EP1601875B1 - Eccentric screw pump - Google Patents

Abstract

The invention relates to an eccentric screw pump (1) comprising a stator (2) and a rotor (3) between which the material, which is to be transported, is displaced when the rotor (3) is rotated in the stator (2) from an inlet area (4) on the suction side to a discharge area (5) on the pressure side. Said pump comprises a rotor head part (7) which closes the pressure-side discharge area (5) and which is fixed to the front (6) of the rotor (3), rotating therewith. Said rotor head part comprises at least one recess (8) which transverses the head part and which is disposed in the rotor head part (7) in relation to the rotor surface (6) which is to be maintained, such that the recess (8), which rotates at the same time as the rotor (3) in the direction of conveyance (10), opens up the pressure volume area (11, 11') and a recess-free rotor head part area (13) keeps the opposite-lying suction volume area (12, 12') sealed while the pressure volume area (12, 12') is opened.

Description

The invention relates to an eccentric screw pump for conveying abrasive material, which has a stator and a rotor, between which the conveyed is moved during rotation of the rotor in the stator of a suction-side input area to a discharge-side discharge, wherein in the discharge-side discharge a pressure-volume range and a suction volume range between the stator and the rotor as a result of the rotor rotation changes and alternately opposes, and a rotor head part which rotates with the rotor and which is attached to the end face of the rotor is provided on the discharge side discharge area.

Such known progressive cavity pumps include a screw-shaped rotor having the form of a high pitch and large thread depth round thread screw, and a stator having a thread-like internal structure and thus having the shape of a screw shell. In this case, the stator is formed by its thread-like internal structure of the suction side of the pressure side directed axially successively formed cavities in which the rotor rotates. Parts of the inner surface of the stator and parts of the outer surface of the rotor contact each other during rotation of the rotor, wherein between the Statorinnenfläche and the rotor outer surface conveying chambers and associated sealing areas are provided, wherein the conveyed in the delivery chambers when rotating the rotor in the cavities of the stator of the Suction side is moved to the pressure side along a conveyor line.

Such an eccentric screw pump for conveying media with high viscosity or high solids content is known from the publication EP 0 713 974, in which by the rotation of the rotor in the cavities of the stator, a continuous delivery of abrasive material - from solids and liquids - is possible. The eccentric screw pump is connected to a feed hopper, from which the abrasive conveyed material is conveyed to the inlet suction chamber of the eccentric screw pump. Opposite the Eingangsaugraum located at the other end of a discharge cavity, from which the abrasive conveyor is pressed out. The stator is made of elastic material and is applied with a bias on the rotor, which always creates a seal at the current end of the chamber. The conveyed material pressed out of the discharge-side discharge cavity presses, as a result of the conveyed material present in a continuing pressure pipe, as an opposing external pressure on the product rearward conveyed goods. The delivery process thus builds up an internal pressure, in particular against the sealing areas between stator and rotor.
The higher the external pressure build-up in the pressure tube, the greater must be the bias between the rotor and the stator to ensure a secure seal.

One problem is that the rotor and the stator are subject to wear, in particular during the conveyance of the conveyed material. Essentially, the wear on the pitches of the stator designed as seals of the cavities occurs starting from the side of the discharge-side discharge area in the direction of the suction-side entry area. The increase in wear causes the decrease in the delivery rate of the eccentric screw pump.

The elastic stator is applied with a bias to the rotor, whereby it can come through the conveyed to high wear between the stator and the rotor, which increases equivalently with increasing pressure. The wear progressively migrates from the pressure to the suction side and lifts the original sealing areas. If the internal pressure can no longer overcome the external pressure, the delivery process is finally terminated.

The pressure-oriented transport of the conveyed material in the delivery chambers is therefore highly dependent on the control of the seal in the sealing areas between the rotor and stator. In order to master the problems of disturbing wear in the sealing areas between the rotor outer surface and the stator inner surface over a longer operating time, are progressive cavity pumps with restressable stators in which stator-integrated clamping bars are provided or on which lockable clamping devices can be used manually. With the clamping devices can be made in recognizable wear on the inner sealing areas in detail or as needed as a whole radial compression of the stator and thus an approximation of Statorinnenfläche to the rotor outer surface, the approximation should lead to a production of the original seal in the sealing areas ,

There are further described in the document DE 33 04 751 C2 eccentric screw pumps with non-restressable stators for the promotion of abrasive materials, such as mixed cement and lime mortar and the like, in which either the stator conically narrows from the suction side to the pressure side at radially identically dimensioned rotor or the rotor is directed from the suction side to the pressure side has an increasing winding cross-section with uniformly sized stator.

