Rapid installation structure for multistage centrifugal immersed pump in large-flow high-lift low-temperature tank

Abstract

The utility model discloses a quick mounting structure for a multistage centrifugal immersed pump in a large-flow high-lift low-temperature tank, the large-flow high-lift multistage centrifugal immersed pump is mounted in a pump well, a bottom valve is arranged at the bottom end of the pump well, a plurality of positioning holes are formed in a pump inlet flange, compression springs and positioning balls are arranged in the positioning holes, and the positioning balls are arranged in the positioning holes. A flow guide hole is formed in the side face of the pump inlet flange and communicated with the upper portion of the positioning hole, and a spherical surface positioning clamping groove matched with the positioning ball is formed in the bottom valve. Compared with the prior art, through the design of the quick mounting structure, the pump and the bottom valve are locked through the pressure difference of the high-pressure side and the low-pressure side of the conical sealing surface on the bottom valve and the fixing device when the pump runs, so that the problems of looseness, movement and the like of the conical surfaces of the pump body and the bottom valve caused by large vibration are solved; the problems of fixed installation and stable operation and use of the large-flow and high-lift immersed pump in a pump well are solved, and pressurized conveying can be achieved only through one high-pressure immersed pump.

Description

Technical Field

[0001] The utility model relates to the field of large cryogenic tanks, in particular to a rapid installation structure of a multi-stage centrifugal submersible pump in a large-flow and high-lift cryogenic tank. Background Technique

[0002] As an important development and application direction of cryogenic submersible pumps, with the large-scale application of international cryogenic fluid media (including liquefied natural gas (LNG), liquefied petroleum gas (LPG), liquid ethane, ethylene, liquid air products (such as liquid nitrogen, liquid carbon dioxide, liquid argon, etc.)) and the increasing large-scale storage and transportation, as a key and core cryogenic dynamic equipment, the development of its technology and equipment has been highly valued by various countries. Before 2015, more than 80% of various cryogenic pump products in China relied on imports. However, due to the high price, long supply cycle and difficult-to-meet user requirements of after-sales service of imported products, it has always been a pain point in the construction and operation of end-user projects. After several years of efforts, China has broken through the relevant cryogenic submersible pump technology and completed the full coverage of related industrial chain supporting equipment including in-tank low-pressure pumps and cryogenic multi-stage booster pumps, mainly concentrated in the fields of liquefied natural gas and industrial gases.

[0003] At present, the volume of large liquefied gas cryogenic storage tanks is generally 50,000 - 270,000 cubic meters, the diameter is generally 40 - 110 meters, and the height is generally 35 - 60 meters. The pressurized transportation of liquefied gas in the tank generally adopts the method of "in-tank low-pressure pump + high-pressure out-of-tank booster pump relay", that is, a conventional multi-stage centrifugal submersible pump in the cryogenic tank is installed at the bottom of the tank. The liquefied gas is pressurized to a low pressure of 0.8 - 1 MPaG by this pump, pumped out from the bottom of the tank, transported to the outside of the tank through the top of the tank, and then further pressurized to a high pressure of 5 - 12 MPaG by an out-of-tank high-pressure pump for external transportation to meet the needs of downstream users.

[0004] The height of a conventional multi-stage centrifugal submersible pump in a cryogenic tank is generally 2.3 - 3.2 meters, the weight is generally 1.2 - 2.5 tons, and the flow rate is generally 300 - 2500m 3 / h, with a head of 0.8 - 1 MPaG. It can refer to the submersible pump inside the vertical low-temperature tank, and the patent number is CN201310628806.0. For the conventional multi-stage centrifugal submersible pump inside the low-temperature tank, due to its relatively small head and light weight, its installation is mainly achieved by directly mating the conical surface at the pump inlet with the conical surface of the foot valve. The conical sealing surface on the foot valve serves as the demarcation line. The pump body (including the pump outlet) above the conical sealing surface is the high-pressure area, and the pump inlet below the conical sealing surface is the low-pressure area. The pressure difference between the high and low-pressure areas acts on the valve body and pump body, which can ensure that the sealing surface is in a tightly fitting state and simultaneously plays a role in pressing and fixing. This installation structure has the advantages of simple structure and no need for complex structures and installation bolts. The working mode is that when transporting liquefied gas inside a large liquefied gas low-temperature storage tank, it is necessary to first pump the liquefied gas into a small transfer tank through a low-pressure submersible pump, and then pump it out through the high-pressure booster pump inside the transfer tank to achieve the purpose of pressurized transportation.

