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Tall Form Spray Dryer and Chiller

The FT80 Tall Form Spray Dryer and FT81 Spray Chiller are purpose designed to allow laboratory quantities of products to be processed. Despite the small-scale, the powders produced will be comparable to large-scale production.

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FT80/FT81

MINIATURE-SCALE R&D TECHNOLOGY
FT80/FT81 Tall Form Spray Dryer and Chiller - Issue 11

The Armfield FT80 Tall Form Spray Dryer and FT81 Spray Chiller have been purpose designed to allow laboratory quantities of products to be processed. Despite the small-scale of the equipment, the powders produced will be comparable to large-scale production dryer capability. Both systems offer unparalleled flexibility with separate, individually controlled inlet and outlet fans, together with variable nozzle positions and selection of co- or counter-current flow configurations. This flexibility is enhanced by an unsurpassed range of options, purpose designed for laboratory and research use.

With the appropriate accessories it is possible to change from spray drying to spray chilling configurations in a matter of minutes, thus adding further unique experimental capability.

Armfield - FT80 Profile - FINAL from Armfield Ltd on Vimeo.

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Features

  • Accessory sets are available to quickly change from drying to spray chilling
  • Available as a Spray Dryer (FT80) or as a Spray Chiller (FT81)
  • Drying air temperature up to 250°C
  • Maximum flow rate up to 7 l/hr
  • Maximum evaporation rate of 3 l/hr
  • Tall form chamber straight side to diameter ratio of 3:1, conical discharge section
  • Advanced two-fluid nozzle atomisation system
  • Supplied with optional nozzle configurations for counter- and co-current atomising
  • Individual inlet and exhaust fans with variable-speed control
  • Bag filter and trace heating options
  • Flexible controls and full instrumentation provided in the IP65 control console
  • Easily dismantled for inspection and cleaning purposes
  • Compact, mobile design
  • Data logging facility for all key operating parameters
  • Powder discharges from two points, chamber and cyclone
  • Low noise levels
  • Control and measurement of relative humidity
  • Spark arrester on input and enhanced safety extraction fan

Benefits

  • No clogging, no need for de-blocking devices
  • Co-current flow for drying heat sensitive products
  • Counter-current flow maximises chamber residence time for non-heat sensitive products
  • Residence times in the drying cylinder variable up to 9 seconds
  • Easy connections to electrical and compressed air utilities
  • Data recording to computer for rapid evaluation and comparison

Process Description

Co-current spray-drying configuration

The liquid to be dried is pumped to the top of the drying chamber by a variable-speed progressing cavity pump, which provides a very smooth flow and constant flow rate. It is atomised by a two-fluid nozzle and enters the drying chamber as a fine droplet dispersion.

Hot air is blown into the chamber, on to the droplets causing flash evaporation of the surface moisture.

The bound moisture in the particles is evaporated in the time that they fall to the discharge point at the base of the cone (the residence time). In this configuration the particle temperature will never exceed the wet bulb temperature of the exhaust air.

A variable-speed centrifugal fan provides control over the inlet air flow and a steady inlet temperature is achieved by using a three-term controller in conjunction with an electric heater. A second variable-speed fan draws air from the chamber through a cyclone separator. This ‘push-pull’ fan system provides flexibility to operate the chamber at variable pressures with variable residence times.

Two powder collection points are provided, one at the bottom of the main chamber, and one on the cyclone separator. This enables particles of different sizes to be collected simultaneously and/or separately.

Exhaust-air relative humidity can be measured and controlled so as to enable the system to run at the required RH level.

The nozzle is an external-mix two-fluid atomising nozzle. Compressed air is directed onto the liquid stream as it leaves the nozzle body and immediately atomises it. With this type of nozzle the orifice is larger than a single fluid type, and so it is possible to atomise more viscous products and even products containing suspended solids.

Counter-current spray-drying configuration

The FT80 Tall Form Spray Dryer is supplied as standard with two nozzles and nozzle hoses, one for co-current and one for counter-current. In counter-current configuration the nozzle is positioned at the bottom of the chamber and sprayed upward into the flow of hot air.

The FT80 Tall Form Spray Dryer

FT80-60 Fluid Bed Cooler Accessory 

An optional accessory is available to provide final cooling of the spray dried powder in a fluidised bed. This feature is particularly useful when drying powders containing fats as the fluid bed helps to crystallise the fat content. Typical applications include infant formulas and whole milk powders.

