External circulation cooling well type vacuum high-pressure gas quenching furnace

Abstract

The utility model relates to the technical field of heat treatment equipment, in particular to a vacuum high-pressure gas quenching furnace which comprises a circulating fan. The gas circulating system comprises at least two gas conveying pipelines and a circulating fan for driving gas in the at least two gas conveying pipelines to circulate; the upper end and the lower end of the side face of the hearth are provided with at least two gas conveying openings. The gas conveying pipelines are communicated with the gas conveying openings in the upper end and the lower end of the hearth respectively. The gas circulation system further comprises an electric reversing valve. Two air source airflow ports of the electric reversing valve are communicated with an air inlet and an air outlet of the circulating fan respectively, and two air conveying pipelines are communicated with two air supply airflow ports of the electric reversing valve. The device further comprises a vacuumizing device. And the exhaust pipe of the vacuumizing device is communicated into the hearth, so that the direction of airflow in the furnace can be periodically switched, the uniformity of the temperature in the hearth is ensured, slender parts are uniformly cooled, and air is pumped out to improve the quenching quality of the parts.

Description

Technical Field

[0001] The present application relates to the technical field of heat treatment equipment, and in particular to a vacuum high-pressure gas quenching furnace. Background Art

[0002] The gas quenching process is a heat treatment method that quickly cools the parts by exposing them to a high-speed airflow. The vacuum high-pressure gas quenching furnace is a device used to quench materials, usually to increase the hardness and strength of the materials.

[0003] However, when a vacuum high-pressure gas quenching furnace is used to process slender parts, the furnace chamber of the gas quenching furnace required for quenching slender parts is also long, which is difficult to process using the horizontal installation method. In addition, the heat in the long furnace chamber is prone to uneven distribution, and the parts are prone to uneven cooling, resulting in problems such as reduced quality of heat treatment of parts or deformation of parts.

[0004] In order to improve the effect of heat treatment in the gas quenching furnace, the mixed air in the furnace needs to be extracted, and in order to ensure uniform cooling on the top and bottom sides of slender parts and reduce deformation, the direction of the airflow in the furnace needs to be switched periodically. Utility Model Content

[0005] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract of the specification and the name of the utility model of this application to avoid blurring the purpose of this section, the abstract of the specification and the name of the utility model, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0006] In view of the problems existing in the above-mentioned prior art, the present utility model is proposed.

[0007] An external circulation cooling well type vacuum high pressure gas quenching furnace comprises a furnace shell, a furnace chamber is arranged in the furnace shell, and a heating device is also arranged in the furnace chamber;

[0008] Also includes a gas circulation system;

[0009] The gas circulation system comprises at least two gas pipelines, and a circulation fan for driving gas circulation in the at least two gas pipelines;

[0010] At least two gas delivery ports are provided at the upper and lower ends of the furnace side, and the gas delivery pipeline is respectively connected to the gas delivery ports at the upper and lower ends of the furnace;

[0011] The circulating fan also includes an electric reversing valve;

[0012] Two air source flow ports are provided on the air source side of the electric reversing valve;

[0013] Two air supply ports are provided on the air supply side of the electric reversing valve;

[0014] The two air source air flow ports of the electric reversing valve are respectively connected to the air inlet and the air outlet of the circulating fan;

[0015] The two gas pipelines are respectively connected to the two gas supply ports of the electric reversing valve, so that the air inlet and the air outlet of the circulating fan are respectively connected to the two gas pipelines;

[0016] Also includes a vacuum device;

[0017] The vacuum pipe of the vacuum pumping device is connected to the furnace.

[0018] The above design, firstly, by setting up a gas circulation system, a water-cooling heat sink is provided in the gas circulation system, which can circulate cooled nitrogen into the furnace through two gas transmission pipelines, and at the same time transport the high-temperature nitrogen away and return it to the gas circulation system to be cooled again by the water-cooling heat sink, so that the heated parts can be quickly cooled by the circulating cooled nitrogen, and the quenching of the parts can be completed quickly; secondly, by setting up an electric reversing valve, the flow direction of the circulating nitrogen in the furnace is reversed once every 6-12 seconds (from top to bottom to bottom to top, or from bottom to top to top to bottom), so that the direction of the airflow in the furnace can be switched periodically, thereby improving the uniformity of the temperature in the furnace, ensuring uniform cooling of slender parts, reducing deformation, and improving the quality of part quenching; finally, by setting up a vacuum pumping device, the air in the furnace is extracted and then the parts are heated to prevent the air from volatilizing the alloy elements of the parts, thereby improving the quality of part quenching.

