Nitrogen circulation refrigeration device

Abstract

The invention belongs to the technical field of refrigeration devices, and particularly relates to a nitrogen circulation refrigeration device. Comprising a siphoning type condensation mechanism, a radiator, a conveying pump, an expansion machine, an evaporator, a compressor and a first liquid nitrogen tank, the siphoning type condensation mechanism comprises a mounting box, a second liquid nitrogen tank and a condenser, the second liquid nitrogen tank and the condenser are arranged in the mounting box, and a liquid nitrogen outlet in the bottom end of the second liquid nitrogen tank communicates with a cold source inlet in the bottom end of the condenser; a cold source outlet in the top end of the condenser communicates with the upper portion of the second liquid nitrogen tank, and a nitrogen outlet in the top of the second liquid nitrogen tank sequentially communicates with a radiator, a conveying pump, an expansion machine, an evaporator, a compressor and the first liquid nitrogen tank through pipelines and finally communicates with a liquid nitrogen inlet in the upper portion of the second liquid nitrogen tank. And a throttle valve is arranged on the pipeline between the first liquid nitrogen tank and the second liquid nitrogen tank. According to the invention, recovery and reutilization of nitrogen can be realized, so that the production cost is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of refrigeration devices, and in particular relates to a nitrogen circulation refrigeration device. Background Art

[0002] As a new development direction of the modern chemical industry, stable isotopes have unique and efficient applications in the fields of medicine, life sciences, agriculture, and analytical method improvement. In the prior art, there are already a variety of stable isotope production methods, such as thermal diffusion method, gas diffusion method, chemical exchange method, cryogenic distillation method, laser method, etc. Among them, cryogenic distillation method is the main method for producing stable isotopes in industry, but because the vapor pressure difference between different isotopic components of a single substance is very small, a multi-tower cascade operation must be adopted to obtain a high-abundance target isotope, and in order to maintain the low temperature of the multi-stage distillation tower, a large amount of liquid nitrogen is required for temperature control, and liquid nitrogen will be directly discharged after heat exchange in the condenser, which undoubtedly increases the consumption of energy and causes the current situation of high production cost. Therefore, it is urgent to design a nitrogen circulation refrigeration device that can be used for isotope cryogenic distillation. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a nitrogen circulation refrigeration device, and specifically discloses the following technical solutions:

[0004] A nitrogen circulation refrigeration device comprises a siphon condensing mechanism, a radiator, a delivery pump, an expander, an evaporator, a compressor and a first liquid nitrogen tank, wherein the siphon condensing mechanism comprises an installation box and a second liquid nitrogen tank and a condenser arranged in the installation box, wherein a liquid nitrogen outlet at the bottom end of the second liquid nitrogen tank is communicated with a cold source inlet at the bottom end of the condenser, and a cold source outlet at the top end of the condenser is communicated with an upper part of the second liquid nitrogen tank, and a nitrogen outlet at the top of the second liquid nitrogen tank is sequentially connected to the radiator, the delivery pump, the expander, the evaporator, the compressor and the first liquid nitrogen tank through a pipeline and finally communicated with the liquid nitrogen inlet at the upper part of the second liquid nitrogen tank, and a throttle valve is arranged on the pipeline between the first liquid nitrogen tank and the second liquid nitrogen tank.

[0005] Furthermore, a lifting mechanism is provided in the installation box, and the lifting mechanism includes a driving motor, and the driving motor is fixedly provided on the top wall of the installation box, and a vertically downward lead screw is fixedly connected to the output shaft of the driving motor, and the bottom end of the lead screw is rotatably connected to the bottom wall of the installation box, and a lifting plate is threadedly connected to the lead screw, and the second liquid nitrogen tank is fixedly provided on the lifting plate. A guide column parallel to the lead screw is also fixedly provided in the installation box, and the two ends of the guide column are respectively fixedly connected to the top wall and the bottom wall of the installation box, and the guide column passes through the lifting plate and is slidably connected to the lifting plate, and the condenser is fixedly provided on the inner wall of the installation box.

