EP1850015A2 - Centrifugal pump - Google Patents

Abstract

The centrifugal pump has a pump housing (102) with a cylindrical pump area (109), and a nose (112) provided with a curve arranged in an inner side of the area limiting housing parts (103, 104), where the nose is made of processed plastic material. The nose is fixedly connected with the housing, and no additional sealing material is present between the nose and the housing. The part (103) is mounted in different positions with respect to the part (104) such that the orientation of a pressure side connection is variably selectable for different applications. An independent claim is also included for a procedure for production of a centrifugal pump.

Description

The invention relates to a centrifugal pump (100) having an at least two-part pump housing (102) made of injection-molded plastic material, the first housing part (103) having an axially formed suction nozzle (105) and a pressure nozzle formed approximately tangentially on a circumferential wall (114) (106) is integral and has a sealing region (133), via which it is sealed to a second, an electric motor (10) accommodating housing part (104) is connected, wherein the pump housing (102) includes a substantially cylindrical conveyor through-flow pump chamber (109) , whose inner contour (120) is spiral-shaped, in which a pump impeller (59) driven by the electric motor (10) is rotatably arranged and arranged with a rounding (111) within the pump space (109) bounded by the two housing parts (103, 104) ) provided spur (112), the best of injection molding processable plastic material ht and not with the first housing part (103) is integral, wherein the spur (112) is arranged in the pump chamber (109), that in the transition region (113) between the discharge nozzle (106) and the pump chamber (109) on the first housing part (103) forms a continuous and stepless transition from the peripheral wall (114) delimiting the pump chamber (109) via the spur (112) to the discharge nozzle (106).

In a known centrifugal pump of the generic type, the transition between the pump chamber and the discharge nozzle is formed edged. This edge causes eddies in the flow, which significantly reduce the efficiency of the pump. A continuous, non-edged transition between the pump chamber and the discharge nozzle, hereafter called the spur, reduces the flow resistance and increases the efficiency. In order to use molds with an economic life, however, an angular transition was unavoidable in the known centrifugal pump. This is due to the fact that the angle of Entformungsrichtungen between the first, the pump interior coaxially adjoining the suction nozzle and the discharge nozzle is at right angles in at least one of the spatial axes. To be able to realize a rounding at this point, one of these tool cores must inevitably have a tapered tongue. This form has an insufficient heat dissipation result, whereby the tool quickly wears at this point and thus has a short life. An economical production is therefore not possible.

A generic centrifugal pump is from the DE-PS 100 03 644 C1 known. In the known centrifugal pump, the service life problem has been solved in that the spur, which allows a laminar, efficiency-optimized flow, is integrally formed with the second housing part. In the assembled state then results in the desired optimum shape. The spray tools required for this purpose no longer have any thermally critical geometries. However, the arrangement of the spur on the second housing part may have a disadvantageous effect if the centrifugal pump for different applications with different arrangements of the pressure nozzle should be usable because the second housing part contains both pump attachment means and the spur, which indirectly determines the orientation of the pressure nozzle. In this case, the second housing part must be adapted to the particular application. This has a negative effect on the economy and productivity.

Therefore, it is an object of the present invention to maintain the advantages of the known centrifugal pump and still be able to use the same pump for different locations or applications with different installation conditions, with a simple assembly with minimum number of parts is sought.

This object is achieved in that the spur (112) with the second housing part (104) is not integral, that it is firmly connected to the pump housing (102) that there is no additional sealing material between the spur and the pump housing and that first housing part (103) with respect to the second housing part (104) is mountable in more than one position, so that the orientation of the pressure port (106) is different selectable for different applications. The first housing part (103) with the suction and the discharge nozzle can be secured by the separation of the spur from the second housing part (104) in any desired angular position to the second housing part. Since the spur is also separated from the first housing part, it can be manufactured with optimized tool geometry with high productivity. Due to the fixed connection of the spur with the pump housing, a high efficiency is achievable and noise problems that could arise from play between spur and pump housing are excluded. Parts and assembly costs can be saved if between the Spur and the pump housing no additional sealing material must be introduced.