[0019] Preferably, it also includes a thermal induction temperature control system, and the sensor of the thermal induction temperature control system adopts an infrared thermal sensor; the control signal output end of the thermal induction temperature control system controls the connection of an electric reversing valve, a circulating fan and a vacuum device; at least two infrared thermal sensors are also arranged in the furnace; a hollow high-temperature resistant tube is also arranged corresponding to the infrared thermal sensor, one end of the high-temperature resistant tube is arranged outside the furnace, and the other end is arranged inside the furnace; the infrared thermal sensor is arranged in the part of the high-temperature resistant tube outside the furnace; the photosensitive surface of the infrared thermal sensor faces the other end of the high-temperature resistant tube; a thermal induction temperature control system is used, and the temperature at different positions in the furnace is sensed by the infrared thermal sensor, and then the operating efficiency of the electric reversing valve, the circulating fan and the heating device is adjusted, so that the temperature uniformity in the entire effective area is within ±3 degrees at the same time, the temperature control accuracy of the heat treatment is higher, and the quality of the heat treatment of parts is better. Finally, a high-temperature resistant tube is used to prevent the infrared thermal sensor from directly contacting the high temperature in the furnace and preventing the infrared thermal sensor from being damaged by the high temperature.

[0020] Preferably, a vacuum insulation tube is provided in the high temperature resistant tube, the outer wall of the vacuum insulation tube is tightly fitted with the inner wall of the high temperature resistant tube, and the vacuum insulation tube is arranged at one end close to the infrared sensor; providing the vacuum insulation tube in the high temperature resistant tube can not only protect the infrared heat sensor from being damaged by the high temperature in the furnace, but also prevent the heat in the tempering furnace from escaping.

[0021] Preferably, the tube wall of the vacuum insulated tube is made of ceramic material; both ends of the vacuum insulated tube are sealed with borosilicate glass; ceramic and borosilicate glass are both high temperature resistant materials, and the vacuum insulated tube can maintain insulation and sealing under high temperature and high pressure.

[0022] Preferably, the high temperature resistant tube extends beyond the furnace shell by a length of 80-120 cm; the high temperature resistant tube extends out from the furnace shell to prevent the temperature from being conducted to the infrared thermal sensor and damaging the device.

[0023] Preferably, a stop valve is connected to the exhaust pipe of the vacuum pumping device; the control signal output end of the thermal induction temperature control system is controlled to be connected to the stop valve; by setting the stop valve, after the vacuum pumping device has evacuated the vacuum in the furnace, it is ensured that air will not recoil into the furnace and affect the heat treatment quality of the parts.

[0024] Preferably, the heating element and the insulation layer of the heating device are both made of graphite material, and there are at least two heating elements, which are evenly arranged in the furnace. Through the heating source of the heating element made of graphite material, thermal radiation heating of the parts can be achieved, so that the parts can still be evenly heated in the vacuum furnace.

[0025] Preferably, a sealed furnace cover is provided at the furnace outlet, and the sealed furnace cover is rotatably connected to a connecting bracket, and the connecting bracket is rotatably connected to the furnace shell; by providing the sealed furnace cover, the interior of the furnace is isolated from the external air to prevent the air from affecting the heat treatment quality of the parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0027] Figure 1 A schematic cross-sectional view of an external circulation cooling well type vacuum high pressure gas quenching furnace according to an embodiment of the utility model;

[0028] Figure 2A schematic diagram of the gas flow structure principle of an electric reversing valve in an external circulation cooling well type vacuum high pressure gas quenching furnace according to an embodiment of the utility model;

[0029] Figure 3 In an embodiment of the utility model, an external circulation cooling well type vacuum high pressure gas quenching furnace is provided. Figure 2 Schematic diagram of the structural principle of the electric reversing valve switching the gas direction;

[0030] Figure 4 The present invention is a schematic top view of the structure of an external circulation cooling well type vacuum high pressure gas quenching furnace according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the present invention more understandable, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0034] Secondly, the "one embodiment" or "embodiment" referred to herein refers to a specific feature, structure or characteristic that can be included in at least one implementation of the utility model. The "in one embodiment" that appears in different places in this specification does not refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] Example 1

[0036] Reference Figure 1-Figure 4 This embodiment provides an external circulation cooling pit type vacuum high-pressure gas quenching furnace, including a furnace shell 1, a furnace chamber 2 is arranged in the furnace shell 1, and a heating device 3 is also arranged in the furnace chamber 2.

