Cell culture perfusion device

Abstract

The invention relates to the technical field of cell culture, discloses a cell culture perfusion device and aims to solve the problem that cell culture operation is affected due to blockage of a filtering mechanism. Through the arrangement of the diaphragm pump and the hollow fiber membrane, when the diaphragm pump moves upwards, forward air pressure entering the diaphragm pump pushes a cell culture suspension to penetrate through the hollow fiber membrane and return to the reactor, at the moment, waste materials are retained in the hollow fiber membrane, and then when the diaphragm pump moves downwards, the waste materials are separated from the hollow fiber membrane. When the hollow fiber membrane is blocked, part of cell culture suspension in the reactor enters the hollow fiber membrane, at the moment, liquid flow on the outer side of the hollow fiber membrane synchronously flows inwards, then the hollow fiber membrane is backflushed, a gel layer deposited in the hollow fiber membrane is removed, and the probability that the hollow fiber membrane is blocked is reduced.

Description

Technical Field

[0001] The present application relates to the field of cell culture technology, and in particular to a cell culture perfusion device. Background Art

[0002] In the process of cell culture, in order to reduce the concentration of waste materials generated by cells accumulated in the reactor, perfusion devices are often used to participate in cell culture operations.

[0003] Some existing perfusion devices are mainly composed of a reactor and a filtering mechanism. When in use, a diaphragm pump in the filtering mechanism is used to intermittently pump part of the cell culture suspension in the reactor into the filtering mechanism and pass it through the filter element so that the waste materials in the cell culture suspension are filtered. Afterwards, as the diaphragm pump continues to operate, the filtered filtrate is returned to the reactor. Through the above actions, the concentration of waste materials accumulated in the reactor is reduced.

[0004] However, in the above process, since the waste materials are blocked on one side of the filter when the cell culture suspension passes through the filter, after a period of time, one side of the filter is easily blocked by the gel layer deposited by the waste materials, resulting in the ineffective use of the filter mechanism, thereby affecting the cell culture operation. Summary of the invention

[0005] The present application proposes a cell culture perfusion device, which has the advantage of reducing blockage and is used to solve the problem that the cell culture operation is affected due to blockage of the filter mechanism.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: a cell culture perfusion device, comprising: a reactor for culturing cells, a diaphragm pump is arranged on one side of the reactor, a filter chamber is fixedly installed on the upper side of the diaphragm pump, and an upper baffle and a lower baffle are fixedly installed in the filter chamber from top to bottom;

[0007] The lower side surface of the upper baffle plate and the upper side surface of the lower baffle plate are jointly fixedly mounted with a hollow fiber membrane, the cavity in the filter chamber located between the upper baffle plate and the lower baffle plate is a filter chamber, the cavity in the filter chamber located at the outer side of the hollow fiber membrane is an outer cavity, and the cavity in the filter chamber located at the inner side of the hollow fiber membrane is an inner cavity, the lower side of the inner cavity is connected with a diaphragm pump, an outer cavity through hole is longitudinally penetrated through the interior of the upper baffle plate and at a position corresponding to the outer cavity, an inner cavity through hole is longitudinally penetrated through the interior of the upper baffle plate and at a position corresponding to the inner cavity, a one-way valve is arranged on the lower side of the inner cavity through hole for preventing the liquid in the inner cavity from flowing out of the inner cavity through hole, a No. 1 pipe is fixedly connected to the upper side of the filter chamber, and the two sides of the No. 1 pipe are respectively connected to the cavity in the filter chamber located at the upper side of the upper baffle plate and the reactor, and a No. 2 pipe is fixedly mounted on one side of the filter chamber, and the two ends of the No. 2 pipe are respectively connected to the inner cavity and the collecting mechanism.

[0008] Furthermore, the hollow fiber membrane is divided into a fixed part, a folding part and a stretching part. The upper side of the fixed part is fixedly connected to the upper baffle, the No. 2 pipe passes through the fixed part and is connected to the inner cavity, the lower end of the fixed part is connected to the folding part, the lower end of the folding part is connected to the stretching part, the lower end of the stretching part is fixedly connected to the lower baffle, a folding mechanism is arranged at the center position of the inner side of the hollow fiber membrane, the folding mechanism is connected to the hollow fiber membrane, and is used to drive the folding and stretching of the folding part and the stretching part.

