Device for measuring the flow rate of fluids
The device comprises a tubular stator intended to be fixed in a pipe, so as to be traversed, in use, by said stream of fluid, and in which there is axially mounted a rotor which has a central hub from which extends a plurality of blades and which is capable of being operated in rotation by said stream, like a turbine, at a velocity variable according to the flow rate, and at least one permanent magnet integral with the rotor, disposed eccentrically with respect to the axis of rotation of said rotor. Fixed to the hub of the rotor is a shaped support bush mounted rotatable about a fixed pin or shaft which extends, projecting in the opposite direction to the operational direction of flow of the stream, from a central support integral with the axial outlet portion of the stator. The magnet is held in a housing defined between the support bush and the rotor.
1. A device for measuring the flow rate of a stream of fluid in a pipe, comprising a tubular stator intended to be fixed in the pipe so as to be traversed, in use, by said stream, a rotor axially mounted within the stator, the rotor having a central hub from which extends a plurality of blades and which is capable of being operated in rotation by said stream, like a turbine, at a velocity variable according to the flow rate, and at least one permanent magnet integral with the rotor, disposed eccentrically with respect to the axis of rotation of said rotor; there being fixed to the hub of the rotor a shaped support bush mounted rotatable about a fixed pin or shaft which extends, projecting in the opposite direction to the operational direction of flow of said stream, from a central support integral with the axial outlet portion of the stator; said at least one magnet being held in a housing defined between the support bush and the rotor.
2. A device according to claim 1 , wherein the support bush has a tubular portion fixed to the hub of the rotor and at least one transversely protruding portion, facing a rearward portion of the rotor; there being defined in said transverse portion of the bush a receptacle in which said at least one magnet is received.
3. A device according to claim 1 , wherein the support bush has a tubular portion fixed to the hub of the rotor; there being defined in a rearward portion of said rotor a receptacle in which said at least one magnet is received.
4. A device according to claim 1 , wherein the unit formed by the rotor and the support bush is axially translatable with respect to said shaft or pin and has stop means capable of butting against the free end of said shaft or pin under action of a thrust which, in use, is exerted axially on the rotor by said stream of fluid.
5. A device according to claim 4 , wherein the hub of the rotor has a blind cavity which extends in the rotor from its rearward side towards the forward side; there being fixed at the bottom of said cavity a small plate of wear-resistant material, intended to be disposed, in operation, in contact against the free end of said shaft or pin.
6. A device according to claim 3 , wherein said shaft or pin and the rotor are produced from wear-resistant materials.
7. A device according to claim 1 , wherein upstream of the rotor, there is connected to the stator a flow deflector comprising a plurality of angularly spaced, twisted fixed blades.
8. A device according to claim 5 , wherein upstream of the flow deflector a regulating member is disposed, having a plurality of angularly spaced openings; the angular position of said regulating member being adjustable relative to that of said deflector.