A liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control

Abstract

The utility model discloses a kind of liquid nitrogen storage tank pressure relief protection devices based on liquid column differential pressure control, belong to pressure vessel testing equipment field. Including liquid tank, air inlet and exhaust pipe and connecting pipe. Middle in liquid tank is provided with baffle, the baffle will the internal space of the liquid tank be divided into gas chamber and liquid chamber, liquid level control hole is opened on the side wall of the baffle far from the liquid chamber, the liquid level control hole of uppermost layer is located below the top edge of the baffle;The air inlet and exhaust pipe is vertically inserted in the top of the liquid tank, and the bottom end of the air inlet and exhaust pipe extends to below in the liquid chamber, the bottom end face of the air inlet and exhaust pipe is located below the liquid level control hole;The connecting pipe is vertically inserted in the bottom of the liquid tank, and the top end of the connecting pipe extends to in the gas chamber. The utility model is discharged by liquid column static pressure difference The pressure relief device of two-way protection of overpressure / negative pressure, especially applicable to the pressure test working condition of liquid nitrogen storage tank.

Description

Technical Field

[0001] This utility model relates to the technical field of pressure vessel testing equipment, specifically to a pressure relief protection device for liquid nitrogen storage tanks based on liquid column differential pressure control. Background Technology

[0002] Before using a liquid nitrogen storage tank, a positive and negative pressure test is a crucial step in verifying the structural integrity of the tank. Traditional methods use safety valves or rupture discs. However, existing technologies have significant drawbacks:

[0003] Small pressure valves are difficult to procure: the test pressure is usually below 10 kPa, while the minimum opening pressure of commercially available safety valves is mostly above 35 kPa.

[0004] High cost: Customized miniature safety valves cost 3-5 times more than conventional valves, and have a long delivery cycle;

[0005] Insufficient precision: Mechanical safety valves have an operating error of ±15%, which can easily lead to overpressure deformation or negative pressure collapse of the storage tank;

[0006] Poor reusability: Rupture discs are disposable consumables, and repeated tests require frequent replacement. Utility Model Content

[0007] This invention provides a pressure relief protection device for liquid nitrogen storage tanks based on differential pressure control of liquid column, which can solve one of the problems of high cost, insufficient accuracy and poor reusability in the existing technology of using safety valves or rupture discs for positive and negative pressure tests.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] A pressure relief protection device for a liquid nitrogen storage tank based on differential pressure control of a liquid column, comprising:

[0010] A liquid tank has a partition in the middle inside the liquid tank. There is a gap between the top edge of the partition and the top wall of the liquid tank. The bottom edge and side edge of the partition are fixedly sealed to the inner wall of the liquid tank. The partition divides the internal space of the liquid tank into a gas chamber and a liquid chamber. A liquid level control hole is opened on the side wall of the liquid chamber away from the partition. The uppermost liquid level control hole is located below the top edge of the partition.

[0011] An air inlet and outlet pipe is vertically inserted into the top of the liquid tank, and the bottom end of the air inlet and outlet pipe extends to the lower part of the liquid chamber, with the bottom end face of the air inlet and outlet pipe located below the liquid level control hole.

[0012] A connecting pipe is inserted vertically into the bottom of the liquid tank, and the top end of the connecting pipe extends into the gas chamber.

[0013] As a further embodiment of this utility model: the top end face of the connecting pipe is aligned with the top edge of the partition.

[0014] As a further embodiment of this utility model: a flange is fixedly connected to the bottom end of the connecting pipe, and a rubber gasket is provided on the sealing surface of the flange.

[0015] As a further embodiment of this utility model, a bubble level is also fixedly installed on the top of the liquid tank.

[0016] As a further embodiment of this invention: at least two liquid level control holes are provided on the side wall of the liquid chamber, and the holes are equipped with swing-open sealing plugs.

[0017] As a further embodiment of this utility model: the diameters of the intake and exhaust pipes and the connecting pipes are equal, and a filter layer is provided inside both the intake and exhaust pipes and the connecting pipes.

[0018] As a further embodiment of this invention: the length of the inlet and outlet pipe located in the liquid chamber is equal to the length of the connecting pipe located in the gas chamber.

[0019] As a further embodiment of this utility model: the distance between the top end of the connecting pipe and the top wall of the liquid tank is equal to the distance between the bottom end of the inlet and outlet pipe and the bottom wall of the liquid tank.

[0020] As a further embodiment of this utility model, the height of the liquid tank is 400mm.

[0021] As a further embodiment of this utility model: the distance between the top end of the connecting pipe and the top wall of the liquid tank and the distance between the bottom end of the inlet and outlet pipe and the bottom wall of the liquid tank are both 100mm.

