Surfacing welding equipment for metal materials

Abstract

The invention discloses surfacing welding equipment for metal materials, and relates to the field of welding equipment.The surfacing welding equipment comprises a heat source spray head and a lifting rod fixedly assembled at the top of the heat source spray head, the lifting rod is used for driving the heat source spray head to move up and down, and a feeding pipe is further fixedly erected on the outer side of the heat source spray head and used for providing metal powder materials; through the action of the slag removal unit and the auxiliary cooling unit, when the heat source spray head conducts surfacing machining on the surface of a metal workpiece, the motor operates to enable the lower end opening of the cooling air pipe to output high-speed airflow, the cooling speed of a heating welding part is increased, and the heat source spray head conducts surfacing machining on the surface of the metal workpiece, so that the heat source spray head conducts surfacing machining on the surface of the metal workpiece. And meanwhile, a welding slag layer is rapidly cooled and embrittled, then the welding slag layer can be frequently beaten under the operation of the slag removal unit, and therefore welding slag on the surface of the metal workpiece can be automatically beaten and removed, the labor cost is saved, and meanwhile the working efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of welding equipment, in particular to a surfacing welding equipment for metal materials. Background Art

[0002] The cladding process is a process in which alloy powder is heated by a heat source. The high temperature generated by the heat source can melt the alloy powder accumulated on the surface of the workpiece and cause it to flow and diffuse. After solidification and cooling, a high-performance coating can be formed, thereby achieving the goal of strengthening or hardening the metal surface, so that the surface of the metal workpiece has a metal layer that is wear-resistant, corrosion-resistant or has special properties.

[0003] During the cladding process, a thick layer of welding slag will be produced on the welded part of the workpiece surface, which is similar to a layer of welding slag skin on the workpiece surface. The welding slag needs to be removed after welding is completed. If the welding slag is not removed in time, it will affect the surface quality inspection of the cladding layer (such as pores, cracks, etc.), and if multi-layer cladding welding construction is carried out, the residual welding slag will also become slag inclusion defects, thereby weakening the bonding strength between the welding layers. The way to remove the welding slag is that the staff uses a slag hammer or a wire brush to clean the welding slag on the surface of the workpiece. If the surface area of ​​the workpiece is large (large metal workpieces such as discs or cylinders, etc.), the staff needs to move back and forth and use handheld tools to remove the welding slag. Because manual removal of welding slag is easy to consume physical strength, the workers cannot ensure that the welding slag is completely removed during the continuous work process, which easily causes a small amount of welding slag to remain on the workpiece surface. Summary of the Invention

[0004] The object of the present invention is to provide a cladding welding device for metal materials to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a cladding welding device for metal materials, comprising: a heat source nozzle and a lifting rod fixedly mounted on the top of the heat source nozzle, the lifting rod being used to move the heat source nozzle up and down, a feed pipe being fixedly mounted on the outside of the heat source nozzle, the feed pipe being used to provide metal powder material, the lower end of the feed pipe being inclined toward the lower end of the heat source nozzle, the metal powder material provided by the lower end of the feed pipe being able to cover the lower end of the heat source nozzle;

[0006] It also includes: a slag cleaning unit, used to knock off the welding slag layer on the surface of the metal workpiece, and the slag cleaning unit is arranged on a side of the heat source nozzle away from the feeding pipe;

[0007] The auxiliary cooling unit is used to increase the cooling speed of the welding part, and the auxiliary cooling unit is arranged between the heat source nozzle and the slag cleaning unit.

[0008] Preferably, the auxiliary cooling unit includes a frame fixed on the side of the heat source nozzle away from the feed pipe, and a cooling air duct fixedly suspended at the bottom of the frame, an electric motor is fixedly installed on the top of the frame, the output end of the motor faces downward, and a wind wheel is fixedly sleeved on the outer surface of the output end of the motor, and the wind wheel is placed at the inner top position of the cooling air duct, the bottom of the cooling air duct is bent, and the bottom port of the cooling air duct faces the side away from the bottom of the heat source nozzle, and the horizontal plane of the lower port of the cooling air duct is higher than the horizontal plane of the lower port of the heat source nozzle.

