Automatically-controlled nitrogen-saving device

Abstract

The invention discloses an automatic control nitrogen saving device which comprises a quenching furnace, a vaporization tank, a liquid nitrogen storage tank, a nitrogen storage tank, a gas-liquid separation tank, a filter, a heat exchanger and a condenser, an exhaust port of the quenching furnace is communicated with a medium inlet of the vaporization tank, a gas inlet of the quenching furnace is communicated with the nitrogen storage tank, the nitrogen storage tank is communicated with the vaporization tank, and the liquid nitrogen storage tank is communicated with the gas-liquid separation tank. The vaporization tank is communicated with the liquid nitrogen storage tank, the liquid nitrogen storage tank is communicated with a liquid phase outlet of the gas-liquid separation tank, a medium outlet of the vaporization tank is communicated with the filter, the filter is communicated with the heat exchanger, the heat exchanger is communicated with the condenser, and the condenser is communicated with a gas phase outlet of the gas-liquid separation tank; particle impurities in gas are filtered out through the filter, then the gas is subjected to heat exchange and cooling through the heat exchanger, and finally the gas is subjected to secondary heat exchange and cooling through the condenser, so that nitrogen in the gas is condensed into liquid nitrogen, the nitrogen in the quenching furnace can be recycled, and the usage amount of the nitrogen is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of nitrogen saving devices, and in particular to an automatically controlled nitrogen saving device. Background Art

[0002] A nitrogen-saving device refers to a device or system used to save nitrogen usage. During the vacuum quenching process, the nitrogen-saving device can reuse the remaining nitrogen in the quenching furnace through the design of multi-way pipelines and one-way valves, thereby reducing nitrogen waste.

[0003] The vacuum quenching furnace in the prior art generates a large amount of high heat when in use, and the continuous high heat is directly discharged, thereby affecting the surrounding environment and causing waste of resources. In view of the above defects, it is necessary to design an automatically controlled nitrogen saving device. Summary of the invention

[0004] The object of the present invention is to provide an automatically controlled nitrogen saving device to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: an automatically controlled nitrogen-saving device, comprising a quenching furnace, a vaporizer, a liquid nitrogen storage tank, a nitrogen storage tank, a gas-liquid separation tank, a filter, a heat exchanger and a condenser, wherein the exhaust port of the quenching furnace is connected to the medium inlet of the vaporizer through a first connecting pipe, the air inlet of the quenching furnace is connected to the nitrogen storage tank through a second connecting pipe, the nitrogen storage tank is connected to the vaporizer through a third connecting pipe, the vaporizer is connected to the liquid nitrogen storage tank through a fourth connecting pipe, the liquid nitrogen storage tank is connected to the liquid phase outlet of the gas-liquid separation tank through a fifth connecting pipe, the medium outlet of the vaporizer is connected to the filter through a sixth connecting pipe, the filter is connected to the heat exchanger through a seventh connecting pipe, the heat exchanger is connected to the condenser through an eighth connecting pipe, the condenser is connected to the gas phase outlet of the gas-liquid separation tank through a ninth connecting pipe, and the liquid phase inlet of the gas-liquid separation tank is connected to the eighth connecting pipe through a tenth connecting pipe.

[0006] Preferably, a sealing door is rotatably connected to one end of the quenching furnace, a temperature sensor and a nitrogen concentration sensor are installed inside the quenching furnace, a drainage tube is also installed inside the quenching furnace, a placement rack is installed inside the drainage tube, a first diversion channel is arranged between the drainage tube and the quenching furnace, a drainage block is installed at one end of the drainage tube, a second diversion channel is arranged between the drainage block and the drainage tube, and a plurality of drainage tubes connected with the second connecting pipe are arranged inside the drainage block.

[0007] Preferably, an electric flow valve is installed on the second connecting pipe, and the first air pump is connected to the second connecting pipe. The left end of the drainage tube is a closed end wall, the right end of the drainage tube is a tube mouth, the upper and lower ends of the drainage tube are annular end walls, and a plurality of first diversion holes are spaced apart on the annular end wall of the drainage tube, and a plurality of second diversion holes are spaced apart on the left end wall of the drainage tube, and the plurality of second diversion holes are connected to the second diversion channel, and a plurality of heating tubes are evenly installed on the inner wall of the drainage tube.

[0008] Preferably, a heat exchange tube bent in an S shape is provided inside the vaporizer, one end of the heat exchange tube is connected to the first connecting tube, a first one-way valve is installed on the first connecting tube, a second air pump is connected to the first connecting tube, the other end of the heat exchange tube is connected to the sixth connecting tube, a second one-way valve is installed on the sixth connecting tube, a third air pump is connected to the sixth connecting tube, spiral heat-conducting fins are formed around the heat exchange tube and coiled around the heat exchange tube, a spiral channel is formed between the heat-conducting fins and the heat exchange tube, and a pressure gauge is installed on the top of the vaporizer.

