船舶空调装置制冷不良实例分析与处理

船舶空调装置制冷不良实例分析与处理Analysis and treatment of poor refrigeration in marine air conditioning unitRequirements for ship air conditioning: marine air conditioning is mainly used to meet the requirements of people's comfort and hygiene for work and living environment. The temperature, humidity and other air conditions are not very strict, allowing changes in a larger range, belonging to comfort equipment.(1) temperature: the temperature condition is 19~24 in winter and 21~28 in summer. The standard in our country is 19~22 degrees in winter and 24~28 in summer.(2) humidity: people are not sensitive to the humidity of the air; the summer air conditioning adopts the wet method, the control is from 40% to 50%, and the winter is between 30% and 40%.(3) freshness: freshness is the degree of cleanliness and freshness of the air. If only from the need for oxygen, the supply will be at 2.4m3 / h.(4) airflow speed: indoor airflow rate should be 0.15 ~ 0.20m / s, the maximum is not more than 0.35m / s.A wheel has two independent air conditioning units, the smaller for the engine room to send cold air, the larger for the living area and kitchen and other places to send air, hot air. This article mainly carries on the brief analysis to the latter. Twosets of systems are using R22 as refrigerant, the system component:(1): oil separator installed in the compressor discharge between the end and the condensing end is the oil separated mixed refrigerant steam in order to avoid too much oil into the condenser and the system, and the influence of heat pipe blocking. The oil separator can also send the separated oil back to the compressor in time, so as to avoid the compressor from losing oil, so as to ensure the long-term safe and reliable operation of the compressor.(2) condenser: its function is to cool the high-pressure and high temperature gaseous refrigerant discharged from the compressor into liquid, which can be recycled by the system.(3) reservoir: liquid refrigerant can enable the device to store a certain amount, due to the change of the condition of refrigeration equipment caused by different evaporation pressure, so that the number of circulating refrigerant in the system change greatly, avoid liquid refrigerant level rise can be reduced when the refrigerant cycle, immersion cooler tube and condenser, keep the cooling liquid enough in the refrigerant circulation increases slightly when the leak or system.(4) expansion valve: balanced thermal expansion valve.(5) evaporator: the refrigerant is evaporated in the tube, so that the air near the evaporator is cooled, forced convection is formed, and the temperature of the air is graduallydecreased. ,(6): cooling liquid refrigerant into the evaporator coil in the throttling expansion valve in the refrigerant will heat at low pressure evaporation, absorb heat from the air, the air temperature is reduced, so as to realize refrigeration. In order to make the pressure evaporation tube will not increase because of the refrigerant flowing in the refrigerant compressor vaporization, out of a low pressure evaporator is maintained, while the high temperature high pressure gaseous refrigerant to the condenser, the gaseous refrigerant heat to liquefaction, and then again into the circulatory system.3 introduction of failure process:The August 20, 2004 round found living area temperature accommodation, to check the fan between air temperature, air temperature rises to starboard sent 18~20%, suction pressure decreased to non normal value. Preliminary determination of refrigerant shortage may be caused by a leak,The machine leak is not unusual, and difficult to check line and then charge into the evaporator, refrigerant, and start running well after liquid filling, but a few hours after the oil pressure began to decline, the suction pressure drop, temperature accommodation began to increase rapidly after the shutdown, the condenser side cover is opened, the oil reservoir outlet valve see a water pipe ajar with fog, as the condenser leaked a lot of refrigerant, will destroy the pipe plugging after filling refrigerant start running well. But since then, destruction of condenser and several times during the voyagedue to excessive water damage, plugging after inadequate condensing refrigerant insufficient refrigeration machine was discontinued for several days, maintenance after the start, the cooling effect is still poor, but also because of insufficient suction pressure and automatic shutdown, ice jam at the beginning of judgment for the charge number of refrigerant bring too much water the. Open the liquid return pipe trap drain water, found oil and refrigerant mixture up to hundreds of grams, remove the trap / filter, found shell water. Therefore, to determine the problem is not so simple to bring water cooling.4 cause analysis and brief introduction of mechanismAnalysis of 4.1 failure: analysis of water entering the system reason of the new refrigerant filled with water; a small amount of water to change the oil, but the reason is likely to make such a large amount of water system. Even if a large amount of air into the improper operation, also can not make the system contains such large amounts of water, before the first to find out the reason, in addition to water, water removing moisture in the system that has several times more than that, in addition to water were grams, so the high pressure pipeline water leaks into the possibility, but the refrigerant pressure up to14~15kg and the cooling water only 7kg (water making machine work), water can not leak into the system, but this is the only possible reason. After the winter to refrigerator had stopped for a period of time, this will not be able to restart after the normal operation, it became clear that several times before condenser repair after damage simply did not change under the new circumstances, during that time the condenser is again bad leak, the high-pressure refrigerant pipe leakage, due to stoprunning without inspection, no know, when the pressure inside the pipe is equal to or lower than the pressure of cooling water, water will flow directly into the refrigerant piping system. During the voyage, the water making machine operates, and the water making machine and the refrigerating system are used together with the daily sea water. As a result, sea water pressure rises. And because of the operation of the water dispenser, about two daily seawater pumps operate simultaneously to achieve vacuum pumping capacity, but if the cooling system, condenser, cooling water inlet valve are completely closed, the pressure of the sea water is too high. For more than a decade, the corroded sea water pipeline is often broken, the pressure is too high, I am afraid the pipeline rupture, so the sea water flows through the condenser, so that a large number of sea water into the system. So the system is for the air conditioning service, evaporation temperature from -5 DEG C, R22 water soluble ability especially high temperature water soluble ability is higher, so the system has a small amount of water will not lead to ice jam, so