A laboratory box-type resistance furnace energy efficiency testing device and method

Abstract

The present invention discloses a laboratory box-type resistance furnace energy efficiency test device, including: a box-type resistance furnace temperature test device and an energy consumption test device; wherein the box-type resistance furnace temperature test device includes a box-type resistance furnace temperature test bracket, a temperature test thermocouple anode wire, a temperature test thermocouple cathode wire, a thermocouple protective film, a compensation wire, and a temperature data acquisition and recording device; the energy efficiency test device includes an energy consumption test device, a control module, and a connecting wire. Based on the above device, the present invention also proposes a laboratory box-type resistance furnace energy efficiency test method, including a box-type resistance furnace empty furnace heating energy efficiency test method and a box-type resistance furnace empty furnace constant temperature energy efficiency test method. The present invention indirectly promotes the technical upgrade and energy efficiency control of the equipment by identifying the energy consumption of the equipment, ultimately achieving the purpose of energy saving and consumption reduction, promoting the development and progress of industry technology, and also contributing to the creation of a green laboratory.

Description

Technical Field

[0001] The invention belongs to the technical field of resistance furnaces, and relates to a laboratory box-type resistance furnace energy efficiency testing device and method. Background Art

[0002] Energy is the foundation of human survival and material development, and it occupies a particularly important position in the national economy. Energy efficiency is one of the important indicators for judging the energy-saving degree of products. Energy conservation and emission reduction have become a general consensus of the public in recent years. Box-type resistance furnaces are widely used in production and experiments in the fields of ceramics, metallurgy, electronics, glass, chemicals, machinery, biology, medicine, food, refractory materials, new material development, special materials, building materials, etc. It is widely used in enterprises, institutions, colleges and universities, scientific research institutes and inspection and testing institutions for sintering of metal materials and ceramic materials, heat treatment of single crystals, high-temperature reburning shrinkage of refractory materials, quality inspection and drug inspection ash content detection and aerospace fatigue testing.

[0003] There are testing methods and general consensus on energy efficiency standards for household appliances and automobiles at home and abroad, but there is still a lack of energy efficiency testing and calculation methods for high-energy-consuming equipment in laboratories. The operating temperature of a box-type resistance furnace is usually 500℃ to 1200℃, with resistance wire, silicon carbon rod, and silicon molybdenum rod as heating elements. The power ranges from several kilowatts to tens of kilowatts. It works continuously for several hours each time. It is used frequently and consumes huge energy. It is a major power consumer in the laboratory. Research on energy efficiency test methods for box-type resistance furnaces promotes the development and progress of industry technology and also contributes to building green laboratories.

[0004] The research on energy efficiency test and calculation method of box-type resistance furnace has the following purposes and significance:

[0005] 1. Wide application fields and applicable industries

[0006] Box-type resistance furnaces are widely used in production and experiments in the fields of ceramics, metallurgy, electronics, glass, chemicals, machinery, biology, medicine, food, refractory materials, new material development, special materials, building materials, etc. They are widely used in enterprises, institutions, colleges, scientific research institutes and inspection and testing institutions for sintering of metal materials and ceramic materials, heat treatment of single crystals, high-temperature reburning shrinkage of refractory materials, quality inspection, drug inspection, ash content testing, and aerospace fatigue testing.

[0007] As a commonly used analytical instrument in laboratories, box-type resistance furnaces have achieved leapfrog development in the past decade. After experiencing a low period from 2007 to 2009, they have developed rapidly since 2010. According to relevant data statistics from Wind, the annual output of box-type resistance furnaces exceeded 10,000 units in 2014. In recent years, with the continuous deepening of my country's basic material aerospace research and the continuous increase in investment, the market for box-type resistance furnaces has also been growing year by year. Box-type resistance furnaces are equipment that are routinely configured by testing technology institutions and laboratories. The demand for such equipment in a single professional laboratory ranges from a few to dozens of units. The service life of these equipment is usually about 10 years. With the continuous improvement of the quality control level of raw materials by large-scale production enterprises, the demand for such equipment is growing day by day.

[0008] 2. The demand for energy saving and consumption reduction is becoming increasingly prominent

[0009] The operating temperature of the box-type resistance furnace is usually 500℃ to 1200℃. The resistance wire, silicon carbon rod, and silicon molybdenum rod are used as heating elements. The power ranges from several kilowatts to tens of kilowatts. Each time it works continuously for several hours, it is used frequently and consumes huge energy. It is a large power consumer in the laboratory. Since there is currently no standard method for energy efficiency testing of this type of product, manufacturers and users often only focus on the performance parameters of the product without considering the power consumption, which causes a huge waste of social energy. In order to cut corners and pursue profits, some manufacturers are still producing products with high energy consumption and poor performance. With the continuous improvement of technology, customers' requirements for energy conservation and environmental protection are constantly increasing. Box-type resistance furnace manufacturers also hope to certify the parameters specifically for the instrument, provide strong and authoritative data for the promotion and application of equipment, and gradually eliminate backward products.

[0010] Research the energy efficiency testing methods of box-type resistance furnaces, improve the level of metrology services for national strategies, play a positive role in industrial transformation and upgrading, ecological environment improvement, and people's livelihood security, and effectively support high-quality development.

[0011] In order to establish the energy efficiency test method for high-energy-consuming laboratory equipment as soon as possible, the National Technical Committee for Standardization of Laboratory Instruments and Equipment (SAC / TC526) is responsible for leading the formulation of this series of standards. Among them, the "Energy Efficiency Test Method for High-Energy-Consuming Laboratory Equipment Box-Type Resistance Furnace" was drafted by the Shanghai Institute of Metrology and Testing Technology, and has been approved as the third batch of industry standards of the Ministry of Industry and Information Technology in 2020 (plan number 2020-1708T-JB). The person in charge of the present invention and the main members are the first and second drafters of the standard and are responsible for drafting the standard.

[0012] my country is a country with large energy consumption. Energy conservation and emission reduction have become the goal pursued by all walks of life in recent years. In 2012, the National Development and Reform Commission and the National Standardization Administration decided to launch the "100 Energy Efficiency Standards Promotion Project", and planned to release 100 important energy-saving standards. Industrial electric heating devices are listed among them as typical energy-consuming terminal equipment. Industrial resistance furnaces, as typical industrial electric heating devices, formulated and implemented GB / T30839.4-2015 "Energy Consumption of Industrial Electric Heating Devices Part 4: Resistance Furnaces" in 2015. This standard is aimed at large industrial resistance furnaces. This type of equipment has high power (usually more than 50kW) and maintains a constant temperature for a long time during the production process. Therefore, this standard assesses three indicators of resistance furnace empty furnace loss ratio, surface temperature rise, and unit power consumption. Empty furnace loss ratio refers to the ratio of the power lost by the furnace body of a resistance furnace without charge at a thermally stable state at the rated working temperature to the rated power; surface temperature rise refers to the difference between the temperature of any point within a specified range on the outer surface of the furnace body and the ambient temperature when the resistance furnace is in a thermally stable state at the rated working temperature; unit power consumption refers to the power consumed by the resistance furnace to process a unit charge or workpiece under the conditions specified in the test method. Internationally, the US military technical specification MIL-F-80258 and other standards have standardized the test methods and calculation formulas for indicators such as the surface temperature rise of box-type resistance furnaces, but research on variable temperature energy efficiency is still blank.

[0013] The purpose of using a box-type resistance furnace for laboratory use is different from that of an industrial resistance furnace. The box-type resistance furnace for laboratory use focuses on experimental analysis, sample testing, product trials, etc. Its power is usually around 10kW to 50kW, and the operating temperature needs to be adjusted according to the experimental requirements. The box body is usually small and is not used for producing or processing large amounts of furnace materials. The energy consumption of a box-type resistance furnace is the largest during the heating stage. Therefore, the present invention focuses on studying the test method and calculation formula for the energy efficiency of a box-type resistance furnace for laboratory use, and studies and derives the test method and calculation formula for its variable temperature energy efficiency and constant temperature energy efficiency. Summary of the invention

[0014] The present invention focuses on the box-type resistance furnace with high energy consumption and long use time in the laboratory, and studies the energy efficiency test and calculation method of the box-type resistance furnace. Standardize the method and evaluation basis of the energy efficiency test of the box-type resistance furnace, in line with the principles of science, openness, applicability and promotion of energy efficiency, energy conservation and emission reduction in my country's laboratories, conduct in-depth research on the energy-saving requirements of my country's box-type resistance furnaces, actively promote energy efficiency improvement, and formulate the "High Energy Consumption Laboratory Equipment Energy Efficiency Test Method Box-type Resistance Furnace" industry and group standards suitable for my country's current application, gradually eliminate high-energy consumption and low-efficiency products, promote the product progress and development of related enterprises, promote industrial upgrading and transformation, promote green and efficient development strategies, and provide technical basis for the national energy conservation and emission reduction strategy.

