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Correct Installation of Common Flowmeters

A flow meter is an instrument that indicates the measured flow rate and/or the total amount of fluid in a selected time interval. It is also an indispensable instrument for measuring liquid and gas flow. Everyone must have seen many different types of flow meters. The correct installation method is very important for the flowmeter. Let's follow this article to learn about the installation points of several commonly used flowmeters.

Ⅰ. Electromagnetic flowmeter

The measurement principle of the electromagnetic flowmeter does not depend on the characteristics of the flow. If there is a certain turbulent flow and vortex in the pipeline, it has nothing to do with the measurement.

Installation points:

1. There should be no large vibration source at the installation site, and reinforcement measures should be taken to stabilize the pipeline near the instrument;

2. It cannot be installed near equipment that generates large magnetic fields such as large transformers, motors, pumps, etc., so as to avoid interference from electromagnetic fields;

3. When the sensor is connected to the pipeline, it should be ensured that the pipeline is full, and it is best to install it vertically;

4. The transmitter shell is grounded and connected to the nearest grounding network; the shielded cable (split type) is connected according to the instructions, and the signal cable (to the system) is grounded at one end at the shielding layer system; the short-circuit ring connecting the measuring sensor and the pipeline needs to be grounded, the grounding resistance should be less than 10 ohms and cannot be shared with electrical grounding;

5. There should also be a certain straight pipe section upstream of the flowmeter sensor, generally 5D~10D.

Ⅱ. Ultrasonic flowmeter

Ultrasonic flowmeter is also a relatively common flowmeter. Its installation is the most simple and convenient in the installation of all flowmeters. Just select a suitable measurement point, input the pipeline parameters at the measurement point into the flowmeter, and then put the probe Just fix it on the pipe.

Installation points:

1. Choose a pipe section filled with fluid that is uniform and dense and easy to transmit ultrasonic waves, such as vertical pipe section or horizontal pipe section.

2. The installation distance should be selected as a straight pipe section with no valves, elbows, variable diameters, etc. within the upstream diameter greater than 10 times the straight pipe diameter and downstream greater than 5 times the straight pipe diameter. The installation point should be sufficiently far away from valves, pumps, high-voltage electricity and Inverter and other interference sources.

3. Avoid installing on the highest point of the piping system or vertical pipes with free exits.

4. For open or half-filled pipes, the flowmeter should be installed at the U-shaped pipe section.

Ⅲ. Vortex flowmeter

The main installation requirements of the vortex flowmeter are the requirements for straight pipe sections and pipeline vibration requirements. There should be long straight pipe sections on the upstream and downstream sides of the vortex flowmeter; the pipeline must not have vibration. If there is vibration, the flowmeter needs to be adjusted. Add fixings on both sides.

Installation points:

For the vortex flowmeter, when measuring the gas flow, if the measured gas contains a small amount of liquid, the flowmeter should be installed at a higher part of the pipeline.

When measuring liquid, if the measured liquid contains a small amount of gas, the flowmeter should be installed at the lower part of the pipeline.

1. Pressure measuring hole and temperature measuring hole: When pressure measurement is required, the pressure measuring hole must be set at 2~7D downstream of the flowmeter. When temperature measurement is required, set the temperature sensor between 1 and 2D downstream of the pressure measurement point.

2. Pipe support: try to install the flowmeter in a place where the vibration acceleration is less than 20m/s 2 . When the vibration of the pipeline is too strong, the reinforcement support should be installed on the pipeline.

3. Gasket: The gasket must not protrude into the pipeline, otherwise it will cause unacceptable errors.