Sodium fluoride has a reliable saturation solubility of 4%. By keeping excess sodium fluoride powder in a dissolving tank, a constant 4% sodium fluoride saturated solution is maintained. This is then dosed into the water supply, via a metering pump, in proportion to the mains
4-20 milliamp flow signal.
The saturator comes as a package all mounted suitable for ease of installation complete with overflow, drain, calibration cylinder, isolation valves and metering pump.
Two loading packages are offered.
For the smaller plants ProMinent offer their patented 5kg jar loader, for larger plants a vacuum loader.
ProMinent designed and patented a special loader to accept 5kg sealed NaF containers, slice the seal, and allow the powder to dump into the saturator tank. The container can then be flushed, by the push of a button, with clean water to allow the jar to be easily disposed of.
The vacuum loader especially designed for fluoride, is mounted on the saturator and comes complete with dust extractor, suction wand and a flexible hose. The ProMinent vacuum transfer system is designed to transfer powder from the 25kg bags to the solution tank.
With the vacuum loader switched on, the wand is inserted into the container or open bag. The vacuum motor will operate for approx 40 seconds before stopping, the inlet valve will close, and the dump valve will open, allowing the collected powder to drop into the hopper.
A cleaning cycle will then begin. Once the cleaning cycle has completed, the dump valve will close, the inlet valve will open and the vacuum motor will start again.
Two mandatory flow switches are required. One is taken off the 4-20 mA flow signal via the PLC, the other is normally a mechanical flow switch fitted in the mains water pipeline. A calibration cylinder is provided to accurately calibrate the metering pump against the dosing conditions. The metering pump is code locked to the maximum capacity to prevent overdosing. The metering pump is set to display the total amount dosed. This is compared daily against the total water flow to ensure correct dosing has occurred.