DE10240800A1 - Pump with non-metal surface in contact with feed medium circuit for fluid feed medium provided between feed chamber and clearance gap by means of first passage lying outside shaft and second passage lying inside shaft - Google Patents

Abstract

The pump (40) with a non-metal surface in contact with a feed medium has a shaft (47) with a feed rotor (54) for the feed of a fluid medium (56) in a feed chamber (57), and a drive rotor (45) to drive the feed rotor, with a magnetic coupling in between the two rotors acting inside a clearance gap (48). A circuit for the fluid feed medium is provided between the feed chamber and clearance gap by means of a first passage lying outside the shaft, and a second passage lying inside the shaft, whereby the second passage runs outside the center of the shaft. An Independent claim is included for a procedure for the provision of a fluid feed circuit in a pump.

Description

The invention relates to a pump with one to a pumped medium bordering non-metallic surface, comprising a shaft that is a subsidy on a conveyor-side piece to promote a liquid conveying medium in a funding room has and on a drive-side piece a conveyor rotor for driving the conveyor having a magnetic coupling by means of a magnetic coupling of the conveyor rotor and a drive rotor over one between the conveyor rotor and drive rotor extending gap space is effected. The invention further relates to a method for providing a circuit a medium in the case of a pump with a non-metallic one bordering on a pumped medium Area, which pump has a shaft that has a conveyor on a conveyor-side piece has by means of a liquid conveying medium in a funding room promoted is and has a conveyor rotor on a drive-side piece, by means of which the funding is driven, using a magnetic coupling a magnetic Coupling the conveyor rotor and a drive rotor over one between conveyor rotor and drive rotor extending gap space is effected.

Magnetic clutch pumps of the above Kind usually show pump hydraulics designed according to requirements, plain bearings the shaft and a magnetic coupling unit. Usually generate permanent magnets with changing polarity in the circumferential direction across the gap away a magnetic field, the attraction of which is sheared by a Receives circumferential component and so transmits a torque between the drive rotor and conveyor rotor. Consequently is the funding through the Shaft rotated when the pump is operating. Usually the wave stored in plain bearings. These are normally caused by the pumped liquid rinsed. The rotating magnetic field also induces, especially in the case of metallic ones Share eddy currents. About the heat it creates dissipate and to lubricate the bearings becomes part of the flow the pump branched and passed through the drive unit. meaningful is a forced flow the bearings and the gap. Otherwise, namely when the substream is separated in a separate cooling and lubrication flow the division can be dependent on many boundary conditions, so that it Give operating states could, not the lubricating flow or the cooling of the gap would ensure sufficiently. The partial flow, which is the forced flow through the bearings and the gap should effect and referred to in the following as a "cycle" is the flow rate fed back to the pump at a suitable point. there the cavitation behavior of the pump must be observed. Warming the circuit as well as the disorder the mainstream of the medium in the funding area have a negative impact. Furthermore, there are a number of Difficulties in providing the circuit mentioned for the medium between funding room and gap space, depending on the construction and design of a magnetic coupling pump. Solids pose a significant problem in the funding guided are and easily with intermediate design of the circuit the bearings and in the gap.

A first design of magnetic coupling pumps essentially provides for metallic parts and, accordingly, also for metallic open areas bordering on the conveying medium. Such a magnetic coupling pump made of metal according to the prior art is for further illustration in 1 shown. The circuit for the conveying medium between the conveying space and the gap space is provided in such a magnetic coupling pump made of metal, in particular by means of a hollow pump shaft, via which the partial flow of the conveying medium in the circuit is returned to the main flow of the conveying medium in the conveying space. This allows sufficient cooling and / or lubrication of the slide bearings for the shaft and the parts located in the vicinity of the magnetic coupling. Metal pumps thus basically have an advantageous coolant circulation, but on the other hand, a very large amount of heat is generated in a metal pump by eddy current losses in metal parts. A correspondingly extensive circuit must therefore be provided for a partial flow of the conveying medium in order to dissipate this amount of heat. In particular, a large amount of the partial flow has to be directed through boreholes, partly in a targeted manner into the gap space or adjacent rooms, so that the amount of heat can be dissipated sufficiently.

This has significant disadvantages because Pumps of the type mentioned above, in some cases with considerable amounts of solids loaded media have to promote. Such solids can easily clog the circuit in metal pumps, especially there the circuit is extensively dimensioned due to the amount of heat generated and over the holes mentioned should be filigree. Lubrication and / or cooling the bearing and / or the magnetic coupling could fail, at worst for destruction of the pump. Become conveyed with a magnetic pump solids-laden media therefore an externally supplied coolant and lubricant is usually required.

In addition, magnetic coupling pumps are generally intended to pump chemically aggressive fluids. Magnetic coupling pumps made of metal are only poorly suited for the conveyance of such media, since the metallic open surfaces bordering on the conveyed medium are not sufficiently corrosion-resistant. A plastic insulation of a hollow shaft at ei A metal pump would be theoretically possible, but is technically unrealistic. Metallic open areas would normally have to be insulated against aggressive liquid media with a layer of at least 3 to 4 mm plastic. This leads to intolerable disadvantages in the design, manufacture and operation of the pump.

