A method for calibrating and evaluating the small flame temperature of an igniter based on ignition tests.

Abstract

This invention discloses a method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test, comprising the following steps: (1) generating a small flame for the ignition test; (2) moving the temperature probe of the calibration system to a designated position; (3) entering calibration information into the calibration system; (4) igniting the igniter and automatically collecting flame temperature data; (5) extinguishing the igniter and cooling the temperature probe; (6) recording and calculating the flame heating time and the effective absorbed heat power of the temperature probe during the ignition test; (7) calculating the flame heating time ∆t and the effective absorbed heat power P of the temperature probe based on the obtained flame heating time ∆t and the effective absorbed heat power P of the temperature probe. 有效 Combined with the theoretical thermal power P of the gas 理论 =Flow rate × Calorific value of gas, calculate the heat transfer efficiency η of the temperature probe η=P 有效 / P 理论 This invention determines whether the flame temperature of the igniter meets the requirements. It effectively ensures the validity of the data and is applicable to the calibration and evaluation of different types of igniters.

Description

Technical Field

[0001] This invention relates to the field of flame assessment, and more specifically to a method for calibrating and assessing the small flame temperature of an igniter based on an ignition test. Background Technology

[0002] Current technologies calibrate flames through ignition tests. For small flames used in ignition tests, the flame is currently calibrated only by adjusting the gas flow rate or flame height (visual inspection method), and flame temperature calibration is usually not performed. Furthermore, there is a lack of effective calibration schemes for flame temperature calibration. The subjective method of judging flame size by visual inspection relies heavily on the experience of the test personnel, which has drawbacks such as significant subjective influence, failure to consider the flame's heating rate and ignition energy, and frequent large fluctuations in test results across different equipment or test personnel.

[0003] In some ignition tests, technicians directly measure the temperature of the flame by inserting a handheld thermally conductive temperature probe or measuring tool into it. This method is a temporary operation; the large swing amplitude of the temperature probe leads to significant drift in the measured temperature data, resulting in inaccurate results that cannot be used for flame calibration. Furthermore, it suffers from numerous drawbacks, including inconvenience in use and the ease with which the measuring tools can be damaged. Summary of the Invention

[0004] To at least partially address the shortcomings of the prior art, the main objective of this invention is to provide a method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test.

[0005] To achieve the above-mentioned main objectives, this invention discloses a method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test, comprising the following steps: (1) Ignite the igniter for the first time, adjust the pressure and flow of the igniter to generate a small flame for the ignition test, and extinguish the igniter after the flame height of the igniter is adjusted. (2) Move the temperature probe of the calibration system horizontally so that the temperature probe is directly above the flame produced by the igniter, and move the temperature probe vertically so that the top of the temperature probe and the igniter are at the corresponding height positions. (3) Enter calibration information into the calibration system and set the calibration start temperature T1 and calibration end temperature T2; wherein, the calibration information includes flame height, gas type and gas flow rate; (4) Ignite the igniter again and automatically collect flame temperature data through the thermometer connected to the temperature probe in the calibration system. When the flame temperature reaches the calibration start temperature T1, the timing module in the calibration system starts timing to obtain time t1. When the flame temperature reaches the calibration end temperature T2, the timing module in the calibration system starts timing to obtain time t2. (5) Extinguish the igniter and cool down the temperature probe; (6) Record and calculate the flame heating time and the effective heat absorption power of the temperature probe during the ignition test; Wherein, the flame heating time ∆t is the time it takes for the flame temperature to rise from the calibration start temperature T1 to the calibration end temperature T2, that is, ∆t=t2-t1; The effective heat absorption power P of the temperature probe 有效 =m*c*∆T / ∆t, where: m is the mass of the temperature probe, c is the specific heat capacity of the temperature probe, and ∆T is the temperature difference between the calibration endpoint temperature T2 and the calibration starting temperature T1; (7) Based on the obtained flame heating time ∆t and the effective absorbed heat power P of the temperature probe 有效 Combined with the theoretical thermal power P of the gas 理论 =Flow rate × Calorific value of gas, calculate the heat transfer efficiency η of the temperature probe η=P 有效 / P 理论 This determines whether the flame temperature of the igniter meets the requirements.

