DE19735539A1 - Mixer for small-scale application - Google Patents

Abstract

Mixing is carried under air-tight conditions, in order to prevent contamination of pharmaceutical products, or for materials withdrawn intermittently which could be affected by contact with air. The mixing blades can be held in any location, normally a mixing and a rest position, in order to hold them in constant readiness. The base of the container, in the form of a piston, can be moved upwards to force the product out a dispensing opening in the lid whilst still being just below the mixing blade. A vane-type mixing blade is used. Vanes may be displaced alternately above and below the general rotation plane. The vanes could be spirals whose ends contact the container walls elastically. About half the subsidiary claims describe variations of the mixer blade assemblies and may be considered as independent claims.

Description

The invention relates to a device for stirring or Production of mixtures or the like in a stirred vessel with a through a lid and a bottom lockable circular cylindrical Interior and an agitator constantly enclosed in the mixing vessel stuff, as well as a lockable central implementation passable, are operatively connected to an electric motor Stirring rod for driving the stirring tool, which when closed Carrying releasably sits in a rest position and during the Stirring operation with the drive inserted into the mixing vessel end of the stirring rod is in drive connection.

US Pat. No. 4,735,509, which relates to a Dispensing tube for grouting cement. Located in the donor tube a cartridge with a plastic bag in which the components of the cement, namely a cement paste and a Catalyst are located, which are separated from each other by a partition are. The bag is tied at both ends.

A mixing arrangement, namely a, is located in the dispenser tube Agitator. The tube closes to the front through an outlet nozzle  and move backwards through a piston like inside the tube floor.

The mixing tool has a central slot in which the drive fits end of a stir bar which is inserted through the nozzle 16. The stir bar is connected to an electric motor or an electric one Drill connected, which sets the mixing tool in motion. If the agitator is moved in the longitudinal direction of the tube, it tears the stirring tool the plastic cover and mixes the components of the inventory stored separately in the plastic cover dividing the cement. When the stirrer is at the bottom of the tube arrived, the stir bar is removed and the arrangement in one Device inserted through which the piston into the tube is pressed so that the finished cement, but also the shredded Plastic sleeve can escape through the discharge nozzle.

This device is not only for single use, but apparently is only suitable for preparation of grouting cement from separately stored components.

There is no provision for air access at the mixing pro to avoid. In addition, that is by the known device caused mixing process not suitable, for example, ointments, Mixtures, suspensions or emulsions u. Like. Manufacture the are to be manufactured for medical or cosmetic applications.

The known device is not suitable, for. B. long ge stored, opened colors or the like in appropriate containers to make them usable or spreadable again. In the well-known The mixing tool remains after mixing the cement stock parts in its lower position on the piston-like sliding Sitting on the floor. It cannot be reactivated from this position become.

In contrast, the invention has for its object a device to train in the manner mentioned at the outset so that the mixture in  the remaining mixing tool can be used again at any time can be.

This object is achieved in that the dimensions the mixing vessel, the stirring tool and the drive end of the mixer Stabes are so matched to one another that the stirring tool when Insert the stirring rod into the mixing vessel from the clamp in the Detachable rest position and when it is returned from the mixing vessel can be clamped back into its rest position.

The device according to the invention is further constructed so that the components are mixed in the absence of air. Thereby Prevents airborne germs in the Penetrate the mix.

The mixing vessels can have practically any size. The Erfin manure can be combined with smaller mixing vessels, but also Connection with mixing vessels that contain color, for example, deploy. Developments of the invention can be the claims 2 to 29, the claims 2 to 12 to the device and claims 13 to 29 used as a mixing tool Wing stirrers are directed.

According to claim 2, the mixer - regardless of what type - a central to accommodate the drive end of the stir bar drive socket on the rest of the stirring tool with clamp seat in the central feed-through for the stir bar is stuck.

The connection between the drive end of the stir bar and the Mixing tool can by a clamp connection, but also by a Clip connection can be established.

According to claim 4, a so-called steep thread can also be used.

