Performance Tests of Microirrigation Filters After Long Term Simulated Use

The following tests are designed to evaluate the performance of a filter after 10000 flushing cycles under the simulated-use conditions. The filters are of automatic flushing strainer-type filters and disc filters for microirrigation in agricultural irrigation systems.

Operate the filter using clean water or a similar type of water (chemically and physically).

Initiate each flushing cycle by appropriate means, to be determined and described by the laboratory.

NOTE: Since the automatic flushing control capability will not be usable in these tests, performance of the flushing control mechanism is not taken into account.

1. Establish the pressure at the filter inlet and maintain it for at least 10 s at the nominal pressure and cause water to flow through the filter at a flow rate approximately equal to the flushing flow rate at the nominal pressure plus 20%.
2. While maintaining the pressure at the filter inlet at not less than the minimum filtering pressure, allow the flushing cycle to terminate without external intervention.

After completion of the 10000 cycles, carry out the following tests.

1. Performance tests

   Carry out the following performance tests:

   • resistance of filter to internal hydrostatic pressure;
   • volume of flushing water and duration of flushing

   The filter shall meet the requirements specified in each of these tests.

2. Visual examination

   Dismantle the filter and examine its internal parts for excessive wear or damage. The parts shall show no damages, such as damage to the filter housing, to moving parts or to the filtering elements, nor any cracks or fractures.

   Damage to moving parts or to the seals, which do not impair the functioning of the filter, shall not be considered as a failure in this test.