化工英文文献翻译

Three Common Details of The Compressor Failure Analysis

Compressor Fault Analysis (1) - motor burned

Motor compressor (hereinafter referred to as the compressor) of the fault can be divided into motor failure and mechanical failure (including the crankshaft, connecting rod, piston, valve, cylinder head pad, etc.). Mechanical failure is often the motor overload or stall, is one of the main motor damage.

Damage mainly to the motor stator winding insulation damage (short circuit) and the circuit and so on. Stator windings was found damaged hard time, could eventually lead to winding burned. Winding burned, cover up some cause or direct cause of the phenomenon of burning, making the subsequent analysis and cause investigation more difficult.

However, the operation of the motor power input is inseparable from the normal, reasonable motor load, good heat dissipation and winding wire insulation layer of protection. From several aspects, not difficult to find reason than burnt windings are six: (1) abnormal load and stall; (2) Winding short circuit caused by metal shavings; (3) contactor problems; (4) Power phase and voltage abnormalities; (5) inadequate cooling; (6) compressor vacuum. In fact, many factors contributed to the more common motor damage.

1. Abnormal loads and stall

Motor load requirements, including compressed gas load and the load required to overcome mechanical friction. Pressure ratio is too large, or the pressure is too large, the compression process will be more difficult; and increased friction caused by lubrication failure, and extreme cases of motor stall, will greatly increase the electrical load. Lubrication failure, friction increases, is the leading cause of abnormal load. Back to the diluted lubricating oil, oil heat, oil coking deterioration and lack of oil and so will disrupt normal lubrication, leading to lubrication failure. Back to the diluted lubricating oil, affecting the normal friction surface film formation, or even washed away the original film, increasing friction and wear. Compressor overheating will cause the thinning or even high-temperature coking oil, affecting the normal film formation. System back to the oil well, the compressor short of oil, they can not maintain normal lubrication. High-speed rotating crankshaft, connecting rod piston speed movement, there is no friction surface protection film will quickly heat up, local high-temperature rapid evaporation of the oil or coke, to make it more difficult to lubricate the parts, a few seconds can cause severe localized wear. Lubrication failure, local wear, the need for greater torque to the crankshaft. Low-power compressor (such as refrigerators, home air conditioning compressor) as the motor torque, lubrication failure often occurs after the stall (the motor can not rotate) phenomenon, and enter the "stall - Thermal protection - Locked" death cycle, motor burn only a matter of time. The high-power semi-closed compressor motor torque large, local wear will not cause stall, the motor power will be within a certain range increases with the load, causing more serious wear and tear, and even lead to bite cylinder (live seca in cylinder), rod fracture and other serious damage.

When the current stall (stall current) is about 4-8 times the normal running current. The moment of starting the motor, the current reached a peak close to or stall current.

Because the resistance heat release proportional to the square with the current, start and stall when the winding current will heat up quickly. Thermal protection can protect the electrode in the stall, but generally will not have a response soon, can not prevent such frequent starting winding due to temperature changes. Frequent starts and abnormal load, so that the test winding subjected to high temperature will reduce the magnet wire insulation.

In addition, the compressed gas with the compression ratio will be required to increase the load and pressure increases. Therefore, the high temperature compressor for low temperature, or low compressor for high temperature, will affect the electrical load and heat, is not appropriate, will shorten the electrode life.

Winding insulation deterioration, if there are other factors (such as metal shavings form conductive loops, acid oil, etc.) with, it is easy to cause a short circuit and damage.

2. Scrap metal caused by short circuit

Winding metal particles are mixed and ground insulation value of the low short-circuit the culprit. The normal vibration of the compressor running, and every time you start winding by the magnetic force of the pipe, will promote inclusion in the winding and the winding metal shavings between the relative motion between the magnet wire and friction. Sharp edges will scratch the enameled metal shavings insulation, causing short circuits. Sources including the construction of metal debris left behind by the brass shavings, welding slag, compressor internal parts wear and damage (such as broken valves), the fall of the metal shavings and so on. For the closed compressor (including the closed scroll compressor), the metal shavings or broken, would fall on the winding. For semi-hermetic compressors, and some particles with the gas and oil flow in the system, and finally assembled in the magnetic winding; and some metal shavings (such as bearing wear and stator and rotor wear (sweep bore) is generated) will be directly on the winding. Winding metal shavings gathered after a short circuit is only a matter of time.

Need to draw particular attention to the two-stage compressor. In the two-stage compressor, back to the normal gas and oil directly back into the first grade (low grade) cylinder, compressed by the pressure of the cooling tube into the motor winding cavity, and the general single-stage compressor and then as second-class (high pressure stage cylinder.) Back to the gas with oil, the compression process has been skating on thin ice, if there are back to liquid again, the first stage cylinder valve can easily be broken. Broken by the pressure valve can enter the winding tube. Therefore, the two-stage compressor than the single-stage compressors are more likely to electrical short circuit caused by metal shavings.

Unfortunately, things tend to conspire a piece of the compressor in the boot of a problem when the news channels is often the oil burning. Severe wear of metal surfaces when the temperature is very high, while oil above 175 o C at the start of coking. System, if there is more moisture (vacuum pits not ideal, big oil and refrigerant water, negative pressure air into the return pipe burst, etc.), lubricants acid may occur. Acidic oil will corrode copper and winding insulation layer, on the one hand, it can cause copper plating phenomenon; on the other hand, this acid containing copper atoms very poor insulation properties of lubricating oil, provided the conditions for the winding circuit.

3. Contactor problem

Contacts is an important component in the motor control circuit, one of the best selection of irrational destruction of the compressor can be. The right choice according to the load contacts are extremely important.

Contactor must be able to meet the harsh conditions, such as rapid cycling, continuous overload and low voltage. They must have enough surface area to distribute the heat generated by the load current, contact material should be selected to start or stall in such circumstances to prevent high current welding.

For safe and reliable, while the compressor contactor to disconnect the three-phase circuit. Copeland is not recommended way to disconnect the two-phase circuits.

In the United States, Copeland approved contactor must meet the following four:

? contactor must meet ARI Standard 780-78, "Standard for special access" provisions of the work and testing guidelines.

? The manufacturer must ensure that the contacts at room temperature in the lowe st 80% of nameplate voltage can be closed.

? When using a single contactor, the contactor must be greater than the motor nameplate rated current rating (RLA). Meanwhile, the contactor must be able to withstand motor stall current. If there are other loads downstream of the contactor, such as electrical fans, and so must also be considered.

? When using two contactors, each contactor rating of the sub-winding stall must be equal to or greater than the rating of the compressor stall half-winding.

Contacts can not be less than the rated current of the compressor nameplate rated current. Size small or poor quality of contact can not withstand the compressor starts, stall, and low voltage high current impact, single-phase or multiphase prone to contact bounce, the phenomenon of welding or even fall off, causing electrical damage.

Contact jitter frequently start and stop the motor contactor. Frequent motor starts, a huge starting current and heat, will aggravate the winding insulation aging. Each time you start, the magnetic torque to the motor windings have small mobile and mutual friction. If there are other factors with (such as metal shavings, poor insulation oil, etc.) can easily lead to short circuits between windings. Thermal protection system is not designed to prevent such damage. In addition, the jitter of the contactor coil easy to failure. If you have contact with the coil is damaged, prone to single-phase state.

If the small selection of the contactor, the contact arc, and can not afford to open due to the frequent instability of circulatory arrest or heat generated by the voltage control loop may be welded together or from the contact frame in the loss. Welding of the contacts will have a permanent single-phase state, the overload protection device continuously cycle on and off.

