Volumetric meter

Volumetric meter for measuring the output of a liquid flowing therethrough, which comprises a case having at least one aperture formed therein for introducing the liquid of which the output is to be measured, at least one liquid outlet aperture, and an inner circular channel connecting one inlet aperture to one outlet aperture, said liquid being led to flow through said channel for circulating from said at least one inlet aperture to said at least one liquid outlet aperture, a central member concentric to said circular channel which bounds internally said channel and is mounted for free rotation in said case, at least two pairs of diametrally opposite vanes pivotally mounted on, and rotatably rigid with, said central member, said vanes being distributed at spaced intervals on, and mounted at the outer periphery of, said central member between a first end position in which said vanes are retracted towards the center and another end position in which said vanes are spread radially outwards so as to close said channel in this other end position, said vanes being normally urged to said other end position by the pressure of the liquid stream flowing through said channel, and wherein each pair of successive vanes form therebetween in said channel, between one inlet aperture and one outlet aperture of said channel, a predetermined volume of liquid of which the output is to be measured, means for positively controlling the return of each previously spread vane to its retracted position after the vane concerned, during its pivotal movement in said channel, has bounded with the next following vane said predetermined volume of liquid, a diametral slide, rigid with said central member, operatively associated with each pair of diametrally opposite vanes, a toothed circular segment rotatably rigid with, and coaxial to, each vane, and a rack at either end of each diametral slide, each rack being in constant meshing engagement with the circular toothed segment of the associated vane, whereby the retraction of one towards the center of the meter will control the radial spreading of the diametrically opposite vane, said vice versa, and a shaft coaxial to and rotatably rigid with said central member, each revolution of said shaft corresponding to a predetermined output of the liquid flowing through said meter.