阅读说明：本技术 一种电热管热能转换效率测试方法 (Method for testing heat energy conversion efficiency of electric heating tube ) 是由 周衍增 李新喜 张勇健 于 2021-09-15 设计创作，主要内容包括：一种电热管热能转换效率测试方法,属于电热管检测技术领域。其特征在于：包括如下步骤：测量电热管(3)的重量；在电热管(3)两端输入电压,同时对电热管(3)上多个测温点的温度进行检测；调整输入电压,使电热管(3)上温度最高的测温点的温度稳定在测试温度,并记录此时的输入功率；计算电热管的热能转换参数,热能转换参数为电热管(3)的输入功率与重量的比值；通过热能转换参数对电热管(3)进行评价,热能转换参数小于0.7则电热管(3)合格,且热能转换参数越小,电热管(3)的热能转换效率越高。本发明能够准确检测出电热管的热能转换效率,并衡量电热管的使用寿命,方便对电热管进行准确的检测,检测方便。(A method for testing heat energy conversion efficiency of an electric heating tube belongs to the technical field of electric heating tube detection. The method is characterized in that: the method comprises the following steps: measuring the weight of the electric heating tube (3); voltage is input at two ends of the electric heating tube (3), and the temperature of a plurality of temperature measuring points on the electric heating tube (3) is detected simultaneously; adjusting the input voltage to stabilize the temperature of the temperature measuring point with the highest temperature on the electric heating tube (3) at the test temperature, and recording the input power at the moment; calculating heat energy conversion parameters of the electric heating tube, wherein the heat energy conversion parameters are the ratio of the input power to the weight of the electric heating tube (3); the electric heating tube (3) is evaluated through the heat energy conversion parameter, the electric heating tube (3) is qualified if the heat energy conversion parameter is less than 0.7, and the smaller the heat energy conversion parameter is, the higher the heat energy conversion efficiency of the electric heating tube (3) is. The invention can accurately detect the heat energy conversion efficiency of the electric heating tube, measure the service life of the electric heating tube, and facilitate accurate detection of the electric heating tube.)

1. A method for testing the heat energy conversion efficiency of an electric heating tube is characterized by comprising the following steps: the method comprises the following steps:

measuring the weight of the electric heating tube (3);

voltage is input at two ends of the electric heating tube (3), and the temperature of a plurality of temperature measuring points on the electric heating tube (3) is detected simultaneously;

adjusting the input voltage to stabilize the temperature of the temperature measuring point with the highest temperature on the electric heating tube (3) at the test temperature, and recording the input power at the moment;

calculating heat energy conversion parameters of the electric heating tube, wherein the heat energy conversion parameters are the ratio of the input power to the weight of the electric heating tube (3);

the electric heating tube (3) is evaluated through the heat energy conversion parameter, the electric heating tube (3) is qualified if the heat energy conversion parameter is less than 0.7, and the smaller the heat energy conversion parameter is, the higher the heat energy conversion efficiency of the electric heating tube (3) is.

2. The method for testing thermal energy conversion efficiency of an electrical heated tube according to claim 1, wherein: and the weight of the electric heating tube (3) is measured by adopting an electronic scale.

3. The method for testing thermal energy conversion efficiency of an electrical heated tube according to claim 1, wherein: the test temperature was 300 ℃.

4. The method for testing thermal energy conversion efficiency of an electrical heated tube according to claim 1, wherein: and the temperatures of five temperature measuring points on the electric heating tube (3) are detected, and the five temperature measuring points are uniformly distributed at intervals along the electric heating tube (3).

5. The method for testing thermal energy conversion efficiency of an electrothermal tube according to claim 1 or 4, wherein: the electric heating tube (3) is placed on the heat insulation plate (2), and the temperature of the temperature measuring point of the electric heating tube (3) is detected through the temperature probe (4).

