Puller for disassembling diffuser of gas compressor

Abstract

The puller comprises a supporting disc, a plurality of jacking assemblies are evenly arranged on the portion, corresponding to the top end face of the compressor diffuser, of the supporting disc in the circumferential direction, and a plurality of pulling claw assemblies are evenly arranged on the portion, corresponding to an annular gap in the compressor diffuser, of the supporting disc in the circumferential direction. The supporting disc is provided with a supporting assembly corresponding to a positioning hole in the compressor diffuser. The pulling claw assembly comprises a pulling claw body, the pulling claw body vertically slides relative to the supporting disc and is in coupling connection with the supporting disc in a circumferential rotating mode, and an elastic pre-tightening part used for fixing the pulling claw body is arranged between the pulling claw body and the supporting disc. The drawing device can adapt to a narrow space in a diffuser shell to uniformly apply force and draw the diffuser in the circumferential direction, and it is guaranteed that the diffuser can be stably taken out of the diffuser shell.

Description

Technical Field

[0001] The utility model belongs to the technical field of compressor diffuser assembly and relates to a puller for disassembling a compressor diffuser. Background Art

[0002] After the compressor diffuser has been working for a long time, it is necessary to inspect and maintain the diffuser body inside the shell, and at this time, the diffuser body needs to be removed from the shell. In the prior art, a threaded column puller is usually provided at the shell opening, and the claws of the puller are inserted into the shell and hooked on the flanges around the diffuser, and then the threaded column is rotated, and the reaction force provided by the contact between the threaded column and the force point inside the diffuser drives the diffuser body to be pulled out of the shell.

[0003] The existing threaded column puller has the problem of being large in size. First, the claws are not flexible enough to move. When facing a diffuser with a smaller size, it is often difficult for the claws to pass through the gap between the diffuser body and the shell, resulting in the claws being unable to hook the bottom of the flange of the diffuser body smoothly. Second, even if the claws are hooked with the bottom of the flange of the diffuser body, the movement of the diffuser during the subsequent pulling process will cause the claws to be unhooked from the bottom of the flange of the diffuser body, resulting in the failure of the pulling and disassembly of the diffuser. Third, the threaded column needs to abut against the force point and force surface inside the diffuser to provide a reverse pulling force. For diffusers of different models with a hollow internal structure, it is difficult to provide a stable force point for the threaded column.

[0004] Therefore, in view of the above-mentioned technical problems existing in the existing diffuser pulling tool, the utility model discloses a pulling tool for disassembling the compressor diffuser. Utility Model Content

[0005] The utility model aims to provide a pulling tool for disassembling a compressor diffuser, which can adapt to the narrow space inside the diffuser housing and pull the diffuser uniformly along the circumferential direction, so as to ensure that the diffuser can be smoothly taken out from the diffuser housing.

[0006] The utility model is realized by the following technical solutions:

[0007] A pulling tool for disassembling a compressor diffuser comprises a support plate, on which a plurality of lifting assemblies are evenly arranged along the circumferential direction corresponding to the top end surface of the compressor diffuser, on which a plurality of claw assemblies are evenly arranged along the circumferential direction corresponding to the annular gap on the compressor diffuser, and on which a support assembly is arranged corresponding to the positioning hole on the compressor diffuser; the claw assembly comprises a claw body, which is vertically slidable and circumferentially rotationally coupled with the support plate, and an elastic pre-tightening portion for fixing the claw body is arranged between the claw body and the support plate.

[0008] Place the support plate coaxially on the top end face of the compressor diffuser so that the support assembly on the support plate is connected to the positioning hole on the compressor diffuser to achieve the positioning of the support plate and prevent the support plate from moving during the subsequent pulling process. Rotate the claw assembly relative to the support plate so that the claw body in the claw assembly rotates to a direction tangent to the annular gap on the compressor diffuser, so that the claw assembly can pass through the annular gap smoothly. Then press the claw assembly downward so that the claw assembly passes through the annular gap downward under the compression of the elastic preload part and then reversely rotate the claw assembly so that the claw assembly rotates to a position where it is initially engaged with the diffuser. Open the claw assembly, and the claw assembly is firmly engaged with the diffuser under the elastic force of the elastic preload part. Then, the support plate can be lifted upward by synchronously operating the lifting assembly, and then the diffuser can be pulled out upward by the claw assembly to complete the disassembly of the diffuser.

