SYSTEM FOR CLAMPING A SUBPIPE OF A TANK PUMP IN AN END FITTING

Description

[0001] The invention relates to a tank unit with a tank pump which comprises an immersion tube, the free end of which is clamped in an end fitting by means of clamping bodies according to the preamble of claim 1. The invention further relates to a corresponding tank pump according to the preamble of claim 12 and a method for fixing the immersion tube or the free end of the immersion tube in the end fitting according to the preamble of claim 14. TECHNICAL BACKGROUND

[0002] In many areas of technology, tanks are used for the storage and / or temporary storage of fluids; usually for storage and / or transport. To discharge the fluids from the tank and / or to supply fluids to it, pumps are typically used, with the pumping action preferably reaching the bottom of the respective tank. This makes it possible to discharge and / or supply the respective fluids from this tank in a defined and controlled manner.

[0003] Tank pumps with a long immersion pipe are particularly suitable for larger tanks. The immersion pipe can be designed so that its free end reaches to the bottom or at least close to the bottom or to a desired lowest withdrawal point in the tank. Where tank contents consist of fluids containing solids and with low to very high viscosities, progressing cavity pumps are used. Progressing cavity pumps are also suitable for aggressive or abrasive media. For this purpose, a tank pump designed as an eccentric screw pump with an immersion pipe is suitable, with at least the stator of the eccentric screw pump preferably being designed continuously in the immersion pipe up to the free end of the immersion pipe. This means that the motor of the tank pump does not have to be immersed in the tank or only partially.The fluid in the tank can be introduced, which naturally results in various advantages, such as improved accessibility and reduced protective measures against fluid ingress. Such a tank pump, in the form of an eccentric screw pump with a submersible tube, is available in the . Fig. 1 and Fig. 2 shown. The Fig. 1 shows the complete tank unit 1, whereby the tank pump 3 can also be seen in its entirety. Fig. 2 shows only the section of the free end of the immersion tube when inserted into an end socket 6.

[0004] The motor 102 of the tank pump 3 (see Fig. 1) is arranged outside, preferably above, a tank 2. Directly or indirectly connected to the motor itself is a dip tube 5, which is preferably constructed in several parts. In the example shown, the stator 4 of the eccentric screw pump, which is driven by the motor 102, is located in this dip tube 5. The stator 4 of the eccentric screw pump preferably extends to the free end 15 of the dip tube 5.

[0005] Especially where eccentric screw pumps are used as submersible pumps, the free end 15 of the immersion pipe 5 must be attached to the desired lowest extraction point of the tank, preferably at the bottom of the tank 2.

[0006] For this purpose, an end fitting 6 is usually used, which is itself fixed at the desired lowest withdrawal point in the tank 2 and into which the free end 15 of the immersion tube 5 is at least partially inserted. This end fitting 6 with the inserted free end 15 of the immersion tube 5 is also Fig. 1 and Fig. 2 shown.

[0007] It should be mentioned that the immersion tube 5 in Fig. 2 is formed at least in sections by the stator housing 21 of the eccentric screw pump. This is shown only as an example. Generally, the stator housing 21 does not even have to form the immersion tube in sections. It is also possible and often expedient for the stator housing to be enclosed by an external immersion tube, preferably essentially in the form of a tube.

[0008] With the help of this end fitting 6, the immersion tube 5 is essentially "clamped," which primarily prevents the free end 15 of the immersion tube 5 from being caused to vibrate due to the rotating movement of the eccentric screw pump's rotor, to such an extent that the tank pump 3 and / or the motor 102 of the tank pump 3 are damaged by the resulting high dynamic forces. Furthermore, this clamping also prevents unstable deflection of the free end 15 of the immersion tube 5.

