How to...
How to...
service a disc filter
This editorial describes the filtration process as well as the procedure to service a manual disc filter. The procedures have been based on one of the most extensively used manual filters being the Arkal 2 inch Dual model. Other models of filters and especially alternative brands will use different procedures, however the underlying basic maintenance systems
remain the same for all disc filters.- by Mike de Villiers
Filter systems are classified into three types, namely sand filters, mesh / screen filters and disc filters. The filter type, as well as the grade and capacity of the filter, has to be carefully selected dependent on a number of key factors, such as the type of irrigation emitter, water quality, required flow rate as well as the available water source. These decisions are critical to the performance of the entire irrigation scheme and require the services of a suitably qualified and approved designer.
Filtration is an essential function in any micro irrigation system as it prevents the ingress of solids into the system. Filter systems are classified according to varying levels of filtration. Pre-filtration, Primary filtration and Secondary or block filtration. Primary filtration is the most important function, with pre-filtration and block filtration added as required, dependent on water quality and the type of emitters being used.
INTRODUCTION
The process of filtration is to remove unwanted particles from the water supply, which are retained in the filter body and eventually impede the flow rate through the filter. The increase in the pressure required to maintain optimum flow through the filter is the indicator that the filter needs maintenance. Many systems incorporate automated or manual backwashing / back-flushing functions that reverse the water flow through the filter to remove the unwanted debris, whereas less sophisticated filter systems need to be manually dismantled and cleaned as required. Needless to say, factors such as the pump capacity and pressure need to accommodate the flow rate required to achieve backwashing, in addition to the required needs of the irrigation system.
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SABI | FEBRUARY / MARCH 2017