A method and auxiliary device for fabricating and installing a low dew point piping system

Abstract

This invention relates to a method for manufacturing and installing a low-dew-point nitrogen pipeline system, primarily applicable to rocket engine testing ground processes and other industries requiring high dew point nitrogen, especially in situations where multiple storage containers are used in parallel. By installing auxiliary devices on the storage containers, the cleanliness and dryness of the containers can be effectively controlled, thereby achieving the purpose of transporting low-dew-point nitrogen. The system includes auxiliary devices, storage containers, and delivery pipelines. The storage containers are used to store high-pressure, low-dew-point nitrogen; the auxiliary devices provide positive pressure protection to the storage containers, ensuring the purity and dew point requirements of the nitrogen inside the containers are met with only a small amount of nitrogen, significantly reducing the consumption of high-purity nitrogen during on-site installation, resulting in energy savings, environmental protection, and significant economic benefits. The delivery pipelines supply nitrogen to the storage containers.

Description

Technical Field

[0001] This invention relates to the field of gas transportation, and more specifically to an auxiliary device and method for manufacturing and installing a low dew point pipeline system. Background Technology

[0002] The dew point of a gas is the temperature at which water vapor in the gas begins to condense under specific conditions.

[0003] Low-dew-point high-purity gas pipelines have very high requirements for construction processes and procedures, and each step must be completed strictly according to the corresponding procedures. If any link in the process is flawed or out of control, it can seriously affect the overall quality of the gas, and even the quality of the process products (including purity, dryness, and cleanliness). This necessitates that every step in the construction process of high-purity gas pipelines ensures that the purity of the gas from the gas source remains within the required range by the time it reaches the point of use. Therefore, during the welding process between the storage container and the pipeline, positive pressure protection via an external gas filling device allows for strict control of the dryness and cleanliness of the gas in the storage container during the welding process. Summary of the Invention

[0004] In view of this, the present invention provides an auxiliary device for the fabrication and installation of low dew point nitrogen pipelines to ensure the dryness and cleanliness of nitrogen.

[0005] Before shipment, the storage container is purged with heated nitrogen and sealed with 0.05MPa nitrogen. After arriving at the installation site, it is connected to a low dew point pipeline system to create an installation auxiliary device. This allows the use of only a small amount of nitrogen to ensure the purity of the nitrogen inside the equipment and the final dew point requirements, which can significantly reduce the consumption of high-purity nitrogen during on-site installation.

[0006] Assume the storage container capacity is 20m³ 3 If installed directly, moisture in the air will enter the storage container through free diffusion. Therefore, nitrogen purging and replacement must be performed on-site, requiring approximately 10 purgings (nitrogen consumption approximately 200m³). 3 Only by achieving the required final nitrogen purity and dew point can the necessary conditions be met. However, by using a low-dew-point piping system to fabricate and install auxiliary equipment, only 0.2m of piping is required. 3 (0.05m 3 With continuous nitrogen purging at a flow rate of / h for 4h, the required purity and dew point can be achieved with continuous purging of high-purity nitrogen. This results in significant economic benefits, greatly reducing gas consumption and promoting energy conservation and environmental protection.

[0007] Specifically, before leaving the factory, the container is fitted with inlet and outlet plugs (inlet plug 4 and outlet plug 6). A DN20 opening is pre-drilled on the plug, and a welded pipe nozzle is installed on this opening for connection to the auxiliary inflation device during on-site installation. The welded pipe nozzle can be a Star Arrow Y-series interface, a gas cylinder-specific connector, a compression fitting, a threaded connector, etc., and a matching plug is installed. Attached Figure Description

[0008] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below.

[0009] Figure 1 An installation diagram is provided for the storage container outlet pipeline in this embodiment of the invention.

[0010] Figure 2 This is a diagram of the auxiliary device in an embodiment of the present invention;

[0011] Figure 3 This is a diagram of the venting device in an embodiment of the present invention;

[0012] Figure 4 An installation diagram of the inlet pipeline of the storage container in an embodiment of the present invention is provided. Detailed Implementation

[0013] like Figure 1 The diagram shows: 1. Storage container; 2. Auxiliary device; 3. Inlet flange; 4. Flange blind flange welded connector; 5. Outlet flange; 6. Outlet flange blind flange; 7. Pipeline pre-reserved welded connector; 8. First switching valve; 9. Gas cylinder group; 10. Second switching valve; 11. Pressure regulator inlet pressure measuring point; 12. Pressure regulator; 13. Pressure regulator outlet pressure measuring point; 14. Filter; 15. Venting device; 16. Third switching valve; 17. Fourth switching valve; 18. Check valve; 19. Fifth switching valve.

