Rotary pump impeller

Abstract

The invention relates to a rotary pump impeller (1) having a non-metallic impeller part (7) and a metallic hub part (8) connected to the impeller part (7), the hub part being arranged on a shaft (5), wherein according to the invention a detachable connection exists between the impeller part (7) and the hub part (8).

Description

Technical Field

[0001] The invention relates to a rotary pump impeller having a non-metallic impeller component and a metallic hub component connected to the impeller component, the hub component being arranged on a shaft. Background Art

[0002] Rotary pump impellers made entirely of metal are usually fastened to the shaft in such a way that they are pushed onto the shaft end with their hub bore and pressed against the shoulder of the shaft by means of a nut. Such a fastening method is disadvantageous in the case of rotary pump impellers according to the preamble of the invention, since these comprise non-metallic impeller parts. Many non-metallic materials, such as polymer castings or plastics, tend to flow under pressure.

[0003] DE 44 44 965 A1 describes a rotary pump impeller, which includes a non-metallic impeller component and a metallic hub. The hub is a component arranged on the transmission shaft and surrounds the transmission shaft. The hub is provided with a central receiving opening. The receiving opening has a thread into which the shaft end can be screwed. The impeller component formed of plastic is formed on the hub. The hub has a ring, which is perforated and injection-molded with the plastic material of the impeller component. In this rotary pump impeller, there is an unbreakable connection between the hub and the impeller component.

[0004] DD 18 758 describes a completely different possible approach for fastening an impeller made of ceramic material. In this approach, unlike the impeller of a rotary pump according to the preamble of the invention, no hub is used. Instead of the hub, an intermediate flange is used. This intermediate flange is arranged between the shaft end and the impeller. The impeller and the intermediate flange are provided with a hole, in which a stud is arranged, which is provided with a head at one end and a thread at the other end, onto which a nut is screwed. By screwing the nut onto the thread, the impeller and the intermediate flange are tensioned toward each other. The intermediate flange is itself connected to the shaft by screwing. For this purpose, the shaft is constructed with a flange ring at one end, in which a hole for a screw connection between the flange and the shaft is arranged. This structural design of the fastening by means of an intermediate flange is very cumbersome and awkward, because the intermediate flange is not arranged on the shaft, in contrast to the hub, but is placed at the shaft end between the shaft and the impeller.

[0005] DE 2 319 463 describes a rotor for a pump for cooling an internal combustion engine. The rotor is formed by a metal hub which is pushed onto the shaft in a press fit. The impeller part is cast onto this metal hub. The impeller part is formed from a thermosetting resin mixture. Even with this design, an irreversible, secure connection is established between the hub and the impeller part.

[0006] DE 76 10 913 describes a rotary pump with an impeller made of plastic. A disk made of metal is arranged in the hub region of the impeller. The impeller has a metal bushing for support, to which the disk is fastened. The disk is completely embedded in the plastic of the impeller. As a result, an inseparable unit exists between the plastic impeller and the metal disk. Summary of the invention

[0007] The object of the present invention is to provide a rotary pump impeller which can be repaired again at low cost when wear occurs. Furthermore, the repair work should be able to be carried out quickly and at low cost. The rotary pump impeller should be able to be produced at low cost and have high quality.

[0008] This object is achieved according to the invention in that a detachable connection exists between the impeller part and the hub part.

[0009] Unlike conventional rotary pump impellers, the non-metallic impeller component is not cast around a metallic hub. As an alternative, the impeller component and the hub are detachably connected to each other via a driver element. The hub is preferably a metallic component constructed in one piece.

[0010] In another embodiment, the entraining element is constructed in multiple parts. Preferably, it is a two-part embodiment. Preferably, the entraining element has a sleeve and a connecting element, with which a reliable screw connection can be established.