The stirring vessels according to the invention are in claims 5 to 9 featured. The mixing vessels can have a lid that  is integrally connected to the jacket of the mixing vessel. The floor is then designed as a displaceable piston in the mixing vessel. Either the lid firmly attached to the mixing vessel as well as the piston Like floors can have central passages for the stir bar.

A screw cap can also be used as the cover, which is the has central implementation for the stir bar. The resting position of the stirring tool depends on whether the central implementation is arranged in the lid or in the bottom, immediately below the Lid or immediately above the bottom.

The stirring tool has a central passage through which the Contents of the mixing vessel through the central implementation or through a special material outlet can be driven out in which the piston-like base is pressed into the mixing vessel.

The central implementation, regardless of whether it is on the lid or on the bottom arranged, can be connected to applicators through which both the contents of the mixing vessel, for example as a skin cream, can be applied to the sensitive area of the skin. Without to change something at the core of the invention, but can by certain Applicators also through the central passages or through the outlet openings are filled.

According to claim 10, the mixing vessel with a vertically back and forth Movable bracket can be connected, for example a guide slot is connected to the device and this moves back and forth mechanically in the vertical direction can be.

The reciprocating bracket can on the mixing vessel itself, however can also be arranged on the central passage of the mixing vessel.

According to claim 12, the mixing vessel can also be closed with more Openings.  

It is advantageous if a paddle stirrer is used as the stirring tool becomes. The inner areas of the impeller sit on a hub or on a drive socket and are crescent-shaped towards the end reach curved. The cross sections of the impeller can be quite be angular but also streamlined.

By the measures characterized in claims 17 to 19, especially in that the agitator blades successively under can be inclined differently, it is possible to make an intense through to achieve mixing of the mixture components. This mixture is further promoted by the fact that the mixing vessel during the stirring can be moved back and forth in the vertical direction. The End areas of the agitator blades are under frictional pressure on the inner wall of the mixing vessel. Also the front and back edges of the mixer wings are in their upper and lower end positions on the inside surfaces of the lid or the bottom, so that there is no mix can fix the inner walls of the mixing vessel.

According to claim 24, the paddle is a relatively flat disc educated. The paddle stirrer can be used in special embodiments also be firmly connected to the stir bar.

The constructive structure of the paddle stirrer used with advantage is characterized in claims 26 to 28.

A special form of the impeller is claimed in claim 29. With such a paddle, depending on the viscosity of the mix - advantageous mixing can be brought about.

Embodiments of the invention are described below with reference to the Drawing explained.

It shows  

Fig. 1 is a schematic side view of the apparatus,

Fig. 2 shows a cross section through a first mixing vessel,

Fig. 2a shows a detail of construction,

Fig. 3 shows a cross section through a second mixing vessel,

Fig. 4 shows a detail of construction,

Fig. 5 shows a cross section through a further Ausführungsbei play a mixing vessel,

Fig. 6 is a cross sectional view of another Ausführungsbei play a mixing vessel,

Fig. 7 shows a cross section through a further Ausführungsbei play a mixing vessel,

Fig. 8 is a detail of construction,

FIG. 8a schematically illustrates a coarse thread for connection between a stirring rod and a stirring tool,

Fig. 9 is a top view of a paddle,

Fig. 10 is a cross section along the line X / X in Fig. 9,

Fig. 11 is a side view of the cross section of a development of the paddle and

Fig. 12 shows a second embodiment of a paddle stirrer.

Fig. 1 shows schematically an apparatus 1 with a stand 2 and an electric motor 3 to which a stirring rod 4, a stirring tool 6 is connected within a mixing vessel. 5 The stirring vessel 5 may be of a holder 7 with the device 1 in Wirkver bond. The holder 7 can be arranged on the jacket of the stirring vessel 5 , but also on the central passage for the stirring rod 4 .

The holder 7 can be moved back and forth in a guide slot 8 in the direction of the double arrow in the vertical direction.

