The correct selection of ultrasonic flowmeters can ensure better use of ultrasonic flowmeters. The type of ultrasonic flowmeter to be selected should be determined according to the physical properties and chemical properties of the fluid medium to be tested, so that the diameter, flow range, lining material, electrode material and output current of the ultrasonic flowmeter can be adapted to the properties of the fluid to be measured. And flow measurement requirements.
1, precision function check
Accuracy levels and functions are based on measurement requirements and usage scenarios to select instrument accuracy levels for cost-effectiveness. For example, in the case of trade settlement, product handover and energy measurement, the accuracy level should be higher, such as 1.0, 0.5, or higher; for process control, select different accuracy levels according to control requirements; It is to detect the process flow, no need to do precise control and measurement, you can choose a lower accuracy level, such as 1.5, 2.5, or even 4.0, then you can use a low-cost plug-in ultrasonic flowmeter.
2, measurable medium
Measuring medium flow rate, meter range and caliber When measuring a general medium, the full flow rate of the ultrasonic flow meter can be selected within the range of 0.5-12 m/s of the measured medium flow rate, and the range is relatively wide. The selection of the meter specification (caliber) is not necessarily the same as the process piping. It should be determined according to 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 meter or the measurement accuracy is not guaranteed at this flow rate. It is necessary to reduce the gauge diameter, thereby increasing the flow rate inside the tube and obtaining satisfactory measurement results.
However, since the volume of condensed water in the wet steam is relatively small, the flow of excess water in the ascending pipe often appears as an annular flow structure, but when the amount of water is particularly large, it also appears as a ring with fibers. Flow structure. Among them, the fibrous fluid is actually a condensed water. Flow in a vertically descending pipe: In a vertically descending pipe, the structure of the gas-liquid two-phase flow is similar to that of a vertically ascending flow, but differs not only in the opposite flow direction but also in the case of the same average flow velocity. The flow rate of the liquid in the vertical drop pipe is much faster than the flow rate of the liquid in the vertical rise pipe.
Second, steam vortex flowmeter measurement considerations
Vortex flowmeters measure steam. Accurately arrange the steam traps accurately: People have long discovered that when the steam has more water, the vortex flowmeter will have a "leakage pulse" phenomenon, that is, in the case of a stable steam flow rate, the vortex flow It should have a stable pulse output proportional to the flow rate. But sometimes it is found that the output pulse of the meter is inexplicably less. The distribution of the output pulse recorded on the two-dimensional coordinates can also be clearly seen. The pulse that should be approximately evenly distributed is one less at a place. Pulses, in severe cases, are a lot less pulses, and in the worst case, there are no pulses at all. This may be related to the formation of a vortex column by impinging on a large volume of droplets having a non-uniform distribution on the vortex generator.
Battery powered electromagnetic flowmeter features
1. Micro power consumption design, five 3.6V lithium batteries, continuous operation for 5~10 years, and easy to replace the battery.
2. The display adopts LCD large-screen liquid crystal display, which can display multiple flow parameters such as instantaneous flow rate, flow rate (pipe pressure), cumulative total amount of forward and reverse, and alarm prompt.
3. There are no movable and resistance parts in the measuring tube, no entanglement or clogging phenomenon, almost no pressure loss, and long-term reliable and continuous work.
4. Wide measurement range: The flow rate measurement range can reach 0.05m/s~10m/s.
5. High measurement accuracy: ±0.5% ~ ±1.0%.
6. Measurement stability: The measurement accuracy is not affected by changes in physical parameters such as temperature, pressure, viscosity and density of the measured medium.
7, with pulse output and GSM wireless data remote transmission.
8, with data storage function, up to 1000 groups of traffic data can be saved, and the data storage time can be arbitrarily set and data query.