U blades: Curved bulldozer blades designed to increase moving capacity of tractor equipment.
U bolt: A U-shaped bolt with threads at the ends of both arms to receive nuts.
U-bend die: A die with a square or rectangular cross section which provides two edges over which metal can be drawn.
U-shaped abutment: A bridge abutment with wings perpendicular to the face which act as counterforts, a very stable abutment, often used for architectural effect.
U-tube heat exchanger: A heat-exchanger system consisting of a bundle of U tubes (hairpin tubes) surrounded by a shell (outer vessel), one fluid flows through the tubes, and the other fluid flows through the shell, around the tubes.
U-tube manometer: A manometer consisting of a U-shaped glass tube partly filled with a liquid of known specific gravity, when the legs of the manometer are connected to separate sources of pressure, the liquid rises in one leg and drops in the other, the difference between
U-value: A measure of heat transmission through a building part or a given thickness of insulating material, expressed as the number of British thermal units that will flow in 1 hour through 1 square foot of the structure or material from air to air with a tempera
Underwood chart: A graphical solution of mass balances for a single equilibrium stage in the calculation of a solvent-extraction operation.
Underwood distillation method: A method for calculation of liquid separations from binary distillation systems operated at partial reflux.
United States standard dry seal thread: A modified pipe thread used for pressure-tight connections that are to be assembled without lubricant or sealer in refrigeration pipes, automotive and aircraft fuel-line fittings, and gas and chemical shells.
Unsin engine: A type of rotary engine in which the trochoidal rotors of eccentric-rotor engines are replaced with two circular rotors, one of which has a single gear tooth upon which gas pressure acts, and the second rotor has a slot which accepts the gear tooth.