Formic acid injection system and vacuum furnace

Abstract

The utility model relates to the technical field of vacuum furnaces. A formic acid injection system comprises a formic acid tank, a second conveying pipe, a mixing tank, a storage tank, a gas injection assembly, a first switch valve, a third switch valve and a third conveying pipe, the inlet end of the second conveying pipe is arranged at the bottom of the formic acid tank, the outlet end of the second conveying pipe is arranged at the bottom of the mixing tank, the inlet end of the third conveying pipe is arranged at the top of the mixing tank, and the outlet end of the third conveying pipe is arranged at the top of the storage tank; the third switch valve is arranged on the top of the mixing tank, the upper portion of the gas injection assembly is connected with the third switch valve, the lower portion of the gas injection assembly is arranged at the bottom of the mixing tank, and the first switch valve is arranged on the third conveying pipe. And the process environment in the furnace is prevented from being influenced by the dramatic change of the temperature of the mixed gas.

Description

Technical Field

[0001] The utility model relates to the technical field of vacuum furnaces, in particular to a formic acid injection system and a vacuum furnace. Background Art

[0002] Formic acid, commonly known as formic acid, is a colorless, volatile liquid with a pungent odor. It is a weak electrolyte with a melting point of 8.6°C and a boiling point of 100.8°C. It is highly acidic and corrosive, causing skin blistering. It is an organic chemical raw material. Formic acid is a strong reducing agent. At high temperatures, formic acid gas itself can consume oxygen through a chemical reaction, resulting in oxygen-free welding. It can also reduce oxidized metal surfaces through a reduction reaction, leaving them clean. Therefore, in the semiconductor and other welding and packaging fields, the use of formic acid as a cleaning agent or reducing agent is increasing in equipment.

[0003] The existing vacuum furnace does not have a storage tank to store the mixed gas of gaseous formic acid and nitrogen and maintain a constant temperature. After the mixed gas is filled into the vacuum furnace, the process environment in the furnace will be affected by the sudden change in the temperature of the mixed gas. Summary of the Invention

[0004] The utility model provides a formic acid injection system, which is used to solve the problem in the prior art that the rapid change of the temperature of the mixed gas affects the process environment in the furnace.

[0005] A formic acid injection system includes a formic acid tank, a second delivery pipe, a mixing tank, a storage tank, a gas injection assembly, a first on-off valve, a third on-off valve, and a third delivery pipe; the inlet end of the second delivery pipe is arranged at the bottom of the formic acid tank, the outlet end of the second delivery pipe is arranged at the bottom of the mixing tank, the inlet end of the third delivery pipe is arranged at the top of the mixing tank, the outlet end of the third delivery pipe is arranged at the top of the storage tank, the third on-off valve is arranged at the top of the mixing tank, the upper portion of the gas injection assembly is connected to the third on-off valve, the lower portion of the gas injection assembly is arranged at the bottom of the mixing tank, and the first on-off valve is arranged on the third delivery pipe.

[0006] According to the formic acid injection system of the present invention, it further includes a second switch valve. The second delivery pipe is provided with the second switch valve. The formic acid level in the formic acid tank is greater than the formic acid level in the mixing tank.

[0007] According to the formic acid injection system of the present invention, the storage tank includes a storage tank body, a temperature sensor, a ceramic heater, a heating layer and an insulation layer; the temperature sensor is arranged inside the storage tank body, the heating layer is arranged on the outer layer of the storage tank body, the insulation layer is arranged on the outer layer of the heating layer, and the ceramic heater heats the heating layer.

[0008] According to the formic acid injection system of the present invention, it also includes a second pressure sensor, a second safety pressure relief valve, a storage tank inlet pipe and a storage tank outlet pipe; the second pressure sensor, the second safety pressure relief valve, the storage tank inlet pipe and the storage tank outlet pipe are arranged on the top of the storage tank body, and the outlet end of the third delivery pipe is connected to the storage tank inlet pipe.

[0009] According to the formic acid injection system of the present invention, the formic acid tank includes a first low liquid level sensor, a first high liquid level sensor and a formic acid inlet pipe; the first low liquid level sensor is arranged at the lower part of the formic acid tank, the first high liquid level sensor is arranged at the upper part of the formic acid tank, and the formic acid inlet pipe is arranged at the top of the formic acid tank.

[0010] According to the formic acid injection system of the present invention, the mixing tank includes a second low liquid level sensor, a first safety pressure relief valve, a first pressure sensor and a second high liquid level sensor. The second low liquid level sensor is arranged at the bottom side of the mixing tank, the second high liquid level sensor is arranged in the middle of the mixing tank, the first pressure sensor is arranged at the top of the mixing tank, and the first safety pressure relief valve is arranged at the top of the mixing tank.

