EPS Vacuum Unit - Evaporative Cooling

Water-Based Vacuum and Condensation

The evaporative cooling vacuum unit is the traditional and widely used method for extracting residual steam from EPS blocks after the fusion cycle. When the block form machine enters the cooling phase, the vacuum unit rapidly reduces pressure inside the mold cavity. This causes residual moisture in the block to flash into steam, which is drawn out of the mold and into the condensing tank. The result is a cooled, dimensionally stable block ready for ejection.

System Components

The core of the evaporative system is a cylindrical vacuum tank, available in either vertical or horizontal mounting depending on plant layout and ceiling height. Inside the tank, an internal condenser combines incoming steam with a water spray delivered through hydrospheres (perforated spray elements that distribute water evenly across the condensation zone). The steam condenses on contact with the cooled water, collapsing its volume and maintaining the vacuum level.

Condensed water and process water collect in a cooling pool beneath or adjacent to the vacuum tank. From the pool, water is circulated through a cooling tower where heat is rejected to the atmosphere via evaporation. The cooled water is then returned to the hydrospheres for the next cycle.

Water Discharge and Energy Savings

One practical advantage of the evaporative system is the option for gravity-based water discharge. When the plant layout permits the cooling pool to be positioned below the vacuum tank, condensed water drains by gravity without requiring a discharge pump. This eliminates one source of electricity consumption from the vacuum cycle, a meaningful saving across thousands of cycles per month.

Where gravity discharge is not feasible, standard centrifugal pumps handle water transfer between the tank, pool, and cooling tower.

Installation Considerations

Evaporative vacuum systems require an external cooling tower and sufficient water supply for makeup losses due to evaporation. The cooling tower must be sized to reject the full thermal load of the block molding cycle at the target production rate. Plants in hot or humid climates should account for reduced cooling tower efficiency when specifying equipment. Water quality should be monitored to prevent mineral buildup in the condenser and hydrospheres.