Metal-wire mesh weave types

The twill weave is similar to the linen weave. In this type, each warp wire ties to at least two weft wires and vice versa, each weft wire ties to two warp wires. Warp and weft wires are not as securely fixed to each other, as it is the case with the linen weave. Depending on the choice of material, mesh size and wire diameter the mesh is already displaced during the weaving process. The mesh can be diamond-shaped and feature unequal lateral lengths. The mesh displacement continues under loads. This weave type enables very small mesh sizes. At a mesh size of only 20 µm, the filter-effective cross section is still over 25 %. Furthermore, the twill weave features a high number of meshes, even with the smallest mesh size. Therefore, it is well suitable for filtration purposes. Flow resistance, contaminant retention, and regenerability are comparable to those of the linen weave.

In the five-heddle atlas weave, each fifth warp wire is tied by the weft wire. Through this weave type, a smooth surface and an open bottom side are created. The meshes are shaped longitudinally. The smallest mesh size is bigger than 50 µm. This weave type allows for the use of wires that have a larger diameter than the mesh width. The chosen wire combinations enable a high flow rate. The mesh has a good mechanical resistance and is perfectly suitable for filtration purposes. Due to the smooth surface of this mesh dry cakes, for instance, can be removed easily. Therefore, it can be cleaned very easily and fluids can run off easily due to the open bottom side.

In the “single plain Dutch weave”, the linen weave-style weft wires are struck together closely. The warp wires are laid out with a large distance to each other and are thicker than the weft wires. In this way, triangular openings are created within the mesh. Even with small openings, the load capacity is much better compared to the linen or twill weaves. The free filter-effective cross section is below 20 %; hence, the contaminant retention is low. Due to the weave type, contaminants penetrate the mesh. Nevertheless, it is well suited for filtration purposes. The flow resistance is low. The regeneration is more difficult compared to a linen or twill weave. Due to the backwash capability, however, the mesh can be cleaned easily.

This weave type corresponds to the “single plain Dutch weave” except that considerably thinner weft wires are struck together leading to a considerably higher amount of openings and, thus, to a very high contaminant retention. The filter density is comparable to the single plain Dutch weave with a significantly higher flow rate. Depending on the design, the filter-effective cross section is 27 % to 42 %. In addition, the basic structure is advantageous: due to the chosen wire combination, contaminants mostly do not deeply penetrate the interior of the mesh, but cling to the mesh surface. The regeneration is better in comparison to the linen weave and due to the backwash capability it can be cleaned easily. Therefore, the optimised single plain Dutch weave is an extraordinary filtering medium and very well suited for filtration purposes.

In this weave type the narrowest opening is formed by three weft wires that cross each other in different directions. Together with the warp wires they create a channel that is open on two sides. In the Dutch twilled weave double the amount of weft wires can be struck together than in the single plain Dutch weave. This is achieved by the fact that the thinner weft wire skips two thicker warp wires and is reversed only half as often. Therefore, this weave type allows for finer filter densities than with all the other weaves. The mesh structure leads to a high filtering accuracy, although only a small part of the medium to be filtered follows the channel direction. It mostly flows transversely to the slot. However, in comparison to the other weaves this mesh has various disadvantages: the filter-effective cross section is significantly smaller and in addition the contaminant retention is lower. The flow rate is very low, which leads to a fast build-up in the mesh. The regenerability is poor. As a result, the practical application for filtration purposes is highly limited.

In the “broad mesh Dutch twilled weave” the weft wires are struck together non light-tight. This leads to a lower separation ratio and filtering accuracy compared to the regular Dutch twilled weave. This mesh has good flow properties and good regenerative properties, and enables a low pressure loss. Cleaning is easily possible due to the smooth surface on both sides. Therefore, this weave type is suitable for many filtration purposes.

In the “reverse weave”, or reverse plain Dutch weave, the warp wires are thin and the weft wires thick. The number of warp wires is significantly higher than in the single plain Dutch weave. As in the single plain Dutch weave, the weft wires are stuck together closely. The openings run transversally to the mesh surface creating a high filtering accuracy. Another advantage in comparison to the single plain Dutch weave is the considerably higher free filter-effective cross section as well as the significantly higher contaminant retention capability. The various combination of the number of wires and the wire diameter leads to a filter-effective cross-section of between 25 % and 38 %. The chosen wire combinations allow for a high tensile strength and withstand high mechanical loads.

n the “reversed Dutch twilled weave” the warp wires are also thin and the weft wires thick. Hence, it is referred to as a reversed weave, or twilled reverse Dutch weave. Due to the twill weave the warp wires are subject to significantly lower stresses as it is the case with the plain weave. Therefore, the mesh is suitable for applications with very high mechanical loads. Flow rate and filtering accuracy of the chosen wire combination is good.