EP2002126B1 - Rotary pump with coaxial magnetic coupling - Google Patents

Abstract

A centrifugal pump has static and closed housing/walling (1) for the feed liquid within the pump, and a contactless permanent-magnetic coaxial rotary coupling (6,7;13,14) for transmission of a drive torque within the pump housing. A pump impeller (4) forms an open unit with a magnet rotor (6). Between the magnet rotor (6) and a magnet driver (13) is a partitioning wall facing the opening of the pump drive-face, and the magnet driver (13) is mounted in at least one rolling bearing (16a; 16b) adjoining the pump.

Description

The invention relates to a centrifugal pump having the features of the preamble of claim 1, as shown in EP-B1-0171515 is known.

The centrifugal pumps with magnetic coupling represent an important type of industrially used machines for the conveyance of liquids. Compared to the simpler centrifugal pumps with mechanical seal they have the advantage of a hermetic seal of the pump chamber. This makes them especially favorable for the promotion of aggressive or toxic liquids.

In most cases executed coaxial rotary joints with radial arrangement of the magnets and corresponding radial magnetic action lines are used. Only this type is further considered below and is also the subject of the application.

The background of the invention will be described below with reference to FIG FIGS. 1 to 4 to the solutions known in the prior art explained.

Preliminary note 1: All drawings show an axial longitudinal section through the pump. The mostly cut rotational bodies were - with the exception of waves - for the sake of clarity without circumferential edges shown.

Preliminary note 2: For reasons of assembly and the various materials used, the component referred to below as the pump housing (1) must in practice be made up of several parts. Some of them are wetted by the liquid to be pumped and must be sealed accordingly, others not. For the sake of simplicity of illustration, the pump housing (1) is here shown in one piece.

A first known pump in conventional design is in FIG. 1 and is advertised, for example, in the brochure [1].

In the pump housing (1 ') a rotating pump impeller (4') is arranged, which receives the liquid to be conveyed via the suction nozzle (2 ') and ejects via the discharge nozzle (3') again under pressure.

The radial bearing of the pump impeller (4 ') takes place by means of an impeller shaft (5') usually in plain bearings (9 ', 10'), the fixed parts in a bearing insert (11 ') are added. The lubrication and cooling of the sliding bearing (9 ', 10') takes place by the liquid to be pumped itself.

The axial bearing of the pump impeller (4 ') and the other associated and rotating parts is not considered here and in the following. It is only indicated here that in addition to a mechanical bearing with thrust washers also hydraulic principles of action based on pressure differences, as well as a magnetic bearing can come into question.

The part of the rotary coupling which receives the driving torque through a partition, which is usually designed as a thin-walled containment shell (12 '), therethrough and via the impeller shaft (5 ') to the pump impeller (4') passes, is referred to as a magnetic rotor (6 '). This is equipped with permanent magnets (7 '), which in turn must be surrounded before the corrosive and possibly also abrasive attack of the pumped liquid with a cylindrical protective jacket (8') liquid-tight. It should be mentioned only marginally that it may be necessary to protect an approximately metallic, that is to say ferromagnetic, magnet rotor (6 ') from corrosion as well as the shaft (5').

The part of the rotary coupling which receives and transmits the driving torque of the motor via the drive shaft (15 ') is commonly referred to as a magnet driver (13'). He is also equipped accordingly with permanent magnets (14 '), but rotate in air and therefore are not subject to any special attack. The radial and axial bearing of the magnetic drive takes place in commercial rolling bearings (16 ').

Another common design, especially for smaller pumps, shows FIG. 2 , Such a pump is advertised eg in [2].

With this construction, a bearing insert (11 ') can be inexpensively eliminated. The pump impeller (4 ') is combined with the magnet rotor (6'), the permanent magnet (7 ') and the protective jacket (8') to a part. This rotating impeller magnetic rotor unit (19 ') is slidably mounted here on a fixed axle (17'). The axis (17 ') itself is fastened on one side via flow ribs (18') in the suction nozzle (2 '), supported on the other side in the specially shaped containment shell (12').

In the FIG. 1 and 2 described and today largely conventional construction (referred to here as type A) is characterized in that the magnet driver (13 ') is arranged radially outwardly over the further inside magnetic rotor (6'). This design has the advantage that the high moment of inertia of the outside magnet driver (13 ') counteracts the too rapid startup of the driving motor and thus the tearing of the magnetic coupling can be prevented more favorable.

