A permanent magnet coupler with built-in heat sink

Abstract

The invention discloses a built-in heat sink type permanent magnet coupler, comprising an induction rotor assembly, a permanent magnet rotor assembly and a fan blade assembly for increasing the gas flow between the induction rotor assembly and the permanent magnet rotor assembly, the induction rotor assembly is cylindrical as a whole, the permanent magnet rotor assembly is disc-shaped as a whole, the permanent magnet rotor assembly is installed inside the induction rotor assembly, a radial air cavity is provided between the end face of the permanent magnet rotor assembly and the end face of the bottom of the cylinder of the induction rotor assembly, and an axial air gap is provided between the circumferential surface of the permanent magnet rotor assembly and the annular surface of the inner cylinder wall of the induction rotor assembly. Advantages: after the permanent magnet coupler is started, gas enters from the first air inlet and the second air inlet, and is discharged from the air outlet and the axial air gap, and the fan blade assembly in the radial air cavity forms a negative pressure inside the radial air cavity under the action of centrifugal force, accelerates the gas flow in the radial air cavity, and reduces the temperature of the equipment; the fan blade assembly is designed inside the permanent magnet coupler to effectively reduce the equipment noise.

Description

Technical Field

[0001] The invention relates to a coupler, in particular to a permanent magnet coupler with a built-in heat sink. Background Art

[0002] In the metallurgical, chemical, electric power, cement, water and mechanical industries, there are a large number of motor-driven coal mills, crushers, belt conveyors, fans, pumps and other mechanical devices. These existing devices are generally connected to the load and the motor through mechanical couplings such as elastic pin couplings, diaphragm couplings and steel ball couplings. Most systems have problems such as large starting torque, large vibration and high energy consumption.

[0003] In order to solve the problem of large starting torque, some devices also use hydraulic couplings and special soft starters instead of couplings to connect the load and the motor to reduce the starting torque, but the hydraulic coupling has problems such as low efficiency, oil leakage and large space occupation.

[0004] In order to solve the problem of hydraulic coupling, a permanent magnetic coupling is proposed. The permanent magnetic coupling structure consists of two parts: an induction rotor assembly and a permanent magnetic rotor assembly. It has a simple structure and can achieve constant speed transmission. However, according to the current load power requirements, the size of the permanent magnetic coupling will be very large, and the equipment of the permanent magnetic coupling will generate heat, which will affect the utilization rate of the equipment. Summary of the invention

[0005] The technical problem to be solved by the present invention is, in view of the shortcomings of the above-mentioned prior art, a permanent magnet coupler with a built-in heat sink is proposed. After the equipment is started, the added heat sink can enable the induction rotor assembly and the permanent magnet rotor assembly of the equipment to directly form a negative pressure inside the radial air cavity, thereby accelerating the gas flow and reducing the temperature of the equipment.

[0006] The technical solution adopted is: a built-in heat sink type permanent magnet coupler, including an induction rotor assembly, a permanent magnet rotor assembly and a fan blade assembly for increasing the gas flow between the induction rotor assembly and the permanent magnet rotor assembly, the induction rotor assembly and the permanent magnet rotor assembly are assembled in cooperation, and the fan blade assembly is arranged on the induction rotor assembly;

[0007] The induction rotor assembly is cylindrical in shape as a whole, the permanent magnet rotor assembly is disc-shaped as a whole, the permanent magnet rotor assembly is installed inside the induction rotor assembly, a radial air cavity is provided between the end surface of the permanent magnet rotor assembly and the end surface of the cylinder bottom of the induction rotor assembly, and an axial air gap is provided between the circumferential surface of the permanent magnet rotor assembly and the annular surface of the inner cylinder wall of the induction rotor assembly;

[0008] The fan blade assembly is mounted on the bottom of the induction rotor assembly, and the fan blade assembly is located in the radial air cavity;

[0009] The cylindrical induction rotor assembly is provided with a plurality of axial first air inlets and a plurality of radial air outlets, and the disc-shaped permanent magnet rotor assembly is provided with a plurality of axial second air inlets. The first air inlet, the second air inlet and the air outlet are all communicated with the radial air cavity, and the first air inlet, the second air inlet, the air outlet and the axial air gap constitute an internal air flow channel of the equipment.