[0014] The auxiliary device 2 is composed of the following components connected in sequence: gas cylinder group 9, second switch valve 10, pressure regulator inlet pressure measuring point 11, pressure regulator 12, pressure regulator outlet pressure measuring point 13, filter 14, venting device 15, and third switch valve 16.

[0015] The gas cylinder group can be a general-purpose nitrogen cylinder group with a capacity of 15L-50L and a pressure rating of 15-30MPa. The nitrogen purity should be selected according to the purity requirements of the nitrogen in the storage container, and a nitrogen purity of 99.99% or higher is recommended. Pressure measuring point 11 should be selected according to the pressure rating of the gas cylinder group, choosing a pressure measuring point of the same pressure rating within 15-30MPa. Pressure measuring point 13 should be a pressure measuring point with a pressure rating of 0.2MPa.

[0016] The pressure reducing valve should be selected according to the pressure level of the gas cylinder group, with a pressure level of 15-30MPa. It is recommended to use a manual pressure reducing valve made of brass.

[0017] The filter is selected based on the nitrogen purity requirements of the storage container, with a filtration accuracy of 5um-20um.

[0018] The venting device is connected to the main pipeline of auxiliary device 2 via a tee. The venting device consists of a venting hand valve and a check valve. It is generally recommended to select a venting hand valve with a nominal diameter of DN6 and a pressure rating of 10MPa. It is generally recommended to select a check valve with a nominal diameter of DN6 and an opening pressure differential of 0.1MPa.

[0019] Specifically, prefabricated flanged pipes are required, and the pipe flanges are matched with the storage container flanges.

[0020] After wiping each interface clean with a white cloth, connect the gas cylinder group 9, the second switch valve 10, the pressure measuring point 11 of the pressure regulator inlet, the pressure regulating valve 12, the pressure measuring point 13 of the pressure regulator outlet, the filter 14, the venting device 15, and the third switch valve 16 in sequence according to the schematic diagram to form auxiliary device 2.

[0021] Open the hand valve 16, ensure that the pressure reducing valve 12 is completely closed, slowly open the second hand switch valve 10, observe the pressure value shown at the pressure measuring point 11, and confirm that the nitrogen cylinder is full.

[0022] Slowly open the pressure reducing valve 12. The pressure measuring point 13 will start to display the pressure value, and gas flow can be felt at the outlet of the third switch valve 16, which proves that the auxiliary device is working normally. Continue to purge for 10 minutes to clean the pipeline between the gas cylinder group 9 and the third switch valve 16. Plug the pipe opening with a damp white silk cloth and continue to purge until there is no visible excess on the white silk cloth. The purging is then complete.

[0023] If the pressure measuring point 13 does not display a pressure value after the pressure reducing valve 12 is opened to a certain degree, and there is no gas flow at the outlet of the third switch valve 16, then the auxiliary device is faulty. There are three possibilities: 1) The second switch valve 10 or the third switch valve 16 is not open; 2) The third switch valve 16 is not closed; 3) The filter 14 is blocked. The filter 14 should be removed and cleaned. Check in sequence until the fault is eliminated.

[0024] After the white silk cloth inspection is passed, keep the pressure reducing valve 12 open and the outlet of the third switch valve 16 in a state of obvious gas flow. Remove the plug of the welding pipe nozzle 4 on the storage container 1. At this time, there is airflow from the storage container 1 to the outside at the welding pipe nozzle 4. Quickly connect the auxiliary device 2 to the welding pipe nozzle 4 and tighten the joint. It should be noted that the above actions should be completed before the airflow from the welding pipe nozzle 4 disappears.

[0025] Remove the plug at the welded pipe nozzle 6 on the storage container 1. At this time, airflow will flow from the storage container 1 outward through the welded pipe nozzle 6. Open the pressure reducing valve 12 appropriately. The airflow from the storage container 1 outward through the welded pipe nozzle 6 will increase accordingly. When the pressure value displayed at the pressure measuring point 13 is stable at 0.11-0.12MPa, the installation work can begin.

[0026] Remove the blind flanges at the 6 welded pipe joints of storage container 1, and install the prefabricated flanged pipes onto the flanges of storage container 1;

[0027] After the pipeline installation is completed, continue to install the first switch valve 8 on the flange end face of the pipeline outlet;

[0028] The prefabricated flanged pipe and the first switch valve 8 are purged and replaced by manually opening the first switch valve 8 for 10 minutes.

[0029] After the outlet pipeline is installed, close the first switch valve 8;

[0030] Remove the auxiliary device from the storage container inlet. During removal, quickly seal the welded connector 4 with a plug. At this point, the storage container outlet pipe installation is complete.

