ABEL CM – Spray Dryer Feed
In the ceramic industry, the spray dryer is the last phase of the powder preparation cycle. In a single operation it eliminates excess water used previously in grinding, while it at the same time produces perfectly homogeneous powder with granulometry and residual humidity. These are the ideal conditions for the next stage in compression. The greater part of this process involves spraying the slip into a current of air. A pump sends the ceramic slip under a set pressure through the spray nozzle placed inside the drying chamber. Within the nozzle the material is atomized upwards into a down flowing current of hot air emerging from a hot air generator. The opposing currents cause almost immediate drying. The powder then falls to the bottom of the dryer and passes through the discharge valve.
The customer is one of the largest tile manufacturers in Japan. It produces many tons of tile powder per day, utilizing three spray dryer units. The use of existing vertical plunger pumps imported from Italy and Germany caused the following problems in the 24h process:
- leakage in the cylinder due to highly erosive slurry
- damage of the piston caused by grain content in the slip
- difficult replacement of spare parts due to complicated design of the pumps
- very long delivery time of spare parts
- difficult and messy maintenance due to the use of oil as hydraulic medium
- pulsation in the discharge pipe
Since spray drying is a continuous and precise process, these problems became unacceptable. The 24 h operation requires an extremely reliable pump to maintain the production requirements in a highly competitive market.
The ABEL solution
lt was soon realized that the ABEL pump is better suited for the process than the existing plunger pumps. The ABEL Compact Membrane Pump can withstand highly abrasive slurries containing grains by using high strength polyurethane membranes and ball valves which do not allow any contact with precious internal parts of the pump, such as the piston and regulation devices. Due to the right use of material, no pollution of the ceramic slip with metallic or other particles.
The use of a large discharge pulsation dampener eliminates pulsation in the flow at any pressure and assures a continuous flow of the ceramic slip into the spray dryer. 24h Operation is guaranteed by having an operating pump and stand-by pump combination. The variable frequency drive controls the flow in order to compensate not only the wear of the spray nozzles but also to enable the production of various kinds of powder qualities.