SLDL5200 Series SoltaScan Radar Level Meter: A Precise and Reliable Level Measurement Solution for the Paper Industry

In the paper industry, level measurement is essential throughout core processes such as pulping, stock preparation, coating, and chemical preparation. From level control in pulping chests, to inventory management of chemical storage tanks, to process monitoring of coating preparation tanks, and continuous level measurement in bleaching towers and chests, reliable measurement data is required at every step. However, level measurement in paper production has always been recognized as a difficult challenge. The liquid in pulping chests is a thin slurry containing many floating fiber clumps, and the foam layer generated by agitation fluctuates with changes in slurry consistency. The lower section of a wood chip silo is a tall cone, where dust and humidity variations create unfavorable conditions. In bleaching towers, the pulp is highly dense and hot bleaching chemicals are introduced, making the environment highly corrosive. Traditional level instruments such as float-type, capacitance-type, or mechanical level meters tend to fail under these conditions: fibers wrap around sensors causing jamming, false triggering by foam leads to inaccurate level control, irregular wood chip accumulation causes measurement errors, and pulp buildup blocks instrument impulse lines, severely affecting production efficiency and product quality.

To address the complex measurement conditions in the paper industry, SOLIDAT has introduced the SLDL5200 series SoltaScan radar level meter, providing a systematic solution. This series adopts Frequency Modulated Continuous Wave (FMCW) technology. The transmitted signal is linearly frequency modulated over the working range, and the distance value is obtained by comparing the frequency difference between the transmitted wave and the echo. It can penetrate foam layers and suppress the effects of agitation fluctuations, enabling continuous, accurate, and reliable level measurement. The SLDL5200 series has a maximum measurement distance of up to 120 meters and accuracy up to ±0.5mm, meeting the measurement requirements of various paper industry vessels.

The SLDL5200 series includes multiple sub-models, each suited for different applications in the paper industry: the SLDL5200-81 general-purpose threaded type, with a thread size as small as 3/4″, is suitable for direct installation on compact tanks and small process vessels where space is limited; the SLDL5200-82 general-purpose clamp type and the SLDL5200-83 sanitary type use sanitary clamp connections that meet food-grade and pharmaceutical-grade cleanliness requirements, suitable for storage tanks of chemicals such as coating solutions and wet strength agents where hygienic conditions are required; the SLDL5200-84 lens type features a lens antenna design that resists condensation and material buildup, suitable for conditions with steam condensation such as bleaching towers and chests; the SLDL5200-85 universal-joint type allows on-site adjustment of the measurement angle, suitable for sloped vessels or installationrestricted locations such as wood chip silos and pulp chests. All models can be installed via threaded or flanged connections, support a wide temperature range from -50°C to 800°C and withstand pressures up to 160 bar. Key components are made of corrosionresistant materials such as PTFE, PEEK, and PP, enabling direct measurement of corrosive media including acids, alkalis, black liquor, white liquor, and green liquor.

The SLDL5200 series ensures stable operation in the complex conditions of the paper industry through several key technologies. The high-frequency signal provides a very narrow beam angle (as low as 1°), concentrating the signal to precisely avoid internal obstacles such as agitators and supports, achieving clear measurement even in confined spaces. The builtin oneclick false echo learning function automatically learns and suppresses multiple interfering echoes in the vessel, eliminating the need to fill or empty the tank during commissioning. The noncontact measurement design means the instrument does not come into contact with the medium, completely avoiding damage from fiber wrapping, pulp adhesion, and corrosive chemicals, and significantly reducing maintenance requirements. The instrument supports multiple fieldbus protocols including HART, Modbus, Profibus PA, and Foundation Fieldbus, as well as GPRS/CDMA remote communication, allowing seamless integration into existing DCS control systems in paper mills, enabling remote monitoring and closedloop control of level data, and providing critical support for automation and intelligence in paper production.

In the paper industry, the reliability of level measurement directly affects the uniformity of pulp preparation, the stability of feed to downstream paper machines, and the quality of the finished paper. With its precise signal focusing capability, strong antiinterference performance, and flexible adaptability to various operating conditions, the SLDL5200 series SoltaScan radar level meter provides an efficient and reliable level measurement solution for the entire paper process-including pulping chests, wood chip silos, bleaching towers, chemical storage tanks, and coating preparation tanks-helping paper manufacturers improve production efficiency, reduce operating costs, and achieve consistently highquality production.