EP1828608A2

EP1828608A2 - Compact eccentric screw pump

Info

Publication number: EP1828608A2
Application number: EP05818999A
Authority: EP
Inventors: Helmuth Weber
Original assignee: Netzsch Pumpen and Systeme GmbH
Current assignee: Netzsch Pumpen and Systeme GmbH
Priority date: 2004-12-15
Filing date: 2005-12-14
Publication date: 2007-09-05
Also published as: WO2006063583A3; DE102004060222A1; WO2006063583A2; KR20070091193A; BRPI0515744A; CN100554688C; DE112005003467A5; JP2008523314A; US7465157B2; KR100929070B1; CN101120173A; US20070253852A1

Abstract

The invention relates to a compact eccentric screw pump comprising a sliding articulation. The long-lasting operation of the pump is ensured by a plurality of functions. According to the invention, both the reaction pressure resulting from the transport pressure and the concomitant phenomena emerging from the eccentrically rotating rotor and acting on the articulation and the drive are approximately equalised.

Description

Progressive cavity pump in compact design

The invention relates to an eccentric screw pump having a stator with a helical cavity and an eccentrically arranged therein helical rotor, wherein on one side of the stator, a connection part and on the other side a pump housing is arranged, which surrounds at least one joint and a bearing in itself.

State of the art

An eccentric screw pump of this type with a sliding joint and arranged in the same housing storage is shown in DE OS 1653864 Al. However, this very compact eccentric screw pump has the disadvantage that, despite the arrangement or displacement of Ansaugöffhung in the stator, which is referred to as a short-coupling joint, with the respective product being pumped, comes into contact and thereby increasingly polluted. In addition, this close coupling is subject to the back pressure, which builds up on the pressure-side end of the pump and thus transmits via the rotor to the clutch. The short coupling can also be referred to as a joint, since it creates the compensation of the eccentric rotor rotational movement to the central rotational movement of the drive shaft.

From DE OS 20 57 860 an eccentric screw pump, in particular for conveying flow manure is known. In this pump sits on the drive shaft, a guide disc. This disc is guided at its two end faces on stationary flat surfaces. The full pressure, which is transmitted from the pressure side of the stator via the rotor to these surfaces, acts on these plane surfaces. This creates friction on the flat surfaces which leads to undesirable frictional resistance and heat. To overcome the friction, an increased drive power is required. DE 78 29 371 Ul discloses in Fig. 1, an eccentric screw pump with a magnetic coupling between the drive and a balance shaft. The coupling has a canned pot, which has the desired tightness of the pump to the outside, if toxic or environmentally harmful substances are pumped. To maintain the functionality of the clutch by keeping the gap geometries constant Aixalschubausgleich is effected within the clutch.

task

The object of the invention is to avoid impairments of the joint connection and storage in compact pumps and to reduce the drive power.

The problem is solved with the features of claims 1, 36, 40 and 51.

Advantageous further developments according to the invention emerge from the features of the subclaims.

Description of the invention

An exemplary embodiment of the invention relates in particular to a compact pump. Compact pump, therefore, because this pump achieves a very short construction by the use of a so-called sliding joint. The length of the pump housing is here only a small part of the total pump length, if one compares the usual lengths when using double universal joints or elastic bending rod connections.

The invention assumes that the optimum design of the invention is embodied by the fact that the stator and the joint area are spatially separated by a seal and that the joint before or assigned to a device which avoids an axial offset of the rotor caused is caused by the backpressure on the pressure side of the rotor / stator unit during the pumping process.

This device is advantageously placed to increase its effectiveness and to avoid contact with the product between the joint and a seal, preferably a mechanical seal placed. In this case, this arrangement between the joint and the mechanical seal is independent of whether the back pressure builds up at the free end of the stator or in the region of the rotor head.

For detecting the pressure acting on the rotor, regardless of whether this is done on the suction or pressure side of the stator, in each case a switching element for detecting the pressure value is arranged in these areas. It may be a membrane or an electrical / electronic pressure sensor, the

detected hydraulic pressure and then supplied to a device with the appropriate pressure, so that the pressures equalize at least, which means that the joint, the seal and the shaft of the drive can be operated axially unloaded and thus independent of delivery pressure.

