Liquid surface sensing device

A liquid surface sensing device installed in a container having an opening in a ceiling part, the opening closed by a flange with a gasket constituted by an elastomer providing a seal between the flange and a peripheral edge of the opening, the liquid surface sensing device being assembled to the flange and comprising:

• a sensing unit disposed vertically below the flange and sensing a liquid surface of a liquid inside the container;
• a lead wire connecting the sensing unit to an external device via the flange;
• a guide bending the lead wire extending diagonally downward from the flange to form a valley portion to direct the lead wire diagonally upward;
• and
• a holder wall holding the sensing unit, wherein
• the guide protrudes from a surface of the holder wall,
• the guide and the surface of the holder wall define a hook portion at a diagonally downward side of the guide by which the lead wire is hooked,
• the surface of the holder wall is a planar surface,
• the guide includes:
• a first protrusion that bends the lead wire extending diagonally downward from the flange, and
• a second protrusion that guides the lead wire from vertically below to direct the lead wire diagonally upward, wherein
• the first protrusion defines a first flow passage through which a liquid composition dropped from the flange without traveling down the lead wire flows, and
• the second protrusion defines a second flow passage through which a liquid composition traveling down the lead wire to be accumulated at the valley portion flows, and
• the holder wall has a discharge groove placed outside of the first flow passage and the second flow passage.