independent testing

Testing of KAL-GUARD+ was carried out by The School of Water Sciences, Cranfield University. All scale samples were dissolved in 0.1% HCl. In some cases, more concentrated acid had to be added during the dissolving process. Calcium content in the dissolved scale samples was then analysed using an Atomscan 16 Sequential ICP Spectrometer and the amount of scale formed then calculated. Results are shown as scaling rates.

A rapid scaling test was used to compare the scaling potential of water samples with and without treatment. The rig consists of 1 litre plastic tank, a heating element covered by removable sleeve and is temperature controlled (see Appendix 1). The water sample was heated to 70ºC for 45 minutes. Then it was discharged and replaced by a new sample in which the heater was allowed to cool down for 15 minutes and then reheated. The test solution was magnetically stirred during the whole experiment. After ten repeats the sleeve was removed from the heater and the scale dissolved in 0.1% HCl, analysed on ICP-AES and scaling rates were then calculated.

In these experiments scale formed on the heater sleeve and that formed in the bulk solution and on the walls of the tank was collected and measured. In the tests undertaken it was found that the water treated KAL-GUARD+ unit reduced the amount of scale on the heater sheath by 80% when compared to the control. The KAL-GUARD+ also reduced the level of scale formed in the bulk and when comparing the total amount of scale formed (combined heater + bulk) the KAL-GUARD+ reduced scale formation by 74%.

Analysis of the scale samples collected after the tests showed that the scale produced after treatment with the KAL-GUARD+ had more zinc in it than the control (Figure 5). Here it was found that 3.2 mg Zn mg CaCO3 in the heater scale and 5.8 mg Zn mg CaCO3 in the bulk scale.