Why do scale problems occur?
1. Hard water contains too many mineral ions such as calcium and magnesium.
2. Calcium carbonate is less soluble in hot water. (Inverse solubility)
20ºC 50ºC 80ºC
3. As water enters the heat exchanger, the solubility of CaCO3 drops. This is termed “Uncontrolled Precipitation.”
(Dissolved calcium ions)
Ca++ + 2HCO3 CaCO3 + H2CO3
Precipitation Scale Build-up
Calcium salts stick to metal surface due to
Why is scaling a problem?
1. Scale layers act as a thermal insulator, decreasing efficiency of the heat exchanger. Why? A result of the small thermal conductivity of scale.
Calcium carbonate k = 0.8 (W/m K)
Silica k = 0.08
Copper k = 393
Steel k = 75
(Conversion: 1 W/m K = 0.5781 Btu/hr ft ºF)
2. Narrowing of tube opening
- Flow rate through scaled tubes is significantly reduced.
What is ED 2000 Technology?
§ ED 2000 technology uses a signal cable wrapped around the condenser or heat exchanger supply pipe.
§ An induced, oscillating electric field is produced (known as Faraday’s Law).
The agitation of the electrically charged mineral ions is caused by the electric field and the rapid change of direction. The gauss strength of this field is only one gauss and not to be confused with magnetic treatment. (Refrigerator magnets have gauss strength of 1000 gauss. Magnetic treatment requires both velocity and the gauss strength to cause the same mechanical agitation.
Why is new scale prevented?
§ Solenoid-induced-molecular-agitation (SIMA®) precipitates dissolved mineral ions to insoluble mineral crystals.
§ These insoluble crystals are suspended in the water and float with the water, but do not stick to pipe walls and heat exchanger surfaces. Specific gravity is greater that that of water but the flow velocity keeps the crystals in suspension.
§ Hence, new scale is prevented