[0006] Furthermore, the pipelines are all made of stainless steel corrugated hoses.

[0007] Furthermore, the condenser includes an outer shell, in which a first partition and a second partition are arranged in sequence from top to bottom, the first partition and the second partition are arranged in parallel, and the first partition and the second partition divide the internal space of the outer shell into an upper cavity, a middle cavity and a lower cavity in sequence, the top of the outer shell is provided with a cold source outlet connected to the upper cavity, the bottom of the outer shell is provided with a cold source inlet connected to the lower cavity, the upper side wall of the outer shell is provided with an air inlet connected to the upper part of the middle cavity, the lower side wall of the outer shell is provided with an air outlet connected to the lower part of the middle cavity, a plurality of heat exchange tubes are connected between the first partition and the second partition, and a through hole connected to the heat exchange tube is opened at the position corresponding to each heat exchange tube on the first partition and the second partition.

[0008] Furthermore, a support column is fixedly connected between the middle part of the first partition and the middle part of the second partition, a spiral plate is fixedly connected to the outer wall of the support column, the inner side of the spiral plate is fixedly connected to the side wall of the support column, the outer side of the spiral plate is fixedly connected to the inner wall of the middle cavity, and a plurality of heat exchange tubes are arranged through the spiral plate.

[0009] Furthermore, the second liquid nitrogen tank is connected to a liquid level detector.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The present invention can realize the recovery and reuse of nitrogen, thereby greatly reducing the production cost;

[0012] The siphon type condensing mechanism in the present invention can realize the liquid nitrogen transportation between the second liquid nitrogen tank and the condenser by siphon action without external force driving, so it can save more energy. At the same time, the height difference between the second liquid nitrogen tank and the condenser can be adjusted by the lifting mechanism, so as to adjust the siphon speed and further adjust the cooling rate.

[0013] The condenser of the present invention is provided with heat exchange tubes and spiral plates, which can effectively increase the heat exchange area and heat exchange time between liquid nitrogen and the gas to be cooled, thereby significantly improving the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention.

[0015] Figure 2 It is a schematic diagram of the internal structure of the siphon type condensation mechanism in the present invention.

[0016] Figure 3 It is a schematic diagram of the internal structure of the condenser in the present invention.

[0017] 1- radiator, 2- delivery pump, 3- expander, 4- evaporator, 5- compressor, 6- first liquid nitrogen tank, 7- installation box, 8- second liquid nitrogen tank, 9- condenser, 91- outer shell, 92- first partition, 93- second partition, 94- heat exchange tube, 95- support column, 96- spiral plate, 10- throttle valve, 11- drive motor, 12- lead screw, 13- guide column, 14- lifting plate, 15- liquid level detector. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Reference Figure 1-3 A nitrogen circulation refrigeration device comprises a siphon condensing mechanism, a radiator 1, a delivery pump 2, an expander 3, an evaporator 4, a compressor 5 and a first liquid nitrogen tank 6, wherein the siphon condensing mechanism comprises an installation box 7 and a second liquid nitrogen tank 8 and a condenser 9 arranged in the installation box 7, wherein the liquid nitrogen outlet at the bottom of the second liquid nitrogen tank 8 is communicated with the cold source inlet at the bottom of the condenser 9, the cold source outlet at the top of the condenser 9 is communicated with the upper part of the second liquid nitrogen tank 8, the nitrogen outlet at the top of the second liquid nitrogen tank 8 is sequentially connected to the radiator 1, the delivery pump 2, the expander 3, the evaporator 4, the compressor 5 and the first liquid nitrogen tank 6 through a pipeline and finally communicated with the liquid nitrogen inlet at the upper part of the second liquid nitrogen tank 8, and a throttle valve 10 is arranged on the pipeline between the first liquid nitrogen tank 6 and the second liquid nitrogen tank 8.