One problem is that the production and the quality control in both options and also in a combination of both ways of sealing constant maintenance are associated with an increased material, monitoring and thus personnel expenses.

Furthermore, a compressor for cooling circuits for conveying cooling gas is described in document US Pat. No. 4,802,827, which comprises a closed housing with a separate suction chamber and a separate discharge chamber. In between there is a rotating part with a helical bore which expands along the axis of rotation of the rotating part. The Bore has a first and a second end opening, which communicates with the suction chamber or the discharge space via supply pipes. A firmly held, non-rotating, spiral inner member is inserted in the bore. The surrounding rotary member is driven by an electric motor part in the housing and moves around the inner part. In contact with the inner surface of the bore, the inner part defines a plurality of closed spaces that are moved from the first end opening to the second end opening. A cooling gas from the suction chamber is transported from the first end opening to the second end opening within the closed spaces and then discharged in the discharge chamber discharged in compression. The discharge of the compressed refrigerant gas is controlled by a valve mechanism. The valve mechanism is that either a head part is attached to either the end faces of the inner inner part or the outer rotating rotary part, which is provided either with closable discharge holes or edge-round holes, the head part side are partially outside the bore, and directed from the bore Notches are introduced into the rotary part, which correspond to the edge-side round holes of the head part during the gas discharge.

One problem is that the compressor is not suitable for conveying abrasive material containing solids. Even in the separate suction chamber as well as later in the separate discharge chamber blockages and hardening can take place, which immediately lead to the termination of the function of the compressor.
Likewise, the edge-side notches in the rotary part are not sufficient to change this state in the promotion of abrasive conveyed. The notches settle immediately with the existing solids of the abrasive material and block the promotion of the conveyed through the round peripheral discharge holes of the headboard.
A problem is also that the compressor is only suitable for the compression of cooling gas.

It is also an eccentric screw pump from the publication DE 202 15 819.7 known in which the discharge-side discharge an abrasive material passing let recirculation valve means is present, to which a rigidly attached to the end face of the stator Verschlulssscheibe heard. The rotor rotates with its end face on the closure disk, whereby a seal of the alternating pressure and suction volume ranges is to be achieved. The stator-mounted closure disk has two stationary passage openings for the discharge of the abrasive material to be conveyed, to each of which a check valve is assigned. The two valve-fitting passage openings are assigned to the discharge volume of the rotor occupied pressure-volume range and suction volume range and are opened when the internal pressure in the respective volume ranges between the stator and the rotor is greater than the voltage applied to the valve outer pressure in the conveyed further pressure tube.

One problem is that the formation of the stator-mounted closure disk with the valves requires additional components. The valves must at least be cleaned after applications of the eccentric screw pump, because after their use, in general, the abrasive material cures and the valves become blocked.

The invention has for its object to specify a Exzenterschnekkenpumpe, which in the region of the discharge in montageeinfacher and maintenance-improved manner is formed. At the same time, the wear in the sealing regions of the stator and rotor, in particular in the pressure region of the discharge-side discharge cavity, should be substantially slowed down or substantially reduced. In this case, the already short lengths of the stator and the rotor or the conveyor line should be further shortened and the original capacity over a longer period of time largely maintained.

The object is solved by the features of claim 1. In the eccentric screw pump for conveying abrasive material according to the preamble of claim 1, the rotor head part from the edge of a supporting rotor end face outgoing, radially sector-shaped passage opening or sector-like recess as Kopfteiildurchgängige recess on the effective opening cross-section with the pressure generation within the pressure Volumetric range enters the pressure-volume range and after passing the pressure-volume range again emerges from the pressure-volum area, wherein the rotatable with the rotor in the conveying direction recess opens the pressure-volume range concomitantly and wherein the recess-free rotor head portion during the opening period of the pressure Volume area keeps the opposite suction volume area sealingly closed.

The attachment of the rotor head part is on the rotor end face by screwing, welding or the like. brought about with the rotor head part rear surface.

The rotor head part can be attached to the rotor end face such that the central axis of the rotor head part with can match the center of the rotor end face. Then, the movement of the center axis represents a centric rectilinear elongation, in no match can be passed through an eccentric curve path.

The continuous recess is introduced immediately laterally on the end face of the rotor in the rotor head part, wherein the recess cross-section is predetermined dimensioning with the pressure build-up within the pressure-volume range and the discharge of the conveyed by the rotating rotor.

