A mechanical sealing device for petrochemical pump

Abstract

The present invention discloses a mechanical sealing device for a petrochemical pump, which relates to the technical field of petrochemical pump sealing, and comprises a mounting barrel, wherein the mounting barrel is threadedly connected to a barrel cover, wherein a first sealing ring is placed on the barrel cover through an annular groove, wherein the barrel cover is slidably connected to a push rack, wherein the inner ring and the outer ring of the push rack are both placed with a second sealing ring through an annular groove, wherein a third sealing ring is placed between the end face of the push rack away from the barrel cover and the housing of the petrochemical pump, wherein a one-way pneumatic syringe is installed on the mounting barrel, wherein a rotating rack is bolted to the side of the pump shaft close to the barrel cover, wherein the rotating rack is in contact with the barrel cover. The present invention uses a one-way pneumatic syringe to stably inject pressure into the mounting barrel, so that the push rack can automatically and progressively seal when the sealing end face of the third sealing ring is worn, so that the third sealing ring is always in close contact between the petrochemical pump and the pump shaft, thereby avoiding sealing failure due to wear of the sealing end face.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical pump sealing, and in particular to a mechanical sealing device for a petrochemical pump. Background Art

[0002] The mechanical seal in the petrochemical pump uses a sealing ring to close the gap between the pump shaft and the pump casing to ensure that the pumped medium will not leak into the external environment through the shaft gap during the pumping process.

[0003] Traditional static seals rely on the elasticity of the sealing material itself, lack an active compensation mechanism, and are unable to cope with wear or shape changes on the sealing end face. Once the sealing material ages or deforms, the sealing effect will be greatly reduced. Although progressive sealing can be achieved by means of compression springs, the elastic force of compression springs is greatly affected by factors such as temperature, humidity, and corrosion. They are prone to fatigue failure after long-term use. As the usage time and working environment change, the elastic force of the spring will gradually weaken, resulting in unstable thrust, which in turn leads to weakened sealing performance and a greater risk of sealing failure. Sealing failure will lead to leakage of the conveying medium, which will not only waste resources but also may pollute the environment. Summary of the invention

[0004] In order to overcome the technical problems raised in the above background technology, the present invention provides a mechanical sealing device for a petrochemical pump.

[0005] The cam is provided with a first sealing ring, the second sealing ring is provided with a second sealing ring through an annular groove, the cam cover is slidably connected to a push frame, the inner ring and the outer ring of the push frame are provided with a second sealing ring through an annular groove, a third sealing ring is provided between the end surface of the push frame away from the side of the cylinder cover and the housing of the petrochemical pump, the cam is provided with a one-way pneumatic syringe, the side of the pump shaft close to the cylinder cover is bolted to a rotating frame, the rotating frame contacts the cylinder cover, the rotating frame is slidably connected to a locking frame, the one-way pneumatic syringe contacts the locking frame, the end surface of the locking frame close to the one-way pneumatic syringe is set to a concave surface, a first spring is fixedly connected between the rotating frame and the locking frame, and the pump shaft passes through the rotating frame, the cylinder cover, the first sealing ring, the mounting barrel, the push frame, the second sealing ring of the inner ring and the third sealing ring.

[0006] It is particularly preferred that the side of the third sealing ring away from the rotating frame is configured in a truncated cone shape for wedging into a gap between the pump shaft and the petrochemical pump housing.

[0007] It is particularly preferred that the one-way pneumatic syringe consists of a syringe barrel, a piston rod, an elastic member, a one-way air inlet pipe and a one-way air outlet pipe, the syringe barrel is fixedly connected to the outer wall of the mounting barrel, the piston rod is slidably connected to the syringe barrel, one end of the piston rod close to the locking frame intermittently contacts the locking frame, the end surface of the piston rod close to the locking frame is set as a convex surface, the elastic member is fixedly connected between the piston rod and the inner wall of the syringe barrel, the one-way air inlet pipe is fixedly connected to the top of the syringe barrel, and the one-way air outlet pipe is connected between the mounting barrel and the syringe barrel.

[0008] It is particularly preferred that a discharge pipe is further included, and the discharge pipe is connected to the bottom of the installation tube near the side of the third sealing ring.