Further advantageous embodiments of the invention are illustrated in the subclaims. One of the simplest ways to attach the spur in the pump housing is to mount this form-fitting, so that the geometric shape itself represents the connecting means. One of these positive connections is made by the dovetail shape by combining them with a complementary contour.

Especially in a pre-assembly situation, it may be advantageous if the spur is pressed into a corresponding receptacle of the housing. As a result, the spur can not fall out of the mounted position by incorrect handling again. It is basically a combination of positive and non-positive connection.

An alternative connection form becomes possible when the spider (112) of laser light transparent material and the first housing part (103) is made of a material absorbing the same laser light and the spur (112) is welded to the first housing part (103). This method is particularly suitable here because it must be avoided to arrange a weld within the pump chamber, because irregularities in the connection process could have a negative impact on the pump efficiency. In the case of laser transmission welding, on the other hand, the weld seam is located in an area which is unattainable for the pump medium.

In order to avoid thermal stresses or deformations during large temperature changes, which are not uncommon in cooling water pumps, it is necessary to ensure that the materials used for the spur and pump housing are at least approximately the same. Preferably, the spur should therefore consist of the same material as the pump housing itself.

The mentioned in the characterizing part of the main claim avoidance of sealing means between the spur and the pump housing is facilitated by the fact that the spur (112) extends completely within the pump housing (102) so that it does not form a housing part, thus, each seal is superfluous.

Also for the pump housing itself and its installation should be possible to dispense with a seal in the optimal case. If the pump housing parts to be joined are made of the same material, they can be welded together in a relatively simple manner. A particularly preferred welding technology is the already mentioned laser transmission welding, which requires a transparent material for the laser light and a material absorbing the same laser light. In this case, the laser light is passed through the transparent material of the one housing part and directed onto the absorbent material of the second housing part. The absorption of the laser light produces heat at the interface between the parts to be joined. Due to the high thermal resistance, this can not escape quickly enough, so that quickly reaches a temperature sufficient for the melting of the plastic in the boundary region. This creates an intimate connection. The materials of the two housing parts may be basically the same, with added for the absorbing effect additives that blacken the material. Russ is particularly suitable for this purpose.

Laser transmission welding has the disadvantage that the connection is bicoloured. This affects the visual appearance in open-view applications.

In a further development of the invention taking into account this aspect, the first housing part (103) has a first sealing area (133), the second housing part (104) has a second sealing area (144) and a third sealing area (145) and the motor housing (44) has a fourth sealing area (444). Furthermore, the second housing part (104) is integral with a containment shell (116) and the second seal area (144) and the third seal area (145) are so close together that a maximum of 20% of the total visible area of the centrifugal pump (100) and electric motor (10 ) are taken from the second housing part (104). This means that the size of the area that occupies the transparent material and possibly represents an optical restriction is minimized.

It is expedient to provide only the second pump fastening means for fastening the centrifugal pump (100). This allows the angular position of the first housing part (103) with respect to the second housing part (104) continuously selectable. Not infinitely but sufficient for most applications, the angular position can be selected when on the first and on the second housing part (103, 104) pump fastening means are provided, which are designed so that a large number of angular positions between the first and the second housing part are possible.

For optimum efficiency is provided, the curvature of the inner contour of the spur continuously pass from the curvature of the inner contour of the peripheral wall to the curvature of the inner contour of the pressure nozzle and form the inner contour of the spur as part of the spiral inner contour of the peripheral wall.

The peripheral wall of the pump chamber is cylindrical in order to be easily manufactured by injection molding without undercut can. Their resulting rectangular cross-section in the area of the pressure nozzle goes steadily and harmoniously into the circular shape of the said pressure nozzle.

