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A drum is a cylindrical container used for shipping bulk cargo. Drums can be made of steel, dense paperboard (commonly called a fiber drum), or plastics, and are generally used for the transportation and storage of liquids and powders. Drums are often certified for shipment of dangerous goods. Shipped goods must be matched with the make of drum necessary to comply with applicable regulations. Drums are also called barrels in common usage. ==Background== It is common to hear a drum referred to as a barrel and the two terms are used nearly interchangeably. Many drums have a common nominal volume of and nominally measure just under tall with a diameter just under and differ by holding about thirteen gallons more than a barrel of crude oil. In the United States, drums are also in common use and have the same height. This allows easy stacking of mixed pallets. Barrels can be constructed of plastic, laminated paperboard or steel. The two common sub-types of drums are the open top and the welded top (with NPS bung holes). The latter are almost universally called "barrels" in preference to ''drums'' in the United States. They cannot efficaciously either dispense or be filled with powdered goods, though they might ''store'' them very well, so are not used for such goods, being reserved for liquids transport and storage. Plastic drums are manufactured using injection blow moulding technology and have either a separate lid (similar to those on fiber drums) or a welded type top with the bung holes molded in. Metal drums are manufactured with cold-rolled steel sheets, welded themselves into long pipe-like sections then ''forged'' on a stamping press into drum bodies. A rolled seam is then made for the drum bottom, or bottom and top both. Some drums have reinforcing rings of thickened metal or plastic, called "chines", at four places: top, bottom, and one each a third of the way from each end ring. This sufficiently strengthens them so that they can readily be turned on their sides and rolled when filled with heavy materials, like liquids. Over short to medium distances, drums can be tipped and rolled on the bottom rim while being held at an angle, balanced, and rotated with a two-handed top grip that also supplies the torque (rotational or rolling force). The open-top sub-type is sealed by a mechanical ring clamp (concave inwards) that exerts sufficient pressure to hold many non-volatile liquids and make an airtight seal against a gasket, as it exerts force inward and downward when tightened by a normal three-quarter inch wrench or ratchet wrench. Tops exist with bung holes as above, and these hybrid drums with lid can be used to ship many non-volatile liquids as well as industrial powders. Many drums are used to ship and store powdered products as well as liquids, such as plastic beads for injection moulding, extrusion, and purified industrial grade powders like cleansers (e.g., fertilizers, and powdered aluminum). If used to transport dangerous goods across international boundaries, they may need to have UN certification. In general, drum usage is limited to wholesale distribution of bulk products, which are then further processed or sub-divided in a factory. These metal drums have two openings with flanges (2 in NPS and ¾ in NPS). Once the drums are filled, the plugs (bungs) are screwed in the flanges using pneumatic or hand operated bung tightener (plug wrench). To secure the contents of the drums against theft and adulteration during shipment, cap-seals made of metal and other types like metal-plastic laminates are used. These cap-seals sit on top of the flanges and are crimped, using a drum cap-seal crimping tool, also called a drum cap sealer. Once cap-seals are crimped, the plugs can be unscrewed only by breaking these cap-seals. Pneumatic and hand-operated cap-seal crimping tools are available. Pneumatic ones are used in production lines for high production. The fiber drums referred to above will easily hold , and are usually coated internally with a urethane or plastic protective coating. They have steel reinforcement rims at their ends, and are sufficiently strong that this is the only type of drum that is not reinforced in the middle third, but that is almost certainly due to the difficulty in creating a "vee" rib in a paper layer that essentially spirals out from a single end seam. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Drum (container)」の詳細全文を読む スポンサード リンク
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