Mining explosion-proof direct-drive permanent magnet motor

Abstract

The invention belongs to the technical field of explosion prevention of permanent magnet motors, and particularly relates to a mining explosion-proof direct-drive permanent magnet motor, which comprises a permanent magnet motor, an output shaft and a base, an outer ring of the permanent magnet motor is fixedly provided with a gas ring, the periphery of the gas ring is uniformly provided with gas holes, and a driving cavity is fixed above the base; a notch is formed in the upper portion of the driving cavity, the driving cavity comprises a gear, a sleeve, an extrusion rod, an air pressure cavity, an air pressure plate, an air pressure rod, a filtering cavity, an air cavity and an air guide pipe, the permanent magnet motor is fixedly installed on the upper portion of the base, the output shaft is fixedly connected with the output end of the permanent magnet motor, and a fluted disc is fixed to the outer side of the output shaft; according to the explosion-proof permanent magnet motor, the problem that the safety of a coal mine is threatened due to the fact that a current permanent magnet motor is made of an explosion-proof material, sparks or high temperature can still be generated in the operation process, and the sparks and the high temperature can cause explosion is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of explosion-proof of permanent magnet motors, and in particular relates to an explosion-proof direct-drive permanent magnet motor for mining. Background Art

[0002] The main reason why permanent magnet motors for mining need explosion-proof is that there are flammable gases and dust in the coal mine environment, which can form explosive mixtures under certain conditions. The motor may generate sparks or high temperatures during operation, which may cause explosions and pose a threat to coal mine safety. The explosion-proof methods currently used in the market are:

[0003] 1. Structural explosion-proof design: There is a certain gap between the mating surfaces of the motor components. When sparks occur inside the motor or flames occur in the explosive mixture, the flames spread outward along the gaps of the joint surfaces, and most of the energy is blocked or consumed in the gaps. When the flames spread outside the casing, their energy and temperature are not enough to ignite the explosive mixture outside;

[0004] 2. Use of special materials: Use high temperature resistant and explosion-proof materials to ensure that the motor can still maintain stable operation in a high temperature environment and avoid sparks or high temperatures;

[0005] These can only provide basic explosion protection, and there will still be danger when the concentration of combustible gas in the mine is high. Therefore, in this case, attention should be paid to the oxygen concentration and the concentration of inert gas around the permanent magnet motor. This phenomenon has become a problem that needs to be solved urgently by people in this field. Summary of the invention

[0006] The object of the present invention is to provide an explosion-proof direct-drive permanent magnet motor for mining to solve the problems raised in the above background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: an explosion-proof direct-drive permanent magnet motor for mining, comprising a permanent magnet motor, an output shaft and a base, an outer ring of the permanent magnet motor is fixedly mounted with an air ring, air holes are evenly arranged around the air ring, and a driving cavity is fixed above the base; a notch is arranged above the driving cavity, and the driving cavity comprises a gear, a sleeve, an extrusion rod, an air pressure cavity, an air pressure plate, an air pressure rod, a filter cavity, an air cavity and an air guide tube, the permanent magnet motor is fixedly mounted above the base, and the output shaft is fixedly connected to the output end of the permanent magnet motor, A toothed disc is fixed on the outside; the toothed disc is located in the groove and meshes with the gear, the gear bearing is installed on the inner wall of the driving chamber, the sleeve is fixedly installed on one side of the gear, the extrusion rod is sleeved on the inside of the sleeve, the pneumatic chamber is fixedly installed on the right side of the inner wall of the driving chamber, the pneumatic plate is slidably connected to the inner wall of the pneumatic chamber, the pneumatic rod is fixedly installed on the left side of the pneumatic plate, and the extrusion rod and the pneumatic rod are in contact with each other after the gear rotates, both ends of the extrusion rod and the outer end of the pneumatic rod are spherical, and a reverse thrust spring is connected between the pneumatic plate and the right side of the inner wall of the pneumatic chamber.

