Float type liquid level gauge used for high temperature high pressure or low density medium

The utility model relates to a float type liquid level gauge used for high temperature high pressure or low density medium, which comprises a float chamber, a float and a scale; and is characterized in that: the float is a hollow ball; the liquid level gauge also comprises a guide rail and a magnetic coupling device; a magnetic steel or a circular sheet shaped magnetic steel is mounted in the magnetic coupling device in magnetic attraction with a magnetic material ball in the float of non ferromagnetic material, or with the circle sheet shaped magnetic steel in the float of non ferromagnetic material; a metal shaft is spanned between the sidewalls of the magnetic coupling device with both ends extended out from the sidewalls, attached tightly to the guide rail by magnetic force, while capable of moving up and down driven by the magnetic force; and loop resistance value variation can be measured by winding resistance wires on the guide rail to realize continuous remote signal transmission. The liquid level gau