[0009] It is particularly preferred that a card frame is further included, which is slidably connected to a side of the rotating frame close to the locking frame, a second spring is fixedly connected between the card frame and the rotating frame, a friction block is fixedly connected to the rotating frame, a friction frame is slidably connected to one side of the card frame, the friction frame is in contact with the friction block, a third spring is fixedly connected between the card frame and the friction frame, a blocking frame for automatically locking the locking frame is slidably connected to the other side of the card frame, and a first tension spring is fixedly connected between the card frame and the blocking frame.

[0010] Particularly preferably, a side of the card holder close to the locking frame is arranged as an inclined surface, and the card holder is pressed and matched with the locking frame via the inclined surface.

[0011] Particularly preferably, a side of the retaining frame close to the locking frame is provided with a wedge-shaped surface, and the retaining frame is extruded and matched with the locking frame through the wedge-shaped surface.

[0012] It is particularly preferred that a sealing frame is further included, which is slidably connected to a side of the mounting tube away from the tube cover, and a side of the push frame close to the sealing frame is provided with exhaust holes evenly distributed along a ring shape, and the sealing frame blocks the exhaust holes, and a side of the push frame close to the exhaust holes is provided with clamping holes evenly distributed along the circumferential direction, and a side of the push frame close to the clamping holes is provided with an extrusion surface, a fourth spring is fixedly connected between the sealing frame and the mounting tube, and the sealing frame is fixed with elastic telescopic blocks evenly distributed in the circumferential direction, the elastic telescopic blocks are extruded and matched with the extrusion surface, and the elastic telescopic blocks correspond one-to-one to the exhaust holes.

[0013] Particularly preferably, it further comprises a second tension spring distributed in an annular shape, wherein the second tension spring is fixed between the push frame and the cylinder cover.

[0014] It is particularly preferred that a guide ring is further included, which is fixed to a side of the installation tube close to the third sealing ring, the guide ring is in contact with the third sealing ring, and the guide ring guides the leaked medium to the discharge pipe through the guide surface.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) The present invention uses a one-way pneumatic syringe to steadily inject pressure into the installation barrel, so that the push frame can automatically and progressively seal when the sealing end surface of the third sealing ring is worn, so that the third sealing ring is always in close contact between the petrochemical pump and the pump shaft, avoiding sealing failure caused by wear of the sealing end surface;

[0017] (2) Compared with the method of directly putting a compression spring on the push frame for progressive sealing, the air pressure value of the push frame to move rightward at any time is relatively stable, so that the thrust for pushing the third sealing ring to move rightward is relatively stable, and then the sealing between the right side of the third sealing ring and the petrochemical pump housing is relatively stable;

[0018] (3) The present invention prolongs the time for the lock frame to reset, reduces the contact frequency between the lock frame and the piston rod, reduces wear and fatigue, and prolongs the service life of the lock frame or one-way pneumatic syringe and other components through the friction fit between the friction block and the friction frame;

[0019] (4) When the device of the present invention is disassembled for maintenance or cleaning, the pumping medium contacted by the surface of the second sealing ring is blown away by the gas in the left part of the installation tube, thereby reducing the risk of erosion of the second sealing ring;

[0020] (5) When the seal frame is unlocked, the present invention uses the reset second tension spring to pull the push frame to the left, so that the space in the left part of the installation tube is compressed and reduced, thereby accelerating the discharge of gas in the left part of the installation tube through the exhaust hole, increasing the wind force blowing toward the second sealing ring, and improving the decontamination effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional structural schematic diagram of the mechanical sealing device for petrochemical pump machine of the present invention;

[0022] Figure 2 It is a three-dimensional structural schematic diagram of the petrochemical pump, pump shaft, mounting barrel and other components of the present invention;

[0023] Figure 3 It is a three-dimensional structural schematic diagram of the cylinder cover, the first sealing ring and the push frame and other components of the present invention;

[0024] Figure 4 It is a three-dimensional structural separation diagram of the push frame, the second sealing ring, the third sealing ring and other components of the present invention;

[0025] Figure 5 It is a three-dimensional structural schematic diagram of the first spring, the clamping frame, the second spring and other components of the present invention;

[0026] Figure 6It is a three-dimensional structural schematic diagram of the friction block, friction frame, third spring and other components of the present invention;

[0027] Figure 7 It is a three-dimensional structural schematic diagram of the push frame, the fourth spring and the elastic telescopic block and other components of the present invention;

[0028] Figure 8 It is a three-dimensional structural schematic diagram of the push frame, the sealing frame and the elastic telescopic block of the present invention;

[0029] Fig. 9 It is a three-dimensional structural schematic diagram of the installation cylinder, guide ring and other components of the present invention;

[0030] Fig.10 It is a schematic diagram of the three-dimensional structure of the third sealing ring and the guide ring of the present invention.

