A precast slab gel for use in submerged horizontal electrophoresis is formed in a tray that includes a flat base and two raised walls on opposing sides of the base, the walls containing one or more tabs on their outer surfaces, the tabs mating with grooves in the interior walls of the tank. A stack device in a heat-driven type sound wave generating portion is provided at a one end of a resonance pipe. The mobile hose winding apparatus abandons the wall-mounted connecting mode of the conventional hose winding apparatus, and thus the apparatus according to the present disclosure can be moved as a whole for operation.