10 Product Specifications
10-2. Principle of this product
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10-2-4. Principle of sonic sensor
A schematic diagram of the sonic sensor is shown above. This sensor emits a sound from the sound
source into a tube in which a measuring gas flows and then measures the time
τ
in which the sound
travels through the measuring gas and arrives at the sound receiver.
The speed of sound that travels through the measuring gas
v
GAS
can be expressed as the following
formula:
L
v
GAS
L
: Distance from the sound wave source to the sound receiver
τ
: Time in which a sound from the sound source arrives at the sound receiver
The distance from the sound source to the sound receiver
L
is physically quite stable. Therefore, the speed
at which a sound travels through the measuring gas
v
GAS
can be accurately obtained by measuring the
sound travel time
τ
.
Sound
receiver
Sound source
Measuring gas inlet
Measuring gas outlet
