Abnormal pressure and decreased purity of the nitrogen hydrogen air integrated machine are common laboratory malfunctions that require systematic investigation from three aspects: gas system, core components, and operating parameters.

The investigation of abnormal pressure should focus on the integrity of the gas path. If the pressure of hydrogen or nitrogen cannot reach the set value, the first thing to check is whether the gas circuit connection is loose or there is a leak. The soap liquid leak detection method can be used, with a focus on inspecting the sealing gasket of the drying tube, gas path joints, and welding points of the alarm. If bubbles are found to have emerged, it indicates the presence of a leak point. For the hydrogen system, it is also necessary to confirm the stable connection of the gas tank interface and check whether the hydrogen pressure regulator is faulty. If the regulator cannot maintain stable pressure, it needs to be replaced in a timely manner. If the device uses hydrogen batteries as the gas source, it is necessary to observe whether the black rubber pad of the battery protrudes, deforms, or leaks water. Such phenomena indicate that the battery is leaking and needs to be replaced immediately.

The root cause of purity decline is often related to the performance degradation of core components. When the purity of nitrogen is insufficient, priority should be given to checking whether the carbon molecular sieve of the nitrogen generator is poisoned or aged. If the air oil and water removal system is not maintained properly, oil stains will block the carbon molecular sieve adsorption chamber, resulting in a decrease in oxygen molecule adsorption capacity. At this time, it is necessary to replace the adsorbent and clean the air filter element. In addition, the aging of the oxygen probe of the nitrogen analyzer can also cause distortion of the detection data, and regular calibration or replacement of the probe is required. For the issue of hydrogen purity, the state of the electrolytic cell is crucial. If the electrolysis rate decreases or the gas purity decreases, it may be due to aging of the electrolysis material or damage to the separation membrane, and the electrolytic cell or separation membrane needs to be replaced in a timely manner.

The rationality of operating parameters cannot be ignored. When the nitrogen flow rate exceeds the design capacity of the nitrogen generator, the purity will significantly decrease, and the flow rate needs to be adjusted to the rated range according to the equipment specifications. At the same time, the adsorption pressure should be maintained between 0.65-0.85MPa. If the pressure is insufficient, the air supply capacity of the air compressor and the sealing of the pneumatic valve should be checked to avoid pressure loss caused by valve leakage.