Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a point scanning device with a disc-type chopper wheel.
In order to achieve the purpose, the invention adopts the following technical scheme:
a point scanning device with a disc-type chopper wheel comprises a disc-type chopper wheel, an X-ray source part and a fan-shaped collimator; the disc type chopping wheel comprises a hub, a positioning wheel disc, a tubular column collimator, positioning mechanisms and a lead shielding ring, wherein the lead shielding ring is fixed on and covers the inner circumferential surface of the hub; the inner part of the tubular column collimator is provided with a tubular column collimation hole extending along the length direction, the inlet end of the tubular column collimation hole is communicated with the inner ring of the hub, and the outlet end of the tubular column collimation hole is communicated with the outside; the sector collimator is fixed with the X-ray source component, and the ray source core of the X-ray source component is positioned on the central axis of the sector collimation hole and is positioned on the same straight line with the central axis of the hub; the fan-shaped collimator is positioned on the inner ring of the hub and used for collimating X-rays generated by the X-ray source component to form fan-shaped ray beams and emitting the fan-shaped ray beams to the inner circumferential surface direction of the hub; the central axis of each pipe column collimation hole is intersected with the ray source core and is positioned on the same plane with the central axis of the fan-shaped collimation hole, the included angle of the central axes of the adjacent pipe column collimation holes is equal and larger than the central angle of the fan-shaped collimation hole, and the inlet end of at most one pipe column collimation hole is positioned in the emergent range of the fan-shaped collimation hole at the same moment; the hub is in transmission connection with the power device and is driven by the power device to rotate.
Furthermore, the disc-type chopped wave wheel also comprises a bearing cantilever frame and a driving shaft part, wherein the driving shaft part is connected with a bearing at the top of the bearing cantilever frame, one end of the driving shaft part is in transmission connection with an output shaft of a driving motor, and the other end of the driving shaft part is in transmission connection with a wheel hub.
Furthermore, one end of the X-ray source component, which is far away from the fan-shaped collimator, is connected with a supporting base, and the bottom surface of the supporting base and the bottom surface of the bearing cantilever frame are located on the same horizontal plane.
Further, the column collimator is made of a high-density material which can effectively shield X-rays and has mechanical structural strength satisfying design requirements.
Further, the cross-sectional shape of the pipe column collimation hole is circular or rectangular.
Furthermore, the wheel hub is made of high-quality structural steel, and the positioning wheel disc is made of high-strength aluminum.
Furthermore, a plurality of dynamic balance weight holes with the same radius are arranged on the positioning wheel disc along the circumferential direction, and the dynamic balance weight holes are arranged at the same angle.
Furthermore, a plurality of dynamic balance auxiliary weight holes with equal radiuses are formed in the hub along the circumferential direction, and the dynamic balance auxiliary weight holes are arranged at equal angles.
Furthermore, a plurality of rows of synchronous signal photoelectric holes are formed in the hub, the number of the rows of synchronous signal photoelectric holes is the same as that of the column collimators, the synchronous signal photoelectric holes are distributed along the circumferential direction, one row of synchronous signal photoelectric hole is formed between every two adjacent column collimators, and the centers of the rows of synchronous signal photoelectric holes are located on an angular bisector of an included angle of central axes of the two adjacent column collimator holes; two column synchronous signal control plates are respectively arranged on two sides of the column synchronous signal photoelectric hole along the central axis direction, wherein one column synchronous signal control plate is provided with a photoelectric transmitting end, and the other column synchronous signal control plate is provided with a photoelectric receiving end; the boundaries of two sides of the fan-shaped collimation hole are a screwing-in boundary and a screwing-out boundary in sequence along the rotation direction of the hub, and when the inlet end of the tubular column collimation hole rotates to reach the screwing-in boundary of the fan-shaped collimation hole, a row of synchronous signal photoelectric holes are just corresponding to the photoelectric transmitting end and the photoelectric receiving end respectively.
Furthermore, a wheel synchronization signal photoelectric hole is arranged right above or below one column synchronization signal photoelectric hole; two photoelectric transmitting ends are arranged on one column synchronous signal control board, two photoelectric receiving ends are arranged on the other column synchronous signal control board, and the two photoelectric transmitting ends and the two photoelectric receiving ends are respectively positioned on a vertical straight line; when the column synchronous signal photoelectric holes of the wheel synchronous signal photoelectric holes are rotated to correspond to the two column synchronous signal control plates, the column synchronous signal photoelectric holes just correspond to one photoelectric transmitting end and one photoelectric receiving end, and the wheel synchronous signal photoelectric holes just correspond to the other photoelectric transmitting end and the other photoelectric receiving end.
