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新聞動(dòng)態(tài)
水泵密封的原理及要求
2018-01-18 10:17
1填料密封的原理
The principle of 1 packing seal
在機(jī)械行業(yè)中填料密封主要用作動(dòng)密封，常用作離心泵、壓縮機(jī)、真空泵、攪拌機(jī)的轉(zhuǎn)軸密封。填料裝入填料腔以后，經(jīng)壓蓋螺絲對(duì)它作軸向壓縮，當(dāng)軸與填料有相對(duì)運(yùn)動(dòng)時(shí)，由于填料的塑性，使它產(chǎn)生徑向力，并與軸緊密接觸。與此同時(shí)，填料中浸漬的潤(rùn)滑劑被擠出，在接觸面之間形成油膜。由于接觸狀態(tài)并不是特別均勻的，接觸部位便出現(xiàn)“邊界潤(rùn)滑”狀態(tài)，稱為“軸承效應(yīng)”；而未接觸的凹部形成小油槽，有較厚的油膜，接觸部位與非接觸部位組成一道不規(guī)則的迷宮，起阻止液流泄漏的作用，此稱“迷宮效應(yīng)”。這就是填料密封的機(jī)理。良好的密封在于維持“軸承效應(yīng)”和“迷宮效應(yīng)”。也就是說(shuō)，要保持良好的潤(rùn)滑和適當(dāng)?shù)膲壕o。若潤(rùn)滑不良，或壓得過(guò)緊都會(huì)使油膜中斷，造成填料與軸之間出現(xiàn)干摩擦，比較后導(dǎo)致燒軸和出現(xiàn)嚴(yán)重磨損。因此，我們需要經(jīng)常對(duì)填料的壓緊程度進(jìn)行調(diào)節(jié)，使填料中的潤(rùn)滑劑在運(yùn)行一段時(shí)間而有所流失之后，再擠出一些潤(rùn)滑劑，同時(shí)補(bǔ)償填料因體積變化所造成的壓緊力松弛。當(dāng)然這樣經(jīng)常擠壓填料，比較后將使浸漬劑枯竭，所以定期更換填料是必要的。此外，為了維持液膜和帶走摩擦熱，有意讓填料處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填料密封在工業(yè)泵使用中存在的問(wèn)題
Problems in the use of 2.2 packing seal in the use of industrial pumps
工業(yè)泵的軸封一般采用具有耐磨性、耐熱性、柔軟性好、強(qiáng)度高等優(yōu)點(diǎn)，我們?cè)谟帽P根填料，發(fā)現(xiàn)其具以下個(gè)缺點(diǎn):①填料表面粗糙、摩擦系數(shù)大、有滲漏現(xiàn)象，另外使用久了浸入的潤(rùn)滑劑容易流失。②新修好的設(shè)備，開(kāi)始運(yùn)行時(shí)軸封狀況良好，但用不了多久，泄漏量便不斷增加，調(diào)整壓蓋和更換填料的工作也逐漸頻繁，運(yùn)轉(zhuǎn)不到一個(gè)周期，軸套就已磨損成花瓶狀，嚴(yán)重時(shí)還會(huì)出現(xiàn)軸套磨斷，并且水封環(huán)后面更換不到的盤根填料均已腐爛，無(wú)法起到密封作用。③填料與軸直接接觸，且相對(duì)轉(zhuǎn)動(dòng)，造成軸與軸套的磨損，所以必須定期或不定期更換軸套。④為了使盤根與軸或軸套間產(chǎn)生的摩擦熱及時(shí)散掉，盤根密封必須保持一定量的泄漏，而且不易控制。⑤盤根與軸或軸套間的摩擦，造成電機(jī)有效功率降低，消耗電能。
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機(jī)械密封的原理
2.3 principle of mechanical seal
機(jī)械密封又叫端面密封，它是一種旋轉(zhuǎn)機(jī)械的軸封裝置，指由至少一對(duì)垂直于旋轉(zhuǎn)軸線的的端面在液體壓力和補(bǔ)償機(jī)構(gòu)彈力(或磁力)的作用以及輔助密封的配合下保持貼合并相對(duì)滑動(dòng)而構(gòu)成的防止流體泄漏的裝置。它的主要功用將易泄漏的軸向密封改變?yōu)檩^難泄漏的端面密封。它廣泛應(yīng)用于泵、釜、壓縮機(jī)及其類似設(shè)備的旋轉(zhuǎn)軸的密封。機(jī)械密封通常由動(dòng)環(huán)、靜環(huán)、壓緊元件和密封元件組成。其中動(dòng)環(huán)隨泵軸一起旋轉(zhuǎn)，動(dòng)環(huán)和靜環(huán)緊密貼合組成密封面，以防止介質(zhì)泄漏。動(dòng)環(huán)靠密封室中液體的壓力使其端面壓緊在靜環(huán)端面上，并在兩環(huán)端面上產(chǎn)生適當(dāng)?shù)谋葔汉捅３忠粚訕O薄的液體膜而達(dá)到密封的目的。壓緊元件產(chǎn)生壓力，可使泵在不運(yùn)轉(zhuǎn)狀態(tài)下，也保持端面貼合，保證密封介質(zhì)不外漏，并防止雜質(zhì)進(jìn)入密封端面。密封元件起密封動(dòng)環(huán)與軸的間隙、靜環(huán)與壓蓋的間隙的作用，同時(shí)彈性元件對(duì)泵的振動(dòng)、沖擊起緩沖作用。機(jī)械密封在實(shí)際運(yùn)行中是與泵的其它零部件一起組合起來(lái)運(yùn)行的，機(jī)械密封的正常運(yùn)行與它的自身性能、外部條件都有很大的關(guān)系。但是我們要保證自身的零件性能、輔助密封裝置和安裝的技術(shù)要求，使機(jī)械密封發(fā)揮它應(yīng)有的作用。
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機(jī)械密封在工業(yè)泵使用中存在的問(wèn)題
2.4 problems in the use of mechanical seals in the use of industrial pumps
機(jī)械密封的零件的故障旋轉(zhuǎn)設(shè)備在運(yùn)行當(dāng)中，密封端面經(jīng)常會(huì)出現(xiàn)磨損、熱裂、變形、破損等情況，彈簧用久了也會(huì)松弛、斷裂和腐蝕。輔助密封圈也會(huì)出現(xiàn)裂口、扭曲和變形、破裂等情況。
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.