[0009] Preferably, a flat air nozzle is provided at the lower end of the cooling air duct, and the end of the flat air nozzle is in the shape of a long narrow opening.

[0010] Preferably, the slag cleaning unit includes a sleeve fixed to the lower end surface of the frame plate, and a sliding plate is slidably assembled inside the sleeve, and a sliding rod is concentrically arranged inside the sliding plate and slides through the sleeve, the sliding rod and the sliding plate are fixedly assembled, and both ends of the sliding rod extend out of the sleeve, and a first seat block is fixedly arranged at the end of the sliding rod away from the cooling air duct, and a positioning column is fixedly arranged inside the first seat block, a knocking rod is provided on the inner side of the first seat block, and the top of the knocking rod is hingedly assembled with a second seat block, the second seat block is fixedly assembled at the bottom of the frame plate, a straight groove is provided inside the knocking rod, and the positioning column is slidably assembled inside the straight groove, a sphere is also fixedly arranged at the bottom of the knocking rod, and a trigger component is also provided between the motor and the sleeve.

[0011] Preferably, the trigger component includes a worm sleeve fixedly mounted on the outer surface of the output end of the motor, and the worm sleeve is located between the cooling air duct and the frame plate, and a rotating shaft is rotatably mounted under the frame plate, and the rotating shaft and the worm sleeve are vertically distributed, and the outer surface of the rotating shaft is fixedly mounted with a worm gear assembled with the worm sleeve transmission, and the rotating shaft is fixedly mounted with a turntable at one end near the sleeve, and the turntable is also fixedly mounted with a plurality of trapezoidal oblique arc blocks equidistantly distributed around the circumference on one end face of the sleeve, the trapezoidal oblique arc blocks are in the shape of an isosceles trapezoid, and the end face of the slide rod close to the turntable is dome-shaped, and the end of the slide rod is in sliding contact with the inclined surface of the trapezoidal oblique arc block, and a first spring is fixedly arranged between the end of the slide plate away from the turntable and the sleeve.

[0012] Preferably, the end of the sliding rod does not contact the end surface of the rotating disk, and when the first spring is in an uncompressed state, there is a distance between the end of the sliding disk away from the first seat block and the sleeve.

[0013] Preferably, a fixing frame is fixedly provided on the top of the frame plate, and an arc sleeve and an arc guide rail are fixedly suspended on the bottom of the fixing frame, the sliding rod is rotatably assembled inside the sliding plate, and an arc piece is fixedly provided on the top of the second seat block, and the arc piece is slidably embedded in the inside of the arc guide rail, and a deflection component is also provided between the sliding rod and the rotating shaft.

[0014] Preferably, the deflection component includes a limiting rod fixed vertically on the outer wall of the sliding rod, and the exposed end of the limiting rod is fixedly provided with a connecting block, the interior of the arc sleeve is slidingly assembled with an arc rod, one end of the arc rod is fixedly docked with the connecting block, a second spring is also fixedly provided between the arc sleeve and the connecting block, and the second spring is sleeved on the outside of the arc rod, the outer surface of the rotating shaft is also fixedly sleeved with a cam, and the cam is in sliding contact with the limiting rod.

[0015] Preferably, the arc guide rail, the circular arc sleeve and the sleeve are all coaxially distributed.

[0016] Preferably, ventilation holes are provided at both ends of the sleeve.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention utilizes the functions of the slag cleaning unit and the auxiliary cooling unit. When the heat source nozzle performs surfacing welding on the surface of the metal workpiece, the operation of the motor can enable the lower port of the cooling air duct to output high-speed airflow, heat the cooling speed of the welding part, and quickly cool and embrittle the welding slag layer. Then, the operation of the slag cleaning unit can frequently knock the welding slag layer, thereby realizing automatic knocking and removal of the welding slag on the surface of the metal workpiece, saving labor costs and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 It is a front view of the present invention;

[0021] Figure 3 This is a schematic diagram of the cooling air duct and flat air nozzle structure of the present invention;

[0022] Figure 4 Schematic diagram of the internal structure of the sleeve of the present invention;

[0023] Figure 5 This is a schematic diagram of the arc piece and arc guide rail structure of the present invention;

[0024] Figure 6 This is a schematic diagram of the cam and limit rod structure of the present invention;

[0025] Figure 7 This is a schematic diagram of the second spring and arc rod structure of the present invention.

