Precautions for turbine flowmeter

1. Function check

The accuracy level and function of the instrument are selected based on measurement requirements and usage scenarios to achieve cost-effectiveness. For example, in situations such as trade settlement, product handover, and energy measurement, higher accuracy levels such as 1.0, 0.5, or higher should be selected; For process control applications, choose different accuracy levels according to control requirements; In some cases where only the process flow is detected without the need for control and measurement, a slightly lower accuracy level, such as 1.5, 2.5, or even 4.0, can be selected. In this case, a low-cost plug-in turbine flowmeter can be used.

2. Measurable medium

When measuring medium flow rate, instrument range, and caliber for general medium measurement, the full flow rate of the turbine flowmeter can be selected within the range of 0.5-12m/s for measuring medium flow rate, which is relatively wide. The selection of instrument specifications (caliber) may not necessarily be the same as the process pipeline, and should be determined based on whether the measured flow range is within the flow rate range. That is, when the pipeline flow rate is too low to meet the requirements of the flow instrument or the measurement accuracy cannot be guaranteed at this flow rate, the instrument port diameter needs to be reduced to manage the internal flow rate and obtain satisfactory measurement results.

install

To ensure accurate measurement of the turbine flowmeter, the correct installation location and method should be selected

Requirements for straight pipe section: The flowmeter should be installed horizontally on the pipeline (with a pipeline inclination within 5 degrees), and the axis of the flowmeter should be concentric with the axis of the pipeline during installation, with the flow direction consistent. The upstream pipeline length of the flowmeter should have an equal diameter straight pipe section of not less than 2D. If the installation site permits, it is recommended that the upstream straight pipe section be 20D and the downstream be 5D.

Requirements for piping: The inner diameter of the upstream and downstream piping at the flowmeter installation point should be the same as the inner diameter of the flowmeter.

Requirements for bypass pipe: In order to ensure that the maintenance of the flowmeter does not affect the normal use of the medium, shut-off valves (globe valves) should be installed on the front and rear pipelines of the flowmeter, and a bypass pipe should also be installed. The flow control valve should be installed downstream of the flow meter. When using the flow meter, the upstream shut-off valve should be fully opened to avoid unstable flow of fluid in the upstream section.

Requirements for external environment: When installing the flow meter indoors or outdoors, it must be protected from rain Lightning protection measures should be taken to avoid affecting the service life.

Requirement for impurities in the medium: In order to ensure the service life of the flowmeter, a filter should be installed before the straight pipe section of the flowmeter.

Installation location: The flowmeter should be installed in a location that is easy to maintain, free from strong electromagnetic interference and thermal radiation

Requirement for installation: The user shall provide another pair of standard flanges welded onto the front and rear pipelines. No flow meter allowed! Before installing the flowmeter, welding slag and other dirt in the pipeline should be strictly inspected, and an equal diameter pipeline (or bypass pipe) should be used instead of the flowmeter to blow the pipeline. To ensure that the flow meter is not damaged during use. When installing a flowmeter, the sealing gasket between the flanges should not be recessed into the pipeline.

Requirements for flowmeter grounding: The flowmeter should be reliably grounded and cannot be shared with the grounding wire of the high-voltage system.

Requirements for explosion-proof products: In order to ensure the normal use of the instrument, it is necessary to review whether the usage environment of the explosion-proof flowmeter complies with the user's explosion-proof requirements. During installation and use, strict adherence to the national requirements for the use of explosion-proof products is required. Users are not allowed to change the connection method of the explosion-proof system or open the instrument at will. Select within the specified flow range to prevent operation and ensure ideal accuracy and normal service life. Before installing the flowmeter, the pipeline should be cleaned of debris such as fragments, welding slag, stones, dust, etc. It is recommended to install a 5-micron sieve filter upstream to block liquid droplets and sand particles. When the flowmeter is put into operation, the front valve should be slowly opened first, and then the rear valve should be opened to prevent instantaneous airflow impact and damage to the turbine. Lubricating oil should be added according to the signs, and the frequency of refueling depends on the cleanliness of the gas, usually 2-3 times a year. Due to pressure testing, pipeline purging, or exhaust causing turbine operation, as well as turbine operation in reverse flow, the flow meter may be damaged. It is not allowed to open the flowmeter randomly before operation Rear cover, modify internal parameters, otherwise it will affect the normal operation of the flowmeter. Be careful when installing the gasket to ensure that no protrusions enter the pipeline to prevent interference with normal flow measurement. When calibrating a flowmeter, pressure should be collected at the pressure tap of the flowmeter.