[0005] Because our company aims to meet the needs of large liquefied gas low-temperature storage tank application scenarios, through design improvements such as increasing the number of pump stages, we have developed a multi-stage centrifugal submersible pump inside a high-pressure low-temperature tank, which can increase the pressure of the liquefied gas to 5.4 MPaG inside the tank, achieving direct external pressurized transportation without the need for an additional high-pressure pump for transfer and pressurization. It has changed the traditional "low-pressure pump inside the tank + high-pressure booster pump outside the tank relay" method, combining the low-pressure pump and the high-pressure booster pump into one, and realizing a one-pump-through pressurized transportation method.

[0006] Although the pressurization problem has been solved, with the increase in the flow rate and head of the multi-stage centrifugal submersible pump inside the low-temperature tank, the number of pump stages, length, and weight of the pump have all increased rapidly. For example, for a multi-stage centrifugal submersible pump inside a high-pressure low-temperature tank with a flow rate of 342 m 3 / h and a head of 5.4 MPaG for transporting ethylene liquefied gas, its length has increased to 3.6 meters and its weight has reached 4.6 tons. Especially the weight has increased significantly, making the original conventional conical surface installation structure prone to problems such as loosening and movement between the pump body and the conical surface of the foot valve due to large pump vibrations during the operation of the multi-stage centrifugal submersible pump with large flow rate and high head inside the low-temperature tank, posing a great hidden danger to the long-term safe and stable operation of the pump and unable to meet the fixed installation and stable operation requirements of the multi-stage centrifugal submersible pump with large flow rate and high head inside the low-temperature tank. Therefore, our company has carried out further research and design to solve this problem. Utility Model Content

[0007] The purpose of the present utility model is to provide a rapid installation structure for a multi-stage centrifugal submersible pump with large flow rate and high head inside a low-temperature tank that solves the above problems.

[0008] To achieve the above object, the technical solution adopted by the utility model is: a rapid installation structure of a multi-stage centrifugal submersible pump with large flow and high head in a low-temperature tank, including a large low-temperature tank, a pump well is arranged in the large low-temperature tank, a bottom valve is arranged at the bottom end of the pump well, a multi-stage centrifugal submersible pump with large flow and high head is installed in the pump well, the multi-stage centrifugal submersible pump is composed of a pump body and a pump inlet flange, a plurality of positioning holes are vertically opened on the end surface of the pump inlet flange, positioning balls and compression springs are installed in the positioning holes, a diversion hole is opened on the side surface of the pump inlet flange, the diversion hole is communicated with the upper part of the positioning hole, a conical sealing surface matching the pump inlet flange is opened on the bottom valve, and a spherical positioning slot matching the positioning ball is opened on the conical sealing surface.

[0009] Preferably, the lower end opening of the positioning hole is a tapered opening, and the diameter of the tapered opening is smaller than the diameter of the positioning ball.

[0010] Preferably, the number of the positioning holes is 6 to 12, and the positioning holes are evenly spaced along the circumferential direction of the pump inlet flange.

[0011] Preferably, the number of the diversion holes is the same as the number of the positioning holes, and the diversion holes are respectively communicated with the positioning holes.

[0012] Preferably, a retaining strip for limiting the lower end of the pump inlet flange is arranged in the liquid inlet of the bottom valve.

[0013] Compared with the prior art, the advantages of the utility model are as follows:

[0014] (1) The utility model solves the problems of fixed installation and stable operation of the submersible pump with large flow and high head in the pump well, which is beneficial to realize pressurized transportation with only one pump in the tank, changes the common relay form transportation mode of "low-pressure pump in the tank + booster pump outside the tank", simplifies the system, and reduces the comprehensive energy consumption of the system (including construction and operation links); simplifies the operation, makes the whole system more reliable, and thus extends the overhaul interval period of key equipment.

[0015] (2) Through the design of the rapid installation structure, the utility model solves the problem of insufficient connection stability caused by only relying on the conical surface structure when the flow is large and the head is high. When the pump is running, the pressure difference between the high-pressure side and the low-pressure side of the conical sealing surface and the fixing device lock the pump and the bottom valve, overcome the problems such as loosening and movement of the conical surface between the pump body and the bottom valve caused by large vibration, increase the running stability of the pump, and ensure the safe operation of the pump. This structure can also be disassembled conveniently and quickly. When disassembly is required, stop the operation of the pump, the pressure difference between the high-pressure side and the low-pressure side of the conical sealing surface disappears, and it can be disassembled by means of the resilience of the compression spring, and can be disassembled conveniently and quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a schematic assembly diagram of the present utility model on a multistage centrifugal submerged pump in a large low-temperature tank pump well;

[0017] Figure 2 This is a schematic assembly structure diagram of the present utility model between a multistage centrifugal submerged pump and a bottom valve at the bottom of a pump well;

[0018] Figure 3 This is a schematic end face structure diagram of the bottom valve of the present utility model.