Furthermore, this design facilitates in particular a generously axially spaced radial bearing of the pump impeller (4 '), which is always desirable due to the high hydraulic forces within the pump.

On the other hand, magnetic coupling pumps with a magnet rotor (6 ') located radially on the outside, which is in contact with the liquid, and an internal magnetic driver (13') are less frequently used. This embodiment is referred to as type B.

Such pumps of type B, for example, in the DE 01453760 or EP 0171514 or EP 0171515 , are described and in FIG. 3 are shown, must be carefully designed so that the magnetic coupling does not break during rapid startup, which threatens here due to the outside magnetic rotor (6 '). Furthermore, the radially inner magnet driver (13 ') obstructs an axially pulled-out inner slide bearing of the impeller magnetic rotor unit (19'), if not the containment shell (12 '), with its actual opening in the type B drive side must be facing the pump, adversely wound right is executed. An executed pump type B is advertised in [3] and served as a template for the FIG. 3 , That here in contrast to the construction entspr. FIG. 2 the axis (17 ') is held solely by the flow ribs (18'), has in the running pump the advantage of a consistently thin-walled split pot (12 '), which is charged only with the internal pressure of the pump, but not by bearing forces. Similar to the DE 01453760 or EP 0171514 constructed pumps, namely according to US 5 501 582 A . GB 2 263 312 A and DE 298 22 717 U1 , Although in addition to a direct radial bearing of the pump impeller also provide a plain bearing on the outside of the magnet rotor, but the radially inner bearing on the pump impeller leads to the known dry-running problems and a constraint of the pump impeller and high susceptibility to wear and unfavorable Gleichlaugeigenschaften the impeller magnetic rotor unit.

An important problem area in the operation of the previously presented magnetic pumps, which are thus provided with plain bearings and use the medium to be pumped itself as their cooling and lubricating medium, is the substantial or total absence just this liquid. Such lack of lubrication occurs when higher gas fractions accumulate in the liquid, for example by cavitation in front of the pump, Trombeneintrag or snoring. These gas components accumulate due to the centrifugal action in the pump in the radially inner cavities of the pump body. In the conventional construction It. FIGS. 1 to 3 and after US 5501582 A1 such as DE 298 22 717 U1 But exactly there are the sliding bearings, which then fall dry and are thus often destroyed. Therefore, many proposals have been made to address this problem. However, these solutions often remain the tribology of the friction partners arrested - coupled with the attempt to reduce the friction of the bearing in case of deficient lubrication and thus to avoid the thermal destruction.

A technically different and very sensible way, namely to move the endangered plain bearing radially as far as possible to the outside, is the solution of a "shaftless" magnetic pump as described in [4], which in FIG. 4 is shown. This construction is assigned to type A. It succeeds here to achieve a shaft and axle-less construction by a fixed portion (10 ') of the sliding bearing a portion of the gap pot (12') is used and the rotating part (9 ') of the sliding bearing by a portion of the protective jacket (8 ') is formed. The pump impeller (4 ') is connected to the magnet rotor (6'), the permanent magnet (7 ') and the protective jacket (8') to a hollow impeller magnetic rotor unit (19 ').

Nevertheless, the proposal from [4] remains technically limited. Thus, the radial slide bearing of the impeller magnetic rotor unit (19 ') takes place in the containment shell (12') itself, which, however, has to be executed at this point as a very thin-walled component. This is also pointed out in [4] and it is therefore not possible to dispense with more stable additional start-up or emergency bearings (37 ') which, disadvantageously, still partly have to be formed by the containment shell (12'). Furthermore, the support of the storage in thin-walled containment shell does not allow external cooling or easy external access, such as storage temperature monitoring or forced flushing.

It should be noted that in the event of a breakdown, e.g. cavitation in front of the pump, Trombeneintrag or snoring, a centrifugal pump is charged with significantly increased gas fractions in the liquid to be delivered. These gas components accumulate due to the centrifugal action in the pump in the radially inner cavities of the pump body. In conventionally designed magnetic drive pumps there are the sliding bearings, which then fall dry and are therefore often destroyed.