[0009] The immersion tube 5 itself is often made of several parts due to its sometimes great length, as mentioned above, with the lower part of the immersion tube often receiving additional support from one or more support rings 17 with support struts 20. These support struts, which are clamped to a support ring 17 at the free end 15 of the immersion tube 5, are also Fig. 1 shown. STATE OF THE ART

[0010] However, the described "insertion" of the free end 15 of the immersion tube 5 into the end fitting 6 usually turns out to be very difficult and cumbersome and can often be described as "threading".

[0011] Due to the fact that the end nozzle 6 is usually located in a poorly visible area, the length of the immersion tube 5 combined with the poor accessibility to the end nozzle 6, but also possible contamination on the free end 15 of the immersion tube 5 or on the end nozzle 6, and the tolerances resulting from manufacturing, inserting the free end 15 of the immersion tube 5 into the end nozzle 6 is difficult for a variety of reasons. However, even if the insertion of the free end 15 of the immersion tube 5 into the end nozzle 6 was successful, the bearing there is in most cases not satisfactorily designed.

[0012] Currently, for example, it is common practice for an O-ring receptacle 101 to be attached to the free end 15 of the immersion tube 5. This is Fig. 2shown as an example. In this O-ring holder 101, an O-ring 103 is guided circumferentially, with a part of the O-ring holder 101 naturally protruding from the circumferential groove of the O-ring holder 101. This part protruding from the groove is thus used to fill the radial gap between the O-ring holder 101 and the end piece 6. For this purpose, the O-ring holder 103 is elastically deformed when the free end 15 of the immersion tube 5 is inserted into the end piece 6, which on the one hand compensates for a certain tolerance in the annular gap mentioned. On the other hand, a positive connection is created here between the O-ring holder 101 and the end piece 6. The disadvantages of this type of insertion are obvious. The O-ring holder 103 serves more as a damper and is only suitable to a limited extent for implementing a correct fixation.Compensation of tolerances due to elastic deformation is also only partially achieved here, since only a small portion of the O-ring 103 protrudes from the groove, and even insertion into the end piece 6 is not significantly facilitated. Furthermore, there is always a risk of plastic deformation of the O-ring 103 due to shearing during the insertion process or due to aging of the material. Furthermore, the very soft bearing creates vibrations that lead to increased wear on the components, especially the tank pump 3, which in turn requires a significantly more massive design of the entire system and especially the tank pump 3 (especially the tank pump motor).

[0013] Another currently practiced option for connecting the free end 15 of the immersion tube 5 to the end fitting 6 is by means of PTFE washers. These are attached to the free end 15 of the immersion tube 5 in a similar way to the O-ring seal. They are essentially cold-formed when inserted into the end fitting 6, thus compensating for the tolerances in the annular gap between the end fitting 6 and the immersion tube 5. In this case, a significantly higher insertion force is naturally required, and the resulting bearing is significantly stiffer than with the O-ring seal. However, the bearing is usually too stiff, resulting in only a very slight damping effect. Furthermore, this type of connection is very difficult to remove, making access to the system difficult, especially for maintenance, even after the tank pump 3 has been installed.

[0014] In general, it can therefore be stated that vibrations arise during operation of the vertically mounted tank pump 3, which place a strain on the on-site tanks, the building, and the pump system itself. Due to the on-site installation tolerances between the end nozzle 6 and the immersion pipe 5 (primarily deviations in coaxiality and the angle of alignment), an appropriate compensation potential must also be provided for the tank pump 3 and its immersion pipe 5. A completely fixed connection between the end nozzle 6 and the immersion pipe 5 is not practical for reasons of maintenance of the tank pump 3 and accessibility to the tank 2. The existing solutions generally do not make it much easier to insert the immersion pipe 5 into the end nozzle 6, and in addition, the resulting bearings are usually either too rigid or too soft. In most cases, the entire system is therefore either too rigid to reduce the vibrations, or too soft to allow easier insertion into the end nozzle 6.to compensate for the tolerances in the annular gap between end nozzle 6 and immersion tube 5. THE UNDERLYING TASK

[0015] In view of this, the object of the invention is to provide a means by which a good fixation of the dip tube in the end piece is facilitated. THE INVENTIVE SOLUTION

[0016] According to the invention, this problem is solved by the features of the first main claim. Furthermore, independent claim 12 claims a tank pump, and claim 14 claims a method whose features or method steps also solve the aforementioned problem.

