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Continuous Performance Improvements for the Pulp & Paper Industry         fax (770) 931-2664


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FreeEye Freeness Analyzer

The Optical FreeEye™ Freeness Analyzer for fast Process Analysis

The Optical FreeEye Freeness Analyzer is an in-line sensor that uses a combination of optical measurement along with other existing process measurements to generate and display a signal for the actual freeness.

As the stock passes by the optical sensor, an optical measurement is made. Using data collected from the mill’s control system, obtained through an OPC interface, a calibration model converts the spectrum data to a reading corresponding to the freeness at that point.

The model is calibrated using a sampling system. An automatic sample valve is installed near the sensor. A pushbutton on the local control panel at the sensor activates the valve to collect a sample. The sample time is recorded automatically by the onboard processor. After the analysis is performed, the results are entered into the system utilizing a data entry application that is loaded onto an existing lab computer.

High Consistency Sample Valves for Charge sample

Comminication
Communication to the analyzer is provided via an onboard wireless transmitter. Mill personnel will have to install the wireless receiver near an existing hub on the process control or mill network to allow communication to the OPC or PI server and the lab computer where lab data is entered.

Freeness Application
Freeness, or drainage of a pulp suspension on the paper machine wet end, is one of the most important variables that affect the quality, productivity, and efficiency of papermaking. Generally, it is very difficult to predict stock drainage behavior on the paper machine. The FreeEye Freeness Analyzer has been developed to provide a real-time value of freeness for information and as input for automatic control of the refiners. In this way, paper machine performance is improved dramatically.

Freeness is a measure of the rate at which water drains from a pulp suspension through a mesh screen or a screen plate. It is measured to assess drainage characteristics of stock during stock preparation at some location before the paper machine head-box. This characteristic, which depends upon the pulp stock, fiber flexibility, and the fines content of the pulp, can be used as an indication of sheet formation, and affects the final sheet properties such as tensile strength, burst, tear, and fold. With an accurate on-line freeness measurement, papermakers can identify the causes of stock variation, adjusting the furnish component, amount of recycled pulp, and refiners load, to minimize or eliminate the stock variation and increase production efficiency. Improved uniformity of stock drainage on the wire, leads to less load on the refiner and more efficient drying. This reduces energy costs, increases production, and improves paper quality.

Reliable measurement for Process Control
In addition to having no limitations associated with paper machine speed, the online optical FreeEye Freeness measurement system operates with one second measurement frequency giving a fast response rate for feedback control of the refining. At this higher frequency, It can also act as a feed-forward signal in strategies for vacuum and wet-end control.

Refining Control is the most common application for freeness measurement. Changes in the refining control have direct affect on the drainage rate at the wet end of the machine. The measurement can be utilized as a cascaded set point for Refiner Load Control. Mills have repeatedly reported fewer web breaks after implementing refining control based on freeness resulting in higher machine efficiencies. Freeness also correlates directly with some of the strength properties of the paper and can be used in real time models to predict strength properties.

Manufacturer: Conmark Systems Inc; Atlanta, Georgia

Technical Specifications:

  • Sensor Body & Connector: 316L Stainless Steel
  • Sensor optical Lens: Sapphire
  • Sampling: Pneumatically activated
  • Inputs: Optical sensor, OPC link to mill process variables
  • Outputs: Wireless Ethernet link to OPC server
  • On site access: Local color display
  • Remote access: Modem, VPN (Internet)
  • Temperature Rating: 32 ° to 212° F Constant 32 ° to 300° F
  • Measurement Range: 760 -110ml