EP2208890A2 - Rotation displacement pump - Google Patents

Abstract

The pump (2) has an accommodating chamber (4) in a pump housing (3), and rotary displacement elements (5, 6) e.g. hypotrochoid housing (10) and star-shaped internal rotary displacement element (15), accommodated in the chamber. A bypass enables a reverse flow of a pumped medium from an outlet region (27) into an inlet region (26) of the chamber. The elements and/or a swivel plate, connected with the elements, have an opposing surface limiting the bypass, where an opposing surface normal of the surface has a component aligned opposite to a periphery normal of a periphery (21) of the elements.

Description

The invention relates to a rotary displacement pump for pumping a medium, having a pump housing, a receiving chamber formed in the pump housing with an inlet region and an outlet region and at least one Rotationsverdrängerelement recorded in the receiving chamber, which is rotatably supported by at least one bearing in the pump housing and has at least one boundary surface, with which it limits at least one working space of the pump.

In the case of rotary displacement pumps, the medium is conveyed from an inlet region into an outlet region by means of a rotational movement of a displacement element or a plurality of displacement elements through a closed working space. Apart from design-related leaks, the medium - even at a standstill of the pump - this does not flow in the opposite direction, ie from the outlet to the inlet area. Due to the compression of the medium in the working space of the pump, a considerable pressure is produced on a boundary surface of the rotary displacement element, in particular in the outlet area. Since this Rotationsverdrängerelements is rotatably mounted in the pump housing by means of a bearing or more bearings, this bearing must absorb high forces.

The invention is therefore based on the object to reduce a superposition by acting forces resulting total force on the Rotationsverdrängerelement or on the bearing.

To achieve this object, it is provided that the rotary positive displacement pump has at least one bypass, which allows a return flow of a portion of the pumped medium from the outlet to the inlet region, wherein the Rotationsverdrängerelement and / or connected to the Rotationsverdrängerelement rotary member has at least one counter surface which the bypass limited and whose Gegenflächennormale has at least one component which is aligned opposite to the boundary surface normal of the boundary surface. The pressure in the working space of the pump results in a resultant force on the rotary displacement element along the boundary surface normal. This force is - at least partially - compensated by a counterforce that exerts through the pressurized medium in the bypass on the opposite surface. By superimposing the force resulting from the pressure in the working space on the boundary surface and the corresponding counterforce by the pressure in the bypass, the resulting total force acting on the Rotationsverdrängerelement or its bearing is reduced. The bearing can be designed accordingly smaller. The Rotationsverdrängerelement is mounted either directly on the bearing or on the bearing and at least one further intermediate element, in particular the rotary member in the housing. The bypass is in particular a bypass running within the pump housing. The medium is preferably a liquid medium.

In particular, it is provided that the boundary surface is an axial boundary surface, which limits the working space axially. The Rotationsverdrängerelement is usually supported by a bearing designed as a radial bearing rotatably mounted relative to the pump housing. Such a radial bearing is usually not suitable for receiving higher axial forces. However, such forces occur when the Rotationsverdrängerelement has an axial boundary surface. In order to reduce the resulting total axial force, the mating surface has a mating surface normal having a component aligned opposite the axial boundary surface normal of the axial mating surface. The compensation of the resulting axial forces results in a reduction of the total axial force the Rotationsverdrängerelement, connected to the Rotationsverdrängerelement rotating part and / or the bearing.

According to a development of the invention, it is provided that the mating surface is arranged opposite to the boundary surface. The pressure of the medium in the working space, which acts on the boundary surface is compensated - at least partially - by the back pressure, which exerts the medium in the bypass on the counter surface, in a way that no additional tilting moment on the Rotationsverdrängerelement, the rotating part and / or the bearing works.

According to an advantageous embodiment of the invention it is provided that the bypass has a valve for controlling and / or regulating the flow of the back-flowing medium through the bypass. The valve is used for backpressure limitation. By means of a sensor, the volume flow of the medium is determined on / in the valve. By means of the valve, a variable counter pressure corresponding to the volume flow is generated on the mating surface, which is regulated as required.

In particular, it is provided that Rotationsverdrängerelement is designed as a rotary piston. A rotary displacement pump with rotary piston is in particular a rotary piston pump. Rotary lobe pumps are rotary lobe pumps, rotary vane pumps, rotary lobe pumps and gear pumps.