[0017] For this purpose, a tank unit consisting of at least one tank and a tank pump submerged in the tank, i.e., protruding from the top of the tank, is proposed. As already mentioned, a "tank" is understood here as a storage and / or intermediate storage facility for liquids with or without a solid content or—in a broader, but not preferred, sense—for other pumpable fluids. Pumpable fluids are fluids capable of flowing from a tank under the influence of gravity into the intake area of ​​a pump located at the bottom of the tank.

[0018] In some cases, these liquids or fluids contain an abrasive solid content.

[0019] In some cases the fluids are highly viscous, to the extent that they can be described as pasty, possibly with a viscosity between 10 3< mPas or 10 4< mPas on the one hand and 10 6< mPas or even 10 7< mPas on the other hand, at 20°C.

[0020] The tank pump in question is preferably designed as an eccentric screw pump with a submersible tube that preferably reaches down to the lowest discharge point of the tank, which preferably represents the tank bottom. The stator of the eccentric screw pump extends deep into the submersible tube, usually even to the free end of the submersible tube. The motor of the tank pump is preferably mounted vertically, i.e., so that the motor shaft axis runs essentially parallel to the axis of the submersible tube. The "tank pump" thus comprises the eccentric screw pump and the submersible tube, with the eccentric screw pump itself comprising the stator, the rotor, and the drive motor. The submersible tube itself can be designed in several parts, with bracing consisting of several threaded rods being provided in the lower area of ​​the submersible tube.With their help, axial preload can be applied to the stator lining via at least one front-end support ring, for example in order to compensate for its wear.

[0021] As already mentioned, an end fitting is attached to the lowest extraction point of the tank, into which the dip tube or the free end of the dip tube is at least partially inserted. At least one, or preferably several, clamping elements are provided in the area of ​​the free end of the dip tube. "In the area of ​​the free end of the dip tube" here means that these clamping elements are either attached to the free end of the dip tube itself or, preferably, to a support ring, e.g., of the type already mentioned above, which is itself attached to the free end of the dip tube. It is therefore advisable for this support ring to function both as a receptacle for the at least one clamping element and as a receptacle for at least one support strut.

[0022] This tank system according to the invention is characterized in that the at least one clamping body is designed such that, in its relaxed position, it has at least one wedge section which, as the free end of the dip tube is pushed into the end piece, penetrates into the radial gap between the end piece and the free end of the dip tube, and in that the at least one clamping body is designed such that, as the free end of the dip tube is pushed completely into the end piece, it rotates and thereby clamps the free end of the dip tube in the end piece.

[0023] The at least one clamping body is thus attached in the area of ​​the free end of the dip tube, where it can be pushed into the end nozzle with the free end of the dip tube. Before insertion or in the unloaded state, this has at least one wedge section which, on the one hand, facilitates insertion and, on the other hand, effects an initial bracing combined with centering or pre-centering. This occurs because this wedge section penetrates into the radial gap between the dip tube and the end nozzle during the insertion process. In addition, the clamping body is designed such that it rotates during the complete insertion process such that a correct clamping effect is achieved between the dip tube or the support ring on the dip tube and the end nozzle.

[0024] This allows the tank pump and / or the immersion tube to be easily centered, the annular gap between the immersion tube and the end fitting is compensated accordingly, and assembly is simplified. This is because, on the one hand, significantly reduced assembly force is required compared to the PTFE washers discussed above, and, on the other hand, the clamping elements can bridge a significantly larger annular gap than the O-rings discussed above. Above all, the at least one wedge section assists with "threading" into the end fitting, and the rotational movement of the clamping element leads to the intended, high clamping force. The bearing can thus be designed so that it is neither too soft nor too rigid, allowing for close-tolerance, non-fixed centering. This type of bearing can also compensate for any angular misalignment that may arise due to offset installation.Dynamic forces and stresses, especially on the tank pump, as well as vibrations are reduced or even eliminated during operation and / or significantly less massive and therefore cheaper tank pumps can be used.

