Biomass power generation furnace front feeding cantilever screw

Abstract

The biomass power generation furnace front feeding cantilever screw provided by the application relates to the technical field of biomass power generation equipment and comprises a driving part and a feeding part. The driving part comprises a speed reducer, a driving shaft, a driving gear, a linkage gear, a driven gear, a rotary lifting disc, a driving piece, a positioning support, a driving part shell and a visual sensing assembly. The feeding part comprises a screw shaft, a feeding part shell and a rotary anti-blocking assembly. The biomass power generation furnace front feeding cantilever screw has the beneficial effects that: the rotary anti-blocking assembly and the screw shaft are coaxially and reversely rotated to form a shearing force, the breaking efficiency of soft straw blocking is improved, the blocking rate is greatly reduced, the gear meshing precision is accurately controlled by combining a visual camera and a laser displacement sensor, gear collision is avoided, the equipment operation reliability is significantly improved, two operation modes are supported to adapt to different materials, and the applicability is strong.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the technical field of biomass power generation equipment, and particularly relates to a biomass power generation furnace front feeding cantilever screw. BACKGROUND

[0002] With the transformation of global energy structure to clean energy, biomass power generation, as an environmentally friendly power generation method using agricultural waste (such as straw and rice husk), has an increasing proportion in China's energy system year by year. The furnace front feeding system is one of the core links of biomass power generation, and its stability directly determines the power generation efficiency. If the feeding is interrupted or the output fluctuates, it will lead to unstable boiler combustion and even cause a boiler shutdown accident.

[0003] The current biomass feeding system has a problem of entanglement in conveying soft yellow straw materials. Such materials are light and soft in texture, high in fiber content, and poor in flowability. In the feeding process, the materials are prone to form "bridges" and "arches" due to fiber entanglement. The materials accumulate in an arch shape at the feeding port, and the lower passage is blocked. Especially when the length of the straw is uneven, the entanglement problem is more serious. SUMMARY

[0004] 1. Technical problem to be solved by the present application:

[0005] The biomass power generation furnace front feeding cantilever screw provided by the present application solves the technical problems in the background art.

[0006] 2. Technical scheme:

[0007] To achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows: a biomass power generation furnace front feeding cantilever screw, comprising a driving part and a feeding part.

[0008] The driving part comprises a speed reducer, a driving shaft, a driving gear, a linkage gear, a driven gear, a rotating lifting disc, a driving piece, a positioning support, a driving part shell and a visual sensing assembly. The driving gear, the linkage gear and the driven gear are connected to each other. The driving piece comprises a cylinder, a U-shaped sleeve and a limiting seat. The U-shaped sleeve is connected to the telescopic end of the cylinder and is sleeved on the side edge of the rotating lifting disc. The visual sensing assembly comprises a visual camera and a laser displacement sensor arranged on the inner wall of the driving part shell.

[0009] The feeding part comprises a screw shaft, a feeding part shell and a rotating anti-blocking assembly. One end of the screw shaft is coaxially connected to the driving shaft through a shaft coupling. The screw shaft and the rotating anti-blocking assembly are located in the feeding part shell.

[0010] The rotation anti-blocking assembly is connected with the rotating lifting disc and located outside the spiral shaft, and the rotation anti-blocking assembly comprises a positioning framework and a plurality of sets of cutting knives which are detachably connected with the positioning framework.

[0011] Further, the driving shaft is connected with the speed reducer and the spiral shaft at both ends, the driving gear is axially fixedly connected with the driving shaft, and the positioning support is sleeved on the driving shaft.

[0012] Further, the driven gear is arranged in a mirror image with the driving gear, and one end of the driven gear is fixedly connected with the rotating lifting disc.

[0013] Further, the linkage gear is arranged beside the driven gear and the driving gear, and the driven gear and the driving gear are meshingly connected with the linkage gear.

[0014] Further, the positioning support has an extension end which is fixedly connected with the inner wall of the driving part shell, and the linkage gear is rotatably connected with the positioning support through a bearing.