[0009] Preferably, the vaporizer is connected to a third connecting pipe, a third one-way valve is installed on the third connecting pipe, a fourth air pump is connected to the third connecting pipe, the vaporizer is also connected to a fourth connecting pipe, a fourth one-way valve is installed on the fourth connecting pipe, and the first low-temperature circulation pump is connected to the fourth connecting pipe.

[0010] Preferably, an annular spray rack is provided inside the gas-liquid separation tank, and the annular spray rack includes four arc-shaped spray pipes and a three-way joint for connecting adjacent arc-shaped spray pipes. The arc-shaped spray pipe is connected to the branch pipe through the three-way joint, and the branch pipe is connected to the second connecting pipe through a connecting head. A number of spray holes with openings facing downwards are opened along the length direction of the arc-shaped spray pipe.

[0011] Preferably, a drainage assembly is provided below the annular spray rack, the drainage assembly includes a drainage switch and a drainage pipe, the liquid level switch is used to control the on-off of the drainage pipe according to the liquid level height of the liquid in the gas-liquid separation tank, the liquid level switch includes a floating ball, a conical piston is installed at the bottom of the floating ball, guide blocks are installed on both sides of the floating ball, the guide blocks are slidably set on the guide rod, and a limit baffle is installed on the top of the guide rod.

[0012] Preferably, the pointed cone at the bottom end of the conical piston extends into the top of the drain pipe to seal the drain pipe, a drain port is provided below the conical piston, the drain port is provided in the middle of the bottom end of the gas-liquid separation tank, a drain pipe connected with the drain port is provided on the gas-liquid separation tank, the drain pipe is connected with the fifth connecting pipe, a second low-temperature circulation pump is connected to the drain pipe, an exhaust pipe is provided on the top of the gas-liquid separation tank, the exhaust pipe is connected with the condenser, a fifth one-way valve is installed on the exhaust pipe, and a fifth air pump is connected to the exhaust pipe.

[0013] Preferably, a frame is provided above the annular spray rack, a cavity is provided in the middle of the frame, a plurality of baffles are provided in the cavity, the baffles include a vertical portion and a bending portion connected in sequence, the baffles are in a trapezoidal structure, a gas channel is formed between each adjacent two baffles, a plurality of liquid collecting blocks are provided on the bending portions at the upper and lower ends of each gas channel, and the plurality of liquid collecting blocks are evenly spaced on the bending portions.

[0014] Preferably, a filter screen is provided at the bottom of the frame, a fixing ring is provided above the frame, a fixing column is provided in the middle of the fixing ring, a plurality of swirl plates are provided between the fixing column and the fixing ring, and a plurality of guide holes are evenly opened on the edge of the fixing ring.

[0015] Compared with the prior art, the technical solution provided by the present invention has at least the following technical effects or advantages:

[0016] 1. The present invention filters out particulate impurities in the gas through a filter, and the filtered gas first passes through a heat exchanger, which exchanges heat and cools the gas, thereby reducing the cooling pressure of the condenser. The gas then passes through the condenser for a second heat exchange and cooling, so that the gas is further condensed, and the nitrogen in the gas is condensed into liquid nitrogen, so that the nitrogen in the quenching furnace can be recycled and reused, reducing the amount of nitrogen used and saving the energy consumption of the quenching furnace;

[0017] 2. The present invention detects the nitrogen concentration in the quenching furnace through a nitrogen concentration sensor, and feeds back the detected concentration value to the PLC controller. The PLC controller adjusts the input nitrogen flow rate according to the feedback of the nitrogen concentration sensor and outputs a flow control signal. The electric flow valve receives the flow control signal output by the PLC controller, and controls the nitrogen flow entering the quenching furnace according to the flow control signal, thereby being able to accurately control and adjust the nitrogen flow rate, avoid nitrogen waste, and achieve the effect of saving nitrogen;

[0018] 3. The present invention can greatly increase the heat exchange area and improve the heating effect of liquid nitrogen through the S-shaped bent heat exchange tube and the spiral heat-conducting fins coiled on the heat exchange tube, which is beneficial to improving the vaporization efficiency of liquid nitrogen. In addition, during the vaporization process of liquid nitrogen, nitrogen and dense fog are generated. The nitrogen and dense fog flow upward along the heat exchange tube, the spiral heat-conducting fins and the spiral channel to form a vortex. During the flow process, the dense fog hits the heat exchange tube and the spiral heat-conducting fin to form droplets. The nitrogen continues to flow upward along the spiral channel. Under the action of gravity, the droplets flow along the heat exchange tube and the spiral heat-conducting fins and flow to the bottom of the vaporizer. Secondary vaporization is performed through the heat exchange tube, so that the liquid nitrogen is vaporized more thoroughly and the vaporization effect of the liquid nitrogen is improved.

