Concentric well screen filter design

Inspiration

We sought to design a filter which would optimize the filtration surface area while keeping the filter in a small container. In this design we wanted to improve on the traditional sand filter by changing the geometry of filtration.

Design summary

• The filter consists of two concentric well screens. The well screens are porous pipes which enable water to pass through but prevent sand from escaping. Pore size is on the order of 0.45mm.

• The concentric pipes are separated by a layer of packed sand. This packed sand is essentially a cylindrical filter bed.

• Raw water enters through the outer well screen, passes through the sand, and exits through the inner well screen.

• When backwash cycle is initiated, the flow is reversed and the bed is expanded analogous to conventional backwash.