Eccentric screw compressor with exposable rotor connector

Abstract

An eccentric screw pump has a stator, a rotor in the stator, a drive for the rotor, and a pump housing between the stator and the drive and having an opening between for receiving the medium being pumped. A releasable drive-end coupling connects a connecting shaft of the drive to a coupling rod, and a rotor-end releasably connects the coupling rod to the rotor at a separation point. A rotor stub connects the rotor to the rotor-end coupling and is separable from the rotor at the separation point. A drive-end housing collar secures the pump housing to the drive. A rotor-end housing collar has a fixed first element fixed relative to the pump housing and an axially displaceable second element that is releasably fixable to the stator and that can be pushed axially toward the housing opening of the pump housing onto the first element to expose the separation point.

Claims

1. An eccentric screw pump comprising: a stator defining an axis; a rotor extending along the axis and rotating in the stator; a drive for rotating the rotor; a pump housing having a stator end connected to the stator, a drive end connected to the drive, and a housing opening between the stator end and the drive end for receiving the medium being pumped; a connecting shaft connected to the drive; a coupling rod in the pump housing; a releasable drive-end coupling at the drive end of the pump housing and connecting the connecting shaft to the coupling rod; a rotor stub rotationally connected to the rotor and extending axially toward the coupling rod; a rotor-end coupling at the stator end of the pump housing and releasably connecting the coupling rod at a separation point to the rotor stub; a spacer ring between the rotor and the rotor stub; a drive-end housing collar securing the pump housing to the drive; and a rotor-end housing collar having a fixed first element fixed relative to the pump housing and an axially displaceable second element that is releasably fixable to the stator and that when pushed axially toward the housing opening of the pump housing onto the fixed first element exposes the separation point, the rotor stub extending through the displaceable second element into the fixed first element.

2. The eccentric screw pump according to claim 1, wherein the displaceable second element is tubular and substantially cylindrical and telescopes axially with the fixed first element.

3. The eccentric screw pump according to claim 1, further comprising: fasteners securing the displaceable second element to the fixed first element.

4. The eccentric screw pump according to claim 1, wherein the fixed first element and the second displaceable element are formed by first and second telescopically displaceable sleeves.

5. The eccentric screw pump according to claim 1, further comprising: tie rods reinforcing the stator axially and extending between a first flange and a second flange axially flanking the stator and fitted in notches open at outer edges of the flanges so that the tie rods can be removed radially outward from the notches in the vicinity of the flanges.

6. The eccentric screw pump according to claim 1, wherein the stator has a substantially constant wall thickness over substantially all of its entire axial length.

7. The eccentric screw pump according to claim 1, wherein the rotor is tubular over at least a portion of its length.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention is explained below with reference to a drawing that shows two embodiments. In the drawing,

(2) FIG. 1 is a (partial) vertical section through an eccentric screw pump according to the invention,

(3) FIG. 2 is a large-scale detail from FIG. 1 showing a rotor-end coupling exposed, and

(4) FIG. 3 is a large-scale detail from a modified embodiment of the pump according to FIG. 1.

SPECIFIC DESCRIPTION OF THE INVENTION

(5) The drawing shows an eccentric screw pump that, in its basic construction, has a stator 1, a rotor 2 rotating in the stator 1 about an axis P, and a drive 3, 14 for the rotor 2. The eccentric screw pump has a (central) pump housing 4 also referred to as a suction housing. In this case, the pump housing 4 is connected at a suction end 7 to a suction end of the stator 1. On the opposite end of the pump housing 4, its drive end 8 is connected to the stator 1 as a connector also referred to as a pressure port 5. The pump housing 4 has a housing opening 6 used, for example, as an inlet opening for the medium being pumped, so that, depending on the operating direction, the medium is conveyed for example from the pump housing 4 via the stator/rotor to the pressure port 5. The drive 3, 14 is equipped with an integrated drive shaft (not shown) connected to a connecting shaft 9. In this embodiment, this connecting shaft 9 is a plug-in shaft. The rotor 2 is connected via a coupling rod 10 to the connecting shaft 9, the coupling rod 10 being connected via a drive-end coupling 11 to the connecting shaft 9 and via a rotor-end coupling 12 to the rotor 2. To seal the pump housing liquid-tight from the environment and/or against the drive, the connecting shaft 9 is surrounded by a shaft seal 13. This shaft seal 13 is for example a mechanical seal.

