WO2003091572A1

WO2003091572A1 - Centrifugal pump, in particular spirally-housed centrifugal pump for a heat exchange medium

Info

Publication number: WO2003091572A1
Application number: PCT/EP2002/004667
Authority: WO
Inventors: Stefan Werner
Original assignee: Allweiler Ag
Priority date: 2002-04-26
Filing date: 2002-04-26
Publication date: 2003-11-06
Also published as: US20060165522A1; AU2002302582A1

Abstract

The invention relates to a centrifugal pump, in particular a spirally-housed centrifugal pump for a heat exchange medium, comprising a spiral housing (14) that has an impeller (40), a housing cover (18) and a housing shoulder (34) allocated thereto for a pump shaft (35, 36, 36a), which is equipped with a journal (76, 76a) that lies close to the spiral housing (14), in addition to a shaft seal (56) located at a distance from said journal in a sealing chamber (48). The invention is characterised in that parts of the housing cover (18) form a journal well (28) that houses the journal (76, 76a), a tubular section (32) that surrounds the pump shaft (35, 36, 36a) and acts as a thermal barrier, in addition to support ribs (26) or similar profile elements that are arranged at intervals in a peripheral direction. The journal well (28) is held at a distance from the impeller (40) by means of the tubular section (32) that surrounds the pump shaft (35, 36, 36a) and the housing shoulder (34), which is attached to the housing cover (18), or to an annular edge (30) carried by the support ribs (26) of said cover, delimits the sealing chamber (48) for the shaft seal (56).

Description

DESCRIPTION

Centrifugal pump, in particular a spiral casing centrifugal pump for a heat transfer medium

The invention relates to a centrifugal pump - in particular a spiral housing centrifugal pump - for a heat transfer medium, with a spiral housing having an impeller, a housing cover and an associated housing attachment for a pump shaft, which has a shaft bearing close to the spiral housing and a spacing therefrom is fitted in a 1S seal shaft seal.

Such centrifugal pumps are described, for example, in a brochure by the applicant for the NHT series for heat transfer oils up to 350 ° C. A spiral housing for an impeller is by means of a

Throttle section with SD outer ribs connected to a bearing housing. The impeller is attached to one end of a pump shaft that runs in that throttle section. A slide bearing made of silicon carbide is arranged between this and the impeller and one after the throttle section

SS mechanical seal followed by a roller bearing. It is a horizontal spiral housing centrifugal pump in process construction, which is single-flow, single-stage. The pump-side silicon carbide plain bearing is lubricated by the liquid, and on the drive side a grease-lubricated

3D ball bearing used.

Knowing this state of the art, the inventor has set himself the goal of creating a centrifugal pump of the type mentioned at the beginning which is simple to manufacture and which is inexpensive and particularly easy to use.

BESTATIGUNGSKOPIE The teaching of the independent claim leads to the solution of this task; the subclaims indicate inexpensive further training. In addition, all combinations of at least two of the features disclosed in the description, the drawing and / or the claims fall within the scope of the invention.

According to the invention, a bearing pot that receives the shaft bearing, a pipe section surrounding the pump shaft as a heat barrier, and so-called stand ribs or the like, which are arranged at a distance from one another in the circumferential direction, are parts of the housing cover. These features enable a simple construction of the pump with only two pressure-bearing parts for the bearing bracket housing - consisting of the housing cover and housing attachment - as well as a particularly high stability of the bearing bracket housing.

In addition, the bearing cup should be kept at an axial distance from the impeller by the pipe section surrounding the pump shaft.

The sealing space for the shaft seal is advantageously delimited by the housing attachment, which is preferably attached to the housing cover or to an edge ring carried by its stand ribs and surrounding the longitudinal axis of the pump; the latter is connected to the stand ribs at their ends remote from the base area of the housing cover, preferably integrally formed thereon.

