离心风机是一种将原动机的机械能转换为输送气体、给予气体能量的机械,它是火电厂中不可少的机械设备,主要有送离心风机、引离心风机、一次离心风机、密封离心风机和排粉机等,消耗电能约占发电厂发电量的1.5%~3.0%。在火电厂的实际运行中,离心风机,特别是引离心风机由于运行条件较恶劣,故障率较高,据有关统计资料,引离心风机平均每年发生故障为2次,送离心风机平均每年发生故障为0.4次,从而导致机组非计划停运或减负荷运行。因此,迅速判断离心风机运行中故障产生的原因,采取得力措施解决是发电厂连续安全运行的保障。虽然离心风机的故障类型繁多,原因也很复杂,但根据调查电厂实际运行中离心风机故障较多的是:轴承振动、轴承温度高、动叶卡涩、保护装置误动。
The centrifugal fan is a machine that converts the mechanical energy of the original motive into the gas and gives the energy of the gas. It is an indispensable mechanical equipment in the thermal power plant. It mainly includes the centrifugal fan, the centrifugal fan, the centrifugal fan, the sealed centrifugal fan and the pulverized machine. The energy consumption is about 1.5% to 3 of the power generation capacity of the power plant. .0%. In the actual operation of the thermal power plant, the centrifugal fan, especially the centrifugal fan, has a high failure rate because of the bad operating conditions. According to the relevant statistical data, the average failure of the centrifugal fan is 2 times a year, and the average failure of the centrifugal fan is 0.4 times a year, thus leading to the unplanned outage or load reduction operation of the unit. . Therefore, it is necessary to quickly determine the cause of the faults in the centrifugal fan operation and take effective measures to solve the problem, which is the guarantee for the continuous and safe operation of the power plant. Although the fault types of centrifugal fans are various and the reasons are very complicated, there are many faults of centrifugal fans in the actual operation of the power plant: bearing vibration, high bearing temperature, acerbic movable leaf card, and malfunction of protection device.
1 离心风机轴承振动超标
离心风机轴承振动是运行中常见的故障,离心风机的振动会引起轴承和叶片损坏、螺栓松动、机壳和风道损坏等故障,严重危及离心风机的安全运行。离心风机轴承振动超标的原因较多,如能针对不同的现象分析原因采取恰当的处理办法,往往能起到事半功倍的效果。
1 centrifugal fan bearing vibration exceeding standard
The vibration of centrifugal fan bearing is a common fault in operation. The vibration of centrifugal fan will cause damage of bearing and blade, loosening of bolt, damage of casing and air duct and so on, which seriously endangers the safe operation of centrifugal fan. There are many reasons why the bearing vibration of the centrifugal fan is exceeding the standard. If we can take appropriate measures to analyze the causes of different phenomena, it can often result in twice the result with half the effort.
1.1 不停炉处理叶片非工作面积灰引起离心风机振动
这类缺陷常见于锅炉引离心风机,现象主要表现为离心风机在运行中振动突然上升。这是因为当气体进入叶轮时,与旋转的叶片工作面存在一定的角度,根据流体力学原理,气体在叶片的非工作面一定有旋涡产生,于是气体中的灰粒由于旋涡作用会慢慢地沉积在非工作面上。机翼型的叶片最易积灰。当积灰达到一定的重量时由于叶轮旋转离心力的作用将一部分大块的积灰甩出叶轮。由于各叶片上的积灰不可能完全均匀一致,聚集或可甩走的灰块时间不一定同步,结果因为叶片的积灰不均匀导致叶轮质量分布不平衡,从而使离心风机振动增大。
在这种情况下,通常只需把叶片上的积灰铲除,叶轮又将重新达到平衡,从而减少离心风机的振动。在实际工作中,通常的处理方法是临时停炉后打开离心风机机壳的人孔门,检修人员进入机壳内清除叶轮上的积灰。这样不仅环境恶劣,存在不安全因素,而且造成机组的非计划停运,检修时间长,劳动强度大。经过研究,提出了一个经实际证明行之有效的处理方法。在机壳喉舌处(A点,径向对着叶轮)加装一排喷嘴(4~5个),将喷嘴调成不同角度。喷嘴与冲灰水泵相连,将冲灰水作为冲洗积灰的动力介质,降低负荷后停单侧离心风机,在停离心风机的瞬间迅速打开阀门,利用叶轮的惯性作用喷洗叶片上的非工作面,打开在机壳底部加装的阀门将冲灰水排走。这样就实现了不停炉而处理离心风机振动的目的。用冲灰水作清灰的介质,和用蒸汽和压缩空气相比,具有对喷嘴结构要求低、清灰范围大、效果好、对叶片磨损小等优点。
1.1 the non working area of the blades is caused by the non working area ash and causes the vibration of the centrifugal fan.
