START-UP DRIP IRRIGATION SYSTEM

Transcription

1 START-UP DRIP IRRIGATION SYSTEM CHECK LIST Erick Smith, Dari Chavez, Tim Clng, and Lenny Wells, UGA Department f Hrticulture Wesley Prter, UGA Department f Crp and Sil Sciences Specialty crps such as fruits, nuts, and vegetables require irrigatin t prduce high quality crps. Hwever, irrigatin systems are rarely run cntinuusly, and systems idle between crp rtatins, seasns, and/r during maintenance. Any time equipment remains idle and expsed t elements like weather extremes, critters, and ther unfreseen maladies, there is significant ptential fr damage t the system. Perfrming a thrugh preventative maintenance check befre starting the irrigatin system will identify whether the system has been cmprmised and prvide an pprtunity t crrect prblems befre the system is in demand. Drip irrigatin systems are a ppular way t supply plants with water and are usually used t add fertilizers, pesticides, and, in the case f acidic-sil-lving plants like blueberries, acid. Delivering bth water and chemicals thrugh a single system is called "chemigatin." A drip irrigatin system includes a water surce (surface r well), pwer unit, pump, back-flw regulatr (preventer), filter, pressure gauges, pressure regulatrs, flw meter, valves, cnnectrs, pipe, tanks, injectrs, and drip tube (Figure 1). Befre starting the system, perfrm checks and repairs t ensure that the delivery system is in ptimal cnditin. The fllwing are suggestins that will guide yu thrugh a startup maintenance prgram fr yur drip irrigatin system. Figure 1. Typical cmpnents f a drip irrigatin system.

2 Start-Up Check List: Pwer units Pwer units are the prime mvers fr pumps. Maintenance shuld be perfrmed whether the pwer unit is a cmbustin engine r an electrical mtr. Fr cmbustin engines, change the il, install new air, fuel, and il filters, inspect the engine, check fuel lines fr leaks and deteriratin, remve critter nests and ther debris, replace damaged wires, grease drive shafts and service pints, and service the clant system. Fr gas engines, check, clean, and/r change spark plugs. Fr electric mtrs, check the blts securing the electric mtr, remve any debris arund the mtr, ensure that pump packing is in gd cnditin, and check wires fr fraying, cracking, and/r pest damage. Always fllw the manufacturer s recmmendatins fr any rutine maintenance. Pumping systems Fr centrifugal pumping systems (Figure 2), check fr leaks, ensure that the pump turns freely and the gaskets seal prperly, verify that the pump and piping is prperly supprted, lubricate where necessary, and check fr any premature signs f deteriratin, wear, r seizing f cmpnents. Fr turbine pumping systems (Figure 3), check the lubricatin system and service as needed, ensure that the discharge piping is firmly supprted and securely blted, and maintain the packing if applicable. If using a submersible mtr and pump, it is critical that the static level and drawdwn in the well is mnitred. Figure 2. Centrifugal pumps can be attached t either an electrical r mechanical prime mver (Diagram frm Figure 3. Turbine pump assembly with electrical mtr. UGA Cperative Extensin Circular 1093 Start-Up Drip Irrigatin System Check List 2

3 Suctin (intake) lines (fr surface water) Verify that the intake line and screen are clear, that the intake line is prperly supprted, and check fr and fix any leaks. If pssible, pull the pipe ut f the water and check n the cnditin f all suctin cmpnents. Intakes shuld nt be psitined at the bttm f a pnd, as they can pick up debris r plant pathgens that survive in the mud at the bttm f a pnd. Piping and drains Clse all manual pump statin drains, verify that cntrl valves are wrking prperly, and inspect abvegrund pipes, gaskets, and seals. Electrical systems ELECTRICITY KILLS. Use prper safety prcedures when checking these systems. Generally, electrical pumps fr irrigatin are run with alternating current (AC) at 60 Hz (cycles per secnd). Fr greater water demand vltages as high as 480 vlts three-phase electrical pwer surces are used t run mtrs. The ampere (amp) is a measure f energy r electricity mving (current) thrugh the line. It is the ampere that makes muscles cntract, causing the hand t grab n t a live electrical line and nt let g. At 30 milliamps being pushed at 60 cycles, sustained cntact can cause tissue damage and lead t ventricular fibrillatin, heart attack, r death. Gd safety practices include using a lck-ut/tag-ut system, keeping systems prperly grunded, and maintaining a prperly functining multimeter. When first handling electrical fixtures, fill ut tags, put lcks n the breakers, wear rubber sled shes, and remember that the first item t enter a fixture, service bx, r cntrller shuld be the prbes f the vlt meter t check if any f the lines are ht. Once this is dne, inspect and replace all damaged wires. Then tighten all cntacts. Resistance, which is measured in hms, results in heat. As metal heats and cls, cntacts lsen and create greater resistance. This increased resistance can cause fuses t blw and breakers t trip. Lk fr signs f burns, water leaks, and wear n individual cmpnents. In the field Remember ne rule f thumb fr handling electrical fixtures: NEVER GRAB A FIXTURE WITH YOUR PALM DOWN. Use the back f yur bare hand. If the fixture is charged, the natural muscle cntractin will cause yur hand t pull away frm the fixture instead f grabbing it. If yu are unsure abut any part f the electrical inspectin, CALL A LICENSED ELECTRICIAN! Inspect the znes, check valves fr prper peratin, and inspect air valves, which smetimes have critters nesting in them. Identify and replace any damaged cmpnents. If the drip line is sub-surface r under mulch, thrughly inspect the rws fr signs f critter mvement. Fr example, deer may tear the drip line with their hves, cytes may chew n the drip line, and mice may nibble plastic parts. When yu ve identified damage, use flagging t mark the spt, and when charging the system, return t the flagged spt t see if leaks have ccurred. UGA Cperative Extensin Circular 1093 Start-Up Drip Irrigatin System Check List 3

