DE102011101648A1 - Screw machine e.g. double-flow screw pump, for pumping of e.g. fluid, has spindles accommodated with profile packages in casing, where fixed gap is formed among spindles and casing, and gap adjustment unit adjusting gap - Google Patents

Abstract

The machine i.e. screw pump (1), has a drive spindle (4) and a counter-spindle (5) accommodated with profile packages (6, 7) in a pump casing (2), where a fixed gap is formed among the spindles and the pump casing. A gap adjustment unit enables adjustment of the gap. The gap adjustment unit comprises a screw (12), which is screwed into a threaded bore (14) of a housing module (3), where the housing module comprises housing module portions. The gap adjustment unit comprises a position screw thread or a guide cylinder. The gap adjustment unit comprises a sensor for detecting the gap. The sensor is selected from one of inductive sensor, magnetic field sensor and Hall sensor.

Description

The invention relates to a screw machine, in particular a screw pump, with a pump housing, in which a drive spindle and at least one counter-rotating spindle are received with intermeshing profile packets, wherein between the spindles and the pump housing, a fixed gap width is provided.

Screw pumps are used to convey fluids and multiphase mixtures of various types. The drive spindle and the at least one running spindle have delivery profiles, which together with the pump housing form displacement chambers through which the fluid is conveyed axially from the suction side to the pressure side. The two or more spindles are coupled together by gears, alternatively they may be driven over the profile flanks or driven by synchronized motors. Optionally, a housing insert is provided in the pump housing, in which the spindles are accommodated. The pressure chamber formed in the interior of the housing or of the housing insert can be sealed by means of seals. The spindles have several bearings, which limits their deflection. Such a screw pump is from the DE 10 2005 037 118 B3 known.

In conventional screw pumps, a certain gap between the spindles and the pump housing is calculated during the design phase and assigned to the components. The design of the gap width takes place with regard to the delivery task and the intended operating point, the efficiency of the screw pump, however, can be optimized only for a single operating point. As a result of the action of the conveyed media, which may also contain solids in part, an increase in the gap width can occur with increasing service life, which leads to a reduction in the delivery rate. To counteract this negative effect, the aim is to operate the screw pump at an increased speed, but an increase in speed for process reasons is not always possible. As soon as the wear, which manifests itself by an increased gap width, has exceeded a certain limit, it is therefore necessary to exchange at least the profile packs and the corresponding associated housing parts.

The invention is therefore based on the object, a screw machine, in particular a screw pump to specify, which has an increased life and can be used flexibly with high efficiency for media with different viscosity.

To solve this problem is provided according to the invention in a screw machine, especially in a screw pump, of the type mentioned that it has a means for adjusting the gap width.

The invention is based on the recognition that the life of a screw pump can be significantly increased by providing a way to adjust or readjust the gap width between the spindles and the pump housing. Accordingly, with increasing wear, the gap width adjusted, that is reduced, so that there is a similar gap width as in a new screw pump. This small gap width allows operation of the screw pump at a desired operating point where the efficiency or other parameter is optimal. In addition, the reduction in the gap width leads to an increase in the delivery rate, so that it is possible to dispense with a speed increase associated with disadvantages.

To implement the solution according to the invention, provision may be made for the means for adjusting the gap width to include a conical drive spindle and at least one conical running spindle which are axially displaceable. Preferably, the gap width is substantially constant, therefore, the spindle base is preferably also formed conical. In this variant, the two or more spindles are axially displaceable relative to the pump housing. By shifting the desired adjustment results to adjust the gap width between the spindles and the pump housing. In addition to the possibility of readjustment after a certain period of operation allows the means for adjusting the gap width and a precise adjustment of a new screw pump to a desired operating point, the adjustment can be made already at the manufacturer.

Optionally, it can be provided that the normally exactly parallel spindles enclose a small angle with each other, so that the spindles run towards each other or apart. This angle can be up to 3 °, and possibly also up to 5 °.

In the screw pump according to the invention, it is particularly preferred that the drive spindle and the at least one running spindle are arranged in a housing insert received in the pump housing. In this variant of the invention, the means for adjusting the gap width for adjusting the gap between the spindles and the housing insert is provided. Accordingly, not the gap between the Spindles and the pump housing, but between the housing insert and the spindles set. The particular advantage of this variant is the fact that the housing insert with the spindles in the context of overhaul can be relatively easily replaced when the wear limit is reached. The pump housing and other components, such as a drive of the pump can be maintained without further change, by replacing only the housing insert, which is also referred to as a liner, together with the spindles.

