The core feature of the concentric butterfly valve (also known as the center butterfly valve or the centerline butterfly valve) is that the valve stem axis, the butterfly plate center and the valve body center are completely overlapped, forming the simplest butterfly valve structure. Its essential characteristics are as follows:
1. Structural characteristics
Three-center-in-one design
The valve stem axis, the butterfly plate geometric center and the valve body center are completely overlapped, and the butterfly plate rotates symmetrically with the rotary axis as the center.
The butterfly plate is continuously squeezed and scraped with the valve seat during the entire opening and closing process, resulting in rapid wear of the sealing surface.
Sealing depends on elastic materials
Using soft valve seats such as rubber (EPDM/NBR) or polytetrafluoroethylene (PTFE), sealing is achieved through extrusion deformation.
Bubble-level sealing can be achieved at room temperature (leakage rate is close to zero), but the material properties limit the temperature resistance.
2. Performance limitations
Poor temperature resistance
The upper temperature resistance limit of soft sealing materials is ≤120℃, and aging, hardening or permanent deformation are prone to occur under high temperature conditions, resulting in sealing failure.
Low pressure resistance
The nominal pressure usually does not exceed PN16 (Class 150). Under high pressure, the sealing surface is squeezed more and the wear is accelerated.
Weak wear resistance
When the medium contains solid particles (such as sewage, slurry), the friction between the butterfly plate and the valve seat can easily cause scratches and leakage on the sealing surface.
3. Applicable scenarios
Advantageous working conditions
Low pressure (≤PN16), normal temperature (-10℃~80℃) clean medium (water, air, steam);
Scenarios that are cost-sensitive and do not require precise adjustment, such as building water supply and drainage, HVAC systems.
Typical applications
Municipal pipe network secondary water supply flow control (DN50~DN300);
Plant ventilation system air volume adjustment (no corrosive gas).
