Air preheater outlet temperature monitoring device

Abstract

The utility model provides an air preheater outlet temperature monitoring device, which comprises a thermocouple and a protective sleeve, the thermocouple is used for monitoring the temperature in an air preheater air duct in real time, and the protective sleeve is sleeved on the periphery of the working end of the thermocouple to play a role in protection, so that the working end is prevented from being influenced by particle collision, abrasion and smoke corrosion, and the service life of the air preheater is prolonged. The service life of the thermocouple is prolonged. A purging gap is formed between the protective sleeve and the working end, in order to prevent excessive smoke dust from being accumulated in the purging gap and affecting the thermocouple and the detection sensitivity, one end of the protective sleeve is provided with a purging hole, the other end of the protective sleeve is provided with an air inlet connector, and the air inlet connector is communicated with compressed air or compressed nitrogen. Accumulated smoke dust can be blown out through the purging hole, and the sensitivity of temperature monitoring is improved. In order to facilitate installation and replacement of the thermocouple, the protective sleeve is provided with an installation part of a flange structure, and the temperature monitoring device can be conveniently and rapidly installed in an air duct of the air preheater through the connecting bolts.

Description

Technical Field

[0001] The utility model belongs to the technical field of temperature monitoring, and in particular relates to an air preheater outlet temperature monitoring device. Background Art

[0002] An air preheater uses the boiler's high-temperature flue gas to preheat the air before it enters the boiler, improving the boiler's heat exchange performance and reducing energy consumption. During cold startup and startup after hot standby, incompletely burned oil and pulverized coal accumulate on the heat storage fins. Since the air preheater is heated by boiler flue gas, the internal temperature can reach 300°C. Any incompletely burned sparks in the flue gas can easily ignite the air preheater's heat storage fins, affecting normal operation. Therefore, a temperature monitoring device is required within the air preheater to monitor the temperature in real time and identify any fire hazards within the air preheater.

[0003] In the prior art, a fire alarm system is composed of multiple thermocouple elements, which are then connected to the air preheater fire alarm system via a DCS system to monitor the internal temperature of the air preheater. The working end of the thermocouple extends deep into the air duct. To protect the working end from the impact and abrasion of particles, as well as corrosion from smoke, a protective sleeve is installed outside the working end to extend the service life of the thermocouple. However, while the protective sleeve provides protection, after prolonged use, smoke and dust easily accumulate in the gap between the protective sleeve and the working end of the thermocouple, affecting heat transfer efficiency and resulting in inaccurate temperature measurements. Utility Model Content

[0004] The utility model provides an air preheater outlet temperature monitoring device, aiming to solve the problem in the prior art that smoke and dust accumulated in a protective sleeve may affect the conduction efficiency of a thermocouple.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide an air preheater outlet temperature monitoring device, comprising:

[0006] a thermocouple having a terminal end and a working end; and

[0007] A protective sleeve is sleeved on the outer circumference of the working end, a purge gap is formed between the interior of the protective sleeve and the working end, the outer wall of the protective sleeve extends outward along its own circumference to form a mounting portion, the mounting portion is a flange structure, the protective sleeve is provided with a purge hole on the side of the mounting portion away from the wiring terminal, the purge hole penetrates the wall thickness of the protective sleeve, the protective sleeve is provided with an air inlet connector on the side of the mounting portion adjacent to the wiring terminal, and the air inlet connector is connected to the purge gap.

[0008] In a possible implementation, the mounting portion is provided with a plurality of mounting holes along its circumference, and the mounting holes penetrate through the thickness direction of the mounting portion.

[0009] In a possible implementation, an end of the working end adjacent to the wiring end is provided with an external thread, and the protective sleeve is threadably connected to the external thread.

[0010] In a possible implementation, the wall thickness of the protective sleeve is 1-3 mm.

[0011] In a possible implementation, a gap between the inner wall of the protective sleeve and the working end is 1-5 mm.

[0012] In a possible implementation, a baffle is further provided at one end of the protective sleeve away from the wiring terminal. The baffle cover is provided at the opening of the protective sleeve, and the baffle is provided with an air vent running through the thickness direction thereof.

[0013] In a possible implementation, the vent is opened at the outer edge of the baffle.

[0014] In a possible implementation, the purge hole is opened on the leeward side of the protective sleeve.

[0015] In a possible implementation, the purge hole is an elongated hole, and the major axis of the purge hole is parallel to the axial direction of the protective sleeve.

[0016] In one possible implementation, the outer peripheral wall of the protective sleeve is further connected to two protective plates, which are arranged opposite to each other in an upper and lower position, one end of the protective plate is connected to the outer wall of the protective sleeve, and the other end extends obliquely upward along the direction of the airflow, and the purge hole is located in the area enclosed by the two protective plates.

