Centrifuge tube for ultra-centrifuge easy to clean

Abstract

The application provides a centrifuge tube for an ultracentrifuge, which is convenient to clean and relates to the technical field of centrifuge tubes. The inner wall of the centrifuge tube is sprayed with a PVDF coating layer. The preparation method comprises the following steps: S1, preparing the centrifuge tube in a blow molding mode; S2, spraying a PVDF mixed solution in the mold after the centrifuge tube is formed; and S3, cooling and drying. The preparation of the centrifuge tube for the ultracentrifuge which is convenient to clean is realized through the above steps. Through the above steps, the anticorrosive coating layer can be arranged in the centrifuge tube almost without damage. Since the spraying processing is performed after blow molding, the adhesion of the anticorrosive coating layer is high, the anticorrosive coating layer is not easy to fall off in the use process, the service life of the centrifuge tube for the ultracentrifuge is prolonged, and the centrifuge tube can be conveniently cleaned under the condition that the economy is permitted.

Description

Technical Field

[0001] This invention relates to the field of centrifuge tube technology, and in particular to a centrifuge tube for an ultracentrifuge that is easy to clean. Background Technology

[0002] In virus isolation, ultra-high-speed centrifuges are required, operating at speeds up to 100,000 rpm to separate the viruses. Centrifuge tubes need to withstand significant gravitational acceleration, necessitating sufficient strength to prevent breakage during centrifugation. Existing centrifuge tubes for these conditions are expensive and can only be used once, leading to high experimental costs. Reusing the tubes requires cleaning, as steam, boiling, and UV cleaning can all damage them, and this damage is difficult to avoid during cleaning. Alcohol cleaning is a better option, but alcohol, being a strong solvent, also damages the tubes, affecting their lifespan. Existing technologies include coatings to isolate solvent damage, such as PVDF (polyvinylidene fluoride) coatings, which offer excellent resistance to most acids, alkalis, salts, and solvents. However, the coating has weak adhesion, requiring surface roughening during spraying. Roughening the centrifuge tubes leaves micro-cracks on their surface, which, under high-speed rotation and high gravitational acceleration, can lead to further crack development and ultimately centrifuge tube breakage. Therefore, applying a coating to the surface of high-strength centrifuge tubes is a technical challenge in the current technology. It should be noted that this preparation method must also be within an economically viable range. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a centrifuge tube for an ultracentrifuge that is easy to clean. An anti-corrosion coating can be easily applied to the inner wall of the centrifuge tube, allowing for convenient cleaning of the tube within economically feasible conditions. In a preferred embodiment, it is possible to easily test whether the strength of the centrifuge tube meets the usage requirements.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: a centrifuge tube for an ultracentrifuge that is easy to clean, wherein the inner wall of the centrifuge tube is coated with a PVDF coating.

[0005] Its preparation method includes the following steps:

[0006] S1. Centrifuge tubes are manufactured by blow molding;

[0007] S2. After the centrifuge tubes are formed, a PVDF mixed solution is sprayed into the mold.

[0008] S3. Cooling and drying;

[0009] The above steps enable the preparation of easily cleanable centrifuge tubes for ultracentrifuges.

[0010] In the preferred embodiment, in step S1, the centrifuge tube is made of PC.

[0011] PC granules were pre-dried at 120℃±5℃ for 4~8 hours;

[0012] During blow molding, the material temperature is 300℃±10℃, and the mold temperature is 80°C to 95°C.

[0013] In a preferred embodiment, in step S2, PVDF is mixed with one of NMP, DMAc, or DMF to form a mixed solution;

[0014] The PVDF mixed solution is sprayed onto the inner wall of the centrifuge tube during molding by rotating the sprayer from top to bottom and then from top to bottom 1 to 3 times.

[0015] In the preferred embodiment, in step S2, at room temperature, the ratio of PVDF to NMP is 10-50% of the total weight of PVDF;

[0016] Alternatively, the ratio of PVDF to DMAc can be 10% to 30% of the total weight of PVDF;

[0017] Alternatively, the ratio of PVDF to DMF can be 10% to 30% of the total weight;

[0018] The spraying time is when the centrifuge tubes being formed have cooled to below 85°C.

