Q1. What is Hard Water?
When water is referred to as 'hard' this simply means, that it contains
more minerals than ordinary water. These are especially the minerals calcium
and magnesium. The degree of hardness of the water increases when more
calcium and magnesium particles are dissolved. Magnesium and calcium are
positively charged ions. Because of their presence, other positively charged
ions will dissolve less easily in hard water than in water that does not
contain calcium and magnesium.
Q2. What do you mean by scale?
Water has many dissolved solids in it. The salts of calcium and magnesium
are called the hard salts. These salts precipitate with the increase in
temperature and leave a white deposit on the surface of the exchanger tubes.
This white salt deposit is termed as scale, which acts as an insulator and
prevents the transfer of heat.
Q3. Why Scale off?
It is a non-chemical online type scale preventer, which does not require
any chemical. It works with a combination of adsorption, turbulence &
galvanic action. Inner core converts the hardness salts into colloidal
particles. Absolutely no recurring, operating and maintenance cost are
Q4. How does Scale Scale off work?
Working of Scale off can be explained in the following 4 steps:
Adsorption of H+ ions by the special metal alloy core.
Q5. What are the advantages of Scale off?
- There is an increase in the pH value in the next layer of water.
- With the increase in pH the solubility of water goes down.
- When the solubility of water goes down the precipitation of hardness
salts of Calcium and Magnesium begins.
- This precipitation is broken down into colloidal particles due to
turbulence. These colloidal particles are very small in size about 0.01µ
to 0.05µ. They remain suspended in the water in an interform. The
water can thus pass through the system over the heat exchange surfaces,
without depositing lime scale.
Q6. What are the application areas of Scale off?
- Prevention of scale and removal of existing scale.
- No extra electricity consumption.
- Saves energy due to no scale formation.
- No chemicals required, hence no recurring cost.
- No corrosion risk.
- No extra manpower required for maintenance.
- No pollution.
- 5 years replacement warranty.
- Comprehensive after sales service.
Q7. How does Scale off conserve energy?
- Air-conditioning plants: for condenser and chiller units
- Cold storage and refrigeration
- DG sets: water-cooled DG sets also face-scaling problem
- Injection moulding machines
- Heat exchangers
- Evaporating condensers
- Dye-casting machines
- Vacuum pumps
Water has many dissolved hardness salts of calcium and magnesium in the
form of carbonates and bicarbonates. These salts precipitate with the
increase in temperature and form scale deposits inside the exchanger tubes.
This scale acts as an insulator and prevents the proper transfer of heat. As
water flows through the Scale off a combination of pressure changes,
turbulence and galvanic action causes the dissolved scaling salts to be
precipitated as fine (colloidal) particles. These colloidal particles remain
suspended in water in an interform. The water can thus pass through the
system and over the heat exchange surfaces without depositing lime scale.
Hence upto 10% of the electricity can be conserved through the prevention of
Q8. How does Scale off eliminate the existing scale in
Scale off breaks the hardness salts of Calcium and Magnesium into fine
colloidal particles of size 0.01 to 0.05µ. These colloidal particles
while flowing over the surface of the exchanger tubes erode the existing
scale particles. Hence, the layer of scale diminishes with the passage of
Q9. How does it save electricity and how much?
We have an electricity savings chart wherein we do the calculations
according to the plant capacity, working hours/day/year and electricity
charges at per kW say for example client has 150 TR A.C. plant. After
calculations we found out that he can save electricity worth Rs.1, 53,000/-
annually, which is a good saving. So investment in Scale off is a wise
decision. (See home page to find out electricity saving with Scale off)
Q10. Calculations required arriving at a suitable model
Scale off ?
We have a model selection chart wherein we calculate the flow rate
according to the capacity of the condensers etc. With the help of flow rate
we determine the pipe size, length, weight and select the model.
Q11. When do you say the water is soft or hard depending
upon ppm of the salts?
Hard water is water that contains dissolved hardness minerals above 1
grains per gallon (GPG). GPG is a weight measurement, which is equal to 17.1
ppm (parts per million). Hence if the hardness minerals like calcium,
magnesium and manganese is less than 17.1 ppm in water then the water is
soft otherwise hard.
Q12. What is the process involved in a chemical water
A chemical treatment system like water softening involves the interchange
of one hard ion (calcium) for another soft ion of like charge (sodium) in
the resin. Hard water is passed through a bed of resins containing sodium
ions, which are exchanged with calcium ions in water. Thus the water is
Q13. How does adsorption of H+ ions from water occur in
scale off & doesn't it affect chemical composition of water?