In an advantageous embodiment of the invention it is provided that one of the Rotationsverdrängerelemente is formed as a housing member which surrounds a trained as Innenrotationsverdrängerelement Rotationsverdrängerelement eccentric. The rotatably mounted housing element and the Innenrotationsverdrängerelement together form a Verdrängerelementesatz. A rotary displacement pump with such a displacement element set is, for example, an internal gear pump, also a sickle pump called, or a gerotor pump, also called gerotor pump. In the internal gear pump and the toothed ring pump, the internal rotation displacement element designed as a toothed wheel (toothed wheel) engages with its teeth in interdental spaces (chambers) of an internal toothing of the rotatably mounted housing element. The housing element is designed as a toothed ring or has a toothed ring. In the internal gear pump, the medium to be conveyed is carried in the spaces between the tooth gaps of the gear and the ring gear, the teeth being sealed by a crescent-shaped intermediate member. In the case of the gerotor pump, on the other hand, the medium is conveyed by the volume-changing working space between the tooth gaps and the teeth of the two rotary displacement elements.

In an advantageous embodiment of the invention, it is provided that the housing element is designed as a hypotrochoid housing with n chambers and the further internal rotation displacement element n-1 has corresponding teeth for engagement in the chambers. The chambers and teeth are designed so coordinated that they determine the shape and volume of the working space or the volumes of the work spaces without additional element. The internal rotation displacement element has exactly one tooth less than the housing element has chambers. The volume of the working space is changed by the movement of the two Rotationsverdrängerelemente (the displacement element set) such that the pump sucks the medium in the inlet area, compressed on the way to the outlet area and ejects there. For this purpose, the volume of the working space between the inlet area and the outlet area is first increased by the movement of the rotary displacement elements and then reduced again. The number n of the chambers is preferably seven (n = 7).

It is advantageously provided that the bearing is a roller bearing or a plain bearing. If the bearing is a radial bearing, then it is a radial bearing in the form of a rolling bearing or a plain bearing for radial bearing of Rotationsverdrängerelements. Alternatively or additionally, the bearing is a thrust bearing. In particular, the thrust bearing is a combined axial / radial bearing. If the bearing is a roller bearing, it is preferably a ball bearing, roller bearing or needle roller bearings. If the bearing is designed as a sliding bearing, then this has a ring-shaped closed bearing bush or a bearing bush composed of bearing shells.

It is provided that the rotary member is a shaft or has a shaft. In this case, the Rotationsverdrängerelement is preferably rotatably supported in the housing via this shaft. It is provided in particular that the shaft forms the bypass. The shaft is preferably a hollow shaft forming an axial channel.

In an advantageous embodiment of the invention it is provided that the Rotationsverdrängerelement is driven by an associated drive motor Rotationsverdrängerelement. The drive motor preferably drives the rotary displacement element via the rotary part, in particular the shaft. Such a shaft is a drive shaft of the pump. In this case, provision is made in particular for a coupling, in particular a magnetic coupling, to be arranged between the shaft and the drive motor. Due to the interposed clutch, the output of the drive motor and the shaft are not permanently connected to each other, but rotatably connected. It is provided in particular that the coupling forms the bypass.

The valve has according to an advantageous embodiment of the invention, a valve-internal mechanism for valve-internal control of the pressure difference .DELTA.p of the medium in response to a pressure prevailing on the input side of the valve.

It is advantageously provided that the pump is designed as a movement seal-free rotary displacement pump. A motion seal is a dynamic seal located between two mutually moving parts.

In an advantageous embodiment of the invention it is provided that the pump housing and / or the shaft made of stainless steel and / or a Hastelloy nickel-based alloy and / or titanium. These materials guarantee high mechanical strength and high corrosion resistance at temperatures from -20 ° C to + 200 ° C.

Finally, it is advantageously provided that the bearings and / or Rotationsverdrängerelemente- at least in part - from the materials Teflon and / or carbon and / or peek and / or non-seizing alloys (non-galling alloys) exist. These materials (teflon, carbon, peek, and non-seizing alloys) are materials that can not weld with the aforementioned materials (stainless steel, Hastelloy nickel base alloy, and titanium) during operation of the pump.