[0011] Advantageously, the sleeve is arranged in a recess at an end side of the impeller component, in particular at the end side on the shaft side. Preferably, the recess refers to a hole portion, which is added to the non-metallic impeller component, wherein in particular a circular hole portion is suitable. For this purpose, a plurality of holes can be added along a circular arrangement at the end side of the impeller component, for example in the region of the carrier plate. Here, it has been proven to be appropriate that the number of the holes corresponds to the number of blades of the impeller component. In addition, the recess is preferably added to such a position of the carrier plate at which the blade acts. After the recess is added to the non-metallic impeller component, the sleeve of the entraining element is placed in the recess and fastened there. In addition, the sleeve can be pressed and / or glued into the recess, for example. Here, the sleeve is placed in the recess of the impeller component without clearance.

[0012] As an alternative, it is advantageous if the sleeve is cast into the end face of the impeller part, thereby making it possible to dispense with the drilling step.

[0013] In both cases it is advantageous if the sleeve has a suitable protection against rotation.

[0014] In another embodiment, the connecting element is arranged at the ring of the hub and at least partially engages in the sleeve. Preferably, the connecting element is screwed into the sleeve. Thus, a reliable connection is established between the impeller part and the hub.

[0015] Preferably, the connecting element is a screw. In this variant, the sleeve is provided with an internal thread into which the external thread of the connecting element configured as a screw is embedded.

[0016] The screw preferably has a conical end and is placed in a bore at the ring of the hub and then screwed into the sleeve. The bore has a countersunk end that is designed complementary to the conical end. This results in a play-free or largely play-free design in which the individual parts of the entrainment element are connected to one another in a releasable manner.

[0017] By means of the inventive concept of splitting the drive element having a sleeve which is fixed in a non-metallic impeller part in an unreleasable manner in a recess and a connecting element which establishes a releasable connection between the sleeve and the metallic hub, it is possible, in the event of wear phenomena on the impeller of a rotary pump, to replace only the non-metallic impeller part including the sleeve arranged therein and to continue to use the metallic hub. This is therefore particularly suitable since wear phenomena primarily occur on the non-metallic impeller part. In particular, wear phenomena occur on the blades of the impeller part which are in direct contact with the partially aggressive flow medium. Compared to replacing the entire impeller of a rotary pump including the metallic hub, it is clearly more suitable to replace only the non-metallic impeller part.

[0018] A further advantage of the design according to the invention is that stresses no longer occur in the rotary pump impeller according to the invention, which stresses occur in conventional rotary pump impellers formed from polymer castings during casting due to different thermal expansion values ​​of the impeller part and the hub.

[0019] Preferably, the hub has a projection which projects into the impeller part. The projection is hollow cylindrical and surrounds the shaft. A ring is connected to the hollow cylindrical projection of the hub.

[0020] The projection projects into the hub of the impeller part, while the ring of the hub part is oriented parallel to the shaft-side end face of the impeller part and rests against the end-side surface of the impeller part.

[0021] In one variant of the invention, the ring is further adjoined by a projection which is likewise hollow-cylindrical in design and thus surrounds the shaft.

[0022] Preferably, the metal hub has at least one groove on its inner side, into which a flat key engages, which establishes a connection between the shaft and the hub for transmitting torque.

[0023] In a variant of the invention, a disk is arranged at the shaft end for fixing the impeller part. For this purpose, the non-metallic impeller part preferably has a circular recess on the flow side, into which the disk is positioned. The disk has holes along its circumference, for example. The disk is fastened to the shaft end through the holes by means of suitable screws. As a result, the hub and impeller part are tensioned relative to each other.

[0024] When assembling the impeller of the rotary pump, proceed as follows:

[0025] First, the metallic hub and the non-metallic impeller part are connected. The preassembled two-part rotary pump impeller is pushed onto the shaft end.

[0026] The impeller part and the hub part are then braced relative to one another by means of the disk, which is fastened to the shaft end.

[0027] Preferably, a cover is arranged on the disk on the flow side. Since the cover is in contact with the flowing medium, it is generally made of a corrosion-resistant material.

[0028] In a particularly suitable embodiment of the invention, the impeller part is formed from a ceramic material. Preferably, a ceramic-plastic composite material is suitable for this purpose. It has proven to be particularly suitable here if it comprises silicon carbide particles arranged in a polymer matrix.

[0029] The metallic hub is preferably formed from a stainless duplex steel casting.

