the preventive measures for ultrasonic flowmeter zero drift

Here is the professional English translation of the preventive measures for ultrasonic flowmeter zero drift:

I. Installation & Environmental Control‌

Stable Temperature Environment‌

Maintain operating temperature within ‌-30°C to 160°C‌. Beyond this range, install temperature sensors for automatic acoustic velocity compensation ‌.

Avoid direct sunlight on probes; add thermal insulation to pipe exteriors ‌.

Vibration Suppression‌

Install flowmeter ≥20D (D=pipe diameter) from pumps/valves; reinforce pipe supports ‌.

Use elastic gaskets to isolate high-frequency vibration sources (e.g., compressors) ‌.

II. Operational Maintenance‌

Periodic Zero Adjustment‌

Manual Zeroing‌: With static full-pipe flow, execute zeroing via device menu (e.g., M42) if instantaneous flow ≠ 0 ‌.

Automatic Calibration‌: Enable weekly self-check for zero validation under no-flow conditions ‌.

Low-Flow Cutoff Setting‌

Set threshold to ‌0.03–0.05 m/s‌ to filter false micro-flow signals ‌.

Sensor Maintenance‌

Clean probe surfaces quarterly; replenish couplant semi-annually (ensure >95% acoustic transmission) ‌.

Inspect cable shielding integrity to prevent EMI-induced signal distortion ‌.

III. Fluid & Parameter Management‌

Medium Stability Monitoring‌

Switch to Doppler mode and recalibrate if bubble content >0.1% or suspended solids fluctuate abruptly ‌.

Manually input real-time density data if fluctuations exceed ‌±5%‌ to correct acoustic models ‌.

Dynamic Damping Adjustment‌

Increase damping coefficient to ‌3–5 seconds‌ in turbulent zones (e.g., downstream of pumps); reduce to ‌1–2 seconds‌ for steady flows ‌.

IV. Calibration & Upgrade Strategies‌

Scenario‌ ‌Action‌ ‌Frequency‌

Custody transfer (0.5-class) Factory recalibration + field verification Mandatory 1 year ‌

High-temp/corrosive media Upgrade corrosion-resistant probes + acoustic model 2 years ‌

Aging devices (>5 years) Capacitor testing + zero-drift module retrofit As needed ‌

Key Notes‌:

Perform initial zeroing after 72 hours of new device operation to eliminate stress deformation ‌.

Always verify static zero before restarting long-idle equipment ‌.

This integrated approach (temperature control, dynamic zeroing, fluid adaptation, and calibration) reduces zero-drift risk by ‌>80%‌ ‌.

(Translation retains original technical terminology, citation markers, and logical structure for accuracy. Units/metrics standardized to SI format.)