The invention has the beneficial effects that:
1) according to the invention, the chopping wheel component adopts a novel disc type structure, and the design of the wheel disc, the wheel hub and the tubular column collimator is beneficial to optimizing the size of the chopping wheel, simplifying the structure of the chopping wheel, reducing the rotation inertia of the chopping wheel and improving the rotation speed of the chopping wheel, so that the resolution of a detected image is improved, and the high-speed, small-sized, light-weight and economical chopping wheel is realized.
2) The invention realizes the setting of the tubular column collimator by adopting the positioning wheel disc and the positioning mechanism, ensures the reliable connection and the accurate positioning of the tubular column collimator, ensures the scanning of the pen-shaped ray beam to be more accurate and improves the quality of the detected image.
3) The invention adopts high-density materials such as tungsten-iron-nickel alloy and the like which can shield X-rays and have certain mechanical structure strength to manufacture the tubular column collimator, ensures the equal sections of collimated pencil-shaped ray beams, concentrates the energy of the ray beams in a high-energy area, and improves the penetrating power of ray detection.
4) In the invention, the chopper wheel generates synchronous photoelectric signals to control the signal acquisition of the detector, and simultaneously controls the chopper wheel to drive the motor to limit and brake, so that after the chopper wheel brakes, the tubular column collimator is not in the range of the fan-shaped collimating hole, and the radiation leakage during non-detection work is prevented.
Detailed Description
The present invention will be further described with reference to the accompanying drawings, and it should be noted that the present embodiment is based on the technical solution, and the detailed implementation and the specific operation process are provided, but the protection scope of the present invention is not limited to the present embodiment.
The embodiment provides a point scanning device with a disk chopper wheel, as shown in fig. 1-4, comprising a disk chopper wheel, an X-ray source component 4 and a sector collimator 3; the disc type chopping wheel comprises a hub 11, a positioning wheel disc 12, a tubular column collimator 13, a positioning mechanism 14 and a lead shielding ring 15, wherein the lead shielding ring 15 is fixed on and covers the inner circumferential surface of the hub 11, the positioning wheel disc 12 is fixed on the outer circumferential surface of the hub 11 and is coaxial with the hub 11, the positioning wheel disc 12 is provided with a plurality of positioning mechanisms 14 and tubular column collimators 13, one end of the tubular column collimator 13 penetrates through and is fixedly connected with the hub 11 and the lead shielding ring 15, and the other end of the tubular column collimator 13 is connected with the positioning mechanisms 14; the interior of the column collimator 13 is provided with a column collimating hole 131 extending along the length direction, the inlet end of the column collimating hole 131 is communicated with the inner ring of the hub 11, and the outlet end of the column collimating hole 131 is communicated with the exterior; the sector collimator 3 and the X-ray source component 4 are fixed, and a ray source core 401 of the X-ray source component 4 is located on a central axis of a sector collimation hole of the sector collimation hole and is located on the same straight line with the central axis of the hub 11; the fan-shaped collimator 3 is positioned at the inner ring of the hub 11 and is used for collimating the X-rays generated by the X-ray source component 4 to form fan-shaped ray beams and emitting the fan-shaped ray beams to the inner circumferential surface direction of the hub 11; the central axis of each column collimation hole 131 intersects with the ray source core 401 and is positioned on the same plane with the central axis of the fan-shaped collimation hole, the included angle of the central axes of the adjacent column collimation holes 131 is equal and larger than the central angle of the fan-shaped collimation hole, and the inlet end of at most one column collimation hole 131 is positioned in the emergent range of the fan-shaped collimation hole at the same time; the hub 11 is drivingly connected to and driven to rotate by the power unit.
In the spot scanning device, the X-rays of the X-ray unit 4 are emitted from the source core 401, collimated into fan-shaped beams by the fan-shaped collimating holes in the fan collimator 3, and emitted in the direction of the inner peripheral surface of the hub 11. In the process that the hub 11 rotates around the fan-shaped collimator 3 at a high speed, when reaching the inlet end of the non-pipe column collimation hole on the inner circumferential surface of the hub 11, the fan-shaped ray beam is shielded by the lead shielding ring 15 and cannot be emitted to the outside of the hub, and when reaching the inlet end of the pipe column collimation hole, the fan-shaped ray beam enters the pipe column collimation hole from the inlet end of the pipe column collimation hole and is collimated into a pen-shaped ray beam and then is emitted from the outlet end to irradiate the detected object. After the scanning is stopped, the hub 11 stops rotating, and it is necessary to ensure that all the column collimation holes 131 are not in the emergence range of the fan-shaped collimation holes after the hub 11 is completely stationary, so as to prevent ray leakage during non-detection operation.
