H4-VV-28-D ominal output torque Nm Nm Flender GmbH Mot Helical gearbox H4

Flender/Flender Gear Units/Helical gearbox H4

ghter in weight and have lower transportation Packaging of Fruits and Vegetables 5 costs. Textile containers, .., jute sacks, are also used sparingly for the bulk transportation of fruits and vegetables to market. Although jute sacks are durable and have high tearresistance, they have low extensibility, they are very poor barriers to moisture and gases,and they are subject to mold spoilage. They are also being replaced by multiwall papersacks. 4.2 Paper and Board Paper and board are still very popular packaging materials in North America. Kelsey ( estimated that paper and paperboard packaging constitutes about 3% of the ap-proximately 7 million tons of paper products produced annually with market value of approximately $1 billion. Paper pulp is produced from wood chips by acid or alkaline hydrolysis. The pulp is suspended in water and beaten with rotating impellers and knives to split the cellulosebers longitudinally. The bers are then rened and passed through heated rollers to reducethe moisture content, and then through nishing rollers to give the nal surface propertiesto the paper. Alkaline hydrolysis produces sulfate pulp, and acid hydrolysis producessulte pulp. The various types of paper and paperboard containers used as food packaging are shown in Table 1. Kraft paper is made from at least 8% sulfate wood pulp. It is very strong paper, which is used to make grocery bags, multiwall bags, shipping sacks, and specialty bagsthat require both economy and strength for bulk packaging of powders, our, sugar, fruits, and vegetables. Bleached papers are more expensive and weaker than unbleached andhave excellent printability. Vegetable parchment is produced from sulfate pulp that is passed through bath of sulfuric acid. It has more intact surface than kraft paper and therefore has greater grease resistance and wet strength properties than kraft paper. Table 1 Types of Paper Commonly Used as Packaging Material Product Characteristics Example Kraft paper Brown, unbl