Centrifugal tube convenient to clean and used for ultra-speed centrifugal machine

Abstract

The invention provides a centrifuge tube convenient to clean for an ultra-speed centrifuge, and relates to the technical field of centrifuge tubes. A PVDF coating is sprayed on the inner wall of the centrifugal tube; the preparation method comprises the following steps: S1, preparing a centrifugal tube in a blow molding manner; s2, after the centrifugal tube is formed, a PVDF mixed solution is sprayed in the mold; s3, cooling and drying; the preparation of the centrifuge tube convenient to clean for the ultra-speed centrifuge is realized through the steps. By means of the steps, the anti-corrosion coating can be arranged in the centrifugal tube almost without damage, due to the fact that spraying processing is conducted after blow molding, the anti-corrosion coating is high in adhesive force and not prone to falling off in the using process, the service life of the centrifugal tube for the ultra-high-speed centrifugal machine is prolonged, and the centrifugal tube can be conveniently cleaned under the condition that economical efficiency is permitted.

Description

Technical Field

[0001] The invention relates to the technical field of centrifuge tubes, in particular to a centrifuge tube for an ultracentrifuge which is easy to clean. Background Art

[0002] In the virus separation operation, an ultra-high-speed centrifuge is required to separate the virus at a maximum speed of 100,000 revolutions. The centrifuge tube needs to withstand a large gravitational acceleration, so the centrifuge tube needs to ensure sufficient strength to avoid breaking during the centrifugal operation. The existing centrifuge tubes used for the above working conditions are expensive and can only be used once, resulting in high experimental costs. The centrifuge tubes need to be cleaned when reused, because steam, boiling and ultraviolet light cleaning will damage the centrifuge tubes, and such damage is difficult to avoid during the cleaning process. A better cleaning method is alcohol cleaning, but alcohol is a better solvent and will also cause certain damage to the centrifuge tube, affecting the service life of the centrifuge tube. In the prior art, there are also solutions for setting a coating to isolate solvent damage, such as using PVDF coating, that is, polyvinylidene fluoride (Polyvinylidene Fluoride) coating, which has excellent resistance to most acids, alkalis, salts and solvents. However, the coating has weak adhesion, and the sprayed surface needs to be roughened during spraying. If the centrifuge tube is roughened, fine cracks will be left on the surface of the centrifuge tube. These cracks will become the basis for crack development under the conditions of high-speed rotation and high gravitational acceleration, thereby causing the centrifuge tube to break. Therefore, it is a technical problem of the prior art to set a coating on the surface of a high-strength centrifuge tube. It should be noted that this preparation scheme also needs to be within the scope of economic efficiency. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a centrifuge tube for an ultracentrifuge that is easy to clean, and an anti-corrosion coating can be conveniently provided on the inner wall of the centrifuge tube, so that the centrifuge tube can be conveniently cleaned under economic conditions. In a preferred solution, it is possible to easily detect whether the strength of the centrifuge tube meets the use requirements.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a centrifuge tube for ultracentrifuge that is easy to clean, the inner wall of the centrifuge tube is sprayed with PVDF coating; The preparation method comprises the following steps: S1. preparing a centrifuge tube by blow molding; S2, spraying PVDF mixed solution in the mold after the centrifugal tube is formed; S3, cooling and drying; The above steps are used to prepare a centrifuge tube for an ultracentrifuge that is easy to clean.

[0005] In a preferred embodiment, in step S1, the centrifuge tube is made of PC; PC particles are pre-dried at 120°C ± 5°C for 4-8h; During blow molding, the material temperature is 300°C ± 10°C and the mold temperature is 80°C to 95°C.

[0006] In a preferred embodiment, in step S2, PVDF and one of NMP, DMAc or DMF are prepared into a mixed solution; Spray the PVDF mixed solution on the inner wall of the centrifuge tube being formed in the mold by rotating from top to bottom and then from top to bottom 1 to 3 times.

