AN ELECTRIC SYNCHRONOUS PUMP WITH A VOLUTE HAVING A TANGENTIAL OUTLET

The pump (1) comprises : a supporting enclosure (2-4) incorporating a shaped body (3) to which there is connected a volute (4) having an axial inlet (5) and a tangential peripheral outlet (6) for the fluid being pumped, a single phase synchronous electric motor (7, 9) including a rotor (7) with permanent magnets which is rotatably mounted and can move axially and laterally in a chamber (8) formed within body (3) adjacent to the polar extremities (9a) of a stator (9) connected to the body, and a blade-bearing impeller (13) which is coupled in rotation to rotor (7) through a coupling (16) through which the rotor (7) can rotate under no load when the rotor (7, 9) starts up before the rotor drives the impeller (13) in rotation. Between rotor (7) and supporting enclosure (2-4) there is provided a ratchet coupling device (20) and a return member (28) which tends to press rotor (7) towards a coupled axial position in which ratchet device (20) is active and causes the rotation of rotor (7) to start up in a predetermined direction is associated therewith. The impeller (13) has blades (14) which are at least partly arched or inclined relative to the axial direction of the impeller (13) in such a way that as a result of interaction with the fluid rotation of the impeller (13) at a speed above a predetermined value is likely to cause axial lateral movement of the impeller (13) and rotor (7) relative to the body (3) against the force of the said return means (28). L'invention concerne une pompe (1) qui comprend : une enceinte support (2-4) comprenant un corps formé (3) auquel est reliée une volute (4) qui possède une entrée axiale (5) et une sortie périphérique tangentielle (6) pour le fluide pompé ; un moteur électrique synchrone monophasé (7, 9) comprenant un rotor (7) à aimants permanents qui est monté rotatif et qui peut se déplacer axialement et latéralement dans une chambre (8) formée à l'intérieur du corps (3) adjacente aux extrémités polaires (9a) d'un stator (9) relié au corps ; et une roue à aubes (13) qui est couplée rotative au rotor (7) par un raccordement (16) au moyen duquel le rotor peut tourner sans aucune charge lorsque le rotor (7, 9) démarre avant d'entraîner la roue (18) à tourner. Entre le rotor (7) et l'enceinte support (2-4) est disposé un dispositif à cliquet (20) auquel est associé un élément de retour (28) qui tend à presser le rotor (7) vers une position d'accouplement axiale dans laquelle le dispositif à cliquet (20) est actif et entraîne l