[0026] In the figure: 1. lifting rod; 2. frame plate; 3. heat source nozzle; 4. feed pipe; 5. cooling air duct; 6. motor; 7. wind wheel; 8. worm sleeve; 9. rotating shaft; 10. worm gear; 11. turntable; 12. trapezoidal oblique arc block; 13. sleeve; 14. sliding plate; 15. first spring; 16. sliding rod; 17. first seat block; 18. positioning column; 19. knocking rod; 20. straight groove; 21. sphere; 22. second seat block; 23. flat air nozzle; 24. cam; 25. limiting rod; 26. connecting block; 27. arc sleeve; 28. arc rod; 29. ​​second spring; 30. arc sheet; 31. arc guide rail; 32. fixing frame. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Example 1: Please refer to Figure 1-Figure 4 The illustrated embodiment of a cladding welding device for metal materials comprises a heat source nozzle 3 and a lifting rod 1 fixedly mounted on the top of the heat source nozzle 3. The lifting rod 1 is used to move the heat source nozzle 3 up and down. A feed pipe 4 is fixedly mounted on the outside of the heat source nozzle 3. The feed pipe 4 is used to supply metal powder material. The lower end of the feed pipe 4 is inclined toward the lower end of the heat source nozzle 3. The metal powder material provided by the lower end of the feed pipe 4 can cover the lower end of the heat source nozzle 3.

[0029] It also includes: a slag cleaning unit for knocking off the welding slag layer on the surface of the metal workpiece, and the slag cleaning unit is arranged on the side of the heat source nozzle 3 away from the feeding pipe 4;

[0030] The auxiliary cooling unit is used to increase the cooling speed of the welding part. The auxiliary cooling unit is arranged between the heat source nozzle 3 and the slag cleaning unit.

[0031] The auxiliary cooling unit includes a frame plate 2 fixed on the side of the heat source nozzle 3 away from the feed pipe 4, and a cooling air duct 5 fixedly suspended at the bottom of the frame plate 2. A motor 6 is fixedly installed on the top of the frame plate 2, and the output end of the motor 6 faces downward, and a wind wheel 7 is fixedly sleeved on the outer surface of the output end of the motor 6, and the wind wheel 7 is placed at the inner top position of the cooling air duct 5. The bottom of the cooling air duct 5 is bent, and the bottom port of the cooling air duct 5 faces the side away from the bottom of the heat source nozzle 3. The horizontal plane of the lower port of the cooling air duct 5 is higher than the horizontal plane of the lower port of the heat source nozzle 3. When the lifting rod 1 carries the heat source nozzle 3 for surfacing operation, the cooling air duct 5 will move along the trajectory of the heat source nozzle 3 behind the heat source nozzle 3. During the movement, the motor 6 can drive the wind wheel 7 to rotate at high speed, so that the lower port of the cooling air duct 5 can output high-speed airflow, thereby dissipating heat to the welding part on the surface of the metal workpiece and accelerating the cooling speed of the welding slag.

[0032] The lower end of the cooling air duct 5 is provided with a flat air nozzle 23. The end of the flat air nozzle 23 is in the shape of a long narrow strip. The flat air nozzle 23 can converge the transported air flow, thereby improving the cooling effect on the welding slag.