[0015] The main technical contents of the present invention are as follows:

[0016] 1) Aiming at the problem of lack of energy efficiency test method for box-type resistance furnace, the energy efficiency test method for box-type resistance furnace (empty furnace heating test and constant temperature test) was studied;

[0017] The energy efficiency test method of the box-type resistance furnace fully considers the two main states of daily use and large energy consumption of the laboratory box-type resistance furnace, namely the heating state and the constant temperature state. The energy efficiency test methods of the empty furnace heating test and the constant temperature test of the box-type resistance furnace are studied respectively. The energy efficiency test conditions and influencing factors of the box-type resistance furnace required for the test are studied and determined, the temperature test method of the heating process, the measurement range and technical requirements of the temperature measuring instrument, and the measurement range and technical requirements of the electric energy measuring instrument. Determine the empty furnace heating energy efficiency test method and the constant temperature energy efficiency test method of the box-type resistance furnace.

[0018] 2) Aiming at the problem of lack of energy efficiency calculation method for box-type resistance furnace, the energy efficiency calculation method for box-type resistance furnace (empty furnace heating energy efficiency, constant temperature energy efficiency) is studied;

[0019] The energy efficiency calculation of box-type resistance furnace is divided into two parts: empty furnace heating energy efficiency calculation and constant temperature energy efficiency calculation. The influencing factors under the empty furnace heating state are studied and determined, and the influence of furnace size, air specific heat capacity and density at the beginning of heating, furnace heating rate, and heating start and end temperatures on heating energy efficiency are considered. The influencing factors of the energy efficiency of the box-type resistance furnace under the constant temperature state are studied and determined, and the influence of furnace size on constant temperature energy efficiency is considered. The calculation formulas for the empty furnace heating energy efficiency and constant temperature energy efficiency of the box-type resistance furnace are obtained, and their rationality is studied.

[0020] 3) Trial production of box-type resistance furnace energy efficiency test device

[0021] During the empty furnace heating test of a box-type resistance furnace, it is necessary to measure the temperature at the geometric center of the box-type resistance furnace. Since the maximum working temperature of a box-type resistance furnace is generally higher than 1000°C, the production of the test bracket is particularly important. It is necessary to ensure accurate measurements and ensure that the test device does not deform or damage within the maximum operating temperature range of 1600°C of the box-type resistance furnace.

[0022] Technical ideas adopted by the invention:

[0023] 1) Research on the energy efficiency test method of box-type resistance furnace (empty furnace heating test and constant temperature test)

[0024] Research and determine the environmental conditions, power supply conditions, test instruments used and their technical requirements required for the energy efficiency test of box-type resistance furnaces.

[0025] Study the test method of the energy efficiency of the box-type resistance furnace during the empty furnace heating process and the constant temperature process, analyze the influencing factors in the test process, determine the research parameters, study the relationship between the temperature in the heating and constant temperature processes and the energy efficiency of the box-type resistance furnace, study the temperature test method of the box-type resistance furnace during the heating and constant temperature processes, and analyze the sources of errors in the test process.

[0026] 2) Study the energy efficiency calculation method of box-type resistance furnace (empty furnace heating energy efficiency, constant temperature energy efficiency)

[0027] Use a power analyzer to test the power consumption of a box-type resistance furnace during the empty furnace heating process. Study the effects of the empty furnace heating start temperature, empty furnace heating end temperature, air specific heat capacity, air density, and the volume of the working area of ​​the box-type resistance furnace on the energy efficiency under the empty furnace heating test. Derived and determined the empty furnace heating energy efficiency calculation formula of the box-type resistance furnace. At the same time, the empty furnace heating rate was obtained, and the relationship between it and the empty furnace heating energy efficiency was studied. Evaluate the uncertainty of the test process.

[0028] Test the power consumption per hour of the box-type resistance furnace under constant temperature. Study the influence of the working area volume of the box-type resistance furnace on the energy efficiency under constant temperature test. Derive and determine the calculation formula of the constant temperature energy efficiency of the box-type resistance furnace, and evaluate the uncertainty of the test process.

[0029] 3) Trial production of box-type resistance furnace energy efficiency test device

[0030] Trial-produce a box-type resistance furnace energy efficiency test device, and study and prepare the high-temperature resistant fixture required for the temperature test of the geometric center point of the box-type resistance furnace. The fixture is used to place the temperature measurement equipment to ensure the accuracy of the test position and the reliability of the temperature test data. Temperature testing is the key to the energy efficiency of the empty furnace heating of the box-type resistance furnace, and the accuracy of the test is related to the results of the energy efficiency test. Therefore, the box-type resistance furnace energy efficiency test device plays an important role in the accuracy of its energy efficiency test.

[0031] Specific technical roadmaps include Figure 5 shown.

[0032] In order to solve the deficiencies of the prior art, the present invention provides a box-type resistance furnace energy efficiency testing device and method for laboratory use, so as to achieve the purpose of energy saving and consumption reduction and promote the development and progress of industry technology.

[0033] The present invention provides a box-type resistance furnace energy efficiency testing device for laboratory use, comprising: a box-type resistance furnace temperature testing device 1 and an energy consumption testing device 2.

[0034] The box-type resistance furnace temperature testing device 1 includes a box-type resistance furnace temperature testing bracket 3, a temperature testing thermocouple anode wire 4, a temperature testing thermocouple cathode wire 5, a thermocouple protective film 6, a compensation wire 7, a temperature data acquisition and recording device 8, a standard temperature measuring material 15, and a connecting wire 16.

[0035] The energy consumption test device 2 includes an energy consumption test device 9 , a control module 10 and a connecting wire 11 .

[0036] The box-type resistance furnace temperature testing device 1 is electrically connected to the energy consumption testing device 2 .

[0037] The box-type resistance furnace temperature test bracket 3 is made of high temperature resistant insulating material (such as ceramics) to ensure that it does not deform under the extremely high temperature conditions of the box-type resistance furnace test, and at the same time ensure that other metal materials are not introduced during the temperature test to affect the temperature test results. It is composed of a base 12 and at least two support rods 13. Support rods 13 of different sizes can be selected according to the size of the box-type resistance furnace box to ensure that the temperature test point is at the geometric center of the box-type resistance furnace during the box-type resistance furnace energy efficiency test. After selecting a suitable support rod 13 according to the size of the box-type resistance furnace box, the support rod 13 is inserted into the base 12 and fixed.

[0038] The temperature test thermocouple anode wire 4 is physically connected to the box-type resistance furnace temperature test bracket 3. One end of the temperature test thermocouple anode wire 4 is connected to the base 12 of the box-type resistance furnace temperature test bracket 3, and the other end is led out of the furnace body through the fixing hole of the support rod 13 and then through the furnace door of the box-type resistance furnace. The temperature test thermocouple anode wire 4 uses common thermocouple anode materials (such as nickel-chromium), and there are cathode fixed connection holes 14 every 1 cm to facilitate the connection of the temperature test thermocouple cathode wire 5. The purpose of this setting is to ensure that the temperature measurement point of the box-type resistance furnace is at the center of the box-type resistance furnace body, and a temperature measurement point is formed at this point. The cathode fixed connection hole 14 is formed by winding the temperature test thermocouple anode wire 4.

[0039] The temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 are interchangeable.

[0040] The temperature test thermocouple cathode wire 5 is made of common thermocouple cathode material. One end is connected to the temperature test thermocouple anode wire 4 cathode fixed connection hole 14, and the other end is led out of the furnace body through the furnace door of the box-type resistance furnace. The connection point between the cathode wire 5 and the anode wire 4 is the temperature test point. Common materials for anode wires are nickel-chromium, platinum-rhodium 10, etc., and common materials for corresponding cathode wires are nickel-silicon, pure platinum, etc.

