• 活塞式制冷压缩机耗油过高有哪些原因?该怎么办?
  • 本站编辑:杭州谷轮制冷设备有限公司发布日期:2019-06-22 17:29 浏览次数:

压缩机是高速运转的复杂机器,保证压缩机曲轴、轴承、连杆、活塞等运动件的充分润滑是维持机器正常运转的基本要求。为此,压缩机制造商要求使用指定牌号润滑油,并要求定期检查润滑油油位和颜色。然而,由于制冷系统设计、施工和维护方面的疏忽,压缩机缺油、油焦化变质、回液稀释、制冷剂冲刷、使用劣质润滑油等造成运动件润滑不足的情况比较常见。润滑不足会引起轴承面磨损或划伤,严重时会造成抱轴、活塞卡在气缸内以及由此而引起的连杆弯曲、断裂事故。


Compressor is a complex machine running at high speed. Ensuring full lubrication of crankshaft, bearing, connecting rod, piston and other moving parts of compressor is the basic requirement to maintain the normal operation of the machine. To this end, compressor manufacturers require the use of specified brand lubricants, and require regular inspection of lubricant oil level and color. However, due to the negligence of refrigeration system design, construction and maintenance, the insufficient lubrication of moving parts caused by oil shortage, oil coking deterioration, fluid dilution, refrigerant scouring, and the use of inferior lubricants are quite common. Insufficient lubrication will lead to wear or scratch of bearing surface, and serious accidents of axle holding, piston clamping in cylinder and connecting rod bending and fracture will occur.




一、润滑不足


I. Insufficient lubrication




磨损的直接原因:润滑不足。缺油肯定会引起润滑不足,但油润不足不一定就是缺油引起的。以下三种原因也可以造成润滑不足:润滑油无法到达轴承表面;润滑油虽已到达轴承表面,但是粘度太小,不能形成足够厚度的油膜;润滑油虽已到达轴承表面,但是由于过热而分解掉了,不能起到润滑作用。


The direct cause of wear: insufficient lubrication. Deficiency of oil will certainly lead to insufficient lubrication, but insufficient lubrication is not necessarily caused by lack of oil. The following three reasons can also cause insufficient lubrication: the lubricant can not reach the bearing surface; although the lubricant has reached the bearing surface, but the viscosity is too small to form a sufficient thickness of oil film; although the lubricant has reached the bearing surface, but because of overheating and decomposition, it can not play a lubricating role.




导致的不良影响:吸油网或供油管路堵塞、油泵故障等均会影响润滑油的输送,润滑油无法到达远离油泵的摩擦面。吸油网和油泵正常,但轴承磨损、间隙过大等造成漏油和油压过低,会使远离油泵的摩擦面得不到润滑油,造成磨损和划伤。由于种种原因(包括压缩机启动阶段)没有得到润滑油的摩擦面温度会迅速攀升,超过175°C后润滑油就开始分解。“润滑不足-摩擦-表面高温-油分解”是一个典型的恶性循环,许多恶性事故包括连杆抱轴、活塞卡缸都与这个恶性循环有关。润滑不足和缺油现象可以在拆开的压缩机中看到。缺油一般表现为大面积、比较均匀的表面损伤和高温,而润滑不足更多的是在一些特定部位的磨损、划伤和高温,如远离油泵的轴承面等。


Adverse effects: blockage of oil suction network or oil supply pipeline, oil pump failure and so on will affect the delivery of lubricating oil, lubricating oil can not reach the friction surface far from the oil pump. Oil suction net and oil pump are normal, but bearing wear and clearance are too large to cause oil leakage and oil pressure is too low, which will make the friction surface far away from the oil pump can not get lubricant, resulting in wear and scratch. For various reasons (including the start-up stage of the compressor), the temperature of the friction surface without lubricating oil will rise rapidly, and the lubricating oil will begin to decompose after the temperature exceeds 175 degree C. "Insufficient lubrication - friction - surface high temperature - oil decomposition" is a typical vicious cycle, many malignant accidents including connecting rod holding axle, piston jam are related to this vicious cycle. Insufficient lubrication and oil shortage can be seen in the dismantled compressor. Oil shortage is generally characterized by large area, relatively uniform surface damage and high temperature, while insufficient lubrication is more likely to be caused by wear, scratch and high temperature in some specific parts, such as bearing surface far away from the oil pump.




活塞上下运动时,活塞销的负载是在轴承表面的上部和下部之间轮换的,这可以让润滑油均匀地刷过活塞销,并提供足够的润滑。如果排气阀片弯曲或者折断,或者压缩机长期高压比工作,将造成活塞销单侧润滑不足和磨损,孔隙增大。活塞销有晃动间隙,活塞就会在上止点处被抛出并撞击阀片和阀板,产生撞击声。因此,更换阀片时,应检查活塞销磨损情况。


When the piston moves up and down, the load of the piston pin rotates between the upper and lower parts of the bearing surface, which allows the lubricant to brush the piston pin evenly and provides sufficient lubrication. If the exhaust valve sheet is bent or broken, or the compressor works at high pressure ratio for a long time, it will cause insufficient lubrication and wear on one side of the piston pin, and increase the porosity. When the piston pin has a swing clearance, the piston will be thrown out at the top dead center and hit the valve disc and disc, resulting in an impact sound. Therefore, when replacing the valve disc, the wear of the piston pin should be checked.