The rotor head part may preferably be a rotor disk with circular surfaces. The associated continuous recess can be a largely bean-shaped oblong cross-section in the cross-section, which represents a sector-section-shaped passage opening.
The rotor head part is in this case attached to the rotor end face in such a way that the slot enters the pressure volume range from the edge of the supporting rotor end face in the radial direction with its effective opening cross-section with the pressure generation within the pressure volume range with the oblong-catch area and later with the slot end area the pressure-volume range exits again.

To reduce the pressure on the sealing regions within the stator, the rotor head part has such circumferential dimensions that the rotor head part with its remaining recess-free rotor head part region keeps the respective suction volume region formed during the rotation closed in the region of the stator opening.

The Rotorkopfteilfrontfläche facing away from the rotor end face may optionally be provided with a flat surface with respect to the disk-shaped formation, spherical cap-shaped and / or with at least one wing or other projections having profile for improving the mixing of the conveyed material.

The rotor may be formed as a screw in the form of a round thread screw with high pitch and large thread depth, wherein the stator is a screw shell and axially successively formed cavities - at least one suction-side inlet cavity and a discharge-side discharge cavity - a conveyor line, wherein between the Statorinnenfläche and the Rotor outer surface forming delivery chambers by adapted between the stator and the rotor sealing regions, wherein the conveyed material is displaceable in the delivery chambers during rotation of the rotor in the cavities of the stator from the suction-side entrance to the discharge-side discharge.

At the Statorstirnfläche a pressure tube is connected, via which the conveyed material is passed, wherein the pressure tube is sealed by means of at least one stator and pressure tube comprehensive support member sealed on the stator.

The conveyor line can be based on two cavity lengths or on an "entry cavity cavity discharge cavity" arrangement.

The conveyor line can also be shortened to a helical gear of the stator, wherein the rotor head part contributes in particular to the position stabilization of the rotor.

The invention makes it possible for the presence of the rotor head part at the discharge-side discharge region to achieve a separation of the original pressure pipe-related pressure chamber from the pump outlet from the original pump-related discharge-side discharge cavity. After the opening of the discharge-side discharge region through the respective rotor rotation-related opening by means of the continuous recess, a subsequent gentle Fördergutfüllung is obtained from the suction-side input area directed by the rotating rotor.

The invention will be explained in more detail by means of an embodiment with reference to drawings.

Fig. 1

eine schematische perspektivische Explosionsdarstellung einer erfindungsgemäßen Exzenterschneckenpumpe mit einem von der Rotorstirnfläche gelösten Rotorkopfteil und einem von der Statorstirnfläche gelösten anschließbaren Druckrohr,

Fig. 2

eine schematische stirnseitige Draufsicht auf ein Rotorkopfteil mit einem Langloch in einer Position zu Beginn des Austrags von Fördergut aus einem Druck-Volumenbereich bei einem festgelegten Rotor-Winkel α gleich 0°,

Fig. 3

eine schematische stirnseitige Draufsicht auf das Rotorkopfteil mit dem Langloch in einer Position bei maximalem Austrag von Fördergut aus dem Druck-Volumenbereich bei einer Drehung des Rotors um einen Rotor-Winkel α gleich 90° nach Fig. 2,

Fig. 4

eine schematische stirnseitige Draufsicht auf das Rotorkopfteil mit dem Langloch in einer Position nach Ende des Austrags von Fördergut aus dem bisherigen Druck-Volumenbereich bzw. zu Beginn der Austrags von Fördergut aus dem sich neu aufbauenden, gegenüberliegenden Druck-Volumenbereich bei einer Drehung des Rotors um einen Rotor-Winkel α gleich 180° nach Fig. 2,

Fig. 5

einen Längsschnitt durch eine verkürzte Exzenterschneckenpumpe mit dem Rotorkopfteil nach Fig. 3 längs der Linie I-I,

Fig. 6

eine schematische Darstellung des Rotorkopfteils mit einer vergrößerten sektorabschnittsförmigen Durchgangsöffnung nach Fig. 4 und

Fig. 7

eine schematische Darstellung des Rotorkopfteils mit einer sektorartigen Aussparung nach Fig. 4.

