Sample transfer bracket for cryoelectron microscope

Abstract

The utility model relates to the technical field of electron microscopes, and aims to solve the problems that a kettle-type Dewar tank on an existing transfer support is small in capacity, short in low-temperature maintaining time and short in electron microscope observation time, fluid in the Dewar tank is unevenly distributed during inclined observation, so that mechanical stress is increased, the position of a sample groove is vibrated, the tomography drift rate is increased, and the scanning time is shortened. The sample transfer support for the cryoelectron microscope comprises a support body, a Dewar tank is installed on the support body, the Dewar tank is of a cylinder structure, and the center line of the Dewar tank is along the X axis; the Dewar tank comprises a shell and an inner container, and a vacuum layer is arranged between the inner container and the shell. The support body comprises an outer rod. A heat conduction pipe is arranged in the outer rod; a sample groove is formed in the sample carrier, a sample protection cover is arranged on the sample groove, a pull rod is arranged in the heat conduction pipe, the front end of the pull rod is connected with the sample protection cover, the rear end of the pull rod is used for being connected with a control knob, and the control knob can drive the pull rod to axially move so as to open and close the sample protection cover.

Description

Technical Field

[0001] The utility model relates to the technical field of electron microscopes, and in particular to a sample transfer bracket for a cryo-electron microscope. Background Art

[0002] Cryo-electron microscopy is used to study biological and inorganic samples at low temperatures, preserving their natural state and providing high-resolution imaging capabilities. Before observation with the microscope, the sample needs to be transferred from the preparation stage to the electron microscope by a cryogenic transfer stand without affecting its cryogenic conditions. The transfer stand is usually equipped with a dewar, a special container that maintains the low temperatures required for cryo-electron microscopy.

[0003] However, the liquid nitrogen capacity of the Dewar tank on the traditional transfer stand is relatively small, about 150 mL, and the low temperature maintenance time is relatively short, about 3-4 hours, and the electron microscope observation time is short; the inclination angle of the traditional transfer stand is small, about ±40°, and the electron microscope observation range is small; the Dewar tank on the traditional transfer stand is a vertical Dewar tank (such as Figure 1 As shown, the Dewar tank adopts a pot-type structure, that is, it is a cylindrical structure along the Y axis, and the center of the Dewar tank is perpendicular to the X axis). When observed at an angle, the volume of liquid nitrogen in the Dewar tank is unevenly distributed along the left and right of the x-axis, which will increase the mechanical stress on the sample rod, and finally manifest as vibration or movement of the sample slot position, increase the drift rate during tomography, and make the scanned image unclear, affecting the clarity of the scanned image. Utility Model Content

[0004] The utility model aims to provide a sample transfer stand for a cryo-electron microscope, so as to solve the problems that the pot-type Dewar tank on the existing transfer stand has a small capacity, a short low-temperature maintenance time, a short electron microscope observation time, and when observing at an angle, the fluid in the Dewar tank is unevenly distributed, which leads to increased mechanical stress of the transfer stand, causing the position of the sample slot to vibrate or move, increasing the drift rate during tomographic scanning, and affecting the clarity of the scanned image.

[0005] The utility model is realized by adopting the following technical solutions:

[0006] The utility model provides a sample transfer support for a cryo-electron microscope, comprising a support body, a dewar tank is installed on the support body, the dewar tank adopts a cylindrical structure, and the center line of the dewar tank is along the X-axis;

[0007] The Dewar tank comprises an outer shell and an inner liner, wherein the inner liner is located inside the outer shell, liquid nitrogen is filled inside the inner liner, and a vacuum layer is formed between the inner liner and the outer shell;

[0008] The support body includes an outer rod, the outer rod is connected to one side of the outer shell, and the interior of the outer rod is connected to the interior of the outer shell;

[0009] A heat conducting pipe is arranged inside the outer rod, the rear end of the heat conducting pipe is used to be connected to the inner tank, and the front end of the heat conducting pipe is used to be connected to the sample carrier, so as to transfer the cold energy to the sample;

[0010] The sample carrier is provided with a sample slot, and a sample protection cover is provided on the sample slot. A pull rod is provided in the heat conduction tube, and the front end of the pull rod is connected to the sample protection cover, and the rear end of the pull rod is used to connect with the control knob, and the control knob can drive the pull rod to move axially to open and close the sample protection cover.

[0011] As the preferred technical solution:

[0012] A hollow channel is provided at the center of the inner tank, and the center line of the channel is also along the X-axis. A heat conducting plate is connected to one side of the inner tank, and the rear end of the heat conducting pipe passes through the channel and is connected to the heat conducting plate.

[0013] As the preferred technical solution:

[0014] The control knob is connected to the other side of the housing, and the control knob can move forward or backward relative to the housing.

[0015] As the preferred technical solution:

[0016] The control knob is connected to the housing via threads.

[0017] As the preferred technical solution:

[0018] The sample carrier is provided with a sliding groove, a sliding column is installed in the sliding groove, the sliding column can slide along the sliding groove, the sample protection cover is connected to the sliding column, and the front end of the pull rod is connected to the sliding column.

[0019] As the preferred technical solution:

[0020] The sliding column adopts a screw.

[0021] As the preferred technical solution:

[0022] A clutch structure is arranged between the rear end of the pull rod and the control knob, and the clutch structure is used to establish a connection between the pull rod and the control knob or to separate the two.

[0023] As the preferred technical solution:

[0024] The clutch structure includes flange one, a bellows, flange two, a ball head rod and a control rod. The rear end of the pull rod is connected to the tail of the ball head rod, and the ball head of the ball head rod can be inserted into the tail of the control rod. Flange one is installed on the outside of the ball head rod and connected to the inner side of the outer shell. Flange two is installed on the front end of the control rod. The bellows is sleeved on the outside of the ball head rod and the control rod. The two ends of the bellows are respectively abutted against flange one and flange two. The control knob is connected to flange two and can rotate around flange two.

[0025] As the preferred technical solution:

[0026] An O-ring is arranged in the tail of the control rod. When the ball head of the ball head rod is inserted into the tail of the control rod, the O-ring is sleeved on the outside of the ball head rod.

[0027] As the preferred technical solution:

[0028] A liquid nitrogen filling port is arranged on the top of the dewar tank.

[0029] As the preferred technical solution:

[0030] A positioning flange is arranged between the outer rod and the outer shell.

[0031] As the preferred technical solution:

[0032] A vacuum cable connector and a vacuum valve are installed on the other side of the shell. The vacuum cable connector is connected to the equipment control line, and the vacuum valve is connected to the vacuum pump.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

[0034] 1. The dewar tank on the transfer bracket of the utility model adopts a cylindrical structure, and the center line of the dewar tank is along the X-axis. When the dewar tank is tilted, the liquid nitrogen in the dewar tank is always evenly distributed on the left and right sides along the X-axis. The center of mass of the liquid nitrogen in the dewar tank is always on the X-axis, which will not cause the mechanical stress of the transfer bracket to increase, reduce the drift rate during tomography, and ensure the clarity of the scanned image. The dewar tank with a cylindrical structure increases the tilt angle of sample observation, with a maximum of ±80°; and the liquid nitrogen capacity of the dewar tank with a cylindrical structure is also relatively increased, which prolongs the low temperature time of the sample, and the sample observation time is also extended to 8-9 hours.

[0035] 2. The heat conduction pipe of the utility model is located inside the outer rod. Since the outer rod is connected to the vacuum layer, the inside of the outer rod is also a vacuum environment. Therefore, the heat conduction pipe is located in a vacuum environment and the pull rod is located in the heat conduction pipe, which cuts off the solid heat transfer generated by the movement of the pull rod, reduces heat, and prolongs the observation time.

[0036] 3. The inner center of the Dewar jar of the utility model is provided with a hollow channel, and the heat pipe is arranged through the channel to prevent the vibration caused by the boiling of liquid nitrogen in the Dewar jar from being directly transmitted to the heat pipe, thereby reducing the drift rate of the sample and ensuring the clarity of the image.

[0037] 4. The utility model connects or disconnects the pull rod and the control knob through the clutch structure, thereby adjusting the position of the sample protection cover so that the sample can be sealed during the transfer process to prevent other external factors from affecting the sample quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the structure of a traditional transfer bracket.

[0039] Figure 2 This is a schematic structural diagram of the sample transfer bracket for cryo-electron microscopy described in the present invention.

[0040] Figure 3 This is a schematic diagram of the sample transfer bracket for cryo-electron microscopy described in the present invention being installed on a sample loading platform.

[0041] Figure 4 This is a half-section view of the sample transfer stand for cryo-electron microscopy described in the present invention.

[0042] Figure 5 for Figure 4 Enlarged schematic diagram of point I in the middle.

[0043] Figure 6 This is a schematic diagram of the sample protection cover of the present invention being closed.

[0044] Figure 7 This is a top view of the sample transfer stand for cryo-electron microscopy described in the present invention.

[0045] Figure 8 for Figure 7 Cross-section view along the AA direction.

[0046] Fig. 9 for Figure 8 Enlarged schematic diagram of point II in the middle.

[0047] Fig.10 It is a schematic diagram of the connection between the control rod and the ball head rod described in the utility model.

[0048] Icons: 1-Dewar tank, 2-liquid nitrogen filling port, 3-outer rod, 4-control knob, 5-sample carrier, 6-sample loading platform, 7-outer shell, 8-inner liner, 9-vacuum layer, 10-heat pipe, 11-positioning flange, 12-liquid nitrogen, 13-heat conductive sheet, 14-vacuum cable connector, 15-vacuum valve, 16-pull rod, 17-sample slot, 18-sample protection cover, 19-screw, 20-stud, 21-flange one, 22-bellows, 23-flange two, 24-ball head rod, 25-control rod, 26-O-ring, 27-retaining ring. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0050] Example 1

[0051] like Figure 2-Figure 10 As shown, this embodiment proposes a sample transfer stand for a cryo-electron microscope, including a stand body, on which a Dewar tank 1 is installed, the Dewar tank 1 adopts a cylindrical structure, the center line of the Dewar tank 1 is along the X-axis, and the center line of the Dewar tank 1 coincides with the center line of the stand body. With the above structure, the liquid nitrogen 12 in the Dewar tank 1 is always evenly distributed on the left and right sides along the X-axis, and the center of mass of the liquid nitrogen 12 in the Dewar tank 1 is always on the X-axis. Compared with the existing pot-type Dewar tank, the utility model can reduce the drift rate during tomography and ensure that the scanned image is clear. Moreover, the capacity of the liquid nitrogen 12 of the cylindrical Dewar tank 1 is relatively increased, which prolongs the low-temperature time of the sample, and the sample observation time is also extended to 8-9 hours.

[0052] The top of the dewar tank 1 is provided with a liquid nitrogen filling port 2 for easy filling of liquid nitrogen 12 .

[0053] The Dewar tank 1 includes an outer shell 7 and an inner liner 8, wherein the inner liner 8 is located inside the outer shell 7, and liquid nitrogen 12 is filled inside the inner liner 8. A vacuum layer 9 is formed between the inner liner 8 and the outer shell 7 to reduce cold exchange with the environment.

[0054] The bracket body includes an outer rod 3 , which is connected to one side of the outer shell 7 . The interior of the outer rod 3 is communicated with the interior of the outer shell 7 . A positioning flange 11 is provided between the outer rod 3 and the outer shell 7 .

[0055] A vacuum cable connector 14 and a vacuum valve 15 are installed on the other side of the housing 7. The vacuum cable connector 14 is sealed by an O-ring and connected to the equipment control line to monitor the temperature of the sample slot end in real time. The vacuum valve 15 is connected to a vacuum pump to supplement the air inside the transfer bracket to maintain a good vacuum degree.

[0056] The center of the inner liner 8 is provided with a hollow tubular channel, the center line of which is also along the X-axis, the inner liner 8 is connected to a heat conducting sheet 13 on one side close to the vacuum valve 15, a heat conducting pipe 10 is provided inside the outer rod 3, the front end of the heat conducting pipe 10 is used to connect to the sample carrier 5, the rear end of the heat conducting pipe 10 passes through the channel and the heat conducting sheet 13, and is fixedly connected to the heat conducting sheet 13, the heat conducting pipe 10 is used to transfer the cold energy transferred from the inner liner 8 to the heat conducting sheet 13 to the sample carrier 5, so as to keep the sample at a low temperature. The vacuum layer 9 is connected to the space between the outer rod 3 and the heat conducting pipe 10.

[0057] The sample carrier 5 is provided with a sample slot 17, and the sample slot 17 is covered with a sample protection cover 18. The sample protection cover 18 is used to protect the sample from contamination, and the sample protection cover 18 can slide axially along the sample carrier 5. Specifically, a sliding slot is provided on the sample carrier 5, and a screw 19 is installed in the sliding slot. The outer sleeve of the screw 19 is provided with a stud 20, and the sample protection cover 18 is connected to the screw 19. Therefore, the sample protection cover 18 can move axially along the sliding slot as the screw 19 slides in the sliding slot to realize opening and closing. When the sample is transferred from the sample loading platform 6 to the electron microscope cavity, the sample protection cover 18 can be closed to prevent the low-temperature sample from contacting with moisture in the air and affecting the sample quality. After the transfer bracket is inserted into the electron microscope cavity, the sample protection cover 18 is opened.

[0058] A pull rod 16 is disposed inside the heat conducting pipe 10 . The rear end of the pull rod 16 extends out of the heat conducting pipe 10 and is used to connect to the control knob 4 . The front end of the pull rod 16 is connected to the screw 19 .

[0059] A clutch structure is provided between the rear end of the pull rod 16 and the control knob 4 , and the clutch structure is used to establish a connection between the pull rod 16 and the control knob 4 or to separate the two.

[0060] The clutch structure includes a flange 1 21, a bellows 22, a flange 23, a ball head rod 24 and a control rod 25. The rear end of the pull rod 16 is inserted into the tail of the ball head rod 24, and the two are fixedly connected; the ball head of the ball head rod 24 can be inserted into the tail of the control rod 25, and an O-ring 26 is arranged in the tail of the control rod 25. When the ball head of the ball head rod 24 is inserted into the tail of the control rod 25, the O-ring 26 is sleeved on the outside of the ball head rod 24; the flange 1 21 is installed on the outside of the ball head rod 24 and is connected to the housing. 7; the flange 23 is installed at the front end of the control rod 25, and the flange 23 is fixedly connected to the control rod 25; the bellows 22 is sleeved on the outside of the ball head rod 24 and the control rod 25, and the two ends of the bellows 22 are respectively abutted against the flange 1 21 and the flange 23; the control knob 4 is connected to the flange 23, and the control knob 4 can rotate around the flange 23, and a retaining ring 27 is provided between the control knob 4 and the flange 23; the control knob 4 is connected to the housing 7 by threads.

[0061] When the control knob 4 is turned clockwise, the control knob 4 moves forward relative to the housing 7, and the control knob 4 drives the flange 23 and the control rod 25 to move forward together. At this time, the bellows 22 is in a compressed state, and the control rod 25 is combined with the ball head rod 24, and drives the ball head rod 24 and the pull rod 16 to move forward together. At this time, the sample protection cover 18 at the front end of the transfer bracket is closed. Figure 6 and Fig.10 On the contrary, if the control knob 4 is rotated counterclockwise, the control knob 4 moves backward relative to the housing 7, and the control knob 4 drives the flange 23 and the control rod 25 to move backward together. At this time, the bellows 22 is in an extended state, and the control rod 25 drives the ball rod 24 to move backward together through the O-ring 26, thereby driving the pull rod 16 to move backward, thereby opening the sample protection cover 18. When the sample protection cover 18 is fully opened, as shown in FIG. Figure 5 As shown, the control knob 4 is continuously rotated, and the ball head rod 24 is disconnected from the control rod 25. Fig. 9 As shown, the clutch function is realized.

[0062] The interior of the bellows 22 is connected to the vacuum chamber of the Dewar 1 as a whole. This structure can ensure that the vacuum does not leak. When observing the sample, it can cut off the solid heat transfer caused by the pull rod 16, reduce the heat leakage of the system, and extend the observation time. At the same time, it can also reduce the vibration caused by factors such as the boiling of liquid nitrogen 12 in the Dewar 1, and transmit it to the sample slot 17 through the outer shell 7, thereby reducing the drift rate of the sample and ensuring the clarity of the image.

[0063] The utility model can reduce the consumption of liquid nitrogen 12, increase the low temperature keeping time of the sample, and prolong the observation time of the electron microscope; increase the tilt angle of sample observation, with a maximum of ±80°; the liquid nitrogen is evenly distributed on the left and right sides of the X-axis in the Dewar tank 1, the transfer bracket is more stable, the drift rate of the sample is limited, and the image observation is clearer.

[0064] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A sample transfer stand for cryo-electron microscopy, characterized in that: It includes a support body, on which a Dewar tank is installed, the Dewar tank adopts a cylindrical structure, and the center line of the Dewar tank is along the X-axis; The Dewar tank comprises an outer shell and an inner liner, wherein the inner liner is located inside the outer shell, liquid nitrogen is filled inside the inner liner, and a vacuum layer is formed between the inner liner and the outer shell; The support body includes an outer rod, the outer rod is connected to one side of the outer shell, and the interior of the outer rod is connected to the interior of the outer shell; A heat conducting pipe is arranged inside the outer rod, the rear end of the heat conducting pipe is used to be connected to the inner tank, and the front end of the heat conducting pipe is used to be connected to the sample carrier, so as to transfer the cold energy to the sample; The sample carrier is provided with a sample slot, and a sample protection cover is provided on the sample slot. A pull rod is provided in the heat conduction tube, and the front end of the pull rod is connected to the sample protection cover, and the rear end of the pull rod is used to connect with the control knob, and the control knob can drive the pull rod to move axially to open and close the sample protection cover.

2. The sample transfer stand for cryo-electron microscopy according to claim 1, characterized in that: A hollow channel is provided at the center of the inner tank, and the center line of the channel is also along the X-axis. A heat conducting plate is connected to one side of the inner tank, and the rear end of the heat conducting pipe passes through the channel and is connected to the heat conducting plate.

3. The sample transfer stand for cryo-electron microscopy according to claim 1, characterized in that: The control knob is connected to the other side of the housing, and the control knob can move forward or backward relative to the housing.

4. The sample transfer stand for cryo-electron microscopy according to claim 3, characterized in that: The control knob is connected to the housing via threads.

5. The sample transfer stand for cryo-electron microscopy according to claim 1, characterized in that: The sample carrier is provided with a sliding groove, a sliding column is installed in the sliding groove, the sliding column can slide along the sliding groove, the sample protection cover is connected to the sliding column, and the front end of the pull rod is connected to the sliding column.

6. The sample transfer stand for cryo-electron microscopy according to claim 1, characterized in that: A clutch structure is arranged between the rear end of the pull rod and the control knob, and the clutch structure is used to establish a connection between the pull rod and the control knob or to separate the two.

7. The sample transfer stand for cryo-electron microscopy according to claim 6, characterized in that: The clutch structure includes flange one, a bellows, flange two, a ball head rod and a control rod. The rear end of the pull rod is connected to the tail of the ball head rod, and the ball head of the ball head rod can be inserted into the tail of the control rod. Flange one is installed on the outside of the ball head rod and connected to the inner side of the outer shell. Flange two is installed on the front end of the control rod. The bellows is sleeved on the outside of the ball head rod and the control rod. The two ends of the bellows are respectively abutted against flange one and flange two. The control knob is connected to flange two and can rotate around flange two.

8. The sample transfer stand for cryo-electron microscopy according to claim 7, characterized in that: An O-ring is arranged in the tail of the control rod. When the ball head of the ball head rod is inserted into the tail of the control rod, the O-ring is sleeved on the outside of the ball head rod.

9. The sample transfer stand for cryo-electron microscopy according to claim 1, characterized in that: A liquid nitrogen filling port is arranged on the top of the dewar tank.

10. The sample transfer stand for cryo-electron microscopy according to claim 1, characterized in that: A vacuum cable connector and a vacuum valve are installed on the other side of the shell. The vacuum cable connector is connected to the equipment control line, and the vacuum valve is connected to the vacuum pump.

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