[0041] The thermocouple protection film 6 is made of high temperature resistant insulating materials such as asbestos, and is used to protect the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 from passing through the box-type resistance furnace door, and at the same time, it plays the role of insulating the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 from the box-type resistance furnace door. The thermocouple protection film 6 is only set at the contact between the tested box-type resistance furnace door and the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5.

[0042] The compensation wire 7 is used to connect the temperature data acquisition and recording device 8 with the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5. The anode of the compensation wire 7 and the temperature test thermocouple anode wire 4 are made of the same material, and the cathode of the compensation wire 7 and the temperature test thermocouple cathode wire 5 are made of the same material. The compensation wire 7 and the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 are connected by a socket, and the compensation wire 7 and the temperature data acquisition and recording device 8 are connected by a socket. Both ends of the standard temperature measuring material 15 are connected to the connecting wire 16; the connecting wire 16 and the control module 10 are electrically connected; the standard temperature measuring material 15, the connecting wire 16 and the control module 10 form a current loop;

[0043] The temperature data acquisition and recording device 8 collects temperature data and performs calculations; during the box-type resistance furnace heating energy efficiency test, the corresponding standard temperature measuring material 15 is selected according to the maximum working temperature of the box-type resistance furnace. When the standard temperature measuring material 15 melts and breaks, the current loop formed by the standard temperature measuring material 15, the connecting wire 16 and the control module 10 is broken; during the box-type resistance furnace constant temperature energy efficiency test, after the maximum working temperature of the box-type resistance furnace is input, the temperature data acquisition and recording device 8 determines whether the collected temperature of the geometric center point of the box-type resistance furnace body reaches the maximum working temperature of the box-type resistance furnace within ±5°C. If so, the temperature is reached. The signal is output, and then it is continuously determined whether the temperature inside the box-type resistance furnace is within the corresponding working temperature range, that is, ±5°C of the maximum working temperature. If it exceeds the range, the temperature exceeds the range signal is output.

[0044] The standard temperature measuring substance 15 is made of metal or alloy material with high melting point and stability, such as pure gold, pure copper, brass H62, etc. The connecting wire 16 is connected to the standard temperature measuring substance 15, and is physically connected to the box-type resistance furnace temperature support 3 through the fixing hole of the support rod 13, and is led out of the furnace body through the box-type resistance furnace door. The compensation wire 16 is made of high-temperature resistant metal or alloy material, such as pure platinum, nickel silicon, etc., and the melting point of the material must be higher than the melting point of the standard temperature measuring substance 15; during the test, the standard temperature measuring substance 15 is ensured to be in the geometric center of the box-type resistance furnace body by adjusting the size of the support rod 13, the position of the box-type resistance furnace temperature support 3, and the length and position of the compensation wire 7.

[0045] The energy consumption test device 2 includes an energy consumption test device 9 , a control module 10 and a connecting wire 11 .

[0046] The control module 10 communicates with the temperature data acquisition and recording device 8 and the energy consumption test equipment 9 by software connection, and the energy consumption test equipment 9 is connected to the tested box-type resistance furnace by a connecting wire 11 .

[0047] Based on the above device, the present invention also proposes a laboratory box-type resistance furnace energy efficiency test method.

[0048] Box furnace working status: based on the following test conditions:

[0049] During the energy efficiency test, the box furnace should remain unloaded and meet the following requirements:

[0050] 1. The accessories that are intended to be connected to the box-type furnace to ensure the normal operation of the box-type furnace should be installed and connected according to the installation requirements of the instruction manual;

[0051] 2. For box-type furnaces that are used for the first time or have not been used for a long time, the furnace needs to be dried according to the requirements of the manufacturer's product manual;

[0052] 3. The door of the box furnace should be kept completely closed;

[0053] 4. Open the door of the box-type furnace and leave it vacant for at least 2 hours to make the temperature inside the box-type resistance furnace consistent with the ambient temperature;

[0054] 5. For box-type resistance furnaces equipped with fans, the fans should operate normally during the test.

[0055] 6. This method is applicable to the energy efficiency test of box-type resistance furnaces for natural atmosphere and protective atmosphere experiments with working temperatures between 100°C and 1600°C. During the energy efficiency test of box-type resistance furnaces for protective atmosphere experiments, the corresponding protective gas needs to be introduced.

[0056] Measurement of working area: Use a steel tape measure to measure the geometric shape of the working area of ​​the box-type furnace according to 7.3.2 of JJF 1376-2012. The result is the working area of ​​the box-type furnace, which is represented by V.

[0057] Measurement of geometric center temperature: Place the temperature measuring probe of the temperature measuring device at the geometric center of the box furnace and test the temperature every 3 minutes. For the geometric center, see 6.3.1.3 of GB / T28849-2012.

[0058] Box furnace test temperature: Set the box furnace test temperature to the highest operating temperature.

[0059] Empty furnace heating test: The box furnace should be fully dried before the test. Connect the power supply when the furnace is cold and empty, and heat it to the highest working temperature at the maximum temperature change rate. Record the starting and ending temperatures of the geometric center point, the power consumption E1 in the temperature rise range, and the heating time T.

[0060] Constant temperature test: After setting the temperature of the geometric center point of the box-type furnace to the maximum operating temperature within ±5℃, maintain the thermal stability for 2h and record the power consumption in the next 1h, which is represented by E2.

[0061] The energy efficiency test method of the box-type resistance furnace for laboratory use specifically includes the following steps:

[0062] 1. Box-type resistance furnace empty furnace heating energy efficiency test method:

[0063] 1. Measure the volume of the working area of ​​the box-type resistance furnace, represented by V; select a suitable support rod 13 according to the size of the resistance furnace box, and then build a temperature test bracket 3 to determine the geometric center position of the box-type resistance furnace: select a temperature test thermocouple cathode wire 5 to connect to the cathode fixed connection hole 14 of the temperature test thermocouple anode wire 4, and the cathode fixed connection hole 14 is located at the geometric center position of the box-type resistance furnace box. The connection point between the temperature test thermocouple cathode wire 5 and the temperature test thermocouple anode wire 4 is the temperature test point; connect the connecting wire 16 to the control module 10;

[0064] 2. Place the temperature probe of the box-type resistance furnace temperature test device 1 at the geometric center of the box-type resistance furnace through the box-type resistance furnace temperature test bracket 3; connect the standard temperature measuring material 15 to the connecting wire 16, and the standard temperature measuring material 15 is located at the geometric center of the box-type resistance furnace;

[0065] 3: Test the temperature every 3 minutes; specifically, select a suitable support rod 13 according to the size of the resistance furnace box, and then build a temperature test bracket 3. Select one of the cathode thermocouple wires to connect through the anode thermocouple wire fixing hole, and the fixing hole is located at the geometric center of the box-type resistance furnace box. The connection point is the temperature test point. Introduce protective gas at the rated flow rate, stabilize for 30 minutes, and continue to introduce it during the subsequent test process;

[0066] 4. Set the test temperature of the box-type resistance furnace to the highest operating temperature;

[0067] 5. The box-type resistance furnace should be fully dried before the test. When the furnace is cold and empty, connect the power supply and heat it to the maximum operating temperature at the maximum temperature change rate. When the temperature measured by the box-type resistance furnace temperature test device 1 reaches the set maximum operating temperature within ±5°C.

[0068] After the test starts, the energy consumption test device 2 starts working. Record the starting and ending temperatures of the geometric center point, and the power consumption E in the temperature rise range. 1 , heating time T.

[0069] 6. As the temperature rises, when the standard temperature measuring material 15 melts and breaks, the current loop formed by the standard temperature measuring material 15, the connecting wire 16 and the control module 10 is disconnected, and the energy consumption test device 9 stops recording the power consumption, and the starting temperature and ending temperature of the geometric center point and the power consumption E in the temperature rise range are obtained. 1 At the same time, the actual temperature t at the geometric center of the box-type resistance furnace is measured by the thermocouple. 3 ; According to the standard temperature measurement material 15 inherent melting point temperature t 2 The calculations are shown in formula (1) and formula (2) respectively, and the empty furnace heating efficiency is further calculated.