[0019] In the figure: 1. Large low-temperature tank; 2. Pump well; 3. Multistage centrifugal submerged pump; 4. Bottom valve; 41. Conical sealing surface; 42. Spherical positioning card slot; 5. Pump inlet flange; 6. Bar; 7. Positioning hole; 8. Compression spring; 9. Positioning ball; 10. Flow guiding hole. Specific embodiments

[0020] The improved installation structure is beneficial to improving the fixed installation and operation stability of the multistage centrifugal submerged pump in a large-flow low-temperature tank after increasing the head. For example, the head of the multistage centrifugal submerged pump is increased from 0.8 - 1 MPaG to 5.4 MPaG. Without the need for an external high-pressure pump for boosting and transportation, to increase the flow rate and head of the multistage centrifugal submerged pump 3 in the low-temperature tank, it is necessary to increase the number of pump stages, resulting in a rapid increase in the weight of the pump, from 1.2 - 2.5 tons to 4.6 tons, thus leading to a significant reduction in stability. When the original conventional conical surface installation structure is in operation, it is very unstable and prone to problems such as loosening and displacement between the lower end of the pump body and the conical surface of the bottom valve 4 due to large vibrations of the pump. Therefore, the present utility model designs a rapid installation structure for the centrifugal submerged pump 3 in the large low-temperature tank 1 to solve the operation stability problem of the multistage centrifugal submerged pump 3 with large flow rate and high head in the low-temperature tank, thereby ensuring the fixed installation and safe and stable operation of the pump.

[0021] The following will further illustrate the present utility model. Refer to Figure 1 、 Figure 2 and Figure 3, A rapid installation structure for a centrifugal submersible pump 3 inside a large cryogenic tank 1, comprising a large cryogenic tank 1. A pump well 2 is provided inside the large cryogenic tank 1. A bottom valve 4 is provided at the bottom end of the pump well 2. A multi-stage centrifugal submersible pump 3 with a large flow rate and high head is installed inside the pump well 2. The multi-stage centrifugal submersible pump 3 is composed of a pump body and a pump inlet flange 5. A plurality of positioning holes 7 are vertically opened on the pump inlet flange 5. The number of the positioning holes 7 is 6 to 12, and the positioning holes 7 are evenly spaced along the circumferential direction of the pump inlet flange 5. Compression springs 8 and positioning balls 9 are provided in each of the positioning holes 7. A diversion hole 10 is opened on the side surface of the pump inlet flange 5, and the diversion hole 10 communicates with the upper part of the positioning hole 7. The number of the diversion holes 10 is the same as that of the positioning holes 7 and they communicate with the respective positioning holes 7. A conical sealing surface 41 matching the pump inlet flange 5 is opened on the bottom valve 4, and a spherical positioning slot 42 matching the positioning ball 9 is opened on the conical sealing surface 41. Through the structural design of the positioning holes 7, diversion holes 10, compression springs 8 and positioning balls 9, in the operation of the pump, the pressure difference between the high-pressure side and the low-pressure side of the conical sealing surface 41 on the bottom valve 4 is used to lock the pump inlet flange 5 and the bottom valve 4 by the fixing device, overcoming problems such as loosening and movement of the pump body and the conical surface of the bottom valve 4 caused by large vibration, increasing the operation stability of the pump and ensuring the safe operation of the pump. This structure can achieve convenient and quick disassembly. When disassembly is required, stop the operation of the pump, the pressure difference between the high-pressure side and the low-pressure side of the conical sealing surface 41 disappears, and disassembly can be achieved by means of the resilience of the spring, realizing convenient and quick disassembly.

[0022] The lower end opening of the positioning hole 7 is a tapered opening, and the diameter of its tapered opening is smaller than the diameter of the positioning ball 9, which can limit the positioning ball 9 in the positioning hole 7 and prevent the positioning ball 9 from falling off from the lower end of the positioning hole 7.

[0023] A stop bar 6 for limiting the lower end of the pump inlet flange 5 is provided inside the liquid inlet of the bottom valve 4. When hoisting the multi-stage centrifugal submersible pump 3, the stop bar 6 can play a positioning and guiding role, so that the pump inlet flange 5 of the multi-stage centrifugal submersible pump 3 can be inserted more accurately into the liquid inlet of the bottom valve 4. Although the stop bar 6 is a conventional structure, the present invention can achieve the alignment of the positioning ball 9 and the spherical positioning slot 42 by means of the stop bar 6.