[0020] The liquid nitrogen is converted into nitrogen gas after passing through the siphon condensation mechanism, and the nitrogen gas is discharged from the nitrogen outlet at the top of the second liquid nitrogen tank 8, and then passes through the radiator 1, the delivery pump 2, the expander 3, the evaporator 4 and the compressor 5 in sequence, and is converted into liquid nitrogen again under the action of the compressor 5 of the expander 3 and stored in the first liquid nitrogen tank 6.

[0021] In this embodiment, a lifting mechanism is provided in the installation box 7, and the lifting mechanism includes a driving motor 11, and the driving motor 11 is fixedly arranged on the top wall of the installation box 7. A vertically downward lead screw 12 is fixedly connected to the output shaft of the driving motor 11, and the bottom end of the lead screw 12 is rotatably connected to the bottom wall of the installation box 7. A lifting plate 14 is threadedly connected to the lead screw 12, and the second liquid nitrogen tank 8 is fixedly arranged on the lifting plate 14. A guide column 13 parallel to the lead screw 12 is also fixedly arranged in the installation box 7, and the two ends of the guide column 13 are respectively fixedly connected to the top wall and the bottom wall of the installation box 7, and the guide column 13 passes through the lifting plate 14 and is slidably connected to the lifting plate 14. The condenser 9 is fixedly arranged on the inner wall of the installation box 7. The driving motor 11 drives the lead screw 12 to rotate, which can drive the lifting plate 14 to move up and down. The lifting plate 14 drives the second liquid nitrogen tank 8 to move up and down, which can adjust the height difference between the second liquid nitrogen tank 8 and the condenser 9, thereby adjusting the siphon speed, and finally realizing the adjustment of the cooling rate of the gas to be cooled.

[0022] In this embodiment, the pipelines are all made of stainless steel corrugated hoses.

[0023] In this embodiment, the condenser 9 includes an outer shell 91, in which a first partition 92 and a second partition 93 are sequentially arranged from top to bottom. The first partition 92 and the second partition 93 are arranged in parallel, and the first partition 92 and the second partition 93 divide the internal space of the outer shell 91 into an upper cavity, a middle cavity and a lower cavity in sequence. The top of the outer shell 91 is provided with a cold source outlet connected to the upper cavity, and the bottom of the outer shell 91 is provided with a cold source inlet connected to the lower cavity. The upper side wall of the outer shell 91 is provided with an air inlet connected to the upper part of the middle cavity, and the lower side wall of the outer shell 91 is provided with an air outlet connected to the lower part of the middle cavity. A plurality of heat exchange tubes 94 are connected between the first partition 92 and the second partition 93, and a through hole connected to the heat exchange tube 94 is opened at the position corresponding to each heat exchange tube 94 on the first partition 92 and the second partition 93. The liquid nitrogen in the second liquid nitrogen tank 8 enters the lower cavity from the cold source inlet at the bottom of the condenser 9, and then enters the upper cavity through the heat exchange tube 94. In the process of passing through the heat exchange tube 94, the liquid nitrogen exchanges heat with the gas to be cooled in the middle cavity outside the heat exchange tube 94 and becomes nitrogen, which enters the upper cavity. The nitrogen returns to the second liquid nitrogen tank 8 through the cold source outlet, and finally enters the radiator 1 from the nitrogen outlet at the top of the second liquid nitrogen tank 8.

[0024] In this embodiment, a support column 95 is fixedly connected between the middle of the first baffle 92 and the middle of the second baffle 93, and a spiral plate 96 is fixedly connected to the outer wall of the support column 95. The structure of the support column 95 and the spiral plate 96 can refer to the structure of the auger. The inner side of the spiral plate 96 is fixedly connected to the side wall of the support column 95, and the outer side of the spiral plate 96 is fixedly connected to the inner side wall of the middle cavity. A plurality of heat exchange tubes 94 are arranged through the spiral plate 96. The arrangement of the spiral plate 96 can significantly increase the travel length and residence time of the gas to be cooled in the middle cavity, so that the gas to be cooled can fully exchange heat with the liquid nitrogen in the heat exchange tube 94.

