EP2870362A1

EP2870362A1 - Double-walled split case of a magnet coupling, in particular of a magnet coupling pump

Info

Publication number: EP2870362A1
Application number: EP13753527.4A
Authority: EP
Inventors: Günther Schneider; Michael Westib; Christian JUSSEN; Katja WISCHMANN
Original assignee: Ruhrpumpen GmbH
Current assignee: Ruhrpumpen GmbH
Priority date: 2012-07-06
Filing date: 2013-06-25
Publication date: 2015-05-13
Also published as: CN104411978A; DE202012006480U1; CN104411978B; US9617999B2; DE112013003463A5; US20150206637A1; WO2014005564A1

Abstract

The invention relates to a magnet coupling, in particular magnet coupling pump, which has an inner rotor and an outer rotor, each of which bear magnets between which there is arranged a double-walled split case (6) which has an outer case (7) and an inner case (8) which each have a flange (17, 18), a central section (11, 12) and a base section (13, 14), wherein a gap (16) is arranged between the central section (11, 12) and the base section (13, 14), and wherein the inner case (8) is connected by way of its flange (17) to the flange (18) of the outer case (7). It is proposed that the gap (16) be filled at least in regions with a solid material (19).

Description

Double-walled containment shell of a magnetic coupling, in particular a magnetic coupling pump

The invention relates to a magnetic coupling, in particular a magnetic coupling pump having an inner rotor and an outer rotor, each carrying magnets between which a double-walled containment shell is arranged, which has an outer pot and an inner pot, each having a flange, a central portion and a bottom portion, wherein between the central portion and the bottom portion, a gap is arranged, and wherein the inner pot is connected via its flange with the flange of the outer pot.

Magnetic clutch pumps are well known, and described for example in DE 10 2009 022 916 A1. In this case, the pump power is transmitted from a drive shaft via a magnet-bearing rotor (outer rotor) without contact and essentially without slippage to the pump-side magnet carrier (inner rotor). The inner rotor drives the pump shaft, which is mounted in a slide bearing lubricated by the fluid, so in a hydrodynamic sliding bearing. Between the outer rotor and the inner rotor, so between the outer and the inner magnet is the containment shell with its cylindrical wall. The containment shell is connected at its flange to a pump component, for example a housing cover, and has a closed bottom opposite thereto. The containment shell, so the magnetic coupling pump reliably separates the product space from the environment, so that the risk of product leakage could be excluded with all the associated negative consequences. A magnetic coupling pump is therefore the combination of a conventional pump hydraulics with a magnetic drive system. This system uses the attraction and repulsion forces between magnets in both coupling halves for non-contact and slipless torque transmission. Between the two rotors equipped with magnets is the containment shell, which separates the product space and the environment from each other. Especially when dealing with very valuable or very dangerous substances, the magnetic coupling pump therefore has great advantages.

Canned pots may be made of different materials such as e.g. consist of metals of various alloy compositions, plastic or ceramic. Metal containment shells disadvantageously cause eddy current losses, with plastic gap pots having limited temperature and / or pressure resistance.

| Bestätigungskopiel dig, which is disadvantageous especially at high medium temperatures and / or high pump pressures. In this respect, ceramic gap pots have gained acceptance in practice, and lately glass cans (DE 10 2009 022 916 A1) have become known.

Centrifugal pumps with magnetic coupling or magnetic coupling pumps according to DIN EN ISO 2858 and DIN EN ISO 15783 and API 685 are thus equipped in the standard known manner with single-walled slotted pots. The containment shell separates the product space from the atmosphere without leakage and forms the static seal between the inner and outer magnet rotor. Usually, the containment shell has a wall thickness of 1-2 mm in the cylindrical part, ie in its middle section. Damage to the containment shell as a result of rolling bearing damage to the outer magnet rotor or sliding bearing damage in the region of the inner magnet rotor can lead to the discharge of delivery fluid into the atmosphere space of the intermediate lantern. In order to avoid leakage of pumped liquid u. a. when pumping hazardous (eg toxic, carcinogenic, aggressive) conveying fluids, double-walled containment shells are used.

