• 水泵密封的原理及要求
  • 本站编辑:振欣透平机械有限公司(原杭州振兴工业泵制造有限公司)发布日期:2018-01-18 10:17 浏览次数:pubd
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1填料密封的原理

The principle of 1 packing seal

在机械行业中填料密封主要用作动密封,常用作离心泵、压缩机、真空泵、搅拌机的转轴密封。填料装入填料腔以后,经压盖螺丝对它作轴向压缩,当轴与填料有相对运动时,由于填料的塑性,使它产生径向力,并与轴紧密接触。与此同时,填料中浸渍的润滑剂被挤出,在接触面之间形成油膜。由于接触状态并不是特别均匀的,接触部位便出现“边界润滑”状态,称为“轴承效应”;而未接触的凹部形成小油槽,有较厚的油膜,接触部位与非接触部位组成一道不规则的迷宫,起阻止液流泄漏的作用,此称“迷宫效应”。这就是填料密封的机理。良好的密封在于维持“轴承效应”和“迷宫效应”。也就是说,要保持良好的润滑和适当的压紧。若润滑不良,或压得过紧都会使油膜中断,造成填料与轴之间出现干摩擦,比较后导致烧轴和出现严重磨损。因此,我们需要经常对填料的压紧程度进行调节,使填料中的润滑剂在运行一段时间而有所流失之后,再挤出一些润滑剂,同时补偿填料因体积变化所造成的压紧力松弛。当然这样经常挤压填料,比较后将使浸渍剂枯竭,所以定期更换填料是必要的。此外,为了维持液膜和带走摩擦热,有意让填料处有少量泄漏也是必要的。

In the machinery industry, packing seals are mainly used as dynamic seals, often used as centrifugal pumps, compressors, vacuum pumps, and rotating shaft seals of agitator. Packing into the packing cavity after the gland screws on it when the axial compression, and the filler has the relative motion, because the plastic filler to produce a radial force, and close contact with the shaft. At the same time, the lubricant impregnated in the filler is squeezed out and the oil film is formed between the contact surfaces.  Because the contact state is not uniform, the contact parts will appear the boundary lubrication condition, known as the "bearing effect"; the concave without contact to form a small oil tank, oil film thickness, contact and non-contact parts of an irregular maze, preventing the liquid leakage flow this effect, called "labyrinth effect". This is the mechanism of packing seal. Good seal is to maintain "bearing effect" and "labyrinth effect". That is to say, it is necessary to maintain good lubrication and appropriate pressure. If the lubrication is bad, or the pressure is too tight, the oil film will be interrupted, causing dry friction between the packing and the shaft, and finally causing the burning shaft and serious wear. Therefore, we need to adjust the packing degree of the packing regularly, so that the lubricant in the filler will run away for a period of time, and then squeeze out some lubricants, and compensate for the tightening force caused by the volume change of the filler. Of course, the packing is often squeezed, and the impregnating agent will be exhausted at the end, so it is necessary to replace the packing regularly. In addition, in order to maintain the liquid film and take away the friction heat, it is also necessary to have a small amount of leakage at the packing.

2.2填料密封在工业泵使用中存在的问题

Problems in the use of 2。2 packing seal in the use of industrial pumps

青龙棋牌官网工业泵的轴封一般采用具有耐磨性、耐热性、柔软性好、强度高等优点,我们在用盘根填料,发现其具以下个缺点:①填料表面粗糙、摩擦系数大、有渗漏现象,另外使用久了浸入的润滑剂容易流失。②新修好的设备,开始运行时轴封状况良好,但用不了多久,泄漏量便不断增加,调整压盖和更换填料的工作也逐渐频繁,运转不到一个周期,轴套就已磨损成花瓶状,严重时还会出现轴套磨断,并且水封环后面更换不到的盘根填料均已腐烂,无法起到密封作用。③填料与轴直接接触,且相对转动,造成轴与轴套的磨损,所以必须定期或不定期更换轴套。④为了使盘根与轴或轴套间产生的摩擦热及时散掉,盘根密封必须保持一定量的泄漏,而且不易控制。⑤盘根与轴或轴套间的摩擦,造成电机有效功率降低,消耗电能。