[0010] The built-in heat sink type permanent magnet coupler of the technical solution of the present invention, after the permanent magnet coupler is started, the gas enters from the first air inlet and the second air inlet, and is discharged from the air outlet and the axial air gap. The fan blade assembly in the radial air cavity forms a negative pressure inside the radial air cavity under the action of centrifugal force, accelerates the gas flow in the radial air cavity, and reduces the temperature of the equipment.

[0011] The technical solution further defined in the present invention is:

[0012] The permanent magnet rotor assembly includes a magnetic base, a plurality of permanent magnets, a fixed plate corresponding to the permanent magnets to prevent the permanent magnets from being disengaged under the action of centrifugal force, a left sealing plate and a right sealing plate; a circle of permanent magnet slots for installing permanent magnets is arranged on the outer circumference of the magnetic base, the cross section of the permanent magnet slot is "∟", a plurality of permanent magnets are sequentially loaded into the permanent magnet slots, the permanent magnets fit the bottom of the permanent magnet slots, the fixed plate is "U" shaped, the fixed plate covers the permanent magnet slots, a permanent magnet is fixed in each fixed plate, and the gaps between the fixed plates and between the fixed plates and the permanent magnets are filled with sealant; the left sealing plate and the right sealing plate are both annular and are respectively arranged on the left and right end surfaces of the magnetic base; the second air inlet is opened on the body of the magnetic base, and all the second air inlets are located on the same circumference. The structural design of the permanent magnet rotor assembly in the present invention adopts a left sealing plate and a right sealing plate to make the whole symmetric, the design of the magnetic base takes into account the rapid disassembly and assembly of the permanent magnet, and the design of the fixed plate fully seals the permanent magnet.

[0013] The permanent magnet rotor assembly also includes magnetizing plates and circumferential sealing plates, which are equal in number to the number of permanent magnets. The circumferential sealing plates are sleeved on the outer circumferential surface of the magnetic base to seal all fixed plates, and the gap between the circumferential sealing plates and the fixed plates is filled with sealant; the magnetizing plates are arranged between the permanent magnets and the slot walls of the permanent magnet slots. The design of the magnetizing plates increases the magnetic field of the permanent magnets, and the circumferential sealing plates improve the overall appearance performance of the equipment.

[0014] The fixed plate, the magnetizing plate and the circumferential sealing plate are all made of non-magnetic conductive materials, and the magnetic base, the left sealing plate and the right sealing plate are made of magnetic conductive materials.

[0015] The induction rotor assembly includes an annular magnetic ring and a cylindrical conductor cylinder with an open end and a bottom at the other end. The magnetic ring is embedded in the conductor cylinder and fixed on the cylinder wall of the conductor cylinder. The first air inlet is opened on the cylinder bottom of the conductor cylinder. All the first air inlets are located on the same circumference. The circle where all the first air inlets are located has the same diameter as the circle where all the second air inlets are located. The first air inlet is arranged in a one-to-one correspondence with the second air inlet and the first air inlet is coaxially arranged with the second air inlet; the air outlet is opened on the cylinder wall of the conductor cylinder. The air outlet is arranged in a one-to-one correspondence with the first air inlet, and the air outlet is perpendicular to the axis of the corresponding first air inlet.

[0016] The conductor cylinder is made of magnetic material. An annular positioning convex ring for limiting the axial installation position of the magnetic ring is arranged on the inner cylinder wall of the conductor cylinder. The air outlet is located on the cylinder wall between the annular positioning convex ring and the bottom of the conductor cylinder.

[0017] The magnetic conductive ring is made of heat-conducting and electrically-conductive materials, and is fixed on the inner cylinder wall of the conductor cylinder by countersunk bolts.

[0018] The fan blade assembly is composed of a plurality of heat dissipation aluminum fins, all of which are arranged in a ring shape on the bottom of the conductor tube, and the second air inlets are evenly distributed on the bottom of the conductor tube between the heat dissipation aluminum fins.

[0019] The first air inlet, the second air inlet and the air outlet are all circular holes, the diameter of the air outlet is smaller than the diameters of the first air inlet and the second air inlet; the central axis of the air outlet is perpendicular to the central axis of the first air inlet.

