CN111380619A - A closed-loop water-cooled thermocouple based on 3D printing microchannel - Google Patents

Abstract

The invention relates to a 3D printing microchannel closed circulating water-cooled thermocouple, which belongs to the technical field of temperature measurement under high temperature and strong corrosive environment. Insulating sleeve, temperature measuring probe and junction box; 3D printing micro-channel water-cooling protective sleeve is set on the outer periphery of thermocouple wire and insulating sleeve, and the protective sleeve is connected to the closed water-cooling circulation cooling system through the cooling water pipe; thermocouple wire and One end of the insulating sleeve is provided with a temperature measuring probe, and the other end is provided with a junction box. The invention effectively solves the problem of easy corrosion and deformation of the thermocouple protection sleeve under the high temperature and high corrosion environment by adopting the 3D printing microchannel water-cooling protection sleeve, and at the same time adopts the closed circulating water to cool the protection sleeve, thereby improving the service life of the thermocouple; Cost-effective and expand the use of thermocouples.

Description

A closed-loop water-cooled thermocouple based on 3D printing microchannel

technical field

The invention relates to a closed-loop water-cooled thermocouple based on 3D printing micro-channels, and belongs to the technical field of temperature measurement under high temperature and strong corrosive environment.

Background technique

Thermocouples have the advantages of high measurement accuracy, wide measurement range, simple structure and low price, and are widely used in weak corrosive contact temperature measurement fields in chemical, electric power and other industries. However, in high temperature and strong corrosive flue gas environments such as waste incineration boilers and hazardous waste boilers, conventional high-grade stainless steel and rare metal-containing special alloy thermocouple protection sleeves are not only expensive, but also face the problem of rapid corrosion, resulting in a short service life of the thermocouple. , the replacement frequency is high. In addition, the larger the measured section is, the more uneven the flow field distribution of flue gas and other media is. In order to obtain more accurate measurement results, the longer the insertion length of the thermocouple is required, which is easy to cause deformation of the thermocouple in a high temperature and strong corrosive environment. Seriously, the hot electrode is damaged or cannot be pulled out during replacement. Therefore, there is an urgent need in the technical field to effectively solve the problems of corrosion and deformation of thermocouple protection sleeves in a high temperature and high corrosion environment.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the technical problem of easy corrosion and deformation of the thermocouple protective sleeve under the high temperature and high corrosion environment.

In order to achieve the purpose of solving the above-mentioned problems, the technical solution adopted by the present invention is to provide a closed-loop water-cooled thermocouple based on 3D printing microchannel, including 3D-printed microchannel water-cooling protection sleeve, closed-loop water-cooling circulation cooling system, and thermocouple. Wire and insulating sleeve, temperature measuring probe and junction box; the outer periphery of the thermocouple wire and insulating sleeve is provided with a 3D-printed micro-channel water-cooling protection sleeve, and the 3D-printed micro-channel water-cooling protection sleeve passes through the cooling water pipe and the closed water cooling A circulating cooling system is connected; one end of the thermocouple wire and the insulating sleeve is provided with a temperature measuring probe, and the other end is provided with a junction box.

Preferably, the 3D-printed microchannel water-cooling protective sleeve is set in a cylindrical shape, and the inner wall of the 3D-printed microchannel water-cooled protective sleeve is provided with an annular ring-shaped cylindrical wall on the side close to the temperature measuring probe. A backwater mixing tank; an annular water inlet distribution tank and an annular return water confluence tank, which are not connected to each other, are respectively provided in the cylindrical wall of the 3D printed microchannel water-cooling protection sleeve on the side away from the temperature measuring probe; Between the annular inlet and return water mixing tank and the annular water inlet distribution tank, there is a water inlet slightly cooling channel; between the annular inlet and return water mixing tank and the annular return water confluence tank is a return water slightly cooling channel.

Preferably, the cylindrical wall of the 3D printed micro-channel water-cooling protection sleeve is provided with four water inlet micro-cooling channels along the axial direction, and the water inlet micro-cooling channels are evenly arranged on the circumference of the cylindrical wall; Between the water micro-cooling channels, return water micro-cooling channels are arranged; the return water micro-cooling channels are evenly arranged on the circumference of the cylinder wall.

