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SCREEN CHOICE CAN MAKE THE
DIFFERENCE IN WELL EFFICIENCY
The Johnson Screens, USA is pioneer and World leader in manufacturing of all welded V-wire screens for varieties of applications including Water Tube Wells, Oil & Gas Wells, Mining and other Industrial applications. Johnson has been manufacturing these screens since 1904 and serves World wide market through manufacturing units spread across the World like USA, U.K., Australia, Japan, France Indonesia and now in India.
The Johnson Screens (India) Limited is a Indian joint venture with Johnson USA with complete technological support and all specialized machines from Johnson USA and Australia, manufacturing V-wire screens at their modern manufacturing plant in Gujarat near Ahmedabad.
Unlike slotted strainers,
it is not made by simply putting slots on a blind pipe. Instead, it is
manufactured by a very special, fully computerized process. A continuous profile
wire is spirally wound around series of longitudinal support rods. Each
and every intersection of profile wire and rod is fusion
welded on computerized machine to
impart high strength. The spacing
between two adjacent turns of profile wire is the slot or opening for water to
enter. The profile of the wire is such that its flat surface remains on the
outside dia. of screen to produce inwardly
widening slots.
This way we get a strong screen (due to continuous wire
and fusion welding) with continuous slot of inwardly widening shape.
ADVANTAGES
OF JOHNSON SCREEN
Large
% open area
Due to continuous slots and special design, the Johnson Screen has more than double % open area for water to enter compared to slotted strainer for same slot opening. More open area means lesser Entrance Velocity and lesser Frictional Loss. Even lesser length or small dia. of screens can be used without compromising on total open area.
Better Sand Control
Due to wide range of accurate slots down to 0.25 mm (1/100”) or even lesser in special cases, much better sand control can be achieved without loosing much on open area. Reduced entrance velocity makes the flow more laminar and reduces turbulance, which further improves the sand control.
Lesser sand pumping – Lesser pump maintenance – longer tube well life
Non-clogging Slots
Inwardly widening slots do not allow any particle to get stuck inside the slot and cause clogging. Thus the slots are non-clogging. This ensures no reduction in discharge over a period of time due to clogged slots. This means Longer Effective Life of Tube Well. Moreover, due to reduced entrance velocity the formation of incrustants is also very slow.
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Improved
tube well development
The uniform unobstructed slots allow development air to flow uniformly to all spots of aquifer. This enables better development of aquifer and better gravel arrangement not leaving any Blind Spots. Improved development means higher
discharge and better sand control Reduction in Draw Down – Improved Efficiency – Energy Saving
Efficient Tubewell With Johnson Screens
Appreciable reduced
well losses (frictional losses) reduces the draw down.
This reduces the pumping head which obviously improves the discharge of same pump and reduces energy consumption
considerably.
Thus the efficiency of tube well improves considerably.
proportional to discharge and pumping head as
per following formula:
| Power
consumption = |
Q x
H |
|
102 x
n0 |
Q = Discharge
H=Head n0 =Pump overall efficiency
102 = Conversion factor
Both n0 & 102 are constant factor, hence;
Power Consumption µ Q x H
Hence reduction in pumping head directly reduces the power consumption. Moreover increased discharge from same pump reduces the pumping hours and in turn the power consumption.
Screen with
Different Slot Patterns:
% age of Open
Areas in above Screens:
1.
Johnson Screen - 37 %
2.
Bridge Slot Screen - 12 %
3.
Louvered Screen - 8 %
4.
Slotted Screen - 2.5 %
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