[0037] The external circulation cooling shaft type vacuum high-pressure gas quenching furnace comprises a furnace shell 1, a furnace chamber 2 is arranged in the furnace shell 1, and a heating device 3 is also arranged in the furnace chamber 2; it also comprises a gas circulation system 4; the circulation fan comprises at least two gas pipelines 5, and a circulation fan driving the gas circulation in at least two gas pipelines; at least two gas delivery ports are arranged at the upper and lower ends of the side of the furnace chamber 2, and the gas delivery pipeline 5 is respectively connected with the gas delivery ports at the upper and lower ends of the furnace chamber 2; the circulation fan also comprises an electric reversing valve 6; two gas source airflow ports 7 are arranged on the gas source side of the electric reversing valve 6; two gas supply airflow ports 8 are arranged on the gas supply side of the electric reversing valve 6; the two gas source airflow ports 7 of the electric reversing valve 6 are respectively connected with the air inlet and air outlet of the circulation fan, and the two gas pipelines 5 are respectively connected with the two gas supply airflow ports 8 of the electric reversing valve 6, so that the air inlet and air outlet of the circulation fan are respectively connected with the two gas pipelines 5; it also comprises a vacuum pumping device 12; the vacuum pipe of the vacuum pumping device 12 is connected to the furnace In the furnace 2; by setting up a gas circulation system, a water-cooling heat sink is provided in the gas circulation system, and the nitrogen gas after cooling can be circulated into the furnace 2 through the gas pipeline 5, and the high-temperature nitrogen gas can be transported away and returned to the gas circulation system for cooling by the water-cooling heat sink, so that the heated parts can be quickly cooled by the circulating cooled nitrogen gas, and the quenching of the parts can be completed quickly; secondly, by setting up an electric reversing valve 6, the flow direction of the circulating nitrogen gas in the furnace 2 is reversed once every 6-12 seconds (from top to bottom to bottom to top, or from bottom to top to top to bottom), so that the direction of the airflow in the furnace can be switched periodically, the uniformity of the temperature in the furnace 2 is improved, the cooling of the top and bottom sides of the slender parts is ensured to be uniform, the deformation is reduced, and the quality of the quenching of the parts is improved; finally, by setting up a vacuum pumping device 12, the air in the furnace 2 is extracted, and then the parts are heated to prevent the air from volatilizing the alloy elements of the parts and affecting the quality of the quenching of the parts.

[0038] Furnace 2 uses a vertical installation method to process slender parts, and adopts a well-type installation method of loading from top to bottom. The equipment is installed by digging a pit in the ground. It does not require high height of the factory building. It can meet the loading needs of slender workpieces (such as screws, gun barrels, rocket launchers, etc.) while occupying very little height space.

[0039] A stop valve is connected to the exhaust pipe of the vacuum device 12; the control signal output end of the thermal induction temperature control system controls the connection of the stop valve; by setting the stop valve, after the vacuum device 12 has evacuated the vacuum in the furnace, it is ensured that air will not recoil into the furnace 2 and affect the heat treatment quality of the parts.

[0040] The heating element and the insulation layer of the heating device 3 are both made of graphite material. There are at least two heating elements, which are evenly arranged in the furnace 2. Through the heating source of the graphite heating element, thermal radiation heating of the parts can be achieved, so that the parts can still be evenly heated in the vacuum furnace 2.

[0041] A sealed furnace cover 11 is provided at the outlet of the furnace chamber 2. The sealed furnace cover 11 is rotatably connected to a connecting bracket, and the connecting bracket is rotatably connected to the furnace shell 1. The sealed furnace cover 11 is provided to ensure that the inside of the furnace chamber 2 is isolated from the external air to prevent the air from affecting the heat treatment quality of the parts.

