Thermocouple acquisition cold end compensation structure

Abstract

The application discloses a cold end compensation structure for thermocouple acquisition, which is characterized by the following: an opening groove is designed, an isothermal block is arranged in the opening groove of each thermocouple connector, and the isothermal block is tightly combined with two conductive copper plates of each thermocouple connector through a heat-conducting silica gel sheet, so that the thermocouple connector of each input channel is tightly combined through the heat-conducting silica gel sheet, thereby avoiding the inconsistency of the temperature of two electrodes of the thermocouple and the temperature between multiple thermocouples, ensuring the real-time performance and accuracy of the cold end compensation, and meanwhile, the isothermal block is also tightly combined with an internal temperature compensation circuit sensor of a thermocouple acquisition system on a PCB through the heat-conducting silica gel sheet, the overall heat capacity of the cold end structure is improved, and the temperature sensitivity of the cold end to the outside is reduced. Meanwhile, the temperature plate is a circuit board on which a channel temperature sensor is arranged, the thickness of the circuit plate is a customized thickness, the channel temperature sensor is lifted to be close to the rear end of the conductive copper plate of the thermocouple connector, and the accuracy of temperature measurement is ensured. In addition, the heat-conducting silica gel sheet is a buffer for connecting each part, which ensures high thermal conductivity and insulation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thermocouple, more specifically, relates to a cold end compensation structure for thermocouple acquisition. BACKGROUND

[0002] The thermocouple sensor is a sensor for realizing temperature measurement based on thermoelectric effect, and its measurement principle is to combine the thermoelectric effect potential difference and the cold end compensation to obtain the measured temperature value.

[0003] For the temperature acquisition of the thermocouple sensor, the common cold end measurement methods include the freezing point method, the bridge compensation method, the integrated sensor compensation method and the temperature direct measurement method. The freezing point method needs an additional constant temperature device, which increases the system complexity and violates the portability of the instrument design. The bridge compensation method and the integrated sensor compensation method need to be matched with a compensation circuit for each type of thermocouple, and the structure is too complex. The temperature direct measurement method is suitable for the measurement of various types of thermocouples, which greatly reduces the complexity of the cold end compensation circuit.

[0004] The common cold end compensation structure for thermocouple acquisition based on the temperature direct measurement method is very simple, which only connects the temperature sensor and the cold end electrode of the thermocouple connector in contact. This method has the problems of long cold end temperature response time and being easily affected by external interference. At the same time, the temperature sensor is arranged on the pin of the thermocouple connector, and there is no obvious isothermal measure between the two electrodes of the thermocouple connector. The accuracy of the thermocouple acquisition principle is based on the premise that the temperatures of the two poles of the cold end node are equal. If the temperatures of the two poles are different, the thermocouple acquisition error will increase, which will affect the measurement accuracy. In addition, the position of the temperature sensor is on the pin of the thermocouple connector, which is far away from the actual cold end position, and there is no obvious design to enhance the heat conduction, which will cause the thermocouple cold end temperature to be not sensitive enough. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, and provides a cold end compensation structure for thermocouple acquisition to improve the cold end temperature response speed, reduce the sensitivity to external interference, realize the isothermal of the two poles, avoid affecting the measurement accuracy, and at the same time, enhance the sensitivity of the temperature sensor to the thermocouple cold end temperature.

[0006] To achieve the above-mentioned application purposes, the cold end compensation structure for thermocouple acquisition of the present application comprises:

[0007] Four thermocouple connectors are connected with four thermocouple sensors respectively, and the four thermocouple sensors are connected with the thermocouple collection system by being inserted into the corresponding thermocouple connectors, wherein the thermocouple connector is composed of a shell, two spring sheets, two conductive copper plates and two conductive copper screws, the shell has two sockets at the front end for inserting the spring sheets, the shell has two grooves at the rear end corresponding to the sockets, the two conductive copper plates are inserted into the corresponding grooves from the rear end to the front end and are pressed with the front end spring sheets, when the plug of the thermocouple connector is inserted, the two plugs of the thermocouple sensor are tightly attached to the conductive copper plate by the corresponding spring sheets; the groove is an open groove between the front end and the rear end on the upper side, the two conductive copper plates are exposed on the upper side of the open groove, and the rear end of the two conductive copper plates is connected with the screw hole on the PCB by the conductive copper screw, and the screw hole is connected with the thermocouple collection system;

