Abstract: In a central air-conditioning system, regional flow balancing valves for controlling flow of water return branch pipes are arranged on the water return branch pipes, and energy balancing valves are arranged on water return pipes of tail-end fan coils respectively. A control method includes: detecting flow in the water return branch pipes, and adjusting the flow in the return branch pipes to be smaller than or equal to a branch pipe set flow value; and detecting the temperature of return water in the water return pipes of the tail-end fan coils, controlling the temperature of the return water in the water return pipes of the tail-end fan coils to be greater than or equal to a tail-end return water set temperature value, detecting the room temperature and adjusting the opening degree of the energy balancing valves in temperature controllers.

Abstract: In a central air-conditioning system, regional flow balancing valves for controlling flow of water return branch pipes are arranged on the water return branch pipes, and energy balancing valves are arranged on water return pipes of tail-end fan coils respectively. A control method includes: detecting flow in the water return branch pipes, and adjusting the flow in the return branch pipes to be smaller than or equal to a branch pipe set flow value; and detecting the temperature of return water in the water return pipes of the tail-end fan coils, controlling the temperature of the return water in the water return pipes of the tail-end fan coils to be greater than or equal to a tail-end return water set temperature value, detecting the room temperature and adjusting the opening degree of the energy balancing valves in temperature controllers.

Abstract: A control ball valve includes a valve body (1), in the valve body (1) is formed a flow passage for fluid to flow through, the flow passage comprises an inlet end (2) and an outlet end (5), the inlet end (2) is a conic channel with a gradually reducing inlet port. The ball valve can reduce flow resistance of the fluid flowing into the chamber of the valve body, reduce pressure loss, and avoid generating large turbulence.

Abstract: A high precision automatic flow balancing device comprises a flow balancing valve set at pipeline which is controlled by an actuator. A flow sensor at the same pipeline is connected to a control terminal. The control terminal compares the preset value with the output signals of sensors from each pipeline and gives a control signal to the actuator forming a closed control loop to control the flow of fluid.