Blowing is an important component of a good calibration procedure and should always be performed when handling hazardous gases. Blowing ensures that you can control the gas in the gas delivery system, thereby controlling which gases are exposed to internal components, sensors, or other equipment. It also helps prevent unnecessary reactions, greatly improving the service life of related components.

The main reason for blowing

1. Remove residual gas

When gases react with other compounds, they become more dangerous. A common result is that when some pure gases react with moisture in the ambient air, corrosive liquids are formed. These liquids cannot be completely removed by blowing like gases. This, in turn, can damage internal seals, valve seats, and threaded connections, leading to leaks and even catastrophic component failures.

2. Remove harmful gases

Many pure gases and gas mixtures are toxic, corrosive, or otherwise reactive and should not be left in gas delivery systems. Even the most durable wetting materials will eventually degrade in the presence of highly reactive gases. This can pose a danger to gas users and shorten the lifespan of components. In order to reduce the risk of safety accidents and extend the service life of system components, such gases should be replaced with appropriate purging gases after each use.

3. Remove impurities

Purification is also an important component of good calibration or analytical procedures, regardless of whether gases are harmful to health. The personnel performing calibration or analysis should ensure that the only gas reaching the sensing element is the gas to be measured or used for calibration. Before conducting analysis or calibration, all other gases should be replaced. In this case, the blowing gas is pure gas or a gas mixture itself.

Introduction to nitrogen purging

1. Application of special gas system purging nitrogen gas

(1) In the design of special gas supply systems, the purging nitrogen module design has become a standardized configuration. Generally, the commonly used purging gas is nitrogen. Of course, some users can also use inert gases such as argon as purging gas according to their own factory conditions.

(2) Inert gases generally use self purging systems.

(3) For flammable, explosive, toxic, and corrosive special gases, external nitrogen purging is required.

(4) For commonly used gases such as hydrogen and acetylene, it is also recommended to use external nitrogen for purging. On the one hand, this can ensure the cleanliness inside the pipe, and on the other hand, it can greatly improve the safety of use.

(5) To avoid secondary pollution to pipelines and valves, it is recommended to maintain the purity of nitrogen gas for purging at level 5 or above.

2. Precautions for using nitrogen purging

(1) The pipeline for blowing nitrogen must be equipped with a check valve;

(2) The purging nitrogen of incompatible special gas systems shall not share the same nitrogen source;

(3) The purging nitrogen of special gas systems with self ignition, flammability, toxicity, and corrosiveness should be connected to an independent nitrogen source and should not be connected to public nitrogen or process nitrogen systems.