6. The method for testing thermal energy conversion efficiency of an electrical heated tube according to claim 5, wherein: the heat insulation board (2) is rock wool, a placing board (1) is arranged at the bottom of the heat insulation board (2), and the thickness of the heat insulation board (2) is 10 mm.

7. The method for testing thermal energy conversion efficiency of an electrical heated tube according to claim 1, wherein: the method also comprises the step of designing the shape of the electric heating tube (3) according to the heat energy conversion parameters to ensure that the section of the electric heating tube (3) is gradually narrowed from top to bottom.

8. The method for testing thermal energy conversion efficiency of an electrical heated tube according to claim 7, wherein: the top of the electric heating tube (3) is horizontally arranged, and the bottom is in the shape of a circular arc with a convex middle part.

Technical Field

A method for testing heat energy conversion efficiency of an electric heating tube belongs to the technical field of electric heating tube detection.

Background

The electric heating pot is a modern cooker capable of being processed by frying, steaming, boiling, rinsing, stewing and the like. The multifunctional cooking machine can cook food, can preserve heat, is clean and sanitary in use, has no radiation, saves time and labor, and is one of indispensable tools for modernization of housework. The electric heating pot usually realizes heating through an electric heating pipe and a soaking plate at the bottom, so the quality of the electric heating pipe directly influences the use of the electric heating pot. The requirement of the electric heating tube at present is that the breakdown voltage of the electric heating tube is higher than 3000V, and the service life of the electric heating tube is longer than 3000h, because the service life of the electric heating tube is longer, the detection of the electric heating tube at present only can detect the breakdown voltage, but cannot detect the thermal efficiency and the service life of the electric heating tube. Due to the above problems, the quality of the electric heating tube is uneven, and the thermal efficiency of the electric heating tube cannot be evaluated.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method can detect the heat energy conversion efficiency of the electric heating tube, determine the service life of the electric heating tube according to the heat energy conversion efficiency, and is accurate and convenient in detection.

The technical scheme adopted by the invention for solving the technical problems is as follows: the method for testing the heat energy conversion efficiency of the electric heating tube is characterized in that: the method comprises the following steps:

measuring the weight of the electric heating tube;

inputting voltage at two ends of the electric heating tube, and detecting the temperature of a plurality of temperature measuring points on the electric heating tube;

adjusting the input voltage to stabilize the temperature of the temperature measuring point with the highest temperature on the electric heating tube at the testing temperature, and recording the input power at the moment;

calculating a heat energy conversion parameter of the electric heating tube, wherein the heat energy conversion parameter is the ratio of the input power and the weight of the electric heating tube;

the electric heating tube is evaluated through the heat energy conversion parameters, the electric heating tube is qualified if the heat energy conversion parameters are less than 0.7, and the smaller the heat energy conversion parameters, the higher the heat energy conversion efficiency of the electric heating tube is.

Preferably, the weight of the electrothermal tube is measured by using an electronic scale. The weight of the electric heating tube is measured through the electronic scale, the measurement is convenient, and the measurement is accurate.

Preferably, the test temperature is 300 ℃. The testing temperature is 300 ℃, so that the detection accuracy can be ensured, the influence of the environmental temperature on the detection can be reduced, and the detection structure is more accurate.

Preferably, the temperature of five temperature measuring points on the electric heating tube is detected, and the five temperature measuring points are uniformly distributed at intervals along the electric heating tube. The five temperature detection points are arranged on the electric heating tube, so that the temperature of the electric heating tube can be comprehensively detected, the highest temperature measurement point on the electric heating tube can be accurately judged, and the temperature of the highest temperature measurement point of the electric heating tube can be accurately detected when different electric heating tubes are detected.

Preferably, the electric heating tube is placed on the heat insulation plate, and the temperature of the temperature measuring point of the electric heating tube is detected through the temperature probe. The electrothermal tube is placed on the heat insulation plate, so that the influence of the external environment on the detection of the electrothermal tube is eliminated, the temperature of the temperature measuring point of the electrothermal tube is detected by the temperature probe, and the temperature detection of the electrothermal tube is accurate.