Spray Chiller Configuration

For spray chilling the flow of air from the inlet fan to the spray chamber is chilled instead of heated. The air is cooled using chilled water and a stainless steel heat exchanger. The FT81 Tall Form Spray Chiller is supplied complete with its own refrigeration unit. Counter-current configuration is normally used for spray chilling.

Note: Many spray chilling applications also require the Trace Heating Accessory, FT81-65.

FT80-70, FT81-70 Bag Filter Accessory 

The Bag Filter accessory is used on the exhaust air outlet. The five micron filter removes virtually all of the remaining product dust in the airstream, resulting in clean air that can then be discharged directly into the working area, without requiring further treatment, ducting or extraction fans. (This filter is not designed to extract toxic or hazardous materials).

FT81-65 Trace Heating Accessory 

The trace heating accessory is required when the product must be kept above a certain minimum temperature prior to atomisation in the spray nozzle.

It comprises a heater band on the feed vessel, a heater on the pump body and a further heater on each of the spray nozzles. The trace heating controls are enclosed in a separate mains powered stainless steel box, which can be positioned on the main control unit. Two independent temperature controllers are used for the feed vessel wall temperature and the nozzle body temperature. Although primarily required for spray chilling, this accessory can also be used with the spray drier.

Note: The trace heating is not designed to heat the product, but to maintain the product at an elevated temperature.

Applications

  • Milk powders
  • Encapsulation
  • Natural food flavours
  • Sucrose solutions
  • Infant formulas
  • Whey proteins
  • Fruit flavour formulations
  • Fat formulations

Ordering Codes

FT80 Tall Form Spray Dryer
FT80-A: Tall Form Spray Dryer: 220-240V/1ph/50Hz*
FT80-G: Tall Form Spray Dryer: 220-240V/1ph/60Hz* (* Max 35A)

FT81 Tall Form Spray Chiller
FT81-A: Tall Form Spray Chiller: 220-240V/1ph/50Hz
FT81-G: Tall Form Spray Chiller: 220-240V/1ph/60Hz

Optional Accessories

FT80 Tall Form Spray Dryer

FT80-25-A: Spray Chilling Accessory: 220-240V/1ph/50Hz
FT80-25-G: Spray Chilling Accessory: 220-240V/1ph/60Hz
(Containing all items required to convert an FT80 spray dryer into an FT81 spray chiller)
FT80-60: Fluid Bed Cooler Accessory
FT80-70: Bag Filter Accessory
FT80-DTA-ALITE: Data Logging System

FT81 Tall Form Spray Chiller

FT81-70: Bag Filter Accessory
FT81-DTA-ALITE: Data Logging System
FT81-65-A: Trace Heating Accessory: 220-240V/1ph/50Hz
FT81-65-G: Trace Heating Accessory: 220-240V/1ph/60Hz

Unit Specification

General

Liquid feed:
2-7 l/h from variable-speed progressive cavity pump 
Air flow: Up to 30scfm, using variable-speed fans in ‘push-pull’ configuration 
Chamber residence times: Variable up to 9 seconds 
Powder collection points: Separate chamber and cyclone discharge points 
Atomisation nozzles: 2-fluid type

Spray drying

Electric air heater:
4.5kW
Drying air temperature: 50-250°C
Evaporation rates: 1.5-3 l/h
Typical particle size range: 20 - 120 microns

Spray chilling

Air temperature:
2°C minimum
(Note: not all parameters are necessarily achievable simultaneously)

Windows Data Logging Systems

A unique benefit of the Armfield miniature-scale food processing range is that the measured data may be captured and stored to disk.

An Armfield FT80-DTA-ALITE Data Logging Accessory transfers results to a PC. Temperatures, pressures and relative humidity can be monitored in realtime. The data can be displayed in graphical and tabular forms and printed. The user needs a computer with a spare USB port, running Windows 98 or later.

Requirements

Compressed air supply
1-5 bar pressure, 0.05 m3/min

Shipping Specification

FT80 Tall Form Spray Dryer
Volume: 3.2m3
Gross weight: 300kg

FT81 Tall Form Spray Chiller
Volume: 4.0m3
Gross weight: 450kg

Overall Dimensions

FT80 Tall Form Spray Dryer
Height: 1.70m
Width: 1.30m
Depth: 0.62m

FT81 Tall Form Spray Chiller
Height: 1.70m
Width: 1.80m
Depth: 0.80m