A gas-fired air preheater

Abstract

The present invention discloses a gas-fired air preheater, and relates to the technical field of air preheaters. The present invention comprises a shell, and also comprises: a preheating part, the preheating part is used to preheat the air entering the boiler, the preheating part comprises a rotating shaft rotatably connected to the shell, and a fixed sleeve is fixedly installed on the rotating shaft, two filter plates are fixedly installed on the fixed sleeve, and a mounting ring is fixedly installed between the two filter plates; and a dust cleaning part, the dust cleaning part comprises a fixed ring fixedly installed on the shell. The advantage is that the present invention can automatically adjust the installation angle of the left heat exchange plate and the right heat exchange plate during the heat exchange process, and will not affect the flue gas emission under the premise of increasing the heat exchange surface area and the heat exchange time, and can also automatically clean the filter plate, the left heat exchange plate and the right heat exchange plate during the heat exchange process, reduce the attachment speed of smoke on them, and effectively improve the overall heat exchange efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of air preheaters, and in particular to a gas-fired air preheater. Background Art

[0002] A gas-fired air preheater is a device used to preheat the air required for boiler combustion. It uses gas as a heat source to heat the air. It plays an important role in improving the thermal efficiency of boiler systems and reducing environmental impacts. It is one of the common energy-saving and environmentally friendly equipment in modern industrial production and is often used in industrial boiler systems that require high efficiency and lower emissions.

[0003] The positions of the heat exchange fins on the existing gas-fired air preheaters are fixed. The heat transfer surface area remains unchanged during heat exchange treatment, and the flue gas flow rate remains unchanged, resulting in a shorter contact time between the flue gas and the heat exchange fins and poor overall heat exchange efficiency. If the heat transfer surface area and the contact time between the flue gas and the heat exchange fins are increased by changing the angle of the heat exchange fins, the flue gas will not be discharged smoothly and there will be more residues that affect the subsequent heat exchange effect. Therefore, it is necessary to design a gas-fired air preheater. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a gas-fired air preheater, which solves the problem of poor overall heat exchange efficiency mentioned in the above background technology.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A gas-fired air preheater comprises a housing and further comprises:

[0007] A preheating part, the preheating part is used to preheat the air entering the boiler, the preheating part comprises a rotating shaft rotatably connected to the shell, and a fixing sleeve is fixedly installed on the rotating shaft, two filter plates are fixedly installed on the fixing sleeve, and a mounting ring is fixedly installed between the two filter plates, and a plurality of left heat exchange fins and a plurality of right heat exchange fins are installed inside the mounting ring through a plurality of guide components;

[0008] The ash cleaning part includes a fixing ring fixedly mounted on the shell.

[0009] Furthermore, a rotating groove cooperating with the rotating shaft is provided on the outer shell, a rotating cavity cooperating with the mounting ring is provided in the outer shell, and the upper and lower side walls of the rotating cavity are interconnected with the rotating groove, a smoke port and an air port are provided on the outer shell, and the smoke port and the air port are interconnected with the rotating cavity.

[0010] Furthermore, sealing rings are fixedly mounted on the two filter plates, sealing cavities are opened on the upper and lower side walls of the rotating cavity, and the two sealing cavities are matched with the two sealing rings respectively.

[0011] Furthermore, two through grooves are provided on the upper and lower side walls of the shell, and two mounting plates are fixedly installed on the upper and lower side walls of the shell by multiple bolts, and a cleaning plate is fixedly installed on one end of each mounting plate located in the corresponding through groove, and each of the cleaning plates is respectively matched with the corresponding filter plate.

[0012] Furthermore, the guide assembly includes a rotating rod fixedly connected to the left heat exchanger plate, the mounting ring is provided with a rotating hole matching the rotating rod, and a fixed gear is fixedly installed on one end of the rotating rod located outside the mounting ring. The multiple left heat exchanger plates and the multiple right heat exchanger plates are staggered up and down, and the rotating rod is fixedly connected to the right side of the left heat exchanger plate, and the rotating rod is fixedly connected to the left side of the right heat exchanger plate, and the multiple fixed gears located on the same vertical plane are meshed with each other.

