the specified articles on pressure gauge maintenance and storage

Maintenance Steps for Pressure Gauge Transmission System‌

Maintaining the transmission system is critical for ensuring gauge accuracy and longevity. Perform the following steps periodically:

Clean gears and transmission components‌: Use a soft brush to remove oil residue and dust between gears to prevent jamming or pointer jumping.

Check mechanism flexibility‌: Manually test the smooth operation of segment gears, links, etc. Address sticking or wear immediately (e.g., clean rust or replace deformed parts).

Lubrication‌: Remove old grease and apply a minimal amount of specialized instrument oil (avoid mixing with contaminants to prevent viscosity buildup).

Calibrate transmission ratio and pointer‌: Adjust the error margin by rotating the driving arm at the tail of the transmission gear (clockwise to increase ratio, counterclockwise to decrease). Ensure nonlinear errors remain within tolerance.

Replace damaged components‌: If the hairspring is deformed, gears are worn, or the Bourdon tube is permanently distorted, replace the entire elastic assembly. Forced repairs are prohibited to prevent parameter deviation.

Precautions‌: Avoid forcibly unclogging damping holes or using non-compliant seals during maintenance, as this may cause hysteresis or leakage.

Precautions for Using Pressure Gauges in High/Low-Temperature Environments‌

Special protective measures are required in extreme temperatures to ensure measurement accuracy and safety:

I. General Precautions‌

Ambient Temperature Control‌

Standard gauges operate between ‌-25°C to 55°C‌. Beyond this range, use gauges with temperature-resistant materials/structures.

Shield gauges from direct sunlight (high temp) or cold drafts (low temp) using sunshades or insulation.

Range and Medium Requirements‌

Operating pressure should be ‌1/3–2/3‌ (standard) or ‌30%–70%‌ (specialized) of full scale to avoid elastic element damage.

Install diaphragm isolators for corrosive/viscous media.

Installation‌

Vertical mounting‌: Tighten with a 17mm wrench; never hand-tighten housings to prevent deformation/seal failure.

Vibration control‌: Use shock absorbers or snubbers if environmental vibration exceeds ‌25Hz frequency‌ or ‌1mm amplitude‌.

II. High-Temperature Measures‌

Overheat Mitigation‌

If the pointer fails to return to zero due to heat, cut the ‌rubber vent plug‌ at the top casing to equalize internal/external pressure.

Above 55°C, use ‌high-temperature gauges‌ (e.g., stainless steel Bourdon tube) or attach ‌heat sinks/thermal barriers‌.

Elastic Element Protection‌

Shorten calibration intervals to ‌every 2 months‌; replace parts if permanent deformation occurs.

III. Low-Temperature Measures‌

Freeze Prevention‌

Insulate‌: Wrap gauges and piping with foam or thermal blankets to prevent internal icing.

Drain liquids‌: Clear residual fluid before shutdown to avoid freeze damage.

Specialized Instruments‌

Below -25°C, use ‌diaphragm gauges‌ or ‌resistance transmitter gauges‌ filled with low-temperature silicone oil (rated -40°C).

Install ‌temperature compensators‌ (e.g., nickel-alloy sensors) to correct cold-induced deviations.

IV. Extreme Condition Protection‌

Risk Type‌ ‌Protection Measure‌

Pressure pulsation‌ Install pulsation dampers or pressure limit valves (per ASME B40.100); prefer ruggedized gauges.

Overpressure leakage‌ For gas media ≥2.89MPa or liquid ≥6.9MPa, use ‌safety casings‌ with pressure-relief backs.

Fogging/icing‌ Open oil vent plugs or use anti-fog gauges with rubber diaphragm compensation.

Emergency response‌: Replace immediately if the lens cracks, the pointer detaches from the stop pin, or the gauge exceeds calibration interval (>6 months).

Storage Guidelines for Long-Term Unused Pressure Gauges‌

Follow these procedures to preserve accuracy and lifespan during storage:

I. Pre-Storage Preparation‌

Depressurize & Zero‌

Ensure ‌zero pressure‌; the pointer must rest at zero. Never force-reset an offset pointer.

Drain residual liquid media to prevent freezing/corrosion.

Cleaning & Protection‌

Wipe the housing with alcohol-dampened cloth to remove oil/dust. Discard if the lens is cracked or stop pins are dislodged.

Sealed Packaging‌

Place in anti-static bags, then into original shock-proof boxes to prevent transit damage.

II. Storage Environment‌

Parameter‌ ‌Control Standard‌ ‌Risk Mitigation‌

Temperature‌ 5°C–40°C Keep away from heaters/cold sources to avoid thermal deformation.

Humidity‌ ≤75% RH Use desiccants to prevent gear rust or hairspring adhesion.

Light exposure‌ Total darkness UV light fades scale markings.

Corrosion‌ Isolate from acids/alkali Opt for 304 stainless steel housings for corrosion resistance.

Special gauges‌:

Remove and separately pack diaphragm isolators.

Extract batteries from digital gauges to avoid circuit corrosion.

III. Periodic Maintenance‌

Inspection Cycle‌

Check every 6 months for:

Pointer zero shift

Housing rust/condensation

Hardened/cracked seals.

Reactivation Test‌

Recalibrate at a metrology institution before reuse. Mandatory-certification gauges exceeding 6 months unused must be discarded.

IV. Prohibited Practices‌

❌ ‌Do not‌ store near vibrating equipment (e.g., compressors) to prevent internal gear loosening.

❌ ‌Do not‌ use standard rubber bags (sulfur emissions corrode metals).

❌ ‌Do not‌ stack gauges to avoid housing deformation or lens breakage.

Advanced recommendation‌: High-value precision gauges may be stored at accredited calibration agencies with controlled environments (20±2°C) and periodic calibration services.