[0070] C 1 =E 1 / [(t 2 -t 1 )·c·V·ρ] (1)

[0071] v=(t 2 -t 1 ) / T (2)

[0072] Where:

[0073] C 1 ——Energy efficiency under empty furnace heating test, unit is 1;

[0074] E 1 ——Power consumption in empty furnace heating test, in joule (J); measured by direct reading;

[0075] t 1 ——The starting temperature of the empty furnace heating test, in degrees Celsius (℃); measured by direct reading;

[0076] t 2 ——t 2 It is the inherent melting point temperature of the standard temperature measuring material, in degrees Celsius; it is measured by direct reading;

[0077] c——Specific heat capacity of the protective gas introduced at the initial temperature under standard atmospheric pressure, in joules per kilogram Celsius (J / (kg·℃));

[0078] V——Box furnace working area, in cubic meters (m 3 );

[0079] r——The density of the protective gas at the starting temperature under standard atmospheric pressure, in kilograms per cubic meter (kg / m 3 );

[0080] v——Temperature change rate during the empty furnace heating process, in degrees Celsius per minute (℃ / min);

[0081] T——empty furnace heating test time, in minutes (min).

[0082] V = V1-V2, V1 is the volume of the box-type furnace body, V2 is the volume of the insulation layer of the box-type furnace door;

[0083] The reliability of the test process is determined by the formula (3) and compared with the actual measured temperature t 3 and the inherent melting point temperature t of the standard temperature measuring material 2 , determine the reliability of the temperature rise test. When formula (3) holds true, the test is reliable and the data is available;

[0084] Formula (3)(t 3 -10)≤t 2 ≤(t 3 +10).

[0085] The specific heat capacity of air at 23°C under standard atmospheric pressure is 1.004 kJ / (kg·°C), and the air density is 1.193 kg / m 3 .

[0086] 2. Box-type resistance furnace empty furnace constant temperature energy efficiency test method:

[0087] 1. Measure the volume of the working area of ​​the box-type resistance furnace, represented by V; select a suitable support rod 13 according to the size of the resistance furnace box, and then build a temperature test bracket 3 to determine the geometric center position of the box-type resistance furnace: select a temperature test thermocouple cathode wire (5) to connect to the cathode fixed connection hole (14) of the temperature test thermocouple anode wire (4), and the cathode fixed connection hole (14) is located at the geometric center position of the box-type resistance furnace box. The connection point between the temperature test thermocouple cathode wire (5) and the temperature test thermocouple anode wire (4) is the temperature test point;

[0088] 2. Place the temperature probe of the box-type resistance furnace temperature test device 1 at the geometric center of the box-type resistance furnace through the box-type resistance furnace temperature test bracket (3), and test the temperature every 3 minutes;

[0089] 3. Introduce protective gas at rated flow rate, stabilize for 30 minutes, and continue to introduce it during the subsequent test;

[0090] 4. After the test starts, the temperature measured by the temperature measuring device reaches the set maximum operating temperature within ±5°C, and the thermal stability is maintained for 2 hours. When the temperature data acquisition and recording device 8 outputs the temperature reaching signal, the energy consumption test device 2 starts working and records the power consumption for the next 1 hour. 2 express.

[0091] 5. After 1 hour, the energy consumption test device 2 stops recording and further calculates the energy efficiency of the empty furnace at constant temperature. In this process, if the temperature data acquisition and recording device 8 outputs a signal indicating that the temperature is out of range, the energy consumption recording is stopped and an abnormal alarm is issued.

[0092] Calculate the constant temperature energy efficiency. See formula (4) for the constant temperature energy efficiency calculation.

[0093] C 2 =E 2 / V (4)

[0094] Where:

[0095] C 2——Energy efficiency of constant temperature test, in joules per cubic meter (J / m 3 );

[0096] E 2 ——power consumption of constant temperature test, in joule (J);

[0097] V——Box furnace working area, in cubic meters (m 3 ); V = V1-V2, V1 is the volume of the box-type furnace body, and V2 is the volume of the insulation layer of the box-type furnace door.

[0098] The beneficial effects of the present invention are:

[0099] Aiming at the problem of lack of energy efficiency testing method and calculation formula for box-type resistance furnace, a high energy-consuming equipment in laboratory, the present invention starts with the energy efficiency test of the box-type resistance furnace in the empty furnace heating state (variable temperature energy efficiency) and the energy efficiency test in the constant temperature state (constant temperature energy efficiency), studies the energy efficiency testing method of the box-type resistance furnace with a maximum temperature below 1600°C, and derives and summarizes the energy efficiency testing calculation method of the box-type resistance furnace.

[0100] The present invention provides a basis and reference for the energy efficiency testing method of a box-type resistance furnace. By identifying the energy consumption of the equipment, it indirectly promotes the technical upgrading and energy efficiency control of the equipment, ultimately achieving the purpose of energy saving and consumption reduction, promoting the development and progress of industry technology, and also contributing to building a green laboratory.

[0101] The main purpose of the present invention to abandon the traditional thermocouple and adopt the special thermocouple form in the present invention is that the traditional thermocouple processes the thermocouple anode wire and the thermocouple cathode wire in the thermocouple protective sleeve at the same time, which is relatively thick (about 3mm). When passing through the door of the box-type resistance furnace, it will cause a large gap in the door of the box-type resistance furnace, affecting the heating and insulation of the box-type resistance furnace, further affecting the temperature test of the box-type resistance furnace, increasing the energy consumption of the box-type resistance furnace, and causing errors in the energy efficiency test of the box-type resistance furnace. In addition, the traditional thermocouple is also difficult to fix at the geometric center position of the box-type resistance furnace, and the position of the thermocouple will be affected and offset when the door of the box-type resistance furnace is opened and closed. The thermocouple anode wire and the thermocouple cathode wire are adopted, and the thermocouple protective film is formed on the part of the area where the thermocouple passes through the door of the box-type resistance furnace, and the thickness of the thermocouple passing through the door is reduced to (<0.5mm), which greatly reduces the errors in the temperature measurement and energy efficiency of the box-type resistance furnace.

[0102] This invention is aimed at the fields of Beautiful China and energy, environmental monitoring, evaluation and governance, as well as the urgent needs for measurement technology in energy production, use and trade. It targets large energy consumers in laboratories: box-type resistance furnaces. It conducts energy efficiency testing and analysis in combination with my country's specific conditions, promotes the improvement of the energy efficiency of box-type resistance furnaces, and strongly supports my country's green, sustainable and high-quality development.

[0103] The invention meets the requirements of serving the construction of ecological civilization. Carry out research and application of key measurement and testing technologies in key areas such as industrial energy conservation and building energy conservation. Research on energy efficiency testing methods for high-energy-consuming experimental equipment box-type resistance furnaces will enhance the product progress and development of related companies, promote industrial upgrading and transformation, and promote green, efficient and sustainable development strategies.

[0104] This invention draws on existing standards in the field of energy efficiency at home and abroad, and combines my country's specific conditions. Based on the principles of science, openness, applicability and promotion of energy efficiency, energy conservation and emission reduction in my country's laboratories, it conducts in-depth research on the energy-saving requirements of my country's box-type resistance furnaces, actively promotes energy efficiency improvement, and develops an energy efficiency test method for box-type resistance furnaces currently used in my country.

[0105] The main innovations of the device of the present invention are: temperature measuring bracket, temperature measuring thermocouple anode wire, cathode wire and thermocouple protective film

[0106] The main innovative points of the present invention are:

[0107] 1) Research on energy efficiency test method of box-type resistance furnace.

[0108] The research determines the test methods of empty furnace heating energy efficiency and constant temperature energy efficiency of box-type resistance furnace. The influencing factors of empty furnace heating energy efficiency and constant temperature energy efficiency of box-type resistance furnace are analyzed.

[0109] 2) Derivation of energy efficiency calculation method for box-type resistance furnace.

[0110] The research deduces the calculation formula for the empty furnace heating energy efficiency and constant temperature energy efficiency test of the box-type resistance furnace. The relationship between the various influencing factors of the empty furnace heating energy efficiency and constant temperature energy efficiency of the box-type resistance furnace is determined.

[0111] 3) Design and preparation of box-type resistance furnace energy efficiency test device

[0112] The key to the box-type resistance furnace energy efficiency test device is the temperature measurement fixture at the geometric center of the box-type resistance furnace. This fixture is used to test the temperature at the geometric center of the box-type resistance furnace in the empty furnace heating state. Since the temperature changes rapidly and the temperature change amplitude is large during the heating process, it is particularly important that the fixture does not deform and does not affect the temperature measurement during this process. It meets the testing needs of box-type resistance furnaces of different sizes.

