Temperature detection device for electrical element of alloy melting furnace

Abstract

The utility model relates to the field of electrical element temperature detection. A temperature detection device for electrical elements of an alloy melting furnace comprises a patch type thermal resistor 1, a normally open relay 2, a digital quantity output template and a PLC which are installed on each electrical element, each patch type thermal resistor comprises a first power supply input connector 12, a second power supply input connector 13 and a temperature signal connector 11, all the temperature signal connectors are connected in series and then connected to the PLC, and the PLC is connected with the normally open relay 2. A normally-open relay control line connector 21 of the normally-open relay 2 is connected with a digital quantity output template, the digital quantity output template is connected with a PLC, the normally-open relay 2 comprises a relay set A and a relay set B, and a first power input connector 12 of each patch type thermal resistor is connected to a contact of a normally-open contact of the relay set A.

Description

TECHNICAL FIELD

[0001] The utility model relates to electrical component temperature detection field. BACKGROUND

[0002] The alloy melting furnace is an important furnace equipment for low-cost smelting stainless steel in steel enterprises, and the voltage frequency conversion device is a core part. Because of large current, various power components generate serious heat, and cooling water cooling is usually used to cool them, and the temperature directly affects the service life and voltage withstand parameters of the components, and once the temperature is too high, breakdown is easy to occur, causing production stagnation. The thermal resistance detects the temperature through the linear change of resistance value and temperature, and the temperature detection is realized through the measurement of resistance value by the template, which is a commonly used temperature detection method. The intermediate frequency furnace has nearly 200 electric devices such as reactors and capacitors, which all need to measure the temperature, and at present, the personnel inspection method is usually used, the real-time performance cannot be guaranteed, and due to the safety risks such as capacitor breakdown and explosion, personnel detection is carried out when the furnace is stopped, and the temperature state of the equipment during operation cannot be grasped. CONTENT OF THE UTILITY MODEL

[0003] The utility model wants to solve the technical problem of how to provide a kind of alloy melting furnace electrical component temperature detection device of convenient inspection.

[0004] The utility model wants to solve the technical problem of a kind of alloy melting furnace electrical component temperature detection device, including the patch type thermal resistance 1, normally open relay 2, digital output template and PLC installed on each electrical component, each patch type thermal resistance includes first power input connector 12, second power input connector 13 and temperature signal connector 11, all temperature signal connectors are connected to PLC after being connected in series, the normally open relay control line connector 21 of normally open relay 2 is connected digital output template, the digital output template is connected PLC, the normally open relay 2 includes group A relay and group B relay, the first power input connector 12 of each patch type thermal resistance is connected to one contact of a group of normally open contacts of group A relay, another contact of the group of normally open contacts is connected to one end of power supply, the second power input connector 13 of each patch type thermal resistance is connected to one contact of a group of normally open contacts of group B relay after being grouped and connected in parallel, another contact of the group of normally open contacts is connected to another end of power supply.

[0005] The normally open relay 2 is a normally open relay with four groups of normally open contacts, and the second power input connector 13 of each patch type thermal resistance is grouped, and every four second power input connectors form a group.

[0006] When the number of electrical elements is divisible by 4, the number of A group relays is the number of electrical elements divided by 4, when the number of electrical elements is not divisible by 4, the number of A group relays is the number of electrical elements divided by 4 plus 1; when the number of A group relays is divisible by 4, the number of B group relays is the number of A group relays divided by 4, when the number of A group relays is not divisible by 4, the number of B group relays is the number of A group relays divided by 4 plus 1.