Preferably, the closed water-cooling circulating cooling system includes a circulating water tank, a circulating water pump, a cooling water inlet ball valve, a check valve and an air cooler; the cooling water inlet pipe provided in the annular water inlet distribution tank is connected to the cooling water inlet ball valve through the cooling water inlet ball valve. The circulating water tank is connected; a circulating water pump is arranged between the cooling water inlet ball valve and the circulating water tank; There is a check valve.

Preferably, a pressure gauge is arranged between the circulating water pump and the cooling water inlet ball valve, and a cooling water outlet thermometer is arranged between the cooling water outlet pipe and the check valve.

Preferably, the circulating water tank is provided with an electric contact level gauge for detecting the water level, and the circulating water tank is filled with water through a water replenishing ball valve.

Preferably, the distance between the annular inlet and return water mixing tank of the 3D printed microchannel water-cooling protection sleeve and the end of the thermocouple wire is set to be less than or equal to 20 cm.

Preferably, a temperature measuring probe is provided at the end of the 3D printed microchannel water-cooling protection sleeve and the annular inlet and return water mixing tank; the outer surface of the temperature measuring probe is provided with a Ni-Cr-W cladding coating.

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

The invention is a closed circulation water-cooled thermocouple based on 3D printing micro-channel, and the main body is composed of a 3D-printed micro-channel water-cooling protection sleeve, a closed-type water-cooling circulation cooling system, a thermocouple wire, an insulating sleeve, and a junction box. The use of 3D printed micro-channel water-cooled protection sleeves and closed-circuit water-cooled protection sleeves can effectively solve the problem of corrosion and deformation of thermocouple protection sleeves in high temperature and high corrosive environments, thereby improving the service life of thermocouples; cost-effective and can expand Thermocouples can be used to replace expensive smoke temperature probes and infrared thermometers.

Description of drawings

1 is a schematic structural diagram of a 3D printing microchannel closed-loop water-cooled thermocouple of the present invention;

Fig. 2 is the schematic diagram of the closed water-cooled circulation cooling system of the present invention;

3 is a schematic structural diagram of the 3D printing microchannel water-cooling protective sleeve of the present invention;

4 is a cross-sectional view A-A of the 3D printing microchannel water-cooling protective sleeve of the present invention;

FIG. 5 is a B-B cross-sectional view of the 3D printing microchannel water-cooling protective sleeve of the present invention;

Reference numerals: 1. 3D printed micro-channel water-cooled protective sleeve 2. Closed water-cooled circulation cooling system 3. Thermocouple wire and insulating sleeve 4. Junction box 5. 3D-printed micro-channel water-cooled protective sleeve water-cooled connecting pipe 6. Cooling water Outlet thermometer 7. Check valve 8. Air cooler 9. Water supply ball valve 10. Electric contact level gauge 11. Circulating water tank 12. Circulating water pump 13. Pressure gauge 14. Cooling water inlet ball valve 15. Inlet water cooling channel 16. Return Water cooling channel 17. Annular water inlet distribution tank 18. Annular return water confluence tank 19. Inlet and return water mixing tank 20. Temperature measuring probe 21. Connection thread 22. Fixed flange 23. Cooling water inlet pipe 24. Cooling water outlet take over.

Detailed ways

In order to make the present invention more obvious and easy to understand, preferred embodiments are hereby described in detail with the accompanying drawings as follows:

