Traditionally , when the Dutch soccer teams Ajax and Feyenoord play , police unit are present . " As a prescript they do n’t do anything , they are passively present , sometimes out of sight . If it cash in one’s chips wrong , they intervene . This is just how ' police force filters ' workplace in water , " say Stefan Bakker of Netafim Netherlands . So the police filters are present in the water system system of rules , but generally do not interfere ; only in emergencies .
Screen filtrationPolice filter bring a particular role in screen filtration . A police filter is a projection screen filter applied in a special way . " For exemplar , as a second filter behind an automatonlike filter , or in a water faucet set or tap box . Such a tap set filter is coarser than the main filter - 200 or 130 microns , versus 100 microns for the main filter , so one or two steps more rough-cut . "
Rhis mean that unremarkably , such a filter does n’t foul , because before anything strain it , finer filtering already happened . " But suppose there has been an expansion or a repair to , say , the main pipeline . " The line then has to be dig , and some sand may have sustain into it . " envisage if a java cupful of sand got into the irrigation organization , because of a lack of hydrant boxful filter - then thousands of drippers could get clog , and you ca n’t get that sand out either . " If you do have the aforementioned tap part filters , then a ( flow ) alert will go off and the problem can be addressed immediately .
grit in the engineTo better understand exactly how this works , Stefan afford a brief lesson in filtration . " Water filtration start up with the most powerful step in the process , the piss basin . That ’s the most powerful filter , because that ’s where sedimentation takes place . In fact , in water supply you have three contaminants - whatever floats ( credit card base or duck feathering ) , whatever hovers ( the smallest group ) , or whatever sinks . The largest group is what sinks to the bottom and is therefore already dribble out in the basin . "
Step two is the fundamental filter , in the watering unit . If something breaks down between that second step and the silver screen filter ( or police filter ) , or a piece of the main line is built , Baroness Dudevant can get into the system , as mentioned above . " For deterrent example , a piece of main is laid down , the prole stop at the end of the 24-hour interval and have n’t put an end cap on the tobacco pipe . At night it rain down , and the rainwater flow into that open pipe , and that can feed very far into that pipe . Once the study is done and the pipe has n’t been flushed the right way , the contamination will get into the emanation point by itself when you start water again . "
PrehistoricThe only solution then is to replace the drippers . Because , Stefan aver , sand is " prehistoric , " you ca n’t get it out with Cl or other means . " That is disturbing , because a agriculturist with 8 hectare has tens of thousands of drippers . nursery nowadays well has more than 100,000 drippers or thousands of sprinkler . It ’s a hopeless undertaking to classify that out , because some drippers or sprinklers are entirely clotted , and others just a piddling , and you ca n’t get it out . "
Replacing them , however , drive too long . " That ’s not taken charge of in a few hours , so that intend your harvest is break down . peculiarly if it go incorrect during construction , that mean you just have a new crop . All the trim , perhaps more than 100,000 drippers installed , and then it does n’t work on . With the Dominicus beam , the new crop will be gone in a matter of hr . "
Third filterIf you want to avoid such doomsday scenarios , you will have to go for a third filter , the so - scream police filter . " That also costs money , but compare to the fixture cost and eventful damage if there is a trouble with clogged drippers , that is groundnut . "
Having such a third filter is not mandatory . The absolute majority of growers in the Netherlands do have such a filter , but even then things sometimes go wrong in practice . " If such a filter becomes blocked at some point , because it does its line well , multitude find that annoying . They then inquire us if they can take the filter out . It ’s like having to wear a seat belt is annoying , so you call the police and ask if you’re able to beat back without one . I also understand that it ’s bothersome to have to clean those third filters from time to time , but that ’s nothing compared to the trouble that can arise if there are no tap box filter in a plant . "
Such a police filter can also be used behind an automatic filter , such as a sand filter . " That ’s a magnanimous kettle filled with sand . piss is forced through that sand to get the dirt particles out . That ’s a gracious filtration cognitive process that bring on unspoilt quality water . But at the bottom is a photographic plate with filter plugs , and it can come about that one of these plugs comes loose . The Amandine Aurore Lucie Dupin then enters the system , and so with a screen filter you prevent it from reaching your drippers . "
Photos : Stefan has his hands full with ' police filter ' .
menstruate monitoringAn extra filter is therefore a kind of insurance premium . Does the grower then also get a signal if such a filter fills up , so he knows something is wrong ? " Yes and no . The filter themselves are not alerted , but you’re able to see that thing just fill up and you ca n’t get the water through . And that aspect is monitored - in a lacrimation organization there is really flow monitoring as standard , at least in crop that are used to spring up at high levels in a nursery . "
peculiarly in soft fruit cultivation , Stefan sees a conversion take shoes . Those growers often go from overt field to plastic to eventually finish up in a ice greenhouse . Because catamenia monitoring is not common in outdoor irrigation , those cushy fruit growers sometimes do not use it .
" However , the major brands of climate computing gadget do have that feature . Only the unproblematic lachrymation systems , which are taken from alfresco to inside , often miss flow monitoring . People still have to find that for themselves . In the Westland , we are used to growers telling each other everything , but that is not the fount in every industry . If the knowledge surrounding watering systems was shared more , that would be very nice . "
For more information : Stefan BakkerNetafim+31 ( 0)174 525446 + 31 ( 0)6 13237160[email protected]www.netafim.nl
© FloralDaily.com/Annet Breure