[0031] In the figure: 1. petrochemical pump; 2. pump shaft; 3. mounting cylinder; 301. discharge pipe; 4. cylinder cover; 5. first sealing ring; 6. push frame; 601. second sealing ring; 7. third sealing ring; 8. one-way pneumatic syringe; 9. rotating frame; 10. locking frame; 11. first spring; 12. clamping frame; 13. second spring; 14. friction block; 15. friction frame; 16. third spring; 17. retaining frame; 18. first tension spring; 19. sealing frame; 20. exhaust hole; 21. clamping hole; 22. extrusion surface; 23. fourth spring; 24. elastic telescopic block; 25. second tension spring; 26. guide ring; 27. guide surface. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0033] Embodiment 1: A mechanical seal device for a petrochemical pump, such as Figure 1-Figure 4As shown, it includes a mounting cylinder 3, the bottom right side of the mounting cylinder 3 is connected with a discharge pipe 301, the left side of the mounting cylinder 3 is threadedly connected with a cylinder cover 4, the cylinder cover 4 is provided with a first sealing ring 5 through an annular groove, the first sealing ring 5 is used to seal the gap between the mounting cylinder 3 and the cylinder cover 4, the cylinder cover 4 is slidably connected with a push frame 6 along the left and right directions, the push frame 6 is located in the mounting cylinder 3, the right inner ring and outer ring of the push frame 6 are both provided with a second sealing ring 601 through an annular groove, the second sealing ring 601 of the inner ring is used to seal the pump shaft 2 and The second sealing ring 601 of the outer ring is used to seal the gap between the installation tube 3 and the push frame 6. A third sealing ring 7 is placed between the right end face of the push frame 6 and the shell of the petrochemical pump 1. The pumping medium adhered to the third sealing ring 7 falls to the discharge pipe 301 under the action of gravity and is discharged out of the device through the discharge pipe 301 to prevent the leaked pumping medium from remaining in the device. The right side of the third sealing ring 7 is set to a truncated cone shape to wedge into the gap between the pump shaft 2 and the shell of the petrochemical pump 1. A one-way pneumatic syringe 8 is installed on the top of the mounting cylinder 3. The one-way pneumatic syringe 8 consists of a syringe, a piston rod, an elastic member, a one-way air inlet pipe and a one-way air outlet pipe. The syringe is fixed to the top outer wall of the mounting cylinder 3. The piston rod is slidably connected to the syringe. The left end face of the piston rod is set as a convex surface. The elastic member is fixed between the piston rod and the inner wall of the syringe. The one-way air inlet pipe is fixedly connected to the top of the syringe. The one-way air outlet pipe is connected between the mounting cylinder 3 and the syringe. The pump shaft 2 is bolted to the side close to the cylinder cover 4. There is a rotating frame 9, the right side of the rotating frame 9 contacts the left side of the cylinder cover 4, the rotating frame 9 is slidably connected to the locking frame 10 along the left and right directions, the left end of the piston rod of the one-way pneumatic syringe 8 intermittently contacts the locking frame 10, and the end surface of the locking frame 10 close to the one-way pneumatic syringe 8 is set as a concave surface. A first spring 11 is fixedly connected between the rotating frame 9 and the locking frame 10, and the pump shaft 2 passes through the rotating frame 9, the cylinder cover 4, the first sealing ring 5, the mounting cylinder 3, the pushing frame 6, the second sealing ring 601 of the inner ring and the third sealing ring 7 from left to right.

[0034] In order to enable the third sealing ring 7 to automatically move to the right to the right end face and to be in close contact with the housing of the petrochemical pump 1 again when the right end face of the third sealing ring 7 is worn, it is specifically achieved through the following operations: when the petrochemical pump 1 is running, the pump shaft 2 drives the rotating frame 9 to rotate, thereby driving the locking frame 10 and the first spring 11 to rotate, and the locking frame 10 squeezes the piston rod of the one-way pneumatic syringe 8, so that the gas in the one-way pneumatic syringe 8 enters the left part of the mounting tube 3 in one direction. When the left part of the mounting tube 3 and the pump shaft 2 are filled with gas, the locking frame 10 continues to rotate and cannot push the piston rod of the one-way pneumatic syringe 8. At this time, the piston rod of the one-way pneumatic syringe 8 reversely squeezes the locking frame 10 to slide to the side of the compressed first spring 11, so that the locking frame 10 can pass over the piston rod of the one-way pneumatic syringe 8 when rotating.

