讨论为提供所需液体流量而开发的技术。其中最早的是采用热虹吸原理的浸没式热交换器，带有一个称为缓冲罐的液体供应罐。这导致了许多由制冷剂气体或系统内部压力驱动的液体泵送系统的发展，这些系统提供了高度的可靠性，除了自动阀之外，没有运动部件，也没有密封件泄漏。在选择泵送系统的类型、泵的尺寸和要循环的液体量时，有许多经济方面的考虑。 文中简要介绍了各种类型的系统、一些应用要求、比较经济性，并对冻结隧道进行了比较案例研究。关键词:制冷、制冷剂、再循环、泵、循环泵、成本、冷冻柜、尺寸。引用:研讨会论文，佐治亚州亚特兰大，1990年

Discusses techniques developed to provide for the required flow of liquid. The earliest of these was the flooded heat exchanger utilising the thermosiphon principle with a liquid supply tank called a surge drum. This led to the development of a number of variations of liquid pumping systems powered by refrigerant gas or system internal pressure, which offered a high degree of reliability in that there were no moving parts, other than the automatic valves, and no seals to leak. There are numerous economic considerations in the selection of the type of pumping system, the size of the pump, and the amount of liquid to be circulated. Brief descriptions of the various types of systems, some application requirements, comparative economics, and a comparison case study for a freezing tunnel are included.KEYWORDS: refrigeration, refrigerants, recirculating, pumps, circulation pumps, costs, freezers, sizing.