[0022] The beneficial effects of this utility model are:

[0023] This utility model provides a liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control, including a liquid tank, an inlet and outlet pipe, and a connecting pipe. The liquid tank is divided into a gas chamber and a liquid chamber of equal volume by a partition. The inlet and outlet pipe is vertically inserted into the top of the liquid tank and extends to the bottom of the liquid chamber. The connecting pipe is vertically inserted into the bottom of the liquid tank and extends to the gas chamber. The set pressure relief value is determined by the height difference between the bottom end face of the inlet and outlet pipe and the top end face of the connecting pipe. The pressure relief point is accurately set by the liquid column height with an error of ≤±0.005MPa, which is far superior to mechanical valves. This device simultaneously solves the problems of positive pressure relief and negative pressure gas replenishment, achieving bidirectional protection. The device is made of ordinary steel, eliminating the need to purchase special safety valves, resulting in low cost. It can be reused repeatedly, and can adapt to different pressure tests by changing the liquid or adjusting the height of the inlet and outlet pipe and the connecting pipe. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 This is a front sectional view of the overall structure of this utility model;

[0026] Figure 2 yes Figure 1 Enlarged schematic diagram of the structure at point A in the middle;

[0027] Figure 3 This is a top view of the overall structure of this utility model;

[0028] Figure 4 This is a top view sectional diagram of the overall structure of this utility model.

[0029] In the diagram: 1. Liquid tank; 101. Gas chamber; 102. Liquid chamber; 2. Baffle; 3. Liquid level control hole; 4. Inlet and outlet pipes; 5. Connecting pipe; 6. Flange; 601. Rubber gasket; 7. Filter layer; 8. Bubble level. Detailed Implementation

[0030] The technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0031] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on this utility model.

[0032] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0033] Please see Figure 1-4 As shown, this utility model embodiment provides a liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control, including a liquid tank 1, an inlet and outlet pipe 4, and a connecting pipe 5.

[0034] Please refer to Figure 1 As shown, the liquid tank 1 is a rectangular structure made of stainless steel, with dimensions of 300mm in length, 150mm in width, and 400mm in height. A partition 2 is installed in the middle of the liquid tank 1, with a 100mm gap between the top edge of the partition 2 and the top wall of the liquid tank 1. The bottom and sides of the partition 2 are fixedly sealed to the inner wall of the liquid tank 1. The partition 2 divides the internal space of the liquid tank 1 into a gas chamber 101 and a liquid chamber 102 of the same volume.

[0035] Please see Figure 3 As shown, a bubble level 8 is also fixedly installed on the top of the liquid tank 1 to calibrate the levelness of the liquid tank 1 after installation.

[0036] Please see Figure 2 As shown, a liquid level control hole 3 is provided on the side wall of the liquid chamber 102 away from the partition 2, with the uppermost liquid level control hole 3 located below the top edge of the partition 2. The diameter of the liquid level control hole 3 is Φ8mm. At least two liquid level control holes 3 are provided on the side wall of the liquid chamber 102, and the orifice is equipped with a swing-open sealing plug (not shown in the figure). When filling with water, loosen the sealing plug, wait for water to continuously flow from the liquid level control hole 3 for 2 seconds, and then tighten the sealing plugs one by one to ensure that the liquid level in the liquid tank 1 is flush with the lower edge of the liquid level control hole 3.

[0037] Please see Figure 1 As shown, the inlet and outlet pipe 4 is vertically inserted into the top of the liquid tank 1, and the bottom end of the inlet and outlet pipe 4 extends into the lower part of the liquid chamber 102. The portion of the inlet and outlet pipe 4 inside the liquid chamber 102 does not contact the inner wall of the liquid tank 1 or the partition 2. The bottom end face of the inlet and outlet pipe 4 is located below the liquid level control hole 3. Liquid can be injected into the liquid tank 1 through the inlet and outlet pipe 4, and gas inside the tank can also be discharged through the inlet and outlet pipe 4. The distance between the bottom end face of the inlet and outlet pipe 4 and the bottom wall of the liquid tank 1 is 100mm.

[0038] Please see Figure 1 As shown, the connecting pipe 5 is vertically inserted into the bottom of the liquid tank 1, and the top end of the connecting pipe 5 extends into the gas chamber 101. The portion of the connecting pipe 5 inside the gas chamber 101 does not contact the inner wall of the liquid tank 1 or the partition 2. The top end face of the connecting pipe 5 is aligned with the top edge of the partition 2, and the distance between the top end face of the connecting pipe 5 and the top wall of the liquid tank 1 is 100mm. The height difference H between the bottom end face of the inlet / outlet pipe 4 and the top end face of the connecting pipe 5 satisfies: H = P / ρg, where P is the set pressure relief value, ρ is the liquid density, and g is the acceleration due to gravity. A flange 6 is also fixedly connected to the bottom end of the connecting pipe 5. The sealing surface of the flange 6 is equipped with a rubber gasket 601. The entire pressure relief protection device is fixedly installed on the liquid nitrogen storage tank through the flange 6, and the connecting pipe 5 communicates with the inside of the liquid nitrogen storage tank.