FIG. 2 shows the cross section of a first exemplary embodiment of a stirring vessel 11 with a circular-cylindrical jacket which ends at the bottom of a standing edge 13 . The circular-cylindrical jacket 12 is integrally connected to a cover 14 which has a central cover outlet 15 . This consists of a threaded shoulder 16 which is integrally connected to the cover 14 and is provided with an external thread 17 . A threaded plug 18 for closing the central cover exclusion can be screwed onto this external thread 17 . The central lid outlet 15 can, however, also be closed by a screw cap 20 ( FIG. 2a).

The threads 16 and 17 and the stopper 18 and the screw cap 20 are dimensioned so that a sufficiently airtight seal of the mixing vessel is ensured.

The stirring vessel 11 has a piston-like base 21 which is provided with an annular elastic side wall 22 and a lower edge 23 in order to ensure a tight seal of the piston-like base 21 within the stirring vessel 11 .

In the lower area, a clamping ring 24 (see FIG. 4) is provided, through which the stroke of the piston 21 is limited at the bottom.

The piston-like base 21 has a central passage 25 with a sealing guide 26 for the stirring rod 4 . The inside diameter 27 of the central bushing is dimensioned so that the stir bar 4 can rotate tightly within the central bushing 25 .

The central bushing 25 has an external thread 28 , onto which a screw cap 29 with an inner plug is screwed in the exemplary embodiment shown.

The schematically indicated stirring tool 30 has a drive nozzle 31 , in which a central passage 32 is provided through which the mixture is discharged from the mixing vessel 11 when the piston-like base 21 is pressed upwards.

The stirring tool 30 is shown in its rest position 34 in the immediate vicinity above the piston-like base 21 .

After removing the screw cap 29 , the stirring rod 4 can be inserted and connected to the drive socket 31 of the stirring tool 30 in a manner explained later. The connection is made that not only a drive rotation movement can be exerted on the stirring tool 30 by the stirring rod 4 , but also a back and forth movement in the direction of the double arrow 9 in FIG. 1.

The piston crown 21 has a secondary passage with a plug 36 , through which material can optionally be introduced into the mix.

Without changing anything at the core of the invention, auxiliary connections in the manner of auxiliary connection 35 can also be arranged in the circular cylindrical jacket wall 12 , but also in the cover 14 of the mixing vessel 5 . This also applies to all further described exemplary embodiments of the invention.

Fig. 3 shows schematically a stirring vessel 38 , with a circular-cylindrical jacket 39 , which closes at the bottom by a stroke limiting ring 40 , which is also used as a standing ring for the stirring vessel 38 .

The stirring vessel 38 is connected to a screw cap 41 , the inner wall of which is designated 41 a. A central bushing 42 with an external thread 43 is arranged in the screw cap 41 . The central passage 42 has a sealing guide 44 for the stirring rod 4 .

The stirring vessel 38 is equipped with a piston-like base 45 , which can be moved upwards in the direction of the arrow. The piston-like bottom 45 has an annular elastic Seitenwan extension 46 .

The schematically indicated stirring tool 47 is connected to the drive end of the stirring rod 4 in a manner explained later.

The mixing vessel 49 of FIG. 5 is integrally connected to a cover 14 in which is located a central grommet 50.

The stirring tool 13 is shown in its rest position 51 arranged directly below the cover 14 . It has a central passage 32 through which the mixture can be discharged from the piston 21 . A stirring vessel 52 according to FIG. 6 has a cover 14 which is integrally connected to the cylindrical jacket wall 12 . The bottom is designed as a piston 21 with a central passage for the stir bar. The stirring tool 30 has a drive socket 31 , in which the drive end of the stirring rod 4 is clamped.

The stirring tool 30 is shown in its rest position 52 immediately above the piston-like base 21 .

A stirring vessel 54 according to FIG. 7 has a screw cap 41 and has a piston-like bottom 45 , next to which the stirring tool 47 is in its rest position. The central bushing 55 is arranged on the bottom 45 .