[0009] Furthermore, the folding mechanism includes an output rod, a force-applying member and a lifting member. The output rod is arranged at the central position of the inner side of the hollow fiber membrane, and the lower end of the output rod is fixedly installed with a force-applying member equidistantly around the circumference. The end of the force-applying member facing away from the output rod extends into the folded position of the lowermost side of the folding part, and the end of the force-applying member facing away from the output rod is fixedly connected to the inner side surface of the folding part. A lifting member is fixedly installed at the upper end of the filter chamber, and the upper end of the output rod passes through the upper baffle plate and the filter chamber, and forms a transmission connection with the lifting member. The parts of the output rod passing through the upper baffle plate and the filter chamber are sealed and slidably connected with the upper baffle plate and the filter chamber. When the output rod drives the force-applying member to move downward, the extended part will be gradually folded, and the folded part will be gradually unfolded.

[0010] Furthermore, the outer diameter of the folded portion is greater than the outer diameter of the extended portion, so that when the hollow fiber membrane is folded, the liquid in the outer cavity is squeezed.

[0011] Furthermore, a pressing plate is fixedly installed on the outer side of the fixing portion and above the folding portion.

[0012] Furthermore, a connecting plate is slidably installed in the inner cavity of the lifting member, a screw rod is rotatably installed in the inner cavity of the lifting member, the screw rod is threadedly connected to the connecting plate, and the upper end of the output rod is fixedly connected to the connecting plate.

[0013] Furthermore, the inner cavity of the lifting member forms a sealed sliding connection with the connecting plate, the screw rod forms a threaded sealed connection with the connecting plate, and shielding members are provided at positions between adjacent force-applying members, the outer side of the shielding member contacts the inner side of the folding portion, an air guide channel is opened at the center position inside the output rod, the lower end of the air guide channel is connected with the inner cavity, a sliding rod is installed with a sliding rod in a sealing and sliding manner inside the air guide channel, a slot is opened inside the output rod and passes through the position corresponding to the shielding member, a clamping rod is slidably clamped in the slot, one end of the clamping rod extends out of the slot and is fixedly connected to the upper position of the corresponding shielding member, the other end of the clamping rod extends into the air guide channel and is fixedly connected to the sliding rod, and the upper end of the air guide channel is connected to the cavity located at the lower side of the connecting plate in the lifting member.

[0014] This application has the following beneficial effects:

[0015] The present application provides a cell culture perfusion device, which is provided with a diaphragm pump and a hollow fiber membrane. When the diaphragm pump is in an upward stroke, the positive air pressure entering the diaphragm pump pushes the cell culture suspension to pass through the hollow fiber membrane and return to the reactor. At this time, the waste material is retained in the hollow fiber membrane. Thereafter, when the diaphragm pump is in a downward stroke, part of the cell culture suspension in the reactor enters the hollow fiber membrane. At this time, the liquid flow on the outside of the hollow fiber membrane flows inward synchronously, thereby recoils the hollow fiber membrane, thereby removing the gel layer deposited in the hollow fiber membrane and reducing the probability of blockage of the hollow fiber membrane.

[0016] Through the arrangement of the hollow fiber membrane, the output rod and the force-applying member, when the above-mentioned diaphragm pump completes a circulation stroke, the output rod drives the hollow fiber membrane to move through the force-applying member, causing the hollow fiber membrane to be partially folded. Through this action, the time that the fixed position of the hollow fiber membrane is in contact with the waste material is shortened, thereby reducing the probability of blockage of the hollow fiber membrane.

[0017] Through the arrangement of the hollow fiber membrane, the output rod and the force-applying member, when the hollow fiber membrane is partially folded, the distance between the outer side surface of the folded part of the hollow fiber membrane and the wall of the filter chamber is reduced, thereby squeezing the liquid in the outer cavity of the hollow fiber membrane, causing the liquid to recoil inward. At this time, the content of waste materials in the liquid in the outer cavity of the hollow fiber membrane is relatively low, so the liquid has a better cleaning effect on the hollow fiber membrane, thereby reducing the probability of blockage of the hollow fiber membrane.