Based on this, the present invention seeks to improve the radial bearing in the magnetic coupling of a generic centrifugal pump. To solve this problem, a centrifugal pump with the features of claims 1 or 3 is proposed.

• die Lagerung der Laufrad-Magnetrotor-Einheit wird im Falle einer gaseintragenden Betriebsstörung außerhalb des gefährdeten Innenbereiches sicher weiterbetreiben, wobei auch das Abschleudern von Restflüssigkeit nach außen, die dann zur Lagerschmierung dient, günstig ausgenutzt wird;
• die Lagerung befindet sich nahe an der äußeren Gehäusewand, wo durch Kühlrippen die sich etwa erhitzende, nach außen abgeschleuderte Restflüssigkeit wirksam gekühlt werden kann;
• es wird eine vergleichsweise hohe Gleitgeschwindigkeit in den Lagern erzielt, so dass die Lagerung trotz der üblichen niedrigen Pumpendrehzahlen (in der Regel nur 1000 1/min bis 3000 1/min) auch bei niedrigen Fördermediumsviskositäten (oft wasserähnlich) in den Zustand der berührungsfreien Gleitung gelangen kann und damit das Mischreibungsgebiet herkömmlicher Gleitlagerungen in Magnetkupplungspumpen vermieden wird;

• es wird ein einfacher äußerer Zugang zu den Gleitlagern möglich und damit die Möglichkeit einer extern versorgten Lagerschmierung und/oder einer sensorischen Überwachung der Lager geschaffen;
• der Spalttopf findet nicht mehr als abstützendes Bauteil Verwendung, so dass er - sich der magnetischen Momentenübertragung unterordnend - stets dünnwandig ausgeführt werden kann und dennoch die Gefahr einer Überlastung und Deformation nicht besteht;
• des Weiteren werden Anlauf- und Notlager verzichtbar.

By means of the invention, which overcomes the imperfections of the prior art described in the introduction and in which the radial bearing of the impeller magnetic rotor unit is displaced outwardly as far as possible, the following advantages are achieved, inter alia:

• the bearing of the impeller magnetic rotor unit will continue to operate safely in the event of a gas-bearing malfunction outside the vulnerable interior, with the centrifuging of residual liquid to the outside, which then serves for bearing lubrication, is used to advantage;
• the storage is close to the outer housing wall, where by cooling fins, the approximately heated, thrown off to the outside residual liquid can be effectively cooled;
• a comparatively high sliding speed is achieved in the bearings, so that the bearings reach the state of non-contact sliding even at low pumped medium viscosities (often similar to water) despite the usual low pump speeds (generally only 1000 l / min to 3000 l / min) can and thus the mixed friction region of conventional sliding bearings in magnetic coupling pumps is avoided;

• it is a simple external access to the bearings possible and thus created the possibility of externally powered bearing lubrication and / or sensory monitoring of the bearings;
• the containment can no longer be used as a supporting component, so that it can always be made thin-walled, subordinating to the transmission of magnetic moments, and yet there is no danger of overloading and deformation;
• Furthermore, start-up and emergency camps are dispensable.

If the fixed part of the slide bearing is arranged on the inside wall surface of the pump housing as a whole or is formed independently by the housing wall or sections of the housing wall of the pump housing, high radial bearing forces can be transmitted over a large axial length and a smooth synchronization of the impeller magnet rotor Unit can be achieved. In the case of a plurality of axially spaced sliding bearing sections, these are preferably located approximately at the same radial level in order to further improve the running characteristics and the dry running capability of the bearing. Basically, it is within the meaning of the invention possible to store the pump impeller as such, in particular for receiving axial bearing forces. In addition, radial bearing forces can also be absorbed on the pump impeller, e.g. to achieve an improvement of runflat and / or starting properties. However, best synchronization conditions are achieved if the pump impeller can be rotated radially without contact or force.

If a liquid retention space is provided in the area of the sliding bearing of the impeller magnetic rotor unit, thereby the risk of dry running is reduced).

If the sliding bearing of the impeller magnetic rotor unit is carried out in its rotating part as a continuous sleeve, optionally in the form of a molding compound, thereby best possible material pairings and protection of the permanent magnets of the magnet rotor can be improved or simplified.

If the rotating part of the sliding bearing of the impeller magnetic rotor unit has recesses or elevations on its outer circumference, thereby the sliding properties improving liquid movements can be generated.

