Clamping device for X-ray tube

Abstract

Device for generating X-rays (X-ray tube) (40) comprising at least one cathode chamber (chamber) (41), a filament holder (42) with a filament (43) attached to its front face (42a), wherein the filament holder (42a) is connected to a high-voltage generator (44) by a high-voltage cable or originates directly from a high-voltage generator (44), a fastening device (45) for connecting the filament holder (42) or the generator (44) having a filament holder to the chamber (41), preferably designed for a vacuum-tight connection, wherein the front face (42a) of the filament holder (42) projects into the interior of the cathode chamber (41) in the connected state, characterized in that the fastening device (45) comprises a clamping and locking device (45) which has at least a quick-release clamping device (45a) and / or at least one clamping device (45a).which is accessible from the side facing away from the chamber (rear side) (44a) of the filament holder (42) or of the generator (44) having the filament holder (42).

Description

[0001] The subject of an independent invention is a device for generating X-rays, in particular a device for opening and closing the X-ray tube in order to replace a filament.

[0002] Known X-ray tubes can be distinguished as those with a transmission target (transmission tube) and those with a reflection target (reflection tube). Furthermore, the generator providing the high voltage and / or the vacuum pump required for evacuating the tube (vacuum chamber, also referred to here as cathode chamber) can be located outside the housing containing the X-ray tube (equipment chamber such as an X-ray protective hood) or inside it. In DE202017104053, the applicant describes an X-ray tube by way of example in which the generator is directly flanged to the vacuum chamber, allowing the filament holder to be located in the vacuum chamber without the otherwise necessary high-voltage cable from the generator to the filament, and the vacuum pump is also located close to the tube and thus inside the X-ray protective hood.In conventional X-ray tubes, the generator and vacuum pump are located away from the vacuum chamber and connected by correspondingly long cables or hoses.

[0003] A disadvantage of both designs is that replacing a worn filament requires its laborious removal from its operating position within the vacuum chamber, necessitating the opening of the tube. The filament extends from a filament holder, which is typically fixed at the end furthest from the filament to a receptacle, such as the generator. Filament holders with filament must therefore be pulled out of the vacuum tube in a specific direction, often requiring the also time-consuming removal of cables and hoses. When reinserting the holder, sealing surfaces between the vacuum chamber and the filament holder must be ensured so that the vacuum tube can be evacuated after the new filament is inserted. For secure attachment between the filament holder and the vacuum tube, plates are usually provided, fastened with several screws, and the seal is positioned between them.In the area of ​​these fastenings (screws), there is usually very little space to operate the fastening screws with tools. This makes simple maintenance (filament replacement) impossible. Furthermore, due to the difficult accessibility, there is a risk that the alignment of the sealing surfaces and the tightening with the correct torque cannot be performed consistently enough using tools. This can result in the filament not being positioned correctly, the vacuum tube not being sealed airtight (if the tightening torque is too low), or the screws being damaged (if the tightening torque is too high).

[0004] Another disadvantage is that steps such as venting and evacuating the vacuum tube are usually only possible manually and are complicated to perform using the X-ray tube manufacturer's software. Other steps, such as switching on the high voltage or starting a measurement with the computed tomography scanner containing the X-ray tube, can be performed using the software of the computed tomography scanner manufacturer.

[0005] Overall, this makes filament replacement very complex, prone to errors, and only possible with suitable tools and appropriately trained personnel, thus making it expensive. Consequently, this leads to long interruptions in the measurements, which are to be carried out using a computed tomography scanner equipped with an X-ray tube.

[0006] One object of the present invention is therefore to simplify filament replacement in an X-ray tube in order to achieve shorter maintenance times and a more cost-effective procedure. In particular, the aim is to enable the safe, tool-free opening and closing of the vacuum tube. Furthermore, work steps are to be at least partially automated. The filament replacement should also be possible for an operator with less training than a service technician.