Show it:

Fig. 1

3 is a schematic perspective exploded view of an eccentric screw pump according to the invention with a rotor head part detached from the rotor end face and a connectable pressure pipe detached from the stator end face,

Fig. 2

a schematic frontal plan view of a rotor head part with a slot in a position at the beginning of the discharge of conveyed material from a pressure-volume range at a fixed rotor angle α equal to 0 °,

Fig. 3

a schematic frontal plan view of the rotor head part with the slot in a position with maximum discharge of material to be conveyed from the pressure-volume range upon rotation of the rotor by a rotor angle α equal to 90 ° according to FIG. 2,

Fig. 4

a schematic frontal plan view of the rotor head portion with the slot in a position after the end of the discharge of conveyed from the previous pressure-volume range or at the beginning of the discharge of conveyed from the newly building, opposite pressure-volume range in a rotation of the rotor to a Rotor angle α equal to 180 ° according to FIG. 2,

Fig. 5

3 shows a longitudinal section through a shortened eccentric screw pump with the rotor head part according to FIG. 3 along the line II;

Fig. 6

a schematic representation of the rotor head portion with an enlarged sector-section-shaped passage opening according to Fig. 4 and

Fig. 7

a schematic representation of the rotor head portion with a sector-like recess of FIG .. 4

Hereinafter, FIGS. 1 and 6, 7 will be considered together. 1 shows, in a schematic exploded view, an eccentric screw pump 1 for conveying abrasive material, which has a stator 2 and a rotor 3, between which the material to be conveyed when rotating the rotor 3 in the stator 2 from a suction-side input area 4 to a discharge-side discharge area 5 is shifted, wherein in the discharge region 5 a pressure-volume region 11 and a suction volume region 12 between the stator 2 and the rotor 3 rotordrehbedbedingt Change in volume and alternately opposite and a the discharge-side discharge 5 final ßendes, attached to the end face 6 of the rotor 3, with the rotor 3 rotating rotor head part 7,7 'is provided.

According to the invention, the rotor head part 7,7 ', as shown in Figure 6.7, from the edge 38 of the supporting rotor end face 6 outgoing, radially directed sector section-shaped passage opening 32 or sector-like recess 31 as a recess 8, with its effective opening cross section with rotorkonform the pressure generation within the pressure-volume range 11 enters the pressure-volume range 11 and, after sweeping the pressure-volume range 11, emerges again from the pressure volume range 11, whereby the recess 8, 31, 32 which rotates in conformity with the rotor 3 in the conveying direction 10 the pressure-volume region 11 concomitantly opens and wherein the recess-free rotor head portion 13 during the opening period of the pressure-volume region 11 keeps the opposite suction volume region 12 sealingly closed.

The rotor head part 7 is preferably formed as a rotor disk, on its rear surface 30 planar and with its rotor head part rear surface 30 by screwing, welding or the like. attached to the rotor end face 6 of the helical rotor 3, actually the rotor screw end face. The rotor head part 7 is thus an integral part of the rotor 3 outside the stator 2.

The rotor head part 7 may be secured to the rotor end face 6 with its disk rear face 30 in such a way that the center axis 33 of the rotor head part 7 is provided with a circular disk front face 9 and circular disk rear face 30 may preferably coincide with the center 28 of the rotor face 6, wherein the central axis 33 elongated only rectilinear. However, if the center axis 33 of the rotor head part 7 is displaced away from the center point 28 of the rotor end face 6, then no centrically rectilinear elongation but an eccentric curved path will pass through.
The front surface 9 and the rear surface 30 may be circumferentially but also oval-shaped, pear-shaped in cross-section or egg-shaped od. Like. Be designed in particular for material reduction. In FIG. 2, for example, a material-reduced second rotor head part 37 (dashed line) is inserted.

It is essential that the recess 8 is formed such that during the rotation of the rotor, the suction volume area 12, 12 'always remains sealed and the pressure volume area 11, 11' is opened in a manner conforming to the rotor.

As a continuous recess 8, the rotor head part 7 in FIG. 1 preferably has a largely bean-shaped oblong hole in the top-view cross-section, which represents a special sector-section-shaped passage opening.

As is also shown in FIGS. 2 to 4, the oblong hole 8 is introduced directly laterally from the edge and in the radial direction expands on the end face 6 of the rotor 3 in the rotor head part 7, the top-view oblong slot cross-section dimensioning-compliant with the pressure build-up in the pressure Volumetric range 11 and the discharge of the conveyed material from the pressure-volume region 11 out through the rotating rotor 3 is predetermined.

