一、概况最早的直接膨胀式制冷系统如图1所示,它由冷凝压力供液。这种系统不容易操作,若调节阀开得小,会因供液不足而引起气体过热,不仅降低了蒸发器的效果,而且使排气温度升高,导致润滑油焦化。若阀门开得过大,则容易引起液击。因此在负荷波动较大的情况下,这样的系统是很难操作和不安全的。 First, an overview The earliest direct expansion refrigeration system shown in Figure 1, it is supplied by the condensing pressure. This system is not easy to operate, if the valve is opened too small, due to lack of fluid supply caused by overheating, not only reduces the effect of the evaporator, but also to the exhaust temperature, resulting in lubricating oil coking. If the valve is too open, it is easy to cause liquid hammer. Therefore, in the case of large load fluctuations, such a system is difficult to operate and unsafe.