1、干气密封系统遭受油污染原因的分析及措施摘要：干气密封受到润滑油的污染后极易损坏，即使按照干气密封的使用说明操作也未必能避免此情况出现，本文就其可能的原因进行了分析并提出了相应的保护措施。关键词：干气密封、污染、润滑油中图分类号： TH136 文献标识码：BAbstract：The dry gas seal can be damaged easily as be polluted by lube oil. The case could not be avoided completely even when you refer to the instruction. Why？Here is som
2、e possibility and protective measures that are suggested in order to discuss together.Keyword：dry gas seal, pollution, lube oil 引言0 the introduction 干气密封是一种新型的无接触轴封，由它来密封旋转机械中的气体或液体介质。与其它密封相比，干气密封具有泄漏量少，磨损小，寿命长，能耗低，操作简单可靠，维修量低，被密封的流体不受油污染等特点。因此，在压缩机应用领域，干气密封正逐渐替代浮环密封、迷宫密封和油润滑机械密封。干气密封使用的可靠性和http:/ h
3、ttp:/ gas seal is a new kind of non-contact seal, sealing of rotating machinery by which a gas or liquid medium. Compared with the other seal, dry gas seal has the advantages of low leakage, wear small, long life, low energy consumption, simple and reliable operation, low maintenance, sealed fluid i
4、s not polluted by oil, etc. Dry gas seal in compressor applications, therefore, is gradually instead of floating ring seal and labyrinth seal and lubrication of mechanical seals. Dry gas seal used in reliability and economical efficiency has been confirmed by many engineering applications. But once
5、the dry gas seal itself polluted by oil, easily damaged, so how to protect the dry gas seal oil pollution becomes significant. 1 干气密封的工作原理1, the working principle of dry gas seal 干气密封和普通平衡型机械密封相似，也由静环和动环组成，其中：静环由弹簧加载，并靠 O 型圈辅助密封。端面材料可采用碳http:/ http:/ gas seal and ordinary the balance type mechanical
6、 seal are similar, and is composed of static ring and ring, including: static ring by a spring loaded, and the auxiliary seal o-rings. End face material can use silicon carbide, silicon nitride, carbide and graphite. Dry gas seal ring face gas tank, gas tank depth of only a few microns, between the
7、end face must have a clean gas and dry gas seal to ensure the work between the two end surface to form a stable gas film seal face completely separated. Gas film thickness is usually a few microns, the stability of the gas film will keep the seals between the seal clearance. Gas medium through the s
8、eal clearance by throttling and blocked by decompression effect, so as to realize the sealing of gas medium, a few microns of the seal clearance to keep gas leakage rate to a minimum. http:/ http:/ The performance of fault after by the oil pollution and consequences 当干气密封动静环断面之间有油存在时，油就会在动静环之间形成一层几微
9、米厚的油膜，这层油膜使动环端面上的气槽丧失吸入气体的工作能力。但这还不足以造成机内介质气体的外泄，因为有油膜阻碍了气体。真正的原因在于动静环之间摩擦产生的热量被中间的油膜吸收，但是并没有散热的地方，持续升温导致动静环由于过热产生脆裂，最终使干气密封报废。http:/ http:/ the dry gas seal of dynamic and static ring cross section between the presence of oil, the oil will be in of dynamic and static ring formed between a few micro
10、ns thick layer of oil film, the layer of oil film made the gas tank on the ring end face loss of suction gas work ability. But this was not enough to cause internal medium gas leak, because of the oil film hindered the gas. The real reason lies in the movement of heat generated by the friction betwe
11、en the ring was in the middle of the oil film to absorb, but there is no cooling, growing cause of dynamic and static ring due to overheating embrittlement, eventually make the dry gas seal scrap. .原因分析3. Root cause analysis 干气密封位于轴端密封与支撑轴承之间，内可防止介质气体外漏，外可起到隔离润滑油的作用。主要靠的是干气密封前端的带有隔离气梳齿密封来隔离润滑油的（见图 2
