Shifting fork type corrugated pipe mechanical sealing device for ultra-low-temperature pump

Abstract

The utility model discloses a shifting fork type corrugated pipe mechanical sealing device for an ultra-low-temperature pump, which relates to the field of mechanical sealing of cryogenic low-temperature pumps and comprises a corrugated pipe, two groups of sealing mechanisms are fixedly connected to one end of the corrugated pipe, and a connecting mechanism is fixedly connected to the outer wall of each sealing mechanism. By arranging the sealing mechanism, when the two sets of corrugated pipes are not connected, the sealing columns block the connecting pipes, the corrugated pipes can be protected, dust and other impurities can be prevented from entering the corrugated pipes, after the two sets of connecting pipes are connected, the sealing columns give way, media can enter the corrugated pipes through the connecting pipes, and meanwhile when the two sets of connecting pipes are disengaged, the sealing columns are prevented from falling off. The sealing column resets to block the connecting pipe, medium circulation is stopped in time, large-amount leakage of the medium is prevented, and safety is improved; the connecting mechanism can quickly connect and fix the two sets of connecting pipes, and meanwhile the sealing performance of the corrugated pipe in the using process is enhanced.

Description

Technical Field

[0001] The utility model relates to the field of cryogenic low-temperature pump mechanical seals, and specifically to a fork-type bellows mechanical seal device for cryogenic pumps. Background Art

[0002] Cryogenic low-temperature pumps are special cryogenic pumps for transporting liquefied petroleum natural gas, liquid hydrocarbons, liquid oxygen, and liquid nitrogen. With the rapid development of the energy industry and petrochemical industry, cryogenic liquids are widely used in various chemical and technological processes. As a key equipment in the process device, we used to rely entirely on imports. In recent years, domestic enterprises have begun to get involved in the development of cryogenic low-temperature pumps. Among them, the vast majority of the key component, the welded metal bellows mechanical seal, is provided by France and the United States.

[0003] However, the existing technology has the following disadvantages: Since the medium transported by the cryogenic low-temperature pump is a liquid that is phase-changed from a gas through physical means (in a liquid state at about -190°C), in an extremely low-temperature environment of -196°C, the lubricity of the liquid fluid is very poor, and the hardness and friction coefficient of the metal and non-metal materials for making mechanical seals increase. When the cryogenic low-temperature pump is working, the liquid fluid near the sealing surface is heated due to the friction and agitation generated during the operation of the mechanical seal, showing a vaporization trend and increasing pressure, causing the metal bellows to bear an increased torque; when the torque borne by the metal bellows at high speed exceeds the bearing strength of the metal at this temperature, the bellows may break, and this phenomenon occurs frequently. The occurrence of the above phenomenon will cause the transported medium to directly enter the environment and instantaneously expand into a gas with a sharp increase in volume, causing an explosion, accompanied by combustion, toxicity, etc., posing a huge threat to safety and the environment. Therefore, the working reliability of the mechanical seal is crucial.

[0004] The existing patent (publication number: CN 204187014 U), a fork-type bellows mechanical seal device for cryogenic pumps, includes a fork-type bellows mechanical seal device for cryogenic pumps, which enables the torque borne by the bellows assembly to be transmitted to the stationary ring seat, so that the bellows will not break. The two sides of the inner step of the stationary ring seat and the end face of the boss B form a bellows axial displacement space. During installation, the bellows is compressed to provide the closing force of the mechanical seal. During operation, the boss B is axially limited by the step of the stationary ring seat to cope with the evacuation and blockage caused by the heat of the transported liquefied fluid.

[0005] However, the above patent still has certain defects. When loosening or detachment occurs at the bellows connection, a large amount of cryogenic medium will flow out from the connection, resulting in resource loss. At the same time, due to the extremely low temperature of the medium, it is easy to cause damage to surrounding items and pose a danger. Summary of the Utility Model

[0006] Based on this, the purpose of the present utility model is to provide a fork-type bellows mechanical seal device for cryogenic pumps to solve the technical problems raised in the above background.

[0007] To achieve the above object, the present utility model provides the following technical solutions: A fork-type bellows mechanical seal device for cryogenic pumps, including a bellows, one end of the bellows is fixedly connected with a sealing mechanism, the outer wall of the sealing mechanism is fixedly connected with a connecting mechanism, and there are two groups of the sealing mechanisms; the sealing mechanism includes a connecting pipe fixedly connected with one end of the bellows, a circular groove is opened inside the connecting pipe, a cryogenic spring is fixedly connected in the groove of the circular groove, one end of the cryogenic spring is fixedly connected with a sealing column, a limiting ring is fixedly sleeved on the inner wall of the connecting pipe, a push bar is slidably connected in the inner ring of the limiting ring, and a baffle is fixedly connected inside the connecting pipe.

