Hazardous waste incineration pretreatment device

Abstract

The utility model discloses a hazardous waste incineration pretreatment device, and relates to the technical field of hazardous waste treatment, and the scheme is that the hazardous waste incineration pretreatment device comprises a rack; the fixed outer cylinder is mounted on the rack, and a second discharge port is formed in the bottom end of the fixed outer cylinder; the rotary inner cylinder is coaxially mounted in the fixed outer cylinder, the rotary inner cylinder is provided with a solid-liquid separation area and a discharging adjusting area, and a plurality of first discharging openings are formed in the discharging adjusting area in the circumferential direction; the separation gate plate is mounted in the rotary inner cylinder, can reciprocate in the axial direction of the discharging adjusting area and is used for switching the on-off state between the solid-liquid separation area and the first discharging opening; the crushing assembly is provided with a feeding channel and a discharging channel, and the discharging channel coaxially extends into the rotary inner cylinder; the problem that hazardous waste is blocked can be solved, smooth discharging of the hazardous waste is achieved, and the residual rate is reduced.

Description

Technical Field

[0001] This utility model relates to the field of hazardous waste treatment technology, specifically to a hazardous waste incineration pretreatment device. Background Technology

[0002] Hazardous wastes are complex in composition and diverse in properties, requiring systematic pretreatment using a variety of physical and chemical methods before entering the incinerator. On one hand, physical methods such as crushing, screening, and centrifugal dehydration reduce the particle size of lumpy waste to a suitable range, lowering the moisture content of high-moisture wastes. Simultaneously, the appropriate mixing of wastes with different calorific values ​​ensures that the feed material's form and calorific value meet the equipment's operational requirements, preventing equipment blockage or incomplete combustion due to insufficient heat. On the other hand, chemical methods such as neutralization, oxidation detoxification, and solidification stabilization adjust the pH of acidic and alkaline wastewater, decompose toxic substances, and fix heavy metals, effectively reducing the risk of dioxins, heavy metal vapors, and other pollutants generated and emitted during incineration. Furthermore, crushing significantly increases waste compaction density, reducing landfill settlement risks, extending landfill space lifespan, and increasing the contact area with oxygen by reducing particle size, promoting complete combustion, significantly improving thermal energy utilization, and achieving efficient and environmentally friendly hazardous waste treatment.

[0003] A hazardous waste pretreatment device disclosed in authorization announcement number (CN218609704U) includes a pretreatment box, an inner cylinder with multiple equidistant and annularly distributed water outlets on its outer wall, and a rotating shaft inside the cylinder with pulverizing blades on its outer wall. During treatment, solid waste is added to the cylinder, a hydraulic cylinder is activated to embed a mating block into a groove, and a second drive motor drives a turntable to rotate eccentrically for dewatering. Simultaneously, a first drive motor drives the pulverizing blades to rotate. Switching the mating block to rotate in the opposite direction further enhances the pulverizing effect.

[0004] The structure disclosed in this patent has defects in practical applications, specifically as follows: the closed nested layout of the pretreatment box and the cylinder, coupled with the densely distributed shredder assembly on the outer wall of the rotating shaft inside the cylinder, makes it highly susceptible to material jamming and residue buildup when the treated hazardous waste is discharged due to obstruction by the shredder assembly and eccentric rotation. This necessitates frequent shutdowns for manual cleaning, which not only increases the safety risk of operators coming into contact with hazardous waste but also significantly reduces processing efficiency, seriously affecting the practicality and industrial application of the device. Utility Model Content

[0005] The purpose of this utility model is to provide a hazardous waste incineration pretreatment device, which can address the problems in the prior art where the pretreatment box and cylinder are enclosed and nested, and the obstruction caused by the crushing blade assembly leads to difficulties in hazardous waste discharge and high residue rate. It proposes a solution to reduce the obstruction of hazardous waste, realize the smooth discharge of hazardous waste, and reduce the residue rate.

