EP3029332B1 - Axially split pump - Google Patents

Description

The invention relates to an axially divided pump for conveying a fluid according to the preamble of the independent claim.

Axially split pumps, also referred to as horizontally split pumps, are pumps in which the housing is split parallel to the axis of the shaft and thus has a base and cover. Both the lower part and the lid each have a flange, which are stacked for mounting the pump and then firmly connected to each other, for example, screwed.

Axially split pumps have long been well known and in many embodiments are usually manufactured as centrifugal pumps, for example as single or double-flow pumps and as single-stage or multi-stage pumps. The impeller of the pump can be arranged between two bearings (Between-bearing pump). The range of application of these pumps is also very broad, they are used for example in the oil and gas industry or in the water industry or in the field of energy production. Frequently, axially split pumps are designed for high operating pressure or high flow rates and are suitable for pumping over large geodesic heights, for pumping through water or oil pipelines, or for seawater desalination using reverse osmosis.

In the case of axially split pumps, of course, the sealing between the lower part and the cover of the housing along the two flanges is of crucial importance. Likewise must between the housing and the Side covers, which close the pump in the axial direction, a very good seal can be achieved.

For sealing between the lower part and the lid, it is known, in particular for applications with high pressure, to insert a flat gasket between the two flanges, so that the two flanges do not touch each other directly in the mounted state, but contact the flat gasket on both sides. Such gaskets require a high bias, in particular, in order to achieve the required surface pressure between the lower part, the lid and the gasket.

An alternative technology for sealing between the lower part and the lid, as for example in the WO-A-2014/083374 is to mount the flanges of the base and the top directly to each other without intervening seal. The respective surfaces of the two flanges then form sealing surfaces, which have direct contact with each other in the mounted state. In this solution, a sealing groove is provided in the lower part or in the lid or in the lower part and in the cover, which extends over the entire axial length of the pump and in which a cord-shaped sealing element, for example, an O-ring-like sealing element is inserted. Most of these sealing groove is provided for manufacturing and assembly reasons only in the lower part. After inserting the cord-shaped sealing element in the sealing groove, the lower part and the cover are firmly screwed together so that the sealing surfaces of the two flanges are in direct contact with each other and the cord-shaped sealing element is elastically deformed in the sealing groove, so as to ensure a reliable seal.

Since in this solution, no flat gasket between the flange of the lower part and that of the lid is inserted, the glands, with which the lower part and the cover are fastened to each other, to bear a significantly lower load. This results in several advantages: Thus, the flanges, which form the sealing surfaces, are made significantly thinner and narrower, it is less material for the flanges needed, which brings a cost and a weight saving, for the Bolting the lower part and cover can be used smaller screws or bolts, these can therefore be placed closer to the hydraulic contour. In addition, the use of the cord-shaped sealing elements in comparison to the flat gaskets to a higher deformation of the housing. This is particularly advantageous in the case of multistage pumps because this significantly reduces or even prevents the leakage between different pressure chambers in the pump, in which different pressures prevail.

The cord-shaped sealing elements are usually made of an elastomer, as it is also used for commercial O-ring seals, for example, from the nitrile rubber nitrile-butadiene rubber (NBR: nitrile butadiene rubber).

In most applications, it has proven to be advantageous to provide more than one sealing groove, each with an inserted string-shaped sealing element. Thus, for example, an inner cord-shaped sealing element may be provided for sealing the suction chamber against the pressure chamber and an outer cord-shaped sealing element, which seals the interior of the pump against the outside world, so the ambient pressure. In particular, in multi-stage pumps additional sealing grooves can be provided, each with inserted string-shaped elements to distinguish the different pressure chambers, in which different pressures prevail against each other.

When designing such seals by means of cord-shaped sealing elements, it is endeavored to make the individual cord-shaped sealing elements as closed so particular annular sealing elements, because the connection or shock points between individual cord-shaped sealing elements can potentially lead to leaks, especially if the pump for a high operating pressure of, for example, up to 100 bar is designed. However, it is purely constructive not possible to provide exclusively self-contained sealing cords. It will always be such critical To provide places where two individual sealing elements adjoin one another and must cooperate for the desired sealing.