According to a preferred embodiment of the invention, a mechanical seal is used as the seal. This seal sits on a larger rotor shaft cross-section compared to the rotor. The sliding ring of the seal can thereby compensate for a greater axial tolerance and is provided with an elastic bellows.

The hydraulic and mechanical forces acting on the rotor or extension of the rotor are balanced by means advantageously located between the joint and the seal.

According to a further development of the invention, the device consists of two radially spaced axially spaced support discs, which are arranged as a function of the length of a spacer tube from each other. Ln intermediate space of the support disks is a central disc whose width is smaller than the length of the spacer tube. Between the peripheral surface of Middle disc and the inside of the Distanzrolires a pressure medium space is limited. The pressure medium chamber is connected via a bore in one of the support disks and via a pipe to the respective pressure side of the stator / rotor in connection.

In an advantageous further embodiment of the invention, the middle plate on its end faces seals in the direction of the support discs. These seals are arranged at different radial distances from the longitudinal axis of the rotor or the pump. Due to the difference in length of the spacer tube and the width of the central disc, the pressure medium on the pressure side of the stator under pressure forms a gap between the central disc and the support discs. The surfaces which limit the gap are dependent on the radial distance of the seals to the pump or rotor longitudinal axis. This creates Drackflächen on the corresponding center disc on which the pressure medium acts.

According to an advantageous embodiment of the invention is dependent on the respective direction of rotation of the rotor pressure side of the pump via a pipe to the pressure medium space in connection. This results in a hydraulic pressure transmission which results in that the pressure in the pressure medium space between the central disk and the support disk forms a gap. The measures provided for at the end faces of the central disc radial different arrangement of the seals thus determines the side of the central disc at which forms a gap. Depending on which at which end of the middle plate, the seal is closer to the central axis of the pump, this gap is formed with a pressure surface which is larger than that on the opposite side of the central disc. When a backpressure occurs at the free end of the eccentric screw pump, the arrangement of the seals must be chosen so that the gap is formed on the hinge side facing the center disc. When reversing the direction of rotation, a middle plate is used in which the sealing combination is selected such that the liquid gap arises on the side of the middle plate, which points in the direction of the mechanical seal.

In a further advantageous embodiment of the invention, the pipeline is part of the stator and the pump housing. A further advantageous embodiment of the invention is to compensate for a pressure difference between the effective pressure surface on the central disc and the pressure surface on the rotor. Should this difference be smaller due to structural conditions in the area of the pressure medium space, it is proposed according to the invention to increase the pressure in the pressure medium space between the support disks.

According to a further embodiment of the invention, the pressure at the respective end of the stator is tapped by electrical or electronic pressure sensors and passed to the control of a storage container under pressure, passed. According to the determined pressure value of the reservoir tank pressure medium in the pressure fluid chamber.

According to a further development of the invention, the compensation pressure must be applied to the rotor, be generated by an additional hydraulic unit or mechanically via a servo motor.

According to a development of the invention, the pressure fluid and the blocking agent liquid for the mechanical seal of the same substance.

A further development of the invention provides that the position of the support disks are fixed by a plurality of different length spacers, which bear against the inside of the pump housing.

The progressing cavity pump is operated according to the invention by a method in which a measuring unit is arranged on the pressure side of the pump which detects the pressure present at the end of the rotor-stator unit, which builds up as a reaction pressure to the delivery pressure and is dependent on various factors. The friction in the pipeline, consistency of the product, flange cross-section and other criteria are considerable. This reaction pressure value is now either transmitted hydraulically directly into the seal-bearing hinge area and used to apply back pressure to the rotor itself or its associated parts for pressure equalization. In a direct hydraulic connection between the pressure and suction side of the eccentric screw pump equalization of the pressure gradient is achieved.

If an external pressure source is used, the pressure on the rotor in the suction-side region can also be slightly increased. If the pressure on the pressure side of the pump detected electrically / electronically, it can be dispensed with a hydraulic coupling of the pump pressure side with the joint area.

An additional development of the invention relates to the detection of the pressure value, which results as a back pressure to the delivery pressure. This pressure can, as already mentioned, measured in the region of the pressure-side free end of the stator and be passed not only by hydraulic means, but by electrical / electronic seals

Another measuring device according to the invention consists of strain gauges, which are connected directly to the rotor or the rotor head or the shaft between the rotor and the joint. With these measuring devices, the counter-pressure acting on the rotor is detected in the form of a resulting axial displacement.