[0019] 4. The present invention uses a first air pump to draw nitrogen from a nitrogen storage tank into a quenching furnace. The nitrogen flows into a first diversion channel and a second diversion channel respectively through a plurality of drainage pipes. The nitrogen in the first diversion channel enters the drainage tube through a plurality of first diversion holes, so that the nitrogen is evenly diffused and diverted in the drainage tube. At the same time, the nitrogen in the second diversion channel enters the drainage tube through a plurality of second diversion holes, so that the nitrogen is evenly diffused and diverted in the drainage tube, thereby effectively improving the uniformity of nitrogen in the quenching furnace, thereby improving the quenching effect of the metal workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 It is a schematic diagram of the internal structure of the quenching furnace in the present invention;

[0023] Figure 3 It is a schematic diagram of the internal structure of the vaporizer in the present invention;

[0024] Figure 4 This is a schematic diagram of the internal structure of the gas-liquid separation tank in the present invention;

[0025] Figure 5 It is a schematic diagram of the internal structure of the fixing ring in the present invention.

[0026] In the attached figure:

[0027] 1. Quenching furnace; 2. First connecting pipe; 3. Vaporization tank; 4. Second connecting pipe; 5. Liquid nitrogen storage tank; 6. Third connecting pipe; 7. Fourth connecting pipe; 8. Nitrogen storage tank; 9. Fifth connecting pipe; 10. Gas-liquid separation tank; 11. Sixth connecting pipe; 12. Filter; 13. Seventh connecting pipe; 14. Heat exchanger; 15. Eighth connecting pipe; 16. Condenser; 17. Ninth connecting pipe; 18. Tenth connecting pipe; 19. Sealing door; 20. Temperature sensor; 21. Nitrogen concentration sensor; 22. Drainage tube; 23. Placement rack; 24. First shunt channel; 25. Drainage block; 26. Second shunt channel; 27. Drainage pipe; 28. First shunt hole; 29. ​​Second shunt hole; 30. Heating pipe; 31. Electric flow valve; 32. First air pump; 33. Heat exchange pipe; 34. First one-way valve; 35. Second air pump; 36. Second one-way valve valve; 37, third air pump; 38, spiral heat conducting fin; 39, third one-way valve; 40, fourth air pump; 41, fourth one-way valve; 42, first low-temperature circulation pump; 43, annular spray rack; 431, arc spray pipe; 432, three-way joint; 433, branch pipe; 434, connector; 435, spray hole; 44, drainage assembly; 441, drainage pipe; 442, floating ball; 443, tapered piston; 444, Guide block; 445, guide rod; 446, limit baffle; 447, second low-temperature circulation pump; 448, liquid level sensor; 45, exhaust pipe; 46, fifth one-way valve; 47, fifth air pump; 48, frame; 49, baffle; 491, vertical portion; 492, bending portion; 493, liquid collecting block; 50, gas channel; 51, filter screen; 52, fixing ring; 53, fixing column; 54, swirl plate; 55, guide hole. DETAILED DESCRIPTION

[0028] 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.

[0029] See also Figure 1-5As shown, the present invention provides a technical solution: an automatically controlled nitrogen saving device, comprising a quenching furnace 1, a vaporizer 3, a liquid nitrogen storage tank 5, a nitrogen storage tank 8, a gas-liquid separation tank 10, a filter 12, a heat exchanger 14 and a condenser 16, the exhaust port of the quenching furnace 1 is connected to the medium inlet of the vaporizer 3 through a first connecting pipe 2, the air inlet of the quenching furnace 1 is connected to the nitrogen storage tank 5 through a second connecting pipe 4, the nitrogen storage tank 5 is connected to the vaporizer 3 through a third connecting pipe 6, and the vaporizer 3 is connected to the liquid nitrogen through a fourth connecting pipe 7. The storage tank 8 and the liquid nitrogen storage tank 8 are connected to the liquid phase outlet of the gas-liquid separation tank 10 through the fifth connecting pipe 9, the medium outlet of the vaporization tank 3 is connected to the filter 12 through the sixth connecting pipe 11, the filter 12 is connected to the heat exchanger 14 through the seventh connecting pipe 13, the heat exchanger 14 is connected to the condenser 16 through the eighth connecting pipe 15, the condenser 16 is connected to the gas phase outlet of the gas-liquid separation tank 10 through the ninth connecting pipe 17, and the liquid phase inlet of the gas-liquid separation tank 10 is connected to the eighth connecting pipe 15 through the tenth connecting pipe 18. The particulate impurities in the gas are filtered out by the filter 12, and the filtered gas first passes through the heat exchanger 14, and the heat exchanger 14 performs heat exchange and cooling on the gas, which can reduce the cooling pressure of the condenser 16, and then the gas is subjected to a second heat exchange and cooling through the condenser 16, so that the gas is further condensed, and the nitrogen in the gas is condensed into liquid nitrogen, so that the nitrogen in the quenching furnace 1 can be recycled and reused, reducing the use of nitrogen and saving the energy consumption of the quenching furnace 1.

