Stator for an eccentric screw pump

Abstract

A stator (10) for a feed pump, in particular for an eccentric screw pump, wherein the stator (10) comprises a stator body (18) having an accommodation hole (36) for accommodating a rotor (24). It is further provided that the stator body (18) is configured as an elastomer body (20) reinforced at least in sections with a thread inlay (38).

Claims

1. A stator for an eccentric screw pump, the stator comprises: a stator body, the stator body comprising: an accommodation hole configured for accommodating a rotor; a tubular elastomer body reinforced at least in sections with a thread inlay and having an axial first end and an axial second end opposite the axial first end; a first end piece; and a second end piece, wherein: the tubular elastomer body forms an outer surface of the stator body; the first axial end is secured to the first end piece; and the second axial end is secured to the second end piece.

2. The stator according to claim 1, wherein the stator body is helical, and the accommodation hole helically extends through the stator body along the longitudinal axis thereof.

3. The stator according to claim 1, wherein the thread inlay extends in the direction of the longitudinal axis through the stator body.

4. The stator according to claim 3, wherein the thread inlay extends around the longitudinal axis of the stator in the elastomer body in the form of a winding.

5. The stator according to claim 4, wherein the winding of the thread inlay consists of several layers, wherein at least individual layers of the winding are crosswise wound.

6. The stator according to claim 1, further comprising supporting elements provided on the stator body on an outer circumferential surface and distributed along a longitudinal extension of the stator body.

7. The stator according to claim 6, wherein the stator comprises at least one tie rod and the supporting elements provided on the outer circumferential surface of the stator body rest against the at least one tie rod.

8. The stator according to claim 1, wherein the stator comprises at least one tie rod which is connected to the first end piece and the second end piece at axial ends of the stator.

9. An eccentric screw pump comprising a stator according to claim 1.

10. A stator for an eccentric screw pump, the stator comprises: a stator body, the stator body comprising: an accommodation hole configured for accommodating a rotor; an elastomer body reinforced at least in sections with a thread inlay; one or more supporting elements provided on an outer circumferential surface of the stator body and distributed along a longitudinal extension of the stator body; at least one tie rod which is connected to end pieces of the stator adjacent axial ends of the stator body; and wherein the one or more supporting elements provided on the outer circumferential surface of the stator body rest against the at least one tie rod.

11. The stator according to claim 10, wherein the stator body is helical, and the accommodation hole helically extends through the stator body along the longitudinal axis thereof.

12. The stator according to claim 10, wherein the thread inlay extends in the direction of the longitudinal axis through the stator body.

13. The stator according to claim 10, wherein the end pieces of the stator are configured such that the axial first end and the axial second end of the stator body are configured to be seized by the end pieces of the stator.

14. A stator for an eccentric screw pump, the stator comprises: a stator body, the stator body comprising: an accommodation hole configured for accommodating a rotor, the stator body comprises; a tubular elastomer body reinforced at least in sections with a thread inlay and having an axial first end and an axial second end; a plurality of supporting elements provided on the stator body, each supporting element extending from an outer surface of the stator body at a first axial location spaced from a second axial location of at least one other supporting element; and wherein the elastomer body forms an outer surface of the stator body.

15. The stator according to claim 14, wherein the stator comprises at least one tie rod which is connected to end pieces of the stator at adjacent axial ends of the stator body.

16. The stator according to claim 15, wherein the supporting elements provided on the outer circumferential surface of the stator body rest against the at least one tie rod.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following an exemplary embodiment of the present invention is described with reference to the attached drawings, in which

(2) FIG. 1 shows a perspective view of a stator according to a first embodiment of the invention;

(3) FIG. 2 shows a front view of the stator according to FIG. 1;

(4) FIG. 3 shows a side view of the stator according to FIGS. 1 and 2;

(5) FIG. 4 shows a sectional view along the sectional line II-II of FIG. 2;

(6) FIG. 5 shows a sectional view along the sectional line III-III according to FIG. 3;

(7) FIG. 6 shows a detail drawing of section V according to FIG. 5; and

(8) FIG. 7 shows a sectional view of a stator according to a second embodiment of the invention.

DETAILED DESCRIPTION

(9) FIG. 1 shows a perspective view of a stator for a feed pump which is generally denoted by 10.

(10) The stator 10 comprises end pieces 12 and 14 which are connected to each other via tie rods 16 (three tie rods are shown in FIG. 1). The stator body 18 being configured in the form of an elastomer body 20 being at least in sections reinforced with a fiber inlay (not shown) extends between the end pieces 12 and 14.

(11) According to FIG. 1, the end pieces 12 and 14 are configured as multi-part pieces, which will be dealt with in more detail in the following.

(12) A hole 22 through which an end portion 24 of the rotor 26 extends can be seen in the end piece 14.

