Countercurrent exchange

About: Countercurrent exchange is a research topic. Over the lifetime, 2255 publications have been published within this topic receiving 28687 citations. The topic is also known as: Countercurrent exchange.

Preparation method of high-purity bergapten and psoralen

Abstract: The invention relates to a preparation method for separating high-purity bergapten and psoralen from ficus carica by using a high speed countercurrent chromatography method. The method comprises the following steps of: (1) preparing a proper solvent system, and standing still for layering to obtain an upper phase and a lower phase; (2) selecting the upper phase as a fixed phase and the lower phase as a flowing phase; filling a countercurrent chromatograph column with the fixed phase, and regulating the rotating speed of a host to be 600-1,000rpm; pumping the flowing phase into the column with a flowing speed of 0.5-5.0ml/min, and after dynamic balance of the whole system is established, introducing the sample through a sample introduction valve; and (3) receiving a target ingredient according to an ultraviolet spectrum of a detector, and then concentrating and crystallizing to obtain the finished product. The method is suitable for the preparation of various types of high speed countercurrent chromatographs as well as bergapten and psoralen of various contents and has the characteristics of large separation quantity, high recovery rate and simpleness and convenience for operation.

Differential Permeation with Permeate Flow

Abstract: Flow is regarded as being parallel to the inner and outer membrane surfaces, and the flow of each phase is regarded as being concurrent with or countercurrent to the other phase. The chapter describes “plug flow.” The simplest embodiment of a membrane cell is tubular, with the tubeside flow concurrent or countercurrent to the flow outside the tube. The tube may be positioned inside another tube, called a tube in a tube, so that this latter flow is within the annulus. Alternately, the cell may be designed similarly to a shell-and-tube heat exchanger, with flow inside the tubes and on the outside or shell side. The shell-side flow may be strictly parallel to the tubes or also across the tubes, or tube bundle, and directed by the use of baffles and baffle cuts. The simplest embodiment, at least for concurrent flow, is to regard the flow system as a case of perfect mixing at each point of a continuum where the composition varies from point to point of the continuum, as well as the stream rates, from one end to the other.

Regenerative heat exchanger and turbine that incorporates said heat exchanger (Machine-translation by Google Translate, not legally binding)

Abstract: Regenerative heat exchanger and turbine that incorporates said heat exchanger. This heat exchanger is applied to the heat transfer between a flow of hot fluid and of cold fluid, at different pressure and comprises one or more pairs of heat exchange assemblies, with heat sinks in the path of the hot flows and cold and two unique inputs and outputs differentiated and functionally interchangeable by each set, as well as means for selectively feeding, directing and sealing a cold fluid flow and a hot fluid flow, alternately to one or the other of said heat exchange assemblies, said alternation of the flows occurring both in a parallel flow arrangement and in a countercurrent flow arrangement through said heat exchange assemblies. A turbine incorporating said heat exchanger implemented in its operating cycle is also included. (Machine-translation by Google Translate, not legally binding)