As shown in Figures 1-5, the present invention provides a closed-loop water-cooled thermocouple based on 3D printing micro-channel, including a 3D-printed micro-channel water-cooled protective sleeve 1, a closed-type water-cooled circulating cooling system 2, a thermocouple wire and an insulating sleeve Tube 3, temperature measuring probe 20 and junction box 4; thermocouple wire and insulating sleeve 3 are provided with 3D-printed micro-channel water-cooling protection sleeve 1 on the outer periphery, and 3D-printed micro-channel water-cooling protection sleeve 1 is protected by 3D-printed micro-channel water-cooling The casing water-cooling connecting pipe 5 is connected to the closed water-cooling circulating cooling system 2; one end of the thermocouple wire and the insulating casing 3 is provided with a temperature measuring probe 20, and the other end is connected with a junction box 4. The 3D printing microchannel water-cooling protection casing 1 is provided with In the shape of a cylinder, the 3D-printed micro-channel water-cooling protection sleeve 1 is provided with an annular inlet and return water mixing tank 19 on the side of the cylinder wall close to the temperature measuring probe 20; the 3D-printed micro-channel water-cooling protection sleeve The side of the cylinder wall away from the temperature measuring probe 20 is respectively provided with an annular water inlet distribution groove 17 and an annular return water confluence groove 18 that are not connected to each other around the cylindrical wall; the annular inlet and return water mixing groove 19 and the annular inlet water distribution Between the grooves 17 is provided a water inlet micro-cooling channel 15; between the annular inlet and return water mixing tank 19 and the annular return water confluence tank 18 is provided a return water micro-cooling channel 16. 3D printing the cylinder of the micro-channel water-cooling protection sleeve 1 Four inlet water micro-cooling channels 15 are arranged in the axial direction in the cylinder wall, and the water inlet micro-cooling channels 15 are evenly arranged on the circumference of the cylinder wall; between the water inlet micro-cooling channels 15, there are return water micro-cooling channels 16; The return water micro-cooling channel 16 is evenly arranged on the circumference of the cylinder wall. The closed water-cooled circulating cooling system 2 includes a circulating water tank 11, a circulating water pump 12, a cooling water inlet ball valve 14, a check valve 7 and an air cooler 8; the cooling water inlet pipe 23 provided in the annular water inlet distribution tank 17 passes through the cooling water inlet ball valve 14 is connected to the circulating water tank 11; a circulating water pump 12 is arranged between the cooling water inlet ball valve 14 and the circulating water tank 11; A check valve 7 is provided between the outlet nozzle 24 and the air cooler 8 . A pressure gauge 13 is arranged between the circulating water pump 12 and the cooling water inlet ball valve 14 , and a cooling water outlet thermometer 6 is arranged between the cooling water outlet pipe 24 and the check valve 7 . The circulating water tank 11 is provided with an electric contact level gauge 10 for detecting the water level, and the circulating water tank 11 is filled with water through the water replenishing ball valve 9 . The distance between the annular inlet and return water mixing tank 19 of the 3D printed microchannel water-cooling protection sleeve 1 and the end of the thermocouple wire is set to be less than or equal to 20 cm. A temperature measuring probe 20 is provided at the end of the 3D printed micro-channel water-cooling protection sleeve 1 adjacent to the annular inlet and return water mixing tank 19 ; the outer surface of the temperature measuring probe 20 is provided with a Ni-Cr-W cladding coating.

As shown in Figure 1, the 3D printed microchannel water-cooled protective sleeve 1 is inserted into the medium to be measured, and the medium temperature is transmitted to the thermocouple wire and the insulating sleeve 3 through the 3D printed microchannel water-cooled protective sleeve 1, and the thermocouple wire and the insulating sleeve. The tube 3 converts the temperature signal into a thermoelectromotive force signal, and transmits the temperature signal to the external equipment through the junction box 4. The closed water-cooled circulation cooling system 2 uses demineralized water to force circulation to cool the 3D printed micro-channel water-cooled protective sleeve 1 to avoid deformation and rapid corrosion of the protective sleeve.

As shown in FIG. 2 , the circulating water tank 11 stores demineralized water, and the electric contact liquid level gauge 10 can be used to give an alarm prompt for the liquid level. The cooling water is transported to the water-cooling connecting pipe 5 of each 3D-printed micro-channel water-cooling protection sleeve through the circulating water pump 12, and the cooling water heated by the 3D-printed micro-channel water-cooling protection sleeve 1 is sent to the air cooler 8 for natural air cooling and then returned to the air cooler. Circulating water tank 11. The cooling water-air cooler 8 is a heat exchanger with a high surface area ratio, which can cool the cooling water with the design flow to about 40° C. under the condition of natural ventilation in the workshop. When commissioning for the first time, the output of the circulating water pump 12 and the opening of the cooling water inlet ball valve 14 should be combined to keep the temperature displayed by the cooling water outlet thermometer 6 at about 80°C to prevent the cooling water from being too small to boil in the microchannel and reduce the cooling effect. During the operation stage, the cooling water outlet thermometer 6 has a fault alarm function. When the temperature is lower than 45°C, it is necessary to check whether the 3D printed microchannel water cooling protection sleeve is blocked or damaged and leaked in combination with the value change of the electrical contact level gauge 10. The cooling water outlet pipeline is provided with a check valve 7, and by closing the cooling water inlet ball valve 14, the corresponding branch 3D printing microchannel water cooling protection sleeve can be repaired and replaced.

