Sealing assembly and metering device

Abstract

The utility model relates to a sealing assembly and a metering device, a cylinder body of the metering device is provided with a first connecting port, a seat body of the metering device is provided with a second connecting port, the first connecting port and the second connecting port are both stepped holes, and after the seat body is fixedly connected with the cylinder body, the first connecting port and the second connecting port are oppositely arranged to form a limiting cavity; the sealing assembly comprises a connecting base which is of an integrated tubular structure and is detachably and fixedly installed in the limiting cavity in a sealed mode, and a penetrating hole is formed in the middle of the connecting base; the normal-pressure sealing ring is detachably mounted in the connecting seat in a sealing manner and is in sliding sealing connection with a metering rod of the metering device; the pressure-bearing sealing ring is detachably mounted in the connecting seat in a sealing manner and is connected with the metering rod in a sliding and sealing manner; the guide structure is mounted in the connecting seat and is in sliding connection with the metering rod; the through hole is located between the normal-pressure sealing ring and the pressure-bearing sealing ring, the outer side of the outer wall of the metering rod is communicated with the inner wall of the limiting cavity, an isolation medium cavity is formed, and the sealing structure and the guide structure are convenient to replace.

Description

Technical Field

[0001] This utility model relates to the field of metering device technology, and in particular to a sealing component and a metering device. Background Technology

[0002] Plunger-type metering devices are widely used in automated glue application equipment. By controlling the movement distance of the metering rod within the cylinder, the amount of glue dispensed can be controlled, achieving quantitative glue application. Plunger-type metering devices typically employ a linear drive mechanism to move the metering rod within the cylinder, with the rod contacting a sealing and guiding structure mounted on the cylinder.

[0003] To ensure a proper seal in the glue chamber, a buffer medium chamber containing a softener is typically placed outside the glue seal. This buffer medium chamber is located on the base of the fixed linear drive structure, which is fixedly connected to the cylinder. This necessitates the installation of sealing structures on both the base and the cylinder. Since the metering rod is always in contact with the sealing and guiding structures, replacing the sealing and guiding structures requires disassembling the base and cylinder from the metering rod and then removing and replacing the sealing and guiding structures one by one.

[0004] The installation method of the above-mentioned sealing and guiding structure makes the operation of replacing the sealing and guiding structure complicated, inefficient, and labor-intensive. Utility Model Content

[0005] In response to the shortcomings of the existing production technology, the applicant provides a sealing component and a metering device, which facilitates the replacement of the sealing structure and the guiding structure, thereby improving efficiency and reducing labor intensity.

[0006] The technical solution adopted in this utility model is as follows:

[0007] A sealing assembly for a metering device, wherein the cylinder of the metering device is provided with a first connection port and the base of the metering device is provided with a second connection port, both the first and second connection ports being stepped holes, and after the base and the cylinder are fixedly connected, the first and second connection ports are arranged opposite to each other to form a limiting cavity.

[0008] The sealing assembly includes:

[0009] The connecting seat is an integral tubular structure that is sealed and detachably fixed in the limiting cavity. A through hole is provided in the middle of the connecting seat.

[0010] A normal pressure sealing ring is detachably and sealingly installed inside the connecting seat, and is slidably and sealingly connected to the measuring rod of the measuring device.

[0011] A pressure-bearing sealing ring is detachably and sealingly installed inside the connecting seat, and is slidably and sealingly connected to the metering rod.

[0012] A guide structure is installed in the connecting seat and slidably connected to the measuring rod;

[0013] The perforation is located between the atmospheric pressure sealing ring and the pressure bearing sealing ring, connecting the outer side of the metering rod to the inner wall of the limiting cavity, forming an isolation medium cavity.

[0014] As a further improvement to the above technical solution:

[0015] The number of perforations is multiple, and they are evenly distributed around the axis of the connector.

[0016] One end of the connector has a first slot for installing the pressure-bearing sealing ring, and the interior of the connector has a first groove for installing the normal pressure sealing ring.