Due to this positional deviation of the rotor, a back pressure is generated and causes a position compensation.

Embodiments of the invention are explained with reference to the following drawings.

Another approach to the problem is to relieve the seal and the joint from the effects of the eccentric rotating rotor.

According to the invention, this is done by the rotor head or a rotor extension in the region between the support ring, which is part of the mechanical seal and the rotor has at least one diameter reduction. By this one or more diameter reductions are already in the area of the rotor before the Gasket deflections generated by the rotor, reduced, whereby a more even investment of the sliding ring / s on the sealing disc is made possible.

Depending on which products and capacities the pump is designed for and which materials are used, the diameter or the diameter reductions can be chosen differently. Thus, the diameter reductions can have a value of 30% to 80% of the value of the diameter of the rotor.

In the case of special (wear-resistant) materials, it may be advantageous if not only one diameter reduction, but several with different reduction values are provided. In this case, the axial distances of the diameter reductions move between two to ten times the value of the respective diameter reduction. If the diameter is thus reduced to 10 mm, the next reduction can be arranged at a distance of 20 mm to 100 mm from the first one.

To improve the functioning of the mechanical seal and its sealing by the bellows, the area of the rotor head or the rotor extension, on which the bellows or the spring are mounted, assume a value which is greater than the rotor diameter. The corresponding rotor head or the rotor extension part here has a 1.2 to 2 times the value of the rotor diameter.

In special cases of use of the pump according to the invention a double-sided mechanical seal will be used to prevent entry of product into the storage area and an entry of lubricant into the pump chamber.

In the eccentric screw pump according to the invention, the seal between the pump inlet housing and the pump lantern is arranged, in which the joint is seated. Under certain conditions, it is advantageous if the width of the constrictions or diameter reductions in the region of the rotor is greater by at least 20% than in the region of the sealing disk. It shows:

Fig. 1 longitudinal section of an eccentric screw pump

Fig. 2 partial view of an eccentric screw pump

Fig. 3 partial view of an eccentric screw pump

Fig. 4 partial view of an eccentric screw pump

Fig. 5 partial view of an eccentric screw pump

Fig. 6 partial view of an eccentric screw pump

figure description

FIG. 1 shows an eccentric screw pump 10 which has a rotor / stator region 12, a pump housing 14 and a drive 16. At the left end of the illustrated eccentric screw pump sits a flange 18 which is braced by tie rods 20 to the pump housing 14 and thus also connects the stator 22 arranged therebetween firmly with the pump housing. The

Eccentric screw pump stands on the two connected to the flange and the housing feet 24. The cross section of the rotor head 26 and the extension of the rotor 28 is reinforced in the region of the inlet 30. In this area sits on the rotor, a mechanical seal 32 with a sliding ring 34 which bears against the left of the two support disks 36, 36 '. A seal, here a mechanical seal 32 and the sliding ring 34 follows the eccentric rotational movement of the rotor 28. To compensate for an angular displacement and a possible axial play of

Rotor 28, the slide ring 34 is provided with an elastic bellows 38.

Between the two support disks 36, 36 'moves a central disk 40 in the radial direction, according to the eccentricity with which the rotor head 26 rotates. The middle plate 40 sits on a spherical roller bearing 42 and thus does not rotate itself, but can only be movable in the axial direction via the spring rings which connects the center plate, the bearing and the rotor. Although the axial rotor displacement may be possible, this is prevented by means 46. This device consists of several components together, of which the middle plate 40 plays an essential role. The width of the center disk 40 and the width of the pressure medium chamber 48 are not equal. The width of the pressure medium chamber 48 is determined by the length of the spacer tube 50 and is deliberately chosen so large that between the right support plate 36 'and the end face of the center plate, a gap is formed in the hydraulic pressure comes into effect. The pressure which works in the pressure medium space and thus between the central disk 40 and the support disk 36 'depends on the pressure value which prevails in the interior of the pressure-side flange 18. The value of this pressure is dependent on the counter pressure generated by the delivery pressure. A diaphragm in the flange 18 decreases this value and transfers it to a liquid in the pipeline 52, which communicates with the liquid in the pressure medium chamber 48. Thus, in the region of the flange 18 at the end face of the free end of the rotor and in the region of the central disk, ie at the joint end of the rotor, equal pressure conditions.