[0006] This utility model is achieved through the following technical solution:

[0007] A hazardous waste incineration pretreatment device includes: a frame; a fixed outer cylinder mounted on the frame, with a second discharge port at its bottom end; a rotating inner cylinder coaxially mounted inside the fixed outer cylinder, the rotating inner cylinder having a solid-liquid separation zone and a discharge adjustment zone, the discharge adjustment zone having multiple first discharge ports along the circumferential direction; a separating gate installed inside the rotating inner cylinder, the separating gate being capable of reciprocating along the axial direction of the discharge adjustment zone to switch the on / off state between the solid-liquid separation zone and the first discharge ports; and a crushing assembly having a feed channel and a discharge channel, the discharge channel extending coaxially into the interior of the rotating inner cylinder.

[0008] Furthermore, in this utility model, the above also includes an electric push rod, which is installed on the inner wall of the discharge adjustment zone. The output end of the electric push rod is connected to the partition gate, which is used to drive the partition gate to perform reciprocating linear motion along the axial direction of the discharge adjustment zone. The inner wall of the discharge adjustment zone is provided with multiple guide grooves along the circumferential direction, and each guide groove extends along the axial direction of the discharge adjustment zone. Multiple guide sliders are installed on the outer periphery of the partition gate along the circumferential direction, and the multiple guide sliders are respectively engaged in the multiple guide grooves.

[0009] Furthermore, in this utility model, an annular sealing plate is provided along the circumferential direction on the side of the aforementioned dividing gate facing the discharge adjustment area. The annular sealing plate is adapted to the inner diameter of the discharge adjustment area, and the annular sealing plate can seal and cooperate with multiple first discharge ports.

[0010] Furthermore, in this utility model, the outer periphery of the aforementioned annular sealing plate is equipped with multiple unblocking components along the circumferential direction, and the multiple unblocking components can unblock multiple first discharge ports respectively.

[0011] Furthermore, in this utility model, the above-mentioned unblocking component includes a clearing contact, an elastic element, and an assembly channel provided on the surface of the annular sealing plate; one end of the elastic element is connected to the bottom wall of the assembly channel, and the other end of the elastic element is connected to the clearing contact; one end of the clearing contact slides and guides the assembly channel, and the other end of the clearing contact is provided with a guide arc that guides and cooperates with the first discharge port.

[0012] Furthermore, in this utility model, the above also includes a drive assembly, which includes a motor, a driving gear, a driven gear, and a central drive shaft; the motor is installed at one end of the fixed outer cylinder, and the output end of the motor is connected to the driving gear; the central drive shaft is coaxially arranged with the fixed outer cylinder, one end of the central drive shaft is connected to the rotating inner cylinder, and the other end of the central drive shaft is connected to the driven gear, which meshes with the driving gear; the outer wall of the rotating inner cylinder is provided with multiple annular grooves along the axial direction; the inner wall of the fixed outer cylinder is provided with multiple annular bosses along the axial direction, and the multiple annular bosses are respectively engaged in the multiple annular grooves.

[0013] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0014] 1. The rotating inner cylinder in this application adopts a partitioned design. When unloading, the partition gate switches to the conduction state. There are no fixed crushing blades or other interfering parts inside. With the help of guide ribs and rotation drive, the material can be smoothly discharged through the first discharge port and the second discharge port by gravity and centrifugal force. The unloading residue rate is almost zero, avoiding downtime for cleaning due to material blockage, and greatly improving the continuity and efficiency of processing.

[0015] 2. In this application, the elastic unblocking component on the outer periphery of the annular sealing plate can move with the partition gate to automatically clean the adhering material on the inner wall of the first discharge port. Through elastic expansion and contraction and inclined guidance, the blockage is broken and the component self-reset, reducing the frequency of manual intervention and ensuring the long-term smooth flow of the discharge channel.

[0016] 3. The coaxial nested structure of the fixed outer cylinder and the rotating inner cylinder in this application, combined with the sealing function of the partition gate, completely isolates the centrifugal dewatering and unloading processes, preventing the spillage of hazardous waste; at the same time, the external drive component and the waterproof and corrosion-resistant design of the electric push rod reduce the risk of operators coming into contact with hazardous waste during equipment maintenance, significantly improving safety. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a schematic diagram of a hazardous waste incineration pretreatment device;

[0019] Figure 2 A three-dimensional view of the fixed outer cylinder;

[0020] Figure 3 This is a sectional view of the fixed outer cylinder;

[0021] Figure 4 A cross-sectional view of the annular sealing plate connecting the partition gate;

[0022] Figure 5This is a schematic diagram of the engagement between the driving gear and the driven gear.

