Vacuum chamber temperature measurement reference point device and vacuum chamber temperature measurement system

Abstract

The application discloses a kind of vacuum chamber temperature measurement reference point devices, including isothermal block of heat-conducting base and heat-conducting cover, heat-conducting base is equipped with several thermocouple fixed slots and thermal resistance perforation, heat-conducting cover is equipped with the protruding tooth matched with thermocouple fixed slot, the temperature measurement end head of reference thermocouple is arranged in thermocouple fixed slot, heat-conducting cover is covered on heat-conducting base, protruding tooth is embedded in thermocouple fixed slot and temperature measurement end head is pressed in the groove bottom of thermocouple fixed slot, thermal resistance perforation is located below thermocouple fixed slot, thermal resistance perforation is equipped with pressing plate, heat-conducting base is equipped with locking screw, thermal resistance is fixed between pressing plate and the hole wall of thermal resistance perforation by locking screw through pressing plate, isothermal block is provided with not less than two layers of heat shield layer.The application also discloses the vacuum chamber temperature measurement system using the reference point device.The application reduces the temperature deviation of reference thermocouple and thermal resistance and the overall temperature fluctuation is small.

Description

Technical Field

[0001] This invention relates to a temperature reference point device and a temperature measurement system, and particularly to a vacuum chamber temperature reference point device and a vacuum chamber temperature measurement system. Background Technology

[0002] For temperature measurement systems, thermocouple temperature measurement requires setting a temperature reference point for temperature compensation to obtain an accurate measured temperature. When using thermocouples for temperature measurement inside a vacuum chamber, setting the temperature reference point outside the vacuum chamber presents two problems. First, thermocouples consist of two different metal leads, such as a T-type thermocouple made of copper and constantan. The reference point outside the vacuum chamber needs to have the constantan wire led out through the chamber via a vacuum lead, which is typically made of copper, as constantan is difficult to achieve. Second, the temperature reference point requires a high-precision ice bath or constant temperature bath, resulting in a complex structure and high cost.

[0003] Chinese patent CN112345101A discloses a temperature measurement system that sets a temperature reference point in a vacuum chamber. The temperature reference point is a copper isothermal block encased in a thermal insulation component. The problems to be solved are how to minimize the temperature fluctuation of the isothermal block and how to ensure that the resistance temperature detector (RTD) can accurately measure the temperature of the thermocouple reference junction. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides a vacuum chamber temperature measurement reference point device, resolving the issues of temperature deviation and temperature fluctuation between the thermocouple reference terminal and the resistance temperature detector (RTD). This invention also provides a vacuum chamber temperature measurement system.

[0005] The technical solution of this invention is as follows: A vacuum chamber temperature measurement reference point device includes an isothermal block composed of a heat-conducting base and a heat-conducting cover. The heat-conducting base is provided with a plurality of thermocouple fixing slots and a thermocouple resistance through hole. The heat-conducting cover is provided with protruding teeth that match the thermocouple fixing slots. The temperature measuring end of the reference thermocouple is disposed in the thermocouple fixing slot. The heat-conducting cover is closed on the heat-conducting base. The protruding teeth are embedded in the thermocouple fixing slot and press the temperature measuring end against the bottom of the thermocouple fixing slot. The thermocouple resistance through hole is located below the thermocouple fixing slot. A pressure plate is provided in the thermocouple resistance through hole. The heat-conducting base is provided with a locking screw. The locking screw fixes the thermocouple between the pressure plate and the hole wall of the thermocouple resistance through hole through the pressure plate. At least two layers of thermal shielding layer are provided on the outside of the isothermal block.

[0006] Furthermore, the top surface of the heat-conducting base is provided with a cavity, the thermocouple fixing groove is disposed at the bottom of the cavity, and the heat-conducting cover is provided with a boss that is interference-fitted with the cavity. A protruding tooth is disposed on the platform of the boss, and the protruding tooth is interference-fitted with the thermocouple fixing groove. The interference fit between the heat-conducting cover and the heat-conducting base ensures close contact and uniform temperature, guaranteeing the overall temperature uniformity of the isothermal block and further reducing the temperature measurement deviation between the reference thermocouple and the resistance temperature detector.

