Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D13/00—Pumping installations or systems
  • F04D13/02—Units comprising pumps and their driving means
  • F04D13/021—Units comprising pumps and their driving means containing a coupling
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D13/00—Pumping installations or systems
  • F04D13/02—Units comprising pumps and their driving means
  • F04D13/06—Units comprising pumps and their driving means the pump being electrically driven
  • F04D13/0606—Canned motor pumps
  • F04D13/064—Details of the magnetic circuit
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D15/00—Control, e.g. regulation, of pumps, pumping installations or systems
  • F04D15/0077—Safety measures

Definitions

• This invention relates to synchronous electrical pumps, in particular for domestic electrical appliances.
• the invention relates to a synchronous electrical pump of the type defined in the precharacterising clause of appended claim 1.
• synchronous electrical pump 1 illustrated therein comprises a supporting enclosure 2 incorporating a shaped body 3 to which there is connected a volute 4 which has an axial inlet 5 and a radial peripheral outlet 6 for the fluid being pumped.
• Pump 1 has a synchronous electric motor incorporating a permanent magnet rotor 7 rotatably mounted in a chamber 8 formed in body 3 , between the polar extremities 9a ( Figures la and lb) of a stator 9 constructed of a stack of plates and connected to enclosure 2.
• At least one exciter winding in general single phase, is associated with stator 9, which in operation excites the poles of the stator simultaneously, conferring north polarity and south polarity magnetisation upon them alternately in time and space.
• stator 9 which in operation excites the poles of the stator simultaneously, conferring north polarity and south polarity magnetisation upon them alternately in time and space.
• rotor 7 is within stator 9, but the arrangement of these parts may be reversed.
• Rotor 7 is borne upon a shaft 10 which is rotatably mounted within body 3 through end bearings 11 and 12 ( Figure la) .
• Electrical pump 1 also comprises a rotor 13 which has a plurality of straight blades 14 which extend radially from a hollow hub 15.
• impeller 13 is connected rotatably to shaft 10 of rotor 7 through a coupling, indicated as a whole by 16 in Figures 2 and 2a, through which rotor 7 may be started up under no load before the latter drives the impeller in rotation.
• this coupling comprises a radial projection 17 from the rotor shaft and a projection in the form of an angular sector 18 which projects within the cavity of hub 15 of the impeller.
• the synchronous electric motor of a pump of the type described above produces a negligible torque on starting and also does not have a predetermined direction of rotation, being able to rotate in one direction or the other indifferently depending upon random starting conditions.
• One object of this invention is to provide a synchronous electrical pump of the type initially described which makes it possible to overcome the abovementioned disadvantages of pumps according to the prior art without making it necessary to adopt special complex and costly electronic control devices .
• This and other objects will be accomplished according to the invention through a synchronous electrical pump whose principal characteristics are defined in appended claim 1.
• Figure 1 already described, is a plan view of a synchronous electrical pump according to the prior art
• Figure la is a view in cross-section along the line la-la in Figure 1,
• Figure lb is a partial view along the arrow lb in Figure la,
• Figure 2 like that described, is a view in partial axial cross-section of a synchronous electrical pump according to the prior art
• Figure 2a is a partial view in cross-section along the line Ila-IIa in Figure 2,
• Figure 3 is a side view of a known ratchet coupling device which may be used in a synchronous electrical pump according to the invention
• Figure 3a shows the device in Figure 3 in an uncoupled condition
• Figure 3b is a view along arrow Illb in Figure 3
• Figure 4 is a side view of another ratchet coupling device of a type which is in itself known which may be used in a synchronous electrical pump according to the invention
• Figure 4a is a view along the arrows IVa in Figure 4,
• Figure 5 is a side view of a variant embodiment of a ratchet coupling device of a type which is in itself known which may be used in a synchronous electrical pump according to the invention
• Figure 5a is a view along the arrows Va-Va in Figure 5
• Figure 6 is a partial view in partial axial cross-section of a synchronous electrical pump according to this invention.
• Figure 6a is a view along the arrows Vla-VIa in Figure 6,
• Figure 7 and Figure 7a are two side views of a first impeller with mounted blades which may be used in a synchronous electrical pump according to the invention
• Figures 8 and 8a are side views of a variant embodiment of an impeller with mounted blades which may be used in a synchronous electrical pump according to the invention.
• Figures 9 and 9a are a plan view and a side view respectively of a tangential outlet volute which may be used in a synchronous electrical pump according to the invention.
• a synchronous electrical pump the rotor is mounted so that it can move axially with respect to the supporting enclosure and a ratchet coupling device of a type which is in itself known is provided between the said rotor and the said supporting enclosure. Return means tending to push it towards an axial coupled position in which the ratchet device is in operation and causes rotation of the rotor to take place in one predetermined direction only when running are associated with the rotor.
• a ratchet coupling I device 20 comprises a toothed wheel 21 which can rotate about a fixed axis 21a and is provided with a crown of saw teeth 22 and a pawl or ratchet 23 which can rotate about an axis 23a substantially parallel to axis 21a and acting together with a spring 24 (Figure 3b) .