The rotor 3 is in the form of a round thread screw (cord thread) with high pitch and large thread depth and acts as Fördergutverdränger and as a sealant along the conveying path 14 from the suction-side input area 4 to the discharge-side discharge area 5 between the rotor 3 and the stator 2. The stator 2 includes axially successive and due to the pitch and the depth of the thread formed cavities 15,16,17 - a suction-side inlet cavity 15, a central delivery cavity 16, a discharge-side discharge 17 -, wherein between the Statorinnenfläche 18 and the rotor outer surface 19, the delivery chambers 20, 21,22 formed by between the stator 2 and the rotor 3 sealing regions 23,24, wherein the conveyed in the delivery chambers 20,21,22 when rotating the rotor 3 in the cavities 15,16,17 of the stator 2 of the suction-side entrance area 4 is transported to the discharge-side discharge area 5.

In this case, the rotor 3 shifts by its helical formation of the conveyed material in the axial direction 10 along the conveying path 14 and at the same time in the radial direction with respect to the pump central axis 26 alternately in the discharge cavity 17 via the nachschiebenden delivery chambers 20,21,22 in provided, training and opposite volume regions 11, 12 which are part of the discharge-side discharge cavity 17.

In the discharge area 5 of the discharge-side discharge cavity 17, which corresponds approximately to a "half" central cavity 16, similar to the first, shown in Fig. 1 delivery chamber 20, there is the conveyed through the recess 8 letting rotor head part 7, the in Fig. 1 For better explanation, because of the rotor end face 6 in an exploded view detached and according to the invention when sealing against the rotor end face 6 sealingly abuts against the stator end face 25.

The rotor head part rear surface 30 and the stator end face 25 have a planar surface and each have an angle of approximately 90 ° to the pump center axis 26.

The rotor head part front surface 9 may be provided with a planar surface with respect to a disc-shaped design, but also spherical cap-shaped and / or with at least one wing or other projections having profile for improving the mixing of the conveyed material.

The pressure-side discharge region 5 of the eccentric screw pump 1 comprises the last section of the eccentric screw pump 1 which delivers the conveyed goods, while the suction-side input region 4 represents the first section of the eccentric screw pump 1 receiving the conveyed material.

The invention thus makes it possible that the conveyed material ejected from the eccentric screw pump 1 no longer flows back after the rotor rotation-related opening of the pressure-volume region 5 and the sealing of the suction volume region 12 through the slot-free disk part 13 and does not flow back onto or from the rotor 3. nachgesaugte conveyed can press.

The bean-shaped slot 8 allows the material to flow through it without substantial resistance, while a return flow of the material to be conveyed in the direction of the suction volume region 12 is blocked by the slot-free disk part 13 therethrough.

Thus, at least one discharge of the sealing area 23 in the areas of the stator 2 and the rotor 3 takes place with each rotation of the rotor 3, whereby a reduction in wear occurs.

On the Statorstirnfläche 25, as shown in Fig. 1, one of the rotor head part front surface 9 zugewendetes pressure tube 34 can be fastened, via which the conveyed material is forwarded.
The pressure tube 34 can be sealed by means of at least one preferably stator and pressure tube comprehensive support member (not shown) on the stator 2.

In Fig. 2, the rotor 3 is located in the suction volume region 12 with its circular rotor end face 6 at an angular and rotational position 28, in which the rotor angle α, for example, is set equal to 0 °. The rotor head part 7 as a rotor disk is attached to the rotor end face 6 in such a way that the bean-shaped slot 8 starts with its oblong slot catch area 35 to a very small part of its effective opening cross section to cover the pressure volume area 11. Compliant with the pressure generation by the rotating rotor 3 in the pressure-volume range 11, the cross-sectional slot size of the opening coverage of the pressure-volume area 11 is also larger. Depending on the size of the bean-shaped oblong hole 8, the remaining and long-hole-free disc part 13 can close off a part of the remaining pressure-volume area 11 and close off the suction volume area 12 in a sealing manner. The position of the rotor disk 7 to the rotor 3 in Fig. 2 corresponds approximately to the position of the rotor disk 7 to the stator 2 in Fig. 1st

In Fig. 3, the rotor 3 has rotated through an angle α of 90 ° in the mid-position 28 ', whereby the bean-shaped slot 8 langlochquerschnittsmäßig completely including the slow-motion trapping region 35 and the Langlochendebereiches 36 covers the largest part of the pressure-volume range 11 and this has thus opened and wherein the slot-free disk part 13 still seals the suction volume region 12 sealed.

