G BOPP & CO AG, established in 1881 in Zurich, Switzerland, as a sieve and screen-making company, is today one of the world’s leading weavers of precision wire cloth in austenitic stainless steel and higher alloys. With wholly owned subsidiaries in Germany, England, Italy, Sweden, the USA, Korea, and China as well as a worldwide network of representatives, Bopp maintains its market-leading position as the number one manufacturer of precision-woven fine wire cloth. Bopp weaves mesh with wire diameters as fine as 15 microns; produces about 340 km of woven mesh (about 170 tons) per year; draws a substantial portion of its wire requirements by producing 1.5 million meters of wire per day or about 50 tons per year with capability to draw diameters down to 18 microns. From fine plain and twilled square weaves to twilled and reverse Dutch weaves, the company’s weaving capabilities span a wide range of weave geometries.
Bopp also performs a secondary process of Sintering (Diffusion-Bonding). Sintering takes place in a controlled atmosphere furnace with some degree of isostatic pressure and molecularly bonds all wire crossover points within a single layer of mesh. The benefit is that the mesh aperture size will not change, even under load. Multiple layers of mesh can also be sintered together. Not only are all crossover points in each layer bonded, but all contact points between layers are bonded as well, creating a plate-like composite. Structural strength may be imparted to an otherwise "flimsy" fine mesh, or laminates with specific physical properties may be produced. Any combination and/or any permutation of meshes may be sintered together to achieve such physical properties as mechanical strength, controlled permeability, porosity, thickness, absolute aperture size, etc. The sintering process is performed in discrete flat sheets in size 1200 x 1200 mm.
Standard laminates such as Poremet and Absolta are five-layer, surface-loading, rigid filter plates available in filter ratings from 2-100 microns in type 316L stainless steel, type 904L stainless steel, and *Hastelloy® C-22. These media are exact replacements in most nutsche filters and filter/dryers and are ideal as chromatography bed support plates. Poreflo is a fluidizing medium (aeration plate) in 2 and 3-layer construction and offered in a wide permeability range. Poreflo is ideal for handling any fluidizable bulk solid. Applications include air-gravity conveyors, aeration beds, fluidized bins, and hoppers. Type 316L stainless steel is standard, with Hastelloy C-22 available on special request. All the above media are produced in 1200 x 1200 mm sheets with many specifications available from stock. Bopp offers complete fabrication services, including shearing, laser cutting, automated TIG welding, and much more.
*Hastelloy is a registered trademark of Haynes International Corporation