Protection device of infrared temperature measurement sensor and 3D printer

Abstract

The protection device is applied to the technical field of additive manufacturing, the protection device comprises a mounting pipe and an infrared light-transmitting piece, the infrared temperature measurement sensor is sleeved with the mounting pipe, an outward opening, corresponding to the front portion of the infrared temperature measurement sensor, of the mounting pipe is gradually narrowed till an air guide nozzle is formed, and the infrared light-transmitting piece is arranged on the mounting pipe. The infrared light-transmitting piece is arranged in the mounting pipe, the infrared light-transmitting piece is used for separating the gas guide nozzle from the infrared temperature measurement sensor, a first gas inlet is formed in the side wall of the mounting pipe between the gas guide nozzle and the infrared light-transmitting piece, and the first gas inlet is used for filling inert gas into the mounting pipe; and the gas guide nozzle is used for infrared light of the infrared temperature measurement sensor to enter and exit and accelerating inert gas to flow out of the mounting pipe. The time for high temperature of the forming bin to migrate to the infrared temperature measurement sensor body can be shortened, the temperature detection stability of the infrared temperature measurement sensor is improved, and the daily cleaning difficulty is reduced.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and particularly to a protection device for an infrared temperature sensor and a 3D printer. Background Art

[0002] Additive manufacturing technology, also known as three-dimensional printing or rapid prototyping technology, is a method of manufacturing objects by layer-by-layer stacking of materials. As a subdivision of additive manufacturing technology, the selective laser sintering process has developed rapidly in recent years. The selective laser sintering process is a process of circularly laying powder layers on a printing plane and forming patterns by laser sintering the powder layers and stacking them layer by layer to form a three-dimensional entity. This process requires real-time detection of the temperature of the printing plane to determine the surface temperature when heating the powder layer on the printing plane and laser sintering the powder layer on the printing plane. The existing method is to install an infrared temperature sensor outside the forming chamber and extend the probe part of the sensor into the forming chamber. Due to the high temperature of about 200 degrees Celsius in the forming chamber, the high temperature will affect the infrared temperature sensor body through heat migration, and the volatiles generated during the powder laying process and the sintering process, mixed with the high-temperature heat wave, will often stick to the sensor probe, affecting the temperature detection stability and daily cleaning. Utility Model Content

[0003] This application aims to solve at least one of the technical problems existing in the prior art. For this purpose, this application provides a protection device for an infrared temperature sensor and a 3D printer, which can slow down the time for the high temperature in the forming chamber to migrate to the infrared temperature sensor body, improve the temperature detection stability of the infrared temperature sensor, and reduce the difficulty of daily cleaning.

[0004] In a first aspect, this application provides a protection device for an infrared temperature sensor, including:

[0005] An installation pipe, which is used to sleeve on the infrared temperature sensor, and the opening at the end of the installation pipe corresponding to the front of the infrared temperature sensor gradually narrows until a gas guide nozzle is formed;

[0006] An infrared light-transmitting sheet, which is arranged in the installation pipe. The infrared light-transmitting sheet is used to separate the gas guide nozzle from the infrared temperature sensor. A first air inlet is opened on the side wall of the installation pipe between the gas guide nozzle and the infrared light-transmitting sheet. The first air inlet is used to fill the installation pipe with inert gas, and the gas guide nozzle is used for the infrared light of the infrared temperature sensor to enter and exit and accelerate the outflow of the inert gas from the installation pipe.