[0042] When in use, open the sealed furnace cover 11 and put the parts into the furnace 2, close the sealed furnace cover 11, open the stop valve and then open the vacuum device 12 to extract the air in the furnace 2, turn on the circulating fan to maintain low-efficiency operation, keep the water-cooling heat dissipation device closed and slowly introduce some nitrogen, and turn on the heating device 3 to quickly heat up the parts in the low-temperature state, then turn off the circulating fan, and after the temperature of the parts is raised to the insulation austenitization stage through the radiation heating of the heating element, turn off the heating device 3, turn on the water-cooling heat dissipation device, and turn on the circulating fan Rapidly flowing nitrogen and an electric reversing valve 6 (nitrogen flow direction is switched in about 10 seconds) are introduced to quickly raise the nitrogen in the furnace 2 to a rated gas quenching pressure of more than 12 bar. The circulating nitrogen completes the gas quenching and cools the parts. After the air in the furnace 2 is extracted, the parts are heated again to prevent the air from volatilizing the alloy elements of the parts and improve the quality of the quenching of the parts. The direction of the airflow in the furnace can be switched periodically to improve the uniformity of the temperature in the furnace 2, ensure uniform cooling of slender parts at all locations, reduce deformation of parts, and improve the quality of part quenching.

[0043] Example 2

[0044] Reference Figure 1 and Figure 4 , which is the second embodiment of the utility model, and this embodiment is based on the previous embodiment.

[0045] The invention also includes a thermal induction temperature control system, the sensor of which adopts an infrared thermal sensor 9; the control signal output end of the thermal induction temperature control system controls the connection of the electric reversing valve 6, the circulating fan and the vacuum device 12; at least two infrared thermal sensors 9 are arranged in the furnace 2; a hollow high-temperature resistant tube 10 is arranged corresponding to the infrared thermal sensor 9, one end of the high-temperature resistant tube 10 is arranged outside the furnace 2, and the other end is arranged inside the furnace 2; the infrared thermal sensor 9 is arranged in the part of the high-temperature resistant tube 10 outside the furnace 2; the photosensitive surface of the infrared thermal sensor 9 faces the other end of the high-temperature resistant tube 10; the thermal induction temperature control system is used, according to the infrared thermal sensor 9 sensing the temperature of different positions in the furnace 2, and then by adjusting the respective operating efficiencies of the electric reversing valve 6, the circulating fan and the heating device 3, the temperature uniformity in the entire effective area is within ±3 degrees at the same time, the temperature control accuracy of the heat treatment is higher, and the quality of the heat treatment of the parts is better, and finally the high-temperature resistant tube 10 is used to prevent the infrared thermal sensor 9 from directly contacting the high temperature in the furnace and preventing the infrared thermal sensor 9 from being damaged by the high temperature.

[0046] A filter is also provided on the photosensitive surface of the infrared thermal sensor 9 , which only transmits light near a specific wavelength to prevent the radiation light of the heating body from being reflected onto the photosensitive surface and affecting the measurement effect of the infrared thermal sensor 9 .

[0047] A vacuum insulation tube is arranged in the high temperature resistant tube 10, and the outer wall of the vacuum insulation tube is tightly fitted with the inner wall of the high temperature resistant tube 10, and the vacuum insulation tube is arranged at one end close to the infrared sensor; the vacuum insulation tube is arranged in the high temperature resistant tube 10, which can not only protect the infrared heat sensor 9 from being damaged by the high temperature in the furnace, but also prevent the heat in the tempering furnace from escaping.

[0048] The tube wall of the vacuum insulated tube is made of ceramic material; both ends of the vacuum insulated tube are sealed with borosilicate glass; ceramic and borosilicate glass are both high temperature resistant materials, so the vacuum insulated tube can maintain insulation and sealing under high temperature and high pressure.

[0049] The length of the high temperature resistant tube 10 extending beyond the furnace shell 1 is 80-120 cm; the high temperature resistant tube 10 extends out from the furnace shell 1 to prevent the temperature from being conducted to the infrared heat sensor 9 and damaging the device.