[0007] The beneficial effects of the utility model are: 1. realizing comprehensive detection of the temperature of various electrical equipment of an alloy melting furnace; 2. realizing the function of detecting multiple signals by a single channel of a template by using a relay matrix (A group relays and B group relays); 4. the temperature of each element can be displayed respectively and early warning can be performed by a program and an HMI picture; 5. a detection frequency adjustment program is set, and the detection frequency of important equipment and facilities and components with higher temperature is increased according to needs and state changes; 6. the purpose of low-cost high-efficiency large-scale temperature detection is realized by the device. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is the circuit schematic diagram of the embodiment 1 of the utility model;

[0009] Figure 2 is the external connection joint schematic diagram of the surface mount type thermal resistance;

[0010] Figure 3 is the external connection joint schematic diagram of the normally open relay;

[0011] Figure 4 is the normally open relay circuit principle schematic diagram;

[0012] Among them, 1, surface mount type thermal resistance, 2, normally open relay, 11, temperature signal joint, 12, first power input joint, 13, second power input joint, 21, normally open relay control line joint, 22, normally open contact. DETAILED DESCRIPTION

[0013] A certain alloy melting furnace has 32 electrical elements (including electric reactors, capacitors and the like) needing to measure the temperature, and in order to complete the temperature measurement of the electrical elements of the device, 32 surface mount type thermal resistances PT100, 10 normally open relays with four groups of normally open contacts, a plurality of wires, a digital quantity output template (a plurality of digital quantity output templates can also be used) and a PLC are purchased, the joint of each surface mount type thermal resistance PT100 has a power input joint (two positive and negative) and a temperature signal joint 11, each normally open relay 2 has four groups of normally open contacts 22 and a normally open relay control line joint 21, the normally open relay control line joint is used for controlling the opening and closing of the normally open relay control line (for example, when the temperature signal is lower than the set value, the normally open relay control line joint is connected to the normally open relay control line, and the normally open contact is closed, when the temperature signal is higher than the set value, the normally open relay control line joint is disconnected from the normally open relay control line, and the normally open contact is opened), and the PLC is connected to the temperature signal joint 11 and the normally open relay control line joint 21. Figure 4As shown, the four sets of normally open contacts of the normally open relay are arranged in parallel. When the normally open relay control line connector controls the normally open relay control circuit to be on or off, the four sets of normally open contacts are simultaneously on or off. The normally open relay is a commonly used relay that can be purchased directly from the market. Each PT100 surface mount RTD is attached to the component to be tested, and then its temperature signal connector is connected to the PLC. The digital output module is also connected to the PLC.

[0014] like Figures 1-3 As shown, ten normally open relays with four sets of normally open contacts are divided into two groups: Group A has eight relays, and Group B has two relays. The normally open relay control line connector 21 of each normally open relay is connected to a digital output module (one control signal contact). The positive terminal of each surface-mount RTD PT100 is connected to one connector of one set of normally open contacts in Group A relays, and the other normally open contact is connected to the positive terminal of the power supply. The negative terminals of each surface-mount RTD PT100 are grouped into groups of four and connected together. These groups are then connected to one connector of one set of normally open contacts in Group A relays of Group B relays, and the other normally open contact is connected to the negative terminal of the power supply.

[0015] Note that each control signal contact of the digital output module is connected to only one control line (temperature signal connector of PT100 surface mount RTD or control line connector of normally open relay).

[0016] When it is necessary to check the temperature of electrical components of electrical equipment, the PLC controls one set of normally open contacts of a relay in group A to close, and simultaneously controls one set of normally open contacts of a relay in group B to close (the relays in group A need to be connected to the relays in group B). At this time, the temperature of an electrical component is detected by a surface-mount RTD PT100. The PLC controls the relays in group A and group B to sequentially complete the temperature check of all electrical components of electrical equipment.

[0017] The above embodiment only measures the temperature of 32 electrical components. In reality, a medium-frequency furnace has nearly 200 electrical components such as reactors and capacitors, all of which require temperature measurement. Existing technologies mostly rely on personnel inspections, which cannot guarantee real-time performance. Furthermore, due to safety risks such as capacitor breakdown and explosion, personnel inspections are conducted only when the furnace is shut down, making it impossible to monitor the temperature status of the equipment during operation. The following explanation uses 200 electrical components as an example.

[0018] The 200 electrical components require 200 surface-mount RTDs (PT100), 50 Group A relays, and 7 Group B relays. All relays are normally open relays with four sets of normally open contacts. The digital output module uses a module with 28 signal connectors. Each PT100 is attached to the component to be monitored, and their temperature signal connectors are all connected to a common connector on the PLC. The digital output module is then connected to the PLC.