[0008] As a preferred technical solution of the present utility model, both the push bar and the baffle are provided with four groups, and the four groups of push bars and baffles are arranged in a circumferential array with the cryogenic spring as the axis. The push bar is fixedly connected between a group of sealing columns and is in contact with another group of sealing columns.

[0009] As a preferred technical solution of the present utility model, a connecting mechanism is fixedly connected to the outer wall of the connecting pipe. One end of the connecting pipe is fixedly connected with a sealing plate, and a sealing groove is opened on the connecting pipe. The sealing groove is slidably connected with the sealing plate, and both the sealing plate and the sealing groove are provided with two groups.

[0010] As a preferred technical solution of the present utility model, the connecting mechanism includes a first fixing ring fixedly connected to the outer wall of a group of connecting pipes. A rack ring is rotatably connected to the outside of the first fixing ring. A gear is meshed inside the rack ring. The gear is rotatably connected between the first fixing ring. A threaded rod is threadedly connected to the inner wall of the gear. A second fixing ring is fixedly connected to the outer wall of the other group of connecting pipes, and a connecting component is opened on the second fixing ring.

[0011] As a preferred technical solution of the present utility model, the connecting component includes an arc-shaped groove opened on the second fixing ring. An arc-shaped piston plate is slidably connected in the groove of the arc-shaped groove. A hydraulic groove is opened on the second fixing ring. The hydraulic groove is communicated with the arc-shaped piston plate. A circular piston plate is slidably connected in the groove of the hydraulic groove. The circular piston plate is fixedly connected with the threaded rod.

[0012] As a preferred technical solution of the present utility model, there are four groups of the circular piston plates, hydraulic grooves, gears and threaded rods, and the four groups of circular piston plates, hydraulic grooves, gears and threaded rods are arranged in a circumferential array with the arc-shaped piston plate as the axis.

[0013] As a preferred technical solution of the present utility model, a clamping groove is provided on the first fixing ring, an arc-shaped plate is slidably connected in the clamping groove, and an arc-shaped piston plate is fixedly connected to the bottom end of the arc-shaped plate.

[0014] In summary, the present utility model mainly has the following beneficial effects:

[0015] By setting the sealing mechanism, when the two bellows are not connected, the sealing column blocks the connecting pipe, which can protect the inside of the bellows and prevent impurities such as dust from entering. After the two connecting pipes are connected, the sealing column gives way, and the medium can enter the bellows through the connecting pipe. At the same time, when the two connecting pipes are separated, the sealing column resets to block the connecting pipe, timely stopping the flow of the medium and preventing a large amount of leakage of the medium, improving safety; the connecting mechanism can quickly connect and fix the two connecting pipes, and at the same time enhance the sealing performance of the bellows during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the overall structure of the present utility model;

[0017] Figure 2 is a schematic diagram of the internal structure of the present utility model;

[0018] Figure 3 is the present utility model Figure 2 an enlarged view of part A in.

[0019] In the figure: 100, bellows; 200, sealing mechanism; 300, connecting mechanism; 400, sealing plate; 500, sealing groove;

[0020] 210, connecting pipe; 220, circular groove; 230, low-temperature spring; 240, sealing column; 250, limiting ring; 260, push bar; 270, baffle;

[0021] 310, first fixing ring; 320, rack ring; 330, gear; 340, threaded rod; 350, connecting component; 360, arc-shaped plate; 370, clamping groove; 380, second fixing ring;

[0022] 351, circular piston plate; 352, hydraulic groove; 353, arc-shaped groove; 354, arc-shaped piston plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present utility model and should not be construed as limiting the present utility model.

[0024] The embodiments of the present utility model will be described below according to its overall structure.

[0025] A fork-type bellows mechanical seal device for an ultra-low temperature pump, as Figures 1 to 3 shown, includes a bellows 100. One end of the bellows 100 is fixedly connected to a sealing mechanism 200. The outer wall of the sealing mechanism 200 is fixedly connected to a connecting mechanism 300. Two sets of the sealing mechanisms 200 are provided. The sealing mechanism 200 includes a connecting pipe 210 fixedly connected to one end of the bellows 100. A circular groove 220 is formed inside the connecting pipe 210. A low-temperature spring 230 is fixedly connected to the groove of the circular groove 220. One end of the low-temperature spring 230 is fixedly connected to a sealing column 240. A limiting ring 250 is fixedly sleeved on the inner wall of the connecting pipe 210. A push bar 260 is slidably connected to the inner ring of the limiting ring 250. A baffle 270 is fixedly connected to the inner side of the connecting pipe 210. Four sets of the push bars 260 and the baffles 270 are provided. The four sets of the push bars 260 and the baffles 270 are arranged in a circumferential array with the low-temperature spring 230 as the axis. The push bar 260 is fixedly connected between a set of sealing columns 240 and is in contact with another set of sealing columns 240. The outer wall of the connecting pipe 210 is fixedly connected to a connecting mechanism 300. One end of the connecting pipe 210 is fixedly connected to a sealing plate 400. A sealing groove 500 is formed in the connecting pipe 210. The sealing plate 400 is slidably connected to the sealing groove 500. Two sets of the sealing plates 400 and the sealing grooves 500 are provided.