[0009] In order to better realize the utility model, further, the claw body includes a claw mounting seat, a claw rod, and a claw head. The claw mounting seat is fixedly arranged on the support plate, and a mounting hole is arranged at the center of the claw mounting seat. The claw rod is inserted into the mounting hole and is vertically slidable and circumferentially rotatably coupled with the mounting hole. The bottom end of the claw rod is detachably mounted with a claw head, and an elastic pre-tightening portion is arranged between the top end of the claw rod and the top end surface of the support plate.

[0010] In order to better realize the utility model, further, the elastic pre-tightening part includes a spring nut and a pre-tightening spring which are sequentially sleeved on the outside of the top end of the claw rod from top to bottom, the spring nut is threadedly connected to the top end of the claw rod, and the pre-tightening spring is sleeved on the outside of the top end of the claw rod; the top end of the pre-tightening spring abuts against the bottom of the spring nut, and the bottom end of the pre-tightening spring abuts against the top of the claw mounting seat.

[0011] In order to better realize the utility model, further, a self-locking nut threadedly mounted on the outside of the top end of the claw rod is provided above the spring nut, and the self-locking nut drives the claw rod to rotate synchronously.

[0012] In order to better realize the utility model, further, the jacking assembly includes a jacking bolt and a supporting nut. The supporting nut is fixedly arranged on the supporting plate. A threaded hole is arranged at the center of the supporting nut. A jacking bolt is threadedly installed in the threaded hole. The bottom end of the jacking bolt abuts against the top end face of the compressor diffuser.

[0013] In order to better realize the utility model, further, the bottom end of the lifting bolt is detachably sleeved with a protective support sleeve, and the protective support sleeve abuts against the top end surface of the compressor diffuser.

[0014] In order to better realize the utility model, further, a jacking mounting hole is provided on the support plate, a support nut is inserted in the jacking mounting hole, a boss abutting the bottom end of the support nut is provided at the bottom end of the support plate, connecting screws are provided on both sides of the boss, and the connecting screws are threadedly connected to the support plate.

[0015] In order to better realize the utility model, further, the support assembly includes a support screw and a support rod. The support plate is provided with a support hole. The bottom end of the support screw passes downward through the support hole and is threadedly connected to the top of the support rod. The bottom of the support rod is provided with a positioning portion which is coaxially plugged into the positioning hole on the top end face of the compressor diffuser.

[0016] In order to better implement the utility model, further, the positioning portion includes a stepped positioning head.

[0017] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0018] (1) The utility model provides a support plate as a support base, and provides corresponding support components on the support plate corresponding to the positioning holes on the top end surface of the diffuser housing. The support components are connected with the positioning holes to provide a stable support force for the support plate, and the stability of the support plate is ensured, thereby ensuring the safety and stability of the subsequent process of pulling the diffuser, and avoiding the problem that the internal space of the diffuser housing is difficult to provide a fulcrum;

[0019] (2) The utility model arranges a plurality of claw assemblies on the support plate along the circumferential direction, and enables the claw body in the claw assembly to slide vertically relative to the support plate and to be coupled and connected in the circumferential rotation. The claw body is rotated to drive the claw head at the bottom of the claw body to rotate to a position tangent to the annular gap, thereby ensuring that the claw body and the claw head can smoothly pass through the annular gap to reach the bottom of the diffuser flange, and then the claw body is rotated in the reverse direction so that the claw head is initially engaged with the bottom of the diffuser flange, so as to adapt to the narrow space inside the diffuser for pulling operations;

[0020] (3) The utility model provides an elastic pre-tightening portion on the outside of the claw body. The elastic force provided by the elastic pre-tightening portion enables the claw head at the bottom end of the claw body to be firmly engaged with the bottom of the diffuser flange, effectively preventing the claw head from being separated from the bottom of the diffuser flange during the pulling process, and further ensuring the stability and safety of the diffuser pulling and disassembly process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0022] Figure 2 is a schematic diagram of the structure of the support plate;

[0023] Figure 3 It is a schematic diagram of the structure of the claw assembly;

[0024] Figure 4 It is a structural schematic diagram of the jacking assembly;

[0025] Figure 5 A schematic diagram of the structure of the support assembly.