Needs to be stressed is that after the welding contactor, disconnect the compressor contactor power dependence of all the control loop (such as high and low pressure control, hydraulic control, defrost control, etc.) will all fail, the compressor is unprotected state. Therefore, when the motor burned, check the contacts are essential processes. Contacts lead to motor damage is often forgotten as a major reason.

Compressor Fault Analysis (2) - liquid strike

1. Processes and phenomena

(1) suction valves are breaking

Compressed gas compressor is a machine. Typically, compressed air piston 1450 times per minute (half-closed compressor), or 2900 times (all closed compressor), a suction or exhaust to complete the process time is 0.02 seconds or less. Suction and discharge valve plate of the size of the aperture and the suction valve sheet flexibility and strength are designed in accordance with the gas flow. The force from the perspective of the valve, the gas flow impact force is relatively uniform.

The density of the liquid is dozens or even hundreds of times the gas, and thus the momentum of the liquid flow much larger than the gas, the impact force is also much larger. Mixed with more droplets aspirated into the cylinder when the flow is two-phase flow. Two-phase flow in the suction valve chip is not only the impact of high intensity and frequency, as if the typhoon beat mixed with pebbles at the window, the destructive self-evident. Is the liquid suction valve are breaking hit one of the typical characteristics and processes.

(2) rod fracture

Compression stroke of the time about 0.02 seconds, while the discharge process will be more short-lived. Or liquid droplets in the cylinder must be in such a short period of time discharged from the vent, the speed and momentum is significant. The case of exhaust valve and the suction valve sheet film the same, the difference is limited piece exhaust valve plate and spring-bit support is not easy to break. The impact of serious, limit deformation plate will tilt.

If the liquid does not evaporate and discharge time cylinder, piston near top dead center when the compressed liquid, due to a very short time, the compressed liquid the process seems to be hit, also came in the metal cylinder head knocking. Compressed liquid is a liquid hammer or another part of the process.

Instantly generate high-pressure liquid hit the broken ring of the great, the beginning of the familiar rod bending or breaking, the other pieces of compression force (valve plate, disc pads, crankshaft, piston, piston pin, etc.) will also be deformed or damage, but often overlooked, or confused with the exhaust pressure is too high. Maintenance of the compressor, people will be very easy to find bent or broken connecting rod, and give replacement, and forget to check whether there are other parts of deformed or damaged, thus laying the seeds for future failure.

Attack caused by the fracture fluid is different from the axle rod and piston cylinder bite, it can tell. First, the liquid hit causing rod bent or broken in the short span of time, the rod ends of the piston and crankshaft motion freely, and not generally cause serious wear and tear or bite cylinder axle. Despite the broken piece suction valve, the valve can cause debris occasionally serious scratch piston and cylinder surface, but scratch the surface caused by wear and lubrication failure is very different. Secondly, the liquid caused by rod fracture attack is caused by stress, the connecting rod and a compression feature off stubble. Although the bite cylinder piston rod after the squeeze is also likely to fracture, but only to be stuck in the cylinder piston. Link broken axle after more different, connecting rod and crankshaft are badly scratched, resulting in a broken force is shear stress, are not the same broken stubble. Finally, and bite-cylinder front axle, the motor overload, severe

motor heating, thermal protection will be action.

2. Reasons

Obviously, the compressor can cause the liquid fluid is nothing more than hit several sources as follows: 1) back to the fluid, which flows back to the compressor from the evaporator liquid refrigerant or lubricating oil; 2) starts with a liquid foam; 3) compressor lubricant too much. This paper will analyze each of these types of reasons.

(1) back to the liquid

Typically, back to the compressor run-time solution is the evaporator liquid refrigerant in the suction line back to the compressor through the phenomenon or process.

For the refrigeration system expansion valve, expansion valve back to liquid and is closely related to improper selection and use. Expansion valve selection is too large, too small to set superheat, temperature of installation method is not correct or damaged insulation wrap, expansion valve failure can cause back to the fluid. For a small refrigeration system using capillary, the increase will cause excessive fluid back to liquid.

Hot gas defrost system using prone to back solution. Regardless of the heat pump reversing valve operation, or by cooling hot gas bypass valve operation, hot gas defrost the evaporator after the formation of large amounts of liquid, the liquid refrigerant in the subsequent start of the run both possible and return to the compressor.

In addition, severe frost evaporator fan failure or deterioration of heat transfer, no evaporation will cause the liquid back to liquid. Cold storage temperature fluctuations can also cause frequent reaction failures caused by the expansion valve back to liquid.

Back to the liquid medium caused the accident hit mostly in air-cooled type (referred to as air-cooled or air cooled) semi-hermetic compressors and single two-stage compressors, compressor cylinders because they are directly connected with the return pipe, and once back to the fluid, easily lead to fluid strike accidents. Even if the strike did not cause fluid to return fluid into the cylinder will be diluted or washed away the wall of the piston and cylinder lubricating oil, increased piston wear.

For the return air (refrigerant vapor) cooled semi-closed and closed compressor, back to the liquid rarely cause fluid attack. But it will dilute the crankcase oil. Contains large amounts of liquid refrigerant in the oil viscosity is low, the friction surface can not form a sufficient oil film, resulting in rapid wear of moving parts. In addition, the refrigerant oil in the transport process in the case of boiling heat will affect the normal transport lubricants. The farther from the pump, the more obvious the more serious problems. If a serious motor side bearing wear, the crankshaft to the side of the settlement could easily lead to the stator and the motor burned sweep Church.

Obviously, back to the liquid solution will not only lead to strike, but also the wear of lubricating oil dilution. Wear and current load the motor will be greatly increased, over time will cause motor failure.

Difficult to avoid the return liquid cooling system, installation of gas-liquid separator and taking the time to stop using the control can prevent or reduce the harm back to liquid. (2) start with liquid

Return air-cooled compressor is started, the crankcase oil is called the phenomenon of severe blistering start with liquid. When starting with a blistering fluid in the oil sight glass can be clearly observed. Start with the root cause of liquid dissolved in oil and submerged

in the oil following a large number of the refrigerant, the pressure suddenly decreases suddenly boiling and cause blistering oil. This phenomenon is similar to our daily lives and suddenly open the coke cola bottle bubble phenomenon. The length of the duration of foaming agent into the area and cooling, usually a few minutes or ten minutes. The surface of a large number of bubbles floating in the oil, and even filled the crankcase. Once the cylinder through the suction inlet, the bubble will be reduced to liquid (a mixture of oil and refrigerant) can easily lead to fluid attack. Obviously, start with a liquid solution due to hit only occurs during the startup process.

And back to the liquid is different from cause to start with liquid refrigerant is "refrigerant migration" of the way into the crankcase. Refrigerant migration is the compressor stops running, the evaporator refrigerant in gaseous form, through the trachea way back into the oil absorbed by the compressor or condensing in the compressor oil after mixing with the process or phenomenon.

After the compressor is stopped, the temperature will decrease, and the pressure will rise. As the refrigerant vapor lubricant points down, it will absorb the oil surface of the refrigerant vapor, causing crankcase pressure lower than the evaporator pressure phenomenon. Lower oil temperature, the lower the vapor pressure of refrigerant vapor in the greater absorption of force. Evaporator to the crankcase vapor will slowly "migrate." In addition, if the compressor outside, cold weather or at night, the temperature is often lower than the indoor evaporator, the crankcase pressure there is low, the refrigerant can easily migrate to the compressor and into oil by condensation.