[0013] Furthermore, an annular groove is provided on the side wall of the rotating chamber, and a plurality of fixed racks are fixedly installed on the top of the annular groove, and the plurality of fixed racks cooperate with a plurality of fixed gears located at the upper end.

[0014] Furthermore, a fixing plate is fixedly mounted on one end of the rotating rod outside the mounting ring, and a return torsion spring is installed between the fixing plate and the mounting ring.

[0015] Furthermore, a through hole is provided on the filter plate at the lower end, and the diameter of the through hole is larger than the diameter of the fixed sleeve. The through hole is connected to the fixed ring in a rotating seal, and an internal ring is fixedly installed at one end of the fixed ring located inside the mounting ring, and a plurality of cleaning rods are fixedly installed on the side wall of the internal ring, and the plurality of cleaning rods cooperate with a plurality of left-side heat exchange plates and a plurality of right-side heat exchange plates.

[0016] Furthermore, a support ring is fixedly installed on the top of the rotating chamber, and the support ring is rotatably connected to the top of the fixed sleeve.

[0017] Furthermore, the arc length of the fixed rack is less than one quarter of the circumference of the fixed gear, and the minimum arc length of adjacent fixed racks is greater than one quarter of the circumference of the fixed gear.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1: Through the design of the guide assembly and the reset torsion spring, the left heat exchanger and the right heat exchanger can be continuously switched between the horizontal state and the corrugated state by rotating the mounting ring during the heat exchange process. At this time, the heat exchange surface area and heat exchange time with the flue gas and air will be increased, thereby effectively improving the heat exchange efficiency.

[0020] 2: Through the coordination of the fixed gear and the fixed rack and the size limitation, the angle change position of the left heat exchanger and the right heat exchanger can be controlled, so that it can improve the overall heat exchange efficiency without affecting the flue gas emission, ensuring the overall efficient heat exchange.

[0021] 3: Through the design of the cleaning part and the cleaning plate, the filter plate, the left heat exchange plate and the right heat exchange plate can be automatically cleaned during the heat exchange process, reducing the adhesion speed of smoke and dust on them, which can further improve the overall heat exchange effect of the preheater.

[0022] In summary, the present invention can automatically adjust the installation angles of the left heat exchanger fin and the right heat exchanger fin during the heat exchange process, without affecting the flue gas emissions under the premise of increasing the heat exchange surface area and the heat exchange time. In addition, the filter plate, the left heat exchanger fin and the right heat exchanger fin can be automatically cleaned during the heat exchange process to reduce the adhesion speed of smoke and dust thereon, thereby effectively improving the overall heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a gas-fired air preheater proposed by the present invention;

[0024] Figure 2 for Figure 1 A schematic diagram of the structure of the middle housing and its connecting components after being deflected by a certain angle;

[0025] Figure 3 for Figure 2 A top view of

[0026] Figure 4 for Figure 3 The structural diagram of the middle A surface;

[0027] Figure 5 for Figure 4 Schematic diagram of the three-dimensional structure;

[0028] Figure 6 for Figure 5 A schematic diagram of the structure of part a in the middle is enlarged;

[0029] Figure 7 for Figure 1 Schematic diagram of the internal structure of the middle shell;

[0030] Figure 8 for Figure 7 A schematic diagram of the structure of the middle mounting ring and its components;

[0031] Fig. 9 for Figure 8 Schematic diagram of the structure after being deflected upwards by a certain angle;

[0032] Fig.10 for Figure 7Schematic diagram of the internal structure of the middle mounting ring;

[0033] Fig.11 for Fig.10 Schematic diagram of the structure after being deflected upwards by a certain angle;

[0034] Fig.12 for Fig.10 An enlarged schematic diagram of the structure of multiple fixed gears and their connecting components;

[0035] Fig.13 for Fig.12 Schematic diagram of the structure after deflection at a certain angle.

