Patent GB-824365-A (GB)
Title: Improvements in pulsation dampening or surge absorbing apparatus
IPC: F16L55/054
Filed: 1956-11-23
Abstract: 824,365. Pressure-relieving devices for fluids. WESTINGHOUSE AIR BRAKE CO. Nov. 23, 1956 [Nov. 25, 1955 (2); Dec. 29, 1955; Jan. 30, 1956; Jan. 31, 1956 ; Feb. 27, 1956; March 27, 1956], No. 35844/56. Class 135. A pulsation dampening or surge absorbing apparatus for installation in a conduit conducting fluid comprises a hollow mandrel having a plurality of throttling orifices in its wall and surrounded by an elastic sleeve defining a space between itself and the mandrel, the mandrel or the sleeve being provided with spaced projections disposed within said space and affording a support for the sections of the sleeve intermediate the projections and resilient means being provided externally of the sleeve to restrain radial distention thereof. The cylindrical mandrel 11, Fig. 1, is fitted by screwthreaded ends 6, 7 to a pipe line carrying fluid under pressure. The mandrel 11 has longitudinal rows of orifices 25, 26, 27, 28 and longitudinal lobes 21, 22, 23, 24, Fig. 2. Surrounding the mandrel and abutting the lobes is an elastic sleeve 18 and spaced from the sleeve is a cylindrical casing 10. The outer flanges 19, 20 of the sleeve 18 are clamped between end plates 12, 13 and flanges 47, 48 of the casing 10. A valve 37 may be operated to introduce compressed air into the space 31 and a gauge 34 indicates the pressure of such air which pressure is selected in accordance with the expected value of the pulsations in the pipe line to which the apparatus is attached. The pulsating fluid flows out through the orifices 25, 26, 27, 28 to radially expand the sleeve 18 and during the pressure reduction which follows a surge the air pressure on the sleeve 18 forces it inwardly against the surface of the mandrel. In a second example, Figs. 3 and 4, the mandrel 11 has three longitudinal lobes and is located by pins 66, 67 between the end plates 12, 13 which have threaded bores 70, 71. The compressed air is introduced by the bore 64 to force the sleeve away from the casing wall, grooves 77 being provided to facilitate this movement. The bolts 76 hold the assembly together. In another example, Fig. 5, the lobes are formed by rods 80 of semi-circular cross-section spot-welded to the mandrel 11. The orifices 84 in the mandrel open into annular grooves 85. The casing 10 is formed by a central section 86 and two end sections 87, 88 welded thereto. Cupshaped members 82, 83 which locate the rods 80 are held in the flanges 12, 13. In another similar example, Fig. 9, the rods 93 are of arcuate cross-section and they are aligned with the orifices 84 and are provided with slots 94. In another example, Fig. 12, the mandrel 11 is tubular and the sleeve 18 has inwardly projecting ribs 140, 141, 142, 143 which abut the mandrel between the orifices 112, 113, 114, 115. The tops of the ribs may be curved or, as shown, flat. The sleeve 18 may be longitudinally corrugated, Fig. 19. In another example, Fig. 14, the sleeve 18 is annularly corrugated, the inner ribs resting on the mandrel 11. The sleeve may comprise two separate sleeves, Fig. 17, the inner one of a material having a high resistance to chemical action by the fluid and the outer one of a material having a high elasticity and strength. A lubricant, e.g. graphite, or a reinforcing sleeve, e.g. of nylon, may be interposed between the two sleeves.