[0007] The protection device of the infrared temperature sensor according to the first aspect of the present application has at least the following beneficial effects: by providing a mounting tube and forming a gradually narrowing pointed air guide nozzle at the external opening of the mounting tube, the infrared temperature sensor is sheathed in the mounting tube for protection, and at the same time, an infrared light-transmitting sheet for separating the infrared temperature sensor and the air guide nozzle is provided in the mounting tube, so that the infrared light-transmitting sheet and the inner wall of the mounting tube form an inert gas containing chamber, and the air guide nozzle serves as both the outlet of the inert gas containing chamber and the light inlet and outlet of the infrared temperature sensor, forming the optical path of the infrared temperature sensor. At the same time, due to the unique conical surface of the air guide nozzle, the airflow is guided through the inner wall surface of the air guide nozzle to form a vortex, thereby accelerating the discharge from the air guide nozzle. The positive pressure formed by the air guide nozzle to the outside makes it very rare for volatiles in the molding chamber to rise and adhere to the lens of the infrared temperature sensor; and the lens of the infrared temperature sensor does not directly contact the high-temperature heat in the molding chamber. The infrared temperature sensor can be completely installed outside the molding chamber, further reducing the interference of thermal radiation in the molding chamber. At the same time, the inert gas flowing in the inert gas containing chamber will continuously take away the heat in the front area of ​​the infrared temperature sensor probe, so that the thermal radiation emitted by the molding chamber will take a long time to be transferred to the infrared temperature sensor through thermal migration, slowing down the temperature rise time of the infrared temperature sensor itself. Basically, the time taken for one cylinder to be printed will not cause the temperature of the infrared temperature sensor itself to rise to the point of affecting operation. In addition, if the inert gas source fails during the printing process or the inert gas is actively turned off during the machine shutdown process, the volatiles will be blocked by the infrared light-transmitting sheet. Before the inert gas is restored, a cotton swab dipped in alcohol can be inserted into the air guide nozzle to clean the infrared light-transmitting sheet, which is convenient for cleaning the infrared temperature sensor in special circumstances or after printing is completed.

[0008] According to some embodiments of the present application, a second air inlet and a first air outlet are further provided on the inner wall of the mounting tube located between the infrared temperature sensor and the infrared transparent sheet, the second air inlet and the first air outlet are staggered along the axial direction of the mounting tube, the first air outlet is connected to the first air inlet, and the second air inlet is used to connect to an external inert gas source.

[0009] According to some embodiments of the present application, the installation pipe is formed by splicing a plurality of pipe sections, and the infrared temperature sensor and the infrared light-transmitting sheet are respectively arranged in the first and last sections of the plurality of pipe sections.

[0010] According to some embodiments of the present application, the pipe where the infrared transparent sheet is located is made of polyetheretherketone.

[0011] According to some embodiments of the present application, the air guide nozzle and the mounting tube can be separately arranged.

[0012] According to some embodiments of the present application, a first annular cavity wider than its own channel is provided in the mounting tube, and a pressure ring, a lower sealing ring, the infrared transparent sheet, and an upper sealing ring are sequentially provided in the first annular cavity toward the infrared temperature sensor, and the pressure ring is used to apply pressure toward the bottom of the first annular cavity to fix the infrared transparent sheet.

[0013] According to some embodiments of the present application, a second annular cavity is further provided between the first annular cavity and the air guide nozzle, the diameter of the second annular cavity is larger than the diameter of the first annular cavity, and the first air inlet is provided on the side wall of the second annular cavity.

[0014] According to some embodiments of the present application, an interlayer is provided in the side wall of the mounting tube around the infrared temperature sensor, a liquid injection port and a liquid discharge port are provided on the side wall of the interlayer, and the interlayer is used to accommodate and circulate a cooling medium.

[0015] According to some embodiments of the present application, it also includes a mounting plate and a thermal insulation gasket, the mounting plate is provided with a hollow portion, the end of the mounting tube is fixedly connected to the mounting plate through the thermal insulation gasket, the mounting plate is attached to the molding bin, and a clearance hole is opened on the top of the molding bin corresponding to the installation position of the hollow portion.

[0016] In a second aspect, the present application proposes a 3D printer, which includes a protective device for an infrared temperature sensor as described in any one embodiment of the first aspect and the infrared temperature sensor.