A particularly simple and practical way to adjust the gap width results when the housing insert is conical and axially displaceable. The adjustment of the gap width can preferably be realized only by axial displacement of the housing insert, so that the spindles remain stationary. Since only the housing insert is to be adjusted by moving, this variant can be realized with comparatively little effort. In principle, however, it is also possible for both the spindles and the housing insert to be axially displaceable, although the sole adjustment of one of the two components is sufficient to implement the adjustment possibility of the gap width.

It is particularly expedient if the housing insert and the spindles have the same cone angle in order to realize an at least approximately constant gap width over the length of the profile package of the spindles. The cone angle can vary, wherein preferably the profile package and the pump housing or the housing insert have the same cone angle. In principle, however, pairings are also conceivable in which the pump housing or the housing insert and the spindles have at least slightly different cone angles. As a result, different gap widths at different points of the profile package are possible.

To facilitate assembly and disassembly, it may be provided in the screw pump according to the invention that the housing insert has two or more Gehäuseinschubabschnitte. The housing insert may preferably be divided in the circumferential direction, alternatively or additionally, a housing insert consisting of a plurality of housing insertion sections arranged axially one behind the other would also be conceivable.

According to a development of the screw pump according to the invention, provision may be made for the means for adjusting the gap width to have an adjusting thread or a guide cylinder. The adjusting thread defines an axis along which the displacement of the pump housing, the housing insert or the spindles takes place. Alternatively, a guide cylinder may be provided, whose longitudinal direction also defines the direction of displacement. Adjusting the gap width can be done manually or by means of an electric, mechanical or hydraulic drive, preferably a hydraulically controlled piston, a servomotor or an adjusting spindle. If the adjustment of the gap width should be made only with occurred wear, it is sufficient, for. B. to provide a set screw, which is used in the production of adjusting the desired gap width. If, after a certain period of wear or a change in viscosity deterioration of the capacity has been found, the slot width can be manually adjusted by means of the adjusting thread, that is reduced to realize a similar gap width as in a new pump. On the other hand, it is also conceivable to automatically monitor and adjust the gap width, in this case, the screw pump may have one of the aforementioned drives to set the gap width by axial adjustment of the spindles and / or the pump housing or the housing insert.

In order to enable automatic adjustment of the gap width, the means for adjusting the gap width in the screw pump according to the invention may comprise at least one sensor for detecting the gap width or the position of an adjustable component. The sensor can either directly detect the gap width, alternatively it is sufficient if the sensor z. B. can accurately detect the position of the sliding housing insert.

In a further embodiment of the invention, it may be provided that the screw pump has a control or regulating device or is coupled thereto, by means of a certain gap width is controlled or regulated. The control or regulating device preferably has at least one sensor for detecting the gap width or the position of an adjustable component in order to set the desired, predetermined gap width on the basis of the detected gap width.

It is particularly preferred that the regulating device for adjusting the gap width is formed as a function of the viscosity of a conveying medium and / or the pressure of the conveying medium. In addition, other control parameters or influencing variables are conceivable, for example the type of medium, the temperature of the medium or the flow rate of the medium. It is also conceivable that the screw pump is to be used for different media that pull different optimal gap widths. By inventively provided means for adjusting the gap width, the Screw pump thus optimally adjusted for each fluid.

All of the technical features mentioned in this application can also be part of the invention in different combinations, in particular the position and orientation of the cones relative to one another or the arrangement of the components.

Further advantages and details of the invention will be explained below with reference to embodiments with reference to the drawings. The drawings are schematic representations and show:

1 a detail of a first embodiment of a screw pump according to the invention in a sectional view;

2 a detail of a second embodiment of a screw pump according to the invention in a sectional view;

3 a sectional view of the drive spindles and the housing insert;

4 the sectional view of 3 after setting the gap width;

5 a further embodiment of a screw pump according to the invention in a cross-sectional view of the spindles;

6 in the 5 shown screw pump after adjusting the gap width; and

7 an embodiment of a double-flow screw pump according to the invention.