[0008] An internal temperature compensation circuit sensor of the thermocouple collection system is installed on the PCB; an isothermal block is arranged in the open groove of each thermocouple connector and is tightly combined with the two conductive copper plates of each thermocouple connector through the heat-conducting silica gel sheet, and the isothermal block is tightly combined with the internal temperature compensation circuit sensor of the thermocouple collection system on the PCB through the heat-conducting silica gel sheet;

[0009] Four channel temperature sensors are temperature measuring devices in the cold end compensation structure and are responsible for the conversion of the temperature physical quantity and digital quantity of the two conductive copper plates of each thermocouple connector, i.e. the cold end;

[0010] Four temperature small plates are circuit boards for installing channel temperature sensors and are arranged below the rear end conductive copper plates of the four thermocouple connectors, one channel temperature sensor is arranged above each temperature small plate, and the channel temperature sensor is fixed on the PCB below the temperature small plate, the channel temperature sensor is connected with the thermocouple collection system on the PCB through the printed circuit on the temperature small plate, the thickness of the temperature small plate is a customized thickness, the channel temperature sensor is lifted to be close to the rear end of the conductive copper plate of the corresponding thermocouple connector, and the channel temperature sensor and the conductive copper plate are tightly combined through the heat-conducting silica gel sheet.

[0011] The purpose of the application is achieved.

[0012] The application discloses a cold end compensation structure for thermocouple acquisition, and relates to the technical field of thermocouple acquisition. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a structural schematic diagram of a specific embodiment of the cold end compensation structure for thermocouple acquisition,

[0014] Figure 2 is a front end partial enlarged structural schematic diagram of the cold end compensation structure for thermocouple acquisition shown in Figure 1

[0015] Figure 3 is a rear end partial enlarged structural schematic diagram of the cold end compensation structure for thermocouple acquisition shown in Figure 1

[0016] Figure 4 is an explosion view of the thermocouple connector in Figure 1 DETAILED DESCRIPTION

[0017] The specific embodiments of the application will be described below with reference to the accompanying drawings, so that those skilled in the art can better understand the application. It should be particularly noted that in the following description, when the detailed description of known functions and designs may obscure the main content of the application, these descriptions will be omitted here.

[0018] Figure 1 is a structural schematic diagram of a specific embodiment of the cold end compensation structure for thermocouple acquisition, Figure 2 , 3 ​​​Respectively are its front end, rear end structure diagram.

[0019] In this embodiment, as Figure 1 , 2 , 3 shows, the thermocouple acquisition cold end compensation structure, including four thermocouple connector 1, isothermal block 2, four channel temperature sensor 3( Figure 1 Due to the shielding, not drawn, see Figure 3 ), four temperature plate 4 and the internal temperature compensation circuit sensor 5 of thermocouple acquisition system.

[0020] Four thermocouple connector 1 is connected with four thermocouple sensor respectively, four thermocouple sensor is connected with thermocouple acquisition system through inserting corresponding thermocouple connector respectively, wherein, as Figure 4 Indicated, thermocouple connector 1 is composed of shell 101, two spring leaf 102, two pieces of conductive copper plate 103, two conductive copper screw 104, as Figure 4 Indicated, the front end of shell 101 has two sockets, respectively put into a spring leaf 102, the rear end of shell has two corresponding slots with two sockets, two pieces of conductive copper plate 103 are inserted from the rear end to the front end along the corresponding slot respectively, and are respectively pressed with the front spring leaf 102.

[0021] As Figure 2 Indicated, when the plug of thermocouple connector is inserted, the two plugs of thermocouple sensor are tightly adhered to the conductive copper plate 103 by corresponding spring leaf 102.The slot is an open slot A on the upper side between the front end and the rear end, and the upper side of the open slot of the two pieces of conductive copper plate 103 is exposed, and the rear end of the two pieces of conductive copper plate 103 is respectively connected with the screw hole on the PCB 6 by a conductive copper screw 104, and the screw hole is connected with the thermocouple acquisition system.

[0022] As Figure 1 Indicated, the internal temperature compensation circuit sensor 5 of thermocouple acquisition system is installed on the PCB 6.

