Level limit detection in bulk solids

The storage and handling of bulk materials such as grain, flour and plastic pellets can be a high-risk activity and demands accurate and reliability level limit detection. A poorly designed high level limit switch may cause an overflow or a spill leading to wastage with an adverse financial and environmental impact. On the other hand, unreliable low-level measurements may cause inventory problems that negative affect a company's bottom line.

The Soliphant T FTM 20/21 switches provide a cost-effective and reliable solution for high/low level limit detection and overspill protection in silos and bins.

The FTM 20/21 uses a tubular construction with the second rod mounted concentrically inside the outer casing.

Compared to the alternative traditional fork or tine construction, this single stainless steel rod design is not susceptible to product build-up and obviates the possibility that material becomes embedded between the tines, increasing the instrument's reliability.

The 'balanced' rod design is achieved using the Kipp-piezo drive which is positioned at the base of the rod, not at the process connection. By decoupling the process connection from the vibration, the switch becomes insensitive to external vibration and flow noises, ensuring reliable measuring results.

The compact FTM20 model has a short 250 mm vibrating rod, typically for high level switching, whereas the vibrating rod in the FTM21 is supplied with an extension pipe in a choice of 500, 1000 and 1500 mm lengths for low level. These rugged 'fit-and-forget' limit switches have a maximum process temperature of 150°C, withstand pressure up to 16 bar and can be installed in any orientation.

The switches are designed for use in fine-grained bulk solids with maximum grain size of 25 mm and bulk densities up to 200 g/L. Typical applications include cereals, coffee beans/granules, sugar, animal feed, rice, detergents, dye powder, chalk, gypsum, cement, sand, flour, plastic granules, paper and pulp.