Introduction to Knitted Wire Mesh 

Knit Mesh is a tubular product that is flattened yielding a double ply. Knit Mesh may be cut, rolled, folded, stacked and compressed. Knit Mesh can be produced with different materials such as stainless steel 300 series, 400 series, polypropylene, Kevlar and cotton. All of these materials can be co-knitted with one another to enhance product capabilities, surface conditions and filtration characteristics. Knit Mesh is flexible and offers a free flow forming process for technical applications

What Is Knitted Metal Mesh? 

"Knitted metal" consists of wires of various metals or strands of other materials that have been knitted into a mesh structure. This knitting produces a matrix of interlocking loops that can move relative to each other in the same plane without distorting the mesh. Each loop is actually free to move in three directions, and the finished metal knit permits two-way stretch. Also, each loop acts as a small spring when subjected to compressive stress. Thus, filters of compressed knitted metal mesh yield to shock or vibration stresses, but immediately resume their original form when the force is relieved. 

Forms of Knitted Mesh

Knitted mesh is produced on a cylindrical machine. The output of this machine is a continuous “stocking” of mesh, which is pulled through the knitter by take-up rollers. It can be used directly in this flattened form as an insulation covering or it can be further processed into several other basic forms.

Flattened mesh is sometimes run through corrugating rolls to create crimped mesh. In this form, the corrugations act like springs for resiliency and give the mesh thickness.

Crimped mesh is also used to create compressed units for filtration, shock mounts and flame arrestors. In this case, the mesh is formed in a custom made die. These units are made in densities (% metal by volume) ranging from 10% to 70%. Compressed mesh is also made in a continuous strip form by running the mesh through calendaring rollers.

Mesh can be knitted directly into a hollow tube used by itself or knitted over wound-up mesh to make a cable or gasket core. It can also be rolled or padded to create filters, separators or flame arrestors. In all of the forms of mesh, density and wire dispersion are controlled closely to ensure optimum product performance and repeatability.

Properties of Knitted Mesh

Knitted metal has distinct advantages over most competitive materials. Because each loop acts as a small spring when subjected to tensile or compressive stress, knitted metal has an inherent resiliency. If it’s not distorted beyond its yield point, the material will resume its original shape when the stress is removed. Even when it’s compressed into a special shape, a high degree of resiliency is retained. Varying the knitted structure, wire diameter, wire material and forming pressure used to create the part can control this characteristic.

Knitted metal also provides high mechanical damping characteristics and non-linear spring rates. Vibration and mechanical shock can be effectively controlled to eliminate the violent resonant conditions and provide ample protection from dynamic overloads.

In compressed form, knitted metal can handle shock loadings up to the yield strength of the material itself. The load may be applied from any direction—up, down or in from all sides.

When compressed, layered, calendared or wound knitted metal presents a “tortuous” path to liquids or gasses flowing through it. This increases filtration capability and particle retention capacity.

Among the most important property of knitted mesh units is the material itself. By careful selection of the material or combinations of materials, Rishikesh Electromatic  can custom engineer solutions best suited for our customer’s application.

Most Commonly Knit Materials 

Mesh Diameters

Mesh is normally knit from wires ranging in diameter from .0035” to .0200”. In special applications, Rishikesh has knit wires ranging in diameter from .0005” to .0350”. These wires can be round or flat . A round wire when flattened has approximately twice as much surface area.

In filtration applications, wire diameter is perhaps the most important design variable. It directly affects flow, dirt holding capacity, pressure drop and cost. In general, larger diameter wire allows for higher flow but provides lower dirt holding capacity. Also, larger diameter wire is less expensive. Therefore, a balance must be struck between using a higher density filter of higher cost fine wire or a lesser density filter using lower cost heavy wire.

Density

Density refers to the mass of material per unit volume. It is related to the density of the original mesh and the amount of forming pressure used to compress the mesh into its final form. Determining the required mesh density to produce the specified final product density is a critical step in the design process. Proper density ensures optimal performance of the sealing, gasketing, filtration, heat transfer and separation applications.

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