Fig. 1

eine schematische Darstellung des wesentlichen Aufbaus einer als Gerotorpumpe ausgebildeten Rotationsverdrängerpumpe,

Fig. 2

einen Längsschnitt durch eine Gerotorpumpe gemäß eines bevorzugten Aus- führungsbeispiels der Erfindung und

Fig. 3

im oberen Bereich eine Draufsicht auf die Gerotorpumpe und im unteren Be- reich eine Schnittdarstellung durch die Gerotorpumpe der Fig. 2.

The invention will be explained in more detail with reference to the figures, in which:

Fig. 1

a schematic representation of the essential structure of a rotary gerotor pump designed as a rotary displacement,

Fig. 2

a longitudinal section through a gerotor pump according to a preferred embodiment of the invention and

Fig. 3

in the upper area a plan view of the gerotor pump and in the lower area a sectional view through the gerotor pump of Fig. 2 ,

The Fig. 1 shows the essential structure and designed as a gerotor pump 1 Rotationsverdrängerpumpe 2 with a pump housing 3 and arranged in the pump housing 3 cylindrical receiving chamber 4. In the receiving chamber 4 are two rotatable mounted rotary displacement elements 5, 6, which together form a displacement element set 7.

The first Rotationsverdrängerelement 5 is formed as a housing member 8 which is rotatably mounted about a rotation axis 9. This housing element 8 designed as a hypotrochoid housing 10 has two parts, a ring part 11 and an axially adjoining wall part 12. The ring member 11 has on its inner circumference 13 seven circumferentially uniformly distributed chambers 14. In the rotatably mounted housing element 8 designed as a star-shaped Innenrotationsverdrängerelement 15 second Rotationsverdrängerelement 6 is arranged, which has six teeth 17 on its outer circumference 16. The Innenrotationsverdrängerelement 15 is rotatably mounted about an axis of rotation 18 which does not coincide with the axis of rotation 9 of the housing member 8. The axes of rotation 9 and 18 are spaced apart such that a part of the teeth 17 engages in a part of the chamber 14 and form working spaces 19 between the other teeth 17 and chambers 14. Each of the working spaces 19 is bounded by a part of the inner circumference 13 of the annular part 11 belonging to the housing element 8, a part of the outer circumference 16 of the inner rotary displacement element 15 and a limiting surface 21 of the housing part 8 belonging to the housing part 8. A respective part of the inner circumference 13 and the outer circumference 16 thus likewise forms a delimiting surface 21. A further second axial limiting surface (not shown) opposite the axial limiting surface 20 of the wall part 12 is formed by a pump cover 22.

On opposite sides of the pump cover 22 are an inlet channel 23 and an outlet channel 24 of the pump 2. The inlet channel 23 is connected via an inlet kidney 25 to an inlet region 26 of the receiving chamber 4. An outlet region 27 of the receiving chamber 4 lying opposite the inlet region 26 is connected to the outlet channel 24 via an outlet kidney 28 formed in the pump cover.

The result is the following mode of operation of the pump 2: Upon rotation of the housing element 8 (arrow 29) due to the engagement of the teeth 17 of the Innenrotationsverdrängerelements 15 in the chambers 14 of the housing member 8 to co-rotation of the Innenrotationsverdrängerelements 15 (arrow 30). As from the snapshot according to Fig. 1 can be seen, the teeth 17 engage only over a certain angular range - in Fig. 1 in the lower area - completely in the chambers 14, whereas, however, in a diametrically opposite angular range - Fig. 1 above - the teeth 17 of the internal rotation displacement element 15 do not engage in the chambers 14 of the housing element 8.

During the rotation (arrows 29, 30) of the displacer element set 7, the teeth 17 overtake the chambers 14 in the latter angular range in the direction of rotation (arrow 26). When unscrewing from the first-mentioned angular range of engagement arises in each case between two adjacent teeth 17 of the Innenrotationsverdrängerelements 15 and a chamber 14 of the housing member 8 one of the moving with Verdrängerelementes 7 moving and increasingly increasing work spaces 19, which then approaching the first-mentioned angle range of the intervention the toothing gets smaller again and finally disappears. During the phase of enlarging the working space 19, the latter runs past the inlet kidney 25 in the inlet region 26, so that the medium supplied at the inlet channel 23 is sucked into the relevant working space 19. During the phase of the reduction of the relevant working space 19, the latter runs in the outlet area 27 past the outlet kidney 28, so that the medium is pushed out to the outlet channel 24 via the outlet kidney 28. In this way, by the rotation of the housing member 8 and the Innenrotationsverdrängerelements 15 - ie at least one of Rotationsverdrängerelemente 5, 6 - a continuous pumping operation can be realized.