[0019] In a preferred embodiment, a spray tube is provided on the blow molding head of the mold, the spray tube slides up and down along the axis of the centrifuge tube, and rotates along the axis;

[0020] Multiple nozzles are installed at the bottom of the spray tube, and a valve stem is installed at the center of the spray tube. A valve head is installed at the bottom of the valve stem. When the spray tube reaches the upper limit position, the valve head blocks the channel of the spray tube. When the spray tube leaves the upper limit position, the valve head opens the channel of the spray tube.

[0021] In a preferred embodiment, the spraying pipe is connected to the slurry inlet pipe via a rotary joint. A servo motor is fixed on the rotary joint. The servo motor contacts the spraying pipe via a friction wheel and drives the spraying pipe to rotate.

[0022] The valve stem is fixedly connected to the frame, and the frame is connected to the rotary joint via an electric push rod. The electric push rod is parallel to the axis of the valve stem to drive the rotary joint to reciprocate up and down.

[0023] In the preferred embodiment, S4 also includes an inspection step to check whether the strength of the centrifuge tube meets the strength requirements;

[0024] Specifically, it includes the following steps:

[0025] S41. Pressurize and fill the centrifuge tube with the medium;

[0026] S42. Pressurize and fill the centrifuge tube with the medium at 75% - 95% of the yield pressure of the centrifuge tube;

[0027] S43. Online monitor the diameter deformation of the centrifuge tube;

[0028] S44. Select the centrifuge tube that returns to the initial diameter as qualified.

[0029] In the preferred solution, the device for testing the strength of the centrifuge tube adopts the following structure:

[0030] It includes a plunger. A conduit is provided inside the plunger. The plunger is used to form a sealing structure with the bottle mouth of the centrifuge tube;

[0031] The conduit is connected to the output port of the pressure medium source;

[0032] A pressure sensor is provided on the conduit;

[0033] A diameter monitoring device is also provided. The diameter monitoring device is used to detect the diameter change of the centrifuge tube.

[0034] In the preferred solution, the plunger is fixedly arranged on the bottom plate. Bolts are also fixedly arranged on the bottom plate. A gland is also provided. The gland has holes corresponding to the bolts. The bolts pass through the holes and are connected to nuts. The centrifuge tube is used to be arranged between the bottom plate and the gland. The tube mouth of the centrifuge tube is sleeved on the plunger. A sealing ring is provided on the outer wall of the plunger;

[0035] A limiting ring is also fixedly arranged around the plunger. The limiting ring is located outside the tube mouth of the centrifuge tube and is used to limit the deformation of the tube mouth of the centrifuge tube;

[0036] 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. The outlet of the control valve is connected to the conduit;

[0037] The circulation port of the pressure regulating valve is connected to the inlet of the pump through a circulation pipe;

[0038] A buffer tank is also provided on the conduit. A compressed air bag is provided inside the buffer tank.

[0039] In the preferred solution, the structure of the diameter monitoring device is: a detection tape is wound around the outer wall of the centrifuge tube. One end of the detection tape 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 calculate the change in the diameter of the centrifuge tube according to the change in the circumference;

[0040] The displacement sensor includes a capacitive, grating or winding disk type displacement sensor.

[0041] The present invention provides a centrifuge tube for an ultracentrifuge that is easy to clean, and has the following beneficial effects:

[0042] 1. The method of the present invention can set an anti-corrosion coating inside the centrifuge tube with almost no damage. Since the spraying process is carried out immediately after blow molding, the anti-corrosion coating has high adhesion and is not easy to fall off during use, thus extending the service life of centrifuge tubes used in ultra-high speed centrifuges.

[0043] 2. The improved mold of this invention can be easily sprayed immediately after blow molding, which is very convenient to operate and can form a coating with uniform thickness.

