Automatic watering system design

General Data

The area to be watered ≈ 4.5 Ha.

Water consumption rate is 8 l/m2 according to SNiP 2.04.0284 *.

The automated watering system of the territory is hydraulically divided into 57 zones.

Automatic watering control is performed by electronic control unit (24 V IVS).

Solenoid valves PGV (57 pcs.)

DBY couplings (120 pcs) are provided for hermetic connection of electrical valves control cables.

For the installation of electromagnetic valves in the ground, the design provides for the installation of valve ducts "Standard" 57 pcs.

For irrigation of green spaces, the project provides for the installation of watering heads of two types:

• Watering heads of rotary type I20 (320 pcs.);

• INST fan type watering heads (514 pcs.);

• INST rotator type watering heads (286 pcs.);

For manual watering, it is provided to install watering hydrants (52 pcs.) For quick connection of watering hoses.

The designed network of watering water supply is made of PVP polyethylene pipes as per GOST 1859983.

The depth of the watering water supply is 0.4 m from the surface of the earth.

After the end of the irrigation season, the irrigation water supply network is emptied and blown by compressed air (compressor).

The purpose of the project.

The purpose of the project is to create an automatic watering system.

2. Design solutions.

The source of water supply is existing tanks of 1000 m3 each. The pump station Saturn 6 240 10 of ESPA (Spain) is designed as pumping equipment. The design characteristics of the main network are: pressure (P) - 8.5 bar and water flow rate (Q) - up to 25.0 m ³/h. Water is supplied to the tank from the main network.

The scheme of irrigation sectors shows the design irrigation zones, designed taking into account the overlapping by sprinklers, the areas irrigated by them for uniform distribution of water.

The number of zones was defined as the ratio of the total throughput of all sprinklers on the site to the estimated throughput of the source. Taking into account the features of watering the site, 57 watering lines were determined.

The ICC800SS control panel (controller) of HUNTER (USA) monitors the switching on and off of each line using solenoid valves PGV151B (57 pcs.).

In the project, they were chosen as the main watering heads (sprinklers):

• fan type sprinklers INST04CV with various nozzles - for watering lawns in small areas, extending from the ground by 10 cm;

• sprinklers of rotary type I20ADS - for lawn watering in large areas, extending from the ground by 10 cm;

Hydraulic calculation of the system was carried out using a table for hydraulic calculation of water pipes (F.A. Shevelev, A.F. Shevelev). On the basis of the performed calculations, the diameters of the pipelines are determined, which provide the minimum required values ​ ​ of pressure and water flow at the point of connection of each sprinkler.

The pipeline routing diagram shows the location of the pressure pipeline and pipelines along the lines.

The pipeline is made of stabilized low pressure polyethylene, resistant to temperature differences from 50 to + 50 degrees Celsius. Recommended operating pressure up to 6 atmospheres. Pipes are laid at a depth of 3040 cm from the surface of the earth.

Wiring diagram of electric cable KVbShV 4 * 2 mm2 (armoured) is wiring from the controller to each solenoid valve .

3. System Description

Automatic watering system consists of:

• sprinklers (sprinklers);

• For manual watering, installation of watering hydrants (52 pcs.) For quick connection of watering hoses is provided;

• solenoid valves supplying water by signal to sprinklers;

• control panel (CP) - controller controlling solenoid valves;

• mini weather station MWS-FR

The principle of operation of the watering sprinklers of the automatic watering system (see schematic diagram) is that when a signal is received from a pre-programmed controller (control panel) according to a certain watering schedule, an electromagnetic valve of one of the lines opens. Under the influence of pressure in the pressure network, the movable part of the watering head is extended from the ground by 10 cm. After a signal is sent to the valve, it is automatically retracted - upon completion of watering. The choice of this type of sprinkler is due to the distances between planted trees and shrubs, as well as the most effective irrigation of the lawn between them, makeup of the root system, and prevention of damage to their bark by high water jet pressure.

Rotor-type sprinklers operate at an outlet pressure of at least 3.5 bar; fan type, not less than 2.5 bar. The watering heads are grouped (summed up) and combined by the piping system into watering zones, which are switched on at a certain time in turn using a controller programmed to start the system. During the rainfall period, due to the use of a rain sensor, the control network opens, which is automatically closed during the period of absence of the above precipitation. The mini-weather station is installed in open space.

Mini weather station consists of :

• Rain sensor;

• Wind sensor;

• Frost sensor.

Rain sensor.