[0030] One end of the quenching furnace 1 in this embodiment is rotatably connected with a sealing door 19, a temperature sensor 20 and a nitrogen concentration sensor 21 are installed inside the quenching furnace 1, and the temperature sensor 20 and the nitrogen concentration sensor 21 are electrically connected to the PLC controller respectively. A drainage tube 22 is also installed inside the quenching furnace 1, and a placement rack 23 is installed inside the drainage tube 22. A first shunt channel 24 is arranged between the drainage tube 22 and the quenching furnace 1, a drainage block 25 is installed at one end of the drainage tube 22, and a second shunt channel 26 is arranged between the drainage block 25 and the drainage tube 22, and a plurality of drainage tubes 27 connected with the second connecting pipe 4 are arranged inside the drainage block 25, and an electric flow valve 31 is installed on the second connecting pipe 4. The flow valve 31 is electrically connected to the PLC controller, the second connecting pipe 4 is connected to the first air pump 32, the drainage tube 27 is an L-shaped bent pipe, the drainage tube 27 is respectively connected to the first diversion channel 24 and the second diversion channel 26, the left end of the drainage tube 22 is a closed end wall, the right end of the drainage tube 22 is a tube mouth, the upper and lower ends of the drainage tube 22 are annular end walls, a plurality of first diversion holes 28 are spaced apart on the annular end wall of the drainage tube 22, and the plurality of first diversion holes 28 are connected to the first diversion channel 24, a plurality of second diversion holes 29 are spaced apart on the left end wall of the drainage tube 22, and the plurality of second diversion holes 29 are connected to the second diversion channel 26, and a plurality of heating tubes 30 are evenly installed on the inner wall of the drainage tube 22. The nitrogen concentration sensor 21 is used to detect the nitrogen concentration in the quenching furnace 1 and feed back the detected concentration value to the PLC controller. The PLC controller adjusts the input nitrogen flow rate according to the feedback of the nitrogen concentration sensor 21 and outputs a flow control signal. The electric flow valve 31 receives the flow control signal output by the PLC controller and controls the nitrogen flow entering the quenching furnace 1 according to the flow control signal, thereby being able to accurately control and adjust the nitrogen flow rate, avoid nitrogen waste, and achieve the effect of saving nitrogen.

[0031] The vaporizer 3 in this embodiment is internally provided with an S-shaped heat exchange tube 33, one end of the heat exchange tube 33 is connected to the first connecting tube 2, a first one-way valve 34 is installed on the first connecting tube 2, a second air pump 35 is connected to the first connecting tube 2, the other end of the heat exchange tube 33 is connected to the sixth connecting tube 11, a second one-way valve 36 is installed on the sixth connecting tube 11, a third air pump 37 is connected to the sixth connecting tube 11, a spiral heat-conducting fin 38 is formed around the heat exchange tube 33 and is wound around the heat exchange tube 33, and a spiral channel is formed between the spiral heat-conducting fin 38 and the heat exchange tube 33. The S-shaped bent heat exchange tube 33 and the spiral heat-conducting fin 38 wound around the heat exchange tube 33 can greatly increase the heat exchange area, improve the heating effect of liquid nitrogen, and help improve the vaporization efficiency of liquid nitrogen. In addition, during the vaporization process of liquid nitrogen, nitrogen and dense fog are generated. The nitrogen and dense fog flow upward along the heat exchange tube 33, the spiral heat-conducting fin 38 and the spiral channel to form a vortex. During the flow process, the dense fog hits the heat exchange tube 33 and the spiral heat-conducting fin 38 to form droplets. The nitrogen continues to flow upward along the spiral channel. Under the action of gravity, the droplets flow along the heat exchange tube 33 and the spiral heat-conducting fin 38, and flow to the bottom of the vaporizer 3, and are secondary vaporized through the heat exchange tube 33, so that the liquid nitrogen is vaporized more thoroughly, thereby improving the vaporization effect of the liquid nitrogen.