[0113] The expected economic and social benefits and promotion and application of this invention:

[0114] Box-type resistance furnaces are mainly used for analysis and research and development in universities, research institutes, industrial and mining enterprise laboratories, etc. The main markets and manufacturers of box-type resistance furnaces are distributed in the eastern coastal areas. Therefore, Shanghai, as an important market for box-type resistance furnaces, has dozens of box-type resistance furnace manufacturers and import agents, and has a large demand for energy efficiency testing. As users continue to pay attention to energy conservation and emission reduction, manufacturers' demand for energy efficiency testing of products is also increasing. It is estimated that the testing business income generated by the initial invention will be about 50,000 yuan / year. As customers, manufacturers, and the country pay more attention to the energy efficiency of high-energy-consuming products in laboratories, the mid- and late-stage testing business income is expected to exceed 500,000 yuan / year.

[0115] The present invention is aimed at the research on energy efficiency testing and calculation methods of box-type resistance furnace, a high-energy-consuming experimental equipment, to promote product progress and development of related enterprises, boost industrial upgrading and transformation, and promote green and efficient development strategies.

[0116] The box-type resistance furnace of the present invention has the function of introducing protective gas, which can protect samples and prevent oxidation during experiments.

[0117] The present invention obtains t by fusing the standard temperature measuring material to short-circuit the electric circuit and immediately stopping the energy consumption test equipment from working. 2 The benefits of doing this are:

[0118] a. Reduce temperature measurement errors. The temperature measurement process is prone to fluctuations and other errors. The response speed of thermocouples is generally around 5s, and the temperature is lower than the measured temperature during the heating process;

[0119] b. Setting and selecting standard temperature measuring materials at specific temperature points, such as 1100℃ and 1200℃, can better compare the energy efficiency tests of similar equipment (for example, the highest temperature calibrated for a box-type resistance furnace is 1200℃. Due to different algorithms, some box-type resistance furnaces directly heat up to 1200℃ at the maximum power, while others heat up to 1100℃ and then reduce the power to heat up slowly). If standard temperature measuring materials of 1100℃ are used for both, the heating energy efficiency can be judged more accurately;

[0120] c. Using standard materials for temperature measurement is relatively rare in the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0121] Figure 1 It is a schematic diagram of the energy efficiency testing device of a box-type resistance furnace for laboratory use of the present invention.

[0122] Figure 2 It is a schematic diagram of the temperature testing bracket of the box-type resistance furnace of the present invention.

[0123] Figure 3 This is an assembly diagram of the temperature testing bracket of the box-type resistance furnace of the present invention.

[0124] Figure 4 It is a schematic diagram of the energy efficiency testing device of a box-type resistance furnace for laboratory use of the present invention.

[0125] Figure 5 This is a specific research roadmap for the present invention.

[0126] Among them: box-type resistance furnace temperature test device 1; energy consumption test device 2; box-type resistance furnace temperature test bracket 3; temperature test thermocouple anode wire 4; temperature test thermocouple cathode wire 5; cathode fixed connection hole 14; thermocouple protective film 6; compensation wire 7; temperature data acquisition and recording device 8; energy consumption test equipment 9; control module 10; second connecting wire 11; base 12; support rod 13; cathode fixed connection hole 14; standard temperature measuring material 15; first connecting wire 16. DETAILED DESCRIPTION

[0127] The invention is further described in detail with reference to the following specific embodiments and drawings. The process, conditions, experimental methods, etc. for implementing the present invention, except for the contents specifically mentioned below, are all common knowledge and common common sense in the art and are not particularly limited by the present invention.

[0128] Energy efficiency test method for high energy consumption laboratory equipment Box type resistance furnace

[0129] The following defines the terms and definitions of the energy efficiency test of box-type resistance furnace (referred to as box-type furnace), and stipulates the technical requirements, test conditions, test methods, etc. of box-type furnace products.

[0130] The invention is suitable for energy efficiency testing of box-type furnaces for natural atmosphere and protective atmosphere experiments with working temperatures ranging from 100°C to 1600°C.

[0131] The contents of the following documents constitute essential clauses of the present invention through normative references in the text. Among them, for referenced documents with dates, only the versions corresponding to the dates are applicable to the present invention; for referenced documents without dates, the latest versions (including all amendments) are applicable to the present invention.

[0132] GB / T 28849-2012SX series experimental box-type resistance furnace

[0133] GB / T 30839.43-2015 Classification of energy consumption of industrial electric heating devices Part 43: Box-type resistance furnace

[0134] JJF 1376-2012 Calibration Specification for Box-type Resistance Furnace

[0135] Box-type resistance furnace: An intermittent resistance furnace with a box-type, horizontal heating chamber and inlet and outlet doors. [GB / T30839.43-2015, 3.1]

[0136] Constant temperature energy efficiency parameter constanttemperatureenergyefficiency: The energy consumed to maintain a constant temperature in the unit working area for 1 hour during the constant temperature process of the box-type furnace. The unit is J / m3.

[0137] Temperature ramping energy efficiency parameter: the ratio of power consumption to the energy required for the conversion temperature change during the heating process of the box furnace. The unit is 1.

[0138] Thermal steady state: A thermodynamic state in which a box-type furnace reaches a balance between heat absorption and heat release. In the thermal steady state, the temperature in the furnace fluctuates within a certain range. [GB / T28849-2012, 3.11]

[0139] Working area: The part of the box furnace where the specified conditions can be maintained within the specified tolerance range.

[0140] Product technical requirements: The performance requirements of box-type furnaces shall comply with the relevant provisions of GB / T28849-2012.

[0141] Environmental conditions

[0142] The environmental test conditions of the box furnace should meet the following requirements:

[0143] Ambient temperature: 23℃±2℃;

[0144] Relative humidity: ≤85%;

[0145] Air pressure: 80kPa~106kPa;

[0146] The ambient air velocity should not be greater than 0.25m / s.

[0147] The ambient temperature (the space temperature around the box furnace) is the temperature measured at the test point 1m away from the vertical center line of the box furnace wall and 1m above the ground (the ambient temperature should not be affected by the outlet temperature of the box furnace).

[0148] Power supply conditions

[0149] The box furnace power supply test conditions should meet the following requirements:

[0150] AC voltage: 220V±6.6V or 380V±11.4V;

[0151] Frequency: 50Hz±0.5Hz.

[0152] Test Equipment

[0153] Electric energy measuring instruments

[0154] Measuring range: The rated voltage and rated current measuring range meet the test requirements;

[0155] Maximum allowable error: no more than ±0.5%;

[0156] Application: Measurement of active power consumption of box-type furnace.

[0157] Temperature measuring instruments

[0158] Measuring range: The temperature measurement range meets the test requirements;

[0159] Technical requirements for temperature measurement equipment: should meet the requirements of JJF 1376-2012, 6.2;

[0160] Application: To measure the geometric center temperature of box furnace.

[0161] Stopwatch

[0162] Daily difference: ±1s.

[0163] Steel measuring tape

[0164] Accuracy level: Level II and above;

[0165] Application: To measure the geometric dimensions of the working area of ​​a box furnace.

[0166] The present invention provides a box-type resistance furnace energy efficiency testing device for laboratory use, comprising: a box-type resistance furnace temperature testing device 1 and an energy consumption testing device 2.

[0167] The box-type resistance furnace temperature testing device 1 comprises a box-type resistance furnace temperature testing bracket 3, a temperature testing thermocouple anode wire 4, a temperature testing thermocouple cathode wire 5, a thermocouple protective film 6, a compensation wire 7, and a temperature data acquisition and recording device 8.

[0168] The energy consumption test device 2 includes an energy consumption test device 9 , a control module 10 and a connecting wire 11 .

[0169] The box-type resistance furnace temperature testing device 1 is electrically connected to the energy consumption testing device 2 .

