Patent ID: 9671261
Date: 2017-06-06
CPC Classifications: G01F

Claim:
1. An ultrasonic flowmeter comprising: a first ultrasonic transceiver provided on a first part of an outer periphery on an upstream side of a conduit in which gas flows; a second ultrasonic transceiver provided on a second part of the outer periphery on a downstream side of the conduit; a main unit measuring a flow quantity of the gas based on a downstream time from when a downstream ultrasonic wave transmitted from the first ultrasonic transceiver to when the downstream ultrasonic wave is received by the second ultrasonic transceiver and an upstream time from when an upstream ultrasonic wave transmitted from the second ultrasonic transceiver to when the upstream ultrasonic wave is received by the first ultrasonic transceiver; and an ultrasonic absorber provided on the outer periphery of the conduit, the ultrasonic absorber absorbing the upstream and downstream ultrasonic waves propagating in the conduit, wherein the ultrasonic absorber comprises a first uncrosslinked rubber layer formed on the outer periphery of the conduit and a second rubber layer formed on the first uncrosslinked rubber layer, and the first uncrosslinked rubber layer has a viscoelasticity larger than the second rubber layer and the second rubber layer has a viscoelasticity smaller than the first uncrosslinked rubber layer and surrounds the first uncrosslinked rubber layer.