Refrigerant migration is a very slow process. The longer the compressor is stopped, migrated to the oil in the refrigerant with it. Exist as long as the evaporator liquid refrigerant, this process will be conducted. As the refrigerant dissolved heavy oil, it will sink to the bottom of the crankcase, and oil floating in the above can also absorb more refrigerant.

In addition to outside attack likely to cause liquid refrigerant migration will dilute the lubricating oil. Is very dilute oil pump to the friction surface, rinse out the original film may be washed, causing severe wear (a phenomenon often called refrigerant erosion). Wear transition with the gap will become larger, causing oil spills, thus affecting distant parts of the lubrication oil pressure will cause serious protection action.

Due to structural reasons, the air-cooled compressor starts reducing crankcase pressure will be much slower, not very severe blistering, the bubble is difficult to enter the cylinder, air-cooled compressor so there is no problem with liquid starting fluid attack.

In theory, the compressor crankcase heater installed (electric heater) can effectively prevent refrigerant migration. Short stop (eg at night), the crankcase heater to maintain power, the system can make the oil temperature is higher than other parts, refrigerant migration does not occur. No downtime (such as a winter), the heating oil before you start a few or ten hours, to evaporate the majority of oil in the refrigerant fluid can either start with a greatly reduced possibility of liquid strike , which also can reduce the harm caused by erosion of refrigerant. However, the actual application, the heater power to maintain after the shutdown or give ten hours before the heater power supply is difficult. Therefore, the practical effect of the crankcase heater will be greatly reduced.

For larger systems, shut down before the evaporator to the compressor pumping liquid

refrigerant (known as taking the time to stop), can fundamentally prevent refrigerant migration. The pipe on the way back to the installation of gas-liquid separator, refrigerant migration can increase the resistance and reduce migration.

Of course, by improving the compressor structure, can prevent refrigerant migration and reduce oil foaming degree. By improving the return-air-cooled compressor oil return path in the motor crankcase cavity and increased channel migration points (back pumps, etc.), you can cut off the access road after the shutdown, the refrigerant can not enter the crankshaft chamber; reduced intake Road and cross the channel to the crankcase when the crankcase pressure to slow down the boot speed, then control the degree of foaming and foam into the cylinder volume.

(3) too much oil

Semi-hermetic compressors usually have the oil sight glass to observe the oil level. Oil sight glass oil level above the range, indicating that the oil too much. Oil level is too high, high-speed rotation of the crankshaft and connecting rod may hit oil level frequently, causing a lot of splash oil. Once the oil splash fleeing into the inlet, into the cylinder, causing fluid to be hit.

Large refrigeration system installation, they often need to add the appropriate lubricant. But for the poor oil return system, to seriously affect oil return to find the root causes of, and blindly added oil is dangerous. Even if the oil level being low, but also pay attention to sudden and large returns lubricating oil (such as after defrost) may cause danger. Attack caused by liquid lubricants are not uncommon.

Compressor Failure Analysis (3) - lack of lubrication and lack of lubrication

1. Lack of oil

Lack of oil is very easy to identify one of the compressor failure, compressor short of oil in the crankcase oil when little or no oil.

Compressor is a special pump, a large number of refrigerant gas being discharged from the folder and also take a small portion of oil (known as Ben oil or an oil spill.) Ben compressor oil is inevitable, but Ben is different oils speed. Semi-sealed piston compressor discharge in about 2-3% of the oil, while the scroll compressor is 0.5-1%. For a displacement 100m3/hr, crankcase oil storage capacity of 6 liters of 6-cylinder compressor, 3% of the rush of oil means that about 0.3-0.8 liters / minute Ben oil, or running back to the oil-free compressor time for ten minutes.

Discharge of the compressor oil does not return, the compressor will be short of oil. Compressor oil return in two ways, one is the oil separator oil return, the other is the return pipe back to the oil. Oil separator installed in the compressor discharge pipe on the road, generally isolated from 50-95% of the Ben oil, back to better effect, fast, greatly reducing the amount of oil into the system piping, which effectively extended the running time of no return oil . Particularly long cold storage refrigeration piping system, ice-making system and flooded the low temperature freeze-drying equipment, ten minutes after boot or even tens of minutes did not return very little fuel oil or return to the situation is not unusual, the design The system will not occur while the compressor low oil pressure shutdown problem. The installation of high efficiency cooling system can greatly extend the oil separator back to the oil-free compressor operation time, after the compressor start to ride back to the oil

phase of the crisis-free.

Separated from the oil will not enter the system, with the flow of refrigerant in the tube, the formation of the oil cycle. Lubricating oil into the evaporator, the temperature is low because of low solubility on the one hand, part of the oil separated from the refrigerant; the other hand, low temperature viscosity, separated from the oil easily attached to the pipe wall, flow is more difficult . Evaporating temperature is lower, back to the oil more difficult. This requires the evaporation of pipeline design and pipe way back to the design and construction must be conducive to return to the oil, a common practice is to use down-style pipeline design, and to ensure a larger flow rate. For particularly low temperature refrigeration systems, such as -85 ° C and -150 ° C cold chamber for medical, in addition to selection of efficient oil separator, but usually add special solvent to prevent blocking capillaries and expansion valve oil, and help return oil.

Practice, the evaporator and back to the trachea caused by improper road design back to the oil problem is not rare. For the R22 and R404A systems, flooded evaporator back to the oil is very difficult to design the system return lines must be very careful. For such systems, the use of highly efficient oil pipeline can greatly reduce the amount of oil into the system, effectively extending the boot back to the pipe back to the oil-free time.

When the compressor than the location of the evaporator is high, the vertical back to back on the oil pipe bending is required. Return bends to compact as much as possible to reduce the storage of oil. The spacing between the oil return to the right bend, bend back the amount of oil relatively long time, should add some oil.

Load the system return lines must also be careful. When the load is reduced, the back will reduce the gas velocity, the speed is too low is not conducive to return oil. In order to ensure oil return under low load, the vertical double suction riser pipe can be used. Compressor oil return is not conducive to frequent starts. Continuous operation time is very short because the compressor stopped, and returned too late to form a stable tracheal high-speed air flow, oil can only stay in the pipeline. Return less than Ben oil, compressor will be short of oil. The shorter operation time, longer pipelines, more complex systems, back to the oil problem is more prominent. For the safety switch is not closed hydraulic compressor (including the scroll compressor and rotary compressor) and some semi-hermetic compressors), damage caused by frequent starting is more and more. Compressor maintenance is equally important. Defrost when the evaporator temperature increases, the oil viscosity decreases, easy flow. After the defrost cycle, refrigerant velocity, the oil will stay focused on return to the compressor. Therefore, the defrost cycle of the frequency and duration of each also need to be carefully set to avoid large fluctuations in oil or oil strike.

Back when the refrigerant gas leakage of more speed will decrease, the speed is too low will cause oil pipe stuck in the back way, you can not quickly return to the compressor. Within the shell back to the compressor oil does not mean back to the crankcase. Crank chamber with the principle of negative pressure compressor oil return, if the piston due to wear caused by leaks, crankcase pressure rise, oil return check valve automatically closes the role of pressure difference, from the return pipe to return the oil to remain in motor chamber, unable to enter the crankcase, which is the return to the oil issue, the return of oil starvation will cause the same problem. In addition to wear such an incident

occurred in the old machine, refrigerant migration triggered by starting with a liquid can also cause problems within the oil return, but usually shorter, up to ten minutes.

The problem occurs when the oil return, the compressor oil level can be observed declining until the oil pressure safety device action. After the compressor is stopped, the crankcase oil level soon resume. Root of the problem back to the oil within the cylinder is leaking, it is timely replacement of worn piston assembly.

