Modular telescopic ceramic hearth temperature measurement structure

Abstract

The application discloses a modular telescopic ceramic hearth temperature measuring structure, which comprises a plurality of hollow cylindrical basic units made of high-temperature-resistant ceramic materials, and adjacent basic units are rigidly connected through convex-concave matching and ceramic shaft pins, so that a temperature measuring structure with adjustable overall length is formed. The shaft centers of the basic units are penetrated to form internal wiring channels, and at least one side wall of the basic units is provided with a through hole and an outer surface solenoid slot which are in communication with the wiring channels, so as to lead out and protect temperature measuring probe leads. The application is suitable for high-temperature, high-dust and strong scouring environments such as a boiler hearth of a thermal power plant, and has the advantages of erosion resistance, corrosion resistance, good lead protection effect and convenient maintenance.

Description

Technical Field

[0001] This invention relates to the field of temperature measurement technology for high-temperature industrial processes, specifically to a temperature measuring device suitable for extreme high-temperature, high-dust, strong-erosion, and corrosive atmospheres. This temperature measuring structure is particularly suitable for real-time temperature monitoring inside the furnace of boilers in thermal power plants, and can also be used in other high-temperature industrial kilns in metallurgy, glass, cement, and other industries. Background Technology

[0002] In large thermal power plants, boiler furnace temperature is a core parameter for assessing combustion status, preventing coking of water-cooled walls, avoiding superheater overheating and tube rupture, and achieving intelligent combustion optimization control. Accurately and continuously acquiring the temperature distribution in different areas of the furnace is of great significance for ensuring unit safety, improving thermal efficiency, and reducing pollutant emissions.

[0003] Currently, thermal power plants commonly use thermocouples as furnace temperature sensors, equipped with metal protective sheaths (such as 310S stainless steel, Inconel 601, etc.). However, the furnace environment of coal-fired boilers is extremely harsh: operating temperatures typically reach 1200–1600°C, filled with high-speed moving ash particles, and the flue gas contains corrosive components such as sulfur, chlorine, and alkali metals, and there is a periodic transition between reducing and oxidizing atmospheres. Under these conditions, traditional metal sheaths face severe challenges: (1) Severe erosion and wear: The continuous scouring of high-speed fly ash causes the sleeve wall thickness to be rapidly reduced, or even perforated, causing the thermocouple to be directly exposed and fail. (2) High temperature creep deformation: Under long-term high temperature, the metal sleeve will creep and bend, affecting the positioning accuracy of the measuring point, and is prone to jamming when withdrawing. (3) Chemical corrosion and oxidation: The active components in coal ash react with the metal, accelerating the corrosion of the casing and shortening its service life. (4) Poor reliability of lead wires: The sensor lead wires are usually exposed from the tail of the structure. They are subjected to high temperature flue gas baking and mechanical stress for a long time at the opening of the furnace wall, which makes them prone to aging and breakage. (5) High maintenance costs: Once damaged, the furnace often needs to be shut down or the load reduced significantly for replacement. Moreover, the integral structure leads to the scrapping of the entire section, resulting in high spare parts costs and long maintenance cycles.

[0004] Although there have been attempts to use integral ceramic protective tubes (such as corundum tubes), their fixed length makes it difficult to adapt to the differences in furnace depth and multi-layer measurement point layout requirements of boilers with different capacities (such as 300MW, 600MW, and 1000MW units); at the same time, the problems of lead wire protection and modular maintenance have not yet been solved.