The Fig. 2 The rotary displacement pump 2 extends from a drive-side first end 31 along its longitudinal axis 32 to a pump-side second end 33. The longitudinal axis 32 is at the same time the axis of rotation 9 of the housing element 8 formed as the first Rotationsverdrängerelements 5. The wall portion 12 of the housing member 8 is integrally connected to a shaft 34 formed as a rotary member 35. The shaft 34 extends from the wall portion 12 of the housing member 8 to a clutch formed as a magnetic coupling 36. The clutch 37 is located in a fastened with mounting screws 38 on the pump housing 3 pump carrier housing 39. The shaft 34 is about two with respect to the axis of rotation 9 axially spaced bearings 40, 41 rotatably mounted in the pump housing 3. The bearings 40, 41 are radial bearings. The first bearing 40 is designed as a two-part angular contact ball bearing 42, the second bearing 41 is formed as a cylindrical roller bearing 43.

The magnetic coupling 36 consists of an outer magnet 44, which surrounds an inner magnet 45 ideally. The inner magnet 45 is rotatably connected via an associated hub 46 (magnetic hub) and a fastening screw 47 with the shaft 34. The hub 46 is centered by means of a centering pin 48 arranged between the hub 46 and the shaft 34. Between the outer magnet 44 and the inner magnet 45 a fixed to the pump housing 3 by means of fastening screws 49 cap 50 is arranged. The cap 50 separates a pump interior 51 of the pump housing 3, which also includes the receiving chamber 4, from an interior 52 of the pump carrier housing 39, in which the outer magnet 44 is located. The outer magnet 44 is rotatably connected to a magnetic carrier 53, which has a receptacle 54 for the output shaft of a drive motor, not shown. The drive motor is preferably an electric motor. When the shaft 34 is driven by the drive motor, the shaft 34 is a drive shaft of the driven rotary displacement element 5.

The eccentrically surrounded by the rotatably mounted housing member 8 Innenrotationsverdrängerelement 15 is rotatably mounted on a trained as a cylindrical roller bearing 55 bearings 56 on the pump cover 22 (housing cover). A corresponding bearing shaft 57, which is fixed by means of a fastening screw on the pump cover 22, has centering pins 58 for centering.

A bypass 59, which connects the outlet region 27 to the inlet region 26, runs in the pump interior 51 and thus permits a return of a portion of the medium from the outlet region 27 into the inlet region 26, independently of the delivery through the working chambers 19. The bypass 59 allows a volume flow of the medium along the following bypass path: Through a leakage channel, not shown, the refluxing medium from the outlet portion 27 of the receiving chamber 4 passes through the cylindrical roller bearing 55 associated with the Innenrotationsverdrängerelement 15 in a running within the shaft 34 channel 60 and through the Subsequently, the medium flows along the inner surface of the cap 50 back to the outer region 62 of the shaft 34, passes through an axial fixing 63 and arranged in the pump interior 51 two bearings 40, 41. Then flows the Medium on a mating surface 64 of the first Rotationsberdrängerelements 5 (housing member 8) along in an annular portion 11 of the housing member 8 surrounding outer region 62 of the receiving chamber 4. From there, the medium enters the inlet region 26 of the receiving chamber 4. The mating surface 64 d The first rotational displacement element 5 delimits the bypass 59, its counterface normal (arrow 65) having a component which is oriented opposite to the boundary surface normal (arrow 66) of the boundary surface 21.

In this embodiment, in the boundary surface 21 is an axial boundary surface 20, which limits the working spaces 19 axially. Furthermore, in this embodiment, the mating surface 64 is disposed opposite to the boundary surface 21.

This results in the following function of the bypass 59: Due to the opposite orientation of the surface normal (arrow 65) and the Begrenzungsflächennormalen (arrow 66) compensate for the resulting from the pressure of the medium in the working chamber 19 and the pressure in the bypass 59 axial forces on the opposite surfaces 21, 64 at least partially. As a result of the significantly reduced total axial force, the bearings 40, 41 designed as radial bearings can be made smaller and do not absorb high axial, but mainly radial forces.

