CN215450002U

CN215450002U - Thermostat device capable of carrying out continuous variable temperature control of wide temperature zone

Info

Publication number: CN215450002U
Application number: CN202121924733.6U
Authority: CN
Inventors: 李海波; 李艳锋; 蔡旭东; 代永光
Original assignee: Csic Pride Nanjing Cryogenic Technology Co ltd
Current assignee: China Shipbuilding Pengli Nanjing Ultra Low Temperature Technology Co ltd
Priority date: 2021-08-16
Filing date: 2021-08-16
Publication date: 2022-01-07
Anticipated expiration: 2031-08-16

Abstract

The utility model discloses a thermostat device capable of carrying out continuous variable temperature control in a wide temperature area, which comprises a low-temperature refrigeration system, a sample cavity assembly, a heat insulation assembly and a sample temperature control system, wherein a sample rod body (43) in the sample cavity assembly is provided with a sample temperature sensor (54) and a sample heater (55) which are respectively connected with a temperature controller (57) in the sample temperature control system, the temperature controller (57) is connected with an upper computer (56) through a circuit, and the upper computer (56) carries out PID closed-loop control on the sample temperature sensor (54) and the sample heater (55) through the temperature controller (57); and a static helium pressure sensor (64) connected with the upper computer (56) is arranged on a static helium pipeline communicated with a static helium interface (47) in the sample cavity assembly. The device can be used for continuous variable temperature control in a wide temperature range of 2-800K, and meets the requirements of the current high-end physical property measurement field.

Description

Thermostat device capable of carrying out continuous variable temperature control of wide temperature zone

Technical Field

The utility model belongs to the research field of low-temperature instruments and devices, low-temperature control methods and physical property measurement technologies, and particularly relates to a thermostat device which is based on a small low-temperature refrigerator and can perform continuous variable temperature control in a wide temperature range by throttling and cooling liquid helium.

Background

Cryostats with temperature scanning functionality are commonly used in the field of physical property measurements. With the continuous development of material technology, more and more new materials are developed successfully, and the development of physical property measurement for verifying the properties of the materials is a very necessary link. However, these materials have a wide range of applications, and a wide range of physical properties under the application of a magnetic field or a radiation field is often required, which puts higher demands on a physical property measuring apparatus. For thermostats for physical property measurements, there is a need for wider temperature zones, more continuous temperature changes, more open structures (to apply a specific physical field), more precise temperature control.

At present, the research on the low-temperature thermostat in China has a great gap with Europe, America and Japan, and especially, a thermostat with a wide temperature range below 4K for measuring physical properties still leaves a great gap. At present, the domestic published patents such as CN105355319A, CN205246278U, CN207456918U and liquid nitrogen cryostat are that the lowest temperature is in a liquid nitrogen temperature region of about 77K, and the structural design without an external physical field can not meet the requirement of the existing high-end physical property measurement. For example, CN108800638A, CN107655236A ultra-low vibration cryostat, can reach 4K liquid helium temperature zone, but has a large difference from the international leading refrigeration temperature; and the device does not have the capability of operating in a high-temperature region because of no overheat protection capability.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problems of narrow temperature zone range, high temperature zone lower limit, discontinuous temperature change and the like of the conventional cryostat, and provides a thermostat device which is based on a small-sized cryogenic refrigerator and can perform continuous temperature change control of a wide temperature zone by utilizing liquid helium throttling cooling.

The utility model aims to solve the problems by the following technical scheme:

a thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone is characterized in that: the device comprises a low-temperature refrigeration system, a sample cavity assembly, a heat insulation assembly and a sample temperature control system, wherein a sample rod body for placing a sample in the sample cavity assembly is provided with a sample temperature sensor and a sample heater, the sample temperature sensor and the sample heater are respectively connected with a temperature controller in the sample temperature control system, the temperature controller is connected with an upper computer through a circuit, and the upper computer performs PID closed-loop control on the sample temperature sensor and the sample heater through the temperature controller; and a static helium pressure sensor for monitoring the static helium pressure is arranged on a static helium pipeline communicated with a static helium interface for controlling the static helium pressure in the sample cavity assembly, and the static helium pressure sensor is connected with an upper computer to feed back the pressure of the static helium.

The low-temperature valve in the low-temperature refrigeration system is provided with a low-temperature valve adjusting and controlling mechanism in communication connection with an upper computer, the upper computer sets the stroke of a low-temperature valve needle of the low-temperature valve through the low-temperature valve adjusting and controlling mechanism, and the low-temperature valve adjusting and controlling mechanism can feed back the stroke of the low-temperature valve needle to the upper computer.

The liquid helium pipeline in the low-temperature refrigeration system is provided with a liquid helium temperature sensor and a liquid helium heater which can be controlled in a linkage mode, the liquid helium temperature sensor and the liquid helium heater are respectively connected with a temperature controller, and an upper computer performs PID closed-loop control on the liquid helium temperature sensor and the liquid helium heater through the temperature controller.

A flow meter for monitoring the flow rate of the circulating helium and a circulating helium pressure sensor for monitoring the pressure of the circulating helium are arranged on a circulating helium pipeline in the low-temperature refrigeration system, and the flow meter and the circulating helium pressure sensor are respectively connected with an upper computer to feed back the flow rate and the pressure of the circulating helium; the flow meter is positioned at the rear side of an air outlet of a circulating pump on the circulating helium pipeline; and the circulating helium pressure sensor is positioned on the front side of an air inlet of a circulating pump on the circulating helium pipeline.

