1. The Duty of a Processing Conveyor Frame
Conveyors in a fish processing plant carry fresh or frozen product between washing, cutting, packing and freezing stations. The frame must support the belt, the rollers, the drive and the product load, and it must resist washing with high-pressure water and cleaning chemicals. Long frames are made from steel channels, whose U-shape gives high bending stiffness with a flat surface that is easy to keep clean.
2. How Web Depth Controls Deflection
The main rails of the conveyor run the full length between the head and tail stations and carry the load of the belt and product. Bending stiffness is dominated by the depth of the channel web: doubling the depth multiplies the moment of inertia by roughly eight times. A deeper channel therefore allows longer spans between supports without excessive sag, which keeps the belt tracking correctly and avoids product spillage at the joints.
3. How Flange Width Helps the Belt Support
The flanges of the channel provide the flat surface on which the belt support rails and the side guides are mounted. A wider flange gives more room for the mounting brackets and stiffens the section sideways, resisting the lateral forces from belt tracking. The return run of the belt can be supported on the inside of the channel, protected from product spillage and wash water.
4. Material Choice for Hygiene and Corrosion
Fish processing environments are wet, salty and chemically aggressive, so the frame material must resist corrosion. Galvanized or painted carbon steel channels are used in dry areas, while stainless steel channels are specified where the frame is washed directly or exposed to brine. The welds are ground smooth and the frame is designed without pockets where water or product can collect, in line with food hygiene practice.
5. Selecting the Channel Size
The channel size is selected from the span, the load per meter and the deflection limit. The designer calculates the required section modulus and picks the smallest channel whose modulus is sufficient, then checks the deflection and the local strength at the support brackets. Standard channels such as UPN or C series, Chinese channel series of GB/T 706, and JIS channels cover the range from 50 to 400 mm depth.
Frequently Asked Questions
Q: Why are channels used for conveyor frames?
The U-shape gives high bending stiffness for the weight, a flat web for mounting rollers and belt supports, and protection for the return belt inside the section.
Q: How is the channel depth chosen?
The depth is chosen so that the deflection under the belt and product load stays within the limit over the span between supports.
Q: What material is used in wet processing areas?
Stainless steel channels are used where frames are washed directly or exposed to brine, while galvanized or painted carbon steel is used in drier areas.
Q: Do the welds matter for hygiene?
Yes, welds are ground smooth and joints are designed without crevices so that product and bacteria cannot collect in the frame.
Q: Can the return belt run inside the channel?
Yes, the return run is often supported on the inside of the channel, which protects it from spillage and wash water.
Q: Which channel standards are commonly used?
Common series are the European UPN and UPE channels, the Chinese channel series of GB/T 706, and JIS channels, in depths from 50 to 400 mm.