Pure water for best steam quality
When water evaporates, substances such as salts, silicates and dirt particles which do not pass into the steam remain in the boiler water. The boiler water in the pressure vessel thus continuously increases in concentration. This concentrated boiler water must be blown down regularly to prevent corrosion and deposits in the pressure vessel. Saline boiler water is also entrained in the steam and must be continuously discharged as first condensate into the blow down vessel. Both the blow-down water and the first condensate are pressurised and have steam temperature. In the blow down vessel, blow-down water and first condensate are relaxed and cooled before they may be routed into the waste water system.