According to the prior art, magnetic pumps made of plastic are therefore provided. Such a pump according to the prior art is shown in FIG 2 shown. Such a pump has non-metallic surfaces bordering the pumped medium. In particular, the impeller, pump rotor and shaft of such a plastic pump are made of metal in the core, but are plastic-coated. In the case of a plastic pump, a hollow shaft is structurally and technically disadvantageous. It would not be possible to transmit a sufficiently large torque. In the case of plastic pumps, the conveying means is attached to the shaft by means of central screwing on the shaft, which is another obstacle for a shaft. On the other hand, a solid shaft is provided in plastic pumps to ensure a sufficiently large torque transfer. A hollow shaft would theoretically be possible with a plastic pump. However, an external thread for an impeller would have to be attached, which would not be independent of the direction of rotation. Furthermore, the metallic components (impeller / pump shaft / bore of the pump shaft) would have to be sealed.

Because of a missing hollow shaft So far no targeted guidance of the plastic pumps conveying medium provided in a further circuit between the production area and the gap area become. This usually means no or insufficient fluid exchange in the part of the pump on the drive side. A plastic pump is according to the state not susceptible to technology across from chemically aggressive fluids, however, it is due to the lack of circulation for the fluid between funding room and gap space very vulnerable across from Blockages in the fluid supply to the part of the pump on the drive side.

A from the prior art according to the EP 0 664 400 B1 A known attempt to solve the problem is a plastic pump which has a hollow shaft made of ceramic. Such a pump is shown in FIG 3 shown. Although such a pump may ensure an adequate circulation of the pumped medium, it can only transmit limited torques via the ceramic hollow shaft. Torque is not only limited due to the hollow shaft itself, but is even more limited by the fact that a ceramic inherently has a certain brittleness, so that a ceramic shaft cannot be loaded like a metal shaft.

According to the US 5,641,275 and the US 5,997,264 a magnetic clutch pump is generally described. Features of a plastic pump are not disclosed there. The magnetic coupling pump described therein has a stationary, standing axis, which is preferably made of a ceramic and has a number of notches or grooves on the surface. The notch or groove in the above-mentioned US applications is located on the surface of the stationary axis in the area of the bearing of the axis and can cause considerable problems. A stationary axis in plastic pumps is also associated with certain disadvantages. The groove or notch provided in the above-mentioned US applications primarily serves to discharge solids contained in the funding, which can accumulate particularly easily in the containment chamber space in the funding cycle proposed in the US applications. According to the in 12 the US 5,641,275 funding cycle shown is namely similar to that in the prior art ( 2 the US 5,641,275 and the US 5,997,264 ) funding via a relatively wide channel (reference number 154 . 152 the 12 and reference numerals 52 the 2 ) led to the containment chamber. A supply of funding through a relatively wide channel inevitably also provides a free supply of solids in the containment chamber, which is very disadvantageous, in particular when the funding is loaded with substantial amounts of solids. In the case of a stationary axis, such as the US 5,641,275 and the US 5,997,264 Once solids have entered the containment chamber, they are not immediately transported to the outer areas of the containment chamber due to centrifugal force. Such a centrifugal force could occur if a rotating shaft were used. In the case of the above-mentioned US applications, however, it is a stationary, stationary axis, so that the solids accumulating in the gap space in a pump according to the above-mentioned US applications also accumulate in the central region of the containment chamber and remain there. In the case of the stationary axis provided in the US applications, a number of grooves or notches are therefore provided for the discharge of such solids. Solids remaining to a large extent in the containment shell space could damage either the magnetic coupling in the area of the gap space or even more particularly a bearing of the shaft in the area of the slide bearing gap.

For plastic pumps according to the status The technology therefore has the problem of a sufficiently high torque transmission to ensure at the same time permanent and reliable coolant circulation. The main problem here is the introduction of solids in the circuit of the coolant circulation to prevent. This was not possible until now because of a hollow shaft for plastic pumps is unsuitable.

This is where the invention comes in It is the task of specifying a pump and a method by means of which a sufficiently high torque transfer between the delivery rotor and the conveying means is provided with a sufficiently reliable circulation of the conveying medium between the conveying space and the gap space. The pump should be effective and reasonably cheap to manufacture.

Regarding the device Object by the invention by means of a pump with a conveying medium bordering non-metallic surface solved of the type mentioned at the beginning, in the inventive means one outside the first passage and one inside the shaft lying second passage a circuit for the medium between the conveying chamber and gap space is provided, the second passage outside the middle of the wave runs.

The following is under plastic pump above all understood a pump in which the essential part of the to the medium bordering areas are of a non-metallic nature. The areas mentioned are therefore surfaces, against the medium are insulated with plastic, otherwise they are metallic and therefore susceptible to corrosion areas against the medium would act.

Under a wave in the sense of this Registration is preferably a rotatable holding means in general To understand meaning. The holding means can be a rotatable shaft as well as any other rotatable means that can be used to hold a grant on a funding side Piece and a conveyor rotor on a piece on the drive side of the agent. The conveyor is advantageously driven via the rotatable holding means, which is referred to here as a shaft.

Under a wave can also be standing, stationary Axis can be understood. However, this has certain disadvantages the construction of the pump and the circuit mentioned for the medium between funding room and gap space. These disadvantages could be accepted if necessary.

A magnetic coupling can be used a suitable type of magnet, e.g. B. permanent or electromagnets, to disposal be put.

