Wet Sampling

Wet-sampling

Wet sampling is the first and one of the most critical steps in any online slurry particle size measurement system. The objective is to continuously extract a small but fully representative portion of the process stream without disturbing the original particle size distribution. If the sample is not representative, the PSD result will not accurately reflect the actual process conditions, regardless of the quality of the analyser itself. Proper wet sampling therefore forms the foundation of reliable online particle size measurement.

Sampling wet process streams is often challenging because slurries may contain high solids concentrations, abrasive particles, varying flowrates, air bubbles, and changing process pressures. In addition, particles must remain fully suspended during extraction to prevent segregation between coarse and fine fractions. A successful sampling system must therefore ensure that the extracted sample accurately mirrors the composition of the main process stream at all times.

Xoptix wet systems are designed to continuously withdraw slurry directly from the process line using dedicated sampling arrangements selected according to the application. The extracted sample is transported to the dilution stage where its concentration is adjusted to the optimal level for laser diffraction measurement. Throughout this process, care is taken to maintain particle integrity and prevent changes to the PSD before the sample reaches the measurement cell.

The simplest method of wet sampling is to create a bypass loop around the main process line. A pump continuously withdraws a small portion of the process stream and circulates it through a smaller sampling pipe.

The complete sampling system is engineered as an integrated part of the overall online analyser solution. Factors such as sampling location, process pressure, slurry velocity, solids concentration, transport distance, and hydraulic design are all considered during system design. By combining expertise in slurry handling, sample transport, dilution technology, and particle sizing, Xoptix ensures that the analyser receives a stable, representative sample suitable for continuous real-time PSD monitoring under industrial operating conditions.

Selecting the correct sampling location is one of the most important factors for successful online particle size measurement. Xoptix engineers work closely with customers to evaluate the process layout and identify the most representative sampling point for each application. In mineral processing circuits, the most common and often preferred sampling location is the cyclone overflow, as it typically contains the final classified product and provides a well-mixed, representative slurry stream. However, every process is different, and Xoptix's experience in wet sampling helps ensure that the chosen sampling point delivers reliable and meaningful PSD data for process monitoring and optimisation.

For applications requiring highly specialized primary sampling solutions, Xoptix can work together with experienced industry partners who focus exclusively on complex sampler design and manufacture. This allows customers to benefit from proven sampling technologies for even the most challenging process conditions, while ensuring seamless integration with the Xoptix online particle size measurement system.