[0044] 3. The testing device of the present invention ensures that the centrifuge tubes used can meet the usage requirements by monitoring the diameter deformation under pressure, thus avoiding damage to the centrifuge tubes under ultra-high speed conditions. Attached Figure Description

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0046] Figure 1 This is a flowchart of the centrifuge tube preparation method of the present invention;

[0047] Figure 2 This is a flowchart of the centrifuge tube inspection method of the present invention;

[0048] Figure 3 This is a schematic diagram of the centrifuge tube preparation mold of the present invention;

[0049] Figure 4 This is a partially enlarged schematic diagram of the spray nozzle in this invention;

[0050] Figure 5 This is a schematic diagram of the detection device of the present invention;

[0051] Figure 6 This is a schematic diagram of the capacitive diameter monitoring device of the present invention;

[0052] Figure 7 This is a schematic diagram of the structure of the grating-type diameter monitoring device of the present invention;

[0053] Figure 8 This is a schematic diagram of the structure of the winding disc diameter monitoring device of the present invention;

[0054] Figure 9 This is a schematic diagram of the pressure medium source of the present invention.

[0055] In the diagram: 1. Pressure cap; 2. Bolt; 3. Centrifuge tube; 4. Plunger; 5. Sealing ring; 6. Conduit; 7. Pressure medium source; 71. Circulation pipe; 72. Pump; 73. Pressure regulating valve; 74. Buffer tank; 75. Compression air bag; 8. Pressure sensor; 9. Control valve assembly; 10. 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 strip. 07; grating head 108; grating guide rail 109; angle sensor 110; winding disc 111; detection belt 11; exhaust valve 12; base 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 Implementation

[0056] like Figure 1-9 As shown, a centrifuge tube for an ultracentrifuge that is easy to clean has a PVDF coating on the inner wall of the centrifuge tube 3.

[0057] Its preparation method includes the following steps:

[0058] S1. Centrifuge tubes 3 are prepared by blow molding;

[0059] S2. After the centrifuge tubes 3 are formed, a PVDF mixed solution is sprayed into the mold.

[0060] S3. Cooling and drying;

[0061] The above steps enable the preparation of easily cleanable centrifuge tubes for ultracentrifuges.

[0062] like Figure 1 As shown, this embodiment prepares easily cleanable centrifuge tubes for ultracentrifuges through steps such as blow molding, spraying with a PVDF mixed solution, and cooling and drying. Reasonable material selection, process control, and quality inspection are implemented during the preparation process to ensure that the performance and quality of the centrifuge tubes reach optimal levels. The following is a detailed description of each step:

[0063] In step S1, the medium is pressurized and filled into the new centrifuge tube 3, and the diameter deformation of the centrifuge tube 3 is detected online.

[0064] In this example, centrifuge tube 3 is made of PVC or PC. In a preferred embodiment, the filling medium is either air or water. Alternatively, water is used as the filling medium for PVC centrifuge tube 3, and compressed air is used as the filling medium for PC centrifuge tube 3.

[0065] PVC (polyvinyl chloride) is a thermoplastic, divided into two main categories: flexible PVC and rigid PVC. This example uses rigid PVC. PC (polycarbonate) is an engineering plastic with high strength and toughness.

[0066] In the preferred embodiment, in step S1, the centrifuge tube 3 is made of PC.

[0067] PC granules were pre-dried at 120℃±5℃ for 4~8 hours;

[0068] During blow molding, the material temperature is 300℃±10℃, and the mold temperature is 80°C to 95°C.

[0069] In this embodiment, by setting a reasonable temperature and pre-drying time, the moisture in the PC particles was fully removed, eliminating the potential impact of air bubbles generated during the process, thereby improving product quality. The mold temperature ensured that the strength and internal stress distribution of the PC were uniform during the blow molding process.

