An exterior gauge component is used to indicate a tank liquid level based on a rotational orientation of a tank magnet at a gauge head. The exterior gauge component includes a multi-track rotary encoder wheel and an optical sensor configured for reading an output of the multi-track rotary encoder wheel. The multi-track rotary encoder wheel is configured to rotate with rotation of the tank magnet such that specific ranges of rotational orientation of the tank magnet each corresponds to a specific output of the multi-track rotary encoder wheel. Each track represents a binary bit of the output read by the optical sensor. An adapter plate mounts a housing of the exterior gauge component to the gauge head and has an opening therethrough. A proximal end portion of the housing including magnets extends through the opening, and is detachable from the housing and attachable to a threaded adapter for mounting to a threaded opening of a tank.

An automatic liquid soap supplying system is provided with a plurality of soap dispensing main bodies for discharging a liquid soap, a plurality of soap dispensing components to be respectively connected to the soap dispensing main bodies, a liquid soap filling tank connected to each soap dispensing component, a mounting component provided with a photo display area of necessity for supplying liquid soap, as well as a control unit. In this case, a differential hydrostatic pressure is formed between the liquid soap filling tank and the soap dispensing component, whereby the liquid soap is filled into the soap dispensing component automatically from the liquid soap filling tank through the differential hydrostatic pressure. Moreover, the photo display area of necessity for supplying liquid soap is used to recognize whether supplement of soap is required, and air remained due to the supplement of soap is discharged via a exhaust valve.

A floating body is stored in a tank with a coolant and has a lower density than the coolant. A swing member is swingably supported and includes a contact portion which is displaced by being brought into contact with the tank and a to-be-detected portion which moves in an interlocking manner with the displacement of the contact portion. A sensor detects the floating body or the to-be-detected portion present at a detection position. The tank includes a restriction portion which restricts a movable range of the floating body to a range in which the detection position is a lower limit. By the attachment of the tank to the attachment portion, the to-be-detected portion is displaced from the detection position to an evacuation position in the interlocking manner with the displacement of the contact portion.

A tank includes an interior magnetic float assembly for detecting a liquid level in the tank, and an exterior gauge component attached to a gauge head of the tank for detecting and indicating the liquid level of the tank based on a rotational orientation of a tank magnet of the magnetic float assembly. An adapter plate mounts a housing base of the exterior gauge component to the gauge head. The adapter plate is secured to the housing base and snaps onto the gauge head. A portion of the base defined by a first molded piece extends within an opening of the adapter plate and a second molded piece of the base extends from the opening away from the housing to define a proximal end portion of the housing disposed proximate the tank magnet. Alternatively, the base receives a threaded adapter for mounting to a threaded opening of a gauge head.