[0026] Among them: 1-support plate; 2-lifting assembly; 3-claw assembly; 4-support assembly; 21-lifting bolt; 22-support nut; 23-protective support sleeve; 24-connecting screw; 31-claw mounting seat; 32-claw rod; 33-claw head; 34-self-locking nut; 35-spring nut; 36-preload spring; 41-support screw; 42-support rod. DETAILED DESCRIPTION

[0027] The following detailed descriptions are all illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the utility model. As used herein, unless the utility model explicitly states otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0030] Terminology explanation section: The terms "install", "connect", "connect", "fixed" and so on in the present utility model should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements, or an interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0031] Embodiment 1:

[0032] A puller for disassembling a compressor diffuser according to this embodiment, such as Figure 1 and Figure 2 As shown, it includes a support plate 1, on which a plurality of lifting assemblies 2 are evenly arranged along the circumferential direction corresponding to the top end surface of the compressor diffuser, on which a plurality of claw assemblies 3 are evenly arranged along the circumferential direction corresponding to the annular gap on the compressor diffuser, on which a support assembly 4 is arranged corresponding to the positioning hole on the compressor diffuser on the support plate 1; the claw assembly 3 includes a claw body, which is vertically slidable and circumferentially rotatably coupled with the support plate 1, and an elastic pre-tightening portion for fixing the claw body is arranged between the claw body and the support plate 1.

[0033] 6-8 groups of claw assemblies 3 and 6-8 groups of lifting assemblies 2 are evenly arranged on the support plate 1 along the circumferential direction. At the same time, corresponding support assemblies 4 are arranged on the support plate 1 corresponding to the positions and numbers of the positioning holes on the top end surface of the compressor diffuser. The support plate 1 is stably installed on the top of the compressor diffuser 5 by positioning and plugging between the support assemblies 4 and the positioning holes.

[0034] A plurality of claw mounting holes are arranged on the support plate 1 along the circumferential direction, and the claw assembly 3 is slidably inserted into the claw mounting holes along the vertical direction, and the claw assembly 3 can rotate circumferentially inside the claw mounting holes. When installing the support plate 1, firstly rotate each claw assembly 3 so that the bottom end of the claw body of the claw assembly 3 rotates to a position tangent to the annular gap on the compressor diffuser, and at this time, the bottom end of the claw body can smoothly pass through the annular gap, avoiding interference with the compressor diffuser during the installation of the support plate 1. After the support plate 1 is installed in place, the bottom end of the claw body passes through the annular gap, and the claw body is pressed downward to compress the elastic preload part, and the claw body is rotated in the reverse direction so that the bottom end of the claw body is clamped with the bottom of the flange of the diffuser, and then the claw body is loosened so that the claw body is reset upward under the elastic force of the elastic preload part, so that the bottom end of the claw body is tightly and firmly clamped with the bottom of the flange of the diffuser. Then, a plurality of groups of jacking assemblies 2 can be synchronously rotated by a wrench, and an upward jacking force can be applied to the support plate 1 by the jacking assemblies 2, and then the diffuser can be pulled out of the housing for disassembly by the claw assemblies 3.

[0035] Compared with the traditional claws with force applied by threaded columns, the puller structure in this embodiment avoids the need for the threaded column to set a force point inside the diffuser, and is more suitable for the hollow structure of the diffuser. At the same time, the claw assembly 3 in this embodiment can rotate circumferentially relative to the support plate 1, so that the pulling end at the bottom of the claw body can smoothly pass through the annular gap, ensuring that the claw body can be smoothly engaged with the diffuser in a narrow space.