If the outside wall of the pump housing is provided in the region of the fixed part of the sliding bearing of the impeller magnetic rotor unit with cooling fins or a cooling jacket, overheating-related bearing damage can be avoided.

If accesses for external lubricants or monitoring sensors are provided in the wall of the pump housing in the region of the stationary part of the sliding bearing of the impeller magnetic rotor unit, lubrication or emergency lubrication or wear control of this slide bearing can be achieved.

If the pump housing wall has a multilayer structure and the innermost material layer consists of a corrosion- or abrasion-resistant material, the longevity is improved even with difficult pumped media.

The aforementioned embodiments of a centrifugal pump are independent of claim 1 of independent inventive importance.

If the magnet driver has at least one arranged in the region of the interior of the impeller magnetic rotor unit bearing, thereby the pump length can be significantly reduced despite independent storage of the magnetic driver within the pump. For the magnetic drive bearing bearings are preferably used. The rolling bearing of the magnetic driver remains unaffected by the pumped liquid. For this is preferably used a ansich known, arranged between the magnet rotor and the magnet driver split pot. The magnet driver preferably has an open towards the drive side cup shape to receive the at least one bearing of the magnet rotor within the pump housing. A particularly advantageous mounting of the magnetic driver is achieved by a hollow hollow cantilever, through which the drive shaft of the magnet driver is guided, and which preferably carries on at least one inner or outer surface at least one of its end portions a bearing for the magnetic driver. Tapering in these end areas facilitate the placement of such bearings in a small space. When the taper is made from the root of the cantilever, high bearing forces can be absorbed in a lightweight construction.

The at least partial storage of the magnetic driver within the space defined by the impeller magnetic rotor unit and the embodiments of such storage are of independent inventive significance.

The above-mentioned and the claimed components to be used according to the invention described in the exemplary embodiments are not subject to special conditions of size, shape, material selection and technical design, so that the selection criteria known in the field of application can be used without restriction.

Fig. 5

eine erste Ausführungsform einer erfindungsgemäßen Kreiselpumpe im Axialschnitt - schematisiert;

Fig. 6

eine zweite Ausführungsform;

Fig. 7

eine dritte Ausführungsform;

Fig. 8

eine vierte Ausführungsform;

Fig. 9

eine fünfte Ausführungsform;

Fig. 10

eine sechste Ausführungsform;

Fig. 11

eine siebte Ausführungsform;

Fig. 12

eine achte Ausführungsform;

Fig. 13

eine neunte Ausführungsform;

Fig. 14

eine zehnte Ausführungsform sowie

Fig. 15

eine elfte Ausführungsform.

Further details, features and advantages of the subject matter of the invention will become apparent from the subclaims and from the following description of the accompanying drawings, in which - by way of example - a preferred embodiment of the inventive arrangement of a centrifugal pump is shown with coaxial magnetic coupling. In the drawing show:

Fig. 5

a first embodiment of a centrifugal pump according to the invention in axial section - schematized;

Fig. 6

a second embodiment;

Fig. 7

a third embodiment;

Fig. 8

a fourth embodiment;

Fig. 9

a fifth embodiment;

Fig. 10

a sixth embodiment;

Fig. 11

a seventh embodiment;

Fig. 12

an eighth embodiment;

Fig. 13

a ninth embodiment;

Fig. 14

a tenth embodiment as well

Fig. 15

an eleventh embodiment.

The embodiments have in common that they have a suction nozzle 2 and a discharge nozzle 3 exhibiting pump housing 1, wherein a pump impeller 4 is mounted coaxially with the suction nozzle and is fluidly connected in the radial direction with the discharge nozzle 3. The pump impeller 4 has on the drive side a magnetic rotor 6, with which it forms an open to the drive side impeller magnetic rotor unit. This has on its outer circumference the rotating part 9 of a slide bearing, while the fixed part 10 of this sliding bearing is arranged on the inner wall 20 of the pump housing 1. On the radially inner side of the magnet rotor carries 6 permanent magnets 7. These are opposed to permanent magnets 14 with a radial distance, which are arranged on the outer surface of an approximately cup-shaped magnet driver Between the magnet rotor and the magnet driver is In all embodiments, a partition wall, possibly in the form of a so-called split pot 12, interposed, which keeps the magnetic driver dry against the liquid-wetted interior of the pump. The magnet driver 13 is supported at two axially spaced locations via rolling bearings 16a and 16b. This storage is in all embodiments - although not mandatory - each with respect to the pump housing 1 instead, said storage in the embodiments according to FIGS. 7 to 15 at least on the pump side takes place within the space formed by the impeller magnetic rotor unit 19. For this purpose, a continuous hollow Kragzapfen 39 from the drive-side housing end wall to the pump side down and has a tapered design 39a, 39b, wherein at its drive end portion which penetrates the drive shaft 15 of the pump is roller-mounted, while a second roller bearing in the opposite end on his Outside the drive shaft 15 indirectly, namely superimposed on the magnet driver 13. The latter has for this purpose on the drive side open cup shape.

