Commonly used instruments such as gas chromatograph-mass spectrometers (GC-MS), electron microscopes, and gas analyzers require a reliable source of clean, dry gas for optimal function. High pressure cylinders are traditionally used to supply laboratory gases, but there are safety hazards associated with handling and storage.
Gas generators are considered a safer alternative, and they can provide various types of gas including nitrogen, hydrogen, and zero air at desirable compression, flow rates, and operating temperature. They provide uninterrupted gas supply, and unlike pressurized cylinders or tanks, do not have to be replaced once the gas runs out. Below are some tips to prolong the lifespan of your lab gas generators.
Regularly change your filters
Lab gas generators purify nitrogen gas from atmospheric air by filtering it through membrane filters to remove water vapor and particulates, and using activated carbon as molecular sieves to remove oxygen. Hydrogen gas is purified through electrolysis of water using a metallic electrode or ionomeric proton exchange membrane (PEM).
A PEM membrane allows hydrogen ions or protons to flow through, but not the resultant hydrogen and oxygen gases generated from water splitting. Hydrogen gas is finally extracted and purified by flowing the resultant gases through a series of membranes, desiccants, and activated carbon. Deionized water should be used to extend the longevity of PEM and gas generators.
As membrane filters are crucial to generate pure gases, it is recommended that they are inspected on a regular basis, depending on how frequently gases have to be generated and at what volume. Most manufacturers and service providers are able to recommend a maintenance schedule.
Maintain consistent operating temperature and humidity
Most lab generators are designed to work between 10-35°C. Temperatures outside this range may lead to increased pressure. To ensure that the operating temperature is kept in the recommended range, adequate airflow should be maintained around the generator to facilitate good ventilation. The vents should not be obstructed so that waste gases that are generated can be removed without any buildup of internal pressure. The gas generator should also be placed away from direct sunlight and in an air-conditioned room.
Gas generators are also designed to work at an appropriate humidity. When the humidity of atmospheric air is too high, it means that the various filter mechanisms such as desiccants have to work extra hard to remove water vapor. Users can use a hygrometer to check for humidity or place the gas generators in an air-conditioned room so that the air humidity is always kept low.
Compared to pressurized gas cylinders, gas generators have distinct advantages, such as being safer to use, easier to maintain, and cheaper. They provide uninterrupted gas supply and less batch-to-batch variation in gas quality for reproducible data collection. Simple maintenance, such as regular filter changes, can prolong the life of your gas generator.