Solution preparation device, and solution replacement system and method

A solution preparation device, comprising a liquid container, a powder container, an upper cover and a controller;

• wherein
• the liquid container is provided with a detection element for detecting a specific parameter of a solution;
• the powder container is arranged above the liquid container, the upper cover covers a top end of the powder container to form a material holding cavity for placing a powder, a bottom end of the powder container is provided with a material discharge port through which the powder in the material holding cavity enters the liquid container, and the upper cover is provided with a stopper for blocking the material discharge port;
• the controller controls the stopper to move up and down according to the specific parameter to realize opening and closing of the material discharge port;
• wherein the solution preparation device further comprises a stirring part provided in the material holding cavity for stirring the powder in the material holding cavity;
• the upper cover is provided with a telescopic part comprising a shaft, the stopper is provided at a bottom end of the shaft, and the stirring part is provided at a lower part of the shaft;
• and
• the stirring part comprises a multi-layer screen arranged along a length direction of the shaft such that the stirring part moves up and down along with the stopper.