[0070] In a preferred embodiment, in step S2, PVDF (polyvinylidene fluoride) is mixed with one of NMP (N-methylpyrrolidone), DMAc (dimethylacetamide), or DMF (dimethylformamide) to form a mixed solution;

[0071] The PVDF mixed solution is sprayed onto the inner wall of the centrifuge tube 15 during molding by rotating the sprayer from top to bottom and then from top to bottom 1 to 3 times.

[0072] In the preferred embodiment, in step S2, at room temperature, the ratio of PVDF to NMP is 10-50% of the total weight of PVDF;

[0073] Alternatively, the ratio of PVDF to DMAc can be 10% to 30% of the total weight of PVDF;

[0074] Alternatively, the ratio of PVDF to DMF can be 10% to 30% of the total weight;

[0075] The spraying time is when the centrifuge tube 15, which is being formed, cools down to below 85°C.

[0076] Example 2:

[0077] Further explanation in conjunction with Example 1, such as Figure 3-4 As shown, this is an apparatus suitable for the method of Embodiment 1.

[0078] In a preferred embodiment, a spray pipe 17 is provided on the blow molding head 16 of the mold. The spray pipe 17 slides up and down along the axis of the centrifuge tube 3 and rotates along the axis.

[0079] Multiple nozzles 21 are provided at the bottom of the spray tube 17. A valve stem 19 is provided at the center of the spray tube 17. 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 channel of the spray tube 17. When the spray tube 17 leaves the upper limit position, the valve head 20 opens the channel of the spray tube 17.

[0080] This embodiment achieves omnidirectional spraying of the inner wall of the centrifuge tube 3 by sliding and rotating the spray pipe 17, eliminating the need for manual adjustment of the spraying position, improving spraying efficiency, ensuring uniformity, and avoiding the problem of slurry dripping and sticking to the wall. A valve stem 19 and a valve head 20 are located at the center of the spray pipe 17, improving the precision of the spraying process control: when the spray pipe 17 reaches its upper limit position, the valve head 20 blocks the channel of the spray pipe 17 to prevent further solution outflow; when the spray pipe 17 leaves its upper limit position, the valve head 20 opens the channel, allowing the solution to flow out for spraying. This structure ensures that the spraying process is unaffected by the distance between the valve and the nozzle, allowing for rapid shut-off and avoiding delays, which is crucial for ensuring uniformity of the spraying.

[0081] In a preferred embodiment, the spray pipe 17 is connected to the slurry inlet pipe 22 via a rotary joint 18. A servo motor 25 is fixed on the rotary joint 18. The servo motor 25 contacts the spray pipe 17 via a friction wheel and drives the spray pipe 17 to rotate.

[0082] 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 drive the rotary joint 18 to move up and down reciprocally.

[0083] In this embodiment, the servo motor 25 and the electric push rod 24 are controlled by a PLC (Programmable Logic Controller) or a DCS (Distributed Control System), achieving precise control of the rotation speed, up-and-down sliding speed, and position of the spray pipe. The servo motor contacts and drives the spray pipe 17 to rotate through a friction wheel, which not only ensures control accuracy but also allows for flexible torque transmission and simplifies the transmission structure.

[0084] Example 3:

[0085] Further explanation in conjunction with Example 1, such as Figure 2 As shown, a detailed inspection procedure for the strength of centrifuge tube 3 is provided.

[0086] In the preferred embodiment, step S4 also includes an inspection step to check whether the strength of the centrifuge tube 3 meets the strength requirements, in order to avoid damage in the ultra-high speed centrifuge.

[0087] Specifically, the following steps are included:

[0088] S41. Pressurize centrifuge tube 3 and fill it with medium;

[0089] S42. Pressurize the centrifuge tube with 75% to 95% of the yield pressure of centrifuge tube 3 and fill it with medium.

[0090] S43. Monitor the diameter deformation of centrifuge tube 3 online;

[0091] S44. Centrifuge tube 3 with the restored initial diameter is considered qualified.