[0025] Another advantage is that the centering and / or fastening of the immersion tube according to the invention can be removed and reinstalled in many cases without the need for new parts, such as a spare PTFE washer or a new cord seal. This significantly simplifies the periodic removal and reinstallation of the progressing cavity pump for the purpose of readjusting the somewhat worn stator lining, as described above.

[0026] The disassembly of this type of connection is also made easier and there are no increased requirements for the installation space, since the compensating system compensates for the axis offsets. PREFERRED TRAINING

[0027] There are a number of ways to design the invention in such a way that its effectiveness or usefulness is further improved.

[0028] A preferred embodiment of the invention consists in the clamping body being elastic enough to compensate for tolerance- or contamination-related dimensional deviations in the radial gap between the free end of the dip tube and the end piece, essentially through its own, preferably elastic, deformation. This provides an additional compensation option, both to facilitate the insertion of the dip tube into the end piece and to ensure the proper connection between the dip tube and the end piece in different installation situations.

[0029] Furthermore, it is particularly preferred if the at least one clamping body is designed at least substantially as a prism, preferably as a four-sided prism with a triangular-segment cross-section. This "triangular-segment cross-section" can be understood analogously to a trapezoidal cross-section. In this case, the clamping body preferably has an extension perpendicular to the plane of the triangular-segment cross-section, i.e., a thickness of > 1 mm, more preferably > 5 mm. Furthermore, the clamping body or the prism is preferably designed such that it has a triangular base surface and a triangular-segment surface substantially parallel to the base surface, wherein the connecting surfaces form the converging triangular leg surfaces from the triangular base surface toward the triangular-segment surface.The triangle base area is therefore the area on the longer parallel side of the triangle segment cross-section and the triangle segment area is the area on the shorter parallel side of the triangle segment cross-section.

[0030] A triangular leg surface, preferably the one facing the end fitting during insertion, forms an insertion wedge with the triangular base surface, which facilitates the insertion of the clamping body into the radial gap, even when the dip tube is inserted from the top of the tank, which makes threading it in even more difficult. This shape also facilitates elastic deformation of the clamping body through bending, which is more effective than pure compression.

[0031] A further preferred embodiment is that, in its clamped state, the clamping body rests with its triangular section surface against the free end of the dip tube and / or against a support ring at the free end of the dip tube, and with its triangular base surface at least partially against the inner surface of the end piece. Thus, the triangular leg surfaces that protrude laterally beyond the triangular section surface can bend and fold inward, making the clamping body more elastically flexible.

[0032] Furthermore, it is particularly preferred if the clamping body has a through-opening by means of which it can be pivotally held at the end of the dip tube, preferably on a support ring which is attached to the end of the dip tube, by means of a pin or threaded pin, preferably in the form of a screw. By means of the threaded pin, which is preferably glued in with Loctite or similar after it has been adjusted, the extent to which the clamping body tilts downwards when not yet clamped can be adjusted. The shape of the through-opening is crucial here, as it can create stop points for the pin. Ideally, the shape of the through-opening here is a blend of cylindrical and conical shapes, at least in sections.

[0033] Furthermore, it is particularly preferred if the triangular base surface of the clamping body has a recess – preferably in the shape of a cylindrical segment – ​​in its central region or in the area around the said through-hole. This allows the end fitting to be gripped more easily and thus ensures a more ideal fit. This also initiates the clamping body's rotation after it has been inserted into the radial gap between the free end of the dip tube and the end fitting.

[0034] Furthermore, it is particularly preferred if the clamping body is held in a groove of a support ring that clamps the free end of the dip tube in the axial direction, preferably with some lateral play, so that the clamping body can not only pivot up and down relative to the final installation position, but can also adjust itself somewhat clockwise and counterclockwise. This allows for compensation for further manufacturing tolerances and / or general inaccuracies.

