Middle-low pressure gas flowmeter with small caliber

Abstract

The invention relates to a middle-low pressure gas flowmeter with small caliber, in particular to a manufacturing technology of an ultrasonic gas flowmeter, which is used for detecting the flow of gas and is especially suitable for detecting the gas flow under the micro flow velocity. The gas flowmeter comprises an ultrasonic measuring stub and an ultrasonic measuring unit, wherein the ultrasonic measuring stub comprises a flange (1), a stagnation cavity (2), an ultrasonic transducer seat (3) and a current stabilizer (5). The flowmeter has the advantages that the ultrasonic measuring unit carries out the measurement on the gas through an ultrasonic transducer (4) vertically arranged on the ultrasonic measuring stub, the detection and metering can be started from less than 0.5m<3> / h, the detection area of the sonic wave reaches more than 25% of the area to be measured, the measurement precision of the integral measurement range reaches 0.5%, and the measurement range ratio is larger than or equal to 80 to 1, thus, the requirement for high-precision measurement is met.

Description

technical field [0001] The medium and low pressure small-diameter gas flowmeter relates to the manufacturing technology of an ultrasonic gas flowmeter, and is used for detecting gas flow, especially suitable for detecting gas flow at a small flow rate. Background technique [0002] With the advancement of industry and the continuous improvement of people's living standards, the use of various gas products such as natural gas and coal gas is increasing day by day, especially for a large number of industrial users and commercial users. Due to the control requirements of enterprise costs, small flow and small diameter (DN25mm to DN80mm) gas measurement and detection instruments have higher and higher requirements for accurate measurement. Accurate measurement of gas flow is of great significance for saving energy, saving production costs and improving product utilization. [0003] At present, the commonly used medium and low pressure small-caliber gas flowmeters at home and ab...

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Problems solved by technology

[0003] At present, the commonly used medium and low pressure small-caliber gas flowmeters at home and abroad (mainly distributed in DN25 to DN80) include: turbine flowmeter, positive displacement flowmeter, throttling flowmeter, ultrasonic flowmeter, electromagnetic induction flowmeter, mass flowmeter , Roots flowmeter, etc., due to the standard short-cut structure of this type of gas flowmeter, the accuracy level of this type of gas flowmeter for gas flow measurement is mostly below 1.0, and the measurement range is small (the range ratio is small, generally 5:1 to 20:1), and it is impossible to measure the flow rate of the gas in the state of small flow rate

In addition, affected by the flow field, this type of gas flowmeter needs to install straight pipe sections of different lengths in structure to improve the measurement accuracy of gas flow and increase the range ratio, otherwise it cannot be detected, and the installation of straight pipe sections This makes the small-caliber gas flowmeter subject to certain restrictions on the detection and installation requirements.

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