The essential knowledge of the invention lies in being a cycle for the medium between funding room and gap space over a second outside the passage running through the center of the shaft. A middle one Passage, how it is present in a hollow shaft is theoretically also in the plastic pump mentioned possible to Additional example to the second passage. This would however, some of those related to a plastic pump the prior art, in particular the plastic pump with ceramic hollow shaft, have disadvantages mentioned. In the pump according to the invention the center of the shaft is therefore advantageously filled, i.e. not hollow. Instead of of which runs the second passage outside the middle of the shaft.

This has a number of significant advantages. This is the apparent contradiction above between a sufficiently high torque transmission and a reliable circuit at the same time of the medium canceled. The plastic pump proposed here is a targeted one and permanent fluid circulation guaranteed. This is achieved by means of the advantageously designed circuit. About that is also a complete and permanent degassing of the gap space and adjacent rooms possible. The proposed pump is above all insensitive to fluids loaded with solids and at the same time resistant in the areas bordering on the medium to be pumped it is a chemically aggressive medium, d. H. the Pump can also be particularly advantageous for solids-laden media Promote Wise. An external plain bearing flush or external lubrication is not necessary. The circulation of the medium between funding room and gap space also works with media loaded with solids reliable. Therefore it does not apply also additional External effort Lubricant and coolant. Moreover is off-center due to the second horizontal passage a positive torque transmission independent of the direction of rotation between conveyor rotor and funding possible. The arrangement of the second passage within the shaft has the Consequence that surface the shaft especially smooth and also for a plain bearing can be designed for storage in a particularly advantageous manner. Furthermore, the design of the pump has also been proven their manufacture and their dimensions as advantageous. In particular can for the proposed pump maintain the dimensions of a standard chemical pump become.

Regarding the procedure, the Object by the invention using a method of the beginning mentioned type solved, in which according to the invention the medium by means of an outside the first passage and lying within the shaft the shaft lying second passage in a circuit between delivery chamber and gap space led with the second passage outside the middle of the wave runs.

According to an advantageous development of the proposed method, the first passage has a first pressure drop from the delivery space to the gap space and the second passage has a second pressure drop from the gap space to the delivery space, so that the pumped medium is permanently forced to circulate when the pump is operating. The priority control is designed for a particularly effective control of subsidies, but the entry of solids into the circuit is prevented. In particular, the medium also lubricates and / or cools the slide bearing and / or the magnet clutch. Solids can only penetrate through the plain bearing gap, if at all. This is narrowly designed, so it allows only the smallest solids to pass through, if at all. These are ground and removed from the pump with the cooling and lubricating flow.

Advantageous further developments of proposed pump can be found in the subclaims. Give this advantageous options in detail regarding the formation of the second passage, the shaft and the formation of the drive-side part of the pump in the area of Gap and the magnetic coupling. The ones mentioned here and others the features implementing the proposed concept enlarge the advantages mentioned above and also realize further advantageous Improvements.

Regarding the design of the first and second passage, it is particularly advantageous that the first Passage in Form a first number of channels and / or the second passage in Form a second number of channels is formed. The design of the culverts inside the shaft, depending on the design, the special Pump shape and taken into account thereby the ones to be cooled and / or lubricating points on the pump. In particular, it proves turns out to be advantageous if the second passage is in the form of a bore is. This preferably has a circular cross section and can be then manufacture particularly easily. There could also be one Groove may be provided, or in addition also a half hole on the surface of the shaft. Of course you can too other forms of a second culvert can be chosen if this is for one Application as cheap prove. A semicircular or elliptical or semi-elliptical or angular second passage depending on Need as cheap prove. The second passage is favorably rectilinear along an axial direction within the shaft though outside the middle of the shaft. However, it can also be a helical or any curvature, as required second passage inside the wave as cheap prove.

The first passage advantageously has a channel on which in a plain bearing gap between a plain bearing and the wave runs especially in a plain bearing gap between a plain bearing and an outer part the wave runs. This measure leads this particularly preferred development of the proposed pump to that itself a possible for media with a high solids content Entry of solids into the containment chamber largely prevented, at least drastically reduced. The plain bearing gap acts due to its spatial Limitation in this particularly preferred development of the proposed Pump practically like a filter for the medium. While embodiments are known in the prior art, in which a can chamber from Point of the highest Pressure in the funding area a pump from over a channel freely accessible is, the proposed is in this particularly preferred development Pump the containment chamber essentially shielded from the pump delivery chamber. Regarding this constructive measure the arrangement of the first passage in the plain bearing gap between The plain bearing and shaft therefore have the effect that, on the one hand, an adequate one subsidies circulation is given in the containment chamber, on the other hand an entry of Solids is drastically reduced. Should still be solids can penetrate into the plain bearing gap, they are so small that she can be easily ground in the plain bearing. The camp is advantageous for one designed such mechanical load. Should such grated Components of solids get into the containment can or should it is a medium a slightly polymerizing or thickening medium act, there is preferably due to the proposed pump rotating shaft to be used no risk of deposition in the containment chamber. Deposits or other deposits in the containment chamber prevented with the proposed pump, since all firmer or thicker Components due to a rotating shaft in the containment chamber the centrifugal force generated by the rotating shaft is carried out immediately become. According to the particularly preferred development of the proposed pump is therefore a first passage to Transport of the funding rather small in the containment chamber, at least smaller than the second passage. In contrast, the second passage is inside and off-center the shaft is rather large, at least bigger than the first passage. This causes that after Outside worn components can be easily pushed out of the containment shell. An entry of solids into the containment shell is practically prevented, in any case drastically reduced, and a solids discharge takes place particularly light. Because of this particularly preferred training the invention can practically not accumulate solids in the containment chamber respectively.

