Negative pressure dust removal device

Abstract

The utility model belongs to the technical field of conveying belts, and discloses a negative pressure dust removal device which is arranged on a belt conveyor and comprises a top cover and a side sealing strip, the top cover is erected through a top cover support and buckled on the top face of a belt of the belt conveyor in the whole process, and the side sealing strip is arranged on the top face of the belt of the belt conveyor. The top edge of the side sealing strip is installed on the lower edge of the side wall of the top cover in a sealed mode, and an air draft seam is formed between the bottom edge of the side sealing strip and the top face of the belt in the length direction of the belt in a full-length mode. The air draft seam is formed between the bottom edge of the fan cover and the top face of the belt, negative pressure is formed at the air draft seam through the belt running at a high speed, dust leakage is avoided, and meanwhile dust on the outer side can be sucked in.

Description

Technical Field

[0001] The utility model relates to the technical field of conveyor belts, in particular to a negative pressure dust removal device. Background Art

[0002] In the field of material transportation, in order to improve the transportation rate of materials, belt conveyors are often used for material transportation. However, for powdery materials, dust is easily generated during transportation. Therefore, existing belt conveyors often add dust removal covers on the transportation path. An air duct is arranged at the top of the dust removal cover and connected to a bag filter and an axial flow fan. Negative pressure is formed on the conveyor belt through a power extraction method to prevent dust from spilling out.

[0003] However, for long-path belt conveyors, for belt conveyors dozens of meters or even hundreds of meters long, in order to ensure full negative pressure, a relatively large number of air duct interfaces often need to be connected and multiple negative pressure fans need to be equipped to achieve a certain negative pressure effect without dead angles throughout the process, so as to prevent powdery materials from spilling out. This power extraction method not only has defects such as high input cost and large energy consumption during operation, but also the long-distance air ducts are prone to dust collection and blockage failures.

[0004] In order to overcome the above problems, a negative pressure dust removal device is needed. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a negative pressure dust removal device, which forms an air extraction gap between the bottom edge of the air hood and the top surface of the belt, and uses the high-speed running belt to form negative pressure at the air extraction gap to prevent dust from leaking out, and at the same time can also suck in the outside dust.

[0006] To solve the above technical problems, the utility model adopts the following technical solutions:

[0007] A negative pressure dust removal device of the utility model is arranged on a belt conveyor and includes a top hood. The top hood is erected through a top hood bracket and is entirely buckled on the top surface of the belt of the belt conveyor. It also includes a side seal strip. The top edge of the side seal strip is hermetically installed on the lower edge of the side wall of the top hood. An air extraction gap that runs through along the length direction of the belt is formed between the bottom edge of the side seal strip and the top surface of the belt.

[0008] Furthermore, the air extraction gap is a uniformly consistent narrow gap, and the width range of the air extraction gap is set at 2-5 millimeters.

[0009] Furthermore, the side seal strip is made of a flexible polyurethane strip. The cross-section of the side seal strip is L-shaped, and the bottom short board thereof is opposite to the top surface of the belt to form the air extraction gap.

[0010] Further, an outer baffle is provided on the outer side of the bottom surface of the side seal strip, and a diversion strip is provided on the inner side. The bottom surfaces of the outer baffle and the diversion strip are located in the same plane; the number of the diversion strips is multiple and they are arranged at equal intervals along the length direction; the diversion strips are inclined and the inner ends are arranged in the same direction as the belt conveying direction.

[0011] Further, waist-shaped holes for connection are provided on the top vertical plate of the side seal strip, and the waist-shaped holes are arranged along the height direction of the cross-section.

[0012] Further, it further includes a hinge, an adapter plate, a setscrew and a mounting bolt. The top of the adapter plate is rotatably connected to the outer side wall of the top cover through the hinge; the side seal strip is connected to the bottom of the adapter plate through the mounting bolt; a threaded hole is provided in the upper part of the adapter plate and the setscrew is threadedly connected thereto, and the inner end of the setscrew abuts against the outer side wall of the bottom of the top cover.