[0005] Therefore, there is an urgent need for a new temperature measurement solution that combines high reliability, long lifespan, adjustable length, full lead protection, and easy maintenance to meet the stringent requirements of extreme industrial scenarios such as thermal power generation. Purpose of the invention

[0006] This invention aims to provide a modular, extendable ceramic furnace temperature measurement structure, particularly suitable for extreme high-temperature, high-dust, and highly erosive environments such as the furnace of thermal power plant boilers. Through modular ceramic structure design and internal wiring protection, it solves the problems of existing temperature measurement structures, such as easy wear under high-temperature conditions, short service life, non-adjustable overall length, susceptibility of temperature measurement leads to damage from high temperatures and mechanical forces, and difficulty in maintenance and replacement. This improves the reliability and service life of furnace temperature measurement. Technical solution To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a modular, extendable ceramic furnace temperature measuring structure, comprising multiple basic units made of high-temperature resistant, high-hardness ceramic material. Each basic unit is a hollow cylindrical structure. One end of each basic unit has a protrusion or groove, and the other end has a complementary groove or protrusion, allowing adjacent basic units to be joined end-to-end. At least two through holes are provided along the circumferential direction on the mating surface formed by the joining of adjacent basic units. By inserting ceramic pins through these through holes, adjacent basic units are rigidly locked together, thereby forming a temperature measuring structure with an adjustable overall length.

[0008] All basic units have a through-hole at their axis, which extends continuously along the axial direction of the temperature measuring structure, forming an internal wiring channel for laying temperature signal leads. The temperature signal leads are high-temperature resistant metal wires, preferably thermocouple electrode wires or thermocouple compensation wires matched to the temperature probe. The conductor material can be a platinum-rhodium alloy, nickel-based alloy, or other high-temperature resistant metal materials; under oxygen-barrier protection conditions, high-melting-point metal wires such as tungsten wire or molybdenum wire can also be used. The temperature signal leads are continuously laid along the axial through-hole to achieve the extraction and protection of the temperature measurement signal inside the temperature measuring structure.

[0009] At least one basic unit has a through hole extending outward from the axial perforated channel to the outer surface on its side wall, and a helical groove is provided around the outer surface of the basic unit, the helical groove communicating with the through hole. A temperature signal lead can be led out through the axial perforated channel at the end of the temperature measuring structure.

[0010] In one embodiment of the present invention, the foremost basic unit of the modular retractable ceramic furnace temperature measurement structure is used to install a temperature probe. The temperature probe is a temperature sensor suitable for high-temperature environments, and its type can be a thermocouple probe, a fiber optic temperature sensor, or other high-temperature resistant temperature probes, with a thermocouple probe being the preferred embodiment. The temperature-sensing end of the temperature probe is located at the end or side wall opening of the foremost basic unit, so as to be directly exposed to the high-temperature environment of the furnace.

[0011] The signal lead of the temperature probe is connected to a high-temperature resistant metal wire arranged in the hollow channel of the axis, and extends backward along the axial direction of the temperature measuring structure, thereby realizing the transmission and protection of the temperature measuring signal inside the temperature measuring structure. Beneficial effects

[0012] This invention is applicable to harsh environments such as the furnace of thermal power plant boilers and has the following significant advantages: (1) Excellent erosion and corrosion resistance: The all-ceramic structure (preferably high-purity alumina, silicon nitride, etc.) has a hardness far higher than that of ash particles, which can effectively resist high-speed fly ash erosion and chemical corrosion, and its service life far exceeds that of metal sleeves. (2) Length is flexible and adjustable: By increasing or decreasing the number of basic units, any required length (such as 3m, 5m, 8m, etc.) can be quickly assembled on site, perfectly adapting to the temperature measurement needs of different boiler furnace types and multi-layer combustion zones. (3) Fully enclosed protection of the lead wires: Most of the sensor lead wires are located in the axial channel inside the ceramic structure, completely isolating them from external high temperature, dust, flame and mechanical damage, greatly improving the reliability of the system. (4) Stable connection and reliable structure: The modules adopt a double locking mechanism of "convex-concave fit + ceramic shaft pin" to ensure that the temperature measuring structure remains stable under high temperature vibration environment, is not easy to loosen, and is suitable for long-term operation of the furnace. (5) Easy maintenance and low cost: After partial damage (such as corrosion at the front end), only 1-2 basic units need to be replaced, without scrapping the whole unit, which significantly reduces spare parts inventory and downtime maintenance costs. Attached Figure Description Figure 1 This is a three-dimensional structural diagram of the head of a single basic unit of the present invention. Figure 2 This is a three-dimensional structural diagram of the tail of a single basic unit of the present invention. Figure 3 This is a schematic diagram of the structure of the present invention, in which two basic units are connected end to end and fixed by ceramic pivot pins. Figure 4 This is an axial cross-sectional view of the basic unit of the present invention, showing the axial hollow channel and the internal wiring channel. Figure 5 This is a partially enlarged cross-sectional view showing the connection between the through hole on the side wall of the basic unit of the present invention and the spiral groove on the outer surface. Figure 6 This is a schematic diagram of the spiral groove on the outer surface of the basic unit of the present invention. Figure 7 This is a three-view diagram (front view, right view, and top view) of the modular and stretchable ceramic temperature measuring structure of the present invention. Detailed Implementation