[0007] Furthermore, the pressure plate and the hole wall of the thermal resistor are provided with opposing slots, and the slots are interference-fitted with the armored outer shell of the thermal resistor.

[0008] Furthermore, the heat-conducting base and the heat-conducting cover are made of copper.

[0009] Furthermore, since the reference thermocouple needs to be replaced and calibrated according to the different thermocouples used for temperature measurement, each of the thermal shielding layers includes a shielding can and a shielding cover that cooperate with each other for ease of operation. The shielding cans of multiple thermal shielding layers are stacked in sequence. The isothermal block is set in the innermost shielding can. A first thermal insulation pad is provided between the shielding cans and between the shielding can and the thermally conductive base. A second thermal insulation pad is provided between the shielding covers and between the shielding covers and the thermally conductive cover. A connecting post is fixed on the thermally conductive cover. The second thermal insulation pad and the shielding cover are alternately sleeved on the connecting post.

[0010] Furthermore, the shielding cover is provided with threading holes, and the threading holes of different thermal shielding layers are staggered. This can further reduce heat leakage caused by threading the reference thermocouple and thermistor.

[0011] A vacuum chamber temperature measurement system includes several thermocouples, a receiver, and a vacuum chamber temperature reference point device. The receiver is located outside the vacuum chamber, the thermocouples are located inside the heat sink of the vacuum chamber, and the vacuum chamber temperature reference point device is located between the heat sink and the cavity wall of the vacuum chamber. The common terminals of the thermocouples and the reference thermocouple are short-circuited inside the vacuum chamber. The temperature measuring wires of the thermocouples and the reference thermocouple, as well as the leads of the resistance temperature detector (RTD), extend from the vacuum chamber and connect to the receiver.

[0012] The advantages of the technical solution provided by this invention are as follows:

[0013] The isothermal block exhibits high temperature uniformity across its surface. Within the vacuum chamber heat sink at temperatures ranging from -183°C to 100°C, the temperature difference between the reference thermocouple and the resistance temperature detector (RTD) is less than 0.1°C, facilitating the replacement of the reference thermocouple. A multi-layered thermal shielding structure reduces heat leakage from the isothermal block to the vacuum environment, ensuring temperature stability. Insulating pads separate the thermal shielding layers, and staggered wiring holes further reduce heat leakage, ensuring that the isothermal block temperature variation does not exceed 0.05°C within a single temperature measurement cycle, thus improving the accuracy of the temperature measurement system. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the vacuum chamber temperature measurement system as an example.

[0015] Figure 2 This is a schematic diagram of the vacuum chamber temperature measurement reference point device in an embodiment. Detailed Implementation

[0016] The present invention will be further described below with reference to embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. After reading this description, any modifications of this description in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0017] Please combine Figure 1As shown, the vacuum chamber temperature measurement system of this embodiment includes a vacuum chamber 1, a heat sink 2 inside the vacuum chamber 1, and a shield 3 outside the heat sink 2. The temperature inside the vacuum chamber 1 is controlled by the heat sink 2, and the controlled temperature is -183~100℃. The object to be measured is placed inside the heat sink 2. Temperature measuring thermocouples 4 are attached to the surface of the object to be measured. In this embodiment, these temperature measuring thermocouples 4 are T-type copper-constantan thermocouples. The thermocouple temperature compensation methods include fixed reference point method, internal reference point method of the data acquisition unit (dynamic temperature) and external temperature compensation method of the data acquisition unit (dynamic temperature). If the reference point is placed outside the vacuum chamber 1, the constantan wire end a needs to be led to the outside of the vacuum chamber 1 through the vacuum chamber lead wire. Generally, the vacuum chamber lead wire is made of copper, and constantan is difficult to achieve. If a fixed reference point is used outside the vacuum chamber, a high-precision ice bath or constant temperature bath needs to be configured, which is complex in structure and expensive. Therefore, in this embodiment, a vacuum chamber temperature measuring reference point device 5 is also set in the vacuum chamber, located between the shield 3 and the cavity wall of the vacuum chamber 1. The vacuum chamber temperature measurement reference point device 5 is equipped with a reference thermocouple 6 and a resistance temperature detector (RTD) 7. The reference thermocouple 6 is a T-type copper-constantan thermocouple, and the RTD 7 is a PT100. The constantan lead b of the reference thermocouple 6 and the constantan lead of the temperature-measuring thermocouple 4 are both connected to the constantan shorting point 8 inside the vacuum chamber. The copper leads of the reference thermocouple 6, the temperature-measuring thermocouple 4, and the PT100 RTD 7 are then connected to the vacuum chamber penetration connector 9, leading out to the outside of the vacuum chamber, and further connected to the receiving end 10 outside the vacuum chamber 1 for temperature measurement. The specific structure of the receiving end 10 is existing technology and will not be described in detail.

