The method of automatic control of drip irrigation in the greenhouse and device for its implementation

 

The invention relates to automated control systems for irrigation, particularly drip irrigation nutrient substrate solution (C) boarding vessels (PE) for vegetable crops in the greenhouse. The method of automatic control of drip irrigation in the greenhouse includes the measurement of humidity on the control plot (KU) (s) (PE) plants by broaching is used as the humidity sensor (DV) insulated conductor (PI) through their root layers (COP). Appointment and termination of drip irrigation in achieving soil moisture (C) around (FE) lower and upper bounds takes place simultaneously in the (PE) in all areas of the greenhouse. For averaging humidity (C) (PE) (KU), respectively, and the length (PI) is determined experimentally and calculated by the formulawhere n is the number (PE); G is the standard deviation humidity (NE); Gxgpermissible error of the standard deviation humidity (PE). The device for implementing the method is mounted on (KU) and includes a humidity sensor (DV), the generator, the current meter (it), the transformer (T). (DV) is made of flexible insulated wires with sealing at the ends and RA the secondary winding (T). The primary winding (T) is connected to the generator through (it), the output of which is connected to the threshold block (PB). (IB) is produced from the comparator connected to a second input with potentiometer setting the desired humidity and the output time relay and actuator irrigation installation. The third winding (T) is connected to the feedback circuit to stabilize the voltage amplitude. (LW) - conductor pulling on the control plot through (CC) (PE) for plants. The ratio between the generator and (DV) is determined based on the number (PE) on (KU), and is determined by the formulawhere Knthe transformation ratio (PE) in (LOC); Kithe ratio for one (PE) (RL); n is the number (PE) (KU). The invention provides automatic control of drip irrigation with nutrient solution (S) in (PE), depending on the needs of the plants in cultivation of vegetable crops in the greenhouse. 2 S. and 1 C. p. F.-ly. 1 Il. 2 table.

Patented group of inventions relates to automated control systems for irrigation, particularly drip irrigation nutrient solution substrates in planting containers for growing vegetables in greenhouses. (See The USSR and.with. 1697628, A 01 G 9/02, 1991). In the known method the perforated pipe stretch from the top through the side walls of the planting containers (cups) and connect to the water supply network. In this way, drip irrigation will occur waterlogging of the substrate, and watered with nutrient solution salinity of the substrate. In addition will not need to be spent irrigation water and fertilizers.

There is a method of measuring soil moisture irrigated area (see RF patent 1724113, A 01 G 25/16, 1992). In this way below the topsoil lay an isolated conductor in the gap which connect the generator. The conductor stack zigzagoon increments equal to the thickness of the controlled layer, which is formed briefly closed the line and is a standing wave.

The middle line is the antinode of the current, the maximum of which depends on the phase velocity of the wave, defined dielectric constant of the soil and its moisture content. About the conductor, at the beginning and in the middle of the set of inductive probes with which to determine the ratio of the currents at the beginning of the line and in the field of maximum - the middle line. This ratio serves as a source indicator for determining soil moisture. who at the time of its measurement in irrigated array. However, this method cannot be used in the automatic control system of drip irrigation, because the plots have a heterogeneous composition of the soil, and in this case it is necessary to lay the conductor for the entire irrigated array, and this is uneconomical and practically difficult to implement.

There is a method of automatic control of irrigation, taken as a prototype (see the USSR as.with. 1704710, A 01 G 25/16, 1992). The method involves the measurement of soil moisture at multiple points in the control plot, the appointment and termination of pulse irrigation in the control plot, while achieving humidity at given points of the lower and upper boundaries and the implementation of the single releases water on other parts of the field for a period of time, the duration of which is determined depending on the time of setpoint humidity on the control plot. There is a method of automatic control provides irrigation in areas with irrigation norm that is spent on the control plot. However, the known method due to point humidity measurement due to the heterogeneity of the soil may not give the average humidity in irrigated areas and to provide simultaneously watering at all sites, chetah. A device for implementing this method includes humidity sensors control plot, the threshold evaluation unit humidity, the memory block with the ring and reversible counters for storing the total duration of the impulse irrigation control plot until you get on it the desired humidity. To control the memory block serves as a generator, and switch on irrigation from other areas of the one - shot and logic OR and And, the pulse shaper and counter watered plots and the control unit actuators watering.

