Sealing device for bottom of low-temperature pump well casing in large LNG storage tank

Abstract

The utility model discloses a sealing device for the bottom of a low-temperature pump well casing in a large LNG storage tank, which comprises a pump well casing and a bottom valve plate, the pump well casing is arranged in the LNG storage tank, a low-temperature pump is arranged in the pump well casing, the low-temperature pump is connected through a first steel wire rope, a flange is arranged at the bottom port of the pump well casing, an annular sealing groove is arranged on the flange, and the bottom valve plate is arranged on the bottom port of the pump well casing. A bottom valve plate is arranged at a bottom port of the pump well pipe in a sliding mode, the bottom valve plate moves up and down along the bottom port of the pump well pipe, a protruding ring is arranged on the bottom valve plate, the protruding ring corresponds to the annular sealing groove, the bottom valve plate is connected through a second steel wire rope, and a fixed pulley is rotationally arranged on the outer side of the pump well pipe. The second steel wire rope bypasses the fixed pulley, and a balancing weight is arranged at the end of the second steel wire rope. The utility model aims to provide a sealing device for the bottom of a low-temperature pump well casing in a large LNG (Liquefied Natural Gas) storage tank, so as to overcome the problems in the background technology.

Description

TECHNICAL FIELD

[0001] The utility model relates to sealing technical field, concretely relates to a sealing device for low temperature pump well pipe bottom in large -scale LNG storage tank. BACKGROUND

[0002] LNG in large -scale LNG storage tank at home and abroad needs to carry out pressurization external transmission through submerged cryogenic pump, and the cryogenic pump is installed at the bottom of the pump well pipe, the LNG in the pump well pipe is the ultralow temperature liquid of -162 DEG C, and the sealing device at the bottom of the pump well pipe is in the permanent closed state after the first installation construction of the storage tank is finished, and once a problem occurs, the spare parts of the sealing device cannot be maintained and replaced, therefore, the sealing device at the bottom of the cryogenic pump well is crucial to the operation reliability and safety of the LNG storage tank.

[0003] When the cryogenic pump is taken out from the pump well pipe for maintenance, it is necessary to ensure that the bottom valve at the bottom of the pump well pipe is closed tightly and has no leakage, and the LNG in the storage tank will not leak into the pump well pipe from the bottom of the pump well pipe, the opening and closing of the bottom valve plate at the bottom of the existing pump well pipe is controlled by spring force, when the cryogenic pump is loaded on the bottom valve plate at the bottom of the pump well pipe, the bottom valve plate is pressed downward and opened due to the fact that the gravity of the cryogenic pump is greater than the spring force, and the bottom valve plate is closed when leaving, and the defects existing in this way are that the spring elastic force is uneven, the spring cannot reach the set elastic force value due to the quality or the fact that the service time is too long under the LNG ultralow temperature environment, so that the sealing is not strict, on the other hand, the sealing surface of the bottom valve plate is a plane, when the sealing surface is damaged or there are impurities and foreign matters remaining on the sealing surface, the bottom valve will be closed and the sealing will not be strict, which will lead to the leakage of LNG into the pump well pipe, and cause great safety risk to the maintenance and replacement of the cryogenic pump.

[0004] In view of the technical problem, the utility model provides a sealing device for low temperature pump well pipe bottom in large -scale LNG storage tank. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a sealing device for low temperature pump well pipe bottom in large -scale LNG storage tank, so as to overcome the problems in the background art.

[0006] In order to solve the above technical problems, the utility model adopts the following technical scheme:

[0007] A kind of sealing device for the bottom of cryogenic pump well pipe in large LNG storage tank, including pump well pipe and bottom valve plate, pump well pipe is arranged in LNG storage tank and is provided with cryogenic pump in pump well pipe, cryogenic pump is connected by first wire rope, the flange is arranged at the bottom end port of pump well pipe, and annular sealing groove is arranged on the flange, the bottom valve plate is slidably arranged at the bottom end port of pump well pipe, and the bottom valve plate moves up and down along the bottom end port of pump well pipe, and convex ring is arranged on the bottom valve plate, and the convex ring corresponds to annular sealing groove, the bottom valve plate is connected by second wire rope, and fixed pulley is rotatably arranged outside pump well pipe, and the second wire rope passes through fixed pulley and is provided with counterweight at the end of second wire rope.

[0008] Further, the guide rod is arranged at the edge of the bottom valve plate, and a limit ring is arranged at the top end of the guide rod, a circular hole is arranged on the flange, the guide rod passes through the circular hole, and the end of the second wire rope is connected to the guide rod.

[0009] Further, the number of the guide rod, the second wire rope and the counterweight is 8-12, and the total weight of the counterweight is greater than the weight of the bottom valve plate and less than the weight of the cryogenic pump.

