滴水灌溉系统-城市园林绿地规划(英)课件

1、Drip IrrigationBest to find out what the water pressure is in your building.Fit a pressure gauge to the isolation valve. Pressure should be about 60 to 75 psiBackflow PreventerPrevents dirt, salmonella, etc from being sucked back into drinking water system.ImportantAlways use backflow preventer on e

2、very drip systemPressure Regulators and Pressure Reducing ValvesYou will need to install a pressure regulator on your drip system if your water pressure is higher than 2,8 bars (40 PSI). Types of filtersScreen FilterMost CommonCheapExcellent for removing hard particulates from water, such as sandMed

3、ia FilterBest for removing organic material from the waterCentrifugal FiltersAlso known as sand separators, centrifugal filters are primarily for removing particulates, such as sand, from the waterDisk FiltersDisk filters are a cross between a screen filter and a media filter, with many of the advan

4、tages of both. Disk filters are good at removing both particulates, like sand, and organic matterWater Source withSuggested Filter TypesMunicipal Water SystemScreen Filter, Centrifugal Filter, or Disk Filter.WellScreen Filter, Centrifugal Filter, or Disk Filter.River or CreekDisk Filter, Media Filte

5、r and Screen Filter, Centrifugal and Media Filter.Pond or LakeDisk Filter, Media Filter and Screen Filter, Centrifugal and Media Filter.Spring or Artesian WellScreen Filter, Centrifugal Filter, or Disk Filter.Organic material in waterDisk Filter, Media Filter and Screen Filter, Centrifugal and Media

6、 Filter.Sand in waterScreen Filter, Centrifugal Filter, or Disk Filter.Zone control ValvesStandard Globe ValveGlove valves are available in just about any size Anti-siphon valve Available only in 20mm (3/4 inch) and 25mm (1 inch) sizesThe anti-siphon valve MUST be installed above ground and MUST be

7、at least 150mm (6) higher than the highest drip emitter. Drip Irrigation Emitters Short-Path Emitters Advantages: best emitters for very low pressure systems. Disadvantages: They clog up easily. Tortuous-Path or Turbulent-Flow Emitters Advantages: Less likely to clog up, simple, cheap, and work well

8、. Vortex Emitters Advantages: vortex emitters are small in size (about the size of a large pea) and very inexpensive! Disadvantage- because they have small holes they clog up easily, especially if you have hard water (ie; lots of minerals in the water.) Diaphragm Emitters These emitters all use some

9、 type of flexible diaphragm to reduce the flow and pressure,and are much more accurate in controlling the flow and pressure than the previous types. Test to Determine Horizontal Water MovementSmall pin hole in base of bottlePlace in centre of test area, and repeat three timesWait 12 hrs for water to

10、 travel through soilDig three or four shallow trenches about 25mm to 50mm deep (1-2 inches) starting at the centre and extending in different directions toward the edge of the test areaMeasure how far from the centre the soil is moist in the bottom of each trench.Average the total lengths you measur

11、ed to determine how far the water will soak sideways in your soil. Calculating Emitter SpacingOnce you know how far the water will soak horizontally in the soil you can determine an optimal emitter spacing. Just multiply the distance the water moved by 1.9 to get the spacing distance. Using 1.9 rath

12、er than 2 allows a slight overlap of the wet areas. So if you find the water moves 525mm in the soil you would multiply 525 x 1.9 to give a optimal spacing of 1000mm or 1 meter (36 inches).Typical spacing of 4 lph (1 gph) emitters:Coarse soil (sand): 60cm (24 inches)Medium soil: 1.0m (36 inches)Fine

13、 soil (clay): 1.3m (48 inches)Typical spacing of 2 lph (0.5 gph) emitters:Coarse soil (sand): 30cm (12 inches)Medium soil: 60cm (24 inches)Fine soil (clay): 1.0m (36 inches)Drip Systems for Slopes and HillsidesType of Emitters to Use:When installing drip irrigation on a slope or hill side, it is best to use pressure compensating emitters.Drip Tube Orientation:One trick for installing drip systems on slopes is to try as much as possible to keep the drip tubes running horizontal to the slope direction.A