Center tube has high precision perforated tube with standard oil and glove tubes. The spiral perforating form of the center tube reduces the opening area of the tube cross section and maintains the strength of the center tube to the maximum. The sand is blocked outside of the perforated screen while the oil, gas or water goes through the perforated opening then enters into the screen.

Perforated seam is welded in straight line; with unique spiral distribution formed by spiral welding and greater filter strength. When squeezed in some parts from external, under outside pressure, the forced part will have reduced or closed gap and ensures the reliability of sand control. Made with sophisticated technology, stainless steel filter glove has openings in the side with reduced direct corrosion to the perforated welded sand pipe. Seam gap in the processing ranges between 20 mm-0.7mm. The uniform opening ensures the processing difference is within the error scope allowed - 0.015 mm, also ensures the accuracy of its filter requirements. Using high precision perforating technology, the effective slotting length is the three to five times of common cut seam tube and two to three times of common perforated seam tubes.