Manometric temperature measurement

Milton et al. [1.136] used this methods and refer to it as manometric temperature measurement. They used times of pressure rises of up to 30 s. During this time, the ice temperature will increase, mainly due to continued heat flow. Therefore, an equation has been developed to transform the experimental pressure data, including three other corrections, into the true vapor pressure of the ice. If the valve is closed for only a very short time, < 3 s, and the pressure is measured and documented 60 to 100 times/s, these data can be recorded as shown in Fig. 1.78.1. The automatic pressure rise measurements (1) can then be plotted... 

Milton et al. [1.136] used this method and referred to it as manometric temperature measurement. They used times of pressure rise of up to 30 s. During this time, the... 

N. Milton, M. J. Pikal, M. L. Roy, and S. L. Nail, Evaluation of manometric temperature measurement as a method of monitoring product temperature during lyophilization. J. Pharm. Sci. Technol. 5/. 7-16 (1997). 

Fig. 6 Calculated contributions to the pressure rise in a manometric temperature measurement experiment. Calculations were made for a typical product with an initial ice temperature of —20°C, corresponding to an initial vapor pressure of 775mTorr. Open circles = effect 1, sublimation open triangles = effect 2, dissipation of temperature gradient open squares = effect 3, heat flow from shelf to product filled circles = sum of all effects. (Adapted from Ref...

MDSC modulated scanning microscopy MTM manometric temperature measurement NMR nuclear magnetic resonance PAR pressure rise analysis US ultrasound... 

Milton et al. (1997) proposed the manometric temperature measurement (MTM) the transient pressure response is mathematically modeled under the assumption that four mechanisms contribute to the pressure rise, namely the direct sublimation of ice through the dried product layer at a constant temperature, the increase in the ice temperature due to continuous heating of the frozen matrix during the measurement, the increase in the temperature at the sublimation interface when a stationary temperature profile is obtained in the frozen layer and, finally, the leaks in the chamber. The four contributions are considered purely additive the values of the thickness and of the thermal gradient are needed but they are not known exactly. The values of the vapor pressure over ice, of the product resistance and the heat transfer coefficient at the vial bottom are determined with regression analysis. 

Gieseler, H., Kramer, T, Pikal, M. J., 2007b. Use of Manometric Temperature Measurement (MTM) and SMART Freeze Dryer technology for development of an optimized freeze-drying cycle. J. Pharm. Sci. 96 3402-3418. 

Pikal, M. J., Tang, X., Nad, S. L, 2005. Automated process control using manometric temperature measurement United States Patent No. 6971187 Bl. 

Velardi, S. A., Rasetto, V., Barresi, A. A., 2008. Dynamic Parameters Estimation Method advanced Manometric Temperature Measurement approach for freeze-drying... 

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