[0006] In the above technical solution of the present invention, the flame height of the igniter is first adjusted to generate a suitable small flame for ignition test. Then, the position of the temperature probe is precisely adjusted by the calibration system. In the subsequent ignition test, the position between the temperature probe and the igniter does not change, which effectively ensures the validity of the temperature data during the test and thus improves the test results.

[0007] Furthermore, the calibration system comprehensively assesses the flame's heating time (heating rate) and the effective heat absorption power of the temperature probe during the ignition test from multiple dimensions based on the heat transfer efficiency of the temperature probe, and uses effective data to obtain calibration evaluation results.

[0008] This method allows for precise and effective calibration and evaluation of different types of igniters and gas types. The established standardized calibration process simplifies the calibration operation for test personnel, reducing or even eliminating the influence of test personnel's experience.

[0009] According to one specific embodiment of the present invention, the calibration system provides at least one arc-shaped guide member, which is arranged to allow the thermocouple wire connecting the thermometer and the temperature probe to bypass; wherein, in step (2), the direction of the arc-shaped guide member is finely adjusted to make the thermocouple wire turn smoothly and avoid the thermocouple wire being broken.

[0010] According to a specific embodiment of the present invention, in step (2), the distance between the temperature probe and the top of the igniter in the height direction is set to not exceed half of the flame height; wherein, the flame height of the igniter is set to ≤200mm.

[0011] According to a specific embodiment of the present invention, in step (3), the fluctuation range of the calibration starting temperature T1 is ±2℃, and the fluctuation range of the calibration ending temperature T2 is ±3℃.

[0012] According to a specific embodiment of the present invention, the gas type in step (3) includes methane, propane, and butane; the process in step (7) of determining whether the flame temperature of the igniter meets the requirements based on the gas type is as follows: If the flame heating time ∆t exceeds ±2s of the set value, it is judged as unqualified; When the flame heating time ∆t does not exceed ±2s of the set value, the calculated heat transfer efficiency η of the temperature probe is compared with the set value. Based on the comparison result, it is determined whether the flame temperature of the igniter meets the requirements. Specifically: when the gas is methane, if the heat transfer efficiency η of the temperature probe exceeds 15% ±0.7%, the calibration is deemed unqualified; when the gas is propane, if the heat transfer efficiency η of the temperature probe exceeds 18.3% ±1%, the calibration is deemed unqualified; when the gas is butane, if the heat transfer efficiency η of the temperature probe exceeds 19.4% ±1.1%, the calibration is deemed unqualified.

[0013] According to a specific embodiment of the present invention, before step (6), calibration is performed three or more times consecutively, and the average value of the results of the three or more calibrations is taken. The heating time of the flame and the effective heat absorption power of the temperature probe during the ignition test are calculated based on the average value of the results.

[0014] Furthermore, during continuous calibration, in step (5), the temperature probe needs to be cooled to below 50°C before proceeding with the subsequent calibration process.

[0015] To more clearly illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0016] Figure 1 This is an exemplary diagram illustrating the use of the calibration system; Figure 2 yes Figure 1 Side view of the calibration system; Figure 3 yes Figure 1 First perspective view of the support tool; Figure 4 yes Figure 1 Second perspective view of the support tool; Figure 5 This is a schematic diagram of the thermocouple wire passing around the arc-shaped guide member; Figure 6 This is an enlarged schematic diagram showing the guide hole in the horizontal support component. Detailed Implementation

[0017] To better understand the above-mentioned objects, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description with reference to embodiments in order to provide a thorough understanding of the present invention; however, it should be understood that the following embodiments and detailed descriptions are for illustrative purposes only and do not limit the scope of protection of the present invention.

