Mingkai Environmental Protection Teaches You How to Understand Dust Collector Filter Bags

Mingkai Environmental Protection Teaches You How to Understand Dust Collector Filter Bags

A baghouse filter is a dry-type dust removal device suitable for capturing fine, dry, non-fibrous dust particles. The filter bags are made of woven filter cloth or non-woven felt, which filters dust-laden gas through the filtration effect of fibrous fabrics.

When dust-laden gas enters the baghouse filter, large and heavy dust particles settle into the dust hopper under gravity. As gas containing finer dust passes through the filter media, the dust is trapped, thereby purifying the gas.

Generally, the dust removal efficiency of new filter media is not high enough. After a period of use, a layer of dust accumulates on the surface of the filter bag due to mechanisms such as screening, collision, interception, diffusion, and static electricity. This layer is known as the primary dust layer. During subsequent operation, this primary layer acts as the main filtration medium for the filter media, enabling even filter media with relatively large mesh openings to achieve high filtration efficiency.

As dust accumulates on the filter media surface, both the efficiency and resistance of the dust collector increase accordingly. When the pressure difference across the filter bag becomes excessive, some fine dust particles already attached to the filter media may be squeezed through, reducing the dust collector’s efficiency. In addition, excessively high resistance of the dust collector will significantly decrease the air volume of the dust removal system. Therefore, timely ash cleaning is required once the dust collector’s resistance reaches a specified value. During ash cleaning, the primary dust layer must not be damaged, otherwise the filtration efficiency will drop.

The baghouse filter mainly consists of an upper casing, a middle casing, a lower casing (dust hopper), an ash cleaning system, and an ash discharge mechanism.

The performance of a baghouse filter depends not only on the proper selection of filter bag materials but also critically on the ash cleaning system. For this reason, the ash cleaning method is one of the characteristics that distinguish different baghouse filters, and also a crucial part in the operation of baghouse filters.