Device capable of freezing and fixing sample in supercooled liquid nitrogen

Abstract

The utility model provides a device capable of freezing and fixing a sample in supercooled liquid nitrogen, which comprises a supercooled liquid nitrogen tank, a sealing cover, a sample feeding rod, a sample seat support and a mechanical pump, the supercooled liquid nitrogen tank comprises an inner-layer foam tank and an outer-layer metal tank, a first accommodating chamber is arranged in the metal tank, the foam tank is arranged at the bottom of the first accommodating chamber, and the sealing cover is arranged on the outer-layer metal tank. A second accommodating cavity is formed in the foam tank; the sealing cover is hermetically connected to the top of the supercooled liquid nitrogen tank; the sealing cover comprises a sample injection sealing cover and a visible sealing cover; the sample seat bracket is connected to the bottom of the sample feeding rod, the lower part of the sample feeding rod is inserted into the supercooled liquid nitrogen tank through the sample injection sealing cover, and the sample seat bracket loaded with a to-be-frozen sample is pushed into the bottom of the second accommodating chamber for freezing; the mechanical pump is connected with one side of the metal tank, and the other side of the metal tank is connected with a deflation valve. According to the utility model, the water-containing sample is quickly frozen and fixed with high quality by using the supercooled liquid nitrogen, so that ice crystals in the sample are effectively prevented from being generated, and the real micro-morphology of the sample is reserved to the greatest extent.

Description

Technical Field

[0001] The utility model relates to the technical field of sample preparation for cryo-scanning electron microscopy, in particular to a device capable of realizing freezing and fixing of samples in supercooled liquid nitrogen. Background Art

[0002] When analyzing samples containing water or liquid by high-vacuum scanning electron microscopy, drying treatment must be carried out. However, the existing drying methods will more or less damage the microscopic morphology and structure of the samples. Cryo-scanning electron microscopy can avoid the problems caused by sample drying by freezing and fixing the liquid in the samples. However, due to the limited freezing rate of the conventional boiling liquid nitrogen bath freezing and fixing method, a large number of ice crystals are easily formed inside the samples rich in water content, thus interfering with the analysis of the microscopic structure and morphology of the samples. The supercooled liquid nitrogen freezing and fixing method can effectively solve this problem. However, the current mainstream commercial cryo-sample preparation products (such as the Leica cryo-sample preparation product line) lack corresponding supercooled liquid nitrogen sample preparation equipment. Therefore, developing a set of efficient and convenient supercooled liquid nitrogen freezing and sample preparation device is very meaningful for complementing the existing commercial technical routes. Summary of the Utility Model

[0003] In view of the above-mentioned technical problems, a device capable of realizing freezing and fixing of samples in supercooled liquid nitrogen is provided. The technical means adopted by the utility model are as follows:

[0004] A device capable of realizing freezing and fixing of samples in supercooled liquid nitrogen, comprising: a supercooled liquid nitrogen tank, a sealing cover, a sample delivery rod, a sample holder bracket and a mechanical pump. The supercooled liquid nitrogen tank includes an inner foam tank and a metal tank. The inside of the metal tank has a first accommodation chamber, and the foam tank is placed at the bottom of the first accommodation chamber. The inside of the foam tank has a second accommodation chamber communicating with the first accommodation chamber;

[0005] The sealing cover is hermetically connected to the top of the supercooled liquid nitrogen tank, forming a sealed space with the inside of the supercooled liquid nitrogen tank; the sealing cover includes a sample injection sealing cover and a visual sealing cover;

[0006] The sample holder bracket is connected to the bottom of the sample delivery rod. The lower part of the sample delivery rod is inserted into the supercooled liquid nitrogen tank through the sample injection sealing cover, and is used to push the sample holder bracket loaded with the sample to be frozen into the second accommodation chamber for freezing;

[0007] The mechanical pump is connected to one side of the metal tank and is used to evacuate the inside of the supercooled liquid nitrogen tank; the other side of the metal tank is connected with a gas release valve, and the gas release valve communicates with the atmosphere.

[0008] Furthermore, both the foam tank and the metal tank are cylindrical tanks with sealed bottoms; there is a gap between the foam tank and the metal tank; a sample holder support groove is provided at the bottom of the foam tank, which is used to hold the sample holder support, and the size of the sample holder support groove matches that of the sample holder support; horizontal metal lifting rods are provided on both sides of the top of the foam tank.

[0009] Furthermore, a vacuum interface is provided on one side of the metal tank, and the vacuum interface is connected to a mechanical pump through a pipeline, and a vacuum gauge is installed on this pipeline; a plurality of fixed buckle devices are provided on the outer wall of the metal tank for locking and connecting with the sealing cover.

[0010] Furthermore, the sampling sealing cover is a metal cover plate, and a sampling sealing cover round hole is provided on the sampling sealing cover for inserting the sample delivery rod. An annular sample delivery rod sealing groove is provided on the inner wall of the sampling sealing cover round hole, and a sample delivery rod sealing ring is placed in the sample delivery rod sealing groove to achieve radial sealing with the sample delivery rod.

[0011] Furthermore, a sampling sealing cover shoulder is provided at the bottom of the sampling sealing cover, which is used to cooperate with the top of the metal tank for connection. A sampling sealing cover shoulder groove is provided on the outside of the sampling sealing cover shoulder, and a sampling sealing cover sealing ring is placed in the sampling sealing cover shoulder groove to achieve radial sealing with the metal tank;

[0012] A plurality of sampling sealing cover buckle fixing heads are circumferentially arranged on the outside of the sampling sealing cover for connecting with a plurality of fixed buckle devices on the metal tank.

[0013] Furthermore, the visual sealing cover includes a connected visual inner cover and outer cover. The visual inner cover is composed of a circular transparent visual window and an annular pressing plate. A plurality of pressing plate screw holes are provided at the outer edge of the annular pressing plate, and bolts are connected in the pressing plate screw holes. The bolts are connected to the upper part of the middle of the outer cover, and the connection between the annular pressing plate and the outer cover is achieved through the pressing plate screw holes and the bolts. The visual window is installed between the annular pressing plate and the outer cover, and the outer cover is used for airtight connection with the top of the metal tank; the annular pressing plate is a metal ring.

[0014] Further, the outer cover is an annular metal cover. At the center position of the outer cover, there are two stepped circular grooves, namely an inner groove and an outer groove located above the inner groove. The visual window is placed in the inner groove. A circular hole is opened at the center of the inner groove, and the circular hole communicates with the first accommodation chamber, the inner groove, and the outer groove. On the upper surface of the inner groove adjacent to the circular hole, there is a visual window sealing groove, and a visual window sealing ring is placed in the visual window sealing groove. The lower surface of the visual window is in sealed contact with the visual window sealing ring. Along the circumferential direction of the outer edge area of the outer groove, there are a plurality of outer cover screw holes, and the plurality of outer cover screw holes are respectively coaxial with a plurality of pressing plate screw holes. A bolt is jointly connected and matched in the outer cover screw hole and the pressing plate screw hole, and the connection between the annular pressing plate and the outer cover is realized through the bolt, the pressing plate screw hole, and the outer cover screw hole.

[0015] Further, a shoulder is provided at the bottom of the outer cover, and the shoulder of the outer cover is inserted into the top of the metal can for mating connection with the top of the metal can. A shoulder sealing groove is provided on the outer side of the shoulder of the outer cover, and a shoulder sealing ring is placed in the shoulder sealing groove to achieve radial sealing with the metal can.

[0016] A plurality of outer cover snap fixing heads are provided along the circumferential direction on the outer side of the outer cover for fixedly connecting with a plurality of fixing snap devices on the metal can.

[0017] Further, the sample delivery rod includes a rod body, a fixing head, a limit bolt, and a handle. The handle is installed at the top of the rod body. An insertion hole penetrating the rod body is provided at a position 20 - 30 mm away from the bottom of the rod body for inserting the limit bolt.

[0018] A sample delivery rod screw hole is provided at the bottom of the rod body. The fixing head is a detachable spindle-shaped metal block and is fixed in the sample delivery rod screw hole by screws.

[0019] The rod body is a metal round rod, and the limit bolt is a metal cylinder with a pull ring at the top.

[0020] Further, the main body of the sample holder bracket is a cubic metal base. On both sides of the sample holder bracket, there are rectangular sheet-like protrusions protruding laterally, and square sample table grooves are opened on the protrusions for placing the stud-legged sample table.

[0021] A sample table groove insertion hole is opened at the center of the sample table groove. A cubic fixing head slot hollowed out laterally is provided on the rectangular top of the sample holder bracket for placing the fixing head of the sample delivery rod. The upper surface of the fixing head slot is not completely sealed and is provided with a fixing head insertion port for inserting the fixing head of the sample delivery rod. A screw is inserted through the center of the bottom of the sample holder bracket, and the screw is inserted into the fixing head of the sample delivery rod and the sample delivery rod screw hole to realize the fixed connection of the sample holder bracket, the fixing head of the sample delivery rod, and the rod body.

[0022] Compared with the prior art, the utility model has the following advantages:

[0023] 1. Through the design of the replaceable sealing cover, the utility model can effectively monitor the formation process of supercooled liquid nitrogen via the visible sealing cover and effectively control the rapid and accurate sample injection via the sample injection sealing cover. By using a high-power mechanical pump to evacuate the liquid nitrogen stored in the foam tank in the device, the rapid preparation of supercooled liquid nitrogen is realized.

[0024] 2. The utility model uses supercooled liquid nitrogen to quickly and highly quality freeze-fix the water-containing sample, effectively preventing the generation of ice crystals in the sample and retaining its true microscopic morphology to the greatest extent.

[0025] 3. The utility model has a small and compact structure, is easy to operate, and has strong flexibility, which can effectively supplement the sample preparation unit of some existing commercial scanning electron microscope cryogenic transfer devices.

[0026] 4. Through the design of the sample delivery rod and its fixed head, the utility model ensures that the sample is quickly and accurately pushed into the groove of the sample stage at the bottom of the foam tank, avoiding the tipping and collision of the sample stage in the supercooled liquid nitrogen, causing sample damage, and can be used in cooperation with various types of pin-legged sample stages.

[0027] Based on the above reasons, the utility model can be widely promoted in the fields of sample freeze-fixation and the like. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a sectional view of the device of the supercooled liquid nitrogen tank of the present utility model with a sample injection sealing cover.

[0030] Figure 2 It is a three-dimensional external view of the device of the supercooled liquid nitrogen tank of the present utility model with a sample injection sealing cover.

[0031] Figure 3 It is a sectional view of the supercooled liquid nitrogen tank of the present utility model with a visible sealing cover.

[0032] Figure 4 It is a three-dimensional external view of the supercooled liquid nitrogen tank of the present utility model with a visible sealing cover.

[0033] Figure 5 It is a sectional view of the outer cover of the visible sealing cover of the present utility model.

[0034] Figure 6 This is a three-dimensional external view of the sample delivery rod of the present utility model and the sample holder bracket loaded with the sample stage.

[0035] Figure 7 This is a sectional view of the connection state between the sample holder bracket of the present utility model and the fixed head of the sample delivery rod.

[0036] In the figure: 1. Sub-cooled liquid nitrogen tank; 2. Sealing cover; 3. Sample delivery rod; 4. Sample holder bracket;

[0037] 11. Foam tank; 12. Metal tank; 111. Groove of the sample holder bracket; 112. Metal lifting rod; 113. Second accommodation chamber; 121. Vacuum interface; 122. Vacuum gauge; 123. Air release valve; 124. Fixed buckle device; 125. First accommodation chamber;

[0038] 21. Sampling sealing cover; 22. Visual sealing cover; 211. Round hole of the sampling sealing cover; 2111. Sealing groove of the sample delivery rod; 2112. Sealing ring of the sample delivery rod; 212. Shoulder of the sampling sealing cover; 213. Snap fixed head of the sampling sealing cover; 2121. Groove of the shoulder of the sampling sealing cover; 2122. Sealing ring of the shoulder of the sampling sealing cover; 221. Visual inner cover; 222. Outer cover; 2211. Visual window; 2212. Ring-shaped pressing plate; 22121. Pressing plate screw hole; 2221. Outer groove; 2222. Inner groove; 2223. Round hole; 2224. Sealing groove of the visual window; 2225. Sealing ring of the visual window; 2226. Screw hole of the outer cover; 2227. Shoulder of the outer cover; 2228. Sealing groove of the shoulder of the outer cover; 2229. Sealing ring of the shoulder of the outer cover; 2230. Snap fixed head of the outer cover;

[0039] 31. Rod body; 32. Fixed head; 33. Limit bolt; 34. Handle; 311. Screw hole of the sample delivery rod; 312. Jack;

[0040] 41. Protrusion; 411. Groove of the sample stage; 412. Jack of the groove of the sample stage; 42. Slot of the fixed head; 43. Socket of the fixed head; 44. Stud-leg sample stage. Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0042] The present utility model provides as shown in the appendix Figure 1-7A device capable of realizing the freezing and fixation of samples in supercooled liquid nitrogen is a freezing sample preparation device for freezing and fixing water-containing or liquid-containing samples with supercooled liquid nitrogen, that is, a set of supercooled liquid nitrogen freezing sample preparation device for the efficient freezing and fixation of water-containing samples.

[0043] The device of the present utility model includes a supercooled liquid nitrogen tank 1, a sealing cover 2, a sample delivery rod 3, a sample holder bracket 4, and a mechanical pump (using an existing mechanical pump, not shown in the figure) for evacuating the supercooled liquid nitrogen tank; among them, the supercooled liquid nitrogen tank 1 and the sealing cover 2 are used as the main body of the freezing device to prepare supercooled liquid nitrogen and freeze and fix the sample. The supercooled liquid nitrogen tank 1 and the sealing cover 2 are used in combination to form a sealed supercooled liquid nitrogen tank for sample freezing and fixation; the sample delivery rod 3 is used to push the sample holder bracket 4 loaded with the sample to be frozen into the supercooled liquid nitrogen tank 1 for freezing; the mechanical pump is connected to the supercooled liquid nitrogen tank 1 and provides a vacuum environment for the supercooled liquid nitrogen tank 1 to prepare supercooled liquid nitrogen. Specifically, the supercooled liquid nitrogen tank 1 is the main body of the freezing sample preparation, and forms a sealed space in cooperation with the sealing cover 2. After being evacuated by a high-power mechanical pump, supercooled liquid nitrogen is quickly obtained. The supercooled liquid nitrogen tank 1 is composed of an inner foam tank 11 and an outer metal tank 12. The inside of the outer metal tank 12 has a first accommodation chamber 125. The inner foam tank 11 is placed at the bottom of the first accommodation chamber 125. The inside of the inner foam tank 11 has a second accommodation chamber 113 communicating with the first accommodation chamber 125. The orthographic projection of the sample holder bracket 4 is within the orthographic projection range of the bottom surface of the second accommodation chamber 113. The sealing cover 2 is divided into a visual sealing cover 22 and a sample injection sealing cover 21, which respectively realize the visual monitoring of the formation process of supercooled liquid nitrogen and the quick and accurate sample injection during sample freezing. The sample delivery rod 3 used in cooperation with the sample injection sealing cover 21 can accurately send the sample to be frozen into the preset position in the supercooled liquid nitrogen foam tank 1. The sample holder bracket 4 fixed at the bottom of the sample delivery rod 3 can realize the quick separation from the sample delivery rod 3. The present utility model uses supercooled liquid nitrogen to quickly and highly quality freeze and fix water-containing samples, effectively preventing the generation of ice crystals in the samples and retaining their true microscopic morphology to the greatest extent. The present utility model realizes the effective monitoring of the formation process of supercooled liquid nitrogen through the visual sealing cover and the effective control of quick and accurate sample injection through the sample injection sealing cover through the replaceable sealing cover design. A high-power mechanical pump is used to evacuate the liquid nitrogen stored in the foam tank in the device to realize the quick preparation of supercooled liquid nitrogen.

[0044] During operation, first, a sealed environment is formed by the cooperation of the supercooled liquid nitrogen tank 1 and the sealing cover 2. Then, the supercooled liquid nitrogen tank 1 is evacuated by the mechanical pump to prepare supercooled liquid nitrogen. Next, the sample holder bracket 4 is sent into the supercooled liquid nitrogen tank 1 through the sample delivery rod 3 for sample freezing and fixation.

[0045] The visual sealing cover 22 is used to cooperate with the supercooled liquid nitrogen tank 1 before sample cryo-fixation, monitor the state change of liquid nitrogen in the vacuum environment through the visual window. After determining the formation of supercooled liquid nitrogen, quickly break the vacuum and replace the visual sealing cover 22 with the sample injection sealing cover 21 to connect with the supercooled liquid nitrogen tank 1, and send the sample holder bracket 4 into the supercooled liquid nitrogen tank 1 through the sample delivery rod 3.

[0046] As a preferred embodiment, the supercooled liquid nitrogen tank 1 is composed of an inner layer foam tank 11 and an outer layer metal tank 12; the foam tank 11 is a cylindrical tank with a closed bottom, with an inner diameter of 70 - 90 mm, an outer diameter of 90 - 130 mm, a height of 100 - 150 mm, and a wall thickness of 10 - 20 mm; the outer layer metal tank 12 is also a cylindrical tank with a closed bottom, with an inner diameter of 100 - 150 mm, an outer diameter of 110 - 170 mm, a height of 120 - 170 mm, and a wall thickness of 5 - 10 mm; there is a gap between the outer wall of the foam tank 11 and the inner wall of the metal tank 12, with a spacing of 5 - 10 mm; the bottom of the foam tank 11 is provided with a sample holder bracket groove 111 for clamping the sample holder bracket 4, and the size of the sample holder bracket groove 111 matches that of the sample holder bracket 4, with a groove depth of 2 - 3 mm; near the top of the foam tank 11, there are 2 horizontal metal lifting rods 112 to facilitate lifting the foam tank 11 out of the metal tank 12.

[0047] As a preferred embodiment, on one side of the outer layer metal tank 12 of the supercooled liquid nitrogen tank 1, there is a protruding vacuum interface 121 for connecting a mechanical pump and a vacuum gauge 122 (using an existing vacuum gauge), and on the other side of the metal tank 12, there is a protruding air release valve 123 (using an existing valve) for connecting to the atmosphere to break the vacuum; on the outer wall of the metal tank 12, there are 4 fixed buckle devices 124 (the fixed buckle device 124 uses an existing buckle structure) symmetrically arranged along the circumferential direction for locking connection with the sealing cover 2.

[0048] As a preferred embodiment, the sealing cover 2 is divided into two types: a sample injection sealing cover 21 and a visual sealing cover 22, both of which can be used in cooperation with the metal can 12 to achieve sealing; the sample injection sealing cover 21 is a metal cover plate, with a sample injection sealing cover round hole 211 in the center for inserting the sample delivery rod 3, and the radial sealing between the two is achieved through a sealing ring placed inside the sample injection sealing cover round hole 211. Through the design of the bottom shoulder and the sealing ring, it is hermetically connected to the metal can 12 with a clearance fit. Specifically, an annular sample delivery rod sealing groove 2111 is provided on the inner wall of the sample injection sealing cover round hole 211 for placing the sample delivery rod sealing ring 2112. The sample delivery rod sealing ring 2112 is tightly sleeved on the outer wall of the sample delivery rod 3 to achieve the radial sealing between the sealing cover 21 and the sample delivery rod 3; a circle of sample injection sealing cover shoulders 212 is provided at the bottom of the sample injection sealing cover 21 for connecting with the top of the metal can 12 with a clearance fit. An annular sample injection sealing cover shoulder groove 2121 is provided on the outside of the sample injection sealing cover shoulder 212 for placing the sample injection sealing cover sealing ring 2122. The sample injection sealing cover sealing ring 2122 is in close contact with the inner wall top of the metal can 12 to achieve the radial sealing between the sample injection sealing cover 21 and the metal can 12; the outer diameter of the sample injection sealing cover 21 is 110 - 170 mm, the diameter of the sample injection sealing cover shoulder 212 is 100 - 150 mm, and the diameter of the sample injection sealing cover round hole 211 is 7 - 10 mm; the thickness of the sample injection sealing cover 21 is 8 - 10 mm, and the thickness including the shoulder part is 13 - 15 mm. Four sample injection sealing cover buckle fixing heads 213 are circumferentially arranged on the outside of the sample injection sealing cover 21 for connecting with four fixing buckle devices 124 on the metal can 12.

[0049] As a preferred embodiment, the visual sealing cover 22 is composed of a visual inner cover 221 and an outer cover 222; the visual inner cover 221 is composed of a circular transparent visual window 2211 (with visual function) and an annular pressing plate 2212, and is used in cooperation with the outer cover 222 to achieve the sealing of the metal can 12; the material of the visual window 2211 is sapphire, with a diameter of 80 - 100 mm and a thickness of 8 mm. The annular pressing plate 2212 is a metal ring, with an inner diameter of 70 - 90 mm and an outer diameter of 105 - 125 mm; four pressing plate screw holes 22121 are provided near the outer edge of the annular pressing plate 2212 for connecting with the outer cover 222 to achieve the fixed connection between the visual inner cover 221 and the outer cover 222. A bolt is fitted in the pressing plate screw hole 22121, and this bolt is connected to the upper part of the middle of the outer cover 222. The outer cover 222 is used for hermetically connecting with the top of the metal can 12.

[0050] As a preferred embodiment, the outer cover 222 of the visible sealing cover 22 is an annular metal cover with a central opening for placing the visible inner cover 221. Through the design of the bottom shoulder and the sealing ring, it is hermetically connected with the metal can 12 in a clearance fit, and 4 outer cover snap fixing heads 2230 (the outer cover snap fixing heads 2230 adopt the existing snap fixing head structure) are symmetrically arranged along the circumferential direction on the outside for connecting with the 4 fixing snap devices 124 on the metal can 12. Specifically, there are two stepped circular grooves, an outer groove 2221 and an inner groove 2222, which are connected, at the central position of the outer cover 222. The outer groove 2221 is located above the inner groove 2222. The visible window 2211 is placed in the inner groove 2222. A circular hole 2223 is opened at the center of the inner groove 2222. The circular hole 2223 communicates with the first accommodation chamber 125, and at the same time communicates with the outer groove 2221 and the inner groove 2222. The circular hole 2223, the inner groove 2222 and the outer groove 2221 penetrate through the axial middle part of the entire outer cover (222); on the upper surface of the inner groove 2222 adjacent to the circular hole 2223, there is a visible window sealing groove 2224 (annular groove) for placing the visible window sealing ring 2225. The lower surface of the visible window 2211 is in sealing contact with the visible window sealing ring 2225, and the upper surface of the visible window 2211 is in close contact with the lower surface of the annular pressing plate 2212; 4 outer cover screw holes 2226 are symmetrically arranged along the circumferential direction in the outer edge area of the outer groove 2221. The 4 outer cover screw holes 2226 are respectively coaxial with the 4 pressing plate screw holes 22121. A bolt is jointly connected in the outer cover screw hole 2226 and the pressing plate screw hole 22121. The connection between the annular pressing plate 2212 and the outer cover 222 is realized through the bolt, the pressing plate screw hole 22121 and the outer cover screw hole 2226; at the bottom of the outer cover 222, there is a circle of outer cover shoulders 2227 inserted into the top of the metal can 12 for connecting with the top of the metal can 12 in a clearance fit. On the outside of the outer cover shoulders 2227, there is a circle of outer cover shoulder sealing grooves 2228 for placing the outer cover shoulder sealing rings 2229. The outer cover shoulder sealing rings 2229 are in close contact with the inner wall top of the metal can 12 to realize the radial sealing between the outer cover 222 and the metal can 12; the diameter of the outer cover 222 is 110 - 170 mm, the diameter of the outer groove 2221 is 105 - 125 mm, the diameter of the inner groove 2222 is 95 - 115 mm, the diameter of the central circular hole 2223 is 70 - 90 mm, the diameter of the outer cover shoulders 2227 is 100 - 150 mm, the thickness of the outer ring part of the outer cover 222 is 15 - 20 mm, and the thickness of the inner ring including the shoulder part is 20 - 28 mm; 4 outer cover snap fixing heads 2230 are symmetrically arranged along the circumferential direction on the outside of the outer cover 222 for connecting with the 4 fixing snap devices 124 on the metal can 12.

[0051] As a preferred embodiment, the sample delivery rod 3 is composed of a rod body 31, a fixing head 32, a limit bolt 33 and a handle 34; the rod body 31 is a metal round rod with a length of 160 - 210 mm and a diameter of 7 - 10 mm, and a sample delivery rod screw hole 311 is provided at the bottom; a jack 312 penetrating the rod body is provided at a position 20 - 30 mm away from the bottom of the rod body 31 for inserting the limit bolt 33; the fixing head 32 is a detachable spindle-shaped metal block, which is fixed in the sample delivery rod screw hole 311 at the bottom of the rod body 31 by screws; the length of the fixing head 32 is 10 - 12 mm, the width is 5 - 7 mm, and the thickness is 3 - 5 mm; the limit bolt 33 is a metal cylinder with a pull ring at the top, the diameter is 5 mm, and the length is 20 - 30 mm.

[0052] As a preferred embodiment, the sample holder bracket 4 is used to place the nail-leg sample stage 44 loaded with the sample to be frozen, and can be quickly separated from and connected to the sample rod 3. The main body of the sample holder bracket 4 is a cubic metal base, the length of the main body is 18 - 24 mm, the width is 15 - 18 mm, and rectangular sheet-like protrusions 41 protruding laterally are provided on both sides. Each of the protrusions 41 is provided with a square sample stage groove 411 with a diameter of 12 - 15 mm and a depth of 3 mm for placing the nail-leg sample stage 44; a round hole with a diameter of 3 mm (sample stage groove jack 412) is opened at the center of the sample stage groove 411; a cubic fixing head slot 42 hollowed out laterally is provided at the rectangular top of the sample holder bracket 4 for placing the sample delivery rod fixing head 32, and its upper surface is not completely sealed, leaving an opening (fixing head socket 43) for inserting the sample delivery rod fixing head 32, and a screw is inserted through the center of the bottom of the sample holder bracket 4, and the screw is inserted into the sample delivery rod fixing head 32 and the sample delivery rod screw hole 311 from bottom to top in sequence to realize the fixed connection of the sample holder bracket 4, the sample delivery rod fixing head 32 and the rod body 31; the total length of the sample holder bracket 4 is 50 mm, the height is 20 - 30 mm, the width is 15 - 18 mm, wherein the length of the rectangular sheet-like protrusion 41 is 13 - 16 mm, the thickness is 5 mm, the length of the fixing head slot 42 is 11 - 13 mm, the depth is 12 - 15 mm, and the height is 4 - 6 mm.

[0053] As a preferred embodiment, the materials of the subcooled liquid nitrogen metal tank 12, the sealing cover 2, the sample delivery rod 3 and the metal lifting rod 112 of the foam tank 11 are all one of aluminum alloy or stainless steel; the material of the sample holder bracket 4 is one of red copper or brass; the material of the foam tank 11 is polystyrene foam.

[0054] Example 1

[0055] In this embodiment, the inner foam tank 11 is a cylindrical tank with a sealed bottom end, having an inner diameter of 70 mm, an outer diameter of 90 mm, a height of 100 mm, and a wall thickness of 10 mm; the outer metal tank 12 is also a cylindrical tank with a sealed bottom end, having an inner diameter of 100 mm, an outer diameter of 110 mm, a height of 120 mm, and a wall thickness of 5 mm; there is a gap between the foam tank 11 and the metal tank 12, with a spacing of 5 mm; the size of the sample holder bracket groove 111 matches that of the sample holder bracket 4. The length of the sample holder bracket groove 111 at the bottom of the foam tank 11 is 50 mm, the width is 15 mm, and the groove depth is 2 mm (the size of the sample holder bracket 4 is: the total length is 50 mm and the width is 15 mm); there are 2 horizontal metal lifting rods 112 near the top of the foam insulation tank 11 to facilitate lifting the foam insulation tank 11 out of the metal tank 12.

[0056] On one side of the metal tank body 12, a vacuum interface 121 is designed for connecting a mechanical pump and a vacuum gauge 122, and on the other side, an extended air release valve 123 is designed for communicating with the atmosphere to break the vacuum; four fixed buckle devices 124 are symmetrically arranged along the circumferential direction on the outer wall of the metal tank 12 for locking and connecting with the sealing cover 2.

[0057] The sealing cover 2 is designed with two types: an injection sealing cover 21 and a visual sealing cover 22, both of which can be used in cooperation with the metal tank 12 to achieve sealing; the injection sealing cover 21 is a metal cover plate, with a circular injection sealing cover round hole 211 in the center for inserting the sample delivery rod 3, and an annular sample delivery rod sealing groove 2111 is provided on the inner wall of the hole for placing the sample delivery rod sealing ring 2112 to achieve radial sealing with the sample delivery rod 3; at the bottom of the injection sealing cover 21, there is a circle of injection sealing cover shoulder 212 for clearance fit connection with the top of the metal tank 12; a circle of grooves 2121 is provided on the outside of the injection sealing cover shoulder 212 for placing the injection sealing cover sealing ring 2122 to achieve radial sealing with the metal tank 12; the outer diameter of the injection sealing cover 21 is 110 mm, the diameter of the injection sealing cover shoulder 212 is 100 mm, and the diameter of the injection sealing cover round hole 211 is 7 mm; the thickness of the injection sealing cover 21 is 8 mm, and the thickness including the shoulder part is 13 mm.

[0058] The visual sealing cover 22 is composed of a visual inner cover 221 and an outer cover 222; the visual inner cover 221 is composed of a circular transparent visual window 2211 and an annular pressing plate 2212, and is used in cooperation with the outer cover 222 to achieve the sealing of the metal tank 12; the material of the visual window 2211 is sapphire, with a diameter of 80 mm and a thickness of 8 mm. The annular pressing plate 2212 is a metal ring, with an inner diameter of 70 mm and an outer diameter of 105 mm; four pressing plate screw holes 22121 are provided near the outer edge of the annular pressing plate 2212 for fixed connection of the visual inner cover 221 and the outer cover 222 in cooperation with the outer cover 222.

[0059] The outer cover 222 is an annular metal cover, with two stepped circular grooves (outer groove 2221 and inner groove 2222) provided at the central position. A round hole 2223 is opened at the center of the inner groove 2222; an annular groove (visual window sealing groove 2224) is provided on the upper surface of the inner groove 2222 adjacent to the round hole 2223 for placing the visual window sealing ring 2225; four outer cover screw holes 2226 are symmetrically arranged along the circumferential direction on the upper edge of the outer groove 2221; a circle of outer cover shoulder 2227 is provided at the bottom of the outer cover 222 for clearance fit connection with the top of the metal can 12, and a circle of outer cover shoulder sealing groove 2228 is provided on the outside of the outer cover shoulder 2227 for placing the outer cover shoulder sealing ring 2229 to achieve radial sealing with the metal can 12; the diameter of the outer cover 222 is 110 mm, the diameter of the outer groove 2221 is 105 mm, the diameter of the inner groove 2222 is 95 mm, the diameter of the central round hole 2223 is 70 mm, the diameter of the outer cover shoulder 2227 is 100 mm, the thickness of the outer ring part of the outer cover 222 is 15 mm, and the thickness of the inner ring including the shoulder part is 20 mm; four outer cover buckle fixing heads 2230 are symmetrically arranged along the circumferential direction on the outside of the outer cover 222 for connecting with the four fixing buckle devices 124 on the metal can 12.

[0060] The sample delivery rod 3 is composed of a rod body 31, a fixing head 32, a limit bolt 33 and a handle 34; the rod body 31 is a metal round rod with a length of 160 mm and a diameter of 7 mm, and a sample delivery rod screw hole 311 is provided at the bottom; a jack 312 penetrating the rod body is provided at a position 20 mm away from the bottom of the rod body 31 for inserting the limit bolt 33; the fixing head 32 is a detachable spindle-shaped metal block, which is fixed in the sample delivery rod screw hole 311 at the bottom of the rod body 31 by screws; the length of the fixing head 32 is 10 mm, the width is 5 mm, and the thickness is 3 mm; the limit bolt 33 is a metal cylinder with a pull ring at the top, with a diameter of 5 mm and a length of 20 mm.

[0061] The main body of the sample seat bracket 4 is a cubic metal base, with a length of 18 mm, a width of 15 mm for the main body, and rectangular sheet-like protrusions 41 protruding laterally on both sides. Square sample table grooves 411 with a diameter of 12 mm and a depth of 3 mm are opened on each of the protrusions 41 for placing the nail leg sample table 44; a round hole with a diameter of 3 mm (sample table groove jack 412) is opened at the center of the sample table groove 411; a cubic fixing head slot 42 hollowed out laterally is provided at the rectangular top of the sample seat bracket 4 for placing the sample delivery rod fixing head 32, and its upper surface is not completely sealed, leaving an opening (fixing head socket 43) for inserting the sample delivery rod fixing head 32; the total length of the sample seat bracket 4 is 50 mm, the height is 20 mm, and the width is 15 mm. Among them, the length of the rectangular protrusion 41 is 13 mm, the thickness is 5 mm, the length of the fixing head slot 42 is 11 mm, the depth is 12 mm, and the height is 4 mm.

[0062] The materials of the subcooled liquid nitrogen metal tank 12, the sealing cover 2, the sample delivery rod 3, and the metal lifting rod 112 of the foam tank 11 are all aluminum alloy; the material of the sample holder bracket 4 is red copper; the material of the foam tank 11 is polystyrene foam.

[0063] Example 2

[0064] In this embodiment, the inner foam tank 11 is a cylindrical tank with a sealed bottom, an inner diameter of 90 mm, an outer diameter of 130 mm, a height of 150 mm, and a wall thickness of 20 mm; the outer metal tank 12 is also a cylindrical tank with a sealed bottom, an inner diameter of 150 mm, an outer diameter of 170 mm, a height of 170 mm, and a wall thickness of 10 mm; there is a gap between the foam tank 11 and the metal tank 12, and the spacing is 10 mm; the size of the sample holder bracket groove 111 matches that of the sample holder bracket 4. The length of the sample holder bracket groove 111 at the bottom of the foam tank 11 is 50 mm, the width is 18 mm, and the groove depth is 3 mm (the size of the sample holder bracket 4 is: the total length is 50 mm, and the width is 18 mm); there are 2 horizontal metal lifting rods 112 near the top of the foam heat-insulating tank 11 to facilitate lifting the foam heat-insulating tank 11 out of the metal tank 12.

[0065] One side of the metal tank body 12 is designed with a vacuum interface 121 for connecting a mechanical pump and a vacuum gauge 122, and the other side is designed with an extended air release valve 123 for communicating with the atmosphere to break the vacuum; four fixed buckle devices 124 are symmetrically arranged along the circumferential direction on the outer wall of the metal tank 12 for locking and connecting with the sealing cover 2.

[0066] The sealing cover 2 is designed with two types: an injection sealing cover 21 and a visual sealing cover 22, both of which can be used in cooperation with the metal tank 12 to achieve sealing; the injection sealing cover 21 is a metal cover plate, with a circular injection sealing cover hole 211 in the center for inserting the sample delivery rod 3, and an annular sample delivery rod sealing groove 2111 on the inner wall of the hole for placing the sample delivery rod sealing ring 2112 to achieve radial sealing with the sample delivery rod 3; there is a circle of injection sealing cover shoulders 212 at the bottom of the injection sealing cover 21 for clearance fit connection with the top of the metal tank 12; there is a circle of grooves 2121 on the outside of the injection sealing cover shoulders 212 for placing the injection sealing cover sealing ring 2122 to achieve radial sealing with the metal tank 12; the diameter of the injection sealing cover 21 is 170 mm, the diameter of the injection sealing cover shoulders 212 is 150 mm, and the diameter of the injection sealing cover circular hole 211 is 10 mm; the thickness of the injection sealing cover 21 is 10 mm, and the thickness including the shoulder part is 15 mm.

[0067] The visible sealing cover 22 is composed of a visible inner cover 221 and an outer cover 222; the visible inner cover 221 is composed of a circular transparent visible window 2211 and an annular pressing plate 2212, and is used in cooperation with the outer cover 222 to seal the metal can 12; the material of the visible window 2211 is sapphire, with a diameter of 100 mm and a thickness of 8 mm, and the annular pressing plate 2212 is a metal ring with an inner diameter of 90 mm and an outer diameter of 125 mm; there are 4 pressing plate screw holes 22121 near the outer edge of the annular pressing plate 2212, which are used in cooperation with the outer cover 222 to realize the fixed connection between the visible inner cover 221 and the outer cover 222.

[0068] The outer cover 222 is a circular ring-shaped metal cover, with two stepped circular grooves (outer groove 2221, inner groove 2222) provided at the central position, and a circular hole 2223 is opened at the center of the inner groove 2222; an annular groove (visible window sealing groove 2224) is provided on the upper surface of the inner groove 2222 adjacent to the circular hole 2223 for placing the visible window sealing ring 2225; 4 outer cover screw holes 2226 are symmetrically arranged along the circumferential direction on the upper edge of the outer groove 2221; a circle of outer cover shoulder 2227 is provided at the bottom of the outer cover 222 for clearance fit connection with the top of the metal can 12, and a circle of outer cover shoulder sealing groove 2228 is provided on the outer side of the outer cover shoulder 2227 for placing the outer cover shoulder sealing ring 2229 to realize the radial sealing with the metal can 12; the diameter of the outer cover 222 is 170 mm, the diameter of the outer groove 2221 is 125 mm, the diameter of the inner groove 2222 is 115 mm, the diameter of the central circular hole 2223 is 90 mm, the diameter of the outer cover shoulder 2227 is 150 mm, the thickness of the outer ring part of the outer cover 222 is 20 mm, and the thickness of the inner ring including the shoulder part is 28 mm; 4 outer cover buckle fixing heads 2230 are symmetrically arranged along the circumferential direction on the outer side of the outer cover 222, which are used to connect with 4 fixing buckle devices 124 on the metal can 12.

[0069] The sample delivery rod 3 is composed of a rod body 31, a fixing head 32, a limit bolt 33 and a handle 34; the rod body 31 is a metal round rod with a length of 210 mm and a diameter of 10 mm, and a sample delivery rod screw hole 311 is provided at the bottom; a through hole 312 penetrating the rod body is provided 30 mm away from the bottom of the rod body 31 for inserting the limit bolt 33; the fixing head 32 is a detachable spindle-shaped metal block, which is fixed in the sample delivery rod screw hole 311 at the bottom of the rod body 31 by screws; the length of the fixing head 32 is 12 mm, the width is 7 mm, and the thickness is 5 mm; the limit bolt 33 is a metal cylinder with a pull ring at the top, with a diameter of 5 mm and a length of 30 mm.

[0070] The main body of the sample holder bracket 4 is a cubic metal base. The length of the main body is 24 mm, the width is 18 mm, and rectangular sheet-like protrusions 41 protruding laterally are provided on both sides. Each of the protrusions 41 is provided with a square sample stage groove 411 with a diameter of 15 mm and a depth of 3 mm for placing the nail leg sample stage 44; a round hole with a diameter of 3 mm (sample stage groove insertion hole 412) is opened at the center of the sample stage groove 411; a cubic fixed head slot 42 hollowed out laterally is provided at the rectangular top of the sample holder bracket 4 for placing the sample delivery rod fixed head 32, and its upper surface is not completely sealed, leaving an opening (fixed head insertion opening 43) for inserting the sample delivery rod fixed head 32; the total length of the sample holder bracket 4 is 50 mm, the height is 30 mm, and the width is 18 mm. Among them, the length of the rectangular protrusion 41 is 16 mm, the thickness is 5 mm, the length of the fixed head slot 42 is 13 mm, the depth is 15 mm, and the height is 6 mm.

[0071] The materials of the subcooled liquid nitrogen metal tank 12, the sealing cover 2, the sample delivery rod 3, and the metal lifting rod 112 of the foam tank 11 are all stainless steel; the material of the sample holder bracket 4 is brass; the material of the foam tank 11 is polystyrene foam.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device capable of realizing cryo-fixation of samples in supercooled liquid nitrogen, characterized in that, Comprising: A subcooled liquid nitrogen tank (1), a sealing cover (2), a sample delivery rod (3), a sample holder bracket (4) and a mechanical pump. The subcooled liquid nitrogen tank (1) includes an inner foam tank (11) and an outer metal tank (12). The interior of the metal tank (12) has a first accommodation chamber (125). The foam tank (11) is placed at the bottom of the first accommodation chamber (125). The interior of the foam tank (11) has a second accommodation chamber (113) communicating with the first accommodation chamber (125). The sealing cover (2) is hermetically connected to the top of the subcooled liquid nitrogen tank (1), forming a sealed space inside the subcooled liquid nitrogen tank (1). The sealing cover (2) includes a sample injection sealing cover (21) and a visual sealing cover (22). The sample holder bracket (4) is connected to the bottom of the sample delivery rod (3). The sample delivery rod (3) is inserted into the subcooled liquid nitrogen tank (1) through the sample injection sealing cover (21) below, for pushing the sample holder bracket (4) loaded with the sample to be frozen into the second accommodation chamber (113) for freezing. The mechanical pump is connected to one side of the metal tank (12), for evacuating the interior of the subcooled liquid nitrogen tank (1). The other side of the metal tank (12) is connected with a gas release valve (123), and the gas release valve (123) communicates with the atmosphere.

2. The device for realizing cryofixation of samples in supercooled liquid nitrogen according to claim 1, wherein Both the foam tank (11) and the metal tank (12) are cylindrical tanks with sealed bottoms. There is a gap between the foam tank (11) and the metal tank (12). The bottom of the foam tank (11) is provided with a sample holder bracket groove (111), and the sample holder bracket groove (111) is used for clamping the sample holder bracket (4). The size of the sample holder bracket groove (111) matches that of the sample holder bracket (4). On both sides of the top of the foam tank (11), there are horizontal metal lifting rods (112).

3. A device for realizing cryo-fixation of samples in supercooled liquid nitrogen according to claim 1, characterized in that, One side of the metal tank (12) is provided with a vacuum interface (121). The vacuum interface (121) is connected to the mechanical pump through a pipeline, and a vacuum gauge (122) is installed on this pipeline. The outer wall of the metal tank (12) is provided with a plurality of fixed buckle devices (124), for locking and connecting with the sealing cover (2).

4. A device for realizing cryo-fixation of samples in supercooled liquid nitrogen according to claim 1, characterized in that, The sample injection sealing cover (21) is a metal cover plate. The sample injection sealing cover (21) is provided with a sample injection sealing cover round hole (211) for inserting the sample delivery rod (3). The inner wall of the sample injection sealing cover round hole (211) is provided with an annular sample delivery rod sealing groove (2111), and a sample delivery rod sealing ring (2112) is placed in the sample delivery rod sealing groove (2111) to achieve radial sealing with the sample delivery rod (3).

5. The device for realizing cryo-fixation of samples in supercooled liquid nitrogen according to claim 1 or 4, characterized in that, The bottom of the sample injection sealing cover (21) is provided with a sample injection sealing cover shoulder (212). The sample injection sealing cover shoulder (212) is used for mating connection with the top of the metal tank (12). The outer side of the sample injection sealing cover shoulder (212) is provided with a sample injection sealing cover shoulder groove (2121), and a sample injection sealing cover sealing ring (2122) is placed in the sample injection sealing cover shoulder groove (2121) to achieve radial sealing with the metal tank (12). A plurality of sample injection seal cap snap fixing heads (213) are circumferentially arranged on the outer side of the sample injection seal cap (21) for connecting with a plurality of fixing snap devices (124) on the metal can (12).

6. The device for realizing cryo-fixation of samples in supercooled liquid nitrogen according to claim 1, wherein, The visible seal cap (22) includes a connected visible inner cap (221) and an outer cap (222). The visible inner cap (221) is composed of a circular transparent visible window (2211) and an annular pressing plate (2212). A plurality of pressing plate screw holes (22121) are provided at the outer edge of the annular pressing plate (2212). A bolt is connected in cooperation with the pressing plate screw hole (22121), and this bolt is connected to the upper part of the middle of the outer cap (222). The connection between the annular pressing plate (2212) and the outer cap (222) is realized through the pressing plate screw hole (22121) and the bolt. The visible window (2211) is installed between the annular pressing plate (2212) and the outer cap (222). The outer cap (222) is used for hermetically connecting with the top of the metal can (12); the annular pressing plate (2212) is a metal ring.

7. An apparatus for cryo-fixation of samples in supercooled liquid nitrogen according to claim 6, characterized in that, The outer cap (222) is a circular ring-shaped metal cap. There are two stepped circular grooves, an inner groove (2222) and an outer groove (2221) located above the inner groove (2222), at the central position of the outer cap (222). The visible window (2211) is placed in the inner groove (2222). A circular hole (2223) is opened at the center of the inner groove (2222). The circular hole (2223) communicates with the first accommodation chamber (125), the inner groove (2222) and the outer groove (2221). A visible window sealing groove (2224) is provided on the upper surface of the inner groove (2222) adjacent to the circular hole (2223). A visible window sealing ring (2225) is placed in the visible window sealing groove (2224). The lower surface of the visible window (2211) is in sealing contact with the visible window sealing ring (2225); A plurality of outer cap screw holes (2226) are circumferentially arranged in the outer edge area of the outer groove (2221). The plurality of outer cap screw holes (2226) are respectively coaxial with the plurality of pressing plate screw holes (22121). A bolt is jointly connected in cooperation with the outer cap screw hole (2226) and the pressing plate screw hole (22121). The connection between the annular pressing plate (2212) and the outer cap (222) is realized through the bolt, the pressing plate screw hole (22121) and the outer cap screw hole (2226).

8. The device for realizing cryo-fixation of samples in supercooled liquid nitrogen according to claim 6, wherein An outer cap shoulder (2227) is provided at the bottom of the outer cap (222). The outer cap shoulder (2227) is inserted into the top of the metal can (12) for connecting with the top of the metal can (12) in cooperation. An outer cap shoulder sealing groove (2228) is provided on the outer side of the outer cap shoulder (2227). An outer cap shoulder sealing ring (2229) is placed in the outer cap shoulder sealing groove (2228) to achieve radial sealing with the metal can (12); A plurality of outer cap snap fixing heads (2230) are circumferentially arranged on the outer side of the outer cap (222) for connecting with a plurality of fixing snap devices (124) on the metal can (12).

9. The device for realizing cryo-fixation of samples in supercooled liquid nitrogen according to claim 1, characterized in that, The sample delivery rod (3) includes a rod body (31), a fixing head (32), a limit bolt (33) and a handle (34). The handle (34) is installed at the top of the rod body (31). An insertion hole (312) penetrating the rod body (31) is provided at a position 20 - 30 mm away from the bottom of the rod body (31) for inserting the limit bolt (33). A sample delivery rod screw hole (311) is provided at the bottom of the rod body (31). The fixing head (32) is a detachable spindle-shaped metal block and is fixed in the sample delivery rod screw hole (311) by a screw. The rod body (31) is a metal round rod, and the limit bolt (33) is a metal cylinder with a pull ring at the top.

10. A device for freeze - fixing a sample in super - cooled liquid nitrogen as claimed in claim 9, wherein, The main body of the sample holder bracket (4) is a cubic metal base. Rectangular sheet-like protrusions (41) protruding laterally are provided on both sides of the sample holder bracket (4). Square sample table grooves (411) are formed on the protrusions (41) for placing the nail-leg sample table (44). A sample table groove insertion hole (412) is formed at the center of the sample table groove (411). A cubic fixing head slot (42) hollowed out laterally is provided at the rectangular top of the sample holder bracket (4) for placing the sample delivery rod fixing head (32) of the sample delivery rod (3). The upper surface of the fixing head slot (42) is not completely sealed and is provided with a fixing head socket (43) for inserting the sample delivery rod fixing head (32). A screw is inserted through the center of the bottom of the sample holder bracket (4), and the screw is inserted into the sample delivery rod fixing head (32) and the sample delivery rod screw hole (311) to realize the fixed connection of the sample holder bracket (4), the sample delivery rod fixing head (32) and the rod body (31).

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