1、 Overview

Turbine flowmeter (hereinafter referred to as TUF) is the main type of impeller flowmeter, which also includes anemometer, water meter, etc. TUF consists of sensors and conversion displays. The sensors use a multi blade rotor to sense the average flow velocity of the fluid, thereby deriving the flow rate or total amount. The rotation (or number of revolutions) of the rotor can be detected by mechanical, magnetic induction, and photoelectric methods, and displayed and recorded by a reading device. It is said that the United States issued its first TUF patent as early as 1886, and the 1914 patent believed that the traffic of TUF was related to frequency. The first TUF in the United States was developed in 1938 for measuring the flow of fuel on airplanes. However, it was not until after World War II that a high-precision, fast response flow meter was urgently needed for liquid jet fuel in jet engines, which allowed it to achieve true industrial applications. Nowadays, it has been widely used in various departments such as petroleum, chemical, scientific research, national defense, and metrology.

2、 Product Features

1. High precision, generally up to ± 1% R, ± 0.5% R, and high-precision models up to ± 0.2% R;

2. Good repeatability, short-term repeatability can reach 0.05%~0.2%. It is precisely because of its good repeatability that frequent calibration or online calibration can achieve extremely high accuracy, making it a preferred flowmeter in trade settlement;

3. On site display, instantaneous flow and cumulative flow

4. Output pulse frequency signal, 4-20mA, 485 communication

5. Can obtain high frequency signals with strong signal resolution;

6. Wide range, with a medium to large caliber of up to 1:20 and a small caliber of 1:10;

7. Compact and lightweight structure, easy installation and maintenance, and high circulation capacity;

8. Suitable for high voltage measurement, there is no need to open holes on the instrument body, making it easy to make high voltage instruments;

9. There are various types of specialized sensors that can be designed according to the specific needs of users, such as low-temperature, bidirectional, downhole, sand mixing, etc;

10. Can be made into an insertion type, suitable for measuring large diameters, with low pressure loss, low price, can be removed without interruption, and easy installation and maintenance;

3、 Technical specifications

Technical Parameter

Caliber Flow Comparison Table

4、 Outline dimensions and installation diagram

Typical installation pipeline system diagram of turbine flowmeter (see Figure 1)

Precautions for pipeline installation

The sensor should be installed in a location that is easy to maintain, with no vibration, strong electromagnetic interference, or thermal radiation in the pipeline.

Horizontal installation of sensors requires that the pipeline should not have any visible tilt (generally within 5 °), and vertical installation of sensors should also have a verticality deviation of less than 5 °. In places where the flow cannot be stopped, a bypass pipe and a reliable shut-off valve (see Figure 1) should be installed, and the measurement should ensure that the bypass pipe is leak free.

At the location where the sensor is installed in the newly laid pipeline, a short pipe is first connected to replace the sensor. After the "line sweeping" work is completed and the pipeline is confirmed to be clean, the sensor can be officially connected.

If the fluid contains impurities, a filter should be installed on the upstream side of the sensor, and the pipeline should be regularly cleaned to discharge sediment impurities; If the measured liquid contains gas, a gas eliminator should be installed on the upstream side of the sensor. The discharge and exhaust ports of filters and air purifiers should be connected to a safe location.

If the sensor is installed at the low point of the pipeline, to prevent impurities from settling and accumulating in the fluid, a discharge valve should be installed in the subsequent pipeline to regularly discharge the settled impurities.

When installing sensors outdoors, measures should be taken to avoid direct sunlight and rain.

Requirements for installing straight pipe sections

The length of the straight pipe section of the turbine flowmeter is sensitive to the distortion of flow velocity distribution and rotational flow in the pipeline. When entering the sensor, turbulence should be fully developed. Therefore, necessary straight pipe sections or rectifiers should be equipped according to the type of upstream flow resistance of the sensor, and the length of the straight pipe sections at the inlet and outlet should be required.

If the situation of the upstream blocking component is unclear, it is generally recommended that the length of the upstream straight pipe section be no less than 20D and the length of the downstream straight pipe section be no less than 5D. If the installation space cannot meet the above requirements, a flow regulator can be installed between the blocking component and the sensor. When installing sensors outdoors, measures should be taken to avoid direct sunlight and rain.

