Mild Descaling for Galvanised Surfaces – ZINKOFIX
Depending on the existing metallic surfaces in a system and of which composition the scale is an accordingly adapted descaling agent has to be used. We always supply an optimal adjusted combination of acids and inhibitors, so that our clients can start the chemical rehabilitation of their systems without undue delay.
ZINKOFIX – descaling agent for galvanised tanks and reservoires, cooling towers, pipings etc..
Descaling of Storage Water Heaters:
ZINKOFIX is suitable for descaling of virtual all storage water heaters; in particular galvanised heaters, heaters with enamelled surfaces, stainless steel heaters etc. can be descaled properly. A possible existing sacrificial anode (which consists almost always of magnesium and serves as corrosion protection) has to be removed prior to descaling.
Consumption of ZINKOFIX depends basically on the amount of scale deposit in the heater, but usually enough is about 5 to 10 % of the water volume (i.e. for a 100-lt.-heater one wolud need 5 to 10 kg of ZINKOFIX).
But if the quantity of scale is known, the need of ZINKOFIX can be calculated exactly (for 1 m2 scale deposit covered surface and 1 mm thickness of scale deposit 4 kg ZINKOFIX are necessary; see the ZINKOFIX datasheet on this too).
Summary of the modus operandi:
- At the beginning of the descaling activity the heater / tank / reservoire has to be empty and cold.
- Establishing of a purification circuit:
Out of an open surge tank the descaling solution is pumped into the cold water entry of the heater via a hose pump; at the warm water outlet of the heater a hose is fixed, whose opposite end is stick back into the surge tank; in this surge tank the ZINKOFIX solution is prepared and from there it is recirculated.
- As soon as the ZINKOFIX-solution is still active, but does not foam any longer, the solution is purged (don’t forget to neutralise it prior to that), the heater is filled with water and drained again.
- After recirculation witht SILIKO-GEL-pH6 (agent for subsequent-treatment) the heater is again drained and flushed with water.
- Then dismounting of hose connections, reassembling of the system, and flushing with water until this runs off clear and odourless.
Descaling of Cooling Circuits:
Material requirement here depends of course on the existing scale quanity too (mineral and boiler scale) – if the quantity of scale is known, the need of ZINKOFIX can be calculated exactly (see ZINKOFIX data sheet).
Very often the quantity of scale in a cooling circuit even cannot be estimated meaningful. In such cases the following empirical formula proved one’s worth in practice:
The ZINKOFIX-need is thereby about 5 – 10 % oft he minimal water quantity which is necessary to enable a cooling tower operation. If then the minimal water volume of a cooling circuit is e.g. 500 lt. a need of about 250 to 500 kg of ZINKOFIX follows from this.
It is important too that a descaling with ZINKOFIX ought to be carried out only at room temperature (max. 30C).
Summary of the modus operandi:
- Remove slack scale and dirt mechanically; now adjust the minimum water level necessary for a duly cooling tower operation. Ventilators of the cooling tower have to be disconnected during total time of cleaning.
- The calculated quantity of ZINKOFIX related to the water volume of the system (minimum 5 %) is pre-dissolved in water and introduced to the cooling trough; turn on recycling pumps for 2 minutes, then break for 15 minutes – repeat this procedure.
- As soon as slurry and gas formation is finished and the ZINKOFIX solution still is active (chemical reaction with calcite) the contents of the cooling system is discharged (usually after 4 to 8 hours). Neutralize with calcite before!
- Intermediate flushing with water, introduction of a 1 % (bw) solution of TRINEUTRAL, recirculation, examination of pH value (min. 7), discharging.
- Finally flush again, until the system is clean.