[0017] The 3D printer according to the second aspect of the present application has at least the following beneficial effects: By providing an installation pipe and forming a tapered air guide nozzle with a gradually narrowing opening on the outer opening of the installation pipe, the infrared temperature sensor is sleeved and protected inside the installation pipe. At the same time, an infrared transparent sheet is provided inside the installation pipe to separate the infrared temperature sensor and the air guide nozzle, so that an inert gas accommodation cavity is formed between the infrared transparent sheet and the inner wall of the installation pipe. The air guide nozzle serves both as the outlet of the inert gas accommodation cavity and as the light inlet and outlet of the infrared temperature sensor. While forming the optical path of the infrared temperature sensor, due to the unique conical surface of the air guide nozzle, the air flow forms a vortex after being guided by the inner wall surface of the air guide nozzle, thus accelerating the discharge from the air guide nozzle. The positive pressure formed by the air guide nozzle outside makes it very rare for volatiles in the forming chamber to rise and adhere to the lens of the infrared temperature sensor. And the lens of the infrared temperature sensor does not directly contact the high-temperature heat wave in the forming chamber, but is blocked by the infrared transparent sheet. The infrared temperature sensor can be completely installed outside the forming chamber, further reducing the interference of the heat radiation in the forming chamber it receives. At the same time, the inert gas flowing in the inert gas accommodation cavity will continuously take away the heat in the area in front of the probe of the infrared temperature sensor, so that the heat radiation emitted by the forming chamber will take a long time to be transferred to the infrared temperature sensor through heat migration, slowing down the temperature rise time of the infrared temperature sensor itself. Basically, the duration used after one cylinder of printing is completed will not cause the temperature of the infrared temperature sensor itself to rise to an extent that affects its operation. And if the inert gas source fails during printing or the inert gas is actively closed during the process of taking the machine off, the volatiles will be blocked by the infrared transparent sheet. Before the inert gas is restored, the infrared transparent sheet can be cleaned by dipping a cotton swab in alcohol and inserting it into the air guide nozzle, which is convenient for cleaning the infrared temperature sensor in special cases or after printing. Since the 3D printer of the present application includes the protection device for the infrared temperature sensor and the infrared temperature sensor, therefore, it has the same beneficial effects as those in the embodiment of the first aspect.

[0018] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The additional aspects and advantages of the present application will become apparent and be readily understood in conjunction with the following description of the embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 is a schematic side sectional view of the protection device for the infrared temperature sensor according to an embodiment of the present application;

[0021] Figure 2 Regarding the present application Figure 1 is a partial enlarged schematic view of part A in;

[0022] Figure 3Schematic side sectional view of the protection device for the infrared temperature sensor according to another embodiment of the present application;

[0023] Figure 4 Schematic side sectional view of the protection device (equipped with an infrared temperature sensor) for the infrared temperature sensor according to an embodiment of the present application;

[0024] Figure 5 Schematic external structure view of the protection device for the infrared temperature sensor according to some embodiments of the present application.

[0025] The attached reference numerals are as follows:

[0026] Installation pipe 100; first pipe body 110; interlayer 111; liquid injection port 112; liquid discharge port 113; second pipe body 120; first annular cavity 121; second annular cavity 122; first air inlet 123; second air inlet 124; first air outlet 125; pressing ring 126; lower sealing ring 127; upper sealing ring 128; air guiding nozzle 200; infrared light-transmitting sheet 300; infrared temperature sensor 400; heat insulation washer 500; mounting plate 600. Detailed implementation manners

[0027] The embodiments of the present application are described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0028] In the description of the present application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. This is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0029] In the description of the present application, if the first and second are described only for the purpose of distinguishing technical features, they should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0030] In the description of the present application, unless otherwise clearly defined, words such as setting, installation, and connection should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present application in combination with the specific content of the technical solution.