[0007] In a preferred embodiment, in step S2, at room temperature, the ratio of PVDF to NMP is 10-50% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMAc is 10 to 30% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMF is 10-30% of the total weight of PVDF; The spraying time is when the centrifuge tube being formed is cooled to below 85°C and then spraying is started.

[0008] In a preferred solution, a spray tube is provided on the blow molding head of the mold, and the spray tube slides up and down along the axis of the centrifugal tube and rotates along the axis; A plurality of spray heads are arranged at the bottom of the spray pipe, a valve stem is arranged at the center position of the spray pipe, and a valve head is arranged at the bottom end of the valve stem. When the spray pipe reaches the upper limit position, the valve head blocks the passage of the spray pipe. When the spray pipe leaves the upper limit position, the valve head opens the passage of the spray pipe.

[0009] In a preferred solution, the spraying pipe is connected to the slurry inlet pipe through a rotary joint, a servo motor is fixed on the rotary joint, the servo motor contacts the spraying pipe through a friction wheel, and drives the spraying pipe to rotate; The valve stem is fixedly connected to the frame, and the frame is connected to the rotary joint through an electric push rod. The electric push rod is parallel to the axis of the valve stem to push the rotary joint to reciprocate up and down.

[0010] In a preferred embodiment, S4 also includes a testing step to test whether the strength of the centrifuge tube meets the strength requirements; The specific steps include: S41, pressurizing the centrifuge tube and filling it with medium; S42, pressurizing the centrifuge tube to 75% to 95% of the yield pressure of the centrifuge tube and filling the medium; S43, online monitoring of the diameter deformation of the centrifuge tube; S44. Select the centrifuge tube that has returned to its original diameter as qualified.

[0011] In a preferred embodiment, the device for testing the strength of the centrifuge tube adopts the following structure: It includes a plunger, a conduit is arranged inside the plunger, and the plunger is used to form a sealing structure with the bottle mouth of the centrifuge tube; The conduit is connected to the output port of the pressure medium source; A pressure sensor is provided on the catheter; A diameter monitoring device is also provided, and the diameter monitoring device is used to detect the diameter change of the centrifuge tube.

[0012] In a preferred solution, the plunger is fixed on the bottom plate, bolts are fixed on the bottom plate, and a gland is provided. The gland is provided with holes corresponding to the bolts, and the bolts pass through the holes and are connected with nuts. The centrifuge tube is used to be arranged between the bottom plate and the gland, and the mouth of the centrifuge tube is sleeved on the plunger, and a sealing ring is provided on the outer wall of the plunger; A limiting ring is also fixedly arranged on the periphery of the plunger, and the limiting ring is located on the periphery of the centrifuge tube orifice to limit the deformation of the centrifuge tube orifice; The structure of the pressure medium source is: the outlet of the pump is connected to the inlet of the pressure regulating valve, the outlet of the pressure regulating valve is connected to the inlet of the control valve, and the outlet of the control valve is connected to the conduit; The circulation port of the pressure regulating valve is connected to the inlet of the pump through a circulation pipe; A buffer tank is also provided on the catheter, and a compressed air bag is provided in the buffer tank.

[0013] In a preferred solution, the structure of the diameter monitoring device is as follows: a detection belt is wound around the outer wall of the centrifuge tube, one end of the detection belt is fixed, and the other end is connected to a fixed displacement sensor to detect the change in the circumference of the centrifuge tube, and the diameter change of the centrifuge tube is calculated based on the change in the circumference; Displacement sensors include capacitive, grating or wound disc displacement sensors.

[0014] The invention provides a centrifuge tube for an ultracentrifuge that is easy to clean and has the following beneficial effects: 1. The method of the present invention can provide an anti-corrosion coating in a centrifuge tube almost without damage, and because the spraying process is performed immediately after blow molding, the anti-corrosion coating has high adhesion and is not easy to fall off during use, thereby extending the service life of the centrifuge tube used for the ultra-high-speed centrifuge.

