MTech.

The success of micro irrigation depends directly on the ability of the system to
prevent emitter clogging. The major sources of emitter clogging are suspended solids
present in the irrigation water, but this is the easiest problem to solve through
filtration. Various kinds of filters used for filtration of irrigation water include
hydrocyclone filters, screen filters, disk filters and sand media filters. Of these,
hydrocyclone filters are fast process separators using the principle of centrifugal
sedimentation to separate the solid particles that are denser than water.
Hydrocyclones have no moving parts and screens as in the case of other filters.
Tremendous research have been done on the performance evaluation of all other
filters in the field of micro irrigation, but much researches have not been done on the
performance evaluation of hydrocyclone filters. Therefore an attempt had been made
to evaluate the performance of the hydrocyclone filter.
In this study commercially available hydrocyclone filter of size 8" was selected
and the performance of the filter was evaluated with four different known
concentrations, viz. 300, 600, 900 and '1200 mg/I of soil suspension. The experiment
was conducted for each known concentration of soil suspension to determine the
head loss build up, discharge and filtration efficiency at every five minute interval
for ten hours. The performance of the filter was evaluated by analyzing the variation
between elapsed time, pressure drop, discharge, influent concentration, effluent
concentration, filtration efficiency and particle size .distribution of the under flow
material.
First, the clean pressure drop of the filter was evaluated and the percentage error
in the experimental results had been found to be in the range of -4.16 to + 1 O. The
clean pressure drop varies lA to the power of discharge with a R2 of 0.9982.The
maximum and minimum clean pressure drops obtained are 0.52kg/cm2 and
0.14kg/cm2 for nominal flow rate 25m3/h and minimum recommended flow rate 10
m3/h.

The maximum pressure drops obtained for 300, 600, 900 and 1200 mg/l
concentration of soil suspension are 0.42, 0.46, 0.51 and 0.54 kg/cm.' at 350, 390,
280 and 190 min respectively. It was found that there was no much variation in
initial and final pressure drops for all the cases of soil suspension. The empirical
relations between these two parameters for different concentrations of soil
suspensions show good trend with coefficient of determination varying from 0.81 to
0.9.
It was found that the initial discharges for all the four concentrations of soil
suspension are almost the same i.e.5.l3 lps and the final discharges after ten hours of
operation for 300,600,900 and1200 m11 soil suspension are 5.03, 5.08, 5.10 and 5.11
lps respectively. The minimum discharges are found to be 5.05, 5.02, 4.98 and 4.89
lps at maximum pressure drops 0.42, 0.46, 0.51 and 0.54 kg/cm' respectively.
The initial concentrations of the influent of 300, 600, 900 and 1200 mg/l are
found to be 296.3, 597.34, 896.78, and 1190.67 mg/l and the final concentrations
were found to be 69.69, 69.18,91.16 and 122.38 mg/l respectively. The maximum
efficiency of different soil suspension are 30.3, 32.96, 43.89 and 52.5% and the
minimum efficiencies are 9.91, 9.93, 9.62 and 9.9% respectively. It was found that
the final efficiencies are almost the same irrespective of the concentration of soil
suspension.
The particle size distribution of underflow material for different concentrations of
soil suspension indicates a measure of separation efficiency of the filter. It was found
that the percentage finer to coarser particles is almost the same for all the
concentrations but for lower concentrations, fine particles have higher percentage of
finer. This may indicate the efficient separation of fine particles in the case of lower .
concentrations of soil suspensions. For the soil suspension of 300, 600, 900 and
1200mg/1 the percentage of particles finer than 0.075111111 are 0.86, 0.58, 1.96 and
4.05% respectively. The higher value of concentration for 300mg/1 indicates the
better separation of finer particles.