The freezing frame of the high and low temperature impact test box in the initial single-door refrigerator can be clearly seen, and the fin tube like the cooler can be seen when the lining of the frost-free refrigerator is disassembled; the throttle valve is behind the refrigerator A thin copper tube wound into a spiral is a capillary tube. The outer shell of the refrigerator is quite the same as the outer body of the cold storage.
In the refrigeration industry, the refrigerant can be water, ammonia, F12, F22, F502, liquid nitrogen, etc. Lithium bromide absorption chillers for air conditioning use water as a refrigerant. F12 is used in the refrigerator, and liquid ammonia (not ammonia water) is used in the refrigeration system of the large refrigerator. The properties of liquid ammonia can be found on the physical performance table of ammonia. Its evaporation temperature at one atmospheric pressure is- 33.3 ° C. If liquid ammonia is released from a steel cylinder at normal temperature, it will immediately become liquid ammonia at -33.3 ℃ (because the outside is an atmospheric pressure) once it is out of the cylinder. The heat of the ground is transferred to the liquid ammonia, which evaporates the liquid ammonia into vaporous ammonia, and the local part of the cement floor quickly drops to about -30 ℃. If the liquid ammonia flowing on the cement floor is exactly one kilogram, all the liquid ammonia To evaporate light, he must absorb 326 calories of heat from the cement floor. As much as he absorbs and evaporates, if there is less than 326 calories, there must be liquid ammonia remaining.
If the liquid ammonia is placed in a metal basin, and then the bottom of the metal basin is in contact with the water surface, the heat of the water is immediately transferred to the liquid ammonia, the liquid ammonia is heated and boiled, and the water freezes quickly; The air is immediately cooled by the heat transferred to the liquid ammonia and loses heat. The cooled air is falling, and the surrounding hot air is immediately replenished. Below the basin, you can see the cold air with fog slowly descending.
Now let's talk about the cooling process in the high and low temperature impact test box: if liquid ammonia is in the evaporator (drain) at a pressure of 0.3Kg / CM2 gauge (it should be 0.03Mpa gauge pressure, Kg / CM2), its boiling temperature should be ï¼28 ℃; and outside the evaporator is a cold storage of -18 ℃, if there is a commodity higher than -18 ℃ into the warehouse, the heat in the commodity is quickly transferred to the air, making the air temperature The temperature rises to, for example, -15 ℃, and the air at -15 ℃ transfers the heat from the commodity to liquid ammonia at -28 ℃. The temperature absorbed by the liquid ammonia does not rise, but boils and evaporates into a gas (ammonia steam ), So that the air is transferred back and forth, the heat in the goods is gradually reduced, the temperature is gradually reduced, and finally dropped to -18 ℃, the refrigeration can be ended, this is the task of the evaporator (refrigeration and dehumidification).
About Shanghai Linpin Instrument Co., Ltd.
Shanghai Linpin Instrument Co., Ltd. is located in Shanghai Minhang Economic and Technological Development Zone with convenient transportation and developed information. It is a professional company engaged in research, development, manufacturing and sales of environmental test equipment. With advanced equipment, complete testing methods, and first-class technical and management talents, the company's products have always been in a leading position among peers. The products have been widely used in scientific research, electrical engineering, electronics, military, aviation, shipping, post and telecommunications, automobiles, motorcycles and other enterprises and institutions, and provide various technical parameters corresponding to GB, IEC, DIN and other standards. .
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