[0017] The first groove is a closed structure, and the atmospheric pressure sealing ring is a soft sealing ring.

[0018] The pressure-bearing sealing ring includes an outer sealing ring and an inner sealing ring that are sealed and slidably fitted with the metering rod. The outer sealing ring is in direct contact with the material to be metered inside the cylinder. A second groove is provided at the bottom side wall of the first slot. The inner sealing ring is installed in the second groove. The outer sealing ring is sealed and connected to the side wall of the first slot outside the second groove.

[0019] It also includes a first support and a second support with the same structure and both being ring structures. The cross-section of the ring structure is L-shaped facing the center of the ring structure. The first support and the second support are stacked in the first slot and sealed to the first slot. The second groove is formed between the first support and the second support. The first support is sealed to the inner sealing ring, and the outer sealing ring is installed inside the second support.

[0020] A retaining ring is installed between the connecting seat and the first connecting port. The retaining ring confines the outer sealing ring within the first connecting port. The center of the retaining ring is provided with an expansion hole that fits with the metering rod, which is used to guide the material to be metered and output in the cylinder to the end face of the outer sealing ring.

[0021] The moving end of the linear drive mechanism of the metering device is floatingly connected to the metering rod through a floating connection structure, so that the metering rod is coaxial with the guide structure;

[0022] The other end of the connector is provided with a second slot, the first groove is located between the first slot and the second slot, and the guide structure is installed in the second slot. The guide structure is a bushing.

[0023] It also includes a first sealing ring, a second sealing ring, and a third sealing ring, which are sequentially installed on the outer wall of the connecting seat along the axial direction of the connecting seat. The first sealing ring is sealed to the first connecting port, and the second and third sealing rings are sealed to the second connecting port. The second and third sealing rings are located at the two ends of the axial direction of the isolation medium cavity, respectively.

[0024] A metering device comprising any of the sealing components described above.

[0025] The beneficial effects of this utility model are as follows:

[0026] This utility model has a compact and reasonable structure and is easy to operate. It uses a connecting seat as the skeleton for installing the guide structure and sealing structure. The connection between the seat and the cylinder can be used to limit the installation of the guide and the seal, making the overall assembly and disassembly of the guide structure and the sealing structure convenient, improving the maintenance efficiency of the metering device and reducing labor intensity.

[0027] This utility model also has the following advantages:

[0028] (1) The pressure-bearing sealing ring includes an inner sealing ring and an outer sealing ring. The sealing effect of the pressure-bearing sealing ring is improved by combining multiple seals.

[0029] (2) The pressure-bearing sealing ring is designed as a combined seal to improve the sealing effect. The first and second supports are stacked and installed in the first slot to form a groove for installing the sealing ring. The outer and inner sealing rings are radially and axially supported and fixed, which facilitates the disassembly and installation of the outer and inner sealing rings, and is especially friendly to hard sealing rings.

[0030] (3) A retaining ring is provided between the connecting seat and the first connecting port. An expansion hole is provided on the retaining ring. While the retaining ring axially limits the outer sealing ring, it also realizes the diversion of material in the cylinder and improves the sealing effect of the outer sealing ring.

[0031] (4) Under the condition of floating connection structure to connect the metering rod and the moving end, the bushing is selected as the guide structure. The guide dimension is longer and the guide effect is better. Metal bushing can be used to improve the service life of the guide structure. The guide structure and the sealing structure are installed in the same connecting seat to ensure the coaxiality of the guide structure and the sealing structure, so that the overall guiding and sealing effect between the guide structure and the metering rod is better. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the metering device of this utility model.

[0033] Figure 2 This is a cross-sectional view of the measuring device of this utility model.

[0034] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle.

[0035] Figure 4 This is a schematic diagram of the installation structure of the sealing assembly of this utility model.

[0036] Figure 5 This is a perspective view of the sealing component of this utility model.

[0037] Figure 6 This is an isometric sectional view of the sealing assembly of this utility model.

[0038] Figure 7 This is a schematic diagram of the assembly of a floating connection structure according to an embodiment of the present invention.