[0170] The box-type resistance furnace temperature test bracket 3 is made of high temperature resistant insulating material (such as ceramics) to ensure that it does not deform under the extremely high temperature conditions of the box-type resistance furnace test, and at the same time ensure that other metal materials are not introduced during the temperature test to affect the temperature test results. It is composed of a base 12 and at least two support rods 13. Support rods 13 of different sizes can be selected according to the size of the box-type resistance furnace box to ensure that the temperature test point is at the geometric center of the box-type resistance furnace during the box-type resistance furnace energy efficiency test. After selecting a suitable support rod 13 according to the size of the box-type resistance furnace box, the support rod 13 is inserted into the base 12 and fixed.

[0171] The temperature test thermocouple anode wire 4 is physically connected to the box-type resistance furnace temperature test bracket 3. One end of the temperature test thermocouple anode wire 4 is connected to the base 12 of the box-type resistance furnace temperature test bracket 3, and the other end is led out of the furnace body through the fixing hole of the support rod 13 and then through the furnace door of the box-type resistance furnace. The temperature test thermocouple anode wire 4 uses common thermocouple anode materials (such as nickel-chromium), and there are cathode fixed connection holes 14 every 1 cm to facilitate the connection of the temperature test thermocouple cathode wire 5. The purpose of this setting is to ensure that the temperature measurement point of the box-type resistance furnace is at the center of the box-type resistance furnace body, and a temperature measurement point is formed at this point. The cathode fixed connection hole 14 is formed by winding the temperature test thermocouple anode wire 4.

[0172] The temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 are interchangeable.

[0173] The temperature test thermocouple cathode wire 5 is made of common thermocouple cathode material, one end of which is connected to the temperature test thermocouple anode wire 4 cathode fixed connection hole 14, and the other end is led out of the furnace body through the box-type resistance furnace door. The connection point between the cathode wire 5 and the anode wire 4 is the temperature test point.

[0174] The thermocouple protection film 6 is made of high temperature resistant insulating materials such as asbestos, and is used to protect the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 from passing through the box-type resistance furnace door, and at the same time, it plays the role of insulating the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 from the box-type resistance furnace door. The thermocouple protection film 6 is only set at the contact between the tested box-type resistance furnace door and the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5.

[0175] The compensation wire 7 is used to connect the temperature data acquisition and recording device 8 with the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5. The anode of the compensation wire 7 and the temperature test thermocouple anode wire 4 are made of the same material, and the cathode of the compensation wire 7 and the temperature test thermocouple cathode wire 5 are made of the same material. The compensation wire 7 and the temperature test thermocouple anode wire 4 and the temperature test thermocouple cathode wire 5 are connected by a socket, and the compensation wire 7 and the temperature data acquisition and recording device 8 are connected by a socket.

[0176] The temperature data acquisition and recording device 8 collects temperature data and performs calculations. During the box-type resistance furnace heating energy efficiency test, after the maximum operating temperature of the box-type resistance furnace is input, the temperature data acquisition and recording device 8 determines whether the temperature of the geometric center point of the box-type resistance furnace body collected reaches the maximum operating temperature of the box-type resistance furnace within the range of ±5°C. If it reaches it, the temperature has reached the signal. During the box-type resistance furnace constant temperature energy efficiency test, after the maximum operating temperature of the box-type resistance furnace is input, after the box-type resistance furnace reaches the maximum operating temperature of the box-type resistance furnace within the range of ±5°C, the temperature has reached the signal, and then continue to judge whether the temperature inside the box-type resistance furnace is within the corresponding operating temperature range (±5°C of the maximum operating temperature). If it exceeds the range, the temperature exceeds the range signal is output.

[0177] The energy consumption test device 2 includes an energy consumption test device 9 , a control module 10 and a connecting wire 11 .

[0178] The control module 10 communicates with the temperature data acquisition and recording device 8 and the energy consumption test equipment 9 by software connection, and the energy consumption test equipment 9 is connected to the tested box-type resistance furnace by a connecting wire 11 .

[0179] Based on the above device, the present invention also proposes a laboratory box-type resistance furnace energy efficiency test method.

[0180] Box furnace working status: based on the following test conditions:

[0181] During the energy efficiency test, the box furnace should remain unloaded and meet the following requirements:

[0182] 1. The accessories that are intended to be connected to the box-type furnace to ensure the normal operation of the box-type furnace should be installed and connected according to the installation requirements of the instruction manual;

[0183] 2. For box-type furnaces that are used for the first time or have not been used for a long time, the furnace needs to be dried according to the requirements of the manufacturer's product manual;

[0184] 3. The door of the box furnace should be kept completely closed;

[0185] 4. Open the door of the box-type furnace and leave it vacant for at least 2 hours to make the temperature inside the box-type resistance furnace consistent with the ambient temperature;

[0186] 5. For box-type resistance furnaces equipped with fans, the fans should operate normally during the test.

[0187] 6. This method is applicable to the energy efficiency test of box-type resistance furnaces for natural atmosphere and protective atmosphere experiments with working temperatures between 100°C and 1600°C. During the energy efficiency test of box-type resistance furnaces for protective atmosphere experiments, the corresponding protective gas needs to be introduced.

[0188] Measurement of working area: Use a steel tape measure to measure the geometric shape of the working area of ​​the box-type furnace according to 7.3.2 of JJF 1376-2012. The result is the working area of ​​the box-type furnace, which is represented by V.

[0189] Measurement of geometric center temperature: Place the temperature measuring probe of the temperature measuring device at the geometric center of the box furnace and test the temperature every 3 minutes. For the geometric center, see 6.3.1.3 of GB / T28849-2012.

[0190] Box furnace test temperature: Set the box furnace test temperature to the highest operating temperature.

[0191] Empty furnace heating test: The box furnace should be fully dried before the test. Connect the power supply when the furnace is cold and empty, and heat it to the highest operating temperature at the maximum temperature change rate. Record the starting and ending temperatures of the geometric center point, and the power consumption E in the temperature rise range. 1 , heating time T.

[0192] Constant temperature test: After the temperature of the geometric center of the box furnace is set to the maximum operating temperature within ±5°C, maintain the thermal stability for 2 hours, and record the power consumption in the next hour. 2 express.

[0193] The energy efficiency test method of the box-type resistance furnace for laboratory use specifically includes the following steps:

[0194] 1. Box-type resistance furnace empty furnace heating energy efficiency test method:

[0195] 1. Measure the volume of the working area of ​​the box-type resistance furnace, represented by V; select a suitable support rod 13 according to the size of the resistance furnace box, and then build a temperature test bracket 3 to determine the geometric center position of the box-type resistance furnace: select one of the temperature test thermocouple cathode wires 5 to connect to the cathode fixed connection hole 14 of the temperature test thermocouple anode wire 4, and the cathode fixed connection hole 14 is located at the geometric center position of the box-type resistance furnace box. The connection point between the temperature test thermocouple cathode wire 5 and the temperature test thermocouple anode wire 4 is the temperature test point;

[0196] Step 2. Place the temperature probe of the box-type resistance furnace temperature test device 1 at the geometric center of the box-type resistance furnace through the box-type resistance furnace temperature test bracket 3; connect the standard temperature measuring material 15 to the connecting wire 16, and the standard temperature measuring material 15 is located at the geometric center of the box-type resistance furnace;

[0197] Step 3. Introduce protective gas at rated flow rate, stabilize for 30 minutes, and continue to introduce it during the subsequent test process;

[0198] Step 4. Set the test temperature of the box-type resistance furnace to the highest operating temperature;

[0199] Step 5. The box-type resistance furnace has been fully dried before the test. When the furnace is cold and empty, the power supply is connected to heat it to the highest operating temperature at the maximum temperature change rate. After the test begins, the energy consumption test device 2 starts working and records the starting and ending temperatures of the geometric center point and the power consumption E in the temperature rise range. 1 , heating time T;

[0200] Step 6. As the temperature rises, when the standard temperature measuring material 15 melts and breaks, the current loop formed by the standard temperature measuring material 15, the connecting wire 16 and the control module 10 is disconnected, and the energy consumption test device 9 stops recording the power consumption, and the starting temperature and ending temperature of the geometric center point and the power consumption E1 in the temperature rise range are obtained; at the same time, the actual measured temperature t at the geometric center position of the box-type resistance furnace at this time is measured by the thermocouple 3 ; According to the standard temperature measurement material 15 inherent melting point temperature t 2 The calculations are shown in formula (1) and formula (2), and the empty furnace heating efficiency is further calculated;

[0201] C 1 =E 1 / [(t 2 -t 1 )·c·V×ρ] (1)

[0202] v=(t 2 -t 1 ) / T (2)

[0203] Where:

[0204] C 1 ——Energy efficiency under empty furnace heating test, unit is 1;

[0205] E 1 ——Power consumption under empty furnace heating test, in joule (J);

[0206] t 1 ——The starting temperature of the empty furnace heating test, in degrees Celsius (℃);

[0207] t 2 ——The end temperature of the empty furnace heating test, in degrees Celsius (℃);

[0208] c——Specific heat capacity of air at the initial temperature under standard atmospheric pressure, in joules per kilogram Celsius (J / (kg·℃));

[0209] V——Box furnace working area, in cubic meters (m 3 );

[0210] r——Air density at the starting temperature under standard atmospheric pressure, in kilograms per cubic meter (kg / m 3 );

[0211] v——Temperature change rate during the empty furnace heating process, in degrees Celsius per minute (℃ / min);

[0212] T——empty furnace heating test time, in minutes (min).

