Regarding the WEDEBAR flow meter
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Working principle of the WEDEBAR uniform flow rate sensor: Like other differential pressure type flow rate sensors such as orifice plates, the Wedebar also operates in accordance with Bernoulli’s equation. Where: Q = volume flow rate in the pipeline; K = flow coefficient; C = flow constant; DP = differential pressure. It can be seen that C is a constant, and to determine Q, it is necessary to determine K and DP. http://www.jncwell.com/images/g-15.jpgBasic principles and structural features of the Wedebar flow rate sensor:
Basic principles:
1) The cross-sectional shape of the uniform flow rate sensor, the surface roughness, and the location of the low-pressure pressure tapping holes are key factors determining the sensor’s performance.
2) The stability and accuracy of the low-pressure signal play a decisive role in the precision and performance of the uniform flow rate sensor.
3) The Wedebar flow rate sensor can accurately detect the average differential pressure generated by the average velocity of the fluid.
4) The Wedebar flow rate sensor has multiple pairs of pressure tapping holes arranged in a systematic manner in both high- and low-pressure areas, enabling accurate and stable measurement of the average flow velocity. http://www.jncwell.com/images/g-28.gif
Structural features:
1) Scientific cross-sectional shape
2) High-strength structure
3) Unique anti-clogging design
Features of the Wedebar flow rate sensor:
1) Capable of measuring various media, offering wide application ranges.
2) Excellent length accuracy.
3) Wide measurement range.
4) Pressure tapping holes that are less prone to clogging.
5) Surface roughening treatment and anti-sedimentation grooves on the sensor.
6) Multiple sets of pressure tapping holes.
7) High-precision flow coefficient.
8) Stable measurement signals with minimal fluctuations.
9) Low permanent pressure loss in the pipeline.
10) Low installation costs and virtually no maintenance required.
11) Possible for online installation and maintenance.
When fluid flows through the sensor, a high-pressure area is created in front of it, with a pressure level higher than the static pressure in the pipeline. Moreover, as the fluid flows through the acceleration section of the sensor, its velocity increases, resulting in a low-pressure area behind the sensor; the pressure in this low-pressure area is lower than the static pressure in the pipeline. As the fluid flows past the sensor, a partial vacuum is created behind it, and vortices form on both sides of the sensor. Advantages of WEDEBAR: (1) It can measure a variety of media, offering wide applicability. Media that can be measured include liquids, gases, and vapors. The range of pipe diameters that can be measured is from 8 mm to 12,000 mm. The pressure range for measurement is generally 0–210 kgf/cm2; in special applications, it can reach up to 420 kgf/cm2. The temperature range for measurement is usually from –100 to 505°C, with some special applications allowing temperatures up to 805°C. (2) It features high precision and a large measurement range. The precision of WEDEBAR is between ±0.5% and ±1.0%, while the precision of repeated measurements is as high as ±0.1%. The signal output is non-pulsating and thus extremely stable, as there are no moving parts in its structure ； The low-pressure port will not get clogged, allowing for stable signal acquisition ； The flow coefficient (K value) is linear, unlike in orifice or nozzle types, where it varies with the Reynolds number and flow velocity. The Weidiba flow sensor offers a range ratio of over 10:1 while maintaining an accuracy of ±0.5% to ±1.0%. (3) The pressure-taking hole of the sensor is resistant to clogging; a high-pressure area is formed in front of the Weidiba flow sensor (see figure), with a pressure slightly higher than the static pressure in the pipeline, which prevents particles from entering ； The low-pressure pressure taps are located on both sides at the rear of the sensor, in front of the fluid separation point and the wake region, and are not prone to being blocked by impurities caused by the vortex shedding forces generated by fluid flow. (4) The measurement signal is stable with minimal fluctuations. (5) Low permanent pressure loss in pipes: The cross-sectional shape of the Weidiba results in the least resistance, thereby resulting in the lowest permanent pressure loss for the fluid; this loss is generally only 3% of the differential pressure. Compared to orifice plates, nozzles, and Venturi tubes, energy consumption is reduced by over 95%, and the energy saved over one year is sufficient to recover the entire investment. (6) Low installation costs and virtually no maintenance required. Installing a Weidiba valve only involves making a small hole in the process pipeline; it