[0039] in:

[0040] 100. Feed valve; 200. Discharge valve;

[0041] 1. Linear drive mechanism; 11. Motor; 12. Lead screw; 13. Lead nut; 14. Moving end;

[0042] 2. Floating connection structure; 21. Limiting ring; 211. Annular groove; 212. Insertion hole; 22. First limiting part;

[0043] 3. Measuring rod; 31. Annular boss; 311. Second limiting part;

[0044] 4. Guiding structure;

[0045] 5. Connecting seat; 51. Through hole; 52. Retaining ring; 521. Expansion hole; 53. First groove; 54. Second slot; 55. First slot; 56. First support; 57. Second support;

[0046] 6. Sealing structure; 61. Atmospheric pressure sealing ring; 62. Inner sealing ring; 63. Outer sealing ring;

[0047] 71. First sealing ring; 72. Second sealing ring; 73. Third sealing ring;

[0048] 8. Cylinder body; 801. First connection port; 81. Feed inlet; 82. Discharge outlet;

[0049] 9. Base; 901. Second connection port; 902. Annular groove; 91. Supply port; 92. Transparent tube; 93. Support. Detailed Implementation

[0050] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0051] Example 1:

[0052] like Figures 1-4 As shown, the sealing assembly of this embodiment is used for a metering device. The cylinder 8 of the metering device is provided with a first connection port 801, and the seat 9 of the metering device is provided with a second connection port 901. Both the first connection port 801 and the second connection port 901 are stepped holes. After the seat 9 is fixedly connected to the cylinder 8, the first connection port 801 and the second connection port 901 are arranged opposite to each other to form a limiting cavity.

[0053] The sealing assembly includes a connecting seat 5, a normal pressure sealing ring 61, a pressure-bearing sealing ring, and a guide structure 4.

[0054] The connecting seat 5 is an integral tubular structure that is sealed and detachably fixed in the limiting cavity. A through hole 51 is provided in the middle of the connecting seat 5.

[0055] The atmospheric pressure sealing ring 61 is detachably and sealingly installed inside the connecting seat 5, and is slidably and sealingly connected to the metering rod 3 of the metering device.

[0056] The pressure-bearing sealing ring is detachably and sealed inside the connecting seat 5, and is slidably and sealed to the metering rod 3.

[0057] The guide structure 4 is installed in the connecting seat 5 and is slidably connected to the measuring rod 3;

[0058] Among them, the perforation 51 is located between the normal pressure sealing ring 61 and the pressure bearing sealing ring, connecting the outer side of the outer wall of the metering rod 3 with the inner wall of the limiting cavity to form an isolation medium cavity.

[0059] The metering device is a plunger-type metering device, and the isolation medium chamber is used to store the isolation medium. The sealing structure 6 includes an atmospheric pressure sealing ring 61 and a pressure-bearing sealing ring, and the guide structure 4 is installed in a position relative to the sealing structure 6 depending on the selected structure.

[0060] Specifically, a bracket 93 is provided on the base 9 of the metering device, and the bracket 93 fixes the mounting part of the linear drive mechanism 1 to the base 9. When the linear drive mechanism 1 is driven by a motor, the linear drive mechanism 1 includes a motor 11 and a lead screw 12 that is transmitted to the output end of the motor 11. A lead screw nut 13 is installed on the lead screw 12 and is fixedly installed in the moving end 14. The moving end 14 is slidably connected to the base 9 through a guide rod. The rotation of the lead screw 12 is converted into linear motion of the moving end 14 through the lead screw nut 13, thereby driving the metering rod 3 to move in a straight line.

[0061] The cylinder body 8 is used to store the material to be metered and output. The feed port 81 on the cylinder body 8 is equipped with a feed valve 100 to control the material entering the cylinder body 8, and the discharge port 82 is equipped with a discharge valve 200 to control the material being discharged from the cylinder body 8.