In Fig. 4, the discharge of the conveyed material from the pressure-volume region 11 by rotating the rotor 3 by a rotor angle α of another 90 °, i. a total of 180 °, in the mid-position 28 "terminates, whereby the slot 8 comes out with its Langlochendebereich 36 from the degraded pressure-volume region 11. The original suction volume range 12 is still closed sealed by the slot-free disk part 13, is but as a result of the rotor rotation as a pressure-volume region 11 'as in Figure 2 rotordrehungskonform starting open.The slot 8 occurs with its Langlochanfangsbereich 35 in the building up opposing pressure-volume range 11' a.

4 also shows that the oblong hole 8 can be formed as a continuous recess in another embodiment in the form of a radially directed sector-section-shaped passage opening 32 or sector-like recess 31 extending from the supporting rotor end face 6, which are respectively dashed.

The rotor disk 7 shown in FIGS. 2, 3, in an end-side plan view, for pressure reduction, at least on the sealing area 24 within the eccentric screw pump 1 has such circumferential dimensions that the stator opening 27 always keeps sealed the respective resulting suction volume region 12 when the rotor disk 7 rotates. Thus, the rotor head part 7 may deviate from the circular disk and a triangular-shaped rounded shape, as shown in Fig. 2, as a second Rotorkpfteil 37 have (dashed lines).

In Fig. 5, the eccentric screw 1 is shown as an abbreviated longitudinal section along the line I-I of FIG. 3 schematically. The rotor disk 7 is dimensioned such that it remains within its range of motion in the rotor rotation preferably within the stator jacket 29, i. does not move beyond the stator jacket 29. The rotor disk 7 is fixedly connected to the rotor end face 6 on its disk rear surface 30. The disc rear surface 30 is formed in the slot-free region 13 so planar that it is tight against the also preferably planar stator end face 25 and forms an angle of approximately 90 ° to the pump center axis 26. The slot 8 opens the pressure-volume region 11 the passage of the material to be conveyed to the subsequent pressure tube 34. The slot-free disk part 13 keeps the suction volume part 12 of the discharge-side discharge cavity 17 closed.

5, due to the invention, only one position-related sealing region 24 of a screw thread can be formed in a minimally short formation of the stator 2, wherein a suction-side discharge region 5 can connect directly to the suction-side input region 4. The position stabilization of the rotor 3 in the flight is given by the voltage applied to the stator end face 25 rotor head part 7.
In FIGS. 6, 7, two different rotor head parts 7, 7 'are shown analogously to the sector-section-shaped passage opening 32 and sector-shaped recess 31, each drawn in broken lines in FIG. 4, as recesses 8 in a fastening possible on the rotor surface 6. The rotor head part 7 according to FIG. 6 has the radially directed passage opening 32 emanating from the edge 38 of the rotor end face 6, while the rotor head part 7 'according to FIG. 7 contains the radially directed sector-like recess 31 starting from the edge 38 of the rotor end face 6.

• Der metallische Rotor 3 (Schnecke) rotiert in dem aus elastischem Material bestehenden Stator 2 (Schneckenmantel) und dichtet die Förderkammern 20,21,22 an der Statorinnenfläche 18 ab. Durch die Drehung des Rotors 3 wird das Fördergut in den Förderkammern 20,21,22 von dem saugseitigen Eingangsbereich 4 zum druckseitigen Austragsbereich 5 verschoben. Es ergibt sich dabei im Stator 2 ein kontinuierlicher Fördergutstrom, der das Langloch 8 des Rotorkopfteils 7 pulsierend verlässt.
• Wird der Fördergutstrom in den druckseitigen Austragshohlraum 17 verschoben, insbesondere über die Förderkammer 22, wird das Fördergut innerhalb des sich verkleinernden Volumenbereiches 11 durch das jeweils durch die Rotorrotation im Druck-Volumenbereich 11 positionierte Langloch 8 hindurch gepresst, während der Saug-Volumenbereich 12 verschlossen bleibt.

The operation of the eccentric screw pump 1 according to the invention takes place as follows:

• The metallic rotor 3 (screw) rotates in the stator made of elastic material 2 (screw shell) and seals the delivery chambers 20,21,22 on the stator inner surface 18 from. As a result of the rotation of the rotor 3, the conveyed material in the delivery chambers 20, 21, 22 is displaced from the suction-side entry region 4 to the delivery-side discharge region 5. This results in the stator 2, a continuous Fördergutstrom that leaves the slot 8 of the rotor head part 7 pulsating.
• If the conveyed product flow is displaced into the discharge-side discharge cavity 17, in particular via the delivery chamber 22, the conveyed material is pressed inside the decreasing volume region 11 through the slot 8 positioned in each case by the rotor rotation in the pressure-volume region 11, while the suction volume region 12 remains closed ,

