The evaporator is a device in which the refrigerant exchanges heat with the cooled medium. e liquid vaporizer Can be divided into two categories, e liquid vaporizer namely the cooling of the liquid evaporator and cooling air evaporator.
Cooling liquid evaporator Commonly used in the central air conditioning cold source of the cooling liquid evaporator has two types, namely horizontal shell and tube evaporator and dry evaporator.
Horizontal shell and tube evaporator is used to cool the evaporator such as water and other liquid refrigerant.
Horizontal shell and tube evaporator shell is made of steel plate, welded at both ends of the tube plate, tube plate with expansion or welding method of steel pipe or tube tube tube fixed on the tube board. Both ends of the end cap on the design of a partition. The refrigerant flows in the tube, and the refrigerant flows between the shells. Refrigerant to reciprocate in the evaporator several times, e liquid vaporizer the general process of 4 to 8 times, in order to achieve full heat exchange with the refrigerant asked. The inlet and outlet of the refrigerant are provided on the same end cover, and the refrigerant enters from below the end cap and flows from above the end cap.
After the throttled low-temperature low-pressure liquid refrigerant, from the lower part of the evaporator into the refrigerant surface filled with most of the space within the evaporator, usually the liquid surface stability in the shell 70% to 80%. Therefore, the horizontal shell and tube evaporator, e liquid vaporizer also known as full-liquid evaporator. In the work of the liquid surface only exposed 1 to 3 rows of refrigerant pipes, so that the formation of refrigerant gas vapor continue to rise to the surface, e liquid vaporizer through the top of the gas chamber (also known as liquid separation package, separated from the vapor may The droplets that are entrapped and the refrigerant vapor in the dry state are sucked back by the compressor.
Horizontal shell and tube evaporator using freon as refrigerant, the use of copper tube as a refrigerant pipe, the average heat transfer temperature difference of 4 ~ 8 ℃, heat transfer coefficient of 465 ~ 523 w / (m2 · ℃) The Refrigerant in the pipeline flow rate is generally 1 ~ 2.5 m / s. Compared with the condenser, e liquid vaporizer the evaporator heat transfer coefficient to be smaller.
After the throttling of the low-temperature low-pressure refrigerant liquid, from the lower part of the front cover into the evaporator in the pipeline, after four processes, e liquid vaporizer into a saturated saturated vapor from the top cover by the compressor suction back.
The refrigerant is fed from one end of the housing and flows from the other end. In order to improve the flow rate to enhance heat transfer, e liquid vaporizer in the evaporator shell with a number of rounds of the baffle plate. All baffles are fixed with three rods, with equal length sleeves on the drawbars between adjacent two baffles to ensure that the baffles are spaced.
Compared with the horizontal shell and tube evaporator, e liquid vaporizer dry evaporator refrigerant charge less, generally can reduce 80% to 85%. The refrigerant is called a dry evaporator because there is no free liquid in the evaporation process.