[0008] The present invention further illustrates that the right side of the air pressure chamber is connected to an external pipeline, and a one-way valve 1 is arranged in the pipeline, the right side of the air pressure chamber is connected to a filter chamber pipeline, and a one-way valve 2 is arranged in the pipeline, and a carbon molecular sieve is arranged inside the filter chamber, the filter chamber is connected to the air chamber pipeline, and the air chamber is connected to the inside of the air ring through an air guide tube; a pressure valve 1 is arranged inside the air guide tube.

[0009] The present invention further illustrates that the relationship between the jet frequency of the air ring and the operating power of the permanent magnet motor is: HZ is the jet frequency of the air ring, HZ max is the maximum jet frequency of the gas ring, F is the operating power of the permanent magnet motor, F max is the maximum operating power of the permanent magnet motor.

[0010] The present invention further illustrates that the left side of the air pressure chamber is connected to an air intake pipe, and a one-way valve three is arranged inside the air intake pipe, the left side of the air pressure chamber is connected to an exhaust pipe, and a one-way valve four is arranged inside the exhaust pipe, and the inner diameter of the air intake pipe is twice the inner diameter of the exhaust pipe.

[0011] The present invention further illustrates that a fluctuation chamber is fixed at the bottom of the inner wall of the driving chamber, and a fluctuation plate is slidably connected to the inner wall of the fluctuation chamber, and a fluctuation rod is fixed above the fluctuation plate, and the upper end of the fluctuation rod is spherical; a sliding hole is provided in the middle of the sleeve, and a pressing rod is slidably connected in the sliding hole, both ends of the pressing rod are spherical, and the inner end contacts one end of the extrusion rod, and the fluctuation rod contacts the outer end of the pressing rod after rising; a limit block is provided on the outer side of the extrusion rod, and a fixed block is provided on the inner wall of the sleeve, and a connecting spring is fixedly installed between the limit block and the fixed block; a conduit is connected between the left side of the air pressure chamber and the bottom of the fluctuation chamber, and a pressure valve 2 is provided inside the conduit, and the bottom of the fluctuation chamber is connected to the external control valve pipeline.

[0012] The present invention further describes that shock-absorbing cavities are fixed on both left and right sides of the bottom of the base, a sliding plate is slidably connected to the inner wall of the shock-absorbing cavity, a support rod is fixed to the bottom of the sliding plate, and a support seat is fixed to the bottom end of the support rod; a buffer spring is fixed between the top of the sliding plate and the top of the inner wall of the shock-absorbing cavity.

[0013] The present invention further describes that two holes are arranged on the surface of the sliding plate, a pipeline is connected between the upper part of the undulating cavity and the upper part of the shock-absorbing cavity, and the upper part of the undulating plate is filled with hydraulic oil.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention sprays nitrogen from the air holes of the air ring, and nitrogen is an inert gas, which can reduce the oxygen concentration near the permanent magnet motor and retain the inert gas, so that it can play an explosion-proof role when the permanent magnet motor generates electric sparks during operation. In addition to the permanent magnet motor made of explosion-proof materials, it can further avoid explosions, and the explosion-proof effect is greatly improved. The higher the operating power of the permanent magnet motor, the easier it is to generate sparks. At this time, the frequency of extracting gas from the air pressure chamber and injecting it into the air cavity is accelerated, so that the frequency of the air ring spraying nitrogen is accelerated, which is fully explosion-proof. On the contrary, the frequency of the air ring spraying nitrogen is reduced, which can not only prevent explosions but also avoid excessive wear of the structure, and at the same time relatively guarantee the service life of the carbon molecular sieve;

[0015] And when the operating power of the permanent magnet motor reaches the maximum, the extrusion rod moves to the right. At this time, when the air pressure chamber extracts gas and injects gas into the air cavity, the contact area between the extrusion rod and the air pressure rod increases, and the extrusion amplitude increases, thereby increasing the reciprocating stroke of the air pressure plate, and the frequency of nitrogen spraying from the air ring is further increased, which can further reduce the oxygen near the permanent magnet motor, thereby achieving a full explosion-proof effect and further improving safety performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 is a plan view of the driving cavity of the present invention;