Fig. 8 shows schematically parts of the screw cap 41 with an inner wall 41 a and a central passage 42 which has an external thread 43 for a screw cap or the like.

The inner diameter 27 of the central bushing is set to the outer diameter 33 of the drive end 56 of the stirring rod and the outer diameter 33 of the drive nozzle 31 so that a tight stirring operation is ensured.

The stirring tool 47 has a drive socket 31 , in which the drive end 56 of the stirring rod is shown by means of a releasable connection 85 .

The drive socket 31 is clamped in the central passage 42 by means of a clip connection 57 . This clip connection has at the lower end of the central bushing 42 an annular bead 58 , which an annular snap groove 59 in the drive neck 31 is opposite. This ensures that the stirring tool 47 is firmly seated in its rest position

Fig. 8a shows a detachable connection between the drive end 56, 87 and the drive bushing 31 of a stirring tool 47th The parts of the high-helix thread 37 and 37 a inside the drive socket and in the outer wall of the drive end 56 , 87 of the stirring rod 4 , 86 allow a relatively secure connection between the stirring rod 4 , 86 and the stirring tool 47 during the rotation of the stirring rod to produce, which can be easily solved by rotating in opposite directions after the end of the rotation.

The invention can work with any suitable stirring tool which settle in the rest position within the mixing vessel leaves and which with the drive end of the stir bar for the duration the mixer can make a secure connection.

Fig. 9 shows the top view of a preferred exemplary embodiment of a stirring tool. It is a paddle stirrer 61 with agitator blades 62 , the inner regions 64 of which extend crescent-shaped from a hub 65 to the outside. Instead of the hub 65 , a drive connection 31 can also be provided without changing anything at the core of the invention.

The end regions 63 of the agitator blades 62 lie under frictional pressure on the jacket 88 of a mixing vessel, which is indicated mathematically. Between the stirring blades, intermediate pieces 80 are provided which are connected to a connec tion ring 82 . The connecting ring 82 is located at a distance 83 from the end regions 63 of the impeller 62 .

FIG. 10 schematically shows a section along the line X / X in FIG. 9. The stirring rod 86 is fixedly connected at its lower end 87 to the paddle stirrer 61 designed as a flat disk 84 according to FIG. 9. The intermediate pieces 80 are indicated in cross section.

10 is clearly shown in Fig. Recognized that the end portions 63 abut the agitating wing 62 on the inner wall 89 of the sleeve 88..

It should be noted that FIG. 10 schematically represents a section through the paddle stirrer 61 according to FIG. 9. It is assumed that the cutting line is guided along the impeller.

Fig. 11 shows schematically a development of the circumference of the blade stirrer according to Fig. 9. The stirring blades are shown in section. 77 shows an impeller with a rectangular cross section. The direction of rotation of the impeller shown schematically is indicated by arrow 71 . The agitator blades with streamlined cross sections are preferred.

A distinction is made between impellers with an inclination direction, the leading upper edges 66 of which lie in an upper outer plane 73 . The trailing lower edges 67 of these impellers lie in a lower inner plane 76 .

The agitator blades inclined in the other direction lie with their outgoing lower edges 68 in a lower outer plane 74 and with their trailing upper edges 69 in an upper inner plane 76 . The agitator blades are inclined at an angle of 70 or 72 relative to the horizontal.

A sharp edge 79 is shown on the impeller with a rectangular cross section 77 , which scrapes off the material to be mixed from the inner wall 91 of the base 19 . The other impellers can also be provided with such a sharp edge. Often, however, it is also sufficient that there is frictional contact only with the inner wall 91 of the bottom 90 or the inner wall 93 of the cover 92 . The levels 73 and 75 and the corresponding other levels are at a distance 81 from one another, which depends on the mix to be processed. Likewise, the angle of inclination will depend on the mix to be processed.