[0007] The invention provides a solution by including a fastening device for connecting the vacuum tube to the filament holder or the generator that has the filament holder. This device comprises a clamping and locking mechanism, which is designed to be easily operated as a quick-release clamping device, preferably a tool-free quick-release clamping device, and / or is a clamping device with easily accessible mounting points on the outside (the side of the generator facing away from the cathode chamber). To avoid having to disconnect cables and hoses, appropriately long cable loops are provided. In addition, a movable carriage is provided for receiving and moving the generator away from and towards the cathode chamber.

[0008] An inventive device for generating X-rays (X-ray tube) comprises at least one cathode chamber (chamber), a filament holder with a filament attached to its front face, wherein the filament holder is connected to a high-voltage generator (generator) by a high-voltage cable or originates directly from a high-voltage generator, a fastening device for connecting the filament holder or generator having a filament holder to the chamber, preferably designed for a vacuum-tight connection, wherein the front face of the filament holder projects into the interior of the cathode chamber when connected, and is characterized in that the fastening device comprises a clamping and locking device, which has at least a quick-release clamping device and / or at least one clamping device.which is accessible from the side facing away from the chamber (rear side) of the filament holder or of the generator containing the filament holder.

[0009] In particular, the invention is characterized in that the clamping and locking device is designed to exert a pulling force that presses the filament holder or the generator and vacuum chamber having the filament holder together.

[0010] Preferably, the X-ray tube is designed as a transmission tube, i.e., it has a transmission target.

[0011] In principle, the solution according to the invention can also be applied to reflection tubes. The following descriptions refer to transmission tubes, but can be applied analogously to reflection tubes as well.

[0012] It should also be emphasized that the filament intake originates directly from the generator and that the unit consisting of both can be connected to the chamber, preferably flanged to it, and particularly preferably vacuum-tightly connected by means of a vacuum seal, and particularly preferably that the vacuum pump is directly connected to the chamber.

[0013] The invention is also characterized in that the clamping device comprises a tool-free quick-release clamping device with which a defined tightening force is achieved in the tightened state, wherein the tightening force is preferably pre-adjustable, preferably the quick-release clamping device has clamping hooks, particularly preferably three clamping hooks, which are preferably arranged symmetrically to the contact surface between the chamber and the filament holder or generator.

[0014] According to a particularly noteworthy proposal, the clamping hooks are attached to the chamber or to an adapter plate connected to the chamber by means of bolts, so that the clamping hooks are arranged offset towards the rear of the filament holder or generator, preferably behind the rear of the filament holder or generator.

[0015] As an alternative to bolts, other connecting elements such as hollow tubes, bars, or flat connectors are also provided. The connectors are preferably designed with a small cross-section to minimize the space required laterally to the main direction.

[0016] It is particularly noteworthy that at least one clamping plate is arranged on the back of the filament holder or generator, into which the clamping hooks engage and, when tightened, generate the clamping force between the filament holder or generator and the chamber.

[0017] The clamping hooks press against the back of the clamping plate, thus reaching past it laterally or through suitable openings in it.

[0018] Furthermore, the invention is characterized in that the clamping plate is connected by bolts to the filament holder or the front of the generator or to an adapter plate extending from the filament holder or the front of the generator.

[0019] The bolts create a connection from the back to the front, so that by pulling on the easily accessible clamping plate at the back, the filament holder or generator can be easily moved away from the chamber.

[0020] In particular, the invention is also characterized by the fact that cables emanating from the generator, such as cables for cooling and control, are designed in such a length, preferably as cable loops, that the generator can be moved away from the chamber at least far enough to allow the filament to exit the chamber without disconnecting the cables.

[0021] Preferably, the invention provides that a slide designed to receive the generator can be moved up to the generator from below, and that the slide has a direction of movement that runs parallel to the connection between the front and back of the generator.

[0022] The slide allows the generator to be moved far enough back, into a service position, so that the filament can be removed from the chamber and replaced.

[0023] It should also be emphasized that the X-ray tube is arranged in an equipment chamber such as an X-ray protective hood together with at least one X-ray detector and a rotary table for receiving a workpiece to be examined, and is thus part of a computed tomography scanner for examining workpieces, wherein the equipment chamber preferably has a maintenance access such as a door, which is designed as an access for filament receiving.

