US20170204855A1

US20170204855A1 - Rotating Pump and Securing Plate

Info

Publication number: US20170204855A1
Application number: US15/410,204
Authority: US
Inventors: Torben Hahn; Rene Linck; Benjamin Steinig
Original assignee: Fristam Pumpen Schaumburg GmbH
Current assignee: Fristam Pumpen Schaumburg GmbH
Priority date: 2016-01-20
Filing date: 2017-01-19
Publication date: 2017-07-20
Also published as: EP3214311B1; DK3214311T3; CN106989015B; DE102016100959A1; EP3214311A1; CN106989015A

Abstract

In a rotating pump having at least one driven conveying element which is arranged in a product space, flowed through by the product to be conveyed, and is driven by means of a shaft which protrudes into the product space from the outside, the shaft being sealed with respect to a wall of the product space, the seal is configured as a slide ring seal to be mounted on the product side with an outer positively locking positional securing means.

Description

CLAIM OF PRIORITY

The present application claims the benefit of the filing date of German Patent Application No. DE 10 2016 100 959.8, filed on Jan. 20, 2016, which is hereby incorporated by reference in its entirety.

FIELD

In general, the present teachings relate to a rotating pump, and more particularly to a rotating pump having at least one driven conveying element arranged in a product space, with the pump driven by a shaft that is sealed with respect to a wall of the product space.

BACKGROUND

A known measure for sealing the shaft with respect to the wall is, for example, the use of shaft sealing rings. However, they are only partially reliable and are not suitable, in particular, when the type of product to be conveyed requires a particularly secure seal, such as when conveying poisonous materials or in the hygienic field, for example in the food and/or cosmetic industry,
In the said fields, the use of slide ring seals which ensure a very satisfactory sealing action has become established. This is achieved, however, by way of a complex construction of the seal. As a rule, the seal has at least one rotating section which is connected to the shaft and one stationary section which is mounted in the wall.
For reliable functioning of the seal, the stationary section has to be secured axially and against rotation. The axial fixation has to prevent movement of the seal towards the product space, as otherwise functioning of the seal would be impaired in case of a vacuum condition in the product space. To this end, the said section usually has a flange or a seat which are fixed in the wall in a non-positive and/or positively locking manner, for example by way of screwing using a plurality of bolts or by way of shrink-fitting.
In many cases, in particular in the case of pumps for hygienic products such as foodstuffs or cosmetics, it is not desired or it is simply not possible to arrange a flange or a seat in the product space, since the product flow is impaired as a result and the corresponding contours are difficult to clean. Therefore, the flange has to be mounted from outside the product space. This is disadvantageous for various reasons.
In order to mount the flange, the shaft has to be pulled completely out of the product space. In the case of many pumps, this requires a complete separation of the product space and the pump drive. Since, at the same time, the mounting of the rotating section of the slide ring seal can take place only from the product side, the replacement or the maintenance of the seal is very complicated. In addition, in the case of the combination of the product space with a mounted stationary section of the seal and the pump drive, there is the risk that the seal is damaged as a result of uncontrolled contact with the shaft.
Therefore, what is needed is a pump, or constructing thereof, with increased reliability; suitability for use when conveying poisonous materials or in the hygienic field; arrangement of a flange or a seat in the product space; easier cleaning of contours within the product space; simplification of replacement or maintenance of seals within the pump; improved construction of the pump; or a combination thereof.