[0035] A further preferred embodiment consists in providing at least three clamping bodies, preferably arranged substantially evenly along the circumference of the dip tube or its support ring. This allows the annular gap to be bridged evenly over its circumference, preventing the free end of the dip tube from colliding with the end piece on one side. LIST OF FIGURES

[0036] The Fig. 1 shows a tank unit with a cut tank and a tank pump whose immersion tube is inserted into an end nozzle in side view (state of the art). Fig. 2 shows the free end of a dip tube which has been inserted into an end piece, with the free end carrying an O-ring retainer (state of the art). Fig. 3shows the free end of the immersion tube of a tank pump with clamping bodies and the end nozzle in a sectional, three-dimensional view, with the clamping bodies in a clamped position. Fig. 4 shows the free end of the immersion tube of a tank pump with clamping bodies in a three-dimensional view in a relaxed position, not inserted into an end nozzle. Fig. 5 shows the free end of the immersion tube of a tank pump with clamping bodies and the end nozzle in a sectional front view, with the clamping bodies in a pivoted position. Fig. 6 shows the free end of the immersion tube of a tank pump with clamping bodies and the end nozzle in a sectional front view, with the clamping bodies in a clamped position. PREFERRED EMBODIMENT

[0037] First of all, it should be emphasized that the Fig. 1 (as well as the Fig. 2 ) only shows the state of the art or the technical background of the invention, this representation in Fig. 1However, it is also important for the preferred embodiment of the invention. Fig. 1 The tank unit 1 shown also represents an exemplary, preferred embodiment of the tank unit according to the invention, wherein there are changes compared to the prior art, particularly in the area of ​​the free end 15 of the dip tube 5 or in the area of ​​the end nozzle 6.

[0038] However, the preferred embodiment according to the invention has, as in Fig. 1 shown a tank pump 3 as an eccentric screw pump with stator 4, wherein the motor 102 of the tank pump 3 is located outside the tank 2 (see Fig. 1 ). Reference is again made to the explanations in the corresponding section "State of the art" or "Technical background". To simplify the figures and for better understanding, Fig. 3 to 6the upper part of the tank pump 3, the upper part of the immersion tube 5 as well as the tank 2 and thus the entire tank unit according to the invention are not shown, since here a design analogous to that shown in Fig. 1 shown is to be expected.

[0039] First, Fig. 3 the free end 15 of the immersion tube 5 of the tank pump 3 mentioned, which is shown here as an eccentric screw pump with stator 4. The stator 4 preferably extends at least to the free end 15 of the immersion tube 5. The stator 4 has a stator housing 21 which essentially completely encloses the stator. The stator housing 21 is preferably completely and at least partially enclosed by the immersion tube 5, as shown in the Fig. 3 , Fig. 5 and Fig. 6 shown.

[0040] At the free end 15 of the immersion tube 5, a support ring 17 is attached, which accommodates additional support struts 20 (see Fig. 4). In addition, several grooves are provided in this support ring 17, in which clamping bodies 7 are mounted. These clamping bodies 7 are preferably designed in the form of a prism 10, wherein the cross section of the prism 10 forms a triangular section cross section 11.

[0041] The prism 10 or the clamping body 7 thus formed has a triangular base surface 12 and a triangular section surface 13 arranged essentially parallel thereto. These two surfaces are connected to each other by triangular leg surfaces 14. The clamping bodies 7 of this type are thus mounted in grooves of the support ring 17, preferably each by means of a screw 16, so that preferably at least three clamping bodies 7 are arranged evenly distributed over the circumference of the support ring 17, which Fig. 4 Here, the cylindrical recess 19 on the triangular base surface 12, which the clamping body 7 preferably has, can also be seen.