With regard to the formation of the shaft, it proves advantageous that the shaft is formed by an inner part and by an outer part. In principle, the inner and outer part could be designed and segmented as required, as required. In particular, however, it proves to be advantageous if the outer part is formed in the form of a sleeve or casing, that is to say completely surrounds the inner part. It is particularly preferred to arrange the inner part centrally within the outer part. Basically, the multi-part design of the shaft allows the second passage to be arranged in the outer part. In this way it would not necessarily be necessary to mount the second passage in a solid shaft be made, but an outer part could be made with such a second passage. The outer part would then only be assembled with the inner part in terms of production technology to form the shaft. The outer part could be made of ceramic and / or plastic.

If necessary, it is also possible for the second Passage in addition or alternatively channels to be provided in a full wave, i.e. in a wave that is not multi-part is constructed.

The above-mentioned multi-part training the shaft allows the shaft to be advantageously connected by means of a To store plain bearings, especially on an outer part, as explained above by means of the plain bearing. The plain bearing is over a sleeve and formed a socket. The shaft is held in the bearing bushes , The sockets are advantageously held on a housing wall. For example, it could the outer part advantageous for a Plain bearings should be formed. The outer part is preferred from one for the slide bearing made of a particularly suitable material. Next the ceramic or plastic materials mentioned could do this also particularly hard materials such as carbides or sintered materials his. This proves to be particularly beneficial when solids are in the plain bearing gap should be ground between the plain bearing and the shaft. So it turns out it also turns out to be cheap, that the second passage in the shaft along an axial extent in the area of the plain bearing runs, in particular is convenient the course is limited to the area. Furthermore, the multi-part design of the shaft also that the inner part on special favorable Way for a moment transfer between conveyor rotor and subsidies is. So it turns out to be advantageous that the inner part is a metal part is. This conveniently allows a moment transfer between conveyor rotor and grants by means of a positive connection Metal part for driving the conveyor via the Wave.

The proposed concept allows in particular that the funding is attached centrally to the shaft. The funding is favorable independent direction of rotation attached, for example with an Allen screw. This has considerable advantages compared to fastening on the outer edge the shaft, as would have been necessary with a hollow shaft.

Concerning the part on the drive side the proposed pump is in particular provided that the drive side a partition extends into the gap space. In particular, the Partition formed by part of a can, which is partially between conveyor rotor and drive rotor extends into the gap space, the conveyor rotor surrounds and includes a containment chamber. It turns out to be Cheap, that the first passage one Has channel, which runs in the area of the gap. Advantageous part of the gap forms part of the first passage. This part of the first passage thus encompasses the space that is between the partition and the conveyor rotor extends. It also proves to be favorable that the second passage one Has channel, which in the conveyor rotor runs. Before all, it’s cheap that the Cycle for the medium includes the containment chamber.

Embodiments of the invention are compared below with reference to the state of the art Technology, which is also shown in part, is described. This is the exemplary embodiments not to scale, rather, the drawing, where useful for explanation, is in a more schematic form and / or slightly distorted form. With regard to supplements the teachings immediately recognizable from the drawing are based on the relevant State of the art referenced.

In particular, it must be taken into account that diverse Modifications and changes regarding the shape and details of an embodiment can, without deviating from the general idea of the invention. In the the above description, in the drawing and in the claims disclosed Features of the invention can both individually and in any combination for the realization the invention be essential. The general idea of the invention is not limited to the exact form or detail of the one shown and described below embodiment or limited to an object that would be restricted compared to that in the claims claimed subject.

While the invention has been found to be particularly useful for a particular type of magnetic clutch pump proves, based on which it is described in detail below, it should be noted that the Invention also as part of a number of other magnetic clutch pumps can be applied. So the invention can, for. B. also on one Transfer canned pump are used with electromagnets instead of permanent magnets become. Can continue Magnetic clutch pumps also have an axis instead of a shaft.

The figures of the Drawing in

1 a metallic magnetic coupling pump according to the prior art with a circuit for the medium between the pumping chamber and the gap, as is only favorable for metallic magnetic coupling pumps;

2 a plastic magnetic coupling pump according to the prior art, with a solid shaft, such as is advantageously provided to ensure sufficient torque transmission and the attachment of the funding to the shaft, but this prevents a sufficient circulation of the medium;

3 a plastic magnetic coupling pump with a ceramic hollow shaft, the egg NEN circuit for the pumped medium available, but allows only a limited torque transfer and an expensive attachment of a conveyor and a conveyor rotor;

4 a preferred embodiment of a plastic magnetic coupling pump according to the proposed concept with sufficient torque transfer and particularly favorable circulation of the medium;

5 the same embodiment of the 4 with the circuit shown.