[0036] In the figure: 1. outer shell; 2. rotating shaft; 3. fixing sleeve; 4. filter plate; 5. mounting ring; 6. rotating chamber; 7. sealing ring; 8. sealing chamber; 9. flue gas outlet; 10. air outlet; 11. mounting plate; 12. cleaning plate; 13. rotating groove; 14. rotating hole; 15. rotating rod; 16. left heat exchange plate; 17. right heat exchange plate; 18. fixing gear; 19. fixing plate; 20. reset torsion spring; 21. annular groove; 22. fixing rack; 23. through hole; 24. supporting ring; 25. fixing ring; 26. built-in ring; 27. cleaning rod. DETAILED DESCRIPTION

[0037] Reference Figure 1-Figure 13 , a gas-fired air preheater, comprising a housing 1, and further comprising:

[0038] The preheating part is used to preheat the air entering the boiler. The preheating part includes a rotating shaft 2 rotatably connected to the outer shell 1, and a fixing sleeve 3 is fixedly installed on the rotating shaft 2, two filter plates 4 are fixedly installed on the fixing sleeve 3, and a mounting ring 5 is fixedly installed between the two filter plates 4. The fixed connection between the rotating shaft 2 and the fixing sleeve 3 can drive the mounting ring 5 to rotate in the outer shell 1 when the rotating shaft 2 rotates. A rotating groove 13 matching the rotating shaft 2 is provided on the outer shell 1, and a rotating chamber 6 matching the mounting ring 5 is provided in the outer shell 1, and the upper and lower side walls of the rotating chamber 6 are interconnected with the rotating groove 13. The design of the rotating chamber 6 can provide a rotating space for the rotation of the mounting ring 5 and limit the flow direction of the flue gas and air in the outer shell 1.

[0039] A smoke port 9 and an air port 10 are provided on the outer shell 1, and the smoke port 9 and the air port 10 are interconnected with the rotating chamber 6. The smoke port 9 is used to pass the high-temperature smoke into the outer shell 1 from top to bottom, and the air port 10 is used to pass the air into the outer shell 1 from bottom to top. When the high-temperature smoke is passed in, the smoke enters the mounting ring 5, and the heat therein is absorbed. Then the smoke that has lost the heat is discharged through the bottom of the smoke port 9. Afterwards, due to the rotation of the rotating shaft 2, the part of the mounting ring 5 that absorbs the heat of the smoke will rotate from the corresponding position of the smoke port 9 to the corresponding position of the air port 10. At this time, the air entering the mounting ring 5 from the air port 10 absorbs the heat in the mounting ring 5, and then the heated air enters the boiler through the top of the air port 10. With the continuous rotation of the rotating shaft 2 and the continuous circulation of smoke and air, an effective air preheating effect can be achieved.

[0040] Sealing rings 7 are fixedly installed on the two filter plates 4, and sealing chambers 8 are opened on the upper and lower side walls of the rotating chamber 6, and the two sealing chambers 8 are respectively matched with the two sealing rings 7. Through the cooperation of the sealing rings 7 and the sealing chambers 8, the flue gas and air entering the outer shell 1 can smoothly enter the installation ring 5 for heat exchange, and their flow direction is limited to prevent the flue gas and air from flowing into the installation ring 5 and the outer shell 1, thereby reducing heat loss.

[0041] A plurality of left heat exchange fins 16 and a plurality of right heat exchange fins 17 are installed inside the mounting ring 5 through a plurality of guide components. The guide component includes a rotating rod 15 fixedly connected to the left heat exchange fin 16. A rotating hole 14 matching the rotating rod 15 is provided on the mounting ring 5. A fixed gear 18 is fixedly installed at one end of the rotating rod 15 located outside the mounting ring 5. The plurality of left heat exchange fins 16 and the plurality of right heat exchange fins 17 are staggered up and down, and the rotating rod 15 is fixedly connected to the right side of the left heat exchange fin 16, and the rotating rod 15 is fixedly connected to the left side of the right heat exchange fin 17. The plurality of fixed gears 18 located on the same vertical plane mesh with each other. Through the position design of the multiple left-side heat exchanger fins 16 and the multiple right-side heat exchanger fins 17 and the design of the connection position with the corresponding rotating rod 15, when one of the multiple rotating rods 15 located on the same vertical plane rotates, the multiple left-side heat exchanger fins 16 can rotate to the same side and the multiple right-side heat exchanger fins 17 can rotate to the other side under the meshing action of the multiple fixed gears 18. When rotating, the upper and lower adjacent left-side heat exchanger fins 16 and right-side heat exchanger fins 17 change from the original horizontal state to a corrugated state. At this time, the heat exchange surface area and heat exchange time with the flue gas and air are increased, thereby effectively improving the heat exchange efficiency.

