Pixact Bubble Monitoring


The Pixact Bubble Monitoring (PBM) system is designed for the online analysis of bubble suspensions and foams in industrial processes. The measurement is based on the direct optical imaging of the suspension combined with advanced image analysis. The images of the suspension are processed in real time with powerful analysis algorithms for statistics such as bubble size distribution and its derived values, including mean bubble size, standard deviation, the Sauter mean diameter and parameters of cumulative distribution (D10, D50, D90, etc.).


Two configuration options are available for PBM: the Pixcell flow-through cuvette for installation on process lines or dedicated sampling lines and the Pixscope probe for installation on reactors and tanks.

Results produced by PBM


The PBM technology can be used for measuring both foams with high air content and bubble suspensions with lower air content. The foundation of PBM is the live image view of the suspension, which provides the operator with valuable visual information on the process.


The proprietary image analysis algorithms of the measurement system detect bubbles and other particles in the image data and produce detailed real-time numerical information on their characteristics and other suspension properties.



Measurement results produced by PBM include:

  • Bubble size distribution and related statistics, such as Arithmetic, Sauter and volumetric mean diameter, and percentiles of cumulative distribution (D10, D50, D90, etc.)
  • Bubble count
  • Bubble concentration
  • Bubble flow velocity



The measurement information on the size of the bubbles and suspension homogeneity helps to optimize, control and troubleshoot the process. With PBM the yield and efficiency of the process can be increased and quality variations in the final product minimized.

PBM performs exceptionally even in dark and/or dense suspensions. Additionally, both the software and the hardware of the system have plenty of customizable features. Together these two qualities ensure that the system can be applied to a wide variety of processes.

For the operator, PBM provides tools for

  • Visual examination of the bubble suspension or foam with a live camera view (featuring zoom, pause, etc.)
  • Accurate process control and detection of disturbances on the basis of real-time statistics on suspension characteristics



  • Documenting and reporting process states and changes in the process with reports including complete statistics and example images

To increase productivity and promote Best Practice methods, PBM can be used in production development for

  • Benchmarking individual reactors and recipes
  • Comparing plants with each other
  • Collecting production databases to help with troubleshooting in case of disturbances

In R&D, PBM supports

  • Lab-scale work by providing new insights into process dynamics and related physical phenomena
  • Scale-up work by using the same measurement equipment from the laboratory to manufacturing

PBM measurement hardware and software


The PBM hardware consists of a Pixcell cuvette or a Pixscope probe and a Pixstation main unit.

The Pixcell flow-through cuvette is ideal for installation on process lines and dedicated sampling lines. The bubble suspension or foam flows through the cuvette, in which the images are captured.

The Pixstation main unit includes a PC workstation and an automation interface. The cabinet is IP67-rated and can be installed in the production space and other demanding environments. The main unit can be customized with optional features, such as a monitor for local operation or a complete selection of automation interfaces. The design supports both fixed and mobile installations.

The PBM software is an all-in-one tool for analyzing and reporting measurement data.

The PBM software controls the entire measurement procedure from data acquisition to the reporting of results. It can be used as both a fully automated online measurement software and an effective R&D tool with access to all necessary settings as well as manually controlled data acquisition and analysis.


Key features of the software

User-friendly adjustment of imaging parameters

  • Automatic camera controls
  • Adjustable image refresh frequency
  • Zoom and pause of the live view

Powerful analysis algorithms

  • High-performance image analysis techniques that convert the image stream into real-time quantitative information
  • Customized image analysis features on request

Flexible reporting tools

  • Image data can be stored on an internal or external hard drive
  • Results exported in Microsoft Excel® or CSV format
  • Internal database for the measurement results

In addition to the live view of the process, the Pixact Bubbles software displays numerical values, trends and distribution plots for the parameters measured on the screen.

The Pixscope probe can be fitted into a wide variety of applications from laboratories to manufacturing scale reactors and tanks. The suspension is imaged as it flows through the measurement gap in the probe head.

The Pixact Bubbles software automatically generates a detailed measurement report for each batch or time period defined by the customer. In addition to numerical data, the report contains trends for selected results and time-stamped images of the process.

Typical applications


  • Analysis of flotation cell performance
  • Analysis of aeration and other mass transfer processes
  • Analysis of foam properties and homogeneity
  • Detection of gas in the process stream

Technical specification

System description

Measurement principle

Optical configuration options

Image area [mm]

Image resolution [µm/pix]

Measurement range [µm]

Power supply

Automation input/output


Online measurement system for the real-time analysis of bubble suspensions and foams

Direct optical imaging of the suspension accompanied by proprietary image processing and analysis techniques


25.5 x 21.0




8.5 x 7.0




4.3 x 3.5



All system components 24VDC, power supply unit 230VAC/50Hz

Profibus, Modbus, Analog (mA, V), Digital (5-24VDC)

IP67, ATEX on request

Pixcell cuvette

On process or sampling lines using DN10 or larger fittings


Standard models

Flow inlet/outlet:

  • DN10 (3/8")
  • DN15 (1/2")
  • DN25 (1")
  • DN50 (2")

Custom sizes and automatic washing cycle available on request

Pixscope probe


On process lines or process equipment using DN25 or larger fittings

Operating temperature

Max. operating pressure

Cuvette and probe head: -20C to +120C

Housing: -20C to +85C (cooling options available)

4 bar, higher on request

Probe dimensions



Measurement gap


Min. 25mm, standard 31mm

Max. 300mm, standard 100mm

1-20mm (fixed, not adjustable)


Cuvette or probe head


Optical windows

Sealing options


Stainless steel AISI316L (other materials on request)

Sapphire or borosilicate

NBR, PTFE, FPM, EPDM, silicone


(C) Pixact Ltd, 2018

tel.: +358 (0)10 439 2400         email: info@pixact.fi