[0062] When it is necessary to replace the atmospheric pressure sealing ring 61, the pressure bearing sealing ring, and the guide structure 4, simply separate the cylinder body 8 from the seat body 9, and the operator can manually pull the connecting seat 5 out of the second connection port 901. It is not necessary to remove the metering rod 3, the bracket 93, and the linear drive mechanism 1. After pulling it out, replace the connecting seat 5 and the guide seal as a whole, or only replace the atmospheric pressure sealing ring 61, the pressure bearing sealing ring, and the guide structure 4. During installation, put the connecting seat 5, which is assembled with the atmospheric pressure sealing ring 61, the pressure bearing sealing ring, and the guide structure 4, on the end of the metering rod 3, insert it into the second connection port 901, and then reconnect the cylinder body 8 and the seat body 9.

[0063] Using the connecting seat 5 as the skeleton for installing the guide structure 4 and the sealing structure 6, the guide and seal can be quickly positioned and installed by connecting the seat body 9 and the cylinder body 8. This makes the overall assembly and disassembly of the guide structure 4 and the sealing structure 6 convenient, improves the maintenance efficiency of the metering device, and reduces labor intensity.

[0064] like Figures 3-6 As shown, the sealing assembly of this embodiment also includes a first sealing ring 71, a second sealing ring 72 and a third sealing ring 73 sequentially installed on the outer wall of the connecting seat 5 along the axial direction of the connecting seat 5. The first sealing ring 71 is sealed to the first connecting port 801, and the second sealing ring 72 and the third sealing ring 73 are sealed to the second connecting port 901. The second sealing ring 72 and the third sealing ring 73 are respectively located at the two ends of the axial direction of the isolation medium cavity.

[0065] Specifically, the first sealing ring 71, the second sealing ring 72, and the third sealing ring 73 are all O-rings; the seat body 9 is provided with a supply port 91 that connects to the isolation medium cavity, and the side wall of the limiting cavity is provided with an annular groove 902. The supply port 91 is located on the bottom surface of the annular groove 902, and the second sealing ring 72 and the third sealing ring 73 are respectively located on the outer sides of the axial ends of the annular groove 902; a transparent tube 92 is installed at the supply port 91, and the transparent tube 92 is located outside the seat body 9 for storing the isolation medium.

[0066] When the material to be metered and output is glue, the isolation medium is a plasticizer, which is located between the air and the glue to prevent the glue from seeping into the pressure-bearing sealing ring and metering rod 3 and solidifying upon contact with the air, thus affecting the sealing effect. It also has a lubricating effect, and the color of the plasticizer inside the transparent tube 92 can be used to observe the glue leakage.

[0067] Furthermore, there are multiple perforations 51, evenly distributed around the axis of the connecting seat 5.

[0068] Example 2:

[0069] Based on Example 1, such as Figure 6As shown, in the sealing assembly of this embodiment, one end of the connecting seat 5 is provided with a first slot 55 for installing a pressure-bearing sealing ring, and the inside of the connecting seat 5 is provided with a first groove 53 for installing a normal pressure sealing ring 61.

[0070] In another specific embodiment, the first groove 53 is a closed structure, and the atmospheric pressure sealing ring 61 is a soft sealing ring. The closed structure means that the first groove 53 is formed on the connecting seat 5 by machining, and the atmospheric pressure sealing ring 61 needs to be compressed and deformed to extend into the middle of the connecting seat 5 before filling the first groove 53.

[0071] During the operation of the plunger-type metering device, there is a certain pressure inside the cylinder 8. A pressure-bearing sealing ring is used to isolate the medium and the material. In order to ensure the sealing effect, the pressure-bearing sealing ring is a combination seal.

[0072] Furthermore, in the sealing assembly of this embodiment, the pressure-bearing sealing ring includes an outer sealing ring 63 and an inner sealing ring 62 that are sealed and slidably fitted with the metering rod 3. The outer sealing ring 63 is in direct contact with the material to be metered inside the cylinder 8. A second groove is provided at the bottom side wall of the first slot 55. The inner sealing ring 62 is installed in the second groove, and the outer sealing ring 63 is sealed to the side wall of the first slot 55 outside the second groove.