1 shows a centrifugal pump 1 with permanent magnetic coupling 2 made of metal. This has a drive shaft 3 on what about an engine 4 (symbolically represented) driven and on a radial ball bearing 5 is stored. A drive rotor sits on this drive shaft 6 , which is designed here as an outer rotor. Via the permanent magnetic coupling unit 2 is a magnetic rotary coupling of the drive rotor to the conveyor rotor 7 formed, which is also referred to as a pump rotor, and is designed here as an inner rotor. That means the drive rotor is on the outside and the conveyor rotor is on the inside. The rotary coupling is via a gap space extending between the conveyor rotor and the drive rotor 8th away. There is a first permanent magnet on your drive rotor as part of the magnetic coupling 9 and a second permanent magnet on the conveyor rotor 10 intended.

The poles of the permanent magnets with the same name stand still 9 and 10 across from. Be a moment on the driving magnet 9 applied, it rotates by an angle φ with respect to the driven rotor 10 until an air gap torque is equal to a load torque. Due to the rotary movement, the torque curve corresponds to a sine function and reaches its maximum value with the maximum amplitude of the sine function. This maximum value is often referred to as static or as a stall torque. The usual degree of utilization of these couplings is 70% of this breaking torque. However, this strongly depends on the starting conditions, the type of drive and the physical properties of the medium. If the maximum angle corresponding to the maximum torque is exceeded, then the pole faces of the same name are increasingly compared. The force-transmitting field lines are repelled accordingly and directed to the neighboring pole of the same rotor. If the pole faces of the same name face each other completely, the coupling breaks off. As a result, the pump rotor remains 10 stand while the engine with some idle power the drive rotor 9 rotates. The motor of such a pump usually has to come to a standstill after being switched off in order to be able to put the pump back into operation.

In the gap room 8th extends the so-called can 11 with its walls 11a and 11b , In this way, the area of the pump through which the pumped medium flows is separated from the dry area of the pump. The medium 12 is in 1 indicated by arrows in the direction of flow. With the rotation of the conveying rotor, a conveying means is also attached to it 13 rotated, which is the medium 12 in a funding room 14 in the conveying direction 15 emotional. In addition to this main flow in the delivery room 14 , preferably close to the point 16 a partial flow of the highest pressure in the delivery chamber 17 of the pumped medium and the circuit for the medium between the pumping chamber 14 and gap space 8th provided. Due to the pressure drop, the pumped medium flows in part 17 first in the direction of the containment shell 18 through the gap 8th positively guided and then over the hollow shaft 19 centered on the axis 20a along the direction 21 in the funding room 14 recycled. In this way, a positively driven circuit is formed, which permanently cools and / or lubricates the bearings 22 the shaft as well as the magnetic coupling 2 guaranteed.

Because of the contactless coupling, such pumps are fundamentally suitable for conveying liquid, in particular aqueous and chemically aggressive media, which, however, must not be loaded with solids. With a metallic pump like the one in 1 is shown, the shaft can 19 advantageously form as a hollow shaft, since this shaft is made of metal. However, metallic pumps do 1 the disadvantage that they prove to be insufficiently corrosion-resistant to chemically aggressive media. In addition, a large amount of the partial flow 17 through holes (not shown here) into the containment chamber 18 are conducted so that the amount of heat generated in the metallic parts due to the high eddy current losses is dissipated. This allows solids to easily enter the containment chamber 18 reach. Solids in the pumped medium usually have to be used in metallic pumps, as well as in the US 5,641,275 and 5,977,264 , are avoided because they close the holes for the flushing liquid 17 in circulation. The lubrication of the slide bearing 22 then fails, causing the pump 1 can significantly damage.

As an alternative to this, a plastic pump is therefore according to the prior art 2 provided which is essentially similar to a metallic pump 1 the 1 is built and works on the same principle. For this reason, parts which correspond to one another in terms of their effect are provided with the same reference symbols due to the essentially identical function, although these can be designed differently. The main difference to all parts that come into contact with the medium is that they have no metallic free surface in relation to the medium in a plastic pump. Such a part, such as the impeller and pump rotor, can be made of metal but plastic coated. These parts may also be made of plastic as a solid material. In any case, a metallic part is usually insulated from the pumped medium by a suitable material. The insulation is in 2 especially as a coating 23a on the wave 23 shown. Such a pump is therefore also referred to as a plastic pump if the essential part of the surfaces of the pump coming into contact with the pumped medium is insulated from the pumped medium. This means that the metallic components of such a pump, if available, are protected from the pumped medium.

In contrast to the metallic pump 1 the 1 instructs the plastic pump 20 the 2 not a hollow but a solid shaft 23 on. This is via a plain bearing sleeve 24 and a plain bearing bush 25 towards the housing 26 the pump.

Furthermore, in contrast to the metallic pump 1 the 1 with the plastic pump 20 the 2 the impeller 13 and the conveyor rotor 7 on the wave 23 be screwed. With the present pump 20 the 2 is the conveyor rotor 7 and the wave 23 made in one piece and the impeller 13 is screwed on. The impeller could as well 13 one-piece on the shaft 23 be shaped. In many cases, a screw connection is advantageous, so that a hollow shaft has so far proven to be disadvantageous in a plastic pump. A part is also usually used for plastic pumps 17 of the flow 12 . 15 near a point of highest pressure 16 taken off and over relatively wide channels 27 in the plain bearing gap and in the gap space 8th and in the containment chamber 18 fed. Due to a lack of passage in the shaft 23 However, it cannot deliver a targeted, permanent fluid circulation like a metallic pump 1 can be achieved since, as explained above, a hollow shaft would lead to considerable disadvantages in a plastic pump. This means that there is no or insufficient fluid exchange in the containment chamber 18 is possible via the medium. Solids can be easily introduced and are deposited. Furthermore, no gas inclusions can be removed from the containment chamber. As an alternative, additional vent holes (not shown here) can be found at the uppermost point of the containment can 11 appropriate. However, fluid circulation is also not possible above this. At most, this enables partial degassing of the containment chamber. In addition, there must be no solids in the medium. They close narrow channels for the pumped medium, which serves here as a rinsing liquid. Lubrication of the plain bearings 24 . 25 , possibly also the cooling of the clutch 2 , is at risk or even fails. Solid particles that have penetrated can no longer penetrate the containment chamber 18 leave and accumulate there.