[0010] Further, the pulley connecting rod is arranged outside the pump well pipe, and the fixed pulley is rotatably arranged on the pulley connecting rod, and the number of the fixed pulley is also 8-12.

[0011] Further, the anti-turbulence cylinder body is connected to the pump well pipe by the connecting rod outside the pump well pipe, and the counterweight is located in the anti-turbulence cylinder body.

[0012] Further, the cross section of the convex ring and the annular sealing groove is triangular.

[0013] Compared with the prior art, the utility model can realize at least the following beneficial effects:

[0014] 1. The second wire rope is connected to the bottom valve plate in the utility model, and the counterweight is connected to the end of the second wire rope, the bottom valve plate is pulled upward to seal the pump well pipe by the weight of the counterweight, compared with relying on spring control, the uneven spring force is avoided, the stress is more uniform and reliable, and the sealing effect is facilitated, in addition, the guide rod is arranged on the bottom valve plate, and the guide rod is arranged on the flange at the bottom end of the pump well pipe, so that the movement process of the bottom valve plate is stable.

[0015] 2. The anti-turbulence cylinder body is arranged outside the pump well pipe, and the counterweight is placed in the anti-turbulence cylinder body, which can effectively reduce the disturbance influence of the counterweight when the cryogenic pump operates.

[0016] 3. The bottom of the pump well pipe is provided with a flange, and the annular sealing groove is arranged on the flange, and the flange is arranged on the bottom valve plate, which can prevent foreign matters from staying on the sealing surface and affecting the sealing effect, and greatly increase the sealing contact area, so that the sealing is more tight and solid. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The figure is a structural schematic diagram of the utility model.

[0018] In the figure, 1 is a first steel wire rope, 2 is an LNG storage tank, 3 is a pump well pipe, 4 is a cryogenic pump, 5 is a fixed pulley, 6 is a second steel wire rope, 7 is a counterweight, 8 is an anti-turbulence cylinder, 9 is a flange, 10 is a bottom valve plate, 11 is a guide rod, 12 is a pulley connecting rod, 13 is a connecting rod, 14 is a flange, 15 is a limiting ring, and 16 is an annular sealing groove. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model described and shown in the drawings can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model.

[0021] In the description of the utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0022] Please refer to Figure 1This utility model provides a sealing device for the bottom of a cryogenic pump well pipe in a large LNG storage tank, including a pump well pipe 3 and a bottom valve plate 10. The pump well pipe 3 is installed in the LNG storage tank 2, and a cryogenic pump 4 is installed in the pump well pipe 3 to extract LNG from the pump well pipe 3. The cryogenic pump 4 is connected by a first steel wire rope 1. A flange 14 is provided at the bottom port of the pump well pipe 3. The flange 14 is located outside the bottom port of the pump well pipe 3, and an annular sealing groove 16 is provided on the flange 14. The bottom valve plate 10 is slidably installed at the bottom port of the pump well pipe 3. The bottom valve plate 10 moves up and down along the bottom port of the pump well pipe 3, so that the bottom port of the pump well pipe 3 can be sealed by the bottom valve plate 10. A convex ring 9 is provided on the bottom valve plate 10, and the convex ring 9 corresponds to the annular sealing groove 16. Preferably, the cross-section of the convex ring 9 and the annular sealing groove 16 is triangular. This prevents foreign objects and impurities from remaining on the sealing surface and affecting the sealing effect, and increases the sealing contact area to make the seal tighter and more solid. The bottom valve plate 10 is connected by a second steel wire rope 6. A fixed pulley 5 is rotatably installed on the outside of the pump well pipe 3. The second steel wire rope 6 passes around the fixed pulley 5 and a counterweight 7 is installed at the end of the second steel wire rope 6. The bottom valve plate 10 is lifted by the gravity of the counterweight 7.

[0023] Furthermore, in order to ensure that the bottom valve plate 10 can move up and down stably so that the protruding ring 9 on the bottom valve plate 10 can be aligned and inserted into the annular sealing groove 16, a guide rod 11 is provided at the edge of the bottom valve plate 10 and a limiting ring 15 is provided at the top of the guide rod 11. The limiting ring 15 prevents the guide rod 11 from disengaging from the flange 14. A circular hole is provided on the flange 14, and the guide rod 11 passes through the circular hole. The end of the second steel wire rope 6 is connected to the guide rod 11.

[0024] More specifically, the number of guide rods 11, second wire ropes 6 and counterweights 7 are all 8-12, the specific number of which needs to be determined according to the size of the pump well pipe 3. The total weight of the counterweights 7 is greater than the weight of the bottom valve plate 10 but less than the weight of the cryogenic pump 4, so that the pressure applied by the cryogenic pump 4 can move the bottom valve plate 10 downward, and after the cryogenic pump 4 leaves, the bottom valve plate 10 can be moved upward by the gravity of the counterweights 7.

