Testing method of electric heater

Abstract

The invention discloses a method for testing an electric heater, and the method comprises the steps: introducing gas into a flow channel cavity of the electric heater, starting the electric heater, and enabling a heating element of the electric heater to emit heat so as to heat the gas introduced into the flow channel cavity. According to the technical scheme of the invention, a water-through and power-on inspection mode can be changed into a gas-through and power-on inspection mode, water resources do not need to be wasted in the product testing process, water spots cannot be generated after detection, the product inspection efficiency is greatly improved while the purpose of product inspection is met, and thus the production takt is improved.

Description

Technical Field

[0001] The present application relates to the field of electric heaters, and more specifically, to a testing method for detecting the performance of electric heaters. Background Art

[0002] At present, electric heaters are widely used in various places, such as in the field of new energy vehicles, in the field of distributed energy heating, etc. During the production process, electric heaters need to be inspected and tested to verify whether they meet the design expectations and meet the factory standards.

[0003] In the traditional inspection test, it is necessary to flow liquid (such as water) into the flow channel cavity of the electric heater and measure the heating power. The electric heating is judged to be qualified by checking the change of water temperature and the temperature of the electric heater itself. However, after the test is completed, it is necessary to introduce gas again to dry the internal liquid to prevent the liquid from being retained inside the electric heater and causing damage to the device. This traditional height inspection test scheme can refer to the Chinese invention patent CN 216284335 U previously proposed by the applicant of this application. Summary of the invention

[0004] Through continuous scientific research, this application breaks the technical bias in traditional inspection and testing methods and proposes a new inspection and testing solution, which not only improves work efficiency but also reduces testing costs.

[0005] According to the present application, a testing method for an electric heater is proposed, which includes: introducing gas into a flow channel cavity of the electric heater, starting the electric heater, and causing a heating element of the electric heater to generate heat to heat the gas introduced into the flow channel cavity.

[0006] Preferably, the testing method does not involve introducing any liquid into the flow channel cavity.

[0007] Preferably, the gas introduced into the flow channel cavity has predetermined parameters, which include at least one of pressure, flow rate and temperature.

[0008] Further preferably, the testing method comprises:

[0009] The parameter of the gas flowing into the inlet of the flow channel cavity is monitored, and the parameter of the gas flowing out of the outlet of the flow channel cavity is monitored.

[0010] Preferably, after a stable airflow is established in the flow channel cavity, the electric heater is started to heat the heating element of the electric heater to heat the gas passing into the flow channel cavity.

[0011] Further preferably, the heating element is made to heat continuously for a predetermined time at a predetermined power P and then the electric heater stops heating, and the predetermined power P is one numerical point, or two or more numerical points.

[0012] Further preferably, after the heating element of the electric heater stops heating, gas continues to be introduced into the flow channel cavity until the temperature of the heating element drops to a predetermined temperature value; or

[0013] After the heating element of the electric heater stops heating, the gas continues to flow into the flow channel cavity within a predetermined time.

[0014] Preferably, the testing method comprises: detecting the temperature value of the heating element at at least one point by a temperature detection device, and / or detecting the temperature value of the outer surface of the electric heater at at least one point.

[0015] Further preferably, the testing method comprises:

[0016] Calculate the heat energy Q generated by the heating element within a predetermined time 电阻 ;

[0017] Calculate the heat Q received by the gas flowing through the flow channel cavity within the predetermined time 气 ;

[0018] Calculate the heat transfer efficiency η of the gas within the predetermined time 气 =Q 气 / Q 电阻 ;

[0019] The heat transfer efficiency of the gas η 气 The theoretical heat transfer efficiency η of the electric heating 理论 By comparison, it is determined whether the electric heater has a qualified heat transfer efficiency.

[0020] Further preferably, the heat transfer efficiency η of the gas is 气 The theoretical heat transfer efficiency η of the electric heater 理论 Comparisons include:

[0021] The heat transfer efficiency of the gas η 气 and the theoretical heat transfer efficiency η of the electric heater 理论 The first ratio is compared with the second ratio of the specific heat capacity of the gas at a predetermined pressure to the specific heat capacity of the theoretical liquid of the electric heater. If the ratio of the first ratio to the second ratio is within a predetermined range, the electric heater has a qualified heat transfer efficiency.

[0022] According to the technical solution of the present application, gas is introduced into the flow channel cavity of the electric heater and the electric heater is started so that the heating element of the electric heater generates heat to heat the gas introduced into the flow channel cavity. The inspection method of water and electricity is changed to the inspection method of air and electricity. There is no need to waste water resources during the product testing process and no water stains will be generated after the inspection. While meeting the purpose of product inspection, the product inspection efficiency is greatly improved, thereby improving the production rhythm.

