Commercial flake ice maker tons free design for water pretreatment

Some customers have reported that the ice machine sometimes has operational problems because of refrigerant leakage. Let’s look at several refrigerant leak detection methods.1. Visual inspection: When oil stains are found somewhere in the system, this may be a leakage point. There is a big defect. Unless the system suddenly breaks and the system leaks a large leak and the system leaks liquid colored media, the visual leak cannot be located because the leak is usually very small, and many parts of the refrigeration system are almost invisible.2. bubble water or soapy water leak detection: Fill the system with 10-20kg/cM2 pressure nitrogen, and then apply soapy water to all parts of the system. The bubbling point is the leakage point. This method is the most common leak detection method for maintenance workers, but the human arm is limited, the human vision is limited, and in many cases the leak is not seen at all.3. Leak detection with nitrogen water: Fill the system with 10-20kg/cm2 pressure nitrogen, immerse the system in water, and the bubbling point is the leakage point. The obvious shortcomings of this method: the water used for leak detection is easy to enter the system, causing the materials in the system to be corroded. At the same time, high-pressure gas may also cause greater damage to the system, and the labor intensity for leak detection is also great.4. Fluorescence leak detection: It uses the principle that fluorescent leak detection agent emits bright yellow and green light under the irradiation of ultraviolet/blue leak detection lamp to detect fluid leakage in various systems. When in use, only a certain proportion of fluorescent agent is added to the system. After the system operates for 20 minutes, wear special glasses and illuminate the outside of the system with a leak detection lamp. The leak will show yellow fluorescence.5. Gas differential pressure leak detection: Using the pressure difference between the inside and outside of the system, the pressure difference is amplified by the sensor, and the leak detection result is expressed in the form of digital or sound or electronic signals. This method can only "qualitatively" know whether the system is leaking, but cannot accurately find the leak.6.Halogen lamp leak detection: Ignite the leak detection lamp and hold the air tube on the halogen lamp. When the nozzle is close to the leaking part of the system, the flame color changes to purple blue, which indicates that there is a large amount of leakage. In this way, open flames are generated, which is not only dangerous, but the combination of open flames and refrigerants will produce harmful gases, and it is also difficult to accurately locate leaks. So this method is hardly used by anyone now.7. Electronic leak detector for leak detection: Electronic leak detector is a reliable leak detector. Because of its accuracy in leak detection, it has quickly occupied the market in recent years. When using it, move the probe against the place where leakage is possible. When leak detection When the device sounds an alarm, it indicates that there is a leak. Leak detection with an electronic leak detector is currently the most scientific, simple and fast leak detection method. 

In the ice making machine industry, ammonia refrigeration and fluorine refrigeration have always been the focus of controversy. The choice of refrigeration method can maximize the economic, environmental and social benefits. This article objectively analyzes the nature of ammonia, fluorine refrigerants and ammonia and fluorine refrigeration systems, and summarizes the application status, existing problems, and research directions of the two refrigeration methods in the industry, which will help people have a clear understanding of these two refrigeration methods. To understanding.1. Comparison of properties of ammonia refrigerant (R717) and fluorine refrigerant (R22 and R404A)In terms of safety: the explosiveness and toxicity of ammonia greatly limit its application, and with the frequent news of ammonia refrigeration systems in recent years, people have a certain fear of ammonia refrigeration systems. The high safety of fluorine refrigerants is the main reason for the rapid development of fluorine refrigeration systems in recent years.Environmental protection: ODP of ammonia is zero, and GWP is also zero. R404A is a more environmentally friendly refrigerant, and R22 refrigerant due to its poor environmental performance, developing countries will restrict its application before 2020. At present, people in the industry are actively looking for alternative refrigerants that are more environmentally friendly.Material compatibility: When ammonia contains moisture, it is corrosive to copper. Therefore, copper and copper alloys cannot be used for the pipes and valves of the ammonia system. There are certain limitations in the selection of system equipment materials. Fluorine refrigerants have high chemical and thermal stability, and theoretically they are not corrosive to all metals. Interaction with water: the allowable water content of ammonia is less than 0.2%. Because ammonia is easily soluble in water, even if there is a trace amount of water, it will not appear "ice plug" like Freon, so it is necessary to dry the ammonia refrigeration system to the pipeline system. The requirements are not as strict as Freon. Freon is difficult to dissolve in water, so if there is water in the system, it is easy to cause ice clogging. Usually we have a filter drier in the system. Interaction