One such critical location is the connection between the housing of the pump and the side covers of the pump, a point at which a total of three components adjoin one another, namely the lower part of the housing, the cover of the housing and the side cover. At this critical point, the pump must be sealed against the environment or the ambient pressure. Leakages that occur here not only lead to a reduction in the efficiency of the pump, but can also lead to environmental stresses due to escaping fluid, for example in the case of liquids such as crude oil or crude oil, depending on the fluid delivered by the pump.

Furthermore, the deals JP S62 24079 Y2 especially with the sealing of the side cover in an axially split pump. Here it is the essential idea to insert into the contact surfaces of the upper and lower housing part, which in the assembled state, the side cover, two semicircular seals, but each end shortly before reaching the contact surface between the upper housing part and the lower housing part, itself so do not touch even in the assembled state. In the side cover an additional sealing element is provided, which covers the area that is not covered by the sealing elements. In the solution according to JP S62 24079 Y2 a direct contact between the semicircular seals, which seal the side covers, with the sealing element, which seals between the two housing parts, does not exist.

Starting from the described prior art, it is therefore an object of the invention to propose an axially divided pump for conveying a fluid, in which a reliable and high pressure-tight seal between the housing of the pump and the side cover is provided.

The object of the invention solving this object is characterized by the features of the independent claim.

Preferably, a cord-shaped sealing element is inserted into the sealing groove and inserted into the annular sealing groove an annular sealing element.

The invention is based on the finding that in particular at such contact points between two separate sealing elements, against which a planar -also non-curved end surface of a sealing element on a curved surface, for example, the lateral surface of a circular cross-section second sealing element. This geometry requires a reduced contact surface between the two sealing elements, so that leakages can occur here more easily.

Characterized in that according to the invention, the annular groove for receiving the annular sealing member is formed jointly by the housing and the side cover, arise at this critical point additional sealing points, through which the effect of the sealing elements is improved, so that especially at very high operating pressure an extremely reliable seal is ensured between the housing of the pump and the side cover.

For structural reasons, such an embodiment is preferred in which the cord-shaped sealing element has a planar cross-sectional area on the second contact surface.

For a good sealing effect, it is an advantageous measure if the sealing groove opens substantially perpendicularly into the annular groove.

According to a preferred embodiment, the sealing groove is provided in the lower part of the housing, which in particular allows for easier production and easier assembly.

Further, such a configuration is preferred in which the sealing groove extends from the second contact surface to the opposite end of the pump with respect to the axial direction, which is designed to receive a second side cover, which is suitable for closing the housing and in which the sealing groove, the cord-shaped sealing element is inserted, which extends over the entire longitudinal extent of the sealing groove. As a result, a continuous - so separated by connections separate sealing elements - sealing between the lower part and the cover of the housing along the entire axial length of the pump is guaranteed. Of course, this continuous seal groove is not rectilinear in the rule but follows suitably the inner contour in the pump.

In constructive aspects, it is an advantageous measure if the annular groove formed by the recess and the projection has a substantially rectangular cross-sectional area perpendicular to its longitudinal extent.

With regard to a good sealing effect, it is preferred if the annular groove has a width in the radial direction which is greater than the width of the cord-shaped sealing element.

With respect to the annular sealing element, it is preferred if in the annular groove an annular sealing element is inserted, which preferably has a circular or elliptical cross-sectional area.

It is particularly advantageous if the annular sealing element has a height in the axial direction, which is greater than the depth of the annular groove in the axial direction. As a result, the annular sealing element in the unassembled state protrudes beyond the annular groove with respect to the axial direction and is then pressed against the end face of the cord-shaped sealing element during assembly under elastic deformation, so that an intimate contact between the two sealing elements is ensured here.

A further advantageous measure consists in that the sealing groove has at its junction in the second contact surface a recess which is arranged radially inwardly with respect to the sealing groove.

