Compressed air filters are not pressure vessels. Although the compressed air filter involves processing compressed air in its design and application, its core function is to purify the fluid by removing impurity particles, oil, etc. in the flowing medium through a filter screen or filter material. This is significantly different from the primary purpose and structure of a pressure vessel. Pressure vessels are mainly used to store and transmit high-pressure substances, such as compressed air, oil, gas, etc., and these substances are in a high-temperature and high-pressure state inside the container. Therefore, pressure vessels must use high-strength materials and undergo rigorous reinforcement and testing to ensure safety in high-pressure environments. In contrast, compressed air filters, while they may involve handling high-pressure compressed air, are designed to remove unwanted materials through filtration, not to store or transfer high-pressure materials. In addition, the structure of the filter is relatively simple and does not require reinforcement with high-strength materials because the pressure it withstands is usually within the design range.
In terms of design and material selection, although compressed air filters need to withstand the pressure of compressed air, they are generally made into a tubular structure with the filter element sealed in the shell. However, due to the pressure drop on the filter element during operation, it can be compared with the pressure of the air being processed. Ignoring it, the filter housing is a pressure vessel.
However, this does not change the fact that a compressed air filter is not a pressure vessel.
To sum up, although a compressed air filter may involve a certain amount of pressure when processing compressed air, its function and structure are essentially different from a pressure vessel, so a compressed air filter is not a pressure vessel.