Suck-back prevention device

Abstract

The utility model provides a suck-back prevention device which comprises a gas storage tank, a buffer tank, a reaction tank and a waste gas absorption device, a reaction solvent is arranged in the reaction tank, an inlet end of the buffer tank is connected with the gas storage tank through a ventilation pipeline, an outlet end of the buffer tank is inserted into the reaction solvent in the reaction tank through a gas outlet pipeline, and the waste gas absorption device is arranged in the reaction tank. The outlet end is higher than the liquid level of the reaction solvent, and the waste gas absorption device is connected with the reaction tank. When ventilation is too slow or is stopped, suck-back can be prevented through the buffer tank, and due to the fact that the outlet end is higher than the liquid level of the reaction solvent, even if a little suck-back phenomenon occurs, the reaction solvent cannot be lost due to siphonage. The suck-back liquid can automatically flow back to the reaction tank, the reaction solvent is not wasted and polluted, the suck-back liquid in the buffer tank does not need to be treated by additional means such as nitrogen blowing, and the operation is greatly simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical pharmaceutical production, in particular to an anti-backflow device. Background Art

[0002] Aeration and absorption operations are common in the chemical and pharmaceutical fields, widely used for the dosing of gases or low-boiling-point liquids such as hydrogen chloride, chlorine, sulfur dioxide, carbon dioxide, ethyl nitrite, and methyl nitrite, as well as the preparation of solutions of certain concentrations. These gases all have high solubility in the absorption solvent, but it is difficult for the aeration rate during dosing to be perfectly aligned with the absorption and dissolution rate. In particular, if aeration is too slow or stopped, the absorption and dissolution rate will exceed the aeration rate, resulting in negative pressure in the aeration line. Solvents in the reaction tank can be sucked back into the aeration line or even back into the gas storage tank, causing accidents.

[0003] In order to prevent accidents caused by backflow, it is necessary to install a buffer tank on the ventilation pipeline to prevent backflow. In the prior art, a parallel tank design is usually adopted for buffering and preventing backflow. The bottom of the buffer tank is lower than the liquid level of the reaction tank, forming a negative pressure in the ventilation pipeline, which easily forms a siphon phenomenon. The solvent in the reaction tank will be backflowed into the buffer tank, causing the solvent in the reaction tank to decrease. Alternatively, there is also a method of connecting nitrogen to the ventilation pipeline in the prior art. When the ventilation is stopped, the residual gas to be introduced is flushed with nitrogen so that the gas is fully absorbed. However, when using the nitrogen method, if the operation is wrong, or the nitrogen source is short of nitrogen and there is no nitrogen flushing, a large amount of reaction liquid will be backflowed into the buffer tank, causing production losses. If the buffer tank is not polluted, the backflow reaction liquid can be reused, but it also increases the operation of withdrawing the solvent from the buffer tank. Utility Model Content

[0004] In view of this, the utility model aims to propose an anti-backflow device to solve the problem that when ventilation is too slow or ventilation is stopped, the backflow liquid sucked into the buffer tank is difficult to handle and will cause certain losses.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0006] A backflow prevention device includes a gas storage tank, a buffer tank, a reaction tank and a waste gas absorption device. A reaction solvent is arranged inside the reaction tank. The inlet end of the buffer tank is connected to the gas storage tank through a ventilation line. The outlet end of the buffer tank is inserted into the reaction solvent inside the reaction tank through an air outlet line. The height of the outlet end is higher than the liquid level of the reaction solvent. The waste gas absorption device is connected to the reaction tank. When ventilation is too slow or ventilation is stopped, backflow can be prevented by utilizing the presence of the buffer tank. Since the height of the outlet end is higher than the liquid level of the reaction solvent, even if there is a slight backflow, the reaction solvent will not be lost due to siphoning. The backflow liquid can automatically flow back to the reaction tank without wasting or contaminating the reaction solvent. There is no need to handle the backflow liquid in the buffer tank through additional means such as blowing nitrogen.

[0007] Furthermore, the anti-backflow device includes a vent valve, a purge valve, and a valve switch. The vent valve and purge valve are both connected to the valve switch and configured so that the purge valve is closed when the vent valve is open and open when the vent valve is closed. The vent valve and purge valve are disposed on the ventilation pipeline. Because the vent valve and purge valve are integrated into the same valve switch, the purge valve can be operated simultaneously with the vent valve by using the valve switch, avoiding forgetting to operate the purge valve when opening and closing the vent valve.