The included angle of the central axes of the adjacent pipe column collimating holes 131 is larger than the central angle of the fan-shaped collimating holes, and in the rotating process of the hub 11, at most one pipe column collimating hole 131 is in the emitting range of the fan-shaped collimating holes at the same time, so that only one beam of rays is emitted from the disc-type chopper wheel all the time. With the high-speed rotation of the hub 11, the column collimator 13 rotates together within the range of the fan-shaped collimating aperture, so that the rays are collimated into a pencil-shaped beam through the column collimating aperture 131 and irradiate on the object to be detected, thereby completing a column of scanning from top to bottom of the object to be detected.
In this embodiment, the column collimator 13 includes four column collimating holes 131, the included angle between the central axes of the adjacent column collimating holes is 90 °, and the central angle of the fan-shaped collimating hole of the fan-shaped collimator 3 is 86 °.
Specifically, the inlet end of the collimating hole of the column collimator 13 is screwed with the boss 11 and the lead shield ring 15.
Specifically, in this embodiment, the disc chopper wheel further includes a bearing cantilever frame 7 and a driving shaft member 6, the driving shaft member 6 is connected to a bearing at the top of the bearing cantilever frame 7, one end of the driving shaft member is in transmission connection with the output shaft of the driving motor 1, and the other end of the driving shaft member is in transmission connection with the hub 11. The disc-type chopping impeller is supported by the bearing cantilever frame 7, so that the design and use conditions of a high-speed and high-precision bearing can be met, the chopping impeller can finally rotate at high speed accurately, stably and reliably, high-speed scanning is realized, and the image resolution is improved. The rotation speed of the drive motor 1 can be set according to the scanning speed.
Further, in this embodiment, one end of the X-ray source component 4 away from the sector collimator 13 is connected to the supporting base 2, and a bottom surface of the supporting base 2 and a bottom surface of the bearing cantilever 7 are located on the same horizontal plane, so as to facilitate positioning and installation of the apparatus.
Further, the column collimator 13 is made of a high-density material, such as inconel, which can effectively shield X-rays and has mechanical structural strength satisfying design requirements. The cross-sectional shape of the column alignment hole 131 may be circular or rectangular.
Furthermore, the hub 11 is made of high-quality structural steel, and the positioning wheel disc 12 is made of high-strength aluminum, so that the weight and the moment of inertia of the chopper wheel are further reduced, and the lightweight design is realized.
Furthermore, a plurality of dynamic balance weight holes 121 with equal radius are arranged on the positioning wheel disc 12 along the circumferential direction, and the dynamic balance weight holes 121 are arranged at equal angles. The dynamic balance weight hole 121 is used for dynamic balance correction of the disc type chopping wheel component. In this embodiment, the number of the dynamic balance weight ports 121 is 8, and one dynamic balance weight port is provided every 45 °.
Furthermore, a plurality of dynamic balance auxiliary weight holes 111 with equal radius are arranged on the hub 11 along the circumferential direction, and the dynamic balance auxiliary weight holes 111 are arranged at equal angles. The dynamic balance auxiliary weight hole 111 is used for further assisting the dynamic balance correction of the disc chopper wheel component.
It should be noted that, the disc chopper wheel inevitably generates deviation due to processing, assembly and other reasons, a dynamic balance tester can be used to detect the unbalanced mass and position of the disc chopper wheel, and a counterweight method is used to fix a corresponding counterweight on the dynamic balance counterweight hole 121 or the dynamic balance auxiliary counterweight hole 111 at the corresponding position, so as to complete dynamic balance correction.
Further, a plurality of column synchronization signal photoelectric holes 112 are arranged on the hub 11, the number of the column synchronization signal photoelectric holes 112 is the same as that of the column collimators 13, the column synchronization signal photoelectric holes are distributed along the circumferential direction, one column synchronization signal photoelectric hole 112 is arranged between every two adjacent column collimators 13, and the centers of the column synchronization signal photoelectric holes 112 are located on an angular bisector of an included angle between central axes of the two adjacent column collimation holes 131; two column synchronous signal control plates 5 are respectively arranged on two sides of the column synchronous signal photoelectric hole 112 along the central axis direction, wherein one column synchronous signal control plate 5 is provided with a photoelectric transmitting end, and the other column synchronous signal control plate 5 is provided with a photoelectric receiving end; the boundaries of the two sides of the fan-shaped collimating hole 131 are a screwing-in boundary and a screwing-out boundary in turn along the rotation direction of the hub, and when the inlet end of the tubular column collimating hole 131 rotates to reach the screwing-in boundary of the fan-shaped collimating hole, a row of synchronous signal photoelectric holes 112 are exactly corresponding to the photoelectric transmitting end and the photoelectric receiving end respectively.