In a further embodiment of the invention, it is provided to form the spur in the region of the pressure nozzle substantially semicylindrical and tapering point on the opposite side. As a result, turbulence is largely avoided and thus increases the efficiency.

The tapered contour does not meet the strength requirements in many cases. Therefore, it is provided to form the spur in the region of the pressure nozzle in a semi-cylindrical shape and on the opposite side to a, sufficient stability ensuring material thickness tapered.

So that no turbulence arises with this embodiment, it is provided to allow the spur at least partially immersed in the peripheral wall. It should be paid attention to rounded transitions in the peripheral wall, so that no notch effect arises, which could result in bursting of the pump chamber at high pressure.

The contour of the spur is on its inside part of a spiral channel. Thus, it goes from the cylindrical wall of the spiral channel steadily over into the approximately semi-cylindrical rounded curve. Its outer contour rests against the wall of the pump head, and the entire spur is designed so that it fits as harmoniously as possible into the wall of the pump head without impairing its strength.

In order to manufacture the pump housing economically, it is necessary that the spur parallel to the axis of rotation of the pump impeller has no undercut. This ensures easy removability of the pump housing from the injection mold.

• Fig. 1 eine räumliche Darstellung des ersten Pumpengehäuseteils einer bekannten Kreiselpumpe mit kantigem Sporn,
• Fig. 2 eine räumliche Darstellung des ersten Pumpengehäuseteils einer ungünstig herzustellenden Kreiselpumpe mit einstückig ausgeführtem runden Sporn,
• Fig. 3 eine räumliche Darstellung des zweiten Pumpengehäuseteils in einer bekannten Ausbildung,
• Fig. 4 eine räumliche Darstellung des bekannten Pumpengehäuses mit aufgeschnittenem erstem Gehäuseteil,
• Fig. 5 eine Explosionsdarstellung eines erfindungsgemässen Pumpengehäuses mit Sporn,
• Fig. 6 eine Darstellung des Sporns im eingebauten Zustand,
• Fig. 7 eine Explosionsdarstellung eines Gehäuses der erfindungsgemässen Kreiselpumpe und
• Fig. 8 eine Schnittansicht einer erfindungsgemässen Pumpe.

An embodiment will be explained in more detail with reference to the drawing.
Show it:

• 1 is a perspective view of the first pump housing part of a known centrifugal pump with angular spur,
• 2 is a perspective view of the first pump housing part of an unfavorable to produce centrifugal pump with integrally executed round spur,
• 3 is a perspective view of the second pump housing part in a known training,
• 4 is a perspective view of the known pump housing with cut first housing part,
• 5 is an exploded view of an inventive pump housing with spur,
• 6 is a representation of the spur in the installed state,
• 7 is an exploded view of a housing of the inventive centrifugal pump and
• Fig. 8 is a sectional view of a pump according to the invention.

Fig. 1 shows the first housing part 103 of a known centrifugal pump, consisting of an axially molded suction nozzle 105, an approximately tangentially formed discharge nozzle 106 and a substantially cylindrical, radially bounded by the wall 114 spiral pump chamber 109. The transition region 113 between the wall 114 and the discharge nozzle 106 is formed by a sharp edge 115. This edge 115 has an unfavorable effect on the efficiency of the pump, as at this point the laminar flow is disturbed sensitive and so the Flow resistance significantly increased.

2 shows a spatial representation of a fluid-mechanically favorable solution for the first housing part 103, consisting of an axially formed suction nozzle 105, a discharge nozzle 106 and a substantially cylindrical, radially bounded by a peripheral wall 114 helical pump chamber 109. A transition region 113 between the peripheral wall 114 and the discharge nozzle 106 forms a spur 112 with a circular contour 111. As part of a spiral channel of the spur 112 is shaped so that its curvature passes continuously from the peripheral wall 114 to an inner contour 120 of the pressure nozzle 106. Due to the hereby necessary tapered tongue of a tool positive caused lower downtime of a tool production of this housing part 103 is uneconomical. The spur 112 is disposed in the transition region between the narrowest and the widest point of the spiral gap between a pump impeller 59 and the inner contour 120 of the peripheral wall 114.