[0013] Further, a lock nut is threadedly connected to the setscrew, and the lock nut is tightened against the outer wall of the adapter plate; the inner end of the setscrew is provided with a ball head, and the ball head contacts the outer side wall of the bottom of the top cover.

[0014] Further, it further includes a sealing strip, and the sealing strip seals the gap between the top edge of the adapter plate and the side wall of the top cover, and the sealing strip covers the hinge.

[0015] Further, the sealing strip is specifically made of a rubber plate, and both sides of the sealing strip are connected to the top of the adapter plate and the side wall of the top cover by rivets and press strips respectively.

[0016] The present utility model also discloses a working method of a negative pressure dust removal device, which uses the negative pressure dust removal device described in any one of the above to perform anti-leakage dust removal on the full stroke of the belt conveyor.

[0017] Compared with the prior art, the beneficial technical effects of the present utility model are as follows:

[0018] In the negative pressure dust removal device of the present utility model, the distance between the bottom edge of the top cover and the top surface of the belt is closed by setting a side seal strip, and a formed air extraction gap is formed between the bottom edge of the side seal strip and the top surface of the belt. When the belt conveyor is running at a high speed, the belt and the materials on the belt can drive the air between the top cover and the belt to flow towards the discharge end, and an air extraction from the outside to the inside can be formed at the air extraction gap, avoiding the outward escape of the powdered dust being conveyed, and at the same time, the outside dust can be sucked in to play an auxiliary dust removal effect. The side seal strip can replace the baffle plate, prevent material overflow, and avoid contacting the top surface of the belt and also avoid wearing of the belt.

[0019] In addition, ensuring that the width of the air extraction slit is uniform can guarantee an approximately constant air extraction pressure throughout the entire conveying process, avoiding air leakage caused by overly large local gaps and affecting the negative pressure air extraction for the entire process. By making the side seal strip from flexible polyurethane strips, which are soft materials facilitating deformation and installation, the belt will necessarily sag between two adjacent idlers. At this time, adjusting the fixed positions of the waist-shaped holes and the mounting bolts can downwardly adjust the installation position of the side seal strip, enabling it to deform along with the belt, thereby ensuring the uniformity of the air extraction slit. Through the arrangement of the guiding strip, a guiding cavity with an increased volume is added inside the outer baffle. Along the belt conveying direction, a negative pressure for pumping is formed using the Venturi principle. By connecting the adapter plate to the outer sidewall of the top cover with a hinge, the installation angle of the adapter plate can be adjusted, thereby ensuring that the bottom surface of the side seal strip is parallel to the top surface of the belt edge; through the arrangement of the setscrew, the outward turning angle of the adapter plate can be adjusted with high precision, facilitating installation and adjustment. By threadedly connecting a lock nut to the setscrew, loosening of the setscrew during operation is avoided, ensuring good stability. By sealing the gap between the top edge of the adapter plate and the sidewall of the top cover with a sealing strip, a rotatable sealing method can be formed, preventing air leakage here and preventing powder from overflowing from this location. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present utility model will be further described below in conjunction with the drawings.

[0021] Figure 1 FIG. is a schematic cross-sectional structure diagram of a belt conveyor with the negative pressure dust removal device of the present utility model;

[0022] Figure 2 FIG. is a schematic cross-sectional structure diagram of a belt conveyor with the negative pressure dust removal device of the present utility model in another embodiment;

[0023] Figure 3 For Figure 1 FIG. is a partially enlarged structure diagram of part I in FIG.

[0024] Figure 4 For Figure 2 FIG. is a schematic view of the structure as seen from direction A in FIG.

[0025] Figure 5 FIG. is a three-dimensional structure diagram of the side seal strip in the present utility model;

[0026] Figure 6 FIG. is a three-dimensional structure diagram of the side seal strip from another angle in the present utility model.