Between the spiral housing and the sealing space mentioned there is a framework-like rib arrangement consisting of those stand ribs which should be inclined towards the longitudinal axis from the spiral housing at a preferred angle of 40 ° to 45 ° and - at a radial distance from one another - surround the bearing pot and the heat barrier and together with them form the housing cover. For this purpose, it has proven advantageous to increase the cross-sectional height of the stand ribs, which preferably run in axial planes which penetrate the longitudinal axis of the pump, towards the mechanical seal, in order to increase stability 5 and to minimize heat losses.

According to a further feature of the invention, the sealing space should adjoin the shaft bearing. Among other things, this ensures that the bearing is adequately supplied with lubricant. In addition, the bearing contributes to the circulation of the medium in the seal chamber for the winding and cooling of the seal.

In order to expand the use of the centrifugal pump according to the invention and its 15 possible combinations, at least one stop stage for a further pump part directed away from the spiral housing can be arranged on the housing cover; this stop step should preferably be a front ring molded onto the housing cover. An associated pump part SD can, moreover, be a lantern encompassing the bearing support housing, attached to the stop step (s) or the front ring, to which a motor is attached.

It has proven advantageous to have the stop step or Ξ5 the front ring protrude from a ring flange which surrounds the stand ribs and which is attached to their transition to a base area of the housing cover.

In the context of the invention is a centrifugal pump with a 3D sealing ring of the - designed as a mechanical seal - shaft seal, which rotates on a mating ring provided on the house; the latter is arranged for the sealing ring in a molded socket of the housing attachment that protrudes axially into the sealing space. At least one opening inclined with respect to the longitudinal axis of the pump is intended to close the molded connector - an axial length corresponding to approximately 35 half the axial length - of the sealing space Screw plug to be assigned; the longitudinal axis of this opening advantageously defines an angle of approximately 45 ° with the longitudinal axis of the pump. The mechanical seal is therefore moved forward within the sealing space in order to provide sufficient space for collecting air or outgassing of the conveying medium, especially in the case of vertical installation. The described arrangement of the opening with the screw plug enables the venting of the sealing space 0 in a simple manner, both when the pump is installed horizontally and vertically.

The heat of friction of the mechanical seal is expediently dissipated to the environment through a large surface area of the surrounding seal space and a large liquid volume in the seal space.

According to the invention, the shaft bearing is designed as a plain bearing with a ratio of the length of the bearing bush to the D diameter of the pump shaft of approximately 1.5 to 2.0, preferably approximately 1.8. In addition, the bearing bush of the plain bearing should be designed to be removable. The slide bearing is advantageously arranged behind the heat barrier, seen from the impeller, which contributes to a simple fastening possibility and 5 to an inexpensive design of the heat barrier.

In order to achieve a low heat conduction from the volute casing to the sealing chamber, a small cross-section and a large length of the pipe D section of the housing cover, which is designed as a heat barrier, has proven to be advantageous. This can be achieved particularly well with the specified bearing arrangement.

Due to the positioning of the bearing on the impeller side behind the heat barrier, the fluid used as the lubricant has a lower temperature at this point than in the pump housing. This makes it more viscous which is advantageous for the lubricity. In addition, the vapor pressure of the medium at this point is significantly lower than in the pump housing, which minimizes the risk of dry running in the warehouse.

It has proven to be advantageous to enclose the slide bearing or its bearing bush on the outside, for example in the long center thereof, with a clamping or tolerance ring which engages in the bearing cup. The width of the clamping or tolerance ring should correspond to a fraction of the length of the bearing bush, for example one fifth to one sixth of the length of the bearing bush. '' This results in simple (dis) assembly and compensation of misalignments due to tilting mobility.

There are several configurations of the plain bearing within the scope of the invention. In one case, the plain bearing contains an inner bearing sleeve, which is surrounded by a bearing bush so as to be suitable for bearing cups. Here, the pump shaft is encompassed within the slide bearing by at least one tolerance ring which engages in the pump shaft. In particular, on both sides of the outer tolerance ring, which engages in the bearing cup, as seen in the longitudinal section of the centrifugal pump, there should be an inner tolerance ring in each case, which engages in the pump shaft. Bearing sleeve and bushing are preferably made of silicon carbide.

