Charge Demand

The ionTEK charge sensor measures the a.c. streaming current caused by the hydraulic shear of a reciprocating probe within a measurement cell and across gold electrodes. A process sample is taken and the solids reduced by 2 or 3 stages of filtration to leave a near colloidal sample. The sample is then transferred to the reactor vessel. Each titration batch preparation includes; a wash, a preliminary sample soak and a titration sample fill. The sample fills the 1 litre reactor tank which is re-circulated through the measurement sensor using a mixing pump.

A precision dosing pump is used to titrate polyDADMAC to a zero charge-potential end point. The amount of titrant chemical used to charge neutralise the sample is a measure of the cationic demand (μ.equiv/Ltr). A second dosing pump can be added for an anionic titrant (PVSK or CMC) if the system regularly becomes too cationic. Each batch measurement normally takes between 4 to 6 mins.

The CSU is designed to measure the charge level for up to two points.

The unit is easy to install, operate and maintain. Component design is modular and this allows an end-user to service the unit.

The ionTEK SCD charge sensor enclosed within a CSU package measures the ionic charge demand in the wet end. This measurement of colloidal dissolved materials at the wet end of a paper machine provides an indication of the charge balance affected by material and chemical additives. Conditioning the feedstock at the wet end to balance the charge demand level can reduce process variability. This will help to stabilise machine production and reduce raw material costs.

The CSU is a fully enclosed, free-standing cabinet which houses the reactor, sample filters and control electronics. The CPU provides a signal of the charge measurement either as a 4-20ma signal or via a comms. link. A separate 50 ltr. vessel holds the titrant (polyDADMAC) and metering pump. The concentration of the titrant can be diluted for each application.