The weft wires are woven in a plain weave without a space between the weft wires (aperture width is 0). There are approximately 5 times more weft wires with respect to the number of warp wires. Hence the strength is higher in the weft direction. The SPW filter weave is used for surface fi ltration and is characterised by its ease of cleaning and back flushing. The pore size of the most common MINIMESH. SPW fi lter mesh cloth is within the range of 40 μm and 300 μm. To reduce pore size, single and double warp wires are used.