The balance of the pressure conditions or an increase in the pressure between the middle plate 40 and the support plate 36 'relieves the sliding joint 44, so that it is operated pressure-free. The hydraulic connection between the pressure-side flange 18 and the pressure medium chamber 48 is a pipe 52 which is connected to the pump housing 14 in the region of the support disk 36. The hydraulic connection between the interior of the pipe 52 and the pressure medium chamber consists both of a radial and an axial bore in the support disk 36th

The bearing and the hinge area are connected to each other via a bore in the support disk 36 '. Through this hole, the end of the directly connected to the sliding joint 44 rotor head extends 26. The second part of the

Sliding joint is rotatably on the sleeve 56 but axially displaceable over a

Parallel key attached to the drive shaft 54. Just like the distance between the

Support discs 36, 36 'is predetermined by the spacer tube 50, as the distance between the support plate 36 and the housing flange 58 of a spacer tube

60 ..

Fig. 2 shows an embodiment of the invention in which the rotor is driven in the clockwise direction. Here arises the counterpressure acting on the rotor, which leads to a increased load of the sliding joint 44 could not lead to the free end of the rotor 28, but in the pump housing in the region of the mechanical seal and the pump outlet. As a result, the hydraulic pressure equalization takes place between the partial area of the pump housing and the pressure medium space (48). For this purpose, only a short U-shaped pipe 52 'is needed. This short hydraulic, as well as the leading to the free pump end connection can be made directly in the pump housing wall or the stator via a longitudinal bore to the pressure medium chamber. The pressure of the product acting on a membrane 64 is propagated via the liquid in the pipeline to the liquid present in the pressure medium chamber 48. Unlike in the left-hand rotation, a narrow gap is formed in this exemplary embodiment between the end face of the center disk 40 and the support disk 36, so that the rotor is subjected to a pressure in the direction of the sliding joint. The gap length and thus the size of the end face of the central disc, which in this case generates the back pressure, depends on the radial distance of the seals to the longitudinal axis of the rotor 28. The smaller the distance to the axis of the rotor, the larger the effective drag area. In order to prevent that also forms a pressure medium gap on the other side of the center plate, the seal is here even larger and arranged at a greater distance from the rotor axis near the outer periphery of the central disc. In sum, the area at which the pressure medium acts on the central disk must be equal to or greater than the sum of the areas acted on at the rotor of the conveyor back pressure.

In the embodiment shown in Fig. 3, the structure of the device 46 is illustrated. Here is the middle plate 40 in the lowest position. The arrangement of the differently dimensioned seals 66, 68 alone shows, on which side of the middle plate by the pressure medium, a gap is formed. The size of the finally acting pressure surface 70 is determined by the distance of the seal 66 to the longitudinal axis 76 of the rotor 28 and rotor head 26. The pressure medium in the pipe 52 'thus exercises on the Bore 74 and the pressure medium chamber 48 pressure on the pressure surface 70, 72 and thus compensates for the resulting during the pumping pressure difference, which otherwise lead to an axial displacement or load of the pump parts connected to the rotor would. The pressure surfaces 70, 72 of the center disk 40 and / or the complementary surfaces of the support disks 36, 36 'are themselves made of wear-resistant material or coated therewith.

The exemplary embodiment according to FIG. 4 shows a compact pump with a joint, in this special embodiment a sliding joint 92. Although the sliding joint 92 is able to convert the eccentric circulation movement caused by the rotor into a centric one over a very short distance, an attenuation of the oscillating circulation movement by a diameter reduction 90 is already effected in the area of the mechanical seal 88. This first diameter reduction 90 gives the rotor extension a higher elastic behavior and thus transmits a lower angular load on the hinge 92. The locking means to be entered via the radial bore 78 of the sealing washer 82 fills the area of the mechanical seal as well as the space 98 in which the sliding joint 92 is arranged is. By means of the central bore 94 located in the sliding ring extends the rotor extension, which consists of the rotor head 26 and the projection 96. The lug 96 communicates at its right end with a portion of the sliding joint 92, from which the driving force is transmitted to the rotor 28. In the region of the central bore 94, the rotor head 26 adjoins the diameter reduction, which presents itself as a constriction or as a notch. On the rotor head sits a clamping piece 100 on which both the spring 102 and a bellows 104 is held. The bellows 104, which is arranged radially closer to the longitudinal axis of the pump than the spring 102, together with the seal ring 106 seals the blocking agent space 80 toward the pump inlet housing 84.