[0015] Further, the rotating lifting disc has a plurality of rolling balls embedded on one side, the rolling balls are arranged in a ring shape, the rolling balls are matched with the corresponding end faces of the U-shaped sleeve, and the U-shaped sleeve is rollingly connected with the rotating lifting disc through the rolling balls.

[0016] Further, the positioning framework has a circular arc shape, and one end of the positioning framework is fixedly connected with the rotating lifting disc.

[0017] Further, the visual camera is arranged at the front end and the rear end inside the driving part shell respectively, and the laser displacement sensor is arranged at the upper end inside the driving part shell.

[0018] 3. Beneficial effects:

[0019] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects:

[0020] The rotation anti-blocking assembly and the spiral shaft rotate coaxially and reversely to form a shearing force, thereby improving the breaking efficiency of soft straw blockage, greatly reducing the blockage rate, accurately controlling the gear meshing precision by combining the visual camera and the laser displacement sensor, avoiding gear collision, and significantly improving the reliability of the equipment operation.

[0021] Supporting two operation modes to adapt to different materials, the cutting knives are detachable, the maintenance time is shortened, the structure is stable and can withstand various biomass loads, the operation noise is low, and the practicability and environmental protection are considered.

[0022] It should be noted that the structures not introduced in the present application are the same as the prior art or can be realized by using the prior art since they do not involve the design points and improvement direction of the present application, and thus are not described herein. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present application;

[0024] Figure 2 It is a schematic diagram of the overall structure of the present application from another angle;

[0025] Figure 3 It is a schematic diagram of the overall structure of the present application;

[0026] Figure 4 It is an enlarged schematic diagram of the local structure of the present application;

[0027] Figure 5 It is another schematic diagram of the local structure of the present application.

[0028] Reference signs:

[0029] 1, reduction motor; 2, drive shaft; 3, driving gear; 4, linkage gear; 5, driven gear; 6, rotating lifting disc; 7, air cylinder; 8, U-shaped clamping sleeve; 9, limiting seat; 10, positioning support; 11, drive part shell; 12, spiral shaft; 13, feeding part shell; 14, rotating anti-blocking assembly; 1401, positioning framework; 1402, cutter; 15, ball; 16, visual camera; 17, laser displacement sensor. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings, which show several embodiments of the present application. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0031] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "page", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," "provided with," and "located in" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] See attached document Figures 1-5 The biomass power generation furnace front feeding cantilever screw includes a drive unit and a feeding unit;

[0035] The drive unit includes a geared motor 1, a drive shaft 2, a drive gear 3, a linkage gear 4, a driven gear 5, a rotary lifting plate 6, a drive component, a positioning bracket 10, a drive unit housing 11, and a vision sensing component. The drive gear 3, linkage gear 4, and driven gear 5 are meshed with each other. The drive component includes a cylinder 7, a U-shaped sleeve 8, and a limit seat 9. The U-shaped sleeve 8 is connected to the telescopic end of the cylinder 7 and is fitted onto the side edge of the rotary lifting plate 6. The vision sensing component includes a vision camera 16 and a laser displacement sensor 17 disposed on the inner wall of the drive unit housing 11.

[0036] The feeding section includes a screw shaft 12, a feeding section housing 13, and a rotational anti-blocking component 14. One end of the screw shaft 12 is coaxially connected to the drive shaft 2 via a coupling. Both the screw shaft 12 and the rotational anti-blocking component 14 are located inside the feeding section housing 13. The rotational anti-blocking component 14 is connected to the rotary lifting plate 6 and is located outside the screw shaft 12. The rotational anti-blocking component 14 includes a positioning frame 1401 and multiple sets of cutters 1402. The multiple sets of cutters 1402 are detachably connected to the positioning frame 1401.