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二、缺油


2. Oil shortage




缺油是很容易辨别的压缩机故障之一,压缩机缺油时曲轴箱中油量很少甚至没有润滑油。


Oil shortage is one of the compressor faults that can be easily identified. When the compressor is short of oil, there is little or no oil in the crankcase.




排出压缩机的润滑油不回来,压缩机就会缺油。压缩机回油有两种方式,一种是油分离器回油,另一种是回气管回油。油分离器安装在压缩机排气管路上,一般能分离出50-95%的奔油,回油效果好,速度快,大大减少进入系统管路的油量,从而有效延长了无回油运转时间。管路特别长的冷库制冷系统、满液式制冰系统以及温度很低的冻干设备等,开机后十几分钟甚至几十分钟不回油或回油量非常少的情况并不稀奇,设计不好的系统会出现压缩机油压过低而停机的问题。这种制冷系统安装高效油分离器能大大延长压缩机无回油运转时间,使压缩机安全度过开机后无回油的危机阶段。


If the oil discharged from the compressor does not return, the compressor will be short of oil. There are two ways to return oil to compressor, one is to return oil to oil separator, the other is to return oil to air pipe. Oil separator installed in the compressor exhaust pipeline, can generally separate 50-95% of the running oil, oil return effect is good, fast, greatly reduce the amount of oil into the system pipeline, thereby effectively prolonging the no-return operation time. It is not uncommon for refrigeration systems with long pipelines, full-liquid ice-making systems and freeze-drying equipment with very low temperature not to return oil or very little oil in ten minutes or even tens of minutes after start-up. The problem that compressor oil pressure is too low and shutdown will occur in poorly designed systems. The installation of high efficiency oil separator in this refrigeration system can greatly prolong the running time of the compressor without oil return, and make the compressor safely pass through the crisis stage of no oil return after start-up.




未被分离出来的润滑油将进入系统,随制冷剂在管内流动,形成油循环。润滑油进入蒸发器后,一方面因温度低溶解度小,一部分润滑油从制冷剂中分离出来;另一方面,温度低粘度大,分离出来的润滑油容易附着在管内壁上,流动比较困难。蒸发温度越低,回油越困难。这就要求蒸发管路设计和回气管路设计和施工必须有利于回油,常见的做法是采用下降式管路设计,并保证较大的气流速度。对于温度特别低的制冷系统,如-85°C和-150°C医用低温箱,除选用高效油分离器外,通常还添加特殊溶剂,防止润滑油堵毛细管和膨胀阀,并帮助回油。


Unseparated lubricants will enter the system and flow with refrigerant in the tube, forming an oil cycle. When lubricating oil enters the evaporator, on the one hand, because of the low temperature and low solubility, some lubricating oil is separated from the refrigerant; on the other hand, because of the high temperature and low viscosity, the separated lubricating oil is easy to adhere to the inner wall of the tube and the flow is difficult. The lower the evaporation temperature is, the more difficult it is to return oil. This requires that the design and construction of evaporation pipeline and return gas pipeline must be conducive to oil return. The common method is to adopt descending pipeline design and ensure a larger air flow rate. For refrigeration systems with extremely low temperatures, such as - 85 C and - 150 C medical cryogenic chambers, in addition to the selection of high-efficiency oil separators, special solvents are usually added to prevent lubricating oil from blocking capillaries and expansion valves, and to help return oil.




实际应用中,由于蒸发器和回气管路设计不当引起的回油问题并不罕见。对于R22和R404A系统来说,满液式蒸发器的回油非常困难,系统回油管路设计必须非常小心。对于这样的系统,使用高效油分可以大大减小进入系统管路的油量,有效延长开机后回气管无回油时间。当压缩机比蒸发器的位置高时,垂直回气管上的回油弯是必需的。回油弯要尽可能紧凑,以减小存油。回油弯之间的间距要合适,回油弯的数量比较多时,应该补充一些润滑油。变负荷系统的回油管路也必须小心。当负荷减小时,回气速度会降低,速度太低不利于回油。为了保证低负荷下的回油,垂直的吸气管可以采用双立管。


In practical application, the problem of oil return caused by improper design of evaporator and return pipeline is not rare. For R22 and R404A systems, it is very difficult to return oil to full-liquid evaporator, and the design of return pipeline must be very careful. For such a system, the use of high-efficiency oil can greatly reduce the amount of oil entering the system pipeline, effectively prolong the no-return time of the return pipe after the start-up. When the position of the compressor is higher than that of the evaporator, the oil return bend on the vertical return pipe is necessary. The return bend should be as compact as possible to reduce oil storage. The spacing between oil return bends should be appropriate. When the number of oil return bends is large, some lubricants should be added. Care must also be taken in the return pipeline of the variable load system. When the load decreases, the return air speed will decrease, too low is not conducive to return oil. In order to ensure oil return under low load, double risers can be used in vertical suction pipes.




压缩机频繁启动不利于回油。由于连续运转时间很短压缩机就停了,回气管内来不及形成稳定的高速气流,润滑油就只能留在管


Frequent start-up of compressor is not conducive to oil return. Because the compressor stops running for a very short time, there is no time to form a stable high-speed air flow in the return pipe, so the lubricant can only be left in the pipe.