The high corrosion resistance with aggressive chemical fluids is an advantage in the case of a plastic pump and should be used.

This can be remedied in part by a plastic pump 30 the 3 created. Here, components with the same function are again provided with the same reference numerals, although the components can be designed differently. In contrast to the metallic pump of the 1 are the corresponding parts of the pump 30 the 3 Made of ceramic or plastic to improve the resistance of exposed surfaces to your fluid. Metallic parts are necessarily insulated, but this is not shown.

In particular, the plastic pump 30 a hollow shaft 29 made of ceramic with a central passage 30 intended. The torque from the drive rotor 6 driven conveyor rotor 7 via the magnetic coupling 2 is via a shaft hub connection 31 , for example a plastic key. Lubrication of the plain bearings 24 . 25 takes place as with the metallic pump 1 the 1 , In principle, therefore, circulation of the pumped medium for flushing and lubricating the drive-side part of the pump is advantageously solved, since a return by means of the central passage 32 in the ceramic wave 29 the plastic pump 3 is provided.

To enable lubrication or to avoid damage to the plain bearings, the US 5,641,275 and the US 5,997,264 a groove or notch on the surface of a ceramic stationary axis.

A crucial disadvantage of the pump 30 and the pumping of the US documents, however, is that ceramic materials always have a certain brittleness, so that a ceramic shaft 29 the pump 30 and other ceramic pumps only a very limited torque between the delivery rotor 7 and impeller 13 can transmit. In addition, in the case of the pumps mentioned above, the feather key is usually made of plastic. A key made of plastic is plastic and can also only transmit a limited torque. A secure positive connection is not possible. This applies in particular with increasing torque and at higher temperatures.

The alternative pump thus 30 an advantageous medium circulation is available (arrows in the 3 ), but you lack sufficient torque transmission.

In 4 is a preferred embodiment of a pump 40 with a non-metallic surface bordering a pumped medium, i.e. a plastic pump 40 , shown. This has a radial ball bearing 41 mounted drive shaft 42 on which is a drive rotor 43 with permanent magnets 44 wearing. This is magnetic to a conveyor rotor 45 with other permanent magnets 46 rotationally coupled. The conveyor rotor 45 sitting on one multi-part shaft 47 , The rotary coupling takes place via the permanent magnets 44 and 46 across the gap 48 time. The can extends into the gap 49 ,

The shaft has an inner part 47a and an outer part 47b on. The inner part 47a is metallic, the outer part 47b as a bearing sleeve with a circulation hole 50 , The circulation of the medium is further referred to 5 which shows the same preferred embodiment of the plastic pump. The plain bearing is in the preferred embodiment on the bearing sleeve 47b and bearing bushes 51 causes. In addition, the shaft is centered 52 held and with a thrust bearing 53 secured. The impeller 54 the pump 40 is via a central hexagon socket screw 55 on the inner part 47a the wave 47 Fixed regardless of the direction of rotation. The inner part 47a is made of metal for sufficient torque transmission and for sufficient fixing of the impeller. The impeller conveys the pumped medium 56 in the funding room 57 of a volute 58 ,

The conveyor rotor 45 and the impeller 54 are using a dovetail fit 59 or a key 60 fixed to the shaft for the greatest possible torque transmission. Both the sleeve 47b as part of the wave 47 as well as the conveyor rotor 45 have circulation holes 50 on to a circuit next to your main circuit 56 of the medium to be made available. This cycle is referred to below 5 described.

In this embodiment of the invention is the sleeve 47b made of ceramic with one or more radial through holes 50 manufactured. The through holes 50 in the ceramic sleeve 47b have as part of the cycle ( 5 ) the function of providing a permanent, positively driven funding cycle. At the same time, the ceramic sleeve works 47b also as a radial bottom bracket with regard to the bottom bracket 51 for the plain bearing 47b . 51 ,

The ceramic sleeve is located between the impeller at the front 54 and feed rotor / pump rotor 45 braced. The clamping is done by the mentioned hexagon socket screw 55 , Furthermore, the hexagon socket screw pulls with a feather key 60 the metallic core of the hub of the impeller 54 against the metallic core designed as a shaft journal 47a , The metallic core 47a forms the inner part of the shaft. The metallic shaft journal of the pump rotor is also located above this 45 pulled against the wave. The torque is transmitted non-positively through the metallic impeller hub and the shaft journal of the pump rotor.