[0025] In this embodiment, the second liquid nitrogen tank 8 is connected to a liquid level detector 15, which can detect the liquid level height in the second liquid nitrogen tank 8 in real time, and control the flow rate of liquid nitrogen flowing from the first liquid nitrogen tank 6 to the second liquid nitrogen tank 8 through the throttle valve 10, thereby controlling and adjusting the liquid level height in the second liquid nitrogen tank 8 in real time.

[0026] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A nitrogen cycle refrigeration device, characterized in that: The invention comprises a siphon condensing mechanism, a radiator, a delivery pump, an expander, an evaporator, a compressor and a first liquid nitrogen tank. The siphon condensing mechanism comprises an installation box and a second liquid nitrogen tank and a condenser arranged in the installation box. The liquid nitrogen outlet at the bottom end of the second liquid nitrogen tank is communicated with the cold source inlet at the bottom end of the condenser, and the cold source outlet at the top end of the condenser is communicated with the upper part of the second liquid nitrogen tank. The nitrogen outlet at the top of the second liquid nitrogen tank is sequentially connected to the radiator, the delivery pump, the expander, the evaporator, the compressor and the first liquid nitrogen tank through a pipeline and finally communicated with the liquid nitrogen inlet at the upper part of the second liquid nitrogen tank. A throttle valve is arranged on the pipeline between the first liquid nitrogen tank and the second liquid nitrogen tank.

2. A nitrogen cycle refrigeration device according to claim 1, characterized in that: A lifting mechanism is provided in the installation box, and the lifting mechanism includes a driving motor, and the driving motor is fixedly provided on the top wall of the installation box, and a vertically downward lead screw is fixedly connected to the output shaft of the driving motor, and the bottom end of the lead screw is rotatably connected to the bottom wall of the installation box, and a lifting plate is threadedly connected to the lead screw, and the second liquid nitrogen tank is fixedly provided on the lifting plate. A guide column parallel to the lead screw is also fixedly provided in the installation box, and the two ends of the guide column are respectively fixedly connected to the top wall and the bottom wall of the installation box, and the guide column passes through the lifting plate and is slidably connected to the lifting plate, and the condenser is fixedly provided on the inner wall of the installation box.

3. A nitrogen cycle refrigeration device according to claim 2, characterized in that: The pipelines are all made of stainless steel corrugated hoses.

4. A nitrogen cycle refrigeration device according to claim 2, characterized in that: The condenser includes an outer shell, in which a first partition and a second partition are arranged in sequence from top to bottom, the first partition and the second partition are arranged in parallel, and the first partition and the second partition divide the internal space of the outer shell into an upper cavity, a middle cavity and a lower cavity in sequence, the top of the outer shell is provided with a cold source outlet connected to the upper cavity, the bottom of the outer shell is provided with a cold source inlet connected to the lower cavity, the upper side wall of the outer shell is provided with an air inlet connected to the upper part of the middle cavity, and the lower side wall of the outer shell is provided with an air outlet connected to the lower part of the middle cavity, a plurality of heat exchange tubes are connected between the first partition and the second partition, and a through hole connected to the heat exchange tube is opened at the position corresponding to each heat exchange tube on the first partition and the second partition.

5. A nitrogen cycle refrigeration device according to claim 4, characterized in that: A support column is fixedly connected between the middle part of the first partition and the middle part of the second partition, a spiral plate is fixedly connected to the outer wall of the support column, the inner side of the spiral plate is fixedly connected to the side wall of the support column, the outer side of the spiral plate is fixedly connected to the inner wall of the middle cavity, and a plurality of heat exchange tubes are arranged through the spiral plate.

6. A nitrogen cycle refrigeration device according to claim 1, characterized in that: The second liquid nitrogen tank is connected to a liquid level detector.

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