From Fig. 5 shows an eccentric screw pump, which largely corresponds to the exemplary embodiment of FIG. 4. The essential difference of this embodiment Fig. 5 is that directly to the rotor 28, a second diameter reduction 108 connects. Both diameter reductions 90, 108 can have the same width b and the same diameter d. The distance A of the diameter reductions 90, 108 corresponds to 3.2 times the value of the diameter reduction or the cross section of the corresponding rotor head and rotor extension sections. Depending on which material was selected or required, the width b of the second Diameter reduction 108 may be greater than the width of the diameter reduction 90. Equally different may also be the diameter d of the diameter reductions 90, 108. To avoid unnecessary wear, the diameter reductions are introduced in the form of round notches. To improve the sealing function, the bellows 104 and the spring 106 are mounted between the diameter reductions on a part of the rotor head 26 whose diameter D corresponds to 0.5 to 2 times the rotor diameter.

If in the so-called pump lantern, in which the sliding joint 92 is arranged with its two linear units, another liquid operating means are used as the blocking means, then a double-sided mechanical seal will be used.

In Fig. 6, a seal 110 is shown, in which on both sides of the sealing disc 82 slide rings 34, 34 'abut the sliding surfaces 114, 114'. The sliding ring 34 'is under the pressure of the spring 102' on the right sealing surface of the sealing disc 82 at. The diameter jump between the rotor head 26 and the shoulder 96 with respect to the fixing and bearing adjustment of the sliding ring 34 'is compensated by the diameter-reinforced clamping piece 112. Both clamps are braced by screws to the rotor. The sliding joint has two linear units offset by 90 °, consisting of profile rails and associated carriages.

Claims

claims

1.

An eccentric screw pump having a stator (22) with a helical cavity and an eccentrically arranged therein helical rotor (28), wherein on one side of the stator, a connection part (18) and on the other side a pump housing (14) is arranged, which is a joint and a bearing (42) receives. characterized in that the rotor (28) has at its respective pressure side a pressure measuring device which is connected to a device (46) between the rotor and the joint, which counteracts the axial pressure occurring at the rotor.

Second

Eccentric screw pump according to claim 1, characterized in that a part of the device (46) acting on the rotor (28) is arranged between a seal (32) and a joint (44).

Third

Eccentric screw pump according to one of claims 1 to 2, characterized in that the device has a hydraulic and / or electrical connection to the pressure side of the rotor (28).

4. Eccentric screw pump according to one of claims 1 to 3, characterized in that the rotor (28) or a part connected to it has a switching element which is directly or indirectly connected to the pressure side of the rotor.

5th

Eccentric screw pump according to one of claims 1 to 4, characterized in that the rotor (28) has a in the pump housing (14) extending extension (2).

6th

Eccentric screw pump according to claim 5, characterized in that the extension (2) carries a sliding ring (34) which rests on a sliding surface of the support disc (36) on the bearing housing.

7th

Eccentric screw pump according to claim 6, characterized in that the sliding ring (34) has an elastic bellows (38).

8th.

Eccentric screw pump according to one of claims 6 or 7, characterized in that the sliding ring (34) performs a rotating and an eccentrically revolving movement.

9th

Eccentric screw pump according to one of claims 6 to 8, characterized in that the bearing housing consists of two support discs (36, 36 ') and an intermediate spacer tube (50).

10th

Device according to one of claims 6 to 9, characterized in that a radially movable middle disc (40) is arranged between the support discs (36, 36 ').

11th

Eccentric screw pump according to one of claims 6 to 10, characterized in that the central disc (40), the spacer tube (50) and the two support discs (36, 36 ') define a pressure medium space (48).

12th

Eccentric screw pump according to one of Claims 6 to 11, characterized in that sealing rings (66, 68) are provided on both end faces of the middle plate.

13th

Eccentric screw pump according to claim 12, characterized in that the sealing rings (66, 68) have different sizes.

14th

Eccentric screw pump according to one of claims 1 to 13, characterized in that the sealing rings (66, 68) are arranged at different distances from the longitudinal axis (76) of the rotor.

