A 6-inch loop seal in the condensate line ensures that the salinity cell is submerged at all times. A thermometer is located on the front of the preheater, and a pet cock for venting is located on the water box. The saltwater heater is mounted on the operating end of the evaporator and extends the full width of the unit. Feedwater enters and leaves the heater from the front water box after making four passes through the heater. It then flows past the desuperheater nozzle, which reduces the steam temperature in the shell of the heater.
Steam pressure is indicated by a pressure gage on the operating panel.
The entering steam is directed along the length of the tubes by impingement baffles. Steam con-denses on the tubes and falls to a condensate well at the bottom of the heater shell. The desuperheater atomizes the heater condensate in the low pressure steam side of the heater. The function of the saltwater heater is to pro-vide feedwater to the inlet of the first evaporator stage flash chamber. Since the amount of heat from the steam is constant, the feedwater flow through the heater must be adjusted according to the inlet temperature so that the feedwater flow is controlled by a valve on the outlet side of the heater.