Design and Construction of a Lyophilizer system using locally available material

Abstract

A lyophilizer system was designed and constructed with a galvanized metal sheet to reduce the cost and to make it available to local and poor food processors. It consists of 330.2 mm x 508 mm x 457.2 mm rectangular shaped chamber with the inner and outer layer reinforced with a hollow mild steel square pipe of 17 x 1.7 mm to prevent implosion of the lyophilizer during dehydration phase. The system was designed based on the specific heat capacity of Pears, Tomatoes and Carrot with values of 3.62 kJ/kg C, 3.98 kJ/kg C and 3.79 k/kg C respectively. The results showed that dry-bulb temperature of 28°C at initial stage and 1°C after drying while the dew point temperature of 20.8°C at initial stage and -6.1°C after drying were recorded. The result obtained also shows that the temperatures (dry-bulb and dew point) and relative humidity of the lyophilized product is lower as compared to the imported ones. A total of 6hours was used for freeze drying with 1/10 reduction in weight of the lyophililized product when weighed.