CN214173000U - Environment-friendly vacuum closed nitriding furnace - Google Patents

Abstract

The utility model relates to an airtight nitriding furnace in environment-friendly vacuum, including the vacuum pump, the ammonia source, exhaust gas purification case, outer stove and interior stove, outer stove is from inside to outside including interior heat preservation, the insulating layer, outer heat preservation and outer inoxidizing coating, it is equipped with intake pipe and stirring main shaft to rotate in the interior stove, intake pipe bottom both sides intercommunication has L shape bronchus, the vertical portion of bronchus has a plurality of shower nozzles down and its inboard distribution, the intake pipe top is stretched out interior stove and is connected with transmission, the intake pipe top is rotated and is connected with the sealed suction hood with ammonia source intercommunication, stirring main shaft upper portion is equipped with a plurality of main stirring rakes of group and cross support, it is equipped with the stirring son axle all to rotate on the cross support tip, be equipped with a plurality of groups stirring rake on the stirring son, vacuum pump and exhaust gas purification case and interior stove top intercommunication. The utility model discloses can effectively stir material and ammonia and distribute gas, effectively purify and absorb and strengthen thermal-insulated thermal insulation performance to waste gas, environmental protection more improves chromium nitride and prepares efficiency and quality.

Description

Environment-friendly vacuum closed nitriding furnace

Technical Field

The utility model belongs to the technical field of the chromium nitride production, concretely relates to airtight nitriding furnace in environment-friendly vacuum.

Background

Chromium nitride is a diluted magnetic semiconductor material with oxidation resistance, corrosion resistance, high hardness, high temperature resistance and better thermal conductivity, can be used for manufacturing cutters, stamping and drawing dies, powder forming dies, die casting dies and the like, has excellent compression resistance, scratch resistance and mirror surface property, can also be used as coatings, additives and film materials to be widely applied to modern industry and process production, and is an indispensable material for modern technical production.

At present, the preparation of chromium nitride mainly comprises a high-energy ball milling method, a benzene thermal method, a high-temperature self-propagating method, an ammonolysis method and the like. The ammonolysis process is a process for producing chromium nitride by using ammonia gas as a catalyst and directly reacting the ammonia gas with metal chromium or chromium halide at a high temperature, and common process equipment comprises a roasting furnace, a tubular furnace, a nitriding furnace and the like. The nitriding furnace is equipment with nitriding treatment, has the characteristics of low treatment temperature, short time, small workpiece deformation and the like, and has high fatigue limit and good wear resistance. However, the conventional nitriding furnace still has the following problems in practical use: 1. the lack of a certain material stirring mechanism and a certain gas distribution mechanism in the furnace leads to poor material uniformity and poor ammonia gas fluidity and uniformity in the nitriding process, so that the reaction effect of the materials and the ammonia gas is poor, the reaction efficiency and the quality are low, and the efficient and high-quality preparation of chromium nitride is not facilitated; 2. the heat insulation performance of the furnace body is poor, heat loss is serious in the nitriding process, higher energy consumption is needed for heating and warming, and the cost is higher; 3. according to the difference of the used production raw materials, mixed waste gas containing nitrogen, hydrogen, ammonia and the like can be generated in the nitriding process, and the direct discharge can cause serious pollution to the environment, is not favorable for environmental protection and needs to be improved.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model aims at providing an airtight nitriding furnace in environment-friendly vacuum can carry out effective and even stirring and gas distribution to material and ammonia, can strengthen whole nitriding furnace's thermal-insulated heat preservation performance greatly to can effectively purify and absorb waste gas, in order to solve above-mentioned problem.