4 Operatinal Check List: Turn n the system. Pressure Verify prper pressure readings at the pump and acrss the filter (Figures 4 and 5). A pressure drp acrss the filter indicates that the filter needs t be cleaned. Check flw meter fr prper peratin (see flw rate calculatin). After checking the pressure regulatr, check the pressure gauge t ensure that the pressure des nt exceed the manufacturer s recmmended specificatins fr the drip line, usually arund 10 psi. If the pressure level lks gd, run the system with the field drains pen and the ends f the drip lines pen. After an adequate amunt f water has flwed thrugh the system, clse the field drains t allw water t mve thrugh the drip lines, and check each drip line fr utflw. Lines with n flw culd be severed, kinked, and/r clgged, and repairs are necessary. Clse up the system and test each blck. Travel the length f each drip line lking fr leaks. T reduce unwanted trips, carry a repair kit with drip line cuplers, extra tubing, a shvel, tls, and a razr knife. T make straight cuts that enable the cuplers t seal, carry a 6- t 12-inch piece f 2x4 and make cuts t the drip line n it. If an extra trip is necessary, place flagging at the spt yu left ff s it is easier t find when yu return. Figure 4. Filter, gauges, and air relief valve. Nte flw meter in fregrund. Nte: if using flagging, remve it after yu are finished with yur task t alleviate cnfusin. Use a cde system with different clrs r patterns t separate tasks. Fr example, use range flagging n blck x fr drip line repair n date x, and use blue flagging t mark the rw yu are presently wrking n. All related flagging shuld be remved when the task is cmplete. Figure 5. Sand that accumulates in disk filters can negatively impact filtering capacity and perfrmance. UGA Cperative Extensin Circular 1093 Start-Up Drip Irrigatin System Check List 4

5 System flw T ensure that the system has nt been clgged with salts during the winter, it is useful t d a quick estimate f the system flw. All drip tape r emitters cme with a standard flw rate at a specific pressure. A cmmn drip tape flw rate might be 0.38-gal/min/100 ft at 8 psi. In an irrigatin blck with apprximately 145,000 linear bed feet, yur irrigatin system shuld be using rughly 551 gallns per minute. If yur flw rate is significantly lwer than the cmmn flw rate, yu may have a large number f clgged emitters. Cnversely, if yur flw rate greatly exceeds yur estimate, yu might have a large number f leaks. Acids can be used t remve scaling and salt buildup frm drip systems. FLOW RATE CALCULATION FOR A ZONE: Example: emitter flw rate at 8 psi = 0.38 gal/min/100 ft Linear bed feet r drip line length in the zne = 145,000 ft 0.38 gal 145,000 ft = 551 gal min 100 ft min Chemigatin System Start-Up Check List: Chemical injectin systems are available in simple t sphisticated systems that apply exact amunts f prduct. Hwever, they all need maintenance and a thrugh inspectin befre peratin. If injecting acid, use extreme cautin when wrking with the system, and wear a face shield, acid-resistant rubber glves, and an acid-resistant aprn. In additin, have an eyewash and safety shwer immediately accessible. Even when wrking n a nn-acid injectin system, the prper prtective gear shuld be used t prevent expsure t the prducts being injected. The persnal prtective equipment (PPE) is listed n the label f the prduct and is a functin f the prduct s chemistry. Always use the highest level f PPE recmmended frm the label t minimize the risk f expsure. Remember that the injectin system has the mst cncentrated frmula passing thrugh it! Venturi injectrs (Figure 6) Inspect the cnnectins, suctin line, valves, venturi injectr, and filter at the end f the suctin line. Replace as needed. If the system has been left ut thrugh the winter, clsely inspect it fr weathering, cracks, and any ther damage. Befre using the injectr, test it with water. Place the suctin line (with filter attached) in a bucket f water. Run the irrigatin system, and nte hw lng a knwn amunt f water is being drawn int the irrigatin system at different settings. Nting the line pressure and drawdwn time can be used t calibrate the system. While the suctin line is in the bucket, shut ff the valves t the injectr. If the system is still drawing r backflushing water, replace the valves. Figure 6. Fittings n the venturi injectr, usually made f plastic, shuld be inspected fr weathering. UGA Cperative Extensin Circular 1093 Start-Up Drip Irrigatin System Check List 5

6 Mechanical pumps Use the manufacturer's recmmendatins fr servicing yur unit. Inspect and clean arund the unit. Lk fr cracks, weathering, and dirt, and replace and clean where necessary. Inspect the valves and cuplers frm the feed tanks t the pump. In Figure 7, a variable in-line flw meter is being used fr chemigatin. The manufacturer s website prvides technical data sheets with recmmended maintenance fr each f its mdels. Like the venturi injectrs, use water t test fr leaks and peratin f the mechanical injectrs, and calibrate t ensure that the crrect prprtins are being delivered t yur plants. Figure 7. Centrifuge pump with electric mtr and a Blue-White variable in-line flw meter. extensin.uga.edu Circular 1093 August 2016 Published by the University f Gergia in cperatin with Frt Valley State University, the U.S. Department f Agriculture, and cunties f the state. Fr mre infrmatin, cntact yur lcal UGA Cperative Extensin ffice. The University f Gergia is cmmitted t principles f equal pprtunity and affirmative actin.