Two Basic Types of Screens

Two Basic Types of Screens

There are two basic types of screens in the industry. The first is called wedge wire screen which is formed by laying stainless steel wires, having trapezoidal shaped cross-sections, parallel to one another with a small gap between them. The openings therefore are long slots with the width of the slot the nominal filtration degree as shown in the following picture.

You many notice that with a wedge wire screen, the shape of the target particles will greatly influence the efficiency of removal. Three dimensional hard particles will be removed at a much greater efficiency than flat scaly particles that could orient themselves to slip through the slots.

The second is called weave-wire screens, which have a discrete opening. A simple two dimensional square-weave would have rectangular openings. Some manufacturers of square-weave material form a rectangular opening with the length of the rectangle 2.5 to 5 times longer than the width. This can greatly affect the efficiency of the filtration process. 

However, most screens today do not use a square-weave but other weaves such as Dutch Weave and Double Dutch Weave. 

Applications of Wedge Wire Screen Filter 

This type of fully automatic self-cleaning screen filter has been used for decades in applications wherever suspended solids need to be removed from a pressurized water stream. They are used to remove sand, silt and algae from raw water taken from lakes, ponds, rivers and canals. Applications in steel mills filtering grimy, oily cooling and descaling water are common as are those in the automotive and plastics industries. Cement plants and mining operations use this type of filter for removing solids from tailings. They are found on deep-sea oil platforms for filtering flood water and on ships before portable desalination systems.