In order to achieve the above object, the utility model adopts the following technical scheme: an environment-friendly vacuum closed nitriding furnace comprises a vacuum pump, an ammonia source, a waste gas purification box, an outer furnace and an inner furnace embedded in the outer furnace, wherein the outer furnace sequentially comprises an inner heat-insulating layer, a heat-insulating layer, an outer heat-insulating layer and an outer protective layer from inside to outside; the top of the inner furnace is provided with a feeding pipe, the outer side wall of the inner furnace is fixedly sleeved with an annular electric heater, the bottom of the inner furnace is provided with a discharging pipe extending out of the outer furnace, and the feeding pipe and the discharging pipe are both provided with valves; an air inlet pipe is vertically and rotatably arranged in the upper part of the inner furnace, a stirring main shaft is vertically and rotatably arranged in the lower part of the inner furnace, the bottom end of the air inlet pipe is closed, two sides of the end of the air inlet pipe are communicated with L-shaped branch air pipes, the vertical part of each branch air pipe is arranged close to the inner side wall of the inner furnace downwards, a plurality of spray heads are vertically distributed on the inner side of each branch air pipe at intervals, the top of each air inlet pipe extends out of the inner furnace and is connected with a transmission device, the top end of each air inlet pipe is opened and is rotatably connected with a sealed air inlet hood, the sealed air inlet hood is communicated with an ammonia gas source, a plurality of groups of main stirring paddles are vertically arranged on the upper part of the stirring main shaft at intervals, a cross-shaped support is fixedly sleeved on the lower part of the upper part of the stirring main stirring shaft, stirring sub-shafts are vertically and rotatably arranged on the four end parts of the cross-shaped support, and a plurality of groups of sub stirring paddles are vertically arranged on the stirring shafts at intervals, and are distributed with the main stirring paddles in a staggered manner; the vacuum pump is communicated with the top of the inner furnace through a vacuum pipe; waste gas purification case includes the box, box one side lower part has been seted up the air inlet, opposite side upper portion has been seted up the gas vent, the air inlet is through arranging waste pipe and interior stove top intercommunication, be equipped with first filter screen, second filter screen, active carbon adsorption layer and anti-permeation layer by air inlet to gas vent direction interval in proper order in the box.

Preferably, the inner heat-insulating layer and the outer heat-insulating layer are both built by high-alumina light heat-insulating bricks, the heat-insulating layer is made of an aluminum silicate fiberboard, and the outer protective layer is made of a steel plate.

Preferably, transmission is including locating the transmission case on the outer top of interior stove, the intake pipe top stretches into in the transmission case and fixed cover is equipped with driven gear in the intake pipe of this part, the top has set firmly first motor in the transmission case of intake pipe one side, the output shaft of first motor is down and fixed cover is equipped with the driving gear, the driving gear is connected with driven gear meshing.

Preferably, the sealed air inlet hood is fixedly arranged on the inner top of the transmission box corresponding to the air inlet pipe, the bottom end of the sealed air inlet hood is rotatably communicated with the top end of the air inlet pipe, and the top end of the sealed air inlet hood is communicated with an ammonia gas source through an ammonia gas conveying pipe with a pressure stabilizing valve.

Preferably, the stirring main shaft is opposite with the coaxial setting of intake pipe and rotation direction between them, the stirring main shaft bottom is stretched out outer stove and the transmission is connected with the second motor, main stirring rake on the stirring main shaft is radially set up and is the main puddler of circumference interval equipartition by four and forms, and four main puddlers set up towards four tip place directions of cross support respectively.

Preferably, the stirring shaft bottom runs through the cross support and the transmission is connected with the third motor, the outside guard box that all covers of third motor and second motor, the epaxial sub-stirring rake of stirring comprises two radial and symmetric distribution's sub-puddler.

Preferably, the mesh aperture of the first screen is larger than the mesh aperture of the second screen.

Preferably, the cooling water system further comprises a cooling water tank and an air cooler, a gap is formed between the inner side wall of the inner heat insulation layer of the outer furnace and the outer side wall of the inner furnace, a water cooling mechanism and an air cooling mechanism are arranged in the gap, the water cooling mechanism comprises a plurality of circles of cooling water pipes wound on the outer side of the inner furnace, the bottoms of the cooling water pipes are communicated with the water outlet of the cooling water tank through a water inlet pipe with a water inlet pump, and the tops of the cooling water pipes are communicated with the water inlet of the cooling water tank through a water outlet pipe with a water outlet pump; the air cooling mechanism comprises an air inlet pipe communicated with the bottom of one side of the outer furnace and an exhaust pipe communicated with the top of the other side of the outer furnace, an air inlet fan is arranged in one end, extending into the outer furnace, of the air inlet pipe, the other end of the air inlet pipe is communicated with an air outlet of the air cooler, and an exhaust fan is arranged in the exhaust pipe.

Preferably, the system also comprises an infrared thermometer arranged on the top outside the inner furnace and a control center arranged on the outer side wall of the outer furnace, wherein a detection probe of the infrared thermometer extends into the inner furnace, and the infrared thermometer, the annular electric heater, the air cooler, the air inlet fan and the exhaust fan, the water inlet pump and the water outlet pump are all electrically connected with the control center.