[0019] Figure 3 It is a schematic diagram of the internal structure of the shock-absorbing cavity and the driving cavity of the present invention;

[0020] Figure 4 It is a schematic diagram of the internal structure of the air pressure chamber and the location of the pipeline of the present invention;

[0021] Figure 5 It is a schematic diagram of the internal structure of the heaving chamber and the positional relationship between the heaving rod and the sleeve of the present invention;

[0022] Figure 6 It is a schematic diagram of the internal structure of the sleeve of the present invention;

[0023] Figure 7 It is a schematic diagram of the air pressure chamber, the filter chamber and the pipe connection between the air chambers of the present invention;

[0024] Figure 8 It is a schematic diagram of the pipe connection between the air pressure chamber, the heave chamber and the shock-absorbing chamber of the present invention;

[0025] In the figure: 1. output shaft; 11. gear disc; 2. base; 3. air ring; 4. drive chamber; 41. gear; 42. sleeve; 421. extrusion rod; 422. pressing rod; 423. connecting spring; 43. air pressure chamber; 431. air pressure plate; 432. air pressure rod; 433. filter chamber; 434. air chamber; 435. air guide tube; 436. intake pipe; 437. exhaust pipe; 44. ups and downs chamber; 441. ups and downs plate; 442. ups and downs rod; 45. conduit; 5. shock-absorbing chamber; 51. sliding plate; 511. hole; 52. support rod; 53. support seat; 54. buffer spring. DETAILED DESCRIPTION

[0026] The following is a further non-limiting detailed description of the technical solution of the present invention in conjunction with the preferred embodiments and 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 creative work are within the scope of protection of the present invention.

[0027] See also Figure 1-8The present invention provides a technical solution: a mining explosion-proof direct-drive permanent magnet motor, comprising a permanent magnet motor, an output shaft 1 and a base 2, an outer ring of the permanent magnet motor is fixedly mounted with an air ring 3, air holes are evenly arranged around the air ring 3, and a driving cavity 4 is fixed above the base 2;

[0028] A notch is provided above the driving chamber 4, and the driving chamber 4 includes a gear 41, a sleeve 42, an extrusion rod 421, an air pressure chamber 43, an air pressure plate 431, an air pressure rod 432, a filter chamber 433, an air chamber 434 and an air guide tube 435. The permanent magnet motor is fixedly installed above the base 2, the output shaft 1 is fixedly connected to the output end of the permanent magnet motor, and a toothed disc 11 is fixed on the outside;

[0029] The toothed disc 11 is located in the slot and meshes with the gear 41. The bearing of the gear 41 is installed on the inner wall of the driving chamber 4. The sleeve 42 is fixedly installed on one side of the gear 41. The extrusion rod 421 is sleeved inside the sleeve 42. The pneumatic chamber 43 is fixedly installed on the right side of the inner wall of the driving chamber 4. The pneumatic plate 431 is slidably connected to the inner wall of the pneumatic chamber 43. The pneumatic rod 432 is fixedly installed on the left side of the pneumatic plate 431. After the gear 41 rotates, the extrusion rod 421 and the pneumatic rod 432 contact each other. Both ends of the extrusion rod 421 and the outer end of the pneumatic rod 432 are spherical. A reverse thrust spring is connected between the pneumatic plate 431 and the right side of the inner wall of the pneumatic chamber 43.

[0030] The right side of the air pressure chamber 43 is connected to the external pipeline, and a one-way valve 1 is arranged in the pipeline. The right side of the air pressure chamber 43 is connected to the filter chamber 433 pipeline, and a one-way valve 2 is arranged in the pipeline. A carbon molecular sieve is arranged inside the filter chamber 433. The filter chamber 433 is connected to the air chamber 434 pipeline, and the air chamber 434 is connected to the inside of the air ring 3 through the air guide pipe 435.