[0011] According to the formic acid injection system of the present invention, the gas injection assembly includes a one-way valve, a connecting pipe and a circular pipe; the one-way valve is connected to the connecting pipe and the circular pipe in sequence, the circular pipe is arranged at the inner bottom of the mixing tank, and the circular pipe is provided with multiple through holes.

[0012] According to the formic acid injection system of the present invention, it further includes a flow meter, and the flow meter is provided on the first delivery pipe.

[0013] According to the formic acid injection system of the present invention, it also includes a nitrogen tank and a nitrogen inlet pipe. The nitrogen inlet pipe is arranged on the top of the nitrogen tank, and the inlet end of the first delivery pipe is connected to the nitrogen tank.

[0014] A vacuum furnace comprises the formic acid injection system mentioned above.

[0015] This storage tank stores a mixture of gaseous formic acid and nitrogen at a constant temperature. After charging into a vacuum furnace, sudden temperature fluctuations in the mixed gas prevent the process environment within the furnace from being affected. By pre-mixing the gaseous formic acid and nitrogen in the storage tank, the ratio between the two gases can be precisely controlled, maintaining a constant formic acid concentration and improving the quality of vacuum furnace production. A flow meter maintains a constant pressure in the mixing tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the main structure of the formic acid injection system;

[0018] Figure 2 It is a schematic diagram of the three-dimensional structure of the formic acid injection system;

[0019] Figure 3 It is a schematic diagram of the three-dimensional structure of the storage tank;

[0020] Figure 4 It is a cross-sectional structural diagram of a storage tank;

[0021] Figure numerals: 1. nitrogen tank; 2. formic acid tank; 3. mixing tank; 4. storage tank; 5. flow meter; 6. first switch valve; 7. second switch valve; 8. first delivery pipe; 9. second delivery pipe; 10. third delivery pipe; 11. nitrogen inlet pipe; 21. first low liquid level sensor; 22. first high liquid level sensor; 23. formic acid inlet pipe; 31. third switch valve; 32. second low liquid level sensor; 33. second high liquid level sensor; 34. first safety pressure relief valve; 35. first pressure sensor; 41. second pressure sensor; 42. second safety pressure relief valve; 43. storage tank inlet pipe; 44. storage tank outlet pipe; 45. temperature sensor; 46. ceramic heater; 47. heating layer; 48. insulation layer. DETAILED DESCRIPTION

[0022] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0024] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0025] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0027] The following combination Figure 1-4 A formic acid injection system according to an embodiment of the present invention is described, comprising a formic acid tank 2, a second delivery pipe 9, a mixing tank 3, a storage tank 4, a gas injection assembly, a first on-off valve 6, a third on-off valve 31, and a third delivery pipe 10. The inlet end of the second delivery pipe 9 is disposed at the bottom of the formic acid tank 2, the outlet end of the second delivery pipe 9 is disposed at the bottom of the mixing tank 4, the inlet end of the third delivery pipe 10 is disposed at the top of the mixing tank 4, the outlet end of the third delivery pipe 10 is disposed at the top of the storage tank 4, the third on-off valve 31 is disposed at the top of the mixing tank 4, the upper portion of the gas injection assembly is connected to the third on-off valve 31, the lower portion of the gas injection assembly is disposed at the bottom of the mixing tank 3, and the first on-off valve 6 is disposed on the third delivery pipe 10. The first on-off valve 6 and the third on-off valve 31 are preferably solenoid valves.

[0028] In some embodiments, a second switch valve 7 is further included, and the second delivery pipe 9 is provided with the second switch valve 7. The formic acid level in the formic acid tank 2 is greater than the formic acid level in the mixing tank 3. The second switch valve 7 is preferably a solenoid valve.

[0029] In some embodiments, storage tank 4 includes a storage tank body, a temperature sensor 45, a ceramic heater 46, a heating layer 47, and an insulation layer 48. Temperature sensor 45 is disposed within the storage tank body, heating layer 47 is disposed on the outer layer of the storage tank body, insulation layer 48 is disposed on the outer layer of heating layer 47, and ceramic heater 46 heats heating layer 47. Storage tank 4 heats and insulates gaseous formic acid and nitrogen.

[0030] In some embodiments, a second pressure sensor 41, a second safety pressure relief valve 42, a storage tank inlet pipe 43 and a storage tank outlet pipe 44 are also included; the second pressure sensor 41, the second safety pressure relief valve 42, the storage tank inlet pipe 43 and the storage tank outlet pipe 44 are set on the top of the storage tank body, and the outlet end of the third delivery pipe 10 is connected to the storage tank inlet pipe 43.

[0031] In some embodiments, the formic acid tank 2 includes a first low liquid level sensor 21, a first high liquid level sensor 22 and a formic acid inlet pipe 23; the first low liquid level sensor 21 is set at the lower part of the formic acid tank 2, the first high liquid level sensor 22 is set at the upper part of the formic acid tank 2, and the formic acid inlet pipe 23 is set at the top of the formic acid tank 2.

