NOISE REDUCING DEVICE OF DRAIN PIPING

摘要

PROBLEM TO BE SOLVED: To suppress a vibration generated to the peripheral wall by the action of an inner flowing water, to reduce a noise resulting from the vibration effectively, and at the same time, to prevent to expedite the expansion of the fire in the using condition of a noise reducing device, by installing the noise reducing device at an adequate position of a drain piping. SOLUTION: At the outer side of the peripheral wall of the diameter contraction pipe 11 of a drain collecting pipe which forms a part of a drain piping, a weighted body 20 made of a viscoelastic metal; an elastic body 21 made of an elastic material at the outer side; and an outer package body 22 at the outer side of them; are wound, and the vibration of the diameter contraction pipe 11 is suppressed by adding the weight by the weighted body 20, and the viscoelastic property of the weighted body 20 and the elasticity of the elastic body 21 under the constraint from the outer side by the outer package body 22. The outer package body 22 is made of a non-combustible material, collar edges 25 and 25 extruding inward are formed at the end edge of the outer package body 22, and the collar edges 25 cover the outer side of the elastic body 21 being a combustible material, including both ends in the axial direction, so as to suppress the ignition to the elastic body 21 in a fire generating case, or to reduce the degree of the combustion of the elastic body 21.