Return sand cooler

Mixing implement in a cooler

In addition to the Webac Sandmixer, the return sand cooler is a key component of sand preparation. The moisture content and temperature of moulding sand are decisive criteria for the behaviour of sand during the moulding process. Temperature reduction takes place in the return sand cooler. In addition, the moisture content is adjusted to the optimum value for reactivation in the return sand bunkers.

To achieve this, various processes take place in the cooler:

  • Transportation and mixture of the sand
  • Moistening of the sand
  • Evaporation of the cooling water
  • Absorption of the water vapour

WAC batch coolers

Time diagram of a cooling cycle

Webac’s patented batch cooler represents a milestone in the further development of sand preparation. As well as its high cooling efficiency, it offers the advantage of early bentonite addition. Before starting the cooling cycle, the spent sand is weighed on two scales. With the aid of moulding and casting parameters, and of the measured weight of sand, the amount of bentonite to be added is calculated. The cooling process is divided into two phases. During the first phase, the sand is cooled. At the end of the cooling period, the second phase begins. The air supply is reduced to a minimum, and two binder injectors blow the bentonite into the sand bed. At this point the mixing time starts. After the two large emptying doors have been opened, and the batch cooler is completely empty, the cooling cycle ends.

WASK Continuous Coolers

WASK Continuous Cooler
Cooler types

The WASK-type return sand cooler is designed for continuous operation. Cooling is largely achieved by evaporation of the cooling water. The resulting water vapour is extracted with the cooling air from the cooler. The cooling air is blown in through large openings in the cooling basin below the level of the sand. The sand is fluidized and there is a large surface for evaporation. To minimize fine particles being carried out, great value is placed on low air speeds when designing the coolers.

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