Precautions During the Verification and Operation of Scraper Flow Meters

With the advancement of economic globalization, crude oil—as a commodity—is increasingly integrated into international trade markets. As a critical component in crude oil transit trade, the measurement and handling of crude oil are receiving growing attention. The accuracy of crude oil trade-handover measurements directly impacts the economic efficiency of supply, sales, and transportation. Among the instruments commonly used for measuring and transferring crude oil, the scraper flowmeter stands out. This type of flowmeter employs mechanical measuring elements to continuously divide the flowing liquid into discrete volume segments, thereby accurately determining the total volume of the fluid—making it widely adopted in petroleum product measurement across China today.

Precautions during the Verification and Operation of Scraper Flow Meters

1. Verification Process: (1) To obtain accurate and reliable verification data, it’s essential to standardize the verification procedure. First, check the verification status and integrity of instruments such as thermometers and pressure gauges. Second, release the gas inside flow meters and volume tubes by venting through a directional four-way valve. Finally, inspect the outlet valve of the flow meter and the directional four-way valve for leaks, while also verifying the integrity of all associated pipelines. (2) Both parties involved in the handover should jointly supervise and verify the on-site data readings and entries to ensure the accuracy of the checked information.

2. Operational Aspects: (1) Since the flowmeter was put into operation and last verified, error adjustments have been made, and the error curve now shows a slight negative deviation trend. Currently, the flowmeter is calibrated every two months as agreed with the refinery. We are closely monitoring data changes to identify trends in the error curve and will subsequently reassess and adjust the calibration interval accordingly. (2) In practical operations, to minimize measurement errors and enhance accuracy, it is recommended to maintain consistent process conditions—such as temperature, pressure, and crude oil properties—during both the actual transportation and calibration procedures. This approach helps prevent significant fluctuations that could otherwise skew measurement results, ensuring accurate and reliable readings. (3) For the scraper flowmeter during operation, establish a routine maintenance schedule: lubricate the device with grease every two weeks and promptly clean the filter screen. These steps will help reduce wear on the flowmeter and mitigate the impact of impurities in the crude oil on measurement accuracy. Additionally, optimize the operational cycle and frequency based on the volume of oil being transported, avoiding prolonged or extreme operating conditions to minimize long-term performance degradation and associated losses.

In summary, analysis of historical verification data for scraper flowmeters reveals that the primary factors contributing to verification errors include measurement repeatability, as well as temperature and pressure conditions at both the flowmeter and the volume tube. To ensure the metering performance of scraper flowmeters and the accuracy of crude oil measurement handover data, it is essential to standardize the verification process and ensure precise data entry during verification. Additionally, in the later stages of operation, it is crucial to maintain consistency between the operational conditions during crude oil transportation and those present during verification. Establishing an effective operation and maintenance mechanism, monitoring trends in verification errors, and reducing the verification cycle are also key steps to uphold reliable measurement practices.