Mistake 3 Focusing Only on Accuracy Class, Neglecting Long-Term Stability—Parameter Supplement

Mistake 3 Focusing Only on Accuracy Class, Neglecting Long-Term Stability—Parameter Supplement

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　　Overemphasizing initial accuracy class while ignoring long-term stability leads to unexpected measurement drift in pitot probes, especially in harsh environments. Supplementing selection with stability parameters ensures consistent performance.Gas Pressure Scanwelcome to click on the website to learn more!

　　Accuracy class (e.g., 0.1% FS) reflects short-term precision, but stability—how well accuracy holds over time—depends on material and design. A 0.1% class stainless steel probe in a high-humidity environment may drift to 0.5% after 6 months due to corrosion, while a titanium probe with the same initial accuracy remains stable at 0.2%. A pharmaceutical plant learned this after replacing 50% of steel probes in cleanrooms due to drift, switching to titanium reduced replacements by 80%.

　　Stability testing involves 1000-hour continuous operation at 80% of maximum temperature/pressure. Probes with drift <0.1% over this period are preferred. A refinery specified this test for high-pressure pipeline probes, rejecting a batch that drifted 0.3%—avoiding costly flow measurement errors.

　　Material creep is a key stability factor in high temperatures. Inconel 718 probes showed 0.2% drift at 800°C over 1000 hours, while Haynes 282 probes (better creep resistance) drifted only 0.05%. For long-term turbine tests, this difference impacts data trending accuracy.

　　Selection should include both initial accuracy and stability parameters: 1) 1000-hour drift rate; 2) temperature cycling stability; 3) corrosion-induced error. This holistic approach ensures probes perform reliably throughout their service life.