[0023] The attached diagram shows the markings and corresponding component names:

[0024] 1-Frame, 2-Fixed outer cylinder, 3-Crushing assembly, 4-Feeding channel, 5-Motor, 6-Drive gear, 7-Second discharge port, 8-Rotating inner cylinder, 9-Solid-liquid separation zone, 10-Discharge adjustment zone, 11-Filtration sieve, 12-Annular boss, 13-Annular chute, 14-First discharge port, 15-Divider gate, 16-Guide chute, 17-Guide slider, 18-Electric push rod, 19-Central drive shaft, 20-Annular sealing plate, 21-Assembly channel, 22-Elastic element, 23-Clogging contact, 24-Guide arc, 25-Driven gear, 26-Discharge channel. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0026] Example

[0027] Please refer to Figures 1 to 3 This utility model provides a hazardous waste incineration pretreatment device. Its core structure consists of a frame 1, a fixed outer cylinder 2, a rotating inner cylinder 8, a dividing gate 15, and a crushing assembly 3. The frame 1 serves as a supporting foundation for fixing the outer cylinder 2; a second discharge port 7 is opened at the bottom of the outer cylinder 2 for discharging the treated waste and filtrate. The rotating inner cylinder 8 is coaxially nested inside the outer cylinder 2 and can rotate axially. The rotating inner cylinder 8 is divided into a solid-liquid separation zone 9 and a discharge adjustment zone 10: the solid-liquid separation zone 9 has filtrate sieve holes 11 on its wall and axial guide ribs offset from the sieve holes on its inner wall; the discharge adjustment zone 10 is a sealed structure with multiple first discharge ports 14 evenly distributed around its circumference.

[0028] The dividing gate 15 is installed inside the rotating inner cylinder 8 and can reciprocate along the axial direction of the discharge adjustment zone 10 to achieve switching between two working states: in the dewatering state, the dividing gate 15 moves to a specific position to block the connection between the solid-liquid separation zone 9 and the first discharge port 14, preventing hazardous waste from falling from the first discharge port 14 during centrifugal dewatering; in the unloading state, the dividing gate 15 moves to another position to connect the solid-liquid separation zone 9 with the first discharge port 14 so that hazardous waste can be discharged.

[0029] The crushing assembly 3 is equipped with a feed channel 4 and a discharge channel 26. The discharge channel 26 passes through the fixed outer cylinder 2 and the rotating inner cylinder 8 sequentially and is arranged coaxially with the central axis of the rotating inner cylinder 8. The end of the discharge channel 26 extends to the solid-liquid separation zone 9 of the rotating inner cylinder 8. The connection between the discharge channel 26 and the rotating inner cylinder 8 is mechanically sealed. In use, hazardous waste is fed into the crushing assembly 3 through the feed channel 4, crushed, and falls into the rotating inner cylinder 8 through the discharge channel 26. Subsequently, the partition gate 15 is controlled to block the solid-liquid separation zone 9. Under the action of centrifugal force, the hazardous waste is dehydrated. The liquid enters the gap between the fixed outer cylinder 2 and the rotating inner cylinder 8 through the filtrate sieve 11 and is discharged from the second discharge port 7. After dehydration, the partition gate 15 is adjusted to open the solid-liquid separation zone 9. Under the action of the guide ribs, the hazardous waste moves towards the first discharge port 14. Since the second discharge port 7 is located directly below the first discharge port 14, the waste can fall out smoothly, achieving uninterrupted unloading and reducing residue.

[0030] It should be noted that, for ease of equipment maintenance, both the fixed outer cylinder 2 and the rotating inner cylinder 8 can be equipped with detachable maintenance compartment doors on their side walls. These maintenance compartment doors can be secured with quick-release clamps or bolts, and the joints are fitted with high-temperature resistant sealing strips to ensure a tight seal during normal operation.