The outer circumference of the impeller magnetic rotor unit 19 can now - with complete freedom of design and generous axial extent - be used to hold the rotating part 9 of the slide bearing ( FIG. 5 , upper half) and does not have to as in the prior art FIG. 4 be the most thin-walled protective jacket 8 for economic reasons. Again, this had led to the need for more radial startup and emergency bearings 37 in [4], which are no longer needed here in any way. It is even possible, with a suitable choice of the material and with appropriate shaping, that parts of the magnet rotor 6 itself can become the rotating part 9 of the sliding bearing ( FIG. 5 , bottom half).

Since all parts of the coaxial magnetic coupling are located radially further inward, the fixed part 10 of the plain bearing can readily be brought directly to the stable inner housing wall 20 of the pump housing 1 ( FIG. 5 , upper half) and no longer has to be disadvantageous the basically thin wall of the can 12, as described in [4]. It is even possible, with a suitable choice of the material and with appropriate shaping, that parts of the housing wall 20 of the pump housing 1 itself can become the stationary part of the sliding bearing 10 ( FIG. 5 , lower half), possibly only by a multi-layered design.

For an effective plain bearing it is irrelevant whether it is stored in two explicit bearing points 9, 10 a and 9, 10 b ( FIG. 5 , upper half), or whether the entire slide bearing is pulled apart into a single axially extended "bearing drum" ( FIG. 5 , bottom half). Also, combinations are conceivable, ie explicit rotating bearing 9a and b against fixed bearing 10 as an axially extended drum and vice versa.

An arrangement according to claim 1 not only offers significant technological advantages, but also leads to an extremely simple construction of the entire pump.

In the case of a - in practice frequent - malfunction of the pump over massive gas entry (air or evaporated fluid in consequence cavitation), the residual liquid remaining in the pump will accumulate as a thrown off ring on the outer circumference in the pump housing 1. In the case of a corresponding pump, the slide bearing 9, 10 is arranged exactly here, which can be operated as long as desired with the residual liquid with sufficient cooling. However, with very small residual amounts, which tend to occur at high delivery heights of the pump and low static counter-pressure, it can not be ruled out that these can escape axially in order to move to even higher radial levels in the impeller. This can be prevented via a lock in the form of a circulating ring 21, in FIG. 6 is shown. If the inner diameter of the Umlaufinges 21st chosen smaller than the contact diameter between the sliding bearing halves 9 and 10, the trapped and rotating liquid ring 23 will always wet the sliding bearing 9, 10 ( FIG. 6 , upper half). Another advantage of this design results in the stoppage of the pump, namely, when the circulation ring 21 prevents complete emptying of the pump in the region of the sliding bearing 9, 10. If the pump is then restarted, without a liquid is present at the suction nozzle 2, which is also a frequent operating error, then the slide bearing 9, 10 is still with the liquid in the liquid retaining space (22) remaining liquid template ( FIG. 6 , lower half) sufficiently lubricated and their axial escape during rotation also prevented by the lock.

The invention can also be exploited to significantly shorten the axial extent of the pump. This is possible by the magnetic driver 13 is not stored in the pump housing 1, but is placed directly on the shaft journal of the engine, so is ultimately stored by the prime mover. This is usually an electric motor. The electric motor is flanged directly to the pump, which is known as "block construction".
Advantage of this construction is in addition to the effect of axial shortening the savings of the two bearings 16. The disadvantage of this design is that the magnet driver 13 is no longer part of the pump and thus complete assembly of the pump can only be done if the driving motor present is. However, its size is initially at least in industrial pumps an unknown size and will be determined only on the basis of customer information. Thus, the time of final assembly of the pump is necessarily relocated behind this time and is also still an individual assembly with the known economic disadvantages.