[0018] Through the arrangement of the hollow fiber membrane and the baffle, when the hollow fiber membrane is partially folded, the baffle will be located on the inner side of the folded part of the hollow fiber membrane, thereby improving the barrier effect of the folded part of the hollow fiber membrane, so that during the diaphragm pump stroke, the liquid is not easy to pass through the folded part of the hollow fiber membrane, and the contact time between the fixed position of the hollow fiber membrane and the waste material is shortened, thereby reducing the probability of blockage of the hollow fiber membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute a part of the specification, illustrate embodiments disclosed in the present application and, together with the description, serve to explain the principles disclosed in the present application.

[0020] The present application can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0021] Figure 1 It is a schematic diagram of the reactor of the present invention;

[0022] Figure 2 This is a schematic diagram of the connection state between the diaphragm pump and the filter chamber in the first embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the internal structure of the diaphragm pump and the filter chamber in the first embodiment of the present invention;

[0024] Figure 4 For the present invention Figure 3 A partial enlarged schematic diagram of the structure at center A;

[0025] Figure 5 It is a schematic diagram of the internal structure of the diaphragm pump and the filter chamber in the second and third embodiments of the present invention;

[0026] Figure 6 For the present invention Figure 5 A partial enlarged schematic diagram of the structure at B in the middle;

[0027] Figure 7 For the present invention Figure 5 A partial enlarged schematic diagram of the structure at C in the middle;

[0028] Figure 8 This is a schematic diagram of the internal structure of the lifting member in the third embodiment of the present invention;

[0029] Fig. 9 Schematic diagram of the internal structure of the output rod in the third embodiment of the present invention.

[0030] In the figure: 1. Reactor; 2. Diaphragm pump; 3. Filter chamber; 4. Upper baffle; 5. Lower baffle; 6. Hollow fiber membrane; 60. Fixing part; 61. Folding part; 62. Extending part; 7. External cavity through hole; 8. Internal cavity through hole; 9. One-way valve; 10. No. 1 pipe; 11. No. 2 pipe; 12. Output rod; 13. Force-applying member; 14. Lifting member; 15. Pressing plate; 16. Shielding member; 17. Air guide channel; 18. Sliding rod; 19. Slot; 20. Clamping rod; 21. Connecting plate; 22. Screw. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] Example 1: Please refer to Figure 1-Figure 4 A cell culture perfusion device comprises a reactor 1 for culturing cells, a diaphragm pump 2 is arranged on one side of the reactor 1, a filter chamber 3 is fixedly installed on the upper side of the diaphragm pump 2, an upper baffle 4 and a lower baffle 5 are fixedly installed in the filter chamber 3 from top to bottom, a hollow fiber membrane 6 is fixedly installed on the lower side of the upper baffle 4 and the upper side of the lower baffle 5, a cavity between the upper baffle 4 and the lower baffle 5 in the filter chamber 3 is a filter cavity, a cavity located outside the hollow fiber membrane 6 in the filter cavity is an outer cavity, a cavity located inside the hollow fiber membrane 6 in the filter cavity is an inner cavity, the lower side of the inner cavity is connected to the diaphragm pump 2, an outer cavity through hole 7 is longitudinally penetrated in the upper baffle 4 and corresponding to the outer cavity An inner cavity through hole 8 is longitudinally opened inside the upper baffle plate 4 and at a position corresponding to the inner cavity, and a one-way valve 9 is arranged on the lower side of the inner cavity through hole 8 for preventing the liquid in the inner cavity from flowing out of the inner cavity through hole 8. A No. 1 pipe 10 is fixedly connected to the upper side of the filter chamber 3, one side of the No. 1 pipe 10 is connected to the cavity located at the upper side of the upper baffle plate 4 in the filter chamber 3, and the other side of the No. 1 pipe 10 is connected to the reactor 1. A No. 2 pipe 11 is fixedly installed on one side of the filter chamber 3, one end of the No. 2 pipe 11 is connected to the inner cavity, and the other side of the No. 2 pipe 11 is connected to a collecting mechanism (such as a collecting tank in the prior art, not shown in the figure), and valves are arranged on the No. 1 pipe 10 and the No. 2 pipe 11 for realizing the connection and disconnection of the No. 1 pipe 10 and the No. 2 pipe 11.

