Abstract: A float type flowmeter including a bottom flow-through fitting and an upper flow-through fitting in spaced relationship with the bottom flow-through fitting; and an exchangeable measuring tube extending between the fittings. Each fitting has an opening formed as a cylindrical recess in alignment with each other with the openings each receiving a respective opposite end of the measuring tube. An external guide on each end of the measuring tube is in close fit with respectively an adjacent cylindrical recess, thereby facilitating axial movability of the measuring tube within predetermined limits in the longitudinal direction of the measuring tube. A distributor head having mutually communicating axial and radial ducts is located in the upper flow-through fitting closely above the upper end of the measuring tube; and a sealing closure screw operative in conjunction with an axial stop is provided for limiting the vertical axial movement of the measuring tube between the fittings.