At the end of the discharge process, which takes place by means of a further rotor rotation, the rotor end face 6 reaches a position 28 ", in which the decreasing pressure-volume region 11 changes into a pressure-volume region 11 'which has been completely sucked with material to be conveyed and which has hitherto been the suction volume region 12. By the rotor rotation beyond a rotor angle a of 180 ° the pressure in the resulting pressure-volume region 11 ', which presses out the conveyed material from the elongated hole 8 in a rotationally conforming manner, passes through the existing pressure-volume region 11 into the newly formed suction-volume region 12' due to the rotation of the rotor 12. Thereafter, the previously opened pressure-volume region 11 is passed through Thus, no back pressure can build up on the conveyed material located in the subsequent delivery chamber 21, and also the sealing regions 24, 23, in particular the last sealing region 24 of the delivery-side discharge cavity 17, are not back-pressure-loaded. On the contrary, by the enlarging sow g-volume region 12 'exerted a strong suction effect on the subsequent conveyed from the delivery chamber 21.

Due to the respective change of the rotor 3 in the two extreme position positions 28,28 "of the radially opposite volume regions 11,12 and 12 ', 11' within the pressure-side discharge cavity 17 is formed by the rotor disk 7 according to the invention, a change of pumping operations and suction of the Material to be conveyed within the discharge cavity 17, wherein by the simultaneous suction and conveyance of the conveyed material in the respective disk-closed volume regions 12 or 12 'in there a higher degree of filling of material to be conveyed is achieved.

The invention allows the conveyor line 14 to be shortened and referenced to two "cavity lengths" or to an "entry cavity cavity discharge cavity" arrangement 15-16-17. Optionally, the conveyor section 14 may be shortened to a helix of the stator 2.
By attaching the rotor head part according to the invention, in particular the rotor disk 7 on the previous Rotorendteil of progressing cavity pumps and associated with the advantages of possible shortening of already produced progressing cavity pumps with relatively long stators and rotors, the required drive power can be achieved by means of a power-reduced motor, and thus also Energy and material can be saved.

An increase of the delivery pressure is achieved in principle by an increase in the bias voltage between the stator 2 and the rotor 3, which usually takes place axially in a conventional manner, for example by means of a clamping jacket comprising the stator 2.
One problem is that this is associated with a correspondingly increased energy expenditure for pump operation.

In order to operate the eccentric screw pump 1 according to the invention energetically efficiently even under elevated conveyor backs, a corresponding increase in the preload in the radial direction to the pump center axis 26 is provided with the lowest possible axial formation.

In this case, in the regions of the stator 2 in preferably integer intervals of a screw shell thread turn corresponding to one revolution of the rotor end face 6 optionally be provided a radial cross-sectional taper.

In the case of a stator 2 having more than one worm-gear thread, a radial cross-sectional tapering element (not shown) may be associated with the stator 2 in a distance corresponding to a worm-gear thread of the stator 2 from the rotor end face 6.

The radial cross-sectional tapering element can be designed and arranged as an element system inside and / or outside of the stator jacket 29, which can be controlled selectively or controlled via actuators in the radial direction and with the radial bias of the sealing regions 23,24 of the stator 2 relative to the rotor 3rd either stepwise or continuously adjustable in dependence on the predetermined delivery pressure.

The invention opens up the possibility that in addition to the time delay of the wear education and the manufacturing costs compared to the complicated configurations of known nachspannbaren and non-retensioning eccentric screw pumps and known check valve devices can be reduced at Statorendbereich of progressing cavity pumps.

LIST OF REFERENCE NUMBERS

1

Cavity Pump

2

stator

3

rotor

4

suction-side entrance area

5

discharge side discharge area

6

Rotor face

7,7 '

first rotor head part

8th

continuous recess

9

Rotor head front face

10

Rotationally conveying direction

11

first pressure-volume range

11 '

second pressure-volume range

12

first suction volume range

12 '

second suction volume range

13

long hole-free rotor head portion

14

conveyor line

15

suction-side entry cavity

16

medium production cavity

17

discharge side discharge cavity

18

stator surface

19

Rotor outer surface

20

first delivery chamber

21

second delivery chamber

22

third delivery chamber

23

first sealing area

24

second sealing area

25

stator face

26

Pump central axis

27

stator opening

28

Rotor end face center at α = 0 °,

28 '

Rotor end face center at α = 90 °,

28 "