[0037] The geared motor 1 is fixed on the outer end face of the drive housing 11. Its output shaft is coaxially fixed to one end of the drive shaft 2 through a rigid coupling. The geared motor 1 adopts the planetary gear reduction type and has the function of speed reduction and torque increase. It can adapt to the low speed and high torque requirements required for biomass material conveying and prevent the screw shaft 12 from stopping due to excessive load.

[0038] The driving gear 3 is circumferentially positioned by a key with the driving shaft 2, and is axially fixed by the left side of the shaft shoulder on the driving shaft 2 and the right side of the locking nut, so as to prevent the driving gear 3 from moving axially when the driving shaft 2 rotates at high speed. The modulus and the number of teeth of the driving gear 3 are consistent with those of the driven gear 5, and are used for transmitting the rotary power of the driving shaft 2 to the linkage gear 4.

[0039] The positioning support 10 is a U-shaped steel structure, the center hole of which is sleeved outside the driving shaft 2 and leaves a certain gap with the driving shaft 2 to avoid rotating interference. One side of the positioning support 10 is provided with a flat plate-shaped extension end extending outward perpendicularly, and the extension end is threadedly connected with the inner wall of the driving part shell 11 through a bolt. The linkage gear 4 is rotatably connected with the positioning support 10 through a deep groove ball bearing, so as to ensure that the linkage gear 4 rotates flexibly during power transmission without jamming. The linkage gear 4 is fixed and supported by the positioning support 10, so as to ensure that it is always in the meshing position between the driving gear 3 and the driven gear 5, and avoid the gear offset from causing the gear impact or disengagement.

[0040] The driven gear 5 is mirror-symmetrically arranged with the driving gear 3. One side end face of the driven gear 5 is coaxially fixed with the rotary lifting disc 6 through a bolt. The rotary lifting disc 6 is an annular disc structure, and the inner hole thereof is gap-fitted with the driving shaft 2, so as to allow the rotary lifting disc 6 to freely move along the axial direction of the driving shaft 2, and to be synchronously rotated with the driven gear 5. The driven gear 5 is coaxially and reversely rotated with the driving gear 3 through the meshing with the linkage gear 4. After the driven gear 5 rotates, the power is transmitted to the rotary lifting disc 6, and then the coaxial and reverse rotation of the rotary anti-blocking assembly 14 and the spiral shaft 12 is driven, so as to realize the rotary cutting of the rotary anti-blocking assembly 14, and form a shearing force on the entangled material at the feeding port, so as to avoid the problem that the material is synchronously rotated with the spiral shaft 12 and cannot be dispersed.

[0041] The cylinder 7 is fixed on the limiting seat 9 in the driving part shell 11, and the telescopic end thereof is threadedly connected with the outer side end face of the horizontal plate of the U-shaped clamping sleeve 8 after penetrating through the limiting seat 9.

[0042] The U-shaped clamping sleeve 8 is composed of two parallel clamping plates and a horizontal plate connecting the clamping plates. The spacing between the clamping plates is adapted to the thickness of the rotary lifting disc 6, and the inner side end face of the clamping plate leaves a 0.2mm gap with the side edge of the rotary lifting disc 6 to avoid rotating interference. An annular ball groove is formed in the side end face of the rotary lifting disc 6 away from the driven gear 5, and a plurality of balls 15 are embedded in the groove. The balls 15 partially protrude from the groove and are in contact with and embedded in the inner side end face of the clamping plate of the U-shaped clamping sleeve 8, so that the U-shaped clamping sleeve 8 is in rolling connection with the rotary lifting disc 6, which does not affect the rotation of the rotary lifting disc 6, and can drive the rotary lifting disc 6 to move along the axial direction of the driving shaft 2 through the telescopic movement of the cylinder 7, thereby greatly reducing the moving friction resistance.

[0043] The limiting seat 9 is annular and cylindrical, fixed on the inner wall of the driving part shell 11, the U-shaped sleeve 8 and the rotating lifting disc 6 are located in the limiting seat 9, which is used to limit the movement path of the U-shaped sleeve 8, and ensure that the rotating lifting disc 6 only moves axially along the driving shaft 2, avoiding offset to cause the misalignment of the meshing of the driven gear 5 and the linkage gear 4.