Temperature monitoring points are respectively arranged on the primary heat radiation screen and the secondary heat radiation screen in the heat insulation and heat insulation assembly, and temperature sensors arranged at the temperature monitoring points are respectively connected with a temperature controller so as to feed back the temperature monitored in real time to an upper computer; a vacuum cavity in the heat insulation assembly is provided with a vacuum pump, and the vacuum pump is connected with an upper computer, so that the upper computer can control the vacuum degree in the vacuum cavity through the vacuum pump.

The local downward projection of the heat insulation and heat insulation assembly forms a heat insulation and heat insulation sinking cavity to accommodate a sample cavity bottom barrel in the sample cavity assembly, and a sample rod body in the sample cavity assembly extends into the sample cavity bottom barrel.

The heat insulation assembly comprises a vacuum cavity, a primary heat radiation screen and a secondary heat radiation screen, wherein the vacuum cavity is formed by combining a vacuum cavity flange and a vacuum cavity cylinder, and the bottom of the vacuum cavity cylinder partially protrudes downwards; the vacuum cavity comprises a vacuum cavity body, a first-level heat radiation screen flange, a first-level heat radiation screen lower extension part, a second-level heat radiation screen lower extension part and a second-level heat radiation screen lower extension part, wherein the first-level heat radiation screen is formed by combining a first-level heat radiation screen cylinder body and a first-level heat radiation screen flange and is suspended in the vacuum cavity body; the second-level heat radiation screen formed by combining the second-level heat radiation screen cylinder body and the second-level heat radiation screen flange is suspended in the first-level heat radiation screen.

The low-temperature refrigeration system comprises a refrigerator, a refrigerator cavity, a low-temperature valve controlled by a low-temperature valve adjusting and controlling mechanism and a helium circulating system, wherein a cold head of the refrigerator is inserted into the refrigerator cavity, the refrigerator and the refrigerator cavity are in thermal coupling by adopting compression joint, and an elastic heat conduction module is arranged at a secondary cold head of the refrigerator and is in thermal coupling with a refrigerator cavity bottom flange of the refrigerator cavity; a refrigerator cavity liquid helium outlet at the bottom of the refrigerator cavity is communicated with a low-temperature valve liquid helium inlet on a low-temperature valve seat of a low-temperature valve in the second-stage heat radiation screen through a liquid helium pipeline in the second-stage heat radiation screen in the heat insulation and heat insulation assembly, a low-temperature valve liquid helium outlet on the low-temperature valve seat is communicated with a sample cavity liquid helium inlet at the bottom of a sample cavity interlayer in the sample cavity assembly through a pipeline, a circulating helium outlet at the top of the sample cavity interlayer is connected with a circulating helium inlet on a refrigerator cavity through a circulating helium pipeline with a circulating pump, and a helium circulating system is formed by the refrigerator cavity, a liquid helium pipeline between the refrigerator cavity liquid helium outlet and the low-temperature valve liquid helium inlet, an inner cavity flow channel of the low-temperature valve seat, a pipeline between the low-temperature valve liquid helium outlet and the sample cavity liquid helium inlet, a sample cavity interlayer in the sample cavity assembly, and a circulating helium pipeline between the circulating helium outlet and the circulating helium inlet.

The elastic heat conduction module is composed of a heat conduction module top plate, a flexible heat conduction chain, a spring and a heat conduction module bottom plate, the heat conduction module top plate is in direct contact with a secondary cold head of the refrigerator, the heat conduction module bottom plate is in direct contact with a refrigerator cavity bottom flange, and the heat conduction module bottom plate is supported by the spring and is in thermal coupling with the heat conduction module top plate through the flexible heat conduction chain.

The sample cavity assembly comprises a sample cavity outer cylinder, a sample cavity inner cylinder, a sample cavity bottom cylinder serving as an extension section of the sample cavity inner cylinder, a sample cavity flange, a sample rod and a sample rod flange, wherein a sample rod body of the sample rod is inserted into the sample cavity inner cylinder and the sample cavity bottom cylinder, and the sample rod is fixed on the sample cavity flange through the sample rod flange; the rod body heat radiation screens are uniformly distributed on the rod body of the sample rod; and a low-temperature helium flow after the low-temperature valve flows through the sample cavity interlayer to cool a helium cavity formed by the sample cavity inner cylinder and the sample cavity bottom cylinder, and enters a circulating helium pipeline from a circulating helium outlet at the upper end of the sample cavity interlayer.

Compared with the prior art, the utility model has the following advantages:

the liquid helium throttling and cooling part in the device adopts the self-designed low-temperature valve to replace the traditional capillary device, and the flow resistance of the throttling valve is changed, so that the temperature of the throttled helium and the liquid helium proportion can be regulated and controlled, and the helium flow can be finely adjusted, therefore, the regulation and redistribution of the cooling capacity can be realized without greatly changing the temperature of the refrigerator; the device can provide a low-temperature environment of a sample 2K by combining a 4K GM refrigerator and a JT valve, and has a lower low-temperature region compared with a thermostat adopting a single refrigerator.

The sample cavity assembly is provided with a sample cavity interlayer, dynamic low-temperature helium flows through the sample cavity interlayer and conducts heat with a sample through static helium in a helium cavity, so that the heat conduction between a cooling source and the sample can be controlled by adjusting the pressure of the static helium in the helium cavity; when the device is operated in a low-temperature area, the static helium pressure can be increased to enhance heat exchange; when the high-temperature area operates, the static helium pressure is reduced as much as possible to weaken heat exchange; in addition, the circulating helium in the interlayer of the sample cavity can be used for cooling the wall surfaces of the outer cylinder and the inner cylinder of the sample cavity, so that the temperature protection effect is achieved, and the damage to equipment caused by overheating of the wall surface of the sample cavity is prevented; therefore, compared with other thermostat equipment, the device has a higher high-temperature area; i.e. the device has the advantage of a wider temperature range.