[0020] The heat dissipation aluminum sheet is detachably arranged on the cylinder bottom of the conductor cylinder through a bolt and nut pair.

[0021] The beneficial effects of the present invention compared with the prior art are:

[0022] 1. In the built-in heat sink type permanent magnet coupler of the present invention, after the permanent magnet coupler is started, the gas enters from the first air inlet and the second air inlet, and is discharged from the air outlet and the axial air gap. The fan blade assembly in the radial air cavity forms a negative pressure inside the radial air cavity under the action of centrifugal force, thereby accelerating the gas flow in the radial air cavity and reducing the temperature of the equipment.

[0023] 2. The built-in heat sink type permanent magnetic coupler of the present invention has a fan blade assembly designed inside the permanent magnetic coupler, which effectively reduces equipment noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a cross-sectional view of the present invention.

[0025] Figure 2 for Figure 1 Zoom in on point A in the figure.

[0026] Figure 3This is the assembly drawing of the induction rotor assembly and the fan blade assembly.

[0027] Figure 4 Schematic diagram of the internal airflow channel of the device of Example 1.

[0028] Figure 5 This is a schematic diagram of an application example of Example 1. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is described in detail below, but the protection scope of the present invention is not limited to the embodiments.

[0030] To make the content of the present invention more clearly understood, the following Figure 1-Figure 5 The specific implementation manner is further described.

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1

[0032] The present embodiment 1 provides a built-in heat sink type permanent magnet coupler, comprising an induction rotor assembly 1, a permanent magnet rotor assembly 2 and a fan blade assembly 3 for increasing the gas flow between the induction rotor assembly 1 and the permanent magnet rotor assembly 2. The induction rotor assembly 1 is assembled with the permanent magnet rotor assembly 2, and the fan blade assembly 3 is arranged on the induction rotor assembly 1.

[0033] like Figure 1 and 4 As shown, the induction rotor assembly 1 is cylindrical as a whole, the permanent magnet rotor assembly 2 is disc-shaped as a whole, the permanent magnet rotor assembly 2 is installed in the induction rotor assembly 1, a radial air cavity 4 is provided between the end face of the permanent magnet rotor assembly 2 and the end face of the bottom of the induction rotor assembly 1, and an axial air gap 5 is provided between the circumferential surface of the permanent magnet rotor assembly 2 and the annular surface of the inner wall of the induction rotor assembly 1; the fan blade assembly 3 is installed on the bottom of the induction rotor assembly 1, and the fan blade assembly 3 is located in the radial air cavity 4; the fan blade assembly is designed inside the permanent magnet coupler to effectively reduce equipment noise.

[0034] like Figure 4 As shown, the cylindrical induction rotor assembly 1 is provided with a plurality of axial first air inlets 13 and a plurality of radial air outlets 14, and the disc-shaped permanent magnet rotor assembly 2 is provided with a plurality of axial second air inlets 29. The first air inlet 13, the second air inlet 29 and the air outlet 14 are all communicated with the radial air cavity 4, and the first air inlet 13, the second air inlet 29, the air outlet 14 and the axial air gap 5 constitute an internal air flow channel of the equipment.

[0035] After the permanent magnet coupler is started, the gas enters from the first air inlet and the second air inlet, and is discharged from the air outlet and the axial air gap. The fan blade assembly in the radial air cavity forms a negative pressure inside the radial air cavity under the action of centrifugal force, which accelerates the gas flow in the radial air cavity and reduces the temperature of the equipment.

[0036] The permanent magnet rotor assembly 2 includes a magnetic base 21, a plurality of permanent magnets 22, a fixed plate 24, a left sealing plate 25 and a right sealing plate 26 corresponding to the permanent magnets 22 to prevent the permanent magnets 22 from being disengaged under the action of centrifugal force; a circle of permanent magnet slots 28 for mounting the permanent magnets 22 is arranged on the outer peripheral edge of the magnetic base 21, and the cross section of the permanent magnet slots 28 is "∟", and the plurality of permanent magnets 22 are sequentially installed in the permanent magnet slots 28, and the permanent magnets 22 fit the bottom of the permanent magnet slots 28, The fixed plate 24 is "U"-shaped, and the fixed plate 24 covers the permanent magnet groove 28. A permanent magnet 22 is fixed in each fixed plate 24, and the gaps between the fixed plates 24 and between the fixed plates 24 and the permanent magnets 22 are filled with sealant; the left sealing plate 25 and the right sealing plate 26 are both annular and are respectively arranged on the left and right end surfaces of the magnetic base 21; the second air inlet 29 is opened on the body of the magnetic base 21, and all the second air inlets 29 are located on the same circumference.