[0015] 2. The improved mold of the present invention can be sprayed after blow molding, which is very convenient to operate and can form a coating with uniform thickness.

[0016] 3. The inspection device of the present invention ensures that the centrifuge tube used can meet the use requirements by monitoring the diameter deformation under pressure, thereby avoiding the centrifuge tube damage under ultra-high-speed conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 is a flow chart of the method for preparing a centrifuge tube of the present invention; Figure 2 It is a flow chart of the centrifuge tube inspection method of the present invention; Figure 3 It is a structural schematic diagram of a mold for preparing a centrifuge tube of the present invention; Figure 4 It is a partial enlarged schematic diagram of the spray pipe in the present invention; Figure 5 It is a structural schematic diagram of the detection device of the present invention; Figure 6 It is a structural schematic diagram of the capacitive diameter monitoring device of the present invention; Figure 7 It is a structural schematic diagram of the grating type diameter monitoring device of the present invention; Figure 8 It is a structural schematic diagram of the winding disc diameter monitoring device of the present invention; Fig. 9 It is a schematic structural diagram of the pressure medium source of the present invention.

[0018] In the figure: gland 1; bolt 2; centrifuge tube 3; plunger 4; sealing ring 5; catheter 6; pressure medium source 7; circulation pipe 71; pump 72; pressure regulating valve 73; buffer tank 74; compressed air bag 75; pressure sensor 8; control valve group 9; displacement sensor 10; first electrode layer 101; second electrode layer 102; damper 103; insulation section 104; electrode medium section 105; fixed connector 106; metal detection belt 1 07; grating head 108; grating guide rail 109; angle sensor 110; winding disk 111; detection belt 11; exhaust valve 12; bottom plate 13; outer mold 14; centrifuge tube in molding 15; blow molding head 16; injection cavity 161; air pipe 162; spray pipe 17; rotary joint 18; valve stem 19; valve head 20; nozzle 21; slurry inlet pipe 22; air pipe 23; electric push rod 24; servo motor 25; limit ring 26. DETAILED DESCRIPTION

[0019] like Figure 1-9 As shown, a centrifuge tube for ultracentrifuge that is easy to clean, the inner wall of the centrifuge tube 3 is sprayed with PVDF coating; The preparation method comprises the following steps: S1, preparing a centrifuge tube 3 by blow molding; S2, after the centrifuge tube 3 is formed, the PVDF mixed solution is sprayed in the mold; S3, cooling and drying; The above steps are used to prepare a centrifuge tube for an ultracentrifuge that is easy to clean.

[0020] like Figure 1 As shown, this embodiment prepares a centrifuge tube for ultracentrifuge that meets the requirements and is easy to clean by blow molding, spraying PVDF mixed solution, cooling and drying. Reasonable material selection, process control and quality inspection are carried out during the preparation process to ensure that the performance and quality of the centrifuge tube reach the best state. The following is a detailed description of each step: In step S1 , a medium is charged into a new centrifuge tube 3 under pressure, and the diameter deformation of the centrifuge tube 3 is detected online.

[0021] The centrifuge tube 3 in this example is made of PVC or PC. In a preferred embodiment, the medium filled is air or water. In an optional embodiment, water is used as the medium filled in the centrifuge tube 3 made of PVC material, and compressed air is used as the medium in the centrifuge tube 3 made of PC material.

[0022] PVC polyvinyl chloride is a thermoplastic plastic, which is divided into two categories: soft PVC and hard PVC. In this case, hard PVC is used. PC polycarbonate is an engineering plastic with high strength and toughness.

[0023] In a preferred embodiment, in step S1, the material of the centrifuge tube 3 is PC; PC particles are pre-dried at 120°C ± 5°C for 4-8h; During blow molding, the material temperature is 300°C ± 10°C and the mold temperature is 80°C to 95°C.