In this embodiment, the ceramic sleeve is advantageously formed from SSiC. This has a particularly high corrosion resistance with chemically aggressive fluids and thus guarantees a very long-term durability of the plain bearing 47b . 51 ,

For others not shown here embodiments could additionally on the outside diameter the ceramic sleeve continuous grooves can be provided when a stationary stationary axis instead a rotating shaft would be used. Instead of a ceramic sleeve could in a further embodiment also a plastic sleeve be provided. Instead of a plastic or ceramic sleeve could also in a further embodiment plastic-coated shaft journal bores or grooves in the plastic coating exhibit.

Seals between the ceramic sleeve 47b as well as the shaft journal 47a take place in the embodiment shown here by O-rings or flat seals. Becomes a shaft sleeve 47b made of SSiC and the seal made of PFA, the components are resistant to all known chemical media, which makes the embodiment of the pump shown here universally applicable for all media.

In the 5 arrows indicate the cycle ( 60 . 61 . 62 . 63 . 63a . 64 . 65 ) on, for the medium as a partial flow between the pumping chamber 57 and gap space 48 is provided. Thus, in this embodiment, particularly high pressure is preferred 60 a partial flow of the medium is branched off into the circuit. The cycle extends from the pumping room 57 about the point 60 in the gaps 61 the sliding and axial bearing for the shaft 47 , Due to the narrow design of the plain bearing gap 61 the penetration of solids into the containment chamber 63a , even with a high proportion of solid matter in a medium, prevented. The plain bearing gap is only to illustrate the circuit 61 at the top of the shaft 47 shown exaggeratedly wide compared to the bottom. In fact, it is a plain bearing gap 61 , whose dimensions are designed so that it acts practically like a filter for solid particles. Furthermore, the circuit extends into the gap space 48 across the room 62 between conveyor rotor 45 and containment shell 49 as well as through a channel 63 in the conveyor rotor 45 , The further cycle is in the containment chamber 63a guided. The backflow takes place via channels 64 and through another channel 65 in the funding 54 on the type of the second passage mentioned 50 back to the funding room 57 , The canals 64 are partly in the sleeve 47b , which also serves as a radial bottom bracket for the plain bearing 47b . 51 serves. The canals 64 are wider than the channels 61 of the plain bearing gap. Should solids nevertheless penetrate into the containment chamber, they will be discharged again with greater frequency. Accumulation of solids in the containment chamber is practically prevented in this preferred embodiment.

To start up the pump, the pump is first filled. To do this, the pump is over the suction nozzle 70 flooded. The medium 56 penetrates through the holes 71 , the thrust bearing gap and the radial bearing gaps 61 in the containment chamber 63a on. The air in the containment chamber 63a escapes. If this air does not escape completely, residual air remains in the upper area of the containment chamber 63a ,

If there are solids in the medium, this is not harmful to the pump. When filling the pump, no solids can pass through the radial bearing gap due to the low internal clearance 61 in the containment chamber 63a reach. Possibly penetrate through the holes 71 small amounts of solids in the containment chamber 63a , As soon as the pump with the medium to the discharge nozzle 72 is filled, it can be switched on.

After switching on the pump 40 becomes the fluid in the containment chamber 63a centrifuged outwards. The air cushion in the upper area of the containment shell 63a is due to the higher density of the pumped medium in the middle of the containment chamber 63a pressed. Because the holes 64 in the ceramic sleeve 47b within the plain bearing columns 61 there is a pressure drop between the inlet pressure of the partial flow at the slide bearing 47b . 51 and the outlet pressure at the holes 71 on the wheel 54 available. Because of this pressure drop penetrates through the grooves 61 the gap at the thrust bearing 53 and the columns 61 the plain bearing 47b . 51 a partial flow into the containment chamber 63a , The partial flow pushes the air that is in the containment chamber 63a located through the holes 64 and 65 out again. If there are solids in the containment chamber during the filling process 63a have accumulated, they are also through the generously dimensioned holes 64 . 65 and 71 removed again.

This makes the pump insensitive to solids. A large part of the solids is also with the impeller blades 73 and a solids separator from the plain bearing gap 61 kept away. Solids that are still between the bearing gaps 61 of the thrust bearing 53 and the radial bearing 47b . 51 get completely grated. The remnants are with the partial flow through the containment chamber 63a and the holes 64 . 65 and 71 removed again.

The concept presented here thus guarantees for plastic magnetic coupling pumps a clearly defined lubrication flow for the plain bearings, an optimal one Degassing the containment chamber and without damage to the plain bearings an unrestricted funding any, chemically aggressive and solid-laden media. In addition, a direction independent of more form-fitting, through a metallic inner part of the shaft guaranteed any height Torque transmission given.

Furthermore, impeller, shaft are with Shell and inner tube sealed with a minimum of sealing elements. The construction effort the sealing ring is chosen so that the Pump the standard dimensions for Standard chemical pumps.