Preferably, the heat insulating board be rock wool, the bottom of heat insulating board is provided with places the board, and the thickness of heat insulating board is 10 mm. The thickness of the heat insulation plate is 10mm, so that the heat generated by the electric heating tube can be prevented from being transferred downwards.

Preferably, the method further comprises designing the shape of the electrical heating tube according to the thermal energy conversion parameter, so that the cross section of the electrical heating tube is gradually narrowed from top to bottom. The section of the electric heating tube is gradually narrowed from top to bottom, so that the reasonable thickness of the magnesium oxide powder is ensured, the electric insulation performance of the electric heating tube can be ensured, and the heat energy conversion efficiency of the electric heating tube can be ensured.

Preferably, the top of the electric heating tube is horizontally arranged, and the bottom of the electric heating tube is in the shape of a circular arc with a downward convex middle part. The electric heating cooker has the advantages that the large contact area between the electric heating tube and the soaking disc can be ensured, heat emitted by the electric heating tube can be quickly transmitted to the soaking disc, the heat efficiency of the electric heating cooker is high, the electric heating tube is conveniently welded with the soaking disc, the working surface of the electric heating tube is in contact with the soaking disc in the largest area, the bottom of the electric heating tube is coaxial with the electric heating wire, and the breakdown resistance of the electric heating tube can be improved.

The electric energy is converted into the parameter value of the heat energy in the working process of the electric heating tube, which is an important parameter for reflecting the quality and the service life of the electric heating tube, magnesium oxide powder is filled and compacted between the heating wire of the electric heating tube and the inner wall of the electric heating tube, so that the electric insulation and the heat conduction between the heating wire and the tube wall are realized, under a certain insulation strength, the smaller the thermal resistance of the magnesium oxide powder is, the better the heat conduction effect of the electric heating tube is, the smaller the temperature difference between the heating wire and the tube wall is, the longer the service life of the electric heating tube is, and the higher the heat energy conversion efficiency of the electric heating tube is.

Under the condition that the pipe diameter and the length of the electric heating pipe are fixed, the larger the thickness of the magnesium oxide powder in the electric heating pipe is, the better the electric insulation performance of the electric heating pipe is, the larger the temperature difference between the electric heating wire and the pipe wall of the electric heating pipe is, the lower the heat energy conversion efficiency of the electric heating pipe is, and the shorter the service life of the electric heating pipe is; the smaller the thickness of the magnesia powder in the electric heating tube is, the smaller the temperature difference between the electric heating wire and the tube wall of the electric heating tube is, the higher the heat energy conversion efficiency of the electric heating tube is, the longer the service life of the electric heating tube is, but the poorer the electrical insulation performance of the electric heating tube is. At present, no parameter can balance the contradiction, the inventor tests the heat energy conversion efficiency of the electric heating tube by defining a heat energy conversion parameter, namely the ratio of the input power and the weight of the electric heating tube, taking the magnesium oxide powder and the input power as the detected quantity, and detects the service life of the electric heating tube by the temperature difference between the electric heating wire and the inner wall of the electric heating tube, thereby accurately realizing the detection of the heat energy conversion efficiency and the service life of the electric heating tube.

Compared with the prior art, the invention has the beneficial effects that:

the method for testing the heat energy conversion efficiency of the electric heating tube measures the temperature of the electric heating tube, namely the temperature of the wall of the electric heating tube, can measure the temperature of the heating wire in the electric heating tube by inputting power, so that the wall temperature of the electric heating tube reaches the test temperature, can judge the heat conversion efficiency of the electric heating tube by comparing the temperature of the heating wire of the electric heating tube, and can measure the service life of the electric heating tube according to the temperature difference between the heating wire and the wall, and the heat energy conversion parameter comprehensively evaluates the weight of the electric heating tube by the input power of the heating wire, thereby accurately detecting the heat energy conversion efficiency of the electric heating tube, measuring the service life of the electric heating tube, facilitating the accurate detection of the electric heating tube and facilitating the detection.