In this recess can then optionally be inserted an elastic biasing element which exerts a radially outwardly directed bias on the cord-shaped sealing element. This measure has the advantage that even at lower operating pressures, so for example when starting the pump, a very good sealing effect is achieved from the beginning. Furthermore, there is the advantage that after prolonged service life of the pump, if degradation or other changes in the cord-shaped sealing element can occur, the elastic biasing element compensates for these changes and reliably presses the sealing element against the wall of the sealing groove.

Preferably, the biasing element is resilient and extends parallel to the cord-shaped sealing element. Particularly preferably, the biasing element is designed as a spring.

With respect to the material, it is preferred if the annular sealing element and the cord-shaped sealing element is made of an elastomer, in particular of a nitrile rubber, especially of nitrile-butadiene rubber (NBR).

The inventive pump is particularly suitable for very high operating pressures and can preferably be designed as a centrifugal pump with a design pressure of at least 50 bar, preferably at least 100 bar.

Further advantageous measures and embodiments of the invention will become apparent from the dependent claims.

Fig. 1:

ein perspektivische Darstellung eines Ausführungsbeispiels einer erfindungsgemässen Pumpe, wobei der Deckel entfernt und nur symbolisch angedeutet ist,

Fig.2:

eine Aufsicht auf das Unterteil des Gehäuses des Ausführungsbeispiels aus Fig. 1,

Fig. 3:

den Seitendeckel des Ausführungsbeispiels aus Fig. 1 sowie einen Teil des Gehäuses,

Fig. 4:

eine schematisierte Darstellung des Seitendeckels und des Gehäuses des Ausführungsbeispiels aus Fig. 1,

Fig. 5:

analog zu Fig. 4, aber mit eingelegten Dichtungselementen, und

Fig.6:

eine Variante für das Ausführungsbeispiel in einer zu Fig. 5 analogen Darstellung.

In the following the invention will be explained in more detail by means of embodiments and with reference to the drawing. In the drawing show, partly in section:

Fig. 1:

a perspective view of an embodiment of a pump according to the invention, wherein the lid is removed and indicated only symbolically,

Figure 2:

a plan view of the lower part of the housing of the embodiment Fig. 1 .

3:

the side cover of the embodiment Fig. 1 as well as a part of the housing,

4:

a schematic representation of the side cover and the housing of the embodiment Fig. 1 .

Fig. 5:

analogous to Fig. 4 but with inserted sealing elements, and

Figure 6:

a variant of the embodiment in a too Fig. 5 analog representation.

Fig. 1 shows a perspective view of an embodiment of an inventive axially divided pump, which is generally designated by the reference numeral 1. The pump 1 comprises a housing 2, which is divided axially, and a lower part 21 and a cover 22 includes. For better understanding is in Fig. 1 the lid 22 removed and indicated only symbolically. Fig. 2 shows a plan view of the lower part 21 of the housing 2 of this embodiment.

The housing 2 comprises an inlet 5 for sucking a fluid to be delivered and an outlet 6 for the fluid. Furthermore, the pump 1 comprises a rotatable shaft 3 whose longitudinal direction defines an axial direction A. On the shaft 3 is at least one impeller 4, in the present case, there are two wheels 4, rotatably mounted, which promotes the fluid from the inlet 5 to the outlet 6. Further, a bearing device 7 is provided at both ends with respect to the axial direction A of the pump 1 to support the shaft 3 of the pump 1. The representation according to left bearing device 7 ( Fig. 1 ) is further provided with a coupling 8 which is connectable to a drive, not shown, which causes the shaft 3 of the pump 1 in rotation.

The term axially divided pump 1 or axially split housing 2 means, as is generally customary, that the housing 2 is divided parallel to the longitudinal direction of the shaft 3, ie in a plane which contains the longitudinal axis of the shaft 3.

In particular, it is in the in the Fig. 1 and Fig. 2 illustrated pump 1 to an axially divided multi-stage - here two-stage centrifugal pump, which is designed einflutig and in a so-called Between-Bearing arrangement, ie the wheels 4 are located between the storage devices 7. It is understood that the invention is not limited to such pump types but is also suitable for all other pumps with axially split housing 1, for example, single-stage pumps, ie those with only one impeller 4, double-flow pumps with single-stage or multi-stage design or other types of pumps as centrifugal pumps.