The utility model has the advantages that: the utility model relates to a rationally, compact structure, main puddler on the main shaft of stirring and the setting cooperation of stirring sub-axis and the sub-puddler on it, can stir the material at the nitrogenize in-process, and during the stirring, the epaxial sub-puddler of stirring can carry out the revolution along with main puddler on the main shaft of stirring and, can carry out the rotation under the drive of corresponding stirring sub-axis again, add the crisscross distribution of main puddler and sub-puddler, alright strengthen stirring effect greatly, make and mix between the material more evenly, completely, improve stirring efficiency and quality greatly. Meanwhile, the ammonia source, the sealed air inlet cover, the rotating air inlet pipe, the bronchus and the spray heads on the bronchus are matched, the required ammonia can be sprayed out of the inner furnace while stirring, the output of the ammonia generates dynamic change along with the rotation motion of the bronchus, so that the fluidity and the uniformity of the ammonia can be greatly enhanced, the reaction effect of materials and the ammonia can be greatly enhanced, the reaction efficiency and the quality are improved, and the high-efficiency and high-quality preparation of chromium nitride is more facilitated. In addition, the material can be stirred by the rotation of the branch gas pipe, and the rotation direction of the branch gas pipe is opposite to that of the stirring main shaft, so that the stirring effect on the material can be further enhanced, the stirring dead angle is avoided, the full contact reaction of ammonia gas and the material is ensured, and the preparation of chromium nitride is ensured.

The setting of the outer furnace consisting of the inner heat-insulating layer, the outer heat-insulating layer and the outer protective layer can realize one-time heat-insulating protection, two-time heat-insulating protection and outmost strength protection of the inner furnace, thereby greatly improving the heat-insulating performance of the whole nitriding furnace, effectively reducing the heat loss in the nitriding process, being more beneficial to ensuring the stability of the appropriate temperature required by nitriding, reducing the energy consumption, saving the production cost and improving the economic benefit of enterprises.

First filter screen, second filter screen, active carbon adsorption layer and the cooperation of setting of reverse osmosis layer in the exhaust gas purification case can be successively carry out two-stage filtration edulcoration, active carbon adsorption purification and final reverse osmosis absorption purification to nitriding process from interior stove exhaust waste gas, guarantee the cleanness of exhaust tail gas, avoid environmental pollution, more be favorable to the environmental protection and maintain that the workman is healthy.

Drawings

Fig. 1 is a schematic structural diagram of the present invention;

FIG. 2 is a schematic structural view of the exhaust gas purifying box of the present invention;

fig. 3 is a schematic top view of the cross-shaped bracket of the present invention.

Reference numbers in the figures: 1 is an outer furnace, 2 is an outer protective layer, 3 is an outer insulating layer, 4 is an insulating layer, 5 is an inner insulating layer, 6 is an inner furnace, 7 is a feeding pipe, 8 is an annular electric heater, 9 is a discharging pipe, 10 is a valve, 11 is an air inlet pipe, 12 is a branch pipe, 13 is a spray head, 14 is a transmission box, 15 is a first motor, 16 is a driving gear, 17 is a driven gear, 18 is a sealed air inlet hood, 19 is an ammonia gas conveying pipe, 20 is a pressure stabilizing valve, 21 is an ammonia gas source, 22 is a stirring main shaft, 23 is a main stirring rod, 24 is a stirring sub-shaft, 25 is a stirring sub-rod, 26 is a cross-shaped bracket, 27 is a second motor, 28 is a third motor, 29 is a protective box, 30 is a waste discharging pipe, 31 is a waste gas purifying box, 32 is a vacuum pipe, 33 is a vacuum pump, 34 is a cooling water pipe, 35 is a water inlet pipe, 36 is a water inlet pump, 37 is a cooling water tank, 38 is a water outlet pump, 39 is a water outlet pipe, and 40 is a cold air blower, 41 is an air inlet fan, 42 is an air inlet pipe, 43 is an exhaust pipe, 44 is an exhaust fan, 45 is an infrared thermometer, 46 is a control center, 47 is a box body, 48 is an air inlet, 49 is an exhaust port, 50 is a first filter screen, 51 is a second filter screen, 52 is an activated carbon adsorption layer, and 53 is a reverse osmosis layer.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments:

