KEB COMBIVERT F6 Instructions For Use Manual - page 64
5.3 requirements for the coolant
The requirements for the coolant depend on the ambient conditions as well as the used
cooling system. General requirements for the coolant:
requirement
Description
Standards
Corrosion protection according to
, water treatment and use of ma-
terials in cooling systems according to
VGB
Cooling water directive
The VGB cooling water directive (VGB-R 455 P) contains instructions about com-
mon process technology of the cooling. Particulary the interactions between cool-
ing water and components of the cooling system are described.
Abrasive substances
Abrasive substances as used in abrasive (quartz sand), clogging the cooling circuit.
Hard water
Cooling water may not cause scale deposits or loose excretions. It shall have a low
total hardness (<20°d) especially carbon hardness.
Soft water
Soft water (<7°dH) corrodes the material.
Frost protection
An appropriate antifreeze must be used for applications when the heat sink or the
coolant is exposed temperatures below zero. Use only products of one manufac-
turer for a better compatibility with other additives.
Corrosion protection
Additives can be used as corrosion protection. In connection with frost protec-
tion the antifreeze must have a concentration of 20…25 Vol %, in order to avoid a
change of the additives.
Table 24: Requirements for the coolant
Special requirements for open and half-open cooling systems:
Impurities
Mechanical impurities in half-open cooling systems can be counteracted when ap-
propriatewaterfiltersareused.
Salt concentration
The salt content can increase through evaporation at half-open systems. Thus the
water is more corrosive. Adding of fresh water and removing of process water
works against.
Algae and myxobacte-
ria
Algae and myxobacteria can arise caused by increased water temperature and
contactwithatmosphericoxygen.Thealgaeandmyxobacteriaclogthefiltersand
obstructthewater-flow.Biocidecontainingadditivescanavoidthis.Especiallyat
longer OFF periods of the cooling circuit preventive maintenance is necessary.
Organic materials
The contamination with organic materials must be kept as small as possible, be-
cause separate slime can be caused by this
Table 25: Special requirements for open and half-open cooling systems:
Damages at the unit which are caused by clogged, corroded heat sinks or other
obvious operating errors, leads to the loss of the warranty claims.
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reqUIreMeNTS FOr THe cOOLANT