[0024] In this embodiment, by setting a reasonable temperature and pre-drying time, the moisture in the PC particles is fully removed, and the potential impact of bubbles generated during the process is eliminated, thereby improving the product quality. The mold temperature ensures that the strength and internal stress of the PC are evenly distributed during the blow molding process.

[0025] In a preferred embodiment, in step S2, PVDF (polyvinylidene fluoride) and one of NMP (N-methylpyrrolidone), DMAc (dimethylacetamide) or DMF (dimethylformamide) are prepared into a mixed solution; The PVDF mixed solution is sprayed on the inner wall of the centrifuge tube 15 being formed in the mold by rotating and spraying from top to bottom and then from top to bottom for 1 to 3 times.

[0026] In a preferred embodiment, in step S2, at room temperature, the ratio of PVDF to NMP is 10-50% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMAc is 10 to 30% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMF is 10-30% of the total weight of PVDF; The spraying time is when the centrifuge tube 15 being formed is cooled to below 85° C. and then spraying is started.

[0027] Embodiment 2: Further illustrate with reference to Example 1, Figure 3-4 As shown, a device suitable for the method of Example 1 is shown.

[0028] In a preferred embodiment, a spraying tube 17 is provided on the blow molding head 16 of the mold, and the spraying tube 17 slides up and down along the axis direction of the centrifugal tube 3 and rotates along the axis; A plurality of spray heads 21 are provided at the bottom of the spray tube 17, a valve stem 19 is provided at the center position of the spray tube 17, and a valve head 20 is provided at the bottom end of the valve stem 19. When the spray tube 17 reaches the upper limit position, the valve head 20 blocks the passage of the spray tube 17. When the spray tube 17 leaves the upper limit position, the valve head 20 opens the passage of the spray tube 17.

[0029] This embodiment realizes all-round spraying of the inner wall of the centrifuge tube 3 by sliding up and down and rotating the spray tube 17, without manually adjusting the spray position, thereby improving the spraying efficiency, ensuring the uniformity of the spraying, and avoiding the problem of slurry hanging on the wall. A valve stem 19 and a valve head 20 are provided at the center of the spray tube 17 to improve the control accuracy of the spraying process: when the spray tube 17 reaches the upper limit position, the valve head 20 blocks the channel of the spray tube 17 to prevent the solution from continuing to flow out; when the spray tube 17 leaves the upper limit position, the valve head 20 opens the channel to allow the solution to flow out for spraying. Due to this structure, the spraying process is not affected by the distance between the valve and the nozzle, and can be quickly cut off to avoid delays. This is an important guarantee to ensure the uniformity of the spraying.

[0030] In a preferred embodiment, the spraying pipe 17 is connected to the slurry inlet pipe 22 via a rotary joint 18, and a servo motor 25 is fixedly mounted on the rotary joint 18. The servo motor 25 contacts the spraying pipe 17 via a friction wheel and drives the spraying pipe 17 to rotate. The valve stem 19 is fixedly connected to the frame, and the frame is connected to the rotary joint 18 through an electric push rod 24. The electric push rod 24 is parallel to the axis of the valve stem 19 to push the rotary joint 18 to reciprocate up and down.

[0031] In this embodiment, the servo motor 25 and the electric push rod 24 are controlled by PLC (Programmable Logic Controller) or DCS (Distributed Control System), realizing the precise control of the rotation speed, up and down sliding speed and position of the spray tube. The servo motor contacts the spray tube 17 through the friction wheel and drives it to rotate, which not only ensures the control accuracy, but also can transmit torque more flexibly and simplifies the transmission structure.

[0032] Embodiment 3: Further illustrate with reference to Example 1, Figure 2 As shown, a detailed inspection process for the strength of the centrifuge tube 3 is provided.

