Industry information

1. Issues with the Leak Testing Device

Insufficient sensor accuracy: Aging of pressure or flow sensors can cause fluctuation in measurement data.

Fluctuating air source pressure: Instability in the pressure from the air pump or source (e.g., pressure fluctuation, insufficient supply) directly affects the repeatability of the inflation or vacuum process.

Inconsistent valve response: Differences in the switching times of solenoid or control valves can cause deviations in inflation/exhaust times or pressure control.

2. Changes in Testing Conditions

Environmental temperature/humidity fluctuations: Changes in temperature can cause gas volume to expand or contract, and humidity changes may affect gas density or resistance in leak paths.

Defects in the sealing fixture: Gaps or uneven pressure on the contact surfaces of the workpiece and fixture, such as looseness or deformation.

Defects in the workpiece itself: Material deformation, residual liquid, or foreign objects (e.g., debris, oil) can cause temporary leakage changes.

3. Human Operation Factors

Insufficient or inconsistent force applied to the leak testing fixture.

Non-standard testing procedures (e.g., inconsistent inflation time, testing started before system stabilization).

1. Device Optimization

Regular calibration and maintenance: Calibrate sensors (e.g., pressure sensors, flow meters) on schedule and replace aging components (e.g., seals, valves).

Hardware upgrade: Use more accurate sensors and faster-response valves (e.g., piezoelectric valves).

Improve air source stability: Install pressure regulators, air tanks, or use high-precision air pumps to ensure stable supply pressure.

2. Control Testing Environment

Constant temperature and humidity environment: Place the testing area in an environment with controlled temperature and humidity, or use software algorithms to compensate for the effects of temperature/humidity (e.g., dynamically correcting leakage rate based on ideal gas equations).

Workpiece pre-treatment: Clean the workpiece surface to ensure no oil, debris, or foreign objects, and standardize clamping procedures (e.g., using pneumatic fixtures or torque wrenches to ensure consistent clamping force).

3. Standardize Operation Procedures

Standardized operation manual: Define parameters such as inflation time, balancing time, and testing cycle to avoid arbitrary adjustments.

Automation replacing manual operations: Use robots or automated fixtures to ensure consistent workpiece clamping and testing processes.

1. Sensor Nonlinear Response

Range Limit of the Detector: Pressure sensors typically have a limited linear range. At high pressures (e.g., >500kPa), the sensor may exceed its optimal operating range, leading to nonlinear error where the output signal diverges from the pressure value.

Temperature Drift: At high pressure, the sensor generates more heat, which, without adequate temperature compensation, may cause zero drift or sensitivity changes. This is particularly noticeable in designs without temperature regulation.

2. Sealing and Leakage Issues

Sealing Material Deformation: Under high pressure, sealing elements (e.g., O-rings) may be excessively compressed, causing permanent deformation or micro-leaks, particularly in low-hardness materials (e.g., silicone) that lack sufficient rebound under high pressure.

Structural Deformation: Detection chambers or pipes may experience slight elastic deformation (e.g., metal expansion) under high pressure, leading to volume changes that affect the accuracy of pressure decay calculations.

3. Gas Source Stability and Response Speed

Insufficient Pump Pressure Supply: At high pressures, the pump must maintain stable gas supply. If the pump lacks sufficient power or the air circuit is poorly designed (e.g., small pipe diameter), it can cause extended pressurization times or pressure fluctuations.

Valve Response Delay: At high pressure, the pump must maintain stable gas supply. If the pump power is inadequate or the air circuit is poorly designed (e.g., small pipe diameter), it can cause extended pressurization times or pressure fluctuations.

4. Changes in Gas Physical Properties

Impact of Gas Compressibility: At high pressures, the gas deviates from the ideal gas law (requiring correction with the Van der Waals equation), causing a larger deviation between the theoretical and actual pressure-volume relationships.

Adiabatic Effects: During rapid pressurization, the gas temperature rises (adiabatic compression), and during the test, the temperature gradually drops, causing transient interference in the pressure decay curve.

1. Hardware Optimization

Select High-Precision Sensors: Use sensors with a range covering high-pressure segments (e.g., 0-1MPa) and linear error ≤ 0.1% FS, and integrate temperature compensation modules (e.g., PT100 temperature sensors).

Enhance Sealing Design: Use high-pressure-specific sealing materials (e.g., fluororubber or polyurethane) or employ metal sealing structures (e.g., conical seals); add redundant sealing rings for safety.

Anti-Deformation Structural Design: Use thick-walled metal (e.g., stainless steel 316L) for the detection chamber and conduct finite element analysis (FEA) to verify deformation, or compensate for volume changes through calibration.

2. Improvements to Gas Circuit and Control System

Dynamic Temperature Compensation: Real-time temperature data collection to correct the temperature term in the gas state equation (e.g., using the Clapeyron equation).

Pressure Decay Model Optimization: Develop nonlinear leakage models for high-pressure gases (e.g., exponential decay fitting) to replace traditional linear approximation algorithms.

3. Standardization of Testing Processes

Extend Balance Time: Determine the thermal equilibrium time at high pressure through experiments (e.g., 30 seconds at 500kPa) and enforce waiting time in the program.

Segmented Testing Strategy: Apply different testing parameters (e.g., sampling frequency, leakage rate threshold) for high-pressure (>500kPa) and low-pressure segments to improve targeting.