[0073] The pressure-bearing sealing ring includes an inner sealing ring 63 and an outer sealing ring 62. The sealing effect of the pressure-bearing sealing ring is improved by combining multiple seals.

[0074] To facilitate the installation of rigid sealing rings, such as Figure 3 , Figure 6 As shown, the sealing assembly in this embodiment also includes a first support 56 and a second support 57 with the same structure and both being annular. The cross-section of the annular structure is L-shaped facing the center of the annular structure. The first support 56 and the second support 57 are stacked in the first slot 55 and sealed to the first slot 55. A second groove is formed between the first support 56 and the second support 57. The first support 56 is sealed to the inner sealing ring 62. The outer sealing ring 63 is installed inside the second support 57.

[0075] Specifically, O-rings are installed on the outer ring sidewalls of the first support 56 and the second support 57.

[0076] The first support 56 and the second support 57, which are stacked and installed in the first slot 55, form a groove for installing the sealing ring. This provides radial and axial support and fixation for the outer sealing ring 63 and the inner sealing ring 62, making it easier to disassemble and install the outer sealing ring 63 and the inner sealing ring 62, especially for hard sealing rings.

[0077] Furthermore, a retaining ring 52 is installed between the connecting seat 5 and the first connecting port 801. The retaining ring 52 confines the outer sealing ring 63 within the first connecting port 801. The center of the retaining ring 52 is provided with an expansion hole 521 that is clearance-fitted with the metering rod 3, which is used to guide the material to be metered and output in the cylinder 8 to the end face of the outer sealing ring 63.

[0078] When the end face of the outer sealing ring 63 is a V-groove, the contour surface of the expansion hole 521 will guide the material into the V-groove.

[0079] A retaining ring 52 is provided between the connecting seat 5 and the first connecting port 801. An expansion hole 521 is provided on the retaining ring 52. While the retaining ring 52 axially limits the outer sealing ring 63, it also realizes the diversion of material in the cylinder 8 and improves the sealing effect of the outer sealing ring 63.

[0080] Example 3:

[0081] Based on the above embodiments, in the sealing assembly of this embodiment, the moving end 14 of the linear drive mechanism 1 of the metering device is floatingly connected to the metering rod 3 through the floating connection structure 2, so that the metering rod 3 is coaxial with the guide structure 4;

[0082] The other end of the connector 5 is provided with a second slot 54. The first groove 53 is located between the first slot 55 and the second slot 54. The guide structure 4 is installed in the second slot 54. The guide structure 4 is a bushing.

[0083] Specifically, the guide structure 4 is an oil-free metal bushing made of brass, and the ratio of the length of the guide structure 4 to the diameter of the measuring rod 3 is 0.4-2. The guide structure 4 is located between the sealing structure 6 and the moving end 14.

[0084] The floating connection structure 2 can use a conventional floating joint or a non-standard structure.

[0085] The guide structure 4 in the prior art usually adopts multiple guide wear-resistant lip strips, which correspond to the normal pressure sealing ring 61 and the pressure sealing ring respectively. The hardness is relatively soft and not wear-resistant enough.

[0086] In the sealing assembly of this embodiment, under the condition that the metering rod 3 and the moving end 14 are floatingly connected by the floating connection structure 2, a bushing is selected as the guide structure 4. The guide dimension is longer and the guide effect is better. A metal bushing can be used to improve the service life of the guide structure 4. The guide structure 4 and the sealing structure 6 are installed in the same connecting seat 5 to ensure the coaxiality of the guide structure 4 and the sealing structure 6, so that the overall guiding and sealing effect between them and the metering rod 3 is better.

[0087] In another embodiment, the floating connection structure 2 is a non-standard design, as shown in the figure. Figure 2 , Figure 7As shown, the measuring rod 3 has its end located inside the cylinder 8, and its middle outer circumference is in a sealed sliding fit with the cylinder 8. An annular boss 31 is provided on the outer circumference of its head end. The floating connection structure 2 includes a limiting ring 21 fixedly installed on the moving end 14. The limiting ring 21 has an annular groove 211 that cooperates with the annular boss 31, limiting the annular boss 31 between the annular groove 211 and the moving end 14. There is a first gap between the annular boss 31 and the annular groove 211 along the axial direction of the measuring rod 3, and a second gap between the annular boss 31 and the annular groove 211 along the radial direction of the measuring rod 3. The first gap and the second gap enable the measuring rod 3 to be floatingly connected to the moving end 14.