[0027] Description of reference numerals: 1. Top cover; 101. Top cover support; 2. Side seal strip; 201. Waist-shaped hole;

[0028] 202. Outer baffle; 203. Guiding strip; 3. Hinge; 4. Adapter plate; 5. Setscrew; 501. Ball head;

[0029] 502. Lock nut; 6. Installation bolt; 7. Sealing tape; 8. Belt conveyor; 801. Horizontal conveying idler; 802. Inclined conveying idler; 803. Belt; 9. Air extraction slot. Detailed implementation manners

[0030] The core of the present utility model is to provide a negative pressure dust removal device, which forms an air extraction slot between the bottom edge of the wind hood and the top surface of the belt, and uses the high-speed running belt to form a negative pressure at the air extraction slot to avoid dust leakage, and at the same time can suck in the outside dust.

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0032] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0033] Referring to the accompanying drawings, Figure 1 is a cross-sectional structure schematic diagram of a belt conveyor with the negative pressure dust removal device of the present utility model; Figure 2 is a cross-sectional structure schematic diagram of a belt conveyor with the negative pressure dust removal device of the present utility model in another embodiment; Figure 3 is for Figure 1 a partial enlarged structure schematic diagram of part I therein; Figure 4 is for Figure 2 a view structure schematic diagram in the A direction therein; Figure 5 is a three-dimensional structure schematic diagram of the side seal strip in the present utility model; Figure 6 is a three-dimensional structure schematic diagram of the side seal strip in another angle of the present utility model.

[0034] Embodiment 1

[0035] Such as Figure 1 , Figure 5 and Figure 6As shown in the figure, the negative pressure dust removal device of the present utility model is arranged on the belt conveyor 8 and includes a top cover 1. The top cover 1 is erected on the frame of the belt conveyor 8 through a top cover support 101. The top cover 1 is entirely buckled on the top surface of the belt 803 of the belt conveyor 8. The important innovation compared with the existing belt conveyor 8 is that the present utility model further includes a side seal strip 2. The top edge of the side seal strip 2 is hermetically installed on the lower edge of the side wall of the top cover 1, and an air extraction slit 9 extending along the length direction of the belt 803 is formed between the bottom edge of the side seal strip 2 and the top surface of the belt 803.

[0036] Specifically, as Figure 1 shown, when the belt 803 is a flat conveyor belt, the side seal strip 2 is directly installed at the bottom of the side wall of the top cover 1 through mounting bolts 6. Moreover, when the belt conveyor was used to convey powdery materials such as pulverized coal, coal ash or metal ore powder in the past, it was necessary to set a baffle to prevent overflow. However, the baffle contacts and rubs against the belt 803, which will damage the belt 803. The side seal strip 2 can replace the baffle, prevent overflow, and avoid wearing the belt 803 without contacting the top surface of the belt.

[0037] By setting the side seal strip 2 to close the distance between the bottom edge of the top cover 1 and the top surface of the belt 803, the formed air extraction slit 9 between the bottom edge of the side seal strip 2 and the top surface of the belt 803 can drive the air between the top cover 1 and the belt 803 to flow towards the discharge end under the high-speed operation of the belt conveyor 8, and a suction wind from the outside to the inside can be formed at the air extraction slit 9, avoiding the outward escape of the conveyed powdery dust. The side seal strip 2 can replace the baffle, prevent overflow, and avoid wearing the belt 803 without contacting the top surface of the belt.

[0038] In a specific embodiment of this embodiment, as Figure 1 shown, the air extraction slit 9 is a narrow slit with uniform width, and the width range of the air extraction slit 9 is set between 2 and 5 millimeters.

[0039] Ensuring that the width of the air extraction slit 9 is uniform can ensure that the suction pressure is approximately the same throughout the conveying process, avoiding air leakage caused by too large local gaps and affecting the negative pressure suction throughout the process.

[0040] In a specific embodiment of this embodiment, as Figure 1 、 Figure 5 and Figure 6 shown, the side seal strip 2 is made of a flexible polyurethane strip. The cross-section of the side seal strip 2 is L-shaped, and the bottom short plate forms an air extraction slit 9 opposite to the top surface of the belt 803. Along the length direction of the belt conveyor 8, multiple side seal strips 2 can be connected end to end for extension.

