Fuji ultrasonic flowmeter probe installation method and orientation. Generally, there are two probe installation methods: V method and Z method, and experience shows that the measurement accuracy of V method is higher than that of Z method without affecting the signal reception. Because the installation of the V-method probe facilitates accurate positioning, the measurement error is mainly due to the flow pattern and pipe parameters. The Z method installation sound range is short, although the signal is strong, the probe positioning is difficult, easy to produce installation errors, large diameter pipeline is more prominent.

Fuji Ultrasonic Flowmeter

Fuji Ultrasonic Flowmeter   FSC/FSV/FLR

The relationship between installation and measurement accuracy

1. Fuji flowmeter probe installation method and orientation. There are generally two probe installation methods: V method and Z method,

Experience has shown that without compromising signal reception,

The measurement accuracy of V method is higher than that of Z method. Because the V-method probe is easily installed for accurate positioning,

Therefore, the measurement error mainly comes from the flow pattern and pipeline parameters.

The Z method installation of short acoustic range, although the signal is strong, probe positioning is difficult, easy to produce installation errors,

Large diameter pipe is more prominent.

2. Probe spacing and radial misalignment.

The positioning error of probe spacing causes the error of sound path size, directly affects the measurement accuracy, and can not find the signal in serious cases.

Table 4 Relationship between probe spacing deviation and measurement accuracy of V-tube installation

The radial misalignment of the probe has little effect on the measurement results, but it will affect the signal strength. Installation requires the sound beam to pass through the center of the pipe,

Otherwise, the signal will be seriously attenuated due to the inconsistency between the acoustic wave transmission and the receiving Angle, until it can not be measured.

3. Installation environment, coupler, signal cable and more. Portable ultrasonic flowmeter with multi-pulse, wide-band signal,

With a certain ability to resist electromagnetic interference,

However, there are high frequencies in the installation site, especially when the frequency conversion interference source cannot work completely. Too long a probe signal cable will attenuate the signal,

Generally not more than 200 meters,

And should use a specific impedance of coaxial cable, special end, there can be no joint in the middle. Ultrasonic coupler as far as possible to use good acoustic conductivity,

Sticky substances that are not easy to mix with gas, such as water glass, petroleum jelly, etc.

The above brief analysis of the portable ultrasonic flowmeter due to pipeline and installation factors caused by the accuracy and use of some problems.

In fact, there are two main factors causing the error: first, the calculation error of the cross-sectional area of the pipeline,

This is a common problem with all flowmeters.

The second is the ultrasonic path error, according to the principle of the time difference flowmeter:

由：t1　= L / ( C + v )

t2　= L / ( C－v )

Δt = t2 － t1 = 2 L v / C2

得：v　= Δt C2 / 2 L，

Decrease, the measurement result is low, vice versa high.