The device adopts the sectional temperature control of the low-temperature and high-temperature areas, the low-temperature area and the high-temperature area are divided into a plurality of small temperature areas, each small temperature area is set with different PID closed-loop control parameters to control the heater, the overall control of software is matched, the smooth transition among the temperature areas is realized, and finally the continuous temperature change of the device is realized, and the sample temperature change rate is adjustable.

The sample temperature control system in the device has an emergency processing function, other temperature monitoring points in the thermostat device except the sample position exceed the normal temperature to a certain degree, the upper computer can give an alarm, the power supply of the sample heater is cut off, and the device is prevented from being damaged.

The device adopts a more open structure, and the sample cavity bottom cylinder and the matched structure thereof extend downwards relative to the main body part, so that external influences such as a magnetic field, neutron beams and the like can be conveniently exerted on the position of a sample, and the requirements of various physical property measurement environments are met.

The refrigerator in the device of the utility model is in thermal coupling with the refrigerator cavity by adopting compression joint, and the elastic heat conducting module is arranged at the secondary cold head of the refrigerator and is in good thermal coupling with the refrigerator cavity.

The lower section of the primary heat radiation screen in the device provided by the utility model wraps the bottom cylinder of the sample cavity, so that the influence of heat radiation on the device in a high-temperature state of the sample is avoided.

The device provided by the utility model adopts liquid helium throttling to provide a low-temperature environment, and is matched with air pressure control and sample heating control in a sample cavity to realize low-temperature-high-temperature zone sectional control of the sample temperature, smooth transition is controlled among sections, and the change rate of the sample temperature is adjustable, so that the device can realize continuous temperature change control in a wide temperature zone of 2-800K, the requirements of the current high-end physical property measurement field are met, and the blank of the domestic technology is filled.

Drawings

FIG. 1 is a schematic structural diagram of a thermostat device capable of performing continuous variable temperature control in a wide temperature range according to the present invention;

FIG. 2 is a schematic structural diagram of an elastic heat conducting module according to the present invention;

FIG. 3 is a control schematic of the sample temperature control system of the present invention.

Wherein: 1-a refrigerator; 2-refrigerator mounting flange; 3-the upper section of the refrigerator cavity; 4, transferring the refrigerator cavity; 5-the lower section of the refrigerator cavity; 6-refrigerator cavity bottom flange; 7-refrigerator cavity; 8, an elastic heat conducting module; 9-a heat conducting module top plate; 10-flexible heat-conducting chains; 11-a spring; 12-a heat conducting module base plate; 13-vacuum chamber flange; 14-vacuum chamber cylinder; 15-primary thermal radiation screen flange; 16-a primary heat radiation screen cylinder; 17-a secondary thermal radiation screen flange; 18-a secondary thermal radiation screen cylinder; 19-liquid helium outlet of refrigerator cavity; 20-liquid helium line; 21-low temperature valve liquid helium inlet; 22-low temperature valve liquid helium outlet; 23 — sample chamber liquid helium inlet; 24-a low temperature valve; 25-low temperature valve regulating mechanism; 26-low temperature valve bellows; 27-low temperature valve normal temperature flange; 28-low temperature valve stem; 29-outer wall of low temperature valve; 30-a low temperature valve guide block; 31-low temperature valve primary heat sink; 32-low temperature valve secondary heat sink; 33-low temperature valve needle; 34-a cryovalve seat; 35-sample cavity outer cylinder; 36-sample cavity inner barrel; 37-sample chamber flange; 38-sample chamber primary heat sink; 39-lower extension of first-level heat radiation screen; 40-sample chamber bottom cylinder; 41-sample rod; 42-sample rod flange; 43-sample rod body; 44-rod thermal radiation screen; 45-helium gas chamber; 46-circulating helium outlet; 47-static helium interface; 48-circulating pump; 49-circulation loop charging valve; 50-circulation loop inflation interface; 51-static helium charge valve; 52-static helium gas charging interface; 53-circulating helium gas inlet; 54-sample temperature sensor; 55-sample heater; 56-an upper computer; 57-temperature control instrument; 58-a flow meter; 59-circulating helium pressure sensor; 60-a vacuum pump; 61-liquid helium temperature sensor; 62-liquid helium heater; 63-a circulating helium line; 64-static helium pressure sensor.

Detailed Description

The utility model is described in detail below with reference to the drawings and specific examples. It is to be understood that the described embodiments are merely exemplary of the utility model, and not restrictive of the full scope of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1-3: the utility model provides a thermostat device capable of carrying out continuous variable temperature control in a wide temperature zone.