[0044] The visual camera 16 is an industrial high-definition camera, fixed on the front and rear ends of the driving part shell 11 through the support, and the lens faces the meshing area of the driven gear 5 and the linkage gear 4, which can capture the tooth surface contact state of the two gears in real time, and output high-definition image signals to the control system to identify the tooth surface alignment before the gear meshing. If the tooth surface is not aligned, such as the tooth top opposite to the tooth top, the feedback signal is fed back to the control system to adjust the rotating speed of the driving shaft 2 to avoid the gear tooth impact during meshing.

[0045] The laser displacement sensor 17 is fixed on the upper end of the driving part shell 11, and the emitting end is vertically downward aligned with the tooth surface of the driven gear 5 to detect the axial position and rotating angle of the driven gear 5 in real time. When the rotating lifting disc 6 moves, the distance between the driven gear 5 and the linkage gear 4 is fed back. When the distance is reduced to the preset value of meshing, the control cylinder 7 stops extension and contraction to ensure the precise meshing of the two gears.

[0046] The spiral shaft 12 adopts seamless steel pipe welded spiral blade, and the blade pitch is adapted to the conveying efficiency of biomass materials. The spiral shaft 12 is coaxially connected with the driving shaft 2 through an elastic coupling. The inside of the feeding part shell 13 is a cylindrical body, one end of which is connected with the flange of the driving part shell 11, and the other end is connected with the feed pipe of the power generation furnace. The inner wall of the feeding part shell 13 leaves a gap with the blade of the spiral shaft 12 and the outer edge of the rotating anti-blocking assembly 14 to avoid material jamming. The upper end of the feeding part shell 13 is provided with a feed inlet.

[0047] The rotating anti-blocking assembly 14 includes a positioning framework 1401 and a plurality of cutters 1402. The positioning framework 1401 is made of stainless steel plate and is bent into a quarter of a circular arc shape, which is adapted to the curvature of the inner wall of the feeding part shell 13. One end of the positioning framework 1401 is fixed to the edge of the end surface of the rotating lifting disc 6 through bolts, and the other end extends to the area below the feed inlet of the feeding part shell 13 to cover the feed inlet area. The positioning framework 1401 provides installation support for the cutters 1402. The inner side of the positioning framework 1401 leaves a gap with the outer edge of the spiral shaft 12 to avoid interference with the spiral shaft 12.

[0048] The cutting edge of the cutter 1402 faces the feed inlet, and a plurality of cutters 1402 are evenly distributed along the length direction of the positioning framework 1401. The cutter 1402 is detachably connected to the outer arc surface of the positioning framework 1401 through bolts, and the extension length of the cutter 1402 can be adjusted to adapt to the cutting needs of different materials. The cutter 1402 can cut the biomass materials tangled at the feed inlet during rotation, such as the fiber entanglement of soft yellow straw, and can scatter the material groups of bridge and arch to ensure that the materials fall smoothly to the spiral shaft 12.

[0049] The specific embodiments of the technical solution are as follows:

[0050] Embodiment one

[0051] The edge-cutting and feeding conveying is suitable for processing materials with soft texture and serious fiber entanglement, such as soft yellow straw with water content of more than 30%, which is easy to form continuous entanglement at the feeding port and needs to be cut in real time to ensure smooth feeding. The operation process is as follows:

[0052] After the control system is started, the state of each component is detected by the visual camera 16 and the laser displacement sensor 17, and it is confirmed that the driven gear 5 and the linkage gear 4 are in a separated state, the rotary anti-blocking assembly 14 is stopped outside the feeding port, and the spiral shaft 12 is not jammed.

