The processing method that the centrifuge rotor cannot be taken out
Guo Jian, He Chunze, Cheng Huan
(Laboratory Instrument Factory, Academy of Military Medical Sciences, Beijing 100850, China)
[Abstract] This paper analyzes that the reason why the centrifuge rotor cannot be removed from the centrifugal chamber is that the rotor is bonded to the spindle of the centrifuge motor due to improper use. Combined with the maintenance practice, two treatment methods are introduced, which are suitable for the user's own processing and professional processing, and prompt the precautions in the process. Several precautions have been proposed for the cause of the failure, namely: correct use and timely routine maintenance. At the same time, it summarizes the importance of choosing the right tool in the instrument maintenance process.
[Key words] centrifuge; rotor; puller; prevention
Solution for Centrifuge Rotor Taken out
GUO Jian, He Chunze, Cheng Huan
(Experimental Instrument Plant, Academy of Military Medical Sciences, Beijing 100850, China)
Abstract The reason for which the centrifuge rotor can not be taken out from the chamber is analyzed, that is rotor and motor spindle are bonded together due to improper use. Two solutions for this problem are introduced, which are suitable for users and professionals. For maintenance are prompted. Several preventive measures are also put forward, which are proper use and timely maintenance. The importance of selecting appropriate tools is also summarized during maintenance.
Key Words centrifuge;rotor;drawing device; prevention
Centrifuges are commonly used in laboratory equipment for the separation, preparation, concentration and purification of substances [1]. The rotor is one of the core components of the centrifuge, and proper use and maintenance are important. In our laboratory, it is often the case that the rotor cannot be removed from the centrifuge chamber due to improper use. The author summarizes the two treatment methods in combination with their own maintenance practices, for the reference of the users and instrument maintenance managers.
1 Cause analysis
The fact that the rotor cannot be removed from the centrifuge chamber is mainly due to the bonding of the rotor to the spindle of the centrifuge motor. As shown in Figure 1, it is a common way to install the centrifuge head. The rotor is mounted on a motor shaft with a tapered surface and fastened by a locking screw. Due to the condensation process, there may be condensed water or inadvertently spilled liquid between the main shaft and the center hole of the rotor. When the centrifuge is finished, if the rotor is not pulled out in time, it will be used continuously for a long time. Corrosion and bonding occur with the rotor, which ultimately prevents the operator from taking the rotor [2]. Such phenomena are more likely to occur on high speed refrigerated centrifuges.
About the author: Guo Jian (1981—), male, Henan Weihui, engineer, mainly engaged in quality control, measurement and maintenance of medical laboratory instruments, E-mail:.
Corresponding author: Cheng ring, E-mail:
2 Processing methods
2.1 Simple method
First unscrew the original locking screw and screw it into the threaded hole of the spindle with a screw of the same thread size. Note that the end is not completely screwed in. The two cooperate, one person holds the rotor with both hands and lifts it up slightly. Be careful not to use too much force to avoid deforming the motor support frame. Another person uses a hammer to tap the screw at the upper end of the motor spindle through a thin rod. After repeated several times, the rotor can generally be disengaged from the spindle.
2.2 Special tool method
If the above method cannot take out the rotor, it indicates that the bonding is serious. It is possible to first add a rust remover to the joint of the main shaft and the rotor for rust removal and wetting. After waiting for a day or so, use a dedicated puller to remove the rotor. As shown in Figure 2, the schematic drawing of the puller for the puller. Similarly, first select the appropriate size of the puller according to the size of the rotor, then pull the puller to the bottom of the rotor, the head of the puller screw against the screw in the threaded hole of the spindle, the position of the puller After the righting, use a wrench to rotate the screw clockwise. According to the mechanical principle of the screw, the puller of the puller will generate a large pulling force to disengage the rotor from the spindle.
2.3 Points to note
(1) Either way, be sure to insert a replacement screw into the threaded hole of the spindle to protect the spindle thread and the original locking screw. Otherwise, if the original thread is damaged, the motor may be scrapped.
(2) Use force to master the measurement, do not brute force. When the resistance is too large, the wetting time of the rust remover can be prolonged.
(3) After the rotor is removed, the outer surface of the spindle and the inner surface of the rotor should be ground with fine sandpaper to remove the rust and grease to prevent re-bonding.
3 Precautions
(1) Strengthen daily maintenance, the joint surface of the rotor and the spindle should be wiped clean and greased [3].
(2) Especially for refrigerated centrifuges, do not close the door immediately after use. The moisture, condensate and corrosive gases in the centrifuge chamber should be volatilized, return to normal temperature, and then close the door.
(3) Remove the rotor in time for each centrifugation. If a rotor is not replaced or taken out for many days, it is easy to cause adhesion. In the worst case, the whole machine will be scrapped.
(4) Do not use too much force each time the screw is tightened. Otherwise, the screw slip will be tripped. In severe cases, the motor will be scrapped. Because the motor generally rotates counterclockwise, when the acceleration is accelerated, the inertia screw itself generates a clockwise tightening force, which can just make the rotor fasten. Therefore, as long as the wrist feels slightly weak, the wrist can be tightened.
4 Summary
"If you want to do something good, you must first sharpen your tools." As an instrument maintenance support personnel, you should know more about the selection of various delicate maintenance tools. When the user purchases the instrument, the user should request the manufacturer to configure the special maintenance tool [4]. Sometimes an inconspicuous repair tool can bring the endangered instruments back to life and save limited research funding.
[references]
[1] Huang Yilin. Principle, construction and maintenance of medical electric instruments [M]. Beijing: China Medical Science and Technology Press, 1999:42.
[2] Liu Ming, Zhao Qi. The use and maintenance of centrifuges [J]. Modern Instrument, 2003 (6): 50-55.
[3] Chen Shijun, Tang Hairong, Zhang Zhaopei, et al. Principle, operation and maintenance of centrifuges [J]. Modern Scientific Instruments, 2010 (3): 151-154.
[4] Gu Xiaoming. Daily maintenance and maintenance of large medical equipment [J]. Shanghai Medical, 2012, 33 (3): 51-52.
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