Function:

）Frequency measurement with accuracy ranging from 0.8 to 3KHz;

2) 4-20mA output;

3) Upper and lower limit alarm output, the monitored parameters, high and low alarms, and level output methods can be set as needed; 4) Three 12 bit AD inputs (temperature, pressure, battery voltage);

5) 0-1000Hz frequency output;

6) Accumulated traffic can be recorded.

7) The average power consumption of the whole machine is 450 μ A.

5、 Wiring diagram:

1) Jumper version

2) Dial up version

3) The meaning of terminal blocks is as follows:

4) Jumper (DIP) diagram

5) Wiring diagram

6、 Precautions for use

On site installation and maintenance must comply with the warning message "Do not open the lid when there is explosive gas", and turn off the external power before opening the lid.

When conducting a sealing pressure test after pipeline installation, attention should be paid to the maximum pressure that the flow meter pressure sensor can withstand to avoid damaging the pressure sensor.

When put into operation, the upstream and downstream valves of the flowmeter should be slowly opened to avoid damage to the instrument and pipeline caused by sudden rapid airflow.

When the flowmeter requires signal remote transmission, it should be strictly connected to an external power supply of 24VDC according to the requirements of Section 3.4 "Electrical Performance Indicators". It is strictly prohibited to directly connect a 220VAC or 380VAC power supply at the signal input port.

5. Users are not allowed to change the wiring method of the explosion-proof system or arbitrarily twist various output lead connectors;

When the flowmeter is running, it is not allowed to open the front cover to change the instrument parameters, otherwise it will affect the normal operation of the flowmeter;

7. Do not loosen the fixed part of the flowmeter at will.

When using the product outdoors, it is recommended to add a waterproof cover.

9. The opening and closing sequence of the operation

For flow sensors without bypass pipes, first open the upstream valve of the flow sensor with a medium opening, and then slowly open it

Open the downstream valve. Run at a low flow rate for a period of time (such as 10 minutes), then fully open the upstream valve, and then increase the downstream valve opening to adjust to the required normal flow rate.

For a flow sensor equipped with a bypass pipe, first fully open the bypass pipe valve, open the upstream valve at a moderate opening, slowly open the downstream valve, and reduce the opening of the bypass valve to allow the instrument to operate at a lower flow rate for a period of time. Then fully open the upstream valve, fully close the bypass valve (to ensure no leakage), and finally adjust the downstream opening to the required flow.

10. Activation of low and high temperature fluids

The low-temperature fluid pipeline is cleaned of moisture in the pipeline before passing through. When passing through, it runs at a very low flow rate for 15 minutes before gradually increasing to normal flow rate. When stopping the flow, it should also be done slowly to gradually approach the pipeline temperature and ambient temperature. High temperature fluid operation is similar to this.

11. The opening and closing valve should be as smooth as possible. If automatic control is used for opening and closing, it is best to use the "two-stage opening, two-stage closing" method to prevent sudden fluid impact on the impeller or even water hammer damage to the impeller.

12. Check the downstream pressure of the flow sensor. When the pipeline pressure is not high, observe whether the downstream pressure of the sensor at the maximum flow rate is greater than Pmin calculated by formula 5 during the initial operation. Otherwise, measures should be taken to prevent cavitation.

The instrument coefficient of the flow sensor is calibrated by a standard device and specified on the calibration sheet provided to the user to prevent loss.

Long term use of sensors may cause changes in instrument coefficients due to bearing wear and other reasons, and should be regularly calibrated offline or online. If the flow exceeds the allowable range, the sensor should be replaced.

13. For some measuring objects, such as oil pipeline replacement or shutdown, regular line cleaning and cleaning work is required. Make it. The flow direction, flow rate, pressure, and temperature of the fluid used for pipeline cleaning should comply with the requirements of the turbine flowmeter, otherwise it may cause a decrease in accuracy or even damage.

To ensure the long-term normal operation of the flowmeter, it is necessary to strengthen the operation inspection of the instrument, and take timely measures to eliminate any abnormalities once discovered. Monitor the rotation of the impeller. If any abnormal sound is heard, use an oscilloscope to monitor the output waveform of the detection coil. If there is any abnormal waveform, remove and inspect the internal components of the sensor in a timely manner. If there is suspicion of any abnormal phenomenon, it should be checked in a timely manner. Keep the filter unobstructed, and the filter can be judged for blockage based on the pressure difference between the inlet and outlet pressure gauges. Regularly discharge the gas escaping from the liquid in the gas purifier, etc.

7、 Common faults and their solutions

8、 Selection