[0030] The method for producing and assembling the impeller of a rotary pump according to the invention comprises the following steps:

[0031] The non-metallic impeller component is preferably produced by means of a casting method.

[0032] - a depression is introduced into the impeller part, preferably by means of a hole along the circumference at the shaft-side end face of the impeller part,

[0033] The sleeve is preferably inserted into the recess and fixed in place in the impeller part by pressing and / or gluing the sleeve into the recess.

[0034] As an alternative, the sleeve is cast in during the production of the non-metallic impeller part.

[0035] - Inserting the metallic hub into the non-metallic impeller component, attention being paid to the alignment of the bore and the internal thread of the sleeve.

[0036] - Insert the connecting element into the hole along the ring of the hub and screw the connecting element into the sleeve. A thread securing portion is provided.

[0037] - Push the preassembled rotary pump impeller onto the shaft end until it comes to rest against the ring of the hub.

[0038] - The impeller part and the hub are tensioned by means of a disk which is screwed onto the shaft end.

[0039] - Fasten the cover onto the assembled rotary pump impeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Further features and advantages of the invention are apparent from the description of the exemplary embodiments with the aid of the drawings and from the drawings themselves. In the drawings:

[0041] Figure 1 is an axial section through the housing of a rotary pump with a rotary pump impeller arranged therein,

[0042] Figure 2 is an exploded view of a rotary pump impeller with a shaft,

[0043] Figure 3 An axial section through the impeller of a rotary pump at the end of the shaft. DETAILED DESCRIPTION

[0044] Figure 1 The rotary pump impeller 1 is shown, which is arranged in a rotary pump housing 2. The housing 2 comprises a suction opening 3, through which the feed medium is sucked in and conveyed by means of the rotary pump impeller 1 in the direction of an outflow opening 4 and subsequently leaves the rotary pump.

[0045] The rotary pump impeller 1 is arranged on a shaft 5. The shaft 5 is set in rotation by a motor (not shown). The torque is transmitted via two flat keys 6 to the metal hub 8 and via the entraining element 12 to the non-metallic impeller part 7 of the rotary pump impeller 1.

[0046] The rotary pump impeller 1 is formed from a non-metallic impeller component 7 and a metallic hub 8. In the exemplary embodiment, the non-metallic impeller component 7 is made of a ceramic-plastic composite material, in which silicon carbide particles are embedded in a polymer matrix.

[0047] The hub 8 is made of stainless dual-phase steel casting having a ferrite-austenite structure.

[0048] The non-metallic impeller component 7 is of one-piece construction and is produced in a casting process. It has a carrier plate 9 on which blades 10 are integrally formed. In the exemplary embodiment, this is a radially rotating pump impeller.

[0049] Figure 2 The three-dimensional exploded view of the rotary pump impeller 1 is shown with the end of the shaft 5. According to the invention, the non-metallic impeller component 7 has a recess 11. The recess 11 is a hole which is introduced into the impeller component 7 after or even before complete hardening or which is then finished if the hole has been precast during production.

[0050] Figure 3It is shown that in the assembled state, the entraining element 12 is embedded in the recess 11. Each entraining element 12 is formed by a sleeve 13 and a connecting element 14. The sleeve 13 is a hollow cylindrical body that is closed at one end. Each sleeve 13 has an internal thread. The connecting element 14 is designed as a screw that has an external thread.

[0051] As an alternative, the sleeve 13 can be cast in at the shaft-side end face of the impeller part 7 .

[0052] Figure 2 It is shown that the hub 8 has a ring 15 which is provided with a plurality of holes 16 along its circumference.

[0053] When the rotary pump impeller 1 is mounted on the shaft, it is carried out as follows:

[0054] First, the sleeve 13 is introduced into the depression 11. A suitable adhesive or epoxy resin compensates for tolerances and secures.

[0055] The hub 8 is then pushed into the impeller part 7 until the surface 19 of the impeller part 7 comes into contact with the ring 15 of the hub 8. The alignment of the bore 16 and the internal thread in the sleeve 13 must be taken into account.