[0025] In some embodiments, a pulley connecting rod 12 is provided on the outside of the pump well pipe 3, and fixed pulleys 5 are rotatably mounted on the pulley connecting rod 12. The number of fixed pulleys 5 is also 8-12.

[0026] In addition, the outside of the pump well pipe 3 is connected to an anti-turbulence cylinder 8 via a connecting rod 13, and the counterweight 7 is located in the anti-turbulence cylinder 8, thereby effectively reducing the turbulence effect on the counterweight during the operation of the cryogenic pump 4.

[0027] The working process of this utility model is as follows: when the cryogenic pump 4 is lowered to the bottom of the pump well pipe 3 by the first steel wire rope 1, since the mass of the cryogenic pump 4 is greater than the mass of the counterweight 7, the bottom valve plate 10 moves downward and opens, and LNG can enter the pump well pipe 3 through the gap between the pump well pipe 3 and the bottom valve plate 10 to achieve normal operation. When the cryogenic pump 4 is lifted up by the first steel wire rope 1, since the mass of the counterweight 7 is greater than the mass of the bottom valve plate 10, the second steel wire rope 6 will drive the bottom valve plate 10 to be lifted upward, and the bottom of the pump well pipe 3 and the bottom valve plate 10 will be tightly fitted to achieve a seal. Since the cryogenic pump 4 will create turbulence around the bottom of the pump well pipe 3 when it is running, the anti-turbulence cylinder 8 prevents the counterweight 7 from being affected by the turbulence.

[0028] Although the present invention has been described herein with reference to several illustrative embodiments, it should be understood that those skilled in the art can devise many other modifications and implementations that fall within the scope and spirit of the principles disclosed herein. More specifically, various modifications and improvements can be made to the components or layout of the subject matter arrangement within the scope of the disclosure, drawings, and claims. Besides modifications and improvements to the components or layout, other uses will be apparent to those skilled in the art.

Claims

1. A sealing device for the bottom of a cryogenic pump well pipe in a large LNG storage tank, comprising a pump well pipe (3) and a bottom valve plate (10), wherein the pump well pipe (3) is disposed in an LNG storage tank (2) and a cryogenic pump (4) is disposed in the pump well pipe (3), the cryogenic pump (4) being connected by a first steel wire rope (1), characterized in that: A flange (14) is provided at the bottom port of the pump well pipe (3), and an annular sealing groove (16) is provided on the flange (14). A bottom valve plate (10) is slidably provided at the bottom port of the pump well pipe (3). The bottom valve plate (10) moves up and down along the bottom port of the pump well pipe (3), and a convex ring (9) is provided on the bottom valve plate (10). The convex ring (9) corresponds to the annular sealing groove (16). The bottom valve plate (10) is connected by a second steel wire rope (6). A fixed pulley (5) is rotatably provided on the outside of the pump well pipe (3). The second steel wire rope (6) passes around the fixed pulley (5) and a counterweight (7) is provided at the end of the second steel wire rope (6).

2. A sealing device for the bottom of a cryogenic pump well pipe in a large LNG storage tank according to claim 1, characterized in that: A guide rod (11) is provided at the edge of the bottom valve plate (10) and a limit ring (15) is provided at the top of the guide rod (11). A round hole is provided on the flange (14), through which the guide rod (11) passes. The end of the second wire rope (6) is connected to the guide rod (11).

3. A sealing device for the bottom of a cryogenic pump well pipe in a large LNG storage tank according to claim 2, characterized in that: The number of the guide rod (11), the second wire rope (6) and the counterweight (7) are all 8-12, and the total weight of the counterweight (7) is greater than the weight of the bottom valve plate (10) but less than the weight of the cryogenic pump (4).

4. A sealing device for the bottom of a cryogenic pump well pipe in a large LNG storage tank according to claim 1, characterized in that: A pulley connecting rod (12) is provided on the outside of the pump well pipe (3), and fixed pulleys (5) are rotatably mounted on the pulley connecting rod (12). The number of fixed pulleys (5) is also 8-12.

5. A sealing device for the bottom of a cryogenic pump well pipe in a large LNG storage tank according to claim 1, characterized in that: The pump well pipe (3) is connected to an anti-turbulence cylinder (8) via a connecting rod (13) on the outside, and the counterweight (7) is located in the anti-turbulence cylinder (8).

6. A sealing device for the bottom of a cryogenic pump well pipe in a large LNG storage tank according to claim 1, characterized in that: The cross-sections of the convex ring (9) and the annular sealing groove (16) are both triangular.

Images