The Wet End Charge Analyzer analyzer represents new advances in wet end charge measurement for papermakers. Online Charge measurement has demonstrated the ability to optimize wet end chemistry and control anionic trash. The Charge Analyzer is used as well to quantify the effect of various additives on system charge, providing a useful tool for assessing and improving process efficiency.
The analyzer is suitable for process control as well as an information source. Manufactured for easy maintenance and continuous trouble free running, and with over twenty years experience manufacturing wet end sensors, the online Wet End Charge analyzer is the most proven technology available in this field. No chemicals are needed for measurement. All the materials have been specially chosen for corrosion resistance.
The term "anionic trash" is now well established among papermakers. Today, the variability of furnish charge is discussed almost as commonly as consistency and freeness. It’s for a good reason. The stability of a paper machine’s electrochemistry, which significantly affects retention and drainage, is a critical factor in reaching the best possible quality and runnability with today's demanding paper machines and their forming sections.
Streaming Current Measurement
The general principles of how streaming current devices work are reasonably clear. It is generally agreed that streaming current is generated by hydraulically shearing counter ionic charges from temporarily immobilized particles, by means of a reciprocating piston within a cylindrical cell. Electrodes embedded in the surrounding cell measure the current produced by this action. The signal is then electronically processed and the output is the "Streaming Current". This current is due to the counter ions that are held close to the surface of the particle by electrostatic forces.
As originally developed, streaming current utilized a capillary passage or cell, through which a fluid or filtrate solution could be forced by an applied pressure. Counter ions in the diffuse layer (Slip Plane) surrounding the particle surface then migrate with the fluid creating an electrical potential or current, either of which can be measured. If the current is measured, it is termed as streaming current. This current can be mathematically correlated to the electrical potential at the surface of shear between stationary and mobile portions of the fluid.
Reliable measurements for Process Control
In many paper and pulp mills, the Wet End Charge Analyzer, has proven to be a solid tool for controlling both the process and the chemicals at the paper machines. The most typical installations in paper mills have been the automatic control of Wet End Charge Analyzer in the short circulation loop of the paper machine or in the wire pit.
Using multiple measurement points in the stock prep and wet end helps papermakers analyze the sources for anionic trash.
Wet End measurements
Several wet end measurements have been successfully used to help optimize additive usage and resolve problems such as deposits or poor runnability. There are many methods in existence for measuring the physical properties, of the papermaking furnishes, that influence machine efficiency. Among these are drainage, retention, formation, wet strength and others. However, very few methods exist for monitoring the performance and effectiveness of total wet end conditions and how the condition affects the runnability and number of breaks on the machine.
Today, the variability of the furnish charge, in the white water, among other properties, are discussed almost as commonly as consistency and freeness. The stability of a paper machine’s electrochemistry, which strongly affects machine drainage, retention and the machines draws, is the critical factor to maximize the runnability and produce the best quality paper on any kind of machine. Moreover, the wet end of the machine can be upset more easily with increased water system closure and the use of recycled furnish.
Accurate reliable charge analyzer technology and
optional data mining technology (Process Miner™) can help operators predict, analyze and correct
process conditions in the wet end of the paper machine.
Manufacturer: Micrometrix; Suwanee,Georgia;