[0024] During pump installation: Since there is no liquid in the pump well, when hoisting the pump to the conical surface of the bottom valve 4 in the pump well 2, it is necessary to adjust the orientation of the pump so that the position of the positioning ball 9 is aligned with the spherical positioning slot 42 of the bottom valve 4, thereby achieving precise positioning during pump installation. Although the positioning ball 9 is stuck in the spherical positioning slot 42, the pressure of the spring is not yet sufficient to completely lock the positioning ball 9 in the spherical positioning slot 42, and the pump and the bottom valve 4 are still loose and can move.

[0025] When the pump is running: A high pressure will be formed in the pump well 2. Since the pressure above the conical sealing surface 41 is greater than the pressure below the conical sealing surface 41, the high-pressure liquid acts on the back of the positioning ball 9 through the diversion hole 10, pressing the positioning ball 9 tightly. Only at this time can the complete locking of the positioning ball 9 and the spherical positioning card slot 42 be achieved, and the pump and the foot valve 4 are completely locked to ensure that the whole pump and the foot valve 4 are clamped tightly during the operation of the unit, and problems such as the loosening and movement of the conical surface between the pump body and the foot valve 4 due to the large vibration of the pump, as well as the leakage problem between the high-pressure and low-pressure areas, are avoided. Through this structure, the problem of insufficient connection stability caused by the original structure relying only on the conical surface structure is solved, so that the multistage centrifugal submersible pump 3 with increased flow and head can lock the pump and the foot valve 4 through the pressure difference between the high-pressure and low-pressure sides and the positioning ball 9 during operation.

[0026] When disassembly is required: Stop the operation of the pump, the pressure difference between the high-pressure and low-pressure sides of the conical sealing surface 41 of the foot valve 4 disappears, and with the help of the resilience of the compression spring 8, the release of the positioning ball 9 from the spherical positioning card slot 42 can be completed, and the quick disassembly of the pump can be easily achieved.

[0027] The above has introduced in detail a quick installation structure and process of a multistage centrifugal submersible pump in a large-flow high-head low-temperature tank provided by the present utility model. Specific examples are used in this article to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model; at the same time, for those of ordinary skill in the art, according to the idea of the present utility model, there will be changes in the specific implementation manner and application scope. It is possible to make changes and improvements to the present utility model without exceeding the concept and scope defined by the appended claims. In summary, the content of this specification should not be construed as a limitation to the present utility model.

Claims

1. A quick installation structure for a multi-stage centrifugal submersible pump in a large flow and high head cryogenic tank, comprising a large cryogenic tank, a pump well is arranged in the large cryogenic tank, a bottom valve is arranged at the bottom end of the pump well, and a multi-stage centrifugal submersible pump with a large flow and high head is installed in the pump well, characterized in that: The multi-stage centrifugal submersible pump consists of a pump body and a pump inlet flange. A plurality of positioning holes are vertically opened on the end surface of the pump inlet flange. Positioning balls and compression springs are installed in the positioning holes. A guide hole is opened on the side of the pump inlet flange. The guide hole is connected to the upper part of the positioning hole. A conical sealing surface matching the pump inlet flange is opened on the bottom valve. A spherical positioning groove matching the positioning ball is opened on the conical sealing surface.

2. According to claim 1, a quick installation structure for a multi-stage centrifugal submersible pump in a cryogenic tank with a large flow rate and a high lift, characterized in that: The lower opening of the positioning hole is a gradually shrinking opening, and the diameter of the gradually shrinking opening is smaller than the diameter of the positioning ball.

3. According to claim 1, a quick installation structure for a multi-stage centrifugal submersible pump in a cryogenic tank with a large flow rate and a high lift, characterized in that: The number of the positioning holes is 6 to 12, and the positioning holes are evenly spaced and distributed along the circumference of the pump inlet flange.

4. According to claim 1, a quick installation structure for a multi-stage centrifugal submersible pump in a cryogenic tank with a large flow rate and a high lift, characterized in that: The number of the guide holes is the same as the number of the positioning holes, and the guide holes are respectively connected to the positioning holes.

5. According to claim 1, a quick installation structure for a multi-stage centrifugal submersible pump in a cryogenic tank with a large flow rate and a high lift, characterized in that: A stop bar is arranged in the liquid inlet of the bottom valve to limit the lower end of the pump inlet flange.

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