Having operated in the filtration market for over 30 years, Croft Filters has provided various filter designs to wastewater treatment plants.
Croft Filters have recently developed an innovative filtration solution, the EXOStructure Filter. Through combining traditional manufacturing methods with the latest Additive Manufacturing (3D printing) technology to overcome some limitations of existing filtration solutions.
When using woven wire mesh for filtration, it must have sufficient strength to support the final shape of the filter. This is usually achieved through the mesh wire diameter having sufficient strength to be formed into the shape, however this decreases the size of the apertures.
That’s where Croft Filters’ EXOStructure Filter comes in.
This innovative solution is designed to increase strength and stability of mesh only, woven wire filters with the addition of localised supports. The EXOstructure filters can be made with smaller wire diameters, delivering woven wire mesh filters with smaller filtration levels.
Compromising of stainless-steel woven wire mesh, a number of filter shapes can be created depending on the application needed. Extra support structures can also be added to suit operational pressure requirements. This ensures the shape of the woven wire mesh is maintained in the final filter format.
Securing the loose ends of the wires, the addition of a metal support frame around the edges of the woven wire mesh holds them in place, avoiding any being dislodged during operation. It also provides solid edges for welding into the final shape for the main filter body, ends and fixings.
The area of the supports added here is less than that of a traditional perforated filter support. This ensures the maximum open area of the mesh is obtained, delivering a greater filtration efficiency.
EXOStructure Mesh Filter Manufacturing method
Traditionally, mesh is cut and formed into a cone with the help of a jig and is then spot welded along the seam. A cone filter manufactured from Stainless steel 316L mesh holds its shape but can easily be distorted by operator and operation. Additionally, wire ends are free and not held in position, which may affect the aperture size and shape of the final product.
Croft’s EXOStructure Mesh Filters are manufactured from woven wire mesh with supports added by Additive Manufacturing. Also known as 3D printing, this is the process of manufacturing components through the addition of material in a series of layers melted or fused together to create the part.
Forming the filter’s support material, the mesh is spot welded to a base plate and a layer of SS316L powder covers the base plate before being melted using a laser. The mesh and supports are then removed from the AM build plate. Filter body and ends are cut out, and then formed again using another jig.
Ensuring that the mesh shape is cut without distortion, the ends of the mesh are held in place. To finish, the support material seam, end and fixings are laser welded to create the quality, improved performance products.
This process enables a variety of different ends and fixtures to be secured to the filter mesh more easily and with greater precision. It means the EXOstructure filters can be manufactured to a more consistent specification when compared to the previous manufacturing process.
Manufacturing & Supplying Custom Filters
This new production method has enabled Croft to supply EXOstructure filters to customer specifications, updating the customer’s previously manufactured bespoke filters.
EXOStructure filters have been supplied to the automotive and autosport industries for use as last chance filters in fuel systems. The filters can also be used in various applications for food & beverage, oil & gas, chemical, pharmaceutical, automotive, utilities & waste management and marine.
The new filters were found to maintain their shape and the mesh wires were retained within the filter. Following their successful use of EXOstructure filters, customers have since had further filter designs developed using this method.
Croft can supply a wide range of custom filters from simple yet effective designs such as witches’ hats, screen filters and filter baskets, strainers and cylinders to complex, made for purpose designs. Quality is the key to our success and we can supply products in a short lead time, as little as 2 days, minimising the downtime within our customers’ filtration system.
Improving filtration efficiency can be a challenge. Especially for companies that are trying to deliver the highest possible open area across the filter media.