Drying process course

The richer a plant part is in nutrients and the slower the drying process, the higher the bacterial count of the resulting drug root drugs, which of course are to begin with more heavily contaminated, always have a higher bacterial count than do flowers, for example, which are a less suitable as a nutrient medium. 

Fig. 1.62. Course of a freeze drying process in a plant, as shown in Fig. 1.65. Pressure control during MD is not activated. 1.0 kg product in four aluminum trays with machined bottoms, Tsh after evacuation controlled at +29 °C, d = 0,6 cm.

Fig. 1.69. Course of a freeze drying process during which Tke has not been kept constant at -26.8 °C. To avoid the declining temperature, either Tsh could have been increased after 2 h (difficult to control, the inertia of the heating system is substantial) or pc increased until Tkt is constant at -26,8 °C. 1, pch (TM) 2, pch (CA) 3, Tpt (RTD) 4, Tke (BTM) 5, end of pressure control.

Therefore, it is decisive for the freeze drying process which follows that the filled vials during this time pass through a known and reproducible course of temperature. The prod-... 

The merit of Malinin s work is the comparative study of water content of bones by reproducible methods. The measurement of water vapor pressure during the drying cannot be used dirctly to determine the RM, as Malinin correctly states. Measurement of the description rates (DR) provide a means to follow quantitatively the course of desorption drying. The method is described in Section 1.2.2, but cannot be applied in an installation used by Malinin because the condenser cannot be separated from the chamber by a valve. By using the data given in the paper of Malinin it is possible to estimate the freeze drying process of bone transplants as follows ... 

In Section 2.2.8, possible failures during the freeze drying process are classified in four categories, and the preventions and necessary actions briefly discussed. In this chapter, some unexpected or undesirable events are studied which, by experience may happen. The problems listed here are selected from the course of the freeze drying process. A breakdown of single components, for example pumps, compressors or valves are not included in this chapter. The list will be incomplete, but an attempt has been made to mention some of the more frequent events. The problems with leaks and their hunting is discussed in Section 2.2.8. 

Figure 58A-C shows that the heat source promoting the drying process changes during the course of the batch combustion. At times to and ti there is an artificial heat source located in the over-bed section. At time t2 the flaming combustion has started. The flames feed back heat to the bed by means of radiation. At time t3 the basic heat flow comes from the char combustion and the ignition front, by means of conduction and radiation. [12,24]...

With the aid of this approximate equation, the drying characteristics of many substances can be assessed. If K and q have been determined for various temperatures and vrater vapor partial pressures, the values for other temperatures are easily interpolated, so that the course of the drying process can be calculated under all operating conditions. With the aid of a similarity transformation, one can further compare the course of drying process of a material w/ith knovm properties w/ith that of a material w/ith different properties. 

Fig. 1.56.2. Course of a freeze-drying process. 1, Precooling of the shelves 2, freezing of the product 3, evacuation and main drying (MD) 4, secondary drying (SD) 5, changeover from MD to SD sh raised to maximum tolerable product temperature 6, Tjce measurements by BTM 7, temperature sensors RTD in the product 8, temperature sensors Th in the product 9, temperature of the shelves (T h) 10, ice condenser temperature ...

Fig. 1.63. Course of a freeze-drying process in a plant as shown in Figure 1.66. Pressure control not activated. 2.4 kg of product in three welded stainless-steel trays with flattened bot-...

In most cases, the solvent must be removed from the polymer. After polymerization is complete, either the product is precipitated from the solution or the solvent is distilled off. With precipitation polymerizations the separation is automatic. Residual solvents, of course, must always be removed, mostly by a suitable drying process. 

In the case of salami, starter cultures can be cultivated on meat substrate and freeze-dried, where they remain active at a large rate. The storable culture substrate is added to the salami raw mixture to start the desired ripening process. Depending on process course, it can already contain flavour or flavour-precursors which contribute to accelerating the ripening process. 

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