[0018] The structure of the vacuum chamber temperature measurement reference point device 5 used in this embodiment is as follows: Figure 2 As shown, it includes an isothermal block and three thermal shielding layers 501 disposed outside the isothermal block. The isothermal block mainly consists of two parts, namely a heat-conducting base 502 and a heat-conducting cover 503. Both the heat-conducting base 502 and the heat-conducting cover 503 are made of copper. The two are fitted together to form a cuboid shape. Of course, the specific shape is not necessarily like this, but the cuboid structure is easy to process.

[0019] A recessed cavity 504 is formed downwards on the top surface of the heat-conducting base 502. Several thermocouple mounting slots 505 are formed downwards from the bottom of the cavity 504. These thermocouple mounting slots 505 are used to mount reference thermocouples 6. The depth of the thermocouple mounting slots 505 is preferably centered on the entire structure after the heat-conducting cover 503 is closed on the top surface of the heat-conducting base 502. A transverse through-hole 506 for mounting a resistance temperature detector (RTD) 7 is formed below the thermocouple mounting slots 505, penetrating the heat-conducting base 502. A U-shaped pressure plate 507 is provided inside the RTD 506, with its opening facing upwards. A slot is formed on the top wall of the RTD 506, opposite to the opening of the U-shaped pressure plate 507. The opening of the U-shaped pressure plate 507 also forms a slot for clamping the armored outer shell of the RTD 7. The specific installation method involves inserting a locking screw 508 into the bottom surface of the heat-conducting base 502, and then using the locking screw 508 to push the U-shaped pressure plate 507 upwards. This ensures that the armored outer shell of the thermal resistor 7, the opening of the U-shaped pressure plate 507, and the slot on the top wall of the thermal resistor through hole 506 all form an interference fit, allowing the thermal resistor 7 to be in close contact with the heat-conducting base 502 and have sufficient contact area to ensure the accuracy of temperature measurement.

[0020] Opposite to the cavity 504 of the heat-conducting base 502, a boss 509 is machined on the bottom surface of the heat-conducting cover 503 to interfere with the cavity 504, and a tooth 510 is machined on the platform of the boss 509 to interfere with the thermocouple fixing groove 505. After the reference thermocouple 6 is placed in the thermocouple fixing groove 505, the heat-conducting cover 503 is fixedly closed to the heat-conducting base 502 by screws 511. The tooth 510 presses the temperature measuring end of the reference thermocouple 6 against the bottom of the thermocouple fixing groove 505, and the temperature measuring end of the reference thermocouple 6 is in close contact with the heat-conducting cover 503 and the heat-conducting base 502.