[0031] Please refer to Figure 3 In some embodiments of this application, an electric push rod 18 is installed on the inner wall of the discharge adjustment zone 10, and its output end is connected to the partition gate 15. The electric push rod 18 is used to drive the partition gate 15 to perform reciprocating linear motion along the axial direction of the discharge adjustment zone 10. Multiple guide grooves 16 are evenly distributed along the circumferential direction on the inner wall of the discharge adjustment zone 10, and each guide groove 16 extends along the axial direction of the discharge adjustment zone 10. Multiple guide sliders 17 are correspondingly installed on the outer periphery of the partition gate 15, respectively engaging within each guide groove 16 to form a sliding pair structure, ensuring smooth movement and accurate positioning of the partition gate 15.

[0032] Because the discharge adjustment zone 10 adopts a sealed structure design, it can effectively prevent liquid intrusion into the fixed outer cylinder 2 under normal operating conditions. However, considering that a small amount of filtrate may seep in reverse from the first discharge port 14 due to liquid inertia under extreme operating conditions, the electric push rod 18 is specially selected as an industrial-grade model with anti-corrosion and waterproof performance. The surface of the electric push rod 18 is chemically nickel-plated to form a corrosion-resistant protective film, ensuring reliable operation even when in contact with corrosive filtrate.

[0033] During operation, when the electric push rod 18 extends, it pushes the separating gate 15 to move towards the solid-liquid separation zone 9 until the separating gate 15 passes through the first discharge port 14, blocking the communication channel between the solid-liquid separation zone 9 and the first discharge port 14, and the edge of the separating gate 15 is completely in contact with the inner wall of the discharge adjustment zone 10 to form a reliable seal; when the electric push rod 18 retracts, it drives the separating gate 15 to move in the opposite direction, so that the solid-liquid separation zone 9 is connected to the first discharge port 14, thereby realizing the control of the hazardous waste flow channel.

[0034] Please refer to Figure 4 In some embodiments of this application, an annular sealing plate 20 is provided along the circumferential direction on the side of the dividing gate 15 facing the discharge adjustment area 10. The outer diameter of the annular sealing plate 20 is adapted to the inner diameter of the discharge adjustment area 10 to form a surface contact sealing structure, thereby achieving full coverage sealing of multiple first discharge ports 14.

[0035] When in dehydration mode, the separating gate 15 moves to the first preset position driven by the electric push rod 18. At this time, the annular sealing plate 20 is completely fitted with the edge of the first discharge port 14, forming an effective sealing surface and blocking the communication path between the solid-liquid separation zone 9 and the first discharge port 14. This design can prevent liquid in the fixed outer cylinder 2 from flowing back into the discharge adjustment zone 10 through the first discharge port 14 during centrifugal dehydration, thus preventing corrosion or mechanical damage to the driving components such as the electric push rod 18.

[0036] Please refer to Figure 4 In some embodiments of this application, a plurality of unblocking components are uniformly installed on the outer periphery of the annular sealing plate 20 along the circumferential direction. Each unblocking component corresponds one-to-one with the position of the corresponding first discharge port 14. The unblocking components can move synchronously with the annular sealing plate 20 to clean the first discharge port 14.

[0037] To address the potential blockage at the first discharge port 14 due to material adhesion or agglomeration during long-term discharge, the unblocking component extends into the first discharge port 14 when the partition gate 15 moves the annular sealing plate 20. This component mechanically scrapes away material residue adhering to the inner wall of the discharge port and breaks up any agglomerated material, ensuring unobstructed discharge channel 26. During operation, the unblocking component performs a periodic cleaning action with the reciprocating motion of the annular sealing plate 20, effectively preventing material accumulation, maintaining the continuous discharge efficiency of the first discharge port 14, reducing the frequency of manual intervention, and improving the level of automation.

[0038] Specifically, the unblocking component adopts an elastic self-resetting structure, which includes an unblocking contact 23, an elastic element 22, and an assembly channel 21. The assembly channel 21 is embedded in the circumferential surface of the annular sealing plate 20 and extends radially; one end of the elastic element 22 (preferably a compression spring) is fixedly connected to the bottom wall of the assembly channel 21, and the other end is rigidly connected to the unblocking contact 23; the unblocking contact 23 forms a clearance fit with the inner wall of the assembly channel 21 and can slide and guide radially along the assembly channel 21; the end of the unblocking contact 23 is provided with a guide arc 24 that matches the contour of the inner wall of the first discharge port 14.

