Technical Maintenance Of Liquid Tank High-efficiency Filters in The Pharmaceutical Industry

Liquid tank high-efficiency filters have become the mainstream choice for high-grade clean areas (such as A/B grade) in the pharmaceutical industry due to their excellent sealing performance. Under GMP compliance requirements, the core of its technical maintenance lies in ensuring the integrity of its "liquid tank seal" is always online through precise monitoring and standardized ethics, eliminating any risk of leakage.
Based on the special requirements of the pharmaceutical industry, its technical maintenance system can be divided into four key links: daily inspection, professional testing, standardized replacement, and abnormal handling.

• Differential pressure monitoring: Daily or real-time monitoring of filter differential pressure is a direct indicator to determine whether it is clogged
•  Appearance inspection: Monthly check whether the liquid tank sealant (commonly known as "jelly glue") is sufficient, whether it has deteriorated, cracked or dented, and at the same time check whether the frame is deformed or corroded.
•  Replacement threshold: When the resistance exceeds 1.5-2 times the initial resistance (or reaches the set value such as 450Pa), replacement should be prepared.
• GMP correlation: Differential pressure data is an important component of the cleanroom environmental monitoring system and needs to be recorded and archived.

•  Integrity testing (PAO leak detection): This is a critical test that must be performed in the pharmaceutical industry, especially after the installation of new filters and during regular revalidation.
•  Leak detection method: Use an aerosol photometer to emit smoke (PAO) upstream of the filter and scan downstream. Scanning should cover the filter material, the sealing area between the filter material and the frame, and the most critical area - the sealing area between the liquid tank frame and the blade edge.
•  Standard procedure: Upstream concentration of 20-80 μ g/L, scanning speed of 3-5cm/s, sampling head distance from filter material of 2-4cm.
•  Acceptable standards: It is usually required that the filtration efficiency be ≥ 99.99% (H13 level and above) or the penetration rate be ≤ 0.01%. Any leakage point exceeding the limit must be marked and dealt with.
• Cycle: Usually conducted every 6-12 months or according to the GMP validation cycle.

•  Preparation work: Report to the production department in advance and prepare liquid tank filters of the same model. Before replacement, be sure to check the integrity of the new filter sealant.
• Disassembly and Cleaning: Shut down the system and carefully remove the old filter to avoid contamination spreading. Thoroughly clean the static pressure box and installation frame to ensure no dust or impurities.
•  Installing a new filter: Remove the protective film from the blade of the new filter, check that the sealant is intact, align it with the liquid tank, and install it vertically and steadily in place at once. It is strictly prohibited to make repeated adjustments to avoid damaging the sealant or distorting the gel, which may cause leakage.
•  Core principle: The installation process must ensure that the blade of the filter is completely and smoothly embedded in the sealing glue of the liquid tank, forming a reliable airtight seal.

• Leakage of sealing fluid: Check whether the liquid tank is damaged, whether the sealing gasket is aged, whether the position is correct, and replace it if necessary.
•  Filter efficiency decline: Firstly, perform PAO leak detection to confirm whether it is a filter material leakage or seal failure, and take targeted measures.
•  Abnormal pressure difference: Check for blockage (high pressure difference) or damage (low pressure difference), and make a comprehensive judgment based on air volume measurement
•  Verification requirements: Any repair or replacement must be retested for integrity before it can be put into use. |

• Regulatory compliance: All maintenance operations, including inspection, replacement, and testing, must have detailed records and logs, and be included in the company's GMP quality system documents. The certificate of conformity and other documents of the filter should also be properly stored.
• Personnel and safety: Maintenance personnel need to receive professional training and wear protective equipment during operation. The replaced old filter belongs to pollutants and needs to be disposed of according to medical/industrial waste regulations.
•  Environmental control: During the replacement of the filter, the pollution to the surrounding clean area should be minimized to the greatest extent possible, such as reducing personnel movement and door opening frequency.