The Model 271 calorimeter pre-heater uses the temperature control technology developed for

the 200 series calorimeters. This technology enables up to four canisters to be preheated prior

to measurements being made in a calorimeter. Each of the preheater cells can be set to a differ-

ent temperature enabling use with multiple calorimeters.

During normal measurements a calorimeter is subject to large temperature changes when a

new "cold" canister is inserted. This increases the measurement time and is due to the mass of

both the calorimeter and canister having to reach thermal equilibrium. Preheating enables this

equilibrium to be achieved in the pre-heater rather than the calorimeter. Measurement time is

reduced as the calorimeter measurement chamber does not need to re-established thermal equi-

Note that the sample preheating and sample end point power prediction cannot be employed

together. Prediction is most effective when only one sample is available at a time for measure-

ment. Measurement time is reduced in this case is due to the early declaration of a predicted

end point sample power.

Sample preheating is most effective when multiple samples are available for measurement at

the same time. Each sample canister reaches the calorimeter equilibrium temperature profile

while in the preheater. When such a preheated sample canister is rapidly transferred to a calo-

rimeter measurement chamber, the calorimeter reached thermal equilibrium in a considerably

shorter time than would be the case for an unpreheated canister.

Each of the four preheater cells is similar to a two stage calorimeter offering high stability tem-

perature control. The instrumentation scans each cell and provides the necessary power to

maintain temperature stability.

If the thermal disturbance during canister transfers is small, calorimeter measurement times as

short as 30 minutes are possible.

Four preheating cells each independ-

Reduces calorimeter measurement

·

·

ently controlled

times by 50% or more.

Unit is mounted on a single trolley

·

Sample canister pre-conditioner com-

·

and connected to an instrument rack

patible with ANTECH calorimeter

by multi-core cables

Model 261 Series R,P and Q for both

Pu and Tritium measurements (also

Weight of trolley mounted version is

·

available for other Calorimeter mod-

Power consumption 1000 watts maxi-

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