The device ensures the implementation of the method of automated control pulse irrigation in the control plot and subsequent irrigation of areas with a one-time release of irrigation norms on them, which is spent on the control plot. However, this device has a multi-channel, sophisticated relationship between the elements and is not intended for simultaneous drip irrigation in all areas.

The closest device to the same destination to the claimed invention on the totality of symptoms is the device controls (see the USSR as.with. 1702970, A 01 G 25/16, 1992). This invention (taken as a prototype of the as humidity sensor, installed in a controlled environment, use a flat capacitor. The capacitor included in the oscillating circuit, which is the load master oscillator with a quartz frequency stabilization. Reducing humidity controlled environment leads to an increase in voltage in the oscillating circuit, which is supplied to the control unit, made in the form of series-connected rectifier, a DC amplifier, the threshold block and relay. Upon reaching the voltage threshold value due to changes in the capacitance of the humidity sensor is triggered, the relay including irrigation installation. Watering takes to recover the initial humidity of the environment. The disadvantage of this device is that it uses as a humidity sensor capacitor holds a small amount of controlled nutrient medium, and therefore is not able to reflect the average humidity of the substrate in a separate landing capacity, especially in boarding vessels throughout the greenhouse.

The technical task of the present invention was to develop automatic control systems drip irrigation nutrient substrate solution in a separate planting containers for vegetable culturalmente bags with slits for planting). Nutrient solution is fed through tubes to the root necks of each plant droppers that are installed on the irrigation pipeline.

The need to develop an automatic control system of drip irrigation nutrient solution due to the fact that peat-based substrate in planting containers has a small volume and has a low buffer capacity, and therefore require frequent drip irrigation and operational control of the humidity of the substrate. In addition, the humidity of the substrate in the areas of greenhouse varies, depending on the homogeneity of the substrate, unequal transpiration rate, pressure difference at the beginning and end of the drip line fault droppers.

The technical result in the implementation of the invention regarding the method and the device was the creation of a reliable system of automatic control of drip irrigation nutrient solution on the basis of averaging the relative humidity of the substrate on the entire surface of the greenhouse.

About the way it is achieved that, in contrast to the prototype (and. C. 1704710) measurement of moisture content of the substrate on the control plot produced in planting containers of plants by pulling insulated conductor through insti substrate of the lower and upper bounds around the insulated conductor carried out simultaneously in planting containers in all areas of the greenhouse, the number of planting containers on the control plot and accordingly the length of the insulated conductor determined experimentally and calculated by the formulas below, based on the amount of variations in the moisture in planting containers.

Use organomineral substrate is homogeneous isolated from each other planting containers for plants, pulling the insulated conductor through their root layers allows you to average the relative humidity of the substrate on the entire area of the greenhouses and to provide irrigation nutrient solution depending on the needs of plants.

Relative to the device it is achieved that, in contrast to the prototype (and.with. 1702970) it is equipped with a current meter and transformer, as well as the humidity sensor substrate in planting containers control plot used an isolated conductor is made of a flexible insulated wires with sealing at the ends and split in the middle part into two beams, one of them connected to the first output and the other to the second terminal of the secondary winding of the transformer and the primary winding of the transformer connected to the generator through the measuring current, the output to the rate specified humidity and exit - with time relay and actuator irrigation installation.

In addition, the transformation ratio is determined by the formulawhere Knthe ratio for landing tanks control plot; K1the ratio for one of the landing capacity of the control area; n is the number of planting containers on the control plot.

Supply device transformer provides the regulation and maintenance of a given level of stress and coordination in the circuit between the generator and three-dimensional extended humidity sensor substrate in planting containers on the control plot.

The supply device by the current meter monitors the amount of current, depending on the moisture content of the substrate in the circuit of the capacitive sensor.

The execution insulated conductor of the flexible insulated wires with sealing at the ends and split in the middle part of the two beam supply current in planting containers and convenience when pulling the conductor through their zone location of the root system of plants. Perform threshold block of the comparator connected to a second input with potentiometer setpoint specified wet the Noah moisture content of the substrate in planting containers on the control plot.