Hydraulic safety protection device will automatically stop short of oil, protect the compressor from damage. Not as the mirror and hydraulic oil closed compressor safety devices (including the rotor and the scroll compressor) and the air compressor, starvation without obvious symptoms, it will not shut down the compressor damaged unknowingly wear . Compressor noise, vibration or current is too large, may be short of oil on the compressor and system operation to determine the exact status of it is very important. Ambient temperature is too low may result in some hydraulic safety device failure will cause the compressor wear.

Compressor wear and tear caused by lack of oil is generally more uniform. If little or no oil lubrication, the bearing surface there will be intense friction, the temperature will rise rapidly in a few seconds. If electrical power is large enough, will continue to rotate the crankshaft, the crankshaft and the bearing surface is worn or scratched, or will be bearing crankshaft locking, stop turning. Reciprocating piston within the cylinder is the same movement, lack of lubrication can cause wear or scratch card in severe piston inside the cylinder will not exercise.

2. Insufficient lubrication

The immediate cause of wear and tear insufficient lubrication. Lack of oil will surely lead to lack of lubrication, but oil lubrication is not necessarily a lack of oil caused by lack of. The following three reasons can also cause lack of lubrication: oil can not reach the bearing surface; lubricants Although arrive bearing surface, but the viscosity is too small to form a film of adequate thickness; Although oil to reach the bearing surface, but due to overheating broken down, and can not play lubrication.

压缩机常见三种详细故障分析

压缩机常见故障分析(1)——电机烧毁

电动机压缩机（以下简称压缩机）的故障可分为电机故障和机械故障(包括曲轴，连杆，活塞，阀片，缸盖垫等)。机械故障往往使电机超负荷运转甚至堵转，是电机损坏的主要原因之一。

电机的损坏主要表现为定子绕组绝缘层破坏（短路）和断路等。定子绕组损坏后很难及时被发现，最终可能导致绕组烧毁。绕组烧毁后，掩盖了一些导致烧毁的现象或直接原因，使得事后分析和原因调查比较困难。

然而，电机的运转离不开正常的电源输入，合理的电机负荷，良好的散热和绕组漆包线绝缘层的保护。从这几方面入手，不难发现绕组烧毁的原因不外乎如下六种：(1)异常负荷和堵转；(2)金属屑引起的绕组短路；(3)接触器问题；(4)电源缺相和电压异常；(5)冷却不足；(6)用压缩机抽真空。实际上，多种因素共同促成的电机损坏更为常见。

1.异常负荷和堵转

电机负荷包括压缩气体所需负荷以及克服机械摩擦所需负荷。压比过大，或压差过大，会使压缩过程更为困难；而润滑失效引起的摩擦阻力增加，以及极端情况下的电机堵转，将大大增加电机负荷。

润滑失效，摩擦阻力增大，是负荷异常的首要原因。回液稀释润滑油，润滑油过热，润滑油焦化变质，以及缺油等都会破坏正常润滑，导致润滑失效。回液稀释润滑油，影响摩擦面正常油膜的形成，甚至冲刷掉原有油膜，增加摩擦和磨损。压缩机过热会引起使润滑油高温变稀甚至焦化，影响正常油膜的形成。系统回油不好，压缩机缺油，自然无法维持正常润滑。曲轴高速旋转，连杆活塞等高速运动，没有油膜保护的摩擦面会迅速升温，局部高温使润滑油迅速蒸发或焦化，使该部位润滑更加困难，数秒钟内可引起局部严重磨损。润滑失效，局部磨损，使曲轴转动需要更大力矩。小功率压缩机（如冰箱，家用空调压缩机）由于电机扭矩小，润滑失效后常出现堵转（电机无法转动）现象，并进入“堵转－热保护－堵转”死循环，电机烧毁只是时间问题。而大功率半封闭压缩机电机扭矩很大，

局部磨损不会引起堵转，电机功率会在一定范围内随负荷而增大，从而引起更为严重的磨损，甚至引起咬缸（活塞卡在气缸内），连杆断裂等严重损坏。

堵转时的电流（堵转电流）大约是正常运行电流的4－8倍。电机启动瞬间，电流的峰值可接近或达到堵转电流。由于电阻放热量与电流的平方成正比，启动和堵转时的电流会使绕组迅速升温。热保护可以在堵转时保护电极，但一般不会有很快的响应，不能阻止频繁启动等引起的绕组温度变化。频繁启动和异常负荷，使绕组经受高温考验，会降低漆包线的绝缘性能。

此外，压缩气体所需负荷也会随压缩比增大和压差增大而增大。因此将高温压缩机用于低温，或将低温压缩机用于高温，都会影响电机负荷和散热，是不合适的，会缩短电极使用寿命。

绕组绝缘性能变差后，如果有其它因素（如金属屑构成导电回路，酸性润滑油等）配合，很容易引起短路而损坏。

2.金属屑引起的短路

绕组中夹杂的金属屑是短路和接地绝缘值低的罪魁祸首。压缩机运转时的正常振动，以及每次启动时绕组受电磁力作用而扭动，都会促使夹杂于绕组间的金属屑与绕组漆包线之间的相对运动和摩擦。棱角锐利的金属屑会划伤漆包线绝缘层，引起短路。

金属屑的来源包括施工时留下的铜管屑，焊渣，压缩机内部磨损和零部件损坏（比如阀片破碎）时掉下的金属屑等。对于全封闭压缩机（包括全封闭涡旋压缩机），这些金属屑或碎粒会落在绕组上。对于半封闭压缩机，有些颗粒会随气体和润滑油在系统中流动，最后由于磁性聚集在绕组中；而有些金属屑（比如轴承磨损以及电机转子与定子磨损（扫膛）时产生的）会直接落在绕组上。绕组中聚集了金属屑后，发生短路只是一个时间问题。

需要特别提请注意的是双级压缩机。在双级压缩机中，回气以及正常的回油直接进入第一级（低压级）气缸，压缩后经中压管进入电机腔冷却绕组，然后和普通单级压缩机一样，进入第二级（高压级气缸）。回气中带有润滑油，已经使压缩过程如履薄冰，如果再有回液，第一级气缸的阀片很容易被打碎。碎阀片经中压管后可进入绕组。因此，双级压缩机比单级压缩机更容易出现金属屑引起的电机短路。

不幸的事情往往凑到一块，出问题的压缩机在开机分析时闻道的常常是润滑油的焦糊味。金属面严重磨损时温度是很高的，而润滑油在175ºC以上时开始焦化。系统中如果有较多水分（真空抽得不理想，润滑油和制冷剂含水量大，负压回气管破裂后空气进入等），润滑油就可能出现酸性。酸性润滑油会腐蚀铜管和绕组绝缘层，一方面，它会引起镀铜现象；另一方面，这种含有铜原子的酸性润滑油的绝缘性能很差，为绕组短路提供了条件。

3.接触器问题

接触器是电机控制回路中重要部件之一，选型不合理可以毁坏最好的压缩机。按负载正确选择接触器是极其重要的。

接触器必须能满足苛刻的条件，如快速循环，持续超载和低电压。它们必须有足够大的面积以散发负载电流所产生的热量，触点材料的选择必须在启动或堵转等大电流情况下能防止焊合。