The industrial pump generally adopts abrasion resistance, heat resistance, good flexibility, high strength, we found that the packing in the packing, has the following disadvantages: the filler surface roughness, friction coefficient, leakage, and long time immersed in the lubricant used to drain。 The new fixed equipment running in good condition when the shaft seal, but before long, the leakage will increase, the adjustment and replacement of packing gland work gradually frequently, running to a cycle, Bush had been worn into the vase shape, there will be serious wear sleeve off, and the back seal ring is not changed the packing is rotten, can not play a role in sealing。 (3) the direct contact between the packing and the shaft, and the relative rotation, causes the wear of the shaft and the shaft sleeve, so it is necessary to replace the shafts regularly or unregularly。 (4) in order to make the friction heat produced by the disc root and the shaft or shaft in time dissipate, the seal must keep a certain amount of leakage, and it is not easy to control。 The friction between the disc root and the shaft or shaft sleeve causes the effective power of the motor to be reduced and the electric energy is consumed。

2.3机械密封的原理

青龙棋牌官网2。3 principle of mechanical seal

机械密封又叫端面密封,它是一种旋转机械的轴封装置,指由至少一对垂直于旋转轴线的的端面在液体压力和补偿机构弹力(或磁力)的作用以及辅助密封的配合下保持贴合并相对滑动而构成的防止流体泄漏的装置。它的主要功用将易泄漏的轴向密封改变为较难泄漏的端面密封。它广泛应用于泵、釜、压缩机及其类似设备的旋转轴的密封。机械密封通常由动环、静环、压紧元件和密封元件组成。其中动环随泵轴一起旋转,动环和静环紧密贴合组成密封面,以防止介质泄漏。动环靠密封室中液体的压力使其端面压紧在静环端面上,并在两环端面上产生适当的比压和保持一层极薄的液体膜而达到密封的目的。压紧元件产生压力,可使泵在不运转状态下,也保持端面贴合,保证密封介质不外漏,并防止杂质进入密封端面。密封元件起密封动环与轴的间隙、静环与压盖的间隙的作用,同时弹性元件对泵的振动、冲击起缓冲作用。机械密封在实际运行中是与泵的其它零部件一起组合起来运行的,机械密封的正常运行与它的自身性能、外部条件都有很大的关系。但是我们要首先保证自身的零件性能、辅助密封装置和安装的技术要求,使机械密封发挥它应有的作用。

青龙棋牌官网The mechanical seal is also called the seal, it is the seal device of a rotating machine, which consists of a pair of end faces perpendicular to the axis of rotation in the liquid pressure and the elasticity of compensation organizations (or magnetic) device and the role of the coordination of auxiliary seals to keep up with the relative sliding to prevent fluid leakage. Its main function changes the leakage of the axial seal to the face seal which is difficult to leak. It is widely used in the seal of the rotating shaft of the pump, the kettle, the compressor and the similar equipment. Mechanical seals are usually made up of a moving ring, a static ring, a compacting element and a sealing element. The movable ring is rotated with the pump shaft, and the dynamic ring and the static ring close tightly together to make up the sealing surface to prevent the leakage of the medium. The moving ring depends on the pressure of the liquid in the sealing chamber to compress the end surface on the static ring end surface, and generate an appropriate pressure on the two ring face and maintain a thin liquid film to achieve the purpose of sealing.  The pressure is generated by the pressing element, so that the pump can also keep the end face fit under the condition of no operation, ensuring that the sealing medium is not leaking, and prevents impurities from entering the sealing face. The sealing element plays the role of sealing the gap between the ring and the shaft, the gap between the static ring and the cap, and the elastic element cushioning the vibration and impact of the pump. Mechanical seals are combined with other components of the pump in actual operation. The normal operation of mechanical seals is closely related to their own performance and external conditions. But we must first guarantee the performance of its own parts, the auxiliary sealing device and the technical requirements of the installation, so that the mechanical seal should play its due role.

2.4机械密封在工业泵使用中存在的问题

2.4 problems in the use of mechanical seals in the use of industrial pumps

机械密封的零件的故障旋转设备在运行当中,密封端面经常会出现磨损、热裂、变形、破损等情况,弹簧用久了也会松弛、断裂和腐蚀。辅助密封圈也会出现裂口、扭曲和变形、破裂等情况。

Mechanical seal parts failure rotating equipment in operation, often face wear, hot cracking, deformation, damage and other conditions. Spring for a long time will also relax, fracture and corrosion. The auxiliary sealing ring also appears crack, distortion and deformation, rupture and so on.


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