Scale off has a special metal alloy core, which has an overall negative
charge. The water molecule has got one H+ ion and one OH- ion. The H+ ion
owing to its positive nature is attracted towards the core, which is
negatively charged. Hence we say that the H+ ions are adsorbed on the
surface of the core.
On the contrary we also have an alternate layer of OH- ions. In this layer
of water, the pH goes up and the water becomes alkaline since pH=1/ log
[H+]. This sudden increase in pH causes the precipitation of Calcium and
Magnesium carbonate salts. Once the precipitation has taken place, the core
brings the pH to normal by releasing the H+ ions. Hence we say that the
chemistry of water is unaltered when the water leaves the Scale Guard.
Q14. What's the time taken to install Scale off and
what is the pressure drop observed after installation?
It takes 1-2 days to install Scale off. This is mainly dependent on the
geography of the site like the height of water line & size (diameter) of
water line in which Scale off is to be installed. However, if it's a
project then the time required to drain the water from the pipelines is
saved, which normally takes 5-6 hrs. The pressure drop is minimal say 1-2
psi after the installation of Scale Guard, which is negligible.
Q15. Describe the role of condenser, compressor and Pump
in the cooling circuit. Criteria required for installing scale off?
A central air conditioning system that needs to cool and dehumidify uses a
condenser, evaporator coil, and refrigerant piping to operate. The
refrigerant is compressed in the compressor and run through a series of
tubes inside the condenser to remove as much heat as possible, then piped to
an evaporator coil as a warm liquid. Expansion of the compressed liquid
causes it to cool, and as the air passes over the coil, heat is extracted.
The cool liquid becomes a cool gas as it gathers heat from the air, and is
drawn back to the compressor to start the procedure again. The pump is only
meant to force the water from cooling tower to the condenser and back to
cooling tower.The criteria required for installing Scale off is that at
least 75% of the volume of water flowing in the cooling circuit must come in
contact with Scale off to be able to be treated.
Q16. Explain Reverse Osmosis?
To understand Reverse osmosis let understand the term osmosis. Osmosis is
the "movement of a solvent through a semi permeable membrane (as of a
living cell) into a solution of higher solute concentration that tends to
equalize the concentrations of solute on the two sides of the membrane. In
reverse osmosis, the idea is to use the membrane to act like an extremely
fine filter to create drinkable water from salty (or otherwise contaminated)
water. The salty water is put on one side of the membrane and pressure is
applied to stop, and then reverse, the osmotic process. It generally takes a
lot of pressure and is fairly slow but the water is pure.
Q17. Where should the sample water for testing should be
collected from & how computer simulations help you in arriving at the
quality of water?
Sample water has to be collected from the site itself. The computer
simulation Helps in checking the performance of scale off unit. Once the
complete analysis of raw and recirculated water are fed into computer, the
programme gives the behavior of water at different stages. For the perfect
working of Scale off, the Super Saturation Ratio (Sr) at Scale off should be
higher than Sr at condenser. Calculated Hardness (Hc) in cooling tower
should be equal to actual hardness (Ha) in an ideal condition with a margin
of 10 ppm. When Hc-Ha>+20 ppm we can< observe that the Scale off unit
is not working satisfactorily.
Q18. What after sales service do you provide?
Scale off technical advisors are trained and continually informed about the
results obtained in various applications. This entails analyzing the water
periodically and making visual inspections of the plant which is being
protected by Scale off. Should adjustments be necessary the appropriate
measures will be taken together with the customer.
Q19. Will the equipment rust or perform abnormally with
Equipment would not rust as it is made from special stainless steel. We
have already taken a five year replacement warranty. After five years if
there is disruption in the smooth working of Scale off concerned
dept/company have to opt for a new Scale off.
Q20. Why do I need a Scale off as I have already installed
a water softener?
For raw water generally softening plant is used to reduce the hardness, but
this hardness increases in the re-circulating water due to evaporation and
heat exchange that takes place in the circuit of the cooling tower It is
essential to treat re-circulating water as this is the water which goes to
the chillers/condensers The condenser is the heart of a chiller's
mechanical system so we need to protect them at any cost.
Q21. If I can use the water for drinking, why this cannot
be used for AC plant?
For drinking purposes, water need to be clear and bacteria free, while
hardness can be upto 600ppm. In case of centrally AC plant water hardness
should not be 10 ppm i.e why water treatment is necessary, even or
drinking/corporation water to avoid sc.