[0035] When the right end face of the third sealing ring 7 is worn, the third sealing ring 7 has room to move to the right. At this time, the locking frame 10 can push the piston rod of the one-way pneumatic syringe 8 during rotation, so that the one-way pneumatic syringe 8 can continue to inject gas into the installation tube 3, so that the air pressure in the installation tube 3 remains roughly constant, and under the push of the air pressure, the push frame 6 moves to the right, thereby pushing the third sealing ring 7 to move to the right until the right end face is in close contact with the shell of the petrochemical pump 1 again, so that the third sealing ring 7 can achieve the effect of progressive sealing against wear, so that the third sealing ring 7 is always in close contact between the petrochemical pump 1 and the pump shaft 2, avoiding sealing failure due to wear of the sealing end face, and compared with the method of directly putting a compression spring on the push frame 6 for progressive sealing, the air pressure value of the push frame 6 to move to the right at any time is relatively stable, so that the thrust for pushing the third sealing ring 7 to move to the right is relatively stable, and then the sealing between the right side of the third sealing ring 7 and the shell of the petrochemical pump 1 is relatively stable.

[0036] Embodiment 2: Based on embodiment 1, Figure 5 and Figure 6 As shown, it also includes a card frame 12, which is slidably connected to the side of the rotating frame 9 close to the locking frame 10, and the side of the card frame 12 close to the locking frame 10 is set as an inclined surface, and the card frame 12 is squeezed and matched with the locking frame 10 through the inclined surface, a second spring 13 is fixedly connected between the card frame 12 and the rotating frame 9, and a friction block 14 is fixedly connected to the side of the rotating frame 9 close to the second spring 13, and a friction frame 15 is slidably connected to the side of the card frame 12 close to the friction block 14, and the friction frame 15 contacts the friction block 14, and a third spring 16 is fixedly connected between the card frame 12 and the friction frame 15, and a blocking frame 17 is slidably connected to the side of the card frame 12 away from the friction block 14, and the blocking frame 17 is used to automatically lock the locking frame 10, and the side of the blocking frame 17 close to the locking frame 10 is set as a wedge-shaped surface, and the blocking frame 17 is squeezed and matched with the locking frame 10 through the wedge surface, and a first tension spring 18 is fixedly connected between the card frame 12 and the blocking frame 17.

[0037] Since the pump shaft 2 drives the rotating frame 9 to rotate at a high speed, the locking frame 10 will frequently contact the piston rod of the one-way pneumatic syringe 8 when the third sealing ring 7 is not worn, thereby increasing wear and fatigue and shortening the service life of the locking frame 10 or the one-way pneumatic syringe 8 and other components. Therefore, by extending the reset time of the locking frame 10 and reducing the contact frequency between the locking frame 10 and the piston rod, the specific operation is as follows:

[0038] When the piston rod squeezes the locking frame 10 to slide toward the side of the compressed first spring 11, the locking frame 10 will contact the inclined surface of the adjacent card frame 12 and squeeze the card frame 12 to slide toward the side of the compressed second spring 13. The card frame 12 drives the friction frame 15, the third spring 16, the blocking frame 17 and the first tension spring 18 thereon to move in the same direction. During this process, the third spring 16 in the compressed state gradually resets, so that the friction frame 15 slides along the card frame 12 until it keeps contact with the adjacent friction block 14, and the blocking frame 17 moves until its wedge-shaped surface contacts the adjacent locking frame 10. Then, the locking frame 10 continues to move and squeezes the blocking frame 17 to slide toward the side of the stretched first tension spring 18 until the locking frame 10 is separated from the wedge-shaped surface of the blocking frame 17, and the first tension spring 18 resets and drives the blocking frame 17 to block the locking frame 10, thus achieving the effect of locking the locking frame 10.

[0039] When the piston rod is separated from the locking frame 10, the locking frame 10 no longer squeezes the clamping frame 12. At this time, affected by the friction resistance between the friction block 14 and the friction frame 15, the second spring 13 slowly drives the clamping frame 12 to slide back and forth, so that the blocking frame 17 slowly separates from the locking frame 10, and then the locking frame 10 slowly resets.