[0039] Furthermore, the length of the inlet / outlet pipe 4 within the liquid chamber 102 is equal to the length of the connecting pipe 5 within the gas chamber 101. The diameters of the inlet / outlet pipe 4 and the connecting pipe 5 are equal, and both the inlet / outlet pipe 4 and the connecting pipe 5 are provided with a filter layer 7, which filters impurities in the gas and liquid.

[0040] The working principle of this utility model:

[0041] When the liquid nitrogen storage tank equipment needs to be tested for positive and negative pressure, first install this utility model on the liquid nitrogen storage tank equipment to be tested through flange 6, and check the level of the liquid tank 1 after installation by observing the bubble level 8.

[0042] Slowly add liquid (water) into the liquid chamber 102 inside the liquid tank 1 through the inlet and outlet pipes 4. As the water level rises, excess water is discharged from the liquid level control hole 3. After standing for a period of time, when no more water is discharged from the liquid tank 1, seal all the liquid level control holes 3 with sealing plugs, and the device can work normally.

[0043] During positive pressure testing: Once the pressure of the liquid nitrogen storage tank exceeds the rated pressure, the device starts to work. The gas in the liquid nitrogen storage tank enters the gas chamber 101 inside the liquid tank 1 through the connecting pipe 5. At this time, the liquid level in the liquid chamber 102 is under pressure, which squeezes the excess liquid into the inlet and outlet pipe 4. When the liquid level in the liquid chamber 102 is lower than the lower opening of the inlet and outlet pipe 4, the excess pressure is released from the inlet and outlet pipe 4.

[0044] During the negative pressure test: After the negative pressure inside the liquid nitrogen storage tank exceeds the set pressure, the device will start to work. The liquid level in the inlet and outlet pipe 4 will drop due to the external air pressure. After the liquid level drops to the critical point at the bottom of the inlet and outlet pipe 4, the air will pass through the inlet and outlet pipe 4 into the liquid tank 1. The air in the liquid tank 1 will then enter the liquid nitrogen storage tank through the connecting pipe 5.

[0045] The preferred embodiments of this utility model have been described in detail above and should not be considered as limiting the scope of this utility model. All equivalent changes and improvements made within the scope of the claims of this utility model should still fall within the patent coverage of this utility model.

Claims

1. A pressure relief protection device for a liquid nitrogen storage tank based on differential pressure control of a liquid column, characterized in that, include: A liquid tank (1) is provided with a partition (2) in the middle of the liquid tank (1). There is a gap between the top edge of the partition (2) and the top wall of the liquid tank (1). The bottom edge and side edge of the partition (2) are fixedly sealed to the inner wall of the liquid tank (1). The partition (2) divides the internal space of the liquid tank (1) into a gas chamber (101) and a liquid chamber (102). A liquid level control hole (3) is provided on the side wall of the liquid chamber (102) away from the partition (2). The uppermost liquid level control hole (3) is located below the top edge of the partition (2). An air inlet and outlet pipe (4) is vertically inserted into the top of the liquid tank (1), and the bottom end of the air inlet and outlet pipe (4) extends to the bottom of the liquid chamber (102). The bottom end face of the air inlet and outlet pipe (4) is located below the liquid level control hole (3). A connecting pipe (5) is vertically inserted into the bottom of the liquid tank (1), and the top end of the connecting pipe (5) extends into the gas chamber (101).

2. The liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 1, characterized in that: The top end face of the connecting pipe (5) is aligned with the top edge of the partition (2).

3. The liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 2, characterized in that: The bottom end of the connecting pipe (5) is fixedly connected to a flange (6), and the sealing surface of the flange (6) is provided with a rubber gasket (601).

4. The liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 1, characterized in that: A bubble level (8) is also fixedly installed on the top of the liquid tank (1).

5. The liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 1, characterized in that: At least two liquid level control holes (3) are provided on the side wall of the liquid chamber (102), and the holes are equipped with swing-open sealing plugs.

6. The liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 1, characterized in that: The diameters of the intake and exhaust pipes (4) and the connecting pipe (5) are equal, and both the intake and exhaust pipes (4) and the connecting pipe (5) are provided with a filter layer (7).

7. A liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 6, characterized in that: The length of the inlet and outlet pipe (4) located in the liquid chamber (102) is equal to the length of the connecting pipe (5) located in the gas chamber (101).

8. The liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 7, characterized in that: The distance between the top end of the connecting pipe (5) and the top wall of the liquid tank (1) is equal to the distance between the bottom end of the inlet and outlet pipe (4) and the bottom wall of the liquid tank (1).

9. A liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 8, characterized in that: The height of the liquid tank (1) is 400mm.

10. A liquid nitrogen storage tank pressure relief protection device based on liquid column differential pressure control according to claim 9, characterized in that: The distance between the top end of the connecting pipe (5) and the top wall of the liquid tank (1) and the distance between the bottom end of the inlet and outlet pipe (4) and the bottom wall of the liquid tank (1) are both 100mm.

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