Fluid Bed Drier

General Construction

The main body of the drier consists of the plenum chamber, the drying chamber and the hood. The plenum chamber is built in mild steel with angle iron frames of adequate strength. Sides, ends and floor are insulated with 2” thick mineral wool and cladded with galvanized sheet.

The drying chamber, including the perforated floor plates are all manufactured from stainless steel sheet AISI 304 food grade so as to meet the standards of food industry. An effective ball breaker, also made of stainless steel, is fitted in the inlet chute. The floor on the first section of the drier, the “wet end”, vibrates so as to counter the unavoidable force with which the tea leaves the ball breaker and ensures reliable fluidization.

The three sections of the drier and the discharge have suitable weirs to ensure the correct resident time for satisfactory drying at the rated output of the drier.

The hood is made from stainless steel AISI 304 food grade mounted on top of the drying chamber which has inspection windows to monitor the fluidization process.

Wet, mid and dry end cyclones are made in stainless steel AISI 304 food grade, Wet and mid end chimneys are also made in stainless steel AISI 304 food grade while the dry end chimney is made in galvanized steel.

These cyclones are fitted with 38” diameter Axial flow fans to exhaust air from the drying chamber and also to separate the dust/fibre from the teas and collect them into the cyclones.

The air to the plenum chambers is supplied by centrifugal fans fitted with 20 HP motor with swirl dampers to control the air flow into the plenum chamber.

The fans are coupled to steam radiators/air heaters of adequate size which are mounted direct on each plenum chamber.

The radiators use aluminium fins keyed to solid drawn carbon steel pipes and are hydraulically tested to 20 bars after complete assembly.

Normal steam working pressure is 8 – 10 bars but lower pressure can be catered for by fitting of extra bank/s to the radiators which are enclosed in mineral wool insulated casing. Each radiator bank is fitted with a full compliment of high quality steam fittings make- Spirax Sarco- UK

For mid and dry end section the last bank for radiator assembly are thermostatically controlled. A flash vessel is incorporated in the steam system for heat recovery.
Normally the main fans and cyclones are on opposite sides with a raised walkway fitted over the radiators to give access to the hood inspection windows. Where space is restricted the main fans and cyclones can be fitted on the same sides as in the case of compact design.

A standard 30” wide PVC belt conveyor is supplied to feed the drier. No special foundations are required as the drier is free standing on leveled floor Cleaning doors giving access to plenum chambers and radiators are also supplied as standard.