Water Well Screens: Why Wedge Wire Beats Slotted Pipe | ERQI WIRE

A slotted casing looks like the obvious answer: cut some gaps in a pipe, run it in the hole. The problem shows up when you compare open area at working slot sizes. Cut a 0.5 mm slot through a standard pipe wall and the wall thickness is fighting you — open area on slotted pipe commonly lands between two and five percent of the surface. A wire-wrap screen of the same diameter and slot regularly reaches several times that, which is the difference between the well breathing and the well gasping.

Open area is not a spec-sheet vanity. It decides how much flow a given screen length can collect and how gently the water enters. Low open area forces high entrance velocity, and high entrance velocity is what pulls sand into the pump.

Why the slot stays open for years

The V-profile wire wraps a cage of support rods, point outward. The slot is narrow at the formation face and widens inward, so a grain that enters keeps moving — it cannot lodge at the surface the way it does against the parallel walls of a cut slot. Over years of pumping and backwashing, that geometry is the difference between a screen that cleans and a screen that slowly chokes.

Setting the slot from the sand, not the catalogue

Sieve the formation sample, find the size that half the sample passes, and set the slot to retain the coarse fraction while the fines are pumped out during development. Most wells land between 0.5 and 1.5 mm, but the number should come from the sieve analysis, not from habit — the slot arithmetic is the same as any screen, covered in how to calculate a wedge wire slot.

Material and what actually ends a screen's life

Wear is rarely the killer; corrosion and encrustation are. 304 covers many potable jobs, and 316L earns its premium wherever chlorides run high. Collector and intake duty often runs as flat panels instead of tubes — those are on the wedge wire screen panel page. Sections and sizes are on the wedge wire page.

Building or re-screening a well? Send the diameter, the setting depth and the sand analysis — we will confirm slot and wire section before you order.