Wet System

Wet systems

Wet process applications require a different approach to online particle size measurement than dry powder systems. In many industries, the material being processed is transported and handled as a slurry rather than as a dry powder. Since particle size distribution remains one of the most important process parameters, dedicated wet measurement systems are required to provide continuous PSD information directly from the process stream.

Online wet particle size measurement is commonly used in mining, mineral processing, flotation circuits, hydrocyclone overflow monitoring, pigment production, specialty chemicals, battery materials, ceramics, and other slurry-based processes. In these industries, particle size directly affects downstream process performance, product quality, recovery rates, filtration efficiency, and overall plant productivity.

As with dry systems, obtaining a representative sample is critical. The measurement itself may be highly accurate, but if the sample is not representative of the process stream, the resulting PSD information has little value. Xoptix therefore provides complete wet sampling and measurement systems rather than simply supplying an analyser. The entire sample path is carefully engineered to ensure that the measured PSD accurately reflects actual process conditions.

In many installations, sampling is achieved using a bypass arrangement. A small portion of the process slurry is continuously diverted from the main process pipe and directed through the measurement system. The bypass flow is carefully controlled to ensure representative sampling while minimising disturbance to the process itself. This approach is often the simplest and most reliable method of obtaining a continuous sample stream.

Where more complex sampling requirements exist, dedicated wet samplers can be incorporated into the system. Sampler design depends on factors such as slurry density, particle size, pressure, flow velocity, process layout, and installation constraints. Xoptix works closely with customers and specialist partners to ensure that representative sampling is maintained under all operating conditions.

Following sample extraction, the slurry typically passes through a dilution stage before measurement. Dilution is often necessary because industrial slurries can contain particle concentrations far higher than those suitable for laser diffraction analysis. The dilution system reduces solids concentration in a controlled and repeatable manner while preserving the original particle size distribution of the sample.

Xoptix has developed dedicated dilution technologies specifically for online operation. These systems provide stable and repeatable dilution ratios despite variations in process flow, slurry density, pressure, and operating conditions. Proper dilution is essential for achieving reliable optical measurements and maintaining measurement stability over long operating periods.

Measurement is performed using a dedicated wet version of the IntelliSizer. While based on the same laser diffraction principles as the dry instrument, the wet system incorporates specialised flow cells, optical arrangements, and sample handling components designed specifically for slurry applications. The analyser continuously measures the diluted sample and calculates the particle size distribution in real time.

The wet measurement cell is designed with a narrow optical gap to accommodate the higher optical attenuation typically encountered in slurry applications. Even after dilution, many process slurries remain significantly more concentrated than dry aerosol samples. The carefully controlled optical path ensures stable measurement conditions while maintaining sensitivity across the required particle size range.

After measurement, the sample can either be returned to the process or discharged to waste, depending on application requirements. In many mining and mineral processing installations, returning the sample to the process is preferred to minimise material losses. In other industries, disposal may be more practical or required by process regulations.

The complete wet measurement system therefore consists of several integrated components: the primary sampling arrangement, bypass system or sampler, dilution stage, wet measurement cell, particle size analyser, control system, and sample return or disposal circuit. Together these elements provide reliable, continuous PSD measurement for demanding slurry applications and allow operators to make informed process control decisions based on real-time particle size information.