[0033] The slag cleaning unit includes a sleeve 13 fixed to the lower end surface of the frame plate 2, and a sliding plate 14 is slidably mounted inside the sleeve 13. A sliding rod 16 is concentrically arranged inside the sliding plate 14 and slides through the sleeve 13. The sliding rod 16 and the sliding plate 14 are fixedly assembled, and both ends of the sliding rod 16 extend out of the sleeve 13. A first seat block 17 is fixedly arranged at one end of the sliding rod 16 away from the cooling air duct 5, and a positioning column 18 is fixedly arranged inside the first seat block 17. A knock rod 19 is arranged on the inner side of the first seat block 17, and the top of the knock rod 19 is hingedly assembled with a The second seat block 22 is fixedly assembled on the bottom of the frame plate 2. A straight groove 20 is provided inside the knock rod 19, and the positioning column 18 is slidably assembled inside the straight groove 20. A sphere 21 is also fixedly provided on the bottom of the knock rod 19. A trigger component is also provided between the motor 6 and the sleeve 13. When the motor 6 drives the wind wheel 7 to rotate at high speed, it can also continuously touch the slide rod 16 through the trigger component, so that the slide rod 16 pushes the knock rod 19 away and then quickly resets elastically, so that the sphere 21 can elastically knock on the surface of the metal workpiece.

[0034] The trigger component includes a worm sleeve 8 fixedly mounted on the outer surface of the output end of the motor 6, and the worm sleeve 8 is located between the cooling air duct 5 and the frame 2. A rotating shaft 9 is also rotatably mounted below the frame 2, and the rotating shaft 9 and the worm sleeve 8 are vertically distributed. The outer surface of the rotating shaft 9 is fixedly sleeved with a worm wheel 10 assembled with the worm sleeve 8. A turntable 11 is fixedly mounted on one end of the rotating shaft 9 close to the sleeve 13, and a plurality of trapezoidal oblique arc blocks 12 equidistantly distributed around the circumference of the turntable 11 are also fixedly mounted on one end of the turntable 11 facing the sleeve 13. The trapezoidal oblique arc blocks 12 are in the shape of an isosceles trapezoid, and the slide rod 16 is close to the sleeve 13. One end face of the turntable 11 is dome-shaped, and the end of the slide rod 16 is in sliding contact with the inclined surface of the trapezoidal oblique arc block 12. A first spring 15 is fixedly arranged between the end of the slide plate 14 away from the turntable 11 and the sleeve 13. When the turntable 11 rotates with the trapezoidal oblique arc block 12, the slide rod 16 can be pushed first and then released instantly. During the release process, the reaction elastic force generated by the first spring 15 can quickly reset the slide rod 16. The slide rod 16 can pull the knock rod 19 through the action of the first seat block 17 and the positioning column 18, and knock the sphere 21 onto the welding slag layer on the surface of the metal workpiece.

[0035] The end of the slide rod 16 does not contact the end surface of the turntable 11, that is, there is a certain distance between the slide rod 16 and the turntable 11. When the first spring 15 is in an uncompressed state, there is a distance between the end of the sliding plate 14 away from the first seat block 17 and the sleeve 13. When the first spring 15 rebounds in reaction, it can avoid the sleeve 13 and the turntable 11 from hindering the reset movement of the sliding plate 14 and the slide rod 16, and can apply the rebound force to the knock rod 19 through the first seat block 17 to the greatest extent.

[0036] Example 2: Please refer to Figure 5-Figure 7 This embodiment is a further explanation of other embodiments. A fixing frame 32 is fixedly provided on the top of the frame plate 2, and an arc sleeve 27 and an arc guide rail 31 are fixedly mounted on the bottom of the fixing frame 32. The slide rod 16 is rotatably assembled inside the sliding plate 14. An arc piece 30 is fixedly provided on the top of the second seat block 22, and the arc piece 30 is slidably assembled inside the arc guide rail 31. A deflection component is also provided between the slide rod 16 and the rotating shaft 9. When the rotating shaft 9 rotates, the deflection component can be used to allow the slide rod 16 to swing back and forth, so that the knocking rod 19 can be deflected and moved back and forth, that is, the ball 21 can knock the welding slag layer in an S-moving manner.

