[0017] The present invention provides a liquid nitrogen delivery pipeline for preventing water hammer, which includes a liquid nitrogen tank self-pressurization and pressure relief pipeline, a liquid nitrogen delivery pipeline, a liquid nitrogen mist generating device, a gas-liquid separation device; and a liquid nitrogen tank self-pressurization And the pressure relief pipeline through the self-pressurization method to control the pressure of the liquid nitrogen tank to provide system pressure for the liquid nitrogen delivery pipeline; the liquid nitrogen delivery pipeline establishes the passage between the liquid nitrogen tank and the liquid nitrogen mist generating device, through the stop valve, The regulating valve realizes the control and adjustment of pipeline flow; the liquid nitrogen mist generating device produces various spray special effects; the gas-liquid separation device distinguishes the gas-liquid two-phase in the liquid nitrogen pipeline, and discharges the gaseous nitrogen in the pipeline to ensure delivery The terminal liquid nitrogen mist generating device is single-phase liquid nitrogen.
[0018] The liquid nitrogen tank pressurization and pressure relief pipeline includes a liquid nitrogen tank 1, a first manual stop valve 2, a first regulating valve 3, a vaporizer 4, a second manual stop valve 5, a third manual stop valve 6, a Second regulating valve 7, muffler 8; the bottom of the liquid nitrogen tank 1 is connected to one end of the first manual stop valve 2, and the other end of the first manual stop valve 2 is connected to the first regulating valve 3, the vaporizer 4, and the second manual Stop valve 5, the other end of the second manual stop valve 5 is simultaneously connected to the top of the liquid nitrogen tank 1, one end of the third manual stop valve 6, and one end of the second regulating valve 7. Both ends of the third manual stop valve 6 are connected to the first After the two regulating valves 7 are connected in parallel, they are connected to one end of the muffler 8, and the other end of the muffler 8 is connected to the air.
[0019] The liquid nitrogen delivery pipeline includes a fourth manual shut-off valve 9, an emergency shut-off valve 10, a filter 11, a flow meter 12, and a third regulating valve 13. The bottom of the liquid nitrogen tank 1 is connected to one end of the fourth manual shut-off valve 9. The other end of the fourth manual shut-off valve 9 is sequentially connected to the emergency shut-off valve 10, the filter 11, the flow meter 12, and the third regulating valve 13. The other end of the third regulating valve 13 is simultaneously connected with the gas-liquid separator 14, the liquid nitrogen generator The mist device 19 is connected.
[0020] The gas-liquid separation device includes a gas-liquid separator 14, a fifth manual shut-off valve 15, a pneumatic shut-off valve 16, a safety valve 17, a gas regenerator 18, a first pressure sensor 20, a second pressure sensor 21, and a third pressure The sensor 22; said also includes a throttling device to prevent water hammer; the gas-liquid separator 14 is connected to the common end of the third regulating valve 13 and the liquid nitrogen mist generating device 19, and the first pressure sensor 20 is connected to the gas At the bottom of the liquid separator 14, the second pressure sensor 21, the third pressure sensor 22, and the fifth manual shut-off valve 15 are respectively connected to the top of the gas-liquid separator 14. The other end of the fifth manual shut-off valve 15 is simultaneously connected to the safety valve. 17. The pneumatic shut-off valve 16 is connected. After the safety valve 17 is connected in parallel with the two ends of the pneumatic shut-off valve 16, it is connected to the gas regenerator 18, and the other end of the gas regenerator 18 is connected to the air.
[0021] figure 1 Schematic diagram of water hammer test for cryogenic pipeline system. On the basis of not changing the original piping system, build a water hammer pressure test system by adding pressure measuring points, adding pressure sensors on the top, inlet and exhaust of the gas-liquid separator, according to the non-throttling device and increasing the section. The two states of the flow device respectively measure the water hammer pressure formed during the exhaust process of the gas-liquid separator.
[0022] figure 2 It is the pressure test curve without throttling device. The pressure of the liquid nitrogen tank is maintained at 1MPa. Without the throttling device installed in the pipeline, the top pressure of the gas-liquid separator and the inlet pressure of the gas-liquid separator both reached 9.9 MPa after the exhaust valve was opened for about 3 seconds, forming a water hammer phenomenon. Under the same working conditions, a total of 10 tests were carried out. In each test, water hammer occurred in the pipeline. The peak water hammer pressure was basically the same, and the pipeline vibrated obviously with loud noise.
[0023] image 3 Pressure test curve for installing throttling device. The pressure of the liquid nitrogen tank is maintained at 1MPa. With the throttling device installed in the pipeline, the top pressure of the gas-liquid separator and the inlet pressure of the gas-liquid separator remain stable during the opening process of the exhaust valve, and there is no sudden change in pressure and no water hammer phenomenon occurs. Under the same working conditions, a total of 10 tests were carried out, and there was no water hammer phenomenon, no major pressure fluctuations, and no vibration in the pipeline.
[0024] Figure 4 Schematic diagram of throttling device. All the throttling devices are made of 304 stainless steel. Firstly, the upper part of the U-shaped throttle tube 27 is 10mm away from the bottom of the circular connecting plate 26 and the lower part of the U-shaped throttle tube 27 is 20mm away from the bottom of the circular cap. 9 small holes with Φ2 equidistantly distributed, and then the U-shaped throttle tube 27 and the circular connecting plate 26 are welded. The bottom of the U-shaped throttle tube 27 adopts a circular tube cap, and the circular tube cap adopts a streamlined structure, which is convenient to reduce the resistance in the liquid flow process. The upper hole is mainly used for air intake, and the lower hole is mainly used for liquid intake. The role of.
[0025] The T-shaped dispersing cap 25 and the circular connecting plate 26 are connected by M12 threads. The height between the T-shaped dispersing cap 25 and the circular connecting plate 26 can be adjusted, and the adjustment range is 0-20mm. The diameter of the T-type diffuser cap 25 is 58mm, and its function is to prevent the liquid from directly impacting the inner cavity of the gas-liquid separator and to ensure the smooth rise of the liquid level. The thickness of the circular connecting plate 26 is 12 mm, and 8 Φ10 holes are opened along the circumferential direction with a diameter of 30 mm to realize the function of air intake and liquid intake.
[0026] The installation method of the throttling device: firstly, weld the groove reserved at the bottom of the circular connecting plate 26 with the pipeline, and then weld the gas-liquid separator through the groove reserved at the top of the circular connecting plate 26.
[0027] The workflow of the entire pipeline is as follows:
[0028] (1) Open the first manual shut-off valve 2, the first regulating valve 3, the second manual shut-off valve 5, and the third manual shut-off valve 6 to pressurize the liquid nitrogen tank. When the pressure of the liquid nitrogen tank 1 meets the requirements for use, Close the first regulating valve 3 to stop the pressurization; when the pressure of the liquid nitrogen tank 1 is greater than the upper limit, open the third manual shut-off valve 6 or the second regulating valve 7 to release the pressure of the liquid nitrogen tank, and the muffler 8 reduces the noise during the pressure release process ;
[0029] (2) Open the fourth manual shut-off valve 9, the emergency shut-off valve 10, and the third regulating valve 13 to deliver liquid nitrogen and provide liquid nitrogen to the liquid nitrogen mist generating device 19;
[0030] (3) During the liquid nitrogen transportation process, open the gas-liquid separator 14 to remove the nitrogen in the pipeline in time, and perform real-time monitoring of the pressure during the nitrogen discharge process;
[0031] The content not described in detail in the present invention is well-known to those skilled in the art.