[0008] Furthermore, the vent valve and the air release valve are three-way valves, each including a first interface, a second interface, and a third interface. The first interface is connected to the gas storage tank, the second interface is connected to the buffer tank via a vent line, and the third interface is connected to the external environment. Different states of the three-way valve are adjusted according to the reaction process.

[0009] Furthermore, the vent valve is electrically connected to the valve switch, and the deflation valve is electrically connected to the valve switch, so that the vent valve and the deflation valve can be operated simultaneously through the valve switch.

[0010] Furthermore, the outlet end is the lowest point of the buffer tank, and the outlet end is conical or spherical, which facilitates the backflow of the suction liquid from the buffer tank back to the reaction tank without dead ends, avoiding the liquid remaining inside the buffer tank and causing waste of reaction solvent.

[0011] Furthermore, the air outlet pipeline includes a first vertical section, an inclined section, and a second vertical section, wherein the inclined section is arranged to be inclined downward in a top-down direction, one end of the first vertical section is connected to the outlet end, the other end of the first vertical section is connected to one end of the inclined section, one end of the second vertical section is inserted into the reaction solvent of the reaction tank, and the other end of the second vertical section is connected to the other end of the inclined section. The air outlet pipeline is arranged into three parts to facilitate the connection between the buffer tank and the reaction tank. The arrangement of the inclined section can ensure that the backflow liquid retained in the buffer tank flows directly into the reaction tank without retention, avoiding residue in the air outlet pipeline.

[0012] Furthermore, the buffer tank is made of transparent material, which makes it easy to observe the situation inside the buffer tank.

[0013] Furthermore, the gas storage tank is provided with a main valve for controlling the opening or closing of the gas storage tank, and the reaction tank is provided with a stirrer for accelerating the reaction between the gas in the reaction tank and the reaction solvent by stirring.

[0014] Compared with the prior art, the anti-backflow device described in the utility model has the following advantages:

[0015] (1) When ventilation is too slow or stops, the presence of a buffer tank can prevent backflow. Since the height of the outlet end is higher than the liquid level of the reaction solvent, even if there is a slight backflow, the reaction solvent will not be lost due to siphoning.

[0016] (2) Since the vent valve and the purge valve are integrated into the same valve switch, the purge valve can be operated simultaneously with the vent valve by using the valve switch, thus avoiding forgetting to operate the purge valve when opening and closing the vent valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 This is a schematic diagram of an anti-backflow device described in an embodiment of the present utility model.

[0019] Description of reference numerals:

[0020] 1. Gas storage tank; 2. Buffer tank; 21. Inlet end; 22. Outlet end; 3. Reactor; 4. Waste gas absorption device; 5. Ventilation pipe; 6. Exhaust pipe; 61. First vertical section; 62. Inclined section; 63. Second vertical section; 7. Three-way valve; 8. Main valve; 9. Agitator; 10. Waste gas pipe. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. The embodiments described in the present invention are exemplary and intended to be used to explain the present invention, and should not be understood as limiting the present invention.

[0022] It should be noted that the terms "upper," "lower," "left," "right," "front," and "rear" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The embodiments of the present invention and the features therein may be combined unless otherwise specified.

[0023] like Figure 1 As shown, the utility model proposes an anti-backflow device, including a gas storage tank 1, a buffer tank 2, a reaction tank 3 and a waste gas absorption device 4. The gas storage tank 1 is a gas source, and a reaction solvent is arranged inside the reaction tank 3. The inlet end 21 of the buffer tank 2 is connected to the gas storage tank 1 through a ventilation pipe 5, and the outlet end 22 of the buffer tank 2 is inserted into the reaction solvent inside the reaction tank 3 through an air outlet pipe 6. The height of the outlet end 22 is higher than the liquid level of the reaction solvent. The waste gas absorption device 4 is connected to the reaction tank 3. The gas from the gas storage tank 1 passes through the ventilation pipe 5, the buffer tank 2 and the air outlet pipe 6 in sequence to reach the reaction tank 3, and reacts with the reaction solvent inside the reaction tank 3. When the ventilation is too slow or the ventilation stops, the presence of the buffer tank 2 can prevent backflow. Since the height of the outlet end 22 is higher than the liquid level of the reaction solvent, even if there is a slight backflow, the reaction solvent will not be lost due to the siphon phenomenon. The backflow liquid can automatically flow back to the reaction tank 3, without wasting or contaminating the reaction solvent, and without the need for additional means such as nitrogen blowing to treat the backflow liquid in the buffer tank, greatly simplifying the operation. The buffer tank 2 can be supported by a bracket to ensure that the height of the outlet end 22 is higher than the liquid level of the reaction solvent.