为了安全可靠，压缩机接触器要同时断开三相电路。谷轮公司不推荐断开二相电路的方法。

在美国，谷轮公司认可的接触器必须满足如下四项：

·接触器必须满足ARI标准780-78“专用接触器标准”规定的工作和测试准则。·制造商必须保证接触器在室温下，在最低铭牌电压的80％时能闭合。

·当使用单个接触器时，接触器额定电流必须大于电机铭牌电流额定值(RLA).同时，接触器必须能承受电机堵转电流。如果接触器下游还有其它负载，比如电机风扇等，也必须考虑。

·当使用两个接触器时，每个接触器的分绕组堵转额定值必须等于或大于压缩机半绕组堵转额定值。

接触器的额定电流不能低于压缩机铭牌上的额定电流。规格小或质量低劣的接触器无法经受压缩机启动，堵转和低电压时的大电流冲击，容易出现单相或多相触点抖动,焊接甚至脱落的现象，引起电机损坏。

触点抖动的接触器频繁地启停电机。电机频繁启动，巨大的启动电流和发热,会加剧绕组绝缘层的老化。每次启动时，磁性力矩使电机绕组有微小的移动和相互摩擦。如果有其它因素配合（如金属屑，绝缘性差的润滑油等），很容易引起绕

组间短路。热保护系统并未设计成能防止这种毁坏。此外，抖动的接触器线圈容易失效。如果有接触线圈损坏，容易出现单相状态。

如果接触器选型偏小，触头不能承受电弧和由于频繁开停循环或不稳定控制回路电压产生的高温，可能焊合或从触头架中脱落。焊合的触头将产生永久性单相状态，使过载保护器持续地循环接通和断开。

需要特别强调的是，接触器触点焊合后，依赖接触器断开压缩机电源回路的所有控制（比如高低压控制，油压控制，融霜控制等）将全部失效，压缩机处于无保护状态。

因此，当电机烧毁后，检查接触器是必不可少的工序。接触器是导致电机损坏的一个常常被人遗忘的重要原因。

压缩机常见故障分析(2)——液击

1.过程与现象

(1)吸气阀片断裂

压缩机是压缩气体的机器。通常，活塞每分钟压缩气体1450次（半封压缩机）或2900次（全封压缩机），即完成一次吸气或排气过程的时间为0.02秒甚至更短。阀板上的吸排气孔径的大小以及吸排气阀片的弹性与强度均是按照气体流动而设计的。从阀片受力角度讲，气体流动时产生的冲击力是比较均匀的。

液体的密度是气体的数十甚至数百倍，因而液体流动时的动量比气体大得多的，产生的冲击力也大得多。吸气中夹杂较多液滴进入气缸时的流动属于两相流。两相流在吸气阀片上产生的冲击不仅强度大而且频率高，就好像台风夹杂着鹅卵石敲打在玻璃窗上，其破坏性是不言而喻的。吸气阀片断裂是液击的典型特征和过程之一。

(2)连杆断裂

压缩行程的时间约0.02秒，而排气过程会更短暂。气缸中的液滴或液体必须在如此短的时间内从排气孔排出，速度和动量是很大的。排气阀片的情况与吸气阀片相同，不同之处在于排气阀片有限位板和弹簧片支撑，不容易折断。冲击严重时，限位板也会变形翘起。

如果液体没有及时蒸发和排出气缸，活塞接近上止点时会压缩液体，由于时间很短，这一压缩液体的过程好像是撞击，缸盖中也会传出金属敲击声。压缩液体是液击现象的另一部分或过程。

液击瞬间产生的高压具有很大的破环性，初人们熟悉的连杆弯曲甚至断裂外，其他压缩受力件（阀板、阀板垫、曲轴、活塞、活塞销等）也会有变形或损坏，但往往被忽视，或者与排汽压力过高混为一谈。检修压缩机时，人们会很容易发现弯曲或断裂的连杆，并给予替换，而忘记检查其他零件是否有变形或损坏，从而为以后的故障埋下祸根。

液击造成的连杆断裂不同于抱轴和活塞咬缸，是可以分辨出来的。首先，液击造成连杆弯曲或断裂是在短时间内发生的，连杆两端的活塞和曲轴运动自如，一般不会有严重磨损引起的抱轴或咬缸。尽管吸气阀片折断后，阀片碎屑偶尔也会引起活塞和气缸面严重划伤，但表面划伤与润滑失效引起磨损很不同。其次，液击引起的连杆断裂是由压力造成的，连杆和断茬有挤压特征。尽管活塞咬缸后的连杆断裂也有挤压可能，但前提是活塞必须卡死在气缸。抱轴后的连杆折断就更不同了，连杆大头和曲轴有严重磨损，造成折断的力属于剪切力，断茬也不一样。最后，抱轴和咬缸前，电机会超负荷运转，电机发热严重，热保护器会动作。

2.原因分析

显然，能引起压缩机液击的液体不外乎如下几种来源：1）回液，即从蒸发器中流回压缩机的液态制冷剂或润滑油；2）带液启动时的泡沫；3）压缩机内的润滑油太多。本文将对这几种原因逐一分析。

(1)回液

通常，回液是指压缩机运行时蒸发器中的液态制冷剂通过吸气管路回到压缩机的现象或过程。

对于使用膨胀阀的制冷系统，回液与膨胀阀选型和使用不当密切相关。膨胀阀选型过大、过热度设定太小、感温包安装方法不正确或绝热包扎破损、膨胀阀失灵都可能造成回液。对于使用毛细管的小制冷系统而言，加液量过大会引起回液。利用热气融霜的系统容易发生回液。无论采用四通阀进行热泵运行，还是采用热气旁通阀时的制冷运行，热气融霜后会在蒸发器内形成大量液体，这些液体在随后的制冷运行开始时既有可能回到压缩机。

此外，蒸发器结霜严重或风扇故障时传热变差，未蒸发的液体会引起回液。冷库温度频繁波动也会引起膨胀阀反应失灵而引起回液。

回液引起的液击事故大多发生在空气冷却型（简称风冷或空冷）半封闭压缩机和单机双级压缩机中，因为这些压缩机的气缸与回气管是直接相通的，一旦回液，就很容易引发液击事故。即使没有引起液击，回液进入汽缸将稀释或冲刷掉活塞及汽缸壁上的润滑油，加剧活塞磨损。

对于回气（制冷剂蒸汽）冷却型半封闭和全封闭压缩机，回液很少引起液击。但会稀释曲轴箱内的润滑油。含有大量液态制冷剂的润滑油粘度低，在摩擦面不能形成足够的油膜，导致运动件的快速磨损。另外，润滑油中的制冷剂在输送过程中遇热会沸腾，影响润滑油的正常输送。而距离油泵越远，问题就越明显越严重。如果电机端的轴承发生严重的磨损，曲轴可能向一侧沉降，容易导致定子扫堂及电机烧毁。

显然，回液不仅会引起液击，还会稀释润滑油造成磨损。磨损时电机的负荷和电流会大大增加，久而久之将引起电机故障。

对于回液较难避免的制冷系统，安装气液分离器和采用抽空停机控制可以有效阻止或降低回液的危害。

（2）带液启动

回气冷却型压缩机在启动时，曲轴箱内的润滑油剧烈起泡的现象叫带液启动。带液启动时的起泡现象可以在油视镜上清楚地观察到。带液启动的根本原因是润滑油中溶解的以及沉在润滑油下面了大量的制冷剂，在压力突然降低时突然沸腾，并引起润滑油的起泡现象。这种现象很像日常生活中人们突然打开可乐瓶时的可乐起泡现象。起泡持续的时间长短与制冷剂的量有关，通常为几分钟或十几分钟。大量泡沫漂浮在油面上，甚至充满了曲轴箱。一旦通过进气道吸入气缸，泡沫会还原成液体（润滑油与制冷剂的混合物），很容易引起液击。显然，带液启动引起的液击只发生在启动过程。