Drawings

FIG. 1 is a perspective view of an electrothermal tube detection device.

Fig. 2 is a perspective view of the electric heating tube.

Fig. 3 is a schematic sectional view of the electric heating tube.

In the figure: 1. the device comprises a placing plate 2, a heat insulation plate 3, an electric heating tube 4, a temperature probe 5, magnesium oxide powder 6 and an electric heating wire.

Detailed Description

FIGS. 1 to 3 illustrate preferred embodiments of the present invention, and the present invention will be further described with reference to FIGS. 1 to 3.

The present invention is further described with reference to the following detailed description, however, it should be understood by those skilled in the art that the detailed description given herein with respect to the accompanying drawings is for better explanation and that the present invention is not necessarily limited to the specific embodiments, but rather, for equivalent alternatives or common approaches, may be omitted from the detailed description, while still remaining within the scope of the present application.

As shown in fig. 1: the device for testing the heat energy conversion efficiency of the electric heating tube comprises a placing plate 1, a heat insulation plate 2, a temperature probe 4, a power meter, a voltmeter and a voltage regulator. Wherein place board 1 and be the metal sheet, place board 1 and be square, the thickness of placing board 1 is 2mm, and heat insulating board 2 sets up the upside of placing board 1, and heat insulating board 2 is the rock wool, and heat insulating board 2 also is square, and the length of a side of heat insulating board 2 is less than the length of a side of placing board 1, and the thickness of heat insulating board 2 is 10 mm.

The electrothermal tube 3 to be detected is placed on the heat insulation board 2, and the whole electrothermal tube 3 is positioned right above the heat insulation board 2. The temperature of the temperature measuring points of the electric heating tube 3 is detected by the temperature probes 4, in this embodiment, five temperature measuring points are uniformly distributed along the electric heating tube 3 at intervals, each temperature measuring point is provided with one temperature probe 4, and the temperatures of the five temperature measuring points of the electric heating tube 3 are simultaneously detected by the temperature probes 4.

The input end of the voltage regulator is connected with alternating current, the output end of the voltage regulator is connected with two ends of the electric heating tube 3, the power meter and the voltmeter are connected with the electric heating tube 3, and input voltage and input power of the electric heating tube are detected.

A method for testing the heat energy conversion efficiency of an electric heating tube comprises the following steps:

the weight of the electric heating tube 3 is measured.

The weight of the electrothermal tube is measured by an electronic scale.

Voltage is input to two ends of the electric heating tube 3, and the temperature of a plurality of temperature measuring points on the electric heating tube 3 is detected.

The voltage is input to the two ends of the electric heating tube 3 through the voltage regulator, and the temperature of five temperature measuring points on the electric heating tube 3 is measured simultaneously through the temperature probe 4.

The input voltage is adjusted to stabilize the temperature of the temperature measuring point with the highest temperature on the electric heating tube 3 at the testing temperature, and the input power at the moment is recorded.

The input voltage of the electric heating tube 3 is adjusted by the voltage regulator until the temperature of the temperature measuring point with the highest temperature on the electric heating tube 3 is stabilized at the testing temperature, which is 300 ℃ in the embodiment. When the temperature of the temperature measuring points of the electric heating tube 3 is detected, five temperature measuring points are arranged, so that the temperature of the electric heating tube 3 can be comprehensively measured to determine the highest point of temperature. When the temperature of the highest point of the temperature is stabilized at 300 ℃, the testing requirement is met, and the power on the power meter, namely the input power of the electrothermal tube 3, is recorded at the moment.

And calculating the heat energy conversion parameter of the electric heating tube, wherein the heat energy conversion parameter is the ratio of the input power to the weight of the electric heating tube 3.