• the arrangement is such that pawl 23 allows toothed wheel 21 to rotate only in a predetermined direction. Rotation in the opposite direction is prevented.
• the ratchet device is illustrated in the non- operating condition, in which pawl 23 is disengaged from teeth 22.
• Activation of the ratchet device is obtained through an axial displacement of either pawl or ratchet 23 or toothed wheel 21 so as to bring pawl 23 into the condition illustrated in Figure 3 in which it is engaged between two adjacent teeth of wheel 21.
• Figures 3 and 5 and associated Figures 4a and 5a illustrate two different embodiments of ratchet devices 20 with a coupling of the frontal type.
• toothed wheel 21 has a plurality of frontal saw teeth 22 with which at least one pawl 23, preferably of resilient material, for example an elastomer, projecting from a frontal surface of a member 26 which is coaxial with wheel 21 can act.
• the coupling between this member 26 and toothed wheel 21 also in this case takes place through a relative axial movement between them.
• a synchronous electrical pump according to the invention has a volute 4 with a substantially tangential outlet 6 , as for example illustrated in Figures 9 and 9a.
• the unit of the pump motor mounted with blades and the synchronous electric motor has the characteristics defined in appended claim 1, and will now be described in greater detail with reference to Figures 6 to 8a.
• parts and components which are essentially identical or equivalent to elements already described will be again allocated the same reference numbers as used previously.
• impeller 13 has blades 14 which are at least partly arcuate and are inclined relative to the axial direction of the impeller, for example as in the embodiments illustrated by way of example in Figures 7, 7a and 8, 8a.
• Rotor 7 with its corresponding shaft 10 is mounted with axial movement with respect to supporting enclosure 2 for the pump.
• shaft 10 of the rotor is mounted so that it can rotate and move axially in two end bearings 11 and 12 borne by corresponding supports 26 and 27 forming an integral part of supporting enclosure 2 (not illustrated in Figure 6) .
• End support 26 has a frontal pawl or ratchet 23 which is able to act together with frontal saw teeth 22 of a member 21 forming an integral part of rotor 7.
• a helical spring 28 is inserted between stationary support 27 and rotor 7, and tends to push the latter towards an axial coupled position (not illustrated) in which ratchet device 20 comprising toothed formation 21 and pawl or ratchet 23 is active and ensures that rotor 7 only rotates in a predetermined direction under operating conditions.
• the profiling or at least partial inclination of blades 14 of impeller 13 is such that, as a result of their interaction with the fluid, rotation of impeller 13 at a speed higher than a predetermined value is likely to bring about lateral axial movement of said impeller 13 and rotor 7 relative to supporting enclosure 2 of the pump, against the force of spring 28, so that rotor 7 takes up the axial position illustrated in Figure 6 in which toothed formation 21 is disengaged from ratchet or pawl 23, and ratchet device 20 is deactivated, while nevertheless allowing rotor 7 to continue to rotate in the aforesaid predetermined direction.
• impeller 13 is coupled to shaft 10 of the rotor by means of a delay coupling 16, of a type which is in itself known and already described previously.
• spring 28 will be dimensioned in such a way that it can apply a force to the rotor/impeller complex which is greater than the force due to friction between shaft 10 and bearings 11 and 12, but still less than the reaction force exerted by the fluid on impeller 13 when this rotates at a speed higher than the aforesaid predetermined value.
• a similar modus operandi is also achieved without the use of spring 28 by replacing the returning mechanical action of the same with a magnetic force attracting rotor 7 towards the terminal surface 9b of the poles 9a of the stator ( Figure 6) .
• This magnetic force can be produced by constructing the synchronous electric motor driving the pump in such a way that the frontal surface of the posterior extremity 7a of the rotor ( Figure 6) is suitably displaced in the direction of arrows C in relation to the terminal surface 9b of poles 9a of the stator.
• toothed formation 21 has two frontal saw teeth 22 which are angularly equally spaced apart.
• ratchet 23 is positioned between these teeth, with some angular play with respect to them.
• ratchet coupling device 20 may be provided between rotor 7 and support 27.
• the ratchet may be carried on the rotor, to act together with teeth 22 of wheels or stationary toothed formations .

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Medicines Containing Plant Substances (AREA)
• Grinding-Machine Dressing And Accessory Apparatuses (AREA)
• Automatic Analysis And Handling Materials Therefor (AREA)
• Cyclones (AREA)

Priority Applications (3)

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Publications (1)

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Family Applications (1)

Country Status (6)

Cited By (2)

Families Citing this family (1)

Citations (3)

• 2004
  • 2004-05-05 IT IT000016A patent/ITBG20040016A1/it unknown
• 2005
  • 2005-05-04 WO PCT/IB2005/051470 patent/WO2005106253A1/en not_active Ceased
  • 2005-05-04 DE DE602005022189T patent/DE602005022189D1/de not_active Expired - Lifetime
  • 2005-05-04 AT AT05740448T patent/ATE473372T1/de not_active IP Right Cessation
  • 2005-05-04 EP EP05740448A patent/EP1756428B1/de not_active Expired - Lifetime
  • 2005-05-04 ES ES05740448T patent/ES2348643T3/es not_active Expired - Lifetime

Patent Citations (3)

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