As shown in fig. 1 and fig. 2, the low-temperature refrigeration system mainly includes a refrigerator 1, a refrigerator cavity 7, an elastic heat conduction module 8, a liquid helium pipeline 20, a low-temperature valve 24, a low-temperature valve adjusting mechanism 25, a circulating pump 48, a circulating loop charging valve 49, and a circulating helium pipeline 63. The refrigerator is characterized in that a cold head of a refrigerator 1 is inserted into a refrigerator cavity 7, the refrigerator 1 and the refrigerator cavity 7 are in thermal coupling by adopting compression joint, the refrigerator 1 is installed on a vacuum cavity flange 13 through a refrigerator installation flange 2, the refrigerator cavity 7 comprises a refrigerator cavity upper section 3 and a refrigerator cavity lower section 5, a primary cold head of the refrigerator 1 is positioned in the refrigerator cavity upper section 3, a secondary cold head of the refrigerator 1 is positioned in the refrigerator cavity lower section 5, the primary cold head of the refrigerator 1 and a primary heat radiation screen flange 15 are in thermal coupling through a refrigerator cavity adapter 4, and temperature synchronization is achieved; the secondary cold head of the refrigerator 1 is thermally coupled with the secondary heat radiation screen flange 17 through the refrigerator cavity bottom flange 6, so as to achieve temperature synchronization. An elastic heat conduction module 8 is arranged at the secondary cold head of the refrigerator 1 and is thermally coupled with a refrigerator cavity bottom flange 6 of a refrigerator cavity 7; a refrigerator cavity liquid helium outlet 19 at the bottom of the refrigerator cavity 7 is communicated with a low-temperature valve liquid helium inlet 21 on a low-temperature valve seat 34 of a low-temperature valve 24 in the secondary heat radiation screen through a liquid helium pipeline 20 in the secondary heat radiation screen in the heat insulation and heat insulation assembly, a low-temperature valve liquid helium outlet 22 on the low-temperature valve seat 34 is communicated with a sample cavity liquid helium inlet 23 at the bottom of a sample cavity interlayer in the sample cavity assembly through a pipeline, and a circulating helium outlet 46 at the top of the sample cavity interlayer is connected with a circulating helium inlet 53 on the refrigerator cavity 7 through a circulating helium pipeline 63 with a circulating pump 48.

The helium circulating system is composed of the refrigerator cavity 7, the liquid helium pipeline 20 between the refrigerator cavity liquid helium outlet 19 and the low-temperature valve liquid helium inlet 21, the inner cavity flow channel of the low-temperature valve seat 34, the pipeline between the low-temperature valve liquid helium outlet 22 and the sample cavity liquid helium inlet 23, the sample cavity interlayer in the sample cavity assembly, and the circulating helium pipeline 63 between the circulating helium outlet 46 and the circulating helium inlet 53. The flow control of the circulating helium is realized by adjusting the flow of the circulating pump 48 through the upper computer 56, an air inlet branch of a circulating helium pipeline 63 where the circulating pump 48 is located is connected with the helium storage tank, and a circulating loop inflation valve 49 is arranged on the air inlet branch and is connected with the helium storage tank through a circulating loop inflation interface 50. Because the liquid helium temperature sensor 61 and the liquid helium heater 62 which can be controlled in a linkage manner are arranged on the liquid helium pipeline 20, the liquid helium temperature sensor 61 and the liquid helium heater 62 are respectively connected with the temperature controller 57, and the upper computer 56 performs PID closed-loop control on the liquid helium temperature sensor 61 and the liquid helium heater 62 through the temperature controller 57 to accurately control the temperature; namely, the temperature control of the circulating helium gas is realized by adjusting the power of the liquid helium heater 62 behind the secondary cold head of the refrigerator 1.

As shown in fig. 2, the elastic heat conducting module 8 is composed of a heat conducting module top plate 9, a flexible heat conducting chain 10, a spring 11, and a heat conducting module bottom plate 12, the heat conducting module top plate 9 is in direct contact with the secondary cold head of the refrigerator 1, the heat conducting module bottom plate 12 is in direct contact with the refrigerator cavity bottom flange 6, and the heat conducting module bottom plate 12 is supported by the spring 11 and is thermally coupled with the heat conducting module top plate 9 through the flexible heat conducting chain 10.

As shown in fig. 1, the low temperature valve 24 is composed of a low temperature valve adjusting mechanism 25, a low temperature valve bellows 26, a low temperature valve normal temperature flange 27, a low temperature valve stem 28, a low temperature valve outer wall 29, a low temperature valve guide block 30, a low temperature valve needle 33, a low temperature valve seat 34 and other parts; the low temperature valve 24 is in thermal coupling with the primary heat radiation screen flange 15 through the low temperature valve primary heat sink 31 in sequence, and is in thermal coupling with the secondary heat radiation screen flange 17 through the low temperature valve secondary heat sink 32. The opening degree adjustment of the low-temperature valve 24 by the low-temperature valve adjusting and controlling mechanism 25 is mainly to adjust a fit clearance between the low-temperature valve needle 33 and the low-temperature valve seat 34, and because the low-temperature valve adjusting and controlling mechanism 25 is in communication connection with the upper computer 56, the upper computer 56 sets the stroke of the low-temperature valve needle 33 of the low-temperature valve 24 through the low-temperature valve adjusting and controlling mechanism 25, and the low-temperature valve adjusting and controlling mechanism 25 can feed back the stroke of the low-temperature valve needle 33 to the upper computer 56. When the opening degree of the low-temperature valve 24 is increased, the low-temperature valve needle 33 moves upwards, so that the needle hole matching of the low-temperature valve needle 33 and the low-temperature valve seat 34 becomes loose and the gap is increased; when the opening degree of the low temperature valve 24 is reduced, the low temperature valve needle 33 moves downward, so that the low temperature valve needle 33 is tightly fitted with the needle hole of the low temperature valve seat 34, and the gap is reduced. The size of the gap is in positive correlation with the size of the flow resistance of the low-temperature valve 24, and the flow resistance of the low-temperature valve 24 can be adjusted by adjusting the valve needle 33 of the low-temperature valve, so that the flow regulation function of liquid helium/gaseous helium is realized. For example: under the low-temperature environment, the opening degree of the low-temperature valve 24 is properly adjusted to reduce the gap, increase the flow resistance and reduce the temperature of the throttled liquid helium.

