The analysis of the drive components of the centrifuge was carried out. According to the analysis, the cause of the vibration is multi-factor, which mainly includes the residual unbalance of the rotor, the residual unbalance of the rotor of the motor, the connection mode of the motor and the drive assembly, and the setting of the damper. According to the kinetic principle, the equation for the rotor when operating at a certain speed is G + M (e + y) CO : (y + y).
The most influential one is the eccentricity e and the deflection Y of the rotor, which are related to the manufacturing precision of the rotor, the geometry of the drive shaft and the bearing position of the bearing. The source will cause simultaneous radial and axial vibrations, mainly in the radial direction. Based on this principle, we carefully analyzed the original design and found that the original structure does not have any damping device in the radial direction, and the vibration is repeated in the axial direction.
Second, the influence of the rotor and the rotor cover was found to have a clearance of 2 ram between the original rotor and the rotor cover. Third, the impact of the flexible coupling. Since the rotor and the motor always have different levels of residual unbalance, the two imbalances are two different sources. In a high-speed centrifuge with a direct drive structure, the two source forks have to be connected, which requires designing a coupling that effectively isolates the two sources. The original design of the coupling is a nylon sleeve with a square hole. Although the nylon sleeve can provide a certain damping and vibration isolation effect, it cannot meet the requirements for use here. In response to the above problems, we first added a rubber isolation ring to the original drive structure to isolate the radial vibration. The gap between the rotor and the rotor cover was reduced from the original 2ram to 0.1mm. The coupling was made of the original nylon. The set is changed to the structure of the universal coupling as shown in Fig. 2. After the above changes, after the test, the rotational speed reached 20000 rPm in less than 3 minutes, and the self-vibration acceleration measured on the drive motor was 4 g.
Third, other factors affecting vibration
1. The choice of bearings.
2. The axial preload of the bearing. Through many experiments, it has been proved that the axial preload of the spring eliminates the internal clearance in the bearing and improves the vibration characteristics during operation in a series of cases.
3. The choice of grease. This type of high-speed rotating device, when using grease, it is best not to use too thick grease. The grease used originally is 7018 high speed grease. During the test, the viscosity of the grease was found to be too large. When the rotational speed was raised to 1 5000 rPm, the temperature rise of the drive motor reached 7O-8O °C. This is undoubtedly a disadvantage to the motor. Later, we selected the special high-speed bearing grease of No. 12, the effect is obviously improved, and the maximum temperature rise of the motor is only 4O ~ 5O °C.
4. The influence of the bearing support position on the drive shaft. We designed a shaft with a bearing support span of 49 mm, an overhanging portion of 65 ram, and an overhanging portion of 6 Ramo tested. It was found that the vibration frequency was reduced from the original 12000 rPm to 5000 rpm, and then the speed was increased, and the vibration increased sharply. Then the shaft with a bearing span of 46 ram, an overhanging part of 40 ram and an overhanging part with a diameter of 9 mm was designed. Meet the requirements for use.
Fourth, the conclusion
In solving the vibration problem of the drive components of the high-speed refrigerated centrifuge, we refer to the drive components of other high-speed refrigerated centrifuges to achieve the rotational performance.
In short, we have taken our own path in designing this drive component. The success of this work has certain reference value for the design and maintenance personnel of high-speed refrigerated centrifuges.
1. Both sterile and non-sterile masks are made in a 100,000-class dust-free workshop. Other indicators such as filtration efficiency or airflow resistance are all the same requirements. The difference lies in the final sterilization process of the finished product. The presence or absence of.
2. The sterile type is mainly because the things that need to be entered in medical places such as ICUs and operating rooms that need to strictly control the microbial environment are sterile, and will not cause other bacterial infections in patients.
3. Non-sterile masks can meet the microbial limit indicators after being made in the above-mentioned 100,000-level dust-free workshop. Product introduction of disposable medical surgical masks. In other words, non-sterile masks are strictly in accordance with the medical device management method The management is safe enough to meet the daily protection needs of the public.
Medical Face Mask,non woven medical mask,medical face mask 3 layers,disposables medical face mask
Suzhou Xuanweicheng Biotechnology Co., Ltd , https://www.xwc-medical.com