This kind of defect is commonly found in the centrifugal fan of the boiler. The phenomenon is mainly caused by the sudden rise in the vibration of the centrifugal fan in operation. This is because when the gas enters the impeller, there is a certain angle with the rotating blade working face. According to the principle of fluid mechanics, there must be a whirlpool in the non working surface of the blade, so the ash particles in the gas will be slowly deposited on the non working surface because of the vortex action. The blade of the wing is the most easy to ash. When the ash reaches a certain weight, a large mass of ash is thrown out of the impeller due to the centrifugal force of the impeller. Because the ash on each blade can not be completely uniform, the time of the aggregate or flung ash is not always synchronized. The result is uneven distribution of the mass distribution of the impeller, which causes the vibration of the centrifugal fan to increase.
In this case, the ash is usually removed and the impeller will be re balanced so as to reduce the vibration of the centrifugal fan. In the actual work, the usual treatment method is to open the door of the centrifugal fan shell after the temporary stop of the furnace, and the overhauler enters the casing to clear the ash on the impeller. This is not only a bad environment, there are unsafe factors, but also cause unplanned outage of the unit, long maintenance time and strong labor intensity. After research, a practical method is proved to be effective. Install a row of nozzles (4~5) at the throat of the housing (A point, radial to the impeller), and adjust the nozzles to different angles. The nozzle is connected with the ash water pump, and the ash water is used as the dynamic medium for washing ash. After reducing the load, the single side centrifugal fan is stopped. The valve is opened quickly in the moment of the centrifugal fan. The non working face on the blade is sprayed with the inertia of the impeller, and the valve will be opened in the bottom of the shell to remove the ash water. In this way, the vibration of centrifugal fan can be treated without stopping the furnace. Compared with steam and compressed air, the medium with ash water as clear ash has the advantages of low requirement for nozzle structure, large cleaning range, good effect and small wear to blade.
1.2 不停炉处理叶片磨损引起的振动
磨损是离心风机中最常见的现象,离心风机在运行中振动缓慢上升,一般是由于叶片磨损,平衡破坏后造成的。此时处理离心风机振动的问题一般是在停炉后做动平衡。根据离心风机的特点,经过多次实践,总结了以下可在不停炉的情况下对离心风机进行动平衡试验工作。
1)在机壳喉舌径向对着叶轮处加装一个手孔门,因为此处离叶轮外圆边缘距离最近,只有200 mm多,人站在离心风机外面,用手可以进行内部操作。离心风机正常运行的情况下手孔门关闭。
2)振动发生后将离心风机停下(单侧停离心风机),将手孔门打开,在机壳外对叶轮进行试加重量。
3)找完平衡后,计算应加的重量和位置,对叶轮进行焊接工作。
1.2 vibration induced vibration of blade wear
Wear is the most common phenomenon in centrifugal fans, and the vibration of centrifugal fans increases slowly during operation. At this point, the problem of centrifugal fan vibration is usually done after dynamic shutdown. According to the characteristics of the centrifugal fan, after many practices, the following experiments can be done to balance the action of the centrifugal fan under the condition of no furnace.
1) add a hand gate to the impeller at the throat of the shell, because the distance from the round edge of the impeller is most recently, only 200 mm, the person is standing outside the centrifugal fan, and the hand can be operated inside. When the centrifugal fan operates normally, the hand door is closed.
2) after the vibration occurs, the centrifugal fan is stopped (the centrifugal fan is stopped on one side), the hand hole door is opened, and the impeller is added to the outside of the casing for trial weight.
3) after finding the balance, calculate the weight and position that should be added and weld the impeller.
在实际工作中,用三点法找动平衡较为简单方便。试加重量的计算公式为
P<=250×A0×G/D(3000/n)2(g)
为了尽快找到应加的重量和位置,应根据平时的数据多总结经验。根据经验,Y4-73-11-22D的离心风机振动0.10 mm时不平衡重量为2 000 g;M5-29-11-18D的排粉机振动0.10 mm时不平衡重量120 g;轴流ASN2125/1250型引离心风机振动为0.10 mm时不平衡重量只有80 g左右。为了达到不停炉处理叶片磨损引起的振动问题的目的,平时须加强对风门挡板的维护,减少风门挡板的漏风,在单侧离心风机停运时能防止热风从停运的送离心风机处漏出以维持良好的工作环境。
In practical work, it is simpler and more convenient to use three point method to find dynamic balance. The calculation formula for adding weight
P < = 250 * A0 x G / D (3000 / N) 2 (g)
In order to find the weight and position that should be added as soon as possible, we should sum up experience according to the usual data. According to experience, the unbalanced weight of Y4 73-11 22D centrifugal fan is 2000 g while the vibration of the centrifugal fan is 0.10 mm; the vibration of M5 29-11 18D pulverer is 0.10 mm and the unbalanced weight is 120 g; the unbalance weight of the axial flow ASN2125 / 1250 type centrifugal fan is about 80 g when the vibration of the centrifugal fan is 0.10 mm. In order to achieve the purpose of vibration problems caused by the non stop furnace treatment of blade wear, it is necessary to strengthen the maintenance of the door baffle, reduce the air leakage of the door baffle, and prevent the hot air from escaping from the outable centrifugal fan to maintain a good working environment when the single side centrifugal fan is stopped.
管理员刚刚
暂无任何留言!