Radial external wedge wire means the wedge wire is radial outside the support wire, and the support profile wire is axial. These wedge wire tubes are composed of a surface wedge wire that is spirally wrapped around an axial support profile wire and attached to each other by resistance welding. When the flow direction is from outside to inside (FOTI), the flat side of the surface wedge wire is on the outside of the tube. When the flow direction is from inside to outside (FITO), the flat side of the surface wedge wire is on the inside of the tube. Radial external wedge wire FITO type is also called a reversed wedge wire screen tube.
Radial Internal wedge wire means the wedge wire is radial inside the support wire, and the support profile wire is axial. Radial Internal Wedge Wire Type Tube is rolled-formed from flat wedge wire screen panels, which means there are many welding joining points and the inside wedge wire is not continuously spirally wrapped around axial support profile wires. Furthermore, radial internals only have one flow direction, which is FITO (flow in to out).
Axial Internal wedge wire means the wedge wire is axially inside the support wire, and the support profile wire is on the outside of the filter element in a radial direction. The smooth surface of the wedge wire or profile wire is on the inside of the filter element, so the filtration direction is from inside to outside. This means that axial internal wedge wire has only one flow direction, FITO (flow in to out), though FOTI (flow out to in) is also possible in exceptional cases. And for axial internal wedge wire, according to different slot sizes and filter sizes, there are two different types: one type is wedge wire type tube or cylinder that is rolled from flat wedge wire screen panels, which means there are many welding joining points. The other type is the outside support wires, which are continuously spirally wrapped around axial wedge screen wires.
Axial External wedge wire means the wedge wire is axially outside the support wire, and the support profile wire is on the inside of the filter element in a radial direction. The smooth surface of the wedge wire or profile wire is on the outside of the screen filter element, so the filtration direction is usually from outside to inside. But sometimes, the customers require Axial External Wedge Wire and FITO, which means the smooth surface of the screen wedge wire is inside. FOTI is used when there are no special requirements, such as for an axial external wedge wire. Axial External Wedge The wire tube or cylinder is rolled from flat wedge wire screen panels, which means there are many welding points on the inner supporting profile wires.