[0050] When in use, the infrared thermal sensor 9 of the thermal sensing temperature control system continuously detects the temperature of various parts of the long parts. The frequency of switching the nitrogen flow direction of the electric reversing valve 6 is adjusted according to the temperature state of various parts sensed by the infrared thermal sensor 9, or the nitrogen flow rate is adjusted to prevent the rapid loss of heat at both ends of the parts. The heating element can also be used to radiate the temperature of the parts that lose temperature quickly, so as to ensure uniform cooling of various parts of the slender parts, reduce deformation, and achieve temperature uniformity within ±3 in the entire effective area, thereby improving the quality of heat treatment of the parts. The infrared sensor isolates the high temperature through a vacuum insulation tube and filters the light wave with a filter, so that the infrared sensor can monitor the temperature of various parts of the long parts for a long time, ensure the uniformity of temperature at various parts of the heat treatment of the parts, and improve the gas quenching quality of the long parts.

[0051] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and ratio of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present utility model. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also an equivalent structure. Without departing from the scope of the present invention, other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to a specific embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0052] Additionally, in order to provide a concise description of example embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0053] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0054] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. An external circulation cooling pit type vacuum high pressure gas quenching furnace, comprising a furnace shell, a furnace chamber is arranged in the furnace shell, and a heating device is also arranged in the furnace chamber, characterized in that: Also includes a gas circulation system; The gas circulation system comprises at least two gas pipelines, and a circulation fan for driving gas circulation in the at least two gas pipelines; At least two gas delivery ports are provided at the upper and lower ends of the furnace side, and the gas delivery pipeline is respectively connected to the gas delivery ports at the upper and lower ends of the furnace; The circulating fan also includes an electric reversing valve; Two air source flow ports are provided on the air source side of the electric reversing valve; Two air supply ports are provided on the air supply side of the electric reversing valve; The two air source air flow ports of the electric reversing valve are respectively connected to the air inlet and the air outlet of the circulating fan; The two gas pipelines are respectively connected to the two gas supply ports of the electric reversing valve, so that the air inlet and the air outlet of the circulating fan are respectively connected to the two gas pipelines; Also includes a vacuum device; The vacuum pipe of the vacuum pumping device is connected to the furnace.

2. The external circulation cooling pit type vacuum high pressure gas quenching furnace according to claim 1, characterized in that: It also includes a thermal induction temperature control system, the sensor of which is an infrared thermal sensor; The control signal output end of the thermal induction temperature control system controls the connection of the heating device, the electric reversing valve and the circulating fan; At least two infrared heat sensors are arranged in the furnace; A hollow high-temperature resistant tube is also provided corresponding to the infrared heat sensor, one end of the high-temperature resistant tube is provided outside the furnace, and the other end is provided inside the furnace; The infrared heat sensor is arranged in the part of the high temperature resistant tube outside the furnace; The photosensitive surface of the infrared heat sensor faces the other end of the high temperature resistant tube.

3. The external circulation cooling pit type vacuum high pressure gas quenching furnace according to claim 2 is characterized in that: A vacuum insulation tube is arranged in the high temperature resistant tube, the outer wall of the vacuum insulation tube is closely fitted with the inner wall of the high temperature resistant tube, and the vacuum insulation tube is arranged at one end close to the infrared sensor.

4. The external circulation cooling pit type vacuum high pressure gas quenching furnace according to claim 3 is characterized in that: The tube wall of the vacuum insulation tube is made of ceramic material; Both ends of the vacuum insulation tube are sealed with borosilicate glass.

5. The external circulation cooling pit type vacuum high pressure gas quenching furnace according to claim 4, characterized in that: The length of the high temperature resistant tube extending beyond the furnace shell is 80-120 cm.

6. The external circulation cooling pit type vacuum high pressure gas quenching furnace according to claim 5, characterized in that: A stop valve is connected to the air extraction pipe of the vacuum extraction device; The control signal output end of the thermal induction temperature control system is controlled and connected to the stop valve.

7. The external circulation cooling pit type vacuum high pressure gas quenching furnace according to any one of claims 1 to 6, characterized in that: The heating element and the heat-insulating layer of the heating device are both made of graphite material. There are at least two heating elements, and the heating elements are evenly arranged in the furnace.

8. The external circulation cooling pit type vacuum high pressure gas quenching furnace according to any one of claims 1 to 6, characterized in that: A sealed furnace cover is arranged at the furnace outlet, and the sealed furnace cover is rotatably connected with a connecting bracket, and the connecting bracket is rotatably connected to the furnace shell.

Images