[0031] Refer to Figure 1 、 Figure 2 and Figure 4, In a first aspect, the present application proposes a protection device for an infrared temperature measurement sensor 400, including an installation tube 100 and an infrared light-transmitting sheet 300. In some embodiments, the infrared light-transmitting sheet 300 may be a coated germanium glass. The present application does not limit the material of the infrared light-transmitting sheet 300, and any material that can transmit the infrared light emitted by the selected infrared temperature measurement sensor 400 is acceptable. The installation tube 100 serves as a protective cover for the infrared temperature measurement sensor 400, wrapping and fixing the infrared temperature measurement sensor 400. One end of the installation tube 100 has an outward opening that gradually tapers until a horn-shaped air guide nozzle 200 is formed. It should be noted that the term "tightening" here does not mean tightening infinitely, but rather tightening as much as possible on the premise that the optical path will not be blocked. This data is determined according to the specifications of the selected infrared temperature measurement sensor 400. The infrared light-transmitting sheet 300 is disposed inside the pipeline of the installation tube 100 and is used to separate the flow guide cover from the infrared temperature measurement sensor 400. A first air inlet 123 is provided on the side wall of the installation tube 100 corresponding to the space between the infrared light-transmitting sheet 300 and the air guide nozzle 200. The first air inlet 123 is used to fill inert gas into the space between the infrared light-transmitting sheet 300 and the air guide nozzle 200, and the inert gas is discharged through the air guide nozzle 200.

[0032] Therefore, by providing the mounting tube 100 and forming a gradually narrowing pointed-mouth-shaped air guide nozzle 200 at the opening of the mounting tube 100 to the outside, the infrared temperature sensor 400 is sheathed in the mounting tube 100 for protection, and at the same time, an infrared light-transmitting sheet 300 for separating the infrared temperature sensor 400 and the air guide nozzle 200 is provided in the mounting tube 100, so that the infrared light-transmitting sheet 300 and the inner wall of the mounting tube 100 form an inert gas containing chamber, and the air guide nozzle 200 serves as the outlet of the inert gas containing chamber. It also serves as the light inlet and outlet of the infrared temperature sensor 400, forming the light path of the infrared temperature sensor 400. Due to the unique conical surface of the air guide nozzle 200, the airflow is guided through the inner wall of the air guide nozzle 200 to form a vortex, thereby accelerating the discharge from the air guide nozzle 200. The positive pressure formed by the air guide nozzle 200 to the outside makes it very rare for volatiles in the molding chamber to rise and adhere to the lens of the infrared temperature sensor 400; and the lens of the infrared temperature sensor 400 does not directly contact the high-temperature heat in the molding chamber. The infrared temperature sensor 400 is not in contact with the wave, but is blocked by the infrared light-transmitting sheet 300. The infrared temperature sensor 400 can be completely installed outside the molding chamber, further reducing the interference of the thermal radiation in the molding chamber. At the same time, the inert gas flowing in the inert gas containing chamber will continuously take away the heat in the front area of ​​the infrared temperature sensor 400 probe, so that the thermal radiation emitted by the molding chamber will take a long time to be transferred to the infrared temperature sensor 400 through thermal migration, slowing down the temperature rise time of the infrared temperature sensor 400 itself. Basically, the time used after one cylinder of printing is completed will not cause the temperature of the infrared temperature sensor 400 itself to rise to the point of affecting operation. In addition, if the inert gas source fails during the printing process or the inert gas is actively turned off during the machine shutdown process, the volatiles will be blocked by the infrared light-transmitting sheet 300. Before the inert gas is restored, a cotton swab dipped in alcohol can be inserted into the air guide nozzle 200 to clean the infrared light-transmitting sheet 300, which is convenient for cleaning the infrared temperature sensor 400 in special circumstances or after printing is completed.