FIG. 3 shows a second housing part 104, which can be produced by injection molding technology, from one of the DE 100 03 644 C1 known centrifugal pump 100, which is effectively the centrifugal pump 100 of FIG. 2. The second housing part 104 is integral with a spur 112, which has a rounding 111. Furthermore, the second housing part has a sealing flange 133 and a rotor chamber 118, wherein the rotor chamber 118 is bounded by a gap pot 116, which is arranged in the air gap between a rotor and a stator (not shown) of an electric motor 10. The solution shown is applicable to both internal rotor and external rotor motors.

4 illustrates a first housing part 103 of the known centrifugal pump 100 in the cutaway state for the sake of clarity. The spur 112, which is integral with the second housing part 104, is shown arranged in a transition region 113 between a peripheral wall 114 and a discharge nozzle 106; it conforms to the inside of the circumferential wall 114. The first housing part 103 and the second housing part 104 have pump fastening means 122, which are designed in the form of fastening eyes which serve as screw passages. Since the spur 112 is integral with the second housing part 104, the first housing part 103 can occupy only a single angular position with respect to the second housing part 104, although four pump fastening means are uniformly distributed on the circumference of the pump housing.

FIG. 5 shows an exploded view of a pump housing 102, 103 with spur 112 according to the invention. The spur 112 has a dovetail contour 150 which extends with a complementary contour 151 of the pump housing 102, 103, which extends axially parallel to a cylinder-jacket-shaped region of the first housing part 103. is positively engaged (Fig. 6). The dovetail contour 150 has a V-shaped recess 152 which on the one hand allows a certain elasticity of the dovetail contour 150 and on the other hand bypasses the accumulation of material which is always to be avoided during the injection molding process. In the axial direction, the spur 112 is held in a form-fitting manner by a first pump housing part 103 and by a second pump housing part 104. The illustrated first housing part 103 further has a first flange 130 and a first ring 131. The first ring 131 has on its outer side a first sealing region 133, which is formed hermetically sealed with a second sealing region of the second housing part, not shown here. Furthermore, an intake-side axle receptacle 47 is shown, which is connected via three supports to the first housing part 103.

6 shows the spur in the installed state in the first housing part 103.

7 shows an exploded view of the housing of the centrifugal pump 100 with the first housing part 103, the second housing part 104 and the motor housing part 44. The first housing part 103 has an inlet nozzle 105, a discharge nozzle 106, a first flange 130 and a first ring 131 which connects to the first flange and has a first sealing region 133. The second housing part 104 comprises the containment shell 116, a second flange 140 and a second ring 141 which has on its inside a second sealing area 144 and a third sealing area 145. A motor housing part 44 comprises a third ring 441 and a fourth sealing area 444. The pump housing and the motor housing parts are hermetically welded together by means of the laser transmission welding process.

8 shows a sectional view through a centrifugal pump 100 according to the invention, comprising a pump housing 102, comprising a first housing part 103 and a second housing part 104 adjoining thereto. A motor housing part 44 delimits a drying space which is defined by a stator (40) of an electronically commutated direct current motor his control electronics is filled. The motor housing part 44 connects to the second housing part 102 and. The first and the second housing part 103, 104 define a wet space 101 of the centrifugal pump. The second housing part 104 is formed integrally with a split pot 116, which the wet space 101 of a drying room 99th

The wet room 101 includes an axle 49 which is fixedly installed between a cradle-side axle receptacle 48 and an intake-side axle receptacle 47. A knurling at the axis end prevents rotation of the axis 49 during pump operation. On the axis 49, a fixed bearing 54 is rotatably mounted, which is pressed in a hollow shaft 51 of the rotor 50. The shaft 51 is integral with a pump impeller 59 which includes a plurality of approximately spirally shaped wings 591 for the fluid delivery. The end faces of the fixed bearing 54 can be supported axially with the interposition of thrust washers against the gap-side axle receptacle 48 and against the intake-side axle receptacle 47. A hollow cylindrical ferrite magnet 52 is adhered to the hollow shaft 51, using an elastic adhesive which is inserted into four or five axially parallel grooves 511 formed in the hollow shaft.

