【 Weak current College 】 refrigeration system failure symptoms (2)

3. exhaust (condensing) pressure variation on the impact of the refrigeration system
Refrigeration system is running, the exhaust gas pressure and correspond to the condensing temperature, and the condensing temperature and cooling medium flow rate and temperature, the refrigerant flows, cold load, etc. To check the cooling system should be in the exhaust tube place put an exhaust pressure gauges, testing, analysis of exhaust pressure as the fault information.
(1) exhaust pressure high factors when exhaust pressure higher than the normal value, generally are cooling medium flow small or cooling medium temperature is high, the refrigerant charge too much, cold load big and large expansive open.
Above factors may cause system cycle traffic increases, the condensation heat load increases. Due to heat not all bulk out in time, cause condensation temperature to rise, and can detect the exhaust (condensing) pressure rise. In the cooling medium flow, low or high temperature of the cooling medium, condenser cooling efficiency reduces the condensing temperature rise. In the cooling medium flow, low or high temperature of the cooling medium, condenser cooling efficiency reduces the condensing temperature rise. For refrigerant charge too much, excess refrigerant fluid in occupies part of the condensate pipe so that condensation area declined, causing condensation temperature rise.
(2) exhaust pressure lower than normal exhaust pressure factors, its elements have compressor efficiency low, refrigerant quantity, cooled load, expansion valve to open degree, filters are not clear, including the expansion valve strainer and cooling medium temperature is low, and so on.
The above factors will lead to reduction of refrigerant flow system, cooling load for the condensing temperature drop.
From the suction pressure and exhaust pressure changes with exhaust pressure, there is a close relationship. In General, the inlet pressure, discharge pressure also increased; inhalation pressure drops, exhaust pressure correspondingly reduced. You can also change from suction pressure gauge of exhaust pressure.
4. inlet temperature and outlet temperature
In practice the system of exhaust temperature and suction temperature very closely. Suction temperature, exhaust gas temperature is relatively high, while low. Find out their relationship can be a very good grasp and control them, so that the refrigeration system run better.
5. compressor condensing unit for temperature variation on the impact of the refrigeration system
Unit parts for temperature has a normal temperature range, beyond the scope of the abnormal state. These abnormal factors may be faulty or adjustment is not correct, but the reason you want to analyze it, and in a timely manner or check. These temperature thermometer measurement point is difficult to use, typically can only feel to estimate, and then determine whether the normal.
(1) exhaust temperatures in summer, the compressor discharge temperature is relatively high hand cannot touch. According to the national standard, the R22 refrigerant system exhaust temperature should not be longer than 150OC, over this temperature line in the case of an abnormal condition. Exhaust temperature ultra-high reasons, is the compressor suction temperature ultra-high or condensing temperature ultra-high, need attention. Exhaust temperature is too low, hands trying to find out the pipe is not hot, particularly low suction temperature, the compressor can run wet trip or system of relatively few in the running state. Compressor wet travel easily damaged valve structure; refrigerants-run less, affect the motor winding thermal, accelerated ageing of insulation materials.
(2) of the enclosure temperature variation on the compressor and refrigeration system of hermetic reciprocating piston compressor casing surface temperature can be divided into two parts: a. by inhalation of vapors on the enclosure, the temperature is relatively low, at the micro or cooler ranges around the estimates in the 30OC, suction-line around the local shell surface of dew. B. under the heat inside the motor casing and was frozen oil out of the heat of friction, mainly by the steam out of the enclosure.
1) enclosure temperature is too high and the reasons for the enclosure surface temperature exceeds the normal range, mainly refrigeration system suction temperature is too high (above 15OC). Excessive heat steam into the compressor, absorbing the heat inside the casing, the vapour temperature higher so that the enclosure's temperature to rise. Superheated steam temperature to rise very high, the enclosure's temperature will rise too high, the oil cooling, which would affect the movement of parts lubrication, accelerated wear and deform bearing axle (killed). It also causes exhaust temperature rise.
2) enclosure temperature is too low and the causes of the enclosure surface temperature is below the normal range, suction temperature too low (below 15OC). Its refrigeration oil and motor windings is beneficial for cooling, refrigeration capacity declined. Particularly low when the suction temperature makes the most of only the enclosure dew, there is a risk of liquid hammer, this is a fatal blow to compressor, particular attention should be paid. While frozen oil dissolved a large amount of refrigerant, is not conducive to moving parts of lubrication.
(3) the temperature condition condenser
1) condenser temperature condition in a normal situation is that the first part of the heat pipe was hot, and its temperature is slowly slowly declining balance of power. Latter part of the heat pipe of the heat level compared with the first part of a larger decrease, since the latter half of the refrigerant inside the tube has been progressively liquefaction, has reached the condensing temperature and cold temperatures. When an abnormal situation, one is the first part is not too hot, the second part is close to room temperature (temperature), the compressor suction letter when wet steam or refrigerant quantity of refrigerant. Another is the condensation pipe is very hot, because of the refrigerant volume too much or little ventilation rate, or the ambient temperature is high.
2) water-cooled condenser shell condenser of shell in normal circumstances is half hot bottom half is warm. Abnormal condition is the entire shell is not too hot, the reason for this is the amount of the refrigerant. Another case is when the entire shell are very hot due to insufficient cooling water or cooling (tube fouling). Tube condenser under normal circumstances, casing looks very hot, because of the cooling water is too small or thermal effects; another I is the entire outer surface of the casing is not too hot, the reason for this is the amount of the refrigerant.
(4) liquid temperature conditions under normal circumstances, suction pipe touch feeling very cold and knot with dew. Because of the poor, the condenser thermal condensing temperature and sufficient quantity of refrigerant high orNote too much.
(5) liquid pipe temperature conditions under normal conditions, liquid pipe as heat. Not normally, hot liquid pipe. The reason is poor, the condenser thermal condensing temperature too high or refrigerant flow.
(6) the filter temperature conditions of basic conditions and infusion tubes are the same, but it has a prominent anomalies, is the filter might be cool because filter mesh be blocked so that the filter sludge is not clear when the refrigerant flow strainer when throttling phenomenon, that is part of the liquid heat absorption, so that the filter gasification sent cool, critical of the dew. Another anomaly is filter not hot, and the ambient temperature is the filter completely blocking the flow of refrigerant cannot.
(7) the temperature of the suction pipe condition normally, suction pipe touch feeling very cold and knot with dew. Not normally, one is a suction-line colder, dew too much to cause condensation on the chassis of the large area. Because the refrigerant flow is too large, liquid cannot evaporator full gasification, liquid reflow phenomenon. Its harmfulness is the compressor has the potential to run wet stroke, serious produces hydraulic hammer, valve plate under threat. The second is a suction-line is not cold, condensation, the enclosure is hot. The reason is the refrigerant flow is too small or the amount of the refrigerant. The consequence is that the exhaust temperature rise, the cooling capacity decrease.