[0053] The operator sets the edge-cutting and feeding instruction through the control system, the telescopic end of the air cylinder 7 is extended, the U-shaped sleeve 8 is pushed to move to the right side along the limiting seat 9, and the rotary lifting disc 6 is driven to move axially along the drive shaft 2. During the movement, the laser displacement sensor 17 feeds back the position of the driven gear 5 in real time. When the distance between the driven gear 5 and the linkage gear 4 is detected to be reduced, the visual camera 16 takes a picture of the tooth surface. If the tooth surface is aligned with the tooth valley and the tooth top, the control system drives the air cylinder 7 to continue to extend, so that the two gears are completely engaged. If the tooth surface is not aligned, the control system drives the reduction motor 1 to rotate at a low speed to adjust the angle of the driven gear 3 to drive the linkage gear 4, until the tooth surface is aligned and then the engagement is completed.

[0054] After the gears are engaged, the reduction motor 1 is started, the drive shaft 2 drives the spiral shaft 12 to rotate, the spiral blade transports the materials falling from the feeding port to the power generation furnace, at the same time, the driven gear 5 is driven by the linkage gear 4 to rotate in the opposite direction, the rotary lifting disc 6 drives the rotary anti-blocking assembly 14 to rotate in the opposite direction coaxially with the spiral shaft 12, so that the cutter 1402 continuously cuts the materials entangled at the feeding port, and the dispersed materials directly fall between the blades of the spiral shaft 12, realizing the synchronous operation of cutting and conveying.

[0055] During operation, the visual camera 16 continuously monitors the gear engagement state. If the gears are disengaged, such as the driven gear is offset due to material impact, a feedback signal is immediately fed back, the rotary lifting disc 6 is quickly pushed by the air cylinder 7 to compensate the position, to ensure the stable engagement, and the axial position of the rotary lifting disc 6 is monitored by the laser displacement sensor 17, to avoid the displacement deviation caused by vibration.

[0056] Embodiment two

[0057] Only start cutting when plugging, adapt to low entanglement material, suitable for processing better flow, occasionally plugging material such as dry corn straw with water content below 15%, such material does not need to be cut when normal conveying, only start anti-blocking component when bridge and arch appear in feeding port, can reduce energy consumption and cutter wear, operation process as follows:

[0058] After the control system is started, the telescopic end of the air cylinder 7 is in the retracted state, driving the rotating lifting plate 6 to move away from the side of the linkage gear 4, so that the driven gear 5 is completely separated from the linkage gear 4, and the rotating anti-blocking assembly 14 is stationary in the non-feeding area of the feeding part shell 13 under the positioning of the laser displacement sensor 17, avoiding blocking the material falling;

[0059] The speed reducer motor 1 is started, the driving shaft 2 drives the spiral shaft 12 to rotate, and the material falls from the feeding port of the feeding part shell 13 to the power generation furnace. In the process, the pressure sensor arranged at the feeding port of the feeding part shell 13 detects the material pressure of the feeding port in real time. If the pressure is lower than the threshold, it is determined that there is no plugging, and the rotating anti-blocking assembly 14 remains stationary.

[0060] When the feeding port is plugged, such as material bridge causes accumulation, the pressure sensor detects that the pressure is higher than the threshold, and immediately sends a plugging signal to the control system. After receiving the signal, the control system first reduces the speed of the speed reducer motor 1 to reduce the continuous accumulation of material, and then the air cylinder 7 is extended to push the rotating lifting plate 6 to make the driven gear 5 mesh with the linkage gear 4. The meshing control logic is the same as in the first embodiment. After the rotating anti-blocking assembly 14 is started, it rotates coaxially and reversely with the spiral shaft 12. Through reverse rotation, it can play the role of dispersing the plugging group during cutting. Until the pressure sensor detects that the pressure decreases, it is confirmed that the plugging is eliminated. Compared with the same direction rotation, the reverse rotation can shorten the plugging breaking time and avoid the material being compacted by the spiral shaft 12 to form more difficult plugging.