[0017] Compared with the prior art, the beneficial effects of the air preheater outlet temperature monitoring device provided by the utility model are:

[0018] The air preheater outlet temperature monitoring device provided by the present invention includes a thermocouple and a protective sleeve. The thermocouple is used to monitor the temperature inside the air duct of the air preheater in real time. The protective sleeve is arranged on the periphery of the working end of the thermocouple to play a protective role, so that the working end is protected from particle collision, wear and smoke corrosion, and the service life of the thermocouple is extended. A purge gap is formed between the protective sleeve and the working end. In order to avoid excessive smoke and dust accumulation in the purge gap and affect the thermocouple and detection sensitivity, the present invention is provided with a purge hole at one end of the protective sleeve and an air inlet connector at the other end. The air inlet connector is connected to compressed air or compressed nitrogen, and can blow out the accumulated smoke and dust through the purge hole, including the sensitivity of temperature monitoring. In order to facilitate the installation and replacement of the thermocouple, a mounting portion with a flange structure is provided on the protective sleeve. The temperature monitoring device can be conveniently and quickly installed in the air duct of the air preheater by connecting bolts. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the installation of an air preheater outlet temperature monitoring device provided by an embodiment of the present utility model;

[0020] Figure 2 The structure diagram of the air preheater outlet temperature monitoring device provided by the embodiment of the utility model Figure 1 ;

[0021] Figure 3 The structure diagram of the air preheater outlet temperature monitoring device provided by the embodiment of the utility model Figure 2 ;

[0022] Figure 4 for Figure 3 Cross-sectional view in the AA direction;

[0023] Figure 5 The structure diagram of the air preheater outlet temperature monitoring device provided by the embodiment of the utility model Figure 3 .

[0024] Description of reference numerals:

[0025] 1. Air preheater outlet temperature monitoring device; 10. Thermocouple; 11. Terminal; 12. Working end; 20. Protective sleeve; 21. Mounting portion; 211. Mounting hole; 22. Baffle; 221. Air vent; 23. Purge hole; 24. Guard plate; 25. Air inlet connector; DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] It should be noted that when an element is referred to as being "fixed to," "fixed," or "fixedly disposed" on another element, it may be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to," "connected to" another element, it may be directly connected to the other element or there may also be an intermediate element. When an element is referred to as being "set on," "disposed on" another element, it may be directly on the other element or there may also be an intermediate element. "Multiple" refers to two or more. "At least one" refers to one or more. "Several" refers to one or more.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0029] Please also refer to Figures 1 to 5 , the air preheater outlet temperature monitoring device 1 provided in an embodiment of the present utility model is described below.

[0030] See also Figure 1 、 Figure 2 、 Figure 3 and Figure 4 ,,An embodiment of the utility model provides an air preheater outlet temperature monitoring device 1, comprising a thermocouple 10 and a protective sleeve 20, the thermocouple 10 having a terminal 11 and a working end 12; the protective sleeve 20 is sleeved on the outer periphery of the working end 12, a purge gap is formed between the interior of the protective sleeve 20 and the working end 12, the outer wall of the protective sleeve 20 extends outward along its own circumference to form a mounting portion 21, the mounting portion 21 is a flange structure, the protective sleeve 20 is provided with a purge hole 23 on the side of the mounting portion 21 away from the terminal 11, the purge hole 23 penetrates the wall thickness of the protective sleeve 20, the protective sleeve 20 is provided with an air inlet connector 25 on the side of the mounting portion 21 adjacent to the terminal 11, and the air inlet connector 25 is connected to the purge gap.

[0031] Compared with the prior art, the air preheater outlet temperature monitoring device 1 provided by the embodiment of the present invention has the following beneficial effects:

[0032] The air preheater outlet temperature monitoring device 1 provided in the embodiment of the present invention includes a thermocouple 10 and a protective sleeve 20. The thermocouple 10 is used to monitor the temperature inside the air duct of the air preheater in real time. The protective sleeve 20 is sleeved on the outer periphery of the working end 12 of the thermocouple 10 to play a protective role, thereby protecting the working end 12 from the influence of particle collision, wear and flue gas corrosion, thereby extending the service life of the thermocouple 10.

[0033] A purge gap is formed between the protective sleeve 20 and the working end 12. To prevent excessive smoke from accumulating in the purge gap and affecting the thermocouple 10 and detection sensitivity, the present embodiment of the utility model has a purge hole 23 at one end of the protective sleeve 20 and an air inlet connector 25 at the other end. The air inlet connector 25 is connected to compressed air or compressed nitrogen, which can blow accumulated smoke out through the purge hole 23, thereby improving the sensitivity of temperature monitoring. To facilitate the installation and replacement of the thermocouple 10, a flange-structured mounting portion 21 is provided on the protective sleeve 20. The temperature monitoring device can be easily and quickly installed in the air duct of the air preheater by connecting bolts.

