CN105428153A - Semiconductor low-temperature thermal switch - Google Patents

Abstract

The invention discloses a semiconductor low-temperature thermal switch which utilizes a semiconductor refrigerating sheet to control the on and off of the heat transfer direction at low temperature, which comprises two heat sinks respectively connected with the cold source and the cooled object; A semiconductor cooler with good thermal contact with it. Based on the Peltier effect of the semiconductor, the invention realizes the "on" and "off" functions of the thermal switch by changing the current direction of the semiconductor refrigerating sheet. The low temperature thermal switch has the advantages of simple structure, convenient operation and timely response. When the heat switch is "on", the heat transfer efficiency is high, and the cooled object can obtain a lower temperature than the cold source; when the heat switch is "off", it can also act as a heating (rewarming) device.

Description

A semiconductor low temperature thermal switch

technical field

The invention relates to the field of low-temperature thermal switches, in particular to a semiconductor low-temperature thermal switch.

Background technique

In low temperature technology, it is often necessary to continuously control the temperature of the cooled object from low temperatures such as 4K, 20K or 77K to room temperature. To cool the object to be cooled to a low temperature, it is necessary to have a good thermal connection between the cold source and the object to be cooled, so as to realize the "on" state of the thermal switch. However, when the temperature of the cold object is to be raised, it is necessary to thermally isolate the cold source from the cold object, that is, to realize the "off" state of the thermal switch, which will not affect the temperature of the cold source, and can use less heating power Bring the cooled object to the desired temperature. When using liquid helium, liquid hydrogen or liquid nitrogen as a cold source, when the thermal switch is "off", the consumption of cryogenic liquid can be significantly reduced. If the cold source adopts the cold head of the cryogenic refrigerator, there is no need to adjust the temperature of the cold head or stop the machine for reheating, which reduces the operation and time consumption of the cryogenic refrigerator. As a thermal switch for low temperature applications it should have high reliability and short response time.

At present, the commonly used low temperature thermal switches mainly include mechanical type, gas gap type, superconducting type, shape memory alloy type, heat pipe type and other low temperature thermal switches. The mechanical thermal switch needs an external driving force, so the reliability is not high; the gas gap thermal switch needs to be inflated and pumped between two heat conducting plates, and the pumping time is directly related to the response time of the thermal switch. At the same time, the device It is complex; the cost of superconducting thermal switches is relatively high; the structure of shape memory alloy thermal switches requires strict symmetry and high processing precision; heat pipe thermal switches usually have a long response time.

Semiconductor refrigeration technology is based on the Peltier effect of semiconductors. When there is a DC current in a closed loop formed by two different metals, a temperature difference will occur between the two joints. The Peltier effect is reversible, and when the direction of the current is changed, the exothermic and endothermic joints also change. With the development of semiconductor technology, semiconductor refrigeration technology has matured day by day and has been applied in many fields.

SUMMARY OF THE INVENTION The object of the present invention is to provide a semiconductor low-temperature thermal switch, which realizes the on and off states of the thermal switch through the direction of the input current.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A semiconductor low-temperature thermal switch, characterized in that: it includes a semiconductor refrigeration sheet, and the surfaces on both sides of the semiconductor refrigeration sheet are respectively connected with heat sinks, wherein one side of the heat sink is used as a cold end heat sink to contact or connect with a cold source, and the other side of the heat sink As the hot-end heat sink is in contact with or connected to the object to be cooled, the semiconductor refrigerating sheet is also connected with a wire, and the wire is drawn from the side of the semiconductor refrigerating sheet not connected to the heat sink, and the state of opening and closing of the thermal channel is realized through the semiconductor refrigerating sheet.

The semiconductor low-temperature thermal switch described above is characterized in that: the heat sink on each side and the corresponding side surface of the semiconductor refrigeration sheet are fixedly connected by bolts with small thermal conductivity or heat bridges that have been specially treated, or other devices with small heat transfer can also be used. fixed connection.

The above-mentioned semiconductor low-temperature thermal switch is characterized in that: the surface of the semiconductor refrigeration sheet and the corresponding heat sink are respectively coated with low-temperature glue that is conducive to heat conduction, or pressed with an indium sheet, or pressed with a low-temperature heat conduction sealant. Excellent other materials.