Another concept according to the invention includes a plain bearing with a bearing bush so that it contains a sliding inner jacket that surrounds the pump shaft. The removable slide bearing bush is preferably made with an inner carbon coating. The bush runs on a hardened shaft or a hardened shaft part. The attachment is done by a - already mentioned - centrally located outer tolerance ring. According to a further feature of the invention, the mechanical seal comprises a shaft-side shaft sleeve, between which and the pump shaft at least one O-ring is provided. This enables the assembly of a mechanical seal in the unloaded version from the impeller side, which is particularly advantageous when the shaft is designed as a stub shaft.

According to another feature of the invention, a rear shaft bearing for the pump shaft is arranged in the housing approach at an axial distance from the mechanical seal outside the sealing space; at least one cavity can also be arranged in the housing attachment between the sealing space and the shaft bearing.

In a special shape, the pump shaft is designed as a stub shaft with a clamping ring.

Thanks to the different designs of the plain bearings described in combination with the three types

• Pump with base plate and coupling;

• Pump in block design;

• Pump in inline design

at least six variants of the centrifugal pump according to the invention.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

1, in each case an oblique view of different versions of a centrifugal pump according to the invention for heat transfer media;

FIG. 2: an end view of FIG. 1;

Fig. A partial longitudinal section through Figure 2 along the line III-III.

Figure 4 shows the enlarged longitudinal section through the pump of Figure 2 along the line IV-IV.

Fig. An enlarged section of Fig. 4;

4 shows the longitudinal section corresponding to FIG. 4 through another embodiment of the pump according to FIG. 1;

FIG. 7 shows an enlarged detail from FIG. 6;

FIG. 9: an end view of FIG. 8;

10 shows an oblique view of a housing cover of the pump;

11 shows the enlarged longitudinal section through the pump of FIGS. 8, 9 according to line XI-XI of FIG. 9; FIG. 12: a partial longitudinal section on line XII-XII in FIG. 9, enlarged compared to FIG. 11;

13, 14 different oblique views of part of a further embodiment of a centrifugal pump according to the invention;

D FIG. 15 is an end view of FIGS. 13, 14;

16: a partial longitudinal section through the pump of FIGS. 13 to 15 along line XVI-XVI in FIG. 15; 5

FIG. 17 shows a partial section through this pump according to line XVII-XVII in FIG. 15, enlarged in comparison with FIG. 16.

D A spiral housing centrifugal pump 10 has, on a spiral housing 14 equipped with connecting flanges 12, 12 _a , with the interposition of seals which are not identified, a bearing support housing 16 which contains a housing cover 18 with a housing attachment 34 attached to it.

The housing cover 18 is equipped with an annular flange 21 which projects from a bowl-like base region 20 and is penetrated by connecting screws 24 on a molded front ring 22 which forms a stop step; These are inserted in - axially parallel on the outside of a peripheral wall 13 of the spiral housing 14 formed over the shell wall 19 and connect the housing cover 18 to the spiral housing 14 in a centering manner. Shaped to the housing cover 18 or its base region 20 are axial ribs E which are determined by axial ribs E which penetrate radially through the longitudinal axis A of the pump and which are inclined to the longitudinal axis A of the pump at an angle w of approximately 40 ° and have a constant thickness b whose cross-sectional height h increases continuously in the longitudinal direction or in the axial direction away from the housing cover 18 and the other end is cast on a bearing pot 28 axially assigned to that longitudinal axis A of the pump or on a peripheral ring 30 surrounding the latter. The bearing pot 28 connects with the housing cover 18 in the center of an axial pipe section 32 which is integral with it. The bearing pot 28 with its edge ring 30 and the - here four - ribs 26 is part of the housing cover 18, the length of which a_ about a third of the pumps - 5 corresponds to long a.