与回液不同，引起带液启动的制冷剂是以“制冷剂迁移”的方式进入曲轴箱的。制冷剂迁移是指压缩机停止运行时，蒸发器中的制冷剂以气体形式，通过回气管路进入压缩机并被润滑油吸收，或在压缩机内冷凝后与润滑油混合的过程或现象。

压缩机停机后，温度会降低，而压力会升高。由于润滑油中的制冷剂蒸汽分压低，就会吸收油面上的制冷剂蒸气，造成曲轴箱气压低于蒸发器气压的现象。油温愈低，蒸汽压力越低，对制冷剂蒸汽的的吸收力就愈大。蒸发器中的蒸汽就会慢慢向曲轴箱“迁移”。此外，如果压缩机在室外，天气寒冷时或在夜晚，其温度往往比室内的蒸发器低，曲轴箱内的压力也就低，制冷剂迁移到压缩机后也容易被冷凝而进入润滑油。

制冷剂迁移是一个很缓慢的过程。压缩机停机时间越长，迁移到润滑油中的制冷剂就会越多。只要蒸发器中存在液态制冷剂，这一过程就会进行。由于溶解了制冷剂的润滑油较重，它会沉在曲轴箱的底部，而浮在上面的润滑油还可以吸收更多的制冷剂。

除容易引起液击外，制冷剂迁移还会稀释润滑油。很稀的润滑油被油泵送到各摩擦面后，可能冲涮掉原有油膜，引起严重磨损（这种现象常称为制冷剂冲刷）。过渡磨损会使配合间隙变大，引起漏油，从而影响较远部位的润滑，严重时会引起油压保护器动作。

由于结构原因，空冷压缩机启动时曲轴箱压力的降低会缓慢得多，起泡现象不很剧烈，泡沫也很难进入气缸，因此空冷压缩机不存在带液启动液击问题。

理论上讲，压缩机安装曲轴箱加热器（电热器）可以有效防止制冷剂迁移。短时间停机（比如在夜间）后，维持曲轴箱加热器通电，可以使润滑油温度略高于系统其它部位，制冷剂迁移不会发生。长时间停机不用（比如一个冬天）后，开机前先加热润滑油几个或十几个小时，可以蒸发掉润滑油中的大部分制冷剂，既可以大大减小带液启动时液击的可能性，也可以降低制冷剂冲刷造成的危害。但实际应用中，停机后维持加热器供电或者开机前十几小时先给加热器供电，是有难度的。因此，曲轴箱加热器的实际效果会大打折扣。

对于较大系统，停机前让压缩机抽干蒸发器中液态制冷剂（称为抽空停机），可以从根本上避免制冷剂迁移。而回气管路上安装气液分离器，可以增加制冷剂迁移的阻力，降低迁移量。

当然，通过改进压缩机结构，可以阻止制冷剂迁移，并减缓润滑油起泡程度。通过改进回气冷却型压缩机内的回油路径，在电机腔与曲轴箱迁移的通道上增加关卡（回油泵等），停机后即可切断通路，制冷剂无法进入曲轴腔；减小进气道与

曲轴箱的通道截面可以减缓开机时曲轴箱压力下降速度，进而控制起泡的程度和泡沫进入气缸的量。

(3)润滑油太多

半封闭压缩机通常都有油视镜，以便观察油位高低。油位高于油视镜范围，说明油太多了。油位太高，高速旋转的曲轴和连杆大头就可能频繁撞击油面，引起润滑油大量飞溅。飞溅的润滑油一旦窜入进气道，带入气缸，就可能引起液击。大型制冷系统安装调试时，往往需要适当补充润滑油。但对于回油不好的系统，要认真寻找影响回油的根源，一味地补充润滑油是危险的。即使暂时油位不高，也要注意润滑油突然大量返回时（比如化霜后）可能造成的危险。润滑油引起的液击并不罕见。

压缩机故障分析(3)——缺油与润滑不足

1.缺油

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。

压缩机是一个特殊的气泵，大量制冷剂气体在被排出的同时也夹带走一小部分润滑油（称为奔油或跑油）。压缩机奔油是无法避免的，只是奔油速度有所不同。半封活塞式压缩机排气中大约有2-3％的润滑油，而涡旋压缩机为0.5-1%。对于一台排量为100m3/hr、曲轴箱储油量为6升的6缸压缩机，3％的奔油意味着大约0.3-0.8升／分钟的奔油量，或压缩机无回油运转时间为十几分钟。

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。

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。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。

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路内。回油少于奔油，压缩机就会缺油。运转时间越短，管线越长，系统越复杂，回油问题就越突出。对于没有油压安全开关的全封闭压缩机（包括涡旋压缩机和转子压缩机）和部分半封闭压缩机），频繁启动引起的损坏是比较多的。

压缩机维护同样重要。除霜时蒸发器温度升高，润滑油粘度减小，易于流动。除霜循环过后，制冷剂流速大，滞留的润滑油会集中返回压缩机。因此，除霜循环的频率以及每次持续的时间也需仔细设定，避免油位大幅度波动甚至油击。

制冷剂泄漏较多时回气速度会降低，速度太低会造成润滑油滞留在回气管路，不能快速返回压缩机。

润滑油回到压缩机壳体内并不等于回到曲轴箱。采用曲轴腔负压回油原理的压缩机，如果活塞因磨损等引起泄漏时，曲轴箱的压力上升，回油单向阀受压差作用而自动关闭，从回气管返回的润滑油就滞留在电机腔中，无法进入曲轴箱，这就

是内回油问题，内回油问题同样会引起缺油。这种事故除发生于磨损的旧机器中，制冷剂迁移引发的带液启动也会造成内回油困难，但通常时间较短，最多十几分钟。

出现内回油问题时，可以观察到压缩机油位不断下降，直至油压安全装置动作。压缩机停机后，曲轴箱的油位很快恢复。内回油问题的根源在于气缸泄漏，应及时更换磨损活塞组件。

油压安全护装置在缺油时会自动停机，保护压缩机不受损坏。没有视油镜和油压安全装置的全封闭压缩机（包括转子和涡旋压缩机）以及风冷压缩机，缺油时没有明显症状，也不会停机，压缩机会在不知不觉中磨损损坏。压缩机噪音、震动或电流过大，可能与缺油有关，对压缩机和系统运行状况的准确判断就显得非常重要。环境温度过低有可能导致一些油压安全装置失灵，会造成压缩机磨损。压缩机缺油引起的磨损一般比较均匀。如果润滑油很少或者没有油，轴承表面就会出现剧烈的摩擦，温度会在几秒内迅速升高。如果电机的功率足够大，曲轴会继续转动，曲轴和轴承表面会被磨损或划伤，否则曲轴会被轴承抱死，停止转动。活塞在气缸内的往复运动也是一样的，缺油会导致磨损或划伤，严重时活塞会卡在气缸内不能运动。

2.润滑不足

磨损的直接原因是润滑不足。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。

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。

回液是常见的系统问题，回液的一大危害在于稀释润滑油。被稀释的润滑油到达摩擦面后，粘度低，不能形成足够厚度的保护油膜，久而久之会造成磨损。回液量比较大时，润滑油会很稀，不但不能起到润滑作用，而且还会溶解冲刷原有油膜，引起制冷剂冲刷。

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。

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。

化工英文文献翻译

Heavy Oil Development Technology of Liaohe Oilfield Han Yun (Scientific Research Information Department Exploration&Development Research Institute，Liaohe Oilfield Company) Liaohe Oilfield，the largest heavy oil production base in China，features in various reservoir types，deep burial，and wide range of crude oil viscosity．For many years，a series of technologies have been developed for different oil products and reservoir types of the oilfield，of which water flooding，foam slug drive，steam stimulation，steam drive,and SAGD are the main technologies. After continuous improvement，they have been further developed and played an important role in the development of heavy oil in the oilfield． Liaohe Oilfield is abundant in heavy oil resources，46％of the total proved reserves of Liaohe Oilfield Company. Horizontally the resources concentrates in the West Depression and the southern plunging belt of the Central Uplift in Liaohe Rift. Vertically,it is mainly distributed in Paleocene Shahejie Formation(ES). The distinctive geological feature of Liaohe 0ilfield is manifested in three aspects：first，the heavy oil reservoirs are deeply buried and 80％of them are buried more than 900m deep；second，the heavy oil viscosity ranges widely．For most of the reservoirs．the dead oil viscosity ranges in 100～100000mPa·s with the maximum 650000mPa·s.Third the reservoir types are various with complicated oil—water relationship，most of the reservoirs are edge water and bosom water reservoirs and there are also edge water reservoirs，top water reservoirs and bosom water reservoirs．For more than 20 years of development，Liaohe Oilfield has developed series of heavy oil development technologies for different oil products and different types of reservoirs，such as water flooding, foam slug drive,steam stimulation steam drive and SAGD．The most difficult issues have been overcome in the development of the super

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关于力的外文文献翻译、中英文翻译、外文翻译

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1外文文献翻译原文及译文汇总

华北电力大学科技学院 毕业设计（论文）附件 外文文献翻译 学号：121912020115姓名：彭钰钊 所在系别：动力工程系专业班级：测控技术与仪器12K1指导教师：李冰 原文标题：Infrared Remote Control System Abstract 2016 年 4 月 19 日

红外遥控系统 摘要 红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。红外收发器产品具有成本低，小型化，传输速率快，点对点安全传输，不受电磁干扰等特点，可以实现信息在不同产品之间快速、方便、安全地交换与传送，在短距离无线传输方面拥有十分明显的优势。红外遥控收发系统的设计在具有很高的实用价值，目前红外收发器产品在可携式产品中的应用潜力很大。全世界约有1亿5千万台设备采用红外技术，在电子产品和工业设备、医疗设备等领域广泛使用。绝大多数笔记本电脑和手机都配置红外收发器接口。随着红外数据传输技术更加成熟、成本下降，红外收发器在短距离通讯领域必将得到更广泛的应用。 本系统的设计目的是用红外线作为传输媒质来传输用户的操作信息并由接收电路解调出原始信号，主要用到编码芯片和解码芯片对信号进行调制与解调，其中编码芯片用的是台湾生产的PT2262，解码芯片是PT2272。主要工作原理是：利用编码键盘可以为PT2262提供的输入信息，PT2262对输入的信息进行编码并加载到38KHZ的载波上并调制红外发射二极管并辐射到空间，然后再由接收系统接收到发射的信号并解调出原始信息，由PT2272对原信号进行解码以驱动相应的电路完成用户的操作要求。 关键字：红外线；编码；解码；LM386；红外收发器。 1 绪论

计算机网络-外文文献-外文翻译-英文文献-新技术的计算机网络

New technique of the computer network Abstract The 21 century is an ages of the information economy, being the computer network technique of representative techniques this ages, will be at very fast speed develop soon in continuously creatively, and will go deep into the people's work, life and study. Therefore, control this technique and then seem to be more to deliver the importance. Now I mainly introduce the new technique of a few networks in actuality live of application. keywords Internet Network System Digital Certificates Grid Storage 1. Foreword Internet turns 36, still a work in progress Thirty-six years after computer scientists at UCLA linked two bulky computers using a 15-foot gray cable, testing a new way for exchanging data over networks, what would ultimately become the Internet remains a work in progress. University researchers are experimenting with ways to increase its capacity and speed. Programmers are trying to imbue Web pages with intelligence. And work is underway to re-engineer the network to reduce Spam (junk mail) and security troubles. All the while threats loom: Critics warn that commercial, legal and political pressures could hinder the types of innovations that made the Internet what it is today. Stephen Crocker and Vinton Cerf were among the graduate students who joined UCLA professor Len Klein rock in an engineering lab on Sept. 2, 1969, as bits of meaningless test data flowed silently between the two computers. By January, three other "nodes" joined the fledgling network.

10kV小区供配电英文文献及中文翻译

在广州甚至广东的住宅小区电气设计中,一般都会涉及到小区的高低压供配电系统的设计.如10kV高压配电系统图,低压配电系统图等等图纸一大堆.然而在真正实施过程中,供电部门(尤其是供电公司指定的所谓电力设计小公司)根本将这些图纸作为一回事,按其电脑里原有的电子档图纸将数据稍作改动以及断路器按其所好换个厂家名称便美其名曰设计(可笑不?),拿出来的图纸根本无法满足电气设计的设计意图,致使严重存在以下问题:(也不知道是职业道德问题还是根本一窍不通) 1.跟原设计的电气系统货不对板,存在与低压开关柜后出线回路严重冲突,对实际施工造成严重阻碍,经常要求设计单位改动原有电气系统图才能满足它的要求(垄断的没话说). 2.对消防负荷和非消防负荷的供电(主要在高层建筑里)应严格分回路(从母线段)都不清楚,将消防负荷和非消防负荷按一个回路出线(尤其是将电梯和消防电梯,地下室的动力合在一起等等,有的甚至将楼顶消防风机和梯间照明合在一个回路,以一个表计量). 3.系统接地保护接地型式由原设计的TN-S系统竟曲解成"TN-S-C-S"系统(室内的还需要做TN-C,好玩吧?),严格的按照所谓的"三相四线制"再做重复接地来实施,导致后续施工中存在重复浪费资源以及安全隐患等等问题.. ............................(违反建筑电气设计规范等等问题实在不好意思一一例举,给那帮人留点混饭吃的面子算了) 总之吧,在通过图纸审查后的电气设计图纸在这帮人的眼里根本不知何物,经常是完工后的高低压供配电系统已是面目全非了,能有百分之五十的保留已经是谢天谢地了. 所以.我觉得:住宅建筑电气设计,让供电部门走!大不了留点位置,让他供几个必需回路的电,爱怎么折腾让他自个怎么折腾去.. Guangzhou, Guangdong, even in the electrical design of residential quarters, generally involving high-low cell power supply system design. 10kV power distribution systems, such as maps, drawings, etc. low-voltage distribution system map a lot. But in the real implementation of the process, the power sector (especially the so-called power supply design company appointed a small company) did these drawings for one thing, according to computer drawings of the original electronic file data to make a little change, and circuit breakers by their the name of another manufacturer will be sounding good design (ridiculously?), drawing out the design simply can not meet the electrical design intent, resulting in a serious following problems: (do not know or not know nothing about ethical issues) 1. With the original design of the electrical system not meeting board, the existence and low voltage switchgear circuit after qualifying serious conflicts seriously hinder the actual construction, often require changes to the original design unit plans to meet its electrical system requirements (monopoly impress ). 2. On the fire load and fire load of non-supply (mainly in high-rise building in) should be strictly sub-loop (from the bus segment) are not clear, the fire load and fire load of non-qualifying press of a circuit (especially the elevator and fire elevator, basement, etc.