The claimed group of inventions complies with the requirement of unity of invention, since the group runobject inventions form a single inventive concept, one of the declared objects of the group - a device for automatic control of drip irrigation in the greenhouse is intended for carrying out another of the declared object group - method of automatic control of drip irrigation in the greenhouse. Both group object of the invention is directed to solving the same tasks - automatic control of drip irrigation nutrient solution depending on the needs of the plants in cultivation of vegetable crops in greenhouses on nutrient media and substrates. Conducted by the applicant's analysis of the prior art, including searching by the patent and scientific and technical information sources and identify sources that contain information about the equivalents of the claimed group of inventions for object and object-devices, has allowed to establish that the applicant had not discovered analogues as for a method and device of the claimed group, characterized by signs, identical with all the essential features of a method and device of the claimed group of the who as the most similar set of features analogues - helped to identify a set of essential in relation to the above technical result of the distinctive features for each of the stated objects of the invention set forth in the claims.

Thus, each of the objects of invention meets the condition of "novelty". For checking the conformity to each object of the claimed group of inventions is the condition of "inventive step", the applicant conducted an additional search of the known solutions in the patent and scientific and technical information sources. The search results showed that each object of the claimed group of inventions on set of distinctive features is not subject to the known technical solutions and does not follow for the expert in the obvious way from the prior art. The claimed method of automatic control of drip irrigation in the greenhouse enables measurement of the moisture control section of the substrate in planting containers of plants by pulling insulated conductor through their root layers, and the appointment and termination of drip irrigation nutrient solution to achieve the moisture content of the substrate lower and upper bounds can be made simultaneously in boarding emestine length of insulated conductor determined experimentally and calculated by the formulawhere n is the number of planting containers; G is the standard deviation of moisture in planting containers.
Gxgpermissible error of the standard deviation of moisture in planting containers.

When the experiment estimation of the average moisture content of the substrate is carried out by sampling from different planting containers, weighing and drying each sample and averaging the obtained results.

The calculation of the average moisture content Wcp, the standard deviation of G and the error of the mean Gxperformed using well-known formulas (see E. A. Dmitriev. Mathematical statistics in soil science. M.: Izd. MSU, 1995)

where n is the number of planting containers from which samples; Wi- the value of the specific humidity of the sample in one boarding the vessel. The formula (3) can be converted

Formula (4) allows to determine the required number of planting containers n for the calculation of the average moisture content of the error has not gone beyond the limits of permissible errorsx=Gxgthat is given technological conditions depending on the biological characteristics of the crop.

Below is experimentalphysik 35 planting containers, greenhouses, humidity was determined thermostatic-weight method in percentage to the lowest capacity (LC). The value of HB peat substrate was 590 wt.%. The results are presented in table. 1.

From the obtained number of planting containers have been made by grouping 3, 5, 10, 15, 20, 25, 30, 35. For each group was determined by the average humidity Wcp, the standard deviation of G and the error of the mean Gx.

The results are shown in table. 2.

The results showed that the minimum humidity value in boarding the vessel was 69,2%, and the maximum and 82.2%, the difference was 13%. When averaged humidity standard deviation of G does not exceed 3%. Error of the mean Gxdeviation decreased with increasing number of planting containers and 10 was less than 1%, which is quite satisfied with the culture of pepper.

The device for implementing the method of automatic control of drip irrigation in the greenhouse is shown in block diagram. The device is mounted on the control plot and includes the humidity sensor 1, the generator 2, the current meter 3, a transformer 4. The humidity sensor is made of a flexible insulated wires with sealing at the ends and split in the middle part of the two beam 5. One of them is connected to the ground is glucina to the generator through a current meter, the output of which is connected to the threshold block. The threshold block is made from comparator 8 is connected to a second input with potentiometer 9 setting the desired humidity and the output time relay 10 and actuator 11 irrigation installation. The third winding 12 of the transformer is connected to the feedback circuit 13, stabilizing the amplitude of the voltage. Humidity sensor - conductor pulling on the control section through the root zone layers planting containers 14 for plants. The ratio between the generator and the humidity sensor determines, based on the number of planting containers on the control plot.

More than the required number of planting containers n, the greater the length and capacity of the sensor and less capacitive reactance xc=l/2fC. When the number of planting containers n should agree generator with sensor. The agreement is in constant load on the generator and permanence supplied to the load power.

Consider two sensors and one boarding capacity and b) with a number of planting containers.

Load power:
a) Pa=Ua2/Xa; b) Pn=Un2/XnPa=PnU1and the coefficients of transformation To aandand Kn:
Ua=U1/KaUn=U1/Kn,
Pa=U12/Ka2Xa=U12/Kn2Xn=Pn,
since Pa=Pn1/Ka2Xa=1/Kn2XnKn2=Ka2(Xa/Xn)=Ka2n
Since the resistance of the sensor is inversely proportional to the number of seats n finally, i.e., the transformation ratio is proportional to the square root of the number of seats
The device operates as follows.