[0032] In some embodiments, the mixing tank 3 includes a second low liquid level sensor 32, a first safety pressure relief valve 34, a first pressure sensor 35 and a second high liquid level sensor 33. The second low liquid level sensor 32 is arranged at the bottom of the side of the mixing tank 3, the second high liquid level sensor 33 is arranged in the middle of the mixing tank 3, the first pressure sensor 35 is arranged at the top of the mixing tank, and the first safety pressure relief valve 34 is arranged at the top of the mixing tank 3.

[0033] In some embodiments, the gas injection assembly includes a one-way valve, a connecting pipe and a circular pipe; the one-way valve is connected to the connecting pipe and the circular pipe in sequence, the circular pipe is arranged at the inner bottom of the mixing tank 3, and the circular pipe is provided with multiple through holes.

[0034] In some embodiments, a flow meter 5 is further included and the flow meter 5 is set on the first delivery pipe 8.

[0035] In some embodiments, a nitrogen tank 1 and a nitrogen inlet pipe 11 are further included. The nitrogen inlet pipe 11 is set on the top of the nitrogen tank 1, and the inlet end of the first delivery pipe 8 is connected to the nitrogen tank 1.

[0036] A vacuum furnace comprises the formic acid injection system mentioned above.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A formic acid injection system, characterized in that: It includes a formic acid tank, a second delivery pipe, a mixing tank, a storage tank, a gas injection assembly, a first switch valve, a third switch valve and a third delivery pipe; the inlet end of the second delivery pipe is arranged at the bottom of the formic acid tank, the outlet end of the second delivery pipe is arranged at the bottom of the mixing tank, the inlet end of the third delivery pipe is arranged at the top of the mixing tank, the outlet end of the third delivery pipe is arranged at the top of the storage tank, the third switch valve is arranged at the top of the mixing tank, the upper part of the gas injection assembly is connected to the third switch valve, the lower part of the gas injection assembly is arranged at the bottom of the mixing tank, and the first switch valve is arranged on the third delivery pipe.

2. The formic acid injection system according to claim 1, characterized in that: It also includes a second switch valve, the second delivery pipe is provided with the second switch valve, and the formic acid level of the formic acid tank is greater than the formic acid level of the mixing tank.

3. The formic acid injection system according to claim 1, characterized in that: The storage tank includes a storage tank body, a temperature sensor, a ceramic heater, a heating layer and a thermal insulation layer; the temperature sensor is arranged inside the storage tank body, the heating layer is arranged on the outer layer of the storage tank body, the thermal insulation layer is arranged on the outer layer of the heating layer, and the ceramic heater heats the heating layer.

4. The formic acid injection system according to claim 3, characterized in that: It also includes a second pressure sensor, a second safety pressure relief valve, a storage tank inlet pipe and a storage tank outlet pipe; the second pressure sensor, the second safety pressure relief valve, the storage tank inlet pipe and the storage tank outlet pipe are set on the top of the storage tank body, and the outlet end of the third delivery pipe is connected to the storage tank inlet pipe.

5. The formic acid injection system according to claim 1, characterized in that: The formic acid tank includes a first low liquid level sensor, a first high liquid level sensor and a formic acid inlet pipe; the first low liquid level sensor is arranged at the lower part of the formic acid tank, the first high liquid level sensor is arranged at the upper part of the formic acid tank, and the formic acid inlet pipe is arranged at the top of the formic acid tank.

6. The formic acid injection system according to claim 1, characterized in that: The mixing tank includes a second low liquid level sensor, a first safety pressure relief valve, a first pressure sensor and a second high liquid level sensor. The second low liquid level sensor is arranged at the bottom side of the mixing tank, the second high liquid level sensor is arranged in the middle of the mixing tank, the first pressure sensor is arranged at the top of the mixing tank, and the first safety pressure relief valve is arranged at the top of the mixing tank.

7. The formic acid injection system according to claim 1, characterized in that: The gas injection assembly includes a one-way valve, a connecting pipe and a circular pipe; the one-way valve is connected to the connecting pipe and the circular pipe in sequence, the circular pipe is arranged at the inner bottom of the mixing tank, and the circular pipe is provided with a plurality of through holes.

8. The formic acid injection system according to claim 1, characterized in that: It also includes a first delivery pipe and a flow meter, and the flow meter is arranged on the first delivery pipe.

9. The formic acid injection system according to claim 8, characterized in that: It also includes a nitrogen tank and a nitrogen inlet pipe. The nitrogen inlet pipe is arranged on the top of the nitrogen tank, and the inlet end of the first delivery pipe is connected to the nitrogen tank.

10. A vacuum furnace, characterized in that: The formic acid injection system comprises the formic acid injection system according to any one of claims 1 to 9.

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