Claims (20)

Pump ( 40 ) with a non-metallic surface bordering a pumped medium, comprising - a shaft ( 47 ) which - on a piece of funding on the funding side ( 54 ) to promote a liquid medium ( 56 ) in a funding room ( 57 ), and - a conveyor rotor on a piece on the drive side ( 45 ) to drive the funding ( 54 ), whereby - by means of a magnetic coupling ( 44 . 46 ) magnetic coupling of the conveyor rotor ( 45 ) and a drive rotor ( 43 ) between a conveyor rotor ( 45 ) and drive rotor ( 43 ) extending gap space ( 48 ) is characterized in that - by means of an outside of the shaft ( 47 ) lying first passage ( 61 . 62 ) and a second passage inside the shaft ( 64 ) a cycle ( 60 . 61 . 62 . 63 . 63a . 64 . 65 ) for the pumped medium ( 56 ) between the funding area ( 57 ) and gap space ( 48 ) is provided, wherein - the second passage ( 64 . 50 ) runs outside the shaft center. Pump according to claim 1, characterized in that the first passage ( 61 . 62 . 63 ) in the form of a first number of channels and / or the second passage ( 64 . 50 ) is formed in the form of a second number of channels. Pump according to claim 1 or 2, characterized in that the second passage ( 64 ) is formed by means of a hole in the shaft. Pump according to one of the preceding claims, characterized in that the shaft ( 47 ) by an inner part ( 47a ) and an outer part ( 47b ) is formed, especially the outer part ( 47b ) is formed in the form of a sleeve or a casing, and the second passage ( 64 ) in the outer part ( 47b ) runs. Pump according to one of the preceding claims, characterized in that an outer part ( 47b ) is made of ceramic and / or plastic. Pump according to one of the preceding claims, characterized in that the shaft ( 47 ) is mounted by means of a slide bearing, in particular by means of the slide bearing ( 47b . 51 ) on an outer part ( 47b ) is stored. Pump according to one of the preceding claims, characterized in that the first Passage has a channel which in a plain bearing gap ( 61 ) between a plain bearing ( 51 ) and the wave ( 47 ) runs, especially in a plain bearing gap ( 61 ) between a plain bearing ( 51 ) and an outer part ( 47b ) the wave ( 47 ) runs. Pump according to one of the preceding claims, characterized in that a smallest cross section ( 61 ) of the first passage is smaller than a smallest cross section ( 50 . 64 ) of the second passage. Pump according to one of the preceding claims, characterized in that the second passage ( 64 ) in the shaft along an axial extent in the area of a plain bearing ( 47b . 51 ) runs, especially the course in the wave is essentially limited to the area. Pump according to one of the preceding claims, characterized in that the inner part ( 47a ) is a metal part, especially for driving the conveyor ( 54 ) over the wave ( 47 ) a torque transmission between the conveyor rotor ( 45 ) and funding ( 54 ) by means of a positive connection over the metal part ( 47a ) is effected. Pump according to one of the preceding claims, characterized in that the inner part ( 47a ) in the middle of the outer part ( 47b ) runs, with the outer part ( 47b ) the inner part ( 47a ) surrounds extensively. Pump according to one of the preceding claims, characterized in that the conveying means ( 54 ) in the middle of the shaft ( 47 ) is fastened, in particular fastened independently of the direction of rotation, preferably with an Allen screw ( 55 ) is attached. Pump according to one of the preceding claims, characterized in that on the drive side there is a partition in the gap space ( 48 ) extends. Pump according to one of the preceding claims, characterized in that a partition wall from part of a containment shell ( 49 ) is formed, which is partially between the conveyor rotor ( 45 ) and drive rotor ( 43 ) in the gap space ( 48 ) and which extends the conveyor rotor ( 45 ) surrounds and a containment chamber ( 63a ) includes. Pump according to one of the preceding claims, characterized in that the first passage has a channel ( 62 ), which in the area of the gap ( 48 ), especially the canal ( 62 ) over a space between a partition and your conveyor rotor ( 45 ) is formed. Pump according to one of the preceding claims, characterized in that the second passage ( 50 . 63 ) a channel ( 63 ), which in the conveyor rotor ( 45 ), in particular the channel runs through a hole ( 63 ) in the conveyor rotor ( 45 ) is formed. Pump according to one of the preceding claims, characterized in that the circuit ( 60 . 61 . 62 . 63 . 63a . 64 . 65 ) the containment chamber for the pumped medium ( 63a ) includes. Method for providing a circuit of a delivery medium in a pump with a non-metallic surface bordering a delivery medium, which pump ( 40 ) - a wave ( 47 ), which - on a conveyor-side piece of funding ( 54 ), by means of which a liquid medium ( 56 ) in a funding room ( 57 ) is conveyed, and - a conveyor rotor on a piece on the drive side ( 45 ) by means of which the funding ( 54 ) is driven, whereby - by means of a magnetic coupling ( 44 . 46 ) magnetic coupling of the conveyor rotor ( 45 ) and a drive rotor ( 43 ) between a conveyor rotor ( 45 ) and drive rotor ( 43 ) extending gap space ( 48 ) is effected, characterized in that - the pumped medium ( 56 ) by means of an outside of the wave ( 47 ) lying first passage ( 61 . 62 ) and by means of a second passage located inside the shaft ( 64 ) in a cycle ( 60 . 61 . 62 . 63 . 63a . 64 . 65 ) between the funding area ( 57 ) and gap space ( 48 ) is guided, whereby - the second passage ( 64 ) runs outside the shaft center. Method according to claim 18, characterized in that the first passage has a first pressure drop from the delivery chamber ( 57 ) to the gap space ( 48 ) and the second passage has a second pressure drop from the gap space ( 48 ) to the funding area ( 57 ), so that the pumped medium is permanently forced to circulate when the pump is operating. Method according to one of claims 18 or 19, characterized in that the conveying medium the slide bearing ( 47b . 51 ) and / or the magnetic coupling ( 44 . 46 ) additionally lubricates and / or cools.