Thermal, Flow Measuring Device

A thermal flow measuring device for ascertaining a mass flow or a flow velocity of a medium in a pipe, comprising:

• at least one measuring transducer with at least a first and a second sensor element;
• and
• at least one heating means, wherein:
• said first sensor element has a pin-shaped metal sleeve, which has a lowest point on a wall of said metal sleeve in the gravitational direction;
• and
• there is arranged in said metal sleeve said at least one heating means, especially a heatable temperature sensor said heating means is arranged in said metal sleeve and above said lowest point in the gravitational direction, in such a manner that the maximum heat input per unit area from said heating means into the medium occurs in the gravitational direction above said lowest point.

A method for ascertaining a mass flow or a flow velocity of a gaseous and/or vaporous medium in a pipe by means of a thermal, flow measuring device, which includes at least one measuring transducer with at least a first sensor element which sensor element is embodied in such a manner that the first sensor element has a heating means, preferably a heatable temperature sensor, comprising the steps of:

• arranging the heating means in a pin-shaped shell, especially a metal shell;
• embodying the pin-shaped shell in such a manner that a liquid, which in measurement operation has deposited on the shell surface, can drain into a region, in which droplet formation occurs;
• and
• the heating means is in thermal contact with the measured medium and is arranged in such a manner in the shell that the maximum heat input per unit area into the measured medium from the heating means occurs above the region of droplet formation.