Looking at the 30-year development history of orifice flow meters

orifice plate flowmeterIt consists of an orifice plate throttling device, signal leads, and secondary instruments. Orifice flowmeter is the most researched, refined, extensively tested, experienced, and standardized measuring method both domestically and internationally. At present, there is still no unified standard for natural gas flow measurement. There are two parallel standards for measuring fluid flow using orifice flow meters, ISO5167-1 and API2530. Due to the differences in methods used for measuring natural gas between general and specialized methods, it has brought certain difficulties to China in formulating measurement standards for natural gas orifice plates.

China has always used orifice flow meters as the main flow measurement method in natural gas flow measurement. However, before the 1960s, there was no formal and unified measurement standard. In order to unify the measurement method and combine the characteristics of natural gas in China, the "Management Regulations for Installation, Calibration, and Use of Orifice Plate Measuring Devices for Measuring Natural Gas Flow (Draft)" has been formulated, which serves as the basis for measuring natural gas flow in China. This draft played a guiding and supervisory role in the natural gas extraction, transmission, distribution, and sales at that time. However, due to the lack of a formal natural gas flow measurement standard in any country to follow, there have been chaotic phenomena among natural gas users, such as arbitrary selection of measurement formulas and calculation parameters, unreasonable accumulation and value methods, rough processing of orifice plates, unreasonable installation, and inconsistency, which have led to disputes between supply and demand sides due to large measurement errors.
The SYL04-1983 "Standard Orifice Plate Measurement Method for Natural Gas Flow", officially approved in March 1983 and implemented in October 1983, is the first natural gas flow measurement standard in China. The promulgation and implementation of this standard have put an end to the long-standing lack of formal standards for natural gas flow measurement in China, especially for commercial natural gas flow measurement, and reduced measurement disputes.

More than 90% of natural gas flow measurement in China adopts standard orifice plates, and its standard SY/T6143-1996 "Standard orifice plate measurement method for natural gas flow" is based on ISO5167, with reference to AGA NO3 report and relevant standards. The significant changes in the flow measurement standards for these two orifice plates, especially the significant changes in the ISO5167 standard, have affected the revision of China's SY/T6143 standard. In order to adapt to the continuous development of measurement technology and standards, accelerate the integration of natural gas measurement with conventions in China, gradually implement quality based pricing, and in response to the new changes in natural gas orifice plate flow measurement technology and standards in recent years, in order to shorten the gap between China's natural gas measurement technology and standards and the level, the SY/T6143-1996 standard has been revised based on the experimental research results of nearly 20 years abroad, fully considering the particularity of natural gas media and the long-term practical experience of natural gas measurement in China. The revised standard name has been changed to "Measuring Natural Gas Flow with Standard Orifice Flow Meter", and the number has been changed to SY/T6143-2004.

2、 Development stages of secondary instruments
The secondary instrument of orifice flowmeter is a general term for measuring instruments such as pressure, differential pressure, and temperature detection components, as well as display and recording. The development of secondary instruments used in orifice flow meters can be divided into two stages:
1. * Stage - The stage mainly based on manual calculation. In the 1970s, the CWD-430 double corrugated tube differential pressure and static pressure recorder was widely used on site. The CWD-430 double bellows differential pressure gauge can not only display and record the differential pressure signals before and after the throttling device, but also record the static pressure at the upstream pressure tapping hole of the orifice plate. The CWD-430 double corrugated tube differential pressure gauge recorder, as a secondary instrument for orifice flow meters, is still used in metering stations, especially in China. It uses manual temperature measurement to obtain daily average temperature, radial root quadrature meter to calculate daily average differential pressure and static pressure, and calculator to calculate daily flow rate. The CWD-430 double bellows differential pressure gauge is a mechanical instrument, which has disadvantages such as low accuracy, multiple movable parts, inability to transmit data remotely, high susceptibility to human factors, and inconsistent calculation methods, often causing measurement disputes.

In the past 20 years, the research and development of energy-saving metering technology has given us various inspirations: the problem of strong electricity metering in high power consuming industries cannot be solved for a long time, and the main metering technology workers are bound by traditional metering concepts. Only after turning to the old metering concept to guide technology research and development, did we have the correct technical route and make breakthrough progress in research and development work. The method of online calibration of measuring equipment cannot confirm the comprehensive measurement of strong electricity. Modern industrial metrology must adopt a systematic online comprehensive measurement method for strong electricity. High power consuming enterprises consume a large amount of electricity, and a comprehensive economic and technical indicator of strong electricity involves multiple values and quantities. Its measurement involves multiple professions and cannot be completed by a single professional. The above is the insight we have gained from a major technical issue. However, from a management perspective, the research and promotion of energy-saving technologies involve the business of multiple management departments, but no department has come forward to organize and coordinate. At present, the promotion of energy-saving metering technology is difficult due to the division of administrative management system, which restricts the transformation of energy-saving metering achievements into real productivity. Today we pay tribute to Mr. Qian and revisit his speech at the National Conference on Metrology 30 years ago. He said, "Measurement work should be considered from the perspective of systems engineering; the transmission system and organizational system of measurement work are also systems engineering; administration can also use systems engineering methods; without the modernization of measurement work, it is impossible to achieve the four modernizations. Only by learning and inheriting Qian Lao's system engineering theory can we establish a modern scientific development concept of systems.