Aseptic Split Butterfly Valve are a type of industrial valve with a compact structure, excellent sealing performance, and convenient maintenance. They are commonly used in fluid control systems in industries such as petrochemicals, food processing, pharmaceuticals, environmental protection, and water treatment. Although their sealing structure is optimized and performs stably and reliably under most operating conditions, various forms of leakage problems may still occur during long-term operation, improper installation, or abnormal operating conditions. Leakage can not only lead to media loss and energy waste, but also cause equipment corrosion, environmental pollution, and even production accidents. Therefore, quickly identifying the source of the problem and troubleshooting it promptly is crucial.
This article will systematically analyze leakage types, common causes, quick troubleshooting steps, and preventive measures to help companies and users manage and maintain split-type butterfly valves (SBVs) more efficiently.
I. Types of Leakage in Split-Type Butterfly Valves (SBV)
In practical applications, SBV butterfly valve leakage is generally classified into two main categories:
- Internal Leakage
Internal leakage refers to leakage of the medium along the sealing surface between the butterfly plate and the sealing seat. It often manifests as the valve failing to completely shut off the fluid after closure, abnormal flow meter readings, and pressure failing to reach the set value.
Common symptoms include:
Slight flow persists after valve
Downstream pressure drops
Media crossflow causing system instability
- External Leakage
External leakage occurs outside the valve body and is a more obvious leakage phenomenon, usually concentrated at valve body joints, stuffing boxes, or connecting flange areas.
Common symptoms include:
Seepage or dripping on the outer surface of the valve body
Wet marks or crystals appear around the valve stem
Media overflow at the flange location
Understanding the type of leakage helps in quickly locating the root cause of the problem.
II. Common Causes of Leakage in Split-Type Butterfly Valves (SBV)
- Wear or Aging of Sealing Surfaces
The sealing surfaces of a butterfly valve are in constant contact with the medium, particles, or pressure fluctuations, which can lead to deformation, aging, hardening, or wear of the sealing rings.
Typical causes include:
High temperatures or corrosive media accelerate aging
Frequent opening and closing over a long period increases friction
Solid particles entering the valve cavity wear down the seal.
In this case, the valve may not close tightly, easily leading to internal leakage.
- Aging of Valve Stem Packing or Loosening of the Gland Sheet
The packing is used to prevent leakage between the valve stem and the outside environment, but after long-term use, the packing may:
Compress and deform
Aging and fail
Be corroded by the medium.
When the gland is loose or the packing is insufficient, external leakage will occur in the valve stem area.
- Leakage at the Joint Surface Due to Loose Valve Body Bolts
Aseptic Split Butterfly Valve (SBV) are assembled by bolts fastening the upper and lower valve bodies or the left and right valve bodies. If the bolts loosen under conditions such as vibration or high-temperature cooling cycles, it will lead to seal failure at the joint surface.
This manifests as slow leakage at the edge of the valve body, with the leakage increasing with increasing pressure.
- Improper Installation Leading to Concentricity Deviation
SBV butterfly valves have high requirements for installation concentricity. If:
The valve is not kept coaxial with the pipeline during installation;
Flange bolts are not tightened evenly;
The gasket is mismatched;
The butterfly plate may misalign with the sealing ring when closed, resulting in internal leakage.
- Medium Exceeding Valve Design Conditions
Valve designs are only applicable to specific pressures, temperatures, and corrosion levels. If these limits are exceeded, it can lead to:
Sealing ring expansion, contraction, or softening;
Butterfly plate deformation;
Valve body corrosion causing microporous leakage.
This is especially true for acidic or alkaline media, high-temperature steam, or slurries containing particles, which can accelerate valve wear.
- Improper or Loose Sealing Ring Installation
Some SBV butterfly valves have replaceable sealing rings. If they are not fully tightened during installation, are installed in the wrong direction, or the sealing ring dimensions are off, the sealing gap will increase, resulting in internal leakage.
- Actuator Failure Leading to Incomplete Closure
The following problems with electric or pneumatic actuators will prevent the valve from closing completely:
Incorrect stroke setting
Insufficient air pressure
Loose mechanical connection
Insufficient motor torque
These problems are common in automated production lines.
III. Quick Troubleshooting Methods for Split-Type Butterfly Valves (SBVs)
Through a systematic troubleshooting process, the location and root cause of the leak can be located quickly.
- Observe the Leak Location: Determine if it is an internal or external leak
Check for obvious leakage on the outside of the valve body
Is the downstream pressure dropping or the flow rate abnormal?
Confirm for crossflow using a bypass sight glass or pipeline instruments.
- Inspect the Valve Stem and Packing
If the external leak originates from around the valve stem, focus on checking the following:
Is the packing gland loose?
Does the packing need pressure replenishment or replacement?
Is the valve stem worn or corroded?
- Check the Valve Body Bolts
Use a torque wrench to check:
Are the bolts loose?
Is there uneven torque?
Are the gaskets compressed and ineffective?
This is especially critical for SBV structures.
- Check if the contact between the butterfly plate and the sealing ring is uniform.
This can be quickly determined by:
Manually operating the valve to confirm smooth opening and closing.
Listening for friction or scraping sounds.
Checking for eccentricity or misalignment.
Disassembling and inspecting the sealing ring for damage if necessary.
- Check the actuator stroke and torque.
Adjust the stroke limit.
Check if the air supply pressure meets the standard.
Check if the connection between the actuator and valve stem is loose.
If there is a leak in the automation system, the actuator is highly likely to be the problem.
- Check if the operating conditions exceed limits.
Ensure:
Temperature does not exceed the allowable range of the sealing material.
Pressure does not exceed the valve rating.
Media properties match the selected material.
Prolonged operation beyond the limits can easily lead to internal leakage.
IV. How to prevent the split butterfly valve (SBV) from leaking again? (Practical Suggestions)
-
Regular Maintenance Plan
Regularly check bolt torque
Regularly check seal wear
Regularly lubricate valve stem -
Select the Correct Material According to Operating Conditions
Choosing the appropriate sealing material is crucial, such as:
EPDM (suitable for water systems)
PTFE (corrosion resistant)
Viton (high-temperature resistant)
-
Ensure Installation Quality
Tighten flange bolts symmetrically and evenly
Keep the valve concentric with the pipeline
Do not forcibly pull the pipeline off-center -
Select Reliable Actuators and Control Systems
High-quality actuators can reduce the risk of incomplete closure. -
Avoid Operating Beyond Limits
If the medium contains particles, use wear-resistant seals or add filters.
Summary
While Aseptic Split Butterfly Valve are widely used industrial valves with stable structures and excellent sealing performance, leakage problems cannot be completely avoided. The root causes of leakage are mostly concentrated in areas such as seal damage, loose bolts, aging valve stem packing, improper installation, and exceeding operating limits.
The rapid troubleshooting methods described in this article can identify the location and cause of problems in the shortest possible time, allowing for appropriate repair measures to be taken. When combined with proper installation, regular maintenance, and suitable model selection, the service life and operational reliability of SBV butterfly valves can be significantly improved.