15th

Eccentric screw pump according to claim 14, characterized in that different sized pressure surfaces (70, 72) are provided between the sealing rings (66, 68) of the central disk and the support disks.

16th

Eccentric screw pump according to claim 15, characterized in that the difference of these pressure surfaces (70, 72) to the pressure surfaces of the rotor at its respective pressure side is equal to or greater.

17th

Eccentric screw pump according to claim 16, characterized in that a bearing (42) is arranged between the rotor extension and the central disc (40).

18th

Eccentric screw pump according to one of claims 6 to 17, characterized in that there is a spatial connection between the storage area and the joint area.

19. Eccentric screw pump according to claim 18, characterized in that a sliding joint (44) is arranged in the hinge region, which is directly connected to a drive shaft (54).

20th

Eccentric screw pump according to one of claims 1 to 19, characterized in that the drive shaft (54) is connected to the sliding joint (44) only via a feather key.

21st

Eccentric screw pump according to one of claims 8 to 20, characterized in that the extension of the sliding joint (44) is directly connected to the rotor head part (26)

22

Eccentric screw pump according to one of claims 17 to 21, characterized in that a sleeve (56) is attached to the sliding joint, which is in communication with the drive shaft (54).

23rd

Eccentric screw pump according to one of claims 1 to 22, characterized in that a rotor line (52) is arranged between the pump pressure side and the pressure medium chamber (48).

24. Eccentric screw pump according to one of claims 9 to 23, characterized in that at least in one of the support discs (36, 36 ') has a bore (74) is provided, which communicates with the rotor line (52).

25th

Eccentric screw pump according to one of claims 9 to 24, characterized in that the bore (74) of the support disc (36) and the pressure medium chamber (48) are connected via an opening.

26th

Eccentric screw pump according to one of claims 23 to 25, characterized in that there is a barrier liquid in the pressure medium chamber (48) and in the pipeline (52, 52 ').

27th

Eccentric screw pump according to one of claims 10 to 26, characterized in that .the rotor cross-section in the region of the support disc (36, 36 ') has a reduction.

28th

Eccentric screw pump according to one of claims 1 to 27, characterized in that the bearing (42) consists of a spherical roller bearing, which is connected to both the rotor head (26) and with the central disc (40).

29. Eccentric screw pump according to one of claims 1 to 28, characterized in that in the pump housing (14) the seal (31) of the bearing (42), the joint (44) and the means (46) for compensating the axial pressure are arranged.

30th

Eccentric screw pump according to one of claims 1 to 29, characterized in that on the inside of the pump housing several different-length spacer sleeves (50, 60) rest, which determine the length of the areas for the joint, the bearing and the seal.

31. Eccentric screw pump according to one of claims 1 to 30, characterized in that the support disks or spacers are axially secured in the pump housing by means of screws and washers.

32nd

Eccentric screw pump according to one of claims 1 to 31, characterized in that the pressure and / or suction side has electrical / electronic pressure sensors, which are connected via control means with electric hydraulic pressure booster.

33. Eccentric screw pump according to claim 32, characterized in that a fluid pressure accumulator is used as a pressure booster.

34th

Eccentric screw pump according to one of the preceding claims, characterized in that the rotor (28) or the rotor head or a shaft arranged between the rotor and the joint or the drive shaft comprises a position measuring device in the form of a strain gauge or other electronic / electrical measuring devices.

35th

Eccentric screw pump according to one of the preceding claims 9 to 35, characterized in that the end faces 70, 72 of the central disc 40 and / or the complementary surfaces of the support discs 36, 36 'made of wear-resistant material.

36th

Method for operating an eccentric screw pump, characterized in that the reaction pressure occurring at the respective pressure side of the pump is measured and a consequent equal or slightly higher back pressure is exerted on the rotor on a region between the rotor and the joint.

37th

A method according to claim 36, characterized in that the rotor or the rotor head or the propeller shaft or the drive shaft have a measuring device which has a position device, can be detected by the counter-pressure acting on the rotor and counteracted this.

38th

Method according to one of claims 36 or 37, characterized in that a counter-pressure acting on the rotor is detected by visual, capacitive or inductive measuring methods and counteracted thereby.

39th

Process according to claims 36 to 38, characterized in that a reaction pressure control is carried out on the basis of the reaction pressure resulting at the pressure side of the pump.

