1. Clarify the medium characteristics and working conditions
Medium type and corrosiveness
Select the appropriate material according to the conveying medium (liquid, gas, steam or slurry containing particles):
Corrosive media (such as acid and alkali solutions) need to be made of stainless steel or alloy steel;
For media containing hard particles, it is recommended to use hard seals or wear-resistant coating designs.
Temperature and pressure range
High temperature environments (≤350℃) require high temperature resistant alloy valve bodies (such as 316L) or metal hard seal structures;
High pressure conditions (＞10MPa) require forged valve bodies and enhanced seal designs to avoid material deformation and leakage.
2. Determine the valve structure and function
Type selection
T-type three-way ball valve: suitable for diversion (one in and two out) or confluence (two in and one) scenarios, and can control the connectivity of three channels at the same time; L-type three-way ball valve: used to switch the flow direction of two vertical pipelines, suitable for medium distribution or reversing needs; Y-type three-way ball valve: 120° or 135° diversion design, suitable for bypass control or special angle flow regulation.
Connection matching
Select flange, thread or welding connection methods according to the pipeline interface to ensure compatibility with the existing system.
3. Operation mode and control requirements
Manual and automatic adaptation
Manual operation can be selected for low-frequency operation scenarios (such as routine switching in water treatment plants), which is low-cost and simple to maintain;
When integrated automatic control (such as chemical production lines) is required, electric or pneumatic actuators should be selected to support PLC/DCS remote control.
Dynamic adjustment accuracy
If real-time flow or pressure adjustment is required, an electric three-way ball valve with a positioner should be selected to support precise control of the opening from 0 to 90°.
IV. Sealing performance and reliability
Sealing grade requirements
Soft seals (EPDM/NBR) are optional for normal working conditions (water, oil), and the leakage grade reaches VI;
High temperature, high pressure or particle-containing media require hard seals (tungsten carbide/metal face seals) to withstand erosion and thermal expansion.
Safety redundancy design
Key systems (such as nuclear power plant cooling water) need to use explosion-proof actuators and be equipped with emergency shut-off functions.
V. Maintenance costs and long-term benefits
Maintainability assessment
Preferably choose modular design, support online replacement of valve seats, sealing rings and other wearing parts, and reduce downtime;
The flow channel needs to be cleaned regularly in solid medium scenarios, and it is recommended to use a full-bore structure to avoid deposition and blockage.
Brand and cost balance
For harsh working conditions (such as petrochemicals), it is recommended to use imported brands (such as KNKE in the United States) to ensure sealing and life;
For conventional scenarios, domestic high-cost solutions can be considered, but the material certificate and pressure test report need to be verified.
VI. Installation and adaptability verification
Space limitation: Compact L-type valves are suitable for areas with dense pipelines, and T-type valves need to reserve more operating space;
Flow direction verification: Before installation, the flow direction mark (A/B/C port) must be compared to avoid reverse connection and functional failure.
Through comprehensive media adaptability, functional requirements, control accuracy and full life cycle cost, the three-way ball valve model can be accurately matched to meet the efficiency and safety requirements of industrial processes.