Frequently Asked Questions About Electrostatic Water Treatment
Q1. What is it?
Electrostatic water treatment is a method of conditioning water using the
physical and electrochemical effects of electrostatic fields to cause the
formation of tiny (colloidal) particles. Essentially it is a method of
Q2. How does it work?
By applying dc voltage to a submerged electrode we form a local
capacitor within the water, the piping system or treatment rack wall. Ions
of calcium, magnesium and bicarbonates are brought together in the bulk
solution to form colloidal particles which are then in a stable form not
subject to plating out or forming deposits within areas subject to the full
flow of treated water. These ions are moved from solution to suspension
in the bulk water. This change allows the water to dissolve
existing scale deposits.
Q3. Does the electrostatic treatment system kill bacteria?
No, however the Electrostatic Scale-off system is bio-static. That is
by changing the condition of the water, and allowing a natural rise in the
pH and the presence of chlorine in municipal water supplies bacterial
development is contained at or below industry standards. Most
bacterial prefer to live in an environment in which the pH is 8 or below.
Normally, the pH in a escale-off treated system will be above-8.5.
Q4. Does the electrostatic treatment cause corrosion?
No. The electrostatic field cannot cause corrosion because there is no
electron transfer as a result of the electrostatic treatment. Once scale,
sludge and bacterial deposits are removed from the system, corrosion
normally caused by these deposits will be controlled as well.
Q5. Do I need to continue testing my water?
Normally, the only water test required for a SCALE-OFF treated system is to
monitor conductivity and pH. This eliminates many other time consuming
tests that are required with chemically treated applications. A computer
simulation report shall be submitted after every water test reports for
Q6. Can I eliminate tower bleed altogether?
No, While it is possible to operate cooling towers at higher levels of
conductivity, continued bleed of the system is necessary to keep
concentrations of particulate matter at appropriate levels. Water use and
discharge fees will be reduced as a result of operating at higher
conductivity levels. Except in special conditions the normal and proper
operation of a tower will involve bleeding or blow down to maintain the
water conductivity at between 3200 and 3800 ms/cm of conductivity.
Bleed off in cooling tower bottom
: A bleed is set for following
Q7. Will old deposits of scale be removed?
- March - April - 1. 1% of water flow rate twice in a week.
- May - June - 2. 2% of water flow rate twice in a week.
- July - August - Sept. - 3. 1.5% of water flow rate twice in a week.
- Oct. - Nov. - Dec. - 4. 0.5% of water flow rate twice in a week.
Yes, old deposits will be loosened and dissolved slowly. In one case the
SCALE-OFF system was responsible for removing over 60,000 pounds of scale
that had developed in a cooling tower. It had taken over 15 years for
the scale to accumulate in this tower and it took only one operating season
for the Electrostatic scale-off to remove these massive deposits.
However, if the deposit is sufficiently thick so that it can cause a
loss of heat transfer efficiency or interfere with flow efficiency it should
be cleaned before startup. We recommend starting with a clean system.
Q8. How much power does the electrostatic system use?
Not Much, the operation of the SCALE-OFF system consumes about the same
power required to operate a 7 watt night light. That consumption
represents pennies per day of operating cost.
Q9. Are there any safety hazards in using an electrostatic
No, The SCALE-OFF system has been designed to provide the utmost
protection to those who may work with this innovative fluid treatment
process. The finest materials and manufacturing techniques are
employed to build our products. The potential for hazardous shock
is less than one would normally experience working with a typical household
Q10. Can Chemical treatments be eliminated or
Yes, in most cases the chemical treatments used to control scale,
bio-fouling and corrosion are eliminated. Since cooling towers are
massive air scrubbers, the total elimination of chemical additives may be
related to the location of the tower, local water quality and the condition
of the tower and related equipment.
The elimination of chemical additives for boiler applications and other
process water treatment is dependent upon many other variables. While
total elimination may not be possible a dramatic reduction of chemical
requirements for treating these applications is the normal.
Why do I need the Electrostatic scale-off System?
The most important reason is because of the increased cost of fuel and
water. It is becoming increasingly important to maintain scale-free
equipment systems to minimize energy loss. Scale buildup on heat transfer
surfaces can reduce heat transfer by 20% or more, cutting efficiency by more
The Electrostatic scale-off is also 100% environmentally friendly and meets
all EPA requirements. The Electrostatic scale-off System will prevent scale
buildup, maintaining clean surfaces for maximum thermal transfer in heating
or cooling systems.