Turbine flow meter selection, installation, use matters needing attention

Turbine flowmeter is a new type of smart meter integrated with integrated display and calculation using advanced ultra-low-power single-chip microcomputer technology. It adopts double-row liquid crystal field display, compact structure, clear and intuitive reading, high reliability, No obvious interference from external power supply, lightning strike, low cost and other obvious advantages.

Selection

Turbine flowmeters are properly sized to ensure better use of turbine flowmeters. What type of turbine flow meter should be used depends on the physical properties and chemical properties of the fluid medium to be measured, so that the diameter, flow rate range, lining material, electrode material, and output current of the turbine flow meter can be adapted to the measured fluid. Nature and flow measurement requirements.

1, precision function check

Accuracy grades and functions Select the instrument accuracy grade according to the measurement requirements and the use occasions, so that it is cost-effective. For applications such as trade settlement, product handover, and energy metering, higher accuracy levels, such as 1.0, 0.5, or higher, should be selected. For process control applications, different accuracy levels are selected based on control requirements; some Is to detect the process flow, without the need for precise control and measurement occasions, you can choose a slightly lower accuracy level, such as 1.5, 2.5, or even 4.0, then you can use low-cost plug-in turbine flowmeter.

2. Measurable medium

When measuring medium flow rate, instrument range, and bore diameter to measure common media, the full flow rate of the turbine flow meter can be selected within the range of 0.5 to 12 m/s for measuring the media flow rate, and the range is wide. The selected instrument specification (diameter) is not necessarily the same as the process piping. The measurement flow range should be determined within the flow rate range. That is, when the flow rate of the pipeline is too low to meet the requirements of the flow meter or the measurement accuracy at this flow rate is not guaranteed, It is necessary to reduce the diameter of the instrument to increase the flow rate in the tube and obtain satisfactory measurement results.

installation

In order to ensure accurate measurement of the turbine flow meter, the installation location and method must be correctly selected

Requirements for the straight section: The flow meter must be installed horizontally on the pipeline (the pipeline is inclined within 5 degrees). When installing, the axis of the flow meter should be concentric with the axis of the pipeline and the flow direction should be consistent. The length of the pipeline upstream of the flowmeter shall 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 is 20D and the downstream is 5D.

Requirements for the piping: The inner diameter of the upstream and downstream piping of the flow meter installation point is the same as the inner diameter of the flow meter.

The requirements for the bypass pipe: In order to ensure that the meter does not affect the normal use of the media during inspection and repair, a cut-off valve (stop valve) should be installed on the front and back pipes of the flowmeter, and a bypass pipe should be provided. The flow control valve should be installed downstream of the flowmeter. When the flowmeter is used, the shutoff valve installed in the upstream must be fully opened to avoid unstable fluid flow in the upstream part.

Requirements for the external environment: The flowmeter is best installed indoors, must be installed outdoors, must use sun protection, rain, lightning protection measures, so as not to affect the service life.

Requirements for impurities in the media: To ensure the lifetime of the flowmeter, a filter should be installed in front of the straight section of the flowmeter.

Installation site: The flow meter should be installed in a place convenient for maintenance without strong electromagnetic interference and heat radiation.

Requirements for installation and welding: The user is equipped with a pair of standard flanges welded to the front and rear pipes. No flowmeter welding allowed! Before installing the flowmeter, it is necessary to strictly remove dirt such as welding slag from the pipeline, and it is best to use a pipe (or bypass pipe) of equal diameter instead of the flowmeter to purge the pipeline. To ensure that the flowmeter is not damaged during use. When installing the flowmeter, the gasket between the flanges cannot be recessed into the pipeline.

Flowmeter grounding requirements: the flowmeter should be reliably grounded and cannot be shared with the strong electrical system ground.