[0033] Reference Figure 1 , Figure 3 and Figure 4, it can be understood that a second air inlet 124 and a first air outlet 125 are further provided on the inner wall of the installation pipe 100 between the infrared temperature sensor 400 and the infrared light-transmitting sheet 300. The second air inlet 124 and the first air outlet 125 are arranged staggeredly up and down. The first air outlet 125 is communicated with the first air inlet 123. The second air inlet 124 is used to connect with an external inert gas source. The inert gas filled into the installation pipe 100 first cools the area between the infrared temperature sensor 400 and the infrared light-transmitting sheet 300, and then enters the space between the infrared light-transmitting sheet 300 and the air guide nozzle 200. It should be noted that in some embodiments, due to the different installation positions of the infrared temperature sensor 400 in the installation pipe 100, there is a certain distance between the infrared light-transmitting sheet 300 and it. In this embodiment, by using the cavity formed by this section of distance, this section of air flow path is increased, the coverage area of the air flow is improved, and the effect of making full use of the inert gas and improving the cooling efficiency is further achieved.

[0034] Referring to Figure 3 , it can be understood that in order to facilitate the installation of the infrared temperature sensor 400 into the installation pipe 100, the installation pipe 100 can be spliced by several sections of pipes with different lengths and thicknesses. In this application, taking two sections of pipes as an example, the installation pipe 100 includes a first pipe body 110 and a second pipe body 120 that are detachably connected. The infrared temperature sensor 400 is arranged in the first pipe body 110, and the infrared light-transmitting sheet 300 is arranged in the second pipe body 120. One end of the second pipe body 120 far from the first pipe body 110 gradually tapers to form an air guide nozzle 200. By setting the separated first pipe body 110 and second pipe body 120, the installation of the infrared temperature sensor 400 and the infrared light-transmitting sheet 300 can be carried out independently without interference. This application does not limit the number of split pipes, as long as the number of infrared temperature sensors 400 and infrared light-transmitting sheets 300 that can be installed is feasible.

[0035] Furthermore, the second pipe body 120 is made of polyether ether ketone. It can be understood that polyether ether ketone has high-temperature stability and good processability. Even at a high temperature of 250 degrees Celsius, it can maintain mechanical properties and dimensional stability. Since the second pipe body 120 is the part far from the infrared temperature sensor 400, that is, it is also the part very close to the object to be measured. In this application, that is, it is very close to the high-temperature forming chamber. Therefore, by using this material to manufacture the second pipe body 120, the structural stability and thermal stability of the installation pipe 100 can be ensured, the service life of the installation pipe 100 can be improved, and the processing difficulty can be reduced.

[0036] Referring to Figure 1 and Figure 2, It can be understood that in some embodiments, the air guide nozzle 200 and the installation pipe 100 are detachably arranged. It can be an independently arranged hollow truncated cone, and a skirt is convexly provided on the outer edge of the hollow truncated cone. The hollow truncated cone is detachably connected to the end face of the installation pipe 100 through the skirt. Taking the skirt on the outer edge of the small opening of the hollow truncated cone as an example, the main body part of the hollow truncated cone extends into the channel of the installation pipe 100, and the upper surface of the skirt abuts against the end face of the installation pipe 100, so as to form a connection seal between the large opening of the hollow truncated cone and the installation port. Of course, the position of the skirt is not limited to the lower edge of the hollow truncated cone, and it can also be in the middle or the upper edge. The present application does not make too many limitations, as long as it is set into a structure that is detachable and sealed with the installation pipe 100. Through this structure, the disassembly, installation and replacement of the air guide nozzle 200 can be facilitated.

[0037] Refer to Figure 1 and Figure 2 , It can be understood that a first annular cavity 121 wider than its own channel is provided in the installation pipe 100. A pressure ring 126, a lower sealing ring 127, an infrared light-transmitting sheet 300, and an upper sealing ring 128 are sequentially clamped in the first annular cavity 121 in the direction of the infrared temperature sensor 400. The pressure ring 126 is used to apply pressure towards the bottom of the first annular cavity 121 to fix the infrared light-transmitting sheet 300. This method can ensure the stable installation of the infrared light-transmitting sheet 300 and provide a sealing condition for separating the infrared temperature sensor 400 and the hollow truncated cone.