with oil: At present, the lubricating oil of ammonia refrigeration system is mineral oil, which cannot be miscible with ammonia. Equipment such as oil separator and oil collector are usually installed to return the lubricating oil to the compressor through automatic or manual control. R404A is not miscible with mineral oil and alkylbenzene oil, but it can be miscible with polyester oil (POE). However, at high temperatures (around 50°C), there will be insoluble stratification, and R22 is also slightly soluble in lubricating oil. Therefore, large-scale fluorine refrigeration systems are usually equipped with oil and oil reservoirs. Take R404A as an example. The difference between the two compressors is only the refrigerant. Compare the cooling capacity of R717, R22 and R404A under the same evaporating temperature (-10°C), condensation temperature (45°C), liquid subcooling (0K) and suction superheating (10K). Ammonia has more advantages than fluorine in terms of cooling capacity, COP, and mass flow. However, the exhaust temperature of R717 is much higher than that of R22 and R404A, which will increase the configuration requirements of system components. Ammonia has a much larger refrigeration capacity per unit mass of fluorine, indicating that ammonia has a better refrigeration capacity. However, when the evaporation temperature reaches -33.33℃, the gauge pressure of ammonia is 0. In order to avoid the system working under negative pressure, ammonia is generally used For systems where the evaporation temperature is above -33.33°C.2. System complexityTube ice machine Ammonia refrigeration is a pump-supply system. Since the mineral lubricating oil used in the ammonia refrigeration system is not miscible with ammonia, the ammonia system is indispensable for oil separators, oil collectors and other equipment to ensure the oil return of the system and reduce the system temperature, so that the ammonia The oil system is very complicated. These make the ammonia system huge, many auxiliary machines, complicated pipelines, many valves, complicated construction, and long construction period. The fluorine system has a compact structure, a small footprint, and few accessories. The configuration of the unit has been very complete, and most of it can be completed in the factory of the unit supplier.3. Equipment investmentThe ammonia system includes a lot of equipment, mainly including compressors, evaporators, condensers, oil separators, high and low pressure storage tanks, intercoolers, recoolers, ammonia separators, low pressure circulation tanks, and emergency ammonia discharge devices. , Air vent, oil collector, ammonia pump and corresponding valve parts and bypass valve, etc., resulting in a lot of on-site installation workload. The main equipment of the fluorine system includes compressors, evaporators, condensers, oil separators, oil collectors, gas-liquid separators, liquid reservoirs and corresponding valves, etc. Generally, the fluorine system uses copper pipes or steel pipes, which is convenient to take over. , The pipe layout is simple, and the pipe consumption is less than that of the ammonia system. The cost of investment in ammonia and fluorine refrigeration equipment is at the same level of equipment quality and control methods. For small cold storage (compressors less than 50Hp), the price of fluorine is more than 10% lower than that of ammonia equipment. The prices of large and medium-sized cold storages are almost the same. If imported or imported domestically assembled fluorine refrigeration equipment is used, it is more than 30% cheaper than imported ammonia refrigeration equipment, but 20%-30% more expensive than domestic ammonia refrigeration equipment.4. Degree of automationBecause the valves of the domestic ammonia system are affected by valve material, processing equipment and processing technology, the leakage problem of the valves of the ammonia system is serious, and it is difficult to achieve a high degree of automatic control. Specialized personnel are required for 24-hour management (Note: There are also automated ammonia storages, but they are relatively few). The fluorine system is easy to realize highly integrated and relatively stable automatic control due to the mature products and stable performance of various components, and basically realizes the unattended operation of the system. Due to the hazards of Freon refrigerants to the atmospheric environment, the use of fluorine refrigeration has been restricted in recent years. Therefore, actively looking for more ideal refrigerants is the development direction of fluorine refrigeration. People have made positive progress in the search for alternative refrigerants of Freon. Some experts and scholars pointed out that the better refrigerants to replace R22 are R407C, R410A and R32.ConclusionA comparative analysis of the advantages and disadvantages of ammonia and fluorine refrigerants from the characteristics of refrigerants and current application characteristics shows that ammonia refrigeration has better refrigeration performance, and the toxicity and danger of ammonia are what we have to consider, so we need to continue Research and improve the objective problems of ammonia refrigeration system. The better safety and simplicity of fluorine refrigeration is widely used in small and medium-sized cold storage, and there is also a trend toward large-scale development. However, the hazards of Freon to the atmospheric environment have to be paid attention to. Therefore, it is still to find more ideal refrigerants. The focus and direction of future research.