The drying chamber 99 contains the stator 40 of the electronically commutated DC motor 10, which is designed in the form of a hollow cylindrical stator winding 41, wherein the magnetic field is guided in operation via claw poles in an alternating manner to the periphery of the can 116 and with the hollow cylindrical permanent magnet 52 in the wet space 101st interacts. The magnetic circuit is closed by a return ring 43, which is connected to the claw poles 42. The claw poles 42 are provided by encapsulation with an insulating body 46 which connects the claw poles 42 mechanically but not magnetically. The stator 40 has four pole pairs in the present example. The Isolierstoffkörper 46 is geometrically shaped so that the winding wires of the stator winding 41 with Klemmschneidkontakte having contact pins 62 are connected, said Klemmschneidkontakte are mechanically fastened in Isolierstoffkörper 46. The contact pins 62 are formed as combination contacts and pressed at its end opposite the clamping cutting contact 63 in a printed circuit board 61 and thereby contacted with this. The contact pins 62 contain one or two deformable press-fit zones for this purpose. The circuit board 61 includes a Hall sensor 71, an integrated circuit 70 (IC) for wiring the stator winding, a winding protection PTC, power devices, and power supply pins 64. The motor housing part 44 includes a connector housing 65 in which the connector pins 64 are arranged. Electronic components with a great deal of heat loss are heated via heat conducting films 67 to the wet space 101.

Conductor tracks, which serve for contacting components to be cooled, are dimensioned such that, for easier heat dissipation, conductor tracks 66 which are as wide as possible are provided on the printed circuit board 61. In order to achieve a particularly good utilization of the printed circuit board 61 and optimum heat dissipation, the different conductor tracks 66 are of different widths, depending on how much heat is generated in the component connection to be contacted. In the shaft 51, a longitudinal groove is formed as a cooling channel between a bottom 117 of the gap pot 116 and the pump impeller 59, which forces a continuous circulation of the fluid also in the interior of the containment shell 116. The printed circuit board is arranged between an end face 45 of the motor housing 44 and the bottom 117 of the can 116 and held in heat-conducting contact with the bottom 117 via the heat-conducting film 67.

The first housing part 103 has a first flange 130 and a first ring 131 adjoining thereto. The second housing part 104 has a second flange 140 and a second ring 141 adjoining thereto. The motor housing part has a third ring 441. The second flange 140 and the second ring 141 together form a T-shape in cross-section. There are four sealing areas 133, 144, 145 and 444 provided. The first sealing region is located on the radially outer side of the first ring 131 on the first housing part 103. Opposite on the radially inner side of the second ring 141 and the second housing part 104 is the second sealing region 144. Also on the radially inner side The third sealing region 145 is located on the radially outer side of the third ring 441 and of the motor housing part 44. The second housing part 104 consists of one for laser light of one wavelength or a wavelength range permeable material. The first housing part 103 and the motor housing part 44 are made of a material absorbing the same laser light. This allows a laser beam without heating the transparent material to a seam lead. There, the beam encounters material that absorbs the light and converts it to heat, causing the plastic to melt and intimately bond with the adjacent material.

Since the two seal areas to be welded are close to each other, it is easily possible to produce the two seams in one device and in one operation. The welding device may comprise two individual lasers, wherein one weld seam is produced in each case with one laser beam or it may comprise a single laser whose output beam is separated by a beam splitter into two Beams is divided, each of which generates one of the welds. In the present example, the laser beams are directed radially onto the pump housing.