[0023] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present application, and the schematic implementation modes and descriptions of the present application are used to explain the present application. In the accompanying drawings:

[0025] Figure 1 It is a schematic flow chart of a method for testing an electric heater according to a preferred embodiment of the present application;

[0026] Figure 2 It is a schematic diagram of the electrical control principle of the testing method of the electric heater according to the preferred embodiment of the present application. DETAILED DESCRIPTION

[0027] The technical solution of the present application will be described in detail below with reference to the accompanying drawings and in combination with the implementation modes.

[0028] like Figure 1 As shown, the test method of the electric heater provided in the present application includes steps: 110-120:

[0029] Step 110, introducing gas into the flow channel cavity of the electric heater;

[0030] Specifically, the electric heater of the present application includes at least a heating element, a flow channel cavity and a control circuit. The control circuit controls the start-up of the heating element and can adjust the power of the heating element so that the heating element provides heat energy to the medium in the flow channel cavity, thereby making the electric heater heat up as a whole. Therefore, when testing the electric heater, it is necessary to test the heating effect when there is a medium flowing in the flow channel cavity. In the present application, the medium used for testing is gas, that is, the electric heater is tested by powering on and ventilating.

[0031] In a specific embodiment, the gas used for testing has predetermined parameters to quantify the state of the gas, so as to facilitate the subsequent determination of the performance of the electric heater based on various quantitative parameters. The parameters include at least one of pressure, flow rate, and temperature. The pressure, flow rate, and temperature of the gas at the inlet of the flow channel cavity and the outlet of the flow channel cavity will affect the final detection conclusion of the gas in the electric heater. For example, changes in gas pressure may affect the gas temperature and gas flow rate, and changes in gas flow rate may affect the time the gas is heated, thereby affecting the gas temperature. Changes in gas temperature will directly affect the detection results of the electric heater. Therefore, it is necessary to simultaneously monitor the gas at the inlet of the flow channel cavity and the above parameters at the outlet of the flow channel cavity to control the gas so that the final detection of the electric heater is more accurate.

[0032] In another specific embodiment, gas can be obtained from a compressed air tank, and the pressure and flow rate of the gas flowing into the flow channel cavity of the heater can be controlled by using an air intake solenoid valve and an air pressure control switch.

[0033] Step 120, starting the electric heater to heat the heating element of the electric heater to heat the gas entering the flow channel cavity;

[0034] Specifically, after the gas is introduced into the flow channel cavity, the heating element is started through the control circuit, so that the heating element heats the gas in the flow channel cavity, thereby achieving overall heating of the electric heater, and then realizing the detection of the performance of the electric heater.

[0035] In a specific embodiment, it is necessary to establish a stable airflow in the flow channel cavity before starting the electric heater so that the heating element of the electric heater generates heat to heat the gas that is stably passed into the flow channel cavity. This can reduce the detection error that may be caused by airflow turbulence and make the final detection result more accurate. As for the specific manifestation of the stable airflow, those skilled in the art can refer to the medium flow form setting when the electric heater is in use, or can also customize a specific airflow parameter, which must have a corresponding relationship with the detection standard. How to establish a stable airflow can be specifically described in the embodiment in step 110.

[0036] In another specific embodiment, the heating element can be made to continue to heat for a predetermined time at a predetermined power P, and then the electric heater stops heating. The predetermined power P is a numerical point, or two or more numerical points. If the predetermined power P is a numerical point, it can be understood as keeping the heating element heating at a fixed power for a predetermined time to test the performance of the electric heater under the fixed power state; and if the predetermined power P is two or more numerical points, it can be understood as controlling the heating power of the heating element to change within a predetermined time. This change can be a step-type increase change, or it can be other changes required for testing, so as to test the performance of the electric heater under the condition of adjustable and variable power, thereby realizing multi-angle and multi-form performance measurement of the electric heater.

[0037] In some other embodiments, after the heating element of the electric heater stops heating, it is necessary to continue to pass gas into the flow channel cavity until the temperature of the heating element drops to a predetermined temperature value; or, after the heating element of the electric heater stops heating, it is necessary to continue to pass gas into the flow channel cavity within a predetermined time. It is understandable that after the heating element of the electric heater stops heating, the heating electric heater needs to be cooled down to ensure the safety of the test. Therefore, after the heating element of the electric heater stops heating, the cooling of the electric heater can be completed by continuing to pass gas into the flow channel cavity until the temperature of the heating element drops to a predetermined temperature value; or, after the heating element of the electric heater stops heating, the cooling of the electric heater can also be completed by continuing to pass gas into the flow channel cavity within a predetermined time, and the predetermined time can cool the electric heater.

[0038] Regarding how to test an electric heater that has already heated up, in a specific embodiment, a temperature detection device can be used to detect the temperature value of the heating element at at least one point, and the temperature value of the outer surface of the electric heater at at least one point can be detected to determine whether the current electric heater meets the heating requirements. The above two methods can be used simultaneously or one of them can be used, and this application does not limit this.

