EP1522738B1 - Volute for a centrifugal pump - Google Patents

Description

The invention relates to a spiral housing for a centrifugal pump and to a use of the spiral housing.

Spiral housing for centrifugal pumps are known. In "Turbomachinery" by Carl Pfleiderer, Hartwig Petermann, 6th edition, pp. 339 to 343 aspects in the design of volute casings are shown. It is pointed out that the lateral walls of the spiral housing should be designed as surfaces of revolution. In the known spiral housings is generally disadvantageous that they have a relatively large outer diameter, which in turn makes a relatively large space required. However, this is not available in many cases.

In the automotive technical journal of 01.02.1995 is disclosed on pages 36 to 90, a spiral housing for a centrifugal pump having a flow cross-section in the central region of the flow spiral whose ratio of the first part height, measured between the farthest from the inlet of the flow medium and parallel to the longitudinal axis of the inlet boundary of the flow cross-section and the intersection of the length and the width, to the second part height, measured between the intersection of the length and the width and the closest to the inlet of the flow medium and parallel to the longitudinal axis of the eintrittsaverlaufenden boundary of the flow cross-section is in the range of 0.25 to 1. The DE 16 28 361 A1 discloses a centrifugal blower, particularly one which is frequently used in cases where minimum weight, minimum size and blower output are required. The centrifugal fan has an impeller receiving housing, the housing having a spiral bound flow chamber of generally elliptical cross-section with an inner circumferential inlet and an outlet for the air delivered by the impeller. The ratio of the minor axis dimension to the major axis dimension of the elliptical cross-section progressively increases from one end of the small radius chamber toward the chamber outlet.

The DE 199 56 380 C1 discloses a fluid pump with a motor housing for the cooling circuit of a motor vehicle. This fluid pump has a claw-pole stator and a rotor separated from the claw-pole stator by a tube-separated rotor immersed in a liquid and having an impeller. In the liquid pump, the jaws of the claw cushion are an integral part of the tube, which forms part of a motor housing.

The invention is therefore based on the object to provide a spiral housing for a centrifugal pump, which has the smallest possible outer diameter at a maximum throughput of the flow medium. Furthermore, the volute should be designed so that the highest possible efficiency of the centrifugal pump can be realized.

The object underlying the invention is achieved by a spiral housing for a centrifugal pump, which in the central region of the flow spiral a flow cross-section whose ratio of the length to the width is in the range of 1.5 to 2 and whose ratio of the first. Partial height, measured between the furthest from the entrance of the Flow medium remote and running parallel to the longitudinal axis of the inlet boundary of the flow cross-section and the intersection of the length and the width, the second part height, measured between the intersection of the length and the width and the closest to the inlet of the flow medium and parallel to the longitudinal axis of the inlet extending boundary of the flow cross-section in the range of 0.25 to 1, wherein the limit de s flow cross-section and the impeller of the centrifugal pump closest further boundary of the flow cross section at right angles to each other α. The spiral housing may be formed in one piece or in several parts. The flow spiral is typically divided into three parts, an entry area, a central area, and an exit area. As a rule, roundings must be provided at the entry region so that the flow medium from the inlet flows into the flow spiral in a streamlined manner. Likewise, the exit region has curves which facilitate a transition to the exit from the volute casing. In between lies the middle range, where some design parameters should be kept constant. Even in the central region of the flow cross section is not continuously constant, but increases continuously in the direction of the outlet of the spiral housing. The length is to be understood as the largest length dimension of the flow cross section, which can be measured at any point of the flow cross section parallel to the longitudinal axis of the inlet of the flow medium. The width is to be understood as the greatest possible width dimension that can be measured at any point of the flow cross-section perpendicular to the longitudinal axis of the inlet of the flow medium. The length and the Width are thus perpendicular to each other and have the common point of intersection. The width is split at the point of intersection into a first partial height and a second partial height. The sum, formed from the first partial height and from the second partial height then again gives the width. By the right angle α is meant an angle of 90 ° technically. This means that due to manufacturing tolerances, even those angles are to be understood that are above 90 ° or below 90 °. Small angular deviations should thus still fall through the term "right angle α". It has surprisingly been found that can be realized by the structural design of the spiral housing relatively high flow rates of flow media, wherein the outer diameter of the spiral housing can be kept relatively small. At the same time, the centrifugal pump with this spiral housing to a relatively high efficiency, which is defined as a product of the throughput with the pressure increase relative to the supplied total power. Due to the relatively small outer dimensions of the spiral housing, the centrifugal pump can also be used advantageously when only a relatively small space is available.