Towards a better solution is in accordance with FIG. 7 initially a, preferably detachable, split pot 12 introduced, as it always finds use in industrial pumps. In practice, these splitters are made very thin-walled on the circumference in order to realize the smallest possible radial gap between the magnet rotor 6 and magnet driver 13 can. Due to the design For example, the containment shell 12 can be designed with a smooth end wall and must point with its larger opening in the direction of the drive side. Although the split pot 12 itself should not be used to support a rolling bearing because of its thinness, but now offers according FIG. 7 In this way, the axial Baumass the pump can be shortened to that of the conventional block design, but here the magnet driver 13 remains part of the pump, resulting in a complete series assembly and stockpiling of the pump allowed.

The shaft end 25 in such an axially shortened construction can advantageously according to FIG. 8 be carried out so that either via a conventional pump clutch (shown only the pin portion 27 of the pump clutch) the direct connection of a motor is possible (which could be flanged via an intermediate ring also directly to the pump) or a shaft journal 28 again with the conventional pump free shaft end leads (eg to comply with specified standard dimensions). Also, such a shaft end 25 should provide the opportunity to attach an additional flywheel 26 to compensate for the mentioned disadvantage of the type B chosen here when starting the pump can. All this would be part of the final assembly of the pump unit (which would also be carried out by the user of the pump itself) and would still allow a large-scale series assembly and cheap stockpiling of the pump at the manufacturer as described above.

The rotating part 9 of the plain bearing need not necessarily consist of two defined bearing sleeves a and b or from the magnet rotor 6 itself, but can FIG. 9 also as an axially continuous sleeve 29 (FIG. FIG. 9 , upper half) or molding compound 30 ( FIG. 9 , lower half).

This offers economic advantages, especially if these components according to FIG. 10 also to protect and seal the radially lower Magnet rotor 6 and the permanent magnets 7 serve. Namely, it is quite common, depending on the field of application of the pump, that the magnet rotor 6 as ferromagnetic carrier of the permanent magnets 7 must be protected from the attack of the liquid to be conveyed and not as the pump impeller (4) may come into contact with the liquid , The now assumed difference in the materials between pump impeller 4 and magnet rotor 6 is expressed in a different hatching

The desired completely contact-free and thus wear-free and low-friction sliding of the impeller magnetic rotor system 19 in the pump housing 1 is opposed by the high peripheral speed of this arrangement. By additional dimple-like recesses or elevations on the surface of the rotating plain bearing 9, for example on the sleeve 29 or the molding compound 30, so-called Taylor vortices can be generated in the sliding gap and in the adjacent rotational space of the liquid, which contribute to the stabilization and to the contactlessness of the sliding bearing , These recesses or elevations are with FIG. 11 introduced.

In particular, if in the case of a malfunction in the pump only a liquid ring 23 rotates and a stream of fresh lubricant fails, this residual liquid will heat up in the plain bearing due to friction until a heat transfer equilibrium with the pump housing 1 is reached. Due to the direct contact of the slide bearing 9, 10 with the pump housing 1 is here by attachment of outer cooling fins 32, as in FIG. 12 be introduced, a directly effective way of increased convective heat dissipation and thus the reduction of the stationary temperature of the liquid ring 23 at a prolonged malfunction. In the upper half of FIG. 12 is a Querverrippung shown in the lower longitudinal ribbing. This latter should be more useful in practice, since this can be used to advantage the already existing cooling air flow of the driving electric motor, which always takes place in the direction of the pump.

In order to prevent the lack of lubrication of the sliding bearing 9, 10 even in the case of a corresponding malfunction, the supply of external lubricating fluid is loud FIG. 13 and / or a sensory monitoring (eg temperature, vibration, structure-borne noise) of the sliding bearing 9, 10 loud FIG. 14 proposed. Here, the proximity of the slide bearing 9, 10 to the pump housing 1 acts so that this access can be done very easily.