(6) A connecting housing 14, also referred to as a bonnet, is between the pump housing 4 and is part of the drive 3, 14. Such a connecting housing 14 supports the pump housing 4 and the drive 3, 14. Accordingly, the connection housing 14 can be fastened to a base plate 15. The shaft seal 13 is connected to this connecting housing 14.

(7) A drive end 8 of the pump housing 4 has a drive-end tubular housing collar 16 to which the connecting housing 14 is connected, with the drive-end coupling 11 being in this drive-end housing collar 16.

(8) In addition, the pump housing 4 has a stator end 7 formed by a stator-end (tubular) housing collar 17 to which the stator 1 is connected, with the stator-end coupling or rotor-end coupling 12 being inside this stator-end housing collar 17.

(9) In that case, the coupling rod 10 is separably connected by a releasable drive-end connector to the connecting shaft 9 and separably connected to the rotor 2 by a releasable rotor-end connector. On the drive end, this releasable connector is formed by the drive-end coupling 11.

(10) The optionally separable rotor-end coupling 12 is provided on a rotor end of a separable rotor stub 21. In addition, however, a (further) separation point 20 is provided in addition to the coupling 12, so that the rotor 2 can be separated from the coupling rod 10 by separation at the separation point 20. In the illustrated embodiment, the rotor 2 is connected to the coupling rod 10 and to the coupling 12 with interposition of the separable rotor stub 21. The rotor stub 21 thus carries one half of the coupling 12 on its drive end. The rotor stub 21 is releasably connected to the rotor 2 on its opposite rotor end. This will be discussed further below.

(11) In the embodiment illustrated in FIG. 1, the stator-end housing collar 17 has a fixed first element 17a on the one hand and a displaceable second element 17b on the other hand. The displaceable second element 17b can be slid axially toward the housing opening 6 of the pump housing 4 onto the first element 17a to expose (and separate) the rotor-end connector. The displaceable second element 17b is tubular and, in this embodiment, substantially cylindrical; it can be telescoped onto the fixed element 17a, thereby exposing the rotor-end connector, namely the separation point 20. The rotor and coupling rod can then be separated without disassembling the coupling 12 itself. The rotor and stator can be easily replaced after the housing part 17b has been pushed onto the housing part 17a and the separation point has been released.

(12) In the illustrated embodiment, the separation point 20 is in effect integrated into the rotor 2, in that the rotor stub 21 is releasably connected at one end to the rotor 2, thus forming the separation point 20. The rotor stub 21 has a fixed length, so that it acts as an extension of the rotor 2 and thus also bridges the displaceable element 17b. In any case, the coupling 12 is inside the fixed element 17a. Consequently, the rotor stub 21 extends through the first element 17a and into the second element 17b. For that purpose, the rotor stub 21 carries one half of the coupling 12. The other half of the coupling is part of the coupling rod 10. The rotor stub 21 has a flange 32 at its end facing toward the rotor 2 and secured to the rotor 2 by screws 33. In this embodiment, it can be seen that this screwing is performed with interposition of a two-part spacer ring 22. This spacer ring 22, which can consist of two half-rings, can be removed after the screws 33 are loosened, so that a free space and thus an axially extending displacement gap for the rotor 2 is formed, thus facilitating disassembly. This will be discussed further below.