With respect to the axial direction A, the housing 2 of the pump 1 is closed in each case by a side cover 9, which simultaneously constitutes the end cover of the mechanical shaft seal in the present case.

The cover 22 and the lower part 21 of the housing 2 are in direct contact with each other in the mounted state, that is, no flat gasket is provided between these two parts, which prevents direct contact between the lower part 21 and the cover 22. For this purpose, the lower part 21 comprises a first flange 211, which extends in the assembled state in the plane of the axial pitch of the housing 2 and whose upper surface according to the illustration forms a first sealing surface 212. In a similar manner, the cover 22 is provided with a second flange 221, which extends in the assembled state in the plane of the axial pitch of the housing 2 and its lower surface according to the representation ( Fig. 1 ) forms a second sealing surface 222.

After mounting the cover 22 on the lower part 21, the first sealing surface 212 and the second sealing surface 222 are in direct contact with each other to form a sealing connection between the lower part 21 and the cover 22 of the housing 2. In the first sealing surface 212 of the Lower part 21 is a sealing groove 213 is provided, which extends from the representation according to the left side cover 9 in the axial direction A of the inner contour of the pump 1 following up to the other side cover 9. This seal groove 213 is provided on both sides of the shaft 3. In the sealing groove 213, a cord-shaped sealing element 10 is inserted, which extends over the entire length of the sealing groove 213 and which seals the interior of the pump 1 from the environment. The cord-shaped sealing element 10 usually has a round cross-section, as it is known for example from commercially available O-rings. Of course, it is also possible that the cord-shaped sealing element has a different cross section, for example a rectangular and in particular a square cross section. In this case, the cord-shaped sealing element 10 is dimensioned with respect to its diameter so that it protrudes beyond the edge of the sealing groove 213 in the unassembled state. When mounting the cover 22 on the lower part 21 thus the cord-shaped sealing element 10 is elastically deformed and thus ensures a reliable seal between the lower part 21 and the cover 22 of the housing. 2

The attachment of the cover 22 on the lower part 21 is preferably carried out by means of bolts or screws, which by the provided in the first sealing surface 212 holes or tapped holes (without reference numerals in Fig. 1 and Fig. 2 ), so that the lower part 21 and the cover 22 are screwed tightly and sealingly together.

Alternatively, it is also possible to provide the sealing groove 213 in the cover 22 of the housing 2, or to provide a sealing groove both in the lower part 21 and in the cover 22. For manufacturing and assembly reasons, it is preferable to provide the sealing groove 213 or the sealing grooves only in the lower part 21.

For sealing between the side cover 9 and the housing 2, the side cover 9 has a first contact surface 91, which cooperates with a second contact surface 23 which is provided on the housing 2 (see Fig. 3 ). The second contact surface 23 surrounds the shaft 3 and extends both over the lower part 21 of the housing 2 and over the cover 22 of the housing 2. For a better understanding shows Fig. 3 in an enlarged view, the side cover 9 and a part of the housing 2 in a plan view of the lower part 21, wherein the side cover 9 is not yet joined to the housing 2. Evident is also the sealing groove 213 in the lower part 21 of the housing 2, which extends into the second contact surface 23 of the housing 2.

The sealing connection between the side cover 9 and the housing 2 is a particular challenge, because here three components adjoin one another, namely the side cover 9, the lower part 21 and the cover 22 of the housing 2. The first contact surface 91 of the side cover 9 is replaced by one of his Boundary surfaces formed in the axial direction A. The second contact surface 23 of the housing 2 is perpendicular to the axial direction A, so that it faces the first contact surface 91.

According to the invention, a recess 24 is provided in the second contact surface 23 of the housing 2, which recess is designed here as a central recess in the second contact surface 23. Further, in the first contact surface 91 of the side cover 9, a projection 92 is provided, which is designed here as a central elevation. The recess 24 and the projection 92 are designed and arranged to each other so that they together in the mounted state of the side cover 9 an annular groove 29 for receiving an annular sealing member 11 (see also Fig. 4 and Fig. 5 ) form.

