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Water Conditioning Scale Control
KalGUARD - Yes it works!
Tests at Cranfield University have confirmed that KalGUARD+ provides a reduction in limescale on heating surfaces of 80%.
KalGUARD+ provides the following benefits:
- Prevents limescale formation (see Critchill Court case study)
- Breaks down existing limescale, clearing systems and improving performance (see Critchill Court case study)
- Provides ongoing protection through passivation
- Reduces energy consumption
- Reduces CO2 emissions
- Eliminates the need for water softeners, thus reducing ongoing costs
- No COSHH implications
- Low maintenance (typically a visual check annually)
- Simple installation
- Assists in meeting energy targets
- Assists compliance with the Building Regulations
The Problem Identified
Limescale on the surfaces of pipes, heat exchangers and other water system components have significant implications for energy efficiency, system performance and plant integrity. Limescale in hard water areas has been a problem since people first started heating water and now makes a major contribution to the running costs of heating and hot water systems used in both building services and industrial applications. In the UK alone the cost of limescale formation to industry is estimated at over £1bn per annum and the cost to the environment through wasting energy is equally significant.
Studies have shown that a 25mm thick layer of limescale on a heat exchange surface will reduce heat transfer by 95% and this has implications for energy costs. Just a 1mm layer of limescale will increase energy costs by 7.5%, while a 12mm layer will raise this increase to 70%.
Limescale has the potential to impair performance at many points in a water system:
- Inefficient heat transfer on heat exchange surfaces
- Blocked pipes leading to early replacement
- Seized valves
- Blocked showerheads
- Unsightly deposits
The KalGUARD+ Process
It has been known for many years that the addition of zinc to hard water, even in minute quantities, will effectively inhibit limescale formation. The higher level of zinc ions in the water, the greater the effect on scale formation - to the extent of removing existing scale deposits.
KalGUARD+ exploits this phenomenon by using a zinc anode and copper cathode to create electrolytic action that releases minute quantities of zinc into the water - at levels well within the water regulations. The unit's electronic controls are set to the hardness of the water, so the levels of zinc released are fine tuned to provide optimum performance.
These zinc ions in the water cause the mineral salts in the water to clump together and remain in suspension, rather than settling onto the surfaces of the system. The zinc also influences the way the calcium carbonate in the water crystallises, encouraging the formation of soft aragonite crystals rather than the harder calcite crystals associated with stubborn limescale. The result is that as calcium crystals are flushed through the system with the water, any that are left on surfaces can be wiped off with a damp cloth.
Features & Benefits
KalGUARD+ provides an environmentally-friendly solution to limescale that saves money through greater energy efficiency, reduced maintenance and enhanced performance of water systems. Cost savings are achieved in the following ways:
- Maintains heat transfer efficiency by preventing scale build-up.
- Improves water flows by preventing pipes from scaling up.
- Reduces downtime of plant for de-scaling.
- Increases service life of plant.
- Minimises the need for chemical de-scaling treatment.
Frequently Asked Questions
Has KalGUARD+ been thoroughly tested?
Yes, the electrolytic action of KalGUARD+, using a zinc anode, has been tried and tested over many years in a wide range of applications. Building on the success of the original KalGUARD, KalGUARD+ incorporates electronic controls to synchronise the release of zinc to the hardness of the water. Tests at Cranfield University have confirmed that Kal-Guard+ reduces limescale formation by up to 80% compared to non-treated water and these results have been borne out in extensive field trials.
Is it safe to put zinc into the water?
Zinc is a naturally occurring mineral which forms an essential part of the human diet. It is found in high levels in grains and pulses and is one of the reasons these foods are considered beneficial to health. The levels of zinc released by Kal-Guard+ are relatively low, even at maximum dosage, and will not affect the taste of the water.
Will KalGUARD+ remove existing scale deposits?
Tests at Cranfield University showed that KalGUARD+ will remove existing scale deposits as well as preventing the formation of further limescale. However, if your system is badly scaled we would recommend thorough descaling prior to fitting.
Does KalGUARD+ soften the water?
No, KalGUARD+ is not a water softener. Water softeners remove calcium salts from the water,KalGUARD+ does not remove these salts but ensures they do not settle onto surfaces as limescale.
Independent Testing
Testing of KalGUARD+ 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. 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 KalGUARD+ unit reduced the amount of scale on the heater sheath by 80% when compared to the control. The KalGUARD+ also reduced the level of scale formed in the bulk and when comparing the total amount of scale formed (combined heater + bulk) the KalGUARD+reduced scale formation by 74%.
Analysis of the scale samples collected after the tests showed that the scale produced after treatment with the KalGUARD+ had moore zinc in it than the control. 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.
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