[0033] In a preferred solution, step S4 also includes an inspection step to inspect whether the strength of the centrifuge tube 3 meets the strength requirements to avoid damage in the ultra-high speed centrifuge.

[0034] The specific steps include: S41, pressurizing and filling the centrifuge tube 3 with the medium; S42, pressurizing the centrifuge tube to fill the medium at 75% to 95% of the yield pressure of the centrifuge tube 3; S43, online monitoring of the diameter deformation of the centrifuge tube 3; S44, select the centrifuge tube 3 that has returned to its initial diameter as qualified.

[0035] The strength test of the complete centrifuge tube is carried out through steps S41-S44. The initial diameter of the centrifuge tube 3 is first detected, and the medium is filled into the centrifuge tube until it reaches 75% to 95% of the yield pressure of the centrifuge tube, and the changes are monitored online. After reaching the predetermined pressure value and maintaining it for a period of time, the pressure is slowly released. Then the diameter of the centrifuge tube is measured again and compared with the initial diameter before pressurization: if the diameter change is within the allowable range, the centrifuge tube is considered to be qualified.

[0036] In a preferred embodiment, the device for testing the strength of the centrifuge tube 3 adopts the following structure: It includes a plunger 4, in which a conduit 6 is arranged, and the plunger 4 is used to form a sealing structure with the bottle mouth of the centrifuge tube 3; The conduit 6 is connected to the output port of the pressure medium source 7; A pressure sensor 8 is provided on the conduit 6; A diameter monitoring device is also provided, and the diameter monitoring device is used to detect the diameter change of the centrifuge tube 3.

[0037] like Figure 5 As shown, this embodiment is used to test the strength of the centrifuge tube to ensure that it can withstand a certain pressure. The pressure medium source 7 is a device that provides pressure medium, which can be an air pump, a water pump or other device that can provide stable pressure.

[0038] In the preferred embodiment, Figure 5 As shown, the plunger 4 is fixed on the bottom plate 13, the bolt 2 is also fixed on the bottom plate 13, and a gland 1 is also provided. The gland 1 is provided with a hole corresponding to the bolt 2, and the bolt 2 passes through the hole and is connected with a nut. The centrifuge tube 3 is used to be arranged between the bottom plate 13 and the gland 1, and the mouth of the centrifuge tube 3 is sleeved on the plunger 4, and a sealing ring 5 is provided on the outer wall of the plunger 4; like Figure 3 As shown, a limiting ring 26 is fixedly disposed on the periphery of the plunger 4. The limiting ring 26 is located on the periphery of the mouth of the centrifuge tube 3 and is used to limit the deformation of the mouth of the centrifuge tube 3. like Fig. 9 As shown, the structure of the pressure medium source 7 is: the outlet of the pump 72 is connected to the inlet of the pressure regulating valve 73, the outlet of the pressure regulating valve 73 is connected to the inlet of the control valve, and the outlet of the control valve is connected to the conduit 6; The circulation port of the pressure regulating valve 73 is connected to the inlet of the pump 72 through the circulation pipe 71; A buffer tank 74 is also provided on the catheter 6 , and a compression air bag 75 is provided in the buffer tank 74 .

[0039] In this embodiment, the control valve is located after the pressure regulating valve 73 and is used to control the on-off of the medium, so as to open or close the medium delivery as needed during the inspection process.

[0040] The use of the pressure medium source 7 is to set the circulation pressure of the pressure regulating valve 73. When the output pressure of the pump 72 is higher than the set pressure, the medium enters the inlet of the pump 72 through the circulation pipe 71. The buffer tank 74 is used to buffer the pressure fluctuation of the plunger pump. When in use, first set the circulation pressure of the pressure regulating valve 73, so that the pump 72 continues to supply the pressure medium to the buffer tank 74 at a preset pressure until the pressure reaches the preset value, turn off the pump 72, and maintain the pressure by the one-way valve at the outlet of the pump 72. Check whether the pressure of the pressure sensor 8 reaches the preset value. The pressure usually set will be higher than the pressure required for the experiment, because when the control valve is opened, a part of the pressure value will be lost. After opening the control valve, the experiment is completed, and the diameter of the centrifuge tube 3 is detected by the diameter monitoring device. Then the exhaust valve 12 is depressurized, and a new centrifuge tube 3 is reinstalled for detection.