[0037] like Figure 2 As shown, the permanent magnet rotor assembly 2 includes a magnetic base 21, a plurality of permanent magnets 22, a fixed plate 24 corresponding to the permanent magnets 22 to prevent the permanent magnets 22 from being disengaged under the action of centrifugal force, a left sealing plate 25, a right sealing plate 26, a magnetizing plate 23 and a circumferential sealing plate 27 equal in number to the permanent magnets 22; a circle of permanent magnet slots 28 for mounting the permanent magnets 22 is arranged along the outer circumference of the magnetic base 21, and the cross section of the permanent magnet slots 28 is "∟", and the plurality of permanent magnets 22 are sequentially installed in the permanent magnet slots 28, and the permanent magnets 22 are arranged on the outer circumference of the magnetic base 21. The body 22 fits the bottom of the permanent magnet slot 28, the fixed plate 24 is "U" shaped, the fixed plate 24 covers the permanent magnet slot 28, a permanent magnet 22 is fixed in each fixed plate 24, and the gaps between the fixed plates 24 and between the fixed plates 24 and the permanent magnet 22 are filled with sealant; the left sealing plate 25 and the right sealing plate 26 are both annular and are respectively arranged on the left and right end surfaces of the magnetic base 21; the second air inlet 29 is opened on the body of the magnetic base 21, and all the second air inlets 29 are located on the same circumference. The circumferential sealing plate 27 is sleeved on the outer circumference of the magnetic base 21 to seal all the fixed plates 24, and the gap between the circumferential sealing plate 27 and the fixed plate 24 is filled with sealant; the magnetizing plate 23 is arranged between the permanent magnet 22 and the slot wall of the permanent magnet slot 28.

[0038] The fixed plate 24, the magnetizing plate 23 and the circumferential sealing plate 27 are all made of non-magnetic materials, and in this embodiment, stainless steel plates are preferably used. The magnetic base 21, the left sealing plate 25 and the right sealing plate 26 are made of magnetic materials, and in this embodiment, steel plates are preferably used.

[0039] A central circular hole is provided at the center of the magnetic base 21 in the permanent magnet rotor assembly 2 for connection.

[0040] like Figure 3 As shown, the induction rotor assembly 1 includes an annular magnetic ring 12 and a cylindrical conductor cylinder 11 with an open end and a bottom at the other end. The magnetic ring 12 is embedded in the conductor cylinder 11 and fixed on the cylinder wall of the conductor cylinder 11. The first air inlet 13 is opened on the cylinder bottom of the conductor cylinder 11. All the first air inlets 13 are located on the same circumference. The circle where all the first air inlets 13 are located has the same diameter as the circle where all the second air inlets 29 are located. The first air inlets 13 are arranged one-to-one with the second air inlets 29 and the first air inlets 13 are arranged coaxially with the second air inlets 29; the air outlet 14 is opened on the cylinder wall of the conductor cylinder 11. The air outlet 14 is arranged one-to-one with the first air inlet 13, and the air outlet 14 is perpendicular to the axis of the corresponding first air inlet 13.

[0041] like Figure 3 As shown, the first air inlet 13 , the second air inlet 29 and the air outlet 14 are all circular holes, and the diameter of the air outlet 14 is smaller than the diameters of the first air inlet 13 and the second air inlet 29 ; the central axis of the air outlet 14 is perpendicular to the central axis of the first air inlet 13 .

[0042] The conductor tube 11 is made of magnetic conductive material, and in this embodiment, it is preferably made of steel plate. An annular positioning protrusion 15 is provided on the inner tube wall of the conductor tube 11 for limiting the axial installation position of the magnetic conductive ring 12, and the air outlet 14 is located on the tube wall between the annular positioning protrusion 15 and the bottom of the conductor tube 11. The magnetic conductive ring 12 is made of thermal conductive and conductive material, and in this embodiment, it is preferably made of copper plate or aluminum plate with good thermal and conductive properties. The magnetic conductive ring 12 is fixed to the inner tube wall of the conductor tube 11 with countersunk bolts.

[0043] A central circular hole is provided at the center of the bottom of the conductor cylinder 11 in the induction rotor assembly 1 for connection.

[0044] like Figure 3 As shown, the fan blade assembly 3 is composed of a plurality of heat dissipation aluminum fins 31, all of which are arranged in a ring shape on the bottom of the conductor cylinder 11, and the second air inlet 29 is evenly distributed on the bottom of the conductor cylinder 11 between the heat dissipation aluminum fins 31. The heat dissipation aluminum fins 31 are detachably arranged on the bottom of the conductor cylinder 11 by a bolt and nut pair.

[0045] like Figure 5 As shown, the working process of this embodiment is:

[0046] The induction rotor assembly 1 is connected to the motor 6, and the permanent magnet rotor assembly 2 is connected to the load 7. Among them, the center of the bottom of the conductor cylinder 11 in the induction rotor assembly 1 is provided with a central circular hole, which is installed on the output shaft of the motor through the motor end expansion sleeve, and rotates synchronously with the motor. The center of the magnetic base 21 in the permanent magnet rotor assembly 2 is provided with a central circular hole, which is installed on the input shaft of the load through the load end expansion sleeve 3, and rotates synchronously with the load. Both the induction rotor assembly 1 and the permanent magnet rotor assembly 2 are connected to the motor and the load respectively by expansion sleeves, which are convenient for installation, disassembly and maintenance.

[0047] There is a certain gap between the induction rotor assembly 1 and the permanent magnet rotor assembly 2, and the two can rotate with a certain slip, and the torque is transmitted through the induced current and induced magnetic field generated by the slip.

[0048] After the permanent magnet coupler is started, the gas enters from the first air inlet and the second air inlet, and is discharged from the air outlet and the axial air gap. The fan blade assembly in the radial air cavity forms a negative pressure inside the radial air cavity under the action of centrifugal force, which accelerates the gas flow in the radial air cavity and reduces the temperature of the equipment.

[0049] The above embodiments are only for illustrating the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention.

Claims

1. A permanent magnetic coupler with a built-in heat sink, characterized in that: The invention comprises an induction rotor assembly (1), a permanent magnet rotor assembly (2), and a fan blade assembly (3) for increasing the gas flow between the induction rotor assembly (1) and the permanent magnet rotor assembly (2); the induction rotor assembly (1) and the permanent magnet rotor assembly (2) are assembled in cooperation, and the fan blade assembly (3) is arranged on the induction rotor assembly (1); The induction rotor assembly (1) is cylindrical in shape as a whole, the permanent magnet rotor assembly (2) is disc-shaped as a whole, the permanent magnet rotor assembly (2) is installed inside the induction rotor assembly (1), a radial air cavity (4) is provided between the end surface of the permanent magnet rotor assembly (2) and the end surface of the cylinder bottom of the induction rotor assembly (1), and an axial air gap (5) is provided between the circumferential surface of the permanent magnet rotor assembly (2) and the annular surface of the inner cylinder wall of the induction rotor assembly (1); The fan blade assembly (3) is mounted on the bottom of the induction rotor assembly (1), and the fan blade assembly (3) is located in the radial air cavity (4); The cylindrical induction rotor assembly (1) is provided with a plurality of axial first air inlets (13) and a plurality of radial air outlets (14); the disc-shaped permanent magnet rotor assembly (2) is provided with a plurality of axial second air inlets (29); the first air inlets (13), the second air inlets (29) and the air outlets (14) are all in communication with the radial air cavity (4); the first air inlets (13), the second air inlets (29), the air outlets (14) and the axial air gap (5) constitute an air flow channel inside the device; The permanent magnet rotor assembly (2) comprises a magnetic base (21), a plurality of permanent magnets (22), a fixed plate (24) corresponding to the permanent magnets (22) to prevent the permanent magnets (22) from being disengaged under the action of centrifugal force, a left sealing plate (25) and a right sealing plate (26); a circle of permanent magnet slots (28) for mounting the permanent magnets (22) are arranged on the outer peripheral edge of the magnetic base (21); the cross section of the permanent magnet slots (28) is in the shape of a "∟", and the plurality of permanent magnets (22) are sequentially installed in the permanent magnet slots (28) Inside, the permanent magnet (22) fits the bottom of the permanent magnet slot (28), the fixed plate (24) is "U"-shaped, the fixed plate (24) covers the permanent magnet slot (28), a permanent magnet (22) is fixed in each fixed plate (24), and the gaps between the fixed plates (24) and between the fixed plates (24) and the permanent magnets (22) are filled with sealant; the left sealing plate (25) and the right sealing plate (26) are both annular and are respectively arranged on the left and right end surfaces of the magnetic base (21); The second air inlets (29) are provided on the body of the magnetic base (21), and all the second air inlets (29) are located on the same circumference; The induction rotor assembly (1) comprises an annular magnetic conductive ring (12) and a cylindrical conductor cylinder (11) with an opening at one end and a bottom at the other end, the magnetic conductive ring (12) being embedded in the conductor cylinder (11) and fixed on the cylinder wall of the conductor cylinder (11), the first air inlet (13) being provided on the cylinder bottom of the conductor cylinder (11), all the first air inlets (13) being located on the same circumference, the circle where all the first air inlets (13) are located having the same diameter as the circle where all the second air inlets (29) are located, the first air inlets (13) and the second air inlets (29) being arranged in a one-to-one correspondence and the first air inlets (13) and the second air inlets (29) being arranged coaxially; The air outlet (14) is provided on the wall of the conductor tube (11), the air outlet (14) and the first air inlet (13) are arranged in one-to-one correspondence, and the axis of the air outlet (14) and the corresponding first air inlet (13) are perpendicular; The fan blade assembly (3) is composed of a plurality of heat dissipation aluminum sheets (31), all of which are arranged in a ring shape on the bottom of the conductor cylinder (11), and the second air inlets (29) are evenly distributed on the bottom of the conductor cylinder (11) between the heat dissipation aluminum sheets (31).

2. The internal heat sink type permanent magnet coupler according to claim 1, characterized in that: The permanent magnet rotor assembly (2) further comprises magnetizing plates (23) and circumferential sealing plates (27) in the same number as the permanent magnets (22); the circumferential sealing plates (27) are sleeved on the outer circumferential surface of the magnetic base (21) to seal all the fixed plates (24); the gap between the circumferential sealing plates (27) and the fixed plates (24) is filled with sealing glue; the magnetizing plates (23) are arranged between the permanent magnets (22) and the slot walls of the permanent magnet slots (28).

3. The internal heat sink type permanent magnet coupler according to claim 2, characterized in that: The fixed plate (24), the magnetizing plate (23) and the circumferential sealing plate (27) are all made of non-magnetic conductive materials, and the magnetic base (21), the left sealing plate (25) and the right sealing plate (26) are made of magnetic conductive materials.

4. The internal heat sink type permanent magnet coupler according to claim 1, characterized in that: The conductor cylinder (11) is made of a magnetically conductive material. An annular positioning protrusion (15) for limiting the axial installation position of the magnetically conductive ring (12) is provided on the inner cylinder wall of the conductor cylinder (11). The air outlet (14) is located on the cylinder wall between the annular positioning protrusion (15) and the bottom of the conductor cylinder (11).

5. The internal heat sink type permanent magnet coupler according to claim 4, characterized in that: The magnetic conductive ring (12) is made of heat-conducting and electrically-conducting materials; the magnetic conductive ring (12) is fixed to the inner cylinder wall of the conductor cylinder (11) by countersunk bolts.

6. The internal heat sink type permanent magnet coupler according to claim 1, characterized in that: The first air inlet (13), the second air inlet (29) and the air outlet (14) are all circular holes, and the diameter of the air outlet (14) is smaller than the diameters of the first air inlet (13) and the second air inlet (29).

7. The internal heat sink type permanent magnet coupler according to claim 1, characterized in that: The heat dissipation aluminum sheet (31) is detachably arranged on the bottom of the conductor cylinder (11) by means of a bolt and nut pair.

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