The housing cover 18 and the rear-like housing extension 34 - that is to say the bearing bracket 16 - are penetrated by a pump shaft 36 of diameter d, on the front D stepped end 37 of which an impeller 40 is held by a nut 38. This impeller 40 rotates in the spiral housing 14, which contains a suction chamber 42, the inlet of which in the region of the axial connecting flange 12 is designated by 43 and the radial outlet of which in the connecting flange 12 _{a is designated} by 44 5. Near the impeller 40 there is a stuffing box packing 46 at the beginning of the cylindrical tube section 32 in the housing cover 18. The interior 29 of the bearing pot 0 28 connects to the cylindrical tube section 32, which includes the pump shaft 36 to form a heat barrier. If, for example, low-viscosity fluid enters through the inlet 43 at approximately 350 ° C., the interior of the storage pot has a high-viscosity fluid at 130 ° C. The inner space 29 of the bearing pot 28 adjoining the cylindrical tube section 32 opens into a sealing space 48, which is arranged in the bearing support housing 16 or in the housing extension 34, which is surrounded by an annular wall 50 and 5 with at least one locking screw 52 including this, in one Angle z of 45 ° to the longitudinal axis A of the pump inclined thread opening 53 and with - each having an axially parallel edge 54 - mutually inclined blade-like flat elements 55 is provided and the latter

ID axial length ei corresponds to approximately half the length e of the housing extension 34. A floor-like outlet screw 52 _b is arranged in a radial breakthrough in the floor area. In addition, Fig. 2 shows a side screw 52 _a , the 10 m when using the pump

15 vertical position is required for ventilation. A rear axial mechanical seal 56, which is not relieved, can be seen in the sealing space 48.

From the ring wall 50 four radial brackets 51 protrude, which 50 are connected to corresponding counter brackets 51 _{a of} that edge ring 30 by screws 24 _a . In versions not shown - especially large dimensions - an annular flange can be formed instead of the radial tabs 51 mentioned. In order to enlarge the surface of the outside of the ring S5 wall, axially extending flat pieces can be arranged outside the ring wall.

The mechanical seal 56 contains a - against a ring 38 pushed onto the pump shaft 36 or against a ring -

30 stage supporting - coil spring 58, which loads a rotating slide ring 59, which forms a sealing gap with a stationary counter ring 60. This counter ring 60 is located in the tube space 62 of an axial shaped connection piece 64 of the axial length f, which here is approximately half the sealing space

35 long egg corresponds. A bowl-like cavity 66 is arranged downstream of the ring base 65 of this molded connector 64 in the housing extension 34. Between this and the neighboring, stepped shaft end 37 _e surrounds the pump shaft 36 a deep groove ball bearing 68 with spacers 69 and a locking ring 70; this assembly covers a bearing cover 72 of the housing attachment 34. Below this, a shield-like support foot 74, which is fixed with screws 24 _b, protrudes radially from an angled plate which, in the area of the spiral housing 14 _{, is} opposite two stands 74 _{a which} project eccentrically in parallel. These and the support foot 74 are connected at the other end to a base plate, not shown.

3 to 5, a front hydrodynamic slide bearing 76 is arranged from a bearing bush 77 of length g with an inner jacket 78 made of carbon material in the interior 29 of the bearing pot 28; this slide bearing 76 surrounds in its longitudinal center a clamping or tolerance ring 80 of width n provided in the bearing pot 28, ie on the house side; This is elastic and connects the slide bearing 76 to the bearing pot in a force-locking manner.

. The slide bearing 76 _a of the pump 10 _a to Figures 6, 7 has a coaxial Lagerhulse 82 and within the bearing sleeve 77 - in addition to the already described outer tolerance ring 80 in cross-center - two shaft-side inner tolerance ranzringe 80 _x the width of i, the - seen in longitudinal section - flank that outer tolerance ring 80 on the pump shaft 36 on both sides at a radial distance. The width n of the outer tolerance ring 80 and the width i of the inner tolerance rings 80 _x are relatively short in relation to the length g of the bearing bush, for example the latter corresponds approximately to five to six times that width i or n.

At 84, a groove nut for fixing the bearing sleeve 82 is shown in FIGS. 6, 7 between the front slide bearing 76 _a and the rear - here relieved - sliding ring seal 56. The slide ring components for In the selected exemplary embodiment, absorption of the radial forces that occur preferably consist of silicon carbide.

