The secret of butterfly valve flow control: the art of rotation angle and fluid channel

1. Basic structure and working principle of butterfly valve
The butterfly valve is mainly composed of valve body, valve disc (also called butterfly plate), valve stem, sealing device and driving device. The valve body is the main body of the fluid channel, usually round or rectangular, and the internal design has a flow cross-section that matches the pipeline. The valve disc is a disc-shaped structure that can rotate around a fixed axis, and its edge is usually equipped with sealing materials to ensure that the valve can effectively prevent fluid leakage when it is closed.

The working principle of the butterfly valve is quite intuitive: the valve stem is driven to rotate by a driving device (such as manual, electric, pneumatic, etc.), and then the valve disc is driven to rotate in the valve body. The rotation angle of the valve disc determines the degree of opening or closing of the valve, thereby realizing the regulation of fluid flow. When the valve disc is completely perpendicular to the fluid flow direction (usually defined as 0° or fully open state), the fluid channel is the largest and the flow rate reaches the maximum; when the valve disc rotates to be parallel to the fluid flow direction (90° or fully closed state), the channel is almost completely blocked and the flow rate is almost zero.

2. Fine adjustment of rotation angle and flow control
The key to butterfly valve flow control is to accurately adjust the rotation angle of the valve disc. This adjustment process not only affects the amount of flow, but also directly affects the pressure stability of the system, fluid power loss and the service life of the valve.

Flexibility of flow regulation: As the rotation angle of the valve disc increases, the angle between the valve disc and the fluid flow direction gradually increases, and the channel area of ​​the fluid passing through the valve also expands. This change is continuous, which means that the butterfly valve can stay at any position between full open and full closed to achieve fine adjustment of the flow. This flexibility makes the butterfly valve particularly suitable for occasions where frequent flow adjustment is required, such as cooling systems, water supply networks, etc.
Dynamic balance of pressure and flow: While adjusting the flow, the butterfly valve also needs to consider the change of system pressure. By properly adjusting the rotation angle of the valve disc, the system pressure can be maintained stable while ensuring the required flow, avoiding pressure fluctuations caused by sudden changes in flow, and protecting downstream equipment from damage.
Control of fluid power loss: Changes in the rotation angle of the valve disc will also affect the power loss of the fluid when it passes through the valve. Although an excessively large opening angle can increase the flow, it may also increase the fluid velocity, thereby increasing energy loss and noise. Therefore, in practical applications, it is necessary to find the best balance between flow and power loss according to specific working conditions.
Sealing performance and service life: The rotation angle of the valve disc is also directly related to the sealing performance of the valve. Frequent opening and closing operations or improper rotation angles may cause wear of the sealing material, affecting the sealing effect and service life of the valve. Therefore, in design and operation, it is necessary to fully consider the impact of the valve disc rotation angle on the sealing performance, take necessary maintenance measures, and extend the service life of the valve.