IBO STING - Pump Installation Guidelines; Borehole Diameter Requirements; Filter Placement and Dry Run Prevention

19
Lowering the pump in the borehole with a protective strip may
damage the cable insulation. This may damage the pump or cause
electric shock to the operator.
Since the motor needs cooling during operation, the diameter of the
borehole where the pump is working may not be greater than the value
given below in the table of diameters. The values are given in mm. These diameters
depend on the working
capacity of a given pump and dimension of pump.
Working capacity
Type of pump
1 m
3
/h =
17 l/min
2 m
3
/h =
33 l/min
3 m
3
/h =
50 l/min
4 m
3
/h =
67 l/min
5 m
3
/h =
83 l/min
7 m
3
/h =
117 l/min
10 m
3
/h
= 167 l/min
15 m
3
/h
= 250 l/min
20 m
3
/h =
333 l/min
25 m
3
/h =
416 l/min
76mm size
101mm
121
mm
138
mm
90mm size
109
mm
128
mm
144
mm
98mm size
114
mm
132
mm
148
mm
162
mm
175
mm
199
mm
230
mm
274
mm
312
mm
345
mm
Using the pump in a well of a diameter greater than the
one given in the table might overheat and damage the
motor. If the diameter of the well where the pump is to be working is
greater than the diameter given in the table, the pump must be
installed in a special coat which enforces proper cooling. The
concept of the coat has been shown in the figure.
The pump must be installed above the filter of the well.
The minimal
distance between the upper edge of the last part of the filter
and the lower
edge of the motor may not be less than 30 cm.
The pump may not dry run, without water. Dry run damages the
equipment. In this case the repair may be performed only against payment.
To prevent potential dry run the pump must be installed at such depth so that the
lowest dynamic level of the water (water level established during continuous pumping
at free outflow) is at least 2 m above the liquid feed port of the pump.
If the efficiency of the well prevents such assembly (the well is not as efficient as the
pump) then choose an option from the following:
- install smaller pump
- install a valve for constant reduction of the flow on the delivery pipeline,
- install a safety device against dry run to control the level of water table and in
case of dry run to cut off the power supply to the unit.