbalance signal is the reverse of the first mode. It is amplified by transistor 18 and opens transistor 19. Relay 9 triggers and turns on solenoid 13, which mechanically blocks the hydrant and switches electroautomatics to standby (first) mode using contacts 14 and 15. Transistor 16 is opened by the incoming unbalance signal. Irrigation resumes at the moment when

312

the moisture of the soil layer becomes less than the lower limit.

The scheme does not indicate the elements of protection and manual control. To implement the proposed invention, electrode 5 should be placed in the lower layer at the level of the most dense mass of the roots of irrigated plants, introduce an additional electrode 6 placed in the upper soil layer and switched off by contacts 7 for the time of water supply. The contacts 7 can be disconnected and mechanically connected with the contacts 15 of the junction 13 (Fig. 2, dashed lines) J of the closing and have a mechanical connection with the contacts 14 of the solenoid 12; controlled relay contacts 8 or 9.

The advantage of the irrigation automation scheme in the presence of a switchable electrode in the upper soil layer is seen when comparing the graphs in FIG. 3. The upper graph of the change in soil resistance (moisture) during the operation of the irrigation device corresponds to the presence of one electrode, the lower graph to the presence of two electrodes, where the area fld is the decrease in resistance

144

soil due to the inclusion of electrode 6 after the end of irrigation, section C 0 - increase in soil resistance due to disconnection of electrode 6. Thus, with equal duration of irrigation and drying of soil (see slope of resistance change lines) in the second case, the resistance spread is less, R K „„, - Кл, „m This means that in the second case the humidity mode is closer to the optimal one than in the first one.

Thus, connecting two soil electrodes to the device controlling the soil moisture — the lower one and the upper one — that is turned off by additional contacts for the irrigation period — makes it possible to determine in due time the drying of the entire active soil layer and the adjacent air layer and reliably pick up the moment of moisture from the lower soil layer . The presence of a second electrode that can be turned off during the irrigation period allows one to constantly maintain the humidity close to the optimum, increases the yield of the crops to be watered and increases their resistance to diseases.

4i: p - cz i: 3 - d.28

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HVH

Noke

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Editor I.Rybchenko

Order 2465/3 Circulation 679 Subscription

VNIIPI USSR State Committee

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

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

Compiled by G.Paraev

Tehred I.Gaidosh Proofreader A.Zimokosov

Claims (1)

AUTOMATIC IRRIGATION CONTROL DEVICE, comprising the stabilized power supply unit, a comparison unit with threshold elements, a water supply control unit, as well as a subsoil electrode and ground electrodes connected to the comparison unit, characterized in that, in order to improve the quality of irrigation, the device is equipped with a second subsoil electrode located above the first and connected to the comparison unit through contacts controlled by the water supply control unit. -SU 1230514 A1 FIG. 1 of the entire active soil layer: upper and lower. Drying of the soil corresponds to an increase in resistance between the ground electrode and electrodes. When the resistance reaches a threshold value, a signal is supplied to the water supply control device 2, which turns on irrigation and contacts 7 turn off the upper electrode 6. 10 During the irrigation period, the current passes through the ground electrode 4, the soil and electrode 5, i.e. Only the lower layer of soil is controlled. When it is reduced to the lower threshold 15, a command is issued to stop the water supply and the circuit switches to its initial state. A concrete example is the automatic control system of 20 self-propelled sprinklers depending on the actual soil moisture, which operates in two modes. The first mode provides for the automatic opening of the hydrant 25 to start irrigation. Due to a decrease in the actual soil moisture, its total resistance 28 increases, which leads to an imbalance of the resistance bridge 20-23. The unbalance signal 30 is amplified by the transistor 16 and opens the transistor 17. The relay 8 is activated and contacts 10 turns on the solenoid 12, which mechanically opens the hydrant and switches the electroautomatics into standby mode using contacts 14 and 15. The transistor 18 is blocked by the unbalance signal. Irrigation ceases when the actual moisture content of the soil layer exceeds a predetermined limit. The second mode provides for automatic shutoff of the hydrant to stop irrigation. Due to the increase in actual soil moisture, its total resistance 28 decreases, which leads to an imbalance of the resistance bridge 20-23. The mode imbalance signal is inverse to the first mode. It is amplified by the transistor 18 and opens the transistor t9. Relay 9 is activated and turns on the solenoid 13, which mechanically shuts off the hydrant and switches the electric automatics to standby ⁵⁵ (first) mode using contacts 14 and 15. The transistor 16 is opened by the incoming unbalance signal. Irrigation resumes when