[0092] The strength of the complete centrifuge tube was tested through steps S41-S44. First, the initial diameter of centrifuge tube 3 was measured. The medium was then filled into the centrifuge tube until it reached 75%~95% of the centrifuge tube's yield pressure, and the change was monitored online. After reaching the predetermined pressure value and maintaining it for a period of time, the pressure was slowly released. Then, the diameter of the centrifuge tube was measured again and compared with the initial diameter before pressurization. If the diameter change was within the allowable range, the centrifuge tube was considered qualified.

[0093] In the preferred embodiment, the device for testing the strength of centrifuge tube 3 adopts the following structure:

[0094] Includes a plunger 4, which has a conduit 6 inside. The plunger 4 is used to form a sealing structure with the bottle mouth of the centrifuge tube 3.

[0095] Conduit 6 is connected to the output port of pressure medium source 7;

[0096] A pressure sensor 8 is installed on the conduit 6;

[0097] It is also equipped with a diameter monitoring device, which is used to detect changes in the diameter of centrifuge tube 3.

[0098] like Figure 5 As shown, this embodiment is used to test the strength of the centrifuge tubes to ensure they can withstand a certain pressure. The pressure medium source 7 is a device that provides the pressure medium, which can be an air pump, a water pump, or other device capable of providing stable pressure.

[0099] In the preferred scheme, such as Figure 5 As shown, the plunger 4 is fixed on the base plate 13, and the base plate 13 is also fixed with bolts 2 and a pressure cap 1. The pressure cap 1 has holes corresponding to bolts 2. Bolts 2 pass through the holes and are connected to nuts. Centrifuge tube 3 is used to be set between the base plate 13 and the pressure cap 1. The opening of centrifuge tube 3 is sleeved on the plunger 4. A sealing ring 5 is provided on the outer wall of the plunger 4.

[0100] like Figure 3As shown, a limiting ring 26 is also fixed around the plunger 4. The limiting ring 26 is located around the opening of the centrifuge tube 3 and is used to limit the deformation of the opening of the centrifuge tube 3.

[0101] like Figure 9 As shown, 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.

[0102] The circulation port of the pressure regulating valve 73 is connected to the inlet of the pump 72 through the circulation pipe 71;

[0103] A buffer tank 74 is also provided on the conduit 6, and a compression airbag 75 is provided inside the buffer tank 74.

[0104] 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 facilitate the opening or closing of the medium delivery as needed during the inspection process.

[0105] The pressure medium source 7 is used by setting the circulating 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 fluctuations of the plunger pump. In use, the circulating pressure of the pressure regulating valve 73 is first set, causing the pump 72 to continuously supply the pressure medium to the buffer tank 74 at the preset pressure until the pressure reaches the preset value. Then, the pump 72 is turned off, and the pressure is maintained by the one-way valve at the outlet of the pump 72. The pressure of the pressure sensor 8 is checked to see if it has reached the preset value. The set pressure is usually higher than the pressure required for the experiment because some pressure is lost when the control valve is opened. 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 pressure is released by the exhaust valve 12, and a new centrifuge tube 3 is reinstalled for testing.

[0106] In the preferred scheme, such as Figure 5 As shown, the structure of the diameter monitoring device is as follows: the 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 the fixed displacement sensor 10 to detect the change in the circumference of the centrifuge tube 3, and calculate the change in the diameter of the centrifuge tube 3 based on the change in circumference.

[0107] The displacement sensor 10 includes capacitive, grating, or wound disk displacement sensors.

[0108] In this embodiment, the travel diameter monitoring device uses a detection head to contact the outer wall of the centrifuge tube 3 and measures the displacement of the detection head in a mechanical, electromagnetic, or photoelectric manner. The diameter change of the centrifuge tube 3 is calculated based on the displacement of the detection head. Taking a micrometer as an example, the detection end of the micrometer is brought into contact 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 value of the diameter change is obtained from the displacement of the micrometer detection rod.

[0109] For some plastics, such as PC, the breaking pressure and yield pressure values ​​are quite close, thus requiring precise detection of diameter changes. The circumference-diameter monitoring device uses a detection strip 11 wound around the outer wall of the centrifuge tube 3. One end of the detection strip 11 is fixed, and the other end is connected to a fixed displacement sensor 10 to detect changes in the circumference of the centrifuge tube 3, and the diameter change of the centrifuge tube 3 is calculated based on the circumference change. This structure provides the highest detection accuracy, reaching up to the nanometer level. This ensures accurate detection results, avoiding excessive pressure differences that could damage the centrifuge tube 3 or cause defective centrifuge tubes to pass the inspection. Circumference change detection can be achieved through the following methods:

[0110] 1) Capture images of centrifuge tube 3 and detect changes in the diameter of centrifuge tube 3 based on the images; during detection, use a high-definition camera, such as a 4K camera, to capture images of the middle position of centrifuge tube 3. After calibration, match the image pixels with the diameter data. By identifying the edge of centrifuge tube 3, obtain the diameter of centrifuge tube 3 based on the pixel data.

[0111] 2) Detect the diameter change of centrifuge tube 3 using a beam array; detect the centrifuge tube by multiple array beams. When the diameter of centrifuge tube 3 changes, more beams are blocked. By matching the position of the beam array with the diameter data, the diameter of centrifuge tube 3 can be obtained.

[0112] 3) Use laser or sonar to detect the distance between the transmitter head and the outer wall of centrifuge tube 3, and calculate the diameter change of centrifuge tube 3 based on the distance change; the position of the transmitter head is fixed, and the transmitter head first emits laser or sonar, and the distance between the transmitter head and the outer wall of centrifuge tube 3 is calculated based on the flight time of the reflected light or reflected wave. Based on the distance change, the diameter change of centrifuge tube 3 is calculated.

[0113] The displacement sensor 10 in this embodiment includes a capacitive, grating, or wound disk displacement sensor, as detailed below:

[0114] 1) The capacitive displacement sensor 10 has the following structure: a detection band 11 passes between the first electrode layer 101 and the second electrode layer 102. An insulating section 104 and an electrode dielectric section 105 are provided on the detection band 11, wherein the lengths of the insulating section 104 and the electrode dielectric section 105 are equal, and their lengths are slightly larger than the range of circumferential deformation of the centrifuge tube 3. For example, the ratio of the lengths of the insulating section 104 and the electrode dielectric section 105 to the circumferential deformation of the centrifuge tube 3 is 1.2:1. A damper 103 is also provided to provide damping for the detection band 11. By detecting the capacitance change between the first electrode layer 101 and the second electrode layer 102, the deformation value of the centrifuge tube 3 can be obtained, and then the diameter change of the centrifuge tube 3 can be calculated.

[0115] 2) The structure of the grating displacement sensor 10 is as follows: the grating guide rail 109 is fixedly installed, the grating head 108 is slidably connected to the grating guide rail 109, and the grating head 108 is fixedly connected to the detection belt 11. The deformation of the perimeter of the centrifuge tube 3 causes the grating head 108 to move, thereby obtaining the deformation value of the perimeter of the centrifuge tube 3, and then calculating the change in the diameter of the centrifuge tube 3. The structure of grating displacement detection is existing technology.

[0116] 3) The structure of the winding disc displacement sensor is as follows: the winding disc 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 disc 111. The detection belt 11 is wound on the winding disc 111. Let the position of the winding disc 111 when it is wound on the centrifuge tube 3 be the initial position, i.e., the zero position. During the experiment, the diameter deformation of the centrifuge tube 3 causes the detection belt 11 to move, thereby causing the winding disc 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.

[0117] like Figure 6 As shown, in this embodiment, one end of the detection belt 11 is fixedly connected to the bolt 2 via a fixing connector 106. Preferably, the detection belt 11 is a metal belt, the fixing connector 106 is a hook with a magnet, and the displacement sensor 10 is fixedly connected to the current bolt or another bolt; that is, the displacement sensor 10 can be fixed to the current bolt or to 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 change in length of the detection belt 11 is linearly related to the change in diameter. Therefore, the change in diameter of the centrifuge tube 3 can be accurately calculated based on the change in length of the detection belt 11.

