Temperature sensor online screening automatic switching device and furnace temperature control device

Abstract

The utility model provides a temperature sensor on-line screening automatic switching device and a furnace temperature control device. The switching device comprises a plurality of relays. Each temperature sensor is respectively connected in series with a switch end of a relay to form a plurality of branches, and the plurality of branches are connected in parallel and then connected with the temperature controller; the signal conditioning unit is connected with the temperature sensors and is used for converting the temperature analog quantity acquired by each temperature sensor into a temperature digital quantity; the comparator is connected with the signal conditioning unit and is used for comparing each temperature digital quantity with a furnace temperature set value at the current moment and outputting a comparison result; and the single chip microcomputer is respectively connected with the comparator and the control end of the relay, and is used for controlling the switch end of the relay corresponding to the selected temperature sensor to be connected according to the comparison result, and simultaneously controlling the switch ends of the relays corresponding to other temperature sensors to be disconnected.

Description

Technical Field

[0001] The utility model belongs to the technical field of quartz glass manufacturing equipment, and specifically relates to an online screening automatic switching device of a temperature sensor and a furnace temperature control device. Background Art

[0002] A high-temperature furnace is used in the quartz preparation process. Quartz products under this working condition have very high requirements for temperature accuracy. Therefore, two or more thermocouples are set to monitor the uniformity of the furnace temperature. Multiple thermocouples measure temperature, which provides the possibility of online switching of temperature control thermocouples. At the same time, choosing a suitable spare thermocouple has become the key to product scrapping.

[0003] The conventional method after a temperature-control thermocouple fails is to replace it with a new one online on site. This will cause the following problems: 1) There is a risk of high-temperature burns and process gas leakage; 2) On-site replacement of temperature-control thermocouples involves material preparation, on-site implementation and other steps, which is time-consuming. During this process, the furnace temperature is in an uncontrollable state and the product scrap rate is extremely high.

[0004] China's published patent application CN110901148A discloses a hot isostatic press control and standby automatic switching control system and control method, including a pressure vessel and a controller connected to the pressure vessel; the controller includes a temperature measurement signal input module connected to the pressure vessel, a central processing unit, and a temperature control signal output module, and the temperature measurement signal input module and the temperature control signal output module are respectively connected to the central processing unit; Siemens 1500 series PLC is used, which is costly and not conducive to large-scale use. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide an online screening automatic switching device for a temperature sensor and a furnace temperature control device, which can ensure the safety and constant temperature state during online replacement and have low cost.

[0006] The technical solution adopted by the utility model to solve the above technical problems is:

[0007] A temperature sensor online screening automatic switching device, wherein the temperature sensor is arranged in a high-temperature furnace to collect the temperature analog quantity in the furnace, and the temperature sensor is connected to a temperature controller; the switching device comprises:

[0008] A plurality of relays, each relay having a control end and a switch end; each of the temperature sensors is connected in series with a switch end of the relay to form a plurality of branches, and the plurality of branches are connected in parallel to the temperature controller;

[0009] A signal conditioning unit connected to the temperature sensor and used to convert the temperature analog quantity collected by each temperature sensor into a temperature digital quantity;

[0010] A comparator connected to the signal conditioning unit, used to compare each of the temperature digital quantities with the furnace temperature setting value at the current moment, and output the comparison result;

[0011] The single chip microcomputer is connected to the comparator and the control end of the relay respectively, and is used to control the switch end of the relay corresponding to the selected temperature sensor to be connected according to the comparison result, and to control the switch ends of the relays corresponding to other temperature sensors to be disconnected.

[0012] According to the above scheme, the signal conditioning unit includes a filtering module and an AD conversion module; wherein each temperature sensor is respectively connected to the input end of a filtering module, the output end of each filtering module is respectively connected to the input end of a path of the AD conversion module, and the output end of the corresponding path of the AD conversion module is respectively connected to the comparator.

[0013] According to the above solution, the signal conditioning unit further includes a signal amplification module, which is arranged between the output end of each filtering module and the input end of the AD conversion module.

[0014] According to the above scheme, the temperature sensor is a thermocouple.

[0015] According to the above solution, the output end of the AD conversion module is also connected to the single chip microcomputer.

[0016] According to the above scheme, the input end of the comparator is also connected to the single chip microcomputer for inputting the furnace temperature setting value at the current moment.

[0017] According to the above solution, the number of the output terminals of the comparator is the same as the number of the temperature sensors.

[0018] According to the above scheme, the temperature sensors are divided into several groups, one of which is a temperature control temperature sensor, and the other groups are standby temperature sensors.

[0019] According to the above scheme, the single chip microcomputer is of 91C52 series.

[0020] A furnace temperature control device comprises a temperature sensor, a temperature controller, and an online screening automatic switching device for the temperature sensor.