The pressure inside the bypass 59 is by means of a in Fig. 3 shown valve 67 controllable and / or adjustable. This valve 67 is attached to the outer surface of the pump cover 22. It is fluidically arranged, for example, in the bypass 59 between the outlet region 27 and the leakage channel and serves to counter-pressure limiting. The valve 67 can be actuated externally and preferably has a sensor for determining a volume flow through the valve 67. By determining the volume flow at the valve 67, a variable backpressure can be generated, which can be regulated as required.

Alternatively, the valve 67 has a valve-internal mechanism which controls an in-valve control of the pressure difference Δp of the medium as a function of the pressure prevailing on the input side of the valve 67.

Furthermore, the forces resulting from the pressure difference Δp between the inlet region 26 and the outlet region 27 can also be adjusted, in particular reduced, by setting this pressure difference Δp by means of the valve 67 via the bypass 59.

By the coordinated unwinding of Rotationsverdrängerelemente 5, 6, so the housing member 8 or the Innenrotationsverdrängerelements 15, the medium promoted low in pulses. Furthermore, the medium is not squeezed the good coordination of the rolling function between the Einniere 26 and Auslassniere 28 in the lid 22.

The axial fixing 63 serves in one embodiment simultaneously as a diaphragm for reducing pressure and thus also the force reduction between the interior of the cap 50 and the pump interior 51 in the outer region 62 of the shaft 34th

The bypass 59 of the Fig. 2 shown pump 2 extends in a closed region of the pump 2, which extends in the direction of the longitudinal axis 32 from the pump cover 22 to the inner magnet 45 of the magnetic coupling 36 surrounding cap 50. The power transmission to the drive motor is effected by magnetic frictional connection between the inner magnet 45 within the closed area and the outside of this closed area arranged outer magnet 44 of the magnetic coupling 36. From the closed area is no rotatable relative to the pump housing 3 rotatably mounted part 35, such as the shaft 34, led out. This makes it superfluous to seal off the sealed area from its surroundings by means of a dynamic seal (moving seal), in particular a rotary seal, such as a shaft seal circumferentially surrounding the rotary part 35. The rotational displacement pump 2 is thus preferably a motion seal-free rotary displacement pump 68. A motion seal-free rotary displacement pump 68 is usable for maximum pressure of the medium at the inlet portion 26 and / or at the outlet portion 27, which is in a range above 20 bar, preferably in one Range above 50 bar.

In addition to the reduction of the axial forces, the bypass 59 also serves to cool the aforementioned components circulated and flowed through by it, ie the bearings 40, 41, 56, the shaft 34, the coupling 37, the pump interior 51 and the rotary displacement elements 5, 6 If the medium has sufficient lubrication properties, then the bypass 59 continues to serve for the lubrication of these components of the pump 2.

If the above-mentioned components 5, 6, 40, 41, 56, 34, 37, 51 circulated and flowing through the medium continue to be good low-wear components with high chemical resistance, the pump 2 is a pump 2 for delivering non-lubricating and / or corrosive media. The pump housing 3 and / or the shaft 34 consist, preferably of stainless steel (material No. 1.4404 or 1.4571) and / or Hastelloy (C-276, material No. 2.4819) and / or titanium (grade 2, material no 3.7035). The bearings 40, 41, 56 and / or the Rotationsverdrängerelemente 5, 6 are - at least in part - made of the materials Teflon and / or carbon and / or peek and / or non-seizing alloys (Non Galling Alloys). The non-seizing alloys do not weld with the stainless steel, Hastelloy, or titanium pump housing 3 and / or shaft 34 during operation of the pump.