[0037] The deflection component includes a limit rod 25 fixed vertically on the outer wall of the slide rod 16, and the exposed end of the limit rod 25 is fixedly provided with a connecting block 26. The interior of the arc sleeve 27 is slidably equipped with an arc rod 28, one end of the arc rod 28 is fixedly docked with the connecting block 26, and a second spring 29 is fixedly provided between the arc sleeve 27 and the connecting block 26, and the second spring 29 is sleeved on the outside of the arc rod 28. The outer surface of the rotating shaft 9 is also fixedly sleeved with a cam 24, and the cam 24 is in sliding contact with the limit rod 25. When the rotating shaft 9 rotates following the cam 24, it can push the limit rod 25 to cause the slide rod 16 to deflect.

[0038] The arc guide rail 31, the arc sleeve 27 and the sleeve 13 are all coaxially distributed, thereby ensuring that the knock rod 19 can swing smoothly left and right.

[0039] Ventilation holes are formed at both ends of the sleeve 13 . The function of the venting holes is to allow the sliding plate 14 to slide smoothly inside the sleeve 13 .

[0040] Working principle: When performing surfacing welding on the arc surface or horizontal surface of a metal workpiece, the feed pipe 4 can lay the metal powder material on the surface of the metal workpiece. The lifting rod 1 can heat and melt the metal powder while carrying the heat source nozzle 3 to allow the molten metal liquid to cover the surface of the metal workpiece. When the heat source nozzle 3 is running, the motor 6 will run synchronously, thereby driving the wind wheel 7 to rotate at high speed. At this time, a high-speed airflow will be generated at the bottom of the flat nozzle part 23. When the lifting rod 1 moves, the high-speed airflow can blow on the welding part, accelerating the cooling and solidification speed of the molten metal liquid, and also allowing the welding slag layer to quickly cool down and harden.

[0041] When the heat source nozzle 3 is operating, its position will continuously change on the surface of the metal workpiece. Under the cooperation of the worm sleeve 8 and the worm wheel 10, the operation of the motor 6 will cause the rotating shaft 9 to rotate with the turntable 11. The turntable 11 can continuously push the end of the slide rod 16 through the trapezoidal oblique arc block 12. At the same time, under the cooperation of the first spring 15, the slide rod 16 can push the knocking rod 19 through the first seat block 17, and then quickly reset and move, that is, the ball 21 can elastically knock on the surface of the cooled and solidified welding slag layer, knocking and cleaning the welding slag layer, thereby replacing the manual welding slag removal operation.

[0042] In this solution, when the rotating shaft 9 rotates with the cam 24, the slide bar 16 can be deflected by pushing the limit rod 25. At the same time, under the action of the second spring 29, when the cam 24 continues to rotate, the slide bar 16 can rotate with the knocking rod 19 through the first seat block 17. At the same time, the arc piece 30 also slides in cooperation inside the arc guide rail 31, so that when the heat source nozzle 3 moves on the surface of the metal workpiece, the sphere 21 can knock and remove the welding slag layer on the surface of the metal workpiece with an S-shaped motion trajectory, thereby further improving the cleaning effect of the welding slag layer.

[0043] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0044] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A cladding welding device for metal materials, characterized in that: include: A heat source nozzle (3) and a lifting rod (1) fixedly mounted on the top of the heat source nozzle (3); a feed pipe (4) is also fixedly mounted on the outside of the heat source nozzle (3); a lower end of the feed pipe (4) is inclined toward the lower end of the heat source nozzle (3); Also includes: A slag cleaning unit, used for knocking off the welding slag layer on the surface of the metal workpiece, wherein the slag cleaning unit is arranged on a side of the heat source nozzle (3) away from the feed pipe (4); An auxiliary cooling unit is used to increase the cooling speed of the welding part, and the auxiliary cooling unit is arranged between the heat source nozzle (3) and the slag cleaning unit.

2. The cladding welding equipment for metal materials according to claim 1, characterized in that: The auxiliary cooling unit comprises a frame (2) fixed on a side of the heat source nozzle (3) away from the feed pipe (4), and a cooling air duct (5) fixedly suspended at the bottom of the frame (2); a motor (6) is fixedly provided on the top of the frame (2), and a wind wheel (7) is fixedly sleeved on the outer surface of the output end of the motor (6), and the wind wheel (7) is placed on the inner side of the cooling air duct (5); the bottom of the cooling air duct (5) is bent, and the bottom port of the cooling air duct (5) faces the side away from the bottom of the heat source nozzle (3).