[0039] When the partition gate 15 is in the initial position, the unblocking contact 23 is squeezed by the inner wall of the discharge adjustment zone 10, compressing the elastic element 22 and storing it in the assembly channel 21; when the first discharge port 14 needs to be cleaned, as the partition gate 15 moves axially, the unblocking contact 23 is aligned with the first discharge port 14, and the elastic element 22 releases the pre-tightening force to push the unblocking contact 23 to extend radially, so that the guide arc 24 at the end of the unblocking contact 23 is precisely inserted into the inner wall of the first discharge port 14, and the blockage is broken and the adhering residue is scraped off through mechanical contact.

[0040] When the unblocking contact 23 completes its operation and disengages from the first discharge port 14, the guide arc 24 at the end of the unblocking contact 23 forms an inclined contact with the inner wall of the first discharge port 14. The pressure is decomposed into a radial component along the guide arc 24. This component drives the unblocking contact 23 to retract along the assembly groove 21, ensuring that the unblocking contact 23 automatically resets and disengages from the first discharge port 14, avoiding interference with the subsequent discharge process. This structure, through elastic adaptive adjustment and inclined guide cooperation, achieves an integrated function of unblocking and component reset, effectively improving the unblocking efficiency and reliability of the discharge port.

[0041] Please refer to Figure 5 In some embodiments of this application, the drive assembly adopts an external gear transmission structure, specifically including a motor 5, a driving gear 6, a driven gear 25, and a central drive shaft 19. The motor 5 is fixedly installed on the outer side of the end of the fixed outer cylinder 2, and its output shaft is keyed to the driving gear 6; the central drive shaft 19 is coaxially arranged with the fixed outer cylinder 2, one end of which is rigidly connected to the top of the rotating inner cylinder 8 through a spline, and the other end extends out of the fixed outer cylinder 2 and extends to the outer side to be interference-fitted with the driven gear 25. The driving gear 6 and the driven gear 25 form an external meshing transmission pair.

[0042] The outer wall of the rotating inner cylinder 8 is evenly distributed with multiple annular grooves 13 along the axial direction; correspondingly, the inner wall of the fixed outer cylinder 2 is equipped with multiple annular bosses 12 along the axial direction. The size of the annular bosses 12 is adapted to the annular grooves 13 to form an embedded sliding pair structure.

[0043] When motor 5 starts, power is transmitted sequentially through driving gear 6 and driven gear 25 to the central drive shaft 19, driving the rotating inner cylinder 8 to rotate around its axis. By controlling the forward and reverse rotation and speed of motor 5, high-speed rotation during the dewatering stage and low-speed rotation during the unloading stage can be achieved. Since the drive assembly is entirely located outside the fixed outer cylinder 2, the corrosion of the transmission components by corrosive filtrate is effectively avoided, significantly improving the reliability and ease of maintenance of the equipment.

[0044] Please refer to Figure 1 and Figure 3 In some embodiments of this application, the crushing assembly 3 is fixedly installed at a preset position via a base, and its structure includes a feed channel 4 and a discharge channel 26. The feed channel 4 has a funnel-shaped design that is wider at the top and narrower at the bottom. The inner wall is polished and has a guide slope, which can effectively guide hazardous waste to enter the crushing assembly 3 quickly and smoothly. The end of the discharge channel 26 is connected to the center of the end of the rotating inner cylinder 8 and is coaxially arranged with the central axis of the rotating inner cylinder 8 to ensure that the crushed material can fall into the rotating inner cylinder 8.

[0045] The crushing assembly 3 is equipped with a pair of counter-rotating crushing rollers, the roller surfaces of which are machined with staggered toothed structures. When hazardous waste is fed into the feed channel 4, it moves towards the discharge channel 26 under its own gravity. During this process, the hazardous waste is rapidly crushed to a preset size by the shearing and compressive forces between the two crushing rollers, and finally directly conveyed to the solid-liquid separation zone 9 of the rotating inner cylinder 8 through the discharge channel 26, providing uniformly sized raw materials for the subsequent centrifugal dewatering process.