[0026] When connecting two groups of bellows 100, the pushing bar 260 is inserted inside a group of limiting rings 250, and a group of sealing columns 240 are pushed to move into the connecting pipe 210, thereby driving the low-temperature spring 230 to be compressed. The sealing column 240 that was originally tightly attached to the inner ring of the limiting ring 250 moves into a group of connecting pipes 210. When the sealing column 240 moves to fit with the baffle 270, the connecting pipe 210 can no longer move. At this time, the pushing bar 260 pushes a group of sealing columns 240 fixedly connected to it to move into the other group of connecting pipes 210, and drives the low-temperature spring 230 connected to this group of sealing columns 240 to be compressed. At this time, the medium between the two groups of bellows 100 can flow. When the two groups of bellows 100 move away from each other, driving the two groups of connecting pipes 210 to move away from each other, the two low-temperature springs 230 reset to drive the two sealing columns 240 to fit with the inner ring of the limiting ring 250 again, preventing the medium from flowing out of the connecting pipe 210. A sealing strip can be provided at the fitting position between the inner ring of the limiting ring 250 and the sealing column 240, so that it is more difficult for the medium to flow out of the connecting pipe 210 after the sealing column 240 fits with the limiting ring 250; when the two groups of connecting pipes 210 approach each other, the sealing plate 400 is driven to insert into the sealing groove 500. When one end of the two groups of connecting pipes 210 is completely fitted, the sealing plate 400 is completely inserted into the sealing groove 500 to prevent the medium from flowing out of the connecting pipe 210.

[0027] Please refer specifically to Figure 3 , the connecting mechanism 300 includes a first fixing ring 310 fixedly connected to the outer wall of a group of connecting pipes 210. A rack ring 320 is rotatably connected to the outside of the first fixing ring 310. A gear 330 is engaged with the inside of the rack ring 320. The gear 330 is rotatably connected to the first fixing ring 310. A threaded rod 340 is threadedly connected to the inner wall of the gear 330. A second fixing ring 380 is fixedly connected to the outer wall of the other group of connecting pipes 210. A connecting component 350 is provided on the second fixing ring 380; the connecting component 350 includes an arc-shaped groove 353 opened on the second fixing ring 380. An arc-shaped piston plate 354 is slidably connected to the groove of the arc-shaped groove 353. A hydraulic groove 352 is opened on the second fixing ring 380. The hydraulic groove 352 communicates with the arc-shaped piston plate 354. A circular piston plate 351 is slidably connected to the groove of the hydraulic groove 352. The circular piston plate 351 is fixedly connected to the threaded rod 340; the circular piston plate 351, the hydraulic groove 352, the gear 330, and the threaded rod 340 are all provided in four groups. The four groups of circular piston plates 351, hydraulic grooves 352, gears 330, and threaded rods 340 are circumferentially arranged in an array with the arc-shaped piston plate 354 as the center; a clamping groove 370 is opened on the first fixing ring 310. An arc-shaped plate 360 is slidably connected to the groove of the clamping groove 370. The bottom end of the arc-shaped plate 360 is fixedly connected to the arc-shaped piston plate 354.

[0028] After inserting the threaded rod 340 into the inside of the gear 330, rotate the rack ring 320 to drive the gear 330 to rotate. Since the inner wall of the gear 330 is provided with threads matching the outer wall of the threaded rod 340, and at the same time, the circular piston plate 351 is slidably connected to the hydraulic groove 352, the threaded rod 340 cannot rotate. Thus, the rotation of the gear 330 drives the threaded rod 340 to slide on the inner wall of the first fixing ring 310, and then drives the first fixing ring 310 to approach the second fixing ring 380. When the first fixing ring 310 and the second fixing ring 380 are in contact, continue to rotate the rack ring 320 to drive the threaded rod 340 to slide within the first fixing ring 310, thereby pushing the circular piston plate 351 to move into the hydraulic groove 352, and then driving the hydraulic oil in the hydraulic groove 352 into the arc groove 353. The hydraulic oil in the arc groove 353 increases, pushing the arc piston plate 354 to move outward within the arc groove 353, thereby driving the arc plate 360 to insert into the card slot 370, and preventing the medium from flowing out of the connecting pipe 210 again. This is the principle of the existing hydraulic jack. And during the medium transmission process, since the temperature of the medium is extremely low and the hydraulic oil is solidified, at this time, neither the circular piston plate 351 nor the arc piston plate 354 can move, making the fixing of the connecting mechanism 300 between the two connecting pipes 210 more firm. After the transmission ends, the normal temperature hydraulic oil can be thawed. Reverse the rack ring 320 to drive the first fixing ring 310 and the second fixing ring 380 to move away from each other, thereby releasing the connection between the two connecting pipes 210. The parts not involved in this device are the same as the prior art or can be implemented using the prior art.

