McCLOY Fluid Bed drier is the only true Fluid Bed drier in the world today
Air flow and temperatures are carefully selected to ensure a satisfactory temperature gradient thus ensuring highest quality tea
The aerodynamic design of the drying chamber maintains correct velocity and pressure throughout the length of the bed thus ensuring perfect fluidization
All contact parts with tea are made of high quality food grade stainless steel
Efficient on steam consumption approximately 2.5 – 3kg of steam per kg of made tea
Fully automatic control with help of control panel
Operator friendly with negligible maintenance cost
Environment friendly and hygienic – No fly – off
Available in 2 stage and 3 stage with output varying from 250 kgs/hr to 1000 kgs/hr
When an air flow is introduced through the bottom of a perforated bed of solid particles, it will move
upwards through the bed via the empty spaces between the particles. At low air velocities, aerodynamic drag on each particle is also low and thus the bed remains in a fixed state. Increasing the velocity, the aerodynamic drag forces will begin to counter the gravitational forces, causing the bed to expand in volume as the particles move away from each other. Increasing the velocity further, a value will be reached a critical velocity in which the upward drag forces are equal to the downward gravitational forces and hence causing the particles to become suspended within the fluid. At this critical velocity value, the bed is said to be fluidized and will exhibit fluidic behavior By further increasing air velocity, the bulk density of the bed will continue to decrease and its fluidization becomes more violent and agitated until the particles no longer form a bed and bumble upwards by the air flow. This phenomenon is called Fluidization and is the principle J F McCloy Ltd has developed in the design of drier models of B/450/2, B/600/3 and B/850/3
The advantages of the fluidized drying are many and include, easy to control and automate, rapid mixing between the particles being dried and the fluidizing fluid, resulting to very high heat and mass transfer rates and hence high rate of water extraction i:e drying. Air flow and temperatures are carefully selected to ensure a satisfactory temperature gradient thus ensuring highest quality teas as proved by higher prices obtained on the Mombasa Tea Auction by factories using McCloy driers.
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.
Manometers for each plenum chamber
Digital Temperature control panel with alarm.
All electrical controls are mounted in a single control panel supplied as standard.
An internal flood light is fitted onto the hood exit to facilitate monitoring of the drying process.