1. Core structure and type
Structural composition
The three-way ball valve consists of a valve body, a ball, a valve stem, a seal and a drive device (handwheel, electric actuator, etc.). Its core is a ball with a channel, which can achieve flow channel switching by 90° rotation.
Classification and functional differences
T-type: three orthogonal pipes can be fully open or cut off to achieve diversion (one in and two out) or confluence (two in and one out); L-type: only connect two orthogonal pipes for medium distribution (such as switching flow direction); Y-type: designed with 120° or 135° diversion ports, suitable for medium switching (such as bypass control).
2. Workflow
Opening process
Initial state: When closed, the valve stem mechanically applies pressure to make the ball close to the valve seat, blocking the medium;
Drive rotation: Rotate the valve stem counterclockwise, the bottom angular plane releases the compression state between the ball and the valve seat, and the ball begins to rotate without friction;
Fully open position: The ball channel is aligned with the pipeline, and the medium flows freely.
Closing process
Reverse rotation: Drive the valve stem clockwise, the ball is separated from the valve seat and rotated 90°;
Sealing action: At the end of rotation, the valve stem mechanically wedges into the ball, forcibly pressing the valve seat to achieve Class VI sealing (leakage <100ppm).
Flow direction switching
T-type switching: When the ball rotates to the middle position, the three pipelines are partially connected to achieve flow distribution or mixing;
L/Y-type switching: Change the medium outlet path (such as main route to bypass) by rotating at a specific angle.
3. Drive and control mode
Manual operation
The handwheel directly drives the valve stem, which is suitable for small pipelines or low-frequency adjustment scenarios.
Electric control
The electric actuator receives DCS/PLC signals, accurately controls the rotation angle of the ball, and supports dynamic flow adjustment;
For example: the electric Y-type three-way ball valve links the ball through the valve stem to achieve automatic switching of A→B or A→C.
4. Sealing and pressure resistance characteristics
Sealing structure: metal hard seal (high temperature resistant particles) or soft seal (EPDM/NBR) is suitable for different media;
Pressure level: conventional models support PN16-PN40 (1.6-4.0MPa), and high temperature conditions require special material reinforcement.
5. Typical application scenarios
Chemical process: reactor raw material diversion, pipeline switching;
HVAC system: air conditioning hot and cold water flow direction adjustment, heating temperature control;
Water treatment: sewage treatment plant solid medium distribution, seawater desalination bypass switching.
The three-way ball valve achieves flexible control of the medium flow direction through the synergy of ball rotation and sealing. It has both fast response and high sealing performance, and is suitable for precise fluid management in complex industrial processes.