Lug vs Flanged Butterfly Valve – Full Comparison Explained
Lug vs Flanged Butterfly Valve – Key Differences Explained
Table of Contents
- Introduction to Butterfly Valves
- What is a Lug Type Butterfly Valve?
- What is a Flanged Butterfly Valve?
- Lug vs Flanged Butterfly Valve – Detailed Comparison
- Butterfly Valve Diagram and Key Parts
- Butterfly Valve Symbol & HSN Code
- Butterfly Valve Uses in Industries
- Butterfly Valve Working Principle
- Butterfly Valve Actuator Options
- Stainless and Double Flanged Butterfly Valves
- Popular Brands: Delval Butterfly Valve
- FAQs
Introduction to Butterfly Valves
The butterfly valve is a quarter-turn valve used to regulate fluid flow in a pipeline. Known for its compact design, ease of operation, and quick shut-off capabilities, it is widely used in both low and high-pressure systems. This guide compares two popular types—lug type butterfly valve and flanged butterfly valve—to help you choose the right fit.
What is a Lug Type Butterfly Valve?
A lug type butterfly valve features threaded metal lugs around its body. These lugs allow the valve to be bolted directly between two flanges. The main benefit of this design is the ability to disconnect one side of the piping system without affecting the other, making it suitable for end-of-line service. These valves are ideal for isolation tasks, maintenance zones, and situations where temporary disassembly is required.
What is a Flanged Butterfly Valve?
A flanged butterfly valve has integrated flanges on both sides, which are bolted to the pipe flanges. This design provides robust support and is preferred in high-pressure and large-diameter pipeline systems. The secure bolting mechanism ensures minimal leakage and makes it ideal for applications that require durability and reliability over time.
Lug vs Flanged Butterfly Valve – Detailed Comparison
| Feature | Lug Type | Flanged Type |
|---|---|---|
| Design | Threaded inserts (lugs) for bolting | Integrated flanges on both ends |
| Isolation Capability | Can isolate one side without affecting the other | Requires full line disconnection |
| Application | End-of-line service, low/medium pressure | High-pressure and critical operations |
| Cost | Economical and easier to install | Higher cost but more robust |
Butterfly Valve Diagram and Key Parts
A typical butterfly valve diagram includes the following butterfly valve parts:
- Disc
- Valve Body
- Stem (or Shaft)
- Seat
- Handle or Actuator
Butterfly Valve Symbol & HSN Code
The butterfly valve symbol in P&ID diagrams is typically represented as a circle intersected by a straight line. This indicates a valve with a rotating disc mechanism. The official butterfly valve HSN code in India is 8481, applicable to stainless, flanged, and lug types.
Butterfly Valve Uses in Industries
Butterfly valve uses span across:
- Water treatment plants
- Fire protection systems
- HVAC installations
- Chemical and pharma units
- Oil & gas pipelines
Butterfly Valve Working Principle
The butterfly valve working principle is based on a disc rotating around a central shaft. A 90-degree turn of the handle or actuator opens or closes the flow. It allows for quick shut-off and minimal resistance in pipelines.
Butterfly Valve Actuator Options
Manual and automated controls are available. A butterfly valve actuator can be:
- Electric
- Pneumatic
- Hydraulic
Automation is useful in industries requiring remote operation or tight control.
Stainless and Double Flanged Butterfly Valves
The stainless butterfly valve is ideal for corrosive and hygienic environments such as RO systems and food processing units. The double flanged butterfly valve variant offers improved rigidity and leak-proof performance for high-pressure systems.
Popular Brands: Delval Butterfly Valve
Delval butterfly valve is known for industrial-grade quality and IS-certified products. These valves are available in both lug and flanged configurations and are trusted for municipal, building services, and factory operations across India.
FAQs
What is the key difference between lug and flanged butterfly valves?
Lug valves allow isolation of one pipe side; flanged valves offer a more rigid, high-pressure fit.
Where is a double flanged butterfly valve used?
It’s used in high-pressure systems, such as petrochemical lines and underground piping.
What does the butterfly valve symbol look like in diagrams?
A circle crossed with a perpendicular line—used in engineering drawings to depict valve type.
What is the standard butterfly valve HSN code?
HSN Code 8481 – used for GST and inventory classification of industrial valves.
Is a stainless butterfly valve better?
Yes, especially for corrosion-prone, hygienic, or chemical applications.
What actuator types are supported?
Electric, pneumatic, and hydraulic actuator types are compatible with both lug and flanged valves.
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