[0021] The beneficial effects of the utility model are as follows: the temperature analog quantity collected by the temperature sensor is converted into a temperature digital quantity that can be recognized by the comparator and the single-chip microcomputer through the signal conditioning unit. The comparator compares the temperature digital quantity collected by each temperature sensor with the preset temperature value. If the difference between the temperature digital quantity and the preset temperature value is within the range, it means that the temperature sensor has good performance, otherwise it means that the temperature sensor is faulty. The single-chip microcomputer selects a preset number of temperature sensors with good performance according to the result of the comparator, and connects the passage between the temperature sensor and the temperature controller by controlling the corresponding relay. The whole process is replaced online without opening the high-temperature furnace, avoiding the risk of high-temperature burns and process gas leakage; the switching time of the single-chip microcomputer through the relay is short, which does not affect the furnace temperature and product preparation; the single-chip microcomputer has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an embodiment of the utility model.

[0023] Figure 2 It is a schematic diagram of a local switching circuit according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0024] The utility model is further described below in conjunction with specific examples and drawings.

[0025] This embodiment provides a furnace temperature control device including a temperature sensor, an online screening automatic switching device for the temperature sensor, and a temperature controller.

[0026] The temperature sensor is arranged in the high temperature furnace to collect the temperature analog quantity in the furnace. In the furnace temperature control device of the high temperature furnace, a thermocouple is usually used as the temperature sensor, and other forms of temperature sensors can also be used.

[0027] like Figure 1 and Figure 2 As shown, the temperature sensor online screening automatic switching device includes several relays, a signal conditioning unit, a comparator and a single chip microcomputer. Each relay has a control end and a switch end; each temperature sensor is connected in series with a switch end of the relay to form several branches, and the several branches are connected in parallel to the temperature controller.

[0028] The signal conditioning unit is connected to the temperature sensor and is used to convert the temperature analog quantity collected by each temperature sensor into a temperature digital quantity that can be recognized by the comparator and the single-chip microcomputer. Specifically, the signal conditioning unit includes a filter module and an AD conversion module; wherein each temperature sensor is respectively connected to the input end of a filter module, the output end of each filter module is respectively connected to the input end of a path of the AD conversion module, and the output end of the corresponding path of the AD conversion module is respectively connected to the comparator. Preferably, the analog signal collected by some temperature sensors is weak, and a signal amplification module can be added, which is arranged between the output end of each filter module and the input end of the AD conversion module.

[0029] The comparator is connected to the signal conditioning unit, and is used to compare each of the temperature digital quantities with the furnace temperature setting value at the current moment, and output the comparison result. In this embodiment, the temperature digital quantity of each temperature sensor is compared with the furnace temperature setting value at the current moment. If the difference is within the preset threshold range, it means that the temperature sensor is in normal working state and outputs 1; otherwise, it means that the temperature sensor fails and outputs 0. This part is the normal function of the comparator. The furnace temperature setting value at the current moment can be input from other controllers or from the single-chip microcomputer of this switching device. In this embodiment, the single-chip microcomputer is connected to the input end of the comparator, and the furnace temperature setting value at the current moment is input.

[0030] The single-chip microcomputer is connected to the control end of the comparator and the relay, respectively, and is used to control the switch end of the relay corresponding to the selected temperature sensor to be connected according to the comparison result, and control the switch end of the relay corresponding to other temperature sensors to be disconnected. In this embodiment, the single-chip microcomputer identifies all 0 and 1 signals sent by the comparator, selects some temperature sensors corresponding to 1 as temperature control temperature sensors, and their relays are connected; other temperature sensors corresponding to 1 are used as spare temperature sensors, and their relays are disconnected; all temperature sensors corresponding to 0 are used as faulty temperature sensors, and their relays are disconnected. After the product is prepared, the faulty temperature sensor is replaced and used as a spare temperature sensor, and the cycle is repeated. In this way, abnormal phenomena of the temperature sensor during the temperature control process can be discovered early, and the spare temperature sensor can be switched to the temperature control temperature sensor in real time when the temperature control temperature sensor fails.

[0031] For example, in some embodiments, there are three thermocouples in total, of which thermocouple No. 1 is a temperature control thermocouple, and thermocouples No. 2 and No. 3 are standby thermocouples. When the high-temperature furnace is in continuous operation, when the comparator finds that thermocouple No. 1 is faulty and thermocouples No. 2 and No. 3 are normal, the switch terminals K1-1 and K1-2 of the corresponding relay K1 are controlled to be disconnected, and the switch terminals K2-1 and K2-2 of the relay K2 corresponding to thermocouple No. 2 are controlled to be connected. Thermocouple No. 3 is still used as a standby thermocouple, and the switch terminals K3-1 and K3-2 of the corresponding relay K3 are disconnected. After the high-temperature furnace stops working, open the high-temperature furnace, replace thermocouple No. 1, use thermocouple No. 1 as a standby thermocouple, and continue monitoring when the high-temperature furnace works next time.