[0018] The embodiment discloses a method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test, including the following steps: (1) Ignite the igniter for the first time, adjust the pressure and flow of the igniter to generate a small flame for the ignition test, and extinguish the igniter after the flame height of the igniter is adjusted. Before the ignition test, a suitable small flame is modulated based on current standards and specifications to determine the flame height of the igniter, providing a stable basis for subsequent temperature calibration. In this embodiment, the small flame is typically generated by a single-tube igniter with a tube diameter ≤50mm. The process of adjusting the flame height of the igniter during the initial ignition also incorporates existing visual inspection methods to assess the flame condition, better aligning with current standards and specifications and providing effective conditions for subsequent ignition tests.

[0019] (2) Move the temperature probe of the calibration system horizontally so that the temperature probe is directly above the flame generated by the igniter, and move the temperature probe vertically so that the temperature probe and the top of the igniter are at the corresponding height positions; wherein, the flame height of the igniter is set to ≤200mm. Preferably, the distance between the temperature probe and the top of the igniter in the height direction is set to no more than half of the flame height. This is beneficial to ensure the temperature receiving area of ​​the temperature probe and also to the temperature probe to measure the flame temperature more accurately.

[0020] The calibration system used in the embodiments is as follows: Figure 1-2 As shown, the calibration system includes a thermometer 10, an igniter 20, a temperature probe 30, and a support tool 40. The temperature probe 30 is connected to the thermometer 10 via a thermocouple wire 50, and the support tool 40 is used to guide and support the thermocouple wire 50.

[0021] The temperature measuring instrument 10 preferably has a range of 0~2500°C and an accuracy of ±0.1°C. The temperature measuring instrument 10 can be a commercially available product, which can be connected to the computer 60 via an RS485 interface to transmit the collected flame temperature data to the computer 60 for display and processing analysis.

[0022] Thermocouple wire 50 is relatively thin, generally less than 1 mm in diameter. While this size and specification of thermocouple wire 50 possesses elastic strength (ductility), it frequently breaks or is damaged during the actual fixing process. To reduce the occurrence of breakage, the thermocouple wire 50 in this embodiment preferably uses a mineral-insulated metal-clad fine-wire thermocouple with insulating nodes, and the operating temperature of the metal sheath is ≥1100°C.

[0023] Temperature probe 30 is specifically a metal probe, and preferably its structure includes upper and lower parts (see...). Figure 1 The upper part near the thermocouple is cylindrical, and the lower part near the flame is frustum-shaped. This structure helps to increase the contact area between the temperature probe 30 and the flame.

[0024] like Figure 3-4 As shown, the support tool 40 includes a main support 41, a horizontal support member 42, a vertical support member 43, and an arc-shaped guide member 44. To reduce the overall weight, the main support 41, the horizontal support member 42, and the vertical support member 43 are preferably made of plastic. In some other embodiments, the main support 41, the horizontal support member 42, and the vertical support member 43 may also be made of metal, such as aluminum profiles.

[0025] Please continue reading. Figure 3 The main support 41 is provided with a first vertical mounting groove 411 and a second vertical mounting groove 412. The proximal end of the horizontal support member 42 is hinged to the first vertical mounting groove 411 by bolts. The first vertical mounting groove 411 is specifically an elongated groove. The height of the horizontal support member 42 can be adjusted by changing the position of the hinge point. The distal end of the horizontal support member 42 is provided with a guide hole 421 for the thermocouple wire 50 to pass through.

[0026] The lower end of the vertical support member 43 is connected to the second vertical mounting groove 412 via a locking member 45. An arc-shaped guide member 44 is mounted on the vertical support member 43 and located above the horizontal support member 42. The second vertical mounting groove 412 is preferably an elongated groove. The height of the arc-shaped guide member 44 is changed by altering the locking position of the locking member 45, thus adapting to different types of igniters 20. To maintain effective locking, there can be two or more locking members 45.