The two types of bearings 76, 76 _a discussed can also be used in the 5 centrifugal pump 11 according to FIGS. 8 to 12, in which the pump shaft 35 is designed as a stub shaft and is equipped with an O-ring 88 within a shaft sleeve 86 of the mechanical seal 56 _a surrounding it is. This lies between the pump shaft 35 and a shaft sleeve 89 encompassing it ID.

At the rear end of the bearing bracket 16, the pump shaft 35 contains a tensioning ring 92 - which carries an air wheel 90 - and which is surrounded by a protective grille 93 as 15 poke protection. The tail-like - located in the engine - shaft bearing is not visible in the drawing.

The air wheel 90 is a wall ring 94 - with perforated sheets 95 - a lantern 96 with end flange

5D gen 97, 97 _a surround; these are connected by axially parallel longitudinal ribs 98. The flange ring 97 on the right in the drawing is screwed to a parallel flange ring 99 of a motor 100 which abuts the spiral housing 14; the latter is attached to the pump 11 by means of the lantern 96

25 times.

In the embodiment of a centrifugal pump ll _a vertical shaft 35 of FIG. 13ff are inlet 43 and outlet 44 of the Spiralgehauses 14 Q. on a diametral line and 3D this pump ll _a can with both of the bearing forms 76 described are bestuckt 76 _a.

Claims

PATENT CLAIMS

1. centrifugal pump, in particular spiral-housing centrifugal pump 5 for a heat transfer medium, with a spiral housing (14) having an impeller (40), a housing cover (18) and an associated housing extension (34) for a pump shaft (35, 36, 36 _a ), which is equipped with a shaft bearing (76, 76 _a ) close to the spiral housing (14) and with a shaft seal (56) attached to it in a sealing space (48) at a distance from it,

characterized,

5 that a bearing pot (28) receiving the shaft bearing (76, 76 _a ), a pipe section (32) surrounding the pump shaft (35, 36, 36 _a ) as a heat barrier and stand ribs (26) or spaced apart in the circumferential direction. Like. Profile elements are parts of the housing-D ceiling (18).

2. Centrifugal pump according to claim 1, characterized in that the bearing pot (28) to the impeller (40) by the pump shaft (35, 36, 36 _a ) surrounding pipe section 5 (32) is held at an axial distance.

3. Centrifugal pump according to claim 1 or 2, characterized in that attached to the housing cover (18) or one of its stand ribs (26) edge ring (30) D attached housing extension (34) the sealing space (48) for the shaft seal (56 ) limited.

4. Centrifugal pump according to claim 3, characterized in that the stand ribs (26) at their base region 5 (20) of the housing cover (18) distal ends are connected by the pump longitudinal axis (A) surrounding edge ring (30).

5. Centrifugal pump according to one of claims 1 to 4, characterized in that the stator ribs (26) at an angle (w) with the longitudinal axis (A) of the base-

5 rich (20) of the housing cover (18) to the shaft seal (56) are inclined.

6. Centrifugal pump according to claim 5, characterized by an angle (w) of 30 ° to 60 °. 0

7. Centrifugal pump after one of ... the. Claims 1 to 6, characterized in that the cross-sectional height (h) of the stator ribs (26), which preferably extend radially through the axial axis (A) of the pump, increases towards the mechanical seal (56).

8. Centrifugal pump according to one of claims 1 to 7, characterized in that the sealing space (48) borders on the shaft bearing (76, 76 _a ). 0

9. Centrifugal pump according to one of claims 1 to 8, characterized in that at least one stop stage (22) directed away from the spiral housing (24) for a further pump part (96) is arranged on the housing cover (18) 5.

10. Centrifugal pump according to claim 9, characterized in that the stop step is a front ring (22) formed onto the housing cover (18). D

11. Centrifugal pump according to claim 9 or 10, characterized in that the stop step or the front ring (22) of one of the stator ribs (26) surrounding, at their transition to a base region (20) of the housing 5 cover ice (18) attached ring flange (21) protrudes.

