Dispenser for fluent materials

Claim 1

A continuous flow dispenser for granular fluent materials, the dispenser comprising: a. a first, upper plate having a central axis and a plurality of substantially similar first orifices disposed about said axis and communicating in use with a hopper containing fluent material which is to be dispensed, the first orifices being spaced angularly apart at equal circumferential intervals about the central axis; b. a second, lower plate which is fixed with respect to the first plate and which has a central axis coincident with the central axis of the first plate and which is formed with a plurality of substantially similar second orifices spaced angularly apart at equal circumferential intervals about the central axis, the second orifices being circumferentially out of register with the first orifices so that each of the orifices in the upper plate is opposed by a solid portion of the lower plate; and c. an intermediate member which is disposed between and rotatable relative to the first and second plates about a central axis which is coincident with the central axis of the first and second plates and which is formed with a plurality of substantially similar third orifices spaced at equal circumferential intervals apart about the central axis, the number of third orifices being different from the number of first orifices and the number of second orifices and being neither a multiple nor a factor of the number of first orifices or the number of second orifices; the arrangement of the orifices being such that relative rotation of the intermediate member relative to the first and second plates causes the third orifices to move into and out of register with the first orifices and the second orifices so as to receive material from the first orifices and to dispense that material through the second orifices, and wherein the circumferential extent of the orifices in the plates and in the intermediate member is chosen with respect to the particular granular material to be dispensed such that the circumferential extent of each of the orifices in the upper plate is less than that of the opposed solid portions of the lower plate by an amount at least equal to the quantity 2t/tan r, wherein t is the spacing of the fixed plates and r is the angle of repose of the granular material to be dispensed, whereby direct flow of the material from the hopper through the first upper plate, the intermediate member and the lower plate is avoided, and whereby at all times during such relative rotation of said intermediate member in operation of the dispenser, material flow through the second plate is substantially continuous.