LIST OF REFERENCE NUMBERS

10

electric motor

20

air gap

40

stator

41

stator

42

claw

420

annular disk-shaped stator laminations

421

The End

422

recess

423

web

424

air gap

43

Return ring

430

sheet metal bridge

431

slot

432

connecting slot

433

open slot

434

cutout

435

first edge

436

second edge

437

join

438

connecting means

439

sheet metal tongue

44

motor housing

45

Front side (of the motor housing)

46

insulating

461

receiving slot

462

mounting recess

463

fastener

464

attack

465

snap means

466

head Start

467

Bracket (for connector pin)

47

intake-side axle receptacle

48

gap pot-side axle mount

49

axis

50

rotor

51

wave

511

groove

512

disc

52

hollow cylindrical permanent magnet

521

working magnetization

522

Sensor trace magnetization

523

Front side (of the permanent magnet)

524

security gap

53

elastic connecting means

531-

first area (wide)

532

second area (narrow)

54

fixed bearing

58

Longitudinal groove (for secondary fluid circuit)

59

pump impeller

591

wing

60

electronics

61

circuit board

611

recesses

62

contact pin

63

Insulation displacement contact

64

Connector pin

641

projections

65

plug housing

66

conductor path

67

Heat conducting

70

Integrated circuit (IC)

71

Hall sensor

99

drying room

100

rotary pump

101

wet room

102

pump housing

103

first housing part

104

second housing part

105

suction

106

pressure port

109

pump room

111

round contour

112

spur

113

Transition area

114

peripheral

115

sharp edge

116

containment shell

117

ground

118

rotor chamber

119

deepening

120

spiral-shaped inner contour

121

admission

122

Pumps fasteners

123

rounding

130

first flange

131

first ring

133

first sealing area

140

second flange

141

second ring

144

second sealing area

145

third sealing area

150

dovetail contour

151

complementary contour

152

V-shaped recess

441

third ring

444

fourth sealing area

Claims (27)