[0027] In this embodiment, the thermocouple wire 50 is led out from the temperature measuring instrument 10, passes through the left side of the main support 41, goes upward around the arc-shaped guide member 44, and is conducted to the right side of the main support 41. Then it is guided downward through the guide hole 421 on the horizontal support member 42 to suspend the temperature probe 30 directly above the flame generated by the igniter 20. The thin and soft thermocouple wire 50 is arranged in the above manner, which can achieve effective fixation and conduction adjustment. The connection and conduction of the thermocouple wire 50 are smoother, and the positional stability of the temperature probe 30 is better. It is especially suitable for the igniter 20 device with limited internal space.

[0028] To further prevent the thermocouple wire 50 from breaking, an arc-shaped guide member 44 is provided in this embodiment for transmission guidance, and at the same time, the conduction direction of the thermocouple wire 50 is finely adjusted. As a preferred structure of the arc-shaped guide member 44, such as... Figure 5 As shown, the arc-shaped guide member 44 includes an arc-shaped body 441 and a locking bolt 442. The arc-shaped body 441 is provided with an arc-shaped groove 443 for the thermocouple wire 50 to pass through. The arc-shaped body 441 is connected to the vertical support member 43 by the locking bolt 442. When the locking bolt 442 is not locked, the arc-shaped body 441 can be rotated to adjust the turning angle of the thermocouple wire 50.

[0029] Please continue reading. Figure 5 The arc-shaped guide member 44 further includes a clamping bolt 444, which is connected to the arc-shaped body 441 and located above the thermocouple wire 50. The clamping bolt 444 is used to guide and limit the thermocouple wire 50. Preferably, the arc-shaped guide member 44 also includes heat insulation cotton 445, which is laid in the arc-shaped groove 443 to achieve heat insulation at the contact point.

[0030] Please combine Figure 1 and Figure 3-4 The main support 41 is equipped with an inclined support rod 46, which provides support to the horizontal support member 42, forming a triangular support structure between the main support 41, the horizontal support member 42, and the inclined support rod 46. Specifically, a horizontal mounting groove 422 for connection is provided in the middle of the horizontal support member 42. One end of the inclined support rod 46 is located below the horizontal support member 42 and is hinged to the main support 41. The other end of the inclined support rod 46 is hinged to the horizontal mounting groove 422 by a connecting bolt.

[0031] like Figure 6As shown, a V-shaped guide portion 421a is provided on the guide hole 421, and a stop pin 423 corresponding to the V-shaped guide portion 421a is provided on the horizontal support member 42. The thermocouple wire 50 is limited by the cooperation between the V-shaped guide portion 421a and the stop pin 423. In an optional embodiment, a heat insulation pad is also provided at the position where the V-shaped guide portion 421a contacts the thermocouple wire 50.

[0032] Please refer to it again. Figure 1 and Figure 3-4 The support tool 40 may further include a fixed support member 47, the structure of which is preferably the same as or similar to that of the horizontal support member 42; wherein, the fixed support member 47 is horizontally arranged on the main support 41 and located above the horizontal support member 42. In this embodiment, by utilizing the fixed support member 47 and the horizontal support member 42 to form a vertical effect of the thermocouple wire 50, it is beneficial to adjust the position of the temperature probe 30 at the end of the thermocouple wire 50.

[0033] (3) Enter calibration information into the computer 60 of the calibration system and set the calibration start temperature T1 and calibration end temperature T2; wherein, the calibration information includes flame height, gas type and gas flow rate. More preferably, the calibration information may also include information required for the test, such as calibration number and calibration date, which may be added or deleted as needed.

[0034] It should be noted that the flame temperature change during the ignition test is instantaneous and extremely rapid. To ensure the stability of the test process, the calibration start temperature T1 and calibration end temperature T2 have a certain fluctuation range, and the fluctuation range of the calibration end temperature T2 is relatively larger as the temperature rises. For example, the fluctuation range of the calibration start temperature T1 is ±2℃, and the calibration system automatically generates the corresponding temperature range interval, i.e., [T11, T12], where T11 = (T1-2)℃ and T12 = (T1+2)℃. Similarly, the fluctuation range of the calibration end temperature T2 is ±3℃, and the calibration system automatically generates the corresponding temperature range interval, i.e., [T21, T22], where T21 = (T2-3)℃ and T22 = (T2+3)℃. By providing the fluctuation range value, the flame temperature value is collected in real time by the temperature probe, which is beneficial for capturing the flame temperature value in a one-time, uniform, relatively stable and accurate manner.