[0031] A pressure valve 1 is provided inside the air guide tube 435;

[0032] When the permanent magnet motor is running, it drives the output shaft 1 to rotate, and the output shaft 1 drives the gear 41 to rotate through the toothed disc 11, and the gear 41 drives the extrusion rod 421 to rotate around its center through the sleeve 42, until the outer end of the extrusion rod 421 contacts and squeezes the outer end of the gas pressure rod 432, and the gas pressure rod 432 is forced to push the gas pressure plate 431 to slide to the right along the inner wall of the gas pressure chamber 43, and the reverse thrust spring is deformed by the force, and the right side of the gas pressure plate 431 pushes the air into the filter chamber 433, and the nitrogen in the air is filtered out by the carbon molecular sieve, and then enters the air chamber 434. After the gas pressure rod 432 is out of contact with the pressure rod 42, the reverse thrust spring is generated. The reaction force resets the air pressure plate 431, and air is drawn from the outside through the pipeline. When the permanent magnet motor rotates, the above operation is repeated until the nitrogen pressure in the air cavity 434 reaches the pressure bearing limit of the pressure valve 1. The pressure valve 1 opens, and the nitrogen quickly enters the air ring 3 through the air guide pipe 435, and then sprays out from the air holes of the air ring 3. Nitrogen is an inert gas, which can reduce the oxygen concentration near the permanent magnet motor and retain the inert gas, so that it can play an explosion-proof role when the permanent magnet motor generates sparks during operation. In addition to the permanent magnet motor made of explosion-proof materials, it can further avoid explosions, and the explosion-proof effect is greatly improved.

[0033] The relationship between the jet frequency of air ring 3 and the operating power of the permanent magnet motor is:

[0034] HZ is the jet frequency of air ring 3, HZ max is the maximum jet frequency of gas ring 3, F is the operating power of the permanent magnet motor, F max is the maximum operating power of the permanent magnet motor;

[0035] The higher the operating power of the permanent magnet motor, the easier it is to generate sparks. At this time, the frequency of extracting gas from the air pressure chamber 43 and injecting it into the air cavity 434 is accelerated, thereby increasing the frequency of nitrogen spraying from the air ring 3, which is fully explosion-proof. On the contrary, the frequency of nitrogen spraying from the air ring 3 is reduced, which can not only prevent explosion but also avoid excessive wear of the structure, while relatively guaranteeing the service life of the carbon molecular sieve.

[0036] The left side of the air pressure chamber 43 is connected to an air intake pipe 436, and a one-way valve three is arranged inside the air intake pipe 436. The left side of the air pressure chamber 43 is connected to an exhaust pipe 437, and a one-way valve four is arranged inside the exhaust pipe 437. The inner diameter of the air intake pipe 436 is twice the inner diameter of the exhaust pipe 437.

[0037] An ups and downs cavity 44 is fixed to the bottom of the inner wall of the driving cavity 4, an ups and downs plate 441 is slidably connected to the inner wall of the ups and downs cavity 44, an ups and downs rod 442 is fixed above the ups and downs plate 441, and the upper end of the ups and downs rod 442 is spherical;

[0038] A sliding hole is provided in the middle of the sleeve 42, and a pressing rod 422 is slidably connected in the sliding hole. Both ends of the pressing rod 422 are spherical, and the inner end contacts one end of the extrusion rod 421. After the rising rod 442 rises, it contacts the outer end of the pressing rod 422. A limit block is provided on the outer side of the extrusion rod 421, and a fixed block is provided on the inner wall of the sleeve 42. A connecting spring 423 is fixedly installed between the limit block and the fixed block.

[0039] A conduit 45 is connected between the left side of the air pressure chamber 43 and the bottom of the fluctuation chamber 44, and a second pressure valve is arranged inside the conduit 45. The bottom of the fluctuation chamber 44 is connected to an external control valve pipeline;