requires just a few dozen millimeters of welding and several minutes of installation time. Advanced on-site installation equipment is available, allowing for installation without shutting down production. All valves or instrument connections require only simple assembly. The installation cost is at least 60% lower than that of orifice plates, and their service life exceeds that of the pipeline, with generally no need for maintenance. (7) Online installation for maintenance: For some measurement points where it is not possible to stop production for installation, as well as for media with high impurity levels, an online installation type can be used. Within the limits of flow rate, temperature, and pressure permitted by the sensor, installation and measurement can be carried out online without shutting down operations, and cleaning and maintenance can also be performed without interrupting production. WEDEBAR models: (1) WF10-100/110 – bimetallic ring expansion seal, threaded connection, universal type/dual-support type. Features: simple structure, cost-effective and practical. Applicable media: air, water, as well as other non-hazardous gases and liquids at normal temperature and pressure. It is particularly suitable for measuring cold air with pipe diameters not exceeding 1800 mm. Applicable pipe diameters: 38 mm to 1050 mm / 38 mm to 1800 mm. Standard grade: up to ANSI 300#, 2.9 Mpa at 396°C, 5.1 Mpa at 38°C. http://www.jncwell.com/images/g-29.gif (2) WF10-150 – safety-locking type, with wire expansion sealing and threaded connection. Features: The safety-locking threaded connection type is widely used and easy to install; the wire expansion sealing mechanism ensures good sealing performance even after multiple disassemblies. Applicable media: It is commonly used for measuring air, water, steam, and other non-flammable and non-explosive gases and liquids at temperatures not exceeding 300°C and pressures not exceeding 3.0 Mpa; it is particularly suitable for measuring the flow rate of medium and low-pressure steam. Applicable pipe diameter: 38mm–1800mm. Standard grade: up to ANSI 600# with 9.9 Mpa at 38°C and 5.8 Mpa at 396°C. http://www.jncwell.com/images/g-30.gif (3) WF10-200 – Wire expansion seal threaded connection, for online installation. Features: It allows for the installation or maintenance of probes without shutting down production; it is available in a single-rod drive version as well as a double-rod drive version for use in high-pressure conditions. Partial insertion can be chosen for cost reasons. Applicable media: It is commonly used for measuring media such as air, water, steam, and gas. It is particularly suitable for measurement points where shutdown for installation is not possible, or those with very dirty media that require regular maintenance. It is particularly suitable for measuring blast furnace gas and large-diameter underground circulating water. Applicable pipe diameter: 38mm–12000mm. Standard grade: During online installation, the temperature must not exceed 121°C and the pressure must not exceed 2.5 Mpa. Single-stem: ANSI 150#, 1.89 Mpa at 38°C, 0.65 Mpa at 39°C; Double-stem: ANSI 600#, 9.9 Mpa at 38°C, 5.8 Mpa at 396°C. http://www.jncwell.com/images/g-31.gif (4) WF10-400 – Metal wire expansion seal flange connection, designed for online installation. Features: Flange connection for improved sealing performance, as well as easy installation and disassembly. When users have high requirements for sealing performance as well as resistance to temperature and pressure, WF10-400 should be chosen; it is available in a single-rod drive version as well as a double-rod drive version for use under high pressure. For cost reasons, partial insertion can be chosen. Applicable media: Measurement of media such as air, water, steam, gas, and natural gas. Applicable pipe diameter: 38mm to 12,000mm. Standard grade: During installation, the temperature must not exceed 121°C and the pressure must not exceed 2.5 Mpa. Single-stem: ANSI 150#, 1.89 Mpa at 38°C, 0.65 Mpa at 396°C; Double-stem: ANSI 600#, 9.9 Mpa at 38°C, 5.8 Mpa at 396°C. http://www.jncwell.com/images/g-32.gif (5) WF10-500/510: Flanged type / double-supported flanged type, flange-sealed flange connection. Features: Simple structure, good sealing performance, and easy installation. Applicable media: Particularly suitable for measuring flammable and explosive media such as high-temperature and high-pressure steam, hydrogen, and oxygen. The WF10-510 is particularly suitable for measuring high-flow steam, as well as gases in circular and square tubes with extremely large diameters. For cost considerations, partial insertion can be chosen. Applicable pipe diameter: 38mm～12000mm. Standard grade: up to ANSI 2500#, 44Mpa at 38℃, 9.9Mpa at 482℃. http://www.jncwell.com/images/g-33.gif. Last edited by WSL01218 on 2009-3-9 12:36.]