On the current domestic market, a variety of ultrasonic flowmeters, including those with four (sound) channels, six channels, and eight channels, either through-beam and retro-reflective in channel arrangement, are all claimed to be extremely adaptable to baffle interference and have shorter straight pipes than required by the national standard. To observe and study the tolerance of these gas ultrasonic flowmeters to typical baffle interference and the requirements on the length of the front straight pipe segment, our technical team, according to the process installation requirements of GB/T18604-2014 measurement of natural gas flow by gas ultrasonic flow meters, as well as the AGA NO.9 -2017 report, use the turbine working standard combination system as a flow measurement standard device to test the real flow of natural gas for representative DN100 gas ultrasonic flowmeters with A, B, C, and D channels and different arrangements. Testing process: First, basic data were obtained by testing under ideal pipeline conditions, and then a flow regulator is installed under the interference conditions of typical flow blocking parts (space elbow and manifold are located 30D, 20D and 15D upstream of ultrasonic flowmeter), and see whether the main technical indicators can meet the requirements of trade handover. The technical team of the author designed the test of the effect of different process installation conditions on the measurement accuracy of the gas ultrasonic flowmeter and put forward their own views on the basis of analyzing the test data.

The electromagnetic flowmeter is one of the most important hydraulic structures to measure the water flow in closed conduits. Based on the collected current and latest electromagnetic flowmeter standards at home and abroad, this paper gives a comparative analysis of the technical parameters of electromagnetic flowmeters, including product parameters, measurement parameters and metrological parameters, classified by product standards, measurement standards and metrological standards. The results show that there are some differences among the technical parameters of these standards at home and abroad. It provides helpful and reference value for understanding the requirements of revising standards.

The primary purpose of inter-laboratory comparisons is to demonstrate that the uncertainty specifications of the calibration measurement capabilities of the participating laboratories are correct. The most common criterion for assessing a participating laboratory’s results is whether the normalized error |Eni| is ≤ 1. Most comparison reports we reviewed properly include uncertainty components related to the transfer standard (uTs ) and the repeatability of the calibrations (urepeati ) in the uncertainty of the value reported by a participant. Unfortunately, high values for either uTs and urepeati decrease |Eni| , making it easier to achieve passing results in a comparison that uses a poor transfer standard or for a participant that delivers unstable measurements. A review of past comparison reports shows that this problem occurs for many measurands, including flow, temperature, and pressure. Improved comparison criteria were proposed by [1] to counteract the flaws of the |Eni| ≤ 1 criterion by introducing the possibility of inconclusive results and a probability-based approach. In this paper, we define comparison uncertainty ucomp as the root-sum-of-squares of uTs and urepeati and find it a better tool for assessing the power of the comparison than uTs alone. We applied the comparison evaluation criteria to recent comparison results to illustrate their benefits over the |Eni|≤ 1 criterion. In general, the newer criteria confirm prior determinations, but in some cases passing results for the |Eni|≤ 1 criterion would be found inconclusive.

Type approval testing of vehicles on chassis dynamometers, or experiments at the engine tests bench, require a precise measurement of the time-dependent fuel consumption, that is usually carried out by means of flow meters. However, the performance of these instruments can be jeopardized considering both the range of flow rate and its high dynamicity. In addition, the adoption of innovative fuels, such as biofuels and synthetic fuels, is nowadays of increasing interest thanks to their potential in pollutant emission reduction. Therefore, flow meters should depend as little as possible on the selected fuel, e.g. density and viscosity, and fuel temperature, guaranteeing high measurement accuracy in each test condition. In this context, the scope of the ongoing EMPIR Joint Research Project 20IND13 “SAFEST” is to investigate the measurementaccuracy of flow meters considering different fuels and different highly dynamic operating conditions. More specifically, in this paper the analysis on a Coriolis flow meter is presented. Flow measurements were carried out using different fuels in a wide density and viscosity range along with a broad temperature range.

Some gas flowmeters such as standard wet gas meter and critical flow Venturi nozzles are often used in the main standard of standard facility, and their accuracy is high, so its value transmission is particularly important. This paper introduces an active piston gas flow standard device. This paper introduces an active piston gas flow standard facility, which is composed of three active pistons and used in series. The measuring range can reach (0.01 ~ 128) m³/h, and the pistons can be automatically switched according to the required flow during the detection process. According to JJF 1586-2016 “Calibration Specification for Active Piston Provers”, analysis the uncertainty of the active piston flow standard facility. It can be obtained that the expanded uncertainty of the device is Ur(V) = 0.062 %(k = 2).Through the result of uncertainty evaluation, the standard facility can transmit the value to the gas flowmeter with higher accuracy level