Fig. 12 shows a plan view of another example of a Ausfüh approximately a paddle, which consists of an outer paddle 94 and an inner paddle 97 . The outer paddle has long paddle 95 . In Fig. 12 two long impellers 95 are shown. A plurality of outer stirring blades 95 can also be used. The end regions 96 of these long stirring blades 95 rest against the inner wall of the mixing vessel under frictional pressure. The short stirring blades 98 of the inner blade stirrer end at a distance 101 from the end regions 96 inwards. As can be seen in FIG. 12, several short impellers 98 are provided. Their ends 99 are connected to one another by means of a ring 100 .

The paddle stirrers 61 or 94 and 97 not only ensure an optimal mixing of the material to be mixed, but also take up only a small space within the mixing vessel. All paddles can be locked in their rest positions. They can be used again at any time to process the mix within the mixing vessels or to mix from scratch.

Reference list

1

contraption

2nd

Stand

3rd

Electric motor

4th

Stir bar

5

Mixing vessel

6

Agitator

7

bracket

8th

Guide slot

9

Double arrow

10th

11

Mixing vessel

12th

circular cylindrical jacket

13

Standing edge

14

with the cover one-piece lid

15

central cover outlet

16

Thread approach

17th

External thread

18th

Plug

19th

20th

Screw cap

21

piston-like bottom

22

annular elastic side wall

23

lower edge

24th

Clamping ring to limit the stroke

25th

central implementation

26

sealing guide of the stir bar

27

Inside diameter

28

External thread

29

Screw cap with inner plug

30th

Agitator

31

Drive socket

32

central passage

33

outer diameter

34

Resting position

35

Secondary passage

36

Plug

37

Steep thread

37

a steep thread

38

Mixing vessel

39

circular cylindrical jacket

40

Stroke limiting ring

41

Screw cap

41

a inner wall

42

central implementation

43

External thread

44

sealing guide for stir bar

45

piston-like bottom

46

annular elastic side wall

47

Agitator

48

49

Mixing vessel

50

central implementation

51

Resting position

52

Mixing vessel

53

Resting position

54

Mixing vessel

55

central implementation

56

Drive end of the stir bar

57

Clip connection

58

Ring bead

59

annular snap groove

60

61

Paddle stirrer

62

Impeller

63

End area

64

inner area

65

hub

66

preceding upper edge

67

trailing bottom edge

68

preceding lower edge

69

trailing upper edge

70

Angle of inclination

71

Direction of rotation

72

Angle of inclination

73

upper outer level

74

lower outer level

75

upper inner level

76

lower inner level

77

rectangular cross section

78

streamlined cross section

79

sharp edge

80

Spacer

81

distance

82

Connecting ring

83

distance

84

flat slice

85

Detachable connection

86

Stir bar

87

lower end

88

Sheath of the mixing vessel

89

inner wall

90

ground

91

Interior wall

92

cover

93

Interior wall

94

outer paddle

95

long impeller

96

End area

97

inner paddle

98

short impeller

99

The End

100

ring

101

distance

Claims (29)