Rotor end surface center at α = 180 °,

29

stator

30

Rotor head rear surface

31

sector-like recess

32

sector-section-shaped passage opening

33

Rotor head central axis

34

pressure pipe

35

Slot starting area

36

Slot end area

37

second rotor head part

38

edge

Claims (9)

1. Eccentric screw pump (1) for conveying abrasive materials, featuring a stator (2) and a rotor (3), between which the material to be conveyed is displaced by means of a rotating rotor (3) inside the stator (2), from a suction-side inlet section (4) to a pressure-side discharge section (5), in which a pressure chamber (11) and a suction chamber (12) inside the pressure-side discharge section (5) keep changing and alternating opposite one another, between the stator (2) and the rotor (3), due to the rotating rotor and a rotating rotor head, fixed on the face surface (6) of the rotor (3) and rotating with the rotor (3), is provided to close the pressure-side discharge section (5),
   characterized in that,
   the rotor head (7, 7', 37) features either a radially oriented sector-section-shaped passage opening (32) starting from the edge (38) of the holding rotor face surface (6) or a sector-type cut-out (31) as a rotor-head opening recess (8), which, with its effective opening cross-section, enters rotor-conform into the pressure chamber (11, 11') during pressure development within the pressure chamber (11, 11') and after sweeping over the pressure chamber (11, 11'), exits the pressure chamber (11, 11'), whereby the recess (8, 31, 32) that rotates conform with the rotor (3) in the conveyor direction (10) gradually opens the pressure chamber (11, 11') and during the opening period of the pressure chamber (11, 11') the rotor head without recess (13) thereby keeps the opposite suction chamber (12, 12') sealed and closed.
2. Eccentric screw pump according to Claim 1,
   characterized in that,
   the rotor head (7, 7', 37) features circumferential dimension such that the rotor head (7, 7', 37) opens the pressure chamber (11, 11') during rotation and keeps the suction chamber (12, 12') in the area around the stator opening (27) closed.
3. Eccentric screw pump according to Claim 1 and/or 2,
   characterized in that,
   the rotor head (7, 7', 37) fastening on the rotor face surface (6) is brought about with the rotor-head rear surface (30), wherein the rest of the rotor-head rear surface (30) and the stator face surface (25) are evenly surfaced and form an angle of approx. 90° with the pump centre axis (26).
4. Eccentric screw pump according to at least one of the preceding claims,
   characterized in that,
   the recess (8, 31, and 32) is directly positioned laterally on the edge (38) of the face surface (6) of the rotor (3) in the rotor head (7, 7', 37), in which the cross-section of the recess dimensionally conforms to the discharge of material to be conveyed from the pressure chamber (11, 11') and is predetermined by rotation of the rotor (3).
5. Eccentric screw pump according to at least one of the preceding claims,
   characterized in that,
   the recess (8) in a plan-view section more-or-less depicts a bean-shaped long-hole.
6. Eccentric screw pump according to at least one of the preceding claims,
   characterized in that,
   the rotor-head front surface (9) turned away from the rotor face surface (6) is evenly surfaced (selective) with regard to the disc-shaped design, may be spherically capped and/or provided with a profile featuring at least a vane or other projections for improving the mixture of the material to be conveyed.
7. Eccentric screw pump according to at least one of the preceding claims,
   characterized in that,
   the rotor (3) is of screw design in form of a round thread screw with a large pitch and thread depth, wherein the stator (2) depicts a screw casing and comprises axially consecutive cavities (15, 16, 17) - at least a suction-side inlet cavity (15) and a pressure-side discharge cavity (17) - of a conveyor section (14), wherein between the stator's interior surface (18) and the rotor's exterior surface (19) conveyor chambers (20, 21, 22) a formed through adapted sealing sections (23, 24) between the stator (2) and the rotor (3), wherein the material to be conveyed can be displaced into the conveyor chambers (20, 21, 22) by rotating the rotor (3) inside the cavities (15, 16, 17) of the stator 2 from the suction-side inlet section (4) to the pressure-side discharge (5).
8. Eccentric screw pump according to at least one of the preceding claims,
   characterized in that,
   the conveyor section (14) is preferentially based on two cavity lengths or rather on an ''inlet cavity - cavity - discharge cavity" arrangement (15 - 16 -17).
9. Eccentric screw pump according to at least one of the preceding claims,
   characterized in that,
   the conveyor section (14) is shortened to match the screw flight of the stator (2), wherein the rotor head (7, 7', 37) particularly contributes to positional stabilization of the rotor (3).

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