(13) The rotor 26 can be connected via the end portion 24 to a drive means (not shown), which may consist, for example, of a motor and a universal-joint shaft. When in operation with a feed pump, the rotor 26 can perform an eccentric and rotary motion. A universal-joint shaft for connecting a motor to the rotor 26 can comprise, for example two cardan joints. Furthermore, the connection between the motor and the rotor 26 can be effected via a flexible bending rod.

(14) FIG. 1 further illustrates supporting elements 28 at the elastomer body 20 or the stator body 18, said supporting elements being distributed on the outer circumferential surface 30 of the stator body 18 around and in the direction of the longitudinal axis L. The rotor body 18 is spiral-shaped or helical, wherein the supporting elements 28 are provided on the outer circumference of the helix shape or spiral shape.

(15) The supporting elements 28 are supported against or rest against the tie rods 16. To this end, the supporting elements 28 have a concave contact portion 32. During the operation of a feed pump provided with the stator 10, the feature that the supporting elements 28 rest against the tie rods 16 entails that the stator body 18 is prevented from buckling or bulging due to the pressure exerted by the medium to be conveyed. In other words, the pressure exerted by the medium to be conveyed onto the elastomer body 20 of the stator body 18 is transmitted to the tie rods via the supporting elements 28 and the supporting elements 28 are deformed.

(16) As further illustrated in FIG. 1, the end pieces 12 and 14 are configured as multi-part pieces and comprise end piece members 12a, 12b and 14a, 14b. The end piece members 12a and 12b are connected to each other via fastening means in the form of screws 34, as depicted in FIG. 1. The same is true for the end piece members 14a, 14b, which is hinted at in FIG. 1.

(17) FIG. 2 shows a front view of the stator 10.

(18) FIG. 2 depicts the end piece members 12a and 12b of the end piece 12 as well as the end piece members 14a and 14b of the end piece 14, which are connected to each other via screws 34 just as the end piece members 12a and 12b.

(19) FIG. 2 reveals the helical or spiral shape of the stator body 18, wherein the supporting elements 28 are arranged to be distributed over the radius of the helical shape of the stator body 18 in its longitudinal direction. Each of the supporting elements 28 is supported on the tie rods 16 extending between the end pieces 12 and 14.

(20) FIG. 3 shows a side view of the stator 10.

(21) FIG. 3 illustrates the end piece 14 and the pot-like end piece member 14b as well as the hole 22 configured therein. The rotor 26 is accommodated in an accommodation hole 36 or in a recess 36 in the stator body 18. The entrance of the hole 36 in the stator body 18 or the elastomer body 20 has an elongate extension transverse to the longitudinal axis in order to enhance the eccentric motion of the rotor 26.

(22) FIG. 3 further shows the helical structure WS of the recess or hole 36 in the direction of the axis L.

(23) FIG. 4 shows a sectional view along the sectional line II-II of FIG. 2.

(24) FIG. 4 illustrates the end piece 12 or rather the end piece member 12b, the screws 34 connecting the end piece members 12a and 12b to each other (FIG. 2) and the rotor 26 extending through the hole 36.

(25) The supporting elements 28 rest against the tie rods 16 via their contact portions 32.

(26) FIG. 4 shows for the first time the thread inlay 38 which is embedded into the elastomer body 20 of the stator body 18 in order to reinforce the elastomer body 20.

(27) In the sectional view according to FIG. 4, the hole 36 in the stator body 18 through which the rotor 24 extends has again an elongate shape due to the spiral or helical shape of the stator body 18.

(28) FIG. 5 shows a sectional view along the sectional line of FIG. 3.

(29) Eventually, FIG. 5 clearly depicts the thread inlay 38 which extends in the direction of the longitudinal axis L of the stator 10 through the elastomer body 20 of the stator body 18 and/or is embedded in the elastomer body 20.

(30) The axial ends of the stator body 18 are respectively seized by the end piece members 12a, 12b and 14a, 14b in order to fix the stator body 18 to the end pieces 12 and 14 and keep in shape the stator body 18 together with the tie rods 16. Recesses 12c and 14c accommodating the axial ends of the stator body 18 are provided in the end piece members 12b and 14b for fixing the axial ends of the stator body 18. The axial ends of the stator body 18 are seized or clamped between the respective end piece members 12a, 12b and 14a, 14b via the screws 34.

(31) The hole 36 or the recess 36 extends through the stator body 18 in the direction of the longitudinal axis L thereof The inside of the recess 36 is also provided with a helical or spiral-shaped contour. The rotor 26 in turn extends through the recess 36, as illustrated in FIG. 5. The rotor 26 is likewise spiral-shaped or helical.

(32) The helical shape of the rotor 26 and the helical shape of the recess 36 in the elastomer body 20 of the stator body 18 cooperate to convey the medium to be conveyed since conveyor chambers are formed by the helical shape of the stator body 18 and the rotor 26, which enable a continuous and pulsation-free conveyance of the material to be conveyed by the pump. Due to its helical shape and its eccentric drive, the rotor 26 can contact or also deflect specific portions of the stator body 18 in order to form one or more conveyor chambers.