A preferred embodiment of the invention consists in that the spiral housing consists of a first housing part and a second housing part, the first housing part forming the boundary and the second housing part 2 forming the further boundary of the flow cross section. It is advantageous that the preparation of the spiral housing can be done for example by a casting process without lost cores. The joining of the first housing part and the second Housing part can be done by way of example in a simple manner by a screw or by gluing.

According to a further embodiment of the invention, the first housing part at its outer boundary holes, which extend parallel to the longitudinal axis of the inlet of the flow medium. In this way, the first housing part can be fastened in an advantageous manner with screw on the drive housing of the centrifugal pump.

A further embodiment of the invention is that the second housing part is limited outside circular and on the outside has a circumferential groove. In the circumferential groove sealing elements, such as a sealing ring can be fixed in a relatively simple manner. Furthermore, it is possible to introduce into the groove adhesives to connect the second housing part in a relatively simple manner with the first housing part.

A further embodiment of the invention provides that the first housing part has on its outer side a contact point for an electrical connection. It may be formed, for example, as a plug connection for an electrical contact. It is advantageous that the electric power supply of the centrifugal pump can be done in a simple manner via the first housing part, wherein the space required for this also can be kept relatively small.

According to a further embodiment of the invention, the first housing part on its side opposite the inlet side on a circular opening, the inner diameter of the Outer diameter of the second housing part is formed opposite to complementary. Under the complementary design is to be understood that the second housing part can be fitted positively into the first housing part. It is advantageous that the second housing part can be integrated nearly f luchtend in the first housing part, which also leads to an additional saving of space.

A further embodiment of the invention provides that the second housing part has a central opening for the impeller of the centrifugal pump, which is designed as a bearing for the drive. For example, the central opening is circular in shape and stiffened at its inner edges, so that the inserted with one end into the central opening drive for the impeller of the centrifugal pump can be fixed in the central opening and thus stored. An additional arrangement of a bearing can be dispensed with in an advantageous manner.

According to a further embodiment of the invention, the second housing part is a part of the drive housing. The term "drive housing" is to be understood that housing in which the electric drive for the impeller of the centrifugal pump is arranged. It is advantageous that can be dispensed with a separate individual production of the second housing part.

The invention is finally still the use of the spiral housing as a housing for a cooling water centrifugal pump in a motor vehicle. It is advantageous that the in a motor vehicle only very limited available space can be used in an optimal way.

The invention will be described below with reference to the drawing (in which Fig. 1a b); Fig. 2a b); Fig. 3 to Fig. 7 ; Fig. 8a ), b), c); Fig. 9 ) explained in greater detail and by way of example.

Fig. 1a ), b) shows the inside of the first housing part and the inside of the second housing part in plan view.

Fig. 2a ), b) shows the inside of the first housing part and the second housing part in a three-dimensional representation.

Fig. 3 shows the first housing part and the second housing part three-dimensionally in the assembled state.

Fig. 4 shows the first housing part and the second housing part in the assembled state in a three-dimensional representation from another angle.

Fig. 5 shows the view into the outlet of the spiral housing in three-dimensional form.

Fig. 6 shows the top view of the Spiralge housing with the middle area.

Fig. 7 shows enlarged the section DD according to Fig. 6 ,

Fig. 8a ), b), c) shows the sections AA, BB and CC according to Fig. 6 ,

Fig. 9 shows, the first housing part in three-dimensional representation with the contact point.

