The Hilton H694 Fluidisation & Fluid Bed Heat Transfer Unit has been designed to provide visual and quantitative results related to the flow of air through both a packed and fluidised bed of granular material contained in a vertical glass cylinder. At the lower end of this is a distribution chamber and air distributor which supports the bed when defluidised. Probes for temperature and pressure measurement, and a horizontal cylindrical heater, can all be moved vertically to any level in the bed chamber. Air from a local compressed air supply is delivered through a filter/pressure regulator, an air flow meter fitted with a control valve and an orifice plate (to measure higher flow rates), to the distribution chamber.
When in use, the heat transfer rate from the heater is adjusted by a manual electronic control, and digitally displayed. Two thermocouples are embedded in the surface of the element. One of these indicates the surface temperature, and the other, in conjunction with a controller, prevents the heater surface temperature exceeding a set value (up to 200°C). A digital temperature indicator with a selector displays the temperatures of the element, the air supplied to the distributor, and the moveable probe in the bed chamber.
Two liquid filled manometers are fitted. One displays the pressure of the air at any level in the bed chamber, and the other displays the orifice differential pressure, from which the higher air flow rates can be determined. Four grades of Fused Alumina (Aluminium Oxide) Loose Grain are supplied with the unit and these are suitable for a wide range of fluidisation and heat transfer experiments.
An important feature of this unit is the ease with which the bed material may be changed. The unit can be in operation again in two or three minutes.