1.Device for stirring or producing mixtures or the like in a stirring vessel with a circular cylindrical interior which can be closed by a lid and a bottom and a stirring tool which is constantly enclosed in the stirring vessel, and also in operable connection with an electric motor which can be passed through a closable central passage a stationary stirring rod for driving the stirring tool, which, when the feedthrough is closed, is releasably in a rest position and is rotationally connected to the drive end of the stirring rod inserted into the stirring vessel during the stirring operation, characterized in that the dimensions of the stirring vessel ( 5 , 11 , 38 , 49 , 52 , 54 ), the stirring tool ( 6 , 30 , 47 , 61 , 94 , 97 ) and the drive end ( 56 , 87 ) of the stirring rod ( 4 , 86 ) are coordinated so that the stirring tool when inserting the stirring rod into the Stirring vessel from the clamp in the rest position l is releasable and can be clamped when it is returned from the mixing vessel back to its rest position. 2. Device according to claim 1, characterized in that the stirring tool ( 39 , 47 , 61 , 94 , 97 ) for receiving the drive end ( 56 , 87 ) of the stirring rod ( 4 , 86 ) has a central drive nozzle ( 31 ), which sits in the rest of the stirring tool ( 30 , 47 , 61 , 94 , 97 ) with a clamp in the central bushing. 3. Apparatus according to claim 2, characterized by a clip connection ( 57 ) between the drive socket ( 31 ) and the central implementation. 4. The device according to one or more of claims 1 to 3, characterized in that the drive end ( 56 , 87 ) of the stirring rod ( 4 , 86 ) and the inner shell of the drive socket ( 31 ) or the hub ( 65 ) are components of a high-helix thread ( 37 , 37 a), which is attracted by the rotation of the stirring rod ( 4 , 86 ), and that after the return of the stirring tool ( 47 ) to its rest position ( 34 , 51 , 52 ) by counter-rotation from the hub ( 65 ) or the drive socket ( 31 ) can be removed. 5. Device according to one or more of the preceding claims, characterized in that the cover ( 14 ) is a one-piece component of the mixing vessel ( 49 ) and with the central passage ( 50 ) that the rest position ( 51 ) of the stirring tool ( 30 ) is located immediately below the cover ( 14 ), and that the bottom ( 21 ) of the stirring vessel ( 49 ) is designed as a piston ( 22 , 23 ) which can be displaced in the stirring vessel. 6. The device according to one or more of claims 1 to 4, characterized in that the cover ( 14 ) is an integral part of the mixing vessel ( 11 ), that the bottom ( 21 ) as in the stirring vessel ( 11 ) displaceable piston ( 22 , 23 ) is formed and provided with a central passage ( 25 ), and that the rest position ( 34 ) of the stirring tool ( 30 ) lies directly above the bottom ( 21 ). 7. The device according to one or more of claims 1 to 4, characterized in that the lid ( 14 ) integral part of the mixing vessel ( 11 ) and with a closable material outlet ( 15 ) is provided that the bottom as in the mixing vessel ( 11th ) displaceable piston ( 21 ) is formed and provided with the central passage ( 25 ), and that the rest position ( 34 ) of the stirring tool ( 30 ) lies directly above the bottom ( 21 ). 8. The device according to one or more of claims 1 to 4, characterized in that the lid for the mixing vessel ( 38 ) is screw cap ( 41 ), and has a central passage ( 42 ), and that the bottom ( 45 ) than in the mixing vessel ( 38 ) displaceable piston is formed, and that the rest position ( 52 ) of the stirring tool ( 30 ) is immediately below the cover ( 41 ). 9. Device according to claims 1 to 4, characterized in that the lid for the mixing vessel ( 54 ) is a screw cap ( 41 ), that the bottom as in the mixing vessel ( 54 ) displaceable piston ( 45 ) is formed and with a central Implementation ( 55 ) is provided, and that the rest position ( 53 ) of the agitator tool ( 47 ) is immediately above the bottom ( 45 ). 10. The device according to one or more of the preceding claims, characterized in that the stirring vessel ( 5 , 11 , 38 , 49 , 52 , 54 ) with a vertically ( 9 ) reciprocating holder ( 7 ) can be connected. 11. The device according to claim 15, characterized in that the outer casing of the central bushing ( 15 , 25 , 42 , 50 , 55 ) with the vertically ( 9 ) movable holder ( 7 ) is connected. 