High-frequency voltage generator 2 through the current meter 3 is fed to the primary obmenu 4 of the transformer. On the secondary winding 6 is induced low voltage U2: U2=U1/Knwhere Knthe transformation ratio.

The voltage U2served on bundles of conductors 5 of the probe 1 humidity, capacitive current flows from the conductors of one beam to the other conductors, partially through the insulation of the conductors and partially through the surrounding substrate. The first component is constant in magnitude, and the second depends on the humidity of the substrate. Emcause reflects the average humidity in planting containers. Its value is determined by the expression
J2=U22FC
where f is the frequency; C is the total capacity of all sections of the sensor 1.

In the primary winding 7 there is a current J1I , J1=J2/Kn=U22fC/Kn=U12fC/Kn2
In the primary winding 7 also flows inductive magnetizing current of the transformer core 4 -:=U1/2fL1where L1the inductance of the primary winding 7. In addition, in the primary winding 7 current flows Ja- current active losses in the core and windings of the transformer 4, the substrate and the conductor of the sensor 1.

The amount of current losses of Jait is difficult to calculate, but its influence can be reduced by introducing feedback 13 to maintain a constant amplitude of the voltage on the transformer. The resulting current 1 circuit current meter 3 is determined by the vector summation of the three components of currentsThe first component is predominant over the other.


When postans the indicator of the current 3 in the form of a DC voltage, proportional to the current J1goes to the first input of the comparator 8, the second comparator input voltage from the potentiometer setpoint 9. Desiccation of the substrate capacitive current decreases, the current J1and the output signal of the measuring current 3. If it falls below a preset voltage level set point, remove from the potentiometer 9, enables the comparator 8, time relay 10, the actuator 11 and begins drip irrigation in planting containers on the entire area. As the wetting of the substrate on the control plot increased capacitive current and the output signal of the measuring current. When he reaches the level of the setpoint potentiometer 9, the comparator will turn off, but irrigation will continue for some time determined by the exposure time relay 10. Practice has shown that the glaze on the sensor signal 1 without time relay 10 occur too frequently in small doses, that adversely affects the operation of irrigation equipment.

When growing removable vegetable crops in planting containers greenhouses process automatic control drip irrigation repeat a similar way as with the culture of pepper. Determine experimentally the control plot the number of pagnotti substrate on the entire surface of the greenhouse was less than the allowable value of moisture, based on the biological characteristics of a given culture. Then, in accordance with the number of planting containers 14 on the control section determines the transformation ratio in the circuit between the humidity sensor 1 and the generator 2. Next, measure the moisture content of the substrate in planting containers are produced automatically only on the control plot, and the beginning and the end of the drip irrigation nutrient solution is performed simultaneously in planting containers in all areas of the greenhouse.


Claims

1. The method of automatic control of drip irrigation in the greenhouse, including the measurement of the soil moisture sensor on the control plot, purpose and end of irrigation when reaching the soil moisture control section, the lower and upper bounds and subsequent irrigation plots with irrigation rate, which is the control section, wherein the control plot measure the moisture content of the substrate in planting containers of plants by pulling used as a soil moisture sensor and connected to irrigation installation of insulated conductor through the root zone layers of plants, and the appointment and termination of drip irrigation, piratea carried out simultaneously in planting containers in all areas of the greenhouse, the number of planting containers on the control plot and accordingly the length of the insulated conductor determined experimentally and calculated by the formula

where n is the number of planting containers;

G - mean-square deviation of the moisture in planting containers.

Gxgpermissible error of the standard deviation of moisture in planting containers.

2. Device for automatic control of drip irrigation in a greenhouse, comprising a humidity sensor connected to the generator, the threshold unit and relay include sprinkler system, characterized in that it is equipped with a current meter and transformer, as well as the humidity sensor substrate in planting containers control plot used an isolated conductor is made of a flexible insulated wires with hermetically at the ends and split in the middle part into two beams, one of which is connected to the first output and the other to the second terminal of the secondary winding of the transformer and the primary winding of the transformer connected to the generator through a current meter, the output of which is connected to a threshold unit, made from the comparator, ilen mechanism irrigation installation.

3. The device according to p. 2, wherein the ratio is determined by the formula

where Knthe ratio for landing tanks control plot;

Kithe ratio for one of the landing capacity of the control section;

n is the number of planting containers on the control plot.

 

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