1 shows as an example of a screw machine, the essential components of a screw pump 1 with a pump housing 2 , a housing insert 3 in which a drive spindle 4 and an opposite running spindle 5 with interlocking profile packages 6 . 7 are arranged. The two profile packages 6 . 7 mesh with each other, whereby axially moving pressure chambers are generated to promote a medium from a suction side to a pressure side. The basic structure of such a screw pump is for example from the DE 10 2005 037 118 B3 known so that it will not be discussed further here.

The drive spindle 4 and the spindle 5 are in plain bearings 10 . 11 mounted axially and radially, the bearing is opposite to the inside of the housing insert 3 sealed pumping space formed sealed. In other embodiments, a bearing can be provided in rolling bearings. Likewise, the seal is only optional and can be omitted in certain designs. The drive spindle 4 and the spindle 5 optionally have gear wheels (not shown), whereby the meshing movement of the profile packages of the drive spindle 4 and the spindle 5 is realized.

In the 1 shown screw pump 1 has a means for adjusting the gap width. The term "gap width" in this context refers to the distance between the inside of the housing insert 3 and the profile packages of the drive spindle 4 or the running spindle 5 , This gap width is set within the design to an operating range or operating point of the screw pump 1 determine where it works with optimum efficiency. The means for adjusting the gap width can already be used in the context of manufacturing to set the desired gap width exactly, as well as the gap width can be readjusted at a later date when wear-related changes have occurred.

The means for adjusting the gap width comprises a screw in the illustrated embodiment 12 that with their end section 13 in a threaded hole 14 of the housing insert 3 screwed. The screw 12 passes through a hole 15 a lid 16 the screw pump 1 , If the screw 12 into the threaded hole 14 is screwed, the housing insert 3 moved axially. The inside of the case 2 forms a guide for the axial displacement of the housing insert 3 , So that a certain axial position of the housing insert 3 permanently maintained, the position of the screw can 12 through a lock nut 17 located on the outside of the lid 16 supported, secured. Between locknut 17 and the lid 16 is a screw seal 18 intended. In other versions, the adjusting screw can be sealed with O-rings. In the circumferential direction of the screw pump 1 can have several screws 12 be arranged to an exact, axial displacement of the housing insert 3 sure.

2 shows a second embodiment of a screw pump 26 wherein identical components are given the same reference numerals as in the previous embodiment. Inside the screw pump 26 is a sensor 19 arranged to detect the axial position of the housing insert 3 is trained. The sensor 19 is designed as a non-contact sensor, it may be an inductive sensor, a magnetic field sensor, a Hall sensor or another sensor, which allows a distance measurement. The sensor 19 is with a likewise schematically illustrated control device 20 connected, which is part of the screw pump 26 or alternatively may be formed separately therefrom. By the control device 20 Can the gap width between the profile packages and the inside of the housing insert 3 be controlled so that a certain, constant gap width is maintained. There are also other designs conceivable in which the control device 20 is switched on only at longer intervals, after which it is checked whether a readjustment of the gap width is required. If the gap width z. B. has been increased by meanwhile occurred wear is by means of a drive 21 an adjusting spindle 22 turned to the chassis slot 3 to move axially. Because both the inside of the housing insert 3 as well as the profile packages of the drive spindle 4 and the spindle 5 are conical, performs an adjustment of the adjusting spindle 2 in one direction to increase the gap width, an adjustment in the opposite direction leads to a reduction of the gap width. In another mode, the control device 20 be permanently switched on and continuously monitor the gap width and readjust if necessary.

In the 1 and 2 are the profile packages 6 . 7 designed so that its diameter decreases in the flow direction of the medium. However, it is also conceivable reverse embodiments in which increases the cone diameter in the flow direction.

3 shows a sectional view of the profile packages 6 . 7 the drive spindle 4 and the spindle 5 and the housing insert. The two parallel profile packages 7 . 6 mesh with each other, whereby axially moving pressure chambers are formed to promote the medium from the suction side to the pressure side. In the in 3 The view shown is the gap width S between the outside of the profile packages and the inner wall of the housing insert 3 comparatively large, which leads to a reduction of the capacity. By an axial displacement of the housing insert 3 , either manually z. B. by a screw or automatically, z. B. by a drive spindle connected to a drive, the gap width S can be reduced, this state is in 4 shown. 4 shows the same section as in 3 after the displacement of the housing insert 3 in the axial direction. The chassis slot 3 has an approximately constant outer diameter or a constant outer contour, in the interior, however, it is conically shaped, so that when it is displaced in the axial direction, the gap width S is reduced. In the 4 shown reduced gap width causes an increase in the capacity of the screw pump 1 ,