[0036] Embodiment 2:

[0037] The puller for disassembling the compressor diffuser of this embodiment is improved on the basis of embodiment 1, such as Figure 3 As shown, the claw body includes a claw mounting seat 31, a claw rod 32, and a claw head 33. The claw mounting seat 31 is fixedly arranged on the support plate 1. A mounting hole is arranged at the center of the claw mounting seat 31. The claw rod 32 is inserted into the mounting hole and is vertically slidable and circumferentially rotatably coupled with the mounting hole. The bottom end of the claw rod 32 is detachably mounted with the claw head 33. An elastic pre-tightening portion is arranged between the top end of the claw rod 32 and the top end surface of the support plate 1.

[0038] The support plate 1 is provided with a threaded hole, and the bottom end of the claw mounting seat 31 is provided with an external thread to realize the threaded fixing installation of the claw mounting seat 31 on the support plate 1. A mounting hole is provided at the center of the claw mounting seat 31, and the lower end of the claw rod 32 is an optical axis section, which is coupled with the mounting hole for vertical sliding and circumferential rotation, so that the claw rod 32 can slide vertically and rotate circumferentially relative to the support plate 1. The upper end of the claw rod 32 is a threaded section, and the outer sleeve of the threaded section is provided with an elastic pre-tightening part. The bottom end of the claw rod 32 is detachably mounted with a claw head 33 through a connecting screw, and the claw head 33 is provided with any one of a slot, a bayonet, and a snap-on anti-slip pattern corresponding to the bottom of the flange of the diffuser.

[0039] The claw rod 32 is rotated to drive the claw head 33 to rotate, and the claw head 33 is ensured to smoothly pass through the annular gap and reset to a position where it can be engaged with the bottom of the diffuser flange. The claw rod 32 is vertically pressed to drive the claw head 33 to move vertically to smoothly pass through the annular gap and be engaged with the bottom of the diffuser flange. At the same time, the elastic pre-tightening part is compressed when the claw rod 32 is pressed. When the claw head 33 is engaged with the bottom end of the diffuser flange, the claw rod 32 is released. At this time, the claw rod 32 rebounds upward and resets under the elastic force of the elastic pre-tightening part, so that the claw head 33 can be firmly engaged with the bottom of the diffuser flange, avoiding the claw head 33 from being separated from the bottom of the diffuser flange during the subsequent pulling of the diffuser.

[0040] Furthermore, the elastic pre-tightening portion includes a spring nut 35 and a pre-tightening spring 36 which are sequentially sleeved on the outside of the top end of the claw rod 32 from top to bottom, the spring nut 35 is threadedly connected to the top end of the claw rod 32, and the pre-tightening spring 36 is sleeved on the outside of the top end of the claw rod 32; the top end of the pre-tightening spring 36 abuts against the bottom of the spring nut 35, and the bottom end of the pre-tightening spring 36 abuts against the top of the claw mounting seat 31.

[0041] When the claw rod 32 slides downward under the force, the spring nut 35 is driven to move downward to compress the preload spring 36. After the claw rod 32 is released, the preload spring 36 returns to its original state and provides elastic force so that the spring nut 35 drives the claw rod 32 to slide upward, thereby enabling the claw head 33 at the bottom end of the claw rod 32 to be firmly engaged with the bottom of the diffuser flange.

[0042] The other parts of this embodiment are the same as those of Embodiment 1, and thus will not be described in detail.

[0043] Embodiment 3:

[0044] The puller for disassembling the compressor diffuser of this embodiment is improved on the basis of embodiment 1 or 2, such as Figure 3 As shown, a self-locking nut 34 is also provided above the spring nut 35 and is threadedly sleeved on the outside of the top end of the claw rod 32. The self-locking nut 34 drives the claw rod 32 to rotate synchronously.

[0045] The self-locking nut 34 is threadedly connected to the threaded section at the top of the claw rod 32. At the same time, the self-locking structure of the self-locking nut 34 ensures that the claw rod 32 can be driven to rotate synchronously when the self-locking nut 34 is turned by a wrench.

