Core components include:
Valve Body: A short cylindrical section that connects to the pipeline.
Disc (Butterfly Plate): A disc-shaped element mounted in the center of the pipe, resembling “butterfly wings.”
Stem (Shaft): Passes through the center of the disc and connects to the actuator.
Seat (Sealing Ring): Ensures sealing performance when the valve is closed.
Actuator: Manually (handle, gear) or automatically (pneumatic, electric) controls the rotation of the disc.
A butterfly valve operates by rotating the disc to control the flow of fluid—either stopping, throttling, or allowing full flow. The core mechanism is a “rotational–flow-blocking” action.
Simplified explanation:
The disc, like a circular wing, is installed at the center of the pipeline.
It rotates around an axis perpendicular to the flow direction (usually only requires 90° rotation).
The disc’s position determines the degree of flow passage.
Detailed Operating States:
Fully Open (0°)
Disc is parallel to the fluid direction.
Allows maximum flow with minimal resistance.
Suitable for full-flow applications.
Throttling (0°–90°)
Disc is angled relative to the fluid direction.
Smaller opening increases resistance.
Used for flow regulation.
Fully Closed (90°)
Disc is perpendicular to the fluid direction.
Blocks the entire passage, stopping the flow.
Sealing ring contacts the disc to ensure tight seal.
|
Component |
Function |
|
Shaft |
Connects to the actuator and rotates the disc |
|
Disc |
Controls fluid flow or shutoff |
|
Sealing Ring |
Provides sealing performance when closed |
|
Actuator |
Drives operation: manual, pneumatic, or electric |
Fast opening/closing, requiring only 90° rotation.
Capable of continuous regulation or full open/close control.
Smaller and lighter compared to gate or ball valves.
By Structure:
Concentric (Centerline) Butterfly Valve: Disc and shaft are on the same centerline. Simple structure, cost-effective, suitable for low-pressure systems.
Eccentric Butterfly Valve: Includes single, double, and triple offset designs for improved sealing—ideal for medium to high pressure applications.
By Sealing Material:
Soft-Seated Butterfly Valve: Uses soft materials (e.g., rubber, PTFE) for sealing. Good corrosion resistance, suitable for low temperature and low-pressure conditions.
Metal-Seated Butterfly Valve: Metal-to-metal sealing, suitable for high temperature, high pressure, and corrosive environments.
By Actuation Method:
Manual: For small-diameter or low-frequency operations.
Electric: Ideal for remote automation.
Pneumatic: Fast response, common in automated systems.
“Centerline” and “soft seal” are the two key characteristics of this valve type.
Centerline Design:
The disc’s axis, valve body’s flow channel centerline, and sealing surface centerline align concentrically.
Simplifies the structure and reduces manufacturing costs.
Promotes even wear on the sealing ring during operation.
Soft-Sealing Definition:
Uses elastic materials (e.g., rubber, EPDM, NBR, PTFE) instead of metal for the sealing surface.
Relies on flexible contact between the sealing ring and disc for tight closure.
|
Component |
Material |
Description |
|
Valve Body |
Cast iron, stainless steel, PVC |
Withstands pressure and connects the pipeline |
|
Disc |
Cast iron, stainless steel, nylon-coated |
Controls flow or shutoff |
|
Sealing Ring |
Rubber, PTFE |
Provides flexible sealing and enhances performance |
|
Shaft |
Stainless steel, carbon steel |
Transmits torque to the disc |
|
Actuator |
Handle, gear, electric, pneumatic |
Controls valve actuation |
|
Advantage |
Description |
|
Excellent Sealing |
Elastic seat ensures tight fit and zero leakage under low-pressure conditions |
|
Compact Design |
Small footprint and lightweight—ideal for limited spaces |
|
Cost-Efficient |
Lower manufacturing cost, economically viable |
|
Quick Operation |
90° rotation enables rapid response |
|
Easy Maintenance |
Simple structure; sealing ring replacement is convenient |
Centerline soft-seated butterfly valves are applicable for the following common media:
|
Media Type |
Suitable |
Notes |
|
Clean Water / Tap Water |
√ |
Widely used in water plants and distribution systems |
|
Sewage / Rainwater |
√ |
Suitable for municipal drainage systems |
|
Air / Ventilation Gas |
√ |
Common in HVAC and ventilation pipelines |
|
Food-Grade Liquids |
√ |
Requires food-grade seals like EPDM |
|
Weak Acid / Alkali |
limited use |
Material selection must match chemical resistance |
|
Strong Acid / Alkali |
× |
Not recommended due to high corrosiveness |
|
High-Temperature Media |
× |
Not suitable above 80°C (some PTFE types up to 120°C) |
|
High-Pressure Media |
× |
Typically for pressures ≤ PN1.0~PN1.6 MPa |
Working Conditions:
Normal or low-pressure systems
Environments requiring tight shutoff or zero leakage
Applications needing quick open/close action
|
Industry / Scenario |
Examples |
|
Municipal Water Supply & Drainage |
Waterworks, pumping stations, underground networks |
|
HVAC Systems |
Air conditioning pipelines, ventilation systems |
|
Food & Beverage Processing |
Piping control, CIP systems (with food-grade materials) |
|
Light Industry & Environmental Engineering |
Water treatment, recirculating systems |
Temperature Limitation: Not suitable for media >80°C;
Chemical Compatibility: Select sealing material based on specific media (rubber types vary in resistance);
Seal Aging: Seals may degrade or harden with prolonged use or corrosive media—periodic inspection and replacement needed;
Not suitable for high-pressure or high-frequency actuation systems due to increased wear.