5 shows a further embodiment of a screw pump in a cross-sectional view of the spindles. The screw pump comprises a drive spindle 23 and a running spindle 24 in a housing slot 25 are included. The spindles 23 . 24 are conically shaped, unlike in the previous embodiment, the means for adjusting the gap width causes an axial displacement of the spindles 23 . 24 , To the in 5 To reduce the shown comparatively large gap width S, the drive spindle 23 and the spindle 24 moved axially, causing the in 6 shown position results. 6 shows the chassis slot 25 with the spindles 23 . 24 cut at the same axial position. Due to the axial displacement of the spindle 23 . 24 The gap width S was considerably reduced, resulting in the desired increase in capacity.

7 shows an embodiment of a twin-screw pump 37 with a pump housing 27 in which a drive spindle 28 and an opposite running spindle 29 are arranged. The drive spindle 28 has two opposite profile packages 30 on, the spindle 29 has two opposite profile packages 31 on. The profile packages 30 . 31 Together with corresponding pump housing sections form pressure chambers, so that a conveyed medium continuously axially to the center of the screw pump 37 promoted. The medium leaves the screw pump 37 via an outlet 32 ,

In accordance with the foregoing embodiments, a means for adjusting the gap width is provided, which is a screw 33 comprising, with its end portion in a threaded bore of a housing insert 34 screwed. The axial adjustment of the housing insert 34 takes place analogously to the preceding embodiments. In addition, on the opposite side of the screw pump 37 another screw 35 provided to the in 7 right housing insert 36 to be adjusted axially. Accordingly, the left housing insert 34 and the right-hand chassis slot 36 be set independently or readjusted.

In other embodiments, a non-contact sensor may be provided, which allows a distance measurement or a position determination and which may be connected to a control device. In this way, a certain gap width can be maintained by means of the control device.

In the context of the invention, various variants are possible, for example, the drive of the means for adjusting the gap width be implemented mechanically, electrically or hydraulically. It is also conceivable to realize the gap width via a peelable metal, for this purpose, an axial end of the housing insert is removed so far until a desired gap width is reached. Subsequently, however, no adjustment in the opposite direction is possible.

The cone angle of the spindles and the housing insert can be identical, but it is also conceivable that the components have different cone angles, whereby a wedge-shaped gap is established. This effect can be used to account for deflection of the spindles.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005037118 B3 [0002, 0026]

Claims (10)

Screw machine, in particular screw pump, with a pump housing, in which a drive spindle and at least one counter-rotating spindle are received with interlocking profile packs, wherein between the spindles and the pump housing, a fixed gap width is provided, characterized in that the screw pump ( 1 . 26 . 37 ) has a means for adjusting the gap width. Screw pump according to claim 1, characterized in that the means for adjusting the gap width a conical drive spindle ( 4 . 23 . 28 ) and at least one conical running spindle ( 5 . 24 . 29 ), which are axially displaceable. Screw pump according to claim 1 or 2, characterized in that the drive spindle ( 4 . 23 . 28 ) and the at least one running spindle ( 5 . 24 . 29 ) in one in the pump housing ( 2 . 27 ) received housing insert ( 3 . 34 ) are arranged. Screw pump according to claim 3, characterized in that the housing insert ( 3 . 34 ) is conical and axially displaceable. Screw pump according to claim 3 or 4, characterized in that the housing insert ( 3 . 34 ) has two or more housing insertion portions. Screw pump according to one of the preceding claims, characterized in that the means for adjusting the gap width has a setting thread or a guide cylinder. Screw pump according to one of the preceding claims, characterized in that the means for adjusting the gap width manually or by means of an electric, mechanical or hydraulic drive, in particular by means of a hydraulically controlled piston, a servomotor or an adjusting spindle, can be actuated. Screw pump according to one of the preceding claims, characterized in that the means for adjusting the gap width at least one sensor ( 19 ) for detecting the gap width or the position of an adjustable component. Screw pump according to one of the preceding claims, characterized in that it comprises a control or regulating device ( 20 ) or is coupled thereto, by means of a certain gap width is controlled or regulated. Screw pump according to one of the preceding claims, characterized in that the control device ( 20 ) is designed for adjusting the gap width as a function of the viscosity of a pumped medium and / or the pressure of the pumped medium.

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