Principle of Operation

A nickel plated copper platen is electronically cooled at one end and warmed at the other end. Air or nitrogen is caused to flow over the surface, from cool end to warm end as a uniform blanket. To achieve the required degree of uniformity the air or gas is delivered via a carefully designed sintered distribution block; the design is such that freezing does not take place at the inlet.
For use with air, a drying system is incorporated into the housing together with a flow controller. The air dryer contains indicator crystals, which are clearly visible in a transparent container. The complete air conditioning system is readily accessible at the side of the instrument.
Water at normal mains pressure removes the excess heat from the coolers. Quick release couplings are provided. Water is normally drawn from a laboratory tap and the outlet is run to drain by gravity. Alarms, both audible and visual are actuated in the event of cooling water supply failure.
Temperature sensors are mounted under the surface of the platen. These are used to control the temperature of the platen in accordance with the chosen range. They are also used in conjunction with the temperature cursor to indicate the platen temperature at the MFFT point.
A hinged clear plastic cover over the platen provides thermal insulation whilst allowing visual inspection of the determination as it progresses. The transparent temperature cursor is mounted on the cover to identify the exact film forming temperature.