材料英文文献翻译

The development of plastic mould China's industrial plastic moulds from the start to now, after more than half a century, there has been great development, mold levels have been greatly enhanced. Mould has been at large can produce 48-inch big-screen color TV Molded Case injection mold, 6.5 kg capacity washing machine full of plastic molds, as well as the overall car bumpers and dashboards, and other plastic mould precision plastic molds, the camera is capable of producing plastic mould , multi-cavity mold small modulus gear and molding mold. --Such as Tianjin and Yantai days Electrical Co., Ltd Polaris IK Co. manufactured multi-cavity mold VCD and DVD gear, the gear production of such size precision plastic parts, coaxial, beating requirements have reached a similar foreign the level of product, but also the application of the latest gear design software to correct contraction as a result of the molding profile error to the standard involute requirements. Production can only 0.08 mm thickness of a two-cavity mold and the air Cup difficulty of plastic doors and windows out of high modulus, and so on. Model cavity injection molding manufacturing accuracy of 0.02 to 0.05 mm, surface roughness Ra0.2 μ m, mold quality, and significantly increase life expectancy, non-hardening steel mould life up to 10~ 30 million, hardening steel form up to 50 ~ 10 million times, shorten the delivery time than before, but still higher than abroad,and the gap between a specific data table. Process, the multi-material plastic molding die, efficient multicolor injection mould, inserts exchange structure and core pulling Stripping the innovative design has also made great progress. Gas-assisted injection molding, the use of more mature technologies, such as Qingdao Hisense Co., Ltd., Tianjin factory communications and broadcasting companies, such as mold manufacturers succeeded in 29 ~ 34-inch TV thick-walled shell, as well as some parts on the use of gas-assisted mould technology Some manufacturers also use the C-MOLD gas-assisted software and achieved better results. Prescott, such as Shanghai, such as the new company will provide users with gas-assisted molding equipment and technology. Began promoting hot runner mold, and some plants use rate of more than 20 percent, the general heat-thermal hot runner, or device, a small number of units with the world's advanced level of rigorous hot runner-needle device, a small number of units with World advanced level of rigorous needle-hot runner mould. However, the use of hot runner overall rate of less than 10%, with overseas compared to 50 ~ 80%, the gap larger. In the manufacturing technology, CAD / CAM / CAE technology on the level of application of a new level to the enterprise for the production of household appliances representatives have introduced a considerable number of CAD / CAM systems, such as the United States EDS UG Ⅱ,

文献翻译英文原文

https://www.wendangku.net/doc/ca5114377.html,/finance/company/consumer.html Consumer finance company The consumer finance division of the SG group of France has become highly active within India. They plan to offer finance for vehicles and two-wheelers to consumers, aiming to provide close to Rs. 400 billion in India in the next few years of its operations. The SG group is also dealing in stock broking, asset management, investment banking, private banking, information technology and business processing. SG group has ventured into the rapidly growing consumer credit market in India, and have plans to construct a headquarters at Kolkata. The AIG Group has been approved by the RBI to set up a non-banking finance company (NBFC). AIG seeks to introduce its consumer finance and asset management businesses in India. AIG Capital India plans to emphasize credit cards, mortgage financing, consumer durable financing and personal loans. Leading Indian and international concerns like the HSBC, Deutsche Bank, Goldman Sachs, Barclays and HDFC Bank are also waiting to be approved by the Reserve Bank of India to initiate similar operations. AIG is presently involved in insurance and financial services in more than one hundred countries. The affiliates of the AIG Group also provide retirement and asset management services all over the world. Many international companies have been looking at NBFC business because of the growing consumer finance market. Unlike foreign banks, there are no strictures on branch openings for the NBFCs. GE Consumer Finance is a section of General Electric. It is responsible for looking after the retail finance operations. GE Consumer Finance also governs the GE Capital Asia. Outside the United States, GE Consumer Finance performs its operations under the GE Money brand. GE Consumer Finance currently offers financial services in more than fifty countries. The company deals in credit cards, personal finance, mortgages and automobile solutions. It has a client base of more than 118 million customers throughout the world

中英文文献以及翻译(化工类)

Foreign material： Chemical Industry 1.Origins of the Chemical Industry Although the use of chemicals dates back to the ancient civilizations, the evolution of what we know as the modern chemical industry started much more recently. It may be considered to have begun during the Industrial Revolution, about 1800, and developed to provide chemicals roe use by other industries. Examples are alkali for soapmaking, bleaching powder for cotton, and silica and sodium carbonate for glassmaking. It will be noted that these are all inorganic chemicals. The organic chemicals industry started in the 1860s with the exploitation of William Henry Perkin’s discovery if the first synthetic dyestuff—mauve. At the start of the twentieth century the emphasis on research on the applied aspects of chemistry in Germany had paid off handsomely, and by 1914 had resulted in the German chemical industry having 75% of the world market in chemicals. This was based on the discovery of new dyestuffs plus the development of both the contact process for sulphuric acid and the Haber process for ammonia. The later required a major technological breakthrough that of being able to carry out chemical reactions under conditions of very high pressure for the first time. The experience gained with this was to stand Germany in good stead, particularly with the rapidly increased demand for nitrogen-based compounds (ammonium salts for fertilizers and nitric acid for explosives manufacture) with the outbreak of world warⅠin 1914. This initiated profound changes which continued during the inter-war years (1918-1939). Since 1940 the chemical industry has grown at a remarkable rate, although this has slowed significantly in recent years. The lion’s share of this growth has been in the organic chemicals sector due to the development and growth of the petrochemicals area since 1950s. The explosives growth in petrochemicals in the 1960s and 1970s was largely due to the enormous increase in demand for synthetic polymers such as polyethylene, polypropylene, nylon, polyesters and epoxy resins. The chemical industry today is a very diverse sector of manufacturing industry, within which it plays a central role. It makes thousands of different chemicals which

变电站_外文翻译_外文文献_英文文献_变电站的综合概述

英文翻译 A comprehensive overview of substations Along with the economic development and the modern industry developments of quick rising, the design of the power supply system become more and more completely and system. Because the quickly increase electricity of factories, it also increases seriously to the dependable index of the economic condition, power supply in quantity. Therefore they need the higher and more perfect request to the power supply. Whether Design reasonable, not only affect directly the base investment and circulate the expenses with have the metal depletion in colour metal, but also will reflect the dependable in power supply and the safe in many facts. In a word, it is close with the economic performance and the safety of the people. The substation is an importance part of the electric power system, it is consisted of the electric appliances equipments and the Transmission and the Distribution. It obtains the electric power from the electric power system, through its function of transformation and assign, transport and safety. Then transport the power to every place with safe, dependable, and economical. As an important part of power’s transport and control, the transformer substation must change the mode of the traditional design and control, then can adapt to the modern electric power system, the development of modern industry and the of trend of the society life. Electric power industry is one of the foundations of national industry and national economic development to industry, it is a coal, oil, natural gas, hydropower, nuclear power, wind power and other energy conversion into electrical energy of the secondary energy industry, it for the other departments of the national economy fast and stable development of the provision of adequate power, and its level of development is a reflection of the country's economic development an important indicator of the level. As the power in the industry and the importance of the national economy, electricity transmission and distribution of electric energy used in these areas is an indispensable component.。Therefore, power transmission and distribution is critical. Substation is to enable superior power plant power plants or power after adjustments to the lower load of books is an important part of power transmission. Operation of its functions, the capacity of a direct impact on the size of the lower load power, thereby affecting the industrial production and power consumption.Substation system if a link failure, the system will protect the part of action. May result in power outages and so on, to the production and living a great disadvantage. Therefore, the substation in the electric power system for the protection of electricity reliability,