[0042] An annular groove 21 is provided on the side wall of the rotating chamber 6, and a plurality of fixed racks 22 are fixedly installed on the top of the annular groove 21. The plurality of fixed racks 22 cooperate with the plurality of fixed gears 18 located at the upper end. The annular groove 21 is used to provide corresponding moving space for the plurality of fixed gears 18 as the mounting ring 5 rotates. Through the design of the plurality of fixed racks 22, when the rotating shaft 2 rotates to drive the mounting ring 5 to rotate, the plurality of fixed gears 18 located at the uppermost end will mesh and rotate with the plurality of fixed racks 22 in turn. Therefore, the angles of the plurality of left-side heat exchange fins 16 and the plurality of right-side heat exchange fins 17 therein can be automatically regulated during the rotation of the mounting ring 5, so that the preheater can automatically adjust the installation angle of the heat exchange fins at the corresponding position according to the rotation of the mounting ring 5, so that the best heat transfer and heat exchange effect can be achieved at the corresponding position.

[0043] A fixing plate 19 is fixedly mounted on one end of the rotating rod 15 outside the mounting ring 5, and a reset torsion spring 20 is installed between the fixing plate 19 and the mounting ring 5. Through the cooperation of the fixing plate 19 and the reset torsion spring 20, when the fixed gear 18 is separated from the fixed rack 22, the rotating rod 15 can be automatically reset and rotated. Therefore, when the rotating rod 15 is not subjected to external force, it can ensure that the multiple left heat exchange fins 16 and the multiple right heat exchange fins 17 are in a horizontal state. The arc length of the fixed rack 22 is less than one-fourth of the circumference of the fixed gear 18. The advantage of the size design here is that the rotation angle of the fixed gear 18 driven by the fixed rack 22 can be controlled. To avoid the problem that the left heat exchanger fin 16 and the right heat exchanger fin 17 are deflected too much and the heat exchange effect is reduced or they are damaged by contact with each other, the minimum arc length of adjacent fixed racks 22 is greater than one-fourth of the circumference of the fixed gear 18. The advantage of the size design here is that when the fixed gear 18 is separated from the fixed rack 22, the fixed gear 18 has enough time to achieve rotational reset under the action of the reset torsion spring 20, thereby preparing for the next angular deflection, avoiding the problem that incomplete reset causes the left heat exchanger fin 16 and the right heat exchanger fin 17 to deflect at an angle exceeding the maximum limit after multiple angular deflections.

[0044] The minimum arc length between the fixed rack 22 located at the smoke outlet 9 and the fixed rack 22 located at the air outlet 10 is greater than the minimum arc length between the smoke outlet 9 and the air outlet 10. Through this design, the left heat exchange plate 16 and the right heat exchange plate 17 can be in a horizontal state before rotating into the position between the smoke outlet 9 and the air outlet 10, which makes it easy to discharge the smoke retained therein.

[0045] Two through grooves are provided on the upper and lower side walls of the shell 1. Two mounting plates 11 are fixedly installed on the upper and lower side walls of the shell 1 by multiple bolts, and a cleaning plate 12 is fixedly installed on one end of each mounting plate 11 located in the corresponding through groove. Each cleaning plate 12 is respectively matched with the corresponding filter plate 4. Through the design of multiple cleaning plates 12, the parts of the upper and lower filter plates 4 located between the flue gas port 9 and the air port 10 can be cleaned. Therefore, with the rotation of the rotating shaft 2, the upper and lower filter plates 4 can be continuously cleaned, reducing the possibility of dust in the flue gas accumulating thereon and causing blockage of the filter plate 4, thereby improving the overall heat exchange efficiency of the preheater. At the same time, the design of the mounting plate 11 can facilitate the replacement or cleaning of the cleaning plate 12 after a period of use, thereby ensuring its cleaning effect on the filter plate 4.