The calculation formula of the thermal energy conversion parameter K is as follows,

K=P/G；

wherein, P is the input power of the electrothermal tube 3, and the unit is w; g is the weight of the electrothermal tube 3 and is G.

The electric heating tube 3 is evaluated through the heat energy conversion parameter, if the heat energy conversion parameter is less than 0.7, the electric heating tube 3 is qualified, and the smaller the heat energy conversion parameter is, the higher the heat energy conversion efficiency of the electric heating tube 3 is.

The weight side detection of the electrothermal tube 3 can be performed before the temperature detection of the temperature measuring point and the input power detection, and can also be performed after the temperature detection of the temperature measuring point and the power detection.

As shown in FIGS. 2 to 3: the method for testing the heat energy conversion efficiency of the electric heating tube also comprises the step of gradually narrowing the section of the electric heating tube 3 from top to bottom according to the shape design of the electric heating tube 3 according to the heat energy conversion parameters.

The electric heating tube 3 is encircled into a ring shape, the end part of the electric heating tube 3 is bent downwards, so that the interference on the welding between the electric heating tube 3 and the soaking plate can be avoided, the wiring of the electric heating tube 3 is facilitated, and the electric heating tube 3 is an aluminum tube. The electric heating wire 6 is arranged in the electric heating tube 3, the electric heating tube 3 is filled with magnesia powder 5, and the magnesia powder 5 has good heat conductivity and good insulating property.

The top of the electric heating tube 3 is horizontal, both sides of the top of the electric heating tube 3 are inclined from top to bottom inwards gradually, so that the middle of the electric heating tube 3 is in a cone shape which is gradually narrowed from top to bottom, the bottom of the electric heating tube 3 is in a circular arc shape with a convex middle part, both sides of the bottom of the electric heating tube 3 are tangent to the corresponding sides of the middle part respectively, and the electric heating wire 6 is coaxially arranged with the bottom of the electric heating tube 3.

According to the heat energy conversion parameter, the smaller the temperature difference between the electric heating wire 6 and the wall of the electric heating tube 3 is, the smaller the heat energy conversion parameter is, the longer the service life of the electric heating wire 6 is, and the higher the heat energy conversion efficiency is, so that when the electric heating tube 3 is designed, the heat transferred to the electric heating tube 3 by the electric heating wire 6 is rapidly transferred, and meanwhile, the reasonable thickness of the magnesium oxide powder 5 is ensured, and the electrical insulation performance of the electric heating tube 3 is ensured.

The following table shows the test data of different specifications of electrothermal tubes:

。

the inventor conducts 220V alternating current to 13 groups of electric heating tubes 3 in the upper table respectively and conducts life detection, wherein 1-11 groups of corresponding electric heating tubes 3 still work stably after being continuously conducted for 3000 hours, and the life of 12 groups of corresponding electric heating tubes 3 is far less than 3000 hours. The electrothermal tubes corresponding to the 11 th group in the above table are the electrothermal tubes 3 with the cross-sectional shape determined in this embodiment.

Through the experiment, under the condition that the model of the electric heating tube 3 is certain, when the heat energy conversion parameter is less than 0.7, the input power is small, the temperature difference between the tube wall of the electric heating tube 3 and the electric heating wire 6 is small, the heat energy conversion efficiency of the electric heating tube 3 is high, and the service life of the electric heating wire 6 is long, namely the service life of the electric heating tube 3. Under the condition that the model of the electric heating tube 3 is fixed, when the heat energy conversion parameter is larger than 0.7, namely the amount of the magnesium oxide powder in the electric heating tube 3 is large, the speed of transferring the heat of the electric heating wire 6 to the electric heating tube 3 is low, namely the temperature difference between the electric heating wire 6 and the tube wall of the electric heating tube 3 is large, at the moment, the heat energy conversion efficiency of the electric heating tube 3 is low, the electric heating wire 6 is easy to burn off, the service life of the electric heating wire 6 is short, namely the service life of the electric heating tube 3 is short.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.