Perforated liner is manufactured by multi spindle drill presses. It is deburred internally and externally, and every hole is visually inspected to make sure all burrs are cleaned up according to API standards.

Perforated casing is often used as base pipe for wire wrapped screen, pre packed wire wrapped screen & . Hose sizes, patterns and pitches (hose spacing) can be customized.

Hole sizes
Standard hole sizes: 9.5mm, 13mm, 14mm, 16mm, 19mm and 25mm. Other hole diameters are available.

Hole Pattern
Holes can be staggered or in straight line as the following pictures from fig 1 to fig 3. Holes are commonly arranged in spiral shape. Straight line is possible.

Pitches
Pitches can be 1" , 2" , 3" , 4" , 6" or 12" . 2" , 3" and 6" are recommended.

How to work out open area of perforated liner?
Open area will influence production and sand filtration. It is determined by hole diameter, the number of holes and the diameter of the liner. The following formula will tell you how to calculate the open area.

N refers to the number of holes per foot.
D refers to the outside diameter of the liner in inches.
C refers to the required open area (percent of surface area).
d refers to the diameter of hole in inches.