Sizing

Dryer Design
The size of any rotary dryer is determined by first calculating the amount of heat required to achieve the desired reduction of moisture at the design throughput. This quantity of heat must be transferred from the drying air stream to the material being processed at a rate dependant on, amongst other parameters, the air inlet and outlet temperatures and the velocity through the dryer drum. The diameter of the dryer drum is therefore related to the quantity of air required for drying.

The length of the dryer drum is related to the time required to effect the transfer of heat from the drying air stream to the material being processed and the time required to effect the transfer of the mass of water evaporated from the material to the drying air stream. The rate of heat transfer is also affected by both the drying air and material inlet and outlet temperatures.

Such calculations are carried out by computer, using programmes developed from data available through our long experience in handling a wide variety of different materials. Data may also be provided from test work utilising our pilot plant dryers either at our works in Nottingham or at the client's own production facilities.

Having determined the basic dimensions of the dryer and the design capacities or ratings for the burner, exhaust air fan, dust collection equipment etc. in this way, further computer programmes are employed to produce mechanical specifications for the equipment, including dryer drum plate thicknesses, tyre dimensions, support roller loadings, shaft and bearing capacities and drive power requirements.

Rotary Coolers
For the continuous cooling of particulate solids Simon Rotary Coolers are designed and manufactured to the same high standards and general mechanical specification as the Simon Rotary Dryer.

Cooling is achieved by passing the material to be cooled through a rotating cylinder through which also passes a current of cold air. Lifters or flights fitted to the internal surface of the cylinder lift and cascade the material through the cooling air stream.

The cooling air stream can be directed through the cylinder either in the same direction as the material (co-current) or in the opposite direction (counter-current). In many instances it is possible for the cooler to be an integral part of the dryer drum.

In addition, cooling may also be effected by passing the material to be cooled through a rotating cylinder which is externally cooled by a water bath or water spray system.

Other Rotary Equipment
Having the capability to design and manufacture rotary dryers and coolers leads to the capability for design and manufacture of a whole range of rotary equipment. Typical examples would be granulating drums for the fertilizer industry, coating drums for the chemical and agricultural industries and mixer/reactors for bulk pigment manufacture; in a range of diameters from below 1 Metre to 3.5 Metres and above, with ancillary equipment to suit individual client's specifications.