[0029] Although the embodiments of the present invention have been shown and described, the specific embodiments are only explanations of the present invention and not limitations thereof. The specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art can, without departing from the principle and purpose of the present invention, make modifications, substitutions and variations that do not contribute creatively to the embodiments as needed. However, as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. The fork-type bellows mechanical seal device for cryogenic pumps, including a bellows (100), is characterized in that: One end of the corrugated pipe (100) is fixedly connected with a sealing mechanism (200), the outer wall of the sealing mechanism (200) is fixedly connected with a connecting mechanism (300), and two groups of the sealing mechanisms (200) are provided. The sealing mechanism (200) includes a connecting pipe (210) fixedly connected with one end of the corrugated pipe (100). A circular groove (220) is formed inside the connecting pipe (210). A low-temperature spring (230) is fixedly connected inside the circular groove (220). One end of the low-temperature spring (230) is fixedly connected with a sealing column (240). A limiting ring (250) is fixedly sleeved on the inner wall of the connecting pipe (210). A push bar (260) is slidably connected to the inner ring of the limiting ring (250). A baffle (270) is fixedly connected to the inner side of the connecting pipe (210).

2. The fork-type bellows mechanical seal device for an ultra-low temperature pump according to claim 1, characterized in that: Four groups of the push bars (260) and the baffles (270) are provided. The four groups of the push bars (260) and the baffles (270) are arranged in a circumferential array with the low-temperature spring (230) as the axis. The push bar (260) is fixedly connected between a group of sealing columns (240), and the push bar (260) is in contact with another group of sealing columns (240).

3. The fork-type bellows mechanical seal device for cryogenic pumps according to claim 1, characterized in that: The outer wall of the connecting pipe (210) is fixedly connected with a connecting mechanism (300). One end of the connecting pipe (210) is fixedly connected with a sealing plate (400). A sealing groove (500) is formed in the connecting pipe (210). The sealing plate (400) is slidably connected with the sealing groove (500), and two groups of the sealing plates (400) and the sealing grooves (500) are provided.

4. The forked bellows mechanical seal device for cryogenic pumps according to claim 3, characterized in that: The connecting mechanism (300) includes a first fixing ring (310) fixedly connected with the outer wall of a group of connecting pipes (210). A rack ring (320) is rotatably connected to the outside of the first fixing ring (310). A gear (330) is meshed with the inner side of the rack ring (320). The gear (330) is rotatably connected with the first fixing ring (310). A threaded rod (340) is threadedly connected to the inner wall of the gear (330). The outer wall of the other group of connecting pipes (210) is fixedly connected with a second fixing ring (380). A connecting component (350) is formed in the second fixing ring (380).

5. The forked bellows mechanical seal device for cryogenic pumps according to claim 4, characterized in that: The connecting component (350) includes an arc-shaped groove (353) formed in the second fixing ring (380). An arc-shaped piston plate (354) is slidably connected to the inside of the arc-shaped groove (353). A hydraulic groove (352) is formed in the second fixing ring (380). The hydraulic groove (352) is communicated with the arc-shaped piston plate (354). A circular piston plate (351) is slidably connected to the inside of the hydraulic groove (352). The circular piston plate (351) is fixedly connected with the threaded rod (340).

6. The fork type bellows mechanical seal device for cryogenic pumps according to claim 5, characterized in that: The circular piston plates (351), hydraulic grooves (352), gears (330), and threaded rods (340) are all provided in four groups, and the four groups of circular piston plates (351), hydraulic grooves (352), gears (330), and threaded rods (340) are arranged in a circumferential array with the arc-shaped piston plate (354) as the axis.

7. The fork-type bellows mechanical seal device for an ultra-low temperature pump according to claim 5, characterized in that: A clamping groove (370) is formed on the first fixing ring (310), an arc-shaped plate (360) is slidably connected in the clamping groove (370), and the bottom end of the arc-shaped plate (360) is fixedly connected with an arc-shaped piston plate (354).

Images