Slot shape and size

The use of 'V' wire in fabrication of screen results in inwardly widening slots. The very shape of the slot in 'V' wire screen presents many advantages over the conventional slotted pipes or even round wire wound screens. In the slotted pipes the chances of blockage of the slots is highest during development process. The sand or gravel grains smaller or equal to size of the slot enter the slot and try to enter the inside of screen against very high friction resistance. In most case they remain lodged in the slot and then still smaller particles tend to get lodged there till the entire slot gets blocked with silt and clay particles. Similar is the situation with round wire wound screens.

Shape of Slots

The slot of the Star water well screens is unique in shape. The inwardly widening shape from the very edge of the slot allows only two point contact with any grain outside it. If the grain size is even marginally smaller, it slips in without facing any resistance and is then removed out of the well with the water. The larger grains remain outside. It is for this reason that Star Water Well Screens are known to be non clogging type. They allow the water to pass freely into the well with least friction.

Coupling with other Pipes

Both ends of the screen are provided with threaded rings, welded to the vertical support rods for easy coupling with other pipes.

Hydraulic Efficiency of Screens

It is an established fact that in most aquifers, the ground water flow is nearly horizontal. The orientation of the slots in the Star Water Well Screens are also horizontal. Thus flow of water from the aquifer into the screens present minimal resistance of the water flow, the flow remains non turbulent (laminar) and hence loss of head is minimal. In addition the continuous slot on star screens has clean the configuration of the slot is Designed to give high efficiency to the well. In other worlds the draw down due to well loss is minimized and the well yield high discharge at low draw down.

Open Area of the Star Screens

The percent open area of the screen is ratio of the voids to solid part of the screen higher the percent open area means higher total open area per meter length of the screen. More the open area available for the water to flow into the well lower will be the entrance velocity and hence lower the head loss. The star water well screens have highest possible percent of open area as compared to there screens. Whereas the slotted pipes have the least open area (10-15 %) the 'V' wire wound screens have highest possible open area (14-50 %) without compromising on structural strength of the screen.

Collapse and Tensile Strengths of the Star Screens

The constructional components of a continuous slot screen are selected to withstand the major stresses on the screens during construction and use of the well the column and the tensile strength required during well construction is provided by the longitudinal rods. The shape and massiveness of the wrapping wire provide the necessary collapse resistance needed during development and long term use of the well.

Material of Construction

The Screen shall be made from wires of either of the following materials :

(a) Low Carbon Galvanized (LCG) Steel (See IS 280)

(b) Stainless Steel SS-304 (See IS 6528)

The screens are classified as regular and heavy depending on well depth.