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
  • F04D29/00—Details, component parts, or accessories
  • F04D29/04—Shafts or bearings, or assemblies thereof
  • F04D29/046—Bearings
  • F04D29/047—Bearings hydrostatic; hydrodynamic
• • 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
  • F04D13/024—Units comprising pumps and their driving means containing a coupling a magnetic coupling
  • F04D13/025—Details of the can separating the pump and drive area
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/04—Shafts or bearings, or assemblies thereof
  • F04D29/043—Shafts

Definitions

• the invention relates to a magnetic drive pump comprising:
• a pump element provided with a first impeller driven in the form of a wheel rotatably mounted in a body associated with suction and discharge pipes,
• a drive motor provided with a transmission shaft on which is mounted a second drive rotor carrying a second series of magnets, the two series of magnets being arranged concentrically to achieve a magnetic coupling in rotation
• the sealing wall is particularly important when the pumped liquid has a corrosive character, which is frequently the case in chemistry or electroplating.
• the pumps currently used can be classified into two main categories:
• the motor 1 is connected to the centrifugal impeller 2 by an axis 3 and a rigid coupling device 4.
• the impeller 2 rotates in the pump body 5 which communicates with the suction 6 and discharge pipes 7.
• the leaktightness of the pump body when passing the axis 3 is ensured by the friction seal 8.
• a second potential defect concerns the seal itself which cannot be guaranteed in a perfect manner, due to the small surface defects that can be meet on the bearing surfaces in friction, and the inevitable creation of a liquid film between these surfaces.
• the driven rotor 22 secured to the wheel 12 is equipped with a series of magnets 23.
• the magnets 21, 23 are organized so that a north pole on the drive side is opposite a south pole on the driven side, and vice versa. A magnetic coupling is thus obtained without mechanical contact, coupling which must therefore be sufficient to withstand without lifting the maximum torque absorbed by the wheel.
• the device for positioning and guiding in rotation of the wheel 12 according to FIG. 2 consists of:
• FIG. 2 clearly shows the drawbacks inherent in the mounting of the axis 24 with regard to the precision, therefore the control of the games. Its positioning relative to the axis of the motor (with which it must theoretically be aligned), in fact passes through two parts whose precision and rigidity can pose a problem: the spacer 19 and especially the partition 18. We have seen in effect that the latter must be thin to pass in the air gap and not to produce too much eddy currents.
• the document FR-A-231 1201 describes a magnetic drive pump, in which the turbine is equipped with a magnetic core and is driven by the magnetic crown through a watertight partition.
• the rotary turbine is supported by a fixed shaft, which is guided by a pair of bearings on the magnetic ring in connection with the motor shaft.
• the presence of the bearings in addition to the output bearing from the motor shaft gives the assembly a significant overhang, and additional embedding.
• the axial size of the pump is important, and the positioning of the turbine shaft does not allow perfect alignment.
• the object of this patent is to propose a solution which makes it possible to remedy the above drawbacks, that is to say on the one hand to ensure perfect centering of the axis of rotation of the pump impeller, while unloading the bulkhead of this function, and on the other hand by seeking an efficient evacuation of calories to a cooling element.
• a female cylindrical bearing serves as a concentric housing for the tip to obtain a mechanical support and precise centering of the partition and the first driven rotor.
• the axis of the motor is advantageously extended by a length sufficient to allow it to enter the heart of the driven rotor.
• the axis of the motor includes the axis of the wheel which, when fixed, becomes rotating. It is obviously not this rotation which is sought, but the fact of having for the first driven rotor, a rigid support and perfectly aligned with the motor axis.
• the first driven rotor comprises a second ring which journals on a first ring secured to the fixed partition.
• the bearing integrated into the partition comprises at least one self-lubricating ring constituting a thermal bridge for the evacuation of the calories generated by the journaling of the first driven rotor towards the radiator formed by the motor shaft.
• the sealing partition should not be interrupted, it is therefore necessary to complicate its shape a little to make it bypass the extended nozzle, which belongs to the area external to the pumping circuit, while the axis 24 according to FIG. 2 of the prior art belonged to the internal area.
• the partition In addition to the cylindrical part present in the air gap, the partition must therefore have a second cylindrical part which engages on the end of the motor axis, with the interposition of a friction sleeve, made for example of self-lubricating material. .
• This axis now ensuring the positioning of the driven rotor with the desired precision and rigidity, this function no longer has to be provided by the sealing partition, which can therefore be significantly reduced.