[0033] When the diaphragm pump 2 strokes upward, the positive air pressure entering the diaphragm pump 2 pushes the cell culture suspension in the inner cavity to pass through the hollow fiber membrane 6 (at this time, the one-way valve 9 is closed), and passes through the outer cavity, the outer cavity through hole 7 and the first tube 10, and then returns to the reactor 1. At this time, the waste material is retained on the inner side of the hollow fiber membrane 6. Afterwards, when the diaphragm pump 2 strokes downward, part of the cell culture suspension in the reactor 1 will be extracted through the first tube 10, so that part of the suspension pushes open the one-way valve 9 and enters the inner cavity through the inner cavity through hole 8, and the other part A part of it passes through the outer cavity through hole 7 and the hollow fiber membrane 6, and then enters the inner cavity. The liquid passing through the hollow fiber membrane 6 (due to the presence of some filtered filtrate in the outer cavity, the above filtrate first recoils the hollow fiber membrane 6) will have a recoil effect on the hollow fiber membrane 6, thereby removing the gel layer deposited on the inner side of the hollow fiber membrane 6 and reducing the probability of blockage of the hollow fiber membrane 6. After a period of time, the No. 1 pipe 10 is closed and the No. 2 pipe 11 is opened to make the diaphragm pump 2 stroke upward and squeeze some of the exhaust gas materials in the inner cavity into the collecting mechanism.

[0034] Example 2: Please refer to Figure 1-Figure 7 This embodiment is a further improvement of the first embodiment, and the improvement is that: the hollow fiber membrane 6 is divided into a fixed portion 60, a folded portion 61 and an extended portion 62, the upper side of the fixed portion 60 is fixedly connected to the upper baffle 4, the second tube 11 passes through the fixed portion 60 and is connected to the inner cavity, the lower end of the fixed portion 60 is connected to the folded portion 61, the lower end of the folded portion 61 is connected to the extended portion 62, the lower end of the extended portion 62 is fixedly connected to the lower baffle 5, an output rod 12 is provided at the center position of the inner side of the hollow fiber membrane 6, and a force member 13 is fixedly installed at the lower end of the output rod 12 at equidistant intervals in the circumferential direction, and the end of the force member 13 facing away from the output rod 12 extends into the lowermost side of the folded portion 61 In the folded position, one end of the force-applying member 13 facing away from the output rod 12 is fixedly connected to the inner side surface of the folding portion 61, and a lifting member 14 is fixedly installed on the upper end of the filter chamber 3. The upper end of the output rod 12 passes through the upper baffle plate 4 and the filter chamber 3, and forms a transmission connection with the lifting member 14 (the lifting member 14 and the output rod 12 are combined into a combination similar to an electric-controlled telescopic cylinder and a telescopic rod in the prior art). The part of the output rod 12 that passes through the upper baffle plate 4 and the filter chamber 3 forms a sealed sliding connection with the upper baffle plate 4 and the filter chamber 3. When the output rod 12 drives the force-applying member 13 to move downward, the extending portion 62 will gradually fold, and the folding portion 61 will gradually unfold. At this time, the states of the two are transformed into each other.

[0035] When the diaphragm pump 2 completes the circulation stroke, the lifting member 14 drives the output rod 12 to move downward (when the folding portion 61 is at the upper side of the extending portion 62), so that the force-applying member 13 moves synchronously and drives the folding portion 61 to extend downward, while the extending portion 62 gradually folds. Through this action, the time that the fixed position of the hollow fiber membrane 6 is in contact with the waste material is shortened, thereby reducing the probability of blockage of the hollow fiber membrane 6.

[0036] See also Figure 1-Figure 7 , the outer diameter of the folded portion 61 is greater than the outer diameter of the extended portion 62 .

[0037] When the extended portion 62 of the hollow fiber membrane 6 is gradually folded, the distance between the outer side surface of the folded part of the hollow fiber membrane 6 and the wall of the filter chamber 3 is reduced, thereby squeezing the liquid in the outer cavity, causing the liquid to recoil inward. At this time, the content of waste materials in the liquid in the outer cavity is relatively small, so that the liquid has a better cleaning effect on the hollow fiber membrane 6, thereby reducing the probability of blockage of the hollow fiber membrane 6.