[0032] Preferably, the output end of the AD conversion module is also connected to the single chip microcomputer to store the temperature digital value for other purposes.

[0033] In certain embodiments of the present invention, the number of the output terminals of the comparator is the same as the number of the temperature sensors. Furthermore, there may be one comparator for each temperature sensor, and each comparator needs to input the furnace temperature setting value at the current moment; the comparator may also be a multi-channel chip, which only needs to be able to complete the comparison of the temperature digital quantity of each temperature sensor with the furnace temperature setting value at the current moment, and output the corresponding results respectively.

[0034] For further optimization, the temperature sensors can be divided into several groups, one of which is a temperature control temperature sensor, and the other groups are standby temperature sensors. The single chip microcomputer can control the temperature sensors in groups.

[0035] This embodiment uses 91C52 or 89C52 series single chip microcomputer.

[0036] In this embodiment, except for the temperature sensor disposed in the high temperature furnace, all other devices are disposed in the central control room and connected to the temperature sensor through cables. Of course, a temperature sensor integrated with a signal conditioning unit can also be selected, so that the temperature sensor and the signal conditioning unit are integrated and disposed in the high temperature furnace, and all other devices are disposed in the central control room.

[0037] By adopting the device of the utility model, the temperature sensor can be replaced on-site in the central control room, avoiding the safety hazard of replacing the temperature sensor on-site; the single-chip microcomputer has low cost and can automatically screen out suitable spare thermocouples; the switching speed reaches microsecond level, and the furnace temperature is basically maintained unchanged.

[0038] It should be noted that the utility model protects the technical solution composed of the combination of hardware circuits. The single-chip microcomputer only controls the corresponding relay according to the signal (0 or 1) output by the comparator, and does not adopt a creative software algorithm. The corresponding relationship between the temperature sensor and the relay can be pre-set in the single-chip microcomputer, which does not require creative labor.

[0039] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to the utility model.

Claims

1. A temperature sensor online screening automatic switching device, wherein the temperature sensor is arranged in a high-temperature furnace to collect the temperature analog quantity in the furnace, and the temperature sensor is connected to a temperature controller; characterized in that: The switching device comprises: A plurality of relays, each relay having a control end and a switch end; each of the temperature sensors is connected in series with a switch end of the relay to form a plurality of branches, and the plurality of branches are connected in parallel to the temperature controller; A signal conditioning unit connected to the temperature sensor and used to convert the temperature analog quantity collected by each temperature sensor into a temperature digital quantity; A comparator connected to the signal conditioning unit, used to compare each of the temperature digital quantities with the furnace temperature setting value at the current moment, and output the comparison result; The single chip microcomputer is connected to the comparator and the control end of the relay respectively, and is used to control the switch end of the relay corresponding to the selected temperature sensor to be connected according to the comparison result, and to control the switch ends of the relays corresponding to other temperature sensors to be disconnected.

2. The temperature sensor online screening automatic switching device according to claim 1 is characterized in that: The signal conditioning unit includes a filtering module and an AD conversion module; wherein each temperature sensor is respectively connected to the input end of a filtering module, the output end of each filtering module is respectively connected to the input end of a path of the AD conversion module, and the output end of the corresponding path of the AD conversion module is respectively connected to the comparator.

3. The temperature sensor online screening automatic switching device according to claim 1 is characterized in that: The signal conditioning unit further comprises a signal amplification module, which is arranged between the output end of each filtering module and the input end of the AD conversion module.

4. The temperature sensor online screening automatic switching device according to claim 1 is characterized in that: The temperature sensor is a thermocouple.

5. The temperature sensor online screening automatic switching device according to claim 2 is characterized in that: The output end of the AD conversion module is also connected to the single chip microcomputer.

6. The temperature sensor online screening automatic switching device according to claim 1 is characterized in that: The input end of the comparator is also connected to the single chip microcomputer for inputting the furnace temperature setting value at the current moment.

7. The temperature sensor online screening automatic switching device according to claim 1 is characterized in that: The number of the output terminals of the comparator is the same as the number of the temperature sensors.

8. The temperature sensor online screening automatic switching device according to claim 1 is characterized in that: The temperature sensors are divided into several groups, one of which is a temperature control temperature sensor, and the other groups are standby temperature sensors.

9. The temperature sensor online screening automatic switching device according to claim 1, characterized in that: The single chip microcomputer is of 91C52 series.

10. A furnace temperature control device, characterized in that: It comprises a temperature sensor, a temperature controller, and the temperature sensor online screening automatic switching device as described in any one of claims 1 to 9.

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