[0023] As Figure 1 , 2 , 3 shows, isothermal block 2 is placed in the open slot A of each thermocouple connector 1, and is tightly combined with the two pieces of conductive copper plate 103 of each thermocouple connector 1 through the heat-conducting silica gel sheet, and the isothermal block 2 is tightly combined with the internal temperature compensation circuit sensor 5 of thermocouple acquisition system on the PCB 6 through the heat-conducting silica gel sheet.

[0024] As Figure 3 Indicated, four channel temperature sensor 3 is a temperature measuring device in the cold end compensation structure, and is respectively responsible for the temperature physical quantity and digital quantity conversion of the two pieces of conductive copper plate of four thermocouple connector 1, i.e. the cold end.

[0025] Four temperature plates 4 are circuit boards on which the channel temperature sensors 3 are installed, and are located below the rear ends of the conductive copper plates of the four thermocouple connectors 1. Above the temperature plates 4, the channel temperature sensors 3 are installed, and below the temperature plates 4, the channel temperature sensors 3 are fixed on the PCB board 6. The channel temperature sensors 3 are connected to the thermocouple acquisition system on the PCB board 6 through the printed circuit on the temperature plate 4. The thickness of the temperature plate 4 is customized, and is used to lift the respective channel temperature sensor 3 to the rear end of the conductive copper plate 103 of the respective thermocouple connector 1. The channel temperature sensor 3 and the conductive copper plate 103 are tightly combined through the heat-conducting silica gel sheet. In this embodiment, the channel temperature sensor 3 is raised in position through the double-layer PCB stacking mode, so as to achieve the purpose of tightly combining the channel temperature sensor 3 and the rear end of the conductive copper plate 103, reduce the distance of the heat conduction path, and improve the heat conduction rate.

[0026] In the problem of cold end temperature measurement, the premise of accurate measurement is to correctly measure the actual cold end of the thermocouple sensor. When the existing thermocouple connector measures the cold end temperature of the thermocouple sensor, it cannot measure the temperature of the actual cold end, but only measures the temperature near the pin of the thermocouple connector, and cannot quickly respond when the temperature fluctuates at the plug of the thermocouple sensor.

[0027] At the same time, after disassembling and measuring the existing thermocouple connector purchased on the market, it is found that the cross-sectional area of the copper sheet of the product is only 0.25mm*3.2mm, and the thickness of the heat-conducting material is relatively large, so the heat conduction rate is relatively low, which will cause the temperature data measured at the cold end to be delayed, and real-time cold end temperature measurement cannot be achieved. In order to improve this problem, the general thermocouple connector is abandoned, and self-design is carried out to reduce the problem of low heat conduction rate in cold end temperature measurement.

[0028] In this embodiment, the structure of the thermocouple connector is as shown in Figure 4 The thermocouple connector 1 is processed by 3D printing technology, and the reed 102 and the conductive copper plate 103 are processed by wire cutting. Figure 2 As shown in

[0029] As shown in Figure 1As shown, the cold end compensation structure of the thermocouple collection in the application is connected with the thermocouple sensor and the thermocouple collection system through the independently designed thermocouple connector 1, the thermocouple sensor plug is inserted into the thermocouple connector 1, and the isothermal block 2 is placed in the opening slot A of each thermocouple connector 1 and is tightly combined with the two conductive copper plates 103 of each thermocouple connector 1 through the heat-conducting silica gel sheet, so that the thermocouple connector 1 of each input channel is tightly combined through the heat-conducting silica gel sheet, so that the temperature inconsistency between the two electrodes of the thermocouple and the multiple thermocouples is avoided, and at the same time, the isothermal block 2 is also tightly combined with the internal temperature compensation circuit sensor 5 of the thermocouple collection system on the PCB 6 through the heat-conducting silica gel sheet, which ensures the real-time and accuracy of the cold end compensation, improves the overall heat capacity of the cold end structure, and reduces the temperature sensitivity of the cold end to the outside world. At the same time, the channel temperature sensor 3 is a temperature measuring device in the cold end compensation structure, and the rest is a service for temperature measurement, which is responsible for the conversion of the cold end temperature physical quantity and digital quantity; the temperature small plate 4 is a circuit board for installing the channel temperature sensor 3, and the thickness of the circuit small plate is a customized thickness, which realizes the lifting of the channel temperature sensor 3 to the rear end of the conductive copper plate 103 of the thermocouple connector 1, and ensures the accuracy of temperature measurement. In addition, the heat-conducting silica gel sheet is a buffer for the connection between each part, which not only ensures the high thermal conductivity, but also ensures the insulation.