as shown in fig. 1 to 3, an environmentally friendly vacuum-tight nitriding furnace includes a vacuum pump 33, an ammonia source 21, a waste gas purifying tank 31, an outer furnace 1, and an inner furnace 6 embedded in the outer furnace 1. The outer furnace 1 sequentially comprises an inner heat-insulating layer 5, a heat-insulating layer 4, an outer heat-insulating layer 3 and an outer protective layer 2 from inside to outside, and can realize one-time heat-insulating protection, two-time heat-insulating protection and outermost layer strength protection on the inner furnace 6, so that the heat-insulating and heat-insulating performance of the whole nitriding furnace can be greatly improved, heat loss in the nitriding process can be effectively reduced, the stability of proper temperature required by nitriding can be ensured, the energy consumption is reduced, the production cost is saved, and the economic benefit of enterprises is improved;

the top of interior stove 6 is equipped with inlet pipe 7, the bottom is equipped with the discharging pipe 9 that stretches out outer stove 1, all is equipped with valve 10 on inlet pipe 7 and the discharging pipe 9, is used for the feeding respectively and the ejection of compact. The fixed cover of lateral wall of interior stove 6 is equipped with annular electric heater 8 for carrying out even electrical heating intensification to interior stove 6, provide the required temperature condition of chromium nitride preparation, and it belongs to prior art, and no longer detailed here. An air inlet pipe 11 is vertically and rotatably arranged in the upper part of the inner furnace 6, and a stirring main shaft 22 is vertically and rotatably arranged in the lower part of the inner furnace and is used for air inlet and stirring respectively. The bottom end of the air inlet pipe 11 is closed, two sides of the end are communicated with L-shaped branch air pipes 12, the vertical parts of the branch air pipes 12 are arranged downwards close to the inner side wall of the inner furnace 6, and a plurality of spray heads 13 are vertically distributed on the inner side of the branch air pipes at intervals. The top of the air inlet pipe 11 extends out of the inner furnace 6 and is connected with a transmission device, the top end of the air inlet pipe 11 is opened and is rotatably connected with a sealed air inlet cover 18, and the sealed air inlet cover 18 is communicated with an ammonia source 21. The upper part of the stirring main shaft 22 is provided with a plurality of groups of main stirring paddles at intervals up and down, and the lower part is fixedly sleeved with a cross-shaped bracket 26. All vertically just rotate on four tip of cross support 26 and be equipped with stirring sub-axle 24, be on the stirring sub-axle 24 and be equipped with a plurality of groups sub-stirring rake about the interval, sub-stirring rake and main stirring rake crisscross distribution. During the use, the main stirring rake on the stirring main shaft 22 and the setting cooperation of main stirring rake and stirring sub-axle 24 and the sub-stirring rake on it can stir the material at the nitridation in-process, and sub-stirring rake can carry out the revolution along with stirring main shaft 22 and the main stirring rake on it, can carry out the rotation under corresponding stirring sub-axle 24's drive again, and its crisscross distribution with main stirring rake in addition, alright strengthen stirring effect greatly, make and mix between the material more evenly, completely, improve stirring efficiency and quality greatly. Meanwhile, the ammonia source 21, the sealed air inlet cover 18, the rotating air inlet pipe 11, the bronchus 12 and the upper spray head 13 are matched, so that the required ammonia can be sprayed into the inner furnace 6 while stirring, the output of the ammonia is dynamically changed along with the rotation of the bronchus 12, the fluidity and the uniformity of the ammonia can be greatly enhanced, the reaction effect of materials and the ammonia can be greatly enhanced, the reaction efficiency and the quality are improved, and the efficient and high-quality preparation of chromium nitride is facilitated;

the vacuum pump 33 is communicated with the top of the inner furnace 6 through the vacuum pipe 32, so that before nitriding, the inner furnace 6 can be vacuumized through the vacuum pump 33, ammonia gas is conveyed into the inner furnace 6 through the ammonia gas source 21, the required ammonia gas environment for preparing chromium nitride is ensured, and the preparation quality of chromium nitride is improved. The exhaust gas purifying box 31 includes a box body 47, and an air inlet 48 is opened at a lower portion of one side of the box body 47 and an air outlet 49 is opened at an upper portion of the other side. The gas inlet 48 communicates with the top of the inner furnace 6 through the waste pipe 30. Be equipped with first filter screen 50 by air inlet 48 to 49 direction intervals in proper order of gas vent in the box 47, second filter screen 51, activated carbon adsorption layer 52 and reverse osmosis layer 53, first filter screen 50's mesh aperture is greater than second filter screen 51's mesh aperture, make when using, through first filter screen 50, second filter screen 51, activated carbon adsorption layer 52 and reverse osmosis layer 53 set up the cooperation, can successively carry out the two-stage to nitriding in-process from the exhaust gas of interior stove 6 edulcoration, activated carbon adsorption purifies and final reverse osmosis absorption purifies, guarantee the clean of exhaust tail gas, avoid environmental pollution, more be favorable to the environmental protection and maintain that the workman is healthy.