Requirements for explosion-proof products: For the safe and normal use of the instrument, it should be checked whether the use environment of the explosion-proof flowmeter is in conformity with the requirements of the user's explosion-proof requirements. During installation and use, the requirements of the national explosion-proof products must be strictly observed, and the user is not allowed to change it. The connection of the explosion protection system must not be opened at will. The selection is within the specified flow range to prevent overspeed operation to ensure the desired accuracy and ensure normal service life. Before installing the flowmeter, clean the inside of the pipeline: debris, welding slag, stones, dust, etc. It is recommended to install a filter with a 5 μm mesh upstream to block droplets and sand. 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 the instantaneous airflow impact from damaging the turbine. Lubrication should be operated according to the signboard. The number of refueling depends on the degree of cleanliness of the gas, usually 2-3 times per year. The flowmeter may be damaged due to overpressure of the turbine due to pressure test, purge piping or exhaust, and operation of the turbine in reverse flow. When the flowmeter is running, it is not allowed to open the front and back cover at random, and change the internal parameters, otherwise it will affect the normal operation of the flowmeter. Carefully install gaskets to ensure that no protrusions enter the piping to prevent interference with normal flow measurements. The flowmeter collects pressure on the flowmeter pressure port at the time of calibration.

use

Turbine flow meter should pay attention to what aspects:

1 Use of each road

1.1 After the installation is in place, make sure that all chips and debris have been removed, the system has been purged, pressure tested, air flow entered, and boosted to the flow meter inlet valve.

1.2 Open Turbine Flowmeter Upstream Bypass Ball Valve

1.3 Slowly open the small bypass valve upstream of the ZR-LWGY Turbine Flow Meter and slowly fill the gas until the turbine flowmeter is in front of the electrically forced seal ball valve.

Note: Turbo-flow meters can be damaged by high pressure or rapid pressure surges. In order to protect the gas turbine flow meter, the pressure increase applied to the turbine flow meter must not exceed 35 kPa/s. If the pressure change cannot be measured at the site, the monitoring turbine flow rate cannot be exceeded.

1.4 Close the bypass ball valve and stop valve.

1.5 Turn the handwheel to open the inlet force seal valve.

1.6 Slowly open the turbine meter downstream of the electric forced seal ball valve (at least for 1 minute), preferably using a manual switch on the electric actuator. Be careful not to overspeed the turbine meter.

1.7 According to steps 1.2-1.6, the entire system is fully charged and natural gas is measured.

2 Online Comparison of Gas Turbine Flow Meters (Comparison of Work and Main Roads)

2.1 Ensure that the inlet and outlet valves of the main road are closed.

2.2 In accordance with steps 1.2, 1.3, and 1.4 in “1 Use of Each Road,” pressurize the main road.

2.3 Close the work road outlet electric forced seal ball valve, slowly open the forced seal ball valve of the comparison pipe, slowly open the main road outlet electric forced seal ball valve (preferably to do three tasks at the same time).

2.4 The gas passes through the work path and the main path in turn. The two turbine meters can be compared to each other to check for large deviations.

2.5 When the comparison is finished, close the two forced seal ball valves on the alignment pipe and on the main road, and open the outlet ball valve of the working pipe (preferably, do three jobs at the same time).

2.6 At this time, the work route is back to work.

3 On-line calibration of gas ZR-LWGY turbine flowmeters using mobile calibration vehicles

3.1 Ensure that the electric forced seal ball valve between the two calibration ports is closed.

3.2 Open the ball valve on the blind plate of the calibration flange to ensure that there is no pressure inside the flange blind plate. Then remove the blind flange.

3.3 Connect the mobile calibration car and calibration port.

3.4 In accordance with steps 1.2, 1.3, and 1.4 in “1 Use of Each Road,” pressurize the main road.

3.5 Close the work road outlet electric forced seal ball valve, slowly open the forced seal ball valve of the comparison pipe, and slowly open the two calibrated forced seal ball valves on the main road (preferably, do the four tasks at the same time).

3.6 At this point, the gases flow through the two gas turbine flow meters and the mobile calibration car in the seat. 3.7 After completing the online calibration, close the two ball valves of the calibration port, slowly open the forced seal ball valve of the comparison line, and slowly open the electric forced seal ball valve of the working road outlet (preferably, perform the four tasks at the same time).

3.8 Replace the flange blind plate and do not forget to close the ball valve on the flange blind plate. 3.9 At this time, the work route will be put back into work.