Centrifugal pump (100) with an at least two-part pump housing (102) made of injection-molded plastic material, the first housing part (103) with an axially molded suction nozzle (105) and a pressure nozzle (106) integrally formed approximately tangentially to a peripheral wall (114) and a sealing region (133), via which it is connected tightly with a second housing part (104) accommodating an electric motor (10), wherein the pump housing (102) encloses a substantially cylindrical pumping space (109) through which the pumping medium flows. 120) is spiral-shaped, in which a pump impeller (59) driven by the electric motor (10) is rotatably arranged and a spur arranged within the pump space (109) bounded by the two housing parts (103, 104) and provided with a rounding (111) ( 112), which is made of injection-processable plastic material and not with the first Housing part (103) is integral, wherein the spur (112) is arranged in the pump chamber (109), that in the transition region (113) between the discharge nozzle (106) and the pump chamber (109) on the first housing part (103) a continuous and stepless transition from the pump space (109) bounding peripheral wall (114) via the spur (112) to the discharge nozzle (106), characterized in that the spur (112) with the second housing part (104) is not integral, that he with the pump housing (102) is firmly connected, that between the spur and the pump housing is no additional sealing material and that the first housing part (103) with respect to the second housing part (104) is mountable in more than one position, so that the orientation of the Pressure nozzle (106) for different applications is different selectable. Centrifugal pump according to claim 1, characterized in that the spur (112) is positively connected to the pump housing (102). Centrifugal pump according to claim 1 or 2, characterized in that the spur (112) has a dovetail contour (150) which is in positive engagement with a complementary contour (151) of the pump housing (102). Centrifugal pump according to claim 1, 2 or 3, characterized in that the spur (112) in the pump housing (102) is pressed. A centrifugal pump according to claim 1, 2, 3 or 4, characterized in that the spur (112) of a material transparent to laser light and the first housing part (103) consists of a material absorbing the same laser light and the spur (112) with the first housing part (103) is welded. Centrifugal pump according to at least one of the preceding claims, characterized in that the spur (112) consists of a material which has at least approximately the same thermal expansion coefficient as the first housing part (103). Centrifugal pump according to at least one of the preceding claims, characterized in that the spur (112) consists of the same material as the first housing part (103). Centrifugal pump according to at least one of the preceding claims, characterized in that the spur (112) extends completely within the pump housing (102), so that it does not form a housing part. Centrifugal pump according to at least one of the preceding claims, characterized in that the pump housing (102) consists exclusively of the housing material of the first and the second housing part (103, 104) and is liquid-tight without additional sealing materials. Centrifugal pump according to at least one of the preceding claims, characterized in that the first housing part (103) with the second housing part (104) is welded. Centrifugal pump according to at least one of the preceding claims, characterized in that the second housing part (104) consists of a transparent material for laser light and the first housing part (103) consists of a same laser light absorbing material. Centrifugal pump according to at least one of the preceding claims, characterized in that the second housing part (104) with a subsequent motor housing (44) is welded. Centrifugal pump according to at least one of the preceding claims, characterized in that the second housing part (104) consists of a material transparent to laser light and the motor housing (44) consists of a material absorbing the same laser light. Centrifugal pump according to at least one of the preceding claims, characterized in that the first housing part (103) has a first sealing area (133), the second housing part (104) has a second sealing area (144) and third sealing area (145) and the motor housing (44) fourth sealing region (444). Centrifugal pump according to at least one of the preceding claims, characterized in that the second housing part (104) is integral with a containment shell (116). Centrifugal pump according to at least one of the preceding claims, characterized in that the second sealing region (144) and the third sealing region (145) are so close to each other that a maximum of 20% of the total visible surface area of centrifugal pump (100) and electric motor (10) from the second housing part (104). Centrifugal pump according to at least one of the preceding claims, characterized in that only on the second housing part (104) pump fastening means (122) for attachment of the centrifugal pump (100) are provided. Centrifugal pump according to at least one of the preceding claims, characterized in that fastening means are provided on the first and the second housing part (103, 104), wherein these are formed so that a large number of angular positions between the first and the second housing part are possible. Method for producing a centrifugal pump according to at least one of the preceding claims, characterized in that the first housing part (103) with the second housing part (104) and the second housing part (104) with the motor housing (44) are connected to each other in one operation by laser transmission welding , Centrifugal pump according to at least one of the preceding claims, characterized in that the curvature of the inner contour (119) of the spur (112) continuously from the curvature of the inner contour of the peripheral wall (114) to the curvature of the inner contour of the pressure port (106) merges and the inner contour (119) of the spur (112) is part of the spiral-shaped inner contour (120) of the circumferential wall (114). Centrifugal pump according to at least one of the preceding claims, characterized in that the cross section of the tangentially to the first housing part (103) integrally formed pressure port (106) in the region of the spur (112) is substantially rectangular. Centrifugal pump according to at least one of the preceding claims, characterized in that the cross section of the tangentially to the first housing part (103) integrally formed pressure nozzle (106) merges continuously from a substantially rectangular into a round shape. Centrifugal pump according to at least one of the preceding claims, characterized in that the spur (112) in the region of the pressure nozzle (106) is substantially semi-cylindrical and formed on the opposite side tapering point. Centrifugal pump according to at least one of the preceding claims, characterized in that the spur (112) in the region of the pressure nozzle (106) is approximately semi-cylindrical and tapered on the opposite side to a, sufficient stability ensuring material thickness. Centrifugal pump according to at least one of the preceding claims, characterized in that the spur (112) at least partially immersed in the peripheral wall (114) and the inner contour (119) of the spur to the peripheral wall (114) adjoins. Centrifugal pump according to at least one of the preceding claims, characterized in that the peripheral wall (114) at least in the region of the spur (112) kerbwirkungsfrei, z. B. rounded, shaped. Centrifugal pump according to at least one of the preceding claims, characterized in that the spur (112) parallel to the axis of rotation of the pump impeller (59) has no undercut.

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