[0024] The waste gas absorption device 4 is connected to the reaction tank 3 through the waste gas pipeline 10, and the waste gas pipeline 10 is far away from the reaction solvent inside the reaction tank 3, so as to avoid the reaction solvent flowing into the waste gas absorption device 4 through the waste gas pipeline 10 and causing waste.

[0025] As a preferred embodiment of the present invention, the anti-backflow device includes a vent valve, a purge valve and a valve switch. The vent valve and the purge valve are both connected to the valve switch and are configured so that the purge valve is closed when the vent valve is open and is opened when the vent valve is closed. The vent valve and the purge valve are arranged on the ventilation pipe 5. The vent valve is opened to allow the gas in the gas storage tank 1 to circulate in the anti-backflow device, and the purge valve is opened to discharge the gas in the anti-backflow device or allow air in the external environment to enter the anti-backflow device, so that the air pressure inside and outside the anti-backflow device is balanced. Since the vent valve and the purge valve are integrated on the same valve switch, the purge valve can be operated while the vent valve is operated by the valve switch, avoiding forgetting to operate the purge valve when opening and closing the vent valve. For example, the purge valve is opened synchronously when the vent valve is closed, and the two operations are completed at one time, avoiding the situation where only the vent valve is closed but the purge valve is forgotten to be opened, causing backflow. The vent valve is opened and the bleed valve is closed simultaneously, and the two operations are completed at one time, avoiding the situation where only the vent valve is opened but the bleed valve is forgotten to be closed, causing gas leakage.

[0026] Regarding the vent valve and the air release valve, the vent valve is electrically connected to the valve switch, and the air release valve is electrically connected to the valve switch, so that the vent valve and the air release valve can be operated simultaneously through the valve switch. Alternatively, the vent valve and the air release valve are three-way valves 7, which include a first interface, a second interface, and a third interface. The first interface is connected to the gas tank 1, the second interface is connected to the buffer tank 2 via the ventilation line 5, and the third interface is connected to the external environment. When the three-way valve 7 is in a first state, the gas tank 1 is connected to the ventilation line 5 via the three-way valve 7, and the external environment and the ventilation line 5 are cut off. When the three-way valve 7 is in a second state, the external environment is connected to the ventilation line 5 via the three-way valve 7, and the gas tank 1 and the ventilation line 5 are cut off. When the three-way valve 7 is in a third state, the gas tank 1 is partially connected to the ventilation line 5 via the three-way valve 7, and the corresponding valve opening is smaller than that in the first state. The external environment is partially connected to the ventilation line 5 via the three-way valve 7, and the corresponding valve opening is smaller than that in the second state. Preferably, the vent valve and the air release valve are in the form of a three-way valve 7.

[0027] For the buffer tank 2, the outlet end 22 is the lowest point of the buffer tank 2 and is conical or spherical, so as to facilitate the backflow of the sucked liquid from the buffer tank 2 back to the reaction tank 3 without dead ends, thereby avoiding the residual reaction solvent in the buffer tank 2 and causing waste.

[0028] As for the gas outlet pipeline 6, the gas outlet pipeline 6 includes a first vertical section 61, an inclined section 62 and a second vertical section 63. The inclined section 62 is arranged downwardly in an inclined direction from top to bottom. One end of the first vertical section 61 is connected to the outlet end 22, the other end of the first vertical section 61 is connected to one end of the inclined section 62, one end of the second vertical section 63 is inserted into the reaction solvent of the reaction tank 3, and the other end of the second vertical section 63 is connected to the other end of the inclined section 62. The gas outlet pipeline 6 is arranged into three parts to facilitate the connection between the buffer tank 2 and the reaction tank 3. The provision of the inclined section 62 can ensure that the backflow liquid retained in the buffer tank 2 flows directly into the reaction tank 3 without retention, avoiding residue in the gas outlet pipeline 6.

[0029] As a preferred embodiment of the present invention, the buffer tank 2 is made of a transparent material, such as glass, to facilitate observation of the situation in the buffer tank 2. Furthermore, a strip scale line is provided on the outside of the buffer tank 2 to facilitate observation of the volume of the sucked liquid in the buffer tank 2.