[0040] Embodiment 3: Based on embodiment 2, Figure 7 and Figure 8 As shown, it also includes a sealing frame 19, which is slidably connected to the inner right side of the mounting tube 3 along the left and right directions, and the right side of the push frame 6 is provided with exhaust holes 20 evenly distributed along the ring, and the left side of the sealing frame 19 blocks the exhaust holes 20. The right side of the push frame 6 is provided with card holes 21 evenly distributed in the circumferential direction, and the right side of the push frame 6 is provided with an extrusion surface 22. A fourth spring 23 is fixedly connected between the sealing frame 19 and the mounting tube 3, and a circumferentially evenly distributed elastic telescopic block 24 is fixedly connected to the left part of the sealing frame 19. The elastic telescopic block 24 is extruded and matched with the extrusion surface 22, and the elastic telescopic block 24 corresponds to the exhaust holes 20 one by one. Four annularly distributed second tension springs 25 are fixedly connected between the push frame 6 and the tube cover 4.

[0041] like Fig. 9 and Fig.10 As shown, a guide ring 26 is also included. The guide ring 26 is fixed to one side of the installation tube 3 close to the third sealing ring 7. The guide ring 26 contacts the third sealing ring 7. The guide ring 26 guides the medium leaking during disassembly to the discharge pipe 301 through the guide surface 27.

[0042] When disassembling, repairing or cleaning the device, the second sealing ring 601 is easily exposed to the pumping medium, which has a certain degree of contamination. The gas in the left part of the installation tube 3 can be used to blow away the contaminants on the surface of the second sealing ring 601 to reduce the risk of erosion of the second sealing ring 601. The specific operation is as follows:

[0043] When installing the sealing device, first push the push frame 6 to move rightward through the cylinder cover 4. When the extrusion surface 22 contacts the elastic telescopic block 24, the push frame 6 compresses the elastic telescopic block 24 through the extrusion surface 22, and then rotate the cylinder cover 4. The cylinder cover 4 drives the push frame 6 to rotate, so that each clamping hole 21 rotates to correspond to each elastic telescopic block 24, and each elastic telescopic block 24 is reset and clamped into the corresponding clamping hole 21. At this time, the left side of the sealing frame 19 blocks the exhaust hole 20, and during the inflation process, due to the limiting cooperation between the elastic telescopic block 24 and the clamping hole 21, the sealing frame 19 is locked on the push frame 6, so that it cannot be pushed to the right by the air pressure.

[0044] When disassembling the sealing device, the cylinder cover 4 is rotated in the opposite direction, and the cylinder cover 4 drives the push frame 6 to rotate in the opposite direction, so that each elastic telescopic block 24 is squeezed out from the corresponding clamping hole 21. At this time, the lock of the sealing frame 19 is released, and the gas in the left part of the installation cylinder 3 rushes out through the exhaust hole 20. Under the action of air pressure, the sealing frame 19 is opened to the right, and the fourth spring 23 is compressed. The gas rushing out through the exhaust hole 20 is blown to the second sealing ring 601, so that the pollutants on the surface of the second sealing ring 601 are blown to the guide surface 27 of the guide ring 26, and fall downward to the discharge pipe 301 under the action of gravity for discharge. When the gas is exhausted, the fourth spring 23 is reset to drive the sealing frame 19 to slide to the left and reset.

