Rice hull-fired dryer for natural sausage casing

Placino et al. (SLSU), developed a prototype rice hull-fired dryer and assessed its performance under normal, dry, and wet conditions to produce bacteria-free and high quality natural langgonisa skins at an affordable cost. Five hundred grams of clean raw intestines were tested for drying. The drying bin's temperature was set at 45 deg C. The moisture content of wet feed was 72% and the drying time was 2.5 hours. The machine was fabricated in the University's Machine Shop using locally available materials and expertise. The study was conducted from June to October 2006. The dryer was fabricated with three major parts: the furnace, the air heater, and the drying bin. The furnaces of Maligaya Rice Hull Stove and Lo-Trau Rice Hull Cooker were modified by producing additional air for complete combustion. The air heater used was a closed type heat exchanger. Coiled pipe was enclosed in the air heater. Raw small intestine hanged inside the drying bin were dried through convection mode of heat transfer. Heated air was generated by forcing outside air to pass through the heated coil. Findings of the study revealed the following: Summary of computed data showed that the resulting weight of the dried product at different treatments varied with respect to the temperature of the surrounding air supply. With an air supply of 30.97 deg C at normal condition, the resulting final weight was 164.04 g, 156.96 g at 36.60 deg C, and 163.10 g at 27.00 deg C for dry and wet conditions. The amount of moisture removed were 14.16%, 10.60%, and 14.60% for normal, dry and wet conditions, respectively. There was little differences in terms of the average amount of rice hull fuel used (4.47 kg, 4.23 kg, and 4.07 kg at normal, dry and wet conditions. The modified models of the Maligaya Rice Hull Stove and Lo-Trau Rice Hull Cooker were effective as they showed consistent performance at different test conditions. Compared with sundrying, the resulting dried product using the mechanical convection type dryer was cleaner and the drying time was shorter (2.5 hours). Sundrying normally takes a day. It was recommended that a follow-up test can be conducted to validate the efficiency of the dryer. Nonetheless, the dryer can be tried by local manufacturers. It can also be tested for other agricultural products.