[0040] Through the above steps, when the air pressure plate 431 slides left and right along the inner wall of the air pressure chamber 43, the external air is drawn to the left side of the air pressure plate 431 through the air inlet pipe 436, and then discharged to the outside through the exhaust pipe 437. Since the inner diameter of the exhaust pipe 437 is smaller than the inner diameter of the air inlet pipe 436, part of the gas cannot be discharged quickly and enters the conduit 45. When F=F max When the pressure plate 431 moves left and right, the reciprocating frequency reaches the maximum. At this time, the gas in the conduit 45 accumulates more and reaches the pressure limit of the pressure valve 2, so that the pressure valve 2 opens, and the gas enters the fluctuation chamber 44, thereby pushing the fluctuation plate 441 to move upward. The fluctuation plate 441 drives the fluctuation rod 442 to move upward, so that when the sleeve 42 rotates around the center of the gear 41, when it rotates to the bottom, the outer end of the pressing rod 422 and the upper end of the fluctuation rod 442 contact and squeeze each other, so that the pressing rod 422 is forced to move, and the pressing rod 422 passes The sliding hole slides and contacts and squeezes one end of the extrusion rod 421 through the spherical part at the other end, and the extrusion rod 421 moves to the right, and the connecting spring 423 is deformed by force. At this time, when the air pressure chamber 43 extracts gas and injects gas into the air cavity 434, the contact area between the extrusion rod 421 and the air pressure rod 432 increases, and the extrusion amplitude increases, thereby increasing the reciprocating stroke of the air pressure plate 431, and the frequency of nitrogen spraying from the air ring 3 is further improved, which can further reduce the oxygen near the permanent magnet motor, thereby achieving a full explosion-proof effect and further improving the safety performance.

[0041] The bottom of the base 2 is provided with a shock-absorbing cavity 5 fixed on both sides thereof, the inner wall of the shock-absorbing cavity 5 is slidably connected with a sliding plate 51, the bottom of the sliding plate 51 is fixed with a support rod 52, and the bottom end of the support rod 52 is fixed with a support seat 53;

[0042] A buffer spring 54 is fixed between the upper portion of the sliding plate 51 and the upper portion of the inner wall of the shock absorbing chamber 5;

[0043] When the permanent magnet motor is running, the permanent magnet motor itself vibrates. At this time, the support seat 53 is forced to slide along the inner wall of the shock-absorbing cavity 5 through the sliding plate 51, and the buffer spring 54 is deformed by the force to generate a reaction force, which can play a preliminary shock-absorbing role and reduce the demagnetization of the permanent magnet motor caused by vibration.

[0044] The surface of the sliding plate 51 is provided with two holes 511, the upper part of the ups and downs cavity 44 is connected with the upper part of the shock-absorbing cavity 5 by a pipeline, and the upper part of the ups and downs plate 441 is filled with hydraulic oil;

[0045] When the undulating plate 441 slides upward along the inner wall of the undulating cavity 44, the hydraulic oil above the undulating plate 441 is squeezed and enters the shock-absorbing cavity 5 through the pipeline. When the sliding plate 51 moves upward, the liquid is squeezed and flows back and forth through the hole 511, thereby further improving the buffering effect. At this time, the operating power of the permanent magnet motor reaches the maximum, and sufficient shock absorption is required, so high-intensity shock absorption is performed to fully protect the permanent magnet motor.

[0046] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0047] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mining explosion-proof direct-drive permanent magnet motor, comprising a permanent magnet motor, an output shaft (1) and a base (2), characterized in that: An air ring (3) is fixedly mounted on the outer ring of the permanent magnet motor, air holes are evenly arranged around the air ring (3), and a driving cavity (4) is fixed above the base (2); A notch is provided above the driving chamber (4); the driving chamber (4) comprises a gear (41), a sleeve (42), an extrusion rod (421), an air pressure chamber (43), an air pressure plate (431), an air pressure rod (432), a filter chamber (433), an air chamber (434) and an air guide tube (435); the permanent magnet motor is fixedly mounted above the base (2); the output shaft (1) is fixedly connected to the output end of the permanent magnet motor, and a toothed disc (11) is fixed on the outside; The toothed disc (11) is located in the slot and meshes with the gear (41); the bearing of the gear (41) is installed on the inner wall of the driving chamber (4); the sleeve (42) is fixedly installed on one side of the gear (41); the extrusion rod (421) is sleeved inside the sleeve (42); the air pressure chamber (43) is fixedly installed on the right side of the inner wall of the driving chamber (4); the air pressure plate (431) is slidably connected to the inner wall of the air pressure chamber (43); the air pressure rod (432) is fixedly installed on the left side of the air pressure plate (431); after the gear (41) rotates, the extrusion rod (421) and the air pressure rod (432) contact each other; both ends of the extrusion rod (421) and the outer end of the air pressure rod (432) are spherical; a reverse thrust spring is connected between the air pressure plate (431) and the right side of the inner wall of the air pressure chamber (43).

