GB946408A - Improvements in or relating to flanged joints to vessels and conduits - Google Patents

Abstract

946,408. Screwing up and unscrewing nuts. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Oct. 10, 1961 [Oct. 22, 1960], No. 36319/60. Heading B3N. [Also in Division F2] A flanged joint has an inner gasket seal and an outer annular seal, a number of fastening devices for loading the inner seal pitched on a circle between the seals, a sealed containment enclosing each of the fastening devices and means for applying an operating torque to the fastening devices from outside the containments thereof. As shown, the mutually facing surfaces 1a, 2a of flanges 1, 2 are formed with seal faces 4, 5 to form a continuous, annular seal, and these surfaces are stepped at 6 to define an annular space 7. The flanges have peripheral extensions 8 engaged by a flexible, metal O- section ring 9 which in conjunction with seal welds 9a form the outer seal. Each screwthreaded stud 10 is, at one end, permanently engaged in a hole 12 in the flange 1, and, at the the other end thereof, engaged in a nut 10b; a blind axial bore 12a in the stud accommodates a heating sleeve 12b which may incorporate an electric heating element and a pneumatic indicating extensometer. A sleeve 13 forming a sealed containment for the stud is screwed in the flange 2a and has a hemispherical termination 14a carrying the spigot 21a of a cap 21 to which is attached a spring 20 supporting through a thrust bearing 19 a stationary cap 18 bearing on the nut 10b the spigot is secured in a journal bearing in a plate 23 closing the end of a driven ring gear tube 24 provided with gear teeth 24a and rotatable in the bearing 22 and on a needle roller bearing 25 carried by an extension 14 of the sleeve 13. A thermal stress reducing sleeve 15 and one end of a torque tube 17 is secured by a pin 16 to the sleeve 13, the tube 17 having on the inner face thereof teeth of V-shape profile which engage with correspondingly shaped teeth on the nut 10b. The inner race of the bearing 25 is circular and concentric with the extension 14 while the outer race is elliptical such that on rotation of the ring gear 24 the extension 14 and tube 17 are radially deformed at successively different contiguous parts of the peripheries thereof in a manner that a number of V-shaped teeth on the tube 17 engage the adjacent teeth of the nut 10b to effect rotation of the nut. Drive of the ring gear tube is obtained from an air motor through a compound epicyclic torque amplifier which comprises an annulus 27 having compound gears 27a, 27b and a sun wheel 28 acting as a motor stator. The motor 26 has a rotor 29 with vanes 29a in a chamber to which compressed air is supplied from one or other of pipes 30 and tubular bearing portions 31 extend from the rotor, the inner and outer surfaces 31a, 31b respectively of those portions being concentric with the axis of the rotor and engaging concentric bearings 32, 33 carried by the stator 28 and eccentric to the rotor and carrying eccentric bearings 34, 35 for the compound annulus 27. The latter is formed with longitudinal slots to provide a degree of torsional flexibility, and the output teeth 27a thereof are in engagement with the teeth 24a of the ring gear 24. In making the joint, the detachable flange 2 carrying the drive motor and nut 10b and sealing ring 9 is lowered on to the flange 1 so that the studs 10 enter the bores of the nuts 10b and strike the screw-threaded parts of the nuts, further movement of the flange causing the nuts to compress the springs 20 until the seal faces 4, 5 engage one another. The motor causes rotation of the ring gear tube 24 and thereby rotation of the nut 10b which travels along the stud to engage the thermal sleeve 15. To tighten the nuts further, the electrical heating elements in the sleeves 12b are switched on for alternate studs and after a predetermined degree of thermal expansion, the motors are again applied to tighten the nuts. The remaining studs are then similarly heated and the nuts thereof tightened by the appropriate motors. Specifications 790,171 and 946,409 are referred to.