[0021] The function of the heat shielding layer 501 is to delay the influence of the temperature inside the vacuum chamber 1 on the temperature of the heat-conducting base 502 and the heat-conducting cover 503 as much as possible, so as to stabilize the temperature of the isothermal block, reduce temperature fluctuations during the sampling period, and improve the temperature measurement accuracy. The specific structure of the heat shielding layer 501 is as follows: the heat shielding layer 501 consists of a shielding can 5011 and a shielding cover 5012. A first heat-insulating pad 512 is placed between the bottom surface of the first layer shielding can 5011 and the bottom surface of the heat-conducting base 502. A stepped heat-insulating sleeve is inserted into the bottom surface of the second layer shielding can 5011. A section of the first heat-insulating pad 512 is exposed on the upper and lower sides of the bottom surface of the second layer shielding can 5011, forming the bottom surface of the second layer shielding can 5011 and the bottom surface of the first layer shielding can 5011 and the bottom surface of the third layer shielding can 5011, respectively. A fastening bolt 513 is inserted through the heat-insulating sleeve and through the first heat-insulating pad 512 between the bottom surface of the first-layer shielding can 5011 and the bottom surface of the heat-conducting base 502, connecting the first-layer shielding can 5011 and the second-layer shielding can 5011 to the heat-conducting base 503. These three layers of shielding cans 5011 are stacked sequentially, with the isothermal block placed inside the innermost shielding can 5011. A threaded connecting post 514 is screwed into the center of the heat-conducting cover 503. A second heat-insulating pad 515, a first-layer shielding cover 5012, a second heat-insulating pad 515, a second-layer shielding cover 5012, a second heat-insulating pad 515, a second-layer shielding cover 5012, a second heat-insulating pad 515, and a third-layer shielding cover 5012 are then sequentially fitted onto the threaded connecting post 514 and secured with a nut 516. Each of the three shielding covers 5012 has a wire hole 5012a. The wire holes 5012a of the different shielding covers 5012 are arranged alternately. The leads of the reference thermocouple 6 and the resistance temperature detector 7 pass through the wire hole 5012a and finally connect to the vacuum chamber connector 9.

Claims

1. A vacuum chamber temperature measurement reference point device, characterized in that, An isothermal block comprising a heat-conducting base and a heat-conducting cover. The heat-conducting base has several thermocouple mounting slots and RTD (thermal resistance temperature detector) through-holes. The heat-conducting cover has protruding teeth that match the thermocouple mounting slots. The temperature-sensing tip of a reference thermocouple is positioned within the thermocouple mounting slot. The heat-conducting cover is fitted onto the heat-conducting base. The protruding teeth are embedded in the thermocouple mounting slots and press the temperature-sensing tip against the bottom of the slots. The RTD through-holes are located below the thermocouple mounting slots and contain a pressure plate. The heat-conducting base is equipped with locking screws. The locking screw fixes the thermal resistor between the pressure plate and the wall of the through hole of the thermal resistor through the pressure plate. The isothermal block is provided with no less than two layers of thermal shielding layer. The top surface of the thermally conductive base is provided with a cavity. The thermocouple fixing groove is provided at the bottom of the cavity. The thermally conductive cover is provided with a boss that is interference fit with the cavity. The protruding teeth are provided on the platform of the boss. The protruding teeth are interference fit with the thermocouple fixing groove. The pressure plate and the wall of the through hole of the thermal resistor are provided with opposing slots. The slots are interference fit with the armored outer shell of the thermal resistor. The heat-conducting base and the heat-conducting cover are made of copper. Each of the heat shielding layers includes a shielding can and a shielding cover that cooperate with each other. The shielding cans of multiple heat shielding layers are stacked in sequence. The isothermal block is set in the innermost shielding can. A first heat insulation pad is provided between the shielding cans and between the shielding can and the heat-conducting base. A second heat insulation pad is provided between the shielding covers and between the shielding covers and the heat-conducting cover. A connecting post is fixed on the heat-conducting cover. The second heat insulation pad and the shielding cover are alternately sleeved on the connecting post. The shielding cover is provided with wire holes, and the wire holes of different heat shielding layers are arranged alternately.

2. A vacuum chamber temperature measurement system, characterized in that, The device includes several temperature-measuring thermocouples, a receiving end, and a vacuum chamber temperature measurement reference point device as described in claim 1. The receiving end is disposed outside the vacuum chamber, the temperature-measuring thermocouples are disposed inside the heat sink of the vacuum chamber, the vacuum chamber temperature measurement reference point device is disposed between the heat sink and the cavity wall of the vacuum chamber, the common terminals of the temperature-measuring thermocouples and the reference thermocouples are short-circuited inside the vacuum chamber, and the temperature-measuring wires of the temperature-measuring thermocouples and the reference thermocouples, as well as the leads of the resistance temperature detector (RTD), extend out from the vacuum chamber and connect to the receiving end.

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