Many running magnetic drive pumps, which are particularly suitable for promoting aggressive, abrasive and hazardous liquids due to the hermetic seal of the pump interior are lined in the wetted area of the pump housing 1 with about a plastic layer or from several - usually two - constructed material shells. Ultimately, then the innermost layer of material 35 must have the desired properties with respect to the liquid, while the outer shells serve more the shape and stability to the internal pressure of the pump. FIG. 15 makes this construction also for the present invention. Since in particular the mentioned plastic materials (eg PTFE or PE) can be used very well as a sliding bearing material in mixed friction area, a construction is proposed, as they FIG. 15 in the lower half shows. If, on the other hand, the material of the innermost material layer 35 is not suitable for plain bearings, the construction in the upper half of FIG FIG. 15 recourse.

LIST OF REFERENCE NUMBERS

1

pump housing

2

suction

3

pressure port

4

Impeller

5

impeller shaft

6

magnet rotor

7

Permanent magnet (rotor)

8th

mantle

9

rotating plain bearing

9a

rotating plain bearing, impeller side

9b

rotating plain bearing, drive side

10

fixed plain bearing

10a

Fixed plain bearing, impeller side

10b

Fixed slide bearing, drive side

11

bearing insert

12

containment shell

13

magnetic driver

14

Permanent magnet (driver)

15

drive shaft

16a

Rolling bearing, impeller side

16a

Rolling bearing, drive side

17

axis

18

flow ribs

19

Impeller-magnetic rotor unit

20

Inside wall of the pump housing

21

circumferential ring

22

Fluid retention area

23

rotating amount of residual fluid

24

Interior of the containment shell

25

shaft end

26

Inertia

27

Spigot part of a pump coupling

28

shaft journal

29

shell

30

molding compound

31

recesses

32

cooling fins

33

Access for lubricating fluid

34

Access for sensors

35

Innermost material layer

36

sealant

37

Approach or emergency camp

38

Outer circumference of the impeller magnetic rotor system

39

collar journal

39a

rejuvenation

39b

rejuvenation

LITERATURE

1. [1] Brochure of
   Company WERNERT-PUMPEN GMBH
   
   D-45476 Mülheim an der Ruhr Standardized chemical plastic pump with magnetic coupling - Type series NM Edition 687/02
2. [2] Brochure of
   Company IWAKI pumps
   Iwaki Magnetic Pumps - MDM Series
   printed in Japan 99.11.ITN
3. [3] Brochure of
   Company CP-Pumpen AG CH-4800 Zofingen:
   Magnetic coupling pump MKP, metallic
4. [4] Robert Neumaier: Hermetic pumps Verlag und Bildarchiv WH Faragallah, 1994 ISBN-3-929682-05-2 Chapter 3.7.12 Wave-less magnetic-coupling centrifugal pumps p. 356 ff

Claims (21)

1. Rotary pump

   - comprising a static and enclosed containment of the pumped liquid in the interior of the pump in the form of a housing (1),

   - with a contact-free permanent magnet coaxial rotary coupling (6, 7; 13, 14) for transferring a drive moment into the interior of the pump housing

   - with a pump impeller (4) which forms, together with a magnetic rotor (6) which carries permanent magnets (7), a pot-shaped component (impeller-magnetic rotor unit 19) which is mounted on sliding bearings and is open toward the drive side,

   - and wherein the magnetic force lines of the driving part of the rotary coupling (magnetic driver 13 and permanent magnets 14) face radially outwardly and the magnetic force lines of the part of the rotary coupling (magnetic rotor 6 and permanent magnets 7) connected to the pump impeller (4) face radially inwardly,

   characterised in that, for radial mounting of the impeller-magnetic rotor unit (19)