[0032] A pressure gauge is installed on the top of the vaporizer 3 in this embodiment, and the pressure gauge extends to the interior of the vaporizer 3. The air pressure inside the vaporizer 3 is monitored by the pressure gauge to prevent the air pressure inside the vaporizer 3 from being too high and causing damage to the vaporizer 3. The vaporizer 3 is connected to the third connecting pipe 6, and a third one-way valve 39 is installed on the third connecting pipe 6. The third connecting pipe 6 is connected to a fourth air pump 40. The vaporizer 3 is also connected to the fourth connecting pipe 7, and a fourth one-way valve 41 is installed on the fourth connecting pipe 7. The fourth connecting pipe 7 is connected to a first low-temperature circulation pump 42.

[0033] The gas-liquid separation tank 10 in this embodiment is internally provided with an annular spray rack 43, which includes four arc-shaped spray pipes 431 and a three-way joint 432 for connecting adjacent arc-shaped spray pipes 431. The arc-shaped spray pipes 431 are connected to the branch pipes 433 via the three-way joints 432, and the branch pipes 433 are connected to the second connecting pipe 17 via the connector 434. A plurality of spray holes 435 with openings facing downwards are provided along the length direction of the arc-shaped spray pipes 431.

[0034] A drain assembly 44 is provided below the annular spray rack 43 in this embodiment. The drain assembly 44 includes a drain switch and a drain pipe 441. The liquid level switch is used to control the on and off of the drain pipe 441 according to the liquid level height of the liquid in the gas-liquid separation tank 10. The liquid level switch includes a floating ball 442. A conical piston 443 is installed at the bottom of the floating ball 442. Guide blocks 444 are installed on both sides of the floating ball 442. The guide blocks 444 are slidably arranged on the guide rod 445. A limit baffle 446 is installed on the top of the guide rod 445. A drain port is provided below the conical piston 443. The drain port is arranged in the middle of the bottom end of the gas-liquid separation tank 10. A drain pipe 441 connected to the drain port is provided on the gas-liquid separation tank 10, and the bottom tip of the conical piston 443 extends into the drain port to block the drain pipe 441 to prevent the uncondensed gas in the gas-liquid separation tank 10 from being sucked into the nitrogen storage tank 8. The drain pipe 441 is connected to the fifth connecting pipe 9, and a second low-temperature circulation pump 447 is connected to the drain pipe 441. A liquid level sensor 448 is provided in the gas-liquid separation tank 10. An exhaust pipe 45 is provided on the top of the gas-liquid separation tank 10, and the exhaust pipe 45 is connected to the condenser 16. A fifth one-way valve 46 is installed on the exhaust pipe 45, and a fifth air pump 47 is connected to the exhaust pipe 45.

[0035] A frame 48 is provided above the annular spray rack 43 in this embodiment, a cavity is provided in the middle of the frame 48, a plurality of baffles 49 are provided in the cavity, the baffles 49 include a vertical portion 491 and a bent portion 492 connected in sequence, the baffles 49 are of a trapezoidal structure, a gas channel 50 is formed between each two adjacent baffles 49, a plurality of liquid collecting blocks 493 are provided on the bent portions 462 at the upper and lower ends of each gas channel 50, the liquid collecting blocks 493 are of a conical structure, and a plurality of liquid collecting blocks 493 are evenly spaced on the bent portions 492, a filter screen 51 is provided at the bottom of the frame 48, a fixing ring 52 is provided above the frame 48, a fixing column 53 is provided in the middle of the fixing ring 52, a plurality of swirl plates 54 are provided between the fixing column 53 and the fixing ring 52, and a plurality of guide holes 55 are evenly opened on the edge of the fixing ring 52. The uncondensed gas passes through the filter screen 51 at the lower end of the frame 48. The filter screen 51 can block some liquid droplets in the uncondensed gas and perform preliminary separation on the uncondensed gas. The separated liquid droplets are discharged along the filter screen 51. The gas carries the unseparated liquid droplets and continues to move upward along the gas channel 50. When the gas passes through the bend of the baffle 49, the moving direction will change. The liquid droplets with larger inertia force in the gas will hit the bend 492. The liquid collecting block 493 on the bend 492 can make the liquid part attached to the bend 492 flow along the liquid collecting block 493. 93 moves downward to further separate the uncondensed gas, and the gas entrained with the unseparated liquid droplets continues to move upward into the fixed ring 52. The swirl plate 54 can make the gas-liquid mixed airflow form a strong swirling airflow in the fixed ring 52, which is beneficial for the liquid phase in the mixed airflow to adhere to the surface under the action of centrifugal force and inertial force. At the same time, a plurality of guide holes 55 are evenly opened on the edge of the swirl plate 54, which can ensure that the liquid separated from the top of the gas-liquid separation tank 10 flows down quickly along the inner wall of the gas-liquid separation tank 10, thereby improving the gas-liquid separation effect.