[0024] Preferably, the generator and / or the vacuum pump is also arranged in the equipment chamber to form a compact unit.

[0025] Further details, advantages and features of the invention will become apparent not only from the claims and the features to be derived therefrom - individually and / or in combination - but also from the following description of the figure.

[0026] It shows: Fig. 1 An exemplary embodiment of the X-ray tube according to the invention with a generator arranged directly on the vacuum chamber.

[0027] Based on the Fig.Figure 1 illustrates the invention by way of example. The X-ray tube 40 comprises a plurality of individual components, of which only those relevant to the invention are shown here in excerpts and schematically. The cathode chamber (vacuum chamber) 41 is shown here by way of example in a construction in which the high-voltage generator 44 is directly connected to it via vacuum sealing surfaces 46. The filament holder 42 extends directly from the generator 44 and, in the connected state, its front end 42a extends into the interior of the vacuum chamber 41. The filament 43 is interchangeably arranged at the front end 42a. When the high voltage is switched on and the vacuum chamber 41 is evacuated by means of a vacuum pump 47, electrons 43a are emitted from the filament 43 and are directed, and usually also focused, onto the target 49 of the X-ray tube by means of deflection mechanisms not shown here.The design shown here is a transmission tube, i.e., with transmission target 49, so that on the opposite side of the point of impact of the electrons on the target 49 the X-ray radiation 50 is emitted, for example to carry out a computed tomography of a workpiece not shown here with a computed tomography scanner, which for this purpose has at least one X-ray detector and a rotary table for rotating the workpiece.

[0028] According to the prior art, the filament holder 42 or the generator 44 is attached to the chamber 41 by means of several screws on the side of the filament holder 42 or the generator 44 facing the chamber 41, and is therefore difficult to access and only accessible with tools. In contrast, the invention provides a clamping and locking device 45 which has a quick-release clamping device 45c, which, in a preferred design, is also accessible from the side (rear side) 44a of the filament holder 42 or the generator 44 facing away from the chamber 41.

[0029] The clamping and locking device 45 exerts a tightening force that presses the filament holder 42 or the generator 44 and the vacuum chamber 41 towards each other when the clamping hooks 45c are closed (the solid line represents the closed state, and the dashed line represents the open state of the clamping hooks). For easy access to the clamping hooks 45c, these are connected to the chamber 41 via the bolts 45b and the adapter plate 45a and are arranged on the side 44a of the filament holder 42 or the generator 44 facing away from the chamber 41 (rear side). Preferably, three of these arrangements are distributed symmetrically such that the tightening force acts in a direction perpendicular to the sealing surfaces 46 in order to avoid tilting moments and achieve maximum sealing effectiveness.The clamping hooks 45c press against the rear side of a clamping plate 45d connected to the filament holder 42 or, as in the illustrated example, to the generator 44, by engaging through suitable openings in the clamping plate. This also allows the clamping plate 45d, together with the generator 44, to be moved away (to the right in the figure) when open. The clamping plate 45d is connected to the front of the generator 44 via the bolts 45e and the adapter plate 45f. This design is not mandatory, but it provides improved stability and allows existing screw points on the generator 44 to be used, if applicable. Furthermore, it allows the generator 44 to be easily pulled backward (to the right in the figure).

[0030] The invention provides for the use of the carriage 48 to move the generator 44 together with the filament holder 42 from the position connected to the chamber 41 to the service position (to the right in the figure), in which the filament 43 has exited the chamber 41 and is thus accessible for replacement. The carriage 48 can be moved from below towards the generator 44 by means of the drive 48b so that, after the clamping hooks 45c are released, the generator 44 rests on the carriage 48. Before the clamping hooks 45c are released, the chamber 41 is vented by the valve 41a. The drive 48a moves the carriage 48 with the generator 44 and the filament holder 42 backward (to the right in the figure) into the service position. After the filament 43 has been replaced, the carriage 48 is used to move the generator 44 back towards the chamber 41. The clamping hooks 45c are then closed again and the chamber 41 is evacuated using the vacuum pump 47.This is connected to chamber 41 via connecting hoses 47a. Valve 41a serves to ventilate the chamber. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 202017104053