Double-walled containment pans are e.g. from EP 0 286 822 B1 but also from EP 0268 015. From EP 1 777 414 A1, a double-walled containment shell is known whose inner pot and outer pot contact each other at least in the area of the cylindrical jacket surface, wherein in this contact zone a network of paths is formed, in which a liquid medium, ie a medium of sufficient viscosity, such as e.g. Liquids or pasty masses, for example, a thermally conductive oil is arranged.

When using single-walled cans magnetic power losses of 10-15% are accepted. This value can double when using double-walled containment pans. Due to the system, the magnetic power losses in the case of metal cans are converted into heat, which is dissipated via the product. Due to the design, however, the heat generated at the outer containment shell can not be completely released to the atmosphere. It is important here to dissipate the heat between the outer and inner split pot as a result of the air-filled or evacuated gap on thermally conductive products in the product. Known here is the use of heat transfer oils or thermally conductive paste. The main disadvantage is to be considered that z. B. damage to the outer containment shell with a corresponding outlet of wärmeleitfä- higen liquids or pastes from the gap of the gap pots in the atmosphere with the risk of ignition, or damage to the inner containment shell by incompatibility of the thermally conductive liquid or paste with the product, so that it is useless due to contamination. However, it is also disadvantageous that special sealing measures have to be taken in particular in the area of the contiguous flanges of the outer and inner pot, so that an escape of the liquid or paste introduced into the gap is avoided even if the double-walled containment shell is intact. Additional sealing measures, however, mean additional effort and additional use of materials. In addition, the special seal still contains additional risk potential, since the sealing measure can fail, so that a standstill must be feared, although the inner pot and the outer pot are actually still intact. Particularly in the case of a revision in which the double-walled containment shell may also be dismantled for Kotrollzwecken, a considerable effort must be made that the liquid present does not enter the environment.

The invention has for its object to provide a magnetic coupling, in particular a magnetic coupling pump of the type mentioned above available, in which simple means an improved containment shell in doppelwandiger design avoids at least the above-mentioned disadvantages.

According to the invention the object is achieved by a magnetic coupling, in particular with a magnetic coupling pump with the features of claim 1.

It should be noted that the features listed individually in the claims can be combined with each other in any technically meaningful way and show other embodiments of the invention. The description additionally characterizes and specifies the invention, in particular in connection with the figures.

According to the invention, a magnetic coupling, in particular a magnetic coupling pump is proposed, which has an inner rotor and an outer rotor, each carrying magnets between which a double-walled containment shell is arranged, which has an outer pot and an inner pot, each having a flange, a Central portion and a bottom portion, wherein between the central portion and the bottom portion, a gap is arranged, and wherein the inner pot is connected via its flange with the flange of the outer pot. It is advantageously provided that the gap is at least partially filled with a solid material.

Characterized in that the gap is at least partially filled with a solid material, there is no longer the risk that this mixes in a defective either the inner pot with the Fördemedium in a harmful manner, or passes in an outer pot defect to the atmosphere. Although there is the possibility of a respective defective outer or inner pot, however, the solid material remains in its position and does not dissolve. It is also beneficial that can be dispensed with each other to Abdichtmaßnahmen on the flange of the two pots, since the solid material property due to not tending to leave its position, for example, to flow out or exit, as is possible with liquids or pastes. For in the case of solids, or in the case of the solid material according to the invention, the viscosity is very high (ie difficult to determine), which means for the purposes of the invention that the solid material is by no means free-flowing when the solid material is arranged in the gap.

Targeting is when the solid material is a thermally conductive material. It is favorable if the solid material is a thermally conductive plastic. Appropriately, the solid material may be a silicone, or a thermally conductive silicone sheath. It is possible that the solid material is a thermally conductive foil.

The solid material may be arranged only in a certain area in the gap, that is, in a region of the gap between the central portions and / or between the bottom portions. Thus, the solid material may e.g. along the gap also be interrupted in this arranged. In a further expedient embodiment, the solid material fills the entire gap between the opposite central portions or bottom portions of the inner pot and the outer pot throughout. In a further preferred embodiment, it may be provided to arrange the solid material throughout the gap between the middle sections and the bottom sections.

In an advantageous embodiment, the solid material fills the gap in the axial direction along the gap seen at least partially, wherein the solid material completely fills the gap in this area seen in the radial direction. In this respect, the solid material is virtually a bridge between the inner circumference of the outer pot and the outer circumference of the inner pot. The term "along the gap in the axial direction" in the context of the invention includes both the gap between the center sections and between the preferably curved bottom sections, wherein the term "radial direction" in the meaning of the invention to the gap between the inner diameter of the outer pot and the Outer diameter of the inner pot and that relates to both the central portion and the preferred curved bottom portion.