2. The explosion-proof direct-drive permanent magnet motor for mining according to claim 1, characterized in that: The right side of the air pressure chamber (43) is connected to an external pipeline, and a one-way valve 1 is provided in the pipeline; the right side of the air pressure chamber (43) is connected to a filter chamber (433) pipeline, and a one-way valve 2 is provided in the pipeline; a carbon molecular sieve is provided inside the filter chamber (433); the filter chamber (433) is connected to an air chamber (434) pipeline, and the air chamber (434) is connected to the inside of the air ring (3) through an air guide tube (435); A pressure valve 1 is arranged inside the air guide tube (435).

3. The explosion-proof direct-drive permanent magnet motor for mining according to claim 2, characterized in that: The relationship between the jet frequency of the air ring (3) and the operating power of the permanent magnet motor is: HZ is the jet frequency of the air ring (3), HZ max is the maximum jet frequency of the air ring (3), F is the operating power of the permanent magnet motor, F max is the maximum operating power of the permanent magnet motor.

4. The explosion-proof direct-drive permanent magnet motor for mining according to claim 3, characterized in that: The left side of the air pressure chamber (43) is connected to an air intake pipe (436), and a check valve three is arranged inside the air intake pipe (436). The left side of the air pressure chamber (43) is connected to an exhaust pipe (437), and a check valve four is arranged inside the exhaust pipe (437). The inner diameter of the air intake pipe (436) is twice the inner diameter of the exhaust pipe (437).

5. The explosion-proof direct-drive permanent magnet motor for mining according to claim 4, characterized in that: An undulating chamber (44) is fixed at the bottom of the inner wall of the driving chamber (4), an undulating plate (441) is slidably connected to the inner wall of the undulating chamber (44), an undulating rod (442) is fixed above the undulating plate (441), and the upper end of the undulating rod (442) is spherical; A sliding hole is provided in the middle of the sleeve (42), and a pressing rod (422) is slidably connected in the sliding hole. Both ends of the pressing rod (422) are spherical, and the inner end contacts one end of the extrusion rod (421). After the undulating rod (442) rises, it contacts the outer end of the pressing rod (422). A limit block is provided on the outer side of the extrusion rod (421), and a fixed block is provided on the inner wall of the sleeve (42). A connecting spring (423) is fixedly installed between the limit block and the fixed block. A conduit (45) is connected between the left side of the air pressure chamber (43) and the bottom of the fluctuation chamber (44), and a second pressure valve is arranged inside the conduit (45). The bottom of the fluctuation chamber (44) is connected to an external control valve pipeline.

6. The explosion-proof direct-drive permanent magnet motor for mining according to claim 5, characterized in that: A shock-absorbing cavity (5) is fixed on both left and right sides of the bottom of the base (2); a sliding plate (51) is slidably connected to the inner wall of the shock-absorbing cavity (5); a support rod (52) is fixed to the bottom of the sliding plate (51); and a support seat (53) is fixed to the bottom end of the support rod (52); A buffer spring (54) is fixed between the upper portion of the sliding plate (51) and the upper portion of the inner wall of the shock-absorbing cavity (5).

7. The explosion-proof direct-drive permanent magnet motor for mining according to claim 6, characterized in that: The surface of the sliding plate (51) is provided with two holes (511), the upper part of the undulating chamber (44) is connected to the upper part of the shock-absorbing chamber (5) by a pipeline, and the upper part of the undulating plate (441) is filled with hydraulic oil.

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