[0046] For example, to further ensure the stable transport of hazardous waste, a screw conveyor structure can be integrated inside the discharge channel 26. This ensures that the crushed hazardous waste can be stably and efficiently fed into the rotating inner cylinder 8, effectively preventing hazardous waste adhesion and jamming.

[0047] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A hazardous waste incineration pretreatment device, characterized in that, include: Rack (1); A fixed outer cylinder (2) is installed on the frame (1), and a second discharge port (7) is provided at the bottom end of the fixed outer cylinder (2); A rotating inner cylinder (8) is coaxially installed inside the fixed outer cylinder (2). The rotating inner cylinder (8) has a solid-liquid separation zone (9) and a discharge adjustment zone (10). The discharge adjustment zone (10) has multiple first discharge ports (14) along the circumferential direction. A dividing gate (15) is installed inside the rotating inner cylinder (8). The dividing gate (15) can reciprocate along the axial direction of the discharge adjustment area (10) to switch the on / off state between the solid-liquid separation area (9) and the first discharge port (14). The crushing assembly (3) has a feed channel (4) and a discharge channel (26), the discharge channel (26) extending coaxially into the interior of the rotating inner cylinder (8).

2. The hazardous waste incineration pretreatment device according to claim 1, characterized in that, It also includes an electric push rod (18), which is installed on the inner wall of the discharge adjustment area (10). The output end of the electric push rod (18) is connected to the partition gate (15) and is used to drive the partition gate (15) to reciprocate linearly along the axial direction of the discharge adjustment area (10). The inner wall of the discharge adjustment area (10) is provided with a plurality of guide grooves (16) along the circumferential direction, and each guide groove (16) extends along the axial direction of the discharge adjustment area (10). The outer periphery of the partition gate (15) is equipped with a plurality of guide sliders (17) along the circumferential direction, and the plurality of guide sliders (17) are respectively engaged in the plurality of guide grooves (16).

3. The hazardous waste incineration pretreatment device according to claim 2, characterized in that, The dividing gate (15) is provided with an annular sealing plate (20) along the circumferential direction on the side facing the discharge adjustment area (10). The annular sealing plate (20) is adapted to the inner diameter of the discharge adjustment area (10), and the annular sealing plate can seal with multiple first discharge ports (14).

4. The hazardous waste incineration pretreatment device according to claim 3, characterized in that, Multiple unblocking components are installed on the outer periphery of the annular sealing plate (20) along the circumferential direction, and the multiple unblocking components can unblock the multiple first discharge ports (14) respectively.

5. The hazardous waste incineration pretreatment device according to claim 4, characterized in that, The unblocking assembly includes a blockage-clearing contact (23), an elastic element (22), and an assembly channel (21) provided on the surface of the annular sealing plate (20); One end of the elastic element (22) is connected to the bottom wall of the assembly channel (21), and the other end of the elastic element (22) is connected to the unblocking contact (23); One end of the unblocking contact (23) is slidably guided to the assembly channel (21), and the other end of the unblocking contact (23) is provided with a guide arc (24) that is guided to cooperate with the first discharge port (14).

6. The hazardous waste incineration pretreatment apparatus according to any one of claims 1 to 5, characterized in that, It also includes a drive assembly, which includes a motor (5), a drive gear (6), a driven gear (25), and a central drive shaft (19); The motor (5) is installed at one end of the fixed outer cylinder (2), and the output end of the motor (5) is connected to the drive gear (6); The central drive shaft (19) is coaxially arranged with the fixed outer cylinder (2). One end of the central drive shaft (19) is connected to the rotating inner cylinder (8), and the other end of the central drive shaft (19) is connected to the driven gear (25). The driven gear (25) meshes with the driving gear (6). The outer wall of the rotating inner cylinder (8) is provided with a plurality of annular grooves (13) along the axial direction; The inner wall of the fixed outer cylinder (2) is provided with a plurality of annular bosses (12) along the axial direction, and the plurality of annular bosses (12) are respectively engaged in the plurality of annular grooves (13).

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