It should be noted that the cryogenic valve 24 can be replaced by a plurality of circuits with adjustable flow resistance.

When the low-temperature refrigeration system operates, helium with micro-positive pressure enters the refrigerator cavity 7 from the circulating helium inlet 53, is sequentially contacted with the primary cold head and the secondary cold head of the refrigerator 1 for heat exchange and is liquefied, and liquid helium enters the low-temperature valve liquid helium inlet 21 from the liquid helium outlet 19 of the refrigerator cavity through the liquid helium pipeline 20; liquid helium is decompressed and expanded through the low-temperature valve 24 to become a gas-liquid mixed helium flow with lower temperature, then flows out of the low-temperature valve 24, enters a sample cavity interlayer between the sample cavity outer cylinder 35 and the sample cavity inner cylinder 36 from the sample cavity liquid helium inlet 23, exchanges heat with the sample cavity from bottom to top, the helium after temperature rise is pumped out by a circulating pump 48 from a circulating helium outlet 46 at the upper end of the sample cavity interlayer, whether pressurization is carried out or not is determined according to actual conditions, and the helium is conveyed to a circulating helium inlet 53 on the refrigerator cavity 7 again through a circulating helium pipeline 63, so that a refrigeration cycle is completed. In addition, when the device runs for a long time, the liquid helium is increased and the helium pressure is reduced, at the moment, the circulation loop inflation valve 49 is opened, and the circulation loop is supplemented with helium from the circulation loop inflation interface 50, so that the normal running of the low-temperature refrigeration system is maintained.

In addition, a flow meter 58 for monitoring the flow rate of the circulating helium and a circulating helium pressure sensor 59 for monitoring the pressure of the circulating helium are arranged on the circulating helium pipeline 63, and the flow meter 58 and the circulating helium pressure sensor 59 are respectively connected with the upper computer 56 to feed back the flow rate and the pressure of the circulating helium; the flow meter 58 is positioned on the rear side of the air outlet of the circulation pump 48 on the circulation helium pipe 63, and the circulation helium pressure sensor 59 is positioned on the front side of the air inlet of the circulation pump 48 on the circulation helium pipe 63.

As shown in fig. 1, the heat insulation assembly comprises a vacuum cavity, a primary heat radiation screen and a secondary heat radiation screen, wherein the vacuum cavity is formed by combining a vacuum cavity flange 13 and a vacuum cavity cylinder 14, and the bottom of the vacuum cavity cylinder 14 partially protrudes downwards; the primary heat radiation screen formed by combining the primary heat radiation screen cylinder 16 and the primary heat radiation screen flange 15 is suspended in the vacuum cavity, a primary heat radiation screen lower extension section 39 which penetrates through the bottom of the primary heat radiation screen cylinder 16 from the primary heat radiation screen flange 15 downwards and extends to the lower convex part of the vacuum cavity cylinder 14 is arranged on the primary heat radiation screen, and the part of the primary heat radiation screen lower extension section 39 extending out of the bottom of the vacuum cavity cylinder 14 and the lower convex part of the vacuum cavity cylinder 14 form a heat insulation and heat insulation lower sinking cavity; the second-level heat radiation screen formed by combining the second-level heat radiation screen cylinder 18 and the second-level heat radiation screen flange 17 is suspended in the first-level heat radiation screen. The vacuum cavity formed after the vacuum cavity flange 13 is connected with the vacuum cavity barrel 14 is vacuumized through the vacuum pump 60, and heat leakage caused by gas heat conduction between the interior of the device and the external environment is reduced. The heat radiation screen cylinder body and the flange thereof are both made of high heat conduction materials and are subjected to surface emissivity reduction treatment, so that the radiation heat leakage process is interrupted, and the radiation heat leakage of the system is greatly reduced; the lower section 39 of the primary heat radiation screen wraps the bottom barrel 40 of the sample cavity to avoid the influence of heat radiation of the sample in a high-temperature state on the device body.

On the basis, temperature monitoring points are respectively arranged on the primary heat radiation screen and the secondary heat radiation screen, and temperature sensors arranged at the temperature monitoring points are respectively connected with a temperature controller 57 so as to feed back the temperature monitored in real time to the upper computer 56; because the vacuum pump 60 of the vacuum cavity configuration is connected with the upper computer 56, the upper computer 56 can control the vacuum degree in the vacuum cavity through the vacuum pump 60.