[0046] The other parts of this embodiment are the same as those of Embodiment 1 or 2, and thus will not be described in detail.

[0047] Embodiment 4:

[0048] The puller for disassembling the compressor diffuser of this embodiment is improved on the basis of any one of Embodiments 1-3, such as Figure 4 As shown, the jacking assembly 2 includes a jacking bolt 21 and a supporting nut 22. The supporting nut 22 is fixedly arranged on the supporting plate 1. A threaded hole is arranged at the center of the supporting nut 22. The jacking bolt 21 is threadedly installed in the threaded hole. The bottom end of the jacking bolt 21 abuts against the top end face of the compressor diffuser.

[0049] The support plate 1 is provided with a mounting hole, in which the support screw sleeve 22 is fixedly mounted, and the jacking bolt 21 passes downward through the threaded hole at the center of the support screw sleeve 22 and abuts against the top end surface of the diffuser. By rotating the jacking bolt 21, the threaded matching structure between the jacking bolt 21 and the threaded hole of the support screw sleeve 22 provides an upward jacking force to the support plate 1.

[0050] Furthermore, a protective support sleeve 23 is detachably provided at the bottom end of the jacking bolt 21, and the protective support sleeve 23 abuts against the top end surface of the compressor diffuser. By providing the protective support sleeve 23, the abutting end of the jacking bolt 21 can be effectively protected, thereby extending the service life of the jacking bolt 21.

[0051] Furthermore, the protective support sleeve 23 is a rubber sleeve.

[0052] The other parts of this embodiment are the same as any one of Embodiments 1-3, so they are not described again.

[0053] Embodiment 5:

[0054] A puller for disassembling a compressor diffuser in this embodiment is improved on the basis of any one of Embodiments 1-4, such as Figure 4 As shown, the support plate 1 is provided with a jacking mounting hole, a support nut 22 is inserted in the jacking mounting hole, the bottom end of the support nut 22 is provided with a boss abutting against the bottom end surface of the support plate 1, and connecting screws 24 are provided on both sides of the boss, and the connecting screws 24 are threadedly connected to the support plate 1.

[0055] The boss is provided to cooperate with the bottom end surface of the support plate 1, thereby realizing the axial limitation of the support screw sleeve 22, and preventing the support screw sleeve 22 from axial movement. Half holes are provided on both sides of the boss, and a threaded hole is provided on the bottom end surface of the support plate 1. The connecting screw 24 passes through the half hole and is threadedly connected with the threaded hole on the bottom end surface of the support plate 1, thereby realizing the fixed installation of the support screw sleeve 22 on the support plate 1.

[0056] The other parts of this embodiment are the same as any one of Embodiments 1-4, so they are not described again.

[0057] Embodiment 6:

[0058] The puller for disassembling the compressor diffuser of this embodiment is improved on the basis of any one of Embodiments 1-5, such as Figure 5 As shown, the support assembly 4 includes a support screw 41 and a support rod 42. A support hole is provided on the support plate 1. The bottom end of the support screw 41 passes downward through the support hole and is threadedly connected to the top of the support rod 42. The bottom of the support rod 42 is provided with a positioning portion coaxially plugged into the positioning hole on the top end face of the compressor diffuser.

[0059] The support hole is a stepped hole, through which the support screw 41 passes, and the threaded section at the bottom end of the support screw 41 is threadedly connected with the threaded hole at the top of the support rod 42, and the top end face of the support rod 42 is in contact with the bottom end face of the support plate 1, and the bottom end of the support rod 42 is a positioning part that is connected to the positioning hole. The positioning part is inserted into the positioning hole, thereby realizing the support of the support rod 42 to the support plate 1, and positioning the support plate 1 at the same time to prevent the support plate 1 from rotating in the circumferential direction.

[0060] Furthermore, the positioning portion includes a stepped positioning head, and the positioning hole on the support plate 1 is correspondingly configured as a stepped hole.