[0030] In order to ensure that ventilation reaches the reaction tank 3 smoothly, the volume of the buffer tank 2 is 2-10 times the volume of the ventilation pipeline 5. Furthermore, the volume of the buffer tank 2 is 2-5 L. The volume of the buffer tank 2 does not need to be too large.

[0031] The gas storage tank 1 is provided with a main valve 8 for controlling the opening or closing of the gas storage tank 1. The reaction tank 3 is provided with a stirrer 9 for stirring and accelerating the reaction between the gas in the reaction tank 3 and the reaction solvent.

[0032] When the anti-backflow device of the present invention is in use, a reaction solvent is added to the reaction tank 3, and the agitator 9 is turned on at room temperature or under cooling conditions. The main valve 8 is opened, the air intake speed is adjusted, and the three-way valve 7 is set to the first state. The gas in the gas storage tank 1 passes through the three-way valve 7, the ventilation pipe 5, the buffer tank 2, and the outlet pipe 6 to reach the bottom of the reaction tank 3. With the help of the stirring action of the agitator 9, the reaction solvent fully absorbs the gas. When the gas is introduced through the gas storage tank 1, the basic balance between ventilation and absorption is maintained. The judgment standard for the basic balance between ventilation and absorption is: there is no large bubble escaping and no obvious backflow. When the reaction is carried out in the reaction tank 3, the waste gas generated is discharged through the waste gas pipe 10 and collected in the waste gas absorption device 4.

[0033] After the ventilation is completed, close the main valve 8 first, adjust the three-way valve 7 to the second state, and the ventilation is completed. No toxic gas will be released during this process because the negative pressure in the pipe only allows air from the external environment to enter, balance the internal and external pressures, and prevent the liquid in the reaction tank 3 from being sucked back into the buffer tank 2.

[0034] If ventilation is stopped or the ventilation speed is slowed down during the process, the three-way valve 7 is adjusted to the third state to allow a small amount of external ambient air to enter the anti-backflow device to balance the negative pressure of the anti-backflow device and ensure that the ventilation process proceeds smoothly.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An anti-backflow device, comprising a gas storage tank (1), a buffer tank (2), a reaction tank (3) and an exhaust gas absorption device (4), wherein a reaction solvent is arranged inside the reaction tank (3), characterized in that: The inlet end (21) of the buffer tank (2) is connected to the gas storage tank (1) via a ventilation pipeline (5); the outlet end (22) of the buffer tank (2) is inserted into the reaction solvent inside the reaction tank (3) via an outlet pipeline (6); the height of the outlet end (22) is higher than the liquid level of the reaction solvent; and the waste gas absorption device (4) is connected to the reaction tank (3).

2. The anti-backflow device according to claim 1, characterized in that: The anti-backflow device comprises a vent valve, an air release valve and a valve switch. The vent valve and the air release valve are both connected to the valve switch and are configured so that the air release valve is closed when the vent valve is open and the air release valve is opened when the vent valve is closed. The vent valve and the air release valve are arranged on the vent pipe (5).

3. The anti-backflow device according to claim 2, characterized in that: The vent valve and the air release valve are three-way valves (7), and the three-way valve (7) comprises a first interface, a second interface, and a third interface, wherein the first interface is connected to the gas storage tank (1), the second interface is connected to the buffer tank (2) via a vent pipe (5), and the third interface is connected to the external environment.

4. The anti-backflow device according to claim 2, characterized in that: The vent valve is electrically connected to the valve switch, and the air release valve is electrically connected to the valve switch.

5. The anti-backflow device according to claim 1, characterized in that: The outlet end (22) is the lowest point of the buffer tank (2), and the outlet end (22) is conical or spherical.

6. The anti-backflow device according to claim 1, characterized in that: The gas outlet pipeline (6) comprises a first vertical section (61), an inclined section (62) and a second vertical section (63), wherein the inclined section (62) is arranged to be inclined downward in a top-down direction, one end of the first vertical section (61) is connected to the outlet end (22), the other end of the first vertical section (61) is connected to one end of the inclined section (62), one end of the second vertical section (63) is inserted into the reaction solvent of the reaction tank (3), and the other end of the second vertical section (63) is connected to the other end of the inclined section (62).

7. The anti-backflow device according to claim 1, characterized in that: The buffer tank (2) is made of transparent material.

8. The anti-backflow device according to claim 1, characterized in that: The gas storage tank (1) is provided with a main valve (8) for controlling the opening or closing of the gas storage tank (1), and the reaction tank (3) is provided with a stirrer (9).

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