[0013] A 600MW subcritical coal-fired boiler requires a furnace temperature measuring point to be installed approximately 7.5 meters above the main combustion zone. Previously, metal-sheathed thermocouples were used, with an average lifespan of less than 4 months. The temperature measuring structure of this invention is modified accordingly. The implementation is as follows: (1) Material selection: The basic unit (1) is made of 99.7% high-purity alumina ceramic, which is sintered at 1700°C and has high hardness (HV≥1500) and excellent thermal shock resistance; the ceramic shaft pin (2) is made of high-strength silicon nitride ceramic. (2) Length customization: Based on the 7.5-meter depth measurement requirement, 15 basic units with a length of 500mm were selected (1) and connected end to end in sequence, and rigidly locked with ceramic pins (2). (3) Sensor integration: The sensing end of an S-type (platinum-rhodium 10-platinum) armored thermocouple is fixed to the end of the frontmost basic unit, and its lead wire (4) is introduced from the sensing end into the axial hollow channel (3) and extends backward. (4) Lead wires are led out: On the side wall of the end basic unit, the lead wires (4) pass through the through holes (5) and are embedded in the spiral grooves (6) on the outer surface. They are spirally arranged to the end of the structure and connected to the furnace external junction box with cooling air. (5) Installation and sealing: The temperature measuring structure is vertically inserted into the boiler wall through a special water-cooled installation sleeve. A high-temperature metal spiral wound gasket is used to seal between the sleeve and the boiler wall to ensure that the 1600°C high-temperature flue gas does not leak out.

[0014] After the modular and retractable ceramic furnace temperature measurement structure of this invention was put into operation, it was used continuously and stably for more than 18 months. The temperature measurement data was accurate and the response was rapid. There were no interruptions caused by scouring, corrosion or lead wire failure, which provided reliable data support for boiler combustion optimization and anti-coking control.

[0015] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modular, retractable ceramic furnace temperature measurement structure, characterized in that, include: (1) At least two basic units made of high-temperature resistant ceramic material, each basic unit being a hollow cylinder; (2) One end of the basic unit is provided with a protrusion or groove structure, and the other end is provided with a groove or protrusion structure that complements and matches the protrusion or groove. (3) At least two through holes are provided along the circumferential direction on the mating surface formed by the protrusion or groove structure and the corresponding groove or protrusion structure; (4) Used to insert ceramic pins through the through hole to rigidly lock adjacent basic units together; (5) The axis of all basic units is designed as a through-hole channel for internal wiring. (6) A through hole extending outward from the axial hollow channel to the outer surface is provided on the side wall of the basic unit, and a helical groove is provided around it, which communicates with the through hole.

2. The modular, retractable ceramic furnace temperature measurement structure according to claim 1, characterized in that, The basic unit is made of alumina ceramic or silicon nitride ceramic material.

3. The modular, retractable ceramic furnace temperature measurement structure according to claim 1, characterized in that, The ceramic axle pin is made of alumina ceramic or silicon nitride ceramic material.

4. The modular, retractable ceramic furnace temperature measuring structure according to any one of claims 1 to 3, characterized in that, It also includes a temperature probe, the temperature sensing end of which is located at the end or side wall opening of the frontmost basic unit, and the signal lead of the temperature probe extends backward and is led out along the axial hollow channel.

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