1. Structural design differences
| Type | Flange Butterfly Valve | Lug Butterfly Valve |
|---|---|---|
| Connection structure | The valve body comes with a complete flange, which is directly fastened to the pipe flange by bolts | The valve body has protruding ears (lugs) on both sides, and the ears contain through holes or threaded holes |
| Bolt layout | Bolts penetrate the valve flange and pipe flange to form an integral clamp | Split fixing: Short bolts connect the pipes on both sides independently without passing through the valve body |
| Sealing surface under pressure | The bolts squeeze the valve body, and long-term use may cause deformation of the sealing surface | Bolts only secure the lugs, preventing pressure on the sealing surface and extending service life |
2. Installation and Maintenance Features
Flange Butterfly Valve Installation:
Align the valve and pipe flange holes and secure with long bolts.
Disadvantage: Disassembly requires removing bolts from both pipes simultaneously, making maintenance inconvenient.
Lugged Butterfly Valve Installation:
Threaded Hole Type (Mainstream): Short bolts screw into the lug threaded hole to independently secure one side of the pipe.
Advantage: Allows removal of one side of the pipe (e.g., for maintenance) without the valve falling.
Applicable Applications: Pipeline ends, equipment discharge ports, and other locations where frequent disassembly and assembly are required.
3. Performance and Economy Comparison
| Items |
Flange Butterfly Valve |
Lug Butterfly Valve |
|---|---|---|
| Stability | Hight (integral flange structure) | The threaded hole type has the same stability as the flange type |
| Voltage rating | High(PN10-PN40) | Medium(PN6-PN16) |
| Cost | Higher (including flange and more metal materials) | Lower than flange type, higher than wafer type |
4. Typical Application Scenarios
(Insert application scenario card set here: chemical reactor outlets, fire protection pipe networks, food production lines, etc.)
Flanged butterfly valves are preferred for:
High-pressure (>PN16), high-flow steam/oil/gas pipelines;
Fixed pipelines requiring long-term maintenance-free operation.
Lug butterfly valves are preferred for:
Medium- and low-pressure (≤PN16) corrosive media (such as acid and alkali pipelines);
Conditions requiring single-sided disassembly, such as for end inspection ports and experimental equipment;
Space-constrained areas (threaded hole types offer more compact installation)
