Steam-Enhanced Unit

A steam-enhanced unit increases the efficiency of the basic evaporator in several ways. It uses evaporator pan steam to pre-heat the incoming sap. Additionally, air is pumped into the sap, causing it to foam; this greatly enhances the evaporation process. Note that the steam flows through channels or "flues" in the upper unit. These channels are more numerous than shown in the diagram and run the length of the unit. This creates a large surface area of steam warming the sap. Fresh sap entering the steam-enhanced unit is about 2% sugar. By the time sap enters the evaporation pan, it may be 4% or more sugar. Raising the sap from 2% to 4% sugar content means removing half the initial water. The Piggyback and STEAM AWAY are two types of steam-enhanced units.