Inline ultrasonic attenuator with helical baffle

A method for attenuating ultrasonic waves downstream of a ultrasonic gas flow meter, the method comprising:

• providing an in-line ultrasonic attenuator that includes:
• a longitudinally extending pipe having a first end, a second end, and a constant inside diameter extending an entire distance between the first and second ends;
• a first and a second helical baffle housed between the first and second ends and arranged in series with one another coaxial to the longitudinally extending pipe;
• the first helical baffle having first twist rotation and the second helical baffle having a second twist rotation opposite that of the first twist rotation, each twist rotation being at least 180°.

An in-line ultrasonic attenuator comprising:

• a longitudinally extending pipe having a first end, a second end, and a constant inside diameter extending an entire distance between the first and second ends;
• a first and a second helical baffle housed between the first and second ends and arranged in series with one another coaxial to the longitudinally extending pipe;
• the first helical baffle having first twist rotation and the second helical baffle having a second twist rotation opposite that of the first twist rotation, each twist rotation being at least 180°;
• each of the first and second helical baffles including a plurality of bars, each bar of the plurality having a length equal to that of the constant inside diameter of the longitudinally extending pipe and being oriented at a different angular orientation than a corresponding adjacent bar of the plurality.

An in-line ultrasonic attenuator comprising:

• a longitudinally extending pipe having a first end, a second end, and a constant inside diameter extending an entire distance between the first and second ends;
• a first and a second helical baffle housed between the first and second ends and arranged in series with one another coaxial to the longitudinally extending pipe;
• the first helical baffle having first twist rotation and the second helical baffle having a second twist rotation opposite that of the first twist rotation, each twist rotation being at least 180°;
• wherein the first and second helical baffles reduce a cross-section of the constant inside diameter by no more than 5%.