[0036] The working principle and use method of the present invention include as follows:

[0037] 1) Waste heat recovery: The metal workpiece is placed on the placement rack 23 of the quenching furnace 1, and the heating tube 30 is operated to heat the metal workpiece inside the quenching furnace 1. After heating and maintaining for a period of time, the electric flow valve 34 and the first air pump 35 are opened. The first air pump 35 can transport the high-temperature gas inside the quenching furnace 1 to the heat exchange tube 33 of the vaporizer 3. The high-temperature gas in the heat exchange tube 33 heats the liquid nitrogen inside the vaporizer 3, so that the liquid nitrogen in the vaporizer 3 is heated and vaporized. During the vaporization process of the liquid nitrogen, a large amount of heat in the high-temperature gas is absorbed, so that the heat released by the gas discharged from the quenching furnace 1 can be fully utilized, reducing energy waste;

[0038] 2) Nitrogen recovery: After the high-temperature gas passes through the vaporizer 3, the electric flow valve 36 and the first air pump 37 are opened. The first air pump 37 can transport the high-temperature gas inside the vaporizer 3 to the filter 12. The filter 12 filters out the particulate impurities in the gas. The filtered gas first passes through the heat exchanger 14. The heat exchanger 14 performs heat exchange and cooling on the gas, which can reduce the cooling pressure of the condenser 16. Then the gas undergoes a second heat exchange and cooling through the condenser 16, so that the gas is further condensed, and the nitrogen in the gas is condensed into liquid nitrogen. The condensed liquid nitrogen and the uncondensed gas flow to the connector 434 through the ninth connecting pipe 17, and are sprayed out from the spray hole 435 of the arc-shaped spray pipe 431 through the diverter pipe 433. Under the action of gravity, most of the condensed liquid nitrogen flows into the bottom of the gas-liquid separation tank 10, and part of the liquid nitrogen is mixed in the uncondensed gas. The condensed liquid nitrogen and the uncondensed gas are preliminarily separated. As the liquid nitrogen flows into the gas-liquid separation tank 10, the liquid level gradually rises. , the floating ball 442 floats up and drives the guide block 444 to move upward along the guide rod 445, and the conical piston 443 also moves upward, and the conical piston 443 is separated from the liquid outlet 447, and the liquid nitrogen in the gas-liquid separation tank 10 that is higher than the drainage port 447 is discharged through the drainage pipe 441. At this time, the liquid level sensor 448 in the gas-liquid separation tank 10 detects the liquid nitrogen level and feeds back to the PLC controller. The PLC controller controls the second low-temperature circulation pump 447 to start pumping liquid, and the liquid nitrogen in the gas-liquid separation tank 10 is pumped out. The liquid nitrogen is added to the liquid nitrogen storage tank 8 through the fifth connecting pipe 9. As the liquid level inside the gas-liquid separation tank 10 drops, the floating ball 442 also drops. When the liquid nitrogen in the gas-liquid separation tank 10 is about to be pumped out, the floating ball 442 can drop to the inside of the drainage port 447 to block the drainage port 447. The liquid level sensor 448 detects the liquid nitrogen level and feeds back to the PLC controller, and the second low-temperature circulation pump 447 of the PLC controller stops working;

[0039] 3) Gas-liquid separation: The uncondensed gas passes through the filter 51 at the lower end of the frame 48. The filter 51 can block some liquid droplets in the uncondensed gas and perform preliminary separation on the uncondensed gas. The separated liquid droplets are discharged along the filter 51. The gas continues to move upward along the gas channel 50 with the unseparated liquid droplets. When the gas passes through the bend of the baffle 49, the moving direction will change. The liquid droplets with larger inertia force in the gas will hit the bend 492. The liquid collecting block 493 on the bend 492 can make the liquid part attached to the bend 492 flow along the bend 492. The liquid collecting block 493 moves downward to further separate the uncondensed gas, and the gas entrains and the unseparated liquid droplets and continues to move upward into the fixed ring 52. The swirl plate 54 can make the gas-liquid mixed airflow form a strong swirling airflow in the fixed ring 52, which is conducive to the liquid phase in the mixed airflow adhering to the surface under the action of centrifugal force and inertial force. At the same time, a plurality of guide holes 55 are evenly opened on the edge of the swirl plate 54, which can ensure that the liquid separated from the top of the gas-liquid separation tank 10 flows down quickly along the inner wall of the gas-liquid separation tank 10, thereby improving the gas-liquid separation effect;