[0061] The other parts of this embodiment are the same as any one of Embodiments 1-5, so they are not described again.

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A puller for disassembling a compressor diffuser, comprising a support plate (1), characterized in that: A plurality of lifting assemblies (2) are evenly arranged on the support plate (1) along the circumferential direction corresponding to the top end surface of the compressor diffuser, a plurality of claw assemblies (3) are evenly arranged on the support plate (1) along the circumferential direction corresponding to the annular gap on the compressor diffuser, and a support assembly (4) is arranged on the support plate (1) corresponding to the positioning hole on the compressor diffuser; the claw assembly (3) comprises a claw body, the claw body is vertically slidable and circumferentially rotatably coupled to the support plate (1), and an elastic pre-tightening portion for fixing the claw body is arranged between the claw body and the support plate (1).

2. A pulling tool for disassembling a compressor diffuser according to claim 1, characterized in that: The claw body comprises a claw mounting seat (31), a claw rod (32), and a claw head (33); the claw mounting seat (31) is fixedly mounted on the support plate (1); a mounting hole is provided at the center of the claw mounting seat (31); the claw rod (32) is inserted into the mounting hole and is vertically slidable relative to the mounting hole and coupled to the mounting hole for circumferential rotation; the claw head (33) is detachably mounted on the bottom end of the claw rod (32); and an elastic pre-tightening portion is provided between the top end of the claw rod (32) and the top end surface of the support plate (1).

3. A pulling tool for disassembling a compressor diffuser according to claim 2, characterized in that: The elastic pre-tightening portion comprises a spring nut (35) and a pre-tightening spring (36) which are sequentially sleeved on the outside of the top end of the claw lever (32) from top to bottom; the spring nut (35) is threadedly connected to the top end of the claw lever (32); the pre-tightening spring (36) is sleeved on the outside of the top end of the claw lever (32); the top end of the pre-tightening spring (36) abuts against the bottom end of the spring nut (35), and the bottom end of the pre-tightening spring (36) abuts against the top of the claw mounting seat (31).

4. A pulling tool for disassembling a compressor diffuser according to claim 3, characterized in that: A self-locking nut (34) is also provided above the spring nut (35) and is threadedly sleeved on the outside of the top end of the claw lever (32). The self-locking nut (34) drives the claw lever (32) to rotate synchronously.

5. A pulling tool for disassembling a compressor diffuser according to any one of claims 1 to 4, characterized in that: The jacking assembly (2) comprises a jacking bolt (21) and a supporting nut (22). The supporting nut (22) is fixedly arranged on the supporting plate (1). A threaded hole is arranged at the center of the supporting nut (22). The jacking bolt (21) is threadedly mounted in the threaded hole. The bottom end of the jacking bolt (21) abuts against the top end surface of the compressor diffuser.

6. A pulling tool for disassembling a compressor diffuser according to claim 5, characterized in that: The bottom end of the lifting bolt (21) is detachably sleeved with a protective support sleeve (23), and the protective support sleeve (23) abuts against the top end surface of the compressor diffuser.

7. A pulling tool for disassembling a compressor diffuser according to claim 6, characterized in that: The support plate (1) is provided with a lifting installation hole, a supporting screw sleeve (22) is inserted into the lifting installation hole, a boss abutting against the bottom end surface of the support plate (1) is provided at the bottom end of the support screw sleeve (22), connecting screws (24) are provided on both sides of the boss, and the connecting screws (24) are threadedly connected to the support plate (1).

8. A pulling tool for disassembling a compressor diffuser according to any one of claims 1 to 4, characterized in that: The support assembly (4) comprises a support screw (41) and a support rod (42); a support hole is provided on the support plate (1); the bottom end of the support screw (41) passes downward through the support hole and is threadedly connected to the top of the support rod (42); and a positioning portion is provided at the bottom of the support rod (42) and is coaxially plugged into a positioning hole on the top end surface of the compressor diffuser.

9. A pulling tool for disassembling a compressor diffuser according to claim 8, characterized in that: The positioning portion includes a stepped positioning head.

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