[0041] In the preferred embodiment, Figure 5 As shown, the structure of the diameter monitoring device is as follows: a detection belt 11 is wound around the outer wall of the centrifuge tube 3, one end of the detection belt 11 is fixed, and the other end is connected to a fixed displacement sensor 10 to detect the change in the circumference of the centrifuge tube 3, and the change in the diameter of the centrifuge tube 3 is calculated according to the change in the circumference; The displacement sensor 10 includes a capacitive, grating or wound disk displacement sensor.

[0042] In this embodiment, the stroke diameter monitoring device uses a detection head to contact the outer wall of the centrifuge tube 3, measures the displacement of the detection head in a mechanical, electromagnetic or photoelectric manner, and calculates the diameter change of the centrifuge tube 3 based on the displacement of the detection head; taking a micrometer as an example, the detection end of the micrometer is contacted with the outer wall of the centrifuge tube 3, and the position of the micrometer at this time is set to zero. When the diameter of the centrifuge tube 3 changes, the displacement of the micrometer detection rod is used to obtain the value of the diameter change.

[0043] For some plastics, such as PC, the breaking pressure value of PC is relatively close to the yield pressure value, so it is necessary to accurately detect the diameter change. The circumference diameter monitoring device uses a detection tape 11 to be wound on the outer wall of the centrifuge tube 3. One end of the detection tape 11 is fixed, and the other end is connected to a fixed displacement sensor 10 to detect the circumference change of the centrifuge tube 3, and the diameter change of the centrifuge tube 3 is calculated based on the circumference change. With this structure, the detection accuracy is the highest, and the highest accuracy can reach nanometers. Thereby, accurate detection results are obtained to avoid excessive numerical differences in pressure, damage to the centrifuge tube 3, or allowing unqualified centrifuge tubes 3 to pass the test. Circumference change detection can be achieved in the following ways: 1) Capture an image of the centrifuge tube 3, and detect the diameter change of the centrifuge tube 3 based on the image; during the detection, a high-definition camera, such as a 4k camera, is used to capture the image of the middle position of the centrifuge tube 3. After calibration, the pixels of the image are corresponded to the diameter data, and the diameter of the centrifuge tube 3 is obtained based on the pixel data by identifying the edge of the centrifuge tube 3.

[0044] 2) Use the corresponding beam array to detect the diameter change of the centrifuge tube 3; the centrifuge tube is detected by multiple array beams. When the diameter of the centrifuge tube 3 changes, more beams are blocked. The position of the beam array is matched with the diameter data to obtain the diameter of the centrifuge tube 3.

[0045] 3) Use laser or sonar to detect the distance between the transmitter head and the outer wall of the centrifuge tube 3, and calculate the change in the diameter of the centrifuge tube 3 according to the change in distance; the transmitter head is fixed in position, and the transmitter head first emits laser or sonar, and calculates the distance between the transmitter head and the outer wall of the centrifuge tube 3 according to the flight time of the reflected light or reflected wave. According to the change in distance, the change in the diameter of the centrifuge tube 3 is calculated.