[0061] After the plugging is eliminated, the control system issues a reset command to control the speed reducer motor 1 to rotate at a low speed, so that the rotating anti-blocking assembly 14 returns to the standby position on the side of the feeding port. Then the speed reducer motor 1 returns to the working speed, and the spiral shaft 12 continues to normally convey the material.

[0062] In summary, the device is horizontally arranged and divided into two modules, driving part and feeding part. The power transmission is realized through the coaxial connection of the driving shaft 2 and the spiral shaft 12. The driving part provides power for the feeding part and the anti-blocking cutting power. The feeding part is responsible for the stable conveying of biomass material. The whole is packaged in a shell structure, which is suitable for the feeding scene before the biomass power generation furnace. It can realize anti-blocking conveying for different characteristics of soft yellow straw, corn straw and other materials.

[0063] The above-described embodiments only express some implementation manners of the present application, which are described in a more specific and detailed manner, but should not be understood as a limitation on the patent scope of the present application; it should be noted that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application; therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A biomass power plant feedstock front end cantilever auger characterized by: The driving part and the feeding part are included; The driving part includes a reduction motor (1), a driving shaft (2), a driving gear (3), a linkage gear (4), a driven gear (5), a rotating lifting disc (6), a driving element, a positioning support (10), a driving part shell (11) and a visual sensing assembly, the driving gear (3), the linkage gear (4) and the driven gear (5) are connected with each other in meshing mode, the driving element includes a cylinder (7), a U-shaped clamping sleeve (8) and a limiting seat (9), the U-shaped clamping sleeve (8) is connected with the telescopic end of the cylinder (7) and is sleeved on the side edge of the rotating lifting disc (6), the visual sensing assembly includes a visual camera (16) and a laser displacement sensor (17) arranged on the inner wall of the driving part shell (11), the visual camera (16) is respectively located at the front and rear ends inside the driving part shell (11), and the laser displacement sensor (17) is located at the upper end inside the driving part shell (11). The feeding part includes a spiral shaft (12), a feeding part shell (13) and a rotating anti-blocking assembly (14), one end of the spiral shaft (12) is coaxially connected with the driving shaft (2) through a shaft coupling, and the spiral shaft (12) and the rotating anti-blocking assembly (14) are located in the feeding part shell (13). The rotating anti-blocking assembly (14) is connected with the rotating lifting disc (6) and located outside the spiral shaft (12), the rotating anti-blocking assembly (14) includes a positioning framework (1401) and a plurality of cutter groups (1402), and the plurality of cutter groups (1402) are detachably connected with the positioning framework (1401). Both ends of the driving shaft (2) are connected with the reduction motor (1) and the spiral shaft (12), the driving gear (3) is axially fixedly connected with the driving shaft (2), and the positioning support (10) is sleeved on the driving shaft (2). The driven gear (5) is arranged in a mirror image mode with the driving gear (3), and one end of the driven gear (5) is fixedly connected with the rotating lifting disc (6). The linkage gear (4) is arranged beside the driven gear (5) and the driving gear (3), and the driven gear (5) and the driving gear (3) are in meshing connection with the linkage gear (4).

2. The biomass power plant front feeder cantilever auger of claim 1, wherein: The positioning support (10) has an extension end, the extension end is fixedly connected with the inner wall of the driving part shell (11), and the linkage gear (4) is rotationally connected with the positioning support (10) through a bearing.

3. The biomass power plant front feeder cantilever auger of claim 1, wherein: A plurality of rolling balls (15) are embedded on one side of the rotating lifting disc (6), the rolling balls (15) are arranged in an annular mode, the rolling balls (15) are matched with the end faces corresponding to the U-shaped clamping sleeve (8), and the U-shaped clamping sleeve (8) is rollingly connected with the rotating lifting disc (6) through the rolling balls (15).

4. The biomass power plant front feeder cantilever auger of claim 1, wherein: The positioning framework (1401) is in a circular arc shape, and one end of the positioning framework (1401) is fixedly connected with the rotating lifting disc (6).

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