In the present embodiment, 4 column synchronization signal photoelectric holes 112 are provided on the hub 11 at 4 × 90 ° intervals, respectively, corresponding to 4 column collimators 13.
It should be noted that the two column synchronization signal control boards are independently and fixedly arranged and do not rotate along with the hub. In the rotating process of the hub, the column synchronization signal control board provided with the photoelectric transmitting end continuously generates infrared beams, and when the column synchronization signal photoelectric holes correspond to the column synchronization signal photoelectric holes, the infrared beams penetrate through the column synchronization signal photoelectric holes to be received by the column synchronization signal control board provided with the photoelectric receiving end to generate column synchronization signals. The column synchronization signal control board provided with a photoelectric receiving end transmits the column synchronization signal to the signal acquisition system, and the signal acquisition system performs timing synchronization calibration on the detection signal by using the column synchronization signal, so that a computer image is regenerated and displayed as an image. In this embodiment, 4 rows of time-series photoelectric signals are generated for each revolution.
Further, in the present embodiment, a wheel sync signal photoelectric hole 113 is provided directly above or directly below one of the column sync signal photoelectric holes 112; two photoelectric transmitting ends are arranged on one column synchronous signal control plate 5, two photoelectric receiving ends are arranged on the other column synchronous signal control plate 5, and the two photoelectric transmitting ends and the two photoelectric receiving ends are respectively positioned on a vertical straight line; when the column synchronization signal photoelectric hole 112 directly above or below the wheel synchronization signal photoelectric hole 113 rotates to correspond to the two column synchronization signal control boards 5, the column synchronization signal photoelectric hole 112 corresponds to one of the photoelectric emitting end and the photoelectric receiving end, and the wheel synchronization signal photoelectric hole 113 corresponds to the other photoelectric emitting end and the photoelectric receiving end.
When the wheel synchronizing signal photoelectric hole rotates to correspond to the two rows of synchronizing signal control boards, the infrared light beam emitted by the photoelectric emitting end corresponding to the position passes through the wheel synchronizing signal photoelectric hole and is received by the corresponding photoelectric receiving end, so that a wheel synchronizing signal is generated, the corresponding row synchronizing signal control boards transmit the wheel synchronizing signal to the signal acquisition system, the wheel synchronizing signal can be used for detecting the rotating speed of the chopping wheel in real time on one hand, and can be used for dividing and calibrating the generation time sequence of the first row of detection signals on the other hand, and then sequentially generating a second row of detection signals, a third row of detection signals and a fourth row of detection signals, and the braking stop position (the rotating angle of 45 degrees in the embodiment) of the tubular column collimator 13 can be determined by using the wheel synchronizing signal, so that the emission of non-.
It should be noted that, because the image quality and resolution are affected by the size of the scanning spot and the scanning speed, under a certain condition, the smaller the scanning spot diameter and the higher the scanning speed, the higher the resolution of the image and the better the image quality. Therefore, to improve the resolution and image quality of the scanned image, it is necessary to appropriately reduce the scanning spot size and increase the chopper wheel rotation speed.
As shown in fig. 5, D1 represents the outer diameter of the ray emitting area, D2 represents the ray collimating aperture, and when the X-ray emitting point is at the periphery of the center of the D1 circle, the emitted X-ray should be shielded as much as possible to increase the spot size. Wherein, L1, L2 indicate the length of the collimation hole when the radius of the hub 11 is R1, L1 indicates that the column collimator extends out of the hub 11, and L2 indicates that the length of the column collimator is the same as the thickness of the hub 11. L3 represents the alignment bore length for a radius of the hub 11 of R2, R1 is less than R2, and L3 is equal to L2. As can be seen from fig. 6, the exit included angles β 1, β 2, and β 3 of L1, L2, and L3 respectively corresponding to the X-rays are different, where the exit angle β 1 corresponding to L1 is the smallest, and the corresponding light spot is the smallest, so as to satisfy the design requirements of the highest resolution and the smallest single detection dose. When the X-ray emergent point is at a position less than or equal to the diameter D1, the collimated light spot effect of the collimated lengths L1 and L3 is the same, and the collimated light spot effect of the collimated length L2 is relatively worst. In addition, the hub having a radius of R2 has a large structural size, weight, and moment of inertia, and increases the manufacturing difficulty and processing cost. Therefore, the chopping wheel structure is light in weight and small in size by adopting a smaller hub radius and a longer length of the tubular column collimator.
Various corresponding changes and modifications can be made by those skilled in the art based on the above technical solutions and concepts, and all such changes and modifications should be included in the protection scope of the present invention.