SUMMARY

The object therefore arises of improving the construction of pumps, in particular with regard to the abovementioned problems.
According to one aspect of the invention, this object is achieved by way of a rotating pump having at least one driven conveying element which is arranged in a product space, flowed through by the product to be conveyed, and is driven by means of a shaft which protrudes into the product space from the outside, the shaft being sealed with respect to a wall of the product space, characterized in that the seal is configured as a slide ring seal to be mounted on the product side with an outer positively locking positional securing means. Here, within the context of the invention, outer is to be understood to mean that the positional securing of the slide ring seal is brought about outside the product space.
Assembly and maintenance of the seal are substantially simplified by way of the proposed construction. The seal can be inserted into the wall from the product space via the shaft without separation of the product space and the pump drive.
For a particularly high quality sealing action, according to one refinement of the invention, the slide ring seal has a first rotating section, a second rotating section and a stationary section. According to one preferred development of the invention, the stationary section comprises a sleeve which is inserted into a seal seat in the wall.
If, according to a further embodiment of the invention, the sleeve protrudes out of the wall on the side which faces away from the product space, the positional securing means can be of particularly simple design. For this purpose, according to one embodiment, the sleeve has a circumferential groove on the section which protrudes out of the wall.
According to a further preferred embodiment of the invention, the positional securing means is configured as a securing plate which engages laterally around the sleeve and in the process engages into the groove. As a result, an axial movement of the sleeve in the seal seat is prevented reliably and in a simple way.
For a particularly effective securing action, the securing plate engages into the groove on a circumferential angle of more than 180°. To this end, the securing plate preferably has lateral fingers which, when engaging around the sleeve, are first of all bent outwards elastically and subsequently spring back in the direction of their rest position.
In one development of the invention, the sleeve has a milled-out section which adjoins the groove. The securing plate preferably has a projection which engages as an anti-rotation safeguard into the milled-out section. As a result of this refinement, the securing plate at the same time fulfils a function as an axial securing means and as an anti-rotation safeguard for the sleeve.
According to one development of the invention, the securing plate is arranged in a leakage space between the product space and a drive section of the pump, and the securing plate is bent over at an end which does not interact with the sleeve, in order to provide a protective hand guard for the leakage space.
The securing plate is preferably fixed by way of one or more securing bolts.
According to a further aspect of the invention, furthermore, the object is achieved by way of a securing plate of a pump, which securing plate is designed in accordance with the abovementioned embodiments. Reference is made expressly to the preceding explanations with regard to the advantages and effects of the securing plate according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pump in a perspective illustration.

FIG. 2 shows a horizontal sectional illustration of a pump in accordance with FIG. 1

FIG. 3 shows a vertical sectional illustration of a pump in accordance with FIG. 1.

FIG. 4 shows a horizontal section through the seal of the product section of a pump in accordance with one aspect of the invention.

FIG. 5 shows a securing plate of a pump in accordance with a further aspect of the invention.

