Installation and operating instructions: JUDO UNIDOS digital dosing pump systems JUD-KH 6-50 and 6-100 (cold water) / JUD-HH 6-50 and 6-100 (hot water)
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JUDO Wasseraufbereitung GmbH
© JUDO Wasseraufbereitung GmbH
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Revision level: 20.04.2017
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34
7.3
Chlorine dosing
Preliminary remark:
Chlorine is used as a disinfectant because of its oxidising and germicidal properties. Commercial chlorine
bleach (sodium hypochlorite solution) contains approximately 12 - 14 % of active chlorine. If chlorine
bleaching lye is dosed into water, the active chlorine content is reduced because of reactions in the water
pipe. This process is referred to as wastage. How significant the chlorine wastage is depends on the
biological loading of the system. Consequently it must in general be dosed in excess so that at the 1st tap
connection an adequate free chlorine concentration can be demonstrated. This excess is limited to 0.6 mg/l
free chlorine, where the concentration at the 1st drinking water drawing point must not exceed 0.3 mg/l.
With outgassing media such as chlorine bleaching lye, a high dosing capacity must be
aimed for to minimise bubble formation in the suction pipe or the dosing valves!
7.3.1
General example
Given:
-
JUDO chemicals used, e.g. JFC 20
-
Active chlorine content JFC 20, e.g. 12%
-
Specific density JFC 20 (at 20 °C): 1.22 g/cm³
-
System-induced back pressure, e.g. 6 bar
-
Limit value at 1st drinking water drawing point: 0.3 mg/l or g/m³ free chlorine
-
Addition at the injection point, e.g. 0.3 mg/l or g/m³ free chlorine
-
Max. addition at the injection point: 0.6 mg/l or g/m³ free chlorine
-
Dilution (to achieve a dosable solution), e.g. 1:20
Required:
1. Dosing quantity 1 relative to addition and active chlorine content
2. Dosing quantity 2 relative to dosing quantity 1 and specific density
3. Dosing quantity 3 relative to dosing quantity 2 and dilution
Solution:
1. Dosing quantity 1 relative to addition and active chlorine content
content
chloride
Active
Addition
1
quantity
Dosing
l
mg
2,5
%
12
l
mg
0,3
1
quantity
Dosing
2. Dosing quantity 2 relative to dosing quantity 1 and specific density
density
spec.
1
quantity
Dosing
2
quantity
Dosing
