What Is The Working Principle Of A Three-way Valve?

The working principle of the three-pass valve is to change the connection of the fluid channel by moving the core inside the valve valve body to control the diversion or combination of media. Specifically:
I. Basic Structure three-way valve has three inlets and an outlet connected to the pipe, essentially combining two single-seat control valves into one. According to its working principle, three-way valve can be divided into three-way fusion valve and three-way diversion valve:
Three-way fusion valve: there are two inlet and one outlet, mixing two fluids. In a central air-conditioning system, for example, a three-way fusion valve mixes hot and cold water to adjust the temperature to the suitable level.
Three-way shunt valve: There is one inlet and two outlets that divide a fluid into two channels. In a heat exchanger system, for example, a three-way shunt valve distributes a fluid path evenly between two heat exchangers.
ii. The core function of the three-pass valve is the displacement of the valve core, which is used to adjust the opening ratio of two outlets (during shunt) or two inlets (during merger). Specifically:
Flow Dividing Applications: In the diversion application, the movement of the valve core can synchronize and reverse the opening of the three-way valve A and B, so as to realize the distribution of flow. For example, when the core moves upward, the opening for exit A increases and the opening for exit B decreases; conversely, the opening for exit B decreases.
Flow Combination Application: In flow combining application, the movement of the valve core can control the mixing ratio of two inlet media. For example, when the core moves to the right, the opening for inlet A increases and the opening for inlet B decreases, thus changing the composition or temperature of the mixture.
III. Drive Method Three-way valve has three driving modes: manual, pneumatic and electric:
Manual three-pass valve: the core is moved directly by a handwheel or lever, suitable for low frequency switching.
Pneumatic Three-Way Valve: driven by compressed air, the core driven by a pneumatic actuator. Pneumatic three-way valves has the characteristics of quick response and high adjustment accuracy, which is suitable for automatic control system.
Electric Triple-pass Valve: Driven by an electric actuator, valve core moves to receive signals from control instruments (e.g. 4-20mA DC, 0-10mA DC or 1-5V DC) and power sources for remote control and continuous flow regulation.
IV. INTRODUCTION Application Scenarios
Three-way valves are widely used in the field of industrial automation control fields, requiring fluid shunting, mixing and proportional regulation, such as:
Chemical and petroleum industries: used in key processes such as reactor temperature control, media proportioning and heat exchange systems.
Power industry: used in thermal recovery systems, equipment cooling, lubricant temperature control, etc..
Pharmaceutical and food industries: meet strict hygiene requirements for fluid process control and distribution, with high requirements for cleanliness.
HVAC systems: Used for regional temperature control and distribution of hot and cold media flow.