[0042] During assembly, the free end 15 of the immersion tube 5 must be inserted into an end fitting 6, as already described several times. In a first step of insertion, the wedge section 8 of the clamping body 7 helps with "threading" into the end fitting 6. Due to the specially shaped through-opening 18 of the clamping body, the clamping body 7 is able to rotate or pivot, which in Fig. 5 is shown.

[0043] The free end 15 of the immersion tube 5 is then pushed further into the end piece 6, whereby the clamping body pivots again so that its triangular section surface 13 rests on the support ring 17 and its triangular base surface 12 rests on the end piece 6, and the clamping body 7 itself is also under tension and elastically deformed. Thus, the radial gap 9 between the immersion tube 5 or its support ring 17 and the end piece 6 is compensated, and the immersion tube 5 is clamped in the end piece 6. This state is both in Fig. 3as well as in Fig. 6 shown.

[0044] The through-opening 18 is generally preferably designed such that it is not rotationally symmetrical to the center axis of the clamping body 7. Thus, the through-opening 18 is designed in its lower half at least partially as a cylindrical cutout and in its upper half at least partially as a conical cutout. Thus, the head of the screw 16 preferably partially rests on the cylindrical cutout in the clamped position of the clamping body 7 (see Fig. 6 ) and in the pivoted position of the clamping body 7 at least partially on the conical cutout (see Fig. 5 ). LIST OF REFERENCE SYMBOLS

[0045] 1Tank unit 2Tank 3Tank pump 4Stator of the eccentric screw pump 5Immersion tube 6End connection 7Clamping body 8Wedge section 9Radial gap 10Prism 11Triangular section cross-section 12Triangular base surface 13Triangular section surface 14Triangular leg surfaces 15Free end of the immersion tube 16Screw 17Support ring at the free end of the immersion tube 18Through-hole of the clamping body 19Cylindrical section-shaped recess 20Support strut 21Stator housing 101O-ring holder 102Tank pump motor 103O-ring

Claims

1. A tank unit (1) of at least one tank (2) and a tank pump (3) submerged in the tank (2) or immersed in the tank (2) with an immersion tube (5), which preferably extends all the way down to the lowest removal point of the tank (2), wherein an end fitting (6) is fastened on the lowest removal point of the tank (2), into which end fitting the immersion tube (5) is at least partly inserted, wherein at least one or several clamping bodies (7) are provided in the region of the free end (15) of the immersion tube (5), preferably on a support ring (17) on the free end (15) of the immersion tube (5), characterized in that in its relaxed position, the at least one clamping body (7) has at least one wedge section (8), which penetrates into the radial gap (9) between the end fitting (6) and the free end (15) of the immersion tube (5) in the course of the insertion of the free end (15) of the immersion tube (5) into the end fitting (6), and that the at least one clamping body (7) has an axis of rotation, which is perpendicular to the insertion direction, whereby the clamping body (7) rotates in the course of the complete insertion of the free end (15) of the immersion tube (5) into the end fitting (6) and thus braces the free end (15) of the immersion tube (5) in the end fitting (6).

2. The tank unit (1) according to claim 1, characterized in that the clamping body (7) is elastic in such a way that it can compensate tolerance- or contamination-related dimensional deviations of the radial gap (9) between the free end (15) of the immersion tube (5) and the end fitting (6) by means of its own, preferably elastic deformation.

3. The tank unit (1) according to claim 1 or 2, characterized in that the at least one clamping body (7) is designed as prism (10), preferably as four-sided prism (10) with triangular section cross section (11) with an extension perpendicular to the plane of the triangular section cross section (11) > 1 mm, better > 5 mm, with a triangular base surface (12), a triangular section surface (13), which is preferably parallel to the base surface (12), and two triangular leg surfaces (14), which converge from the triangular base surface (12) in the direction towards the triangular section surface (13).

4. The tank unit (1) according to one of the preceding claims, characterized in that in its braced state, the clamping body (7) rests with its triangular section surface (13) against the free end (15) of the immersion tube (5) and / or against a support ring (17) on the free end (15) of the immersion tube (5) and rests with its triangular base surface (12) against the inner surface of the end fitting (6).