   - the rotating part (9; 9a, 9b) of a sliding bearing mounting is altogether arranged along the outer periphery (38) of the magnetic rotor (6) and is firmly connected thereto or is formed by the outer periphery or sections of the outer periphery (38) of the magnetic rotor (6).
2. Rotary pump according to claim 1, characterised in that the fixed part (10; 10a, 10b) of the sliding bearing mounting is arranged on the internal wall surface (20) of the pump housing (1) or is provided by the housing wall or sections of the housing wall (20) of the pump housing (1).
3. Rotary pump according to claim 1 or 2, wherein a plurality of axially spaced sliding bearing sections (9a, 10a; 9b, 10b) is provided which are arranged at approximately the same radial level.
4. Rotary pump according to one of the claims 1 to 3, characterised in that the pump impeller (4) can rotate without radial contact or constraint.
5. Rotary pump according to one of the claims 1 to 4, characterised in that arranged between the pump impeller (4) and the sliding bearing mounting (9, 10) is a peripheral ring (21) or collar such that the inner dimension thereof is smaller than the contact diameter of the sliding bearing mounting (9, 10) and thereby a fluid retention chamber (22) is obtained in the region of the sliding bearing mounting (9, 10) both on rotation and on standstill of the pump impeller (4).
6. Rotary pump according to one of the claims 1 to 5, characterised in that the rotating part (9; 9a, 9b) of the sliding bearing mounting is configured as an axially continuous sleeve (29) or an axially continuous cast or pressed moulding mass (30).
7. Rotary pump according to claim 6, characterised in that the sleeve (29) or the moulding mass (30) have been or are applied, formed or sealed with sealing means (36) such that said sleeve or moulding mass become part of a protective jacket (8) for the permanent magnet (7) and/or the magnetic rotor (6).
8. Rotary pump according to one of the claims 1 to 7, characterised in that the rotating part (9; 9a, 9b) of the sliding bearing mounting is provided on the outer periphery of said rotating part with a plurality of local recesses (31) or elevations which favour the formation of stabilising flow eddies in the sliding bearing mounting.
9. Rotary pump according to one of the claims 1 to 8, characterised in that the external wall of the pump housing (1) is provided in the region of the fixed part (10) of the sliding bearing mounting with cooling ribs (32).
10. Rotary pump according to one of the claims 1 to 9, characterised in that the fixed part (10) of the sliding bearing mounting can be supplied through one or more accessways (33) in the wall of the pump housing (1) with external lubricant.
11. Rotary pump according to one of the claims 1 to 10, characterised in that the fixed part (10) of the sliding bearing mounting can be monitored through one or more accessways (34) by sensors in the wall of the pump housing (1).
12. Rotary pump according to one of the claims 1 to 11, characterised in that the wall of the pump housing (1) is made from a plurality of material layers and the innermost material layer (35) is made from a corrosion-proof and/or abrasion-proof material.
13. Rotary pump according to one of the claims 1 to 12, wherein arranged between the magnetic rotor (6) and the magnetic driver (13) is a separating wall which faces, with the opening thereof, the drive side of the pump and separates the fluid in the interior of the pump from the magnetic driver (13), characterised in that

    - the magnetic driver (13) is mounted in at least one bearing connected to the pump, for example, a roller bearing (16),

    - at least one impeller-side bearing, for example, a roller bearing (16a) is situated in the inner region (24) of the pump housing and

    - the magnetic driver (13) is mounted without contact with the separating wall.
14. Rotary pump according to claim 13, characterised in that the at least one impeller-side bearing is situated in the internal region of a magnetic driver (13) which is hollow internally.
15. Rotary pump according to claim 13 or 14, characterised in that the internal ring is fixed by the impeller-side bearing and the associated external ring rotates with the bearing mounted magnetic driver (13).
16. Rotary pump according to claim 15, characterised in that a drive-side bearing, for example, a roller bearing (16b) is provided, the internal ring of which rotates with the bearing mounted drive shaft (15) and is fixed to the associated external ring.
17. Rotary pump according to one of the claims 13 to 16, characterised in that a continuous hollow protruding journal (39) is provided extending inwardly from the drive side into the pump housing (1) in order to receive the drive shaft (15) and is or can be connected to the pump housing.
18. Rotary pump according to claim 17, characterised in that the hollow protruding journal (39) has at least one narrowing (39a; 39b) at one of the end regions thereof.
19. Rotary pump according to one of the claims 13 to 18, characterised in that the region of the drive-side end (25) of the drive shaft (15) is configured to comprise an inertial mass (26) or is provided therewith.
20. Rotary pump according to one of the claims 13 to 19, characterised in that the region of the drive-side end (25) of the drive shaft (15) is configured so that said region can optionally be detachably coupled to an inertial mass (26), a journal part (27) of a pump coupling and/or to a shaft journal (28).
21. Rotary pump according to one of the claims 13 to 20, characterised in that the magnetic driver (13) comprises a pot form which is open toward the drive side.

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