running after the suction pressure decreases quickly, we have not thought of pipeline is blocked, is caused by the ice plug, if so you can judge a lot of water into the system, but it is simply assumed to be caused by the leakage of refrigerant because, resulting in more serious consequences later. Because of the large amount of water vapor and lubricating oil mixed with refrigerant, the compressor load is increased,Consequently, the suction valve is damaged and the suction chamber is switched on when the compressor is working, and the suction pressure rises rapidly. And because the water coolant and blending, blocking the increase of pressure, corrosionresistance increases, the system of pipeline corrosion and spalling of impurities into the refrigerant and lubricating oil, the oil rapidly deteriorated, occlusion pressure meter and relay pressure tube, hydraulic valve block unloading mechanism of pipeline, the oil distributor paralysis, gear pump gear broken series;4.2 brief introduction: when the system fault mechanism in water, the water content has far exceeded the Freon R22 solubility, expansion valve and after a period in the temperature drop below zero, then there will be a part of the free water into small ice crystals, which increases with time, the ice will be more and more, R22 solubility in 30 DEG C the 1 470mk / kg, so the system of water enough to expand to the ice ice jam, and because of cold water and Xiangrong after exfoliation corrosion of the expansion valve dirty block, but also because of dirty oil makes the oil pressure unloading mechanism of paralysis, pressure relay failure and the compressor cannot start unloading, and because the refrigerant suction valve and the pipeline problem caused by startup of "Ben oil" in the system, save more oil, and suction filter, dryer / filter dirty high-pressure pipeline blocking in the short time, after the compressor start and stop (low suction effect). ;In order to eliminate the large amount of water, oil and dirty block, the system should be evacuated. Remove the metamorphic oil before taking off. Turn off the suction stop valve, start the compressor and vacuum the crankcase to recover the refrigerant dissolved in the oil. Then stop the compressor and turn off the drain valve. Then you can loosen the oil drain cock,blow off the dirty oil, remove the crankcase side cover, clean the crankcase and wipe it off with a clean cloth. At the same time will remove the cylinder head cover, remove the suction and exhaust valve, check valve and damaged spring, new spring, new valve, suction valve device, to clamp ring fixed in the valve body, with a special compression spring copper, in order to ensure the ring position is installed correctly, check whether the manual turning crank normal, check whether the crankcase completely clean and dry, and then the side cover and drain plug device reset. When finished, pour clean oil from the filler. After the lubrication is finished, the manifold of the exhaust stop valve is used to start the atmosphere. When the compressor is started, the air in the crankcase is drawn out until the crankcase reaches a steady vacuum. The utility model closes the multipurpose passage and stops the compressor. After the gas pressure gauge and pressure relay tube removed, dredging or renewed attention, refitted slightly open valve will exclude air stored in pipe and the cavity, after the completion of the work on the system time, exhaust and drainage.Time, compressor, practice: slightly open the compressor suction valve, close the discharge valve, open the drain valve mostly evacuated by channel; each valve closing system in the atmosphere (such as filling agent, valve, vent valve etc.); open system in the rest of the valve includes a bypass valve. The cooling water in the condenser is exhausted so as to accelerate the evaporation of the water. The compressor on the minimum energy position, when the system has reached a stable vacuum, and the outlet feel gas is discharged off the compressor suction valve, and then hand hold out valve with multiple channels,Open the valve quickly, remove the stop valve, turn off the multi-purpose channel, stop, install and reuse the channel plug and then stop. After the end of time can check the tightness of the vacuum system, sufficient to meet the requirements of 93Kpa 8h in freon, no vacuum pressure drop is 1Kpa, it can meet the requirements of.After the troubleshooting, restart the system, but because the system refrigerant leak a large number of refrigerant is obviously insufficient, must be re injected refrigerant. Before starting in the upper reservoir gas off the liquid outlet valve, accumulator compressor, the refrigerant system with non condensable pressure together into the condenser, and then stop the compressor; continue to supply cooling water to condenser, refrigerant condensation condenser pressure fully, until no longer fall so far, then vent valve opens the top of the condenser, let the aggregation of non condensable gas outflow in the upper part of the condenser, a few seconds after closed, stop for a while and repeat the operation, in order to reduce the disturbance, reduce the loss of refrigerant. After each bleed, note that the pressure gauge is discharged and the pressure placed in the condenser is close to the saturation pressure of the water temperature, and the operation of releasing air should be finished. Start filling agent will take over and the steel pipe connected, filling agent before the cylinder valve slightly open out the air tube, the other end is connected in a desiccator before filling agent valve, screw, open the cylinder valve to charge refrigerant into the system, when the pressure balance and pressure cylinder, the cylinder can start the compressor open the outlet valve. Directly to thesystem filled with refrigerant refrigerant evaporated in the evaporator, the compressor, and the condenser after the pump reservoir. This system takes R22 about 120Kg, according to the estimated dose enough charge weighing, close the cylinder outlet valve, open the outlet valve of the reservoir, so that the operation of the compressor for a period of time, such as the reservoir can keep 1 / 3 above level can stop filling, open in front of the tube with hot water heating tube filling agent, the liquid state the evaporation of the refrigerant enters the system charge valve shut, remove the filler pipe to reduce the waste of refrigerant, began to normal operation, should pay attention to the dryer / filter ends have obvious difference, such as the temperature that have been blocked, the dryer for new, because of a large number of new refrigerant filling into more after water, in order to avoid the fault of compressor running again, after a period of time will be renewed for the new dryer, avoid air mixing system. After the above operation, the system has been running normally, but because the condenser damage caused by so serious accidents, wasting a lot of material, so the workload is greatly increased, and the air conditioning days cannot run, this kind of accident is worth pondering.。