[0118] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The embodiments and features described in these embodiments can be arbitrarily combined without conflict. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A centrifuge tube for use in an ultracentrifuge which facilitates cleaning, characterized by: The inner wall of the centrifuge tube (3) is coated with PVDF. Its preparation method includes the following steps: S1. Centrifuge tubes (3) are prepared by blow molding; the material of centrifuge tubes (3) is PC; PC granules were pre-dried at 120℃±5℃ for 4~8 hours; During blow molding, the material temperature is 300℃±10℃, and the mold temperature is 80°C to 95°C. S2. After the centrifuge tube (3) is formed, a PVDF mixed solution is sprayed into the mold; in step S2, PVDF is mixed with one of NMP, DMAc or DMF to form a mixed solution. In the mold, a PVDF mixed solution is sprayed onto the inner wall of the centrifuge tube (15) during molding by rotating and spraying 1 to 3 times from top to bottom and then from top to bottom. At room temperature, the ratio of PVDF to NMP is 10% to 50% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMAc can be 10% to 30% of the total weight of PVDF; Alternatively, the ratio of PVDF to DMF can be 10% to 30% of the total weight; The spraying time is when the centrifuge tube (15) is cooled to below 85°C during the molding process; A spray tube (17) is provided on the blow head (16) of the mold. The spray tube (17) slides up and down along the axis of the centrifuge tube (3) and rotates along the axis. Multiple nozzles (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). A valve head (20) is provided at the bottom of the valve stem (19). When the spray pipe (17) reaches the upper limit position, the valve head (20) blocks the channel of the spray pipe (17). When the spray pipe (17) leaves the upper limit position, the valve head (20) opens the channel of the spray pipe (17). S3. Cooling and drying; S4 also includes an inspection step to check whether the strength of the centrifuge tube (3) meets the strength requirements; Specifically, the following steps are included: S41. Pressurize and fill the centrifuge tube (3) with the medium; S42. Pressurize the centrifuge tube (3) with 75%~95% of its yield pressure and fill it with medium. S43. Monitor the diameter deformation of the centrifuge tube (3) online; S44. Centrifuge tubes (3) with restored initial diameter are considered qualified; The above steps enable the preparation of easily cleanable centrifuge tubes for ultracentrifuges.

2. The easy-to-clean centrifuge tube for an ultracentrifuge according to claim 1, characterized in that The spray pipe (17) is connected to the slurry inlet pipe (22) through a rotary joint (18). A servo motor (25) is fixed on the rotary joint (18). The servo motor (25) contacts the spray pipe (17) through a friction wheel and drives the spray 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) to drive the rotary joint (18) to move up and down reciprocally.

3. The easy-to-clean centrifuge tube for an ultracentrifuge according to claim 2, characterized in that: The device for testing the strength of centrifuge tubes (3) has the following structure: Includes a plunger (4), which has a conduit (6) inside. 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, which is used to detect changes in the diameter of the centrifuge tube (3).

4. The centrifuge tube for an ultracentrifuge that is easy to clean according to claim 3, characterized in that: The plunger (4) is fixed on the base plate (13). A bolt (2) is also fixed on the base plate (13). A pressure cap (1) is also provided. The pressure cap (1) has a hole corresponding to the bolt (2). The bolt (2) passes through the hole and is connected to the nut. The centrifuge tube (3) is used to be set between the base plate (13) and the pressure cap (1). The opening 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 fixed around the plunger (4). The limiting ring (26) is located around the opening of the centrifuge tube (3) and is used to limit the deformation of the opening 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 conduit (6), and a compression airbag (75) is provided inside the buffer tank (74).

5. The centrifuge tube for an ultracentrifuge that is easy to clean according to claim 3, characterized in that: The structure of the diameter monitoring device is as follows: the 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 calculate the change in the diameter of the centrifuge tube (3) based on the change in circumference. The displacement sensor (10) includes capacitive, grating or spiral disk displacement sensors.

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