The semiconductor low-temperature thermal switch is characterized in that: the semiconductor cooling chip can be a single-stage cooling chip, or a multi-stage semiconductor cooling chip or a plurality of single-stage cooling chips can be superimposed.

The above-mentioned semiconductor low-temperature thermal switch is characterized in that: the two heat sinks are made of metal or alloy material with good heat conduction at low temperature, preferably red copper material.

The above-mentioned semiconductor low-temperature thermal switch is characterized in that the two heat sinks can be made into corresponding matching shapes according to the shapes of the corresponding heat sinks and objects to be cooled.

The semiconductor low-temperature thermal switch is characterized in that the two heat sinks can be respectively connected with the cooling source and the object to be cooled as a whole.

The semiconductor low-temperature thermal switch is characterized in that: In addition to the position where the two heat sinks are in contact with the semiconductor refrigeration sheet, and the position used to connect with the cold source and the object to be cooled, heat insulating materials can also be added to other positions , or paste radiation-proof materials, or hollow out, so as to reduce heat transfer when the thermal switch is off.

The above-mentioned semiconductor low-temperature thermal switch is characterized in that: temperature measuring points can also be arranged on each side of the heat sink.

The working principle of the present invention is: when the low-temperature thermal switch is in the "on" state, the heat sink 2 at the hot end of the semiconductor refrigeration chip 3 is in contact with the cold source, and the heat sink 4 at the cold end is connected to the object to be cooled. A steady stream of energy reaches the object being cooled through the thermal switch. Due to the Peltier effect, the cooled object can obtain a lower temperature than that of the cold source, and the temperature of the cooled object can be adjusted by changing the voltage or current of the semiconductor refrigeration sheet. When the thermal switch needs to be turned off, it is only necessary to cut off the power supply, and when the temperature of the two heat sinks is the same, the current in the opposite direction is passed, and the cold and hot ends of the semiconductor refrigeration sheet are automatically exchanged. The heat sink 4 that links to each other at the semi-conductor refrigerating sheet then changes from the cold end to the hot end, and the temperature of the original cooled object under its heating will be higher than the temperature of the cold source, and the heat transfer channel from the cold source to the cooled object is cut off. The electric energy consumed by the semiconductor refrigeration sheet, together with the heat absorbed by the heat sink 2 from the cold source, is transferred from the cold source with a lower temperature to the cooled object with a higher temperature, so the semiconductor refrigeration sheet also acts as a heating (rewarming) device role.

The invention has the advantages of simple structure, safety and reliability, convenient operation, low cost, timely response and automatic control. When the heat switch is turned on, the heat transfer efficiency is high, and the cooled object can obtain a lower temperature than the cold source; when the heat switch is turned off, it can also act as a heating (rewarming) device.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention.

detailed description

Referring to Fig. 1, a semiconductor low-temperature thermal switch includes a semiconductor cooling chip 3, and the surfaces of both sides of the semiconductor cooling chip 3 are respectively connected with heat sinks 2 and 4, and one side of the heat sink 2 is used as a cold end heat sink in contact with a cold source Or connect, the other side heat sink 4 is contacted or connected with the cooled object as a heat end heat sink, and the semiconductor refrigeration sheet 3 is also connected with a wire 1, and the wire 1 is drawn from the side of the semiconductor refrigeration sheet 3 that is not connected to the heat sink, and passed through the semiconductor refrigeration sheet 3. The refrigerating sheet 3 realizes the opening and closing states of the hot channel.

The heat sinks 2 and 4 on each side are fixedly connected to the corresponding side surfaces of the semiconductor cooling fins 3 through bolts with small thermal conductivity or specially treated heat bridges, or other methods with small heat transfer can also be used for fixed connection.

The surface of the semiconductor cooling chip 3 and the corresponding heat sink are respectively coated with low-temperature glue which is conducive to heat conduction, or pressed with indium sheet, or pressed with other materials with excellent heat conduction at low temperature.

The semiconductor cooling chip 3 can be a single-stage cooling chip, and can also adopt a multi-stage semiconductor cooling chip or a stacked form of multiple single-stage cooling chips.

The two heat sinks 2 and 4 are made of metal or alloy material with good heat conduction at low temperature, preferably red copper material.

The two heat sinks 2, 4 can be made into corresponding matching shapes according to the shapes of the corresponding heat sinks and objects to be cooled.

The two heat sinks 2 and 4 can be respectively connected with the cooling source and the object to be cooled as a whole.