12. The device according to one or more of the preceding claims, characterized in that the lid ( 14 , 41 ) and / or in the bottom ( 21 , 45 ) or in the wall ( 12 , 39 ) of the stirring vessel ( 5 , 11 , 38 , 49 , 52 , 54 ) in addition to the central passage ( 15 , 25 , 42 , 50 , 55 ) for the stirring rod ( 4 , 56 , 87 ) at least one further closable opening ( 35 , 36 ) is provided. 13. The device according to one or more of the preceding claims 1 to 12, characterized in that the stirring tool is a wing stirrer ( 61 ). 14. paddle stirrer according to claim 13, characterized in that the inner regions ( 64 ) of the agitator blades ( 62 , 95 , 97 ) sit on a hub ( 65 ) or on a drive connection piece, and therefore securely in the shape of the end regions ( 63 , 96 ) are shaped. 15. paddle stirrer according to claims 13 and 14, characterized in that the cross sections ( 77 ) of the agitator blades ( 62 , 95 , 98 ) are rectangular. 16. paddle stirrer according to claims 13 and 14, characterized in that the cross sections ( 78 ) of the impeller blades ( 62 , 95 , 98 ) are streamlined. 17. paddle stirrer according to claims 13 to 16, characterized in that the stirring blades ( 62 , 95 , 98 ) are alternately inclined in the direction of rotation ( 71 ). 18. Paddle stirrer according to claims 13 to 17, characterized in that the upper or lower edges ( 66 , 68 ) of the same direction of the stirring blades ( 62 or 98 ) respectively in the direction of rotation ( 71 ) respectively outer upper or lower levels ( 73 , 74 ) lie. 19. paddle stirrer according to claims 13 to 18, characterized in that the trailing in the direction of rotation ( 71 ) upper and lower edges ( 67 , 69 ) rectified impeller ( 62 and 98 ) each in inner upper and lower planes ( 75 , 76 ) are located at a distance ( 81 ) to the adjacent outer plane ( 73 , 74 ). 20. Paddle stirrer according to one or more of claims 13 to 19, characterized in that the from the hub ( 65 ) or from the drive nozzle crescent-shaped outgoing impeller ( 62 ) of the paddle stirrer ( 61 ) are designed such that their Endbe rich ( 61 ) rest under frictional pressure on the inner wall of the mixing vessel and thereby fix the paddle stirrer ( 61 ) in its rest position. 21. The device according to one or more of the preceding claims 13 to 20, characterized in that the paddle stirrer ( 61 , 94 , 97 ) in alignment with the central passage ( 15 , 25 , 42 , 50 , 55 ) has a central passage ( 32 ) for dispensing mixed material. 22. Paddle stirrer according to one or more of the preceding claims, characterized in that the outer upper and lower levels ( 73 , 74 ) in the upper and lower position of the paddle stirrer ( 1 , 94 , 97 ) with the inner wall of the lid or Make frictional contact with the inner wall of the floor. 23. A paddle stirrer according to one or more of the preceding claims, characterized in that the edges of the impeller blades ( 62 , 95 , 98 ) preceding in the direction of rotation ( 71 ) are formed as sharp edges ( 74 ). 24. paddle stirrer according to one or more of the preceding claims, characterized in that it is formed out as a flat disc ( 84 ). 25. paddle stirrer according to one or more of the preceding claims, characterized in that it is firmly connected to the stir bar.   26. Paddle stirrer according to one or more of the preceding claims, characterized in that the agitator blades ( 62 ) are connected to one another by intermediate pieces ( 80 ). 27. Paddle stirrer according to one or more of the preceding claims, characterized in that the intermediate pieces ( 80 ) between agitator blades ( 62 ) are formed as parts of a connecting ring ( 82 ). 28. Paddle stirrer according to claim 27, characterized in that the connecting ring ( 82 ) is arranged at a distance ( 83 ) from the end regions ( 63 ) of the stirring paddles ( 62 ). 29. Paddle stirrer according to one or more of the preceding claims, characterized in that an outer paddle stirrer ( 94 ) with long impeller blades ( 95 ) and an inner paddle stirrer ( 97 ) with short impeller blades ( 98 ) is connected to the drive socket or to the hub , and that the outer paddle stirrer ( 94 ) has at least two sickle-shaped agitator blades ( 93 ), the end regions ( 96 ) of which rest under frictional pressure on the inner wall of the mixing vessel, and that the inner paddle stirrer ( 97 ) includes short sickle-shaped agitator blades ( 98 ), the Ends ( 99 ) at a distance ( 101 ) from end regions ( 96 ) of the long stirring blades ( 95 ) are connected to one another by a ring ( 100 ).