[0041] Specifically, as Figure 1 、 Figure 5 and Figure 6As shown in the figure, an outer baffle 202 is provided on the outer side of the bottom end surface of the side seal 2, and a flow guide strip 203 is provided on the inner side. The bottom surfaces of the outer baffle 202 and the flow guide strip 203 are located in the same plane. An air extraction slot 9 is formed between the bottom surface of the outer baffle 202 and the top surface of the belt 803. The number of the flow guide strips 203 is multiple and they are arranged at equal intervals along the length direction. The flow guide strips 203 are inclined and the inner ends are arranged in the same direction as the conveying direction of the belt 803.

[0042] Specifically, as Figures 4 to 6 shown in the figure, a waist-shaped hole 201 for connection is formed on the top vertical plate of the side seal 2, and the waist-shaped hole 201 is arranged along the height direction of the cross-section. The mounting bolt 6 passes through the waist-shaped hole 201 and is connected to the side wall of the top cover 1.

[0043] Since the side seal 2 is made of a flexible polyurethane strip, which is a soft material and convenient for deformation and installation, the belt 803 will necessarily sag at the position between two adjacent rollers. At this time, by adjusting the fixed positions of the waist-shaped hole 201 and the mounting bolt 6, the installation position of the side seal 2 can be adjusted downward to make it deform with the belt 803, thereby ensuring the uniformity of the air extraction slot 9. Through the arrangement of the flow guide strips 203, a flow guide cavity with an increased volume is added inside the outer baffle 202, and a negative pressure for pumping is formed along the conveying direction of the belt 803 by using the Venturi principle.

[0044] The working principle of this embodiment: During the normal operation of the belt conveyor 8, the running linear speed of the belt 803 is about 4 m / s. The belt 803 and the materials on the belt 803 drive the air between the top cover 1 and the belt 803 to flow from the feeding end to the discharging end. The high-speed flowing tunnel air forms an air extraction from the outside to the inside at the air extraction slot 9, avoiding the outward escape of the conveyed powder dust, and even being able to extract the dust in the environment around the belt 803. At the same time, the flow guide strips 203 guide the air extraction in the same direction, avoiding the blockage of materials and preventing the overflow of materials.

[0045] Embodiment 2

[0046] Most of the time, the conveying section of the belt 803 of the belt conveyor 8 is in a C shape with the opening facing upward, that is, the rollers below the belt 803 include a horizontal conveying roller 801 and inclined conveying rollers 802 arranged at both ends of the horizontal conveying roller 801. That is to say, the lower edge of the side wall of the top cover 1 and the top surface of the belt 803 are no longer perpendicular, forming an included angle. In order to ensure that the bottom surface of the side seal 2 is parallel to the belt 803, its installation structure needs to be improved. Therefore, the applicant has improved the installation structure of the side seal 2 on the basis of the above Embodiment 1.

[0047] As Figures 2 to 4As shown, the negative pressure dust removal device of the utility model also includes a hinge 3, an adapter plate 4, a top screw 5 and a mounting bolt 6. The top of the adapter plate 4 is rotatably connected to the outer wall of the top cover 1 through the hinge 3, and multiple hinges 3 can be arranged at intervals along the length direction of the top cover 1. The side seal 2 is connected to the bottom of the adapter plate 4 through the mounting bolt 6, and the mounting bolt 6 is also installed through the waist-shaped hole 201. A threaded hole is opened on the upper part of the adapter plate 4 and the top screw 5 is threadedly connected, and the inner end of the top screw 5 abuts against the outer wall of the bottom of the top cover 1.

[0048] Specifically, if Figures 2 to 4 As shown, a lock nut 502 is threadedly connected to the top screw 5, and the lock nut 502 is tightly backed on the outer wall of the adapter plate 4. The inner end of the top screw 5 is set as a ball head 501, and the ball head 501 contacts the outer side wall of the bottom of the top cover 1.

[0049] By using hinge 3 to connect adapter plate 4 to the outer wall of top cover 1, the installation angle of adapter plate 4 can be adjusted, thereby ensuring that the bottom surface of side seal 2 and the top surface of belt 803 edge are parallel; by setting top screw 5, the eversion angle of adapter plate 4 can be adjusted with high precision, which is convenient for installation and adjustment. By threading lock nut 502 on top screw 5, top screw 5 is prevented from loosening during operation, and stability is good.