In the embodiment, the inner insulating layer 5 and the outer insulating layer 3 are both built by high-alumina light insulating bricks, and have the characteristics of high compressive strength, low heat conductivity coefficient, good insulating property, low price and the like. The heat insulation layer 4 is made of an aluminum silicate fiberboard and has the advantages of light volume weight, high temperature resistance, good thermal stability, low thermal conductivity, small thermal capacity, good mechanical vibration resistance, small thermal expansion, good heat insulation performance and the like. The outer protective layer 2 is made of a steel plate to further reinforce the strength of the whole nitriding furnace.

In this embodiment, the transmission device comprises a transmission box 14 arranged on the outer top of the inner furnace 6, the top of the air inlet pipe 11 extends into the transmission box 14, and a driven gear 17 is fixedly sleeved on the air inlet pipe 11 of the part. The interior top of the transmission case 14 of intake pipe 11 one side has set firmly first motor 15, and the output shaft of first motor 15 is equipped with driving gear 16 down and fixed cover, and driving gear 16 is connected with driven gear 17 meshing for when using, provide power through first motor 15, alright drive driving gear 16 and rotate, through driving gear 16 and driven gear 17's meshing transmission, alright drive driven gear 17 and intake pipe 11 rotate, thereby the cooperation realizes the operation of dynamic admitting air. The sealed air inlet hood 18 is fixedly arranged on the inner top of the transmission box 14 corresponding to the air inlet pipe 11, the bottom end of the sealed air inlet hood 18 is rotatably communicated with the top end of the air inlet pipe 11, the top end of the sealed air inlet hood 18 is communicated with an ammonia source 21 through an ammonia conveying pipe 19 with a pressure stabilizing valve 20, so that when chromium nitride is prepared through nitridation, ammonia in the ammonia source 21 can be pumped into the sealed air inlet hood 18 through the ammonia conveying pipe 19 only by opening the pressure stabilizing valve 20, the ammonia is further conveyed into the air inlet pipe 11 through the sealed air inlet hood 18 under the condition that the rotation of the air inlet pipe 11 is not influenced, the ammonia is then shunted into the two air inlet pipes 12, and finally the ammonia is sprayed out through the spray head 13 to complete dynamic air inlet operation in a matching manner.

In this embodiment, stirring main shaft 22 and the coaxial setting of intake pipe 11 and rotation opposite direction between them for when using, bronchus 12's rotation can stir the material equally, and its rotation opposite direction with stirring main shaft 22 can further strengthen the stirring effect to the material, avoids stirring the dead angle, guarantees ammonia and the abundant contact reaction of material, guarantees the preparation of chromium nitride. The bottom of main mixing shaft 22 stretches out outer stove 1 and the transmission is connected with second motor 27, main puddler on the main mixing shaft 22 is radially set up and is the main puddler 23 of circumference interval equipartition by four and forms, and four main puddlers 23 set up towards four tip directions of cruciform support 26 respectively, make when using, utilize second motor 27 to provide power, alright drive main mixing shaft 22 and main puddler 23 and the stirring son axle 4 on it revolute, the cooperation realizes the stirring to the material. The bottom end of the stirring sub-shaft 24 penetrates through the cross-shaped support 26 and is connected with a third motor 28 in a transmission mode, the sub-stirring paddles on the stirring sub-shaft 24 are composed of two radial and symmetrically distributed sub-stirring rods 25, and therefore when the stirring sub-shaft is used, the third motor 28 is used for providing power, the corresponding stirring sub-shaft 24 and the sub-stirring rods 25 on the stirring sub-shaft can be driven to rotate, and stirring efficiency and quality are further improved. The third motor 28 and the second motor 27 are each externally covered with a protective box 29 for protecting the respective motors.