3. The cladding welding equipment for metal materials according to claim 2, characterized in that: The lower end of the cooling air duct (5) is provided with a flat air nozzle (23).

4. The cladding welding equipment for metal materials according to claim 2, characterized in that: The slag cleaning unit includes a sleeve (13) fixed to the lower end surface of the frame plate (2), and a sliding plate (14) is slidably mounted inside the sleeve (13), a sliding rod (16) is concentrically arranged inside the sliding plate (14) and slides through the sleeve (13), a first seat block (17) is fixedly arranged at one end of the sliding rod (16) away from the cooling air duct (5), and a positioning column (18) is fixedly arranged inside the first seat block (17), and the first seat block (17) A knock rod (19) is provided on the inner side, and the top of the knock rod (19) is hingedly assembled with a second seat block (22), and the second seat block (22) is assembled at the bottom of the frame plate (2). A straight groove (20) is opened inside the knock rod (19), and the positioning column (18) is slidably assembled inside the straight groove (20). A sphere (21) is also fixedly provided at the bottom of the knock rod (19), and a trigger component is also provided between the motor (6) and the sleeve (13).

5. The cladding welding equipment for metal materials according to claim 4, characterized in that: The trigger component includes a worm sleeve (8) fixedly sleeved on the outer surface of the output end of the motor (6); a rotating shaft (9) is rotatably mounted below the frame plate (2); a worm wheel (10) is fixedly sleeved on the outer surface of the rotating shaft (9) and is assembled with the worm sleeve (8); a turntable (11) is fixedly sleeved on one end of the rotating shaft (9) close to the sleeve (13); and a plurality of trapezoidal oblique arc blocks (12) equidistantly distributed around the circumference of the turntable (11) are fixedly mounted on one end of the turntable (11) facing the sleeve (13); the end of the slide rod (16) is in sliding contact with the inclined surface of the trapezoidal oblique arc block (12); and a first spring (15) is arranged between the end of the slide plate (14) away from the turntable (11) and the sleeve (13).

6. The cladding welding equipment for metal materials according to claim 5, characterized in that: The end of the sliding rod (16) does not contact the end surface of the rotating disk (11); when the first spring (15) is in an uncompressed state, there is a distance between the end of the sliding disk (14) away from the first seat block (17) and the sleeve (13).

7. The cladding welding equipment for metal materials according to claim 5, characterized in that: A fixing frame (32) is fixedly provided on the top of the frame plate (2), and a circular arc sleeve (27) and an arc guide rail (31) are fixedly suspended on the bottom of the fixing frame (32); the sliding rod (16) is rotatably assembled inside the sliding plate (14); a circular arc piece (30) is fixedly provided on the top of the second seat block (22), and the circular arc piece (30) is slidably assembled inside the arc guide rail (31); a deflection component is also provided between the sliding rod (16) and the rotating shaft (9).

8. The cladding welding equipment for metal materials according to claim 7, characterized in that: The deflection component includes a limiting rod (25) fixed on the outer wall of the sliding rod (16), and the exposed end of the limiting rod (25) is fixedly provided with a connecting block (26), the inner sliding assembly of the circular arc sleeve (27) is provided with an arc rod (28), one end of the circular arc rod (28) is fixedly docked with the connecting block (26), a second spring (29) is also fixedly provided between the circular arc sleeve (27) and the connecting block (26), and the outer surface of the rotating shaft (9) is also fixedly provided with a cam (24), and the cam (24) is in sliding contact with the limiting rod (25).

9. The cladding welding equipment for metal materials according to claim 8, characterized in that: The arc guide rail (31), the circular arc sleeve (27) and the sleeve (13) are all coaxially distributed.

10. The cladding welding equipment for metal materials according to claim 4, characterized in that: Both ends of the sleeve (13) are provided with ventilation holes.

Images