[0031] Install the blind flange at the other end of the first switch valve 8, connect the gas-filled auxiliary device 2 to the reserved welded pipe nozzle 7 on the pipeline, and begin installing the valve 19 at the inlet end of the storage container 1.

[0032] Turn on the auxiliary device. Airflow will flow from storage container 1 outward from the welding pipe nozzle 4. Open the pressure reducing valve 12 appropriately. The airflow from storage container 1 outward at welding pipe nozzle 4 will increase accordingly. Once the pressure value displayed at pressure measuring point 13 is stable at 0.11-0.12MPa, the installation work can begin.

[0033] Remove the blind flanges at the four welded pipe joints of storage container 1, and install the prefabricated flanged pipes onto the flanges of storage container 1;

[0034] Continue to install the fourth switch valve 19 on the flange face at the other end of the pipeline;

[0035] For systems where storage containers are used in parallel, other storage containers can be installed sequentially following this process.

Claims

1. An installation method for an auxiliary device for fabricating and installing a low dew point pipeline system, used for fabricating and installing low dew point gas transmission pipelines, characterized in that: The device includes storage containers, auxiliary equipment, and delivery pipelines, and is designed for parallel operation of multiple storage containers. Before leaving the factory, the storage containers must have plugs installed at their inlet and outlet. These plugs include an inlet plug and an outlet plug. DN20 openings are pre-drilled on the inlet and outlet plugs of the storage containers, and welded pipe fittings are installed on these openings for connection to the auxiliary equipment during on-site installation. The auxiliary equipment includes a gas cylinder assembly, a second switching valve, a pressure regulator inlet pressure measuring point, a pressure regulator, a pressure regulator outlet pressure measuring point, a filter, a venting device, and a third switching valve. The installation method includes the following steps: After wiping all interfaces clean with a white cloth, connect the gas cylinder group, second switch valve, pressure regulator inlet pressure measuring point, pressure regulator, pressure regulator outlet pressure measuring point, filter, venting device, and third switch valve in sequence to form the auxiliary device. Open the third switch valve to ensure the pressure regulator is completely closed. Slowly open the second switch valve and observe the pressure value shown at the pressure regulator inlet pressure measuring point to confirm that the nitrogen cylinder is full. Slowly open the pressure regulator; the pressure regulator outlet pressure measuring point should start displaying a pressure value, and gas flow should be felt at the outlet of the third switch valve, indicating that the auxiliary device is working normally. Continue purging for 10 minutes to clean the pipeline between the gas cylinder group and the third switch valve. Plug the pipeline with a damp white cloth. Continue purging the pipe until no visible debris is visible on the white cloth. After the white cloth inspection is passed, keep the pressure regulator open and ensure there is a clear gas flow at the outlet of the third switch valve. Remove the plug at the welded connector on the inlet plug plate of the storage container. At this point, airflow should be flowing from the storage container outwards from the welded connector on the inlet plug plate. Quickly connect the auxiliary device to the welded connector on the inlet plug plate and tighten the joint. Remove the plug at the welded connector on the outlet plug plate of the storage container. At this point, airflow should be flowing from the storage container outwards from the welded connector on the outlet plug plate. Increase the pressure regulator opening slightly. The airflow from the storage container outwards from the welded connector on the outlet plug plate should increase accordingly, and the pressure reading on the pressure regulator measuring point should increase. Installation can begin once the pressure reading stabilizes at 0.11-0.12 MPa. Remove the blind flange at the welded nozzle on the storage container outlet plug, and install the prefabricated flanged pipe onto the storage container flange. After pipe installation, install the first switching valve on the flange face at the pipe outlet. Manually open the first switching valve and purge and replace the prefabricated flanged pipe and the first switching valve for 10 minutes. After the outlet pipe installation is complete, close the first switching valve. Remove the auxiliary device from the storage container inlet. During removal, quickly seal the welded nozzle on the inlet plug with a plug. At this point, the storage container outlet pipe installation is complete. Install the blind flange on the other end of the first switching valve. Connect the gas-filled auxiliary device to the pre-reserved welded connector on the pipeline, and begin installing the valve at the inlet end of the storage container. Open the auxiliary device; airflow will flow from the storage container outwards through the welded connector on the inlet plug. Increase the pressure regulator opening appropriately; the airflow from the storage container outwards through the welded connector on the inlet plug will increase accordingly. Once the pressure reading at the pressure regulator outlet is stable at 0.11-0.12 MPa, installation can begin. Remove the blind flange at the welded connector on the inlet plug of the storage container, and install the prefabricated flanged pipeline onto the flange of the storage container. Continue by installing the fourth switch valve on the flange face at the other end of the pipeline. Install other storage containers sequentially according to the above procedure.

Images