[0002]

Claims

[1] Device for generating X-rays (X-ray tube) (40) comprising at least one cathode chamber (chamber) (41), a filament holder (42) with a filament (43) attached to its front (42a), wherein the filament holder (42a) is connected to a high-voltage generator (44) by a high-voltage cable or extends directly from a high-voltage generator (44), a fastening device (45) for connecting the filament holder (42) or the generator (44) having a filament holder to the chamber (41), preferably designed for a vacuum-tight connection, wherein the front (42a) of the filament holder (42) projects into the interior of the cathode chamber (41) when connected, characterized by, that the fastening device (45) comprises a clamping and locking device (45) which has at least a quick-release clamping device (45a) and / or at least a clamping device (45a) which is accessible from the side (rear) (44a) of the filament holder (42) or of the generator (44) having the filament holder (42) facing away from the chamber. [2] Device according to claim 1, characterized by , that the clamping and locking device (45) is designed to exert a tightening force that presses the filament holder (42) or the generator (44) and vacuum chamber (41) having the filament holder (42) together. [3] Device according to claim 1 or 2, characterized by , that the X-ray tube (40) is designed as a transmission tube, i.e., it has a transmission target (49). [4] Device according to at least one of the preceding claims 1 to 3, characterized bythat the filament holder (42) extends directly from the generator (44) and the unit consisting of both can be connected to the chamber (41), preferably flanged to it, particularly preferably vacuum-tightly connected by means of a vacuum seal (46), particularly preferably a vacuum pump (47) is directly connected to the chamber. [5] Device according to at least one of the preceding claims 1 to 4, characterized by , that clamping device (45) comprises a tool-free operable quick-clamping device (45a) with which a defined tightening force is achieved in the tightened state, wherein the tightening force is preferably pre-adjustable, preferably quick-clamping device has clamping hooks (45c), particularly preferably three clamping hooks (45c) which are preferably arranged symmetrically to the support surface (46) between chamber (41) and filament holder (42) or generator (44). [6] Device according to at least one of the preceding claims 1 to 5, characterized by that the clamping hooks (45c) are attached to the chamber (41) or to an adapter plate (45a) connected to the chamber (41) by bolts (45b), so that the clamping hooks (45c) are arranged offset towards the rear (44a) of the filament holder or generator, preferably behind the rear (44a) of the filament holder or generator. [7] Device according to at least one of the preceding claims 1 to 6, characterized by , that at least one clamping plate (45d) is arranged on the rear (44a) of the filament holder (42) or generator (44), into which the clamping hooks (45c) engage and, when tightened, generate the tightening force between the filament holder (42) or generator (44) and the chamber (41). [8] Device according to at least one of the preceding claims 1 to 7, characterized by, that the clamping plate (45d) is connected by bolts (45e) to the filament holder (42) or the front of the generator (44) or to an adapter plate (45f) extending from the filament holder (42) or the front of the generator (44). [9] Device according to at least one of the preceding claims 1 to 8, characterized by , that cables extending from the generator (44), such as cables for cooling and control, are designed in such a length, preferably as cable loops, that the generator (44) can be moved away from the chamber (41) at least as far as the filament (43) can exit the chamber (41) without disconnecting the cables. [10] Device according to at least one of the preceding claims 1 to 9, characterized by, that a slide (48) designed to receive the generator (44) can be moved up to the generator (44) from below, and that the slide (48) has a direction of movement (48a) which runs parallel to the connection of the front and back (44a) of the generator (44). [11] Device according to at least one of the preceding claims 1 to 10, characterized by , that the X-ray tube (40) is arranged in an equipment chamber such as an X-ray protective hood together with at least one X-ray detector and a rotary table for receiving a workpiece to be examined and is thus part of a computed tomography scanner for examining workpieces, wherein the equipment chamber preferably has a maintenance access such as a door, which is designed as an access to the filament receiving (42).

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