[0088] Specifically, the first gap refers to the maximum displacement that the annular boss 31 can move axially along the metering rod 3 within the annular groove 211, and the second gap refers to the maximum displacement that the annular boss 31 can move radially along the metering rod 3 within the annular groove 211. The radial direction of the metering rod 3 includes multiple diameter directions. The dimensions of the second gap and the first gap are compatible, which can accommodate the processing and assembly errors of the components associated with the metering rod 3. It is mainly used to absorb the coaxiality error between the metering rod 3 and the guide structure 4 and the sealing structure 6.

[0089] The measuring rod 3 is floatingly connected to the moving end 14 by the floating connection structure 2, so that the measuring rod 3 can move axially and radially under the action of external force. The measuring rod 3 can also deflect in the center hole of the annular groove 211, so that the axis of the measuring rod 3 is at an angle relative to the moving direction of the moving end 14.

[0090] like Figure 7 As shown, the annular groove 211 is circular, the annular boss 31 is circular, and the second gap is located between the outer circumferential surface of the annular boss 31 and the sidewall of the annular groove 211. The gap should be sufficient to absorb assembly and machining errors.

[0091] To prevent the annular groove 211 and the annular boss 31 from rotating relative to each other during the use of the plunger-type metering device, which would cause the metering rod 3 to rotate relative to the sealing structure 6 and affect the sealing performance, a first limiting part 22 is provided on the side wall of the annular groove 211, and a second limiting part 311 corresponding to the first limiting part 22 is provided on the outer peripheral surface of the annular boss 31. The second limiting part 311 cooperates with the first limiting part 22 to restrict the rotation of the metering rod 3 relative to the limiting ring 21, and a second gap is provided between the first limiting part 22 and the second limiting part 311.

[0092] The second limiting part 311 is a plane, and the bottom of the annular groove 211 is provided with an insertion hole 212. The first limiting part 22 is a pin structure, and the first limiting part 22 is inserted into the insertion hole 212.

[0093] Specifically, the number of first limiting parts 22 can be one or more. When there are two first limiting parts 22, they can be set along a diameter direction of the measuring rod 3, and the number and position of the corresponding second limiting parts 311 match the first limiting parts 22.

[0094] The floating connection structure 2, which uses the annular boss 31 and the annular groove 211 to cooperate, allows the position of the measuring rod 3 to move adaptively according to the structure that needs to be coaxially coupled. The axial length of the floating connection structure 2 is small, and without increasing the overall size of the plunger-type measuring device, the measuring rod 3 is made coaxial with the guide structure 4, sealing structure 6 and other structures, thereby extending the service life of the guide structure 4 and the sealing structure 6.

[0095] When the cylinder 8 needs to discharge material, the discharge valve 200 is opened, and the metering rod 3 moves into the cylinder 8. Under the action of the material pressure in the cylinder 8, the annular boss 31 of the metering rod 3 contacts the moving end 14.

[0096] When material needs to be fed into the cylinder 8, the metering rod 3 moves out of the cylinder 8 and simultaneously opens the feed valve 100. The feed pipeline delivers material into the cylinder 8. When the cylinder 8 is full of material, under the pressure of the material in the cylinder 8, the annular boss 31 of the metering rod 3 contacts the moving end 14.

[0097] Example 4:

[0098] This embodiment provides a metering device, including the sealing assembly described in any of the above embodiments.

[0099] The above description is an explanation of the present utility model and not a limitation thereof. The scope of the present utility model is defined by the claims. Within the protection scope of the present utility model, any form of modification may be made.