[0035] (4) Ignite the igniter again and automatically collect the flame temperature data through the thermometer connected to the temperature probe in the calibration system. When the flame temperature reaches the calibration start temperature T1, the timing module in the calibration system starts timing to obtain time t1. When the flame temperature reaches the calibration end temperature T2, the timing module in the calibration system starts timing to obtain time t2.

[0036] For accurate recording, the timing module is preferably set to a range of ≥600s and an accuracy of ±0.01s; the thermometer is preferably set to a range of 0~2500°C and an accuracy of ±0.1°C.

[0037] (5) Extinguish the igniter and cool down the temperature probe; (6) Record and calculate the flame heating time and the effective heat absorption power of the temperature probe during the ignition test; Wherein, the flame heating time ∆t is the time it takes for the flame temperature to rise from the calibration start temperature T1 to the calibration end temperature T2, that is, ∆t=t2-t1; The effective heat absorption power P of the temperature probe 有效 =m*c*∆T / ∆t, where: m is the mass of the temperature probe, c is the specific heat capacity of the temperature probe, and ∆T is the temperature difference between the calibration endpoint temperature T2 and the calibration starting temperature T1; Preferably, calibration is performed three or more times before step (6), and the average value of the results of the three or more calibrations is taken. The heating time of the flame and the effective heat absorption power of the temperature probe during the ignition test are calculated based on the average value of the results. In particular, during continuous calibration, the temperature probe needs to be cooled to below 50°C in step (5) before the subsequent calibration process, which helps to improve the accuracy of the calibration.

[0038] (7) Based on the obtained flame heating time ∆t and the effective absorbed heat power P of the temperature probe 有效 Combined with the theoretical thermal power P of the gas 理论 =Flow rate × Calorific value of gas, calculate the heat transfer efficiency η of the temperature probe η=P 有效 / P 理论 This determines whether the flame temperature of the igniter meets the requirements.

[0039] The types of gas used in step (3) include methane, propane, and butane; more specifically, step (7) can determine whether the flame temperature of the igniter meets the requirements based on the type of gas used: If the flame heating time ∆t exceeds ±2s of the set value, it is judged as unqualified; When the flame heating time ∆t does not exceed ±2s of the set value, the calculated heat transfer efficiency η of the temperature probe is compared with the set value. Based on the comparison result, it is determined whether the flame temperature of the igniter meets the requirements, that is: 1) When the fuel gas is methane, if the heat transfer efficiency η of the temperature probe exceeds 15%±0.7%, the calibration is deemed unqualified. 2) If the heat transfer efficiency η of the temperature probe exceeds 18.3%±1% when the fuel gas is propane, the calibration is deemed unqualified. 3) If the heat transfer efficiency η of the temperature probe exceeds 19.4%±1.1% when the fuel gas is butane, the calibration is deemed unqualified.

[0040] The embodiments can perform accurate and effective calibration and evaluation for different types of igniters and gas types. The established standardized calibration process makes the calibration operation of test personnel simpler, reduces or even eliminates the influence of the test personnel's experience factors, effectively ensures the validity of temperature data during the test, thereby improving the test results. Furthermore, by using multi-dimensional data for comprehensive judgment, the calibration evaluation results can be obtained using effective data forms, which is more reliable.

[0041] Although the present invention has been described above by way of embodiments, the above embodiments are only used to exemplify possible implementations of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or changes made by those skilled in the art in accordance with the present invention should also be covered by the scope of protection defined by the claims of the present invention.