5. The tank unit (1) according to one of the preceding claims, characterized in that the clamping body (7) has a passage opening (18), by means of which it can be pivotably held on the free end (15) of the immersion tube (5), preferably on a support ring (17), which is attached to the free end (15) of the immersion tube (5), by means of a pin, preferably in the form of a screw (16).

6. The tank unit (1) according to one of the preceding claims, characterized in that the triangular base surface (12) of the clamping body (7) has in its middle region or in its region around said passage opening (18), respectively, a recess (19), preferably in the form of a segment of a circle.

7. The tank unit (1) according to one of the preceding claims, characterized in that the clamping body (7) is designed and dimensioned so that a toggle lever effect occurs on it in such a way that the clamping body (7) moves on its own from its still pivoted position into its completely braced position when exceeding a certain pivot angle.

8. The tank unit (1) according to one of the preceding claims, characterized in that the clamping body (7) is held in a groove of a support ring (17), which braces the free end (15) of the immersion tube (5) in the axial direction, preferably with a slight lateral play, so that the clamping body (7) cannot only pivot upwards and downwards but can also align clockwise and counterclockwise to some extent.

9. The tank unit (1) according to one of the preceding claims, characterized in that the clamping body (7) pivots, in that it tilts on its triangular section surface (13) over an edge on the free end (15) of the immersion tube (5) or over an edge of the support ring (17) attached to the free end (15) of the immersion tube (5), respectively.

10. The tank unit (1) according to one of the preceding claims, characterized in that at least three clamping bodies (7) are provided, which are preferably arranged so as to be distributed evenly along the circumference of the immersion tube (5) or the support ring (17) thereof.

11. The tank unit (1) according to one of the preceding claims, characterized in that the tank pump (3) is an eccentric screw pump (4).

12. A tank pump (3) with an immersion tube (5), which can be guided down all the way to the lowest removal point of a tank (2), where an end fitting (6) is fastened, into which the immersion tube (5) can be at least partly inserted, wherein at least one or several clamping bodies (7) are provided in the region of the free end (15) of the immersion tube (5), preferably on a support ring (17) on the free end (15) of the immersion tube (5), characterized in that in its relaxed position, the at least one clamping body (7) has a wedge section (8), which can penetrates into the radial gap (9) between the end fitting (6) and the free end (15) of the immersion tube (5) in the course of the insertion of the free end (15) of the immersion tube (5) into the end fitting (6), and that the at least one clamping body (7) has an axis of rotation, which is perpendicular to the insertion direction, whereby the clamping body (7) can rotate into the correct end fitting (6) in the course of the complete insertion of the free end (15) of the immersion tube (5) and thus braces the free end (15) of the immersion tube (5) in the end fitting (6).

13. The tank pump (3) according to claim 12 with one or several features from claims 2 to 11, which relate to the tank pump (3) and / or the clamping body (7).

14. A method for fixing the free end (15) of an immersion tube (5) of a tank pump (3) in an end fitting (6) of a tank (2), which, as a rule, is protected against the direct access by the installer during the installation, characterized in that one or several movable clamping bodies (7) are used, which have an axis of rotation, which is perpendicular to the insertion direction, whereby the clamping body or the clamping bodies (7) initially penetrate into the radial gap (9) between the free end (15) of the immersion tube (5) and the end fitting (6) by means of wedge sections (8) in the course of the insertion of the free end (15) of the immersion tube (5) into the end fitting (6) and thus center or pre-center the immersion tube (5) and the end fitting (6) relative to one another and are then pivoted by means of pushing the free end (15) of the immersion tube (5) into the end fitting (6) and thus finally brace the free end (15) of the immersion tube (5) and the end fitting (6) together, so that a tank unit (1) according to claim 1 and / or a tank pump (3) according to claim 12 is preferably realized.