12、） 。Located at the shaft end seal and dry gas seal support between the bearing and can prevent gas leakage of medium, can have the effect of isolation of lubricating oil. Mainly by the front end of the dry gas seal is a isolated gas comb teeth seal to lubricating oil (see chart 2). http:/ http:/ 20kP
13、a 左右。隔离气需要在主油泵开启之前提供，停车后待高位油箱里的油排净后方可关闭。如果未能及时投用隔离气，或中途隔离气停供，就可能出现油进入干气密封的情况。因此在现场操作中，必须要严格按照该步骤进行。Under normal circumstances, after the orifice throttling isolation gas passes through the speed of sound pressure control around 20 kpa. Isolated gas need to provide before, the main oil pump is opened
14、 after parking stay high fuel tank of oil in the row behind the net can be closed. If you failed to timely putting-in-service proactively isolation air, or isolation, stop for gas, oil into dry gas seal is likely to happen. So in site operation, must be in strict accordance with the steps. http:/ ht
15、tp:/ event of oil pollution in the dry gas seal and dry gas seal is usually improper operation or the outer o-ring seal damage or sealing area as the level of subdivision and the joint surface caused by lax, these reasons can be avoid correct operation or a change of aprons. But sometimes in the ste
16、ps the right cases, possible oil into dry gas seal. 以一个现场为例，操作工曾经在一级密封气放火炬的管道里发现了油迹，并确定就是设备的润滑油。后来设备检修时检查干气密封最外圈的密封圈，全部完好并且没有油渗透的迹象，在梳齿密封内部明显有一层油。该风机为筒型压缩机，不存在中分面不严的可能。启车与停车步骤均按照操作规程进行，隔离气（氮气）气源稳定。干气密封厂家服务人员分析，唯一的可能性就是油通过梳齿密封沿着黑线的路径进入到放火炬孔内（图 2 黑线所示路径） 。也就是说隔离气密封失去了隔离油的作用。In a field as an example, t
17、he operator had put the torch in primary sealing http:/ http:/ pipe found in soil, and determined the equipment lubricating oil. Later in the dry gas seal equipment inspection maintenance of sealing ring, all intact and show no signs of oil penetration, there was an obvious layer inside the comb tee
18、th seal oil. This fan for cylinder type compressor, there is no split is lax. Rev. Car parking steps are carried out in accordance with the operating rules, and isolate the gas (n2) gas source is stable. Dry gas seal manufacturer service analysis, the only possibility is the oil through the comb tee
19、th seal along the path put the torch into the hole of the black line (as shown in figure 2 black line path). That is isolated gas seal lost oil. 那么是什么原因造成隔离气正常投用的情况下依旧封不住油的呢？在扩大排查范围之后，发现该侧润滑油压力为 0.16Mpa，高于正常使用范围 0.090.13MPa。排污阀排放频率较低，大约 12 个月排污一次，并且每次排放均能发现一定量的油排出。由此推测润滑油压过高，油的流量大，不断冲刷着干气密封外侧第一道轴肩处，
20、就会有一部分油顺着轴下方流淌到隔离气梳齿密封附近。回油量的增加使回油液位有了一定的提升，波动的液位在最高值时甚至高过了梳齿密封最下端的密封齿。虽然有隔离气存在，但是梳齿密封下方存在的油的阻力使气体并非均匀的沿着密封间隙向外流，而是倾向于阻力较小的上方空隙，从而产生上面排气下面进油的情况。油漫过梳齿密封后就到了二次密封气放空和排污的空腔内，加之排污http:/ http:/ causes the isolation air still cannot seal oil under the condition of normal putting-in-service proactively? Aft
21、er expanding the scope of the screen, found that the lube oil pressure is 0.16 Mpa, higher than the normal range 0.09 0.13 Mpa. Drain valve discharge frequency is low, about 1 2 month drainage time, and each discharge can find out a certain amount of oil. Thus speculated that lube oil pressure is to
22、o high, the oil flow is large, constantly scour the dry gas seal outside of the first shoulder, there will be a part of the oil that flows along the shaft under the gas insulation comb teeth near the seal. Back to the increase in oil had the certain promotion back to the oil, the fluctuation of the
