How to Judge the Sealing Performance of Sanitary Butterfly Valves in Aseptic Workshops?

Aseptic workshops are core production areas in industries such as food, pharmaceuticals, and biopharmaceuticals, demanding extremely high levels of environmental cleanliness and media purity. Sanitary butterfly valves, as key equipment in the piping systems of aseptic workshops for controlling media flow and regulating flow, directly determine production compliance and product safety through their sealing performance. Substandard sealing performance of butterfly valves can lead to media leakage, contamination of the aseptic environment, material waste, production downtime, and even failure to pass authoritative certifications such as GMP and FDA, resulting in significant losses for the company.

Unlike butterfly valves used in ordinary workshops, aseptic workshops have much stricter sealing requirements for sanitary butterfly valves—they must achieve "zero leakage" to prevent media seepage and environmental contamination, while also preventing the release of harmful substances from the seals and the creation of unsanitary areas, ensuring media purity. However, many purchasing and maintenance personnel often do not know how to scientifically judge the sealing performance of butterfly valves during selection, acceptance, and use, easily falling into the misconception of "only looking at the brand and appearance." Today, we'll break down the methods for judging the sealing performance of sanitary butterfly valves used in aseptic workshops from three dimensions: selection, acceptance, and use. This will help you accurately control quality and avoid potential sealing problems.

I. Selection Stage: Control from the Source, First Check if the "Sealing Configuration" Meets Aseptic Requirements
The sealing performance of a butterfly valve in an aseptic workshop is largely determined during the selection process. When selecting, there's no need to blindly pursue high-priced products. Focusing on the two core configurations—sealing material and sealing structure—will allow you to initially determine whether its sealing capability is suitable for aseptic scenarios.

1. Sealing Material: Must Meet Food/Pharmaceutical Contact Grade Standards, Reject Ordinary Materials
The sealing of sanitary butterfly valves mainly consists of seat seals and shaft seals. The materials of both directly affect the sealing effect and hygiene safety, and are the basis for judging sealing performance.

For aseptic workshops, sealing materials must meet two core requirements: first, they must be resistant to media corrosion and high temperatures, suitable for the media (medicinal solutions, sterile water, culture media, etc.) and sterilization processes (such as steam sterilization) in the aseptic workshop; second, they must meet food/pharmaceutical contact-grade certification, with no harmful substances leaching out to avoid media contamination.

Common compatible materials and key points for judgment:
① EPDM (Ethylene Propylene Diene Monomer): Temperature range -40℃~150℃, resistant to steam, weak acids and weak alkalis, suitable for water and pharmaceutical solution transportation in most aseptic workshops; FDA and EC 1935/2004 certifications must be confirmed;
② FKM (Fluororubber/Viton): Stronger corrosion resistance and high temperature resistance (up to 200℃), suitable for highly corrosive media or high-temperature sterilization scenarios; authoritative contact-grade certification is also required;
③ PTFE (Polytetrafluoroethylene): Excellent corrosion resistance and meets hygiene standards, but prone to brittleness at low temperatures; suitable for aseptic processes without high temperatures or strong corrosion.

Common Misconceptions: Avoid using ordinary rubber seals. These seals lack sanitary certification, are prone to aging and releasing harmful substances, and have poor sealing performance, failing to meet the "zero contamination" requirements of aseptic workshops.

2. Sealing Structure: Prioritize "no dead angles, fully sealed" designs. The core requirements for the sealing structure of butterfly valves in aseptic workshops are "no sanitary dead angles, easy cleaning, and tight sealing" to prevent bacterial growth from residual media and ensure a tight seal for zero leakage.

Focus on two structural details: ① Valve seat structure: Prioritize "fully enclosed valve seats." The valve seat fits tightly with the valve body and ball, without gaps or dead angles, facilitating CIP/SIP online cleaning and sterilization and preventing media residue; ② Shaft seal structure: Employ a "dual-seal" design (such as packing seal + mechanical seal) to prevent media leakage from the valve shaft and to prevent external impurities from entering the valve body and contaminating the media.