[0046] The ash cleaning part includes a fixing ring 25 fixedly mounted on the outer shell 1, a through hole 23 is opened on the filter plate 4 at the lower end, and the diameter of the through hole 23 is larger than the diameter of the fixing sleeve 3, the through hole 23 and the fixing ring 25 are connected in a rotating seal, and an inner ring 26 is fixedly mounted on one end of the fixing ring 25 located in the mounting ring 5, and a plurality of cleaning rods 27 are fixedly mounted on the side wall of the inner ring 26, and the plurality of cleaning rods 27 cooperate with a plurality of left heat exchanger fins 16 and a plurality of right heat exchanger fins 17, and the plurality of cleaning rods 27 are all located between the flue gas port 9 and the air port 10. When the left heat exchanger fin 16 and the right heat exchanger fin 17 rotate to enter between the flue gas port 9 and the air port 10, they will pass through the plurality of cleaning rods 27 as the mounting ring 5 rotates in a horizontal state. At this time, the plurality of cleaning rods 27 can be used to clean the left heat exchanger fin 16 and the right heat exchanger fin 17, thereby reducing the adhesion speed of smoke and dust thereon, improving the heat exchange effect, and further improving the overall heat exchange effect of the preheater.

[0047] A support ring 24 is fixedly installed on the top of the rotating chamber 6, and the support ring 24 is rotatably connected to the top of the fixed sleeve 3. Through the design of the support ring 24, the rotation of the mounting ring 5 in the outer shell 1 can be limited and the support function can be increased, so that the mounting ring 5 can rotate more stably in the rotating chamber 6 when the rotating shaft 2 rotates.

[0048] In the present invention, a working principle of a gas-fired air preheater includes the following steps:

[0049] Air preheating treatment: Use the existing flue gas duct and air duct to pass the flue gas into the flue gas port 9 and the air into the air port 10 respectively. The high-temperature flue gas passes into the housing 1 from top to bottom, and after entering the mounting ring 5, the heat is absorbed by the left heat exchanger fin 16 and the right heat exchanger fin 17 located at the corresponding position of the flue gas port 9, and then the flue gas is discharged through the flue gas port 9;

[0050] The air is passed into the shell 1 from bottom to top. Due to the rotation of the rotating shaft 2, the corresponding left heat exchanger fin 16 and right heat exchanger fin 17 in the mounting ring 5 that have absorbed the heat of the flue gas will rotate from the corresponding position of the flue gas port 9 to the corresponding position of the air port 10. At this time, the air entering the mounting ring 5 from the air port 10 absorbs the heat of the corresponding left heat exchanger fin 16 and right heat exchanger fin 17. Then, the heated air enters the boiler through the top of the air port 10. With the continuous rotation of the rotating shaft 2 and the continuous circulation of the flue gas and air, an effective air preheating effect can be achieved.

[0051] Increase of heat exchange surface area and heat exchange time: When the left heat exchange plate 16 and the right heat exchange plate 17 are located at the corresponding positions of the smoke outlet 9 or the air outlet 10, the corresponding fixed gear 18 will intermittently mesh and separate with the multiple fixed racks 22 as the mounting ring 5 rotates. In this process, through the meshing effect of the fixed gear 18 and the fixed rack 22 and the torsion effect of the reset torsion spring 20, the upper and lower adjacent left heat exchange plate 16 and right heat exchange plate 17 are transformed from the original horizontal state to the corrugated state, and continuously switch between the two states. At this time, the heat exchange surface area and heat exchange time with the smoke and air will be increased, so the heat exchange efficiency can be effectively improved;

[0052] Cleaning treatment: During the rotation of the shaft 2, the cleaning plate 12 can be used to continuously clean the upper and lower filter plates 4, thereby reducing the possibility of dust in the flue gas accumulating thereon and causing the filter plates 4 to be blocked, thereby improving the overall heat exchange efficiency of the preheater;

[0053] When the left heat exchanger fin 16 and the right heat exchanger fin 17 rotate into the position between the smoke outlet 9 and the air outlet 10, they will remain in a horizontal state and pass through multiple cleaning rods 27. At this time, the multiple cleaning rods 27 can be used to clean the left heat exchanger fin 16 and the right heat exchanger fin 17 to reduce the adhesion speed of smoke and dust thereon, improve the heat exchange effect, and further improve the overall heat exchange effect of the preheater.

