How are three-way valves used?

Three-way valves can be controlled by a regulated value or by a fixed value (%). Three-way valves play an important role in the analysis of fluid circuits. They divide the incoming fluid flow in a predetermined ratio. The valve position of a mixing valve is regulated by the control system. Depending on the situation in the system diagram, the three-way valve splits an incoming fluid flow or it merges two fluid flows. The output marked x is regulated. If the signal of the control is logically one, output x is fully open. The two situations are shown schematically in the following diagram: