CN114894825A - Frozen soil CT scanning device and method for precise temperature control - Google Patents
Frozen soil CT scanning device and method for precise temperature control Download PDFInfo
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Abstract
The invention discloses a frozen soil CT scanning device and a method for precise temperature control, which are applied to the technical field of mechanics experiments, and the device comprises a main body, a scanning bin, a cooling fin, an objective table, a ray source, a detector, an internal temperature measurer, a thermal imager, an inlet pipe, a pressure valve, a flow control pressure reducer, an inlet temperature measurer, a first electronic switch, a second electronic switch, an outlet pipe, an outlet temperature measurer, a third electronic switch, a fourth electronic switch and a cold bath system, wherein a cold source is provided for an inner cavity through the inlet pipe and the outlet pipe, cold energy is introduced into a frozen soil sample in the scanning bin for precooling, and then the cold source is provided for the scanning bin through a pipeline, so that the cold source is circularly frozen to the frozen soil sample, the whole environment where the frozen soil sample is located is cooled, the refrigeration efficiency is improved, and the temperature is uniformly cooled; the scanning method can be suitable for CT nondestructive scanning of low-temperature frozen soil samples under various conditions, and interference on frozen soil is reduced to the maximum extent by adopting two cooperative refrigeration modes of pre-cooling and final cooling.
Description
Technical Field
The invention relates to the technical field of mechanics experiments, in particular to a frozen soil CT scanning device and method for accurate temperature control.
Background
Frozen earth is a relatively complex comprehensive geologic body and generates sensitive response along with the thermal disturbance of the external environment. As the foundation of the engineering structure, the influence of thermal disturbance inevitably causes the change of engineering stability. The natural environment of the alpine and high-altitude areas is severe, large continuous and discontinuous permafrost is distributed, great challenges are brought to the construction and safe operation of highways, and the development of highways in western regions is severely restricted by the problem of the frozen soil. The macroscopic mechanical response of the frozen soil is usually interconnected with the microscopic scales such as matrix cracks, pores and the like, and the formation, the expansion, the breakage and the interaction of the microscopic cracks are the main reasons for forming the macroscopic cracks, so that the microscopic damage evolution mechanism of the frozen soil is explored by applying a detection means, the macroscopic scale and engineering scale analysis is facilitated, and important basic data is provided for exploring the damage mechanism of the frozen soil roadbed diseases. CT is used as a nondestructive detection technology to be widely used for identifying the microscopic damage characteristics and the expansion process of a soil body, and is characterized in that the layer surface of a detected object is scanned by an X-ray beam, the X-ray penetrating through the layer surface is received by a detector, converted into visible light, converted into an electric signal by photoelectric conversion, converted into a digital signal by an analog/digital converter and input into a computer for processing and analysis.
The research on the mesoscopic basic theory of the frozen soil is developed, and the research on the mesoscopic damage evolution behavior is very important to provide a specific low-temperature environment. The first problem is that: in the existing frozen soil CT scanning, most tests are performed by applying CT fast scanning after a sample is frozen in a low-temperature environment box, and the CT scanning result is roughly considered to be a CT scanning result at a certain freezing temperature, but in the scanning process, the frozen soil sample is subjected to heat exchange, part of microscopic structures are changed, and the influence on an original sample is larger. The second problem is that: the traditional CT scanning collaborative cooling mode is realized by adopting a constant-temperature water bath, the CT scanning is carried out by penetrating through an object and analyzing through density identification, and the constant-temperature water bath inevitably produces effect influence on visual scanning. The third problem is that: the temperature control accuracy in low temperature environments is inaccurate. The frozen soil is a four-phase body consisting of soil particles, air, water and ice, the microscopic structure of the frozen soil can be greatly influenced by weak change of temperature, meanwhile, the environment of the frozen soil in the nature is extremely complex, the temperature is 0-80 ℃, and accurate temperature control of equipment is a precondition for carrying out frozen soil scanning. The fourth problem is that: partial equipment capable of realizing low-temperature CT scanning still has a local cooling phenomenon, and the local cooling phenomenon still can influence the microscopic structure of the frozen soil, because when the frozen soil has a temperature gradient, water in the soil is transferred from a high potential energy position to a low potential energy position, and the moisture migration phenomenon is easy to occur, so that the frozen soil with the initially uniformly distributed moisture content forms a freezing edge, a freezing front surface and an ice lens body, and the phenomenon can cause the occurrence of errors in mechanism analysis and research.
Disclosure of Invention
The invention aims to overcome the defects that the microscopic structure of the frozen soil sample is changed during freezing and the CT scanning result is influenced in the prior art, and provides a frozen soil CT scanning device and method for precise temperature control.
In order to achieve the above purpose, the invention provides the following technical scheme:
the utility model provides a frozen soil CT scanning device for accurate accuse temperature, its device includes the ray source, the detector, main part and scanning storehouse, the main part is established between ray source and detector, main part and scanning storehouse can be penetrated through by the ray, be equipped with the cavity in the main part, the scanning storehouse is established in the cavity, be used for placing the frozen soil sample in the scanning storehouse, be the inner chamber between scanning storehouse outer wall and the main part inner wall, scanning storehouse and inner chamber are connected with the pipeline that is used for the cold source circulation respectively, still be equipped with the temperature measuring device who is used for surveying the temperature in the scanning storehouse.
Through establishing the scanning storehouse in the main part, at inside inner chamber and the scanning storehouse of forming of main part, provide the cold source for the inner chamber through the pipeline, can make the frozen soil sample in the scanning storehouse evenly carry out the precooling, the rethread pipeline provides the scanning storehouse with the cold source, and then carry out the circulating refrigeration of cold source to the frozen soil sample, two kinds of collaborative refrigeration modes of precooling and final cooling are provided, make the whole environment that the frozen soil sample is located cool down, the at utmost has reduced the interference to the frozen soil, frozen soil sample and external heat exchange take place when can avoiding the experiment, eliminate the moisture migration phenomenon of frozen soil sample, avoid frozen soil sample inner structure to change, eliminate the influence to the CT scanning, can obtain more real scanning result, provide the basis for the judgement of frozen soil mesoscopic damage action.
In a preferred embodiment of the present invention, the pipeline for circulating the cold source includes an inlet pipe and an outlet pipe, one end of the inlet pipe and one end of the outlet pipe are respectively connected to the cold bath system, the other end of the inlet pipe and the other end of the outlet pipe are respectively connected to the main body and extend into the scanning bin, the inlet pipe is provided with an inlet for providing the cold source in the inner cavity and the scanning bin, the outlet pipe is provided with an outlet for returning the cold source in the inner cavity and the scanning bin, the inlet pipe is located above the outlet pipe, and the cold source outlet of the inlet pipe in the scanning bin is opened upward; through the design of import pipe and outlet pipe, can provide the cold source for inner chamber and scanning storehouse respectively, through the cold source export setting of import pipe, avoid the cold source to blow frozen soil sample directly, through the upper and lower setting of import pipe and outlet pipe for air conditioning from the top down motion, steam from the bottom up moves, forms effectual cold source circulation in scanning the storehouse.
In a preferred embodiment of the present invention, the main body is provided with a thermal insulation material layer or made of a thermal insulation material, the scanning chamber is provided with a thermal conduction material layer or made of a thermal conduction material; through the setting of heat-insulating material, can reduce or avoid the dissipation of cold volume, provide stable precooling temperature in the inner chamber, through the setting of heat-conducting material, can make in the quick leading-in scanning storehouse of cold volume in the inner chamber, realize the short time and to the whole cooling in the scanning storehouse, effectively avoided frozen soil sample to produce the moisture migration, reduce the microscopic analysis influence to the later stage.
In a preferred embodiment of the present invention, the inlet pipe is provided with a pressure valve and a flow control pressure reducer; through pressure valve and flow control pressure reducer, can adjust the cold volume that the import pipe provided, ensure pressure and flow stability, guarantee that cold volume is in suitable scope, realize the accurate control of cold volume and temperature.
In a preferred embodiment of the present invention, the inner wall of the scanning chamber is further provided with cooling fins extending over the inner wall; the cooling capacity transferred by the inner cavity can be rapidly guided into the scanning bin through the cooling fins, and the maximum cooling efficiency is realized.
In a preferred embodiment of the present invention, the temperature measuring device includes an internal temperature measuring device and a thermal imaging device; through inside thermometer and thermal imager, can measure the inside temperature in scanning storehouse, in time feed back the flow control pressure reducer with the temperature in the storehouse of will scanning in order to carry out the synchronization adjustment, can control in real time.
In a preferred embodiment of the present invention, the inlet tube is provided with a first electronic switch at a cold source inlet of the inner cavity, and the inlet tube is provided with a second electronic switch at a cold source outlet of the scanning bin; the outlet pipe is provided with a third electronic switch at the cold source inlet of the inner cavity, and is provided with a fourth electronic switch at the cold source outlet of the scanning bin; through the setting of four electronic switches, can carry out on-off control to the import pipe cold source export in inner chamber and the scanning storehouse and the backward flow cold source export of outlet pipe respectively, realize that the interior intracavity cold source of inner chamber provides and the interior cold source of scanning storehouse provides independent the going on.
In a preferred embodiment of the present invention, the inlet pipe outside the main body is provided with an inlet thermometer, and the outlet pipe outside the main body is provided with an outlet thermometer; the cold source temperature of the inlet pipe can be monitored in real time through the inlet temperature measuring meter, and the cold source temperature of the outlet pipe can be monitored in real time through the outlet temperature measuring meter, so that the cold quantity is ensured to be maintained in a constant range.
In a preferred embodiment of the present invention, two inlet pipes and two outlet pipes are respectively adopted, one inlet pipe and one outlet pipe are respectively connected to the inner cavity, and the other inlet pipe and the other outlet pipe are respectively connected to the scanning chamber; the inlet pipe and the outlet pipe which are connected with the inner cavity and the scanning bin are respectively arranged, so that a cold source channel provided for the inner cavity and a cold source channel provided for the scanning bin can be separated and independently arranged, and different cold source selections are provided.
A frozen soil CT scanning method for accurate temperature control adopts the frozen soil CT scanning device for accurate temperature control, an objective table for placing frozen soil samples is arranged in a scanning bin, and the scanning method comprises the following steps:
s1, placing the frozen soil sample in an initial state on an objective table, adjusting the position of a main body between a ray source and a detector, adjusting a scanning bin to be centered in the main body, and connecting an inlet pipe and an outlet pipe with a cold bath system respectively to finish the installation of the device;
s2, turning on a first electronic switch and a third electronic switch, turning off a second electronic switch and a fourth electronic switch, then turning on a cold bath system, adjusting output cold through a pressure valve, adjusting a flow control pressure reducer through an inlet temperature detector, ensuring that the cold is in a preset temperature range, enabling the cold to enter an inner cavity through a pipeline to start circulation, integrally cooling a scanning cabin, and pre-cooling a frozen soil sample;
s3, uniformly reducing the temperature in the scanning bin to the experimental temperature through precooling, enabling the moisture in the frozen soil sample to be in phase change, enabling the frozen soil sample not to be subjected to moisture migration, then turning on the second electronic switch and the fourth electronic switch, and enabling the cold source to enter the scanning bin through a pipeline;
s4, adjusting the cold quantity and the flow rate through the flow control pressure reducer, ensuring that the temperature of the internal temperature detector reaches a target value, the difference value between the inlet temperature detector and the outlet temperature detector is smaller than a required value, and simultaneously, the internal temperature of the frozen soil sample displayed by the thermal imaging instrument is uniform, thereby completing the freezing process of the frozen soil sample;
and S5, starting CT scanning after the temperature displayed by the internal thermometer does not fluctuate to obtain a full-section three-dimensional image of the frozen soil sample, closing the cold bath system after scanning is finished, closing the flow control pressure reducer, the first electronic switch, the second electronic switch, the third electronic switch and the fourth electronic switch after the pressure valve is reduced to zero, and taking out the frozen soil sample.
Through installing the device, ensure that the scanning storehouse is located between ray source and the detector, through carrying out the precooling to the frozen soil sample, carry out whole cooling to the scanning storehouse, can transmit cold volume to the frozen soil sample uniformly, avoid the local difference in temperature to lead to the moisture migration in the frozen soil sample, through carrying out the final cooling to the scanning storehouse, accomplish the final cooling to the frozen soil sample, realize freezing, carry out thermostatic control through flow control pressure reducer, keep the invariant of temperature, ensure that the temperature in the scanning storehouse maintains at predetermined scope, accomplish and freeze, this method can be through two kinds of refrigeration methods in coordination of precooling and final cooling, the at utmost reduces the influence of freezing process to the experiment.
Compared with the prior art, the invention has the beneficial effects that:
1. the device can provide a double-layer structure of an inner cavity and a scanning bin, a cold source is provided for the inner cavity through a pipeline for precooling, and then is provided for the scanning bin through the pipeline for further freezing, so that the cold source can be respectively provided and transmitted to a frozen soil sample, and the whole environment where the frozen soil sample is located is uniformly cooled; the cold quantity and the temperature are maintained through the pressure valve and the flow control pressure reducer, and the accurate control of the temperature is realized; through the arrangement of the main body and the scanning bin material, heat exchange between the frozen soil sample and the outside during an experiment can be avoided, and the refrigeration efficiency can be improved to the maximum extent; the device has reasonable structural design, complete functions and convenient operation, and meets the technical requirements of the field of frozen soil scientific research.
2. The method can be suitable for CT nondestructive scanning of low-temperature frozen soil samples under various conditions, adopts two cooperative refrigeration modes of pre-cooling and final cooling, reduces interference on the frozen soil to the greatest extent, eliminates the moisture migration phenomenon of the frozen soil samples, avoids the change of the internal structure of the frozen soil samples, eliminates the influence on CT scanning, can obtain more real scanning results, and provides a basis for judging microscopic damage behaviors of the frozen soil.
Drawings
FIG. 1 is a schematic diagram of a CT scanning device for precisely controlling temperature of frozen earth according to the present invention;
FIG. 2 is a step diagram of a CT scanning method of frozen soil for precise temperature control according to the present invention.
The labels in the figure are: 1-a cold bath system; 2-a pressure valve; 3-flow control pressure reducer; 4-a radiation source; 5-inlet thermometer; 6-a electronic switch; 7-electronic switch II; 8-frozen soil sample; 9-inner cavity; 10-a heat sink; 11-internal thermometers; 12-a detector; 13-outlet thermometers; 14-electronic switch number three; 15-four electronic switches; 16-a thermal imager; 17-an object stage; 18-a body; 19-a scanning bin; 20-an inlet pipe; 21-outlet pipe.
Detailed Description
The present invention will be described in further detail with reference to test examples and specific embodiments. It should be understood that the scope of the above-described subject matter of the present invention is not limited to the following examples, and any technique realized based on the contents of the present invention is within the scope of the present invention.
Example 1
Referring to fig. 1, the present embodiment provides a frozen soil CT scanning apparatus for precise temperature control, which includes a main body 18, a scanning chamber 19, a heat sink 10, an object stage 17, a radiation source 4, a detector 12, an internal thermometer 11, a thermal imager 16, an inlet tube 20, a pressure valve 2, a flow control decompressor 3, an inlet thermometer 5, an electronic switch 6, an electronic switch 7, an outlet tube 21, an outlet thermometer 13, an electronic switch 14, an electronic switch 15 and a cooling bath system 1, wherein the object stage 17 is disposed in the scanning chamber 19, the scanning chamber 19 is disposed in the main body 18, an inner chamber 9 is disposed between the scanning chamber 19 and an inner wall of the main body 18, the main body 18 is disposed between the radiation source 4 and the detector 12, the inlet tube 20 and the outlet tube 21 are respectively connected to the inner chamber 9 and the scanning chamber 19, the inlet tube 20 and the outlet tube 21 are connected to the cooling bath system 1, the cooling source is provided to the inner chamber 9 through the inlet tube 20 and the outlet tube 21, the cold volume is led into frozen soil sample 8 of scanning storehouse 19 and is carried out the precooling, scanning storehouse 19 is provided with the cold source with the pipeline to the rethread, and then carry out the circulating refrigeration of cold source to frozen soil sample 8, make frozen soil sample 8 locate the environment whole and cool down, furthest has reduced the interference to the frozen soil, frozen soil sample 8 takes place the heat exchange with the external world when can avoiding the experiment, eliminate the moisture migration phenomenon of frozen soil sample 8, avoid frozen soil sample 8 inner structure to change, eliminate the influence to the CT scanning.
In this embodiment, the main body 18 and the scanning chamber 19 are both made of a high polymer material capable of penetrating a ray, such as polyetheretherketone, the main body 18 and the scanning chamber 19 are square or cylindrical, a cavity is arranged in the main body 18, the scanning chamber 19 is fixed in the cavity, an inner cavity 9 is formed between the outer wall of the scanning chamber 19 and the inner wall of the main body 18, an insulating material layer is coated on the inner wall of the main body 18, the main body 18 can also be made of an insulating material, the scanning chamber 19 can be made of a heat conducting material, or a heat conducting material layer; through the arrangement of the heat insulating material, the dissipation of cold energy can be reduced or avoided; the scanning bin 19 is used for placing a frozen soil sample 8, the objective table 17 is fixed at the bottom of the scanning bin 19, the thermal imager 16 is arranged beside the objective table 17, the internal thermometer 11 is fixed between the frozen soil sample 8 and the inner wall of the scanning bin 19, the inner wall of the scanning bin 19 is also provided with radiating fins 10 distributed over the inner wall, the radiating fins 10 are arranged around the inner wall of the scanning bin 19 at equal intervals with the inner wall of the top bottom, and the cooling energy transmitted by the inner cavity 9 can be quickly guided into the scanning bin 19 through the radiating fins 10, so that the maximum refrigerating efficiency is realized; the temperature inside the scanning bin 19 can be measured through the internal thermometer 11 and the thermal imager 16, and the temperature inside the scanning bin 19 is timely fed back to the flow control pressure reducer 3 to be synchronously adjusted, so that the control can be carried out in real time; a body 18 is positioned between source 4 and detector 12, and body 18 is positioned to center scan compartment 19 to ensure that radiation is detected through scan compartment 19.
In this embodiment, the scanning chamber 19 and the inner chamber 9 are respectively connected with a pipeline for circulating a cold source, the pipeline includes an inlet pipe 20 and an outlet pipe 21, the inlet pipe 20 and the outlet pipe 21 are respectively one, or two inlet pipes 20 and two outlet pipes 21 are also adopted, when two inlet pipes 20 are adopted, one is used for connecting the inner chamber 9, the other is used for connecting the scanning chamber 19, the two outlet pipes 21 are similarly, one is used for connecting the inner chamber 9, the other is used for connecting the scanning chamber 19, at this time, the cold source provided for the inner chamber 9 can be gas or liquid, the cold source provided for the scanning chamber 19 is gas, and the two are separately and independently arranged, so as to provide different cold source options; in the embodiment, the inner cavity 9 and the scanning chamber 19 share the inlet pipe 20 and the outlet pipe 21, cold air is provided through the inlet pipe 20 and the outlet pipe 21, the inlet pipe 20 is located above the outlet pipe 21, and since the fluid with higher temperature moves upwards, the cold air moves from top to bottom and the hot air moves from bottom to top through the up-and-down arrangement of the inlet pipe 20 and the outlet pipe 21, so that effective cold source circulation is formed in the scanning chamber 19; import pipe 20, cold bath system 1 is connected respectively to the one end of outlet pipe 21, cold bath system 1 adopts current confession air conditioning equipment, import pipe 20, outlet pipe 21's the other end is connected main part 18 respectively and is extended to in scanning storehouse 19, import pipe 20 is equipped with the import that provides the cold source respectively at inner chamber 9 and scanning storehouse 19, outlet pipe 21 is equipped with the export of backward flow cold source respectively at inner chamber 9 and scanning storehouse 19, the cold source export of import pipe 20 in scanning storehouse 19 is seted up, through the design of import pipe 20 and outlet pipe 21, can be respectively for inner chamber 9 and scanning storehouse 19 provide the cold source, cold source export setting through import pipe 20, avoid the cold source to blow frozen soil sample 8 directly.
In this embodiment, the inlet pipe 20 located outside the main body 18 is further provided with a pressure valve 2 and a flow control pressure reducer 3, and the cold quantity provided by the inlet pipe 20 can be adjusted through the pressure valve 2 and the flow control pressure reducer 3, so that the pressure and the flow are stable, the cold quantity is in a proper range, and the accurate control of the cold quantity and the temperature is realized; the inlet pipe 20 is provided with a first electronic switch 6 at a cold source inlet of the inner cavity 9, the inlet pipe 20 is provided with a second electronic switch 7 at a cold source outlet of the scanning bin 19, the outlet pipe 21 is provided with a third electronic switch 14 at the cold source inlet of the inner cavity 9, the outlet pipe 21 is provided with a fourth electronic switch 15 at the cold source outlet of the scanning bin 19, the four electronic switches are all existing electromagnetic valves, circuits of the four electronic switches are connected to the outer wall of the main body 18 and provided with buttons for operation, the inlet pipe 20 outside the main body 18 is provided with an inlet temperature measuring meter 5, the cold source temperature at the inlet pipe 20 can be monitored in real time through the inlet temperature measuring meter 5, the outlet pipe 21 outside the main body 18 is provided with an outlet temperature measuring meter 13, the cold source temperature at the outlet pipe 21 can be monitored in real time through the outlet temperature measuring meter 13, and the temperature is monitored to ensure that the cold quantity is maintained in a constant range; through the arrangement of the four electronic switches, the cold source outlets of the inlet pipe 20 and the return cold source outlets of the outlet pipe 21 in the inner cavity 9 and the scanning bin 19 can be respectively subjected to switch adjustment, so that the supply of the cold source in the inner cavity 9 and the supply of the cold source in the scanning bin 19 can be independently performed.
Example 2
Referring to fig. 2, the present embodiment provides a frozen soil CT scanning method for precise temperature control, which employs the frozen soil CT scanning apparatus for precise temperature control in embodiment 1, and an object stage 17 for placing a frozen soil sample 8 is disposed in a scanning chamber 19, and the scanning method includes the following steps:
s1, placing the frozen soil sample 8 in the initial state on an object stage 17, adjusting the position of a main body 18 between a radiation source 4 and a detector 12, adjusting a scanning cabin 19 to be centered in the main body 18, respectively connecting an inlet pipe 20 and an outlet pipe 21 with the cold bath system 1, ensuring that the scanning cabin 19 is positioned between the radiation source 4 and the detector 12 after the device is installed, and checking the safety of the device;
s2, turning on the first electronic switch 6 and the third electronic switch 14, turning off the second electronic switch 7 and the fourth electronic switch 15, then turning on the cold bath system 1, adjusting output cold through the pressure valve 2, adjusting the flow control pressure reducer 3 through the inlet temperature detector 5, ensuring that the cold is in a preset temperature range, enabling the cold source to enter the inner cavity 9 through a pipeline to start circulation, integrally cooling the scanning bin 19, pre-cooling the frozen soil sample 8, and aiming at effectively avoiding moisture migration caused by single-point super-cooling on the soil sample and influencing the later microscopic analysis result;
s3, the scanning bin 19 and the radiating fins 10 uniformly transmit cold in the inner cavity 9 to the frozen soil sample 8, the temperature in the scanning bin 19 is uniformly reduced to an experimental temperature through precooling, the moisture in the frozen soil sample 8 is subjected to phase change, the frozen soil sample 8 is not subjected to moisture migration, the second electronic switch 7 and the fourth electronic switch 15 are turned on, a cold source enters the scanning bin 19 through a pipeline and forms effective circulation in the scanning bin 19, the circulation is continued for a period of time until the internal temperature measuring meter 11 displays a temperature target value, the scanning bin 19 is subjected to final cooling, the temperature of the frozen soil sample 8 can be uniformly reduced to freezing through the final cooling, and the moisture migration in the frozen soil sample 8 caused by temperature difference is avoided;
s4, adjusting the cold quantity and the flow rate through the flow control decompressor 3, performing constant temperature control, ensuring that the temperature of the internal thermometer 11 reaches a target value, the difference value between the inlet thermometer 5 and the outlet thermometer 13 is smaller than a required value, simultaneously, the internal temperature of the frozen soil sample 8 displayed by the thermal imager 16 is uniform, ensuring that the temperature in the scanning bin 19 is maintained in a preset range for a period of time, and completing the cooling and freezing process of the frozen soil sample 8;
and S5, starting CT scanning after the temperature displayed by the internal thermometer 11 does not fluctuate to obtain a full-section three-dimensional image of the frozen soil sample 8, closing the cold bath system 1 after scanning is finished, closing the flow control pressure reducer 3, the first electronic switch 6, the second electronic switch 7, the third electronic switch 14 and the fourth electronic switch 15 after the pressure valve 2 is reduced to zero, and taking out the frozen soil sample 8.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. The utility model provides a frozen soil CT scanning device for accurate accuse temperature, its characterized in that, the device includes ray source, detector, main part and scanning storehouse, the main part is established between ray source and detector, the main part can be pierced through by the ray with the scanning storehouse, be equipped with the cavity in the main part, the scanning storehouse is established in the cavity, be used for placing the frozen soil sample in the scanning storehouse, scanning storehouse outer wall with be the inner chamber between the main part inner wall, the scanning storehouse with the inner chamber is connected with the pipeline that is used for the cold source circulation respectively, still be equipped with the temperature measuring device who is used for surveying the temperature in the scanning storehouse.
2. The frozen soil CT scanning device for accurate temperature control as recited in claim 1, wherein the pipeline for cold source circulation comprises an inlet pipe and an outlet pipe, one end of the inlet pipe and one end of the outlet pipe are respectively connected with the cold bath system, the other end of the inlet pipe and the other end of the outlet pipe are respectively connected with the main body and extend into the scanning bin, the inlet pipe is respectively provided with an inlet for providing a cold source in the inner cavity and the scanning bin, the outlet pipe is respectively provided with an outlet for a backflow cold source in the inner cavity and the scanning bin, the inlet pipe is positioned above the outlet pipe, and the outlet of the cold source of the inlet pipe in the scanning bin is opened upwards.
3. The frozen soil CT scanning device for precise temperature control according to claim 2, wherein the main body is provided with a heat insulating material layer or made of heat insulating material, and the scanning chamber is provided with a heat conducting material layer or made of heat conducting material.
4. The frozen soil CT scanning device for accurate temperature control according to claim 2, wherein the inlet pipe is provided with a pressure valve and a flow control pressure reducer.
5. The frozen soil CT scanning device for precise temperature control according to claim 2, wherein the inner wall of the scanning chamber is further provided with cooling fins extending over the inner wall.
6. The frozen soil CT scanning device for precise temperature control according to claim 2, wherein the temperature measuring device comprises an internal temperature meter and a thermal imager.
7. The frozen soil CT scanning device for accurate temperature control as claimed in claim 2, wherein the inlet tube is provided with a first electronic switch at the cold source inlet of the inner cavity, and the inlet tube is provided with a second electronic switch at the cold source outlet of the scanning bin; the cold source inlet of the inner cavity of the outlet pipe is provided with a third electronic switch, and the cold source outlet of the scanning bin of the outlet pipe is provided with a fourth electronic switch.
8. The CT scanning device for frozen soil with accurate temperature control as claimed in claim 2, wherein the inlet pipe outside the main body is provided with an inlet thermometer, and the outlet pipe outside the main body is provided with an outlet thermometer.
9. The frozen soil CT scanning device for accurate temperature control according to any one of claims 2 to 8, wherein two inlet tubes and two outlet tubes are adopted, one inlet tube and one outlet tube are respectively connected to the inner cavity, and the other inlet tube and the other outlet tube are respectively connected to the scanning bin.
10. A frozen soil CT scanning method for accurate temperature control adopts the frozen soil CT scanning device for accurate temperature control of claim 9, an objective table for placing frozen soil samples is arranged in the scanning bin, and the method is characterized by comprising the following steps:
s1, placing the frozen soil sample in the initial state on an object stage, adjusting the position of a main body between the ray source and the detector, adjusting a scanning cabin to be centered in the main body, and connecting the inlet pipe and the outlet pipe with the cold bath system respectively to finish the installation of the device;
s2, turning on a first electronic switch and a third electronic switch, turning off a second electronic switch and a fourth electronic switch, then turning on a cold bath system, adjusting output cold through a pressure valve, adjusting a flow control pressure reducer through an inlet temperature detector, ensuring that the cold is in a preset temperature range, enabling the cold to enter an inner cavity through a pipeline to start circulation, integrally cooling a scanning cabin, and pre-cooling a frozen soil sample;
s3, uniformly reducing the temperature in the scanning bin to the experimental temperature through precooling, enabling the moisture in the frozen soil sample to be in phase change, enabling the frozen soil sample not to be subjected to moisture migration, then turning on the second electronic switch and the fourth electronic switch, and enabling the cold source to enter the scanning bin through a pipeline;
s4, adjusting the cold quantity and the flow rate through the flow control pressure reducer, ensuring that the temperature of the internal temperature detector reaches a target value, the difference value between the inlet temperature detector and the outlet temperature detector is smaller than a required value, and simultaneously, the internal temperature of the frozen soil sample displayed by the thermal imaging instrument is uniform, thereby completing the freezing process of the frozen soil sample;
and S5, starting CT scanning after the temperature displayed by the internal thermometer does not fluctuate to obtain a full-section three-dimensional image of the frozen soil sample, closing the cold bath system after scanning is finished, closing the flow control pressure reducer, the first electronic switch, the second electronic switch, the third electronic switch and the fourth electronic switch after the pressure valve is reduced to zero, and taking out the frozen soil sample.
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