[0054] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A gas-fired air preheater, comprising a housing (1), characterized in that: Also includes: A preheating part, the preheating part is used to preheat the air entering the boiler, the preheating part comprises a rotating shaft (2) rotatably connected to the outer shell (1), and a fixing sleeve (3) is fixedly mounted on the rotating shaft (2), two filter plates (4) are fixedly mounted on the fixing sleeve (3), and a mounting ring (5) is fixedly mounted between the two filter plates (4), and a plurality of left heat exchange fins (16) and a plurality of right heat exchange fins (17) are mounted inside the mounting ring (5) through a plurality of guide components; A dust cleaning section, the dust cleaning section comprising a fixing ring (25) fixedly mounted on the housing (1); The housing (1) is provided with a rotating chamber (6) matched with the mounting ring (5); the guide assembly comprises a rotating rod (15) fixedly connected to the left heat exchange plate (16); the mounting ring (5) is provided with a rotating hole (14) matched with the rotating rod (15); a fixed gear (18) is fixedly installed at one end of the rotating rod (15) located outside the mounting ring (5); a plurality of left heat exchange plates (16) and a plurality of right heat exchange plates (17) are arranged in an up-and-down staggered manner; the rotating rod (15) is fixedly connected to the right side of the left heat exchange plate (16); the rotating rod (15) is fixedly connected to the left side of the right heat exchange plate (17); and the plurality of fixed gears (18) located on the same vertical plane are meshed with each other; An annular groove (21) is provided on the side wall of the rotating chamber (6), and a plurality of fixed racks (22) are fixedly installed on the top of the annular groove (21), and the plurality of fixed racks (22) cooperate with a plurality of fixed gears (18) located at the upper end; A fixing plate (19) is fixedly mounted on one end of the rotating rod (15) outside the mounting ring (5), and a return torsion spring (20) is installed between the fixing plate (19) and the mounting ring (5); The arc length of the fixed rack (22) is less than one quarter of the circumference of the fixed gear (18), and the minimum arc length of adjacent fixed racks (22) is greater than one quarter of the circumference of the fixed gear (18).

2. A gas-fired air preheater according to claim 1, characterized in that: The outer shell (1) is provided with a rotation groove (13) matched with the rotation shaft (2), and the rotation groove (13) is communicated with the upper and lower side walls of the rotation chamber (6). The outer shell (1) is provided with a smoke port (9) and an air port (10), and the smoke port (9) and the air port (10) are communicated with the rotation chamber (6).

3. A gas-fired air preheater according to claim 1, characterized in that: A sealing ring (7) is fixedly mounted on each of the two filter plates (4), and a sealing cavity (8) is provided on both upper and lower side walls of the rotating cavity (6), and the two sealing cavities (8) are respectively matched with the two sealing rings (7).

4. A gas-fired air preheater according to claim 1, characterized in that: The upper and lower side walls of the shell (1) are each provided with two through slots, and two mounting plates (11) are fixedly mounted on the upper and lower side walls of the shell (1) by means of a plurality of bolts, and a dust cleaning plate (12) is fixedly mounted on one end of each mounting plate (11) located in the corresponding through slot, and each of the dust cleaning plates (12) is respectively matched with a corresponding filter plate (4).

5. A gas-fired air preheater according to claim 1, characterized in that: A through hole (23) is provided on the filter plate (4) at the lower end, and the diameter of the through hole (23) is larger than the diameter of the fixed sleeve (3). The through hole (23) is connected to the fixed ring (25) in a rotating seal, and an inner ring (26) is fixedly installed at one end of the fixed ring (25) located inside the mounting ring (5). A plurality of cleaning rods (27) are fixedly installed on the side wall of the inner ring (26), and the plurality of cleaning rods (27) cooperate with a plurality of left heat exchange plates (16) and a plurality of right heat exchange plates (17).

6. A gas-fired air preheater according to claim 1, characterized in that: A support ring (24) is fixedly mounted on the top of the rotating chamber (6), and the support ring (24) is rotatably connected to the top of the fixed sleeve (3).

Images