Correct installation steps for clamp-on ultrasonic flowmeter

 

In the flow meter measurement in industrial production, in addition to the normal fixed pipeline type flow measurement device, there are often some flow measurement requirements that are not suitable for pipeline installation, or temporary and mobile. In this case, the external clamp ultrasonic flow meter can be useful, because the ultrasonic flow meter is a non-contact measuring instrument that can be used to measure the flow of fluids that are not easy to touch and observe and the flow of large pipe diameters. It does not change the flow state of the fluid, does not cause pressure loss, and is easy to install, so it is generally popular. However, the installation conditions of the ultrasonic flow meter are relatively strict, and the correctness of the installation method also has an important impact on the measurement of data.

Clamp-on ultrasonic flow meter

1. Before installing the ultrasonic flow meter, you should understand the site conditions, including:

1. How far is the installation site from the host;

2. Pipeline material, pipe wall thickness and pipe diameter;

3. Pipeline age;

4. Fluid type, whether it contains impurities, bubbles, and whether it is full;

5. Fluid temperature;

6. Whether there is an interference source (such as frequency conversion, strong magnetic field, etc.) at the installation site;

7. Temperature in all seasons where the host is placed;

8. Is the voltage used stable?

9. Is it necessary to transmit the signal remotely and what type?

Based on the above-mentioned on-site conditions, the manufacturer can configure the device according to the on-site conditions and can also make a special model if necessary.

2. The selection of the installation pipe section has a great influence on the test accuracy. The selected pipe section should avoid interference and eddy current, which have a great influence on the measurement accuracy. Generally, the selected pipe section should meet the following conditions:

1. Avoid installing the machine near water pumps, high-power radio stations, and frequency conversion, that is, where there are strong magnetic fields and vibration interference;

2. The pipe material should be uniform and dense, and the pipe section should be easy to transmit ultrasonic waves;

3. There should be a long enough straight pipe section. The upstream straight pipe section of the installation point must be greater than 10D (Note: D=diameter), and the downstream should be greater than 5D;

4. The upstream of the installation point should be 30D away from the water pump;

5. The fluid should fill the pipeline;

6. There should be enough space around the pipeline for on-site personnel to operate, and underground pipelines need to be tested.

Flow Sensor installation diagram

V method DN15mm-200mm pipelines are preferred to use V method. When installing, align the two sensors of the external clamp ultrasonic flowmeter horizontally, and their center lines are parallel to the pipeline axis. Note that the emission directions must be relative (the two sensors are facing inward). The V method is easy to use and accurate in measurement. For pipes with a diameter less than DN50mm, the installation accuracy is higher. Please pay attention to the parameters of signal strength, signal quality, and transmission time ratio.

Z method is preferred for pipes with DN200mm-6000mm. It can also be used when the V method cannot detect the signal or the signal quality is poor. When installing, make the vertical distance between the two sensors along the pipe axis equal to the installation distance, and ensure that the two sensors are on the same axis. Note that the transmitting directions must be relative (the two sensors are facing inward). Since the Z method is the direct transmission and reception of ultrasonic waves in the medium, there is no reflection of the signal, so the signal strength attenuation is minimal. Therefore, the Z method has the characteristics of high signal strength and reliable operation.

4. Enter the measurement parameters to obtain the installation distance

Before starting the measurement, the flow meter needs to be initially set up. Usually, the 10-26 menus are set up one by one (the M39 menu is available in multiple languages). After the setting is completed, the sensor installation distance can be obtained in M25. This distance refers to the innermost edge distance of the two sensors, and the sensor is installed according to this data.

5. Processing the installation point

There are two installation points for the clamp-on ultrasonic flow meter sensor, which are divided into upstream sensors and downstream sensors. When processing these two installation points, the processing area of ​​one installation point can be about the same as the probe size, and the processing area of ​​the other installation point should be 2 or 3 times the size of the probe (centered on the installation point) to facilitate signal debugging. First, clean the area outside the pipe where the sensor is to be installed, and remove rust and paint. If there is an anti-rust layer, it should also be removed. It is best to use a grinder to grind out the metallic luster, and then wipe off the oil and dust with a clean rag.