[0056] The connecting element 14 is then introduced into the bore 16 and screwed and secured into the sleeve 13 which is arranged in the recess 11 .

[0057] In order to further fix the hub 8 to the impeller component 7, a screw 20 can also be screwed into another threaded sleeve or threaded hole 21 provided for this purpose in the non-metallic material of the impeller component 7, and when the sleeve 13 is not pressed into or glued into the recess 11, it can be used, for example, as a conveying safety part or an assembly aid.

[0058] The preassembled rotary pump impeller is pushed onto the end of the shaft 5. The shaft 5 is connected to the hub 8 in a rotationally fixed manner via the key 6, wherein the key 6 engages in a groove 17 of the hub 8. The groove 17 extends in the interior of the hub 8 in the axial direction.

[0059] Next, the disk 23 is fastened to the end side of the shaft 5 by means of screws 24. In addition, a hole 25 is provided in the disk 23, through which the screw 24 is inserted and then embedded in a hole provided with an internal thread at the end side of the shaft 5. The screw 24 is a cylindrical head screw. By screwing the screw 24, the hub 8 and the impeller part 7 are tensioned relative to each other.

[0060] Finally, the cover 26 is screwed into the central hole 27, which is provided with an internal thread. For this purpose, the cover 26 has a journal 28, which is provided with an external thread.

[0061] Figure 3 It is shown that an elastomer ring 29 can be arranged between the disk 23 and the impeller part 7. By tightening the screw 24, tensioning is effected relative to this elastomer ring 29. As a result, the "flow" of the non-metallic impeller part 7 is impeded.

[0062] exist Figure 3 It can be seen that an O-ring 30 is arranged between the cover 26 and the disk 23. An O-ring 31 is present between the cover 26 and the impeller part 7. Likewise, an O-ring 32 is arranged between the ring 15 of the hub 8 and the face 19 of the impeller part 7.

[0063] List of Reference Numerals

[0064] 1 Rotary pump impeller

[0065] 2 Shell

[0066] 3 Suction port

[0067] 4 Outlet

[0068] 5 Axis

[0069] 6 Flat key

[0070] 7. Working wheel parts

[0071] 8 Hub

[0072] 9 Loading plate

[0073] 10 blades

[0074] 11 Depression

[0075] 12 Driving elements

[0076] 13 Sleeve

[0077] 14 Connecting elements

[0078] 15 rings

[0079] 16 Hole with tapered end

[0080] 17 Groove

[0081] 18 Protrusion

[0082] 19 faces

[0083] 20 Screws

[0084] 21 Threaded holes

[0085] 22 Shen Duan

[0086] 23 Plates

[0087] 24 Screws

[0088] 25 Hole

[0089] 26 Hood

[0090] 27 Hole

[0091] 28 Threaded journal

[0092] 29 Elastomer ring

[0093] 30 O-ring

[0094] 31 O-ring

[0095] 32 O-ring.

Claims

1. A rotary pump impeller (1) having a non-metallic impeller component (7) and a metallic hub (8) connected to the impeller component (7), the hub being arranged on a shaft (5), It is characterized in that There is a direct, detachable connection between the impeller part (7) and the hub part (8). The impeller part (7) and the hub part (8) are axially connected to each other via a driver element (12) in a rotationally fixed and detachable manner. The entrainment elements (12) each have a sleeve (13) which is arranged in a recess (11) on the end face of the impeller part (7) and a connecting element (14) which is designed as a screw.

2. The rotary pump impeller (1) according to claim 1, characterized in that The sleeve (13) is cast into the end face of the impeller part (7).

3. The rotary pump impeller (1) according to claim 1, characterized in that The connecting element (14) is arranged on a ring (15) of the hub (8) and engages at least partially in the sleeve (13).

4. The rotary pump impeller (1) according to claim 1, characterized in that The hub part (8) has a projection (18) which projects into the impeller part (7).

5. The rotary pump impeller (1) according to claim 3 or 4, characterized in that The ring (15) of the hub part (8) lies against an end surface (19) of the impeller part (7).

6. A method for producing a rotary pump impeller (1) according to any one of claims 1 to 5.

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