The center butterfly valve (also known as the centerline butterfly valve) is a valve with a disc-shaped butterfly plate as the core component. Its typical structural feature is that the valve stem axis, the butterfly plate center, and the valve body center completely overlap, forming a three-line coaxial design. This valve drives the butterfly plate by rotating the valve stem to achieve the on-off and flow regulation of the pipeline medium.
Core structure and working principle
Structural composition
Valve body: mostly made of ductile iron or stainless steel, with a cylindrical internal channel.
Butterfly plate: a disc-shaped structure, rigidly connected to the valve stem, and the material matches the valve body to enhance corrosion resistance.
Sealing ring: usually elastic materials such as rubber or polytetrafluoroethylene (PTFE), which rely on material deformation to achieve sealing.
Working principle
The butterfly plate rotates 90° around the valve stem axis. When fully open, the butterfly plate plane is parallel to the medium flow direction, and the flow resistance is minimal; when closed, the butterfly plate vertically cuts off the flow channel.
When adjusting the flow, a worm reducer is required to enhance the operating accuracy and self-locking ability.
Performance characteristics
Advantages
Simple and compact structure, low manufacturing cost, easy maintenance.
Suitable for pipelines containing suspended particles or powdery media. The butterfly plate can wipe the sealing surface when rotating to reduce impurity accumulation.
Disadvantages
Short sealing life: When in the long-term open state, the medium directly flushes the sealing ring, which is easy to cause wear or aging of the elastic material.
Limited application of small diameters: The flow resistance of specifications below DN200 increases significantly due to the increase in butterfly plate thickness, which affects the flow efficiency of the medium.
Typical application scenarios
Central butterfly valves are commonly used in low-pressure, normal temperature conditions, such as water treatment, HVAC systems and non-corrosive media control in the chemical industry. Its structural characteristics make it more cost-effective in large-diameter pipelines (such as above DN200).