[0038] Refer to Figure 1 and Figure 2 , Further, a second annular cavity 122 is also provided between the first annular cavity 121 and the air guide nozzle 200. The diameter of the second annular cavity 122 is larger than that of the first annular cavity 121. The first air inlet 123 is arranged on the side wall of the second annular cavity 122. On this basis, the larger the size of the second annular cavity 122, the better. The larger the second annular cavity 122, the more inert gas it can accommodate per unit time, so the positive pressure generated is also greater, and its anti-fouling ability for the infrared light-transmitting sheet 300 is also stronger.

[0039] Refer to Figure 1 , Figure 3 and Figure 4It can be understood that an interlayer 111 is provided around the installation area of ​​the infrared temperature sensor 400 body in the installation tube 100, and the side walls of the interlayer 111 are staggered with injection ports 112 and discharge ports 113. Generally speaking, the opening arranged at the bottom is set as the injection port 112, and the opening arranged at the top is set as the discharge port 113. By injecting a cooling medium with heat absorption capacity such as cold water and refrigerant into the injection port 112 to fill the interlayer 111, heat dissipation is provided for the infrared temperature sensor 400, thereby preventing the external temperature and the heat radiation dissipated from the molding chamber from affecting the temperature measurement accuracy of the infrared temperature sensor 400 itself.

[0040] Reference Figure 5 It can be understood that the infrared temperature measuring device also includes a mounting plate 600 and a thermal insulation gasket 500. The mounting plate 600 is provided with a hollow portion. One end of the mounting tube 100 having the air nozzle 200 is fixedly connected to the mounting plate 600 through the thermal insulation gasket 500. A clearance hole is opened at the mounting position of the hollow portion corresponding to the top of the molding chamber, and the air nozzle 200 is penetrated in the hollow portion and arranged toward the printing plane. By arranging the thermal insulation gasket 500 between the mounting plate 600 and the mounting tube 100, the process of heat radiation in the molding chamber being conducted to the mounting tube 100 and then affecting the infrared temperature measuring sensor 400 can be slowed down, thereby improving the working stability of the infrared temperature measuring device.

[0041] In the second aspect, the present application also proposes a 3D printer, by providing a mounting tube 100, and forming a gradually narrowing pointed mouth-shaped air guide nozzle 200 at the opening of the mounting tube 100 to the outside, the infrared temperature sensor 400 is sleeved in the mounting tube 100 for protection, and at the same time, an infrared transparent sheet 300 for separating the infrared temperature sensor 400 and the air guide nozzle 200 is provided in the mounting tube 100, so that the infrared transparent sheet 300 and the inner wall of the mounting tube 100 form an inert gas containing cavity, and the air guide nozzle 200 serves as The inert gas chamber is the outlet of the inert gas chamber and the light inlet and outlet of the infrared temperature sensor 400. While forming the light path of the infrared temperature sensor 400, due to the unique conical surface of the air guide nozzle 200, the air flow is guided through the inner wall of the air guide nozzle 200 to form a vortex, thereby accelerating the discharge from the air guide nozzle 200. The positive pressure formed by the air guide nozzle 200 to the outside makes it very rare for volatiles in the molding chamber to rise and adhere to the lens of the infrared temperature sensor 400; and the lens of the infrared temperature sensor 400 does not directly contact the infrared temperature sensor 400. The infrared temperature sensor 400 is not exposed to the high-temperature heat wave in the molding chamber, but is blocked by the infrared transparent sheet 300. The infrared temperature sensor 400 can be completely installed outside the molding chamber, further reducing the interference of the thermal radiation in the molding chamber. At the same time, the inert gas flowing in the inert gas containing chamber will continuously take away the heat in the front area of ​​the infrared temperature sensor 400 probe, so that the thermal radiation emitted by the molding chamber will take a long time to be transferred to the infrared temperature sensor 400 through thermal migration, slowing down the temperature rise time of the infrared temperature sensor 400 itself. Basically, the time used after one cylinder of printing is completed will not cause the temperature of the infrared temperature sensor 400 itself to rise to the point of affecting operation. In addition, if the inert gas source fails during the printing process or the inert gas is actively turned off during the machine shutdown process, the volatiles will be blocked by the infrared transparent sheet 300. Before the inert gas is restored, a cotton swab dipped in alcohol can be inserted into the air guide nozzle 200 to clean the infrared transparent sheet 300, which is convenient for cleaning the infrared temperature sensor 400 in special circumstances or after printing is completed. Since the 3D printer of the present application includes a protection device for the infrared temperature sensor 400 and the infrared temperature sensor 400, it has the same beneficial effects as the first aspect embodiment.