LIST OF REFERENCE NUMBERS

1

gerotor

2

Rotary displacement

3

pump housing

4

receiving chamber

5

Rotationsverdrängerelement

6

Rotationsverdrängerelement

7

Verdrängerelementesatz

8th

housing element

9

axis of rotation

10

Hypotrochoidengehäuse

11

ring part

12

wall part

13

inner circumference

14

chamber

15

Innenrotationsverdrängerelement

16

outer periphery

17

tooth

18

axis of rotation

19

working space

20

Axialbegrenzungsfläche

21

boundary surface

22

pump cover

23

inlet channel

24

exhaust port

25

inlet kidney

26

inlet area

27

outlet

28

outlet kidney

29

arrow

30

arrow

31

first end

32

longitudinal axis

33

second end

34

wave

35

turned part

36

magnetic coupling

37

clutch

38

fixing screw

39

Pump support housing

40

camp

41

camp

42

Angular contact ball bearings

43

Cylindrical roller bearings

44

outer magnet

45

interior magnet

46

hub

47

fixing screw

48

Centering

49

fixing screw

50

cap

51

Pump interior

53

magnet carrier

54

admission

55

Cylindrical roller bearings

56

camp

57

bearing axle

58

Centering

59

bypass

60

channel

61

Cap interior

62

outdoors

63

cover

64

counter surface

65

Against surface normal

66

Limiting surface normal

67

Valve

68

Motor Seal Free Rotary Displacement Pump

Claims (15)

Rotary displacement pump (2) for pumping a medium, with a pump housing (3), - One in the pump housing (3) formed receiving chamber (4) having an inlet region (26) and an outlet region (27) and - At least one in the receiving chamber (4) recorded Rotationsverdrängerelement (5, 6) by means of at least one bearing (40, 41, 56) is rotatably mounted in the pump housing (3) and at least one boundary surface (21), with at least a working space (19) of the pump (2) limited,
marked by a bypass (59) which allows a portion of the pumped medium to flow back from the outlet area (27) into the inlet area (26),
wherein the Rotationsverdrängerelement (5, 6) and / or connected to the Rotationsverdrängerelement rotary member (35) has at least one counter surface (64) which limits the bypass (59) and whose Gegenflächennormale (65) has at least one component, which is opposite to the Boundary surface normal (66) of the boundary surface (21) is aligned. Rotationsverdrängerpumpe according to claim 1, characterized in that the limiting surface (21) is an axial boundary surface (20) which limits the working space (19) axially. Rotationsverdrängerpumpe according to any one of the preceding claims, characterized in that the counter-surface (64) opposite to the boundary surface (21) is arranged. Rotary displacement pump according to one of the preceding claims, characterized in that the bypass (59) has a valve (67) for controlling and / or regulating the flow of the back-flowing medium through the bypass (59). Rotationsverdrängerpumpe according to any one of the preceding claims, characterized in that one of the Rotationsverdrängerelemente (5) is designed as a housing member (8) which eccentrically surrounds a Rotationsverdrängerelement (6) formed as Innenrotationsverdrängerelement (15). Rotary displacement pump according to Claim 5, characterized in that the housing element (5) is designed as a hypotrochoid housing (10) with n chambers and the internal rotation displacement element (15) has n-1 corresponding teeth (17) for engagement in the chambers. Rotary displacement pump according to one of the preceding claims, characterized in that the rotary part (35) is a shaft (34) or has a shaft (34). Rotationsverdrängerpumpe according to claim 7, characterized in that the shaft (34) forms the bypass (59). Rotationsverdrängerpumpe according to any one of the preceding claims, characterized in that the Rotationsverdrängerelement (5) is driven by an associated drive motor Rotationsverdrängerelement (5). Rotary displacement pump according to claim 9, characterized by a coupling (37), in particular a magnetic coupling (36), which is arranged between the shaft (34) and the drive motor. Rotationsverdrängerpumpe according to claim 10, characterized in that the coupling (37) along the bypass (59). Rotationsverdrängerpumpe according to claim 4, characterized in that the valve (67) has a valve-internal mechanism for valve-internal control of the flow through the bypass (59) in response to a pressure prevailing on the input side of the valve (67). Rotationsverdrängerpumpe according to any one of the preceding claims, characterized in that the pump (2) is designed as a movement seal-free rotary displacement pump (68). Rotary displacement pump according to one of the preceding claims, characterized in that the pump housing (3) and / or the shaft (34) made of stainless steel and / or a Hastelloy nickel-based alloy and / or titanium. Rotationsverdrängerpumpe according to any one of the preceding claims, characterized in that the bearings (40, 41, 56) and / or Rotationsverdrängerelemente (5, 6) - at least in part - from the materials Teflon and / or carbon and / or Peek and / or consist of non-seizing alloys.

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