12. Centrifugal pump with a sealing ring (59) designed as a mechanical seal (56) shaft seal, which rotates on a counter ring (60) provided on the house, according to one of claims 1 to 11, thereby

5 characterized in that the mating ring (60) for the sealing ring (59) is arranged in a molded socket (64) of the housing extension (34) projecting axially into the sealing space (48) and the molded socket has at least one opening inclined to the longitudinal axis (A) of the pump (53) with him 10 closing screw (52) is assigned.

13. Centrifugal pump according to claim 12, characterized by an angle (z) between the longitudinal pump axis (A) and the longitudinal axis (B) of the opening (53) of approximately

15 45 °.

14. Centrifugal pump according to claim 12 or 13, characterized by an axial length (f) of the shaped piece (64), which is approximately half the axial length (egg) of the sealing space

SD (48) corresponds.

15. Centrifugal pump according to one of claims 1 to 14, characterized in that the shaft bearing is designed as a slide bearing (76) with a ratio of the length (g)

55 of the bearing bush (77) to the diameter (d) of the pump shaft (35, 36, 36 _a ) from about 1.5 to 2.0, preferably about 1.8.

16. Centrifugal pump according to claim 15, characterized in that the bearing bush (77) of the plain bearing (76, 76 _a ) is designed to be removable.

17. Centrifugal pump according to claim 15 or 16, characterized in that the plain bearing (76, 76 _a ) or its 5 bearing bush (77) is encompassed approximately in the long center outside of it by a clamping or tolerance ring (80) which is in the bearing pot (28) engages.

18. Centrifugal pump according to claim 17, characterized in that the width (s) of the clamping or tolerance ring (80) corresponds to a fraction of the length (g) of the bearing bush (77).

19. Centrifugal pump according to claim 18, characterized in that the width (s) of the outside clamping or tolerance ring (80) corresponds to about a fifth to a sixth of the length (g) of the bearing bush (77).

20. Centrifugal pump according to one of claims 15 to 19, characterized in that the slide bearing (76 _a ) contains an inner bearing sleeve (82) which is surrounded by a bearing cup-type bearing bush (77) (Fig. 6, 7).

21. Centrifugal pump according to one of claims 15 to 20, characterized in that within the slide bearing (76 _a ) the pump shaft (35, 36 _a ) is encompassed by at least one tolerance ring (80;, _. ) Which engages in the pump shaft.

22. Centrifugal pump according to one of claims 17 to 21, characterized in that on both sides of the outer

Tolerance ring (80), seen in the longitudinal section of the centrifugal pump (10 _a ), there is an inside tolerance ring (δOi) which engages in the pump shaft (35, 36 _a ).

23. Centrifugal pump according to one of claims 15 to 19, characterized in that the slide bearing (76) contains a bearing sleeve-side bearing bush (77) with the pump shaft (36) comprising a slidable inner jacket (78).

24. Centrifugal pump according to claim 23, characterized by an inner jacket (78) of the plain bearing (76) made of coal (Fig. 4, 5).

5 25. Centrifugal pump according to claim 23 or 24, characterized by a hardened pump shaft (36) or a corresponding shaft section associated with the bearing bush (77).

26. Centrifugal pump according to one of claims 1 to 25, characterized in that the mechanical seal (56) comprises a shaft sleeve (89) on the shaft side, between which and the pump shaft (36, 36 _a ) at least one O-ring (88) is provided , 5

27. Centrifugal pump according to one of claims 1 to 26, characterized in that in the housing extension (34) at an axial distance from the mechanical seal (56) outside the sealing space (48) a rear shaft bearing (68) for D the pump shaft (36, 36 _a ) is arranged.

28. Centrifugal pump according to claim 27, characterized in that at least one cavity 5 (66) is arranged between the sealing space (48) and the shaft bearing (68) in the housing extension (34).

29. Centrifugal pump according to one of claims 1 to 28, characterized in that the pump shaft (36 _a ) is designed as a stub shaft with a clamping ring (92). 0

30. Centrifugal pump according to one of claims 8 to 29, characterized in that the spiral housing (14) and the bearing support housing (16) from a to the stop stage / s or the front ring (22) struck lantern 5 (96) and this an engine (100) is attached.