[0213] The specific heat capacity of air at 23°C under standard atmospheric pressure is 1.004 kJ / (kg·°C), and the air density is 1.193 kg / m 3 .

[0214] V = V1-V2, V1 is the volume of the box-type furnace body, V2 is the volume of the insulation layer of the box-type furnace door;

[0215] The reliability of the test process is determined by the formula (3) and compared with the actual measured temperature t 3 and the inherent melting point temperature t of the standard temperature measuring material 2 , determine the reliability of the temperature rise test. When formula (3) holds true, the test is reliable and the data is available;

[0216] Formula (3)(t 3 -10)≤t 2 ≤(t 3 +10).

[0217] 2. Box-type resistance furnace empty furnace constant temperature energy efficiency test method:

[0218] 1. Measure the volume of the working area of ​​the box-type resistance furnace, represented by V; select a suitable support rod 13 according to the size of the resistance furnace box, and then build a temperature test bracket 3 to determine the geometric center position of the box-type resistance furnace: select one of the temperature test thermocouple cathode wires 5 to connect to the cathode fixed connection hole 14 of the temperature test thermocouple anode wire 4, and the cathode fixed connection hole 14 is located at the geometric center position of the box-type resistance furnace box. The connection point between the temperature test thermocouple cathode wire 5 and the temperature test thermocouple anode wire 4 is the temperature test point;

[0219] 2. Place the temperature probe of the box-type resistance furnace temperature test device 1 at the geometric center of the box-type resistance furnace through the box-type resistance furnace temperature test bracket 3, and test the temperature every 3 minutes;

[0220] 3. Introduce protective gas at rated flow rate, stabilize for 30 minutes, and continue to introduce it during the subsequent test;

[0221] 4. After the test starts, the temperature measured by the temperature measuring device reaches the set maximum operating temperature within ±5°C, and the thermal stability is maintained for 2 hours. When the temperature data acquisition and recording device 8 outputs the temperature reaching signal, the energy consumption test device 2 starts working and records the power consumption for the next 1 hour. 2 express.

[0222] 5. After 1 hour, the energy consumption test device 2 stops recording and further calculates the energy efficiency of the empty furnace at constant temperature. In this process, if the temperature data acquisition and recording device 8 outputs a signal indicating that the temperature is out of range, the energy consumption recording is stopped and an abnormal alarm is issued.

[0223] Calculate the constant temperature energy efficiency. See formula (4) for the constant temperature energy efficiency calculation.

[0224] C 2 =E 2 / V (4)

[0225] Where:

[0226] C 2 ——Energy efficiency of constant temperature test, in joules per cubic meter (J / m 3 );

[0227] E 2 ——power consumption of constant temperature test, in joule (J);

[0228] V——Box furnace working area, in cubic meters (m 3 ); V = V1-V2, V1 is the volume of the box-type furnace body, and V2 is the volume of the insulation layer of the box-type furnace door.

[0229] References

[0230] 1. Qi Yue, He Liu, Xia Ziyuan. Research and exploration on safety standards and sustainable development of university laboratories[J]. Experimental Technology and Management, 2021, 38(01): 276-277+281.

[0231] 2. Mao Runhui, Huang Kuigang, Zhang Yongwu, Xue Yuanqiang. Development of national standards for energy consumption classification of resistance furnaces and research on key technical indicators [A]. China Standardization Association. Standardization promotes supply-side structural reform and innovation - Proceedings of the 13th China Standardization Forum [C]. China Standardization Association: China Standardization Association, 2016: 8.

[0232] 3. Zhao J, Ma L, Zayed ME, et al. Industrial reheating furnaces: A review of energy efficiency assessments, waste heat recovery potentials, heating process characteristics and perspectives for steel industry [J]. Process Safety and Environmental Protection, 2021.

[0233] 4. General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China, Administration of Standardization of the People’s Republic of China, GB / T30839.4-2015 “Energy Consumption of Industrial Electric Heating Devices Part 4: Resistance Furnaces” [S]. Beijing: China Standards Press, 2015

[0234] 5. General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China, Administration of Standardization of the People’s Republic of China, GB / T39476-2020 Test Method for Energy Efficiency of Pharmaceutical Stability Test Chambers[S]. Beijing: China Standards Press, 2020.

[0235] The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the inventive concept, changes and advantages that can be thought of by those skilled in the art are included in the present invention and are protected by the attached claims.

Claims

1. A box-type resistance furnace energy efficiency test device for laboratory use, characterized in that: It comprises a box-type resistance furnace temperature testing device (1) and an energy consumption testing device (2); The box-type resistance furnace temperature testing device (1) comprises a box-type resistance furnace temperature testing bracket (3), a temperature testing thermocouple anode wire (4), a temperature testing thermocouple cathode wire (5), a thermocouple protective film (6), a compensation wire (7), a temperature data acquisition and recording device (8), a standard temperature measuring material (15), and a first connecting wire (16); wherein: The temperature testing thermocouple anode wire (4) is made of common thermocouple anode material, and has cathode fixing connection holes (14) every 1 cm, and the cathode fixing connection holes (14) are formed by winding the temperature testing thermocouple anode wire (4); The common galvanic anode materials include nickel-chromium or platinum-rhodium 10; The temperature test thermocouple anode wire (4) is physically connected to the box-type resistance furnace temperature test bracket (3), one end of the temperature test thermocouple anode wire (4) is connected to the base (12) of the box-type resistance furnace temperature test bracket (3), and the other end is passed through the fixing hole of the support rod (13) and then led out of the furnace body through the box-type resistance furnace door; The compensation wire (7) is used to connect the temperature data acquisition and recording device (8) with the temperature test thermocouple anode wire (4) and the temperature test thermocouple cathode wire (5); the anode of the compensation wire (7) and the temperature test thermocouple anode wire (4) are made of the same material; the cathode of the compensation wire (7) and the temperature test thermocouple cathode wire 5 are made of the same material; the compensation wire (7) and the temperature test thermocouple anode wire (4) and the temperature test thermocouple cathode wire (5) are connected by a socket; the compensation wire (7) and the temperature data acquisition and recording device (8) are connected by a socket; the two ends of the standard temperature measuring material (15) are connected to the first connecting wire (16); the first connecting wire (16) and the control module (10) are electrically connected; the standard temperature measuring material (15), the first connecting wire (16) and the control module (10) form a current loop; The temperature data acquisition and recording device (8) acquires temperature data and performs calculations; during the box-type resistance furnace heating energy efficiency test, the corresponding standard temperature measuring material (15) is selected according to the maximum working temperature of the box-type resistance furnace, and when the standard temperature measuring material (15) melts and breaks, the current loop formed by the standard temperature measuring material (15), the first connecting wire (16) and the control module (10) is disconnected; during the box-type resistance furnace constant temperature energy efficiency test, after the maximum working temperature of the box-type resistance furnace is input, the temperature data acquisition and recording device (8) determines whether the collected temperature of the geometric center point of the box-type resistance furnace body reaches the maximum working temperature of the box-type resistance furnace within ±5°C. If so, a temperature reaching signal is output, and then the temperature in the box-type resistance furnace is continuously determined to be within the corresponding working temperature range, that is, ±5°C of the maximum working temperature. If it exceeds the range, a temperature exceeding range signal is output; The energy consumption test device (2) comprises an energy consumption test device (9), a control module (10) and a second connecting wire (11); The standard temperature measuring substance (15) is made of pure metal or alloy material with high and stable melting point, including pure gold, pure copper or brass H62. The first connecting wire (16) is connected to the standard temperature measuring substance (15), and is physically connected to the box-type resistance furnace temperature test bracket (3) through the fixing hole of the support rod (13), and is led out of the furnace body through the box-type resistance furnace door; the compensation wire (7) is made of high-temperature resistant pure metal or alloy material, including pure platinum or nickel silicon, and the melting point of the material must be higher than the melting point of the standard temperature measuring substance (15); during the test, the standard temperature measuring substance (15) is ensured to be at the geometric center position of the box-type resistance furnace body by adjusting the size of the support rod (13), the position of the box-type resistance furnace temperature test bracket (3), and the length and position of the compensation wire (7).

