Water and Combi Steamers
News Dated: Tuesday, March 19, 2002
As background information, steamer technology requires water of a very high quality. Chlorides (soluble salt compounds), chlorine, hardness and sodium are all enemies causing scale build up, corrosion and inefficiency. Some water treatment systems work better than others for certain types of water but operator input (cleaning/deliming) is essential as no system will be 100% effective. Not all water going to the steamer needs to be of such high quality, only to the steam generator. Water for the condenser should preferably be softened.
Different waters require different pieces of equipment as pre-treatment to steamer ovens. As a rule of thumb all steamer supplies should incorporate a minimum of 5 micron filtration for particle reduction and carbon for chlorine removal. After this the water make up determines what is required.
Another factor that also has to be considered is the water flow and pressure available on site. We know of instances where the pressure available to a site has been 6 bar but because of usage at peak times and pipework design (primarily sizing) less than 0.5 bar has been available to the steamer. This has resulted in ‘hot spots’ on boiler elements, burn out and accelerated scaling and corrosion.
The options available are: 1. Basic filtration with or without secondary storage 2. As 1 plus scale inhibition control 3. As 1 plus de-alkalisation (weak acid resin regenerated with H+ ion) 4. Reverse osmosis
Softened water is not suitable for steamer ovens because as well as causing corrosion, sodium deposits delay boiling time.
Different steamer manufacturers have different requirements but we have found reverse osmosis satisfies most demands. However in areas with a low TDS plain carbon filters should be sufficient.
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