[0042] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A protective device for an infrared temperature sensor, characterized in that: include: A mounting tube, the mounting tube being used to be sleeved on the infrared temperature sensor, and the mounting tube gradually narrows in front of the infrared temperature sensor to form an air guide nozzle; An infrared transparent sheet is arranged in the mounting tube, the infrared transparent sheet is used to separate the air guide nozzle from the infrared temperature sensor, a first air inlet is opened on the side wall of the mounting tube between the air guide nozzle and the infrared transparent sheet, the first air inlet is used to fill the mounting tube with inert gas, the air guide nozzle is used for the infrared light of the infrared temperature sensor to enter and exit and to accelerate the inert gas to flow out of the mounting tube.

2. The protection device for an infrared temperature sensor according to claim 1, characterized in that: A second air inlet and a first air outlet are also provided on the inner wall of the mounting tube located between the infrared temperature sensor and the infrared transparent sheet. The second air inlet and the first air outlet are staggered along the axial direction of the mounting tube. The first air outlet is connected to the first air inlet, and the second air inlet is used to be connected to an external inert gas source.

3. The protection device for an infrared temperature sensor according to claim 1, characterized in that: The installation pipe is formed by splicing a plurality of pipe sections, and the infrared temperature measuring sensor and the infrared light-transmitting sheet are respectively arranged in the first and last sections of the pipes among the plurality of pipe sections.

4. The protection device for an infrared temperature sensor according to claim 3, characterized in that: The pipe where the infrared transparent sheet is located is made of polyetheretherketone.

5. The protection device for an infrared temperature sensor according to claim 1, characterized in that: The air guide nozzle and the mounting tube can be arranged separately.

6. The protection device for an infrared temperature sensor according to claim 1, characterized in that: A first annular cavity wider than its own channel is provided in the installation tube, and a pressure ring, a lower sealing ring, the infrared transparent sheet, and an upper sealing ring are sequentially arranged in the first annular cavity toward the infrared temperature sensor, and the pressure ring is used to apply pressure toward the bottom of the first annular cavity to fix the infrared transparent sheet.

7. The protection device for an infrared temperature sensor according to claim 6, characterized in that: A second annular cavity is further provided between the first annular cavity and the air guide nozzle, the diameter of the second annular cavity is larger than the diameter of the first annular cavity, and the first air inlet is provided on the side wall of the second annular cavity.

8. The protection device for an infrared temperature sensor according to claim 1, characterized in that: An interlayer is arranged in the side wall of the installation tube around the infrared temperature measuring sensor, a liquid injection port and a liquid discharge port are arranged on the side wall of the interlayer, and the interlayer is used to accommodate and circulate a cooling medium.

9. The protection device for an infrared temperature sensor according to claim 1, characterized in that: It also includes a mounting plate and a heat-insulating gasket, wherein the mounting plate is provided with a hollow portion, and the end of the mounting tube is fixedly connected to the mounting plate via the heat-insulating gasket, the mounting plate is attached to the molding bin, and a clearance hole is opened at the top of the molding bin corresponding to the installation position of the hollow portion.

10. A 3D printer, characterized in that: The invention comprises a protective device for an infrared temperature measuring sensor as claimed in any one of claims 1 to 9 and the infrared temperature measuring sensor.

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