The APX401 Vibrating Viscometer Assists in Controlling Cement Slurry Processes

We recently supplied a batch of APX401 online vibrating viscometers for a wet cement production line, specifically for viscosity monitoring in the raw slurry process. The project had fairly specific requirements for the instruments-the medium is raw slurry used in cement production, and the connection follows the HG/T20592 standard using DN50 PN16 RF flanges. The material was specified as 316 stainless steel, considering the corrosive nature of cement raw slurry on conventional materials; 316L ensures long-term stability.

In terms of process parameters, the viscosity on-site fluctuates between 50 and 2500 cP. While not extremely high, the raw slurry contains solid particles and is a typical solid-liquid two-phase flow, placing high demands on the viscometer's anti-fouling and wear resistance. The APX401 we selected has a measuring range of 0 to 100,000 cP, fully covering the actual operating conditions, with an accuracy of 1%, meeting the production line's requirements for controlling slurry consistency. As for pressure, the pipeline pressure on-site is only 5 bar, well within the instrument's capacity, requiring no special treatment.

Regarding installation, the user specified a split design, with the sensor inserted 230 mm into the pipeline and a 10-meter separation cable. The cable was explicitly marked as non-cuttable-an important detail because the cable length for a vibrating viscometer affects signal transmission characteristics; cutting it could lead to measurement deviations. The explosion protection rating on-site is Ex d IIC T6 Gb, a relatively high level for gas explosion protection, suitable for areas in cement plants where flammable gases may be present. The instrument was equipped with an explosion-proof junction box and a rail-mount housing, allowing for direct on-site installation.

Power supply and output were relatively standard: DC24V power, with dual 4–20 mA and RS485 outputs. This allows for real-time control via the DCS and also enables reading more detailed parameters through the RS485 interface for data analysis. The APX401, as a vibrating viscometer, has a natural advantage in cement raw slurry applications-it has no moving parts, so it is less prone to being clogged by slurry, and routine maintenance is minimal, basically limited to periodically cleaning the probe surface to prevent material from drying and building up.

Overall, feedback from the field indicates that the measurement data are quite stable. Especially when the raw slurry concentration fluctuates, the viscosity responds quickly, promptly reflecting process changes. For wet cement production lines, the stability of raw slurry viscosity directly affects energy consumption in downstream processes and final product quality. Having an online viscometer for real-time monitoring is far more accurate than manual sampling and lab testing, and it eliminates the time lag associated with sampling and analysis.