As shown in FIG. 3 , the connecting thread 21 is used for connecting the junction box, and the fixing flange 22 is used for assembling and fixing the 3D printed microchannel water-cooling protection sleeve 1 . The water cooling area casing is manufactured by 3D printing technology, and the material is conventional 304 stainless steel. Its structure is as follows: the diameter of the water inlet micro-cooling channel 15 is 2mm, which starts from the annular water inlet distribution tank 17 and ends at the inlet and return water mixing tank 19. The water distribution tank 17 communicates with the cooling water inlet pipe 23 . The diameter of the return water micro-cooling channel 16 is 2 mm, starting from the inlet and return water mixing tank 19 and ending at the annular return water confluence tank 18, which communicates with the cooling water outlet pipe 24. In order to ensure the measurement accuracy, the distance between the inlet and return water mixing tank 19 is about 20cm from the end of the thermocouple wire, and the rear end of the inlet and return water mixing tank 19 is a temperature measuring probe 20 with a length of about 25cm. The outer surface of the temperature measuring probe 20 adopts laser cladding 2mm thick Ni-Cr-W cladding coating to improve wear resistance and corrosion resistance.

The present invention is composed of a 3D printing micro-channel water-cooling protection sleeve 1 , a closed water-cooling circulating cooling system 2 , a thermocouple wire and an insulating sleeve 3 , and a junction box 4 . It can be used for temperature measurement in high temperature and strong corrosive flue gas environments such as waste incineration boilers and hazardous waste boilers. The thermocouple wire, insulating sleeve and junction box are the same as conventional thermocouples, but the micro-channel water-cooling protection sleeve is manufactured by using 3D printing technology. And a set of simple and reliable closed water cooling circulation cooling system with low energy consumption, so that the thermocouple of the present invention can measure the temperature in the high temperature and strong corrosive flue gas environment. The 3D printed microchannel water-cooling protective sleeve 1 has a wall thickness of about 4mm, and 8 water-cooling channels with a diameter of 2mm are evenly distributed in the circumferential direction. The water inlet flow channel starts from the annular water inlet distribution tank 17 and ends at the inlet and return water mixing tank 19 . The annular water inlet distribution tank 17 is communicated with the cooling water inlet pipe 23 . The return water flow channel starts from the inlet and return water mixing tank 19 and ends at the annular return water confluence tank 18 , which communicates with the cooling water outlet pipe 24 . In order to ensure the measurement accuracy, the distance between the inlet and return water mixing tank 19 is about 20cm from the end of the thermocouple wire, and the rear end of the inlet and return water mixing tank 19 is a non-water-cooled temperature measuring probe (about 25cm in length). The casing material is all conventional 304 stainless steel, but the outer surface of the temperature measuring probe is additionally coated with a 2mm thick Ni-Cr-W coating by laser cladding to improve wear resistance and corrosion resistance. The closed water cooling circulation cooling system is mainly composed of a circulating water tank 11, a circulating water pump 12, an air cooler 8, pipes and valve instruments. The cooling water flow rate of each 3D-printed micro-channel closed-loop water-cooled thermocouple is about 10-30kg/h, so a closed-loop water-cooled circulation cooling system can use parallel pipelines to cool multiple 3D-printed micro-channel closed-loop water-cooled thermocouples . Demineralized water should be used for cooling water to prevent fouling from clogging the micro-cooling channel. Since it is a closed circulation system, it is not necessary to supplement demineralized water under normal circumstances.

When working, the closed circulation cooling water process is as follows: the cooling water is sent to the annular water inlet distribution tank 17 of the 3D printed microchannel water-cooling protection sleeve 1 through the pipeline by the circulation pump 12, and then enters the 4 water inlet micro-cooling channels after distribution. 15, and then reach the inlet and return water mixing tank 19; after redistribution in the inlet and return water mixing tank 19, it enters 4 return water micro-cooling channels 16, and finally passes through the annular return water confluence tank 18 and is sent to the air cooler 8 through pipelines. The water cooled by the air in the workshop environment is returned to the circulating water tank 11 to complete a circulating process. When commissioning for the first time, the output of the circulating water pump 12 and the opening of the cooling water inlet ball valve 14 should be combined to keep the temperature displayed by the cooling water outlet thermometer 6 at about 80°C to prevent the cooling water from being trapped in the microchannel and reducing the cooling effect. During the operation stage, attention should be paid to the low temperature alarm of the cooling water outlet thermometer 6. If the temperature is lower than 50 °C, the value change of the electric contact water level meter 10 of the circulating water tank should be combined to check whether the 3D printed microchannel water cooling protection sleeve is blocked or damaged or leaked.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form or substance. It should be pointed out that those of ordinary skill in the art can also Several improvements and additions have been made, and these improvements and additions should also be regarded as the protection scope of the present invention. All those skilled in the art, without departing from the spirit and scope of the present invention, can utilize the above-disclosed technical content to make some changes, modifications and equivalent changes of evolution, all belong to the present invention. Equivalent embodiments; at the same time, any modification, modification and evolution of any equivalent changes made to the above embodiments according to the essential technology of the present invention still fall within the scope of the technical solutions of the present invention.