For this purpose, in the embodiment described here, the central recess, which forms the recess 24 in the second contact surface 23, substantially formed with a circular cross-section whose diameter is greater than the diameter of the also formed substantially circular circular projection, which the projection 92nd forms in the first contact surface 91. This results only after the assembly of the side cover 9 and the housing 2, the jointly formed annular groove 29. This annular groove 29 is thus bounded radially outwardly by the side wall 241 of the recess 24 in the second contact surface 23 of the housing 2 and radially inwardly the lateral boundary surface 921 of the projection 92 in the first contact surface 91 of the side cover 9.

Fig. 4 shows in a schematic representation of the annular groove 29, which results from the composition of the side cover 9 and the housing 2. For a better overview are in Fig. 4 the annular sealing member 11 and the cord-shaped sealing member 10 is not shown. Further limited Fig. 4 on the illustration of the upper half of Fig. 3 because this is sufficient for understanding.

Fig. 5 is a representation similar to the one in Fig. 4 However, here are the annular sealing member 11 inserted into the annular groove 29 and the cord-shaped sealing member 10 in the seal groove 213.

By joining the side cover 9 and the housing 2 is formed by the interaction of the projection 92 in the side cover 9 and the recess 24 in the housing 2, the annular groove 29, which surrounds the shaft 3 of the pump 1. Within the area bounded by the annular groove 29, the first contact surface 92 and the second contact surface 23 are in direct contact with each other after mounting the side cover.

As this particular Fig. 4 illustrates, the annular groove 29 perpendicular to its longitudinal direction extending in the circumferential direction has a substantially rectangular cross-sectional area. This cross-sectional area is determined by the axial depth T of the annular groove 29 - ie its depth with respect to the axial direction A - and by the radial width B of the annular groove 29 - ie its width with respect to the radial direction perpendicular to the axial direction A.

Like also out Fig. 4 As can be seen, it is preferred that the sealing groove 213 opens substantially perpendicularly into the annular groove 29. Since the end face of the cord-shaped sealing element 10 placed on the second contact surface 23 is preferably a planar, ie non-curved, cross-sectional area (see FIG Fig. 5 ), By this measure, the best possible contact between the cord-shaped sealing element 10th and realize the annular seal member 11 in the annular groove 29.

It is also preferred if the radial width B of the annular groove 29 is greater than the width of the cord-shaped sealing element 10. The sealing groove 213 is then arranged so that it opens centrally into the annular groove 29.

The annular sealing element 11, which is inserted into the annular groove 29, preferably has a circular or elliptical cross-sectional area, so that commercial sealing elements such as O-rings can be used here. Of course, it is also possible that the annular sealing element has a different cross section, for example a rectangular and in particular a square cross section. The annular sealing element 11 is preferably dimensioned such that its height, which means its extent in the axial direction A, is greater than the axial depth T of the annular groove 29. Namely, the annular sealing element 11 protrudes in the unassembled state of the side cover 9 with respect to the axial direction A beyond the projection 92 of the first contact surface 91 out. When mounting the side cover 9 on the housing 2, consequently, the annular sealing member 11 is elastically deformed and in consequence in intimate contact with the end face of the cord-shaped sealing member 10 (see Fig. 5 ). With respect to the extent in the radial direction, the annular sealing element 11 is preferably dimensioned such that it fills the radial width B of the annular groove 29.

The cord-shaped sealing element 10 is preferably also an O-ring-like element, but not designed as a ring but as a cord with two ends, and an example circular or circular cross-sectional area perpendicular to its longitudinal extent. With respect to the width in the radial direction, the cord-shaped sealing member 10 is usually sized so that it does not completely fill the sealing groove 213, as in Fig. 5 is shown.

Suitable materials for both the annular sealing element 11 and the cord-shaped sealing element 10 are in particular all materials known per se, which are used for such seals, in particular elastomers such as nitrile rubber and especially nitrile-butadiene rubber (NBR).

