Download MULTICAL® 302 - Technical Description

MULTICAL® 302 In principle, the flow is determined by measuring the flow velocity and multiplying it by the area of the measuring pipe:
Q FA
where:
Q is the flow
F is the flow velocity
A Is the area of the measuring pipe
The area and the length, which the signal travels in the sensor, are well-known factors. The length which the signal
travels can be expressed by L  T  V , which can also be written as:
T
L
V
where:
L is the measuring distance
V is the sound propagation velocity
T is the time
1 1
T  L    
 V1 V2 
In connection with ultrasonic flow sensors the velocities
V1  C  F
and V2
CF
V1 and V2 can be stated as:
respectively
where: C is the velocity of sound in water
Using the above formula you get:
T  L 
1
1

CF CF
which can also be written as:
T  L 
(C  F )  (C  F )
(C  F )  (C  F )

T  L 
As
CF - F 2
F
56 2F
C  F2
2
can be omitted and the formula reduced as follows:
T  C 2
L2
Kamstrup A/S ∙ Technical Description ∙ 5512‐1334_E1_GB_05.2015