[0039] Regarding how to test the heated electric heater, in another specific embodiment, steps 210-240 may also be included:

[0040] Step 210, calculate the heat energy Q generated by the heating element within a predetermined time 电阻 ;

[0041] Specifically, the heating element in this application is heated by a resistance heating method, and Q is calculated. 电阻 The method can be calculated using the resistance parameters of the heating element, and this application does not limit this. It only needs to represent the heat energy generated by the heating element within a predetermined time.

[0042] Step 220, calculate the heat Q received by the gas flowing through the flow channel cavity within a predetermined time 气 ;

[0043] Specifically, calculate Q 气 The method can be calculated based on parameters such as the gas temperature at the inlet and outlet of the flow channel cavity, the temperature of the inside or outer wall of the flow channel cavity, etc. This application is not limited to this, and it only needs to represent the heat received by the gas flowing through the flow channel cavity within a predetermined time.

[0044] Step 230, calculating the heat transfer efficiency η of the gas within a predetermined time 气 =Q 气 / Q 电阻 ;

[0045] Specifically, the heat transfer efficiency can be used to measure the performance of the current electric heater. 气 The larger the value is, the higher the heat transfer efficiency is, the smaller the difference between the heat energy generated by the heating element and the heat energy received by the gas is, and less heat energy is wasted, and vice versa.

[0046] Step 240, the heat transfer efficiency of the gas η 气 Theoretical heat transfer efficiency η of electric heating 理论 By comparison, it is determined whether the electric heater has a qualified heat transfer efficiency.

[0047] Specifically, to detect whether the performance of the electric heater is qualified, a theoretical value η indicating that the performance is qualified can be cited. 理论 , compared with the gas heat transfer efficiency η obtained by current gas testing 气 Theoretical heat transfer efficiency η of electric heating 理论 , judge whether the electric heater has qualified heat transfer efficiency based on the comparison results, rather than based on η alone. 气 The size of η can be used to determine whether the electric heater has a qualified heat transfer efficiency. For example, η 气 With η 理论 If the comparison value between them is within the tolerable range, it is judged that the electric heater has a qualified heat transfer efficiency.

[0048] In a specific embodiment, the heat transfer efficiency of the gas is 气 Theoretical heat transfer efficiency η of electric heater 理论 The comparison includes: the heat transfer efficiency of the gas η 气 and the theoretical heat transfer efficiency η of the electric heater 理论The first ratio of the specific heat capacity of the gas at a predetermined pressure is compared with the second ratio of the specific heat capacity of the theoretical liquid of the electric heater. If the ratio of the first ratio to the second ratio is within a predetermined range, the electric heater is determined to have a qualified heat transfer efficiency. It can be understood that in the normal use state of the electric heater, the medium in the flow channel cavity is liquid. At the same time, when the theoretical heat transfer efficiency η of the electric heater is formulated, 理论 When the medium is liquid, it is also formulated under the execution standard. However, the heat required for liquid and gas to increase the temperature by the same value is different, that is, the "specific heat capacity" of liquid and gas is different. In order to eliminate the possible impact of this difference on the test results, this application also introduces the "specific heat capacity" parameters of the gas and liquid used, and presets a range. If the first ratio of the heat transfer efficiency of the current gas calculated in the test to the theoretical heat transfer efficiency of the electric heater and the second ratio of the current gas's own specific heat capacity to the standard liquid's own specific heat capacity at the same temperature are within the preset range, then although the electric heater is currently tested with gas, it can still be considered that the electric heater still has a qualified heat transfer efficiency.

[0049] Finally, it should be emphasized that the test method in the present application does not introduce any liquid into the flow channel cavity to avoid water stains in the flow channel cavity.

[0050] Next, combine Figure 1 and Figure 2 As shown, Figure 2 The specific implementation shown illustrates the implementation of the present application in a specific circuit control.

[0051] Figure 2 In the figure, S1 to S6 represent switches for various purposes, KM1 and KM2 represent two different contactors and their corresponding feedback control switches, KT1 and KT2 represent two different timers and their corresponding feedback control switches, KA1 represents a relay and its feedback control switch, KQ1 represents an intake solenoid valve, QF1 and QF2 represent AC leakage protection and DC circuit breaker devices respectively, and EL1 represents an indicator light.

[0052] When the test starts, the S1 start switch is first activated, and the circuit self-locking function is realized through the KA1 relay and its corresponding feedback control switch. At the same time, the EL1 working indicator light is on, the KQ1 air intake solenoid valve is powered on, and the compressed air enters the S4 pressure switch.