In the present embodiment, a cooling water tank 37 and an air cooler 40 are further included. There is the clearance between the inside wall of the interior heat preservation 5 of outer stove 1 and the lateral wall of interior stove 6, is equipped with water-cooling mechanism and forced air cooling mechanism in this clearance for carry out water-cooling and forced air cooling to interior stove 6. The water cooling mechanism comprises a plurality of circles of cooling water pipes 34 wound on the outer side of the inner furnace 6, the bottoms of the cooling water pipes 34 are communicated with the water outlet of the cooling water tank 37 through water inlet pipes 35 with water inlet pumps 36, and the tops of the cooling water pipes 34 are communicated with the water inlet of the cooling water tank 37 through water outlet pipes 39 with water outlet pumps 38, so that when water cooling is carried out, the cooling water in the cooling water tank 37 can be pumped into the cooling water pipes 34 through the water inlet pipes 35 by the water inlet pumps 36, and the inner furnace 6 is cooled by the water. The cooling water after the superheat exchange is collected in the water outlet pipe 39, and can flow back to the cooling water tank 37 again for recycling under the suction force of the water outlet pump 38, so that the waste of water resources can be greatly reduced, the water resources can be saved, the production cost can be reduced, and the enterprise benefit can be improved. The cooling water tank 37 adopts a conventional integrated cooling water tank in the prior art, the cooling water tank is an existing advanced circulating water cooling device, can be widely applied to matching of other electrical appliances and mechanical equipment which need circulating water cooling, and the like, a water circulating radiator, a cooling fan, a water path circulating system, a water level indicating device and other parts are integrated in the cooling water tank, when in use, the cooling operation of cooling water on the equipment and the backflow cyclic utilization of the cooling water can be realized by matching with a circulating water pump, the cooling water tank is convenient to use, and does not waste water resources, the specific structure and the working principle of the cooling water tank belong to the prior art, and are not explained herein;

the forced air cooling mechanism is including the air-supply line 42 and the exhaust pipe 43 of intercommunication at outer stove 1 opposite side top of intercommunication in outer stove 1 one side bottom of intercommunication, air-supply line 42 stretches into and is equipped with air inlet fan 41 in the one end of outer stove 1, the other end communicates with the air outlet of air-cooler 40, be equipped with air discharge fan 44 in the exhaust pipe 43, make when using, through air-cooler 40, air-supply line 42 and air inlet fan 41 in it, exhaust pipe 43 and the cooperation that sets up of air discharge fan 44 in it, can realize the cold air cooling to inner stove 6, combine water cooling mechanism alright realize the dual cooling to inner stove 6, the cooling rate is fast, the cooling is more even effective, can improve cooling efficiency and quality greatly, be more favorable to the rapid cooling of inner stove 6, be convenient for the quick ejection of compact of chromium nitride, do not influence the subsequent production and processing of chromium nitride, improve the holistic production efficiency of chromium nitride. The air cooler 40 adopts conventional industrial air coolers, and the industrial air cooler has the advantages of high efficiency, obvious cooling effect, energy conservation, environmental protection and the like, and ensures the sufficiency of required cold air.

In this embodiment, the furnace further comprises an infrared thermometer 45 disposed on the top of the inner furnace 6 and a control center 46 disposed on the outer sidewall of the outer furnace 6, and a detection probe of the infrared thermometer 45 extends into the inner furnace 6 to detect the temperature in the inner furnace 6 in real time. The infrared thermometer 45, the annular electric heater 8, the air cooler 40, the air inlet fan 41, the exhaust fan 44, the water inlet pump 36 and the water outlet pump 38 are all electrically connected with the control center 46, so that the automatic control of heating, cooling and cooling of the inner furnace 6 is realized in a matching manner, and the preparation efficiency and quality of chromium nitride can be better ensured. The control center 46 may be implemented using conventional PLC controllers.