[0019] The normally open relay control line connector of each normally open relay is connected to the digital output module (one control signal contact). Connect the positive terminal of each PT100 surface mount RTD to one connector of a set of normally open contacts of group A relays; connect the other normally open contact of each PT100 to the positive terminal of the power supply. Group the negative terminals of each PT100 into sets of four and connect them together. Then connect these groups to one connector of a set of normally open contacts of group A relays of group B relays; connect the other normally open contact of each group to the negative terminal of the power supply.

[0020] When it is necessary to check the temperature of electrical components of electrical equipment, the PLC controls one set of normally open contacts of a relay in group A to close, and simultaneously controls one set of normally open contacts of a relay in group B to close (the relays in group A need to be connected to the relays in group B). At this time, the temperature of an electrical component is detected by a surface-mount RTD PT100. The PLC controls the relays in group A and group B to sequentially complete the temperature check of all electrical components of electrical equipment.

[0021] Each test only requires activating one relay from group A and one from group B to achieve a 50*7 matrix detection, enabling the separate detection of 200 RTD signals. Assuming a maximum detection time of one signal per second (actual detection time is very fast, reaching 0.1 seconds per signal), testing one group of components takes only about 3 minutes. 200 signals are detected using 57 relays (one digital output module has 32 control signals, requiring only two modules). The PLC program cyclically controls the relays to read the RTD temperature, creating an HMI screen for temperature display and alarm settings. Besides judging normal temperature readings, the PLC program also judges temperature change trends, autonomously calculating and adjusting the relay detection frequency according to set rules to increase the detection frequency of signals from key equipment or those with significant temperature changes, ensuring timely detection. Utilizing the module's characteristics (each channel has two positive and two negative signals) to further divide the signal wiring into two groups, the number of analog channels used can be reduced by half. Compared to the original testing solution, the junction box can be placed closer to the site, requiring only the relay control line and one set of main signal lines to be routed back.

[0022] This utility model device has been tested on the alloy melting furnace of the No. 2 steelmaking plant of Taiyuan Iron & Steel Group (TISCO) at position #5. Thermocouples are attached to the components, and short-distance wiring is routed to the local box with a relay control matrix. The control lines and summary signal lines are then laid inside the control cabinet, thus reducing both the number of components and the amount of wiring, thereby lowering costs. The real-time temperature of the components is displayed on an HMI screen with short detection intervals.

Claims

1. A temperature detection device for electrical components of an alloy melting furnace, characterized in that: The system includes a surface mount resistance thermometer (1), a normally open relay (2), a digital output module, and a PLC, all mounted on each electrical component. Each surface mount resistance thermometer includes a first power input connector (12), a second power input connector (13), and a temperature signal connector (11). All temperature signal connectors are connected in series to the PLC. The normally open relay control line connector (21) of the normally open relay (2) is connected to the digital output module, which is connected to the PLC. The normally open relay (2) includes a group of relays A and a group of relays B. The first power input connector (12) of each surface mount resistance thermometer is connected to one contact of a group of normally open contacts of the group of relays A. The other contact of the group of normally open contacts is connected to one end of the power supply. The second power input connector (13) of each surface mount resistance thermometer is connected in parallel to one contact of a group of normally open contacts of the group of relays B. The other contact of the group of normally open contacts is connected to the other end of the power supply.

2. The temperature detection device for electrical components of an alloy melting furnace according to claim 1, characterized in that: The normally open relay (2) is a normally open relay with four sets of normally open contacts. When the second power input connector (13) of each surface mount thermal resistor is grouped, every four second power input connectors are grouped together.

3. The temperature detection device for electrical components of an alloy melting furnace according to claim 2, characterized in that: When the number of electrical components divided by 4 is an integer, the number of relays in group A is the number of electrical components divided by 4. When the number of electrical components divided by 4 is not an integer, the number of relays in group A is the number of electrical components divided by 4 plus 1. When the number of relays in group A is an integer, the number of relays in group B is the number of relays in group A divided by 4. When the number of relays in group A is not an integer, the number of relays in group B is the number of relays in group A divided by 4 plus 1.

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