23、liquid level in high and even higher than when the comb teeth seal the bottom seal. Although there are isolated gas exists, but below the comb teeth seal oil resistance of gas is not uniform along the seal clearance to outflows, but tend to be above the resistance smaller gap, to produce exhaust inl
24、et under the above conditions. Oil overflow the comb teeth seal arrived after http:/ http:/ second seal gas within the cavity of vent and drain, combined with the drain valve discharge frequency or interval cant timely discharge the oil will flow to the oil and effortlessly along the gap between the
25、 stator components into the secondary seal gas movement ring inside the cavity. Part of oil from the static ring back spring area to put the torch in the ring groove, another part of the oil under the effect of rotating centrifugal force produced by the, the static ring joint surface permeability to
26、 put the torch in the ring groove. Outward from primary and secondary seal gas emissions, then the oil to put the torch inside the pipe. 另外二级密封气放空管阻力的大小和轴承区放空管阻力的大小可能也是造成隔离气封不住油的一个原因。若二级密封气放空管阻力小而轴承区放空管阻力大，一旦轴承区内压力大于放空腔内的压力，那么隔离气更多的是朝向阻力小的一侧流动，从而减少了起到隔离油作用的气量。Other secondary seal gas vent pipe the s
27、ize of the resistance and the bearing area the size of the vent pipe resistance may also be one of the reasons that cause can not isolate the air seal oil. If the secondary seal gas vent pipe small resistance and large bearing area blow-down pipe resistance, once the pressure is greater than empty c
28、avity pressure bearing area, then isolate gas more toward small resistance on one side of the http:/ http:/ thus reducing the gas oil isolation effect. .解决措施4. The solution measures 要想从根本上解决干气密封遭受油污染的问题，需要从操作和维护两方面入手。To fundamentally solve the dry gas seal of oil pollution problems, need from the tw
29、o aspects of operation and maintenance. 在操作上，第一要调节支撑轴承润滑油支管的供油压力，只要能满足轴承温度要求，尽量降低油压，降低油从阻油环中泄油的流量。第二要经常性地打开排污阀，检查内部是否有油。第三要确保轴承区内气压不至造成隔离气受阻，能直排的直排到厂房里，有防爆要求的则要尽量减少管道的阻力元件，必要时接排风机。In operation, the first to adjust the support bearing lubricating oil pipe of oil supply pressure, as long as can satisf
30、y the requirement of bearing temperature, lower oil pressure, as far as possible to reduce the flow of oil spill from the resistance ring. Second to regularly open the drain valve http:/ http:/ check internally whether there is oil. 3 make sure that the pressure bearing area will not cause isolation
31、 air, straight row of straight line to the factories, with explosion-proof requirements is to reduce pipeline resistance components, necessary exhaust fan. 在维护上，每次检修时要对干气密封内外圈胶圈进行更换，检查梳齿密封齿顶是否磨损，有磨损要及时更换备件，保证密封间隙。清理干气密封表面，不得有油渍存在。从干气密封控制盘到密封环槽之间的管路都要确保清洁，可能的情况下进气管要脱油处理。及时更换进气过滤器。Every time on mainte
32、nance, repair of dry gas seal change both inside and outside circle aprons, check the comb tooth addendum for wear and seal have wear to timely replacement of spare parts, ensure the seal clearance. Clear the surface of dry gas seal, oil stains may not exist. From the control panel to the gasket groove dry gas seal between the pipe to ensure clean, possible inlet pipe to deoiling treatment. Promptly replace the air intake filter.
