Soft Seat Butterfly Valve is a type of butterfly valve that uses soft sealing material as the core component of the valve seat, and its design focuses on achieving low leakage rate and high adaptability through elastic sealing. The following is a description of the structure, performance and application dimensions:
- Definition and Core Structure
Core Definition
Soft Seat Butterfly Valve is a subtype of Soft Seal Butterfly Valve, whose seat is made of soft non-metallic materials such as rubber (e.g. NBR, EPDM), polytetrafluoroethylene (PTFE), etc., and achieves sealing by making elastic contact with the metal butterfly plate. Different from the metal-to-metal contact of hard seal butterfly valve, the soft seat design can compensate for trace deformation and improve sealing reliability.
Structural features
Seat form: divided into integral soft seat (seat and valve body integrated moulding) and replaceable soft seat (independent seat set in the valve body);
Butterfly plate configuration: mostly for the middle line or single eccentric structure, the edge of the butterfly plate is often designed as glossy or wrapped with anticorrosive coating (such as nylon), to reduce the risk of damage to soft materials. The edges of the butterfly plate are often designed to be glossy or covered with anti-corrosion coating (such as nylon), which reduces the wear and tear of the soft seat.
- Performance characteristics
sealing advantages
The elastic deformation ability of soft material can fill the microscopic gaps, and the leakage level can reach ANSI Class VI standard under normal temperature condition;
adapt to the slight vibration or thermal expansion and contraction of pipeline, reduce the risk of leakage caused by deformation.
Condition Adaptability
Temperature limitation: conventional rubber valve seat applicable temperature range of about -20 ℃ to 120 ℃, PTFE valve seat can be extended to -50 ℃ to 150 ℃;
media compatibility: corrosion resistance is better than metal seals, suitable for water, weak acid and alkali, oil and media containing particulate matter (e.g. sewage).
Operating characteristics
The opening and closing torque is about 30%-50% lower than that of hard seal butterfly valve, which is suitable for matching with manual worm gear or small pneumatic actuator;
Compression and permanent deformation of the soft seat may occur after long-term use, and the integrity of the sealing surface needs to be checked regularly.
- The typical application scene
Municipal and environmental protection engineering
As a cut-off valve in the water supply and drainage network, suitable for chlorinated water treatment environment;
sewage treatment plant for regulating the flow of fluids containing solid particles.
Industrial process control
Aseptic fluid pipelines in the food and pharmaceutical industry, using EPDM or PTFE valve seat to avoid contamination;
Low-pressure pipelines conveying corrosive media in chemical systems.
- The selection and maintenance points
Selection recommendations:
Priority for the replacement of the valve seat structure (such as clamping design), to facilitate the maintenance of the later stage; media containing abrasive particles need to increase the butterfly plate surface hardening treatment.
Maintenance specification:
Every 1-2 years to check the aging of the valve seat (such as cracks, hardness changes), high temperature conditions need to shorten the inspection period; avoid contact with mineral oil, strong oxidants and other media that lead to soft seat swelling.
With its high sealing and economy, soft-seat butterfly valve occupies an important position in low and medium pressure, corrosive or cleanliness demanding scenarios.