[0038] See also Figure 1-Figure 7 A pressing plate 15 is fixedly installed on the outer side of the fixing portion 60 and above the folding portion 61 (a one-way valve 9 is provided at the inner cavity through hole 8 in the second embodiment, which is not shown in the figure).

[0039] The pressing plate 15 cooperates with the force applying member 13 to press the folding portion 61 up and down, thereby reducing the probability of liquid passing through the folding portion 61 and shortening the contact time between the fixed position of the hollow fiber membrane 6 and the waste material.

[0040] Example 3: Please refer to Figure 1-Figure 9 This embodiment is a further improvement of the second embodiment, and the improvement lies in that: shielding members 16 are provided between adjacent force-applying members 13, the outer side of the shielding members 16 contacts the inner side of the folding portion 61, an air guide channel 17 is provided at the central position inside the output rod 12, the lower end of the air guide channel 17 is communicated with the inner cavity, a sliding rod 18 is installed in a sealing manner inside the air guide channel 17, a card slot 19 is provided inside the output rod 12 and at a position corresponding to the shielding member 16, a card rod 20 is slidably connected in the card slot 19, one end of the card rod 20 extends out of the card slot 19 and is fixedly connected to the upper position of the corresponding shielding member 16, and the card rod 20 The other end of the lifting member 14 extends into the air guide channel 17 and is fixedly connected to the sliding rod 18. A connecting plate 21 is sealingly and slidably installed in the inner cavity of the lifting member 14. An air leakage hole is provided inside the lifting member 14 and located on the upper side of the connecting plate 21 to connect the external environment with the cavity in the lifting member 14 located on the upper side of the connecting plate 21. A screw rod 22 (including a motor that drives the screw rod 22 to rotate) is rotatably installed in the inner cavity of the lifting member 14. The screw rod 22 forms a threaded sealing connection with the connecting plate 21. The upper end of the output rod 12 is fixedly connected to the connecting plate 21. The upper end of the air guide channel 17 is connected to the cavity in the lifting member 14 located on the lower side of the connecting plate 21.

[0041] When the screw rod 22 drives the output rod 12 to move downward through the connecting plate 21, the connecting plate 21 will squeeze the gas in the cavity below the connecting plate 21 in the lifting member 14, so that the gas enters the air guide channel 17 and pushes the sliding rod 18, the clamping rod 20 and the shielding member 16 to move downward, thereby making the shielding member 16 always correspond to the folding position of the hollow fiber membrane 6. Through this action, the blocking effect of the folding position of the hollow fiber membrane 6 is improved, so that when the diaphragm pump 2 strokes, the liquid is not easy to pass through the folding position of the hollow fiber membrane 6, so that the contact time between the fixed position of the hollow fiber membrane 6 and the waste material is shortened, thereby reducing the probability of blockage of the hollow fiber membrane 6.

Claims

1. A cell culture perfusion device, comprising: A reactor (1) for culturing cells, wherein a diaphragm pump (2) is arranged on one side of the reactor (1), a filter chamber (3) is fixedly installed on the upper side of the diaphragm pump (2), and an upper baffle (4) and a lower baffle (5) are fixedly installed in sequence from top to bottom inside the filter chamber (3); The invention is characterized in that a hollow fiber membrane (6) is fixedly mounted on the lower side of the upper baffle (4) and the upper side of the lower baffle (5); the cavity located between the upper baffle (4) and the lower baffle (5) in the filter chamber (3) is a filter cavity; the cavity located outside the hollow fiber membrane (6) in the filter cavity is an outer cavity; the cavity located inside the hollow fiber membrane (6) in the filter cavity is an inner cavity; the lower side of the inner cavity is connected to the diaphragm pump (2); an outer cavity through hole (7) is longitudinally penetrated inside the upper baffle (4) and at a position corresponding to the outer cavity; the upper baffle ( An inner cavity through hole (8) is longitudinally opened inside the filter chamber (4) and at a position corresponding to the inner cavity, and a one-way valve (9) is arranged on the lower side of the inner cavity through hole (8) for preventing the liquid in the inner cavity from flowing out of the inner cavity through hole (8). A No. 1 pipe (10) is fixedly connected to the upper side of the filter chamber (3), and the two sides of the No. 1 pipe (10) are respectively connected to the cavity located on the upper side of the upper baffle (4) in the filter chamber (3) and the reactor (1), and a No. 2 pipe (11) is fixedly installed on one side of the filter chamber (3), and the two ends of the No. 2 pipe (11) are respectively connected to the inner cavity and the collection mechanism.