Claims

1. A sealing assembly, characterized in that: For a metering device, the cylinder (8) of the metering device is provided with a first connection port (801), and the base (9) of the metering device is provided with a second connection port (901). The first connection port (801) and the second connection port (901) are both stepped holes. After the base (9) and the cylinder (8) are fixedly connected, the first connection port (801) and the second connection port (901) are arranged opposite to each other to form a limiting cavity. The sealing assembly includes: The connecting seat (5) is an integral tubular structure that is sealed and detachably fixed in the limiting cavity. A through hole (51) is provided in the middle of the connecting seat (5). The atmospheric pressure sealing ring (61) is detachably and sealingly installed inside the connecting seat (5) and is slidably and sealingly connected to the measuring rod (3) of the measuring device; The pressure-bearing sealing ring is detachably and sealed inside the connecting seat (5) and is slidably and sealed to the metering rod (3); The guide structure (4) is installed in the connecting seat (5) and is slidably connected to the measuring rod (3); The perforation (51) is located between the atmospheric pressure sealing ring (61) and the pressure-bearing sealing ring, connecting the outer side of the outer wall of the metering rod (3) with the inner wall of the limiting cavity to form an isolation medium cavity.

2. The seal assembly of claim 1, wherein: The number of perforations (51) is multiple, and they are evenly distributed around the axis of the connecting seat (5).

3. The seal assembly of claim 1, wherein: The connecting seat (5) has a first slot (55) for installing the pressure-bearing sealing ring at one end, and a first groove (53) for installing the normal pressure sealing ring (61) inside the connecting seat (5).

4. The seal assembly of claim 3, wherein: The first groove (53) is a closed structure, and the atmospheric pressure sealing ring (61) is a soft sealing ring.

5. The seal assembly of claim 3, wherein: The pressure-bearing sealing ring includes an outer sealing ring (63) and an inner sealing ring (62) that are sealed and slidably fitted with the metering rod (3). The outer sealing ring (63) is in direct contact with the material to be metered in the cylinder (8). A second groove is provided at the bottom side wall of the first slot (55). The inner sealing ring (62) is installed in the second groove. The outer sealing ring (63) is sealed and connected to the side wall of the first slot (55) outside the second groove.

6. The seal assembly of claim 5, wherein: It also includes a first support (56) and a second support (57) with the same structure and both being ring structures. The cross-section of the ring structure is L-shaped facing the center of the ring structure. The first support (56) and the second support (57) are stacked in the first slot (55) and sealed to the first slot (55). The second groove is formed between the first support (56) and the second support (57). The first support (56) is sealed to the inner sealing ring (62). The outer sealing ring (63) is installed inside the second support (57).

7. The seal assembly of claim 5, wherein: A retaining ring (52) is installed between the connecting seat (5) and the first connecting port (801). The retaining ring (52) confines the outer sealing ring (63) within the first connecting port (801). The center of the retaining ring (52) is provided with an expansion hole (521) that is clearance-fitted with the metering rod (3) to guide the material to be metered and output in the cylinder (8) to the end face of the outer sealing ring (63).

8. The seal assembly of claim 3, wherein: The moving end (14) of the linear drive mechanism (1) of the metering device is floatingly connected to the metering rod (3) through the floating connection structure (2), so that the metering rod (3) is coaxial with the guide structure (4); The other end of the connecting seat (5) is provided with a second slot (54), the first groove (53) is located between the first slot (55) and the second slot (54), and the guide structure (4) is installed in the second slot (54). The guide structure (4) is a bushing.

9. The seal assembly of claim 1, wherein: It also includes a first sealing ring (71), a second sealing ring (72) and a third sealing ring (73) sequentially installed on the outer wall of the connecting seat (5) along the axial direction of the connecting seat (5). The first sealing ring (71) is sealed to the first connecting port (801), and the second sealing ring (72) and the third sealing ring (73) are sealed to the second connecting port (901). The second sealing ring (72) and the third sealing ring (73) are respectively located at the two ends of the axial direction of the isolation medium cavity.

10. A metering device characterized by: Includes the sealing assembly as described in any one of claims 1-9.

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