• this partition can be made in one piece, in a material chemically compatible with the pumped liquid.
• the part must remain capable of withstanding the pressure of the liquid present around the driven rotor, a non-negligible pressure since it may be close to the discharge pressure of the pump. In cases where this pressure is high, and where there is no chemically compatible material having sufficient mechanical strength, it can be reduced to a mixed partition solution comprising a mechanically resistant outer shell, and a chemically compatible inner shell.
• the external envelope can therefore be much thinner, which makes it possible to envisage making it:
• the configuration described above has an obvious advantage, insofar as it reveals a thermal bridge of large cross section and thin between the bearing of the driven rotor and the shaft of the engine.
• this advantage is mitigated by the fact that it is necessary to evacuate in addition the calories produced by the rotation of the additional end piece of the motor shaft in its own bearing, but we are there out reaching the pumped liquid, which makes it possible to use conventional mechanical components, the performance of which is excellent.
• the sealing partition is shaped for chemical compatibility, while the precision and mechanical strength are ensured by an additional part partially matching the shape of the partition, and made of a material having a good mechanical strength.
• the additional part can be made of a metal alloy, in particular stainless steel, and includes a ferrule fitting into the air gap formed between the two series of magnets. The thickness of the ferrule is less than that of the enclosure of the partition.
• FIG 1 shows a schematic elevational view of a conventional motor pump assembly with friction seal.
• FIG. 2 represents a schematic elevation view of a conventional motor-driven pump unit with magnetic drive.
• FIG. 3 represents a view in elevation and in section of a magnetic drive according to the invention.
• FIG. 3 This embodiment is illustrated by FIG. 3 in which we find:
• the wheel of the first driven rotor 32 equipped with the first series of magnets 33 and a steel tube 37
• the second drive rotor 30 equipped with the second series of magnets 31 and a steel tube 38
• the tubes 37 and 38 having the function of ensuring the looping of the magnetic flux of the permanent magnets 31, 33.
• the tubes 37, 38 and the magnets 31, 33 are fixed respectively to the second rotor 30 and to the wheel 32 by any suitable means, in particular by overmolding, the fixed ring 35 and the rotating ring 36 constituting the rotation bearing of the wheel,
• a nozzle 42 extends the motor shaft 41, of which it can be an integral part, or on which it can be assembled with rigidity and precision.
• the nozzle 42 is arranged to receive the attachment of the second drive rotor 30, this attachment being provided by any suitable mechanical means.
• the sealing partition consists of a casing 48 made of material chemically compatible with the pumped liquid, and of a cylindrical shell 52 made of mechanically resistant material, in particular stainless steel. This ferrule makes it possible to provide resistance to internal pressure, insofar as the material constituting the envelope 48 may be insufficiently resistant.
• the envelope 48 is extended inwards by a part forming a sheath, into which the end piece 42 is introduced axially.
• the casing 48 carries: externally, the fixed ring 35, on which the wheel 32 is journalled, by means of its integral ring 36. internally, a steel sheath 53, in which will be fitted the self-lubricating rings 54, 54 'which engage themselves on the end piece 42.
• the ring 35 and the sheath 53 can advantageously be molded into the envelope of the partition 48 during the molding of the latter.
• the centering of the ring 35, and of the rotor wheel 32, is now ensured with precision by the end piece 42. This results in good concentricity of the parts 35, 53, 54, 54 ', and the play between the end piece 42 and the sockets 54, 54 'is very small.
• the sealing partition is therefore completely relieved of the centering function, and therefore no longer has to be very rigid. On the contrary, it is desirable for it to have a minimum of flexibility, so as not to interfere with the centering imposed by the end piece 42.
• the device of FIG. 3 allows good evacuation towards the outside of the calories generated by the rotation of the rotor wheel.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• External Artificial Organs (AREA)
• Electromagnetic Pumps, Or The Like (AREA)
• Sealing Devices (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9549645

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (18)

Family Cites Families (11)

• 1999
  • 1999-09-06 FR FR9911242A patent/FR2798169B1/fr not_active Expired - Lifetime
• 2000
  • 2000-09-06 WO PCT/FR2000/002446 patent/WO2001018401A1/fr active IP Right Grant
  • 2000-09-06 DE DE60006689T patent/DE60006689T2/de not_active Expired - Lifetime
  • 2000-09-06 ES ES00960799T patent/ES2211599T3/es not_active Expired - Lifetime
  • 2000-09-06 AT AT00960799T patent/ATE254723T1/de not_active IP Right Cessation
  • 2000-09-06 EP EP00960799A patent/EP1210520B1/de not_active Expired - Lifetime
  • 2000-09-06 JP JP2001521905A patent/JP2003508689A/ja not_active Ceased
  • 2000-09-06 US US10/069,358 patent/US6672818B1/en not_active Expired - Fee Related

Non-Patent Citations (1)

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