2. The laboratory box-type resistance furnace energy efficiency testing device according to claim 1, characterized in that: The box-type resistance furnace temperature testing device (1) is electrically connected to the energy consumption testing device (2).

3. The laboratory box-type resistance furnace energy efficiency testing device according to claim 1, characterized in that: The box-type resistance furnace temperature test bracket (3) is made of high-temperature resistant insulating material and is composed of a base (12) and at least two support rods (13), wherein the support rods (13) are inserted into the base (12) and fixed.

4. The laboratory box-type resistance furnace energy efficiency testing device according to claim 1, characterized in that: The temperature test thermocouple cathode wire (5) is made of common thermocouple cathode material, one end of which is connected to the cathode fixed connection hole (14) of the temperature test thermocouple anode wire (4), and the other end is led out of the furnace body through the furnace door of the box-type resistance furnace; the temperature test thermocouple anode wire (4) and the temperature test thermocouple cathode wire (5) are interchangeable; Common galvanic cathode materials include nickel silicon or pure platinum.

5. The laboratory box-type resistance furnace energy efficiency testing device according to claim 1, characterized in that: The thermocouple protection film (6) is made of high temperature resistant insulating material and is arranged at the contact point between the door of the box-type resistance furnace to be tested and the temperature test thermocouple anode wire (4) and the temperature test thermocouple cathode wire (5); the connection point between the temperature test thermocouple cathode wire (5) and the temperature test thermocouple anode wire (4) is the temperature test point.

6. The laboratory box-type resistance furnace energy efficiency testing device according to claim 1, characterized in that: The control module (10) communicates with the temperature data acquisition and recording device (8) and the energy consumption test equipment (9) using software connection, and the energy consumption test equipment (9) is connected to the tested box-type resistance furnace via a second connecting wire (11).

7. A laboratory box-type resistance furnace heating energy efficiency test method based on the laboratory box-type resistance furnace energy efficiency test device according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step 1: Measure the volume of the working area of ​​the box-type resistance furnace, represented by V; select a support rod (13) according to the size of the resistance furnace box to build a box-type resistance furnace temperature test bracket (3), and determine the geometric center position of the box-type resistance furnace: select a temperature test thermocouple cathode wire (5) to connect through the temperature test thermocouple anode wire (4) cathode fixed connection hole (14), and the cathode fixed connection hole (14) is located at the geometric center position of the box-type resistance furnace box; the connection point of the temperature test thermocouple cathode wire (5) and the temperature test thermocouple anode wire (4) is the temperature test point; the first connecting wire (16) is connected to the control module (10); Step 2. Place the temperature measuring probe of the box-type resistance furnace temperature testing device (1) at the geometric center of the box-type resistance furnace through the box-type resistance furnace temperature testing bracket (3); connect the standard temperature measuring material (15) to the first connecting wire (16), and the standard temperature measuring material (15) is located at the geometric center of the box-type resistance furnace; Step 3. Introduce protective gas at rated flow rate, stabilize for 30 minutes, and continue to introduce it during the subsequent test process; Step 4. Set the test temperature of the box-type resistance furnace to the highest operating temperature; Step 5. The box-type resistance furnace has been fully dried before the test. When the furnace is in an empty and cold state, the power supply is connected and the temperature is raised to the maximum operating temperature at the maximum temperature change rate. After the test begins, the energy consumption test device (2) starts working and records the starting and ending temperatures of the geometric center point, the power consumption E1 in the temperature rise range, and the heating time T. Step 6. As the temperature rises, when the standard temperature measuring material (15) melts and breaks, the current loop formed by the standard temperature measuring material (15), the first connecting wire (16) and the control module (10) is disconnected, and the energy consumption test device (9) stops recording the power consumption, and the starting temperature and ending temperature of the geometric center point and the power consumption E1 in the temperature rise range are obtained; at the same time, the actual temperature t3 of the geometric center position of the box-type resistance furnace at this time is measured by a thermocouple; according to the inherent melting point temperature t2 of the standard temperature measuring material (15), the calculation is shown in formulas (1) and (2), and the empty furnace heating energy efficiency is further calculated; The formula (1) is C1=E1 / [(t2-t1)×c×V×r]; The formula (2) is v = (t2 - t1) / T; Where C1 is the energy efficiency under the empty furnace heating test, the unit is 1; E1 is the power consumption under the empty furnace heating test, the unit is joule; t1 is the starting temperature of the empty furnace heating test, the unit is Celsius; t2 is the inherent melting point temperature of the standard temperature measuring material, the unit is Celsius; c is the specific heat capacity of the protective gas at the starting temperature under standard atmospheric pressure, in joules per kilogram of Celsius; V is the working area of ​​the box furnace, in cubic meters; r is the density of the protective gas at the starting temperature under standard atmospheric pressure, in kilograms per cubic meter; v is the temperature change rate of the empty furnace heating process, in degrees Celsius per minute; T is the empty furnace heating test time, in minutes; V = V1-V2, V1 is the volume of the box-type furnace body, V2 is the volume of the insulation layer of the box-type furnace door; The reliability of the test process is determined by using the formula (3), and the actual measured temperature t3 of the box is compared with the inherent melting point temperature t2 of the standard temperature measurement material to determine the reliability of the temperature rise test. When the formula (3) is established, the test is reliable and the data is available. Formula (3)(t3-10)≤t2≤(t3+10).

8. A method for testing the energy efficiency of a box-type resistance furnace at a constant temperature in a laboratory based on the box-type resistance furnace energy efficiency testing device in a laboratory as claimed in any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step 1. Measure the volume of the working area of ​​the box-type resistance furnace, represented by V; select a support rod (13) according to the size of the resistance furnace box to build a box-type resistance furnace temperature test bracket (3), and determine the geometric center position of the box-type resistance furnace: select a temperature test thermocouple cathode wire (5) to connect through the temperature test thermocouple anode wire (4) cathode fixed connection hole (14), and the cathode fixed connection hole (14) is located at the geometric center position of the box-type resistance furnace box; the connection point between the temperature test thermocouple cathode wire (5) and the temperature test thermocouple anode wire (4) is the temperature test point; Step 2. Place the temperature probe of the box-type resistance furnace temperature test device (1) at the geometric center of the box-type resistance furnace through the box-type resistance furnace temperature test bracket (3), and test the temperature every 3 minutes; Step 3. Introduce protective gas at rated flow rate, stabilize for 30 minutes, and continue to introduce it during the subsequent test process; Step 4. After the test starts, the temperature measured by the temperature measuring device reaches the set maximum operating temperature within the range of ±5°C, and the thermal stability is maintained for 2 hours. When the temperature reaching signal output by the temperature data acquisition and recording device (8) is received, the energy consumption test device (2) starts working and records the power consumption for the next hour, which is represented by E2; Step 5.1h later, the energy consumption test device (9) stops recording, and further calculates the energy efficiency of the empty furnace at constant temperature; During this process, if a signal indicating that the temperature is out of range is received from the temperature data acquisition and recording device (8), the energy consumption recording is stopped and an abnormal alarm is issued; Calculate the constant temperature energy efficiency. See formula (4) for the constant temperature energy efficiency calculation. The formula (4) is C2=E2 / V; Among them, C2 is the energy efficiency of the constant temperature test, in joules per cubic meter; E2 is the power consumption of the constant temperature test, in joules; V is the working area of ​​the box furnace, in cubic meters; V=V1-V2, V1 is the volume of the box furnace body, and V2 is the volume of the insulation layer of the box furnace door.

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