In addition to the position where the two heat sinks 2 and 4 are in contact with the semiconductor cooling plate 3, and the position used to connect with the cold source and the cooled object, other positions can also be added with heat insulating materials, or pasted with anti-radiation materials, or hollowed out. Heat transfer is thereby reduced in the off state of the thermal switch.

Temperature measuring points can also be arranged on each side of the heat sink.

The working method of the present invention is as follows: when the low-temperature thermal switch is in the "on" state, the heat sink 2 is in contact with the cold source, the heat sink 4 is connected with the cooled object, and the cooling capacity of the cold source passes through the thermal switch after the semiconductor refrigeration sheet 3 is powered Keep reaching the cold object. Due to the Peltier effect, the cooled object can obtain a lower temperature than the cold source, and the temperature obtained by the cooled object can be adjusted by changing the voltage or current of the semiconductor refrigeration sheet.

When the thermal switch needs to be turned off, it is only necessary to cut off the power supply, and when the temperature of the two heat sinks is the same, the current in the opposite direction is passed, and the cold and hot ends of the semiconductor refrigeration sheet are automatically exchanged. Under the heating of the heat sink 4 connected to the semiconductor refrigeration sheet, the temperature of the original "cooled object" will be higher than the temperature of the cold source, and the heat transfer channel from the cold source to the cooled object is cut off. The electric energy consumed by the semiconductor refrigerating sheet 3, together with the heat absorbed by the heat sink 2 from the cold source, is transferred from the cold source with a lower temperature to the "cooled object" with a higher temperature, so the semiconductor refrigerating sheet also acts as a heating (complex) temperature) function of the device.

Although the specific embodiments of the present invention have been described and illustrated in detail above through examples, it should be noted that those skilled in the art can make various changes and modifications to the above embodiments without departing from the principles of the present invention. The spirit and scope described in the claims.

Claims (9)

1. A semiconductor low-temperature thermal switch, characterized in that: it comprises a semiconductor refrigerating sheet, and the surfaces of both sides of the semiconductor refrigerating sheet are respectively connected with heat sinks, wherein one side of the heat sink contacts or connects with the cold source as a cold end heat sink, and the other side The heat sink is used as a hot end heat sink to contact or connect to the object to be cooled. The semiconductor cooling sheet is also connected to a wire, and the wire is drawn from the side of the semiconductor cooling sheet that is not connected to the heat sink. The opening and closing of the heat channel is realized through the semiconductor cooling sheet. state. 2. A semiconductor low-temperature thermal switch according to claim 1, characterized in that: the heat sink on each side and the corresponding side surface of the semiconductor refrigeration sheet are fixedly connected by bolts with small thermal conductivity or specially treated thermal bridges, or Use other methods with low heat transfer to fix the connection. 3. A semiconductor low-temperature thermal switch according to claim 1, characterized in that: the surface of the semiconductor cooling chip and the corresponding heat sink are respectively coated with low-temperature glue that is conducive to heat conduction, or an indium sheet is pressed, Or pressed with other materials that conduct heat well at low temperatures. 4. A semiconductor low-temperature thermal switch according to claim 1, characterized in that: the semiconductor cooling chip can be a single-stage cooling chip, or a multi-stage semiconductor cooling chip or a stack of multiple single-stage cooling chips can be used . 5. A semiconductor low-temperature thermal switch according to claim 1, characterized in that: the two heat sinks are made of metal or alloy materials that conduct heat well at low temperatures, preferably copper. 6. A semiconductor low-temperature thermal switch according to claim 1, characterized in that: the two heat sinks can be made into corresponding matching shapes according to the shapes of the corresponding heat sinks and objects to be cooled. 7. A semiconductor low-temperature thermal switch according to claim 1, characterized in that the two heat sinks can be respectively connected to the cooling source and the object to be cooled as a whole. 8. A semiconductor low-temperature thermal switch according to claim 1, characterized in that: except for the position in contact with the semiconductor refrigeration sheet and the position used to connect with the cold source and the cooled object on the two heat sinks, other positions It is also possible to add heat-insulating materials, or stick radiation-proof materials, or hollow out, so as to reduce heat transfer when the thermal switch is off. 9. A semiconductor low-temperature thermal switch according to claim 1, characterized in that: each side of the heat sink can also be equipped with temperature measurement points.