Claims (8)

1. The utility model provides a print microchannel closed circulation water-cooling thermocouple based on 3D, its characterized in that: the device comprises a 3D printing micro-channel water-cooling protective sleeve, a closed water-cooling circulating cooling system, a thermocouple wire, an insulating sleeve, a temperature measuring probe and a junction box; the periphery of the thermocouple wire and the insulating sleeve is sleeved with a 3D printing micro-channel water-cooling protective sleeve, and the 3D printing micro-channel water-cooling protective sleeve is connected with a closed water-cooling circulating cooling system through a cooling water pipe; one end of the thermocouple wire and one end of the insulating sleeve are provided with temperature measuring probes, and the other end of the thermocouple wire and the insulating sleeve are provided with a junction box.

2. The closed circulation water-cooled thermocouple based on the 3D printing micro-channel is characterized in that: the 3D printing micro-channel water-cooling protective sleeve is in a cylindrical shape, and an annular water inlet and return mixing tank with a cylindrical wall is arranged in the cylindrical wall of the 3D printing micro-channel water-cooling protective sleeve and close to one side of the temperature measuring probe; an annular water inlet distribution groove and an annular water return convergence groove which are not communicated with each other and are formed in the side, far away from the temperature measuring probe, of the cylindrical wall of the 3D printing micro-channel water-cooling protective sleeve; a water inlet micro-cooling channel is arranged between the annular water inlet and return mixing tank and the annular water inlet distribution tank; and a return water micro-cooling channel is arranged between the annular inlet return water mixing tank and the annular return water merging tank.

3. The closed circulation water-cooled thermocouple based on the 3D printing micro-channel as claimed in claim 2, wherein: 4 water inlet micro-cooling channels are axially arranged in the cylinder wall of the 3D printing micro-channel water-cooling protective sleeve, and are uniformly arranged on the circumference of the cylinder wall; a backwater micro-cooling channel is arranged between the water inlet micro-cooling channels; the backwater micro-cooling channels are uniformly arranged on the circumference of the cylinder wall.

4. The closed circulation water-cooled thermocouple based on the 3D printing micro-channel is characterized in that: the closed water-cooling circulating cooling system comprises a circulating water tank, a circulating water pump, a cooling water inlet ball valve, a check valve and an air cooler; a cooling water inlet connecting pipe arranged on the annular water inlet distribution groove is connected with the circulating water tank through a cooling water inlet ball valve; a circulating water pump is arranged between the cooling water inlet ball valve and the circulating water tank; and a cooling water outlet connecting pipe arranged on the annular water return merging groove is connected with the circulating water tank through an air cooler, and a check valve is arranged between the cooling water outlet connecting pipe and the air cooler.

5. The closed circulation water-cooled thermocouple based on the 3D printing micro-channel is characterized in that: and a pressure gauge is arranged between the circulating water pump and the cooling water inlet ball valve, and a cooling water outlet thermometer is arranged between the cooling water outlet connecting pipe and the check valve.

6. The closed circulation water-cooled thermocouple based on the 3D printing micro-channel is characterized in that: the circulating water tank is provided with an electric contact liquid level meter for detecting the water level, and the circulating water tank is used for supplementing water through a water supplementing ball valve.

7. The closed circulation water-cooled thermocouple based on the 3D printing micro-channel as claimed in claim 6, wherein: the distance between the annular water inlet and return mixing tank of the 3D printing micro-channel water-cooling protective sleeve and the tail end of the thermocouple wire is set to be less than or equal to 20 cm.

8. The closed circulation water-cooled thermocouple based on the 3D printing micro-channel as claimed in claim 6, wherein: the end part of the 3D printing micro-channel water-cooling protective sleeve adjacent to the annular water inlet and return mixing tank is provided with a temperature measuring probe; the outer surface of the temperature measuring probe is provided with a Ni-Cr-W cladding coating.

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