[0030] In the embodiment, the isothermal block 2 is made of aluminum material with high thermal conductivity, which is tightly connected with the rear end of the conductive copper plate 103 of the thermocouple connector 1 through the heat-conducting silica gel sheet. The main functions of the isothermal block 2 are as follows:

[0031] 1. The isothermal block is made of aluminum material with high thermal conductivity, which can ensure the consistency of the overall temperature in the structure and can quickly change to improve the timeliness of the cold end temperature measurement;

[0032] 2. The isothermal block and the thermocouple connector are tightly connected through the heat-conducting silica gel sheet of high thermal conductivity material. Due to the existence of the isothermal block, the overall heat capacity of the cold end compensation structure is increased, which can improve the heat balance speed between the newly inserted thermocouple sensor plug and the cold end compensation structure, and improve the measurement speed;

[0033] 3. The isothermal block is tightly connected with the thermocouple connector through the heat-conducting silica gel sheet of high thermal conductivity material, which ensures the consistency of the positive and negative electrodes of the thermocouple connector and avoids the error caused by the inconsistency of the positive and negative electrodes of the cold end;

[0034] 4. The existence of the isothermal block and its high thermal conductivity improve the stability of the cold end compensation structure, reduce the temperature interference from the outside world to the minimum, and improve the robustness.

[0035] While the foregoing specific embodiments of the application have been described in some detail to provide a clear understanding thereof, it will be apparent to those of ordinary skill in the art that numerous modifications can be made to the specific embodiments described without departing from the spirit and scope of the application defined by the appended claims.

Claims

1. A cold junction acquisition compensation structure for thermocouples, characterized by, include: Four thermocouple connectors are provided, each connecting to one of the four thermocouple sensors. The four thermocouple sensors are connected to the thermocouple data acquisition system by inserting into their respective connectors. Each thermocouple connector consists of a housing, two spring plates, two conductive copper plates, and two conductive copper screws. The front end of the housing has two openings into which one of the spring plates is inserted. The rear end of the housing has two slots corresponding to the two openings. The two conductive copper plates are inserted along their respective slots from the rear end to the front end, pressing against the front spring plates. When the connector plugs are inserted, the two plugs of the thermocouple sensors are tightly abutted against the conductive copper plates by the corresponding spring plates. The slots are open on the upper side between the front and rear ends, exposing the upper sides of the slots on the two conductive copper plates. The rear ends of the two conductive copper plates are each screwed into screw holes on the PCB board by a conductive copper screw, which connect to the thermocouple data acquisition system. An internal temperature compensation circuit sensor for a thermocouple acquisition system is mounted on a PCB board. An isothermal block is placed in the opening slot of each thermocouple connector and is tightly bonded to the two conductive copper plates of each thermocouple connector through a thermally conductive silicone sheet. At the same time, the isothermal block is tightly bonded to the internal temperature compensation circuit sensor of the thermocouple acquisition system on the PCB board through a thermally conductive silicone sheet. The four-channel temperature sensors are temperature measuring devices in the cold junction compensation structure, and are respectively responsible for the conversion of the physical and digital quantities of the temperature of the two conductive copper plates of the four thermocouple connectors, i.e., the cold junction. Four small temperature boards, which are circuit boards for mounting channel temperature sensors, are located below the conductive copper plates at the rear of the four thermocouple connectors. Each of the aforementioned channel temperature sensors is mounted on top of the board and fixed to the PCB board below. The channel temperature sensors are connected to the thermocouple acquisition system on the PCB board through printed circuits on the temperature boards. The temperature boards have a custom thickness to raise each channel temperature sensor to be close to the rear of the conductive copper plate of its respective thermocouple connector. A thermally conductive silicone sheet is used to tightly bond the channel temperature sensor to the conductive copper plate.

2. The cold junction compensation structure for thermocouple pickup according to claim 1, wherein The isothermal block is made of aluminum, a material with high thermal conductivity.

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