[0034] like Figure 1 As shown, typically, multiple air preheater outlet temperature monitoring devices 1 are installed in the air duct of the boiler air preheater in a thermal power plant. The thermocouple 10 is electrically connected to the DCS monitoring system. The multiple temperature monitoring devices and the DCS monitoring system constitute a fire alarm system. The DCS can be used to view the temperature conditions at various locations in real time, thereby determining whether there is a fire hazard inside the air preheater, thereby ensuring safe, economical, and reliable operation of the unit.

[0035] In some thermal power plants, the electrical signals from thermocouples 10 are converted by an intermediate thermometer control cabinet before being sent to the DCS. Specifically, an intermediate thermometer is installed between the thermocouples 10 and the DCS. When the temperature element (i.e., the thermocouple 10) detects a sharp temperature rise, it transmits a signal to the intermediate thermometer control cabinet. The intermediate thermometer control cabinet then determines when the temperature reaches the rated value and transmits the signal to the DCS. This approach has drawbacks: operators can only monitor whether the temperature has reached the critical value through the DCS, but cannot monitor the temperature rise process or the specific location, making it impossible to intervene in advance. Furthermore, since the intermediate thermometer control cabinet requires power, a power failure prevents the signal from being transmitted to the DCS, potentially leading to more serious consequences.

[0036] like Figure 1 As shown, in this embodiment, the terminal 11 of the thermocouple 10 is directly connected to the DCS system, eliminating the need for an intermediate temperature meter, simplifying the fire alarm system, and also allowing the DCS system to directly view real-time temperature changes, making the operation and management of the entire power plant more intelligent and integrated.

[0037] The thermocouple 10 can be selected from products with suitable specifications currently available on the market, such as WRN2-430NM-K type thermocouple 10, and one or more can be installed on the air preheater as needed.

[0038] The protective sleeve 20 can be made of a metal tube, and the protective sleeve 20 is sleeved on the outer periphery of the thermocouple 10 to play a protective role. In order to reduce the degree of dust accumulation, the protective sleeve 20 and the thermocouple 10 can be installed at an appropriate tilt angle. The outer periphery of the protective sleeve 20 is provided with a flange-shaped mounting portion 21, which is convenient for fixing on the outer wall of the air preheater air duct. The purge hole 23 is opened on the side wall of the protective sleeve 20 extending into the air duct, so that the working end 12 of the thermocouple 10 can directly contact the air flow in the air duct, the temperature monitoring is more sensitive, and the smoke and dust accumulated in the purge gap during purging can be blown out through the purge port. There is no specific restriction on the size, setting position, number, shape, etc. of the purge port, as long as it can meet the use requirements.

[0039] The air inlet connector 25 is mounted on the protective sleeve 20 and is connected to the gas source via a gas hose for receiving high-pressure gas during purging. Due to the high temperature in the air duct, in order to prevent oxidation of the metal sleeve, the gas source used during purging is preferably an inert gas such as nitrogen.

[0040] See also Figures 2 to 5 In some possible embodiments, the mounting portion 21 has multiple mounting holes 211 formed along its circumference. The mounting holes 211 extend through the thickness of the mounting portion 21 and are used to receive fixing bolts. To prevent air leakage, a sealing gasket or sealant may be provided on the side of the mounting portion 21 that contacts the outer wall of the air duct.

[0041] See also Figure 3 and Figure 4 In some possible embodiments, an external thread is provided at one end of the working end 12 adjacent to the terminal 11, and the protective sleeve 20 is threadedly connected to the external thread. The external thread can be formed by the thermocouple 10 itself or obtained by later processing. The thermocouple 10 and the protective sleeve 20 are connected as one body by a threaded connection, which has a simple structure and a firm and reliable connection.

[0042] In some possible embodiments, the wall thickness of the protective sleeve 20 should not be too thick, otherwise it will affect the monitoring sensitivity of the thermocouple 10. Specifically, it can be 1-3 mm, although other dimensions are also possible. The gap between the inner wall of the protective sleeve 20 and the working end 12 is 1-5 mm, although other dimensions are also possible. The protective sleeve 20 can be made of a material with good thermal conductivity and wear resistance, such as stainless steel.

[0043] See also Figure 5 In some possible embodiments, a baffle 22 is further provided at one end of the protective sleeve 20 away from the terminal 11 . The baffle 22 covers the opening of the protective sleeve 20 , and the baffle 22 has a vent 221 extending through its thickness.