The sample cavity component comprises a sample rod 41, a sample rod flange 42, a sample cavity flange 37, a sample cavity outer cylinder 35, a sample cavity inner cylinder 36, a sample rod body 43, a rod body heat radiation screen 44, a helium cavity 45 and a sample cavity bottom cylinder 40 from top to bottom. The sample cavity assembly is thermally coupled to the primary heat radiation screen flange 15 through a sample cavity primary heat sink 38; the sample rod body 43 of the sample rod 41 is inserted into the sample cavity inner barrel 36 and the sample cavity bottom barrel 40, and the sample rod 41 is fixed on the sample cavity flange 37 through the sample rod flange 42; a plurality of heat radiation screens 44 arranged in parallel are arranged on the sample rod body 43, so that the radiation heat leakage at the sample position can be effectively reduced; because the sample chamber bottom barrel 40 and its associated structure project downwardly relative to the main body portion, it facilitates the application of external influences, such as magnetic fields, neutron beams, etc., at the sample site. A sample cavity interlayer is arranged between the sample cavity outer cylinder 36 and the sample cavity inner cylinder 35, and two ends of the sample cavity interlayer are respectively communicated with the sample cavity liquid helium inlet 23 and the circulating helium outlet 46; the low-temperature helium gas after the low-temperature valve 24 flows through the sample cavity interlayer and cools the sample cavity inner barrel 36, the sample is cooled through the heat exchange between the static helium gas filled in the helium gas cavity 45 and the sample cavity inner barrel 36 due to the fact that the sample is mainly conducted through the static helium gas, and the helium gas after the heat exchange enters the circulating helium gas pipeline 63 from the circulating helium gas outlet 46 at the upper end of the sample cavity interlayer.

In addition, because the sample temperature sensor 54 and the sample heater 55 are arranged on the sample rod body 43 for placing the sample, the sample temperature sensor 54 and the sample heater 55 are respectively connected with the temperature controller 57 in the sample temperature control system, the temperature controller 57 is connected with the upper computer 56 through a circuit, and the upper computer 56 performs PID closed-loop control on the sample temperature sensor 54 and the sample heater 55 through the temperature controller 57. Meanwhile, a static helium pressure sensor 64 for monitoring the static helium pressure is arranged on a static helium pipeline which is positioned at the top end of the sample cavity inner barrel 36 and is communicated with a static helium interface 47 for controlling the static helium pressure, and the static helium pressure sensor 64 is connected with the upper computer 56 to feed back the pressure of the static helium; when the pressure of the static helium gas in the static helium gas pipeline needs to be regulated, the pressure of the static helium gas in the helium gas cavity 45 can be regulated through the static helium gas charging valve 51 and the static helium gas charging interface 52, so that the heat exchange amount between the sample and the outside is regulated.

The sample temperature control system provided by the utility model can be used for carrying out low-temperature-high-temperature zone sectional type temperature control. Wherein 2-300K is a low-temperature region, 300-800K is a high-temperature region, and the two temperature regions adopt different temperature control modes. The temperature control system is composed of an upper computer 56, a temperature controller 57, a low-temperature valve regulating mechanism 25, a flow meter 58, a circulating helium pressure sensor 59, a vacuum pump 60, a static helium pressure sensor 64 and a circulating pump 48, wherein the temperature controller 57 respectively adopts a PID closed-loop control sample temperature sensor 54 and a sample heater 55, a liquid helium temperature sensor 61 and a liquid helium heater 62. The upper computer 56 performs overview control, and sets a target value according to the feedback data; manipulated variables for the sample temperature control system include the opening of the cryovalve 24, the flow and temperature of the circulating helium gas, the circulating helium and static helium pressures, and the power of the sample heater 55 on the sample rod body 43. The low-temperature-high-temperature area is divided into a plurality of small temperature areas, different control parameters are set in each small temperature area, the smooth transition among the temperature areas is realized by matching with the overall control of an upper computer, and finally the continuous temperature change of the device is realized and the sample temperature change rate is adjustable.

When the device is used for controlling a low-temperature zone of 2-300K, firstly, the air pressure in a helium cavity 45 for storing a sample is controlled at 200-500Pa by a static helium inflation valve 51 on a static helium pipeline and a static helium inflation interface 52 communicated with the static helium pipeline, so that the static helium has good heat conductivity; secondly, the opening degree of the low-temperature valve 24 is reduced by controlling the low-temperature valve adjusting and controlling mechanism 25, so that the liquid helium in the liquid helium pipeline 20 can be fully throttled and cooled; the throttled low-temperature circulating helium cools the inner cylinder 36 of the sample cavity, and the sample is cooled through static helium heat conduction; the sample position is provided with a sample temperature sensor 54 and a sample heater 55, the PID closed loop control is adopted, and when the sample temperature is lower than a set value, the sample heater 55 can heat the sample until the temperature reaches the set value.

When the device of the utility model is used for controlling the high-temperature zone of 300-800K, the sample is heated by the PID controlled sample heater 55 to reach the set high-temperature zone temperature. To prevent the main body of the device from being damaged by the high temperature of the sample, it is necessary to insulate the high temperature sample and cool the sample chamber. Firstly, controlling the air pressure in a helium cavity 45 for storing a sample to be below 1Pa through a static helium inflation valve 51 on a static helium pipeline and a static helium inflation interface 52 communicated with the static helium pipeline, wherein the static helium is in a molecular flow state at the moment, so that the heat quantity which can be transferred and guided out by the static helium for the high-temperature sample is extremely small, and the total heat leakage quantity of the high-temperature sample is lower than 15W through simulation calculation and basically coincides with the actual test; and secondly, the opening degree of the low-temperature valve 24 is increased by controlling the low-temperature valve adjusting mechanism 25, the helium flow resistance is reduced, and the helium flow can effectively cool the wall of the sample cavity only by about 2 liters per minute. The system controls the temperature of the wall surface of the sample chamber to be lower than the room temperature by adjusting the temperature and the flow of the circulating helium, the flow control of the circulating helium is realized by adjusting the flow of a circulating pump 48, and if the helium is insufficient, the air is supplied through an air charging interface 50 of a circulating loop; the temperature control of the circulating helium gas is realized by adjusting the power of the liquid helium heater 62 behind the secondary cold head of the refrigerator 1, and the liquid helium heater 62 and the liquid helium temperature sensor 61 adopt PID closed-loop control to accurately control the temperature.