During the rain period, by using a special Rain Click sensor, the control network opens, which closes automatically during the period of no rain.

Wind sensor.

The wind sensor operates as a switch that interrupts the electrical circuit during intense wind, leading to the irrigation system to the valves with electromagnetic control. This allows the time relay to control the process as scheduled, but at the same time, keep the valves from opening the water flow. As soon as the wind force falls below a certain level, this switch again closes the circuit, allowing normal watering. This is done by the effect of wind on the sensor blades. They approximately gain speed up to 180 rpm and stop. The switch pointers on the top of the sensor body indicate the direction of rotation from the moment of rest. Actuation occurs when the value is about the middle of the rotation speed range .

Frost sensor.

The frost sensor is pre-adjusted and cannot be adjusted. It opens the common grounding circuit, thereby protecting the irrigation system from operation at a temperature of 3 0C and below. At a temperature above 3 0С, it will close this circuit for further normal operation.

Control panel (controller) is used to set the program for watering the section. It controls the opening of solenoid valves. A battery (type "Krona" 9 V) is intended for co-storage of the irrigation program. The controller is installed near the storage tanks. The controller is connected to solenoid valves using an electric cable such as KVBbShV 4 * 2.5 mm2 (armored), laid in one trench with the main pipeline. The cable line enters the room secretly. Solenoid valves, which open the water supply in the line at the command of the controller, have the ability to manually control the irrigation process using a handle installed on the valve. Solenoid valves are grouped into combs and installed in decorative boxes with a cover for access to them. Distribution combs are located in the area near the main pipeline in places accessible for maintenance.

To preserve the system for the winter period, a blowdown unit installed at the point of connection to the water supply source is provided. Given the structural features of the watering heads, it is not possible to drain water from them by gravity. Therefore, the system is emptied by a compressor, the method of sequential blowing of each of the lines. Working air head - 6-8 bar, air supply - not less than 100 l/min.

The lines are purged until the spraying of water from the nozzles of the watering heads stops. Irrigation equipment is not de-mounted.

4. Operation of the system

For trouble-free operation of watering heads, a Filter is provided to prevent ingress of natural contaminants, scale, sand.

The procedure for disconnecting and switching on the irrigation system includes: temporary disconnection, disconnection for the winter and activation of the irrigation system.

Temporary disconnection:

• heavy rains;

• The system interferes with any work on the site;

• due to malfunctioning of the system itself.

To do this, disconnect the controller (see the controller instruction).

Winter outage:

• close the ball valve supplying water to the watering system; wrench-cover ball valves designed to connect the compressor to release pressure in the main pipeline, then back-cover the valves;

• blow the system with air through the blowdown unit;

• disconnect the controller (see the controller instruction).

The watering system should be turned on when the snow has come down and the flood waters have gone.

Actuations of the irrigation system:

• open the ball valve supplying water to the watering system;

• enable the controller (see the controller instruction).

If necessary, set up the desired watering program.

Precautions: The irrigation system is completely autonomous and does not require any care. You must comply with some general requirements that do not imply special knowledge:

• make sure to preserve the system for winter;

• do not subject sprinklers to heavy mechanical loads and shocks;

• during landings and other works related to ground opening - be sure to see piping layout

5. Watering guidelines.

The rate of irrigation of green spaces depends on several factors:

• soil on which plants grow;

• climatic zone;

• Frequency and abundance of precipitation;

• temperature mode.

Below are the average values of plant watering taken from SniP 2.04.0284 * Table 3, page 3

Lawns and flower beds must be watered daily at a rate of 8 liters per square meter. Watering is carried out early in the morning or late in the evening .

Fruit trees are watered at 1015 liters per square meter at the barrel circle.

The number of watering should be taken 1-2 times a day, depending on climatic conditions.

The maximum hourly flow rate of each line is not more than 25.0 m ³/h. The recommended watering time for one zone for rotary sprinklers is 60 minutes, rotators - 50 minutes, fan - 12 minutes.

For convenience, the system provides a line of hydrants, connecting to which the hose can additionally pour plants, wash tracks, machines or connect temporarily installed fountains, etc.

Hydrants are installed on the 90 mm main pipeline with 25 mm diameter in terms of tap power.

6. Power supply.

• Control panel

Low voltage transformer is installed in controller. At the input of the transformer: alternating current with a voltage of 220 V and a frequency of 50 Hz, at your stroke - 24 V with a current intensity of 1.25 A.

• Pump station

Voltage 380 V and power 9.0 kW.