[0045] In the above process, when the push rack 6 moves to the right under the action of air pressure, the second tension spring 25 is gradually stretched. When the seal rack 19 is unlocked, the second tension spring 25 is reset, thereby pulling the push rack 6 to move to the left, so that the space on the left side of the installation tube 3 is compressed and reduced, thereby accelerating the discharge of gas on the left side of the installation tube 3 through the exhaust hole 20, increasing the wind force blowing toward the second sealing ring 601, and improving the decontamination effect.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A mechanical sealing device for a petrochemical pump, characterized in that: The invention comprises a mounting cylinder (3), wherein the mounting cylinder (3) is threadedly connected to a cylinder cover (4), wherein the cylinder cover (4) is provided with a first sealing ring (5) via an annular groove, wherein the cylinder cover (4) is slidably connected to a push frame (6), wherein the inner ring and the outer ring of the push frame (6) are both provided with a second sealing ring (601) via an annular groove, wherein a third sealing ring (7) is provided between an end surface of the push frame (6) away from the cylinder cover (4) and a housing of a petrochemical pump (1), wherein a one-way pneumatic syringe (8) is installed on the mounting cylinder (3), and a rotating frame (9) is bolted to a side of the pump shaft (2) close to the cylinder cover (4), wherein the rotating frame ( 9) is in contact with the cylinder cover (4), the rotating frame (9) is slidably connected with a locking frame (10), the one-way pneumatic syringe (8) is in contact with the locking frame (10), the end surface of the locking frame (10) close to the one-way pneumatic syringe (8) is set as a concave surface, a first spring (11) is fixedly connected between the rotating frame (9) and the locking frame (10), and the pump shaft (2) passes through the rotating frame (9), the cylinder cover (4), the first sealing ring (5), the installation cylinder (3), the pushing frame (6), the second sealing ring (601) of the inner ring and the third sealing ring (7); It also includes a card frame (12), the card frame (12) is slidably connected to a side of the rotating frame (9) close to the locking frame (10), a second spring (13) is fixedly connected between the card frame (12) and the rotating frame (9), a friction block (14) is fixedly connected to the rotating frame (9), a friction frame (15) is slidably connected to one side of the card frame (12), the friction frame (15) is in contact with the friction block (14), a third spring (16) is fixedly connected between the card frame (12) and the friction frame (15), a blocking frame (17) for automatically locking the locking frame (10) is slidably connected to the other side of the card frame (12), and a first tension spring (18) is fixedly connected between the card frame (12) and the blocking frame (17); A side of the card frame (12) close to the locking frame (10) is arranged as an inclined surface, and the card frame (12) is pressed and matched with the locking frame (10) via the inclined surface; A side of the retaining frame (17) close to the locking frame (10) is provided as a wedge-shaped surface, and the retaining frame (17) is pressed and matched with the locking frame (10) via the wedge-shaped surface.

2. A mechanical seal device for a petrochemical pump according to claim 1, characterized in that: The side of the third sealing ring (7) away from the rotating frame (9) is configured in a truncated cone shape, and is used to be wedged into the gap between the pump shaft (2) and the casing of the petrochemical pump (1).

3. A mechanical sealing device for a petrochemical pump according to claim 2, characterized in that: The one-way pneumatic syringe (8) is composed of a syringe barrel, a piston rod, an elastic member, a one-way air inlet pipe and a one-way air outlet pipe. The syringe barrel is fixedly connected to the outer wall of the mounting barrel (3). The piston rod is slidably connected to the syringe barrel. One end of the piston rod close to the locking frame (10) is intermittently in contact with the locking frame (10). The end surface of the piston rod close to the locking frame (10) is arranged as a convex surface. The elastic member is fixedly connected between the piston rod and the inner wall of the syringe barrel. The one-way air inlet pipe is fixedly connected to the top of the syringe barrel. The one-way air outlet pipe is connected between the mounting barrel (3) and the syringe barrel.

4. A mechanical seal device for a petrochemical pump according to claim 3, characterized in that: It also includes a discharge pipe (301), the discharge pipe (301) being connected to a side of the bottom of the installation cylinder (3) close to the third sealing ring (7).

5. A mechanical seal device for a petrochemical pump according to claim 4, characterized in that: The invention also comprises a sealing frame (19), wherein the sealing frame (19) is slidably connected to a side of the mounting tube (3) away from the tube cover (4); a side of the push frame (6) close to the sealing frame (19) is provided with exhaust holes (20) evenly distributed along a ring shape; the sealing frame (19) blocks the exhaust holes (20); a side of the push frame (6) close to the exhaust holes (20) is provided with clamping holes (21) evenly distributed along a circumferential direction; a side of the push frame (6) close to the clamping holes (21) is provided with an extrusion surface (22); a fourth spring (23) is fixedly connected between the sealing frame (19) and the mounting tube (3); the sealing frame (19) is fixedly provided with elastic expansion blocks (24) evenly distributed along a circumferential direction; the elastic expansion blocks (24) are extruded and matched with the extrusion surface (22); and the elastic expansion blocks (24) correspond one to one with the exhaust holes (20).

6. A mechanical seal device for a petrochemical pump according to claim 5, characterized in that: It also includes a second tension spring (25) distributed in an annular shape, wherein the second tension spring (25) is fixedly connected between the push frame (6) and the cylinder cover (4).

7. A mechanical seal device for a petrochemical pump according to claim 6, characterized in that: The invention also includes a guide ring (26), wherein the guide ring (26) is fixedly connected to a side of the installation tube (3) close to the third sealing ring (7), the guide ring (26) is in contact with the third sealing ring (7), and the guide ring (26) guides the leaking medium to the discharge pipe (301) through a guide surface (27).

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