Common problems in the design of sprinkler irrigation system

Sprinkler irrigation systems often have some problems in practical application, which are analyzed as follows:

First, the nozzle layout and selection is unreasonable

1. Sprinkler spacing is too long. Without considering the influence of wind speed and water pressure, uneven spraying or even leakage occurs. This is one of the most common factors that lead to the failure of sprinkler irrigation projects. The influence of spray radius, wind speed and water pressure should be fully considered in design, and the spacing of sprinklers should be arranged instead of simply saving the number of sprinklers.

2. The nozzle does not match the pressure and flow of the water source. The pressure and flow of water source cannot meet the requirements of nozzle. When selecting nozzles, the selected nozzles should meet the requirements of on-site water supply pressure and flow, so as to meet the expected spraying effect.

3. Sprinklers do not match terrain and soil types. In small area lawn, choose long-distance sprinkler, in slope, soil permeability is poor, choose sprinkler with high sprinkler intensity, when spraying runoff, resulting in waste of water resources.

4. Sprinklers do not match the site of use. In the sports field, ordinary nozzles are selected, which are not resistant to trampling. In the landscape lawn, swing arm sprinkler or micro-spray is selected to affect the landscape. In the nozzle selection should be based on the use of special nozzle site selection.

5. Nozzle selection is unreasonable. 360℃ sprinkler and fan sprinkler choose the same nozzle, sprinkler intensity is different, resulting in uneven spraying. In addition, standard elevation nozzles are selected where wind speeds are high, so as to increase water drift.

Second, the material selection is unreasonable

Pipe material accounts for a large proportion in sprinkler irrigation engineering material cost, so accurate hydraulic calculation, reasonable selection of material and pipe diameter can not only ensure the system function, but also reduce unnecessary expenses and reduce project cost.

1. PVC material is recommended. When selecting materials, performance, quality, price and construction difficulty should be considered comprehensively. Cast iron pipe inner wall is not smooth, head loss, easy to rust, blockage, construction difficulty. PVC, PP-R and ABS and other new plastic pipes have smooth inner walls, small head loss, no rust, and

Work is simple. However, pp-R and ABS have high costs and are somewhat wasteful for general water supply pipes. PVC is recommended.

2. Too small pipe diameter, large pipe head loss, insufficient nozzle pressure at the end.

3. The pipe diameter is too large, the cost of the pipe network system increases rapidly, causing unnecessary waste of funds.

III. Pressure and flow mismatch with sprinkler system

1. Pressure's too low. Sprinkler can not or working radius is too short, in the form of water column, uneven spraying, leakage, which is the most common factors leading to sprinkler engineering failure. The main reasons for this situation are: insufficient water pressure, lack of pressure device or pressure device is too small, the pipeline head loss is too large, or the terrain is high and the pressure is low.

2. Pressure's too high. High water pressure, large pump selection or high pressure at low places when the terrain fluctuates greatly will overload the nozzle, affect the nozzle life, and even directly lead to nozzle fracture or damage to the gear drive system.

3. Insufficient flow. Spray nozzle can not work or spray between the working radius is too short, the pump can not work under normal conditions. During sprinkler irrigation design, accurate water source data (including pressure, flow rate and influence of water consumption peak period on sprinkler irrigation system flow rate, etc.) should be collected, and correct sprinkler type selection and rotation irrigation group division should be carried out in combination with water source data to ensure that water source flow rate can meet the requirements of rotation irrigation group. Make correct hydraulic calculation, select appropriate pipe diameter, install necessary pressurization equipment or decompression equipment, and ensure that the nozzle works within the normal pressure range.

IV. Lack of filtration equipment or unreasonable selection

Besides matching the pressure and flow of water source with the system, the quality of water is also a factor that designers must consider, and poor filtration is also an important factor that leads to the failure of sprinkler irrigation projects. For sprinkler irrigation system, if the water quality is not good, it may cause nozzle blockage and affect the service life of nozzle and pump. Micro-sprinkler irrigation system has higher requirements for filtration. If the water quality is not good, it may even cause the whole system to collapse, because the emitter flow rate of micro-sprinkler irrigation system is low and the flow channel is complex, once blocked, it is difficult to repair.