It should be noted that, when the temperature is at the node of 300K, the apparatus of the present invention may select either the low temperature zone control method or the high temperature zone control method.

When the sample temperature control system of the utility model is used for controlling the low-temperature zone, the pressure of the static helium in the sample cavity is controlled within the range of 200-500Pa, the opening degree of the low-temperature valve 24 is smaller, the circulating helium is liquefied by the refrigerating machine 1, the liquid helium is throttled to obtain lower temperature, and the static helium in the sample cavity is taken as a heat-conducting medium to cool the sample, and the process is matched with the sample heater 55 controlled by the PID closed loop to work jointly, so that the accurate temperature control of the sample is finally realized. When the sample temperature control system controls a high-temperature region, the pressure of static helium in the sample cavity is controlled to be below 1Pa, the opening degree of the low-temperature valve 24 is large, the static helium in the sample cavity is in a molecular flow state, and the heat transfer between the sample cavity and a sample is extremely small; the sample is heated by a sample heater 55, and the sample heater 55 adopts PID closed-loop control to realize accurate temperature control; in order to prevent the wall surface of the sample cavity from overheating and damaging the device, the system controls the temperature of the wall surface of the sample cavity by regulating the temperature and the flow of the circulating helium gas exchanging heat with the sample cavity. The sample temperature control system has an emergency processing function, and immediately cuts off the output of the sample heater 55 when the temperature fed back by the temperature controller 57 exceeds a safe region; that is, except for the sample position, once the rest temperature monitoring points of the device exceed the normal temperature to a certain extent, the sample temperature control system can alarm to cut off the power supply of the sample heater 55, thereby avoiding the damage of the device.

Specifically, when the device of the utility model is used for controlling a high-temperature area, the flow control of the circulating helium is realized by adjusting the flow of the circulating pump 48, and an air inlet branch of a circulating helium pipeline 63 where the circulating pump 48 is arranged is connected with a helium storage tank; the temperature control of the circulating helium gas is realized by adjusting the power of the liquid helium heater 62 behind the secondary cold head of the refrigerator 1, and the liquid helium heater 62 and the liquid helium temperature sensor 61 adopt PID closed-loop control to accurately control the temperature.

The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby, and any modification made on the basis of the technical scheme according to the technical idea proposed by the present invention falls within the protection scope of the present invention; the technology not related to the utility model can be realized by the prior art.

Claims

1. A thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone is characterized in that: the device comprises a low-temperature refrigeration system, a sample cavity assembly, a heat insulation assembly and a sample temperature control system, wherein a sample temperature sensor (54) and a sample heater (55) are arranged on a sample rod body (43) for placing a sample in the sample cavity assembly, the sample temperature sensor (54) and the sample heater (55) are respectively connected with a temperature controller (57) in the sample temperature control system, the temperature controller (57) is connected with an upper computer (56) through a circuit, and the upper computer (56) performs PID closed-loop control on the sample temperature sensor (54) and the sample heater (55) through the temperature controller (57); and a static helium pressure sensor (64) for monitoring the static helium pressure is arranged on a static helium pipeline communicated with a static helium interface (47) for controlling the static helium pressure in the sample cavity assembly, and the static helium pressure sensor (64) is connected with the upper computer (56) to feed back the pressure of the static helium.

2. The thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone according to claim 1, characterized in that: low temperature valve (24) among the low temperature refrigeration system go up to dispose low temperature valve regulating and controlling mechanism (25) with host computer (56) communication connection, host computer (56) set for the stroke of low temperature valve needle (33) of low temperature valve (24) through low temperature valve regulating and controlling mechanism (25), and low temperature valve regulating and controlling mechanism (25) can feed back the stroke of low temperature valve needle (33) to host computer (56).

3. The thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone according to claim 1, characterized in that: a liquid helium temperature sensor (61) and a liquid helium heater (62) which can be controlled in a linkage mode are arranged on a liquid helium pipeline (20) in the low-temperature refrigeration system, the liquid helium temperature sensor (61) and the liquid helium heater (62) are respectively connected with a temperature controller (57), and an upper computer (56) carries out PID closed-loop control on the liquid helium temperature sensor (61) and the liquid helium heater (62) through the temperature controller (57).

4. The thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone according to claim 1, characterized in that: a flow meter (58) for monitoring the flow rate of the circulating helium and a circulating helium pressure sensor (59) for monitoring the pressure of the circulating helium are arranged on a circulating helium pipeline (63) in the low-temperature refrigeration system, and the flow meter (58) and the circulating helium pressure sensor (59) are respectively connected with an upper computer (56) to feed back the flow rate and the pressure of the circulating helium; the flow meter (58) is positioned at the rear side of the air outlet of the circulating pump (48) on the circulating helium pipeline (63); and the circulating helium pressure sensor (59) is positioned on the front side of the air inlet of the circulating pump (48) on the circulating helium pipeline (63).

5. The thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone according to claim 1, characterized in that: temperature monitoring points are respectively arranged on the primary heat radiation screen and the secondary heat radiation screen in the heat insulation and heat insulation assembly, and temperature sensors arranged at the temperature monitoring points are respectively connected with a temperature controller (57) so as to feed back the temperature monitored in real time to an upper computer (56); a vacuum cavity in the heat insulation assembly is provided with a vacuum pump (60), and the vacuum pump (60) is connected with an upper computer (56) so that the upper computer (56) can control the vacuum degree in the vacuum cavity through the vacuum pump (60).