With regard to the mounting of the pump 1, the procedure is, for example, as follows: The cord-shaped sealing element 10 is inserted into the sealing groove 213 provided in the lower part 21 of the housing 2 on both sides of the shaft 3 (see eg Fig. 2 ) so as to extend from the second contact surface 23 of the housing 2 along the axial direction A of the inner contour of the pump 1 following to the opposite axial end of the pump 1. Subsequently, the cover 22 of the housing 2 can be connected to the lower part 21, wherein the cord-shaped sealing element 10 in the sealing groove 213 preferably elastically deformed and contributes to the seal between the lower part 21 and the cover 22.

Before mounting the side cover 9, the annular seal member 11 is placed around the projection 92 in the side cover 9. After mounting the side cover 9 on the housing 2 then forms the annular groove 29, in which the annular sealing member 11 is inserted, which presses against the end face of the cord-shaped sealing member 10, which is inserted into the seal groove 213. This condition is in Fig. 5 shown.

The inventive embodiment with the annular groove 29, which is formed jointly by the projection 92 in the first contact surface 91 of the side cover 9 and the recess 24 in the second contact surface 23 of the housing 2, connects in a very advantageous manner with the effect of a mainly axial seal those of a mainly radial seal.

Like this Fig. 5 shows created by the common annular groove 29, whose one wall is formed by the side wall 241 of the recess 24, while the other wall is formed by the lateral boundary surface 921 of the projection 92, additional axial sealing surfaces 30 and additional radial sealing surfaces 31, which contribute to an improved seal between the housing 2 and the side cover 9.

This improved sealing effect is particularly advantageous with regard to the highest possible operating pressure of the pump 1. Thus, the pump 1 can be designed, for example in one embodiment as a centrifugal pump, with a design pressure of at least 50 bar and preferably at least 100 bar.

Fig. 6 illustrated in a too Fig. 5 a particularly preferred variant of the embodiment of the inventive pump 1. In the following, only the differences from the described embodiment will be discussed. Otherwise, the above explanations in the same or mutatis mutandis the same way apply to this variant. In particular, the reference numerals have the same meaning for the same or functionally equivalent parts.

At the in Fig. 6 illustrated variant, the seal groove 213 at its junction in the second contact surface 23 and in the annular groove 29 has a recess 214 which is arranged radially inwardly with respect to the seal groove 213. The recess 214 extends parallel to the sealing groove 213, such that the sealing groove 213 in its end region in the axial direction A over a length L has an enlarged by the width D of the recess 214 expansion in the radial direction. Like this Fig. 6 shows, the radially inner boundary surface 215 of the recess 214 is disposed so that it is closer to the shaft 3 than the lateral boundary surface 921 of the projection 92. Thereby exists between the lateral boundary surface 921 of the projection 92 and with respect to this radially inwardly arranged boundary surface 215th the recess 214 is a shoulder 216, which is part of the first contact surface 91 of the side cover 9.

In the recess 214, an elastic biasing element 217 is preferably inserted, which exerts a radially outwardly directed bias on the cord-shaped sealing element 10. Preferably, the biasing member 217 is resilient, and more preferably as a spring designed. The spring 217 extends parallel to the cord-shaped sealing element 10 and is dimensioned so that it is wider than the width D of the recess 214 with respect to the radial direction. After mounting the side cover 9, the spring 217 can be supported on the shoulder 216.

The variant with the biasing member 217 offers several advantages. During operation of the pump 1, the biasing element ensures an additional contribution, that even at lower operating pressures, so for example when starting the pump 1, immediately a sufficient sealing effect between the housing 2 and the side cover 9 is realized. Also with regard to the long-term operation of the pump 1, the biasing member 217 is advantageous. If it comes with increasing operating time of the pump 1 to degradation, fatigue or other changes or wear of the cord-shaped sealing member 10, these can be compensated by the action of the biasing member 217, because this the cord-shaped sealing member 10 reliably against the radially outer wall of the sealing groove 213rd suppressed.

As a further additional measure, in particular at very high operating pressures of the pump, it may be advantageous, in the region of the common annular groove 29 on the first or the second sealing surface 212 or 222 of the lower part 21 and the cover 22 before connection of the cover 22nd with the lower part 21 to apply a thin liquid seal, so a fluid that enhances the sealing effect between the two sealing surfaces 212 and 222.

