Filter Bag Failure Analysis

Service Description

Symptoms of underperforming filter bags include a high-pressure drop, an increase in resistance to airflow, poor mechanical characteristics, and unacceptable particulate emissions. Forensic analysis of filter bags can bring to light many aspects of filtration failure.

Aokai Filter Bag Failure Analysis service focuses on five modes of failure: mechanical strength, chemical degradation, thermal degradation, dust penetration (media blinding), and incompatible design. Analysis takes place with the following procedures:

1 - Visual Inspection

● Examine the failed bags for visible signs of damage like tears, holes, abrasion, or caking.

● Assess the dust cake build-up and its characteristics (thickness, texture, adhesion).

● Look for evidence of chemical degradation or discoloration.

2 - Sample Collection

Collect representative samples of the failed filter bags, dust cake, and potentially other system components (cages, seals, housing) for further analysis.

3 - Laboratory Testing

The collected samples undergo various analyses depending on the suspected cause of failure. This could involve:

● Physical Property Testing: To assess tensile strength, air permeability, and other filtration parameters.
● Chemical Analysis: To detect chemical degradation or incompatible filter media materials.
● Microscopy Analysis: To identify wear mechanisms, fiber characteristics, and potential contamination.

4 - Data Analysis

Review operational data (pressure drop, flow rate, cleaning cycles) and process conditions to identify potential correlations with the observed failures.

5 - Reporting

Based on the collected evidence and analysis findings, a report is compiled outlining the identified failure mode, root cause, and recommendations for corrective actions and preventive measures.

By diligently conducting filter bag failure analysis, you can gain valuable insights into your filtration system’s health and ensure optimal performance, saving time, resources, and potentially preventing environmental non-compliance issues. A systematic approach involving these key steps will significantly enhance your understanding of filter bag failures and empower you to implement effective solutions.

Service Objective

Why filter bags are not performing as designed? Why differential pressure is abnormally high? Why the life span of filter bags is much shorter than expected? By understanding the root causes of filter bag failure, you can save significantly as filter bag replacement is one of the largest operating expenses for a baghouse system.

Filter Bag Failure Analysis is a systematic investigation to understand the cause of premature performance decline or damage in filter bags used within baghouse dust collection systems. It aims to identify the root cause of the failure to prevent future occurrences and optimize filtration performance and efficiency. The objectives include:

● Identify Specific Type of Failure:

This includes pinpointing whether the bags are suffering from tears, holes, blinding, chemical degradation, wear, or other issues.
● Determine Root Cause of Failure:

This goes beyond the immediate damage and digs deeper into the underlying factors that triggered it. Examples could be improper operation, incorrect filter media selection, design flaws, or incompatible process conditions.
● Recommend Preventive Measures:

Based on the findings, the analysis suggests corrective actions and improvements to mitigate similar failures in the future. This could involve changes in operating parameters, filter bag material or design, cleaning procedures, or even process alterations.
● Optimize Filter Bag Performance:

By understanding the specific reasons for failure, you can tailor the filtration system and operational protocols to maximize filter bag life and efficiency.

Tests & Analysis Included

Aokai Filter Bag Failure Analysis service includes Permeability Test,Tensile Strength Test, and Microscopy Analysis.

Permeability Test

Permeability Test measures the volumetric flow rate, measured in cubic feet per minute (cfm), through a square foot of filter media at a differential pressure of 0.5” water gauge (w.g.).

The measurement is performed on the filter in the “as-received” condition and after various cleaning steps, such as lightly snapping and brushing the filtration surface to simulate a cleaning cycle. The backside (clean side) of the filter media is vacuumed as the final step. An increase in the permeability indicates dust contamination.

Tensile Strength Test

Tensile Strength Test is a measure of the directional strength of the media, measured in pounds per square inch. The sample is secured in the testing machine and is pulled apart to the point of failure. A resultant load-displacement curve is developed which is then compared to new material for residual property characteristics.

Microscopy Analysis

Visual analysis of a filter sample is often aided by the use of a light microscope. In addition to observing the failure site, determining the particulate interaction with the filter media surface is often critical in solving filter media performance issues. Scanning Electron Microscopy (SEM) is also very helpful when investigating particulate and filter fiber surface morphology. Evidence of abrasion, chemical, and thermal effects is often enhanced during Microscopy Analysis.