[0040] 4) Vaporization of liquid nitrogen: the first low-temperature circulation pump 42 starts to work, and the liquid nitrogen in the liquid nitrogen storage tank 8 can be transported to the vaporizer 3 through the fourth connecting pipe 7. The liquid nitrogen is heated by the high-temperature gas in the heat exchange tube 33, so that the liquid nitrogen in the vaporizer 3 is heated and vaporized. In the process of vaporization of liquid nitrogen, nitrogen and dense fog are generated. The nitrogen and dense fog flow upward along the heat exchange tube 33, the spiral heat-conducting fins 38 and the spiral channel to form a vortex. In the process of flowing, the dense fog hits the heat exchange tube 33 and the spiral heat-conducting fins 38 to form droplets. The nitrogen continues to flow upward along the spiral channel. Under the action of gravity, the droplets flow along the heat exchange tube 33 and the spiral heat-conducting fins 38, and flow to the bottom of the vaporizer 3, and are vaporized twice through the heat exchange tube 33, so that the liquid nitrogen is vaporized more thoroughly, and the vaporization effect of the liquid nitrogen is improved;

[0041] 5) Workpiece quenching: The electric flow valve 31 and the first air pump 32 start working. At this time, the nitrogen in the nitrogen storage tank 5 enters the quenching furnace 1 through the second connecting pipe 4, and the nitrogen flows into the first diversion channel 24 and the second diversion channel 26 through a plurality of drainage pipes 27 respectively. The nitrogen in the first diversion channel 24 enters the drainage tube 22 through a plurality of first diversion holes 28, so that the nitrogen is evenly diffused and diverted in the drainage tube 22. At the same time, the nitrogen in the second diversion channel 26 enters the drainage tube 22 through a plurality of second diversion holes 29, so that the nitrogen is evenly diffused and diverted in the drainage tube 22, thereby effectively improving the uniformity of the nitrogen in the quenching furnace, thereby improving the quenching effect of the metal workpiece.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatically controlled nitrogen saving device, characterized in that: The invention comprises a quenching furnace (1), a vaporizer (3), a liquid nitrogen storage tank (5), a nitrogen storage tank (8), a gas-liquid separation tank (10), a filter (12), a heat exchanger (14) and a condenser (16); the exhaust port of the quenching furnace (1) is connected to the medium inlet of the vaporizer (3) through a first connecting pipe (2); the air inlet of the quenching furnace (1) is connected to the nitrogen storage tank (5) through a second connecting pipe (4); the nitrogen storage tank (5) is connected to the vaporizer (3) through a third connecting pipe (6); the vaporizer (3) is connected to the liquid nitrogen storage tank (8) through a fourth connecting pipe (7); the liquid nitrogen storage tank ( 8) is connected to the liquid phase outlet of the gas-liquid separation tank (10) through the fifth connecting pipe (9), the medium outlet of the vaporizer (3) is connected to the filter (12) through the sixth connecting pipe (11), the filter (12) is connected to the heat exchanger (14) through the seventh connecting pipe (13), the heat exchanger (14) is connected to the condenser (16) through the eighth connecting pipe (15), the condenser (16) is connected to the gas phase outlet of the gas-liquid separation tank (10) through the ninth connecting pipe (17), and the liquid phase inlet of the gas-liquid separation tank (10) is connected to the eighth connecting pipe (15) through the tenth connecting pipe (18).

2. The automatic controlled nitrogen saving device according to claim 1, characterized in that: One end of the quenching furnace (1) is rotatably connected to a sealing door (19); a temperature sensor (20) and a nitrogen concentration sensor (21) are installed inside the quenching furnace (1); a drainage tube (22) is also installed inside the quenching furnace (1); a placement rack (23) is installed inside the drainage tube (22); a first shunt channel (24) is provided between the drainage tube (22) and the quenching furnace (1); a drainage block (25) is installed at one end of the drainage tube (22); a second shunt channel (26) is provided between the drainage block (25) and the drainage tube (22); and a plurality of drainage tubes (27) connected to the second connecting tube (4) are provided inside the drainage block (25).

3. The automatic controlled nitrogen saving device according to claim 1, characterized in that: An electric flow valve (31) is installed on the second connecting pipe (4), and a first air pump (32) is connected to the second connecting pipe (4). The left end of the drainage tube (22) is a closed end wall, and the right end of the drainage tube (22) is a tube mouth. The upper and lower ends of the drainage tube (22) are annular end walls. A plurality of first diversion holes (28) are distributed at intervals on the annular end wall of the drainage tube (22). A plurality of second diversion holes (29) are distributed at intervals on the left end wall of the drainage tube (22). The plurality of second diversion holes (29) are connected to the second diversion channel (26), and a plurality of heating tubes (30) are evenly installed on the inner wall of the drainage tube (22).