[0044] In this embodiment, the baffle 22 is circular and serves to block the open end of the protective sleeve 20 to prevent excessive smoke and dust from entering. To improve the monitoring sensitivity of the working end 12 and allow smoke and dust to be blown out from the end during purging, the baffle 22 is provided with air vents 221 for inlet and outlet. The location, shape, size, and number of the air vents are not specifically limited.

[0045] See also Figure 5 In some possible embodiments, the air vents are opened at the outer edge of the baffle 22 and have multiple air vents, which are spaced apart along the circumference of the baffle 22 .

[0046] See also Figure 5 In some possible embodiments, the purge hole 23 is opened on the leeward side of the protective sleeve 20. The leeward side and the protective sleeve 20 are installed on the leeward side of the air duct. Opening the purge hole 23 on the leeward side can prevent smoke and dust from directly entering the purge hole 23 from the windward side, reduce the accumulation rate of dust in the protective sleeve 20, and prevent the particles carried by the airflow from hitting the working end 12 through the purge hole 23 and causing wear of the working end 12.

[0047] See also Figure 2 and Figure 5 In some possible embodiments, the purge hole 23 is an elongated hole, and the long axis of the purge hole 23 is parallel to the axial direction of the protective sleeve 20 .

[0048] See also Figure 5 In some possible embodiments, the outer wall of the protective sleeve 20 is further connected to two guard plates 24, and the two guard plates 24 are arranged opposite to each other up and down, one end of the guard plate 24 is connected to the outer wall of the protective sleeve 20, and the other end extends obliquely upward along the direction of the airflow. The purge hole 23 is located in the area enclosed by the two guard plates 24. The two guard plates 24 can guide the airflow to flow along the extension direction of the guard plates 24, reduce the impact of airflow particles on the side of the protective sleeve 20 where the purge hole 23 is opened, and extend the service life of the protective sleeve 20.

[0049] It can be understood that the various parts in the above embodiments can be freely combined or deleted to form different combination embodiments. The specific contents of each combination embodiment will not be repeated here. After this description, it can be considered that the specification of the utility model has recorded various combination embodiments and can support different combination embodiments.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Air preheater outlet temperature monitoring device, characterized in that: include: A thermocouple (10) having a terminal end (11) and a working end (12); as well as A protective sleeve (20) is sleeved on the outer circumference of the working end (12), a purge gap is formed between the interior of the protective sleeve (20) and the working end (12), the outer wall of the protective sleeve (20) extends outward along its own circumference to form a mounting portion (21), the mounting portion (21) is a flange structure, the protective sleeve (20) is provided with a purge hole (23) on the side of the mounting portion (21) away from the terminal (11), the purge hole (23) penetrates the wall thickness of the protective sleeve (20), the protective sleeve (20) is provided with an air inlet connector (25) on the side of the mounting portion (21) adjacent to the terminal (11), and the air inlet connector (25) is communicated with the purge gap.

2. The air preheater outlet temperature monitoring device according to claim 1, characterized in that: The mounting portion (21) is provided with a plurality of mounting holes (211) along its circumference, and the mounting holes (211) penetrate the mounting portion (21) in the thickness direction.

3. The air preheater outlet temperature monitoring device according to claim 1, characterized in that: An end of the working end (12) adjacent to the wiring end (11) is provided with an external thread, and the protective sleeve (20) is threadedly connected to the external thread.

4. The air preheater outlet temperature monitoring device according to claim 1, characterized in that: The wall thickness of the protective sleeve (20) is 1-3 mm.

5. The air preheater outlet temperature monitoring device according to claim 1, characterized in that: The gap between the inner wall of the protective sleeve (20) and the working end (12) is 1-5 mm.

6. The air preheater outlet temperature monitoring device according to claim 1, characterized in that: A baffle (22) is further provided at one end of the protective sleeve (20) away from the terminal (11), and the baffle (22) covers the opening of the protective sleeve (20). The baffle (22) is provided with a vent (221) extending through the thickness of the baffle.

7. The air preheater outlet temperature monitoring device according to claim 6, characterized in that: The vent (221) is opened at the outer edge of the baffle (22).

8. The air preheater outlet temperature monitoring device according to claim 1, characterized in that: The purge hole (23) is opened on the leeward side of the protective sleeve (20).

9. The air preheater outlet temperature monitoring device according to claim 8, characterized in that: The purge hole (23) is a long hole, and the long axis of the purge hole (23) is parallel to the axial direction of the protective sleeve (20).

10. The air preheater outlet temperature monitoring device according to claim 8, characterized in that: The outer peripheral wall of the protective sleeve (20) is further connected to two protective plates (24), which are arranged opposite to each other in an upper and lower direction. One end of the protective plate (24) is connected to the outer wall of the protective sleeve (20), and the other end extends obliquely upward along the direction of airflow. The purge hole (23) is located in the area enclosed by the two protective plates (24).

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