Name of the equipment
Armfield UOP8-MKII-Tray Drier
Brand
Armfield UOP8-MKII-A
Description
Armfield UOP8-MKII Tray Drier is a small-scale benchtop tray dryer that dries solids by passing a stream of hot air over trays of wet material, a method commonly used in industry. It comprises a square air duct fabricated from stainless steel. Air is drawn into the duct through a mesh guard and flow damper by an axial flow fan. The fan speed can be controlled to produce a range of air velocities in the duct. The air passes over an electrically heated element with electronic closed-loop control, which provides stable air temperatures at the user-selected value. A tray carrier is located in the central section of the duct, which can hold up to three trays of material to be dried. The trays are made with three lightweight coated aluminium and are suitable for food applications. The trays are inserted or removed from the duct through a latched side door with an acrylic panel for viewing purposes. The total weight of the trays and the carrier is measured using three load cells and is displayed on the software. A graph of weight against time allows the drying regimes to be displayed and understood. From the rate of change (slope) of this graph the drying rate can be determined.
Comprehensive instrumentation is included and the measured values recorded on the computer:
- Weight of trays plus contents (with tare function)
- Temperature (dry bulb) and relative humidity of the heated air before the trays
- Temperature and relative humidity of the air after passing over the trays
- Air velocity
From each pair of temperature and relative humidity readings the full thermodynamic properties of the air can be determined using a psychrometric chart, i.e. the wet bulb temperature, the moisture content and the changes in enthalpy. This allows for a more in-depth analysis for project or research work, for example comparing the change in moisture content of the air with the rate of moisture loss from the trays.
Specification
- Computer control of temperature and air flow rate, with sophisticated data logging and analysis software
- Capacity: up to 2.1kg of wet material
- Flow rates 0.4 to 3.0 m/s over trays
- Temperatures up to 80°C at 0.4 m/s (less at higher flows)
- Integrated electronic weight measurement to determine drying rate
- Electronic measurement of temperature and humidity before and after the drying trays
- Electronic measurement of air flow
Applications
It is applicable to the unit operations laboratory and also to food technology education and research. This instrument able to demonstrate:
- Drying rate regimes
- Heat and mass transfer
- Drying tests on solids for industrial use
- Effect of temperature and air velocity on drying rates
- Use of psychrometric charts
Contact information
Equipment-in-charge: Miss Fung Lok Wan, Lolita
Email: lok-wan.fung@polyu.edu.hk
Office: TU305