[0050] In a specific implementation of this embodiment, Figure 3 As shown, the negative pressure dust removal device of the utility model further includes a sealing belt 7 , which seals the gap between the top edge of the adapter plate 4 and the side wall of the top cover 1 , and the sealing belt 7 covers the hinge 3 .

[0051] Specifically, if Figure 3 As shown, the sealing belt 7 is specifically made of a rubber plate, and both sides of the sealing belt 7 are connected to the top of the adapter plate 4 and the side wall of the top cover 1 by rivets and pressure strips respectively.

[0052] Obviously, the gap between the top edge of the adapter plate 4 and the side wall of the top cover 1 can also be sealed by applying sealant, that is, after adjusting the outward position of the adapter plate 4, use a glue gun to apply sealant along the top edge of the adapter plate 4, and form a stable seal after the sealant is cured.

[0053] The gap between the top edge of the adapter plate 4 and the side wall of the top cover 1 is sealed by the sealing belt 7, so that a rotatable sealing method can be formed to avoid air leakage here and prevent powder from overflowing from here.

[0054] Installation and commissioning process of this embodiment: First, weld the hinge 3 on the vertical outer wall of the top cover 1, and then weld the adapter plate 4 on the lower half of the hinge 3. Install the setscrew 5 and rotate the setscrew 5. The ball head 501 contacts the outer wall at the bottom of the top cover 1 and jacks up the adapter plate 4 to turn it outwards. Use a right-angle straightedge to measure the angle of the adapter plate 4. After ensuring that the side wall of the adapter plate 4 is perpendicular to the top surface of the edge of the belt 803, use the lock nut 502 to tighten against the outer wall of the adapter plate 4 to prevent the setscrew 5 from loosening. Install the side seal 2 and use the installation bolt 6 to pass through the waist-shaped hole 201 and the through-hole at the bottom of the adapter plate 4 for installation. Adjust the height position of the side seal 2 and flexibly adapt the installation along with the trend of the edge of the belt 803, so that the width of the air extraction slot 9 is uniform.

[0055] To sum up, for the negative pressure dust removal device of the present utility model, by setting the side seal 2 to enclose the distance between the bottom edge of the top cover 1 and the top surface of the belt 803, the formed air extraction slot 9 between the bottom edge of the side seal 2 and the top surface of the belt 803 can drive the air between the top cover 1 and the belt 803 to flow towards the discharge end under the high-speed operation of the belt conveyor 8. The materials on the belt 803 and the belt 803 can form an air extraction from the outside to the inside at the air extraction slot 9, avoiding the outward escape of the transported powder dust. The side seal 2 can replace the baffle plate, preventing material overflow and avoiding abrasion of the belt 803 without contacting the top surface of the belt. In addition, ensuring that the width of the air extraction slot 9 is uniform can ensure that the air extraction pressure is approximately the same throughout the conveying process, avoiding air leakage caused by too large local gaps and affecting the negative pressure air extraction throughout the process. By making the side seal 2 of flexible polyurethane strip, it is a soft material for easy deformation and installation. When the belt 803 droops inevitably between two adjacent idlers, at this time, adjust the fixed positions of the waist-shaped hole 201 and the installation bolt 6, and the installation position of the side seal 2 can be adjusted downwards to deform along with the belt 803, thereby ensuring the uniformity of the air extraction slot 9. Through the setting of the guide strip 203, a diversion cavity with an increased volume is added inside the outer baffle 202, and along the conveying direction of the belt 803, a negative pressure for pumping is formed using the Venturi principle. By connecting the adapter plate 4 to the outer wall of the top cover 1 with the hinge 3, the installation angle of the adapter plate 4 can be adjusted, thereby ensuring that the bottom surface of the side seal 2 is parallel to the top surface of the edge of the belt 803; through the setting of the setscrew 5, the outward turning angle of the adapter plate 4 can be adjusted with high precision, facilitating installation and adjustment. By threadedly connecting the lock nut 502 on the setscrew 5, the loosening of the setscrew 5 during operation can be avoided, and the stability is good. By sealing the gap between the top edge of the adapter plate 4 and the side wall of the top cover 1 with the sealing tape 7, a rotatable sealing method can be formed to avoid air leakage here and prevent the powder from overflowing from here.

