Abstract: A measuring instrument for measuring mass of a flowing medium in which a measuring body extends across the flowing medium and has a rectangular flow channel through which the medium flows. The flow channel has a constricted inlet, a central portion with parallel sides and a widened outlet. A measuring element is supported in the measuring body such that the medium flows thereon. The measuring element carries temperature and heating sensors.

Abstract: The quantity of fuel in a fuel tank 1 is measured by determining the displacement of a membrane 19 and pressure values from a sensor 13. The displacement values of the membrane are representative of volume changes in a gas chamber in the tank 1 while the pressure values in the sensor 13 are representative of the pressure of the gas chamber. With these values, the fuel content in the gas tank can be determined from the general equation of state of an ideal gas. In order to displace the membrane 19, an electric motor 20 drives a step down transmission 25 which in turn drives a spindle mechanism 22 which is coupled to the membrane 19.

Abstract: Apparatus for measuring the quantity of fuel in a fuel tank of a vehicle wherein a chamber 41 is disconnected from tank 1 and connected to a fuel pump 4 after the measurement of the fuel quantity in the tank is conducted, the tank 1 being connected to the atmosphere, so that membrane 26 is displaced upwards to a defined position against the action of spring 27 by the fuel which flows into chamber 41 under pressure. The fuel in chamber 41 is then delivered into tank 1 for another measurement, the chamber 41 then being disconnected from fuel pump 4 and connected to tank 1 which is closed to the atmosphere.