4. The automatic controlled nitrogen saving device according to claim 1, characterized in that: The vaporizer (3) is provided with an S-shaped heat exchange tube (33) inside. One end of the heat exchange tube (33) is connected to the first connecting tube (2). The first connecting tube (2) is provided with a first one-way valve (34). The first connecting tube (2) is connected to a second air pump (35). The other end of the heat exchange tube (33) is connected to the sixth connecting tube (11). The sixth connecting tube (11) is provided with a second one-way valve (36). The sixth connecting tube (11) is connected to a third air pump (37). A spiral heat-conducting fin (38) is formed around the heat exchange tube (33) and is wound around the heat exchange tube (33). A spiral channel is formed between the heat-conducting fin (38) and the heat exchange tube (33). A pressure gauge is installed on the top of the vaporizer (3).

5. The automatic controlled nitrogen saving device according to claim 4, characterized in that: The vaporizer (3) is connected to a third connecting pipe (6), a third one-way valve (39) is installed on the third connecting pipe (6), a fourth air pump (40) is connected to the third connecting pipe (6), the vaporizer (3) is also connected to a fourth connecting pipe (7), a fourth one-way valve (41) is installed on the fourth connecting pipe (7), and a first low-temperature circulation pump (42) is connected to the fourth connecting pipe (7).

6. The automatic controlled nitrogen saving device according to claim 1, characterized in that: An annular spray rack (43) is arranged inside the gas-liquid separation tank (10), and the annular spray rack (43) includes four arc-shaped spray pipes (431) and a three-way joint (432) for connecting adjacent arc-shaped spray pipes (431). The arc-shaped spray pipe (431) is connected to a branch pipe (433) through the three-way joint (432), and the branch pipe (433) is connected to the second connecting pipe (17) through a connector (434). A plurality of spray holes (435) with openings facing downward are provided along the length direction of the arc-shaped spray pipe (431).

7. The automatic controlled nitrogen saving device according to claim 6, characterized in that: A liquid discharge assembly (44) is arranged below the annular spray rack (43). The liquid discharge assembly (44) comprises a liquid discharge switch and a liquid discharge pipe (441). The liquid level switch is used to control the on and off of the liquid discharge pipe (441) according to the liquid level height of the liquid in the gas-liquid separation tank (10). The liquid level switch comprises a floating ball (442). A conical piston (443) is installed at the bottom of the floating ball (442). Guide blocks (444) are installed on both sides of the floating ball (442). The guide blocks (444) are slidably arranged on the guide rod (445). A limit baffle (446) is installed at the top of the guide rod (445).

8. The automatic controlled nitrogen saving device according to claim 7, characterized in that: A liquid discharge port is provided below the conical piston (443), and the liquid discharge port is provided in the middle of the bottom end of the gas-liquid separation tank (10). A liquid discharge pipe (441) connected to the liquid discharge port is provided on the gas-liquid separation tank (10), and the liquid discharge pipe (441) is connected to the fifth connecting pipe (9). A second low-temperature circulation pump (447) is connected to the liquid discharge pipe (441). An exhaust pipe (45) is provided on the top of the gas-liquid separation tank (10), and the exhaust pipe (45) is connected to the condenser (16). A fifth one-way valve (46) is installed on the exhaust pipe (45), and a fifth air pump (47) is connected to the exhaust pipe (45).

9. The automatic controlled nitrogen saving device according to claim 8, characterized in that: A frame (48) is arranged above the annular spray frame (43), a cavity is arranged in the middle of the frame (48), a plurality of baffles (49) are arranged in the cavity, the baffles (49) include a vertical portion (491) and a bent portion (492) connected in sequence, the baffles (49) are in a trapezoidal structure, a gas channel (50) is formed between every two adjacent baffles (49), a plurality of liquid collecting blocks (493) are arranged on the bent portion (462) at the upper and lower ends of each gas channel (50), and the plurality of liquid collecting blocks (493) are evenly spaced on the bent portion (492).

10. The automatic controlled nitrogen saving device according to claim 9, characterized in that: A filter screen (51) is arranged at the bottom of the frame (48), a fixing ring (52) is arranged above the frame (48), a fixing column (53) is arranged in the middle of the fixing ring (52), a plurality of swirl plates (54) are arranged between the fixing column (53) and the fixing ring (52), and a plurality of guide holes (55) are evenly arranged on the edge of the fixing ring (52).

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