      The ice making machine cooler is a type of heat exchange equipment used to cool fluids. Water or air is usually used as a coolant to remove heat. Mainly can be divided into tube cooler, plate cooler and air-cooled cooler. When the copper tube of the tube cooler is damaged and leaks, if the tube plug is used to block it, the total number of blockages shall not exceed 10% of the total number of tubes (or according to the requirements of the cooler product manual). According to the water quality and oil quality, carry out the inspection and cleaning of the fouling on the tube wall surface of the tube cooler.      The cleaning method of the tube cooler is as follows:　   1. Cleaning the water side of the tube cooler　   A. Trichloroethylene solution can be used for flushing, so that the cleaning liquid circulates in the cooler. The pressure of the solution is not greater than 0.63MPa, and the flow direction of the solution is preferably opposite to the direction of the oil flow in the cooler. The cleaning time depends on the dirt. After rinsing, introduce clean water into the cleaning until the water flowing out is clean by visual inspection.      B. You can also use carbon tetrachloride soak, pour the solution into the cooler, and watch the color of the solution after 15-20 minutes. If it is severely turbid, replace it with a new solution and repeat the soaking until the color of the solution after soaking is similar to that when it is clean. Then introduce clean water into the cleaning, until the outflow of water is clean by visual inspection.　  C.If there is no obvious structure in the water side pipeline, you can clean it with the corresponding brush according to the diameter of the pipeline, and then rinse it with clean water.　　2. After cleaning the tube cooler, perform a water pressure test. The cavity between the tubes of the tube cooler shall be tested for tightness with water according to its nominal pressure or 1.25 times the working pressure, and the pressure shall be maintained for 30 minutes, and there shall be no leakage at the expanded tube or welded joint. The water must be completely drained after the test.　　3. Check the heat exchange effect of the tube cooler. After the lubricating oil is cooled by the cooler, the temperature can generally be reduced by 5-10℃, and the temperature of the cooling water can be increased by 3-5℃.　　4. The connecting oil ports of the tube cooler must not be opened for no reason during the cleaning process, and must be sealed with bulkheads or flange covers.        Let us understand the difference between the cooler and the condenser of the ice maker:Condenser and cooler are also one of the important parts of heat exchange equipment in the heat exchange process. The main differences between the two are as follows:1. The cooler has no phase change, and the condenser has a phase change but the pipeline entering and exiting the cooler does not change. Generally, the pipe diameter is different from the inlet and the outlet, and the pipe diameter of the inlet and outlet of the condenser changes greatly, which is relatively easy. watch.2. The settings of the baffles of the two are different, the cooler is set up and down, and the condenser is set up and down, and the heat transfer coefficient is also different.3. There will be a liquid level gauge and a liquid level control port on the cooler, but the condenser does not. The air inlet and air outlet of the cooler are both at the upper part of the container and the pipe diameter is basically the same, while the air outlet of the condenser is at the bottom of the container, and the pipe diameter is different from the air inlet. The inlet and outlet of the intercooled ammonia liquid are under the container, while the water inlet and outlet of the condenser are not. The vertical type is generally one up and down, while the horizontal type is at one end of the container. 