Additional Reminder: When selecting a butterfly valve, ensure its sealing structure meets GMP requirements for "sterility and residue-free operation," avoiding the use of simple sealing structures with gaps and difficulty in cleaning.

1. Visual Inspection of Sealing Surfaces: No damage or defects are fundamental. After opening the butterfly valve packaging, first observe the appearance of the sealing surfaces (valve seat and ball sealing surfaces): ① The sealing surfaces must be smooth and flat, without burrs, scratches, or dents. Scratches or dents will cause poor sealing and leakage; ② The sealing components must be free from deformation, damage, and odor. If the sealing components are aged or deformed, even correct installation will not achieve effective sealing; ③ The connection between the valve body and the valve seat/spindle must be seamless and tightly assembled to prevent media leakage from the connection gaps.

2. Pressure Testing: Core Inspection, Verifying "Zero Leakage" Capability
Pressure testing is the most direct and crucial method for judging the sealing performance of butterfly valves. It simulates the actual working pressure of a sterile workshop to test the tightness of the valve's seal. The simplified procedure is as follows:
① Close the butterfly valve, seal both ends, and connect it to the pressure testing equipment;
② Inject sterile water (or clean air) into the valve body, slowly increasing the pressure to 1.5 times the actual working pressure and maintaining a stable pressure;
③ Observe for 30-60 minutes, focusing on checking the valve seat seal, valve shaft seal, and valve body connection for any leaks, sweating, or dripping;
④ If there is no leakage, the sealing performance meets the standard; if leakage occurs, contact the supplier immediately for replacement or repair.

Key Reminder: Pressure testing of butterfly valves in sterile workshops must use clean media (sterile water or clean air) to avoid impurities contaminating the sealing surface and affecting subsequent use.

3. Switching Flexibility Test: Indirectly Judging Sealing Fit
The switching flexibility of a butterfly valve indirectly reflects the sealing surface fit: ① When manually or pneumatically operating the butterfly valve, the opening and closing process should be smooth and stable, without jamming or abnormal noise; ② After closing the valve, if the handle/actuator is not loose, it indicates a tight sealing surface fit; if the valve jams, it may be due to misalignment or deformation of the sealing surface, leading to poor sealing; if it loosens after closing, media leakage will occur.

1. Observe for media leakage: During routine inspections, observe the sealing parts of the butterfly valve (valve seat, valve shaft) for any media leakage or dripping. Even slight sweating indicates a decline in sealing performance and requires immediate inspection.

2. Seal inspection after sterilization: Aseptic workshops undergo regular steam sterilization. After sterilization, check the butterfly valve seals for aging or deformation due to high temperatures. If seals are loose or detached, replace them immediately.

3. On/off status feedback: If the butterfly valve is found to be difficult to open or close, or if media continues to flow after closing, it indicates wear or misalignment of the sealing surface. Disassembly and inspection are necessary, and seals should be repaired or replaced promptly. Summary: Aseptic Workshop Butterfly Valve Sealing Assessment: Focus on 3 Core Dimensions

Assessing the sealing performance of sanitary butterfly valves used in aseptic workshops doesn't require complex equipment. A precise approach focusing on three dimensions—selection, acceptance, and usage—is sufficient:

1. During selection: Confirm that the sealing material has FDA/EC certification, the sealing structure has no dead angles, and it is suitable for aseptic environments;

2. During acceptance: Conduct visual inspection, pressure testing, and on/off flexibility testing to identify potential sealing issues;

3. During usage: Regularly observe the sealing areas, promptly identify sealing aging and wear problems, and perform proper maintenance.

Sealing performance is the "core competitiveness" of sanitary butterfly valves in aseptic workshops and is crucial for ensuring production compliance and product safety. As procurement and maintenance personnel, mastering the above assessment methods will allow you to avoid substandard products and select reliable, sterile-grade sanitary butterfly valves that meet aseptic requirements, thus building a solid "sealing defense" for aseptic workshop production.

If you have specific media or operating condition requirements during the selection and sealing testing of sanitary butterfly valves for aseptic workshops, please leave a message for consultation. We will provide you with professional assessment advice and adaptation solutions.