(33) Since it is often viscous, highly viscous and abrasive media, such as oil, fat and mud-like wastewater, that are conveyed with pumps of this type, a high pressure is exerted onto the stator body 18 during the operation of a feed pump or an eccentric pump. This pressure can be transmitted to the tie rods 16 by deformation of the supporting elements 28, whereby the stator body 18 is prevented from bulging or buckling as well as twisting on account of the pressure of the medium to be conveyed. The medium to be conveyed enters the stator body 18 at the end piece 14 (FIG. 5right side in the direction of the longitudinal axis L), is conveyed through the stator body 18 by means of the motion of the rotor 26 and flows through the hole 36 out of the stator via the end piece 12 or rather the end piece member 12a with its tube like connecting piece (FIG. 5left side in the direction of the longitudinal axis L).

(34) The rotor 26 comprises a hole 40 for the purpose of fixation to a universal-joint shaft or the like.

(35) FIG. 6 shows a detail view of the detail V of FIG. 5.

(36) This view clearly illustrates the thread inlay 38 which is enclosed in the elastomer of the elastomer body 20 of the stator body 18.

(37) When producing the stator body 18, in contrast to the state of the art, no connection between the elastomer and a metal tube has to be made. In the stator body 18 according to the invention, the thread inlay 38 is embedded in an elastomer body 20 and the elastomer is subsequently vulcanized whereby a connection between the elastomer and the thread inlay is effected.

(38) In the following, a second embodiment of the stator according to the invention is described wherein similar components having the same effect are provided with the same reference signs but prefixed with the figure 1.

(39) The stator 110 according to the second embodiment comprises end pieces 112 and 114. The end piece 114 comprises a hole 142 through which the medium to be conveyed enters the stator 110. The end piece 114 further comprises an accommodation hole 122 which accommodates the end portion 124 of the rotor 126 or in which the end portion 124 of the rotor 126 is supported. The rotor 126 is rotatably supported in the accommodation hole 122 but cannot perform any eccentric motion due to its rigid support in the hole 122. The end portion 124 of the rotor 126 is tubular whereas the portion of the rotor 126 accommodated in the hole 136 of the stator body 118 or of the elastomer body 120 is helical.

(40) In addition to the accommodation portion 144 comprising the hole 136, the stator body 118 comprises a retainer portion 146 which radially surrounds the accommodation portion 144. The accommodation portion 144 and the retainer portion 146 are connected to each other via a connection portion 148. The connection portion 148 extends at an angle to the longitudinal axis L, whereas the accommodation portion 144 and the retainer portion 146 extend in the direction of the longitudinal axis L. The connection portion forms a part of the accommodation hole 136 of the elastomer body 120. A first end 150 of the elastomer body 120 is clamped between the end piece member 112a and 112b of the end piece 112. The second end 152 of the elastomer body 120 is provided radially inwards of the first end 150 and has no connection to the end pieces 112a, 112b. The second end 152 and the accommodation portion 144 are movable. The accommodation portion 144 is forced by the rotating rotor 126 to perform an eccentric motion during operation, said eccentric motion being necessary for the pumping step.

(41) The elastomer body 120 comprises the thread inlay 138 which extends completely through the elastomer body 120 and is also seized in the end piece members 112a and 112b.

(42) The stator 110 comprises a tubular portion 154 which extends between the end pieces 114 and 112. The retainer portion 146 of the elastomer body 120 rests against the tubular portion 154. The connection portion 148 of the elastomer body 120 extends from the retainer portion 146 radially inwards and merges into the accommodation hole 136 and connects the retainer portion 146 to the accommodation portion 144 having a spiral-shaped or helical contour. The accommodation portion 144 accommodates the rotor 126 at least in sections.

(43) The stator 110 according to this embodiment is particularly configured for pumps in which the rotor 126 is rigidly arranged and only rotates around the longitudinal axis L. The rotor 126 cannot perform an eccentric motion. In this type of pump, the eccentric motion necessary for the pumping operation is achieved by the accommodation portion 144 of the stator body 118 which is deflected by the rotating, helical rotor 126 in operation and thus can perform an eccentric motion. The eccentric motion of the deflectable accommodation portion 144 is also made possible on account of the movable end 152 which is not fixed to the stator 110 or the end piece 112. Two conveyor chambers can be formed between the rotor 126 and the accommodation portion 144 by means of the deflectable accommodation portion 144 in order to convey the medium to be conveyed through the stator 110.

(44) In other words, the eccentric motion necessary for the pumping operation is achieved in this type of pumps by the rotary motion of the rotor 126 and the deflection of the accommodation portion 144 of the elastomer body 120 relative to the longitudinal axis L.