DETAILED DESCRIPTION

As required, details of the present teachings are disclosed herein; however, it is to be understood that the disclosed teachings are merely exemplary, and the teachings may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present teachings.
The present teachings relate to a rotating pump having at least one driven conveying element which is arranged in a product space, flowed through by the product to be conveyed, and is driven by means of a shaft which protrudes into the product space from the outside, the shaft being sealed with respect to a wall of the product space. Pumps of corresponding construction are known both as flow pumps and positive displacement pumps.
FIG. 1 shows a pump 1 in a perspective illustration, which pump 1 includes or consists substantially of a drive section 2 and a product section 3. In the example which is shown, this is a hygienic single-flow screw-spindle pump, though the teachings are not limited to such a pump.
The drive section 2 of the pump 1 has a drive shaft journal 4, by way of which the pump 1 can be coupled to a drive motor (not shown). The product section 3 of the pump 1 has a product inlet 5 and a product outlet 6.. In the case of reversible operation of the pump 1, the product inlet 5 and the product outlet 6 can be swapped here in a manner which is dependent on the conveying direction.
The inner construction of the pump 1 is shown in FIGS. 2 and 3. In the product section 3, two displacing screws 7, 8 which engage into one another are arranged as conveying elements which are driven by two parallel shafts 9, 10. The displacing screws 7, 8 are plugged onto the shafts 9, 10 and are fastened releasably to the latter in a positively locking manner, by means of the fittings 11, 12 in the example which is shown.
The shafts 9, 10 extend out of the product section 3 into the drive section 2, where they are first of all mounted by way of radially acting needle bearings 13, 14 and by way of radially and axially acting angular contact ball bearings 15, 16. In the example which is shown, the angular contact ball bearings 15, 16 consist of in each case three bearings which are arranged behind one another and are described as one bearing for the sake of clarity, though a bearing arrangement having more or fewer bearings is also contemplated. The angular contact ball bearings 15, 16 include an inner ring 32, 33; balls 44, 45; and outer rings 26, 27. A synchronizing gear mechanism 17 with pinions 18, 19 which mesh in one another is arranged between the bearings 13, 14, 15, and 16. The synchronizing gear mechanism 17 transmits the movement which is imparted into the shaft 10 via the drive shaft journal 4 to the shaft 9, with the result that the displacing screws 7 and 8 rotate synchronously in opposite directions.
Particularly high requirements are to be made of the bearings 13, 14, 15, 16 and the synchronizing gear mechanism 17 of a single-flow screw-spindle pump 1. The displacing screws 7, 8 engage into one another with a minimum gap without contact, in order to achieve a high degree of efficiency. In order to avoid contact of the displacing screws 7, 8, by way of which contact they can be destroyed, the synchronizing gear mechanism 17 and the bearing system therefore have to be extremely rigid and low in play. In addition, in particular at high conveying rates and in the case of highly viscous or pasty products, high axial forces act on the shafts 9, 10 as a result of the single-flow construction, which axial forces have to be absorbed by the angular contact ball bearings 15, 16.
In order for it to be possible to withstand the high loads, the bearings 13, 14, 15, 16 have to be cooled continuously. To this end, an oil bath 20 is provided in the drive section 2 of the pump 1. Here, the pinions 18, 19 dip into an oil sump and produce an oil mist in the drive section 2, which oil mist enters into the bearings 13, 14, 15, 16 and at the same time lubricates and cools them.
The shafts 9, 10 are sealed at the product-side end of the drive section 2 by way of shaft sealing rings 21, 22, in order to prevent an exit of oil out of the drive section 2. A further shaft sealing ring 23 is provided for sealing the drive shaft journal 4.
During the assembly of the pump 1, the difficulty arises that the diameter of the pinions 18, 19 is greater owing to their function than the axial spacing of the shafts 9, 10, whereas the diameter of the seat bores 24, 25 for the outer rings 26, 27 of the angular contact ball bearings 15, 16 has to be smaller than the axial spacing of the shafts 9, 10. Therefore, the shafts 9, 10 cannot be introduced with mounted pinions 18, 19 through the seat bores 24, 25 into the drive section 2 of the pump 1.
The assembly therefore takes place as follows: before assembly, the inner rings 28, 29 of the needle bearings 13, 14, supporting bodies 30, 31 for the pinions 18, 19, and the angular contact ball bearings 15, 16 are mounted onto the shafts 9, 10. To this end, the inner rings 28, 29 of the needle bearings 13, 14 and the angular contact ball bearings 15, 16 are shrink-fitted onto the shafts 9, 10, whereas the supporting bodies 30, 31 are fixed on the shafts 9, 10 by way of feather key connections (not shown).
In the housing 34 of the drive section 2, the outer rings 35, 36 of needle bearings 13, 14 are fixed with the associated needle cages 41, 42 n corresponding seat bores 37, 38.
The parts 28, 29, 30, 31, 15, 16 which are mounted on the shaft 9, 10 are dimensioned in such a way that their external diameters are all smaller than the axial spacing of the shafts 9, 10, with the result that the preassembled shafts can be pushed through the seat bores 24, 25 into the drive section 2 in the direction of the product section 3. Here, the toothed rims 39, 40 are guided through an assembly opening 43 of the housing while being pushed over the shafts 9, 10.