40th

An eccentric screw pump having a stator (22) with a helical cavity and an eccentrically arranged therein helical rotor (28) whose rotor head (26) is connected to a hinge, wherein between the rotor (28) and the joint a seal sits, the eccentric Rotor movement follows characterized in that the seal consists of at least one sliding ring (106) and a sealing disc (82) and a rotor head (26) or a rotor extension in the region between the rotor (28) and the sealing disc (82) at least one diameter reduction (90 , 108).

41st

Eccentric screw pump according to claim 40, characterized in that the diameter of the rotor head (26) or the rotor extension in the region of the diameter reduction (90, 108) is between 30% and 80% of the rotor (28).

42nd

Eccentric screw pump according to claim 41, characterized in that the diameter reduction (90, 108) is between 30% and 60% of the diameter of the rotor.

43rd

Eccentric screw pump according to claim 41 or 42, characterized in that the diameter reduction is 50% of the diameter of the rotor.

44th

Eccentric screw pump according to one of claims 40 to 43, characterized in that the diameter reduction (s) of the rotor extension (26) have the same or different values.

45th

Eccentric screw pump according to one of claims 40 to 44, characterized in that the distance of the diameter reductions (90, 108) corresponds to two to ten times the value of the respective diameter reductions.

46th

Eccentric screw pump according to claim 45, characterized in that the distance corresponds to two to six times the respective diameter reductions.

47th

Eccentric screw pump according to claim 45, characterized in that the distance corresponds to two to four times the respective diameter reductions (90, 108).

48th

Eccentric screw pump according to one of claims 40 to 47, characterized in that the diameter of the rotor extension between at least two diameter reductions corresponds to 1.2 to 3 times the rotor diameter.

49th

Eccentric screw pump according to claim 48, characterized in that the diameter (D) of the rotor head (26) or the rotor extension corresponds to 1.2 to 2 times the rotor diameter.

50. Eccentric screw pump according to one of claims 40 to 49, characterized in that at the same values of the diameter reductions (90, 108), the width b of the constriction on the rotor by at least 20% greater than the width of the constriction in the region of the sealing disc (82). ,

51st

Eccentric screw pump having a stator (22) with a helical cavity and an eccentrically arranged therein helical rotor (28) whose rotor head (26) is connected to a joint, wherein between the rotor (28) and the joint a seal (32) sits, which follows the eccentric rotor movement and the seal consists of at least one sliding ring (34) and a sealing disc, characterized in that a sliding ring (34) is arranged on both sides of the sealing disc (82) and the sealing disc (82) has at least one radial bore (78). has, which ends in the blocking agent space (80).

52nd

Eccentric screw pump according to claim 51, characterized in that that the diameter of the rotor extension in the two areas beyond the sealing disc (82) has different sizes.

53rd

Eccentric screw pump according to claims 51 or 52, characterized in that the largest diameter of the rotor extension of the two areas corresponds to 1.2 to 3 times the smallest diameter.

54th

Eccentric screw pump according to claim 52 or 53, characterized in that a sealing disc (82) with two sliding surfaces (114, 114 ') is provided.

55th

Eccentric screw pump according to claim 52, characterized in that the sliding rings (34 ', 34 ") are connected to springs, which are supported on clamping pieces (100, 100').

56th

Eccentric screw pump according to claim 55, characterized in that between the springs (102, 102 ') and the pump axis bellows (104, 104') are arranged.

57th

Eccentric screw pump according to claim 56, characterized in that one side of the bellows (104, 104 ') are each connected to a clamping piece (100, 100') attached to the rotor head extension.

58. Eccentric screw pump according to one of claims 40 to 57, characterized in that the sealing disc (82) between the pump inlet housing (84) and the pump lantern (86), in which a sliding joint (92) is arranged.

59th

Eccentric screw pump according to claim 56, characterized in that at the end of Rotorverlängerang a sliding joint is fixedly mounted.

60th

Eccentric screw pump according to claim 59, characterized in that the sliding joint is connected to the drive shaft.

61. Eccentric screw pump according to claims 59 and 60, characterized in that the sliding joint consists of two linear units, which are arranged at 90 ° to each other.

62nd

Eccentric screw pump according to claim 61, characterized in that the linear units each consist of a rail and a carriage.