[0046] The displacement sensor 10 in this embodiment includes a capacitive, grating or winding disk displacement sensor, which is specifically described as follows: 1) The structure of the capacitive displacement sensor 10 is that the detection belt 11 passes between the first electrode layer 101 and the second electrode layer 102, and an insulating section 104 and an electrode dielectric section 105 are provided on the detection belt 11, wherein the lengths of the insulating section 104 and the electrode dielectric section 105 are equal, and the lengths of the insulating section 104 and the electrode dielectric section 105 are slightly larger than the range of deformation of the circumference of the centrifuge tube 3. For example, the length of the insulating section 104 and the electrode dielectric section 105: the range of deformation of the circumference of the centrifuge tube 3 is 1.2:1. A damper 103 is also provided to provide damping for the detection belt 11. By detecting the capacitance change between the first electrode layer 101 and the second electrode layer 102, the deformation value of the circumference of the centrifuge tube 3 can be obtained, and then the diameter change of the centrifuge tube 3 can be calculated.

[0047] 2) The structure of the grating displacement sensor 10 is that the grating guide 109 is fixedly arranged, the grating head 108 is slidably connected to the grating guide 109, the grating head 108 is fixedly connected to the detection belt 11, and the circumference deformation of the centrifuge tube 3 drives the grating head 108 to move, thereby obtaining the deformation value of the circumference of the centrifuge tube 3, and then calculating the diameter change of the centrifuge tube 3. The structure of the grating displacement detection is the existing technology.

[0048] 3) The structure of the winding disk displacement sensor is that the winding disk 111 is connected to the absolute value sensor 110 to drive the absolute value sensor 110 to rotate, thereby obtaining the rotation angle data of the winding disk 111. The detection belt 11 is wound on the winding disk 111. The position of the winding disk 111 when it is wound on the centrifuge tube 3 is assumed to be the initial position, that is, the zero position. During the experiment, the diameter deformation of the centrifuge tube 3 drives the detection belt 11 to move, thereby driving the winding disk 111 to rotate. The deformation value of the circumference of the centrifuge tube 3 is calculated from the rotation angle data of the absolute value sensor 110, and then the diameter change of the centrifuge tube 3 is calculated.

[0049] like Figure 6 As shown, in this embodiment, one end of the detection belt 11 is fixedly connected to the bolt 2 through a fixed connector 106. Preferably, the detection belt 11 is a metal belt, the fixed connector 106 is a hook with a magnet, and the displacement sensor 10 is fixedly connected to the current or another bolt; that is, the displacement sensor 10 can be fixed on the current bolt or on another bolt, and the fixing method is preferably a clamp fixing method. Although the detection belt 11 is spiral in the centrifuge tube 3, the length change of the detection belt 11 is linearly related to the diameter change. Therefore, the diameter change of the centrifuge tube 3 can be accurately calculated according to the length change of the detection belt 11.

[0050] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A centrifuge tube for an ultracentrifuge that is easy to clean, characterized in that: The inner wall of the centrifuge tube (3) is sprayed with a PVDF coating; The preparation method comprises the following steps S1, preparing a centrifuge tube (3) by blow molding; S2, after the centrifuge tube (3) is formed, a PVDF mixed solution is sprayed in the mold; S3, cooling and drying; The above steps are used to prepare a centrifuge tube for an ultracentrifuge that is easy to clean.

2. The ultracentrifuge tube easy to clean according to claim 1, characterized in that: In S1, the material of the centrifuge tube (3) is PC; PC particles are pre-dried at 120°C ± 5°C for 4-8h; During blow molding, the material temperature is 300°C ± 10°C and the mold temperature is 80°C to 95°C.

3. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 1 or 2, characterized in that: In step S2, PVDF and one of NMP, DMAc or DMF are prepared into a mixed solution; The PVDF mixed solution is sprayed on the inner wall of the centrifuge tube (15) being formed in the mold by rotating and spraying from top to bottom and then from top to bottom 1 to 3 times.

4. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 2, characterized in that In step S2, at room temperature, the ratio of PVDF to NMP is 10-50% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMAc is 10 to 30% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMF is 10-30% of the total weight of PVDF; The spraying time is when the centrifuge tube (15) being formed is cooled to below 85°C and then spraying is started.

5. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 3, characterized in that: The blow molding head (16) of the mold is provided with a spraying tube (17), and the spraying tube (17) slides up and down along the axis direction of the centrifugal tube (3) and rotates along the axis; A plurality of spray heads (21) are provided at the bottom of the spray pipe (17), a valve stem (19) is provided at the center of the spray pipe (17), and a valve head (20) is provided at the bottom end of the valve stem (19). When the spray pipe (17) reaches an upper limit position, the valve head (20) blocks the passage of the spray pipe (17), and when the spray pipe (17) leaves the upper limit position, the valve head (20) opens the passage of the spray pipe (17).

6. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 3, characterized in that: The spraying pipe (17) is connected to the slurry inlet pipe (22) via a rotary joint (18). A servo motor (25) is fixedly mounted on the rotary joint (18). The servo motor (25) contacts the spraying pipe (17) via a friction wheel and drives the spraying pipe (17) to rotate. The valve stem (19) is fixedly connected to the frame, and the frame is connected to the rotary joint (18) via an electric push rod (24). The electric push rod (24) is parallel to the axis of the valve stem (19) so as to push the rotary joint (18) to reciprocate up and down.

7. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 1, characterized in that: S4, further comprising a testing step to test whether the strength of the centrifuge tube (3) meets the strength requirements; The specific steps include: S41, pressurizing the centrifuge tube (3) and filling it with a medium; S42, pressurizing the centrifuge tube to 75% to 95% of the yield pressure of the centrifuge tube (3) and filling the medium; S43, online monitoring of the diameter deformation of the centrifuge tube (3); S44. The centrifuge tube (3) that has returned to its original diameter is selected as qualified.

8. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 7, characterized in that: The device for testing the strength of the centrifuge tube (3) adopts the following structure: It comprises a plunger (4), a conduit (6) is arranged inside the plunger (4), and the plunger (4) is used to form a sealing structure with the bottle mouth of the centrifuge tube (3); The conduit (6) is connected to the output port of the pressure medium source (7); A pressure sensor (8) is provided on the catheter (6); A diameter monitoring device is also provided, and the diameter monitoring device is used to detect the change in the diameter of the centrifuge tube (3).

9. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 8, characterized in that: The plunger (4) is fixed on the bottom plate (13), a bolt (2) is also fixed on the bottom plate (13), and a gland (1) is also provided. The gland (1) is provided with a hole corresponding to the bolt (2), and the bolt (2) passes through the hole and is connected to a nut. The centrifuge tube (3) is used to be arranged between the bottom plate (13) and the gland (1), and the mouth of the centrifuge tube (3) is sleeved on the plunger (4). A sealing ring (5) is provided on the outer wall of the plunger (4); A limiting ring (26) is also fixedly provided on the periphery of the plunger (4), and the limiting ring (26) is located on the periphery of the mouth of the centrifuge tube (3) and is used to limit deformation of the mouth of the centrifuge tube (3); The structure of the pressure medium source (7) is as follows: the outlet of the pump (72) is connected to the inlet of the pressure regulating valve (73), the outlet of the pressure regulating valve (73) is connected to the inlet of the control valve, and the outlet of the control valve is connected to the conduit (6); The circulation port of the pressure regulating valve (73) is connected to the inlet of the pump (72) through the circulation pipe (71); A buffer tank (74) is also provided on the catheter (6), and a compressed air bag (75) is provided in the buffer tank (74).

10. The centrifuge tube for ultracentrifuge that is easy to clean according to claim 8, characterized in that: The structure of the diameter monitoring device is as follows: a detection belt (11) is wound around the outer wall of the centrifuge tube (3), one end of the detection belt (11) is fixed, and the other end is connected to a fixed displacement sensor (10) to detect the change in the circumference of the centrifuge tube (3), and the change in the diameter of the centrifuge tube (3) is calculated based on the change in the circumference; The displacement sensor (10) comprises a capacitive, grating or winding disk displacement sensor.

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