[0053] When the S4 pressure switch detects that the pressure of the compressed air is greater than the set value, the S4 pressure switch closes, allowing the compressed gas to enter the flow channel cavity of the electric heater. At the same time, the KM1 and KM2 contactors are closed and their corresponding feedback control switches control the KT1 and KT2 timers to start timing, and the electric heater starts testing.

[0054] When the KT1 timing reaches the set value t1, its feedback control switch closes the KM1 and KM2 contactors, and the electric heater is powered off. At this time, KT2 continues to time, and the flow channel cavity of the electric heater continues to be ventilated to cool the electric heater. Until the KT2 timing reaches the set value t2, its feedback control switch disconnects the KA1 relay and the KQ1 intake solenoid valve, and the EL1 light goes out, stopping this round of testing.

[0055] In addition, the high-voltage power supply of the electric heater is controlled by KM1 and KM2 contactors; QF2 DC circuit breaker plays a short-circuit protection role; QF1 is an AC leakage protection switch, which realizes the low-voltage power supply control function through a switching power supply (220VAC to 24VDC); S2 is an emergency stop switch, which is used for emergency shutdown of circuit safety; S3 is a limit switch, which is used to detect whether the electrode connection block of the electric heater is in good contact; S5 and S6 are temperature control switches, which are used to disconnect the circuit after detecting overheating of the electric heater to achieve multi-level redundant protection.

[0056] The testing method provided in the present application, by passing gas into the flow channel cavity of the electric heater, starts the electric heater, and makes the heating element of the electric heater generate heat to heat the gas passed into the flow channel cavity, thereby changing the inspection method of passing water and electricity to the inspection method of passing air and electricity. There is no need to waste water resources during the product testing process, and no water stains will be generated after the test. While meeting the purpose of product inspection, the product inspection efficiency is greatly improved, thereby improving the production cycle.

[0057] The preferred embodiments of the present application are described in detail above; however, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present application.

[0058] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

[0059] In addition, the various implementation modes of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed by the present invention.

Claims

1. Test method for electric heaters, the test method comprising: Gas is introduced into the flow channel cavity of the electric heater, and the electric heater is started to make the heating element of the electric heater generate heat to heat the gas introduced into the flow channel cavity.

2. The method for testing an electric heater according to claim 1, wherein: The test method does not introduce any liquid into the flow channel cavity.

3. The method for testing an electric heater according to claim 1, wherein: The gas introduced into the flow channel cavity has predetermined parameters, which include at least one of pressure, flow rate and temperature.

4. The method for testing an electric heater according to claim 3, wherein: The test method includes: The parameter of the gas flowing into the inlet of the flow channel cavity is monitored, and the parameter of the gas flowing out of the outlet of the flow channel cavity is monitored.

5. The method for testing an electric heater according to claim 1, wherein: After a stable airflow is established in the flow channel cavity, the electric heater is started to make the heating element of the electric heater generate heat to heat the gas passing into the flow channel cavity.

6. The method for testing an electric heater according to claim 5, wherein: The heating element is made to heat continuously for a predetermined time at a predetermined power P, and then the electric heater stops heating. The predetermined power P is one numerical point, or two or more numerical points.

7. The method for testing an electric heater according to claim 6, wherein: After the heating element of the electric heater stops heating, the gas continues to be introduced into the flow channel cavity until the temperature of the heating element drops to a predetermined temperature value; or After the heating element of the electric heater stops heating, the gas continues to flow into the flow channel cavity within a predetermined time.

8. The method for testing an electric heater according to claim 1, wherein: The testing method comprises: detecting the temperature value of the heating element at at least one point by a temperature detection device, and / or detecting the temperature value of the outer surface of the electric heater at at least one point.

9. The method for testing an electric heater according to any one of claims 1 to 7, wherein: The test method includes: Calculate the heat energy Q generated by the heating element within a predetermined time 电阻 ; Calculate the heat Q received by the gas flowing through the flow channel cavity within the predetermined time 气 ; Calculate the heat transfer efficiency η of the gas within the predetermined time 气 =Q 气 / Q 电阻 ; The heat transfer efficiency of the gas η 气 The theoretical heat transfer efficiency η of the electric heating 理论 By comparison, it is determined whether the electric heater has a qualified heat transfer efficiency.

10. The method for testing an electric heater according to claim 9, wherein: The heat transfer efficiency of the gas is 气 The theoretical heat transfer efficiency η of the electric heater 理论 Comparisons include: The heat transfer efficiency of the gas η 气 and the theoretical heat transfer efficiency η of the electric heater 理论 The first ratio is compared with the second ratio of the specific heat capacity of the gas at a predetermined pressure to the specific heat capacity of the theoretical liquid of the electric heater. If the ratio of the first ratio to the second ratio is within a preset range, the electric heater has a qualified heat transfer efficiency.

Images