One or more fixing plates 46 is/are then screwed on for axial fixing of the shafts 9, 10 and the angular contact ball bearings 15 16.
After the shafts 9, 10 are mounted in an axially play-free manner by way of fixing of the angular contact ball bearings 15, 16, the synchronizing gear mechanism 17 is finally assembled in the next step. To this end, the toothed rims 39, 40 which have already been laid loosely over the shafts 9, 10 while the latter were being pushed in are pushed onto the supporting bodies 30, 31, where they are seated with a tight fit and mesh with one another. To this end, the supporting bodies 30, 31 have stop shoulders 47, 48 on the side which faces away from the product section 3. Clamping plates 49, 50, 51, 52 are then placed against the toothed rims 39, 40 from the side which faces the product section 3. The clamping plates 49, 50, 51, 52 are in each case of approximately half-annular configuration and have end-side steps, with the result that in each case two clamping plates can be assembled to form one flush ring. The assembled rings are then fastened to the supporting bodies 30, 31 by means of bolts and press the toothed rims 39, 40 against the stop shoulders 47, 48, as a result of which they are fixed in a non-positive manner.
Production with very low play is possible by virtue of the fact that the seat bores 24, 25 of the angular contact ball bearings 15, 16 and the seat bores 37, 38 of the needle bearings 13, 14 can be made coaxially in the housing 34 which is manufactured in one piece, the risk of a radial offset of the individual seat bores 24, 25, 37, 38 with respect to one another being reduced, in particular.
The drive section 2 of the pump is adjoined by the product section 3 which is constructed from an intermediate flange 53 with a product inlet 5, a conveyor housing 54 and a closing flange 55 with a product outlet 6. The intermediate flange 53 is supported by way of an attachment collar 56 on the housing 34 of the drive section 2, with the result that a leakage space 58 is formed between it and the one drive-side wall 57. The said leakage space 58 ensures that oil from the drive section 2 can exit from the pump if one of the shaft sealing rings 21, 22 fails, without contaminating the conveyed product, which is of elementary significance, in particular, in the use of the pump in the hygienic field, such as in the food or cosmetic industry.
The shafts 9, 10 protrude into the product region through seal seats 59, 60 in the wall 57 and are sealed during the passage through the wall 57 by way of slide ring seals 61, 62, the location of which are generally pointed to in FIGS. 2 and 3. The construction of the said seals will be explained in greater detail in the following text using FIG. 4.
The slide ring seals 61 62 are of identical construction, for which reason only the slide ring seal 61 will be described here. All specifications also apply likewise to the slide ring seal 62.
The slide ring seal 61 is constructed in two stages and therefore has a stationary section 63 and two rotating sections 64, 65. The first rotating section 64 is seated on the drive side on the shaft 9 and is held axially and rotationally by way of pins 66, 67 which are screwed into the shaft 9. The stationary section 63 includes two sliding rings 68, 69 which are supported on one another by way of a spring ring 70. The unit comprising the two sliding rings 68, 69 and the spring ring 70 is enclosed in a sleeve 71 which is inserted into the seal seat 59 and is supported axially here on a projection 72.
The second rotating section 65 in turn includes a sliding ring 73 which is surrounded in a pot 74 which is supported on a step 75 of the shaft 9 and is clamped fixedly there by way of the displacing screws 7. Drivers 76 are screwed into the pot 74, which drivers 76 prevent a rotation of the sliding ring 73 with respect to the pot 74.
The sliding ring 68 is pressed against the rotating section 64 and the sliding ring 69 is pressed against the sliding ring 73 by way of the force of the spring ring 70, as a result of which they bear tightly against one another and seal the product space 77 with respect to the leakage space 58 (see FIGS. 2 and 3). Here, in particular, the sliding rings 69 and 73 may be manufactured from product-compatible and low-wear material.
The intermediate space between the sliding rings 68, 69, 73 and the shaft 9 is flushed by way of a product-compatible liquid which can be, for example, distilled water. This serves to cool the sliding rings and to transport away product constituent parts which possibly pass between the sliding rings. Inward and outward transport of the liquid takes place via channels in the wall 57, which channels are not shown for the sake of clarity.
During operation of the pump 1, it can occur that a vacuum prevails in the product space 77. In order to prevent the sleeve 71 from being pressed into the product space 77 by way of the ambient pressure, as a result of which in the worst case contaminants can pass into the product, the sleeve 71 protrudes beyond the wall 57 on the drive side and has a circumferential groove 78 there. Fingers 79, 80 (FIG. 5) of a securing plate 81 which is pushed into the leakage space 58 from the outside engage into the said groove 78. As a result, the sleeve 71 is locked axially, with the result that it cannot be pressed into the product space. At one location, the groove 78 has an axial milled-out section 82 which interacts with the projection 83 of the securing plate 81, in order to secure the sleeve 71 against rotation.