(13) In addition, it can be seen that at least one seal ring 18 is provided between the first element 17a and the second element 17b that seals the first element 17a against the second element 17b in a liquid-tight and pressure-tight manner, particularly in the assembled state shown in FIG. 1. In this embodiment, the seal 18 is on the outer surface (for example in a groove) on the first element 17a or on an adapter piece 23 connected thereto. In fact, FIG. 1 shows that the adapter piece 23 has a flange 24 at the end and is connected to the fixed first element 17a. This adapter piece 23 carries the seal 18. The displaceable connecting part 17b is attached to this adapter piece 23 by mounting screws 25, i.e. it is connected by the adapter piece 23 with the mounting screws 25 to the flange 24.

(14) Alternatively or in addition, the displaceable connecting part 17b is fastened on the rotor end by mounting screws 26 to a stator-end flange 29 or adapter piece 27.

(15) In this respect, FIG. 1 shows that in the illustrated eccentric screw pump a suction housing known from the prior art can be used that already has the fixed element 17a, and the displaceable element 17b is provided as an additional component, so to speak, to form the suction housing 4 according to the invention 4.

(16) Moreover, it can be seen that the stator 1 is secured by tie axially extending rods 28 between a first flange 29 and a second flange 30. The first flange 29 is on the end toward of the pump housing 4. The second flange 30 is on the opposite end of the pump housing 4 of the stator. It is part of the connector or pressure port 5. The flanges 29, 30 have notches 31 through which the tie rods 28 are passed. According to the invention, these notches 31 are notches that are open radially outward, for example slots, at least in the vicinity of one of the flanges, so that the tie rods 28 can be removed radially outward in the vicinity of this flange. The tie rods 28 can be fixed and/or tensioned with respective nuts 28′.

(17) In the illustrated embodiment, the rotor and/or stator is disassembled as follows:

(18) First, the mounting screws 25 and 26 of the displaceable element 17b are withdrawn so that the displaceable element 17b can then be pushed in the direction of arrow P onto the first element 17a. As a result, the region of the separation point 20 is exposed. The screws 33 can then be unscrewed and the spacer ring 22 removed (see FIG. 2). This creates the above-described axial clearance between the rotor 2 and the rotor stub 21 separated therefrom. Now the tie rods 28 can be loosened and removed. Meanwhile or subsequently, it is possible to displace the adapter piece 27 with the attached flange 29 axially as shown by the arrow P. By virtue of the free space now gained, rotor 2 and stator 1 can also be displaced toward the arrow P and removed. All in all, it is possible to replace rotor and/or stator without dismantling the coupling 12 and, in particular, without disassembly of the pressure port 5 and suction housing 4.

(19) Moreover, it can be seen that, in the illustrated embodiment, the elastomeric stator 1 has a substantially constant wall thickness over its entire length or over substantially its entire length. The same applies to the illustrated stator casing 1′ (made of metal). In this embodiment, the stator 1 is securely connected to the casing 1′, for example vulcanized therein.

(20) The illustrated pump can be part of a pump system and/or of a drainage system that can be used in mining, for example, in which case such a pump system comprises at least the depicted pump and an unillustrated drainage tank.

(21) Particular importance is attached to the rotor assembly that can consist of the rotor 2 with the rotor stub 21 and the spacer ring 22.

(22) A second embodiment of the invention is partially illustrated in FIG. 3. This second aspect of the invention relates to the drive end of the pump housing. The drive-end housing collar 16 consists here of a first, fixed element 16a and a second, displaceable element 16b. In the illustrated embodiment, the second element 16b is axially displaceable. Axial displacement of the second element 16b exposes the region of the drive-end coupling 11 and thus makes it accessible. Displacement of the second element 16b takes place axially toward the first element 16a and hence toward the inlet opening 6 of the pump housing 4.

(23) At least one seal 18′ is provided between the first element 16a and the second element 16b. After the second element 16b is pushed onto the first element 16a, then the sleeve 19 of the drive-end coupling 11 can be removed and the coupling disassembled. The coupling rod 10 can then be displaced and/or pulled out together with the attached rotor 2 away from the drive end 2. It is also possible to disassemble and/or replace the connecting shaft and/or the mechanical seal.