In Fig. 1a ) is the first housing part 1 and in Fig. 1b ), the second housing part 2 in plan view, each seen from the inside, shown. The first housing part 1 has an inlet E of the flow medium and an outlet A of the flow medium. Further, the first housing part 1 is provided on its outside with holes 1 ', which serve the attachment to a drive housing (not shown). The second housing part 2 has a central opening L for the impeller of the centrifugal pump (not shown). This central opening L may optionally also be designed as a bearing for the drive. The flow spiral has a beginning 2 * and an end 2 **. In this all-encompassing region, the flow medium, which is usually an aqueous solution, flows in a star-shaped manner starting from the inlet E, that is, from the inside, centrally against the outer boundary of the flow spiral. In the assembled state, the second housing part 2 engages with its protruding tongue 2 'in the first housing part 1 such that the first edge a of the first housing part 1 bears against the second edge b of the second housing part 2. Furthermore, then also the first stop surface c on the second stop surface d (each shown dotted) and the third stop surface e on the fourth stop surface f (each shown with wavy lines). The surface g of the first housing part 1, however, does not touch the second housing part 2 of the spiral housing in the assembled state. In the assembled state of the spiral housing are the closest to the inlet E of the flow medium and parallel to Longitudinal axis of the inlet E extending boundary j of the flow cross-section and the impeller of the centrifugal pump the closest further boundary h of the flow cross-section at right angles α (not shown) to each other. In this case, the first housing part 1 forms the boundary j and the second housing part 2 forms the further boundary h of the flow cross section. The further limitation h of the flow cross-section connects directly to a gekrümm th part of the flow cross-section.

In Fig. 2a ) is the first housing part 1 and in Fig. 2b ), the second housing part 2, in each case three-dimensional and seen from the inside, shown. The second housing part 2 is delimited on the outside in a circular manner and has on the outside a peripheral groove 2 "into which, for example, a peripheral seal can be introduced Realized limit h of the flow cross-section, which is at a right angle α (not shown) to the boundary j of the flow cross section.The behind the end 2 ** in the direction of the outlet A of the Strömungsme medium extending boundary of the flow cross section thus does not extend planar, but is A similarly curved boundary (not shown) is also visible behind the beginning 2 * of the flow spiral in the direction of the outlet A of the flow medium in the so-called initial region the middle range (nic ht shown) for the continuous valid is that the boundary j to the boundary h at a right angle α (not shown) to each other.

In Fig. 3 is the spiral housing, which consists of a first housing part 1 and a second housing part 2, shown three-dimensionally in the assembled state. The first housing part 1 is formed complementary to the second housing part 2, so that the second housing part 2 can be fitted with its outer diameter in the first housing part 1 curse tend. In this way, an additional space requirement is avoided. For fastening the spiral housing to a drive housing in which the motor for driving the impeller of the centrifugal pump (not shown), 1 screws can be passed through the holes 1 'at the outer boundary of the housing part, which then bolted directly to the drive housing become. In this way, the second housing part 2 between the drive housing (not shown) and the first housing part 1 of the spiral housing is held positively, so that can be dispensed with additional fastening means for fixing the first housing part 1 on the second housing part 2. These measures also make it possible to restrict installation space.

In Fig. 4 is the spiral housing in the assembled state according to Fig. 3 presented in three dimensions from a different perspective. The spiral housing is very compact and requires only a very limited space due to its minimized outer diameter.

In Fig. 5 is the spiral housing, consisting of the first housing part 1 and the second housing part 2 three-dimensional view of the outlet A of the flow medium. The illustration illustrates the compact design of the spiral housing.
In Fig. 6 is the plan view of the spiral housing with a view of the first housing part 1 shown. The approximate center area M of the flow spiral is highlighted by the dashed arrow. Depending on the size of the spiral housing and depending on the shape of the connecting parts, which has a respective influence on the structural design of the inlet E of the flow medium and the outlet A of Strömungsm ediums, this middle region M can vary in size. Within the central region M, the boundary j (not shown) and the further boundary h (not shown) of the flow cross-section are at right angles α (not shown) to one another.

In Fig. 7 is the spiral housing in section D -D according to Fig. 6 shown. It is thus a section through the central area (not shown). The Strömun gsspirale has a flow cross-section whose ratio of the length X to the width Y is in the range of 1.5 to 2. The ratio of the first partial height Y1, measured between the boundary of the flow cross section furthest away from the inlet E of the flow medium and parallel to the longitudinal axis of the inlet E, and the intersection P of the length X and the width Y, to the second partial height Y2 between the Intersection point P of length X and width Y and the closest to the inlet E of the flow medium and parallel to the longitudinal axis of the entrance E extending boundary j of Flow cross-section is measured in the range of 0.25 to 1, wherein the boundary j of the flow cross-section and in the impeller of the centrifugal pump nearest further boundary h of the flow cross section at right angles to each other α. In this case, the first housing part 1 form the boundary j and the second housing part form the further boundary h of the flow cross section. The flow space S of the flow spiral is shown hatched. The width of the protruding tongue (not shown) of the second housing part 2 corresponds to the constant flow width K of the inlet opening into the flow space S of the flow spiral. In this case, the flow width K is constant over the entire region of the flow spiral in a particularly advantageous manner.