The securing plate 81 is shown in greater detail in FIG. 5. The securing plate has two outer fingers 79, 80 and a middle web 84 which are adapted in terms of the contour to the groove bottom of the groove 78. Overall, they enclose an angle of about 180° or greater, with the result that, when the securing plate 81 is pushed in, the fingers 79, 80 are bent outwards elastically and then spring back into their starting position. The elastic deformation may be assisted by way of slots 85, 86 which engage over securing bolts 87 (FIG. 4) when the securing plate is pushed in. A small bracket 88 may be provided in the center of the web 84, which bracket 88 is used to form the projection 83. To this end, as shown in FIG. 4, a small plate 89 can be fastened on the bracket 88, for example by way of spot welding. As an alternative, the bracket 88 itself can be bent or beaded somewhat out of the plane of the securing plate 81, in order to form the projection 83.
At the free end of the securing plate 81, a narrow strip may be bent over by approximately 90°±about 10° and therefore acts as a protective hand guard 90 for the leakage space 58. A sufficient gap remains here, in order to tighten the securing bolts 87 by way of a spanner after the securing plate 81 is pushed in, and thus to fix the securing plate 81.
The mounting and dismantling of the slide ring seals 61, 62 is particularly simple and takes place from the product side with a dismantled closing flange 55.
The rotating section 64 is guided onto the shaft from the product side and is pushed as far as the pins 66, 67 which have already been screwed into threaded bores of the shaft 9, 10 before the mounting of the drive section 2. The stationary section 63 is then guided with the sliding rings 68, 69, the spring ring 70 and the sleeve 71 over the shaft 9 and is pushed as far as into the seal seat 59, the sleeve 71 protruding out of the wall 57 on the drive side as far as the circumferential groove 78. Next, the securing plate 81 is pushed into the leakage space 58, with the result that the fingers 79, 80 and the web 84 engage into the groove 78. Here, the sleeve is oriented in such a way that the projection 83 engages into the milled-out section 82 and thus secures the sleeve against rotation. After the securing plate has been pushed in completely, the securing bolts 87 are tightened, in order to fix the securing plate.
Finally, the rotating section 65 is pushed with the pot 74 and the sliding ring 73 onto the shaft 9 as far as the step 75. The slide ring seals 61, 62 are fixed by way of mounting of the displacing screws 7, 8.
During the mounting of the displacing screws 7, 8, they are preferably oriented with respect to one another before being pushed onto the shaft 9, 10, with the result that the corresponding thread turns engage into one another. The displacing screws 7, 8 and the product-side ends of the shaft 9, 10 have fitting elements of complementary shape, with the result that a rotation of the displacing screws 7, 8 on the shaft 9, 10 is ruled out. The positively locking connection is secured additionally by way of the fittings 11, 12.
Since the displacing screws 7, 8 can be placed on the shaft 9, 10 only in discrete angular positions as a result of the positively locking connection, it is necessary to rotate the shafts 9, 10 with respect to one another, in order to set an optimum contactless orientation of the displacing screws 7, 8 with respect to one another. This is important, in order to avoid premature wear of the displacing screws 7, 8.
To this end, the clamping plates 49, 50 for the toothed rim 39 are loosened somewhat through the assembly opening 43, with the result that the toothed rim 39 can rotate on the supporting body 30. The gap between the displacing screws 7, 8 is then set by way of rotation. In a correct position of the displacing screws 7, 8 with respect to one another, the clamping plates 49, 50 are tightened again, with the result that the toothed rim 39 is fixed again such that it cannot rotate.
After the adjustment of the displacing screws 7, 8, the closing flange 55 is placed onto the conveyor housing. The assembly opening is closed by way of a cover 91 on the drive section 2 of the pump. The pump 1 is ready for use after this.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the teachings contemplated. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention. As can be appreciated, variations in the above teachings may be employed.
Unless otherwise stated, all ranges include both endpoints and all numbers between the endpoints. The use of “about” or “approximately” in connection with a range applies to both ends of the range. Thus, “about 20 to 30” is intended to cover “about 20 to about 30”, inclusive of at least the specified endpoints.
The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The term “consisting essentially of” to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, ingredients, components or steps herein also contemplates embodiments that consist essentially of, or even consisting of, the elements, ingredients, components or steps.
Plural elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step might be divided into separate plural elements, ingredients, components or steps. The disclosure of “a” or “one” to describe an element, ingredient, component or step is not intended to foreclose additional elements, ingredients, components or steps.
Relative positional relationships of elements depicted in the drawings are part of the teachings herein, even if not verbally described. Further, geometries shown in the drawings (though not intended to be limiting) are also within the scope of the teachings, even if not verbally described.