Targeting within the meaning of the invention is when the solid material is connected to the inner pot or at least rests on the outer circumference, which refers to a pre-assembly. In the assembled state, the solid material is at least partially, as explained above, both with the inner circumference of the outer pot and with the outer circumference of the inner pot in connection. For connecting the solid material to the inner pot it can be provided that the solid material is shrunk onto the inner pot in the manner of a shrink tube. For an assembly of the inner pot in the outer pot expedient manner is provided that the outer pot initially has a larger inner diameter than necessary, which is achieved by means of heating. If the outer pot subsequently cools down, the inner diameter, which is necessary due to the design, has an inner diameter that is necessary for its construction, and is connected to it at least in regions, interrupted or completely connected to the solid material.

Since solid material is arranged according to the invention in the gap, the flange connection between the inner pot and the outer pot requires no additional sealing measures. In this respect, the flange can have, for example, a screw without regard to any leaking liquid media, of course, optionally a seal, for example, can be provided as an O-ring seal. Since, for example, it is possible to dispense with a welded joint or a temperate-adhesive bond, there are many possibilities with regard to the material to be selected from the outer pot and the inner pot, since materials of the same type can also be selected. For example, the inner pot can be formed from a nickel-based alloy, for example from a Hastelloy®, wherein the outer pot can be formed from a titanium alloy. In particular, when the outer pot is formed of a titanium alloy, there are many advantages, since this material has a high electrical resistance, high strength and good thermal conductivity, which results in a significant reduction of the total magnetic power loss, which is advantageous to the Energieef- efficiency of the magnetic coupling pump. Also, the wall thickness of the outer pot can be reduced in the central portion due to the properties of the titanium alloy and, for example, have an amount of 0.5 mm, which then results in a further reduction of the magnetic power loss. The mentioned amount is of course only exemplary and by no means limiting.

The solid material is designed as a separate material to the two pots, however, with preferably two pots each standing in conjunction and has a dual function. On the one hand, the solid material has a stability effect of the two split pots, which are advantageously spaced apart from each other in the respective middle section and bottom section. On the other hand, the solid material assumes the function of heat transfer from the outer pot in the pumped medium.

With the invention, a double-walled containment shell is made available, the outer pot and inner pot are individually independently interchangeable, since only the flange screw must be solved. So if only one of the two pots is defective, only this must be replaced, which is particularly beneficial especially in the used, high-priced pot materials. In addition, the inner pot and the outer pot have no contact zones either in the middle section or in the bottom section. Rather, the outer pot and the inner pot along the gap in the middle and bottom portion in the axial direction are kept completely non-contact, with a also be introduced in the inner periphery of the outer pot route network deleted.

Further advantageous embodiments of the invention are disclosed in the subclaims and the following description of the figures. Show it:

1 shows a magnetic coupling pump in a sectional view, and

Fig. 2 shows a double-walled containment shell of a magnetic drive pump in a sectional view.

In the different figures, the same parts are always provided with the same reference numerals, which is why they are usually described only once. Figure 1 shows a magnetic coupling pump 1 which has an inner rotor and an outer rotor, each carrying magnets, and with a pump shaft 2, for example as a stainless steel shaft 2, which carries an impeller 3, and which is mounted in a hydrodynamic sliding bearing 4, wherein the hydrodynamic sliding bearing 4 can be externally lubricated by the conveying medium, but also with another, product-compatible fluid. The magnetic coupling pump 1 is known per se, which is why it is not described in detail.

2 shows a split pot 6 of the magnetic coupling pump 1 of Figure 1, wherein the containment shell 6 is designed as a double-walled containment shell 6 having an outer pot 7 and an inner pot 8, each having a flange 17 and 18, a central portion 11, 12 and a bottom portion 13, 14, wherein between the respective central portion 11, 12 and the respective bottom portion 13, 14, a gap 16 is arranged. The inner pot 8 is connected via its flange 17 to the flange 18 of the outer pot 7. It is advantageously provided that the gap 16 is at least partially filled with a solid material 19. The solid material 19 is indicated in Figure 2 as a solid line.

