On the Design of an In-Line Control System for a Vial Freeze-Drying Process: The Role of Chamber Pressure

2009 ◽  
Vol 4 (2) ◽  
Author(s):  
Davide Fissore ◽  
Roberto Pisano ◽  
Antonello A. Barresi
Keyword(s):  
Control System ◽  
Freeze Drying ◽  
Pressure Rise ◽  
Open Loop ◽  
Parameters Estimation ◽  
Chamber Pressure ◽  
Fluid Temperature ◽  
Drying Process ◽  
Product Temperature ◽  
Drying Chamber

This paper is focused on the design of an in-line control system for the freeze-drying process of pharmaceuticals in a vial. The goal is to minimize the duration of the primary drying, when most of the water is removed by sublimation while maintaining the product temperature below the maximum value allowed by the product. The pressure in the drying chamber and the temperature of the fluid that is used to heat (or to cool) the product can be manipulated; the pressure rise test and the DPE (Dynamic Parameters Estimation) algorithm are used to estimate the product temperature and the residual ice fraction, i.e. the controlled variables. Both an open-loop controller, using constant values of fluid temperature and chamber pressure, and a closed-loop controller, based on the in-line optimization of the fluid temperature, will be described and tested. Finally, the possibility of manipulating in-line the pressure in the drying chamber will be discussed.

Development of a Compact Vacuum Freeze Drying for Jelly Fish (Schypomedusae)

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
M. Idrus Alhamid ◽  
M. Yulianto ◽  
Nasruddin M. ◽  
Engkos A. Kosasih
Keyword(s):  
Heat Loss ◽  
Freeze Drying ◽  
Moisture Ratio ◽  
Cold Trap ◽  
Chamber Pressure ◽  
Internal Cooling ◽  
Drying Process ◽  
Drying Time ◽  
Chamber Temperature ◽  
Drying Chamber

A new design of a vacuum freeze drying with internal cooling and heater from condenser’s heat loss was built and tested. The dryer was used to dry jelly fish (scyphomedusae) to study the effect of drying parameter such as temperature within the drying chamber on mass losses (evaporation) during freezing stage and moisture ratio at the end of drying process and also the drying rate of vacuum drying process. The cold trap temperature rise in when activated the heating from condenser’s heat loss. The midili thin layer mathematical drying model was used to estimate and predict the moisture ratio curve base on different drying chamber temperature. The result of this experiment show that mass loss during freezing stage decreased with a decrease in drying chamber temperature with constant pressure. Drying time reduced with an increase in drying temperature. Drying chamber temperature decreasing has a result pressure saturation of material lower than drying chamber pressure have an effect mass transfer should not occurs.

Parameter Optimization of Vacuum Freeze-Drying Processing on Tan Lamb

2014 ◽  
Vol 513-517 ◽  
pp. 4281-4284
Author(s):  
Chen Ji ◽  
Yan Li Fan ◽  
Gui Shan Liu ◽  
Wei Wang ◽  
Rui Ming Luo
Keyword(s):  
Freeze Drying ◽  
Orthogonal Design ◽  
Chamber Pressure ◽  
Drying Process ◽  
Quadratic Regression ◽  
Plate Temperature ◽  
Drying Time ◽  
Material Thickness ◽  
Heating Plate ◽  
Drying Chamber

In this paper, the effects of drying chamber pressure, heating plate temperature and material thickness on the drying time of Tan lamb in vacuum freeze-drying process were studied using quadratic regression orthogonal design. The results showed that the drying time was significantly affected by drying chamber pressure, heating plate temperature and material thickness as well as the interaction of heating plate temperature and material thickness. The optimized parameters were drying chamber pressure 27.9 Pa, heating plate temperature 47.9°C and material thickness 4.3 mm. On these parameters, the drying time was 4.3 h.

Effect of Hot Air Reservoir and Insulator Tray in the Development of Vacuum Freeze Drying

2013 ◽  
Vol 388 ◽  
pp. 139-145
Author(s):  
Muhammad Idrus Alhamid ◽  
Nasruddin ◽  
Engkos A. Kosasih ◽  
Muhamad Yulianto
Keyword(s):  
Triple Point ◽  
Freeze Drying ◽  
Pressure Rise ◽  
Vacuum Pump ◽  
Chamber Pressure ◽  
Drying Process ◽  
Constant Weight ◽  
Hot Air ◽  
Freeze Dried ◽  
Point Condition

The Objective of this work is to know effect of inserting hot air from reservoir to the process of vacuum freeze drying. Tentacle of jelly fish as sample with constant weight 50 g and placed at insulator and teflon container which isolated, the samples were freeze dried with condition at experiment varying between inserting and without inserting hot air at temperature 27°C and also heating from heat loss condenser. The result of experiment shows that while inserting hot air into vacuum freeze drying make pressure rise in until pressure reach 40 mbar. And this phenomena make material evaporation and this event cant be done in vacuum freeze drying. And when without hot air reservoir the pressure can reach 3.5 mbar and the subimation can be done in this process. Vacuum freeze drying process without hot air reservoir need time 12.5 hours and for vacuum freeze drying with hot air reservoir need time 11 hour to drying 50 g of jelly fish tentacle. For process with insulator tray the material can be done in 22,7 hour with internal freezing. From this experiment can be concluded that for vacuum freeze drying with inserting hot air need more ability of vacuum pump specially in flowrate and ultimate vacuum to keep the chamber pressure below triple point condition.

scholarly journals Freeze-drying and its application to some Finnish agricultural products

1985 ◽  
Vol 57 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Yrjö Roos ◽  
Jorma J. Laine
Keyword(s):  
Moisture Content ◽  
Freeze Drying ◽  
Nitrogen Atmosphere ◽  
Agricultural Products ◽  
Drying Process ◽  
Sublimation Rate ◽  
Freeze Dried ◽  
Being There ◽  
Drying Chamber ◽  
Maximum Surface Temperature

This study deals with the freeze-drying of berries, vegetables, roots and pork produced in Finland. The products were freeze dried whole, in slices or cubes. The pressure in the drying chamber was 10—20 Pa and the maximum surface temperature +23—+ 40°C. The products were packed after freeze-drying into glass jars under air and in polyester-aluminium-polyethene foil under vacuum or nitrogen atmosphere. The drying temperatures and drying times were measured. During storage for 4 months, the differences in quality were evaluated. The drying times ranged from 8 to 25 hours. The moisture content of the dry products was 1—3 %. The sublimation rate at the beginning of the drying process was very rapid, being there after constant. Bilberries, carrots and radishes collapsed during drying. Most of the products dried moistened and underwent aroma changes during storage in glass jars under air. The products packed under vacuum or nitrogen atmosphere proved stable.

scholarly journals On the Methods Based on the Pressure Rise Test for Monitoring a Freeze-Drying Process

2010 ◽  
Vol 29 (1) ◽  
pp. 73-90 ◽  
Author(s):  
Davide Fissore ◽  
Roberto Pisano ◽  
Antonello A. Barresi
Keyword(s):  
Freeze Drying ◽  
Pressure Rise ◽  
Drying Process

Video real-time imaging of artificial membranes during freeze-drying by cryo-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 16-17
Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price
Keyword(s):  
Real Time ◽  
Self Assembly ◽  
Freeze Drying ◽  
Video Capture ◽  
Drying Process ◽  
Artificial Membranes ◽  
The Past ◽  
Cryo Electron Microscopy ◽  
Spherical Structures ◽  
Capture Techniques

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.

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