Claims

1. A method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test, characterized in that, Includes the following steps: (1) Ignite the igniter for the first time, adjust the pressure and flow of the igniter to generate a small flame for the ignition test, and extinguish the igniter after the flame height of the igniter is adjusted. (2) Move the temperature probe of the calibration system horizontally so that the temperature probe is directly above the flame produced by the igniter, and move the temperature probe vertically so that the top of the temperature probe and the igniter are at the corresponding height positions. (3) Enter calibration information into the calibration system and set the calibration start temperature T1 and calibration end temperature T2; wherein, the calibration information includes flame height, gas type and gas flow rate; (4) Ignite the igniter again and automatically collect flame temperature data through the thermometer connected to the temperature probe in the calibration system. When the flame temperature reaches the calibration start temperature T1, the timing module in the calibration system starts timing to obtain time t1. When the flame temperature reaches the calibration end temperature T2, the timing module in the calibration system starts timing to obtain time t2. (5) Extinguish the igniter and cool down the temperature probe; (6) Record and calculate the flame heating time and the effective heat absorption power of the temperature probe during the ignition test; Wherein, the flame heating time ∆t is the time it takes for the flame temperature to rise from the calibration start temperature T1 to the calibration end temperature T2, that is, ∆t=t2-t1; Effective absorbed thermal power P of the temperature probe 有效 = m * c * ΔT / Δt, where m is the mass of the temperature probe, c is the specific heat capacity of the temperature probe, and ΔT is the temperature difference between the calibration end temperature T2 and the calibration start temperature T1. (7) According to the obtained temperature rising time Δt of the flame and the effective absorbed heat power P of the temperature probe 有效 , the heat transfer efficiency η of the temperature probe is calculated by combining the theoretical heat power P of the gas 理论 =P 有效 ×heat value of the gas, and the heat transfer efficiency η=P 理论 , to determine whether the flame temperature of the igniter meets the requirements.

2. The method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test according to claim 1, characterized in that: The calibration system provides at least one arc-shaped guide member, which is arranged to allow the thermocouple wire connecting the thermometer and the temperature probe to bend around it; wherein, in step (2), the direction of the arc-shaped guide member is finely adjusted to make the thermocouple wire turn smoothly and avoid the thermocouple wire being broken.

3. The method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test according to claim 1, characterized in that: In step (2), the distance between the temperature probe and the top of the igniter in the height direction is set to no more than half the flame height; wherein, the flame height of the igniter is set to ≤200mm.

4. The method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test according to claim 1, characterized in that: In step (3), the starting temperature T1 of the calibration fluctuates within ±2℃, and the ending temperature T2 of the calibration fluctuates within ±3℃.

5. The method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test according to claim 1, characterized in that: The types of fuel gas used in step (3) include methane, propane, and butane; The process in step (7) of determining whether the flame temperature of the igniter meets the requirements based on the type of gas is as follows: If the flame heating time ∆t exceeds ±2s of the set value, it is judged as unqualified; When the flame heating time ∆t does not exceed ±2s of the set value, the calculated heat transfer efficiency η of the temperature probe is compared with the set value. Based on the comparison result, it is determined whether the flame temperature of the igniter meets the requirements. Specifically: when the gas is methane, if the heat transfer efficiency η of the temperature probe exceeds 15% ±0.7%, the calibration is deemed unqualified; when the gas is propane, if the heat transfer efficiency η of the temperature probe exceeds 18.3% ±1%, the calibration is deemed unqualified; when the gas is butane, if the heat transfer efficiency η of the temperature probe exceeds 19.4% ±1.1%, the calibration is deemed unqualified.

6. The method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test according to claim 1, characterized in that: Before step (6), perform calibration three or more times consecutively, and take the average value of the results of the three or more calibrations. Calculate the flame heating time and the effective absorbed heat power of the temperature probe during the ignition test based on the average value of the results.

7. The method for calibrating and evaluating the small flame temperature of an igniter based on an ignition test according to claim 6, characterized in that: During continuous calibration, in step (5), the temperature probe needs to be cooled to below 50°C before proceeding with the subsequent calibration process.

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