The respective central portion 11, 12 is seen in section, each cylindrical, wherein each of the respective central portion 11, 12 adjoining bottom portion 13,14 is curved. Both vaults are equally oriented.

As exemplified, the gap 16 is continuously and completely filled both in the axial direction and in the radial direction with the solid material 19. Only in a pocket 21, which in each case is due to production between a transition region of the bottom portion 14 of the outer pot 7 to the central portion 12 is present, no solid material is arranged.

For connecting the two flanges 17 and 18, a screw connection, not shown, is provided. Since solid material 19 is arranged according to the invention in the gap 16, the flange connection between the inner pot 8 and the outer pot 7 does not require any additional sealing measures, wherein in FIG. 2 an optional seal 9 is arranged, for example in the embodiment as an O-ring seal 9. The solid material 19 is arranged and designed so that both the inner periphery 22 of the outer pot 7 and the outer periphery 23 of the inner pot 8 are in communication with the solid material 19.

As can be seen in Figure 2, both the respective central portion 11, 12 and the respective bottom portion 13,14 held completely free of contact. Only the flanges 17 and 18 are in mutual contact.

Figure 2 also shows a test port 24 with corresponding test device 25, which is arranged in the flange 18 of the outer pot 7, so that a defective inner pot 8 and / or outer pot 7 can be detected, with a defective inner or outer pot a mass pressure change of the solid material 19 is receivable.

The solid material 19 in the gap 16 is in the introduced in the gap 16 and this filling state an absolutely flow-incompatible material, wherein the solid material is preferably a solid plastic or a silicone.

The solid material 19 can be shrunk onto the outer circumference 23 of the inner pot 8, for example, in the manner of a heat-shrinkable tube. It is also possible to introduce as a solid material silicone in the mounted double-walled containment shell 6, which is flowable only for filling purposes, but then solidified to an absolutely flow-resistant permanently elastic mass.

LIST OF REFERENCE NUMBERS

1 magnetic drive pump

2 stainless steel shaft

3 impeller

4 plain bearings

5

6 Double-walled containment shell

7 outer pot

8 inner pot

9 seal

10

11 middle section of 8

12 middle section of 7

13 floor section of 8

14 floor section of 7 15

16 gap

17 flange of 8

18 flange of 7

19 Solid material

20

21 bag

22 inner circumference of 7

23 outer circumference of 8

24 test connection

25 test device

Claims

claims

1. Magnetic coupling, in particular magnetic coupling pump, which has an inner rotor and an outer rotor, each carrying magnets between which a double-walled containment shell (6) is arranged, which has an outer pot (7) and an inner pot (8), each having a flange ( 17,18), a central portion (1 1, 12) and a bottom portion (13,14), wherein between the central portion (1 1, 12) and the bottom portion (13,14), a gap (16) is arranged, and wherein the inner pot (8) via its flange (17) with the flange (18) of the outer pot (7) is connected, characterized in that the gap (16) at least partially filled with a solid material (19).

2. Magnetic coupling according to claim 1, characterized in that the solid material (19) is a thermally conductive material (19).

3. Magnetic coupling according to claim 1 or 2, characterized in that the solid material (19) is a thermally conductive plastic (19).

4. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) is a thermally conductive silicone (19).

5. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) is a thermally conductive foil (19).

6. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) at least partially in the gap (16) between the central portion (1 1) of the inner pot (8) and the central portion (12) of the outer pot (7) is arranged.

7. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) at least partially in the gap (16) between the bottom portion (13) of the inner pot (8) and the bottom portion (14) of the outer pot (7) is.

8. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) is disposed continuously in the gap (16) between the central portion (11) of the inner pot (8) and the central portion (12) of the outer pot (7) ,

9. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) is disposed continuously in the gap (16) between the bottom portion (13) of the inner pot (8) and the bottom portion (14) of the outer pot (7) ,

10. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) is arranged throughout in the entire gap (16).

1 1. Magnetic coupling according to one of the preceding claims, characterized in that the solid material (19) with the outer periphery (23) of the inner pot (8) but also with the inner periphery (22) of the outer pot (7) is in communication.

12. Magnetic coupling according to one of the preceding claims, characterized in that the inner pot (8) consists of a nickel-based alloy, wherein the outer pot (7) is formed from a titanium alloy.