The utility model discloses a theory of operation: when the utility model is used, the valve 10 on the feeding pipe 7 is firstly opened, and chromium powder or chromium halide materials are fed into the inner furnace 6 through the feeding pipe 7. After the feeding is completed, the valve 10 on the feeding pipe 7 is closed again, and the vacuum pump 33 is operated to evacuate the inner furnace 6. Then, the second motor 27 and the third motor 28 are operated, the second motor 27 can drive the stirring main shaft 22 and the main stirring rod 23 thereon, the stirring sub-shaft 24 and the sub-stirring rod 25 thereon to revolve, and the third motor 28 drives the corresponding stirring sub-shaft 24 and the sub-stirring rod 25 thereon to rotate, so as to realize efficient stirring of the materials. Meanwhile, the pressure stabilizing valve 20 is opened, the first motor 15 is operated, and dynamic air intake operation is performed through the cooperation of the ammonia gas delivery pipe 19, the sealed air intake cover 18, the air intake pipe 11 and the branch air pipe 12. In the process, the annular electric heater 8 works to heat the inner furnace 6. The infrared thermometer 45 detects the temperature of the inner chamber 6 in real time and transmits the temperature information to the control center 46. When the temperature rises to the set upper limit value, the control center 46 can automatically control the annular electric heater 8 to be closed and stop heating; when the temperature is lower than the set lower limit value, the control center 46 can automatically control the annular electric heater 8 to be turned on again to continue heating, so that the automatic control of heating and temperature rise is realized, the suitable temperature environment required by preparing the chromium nitride is ensured, and the efficient and high-quality preparation of the chromium nitride is realized by matching with stirring and gas transmission. The waste gas that produces in the preparation process then discharges to waste gas purification case 31 through arranging waste pipe 30 in, discharges after two-stage filtration edulcoration, active carbon adsorption purification and final reverse osmosis absorption purification, realizes the clean emission of waste gas, is favorable to the environmental protection.

After the reaction is finished, cooling the inner furnace 6, specifically: the water inlet pump 36 and the water outlet pump 38 are operated to pump the cooling water in the cooling water tank 37 into the cooling water pipe 34, and water-cool the inner furnace 6. The cooling water after being subjected to the superheat exchange is collected in the water outlet pipe 39, and flows back to the cooling water tank 37 again for recycling under the suction force of the water outlet pump 38, so that the water resource is saved. And during water cooling, the air cooler 40, the air inlet fan 41 and the exhaust fan 44 are operated, so that the air cooler 40 can produce cold air, and the cold air is pumped into the outer furnace 1 through the air inlet fan 41, thereby realizing cold air cooling of the inner furnace 6. The exhaust fan 44 can provide wind pumping force, and the air flow which is subjected to overheat exchange is discharged through the exhaust pipe 43, so that the heat is brought out in time while the stability of the air pressure in the outer furnace 1 is ensured, the cooling effect can be further enhanced, and the cooling efficiency and the quality are ensured. During the water cooling and the cold air cooling, the infrared thermometer 45 also detects the temperature of the inner furnace 6 in real time and transmits the information to the control center 46. When the temperature of the inner furnace 6 falls below the set value, the control center 46 may automatically control to stop the operation of the water inlet pump 36, the water outlet pump 38, the air inlet fan 41, the exhaust fan 44, and the cooling fan 40, thereby stopping the water cooling and the cooling of the cooling air. And finally, discharging through a discharging pipe 9.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims (9)

1. The environment-friendly vacuum closed nitriding furnace is characterized by comprising a vacuum pump, an ammonia source, a waste gas purification box, an outer furnace and an inner furnace embedded in the outer furnace, wherein the outer furnace sequentially comprises an inner heat-insulating layer, a heat-insulating layer, an outer heat-insulating layer and an outer protective layer from inside to outside; the top of the inner furnace is provided with a feeding pipe, the outer side wall of the inner furnace is fixedly sleeved with an annular electric heater, the bottom of the inner furnace is provided with a discharging pipe extending out of the outer furnace, and the feeding pipe and the discharging pipe are both provided with valves; an air inlet pipe is vertically and rotatably arranged in the upper part of the inner furnace, a stirring main shaft is vertically and rotatably arranged in the lower part of the inner furnace, the bottom end of the air inlet pipe is closed, two sides of the end of the air inlet pipe are communicated with L-shaped branch air pipes, the vertical part of each branch air pipe is arranged close to the inner side wall of the inner furnace downwards, a plurality of spray heads are vertically distributed on the inner side of each branch air pipe at intervals, the top of each air inlet pipe extends out of the inner furnace and is connected with a transmission device, the top end of each air inlet pipe is opened and is rotatably connected with a sealed air inlet hood, the sealed air inlet hood is communicated with an ammonia gas source, a plurality of groups of main stirring paddles are vertically arranged on the upper part of the stirring main shaft at intervals, a cross-shaped support is fixedly sleeved on the lower part of the upper part of the stirring main stirring shaft, stirring sub-shafts are vertically and rotatably arranged on the four end parts of the cross-shaped support, and a plurality of groups of sub stirring paddles are vertically arranged on the stirring shafts at intervals, and are distributed with the main stirring paddles in a staggered manner; the vacuum pump is communicated with the top of the inner furnace through a vacuum pipe; waste gas purification case includes the box, box one side lower part has been seted up the air inlet, opposite side upper portion has been seted up the gas vent, the air inlet is through arranging waste pipe and interior stove top intercommunication, be equipped with first filter screen, second filter screen, active carbon adsorption layer and anti-permeation layer by air inlet to gas vent direction interval in proper order in the box.