2. A cell culture perfusion device according to claim 1, characterized in that: The hollow fiber membrane (6) is divided into a fixed part (60), a folding part (61) and an extension part (62). The upper side of the fixed part (60) is fixedly connected to the upper baffle (4). The No. 2 pipe (11) passes through the fixed part (60) and is connected to the inner cavity. The lower end of the fixed part (60) is connected to the folding part (61). The lower end of the folding part (61) is connected to the extension part (62). The lower end of the extension part (62) is fixedly connected to the lower baffle (5). A folding mechanism is arranged at the center position of the inner side of the hollow fiber membrane (6). The folding mechanism is connected to the hollow fiber membrane (6) and is used to drive the folding part (61) and the extension part (62) to fold and extend.

3. A cell culture perfusion device according to claim 2, characterized in that: The folding mechanism comprises an output rod (12), a force-applying member (13) and a lifting member (14); the output rod (12) is arranged at the central position of the inner side of the hollow fiber membrane (6); the lower end of the output rod (12) is fixedly mounted with force-applying members (13) at equal intervals in the circumferential direction; one end of the force-applying member (13) facing away from the output rod (12) extends into the folded position at the lowermost side of the folding portion (61); and one end of the force-applying member (13) facing away from the output rod (12) is fixedly connected to the inner side surface of the folding portion (61). A lifting member (14) is fixedly mounted on the upper end of the filter chamber (3); the upper end of the output rod (12) passes through the upper baffle plate (4) and the filter chamber (3) and forms a transmission connection with the lifting member (14); the portion of the output rod (12) that passes through the upper baffle plate (4) and the filter chamber (3) forms a sealed sliding connection with the upper baffle plate (4) and the filter chamber (3); when the output rod (12) drives the force applying member (13) to move downward, the extension portion (62) is gradually folded and the folding portion (61) is gradually unfolded.

4. A cell culture perfusion device according to claim 3, characterized in that: The outer diameter of the folded portion (61) is greater than the outer diameter of the extended portion (62), so that when the hollow fiber membrane (6) is folded, the liquid in the outer cavity is squeezed.

5. A cell culture perfusion device according to claim 4, characterized in that: A pressing plate (15) is fixedly installed outside the fixing portion (60) and above the folding portion (61).

6. A cell culture perfusion device according to claim 5, characterized in that: A connecting plate (21) is slidably mounted in the inner cavity of the lifting member (14), a screw rod (22) is rotatably mounted in the inner cavity of the lifting member (14), the screw rod (22) and the connecting plate (21) are threadedly connected, and the upper end of the output rod (12) is fixedly connected to the connecting plate (21).

7. A cell culture perfusion device according to claim 6, characterized in that: The inner cavity of the lifting member (14) forms a sealed sliding connection with the connecting plate (21), the screw rod (22) forms a threaded sealed connection with the connecting plate (21), a shielding member (16) is provided between adjacent force-applying members (13), the outer side of the shielding member (16) contacts the inner side of the folding portion (61), an air guide channel (17) is provided at the central position inside the output rod (12), the lower end of the air guide channel (17) is communicated with the inner cavity, and a sliding rod (17) is installed in a sealed sliding manner inside the air guide channel (17). 8), a slot (19) is provided inside the output rod (12) and at a position corresponding to the shielding member (16), a slot (19) is slidably engaged with a slot rod (20), one end of the slot rod (20) extends out of the slot (19) and is fixedly connected to the upper position of the corresponding shielding member (16), the other end of the slot rod (20) extends into the air guide channel (17) and is fixedly connected to the slide bar (18), the upper end of the air guide channel (17) is communicated with a cavity located at the lower side of the connecting plate (21) in the lifting member (14).

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