Claims

What is claimed is:

1. A rotating pump having at least one driven conveying element which is arranged in a product space, flowed through by a product to be conveyed, and is driven by means of a shaft which protrudes into the product space from outside, the shaft being sealed with respect to a wall of the product space, wherein the seal is configured as a slide ring seal to be mounted on the product side with an outer positively locking positional securing means, the positional securing means being configured to prevent both rotational movement of the slide ring seal and axial movement of the slide ring seal towards the product space.

2. The pump according to claim 1, wherein the slide ring seal has a first rotating section, a second rotating section and a stationary section.

3. The pump according to claim 2, wherein the stationary section comprises a sleeve which is inserted into a seal seat in the wall.

4. The pump according to claim 3, wherein the sleeve protrudes out of he wall on the side which faces away from the product space.

5. The pump according to claim 4, wherein the sleeve has a circumferential groove on the section which protrudes out of the wall.

6. The pump according to claim 5, wherein the positional securing means is configured as a securing plate which engages laterally around the sleeve and in the process engages into the groove.

7. The pump according to claim 6, wherein the securing plate engages into the groove on a circumferential angle of more than 180°.

8. The pump according to claim 6, wherein the securing plate has lateral fingers which, when engaging around the sleeve, are first of all bent outwards elastically and subsequently spring back in the direction of their rest position.

9. The pump according to claim 5, wherein the sleeve has a milled-out section which adjoins the groove.

10. The pump according to claim 6, wherein the sleeve has a milled-out section which adjoins the groove.

11. The pump according to claim 9, wherein the positional securing means is configured as a securing plate that has a projection which engages as an anti-rotation safeguard into the milled-out section.

12. The pump according to claim 10, wherein the securing plate has a projection which engages as an anti-rotation safeguard into the milled-out section

13. The pump according to claim 6, wherein the securing plate is arranged in a leakage space between the product space and a drive section of the pump, and in that the securing plate is bent over at an end which does not interact with the sleeve, in order to provide a protective hand guard for the leakage space.

14. The pump according to claim 6 wherein the securing plate is fixed by way of one or more securing bolts.

15. A securing plate of a pump according to claim 6, wherein the securing plate has a projection which is adapted to engage as an anti-rotation safeguard into a milled-out section of a sleeve inserted into a seal seat in a wall of a product space of the pump.

16. The securing plate of claim 15, wherein the securing plate has lateral fingers which, when engaging around the sleeve, are first bent outwards elastically and subsequently spring back in the direction of their rest position.

17. The securing plate of claim 15, wherein the securing plate is adapted to be arranged in a leakage space between the product space and a drive section of the pump.

18. The securing plate of claim 17, wherein the securing plate is bent over an end which does not interact with the sleeve to provide a protective hand guard for the leakage space.

19. The securing plate of claim 15, wherein the securing plate is adapted to be fixed by way of one or more securing bolts.