2. The environmentally friendly vacuum tight nitriding furnace according to claim 1, wherein the inner insulating layer and the outer insulating layer are both built by high alumina lightweight insulating bricks, the insulating layer is made of aluminum silicate fiber boards, and the outer protective layer is made of steel plates.

3. The environmentally friendly vacuum tight nitriding furnace according to claim 1, wherein the transmission device comprises a transmission box arranged on the top outside the inner furnace, the top of the air inlet pipe extends into the transmission box, a driven gear is fixedly sleeved on the air inlet pipe of the transmission box, a first motor is fixedly arranged on the top inside the transmission box on one side of the air inlet pipe, an output shaft of the first motor faces downwards, a driving gear is fixedly sleeved on the output shaft of the first motor, and the driving gear is meshed with the driven gear.

4. The environment-friendly vacuum closed nitriding furnace according to claim 3, wherein the sealed air inlet hood is fixedly arranged on the inner top of the transmission box corresponding to the air inlet pipe, the bottom end of the sealed air inlet hood is rotatably communicated with the top end of the air inlet pipe, and the top end of the sealed air inlet hood is communicated with an ammonia gas source through an ammonia gas conveying pipe with a pressure stabilizing valve.

5. The environmentally-friendly vacuum closed nitriding furnace according to claim 1, wherein the stirring main shaft is coaxially arranged with the air inlet pipe and the rotating directions of the stirring main shaft and the air inlet pipe are opposite, the bottom end of the stirring main shaft extends out of the outer furnace and is connected with a second motor in a transmission manner, main stirring paddles on the stirring main shaft are composed of four main stirring rods which are radially arranged and uniformly distributed at intervals on the circumference, and the four main stirring rods are respectively arranged towards the directions of the four end parts of the cross-shaped support.

6. The environmentally friendly vacuum closed nitriding furnace according to claim 5, wherein the bottom end of the stirring shaft penetrates through the cross-shaped bracket and is connected with a third motor in a transmission manner, the third motor and the second motor are both covered with a protective box, and the sub-stirring paddles on the stirring shaft are composed of two radially and symmetrically distributed sub-stirring rods.

7. The environmentally friendly vacuum tight nitriding furnace according to claim 1, wherein the first screen has a mesh opening size larger than that of the second screen.

8. The environment-friendly vacuum closed nitriding furnace according to claim 1, further comprising a cooling water tank and an air cooler, wherein a gap is formed between the inner side wall of the inner insulating layer of the outer furnace and the outer side wall of the inner furnace, a water cooling mechanism and an air cooling mechanism are arranged in the gap, the water cooling mechanism comprises a plurality of circles of cooling water pipes wound on the outer side of the inner furnace, the bottoms of the cooling water pipes are communicated with a water outlet of the cooling water tank through a water inlet pipe with a water inlet pump, and the tops of the cooling water pipes are communicated with a water inlet of the cooling water tank through a water outlet pipe with a water outlet pump; the air cooling mechanism comprises an air inlet pipe communicated with the bottom of one side of the outer furnace and an exhaust pipe communicated with the top of the other side of the outer furnace, an air inlet fan is arranged in one end, extending into the outer furnace, of the air inlet pipe, the other end of the air inlet pipe is communicated with an air outlet of the air cooler, and an exhaust fan is arranged in the exhaust pipe.

9. The environment-friendly vacuum closed nitriding furnace according to claim 8, further comprising an infrared thermometer arranged on the top outside the inner furnace and a control center arranged on the outer side wall of the outer furnace, wherein a detection probe of the infrared thermometer extends into the inner furnace, and the infrared thermometer, the annular electric heater, the air cooler, the air inlet fan and the exhaust fan, the water inlet pump and the water outlet pump are all electrically connected with the control center.

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