Filtering liquids or air in hostile environments—such as those subject to temperature extremes, high orders of shock/vibration, and caustic fuels or fumes—has posed problems for paper filter elements. These types of elements simply will not withstand these types of operating conditions.

Paper or sintered metal filter elements are satisfactory for most applications. But where the filter must handle hot, corrosive or caustic fluids, or where the equipment is subjected to shock and vibration, conventional elements may dissolve or disintegrate. In such applications, a knitted wire high temperature filter and/or high pressure filter may be the only solution that can provide the required life.

Metal Textiles high temperature filters provide an economical, robust alternative. From cryogenic operating conditions up to temperatures of 650° C, knitted wire mesh filters maintain their integrity even when subjected to extremely high vibration and exposed to destructive gases such H₂, SO₄, and HNO₃.

Knitted mesh consists of wires of various metals or strands of other materials that have been knitted into a mesh structure—creating a matrix of interlocking loops that can move freely in the same plane without distorting the mesh.

Since paper filters are typically composed of organic materials, they are also subject to attack by the caustic byproducts of many industrial processes. For example, corrosion often takes place when high-temperature lubricating oils are loaded with such acids. After extended use, the surface area of the paper filter becomes heavily loaded, resulting in filter weak spots. (If the pressure relief valve is not set low enough, and the pressure is allowed to remain at normal operating pressure [500 to 700 kPa], paper filter elements may tear, fracture, or even burst.)

In addition, each loop acts as a small spring when subjected to compressive stress. Thus, filters of compressed knitted metal mesh yield when subject to the stresses of shock and vibration—yet, depending on the construction, can immediately recover to 90% of their original size when the force is removed.

Greater filter efficiency
Even when compressed to extremely light densities, or where pore size is larger than the particle size of the contaminate, Metal Textiles knitted wire mesh high temperature filters achieve proper filtration and small contaminate particles are efficiently removed from the fluid stream. In addition, the tortuous path construction results in greater dirt-retention, without blockage, than can be expected from other filter media. Knitted mesh filters are resilient enough to fit (or retrofit) into filter cavities of virtually any configuration and still retain a secure friction fit.

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