Characteristics of multi-channel ultrasonic flowmeter online installation
Selection of multi-channel ultrasonic flowmeter for continuous flow online installation mainly depends on the following characteristics of the flowmeter.
(1) Higher Measurement Accuracy
Compared with other velocity type flowmeters, the dual-channel ultrasonic flowmeter is less sensitive to upstream obstacles such as elbows, pumps or valves, and the reliability of the measurement results is high, even if one channel stops working due to some reasons, the flow meter The measurement can still be continued. Typical requirements for straight inlet pipe sections are at least 5D upstream and at least 2D downstream. On the premise of meeting the above installation requirements, the measurement accuracy of the multi-channel ultrasonic flowmeter can reach ± 0.5%. Compared with this accuracy, the repeatability requirement of electromagnetic flowmeter is 1/3 of this accuracy, and the repeatability of ultrasonic flowmeter under this accuracy is 1/5 of this accuracy. Obviously, the requirements that ultrasonic flowmeter can achieve are higher than electromagnetic flowmeter .
(2) Lower requirements for straight pipe section
Because the multi-channel ultrasonic flowmeter uses double integrals to calculate the flow rate of the velocity distribution and area distribution, the flow rate can be accurately measured in the case of laminar flow and turbulent flow, which can achieve the accuracy of measurement handover, and at the same time can achieve flow measurement The range and measurement caliber are large, and the requirements for straight pipe sections are small (before 10D and then 3D). At present, the products on the market can achieve the largest applicable caliber of DN5000, and the larger the caliber, the easier it is to achieve high precision. The caliber can be made arbitrarily large in theory.
(3) Higher measurement sensitivity
Another feature of the multi-channel ultrasonic flowmeter is that because the time measurement accuracy is very high, it can reach the picosecond level, so it can achieve high measurement sensitivity, thus ensuring accurate measurement at low flow rates (0.5 m / s can reach 0.5 %). The range ratio is relatively high, up to 400: 1.
(4) Continuous flow and pressure construction and online maintenance can be realized
The plug-in ultrasonic flowmeter is different from the external clamp flowmeter, and its sensor directly contacts with the water (medium). As with other flowmeters, there is a factory-type pipe-type product with flange connection, and it can also be installed on-site on the pipeline used. Most plug-in ultrasonic flowmeters can achieve continuous flow and pressure installation through a pressure installation tool. This technology can be applied not only in old pipeline network renovation projects, but also in new construction projects, eliminating the need for expansion joints and connecting flanges If you install it after the pipe network is connected with water, you can save investment and construction period. After many years of use, the scaling of the pipe wall and the scaling of the front end of the sensor due to water quality problems may cause the signal transmission and reception of the sensor to be affected. At this time, the sensor can be removed from the sensor under constant flow through the online installation tool , Continue to ensure the accuracy and stability of the flowmeter measurement.
(5) Other features
Ultrasonic flowmeter also has a series of other features, such as no obstruction to the fluid, no pressure loss and flow loss, low power consumption; long service life, you can replace the transducer with continuous flow installation; low maintenance and operating costs; It can be powered by city power or battery. The problem of lightning strike introduced by the power supply can be solved well when the battery is powered; a full set of stainless steel is durable and beautiful.