      For long-term use of cold storage room, various technical indicators must be checked regularly and adjusted in time. The operating temperature and pressure of the cold storage system, as well as the amount of lubricating oil and refrigerant, must be checked and adjusted in time. The system should have automatic control and compressor alarm devices. Once there is a problem, an alarm will be issued, or an automatic protective shutdown and the compressor will stop. Here are 7 common problems and solutions for the use of cold storage room.      1. The installation environment and maintenance of the air coolerThe location and environment of the air cooler inside the cold storage will affect its operation. Generally, the air cooler near the cold storage door is prone to condensation and frost. Although the air cooler can automatically heat and defrost at regular intervals, if the door is opened too frequently, the opening time is too long, the time and quantity of hot air entering is long, the defrosting effect of the fan is not good. Because the defrosting time of the air cooler cannot be too long, otherwise the cooling time will be relatively shortened, the cooling effect will not be good, and the storage temperature cannot be guaranteed.Kogamaru       2. Drainage of the melted water during the defrosting of the air cooler　　This problem is related to the severity of the frosting. Due to the severe frosting of the fan, a large amount of condensate will inevitably be produced. The fan's drain pan cannot bear it, and the drainage is not smooth, and it will leak and flow to the ground in the warehouse. If there are goods stored below, the goods will be soaked. In this case, a thicker draft tube can be installed to remove the condensate.　　Some air coolers have the problem of blowing water from the fan and spraying it on the stock in the warehouse. This is also the frosting problem of the fan in the cold and heat exchange environment, mainly due to the condensate generated by the fan leaf in the hot environment, rather than the problem of the defrosting effect of the fan itself.　　3.the problem of the condenser fan motor and the electric heating tube of the air cooler　　 This is a vulnerable part. The fan motor that runs for a long time in a high temperature environment may malfunction and be damaged. If the guaranteed temperature of the cold storage is very important, some vulnerable parts should be ordered for timely maintenance.　　4. the ambient temperature of the condenser　　The condenser is generally installed on the roof of an outdoor building. In an environment with a high temperature in summer, the temperature of the condenser itself is very high, which increases the operating pressure of the unit. If there is a lot of hot weather, you can add a pergola on the roof condensation to block the sun and reduce the temperature of the condenser, so as to reduce the pressure of the machine, protect the unit equipment, and ensure the temperature of the cold storage. Of course, if the unit capacity is sufficient to ensure the storage temperature, there is no need to build a pergola.　　　 5. The problem of low compressor efficiency　　 Due to the long-term operation of the compressor, the cylinder liner, piston ring and other parts will be severely worn and the fit clearance will increase. The sealing performance will be correspondingly reduced. The compressor's air delivery coefficient will also be reduced, and the cooling capacity will be reduced. The refrigeration capacity of the compressor can be roughly judged by observing the suction and discharge pressure of the compressor. If the refrigeration capacity of the compressor drops, the common method is to replace the cylinder liner and piston ring of the compressor.　　 6. there is a problem of more air or refrigerated oil in the cold storage evaporatorOnce more refrigerating oil is attached to the inner surface of the heat transfer tube of the cold storage evaporator, its heat transfer coefficient will decrease. Similarly, if there is more air in the heat transfer tube, the heat transfer area of the evaporator will decrease, and its heat transfer coefficient will decrease. The thermal efficiency will also drop significantly, and the temperature drop rate of the warehouse will slow down accordingly. Therefore, in daily operation and maintenance, attention should be paid to timely removing oil stains on the inner surface of the heat transfer tube of the evaporator and exhausting the air in the evaporator.　　7. the cold storage throttle valve is improperly adjusted or blocked, the refrigerant flow is too large or too smallWhen the throttle valve is opened too large, the refrigerant flow is too large, and the evaporating pressure and evaporating temperature will also increase, and the temperature drop rate of the warehouse will slow down; at the same time, when the throttle valve is opened too small or blocked, the refrigerant The flow rate also decreases, the cooling capacity of the system also decreases, and the temperature drop rate of the warehouse will also slow down.　　 Generally, it can be judged whether the refrigerant flow rate of the throttle valve is appropriate by observing the evaporating pressure, evaporating temperature and frosting of the suction pipe. To Clogging is an important factor that affects the flow of refrigerant. The main cause of throttling valve blockage is ice blockage and dirty blockage.　　Ice blockage is due to the poor drying effect of the dryer. The refrigerant contains moisture. When it flows through the throttle valve, the temperature drops below 0°C. The moisture in the refrigerant freezes and blocks the throttle valve hole.　　 Dirty blockage is caused by the accumulation of more dirt on the inlet filter of the throttle valve, and the flow of refrigerant is not smooth, resulting in blockage.