In Fig. 8a ) is the section AA according to Fig. 6 shown. In Fig. 8b ) is the section BB according to Fig. 6 shown. In Fig. 8c ) is the section CC according to Fig. 6 shown. At the in Fig. 8a ) section AA is a section through the flow spiral, which is attributable to the initial region of the flow spiral, thus not the central region (not shown). This initial region of the flow spiral lies directly behind the beginning (not shown) of the flow spiral and has a curved boundary bordering on the impeller of the centrifugal pump (not shown). A limitation j of the flow cross-section and a further boundary h of the flow cross-section, which are at right angles to each other α, are thus not realized. In contrast to Fig. 8a ) are the in Fig. 8b ) and c) shown sections B -B and CC again the middle area (not shown) to assign. On the entry of the length, the width and the first partial height and the second partial height with the representation of the intersection was in Fig. 8b ), c) omitted for reasons of clarity. As well as in Fig. 7 is in Fig. 8b ), c) the transition of the further boundary h in a curved part i of the flow cross-section de utlich. The respective flow spaces S of the flow spiral are in Fig. 8a ), b), c) again shaded.

In Fig. 9 the first housing part 1 of the spiral housing is shown three-dimensionally with a view to the inlet E of the flow medium. The first housing part 1 has on its outside a contact point 3 for an electrical connection. About this contact point 3, which is designed as a kind of connector for electrical contact, the drive (not dargestell t) of the centrifugal pump (not shown) is supplied with electrical energy. However, it is also possible to supply via the contact point 3 corresponding control or control signals of the centrifugal pump. Due to the relatively small outer diameter d of the first housing part 1 of the spiral housing, it is particularly advantageously possible to arrange the contact point 3 as close as possible to the inlet E of the flow medium, so that the requirement of installation space can be additionally reduced.

Claims (9)

1. Volute for a centrifugal pump, of which volute the ratio of a first subheight (Y1), measured between the flow cross section boundary furthest away from the inlet (E) of the flow medium and running parallel to a longitudinal axis of the inlet (E) and the intersection point (P) of the length (X) and width (Y), to a second subheight (Y2), measured between the intersection point (P) of the length (X) and width (Y) and the flow cross section boundary (j) lying nearest to the inlet (E) of the flow medium and running parallel to the longitudinal axis of the inlet (E), lies in the range of 0.25 to 1, the flow cross section boundary (j) and the further flow cross section boundary (h) lying nearest to the impeller of the centrifugal pump standing at right angles α to one another, characterized in that the volute has in the middle region (M) of the flow spiral a flow cross section of which the ratio of the length (X) to the width (Y) lies in the range of 1.5 to 2.
2. Volute according to Claim 1, which consists of a first housing part (1) and of a second housing part (2), the first housing part (1) forming the boundary (j) and the second housing part (2) forming the further boundary (h) of the flow cross section.
3. Volute according to Claim 2, in which the first housing part (1) has at its outer boundary bores (1') which run parallel to the longitudinal axis of the inlet (E) of the flow medium.
4. Volute according to Claim 2 or Claim 3, in which the second housing part (2) has externally a circular boundary and on the outside has a peripheral groove (2").
5. Volute according to one of Claims 2 to 4, in which the first housing part (1) has on its outside a contact point (3) for an electrical connection.
6. Volute according to one of Claims 2 to 5, in which the first housing part (1) has, on its side lying opposite the inlet (E), a circular orifice, the inside diameter of which is designed to be complementary to the outside diameter of the bipartite housing part (2).
7. Volute according to one of Claims 2 to 6, in which the second housing part (2) has for the impeller of the centrifugal pump a central orifice (L) which is configured as a bearing for the drive.
8. Volute according to one of Claims 2 to 7, in which the second housing part (2) is part of the drive housing.
9. Use of the volute according to one of Claims 1 to 8 as a housing for a cooling-water centrifugal pump in a motor vehicle.

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