Although the invention is explained only with further reference to one of the two side cover 9, it is understood, of course, that preferably the sealing of the second side cover or other side cover relative to the housing 2 in the same or analogous manner as described above.

Claims (15)

1. An axially split pump for conveying a fluid, having an axially split housing (2) that comprises a bottom part (21) and a cover (22), having a rotatable shaft (3) that determines an axial direction (A), and having at least one side cover (9) for closing the housing (2) in the axial direction (A), wherein the side cover (9) has a first contact surface (91) for cooperating with a second contact surface (23) provided at the housing (2), the second contact surface extending both over the bottom part (21) and the cover (22), wherein the bottom part (21) has a first sealing surface (212) and the cover (22) has a second sealing surface (222), wherein the bottom part (21) and the cover (22) can be fastened to one another in such a way that the two sealing surfaces (212, 222) have direct contact with one another, wherein at least one sealing groove (213) is provided in one of the sealing surfaces (212, 222) for the reception of a string-like sealing element (10), the sealing groove (213) extending up to the second contact surface (23) of the housing (2), characterized in that a recess (24) surrounding the shaft (3) is provided in the second contact surface (23) and in that a projection (92) surrounding the shaft (3) is provided in the first contact surface (91) of the side cover (9), wherein the recess (24) and the projection (92) are configured and arranged in such a way that they together form a ring-shaped groove (29) for the reception of a ring-shaped sealing element (11) in the mounted state of the side cover (9).
2. A pump in accordance with claim 1, in which a string-like sealing element (10) is inserted into the sealing groove (213) and a ring-like sealing element (11) is inserted into the ring-like sealing groove (29).
3. A pump in accordance with one of the preceding claims, in which the string-like sealing element (10) has a planar cross-sectional surface at the second contact surface (23).
4. A pump in accordance with any one of the preceding claims, wherein the sealing groove (213) substantially opens perpendicular into the ring-like groove (29).
5. A pump in accordance with claim 1, in which the sealing groove (213) is provided in the bottom part (21) of the housing (2).
6. A pump in accordance with any one of the preceding claims, in which the sealing groove (213) extends from the second contact surface (23) up to the end of the pump disposed opposite with respect to the axial direction (A), the end being configured for the reception of a second side cover (9) which is suitable for closing the housing (2) and in which the string-like sealing element (10) is inserted into the sealing groove (213), the sealing element extending over the total longitudinal extent of the sealing groove (213).
7. A pump in accordance with any one of the preceding claims, wherein the ring-like groove (29) formed by the recess (24) and the projection (92) has a substantially rectangular cross-sectional surface perpendicular to its longitudinal extent.
8. A pump in accordance with any one of the preceding claims, in which the ring-like groove (29) has a width (B) in the radial direction that is larger than the width of the string-like sealing element (10).
9. A pump in accordance with any one of the preceding claims, wherein a ring-like sealing element (11) is inserted into the ring-like groove (29), the ring-like sealing element preferably having a circular or elliptical cross-sectional surface.
10. A pump in accordance with any one of the preceding claims, in which the ring-like sealing element (11) has a height in the axial direction that is larger than the depth (T) of the ring-like groove (29) in the axial direction (A).
11. A pump in accordance with any one of the preceding claims, wherein the sealing groove (213) has a cut-out (214) at its opening into the second contact surface (23), the cut-out being arranged lying radially inward with respect to the sealing groove (213).
12. A pump in accordance with claim 11, wherein an elastic pre-loading element (217) is inserted into the cut-out, the pre-loading element exerting a radially outwardly directed pre-load on the string-like sealing element (11).
13. A pump in accordance with claim 12, in which the pre-loading element (217) is spring elastic and extends in parallel with the string-like sealing element (11) and is preferably configured as a spring (217).
14. A pump in accordance with any one of the preceding claims, in which the ring-like sealing element (11) and the string-like sealing element (10) are produced from an elastomer, in particular from a nitrile rubber, specifically from a nitrile butadiene rubber NBR.
15. A pump in accordance with any one of the preceding claims, configured as a centrifugal pump having a design pressure of at least 50 bar, preferably of at least 100 bar.

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