6. The thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone according to claim 1, characterized in that: the local downward projection of the heat insulation and heat insulation assembly forms a heat insulation and heat insulation sinking cavity to accommodate a sample cavity bottom barrel (40) in the sample cavity assembly, and a sample rod body (43) in the sample cavity assembly extends into the sample cavity bottom barrel (40).

7. The thermostat device capable of carrying out wide-temperature-zone continuous temperature change control according to any one of claims 1 to 6, characterized in that: the heat insulation assembly comprises a vacuum cavity, a primary heat radiation screen and a secondary heat radiation screen, wherein the vacuum cavity is formed by combining a vacuum cavity flange (13) and a vacuum cavity cylinder (14), and the bottom of the vacuum cavity cylinder (14) partially protrudes downwards; the vacuum heat insulation sinking cavity is characterized in that a primary heat radiation screen formed by combining a primary heat radiation screen cylinder (16) and a primary heat radiation screen flange (15) is suspended in the vacuum cavity, a primary heat radiation screen lower extension section (39) which penetrates through the bottom of the primary heat radiation screen cylinder (16) from the primary heat radiation screen flange (15) downwards and extends to the lower convex part of the vacuum cavity cylinder (14) is arranged on the primary heat radiation screen, and the part of the primary heat radiation screen lower extension section (39) extending out of the bottom of the vacuum cavity cylinder (14) and the lower convex part of the vacuum cavity cylinder (14) form a heat insulation sinking cavity; the secondary heat radiation screen formed by combining a secondary heat radiation screen cylinder (18) and a secondary heat radiation screen flange (17) is suspended in the primary heat radiation screen.

8. The thermostat device capable of carrying out wide-temperature-zone continuous temperature change control according to any one of claims 1 to 6, characterized in that: the low-temperature refrigeration system comprises a refrigerator (1), a refrigerator cavity (7), a low-temperature valve (24) controlled by a low-temperature valve adjusting and controlling mechanism (25) and a helium circulating system, wherein a cold head of the refrigerator (1) is inserted into the refrigerator cavity (7), the refrigerator (1) and the refrigerator cavity (7) are in thermal coupling by adopting compression joint, and an elastic heat conduction module (8) is arranged at the position of a secondary cold head of the refrigerator (1) and is in thermal coupling with a refrigerator cavity bottom flange (6) of the refrigerator cavity (7); a refrigerator cavity liquid helium outlet (19) at the bottom of the refrigerator cavity (7) is communicated with a low-temperature valve liquid helium inlet (21) on a low-temperature valve seat (34) of a low-temperature valve (24) in the second-stage heat radiation screen through a liquid helium pipeline (20) in the second-stage heat radiation screen in the heat insulation and heat insulation assembly, a low-temperature valve liquid helium outlet (22) on the low-temperature valve seat (34) is communicated with a sample cavity liquid helium inlet (23) at the bottom of a sample cavity interlayer in the sample cavity assembly through a pipeline, a circulating helium outlet (46) at the top of the sample cavity interlayer is connected with a circulating helium inlet (53) on the refrigerator cavity (7) through a circulating helium pipeline (63) with a circulating pump (48), the refrigerator cavity (7), the liquid helium pipeline (20) between the refrigerator cavity liquid helium outlet (19) and the low-temperature valve liquid helium inlet (21), and an inner cavity flow channel of the low-temperature valve seat (34), And a helium circulating system is formed by a pipeline between the low-temperature valve liquid helium outlet (22) and the sample cavity liquid helium inlet (23), a sample cavity interlayer in the sample cavity assembly, and a circulating helium pipeline (63) between the circulating helium outlet (46) and the circulating helium inlet (53).

9. The thermostat device capable of carrying out continuous variable temperature control of a wide temperature zone according to claim 8, characterized in that: elasticity heat conduction module (8) constitute by heat conduction module roof (9), flexible heat conduction chain (10), spring (11), heat conduction module bottom plate (12), heat conduction module roof (9) and the second grade cold head direct contact of refrigerator (1), heat conduction module bottom plate (12) and refrigerator cavity bottom flange (6) direct contact, support through spring (11) between heat conduction module bottom plate (12) and heat conduction module roof (9), and through flexibility heat conduction chain (10) thermal coupling.

10. The thermostat device capable of carrying out wide-temperature-zone continuous temperature change control according to any one of claims 1 to 6, characterized in that: the sample cavity assembly comprises a sample cavity outer cylinder (35), a sample cavity inner cylinder (36), a sample cavity bottom cylinder (40) serving as an extension section of the sample cavity inner cylinder (36), a sample cavity flange (37), a sample rod (41) and a sample rod flange (42), wherein a sample rod body (43) of the sample rod (41) is inserted into the sample cavity inner cylinder (36) and the sample cavity bottom cylinder (40), and the sample rod (41) is fixed on the sample cavity flange (37) through the sample rod flange (42); the rod body (43) of the sample rod is uniformly provided with rod body heat radiation screens (44); and a sample cavity interlayer is formed between the sample cavity outer cylinder (35) and the sample cavity inner cylinder (36), a low-temperature helium flow behind the low-temperature valve (24) flows through the sample cavity interlayer to cool a helium cavity (45) formed by the sample cavity inner cylinder (36) and the sample cavity bottom cylinder (40), and enters a circulating helium pipeline (63) from a circulating helium outlet (46) at the upper end of the sample cavity interlayer.