[0056] Embodiment 3

[0057] The present utility model also discloses a working method of a negative pressure dust removal device, which uses the negative pressure dust removal device described in any one of the above to prevent leakage and remove dust from the entire stroke of a belt conveyor. The operation of the belt drives the air to form a negative pressure to prevent dust from spilling out.

[0058] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method part.

[0059] The above-described embodiments are only descriptions of the preferred modes of the present utility model, and do not limit the scope of the present utility model. Without departing from the design spirit of the present utility model, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present utility model shall fall within the protection scope determined by the claims of the present utility model.

Claims

1. A negative pressure dust removal device, arranged on a belt conveyor (8), comprising a top cover (1), wherein the top cover (1) is erected by a top cover bracket (101) and is fully buckled on the top surface of a belt (803) of the belt conveyor (8), characterized in that: It also includes a side seal strip (2), the top edge of which is sealingly mounted on the lower edge of the side wall of the top cover (1), and an exhaust slit (9) is formed between the bottom edge of the side seal strip (2) and the top surface of the belt (803) and is arranged along the length direction of the belt (803).

2. The negative pressure dust removal device according to claim 1, characterized in that: The ventilation slit (9) is a uniform narrow slit, and the width of the ventilation slit (9) is set in the range of 2 to 5 mm.

3. The negative pressure dust removal device according to claim 1, characterized in that: The side seal strip (2) is made of a flexible polyurethane strip, the cross section of the side seal strip (2) is L-shaped, and the bottom short plate is opposite to the top surface of the belt (803) to form the ventilation slot (9).

4. The negative pressure dust removal device according to claim 3, characterized in that: An outer baffle plate (202) is arranged on the outer side of the bottom end surface of the side seal strip (2) and a guide strip (203) is arranged on the inner side; the bottom surfaces of the outer baffle plate (202) and the guide strip (203) are located in the same plane; the guide strips (203) are multiple in number and are arranged at equal intervals along the length direction; the guide strips (203) are arranged obliquely and the inner ends are arranged in the same direction as the conveying direction of the belt (803).

5. The negative pressure dust removal device according to claim 4, characterized in that: A waist-shaped hole (201) for connection is provided on the top vertical plate of the side sealing strip (2), and the waist-shaped hole (201) is arranged along the height direction of the cross section.

6. The negative pressure dust removal device according to any one of claims 1 to 5, characterized in that: It also includes a hinge (3), an adapter plate (4), a top screw (5) and a mounting bolt (6); the top of the adapter plate (4) is rotatably connected to the outer wall of the top cover (1) through the hinge (3); the side seal (2) is connected to the bottom of the adapter plate (4) through the mounting bolt (6); a threaded hole is provided on the upper part of the adapter plate (4) and is threadedly connected to the top screw (5); the inner end of the top screw (5) abuts against the outer wall of the bottom of the top cover (1).

7. The negative pressure dust removal device according to claim 6, characterized in that: A lock nut (502) is threadedly connected to the top screw (5), and the lock nut (502) is tightly pressed against the outer wall of the adapter plate (4); the inner end of the top screw (5) is arranged as a ball head (501), and the ball head (501) contacts the outer side wall of the bottom of the top cover (1).

8. The negative pressure dust removal device according to claim 6, characterized in that: It also comprises a sealing tape (7), wherein the sealing tape (7) seals the gap between the top edge of the adapter plate (4) and the side wall of the top cover (1), and the sealing tape (7) covers the hinge (3).

9. The negative pressure dust removal device according to claim 8, characterized in that: The sealing belt (7) is specifically made of a rubber plate, and two sides of the sealing belt (7) are connected to the top of the adapter plate (4) and the side wall of the top cover (1) respectively by rivets and pressure strips.

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