1. Field of the Invention
The present invention relates to a condenser wherein as a result of heat exchange between two mediums, one gas medium condenses.
2. Description of the Prior Art
There are various types of condensers, including the plate type and the tube type, but a common problem which arises in improving the heat transfer performance is connected with film coefficient which indicates the ease with which heat transfers on the heat transfer surface. Film coefficient is given by (the thermal conductivity of a liquid film divided by the thickness of the liquid film). Therefore, it is determined by the condition of condensate adhering to the heat transfer surface. When this condition of condensate adhering to the heat transfer surface is considered, it will be seen that a downflow liquid film of condensate is formed on the entire heat transfer surface facing a space into which a gas medium, for example, water vapor to be condensed is fed and that such liquid film gradually grows as condensation continues, until it is carried away by its own weight or by the flow of vapor and flows down along the heat transfer surface. Since this downflow liquid layer blocks the contact between the heat transfer surface and the gas medium and its thickness increases progressively as it approaches the bottom of the heat transfer surface, the film coefficient on said heat transfer surface is greatly decreased, thus considerably lowering the heat transfer performance. Therefore, in order to improve the heat transfer performance of the entire heat transfer surface on which a gas medium condenses, it is necessary to prevent the condensate from growing into a thick liquid film covering the entire heat transfer surface.
As for an arrangement which meets this necessity, a heat transfer surface which is formed with flutes or corrugations is known. In such heat transfer surface construction, on the condensing heat transfer surface facing a space into which one medium, for example, water vapor, to be condensed is fed, said one medium is cooled by the other cooling medium, for example, cooling water, producing a condensate which is then collected in the valleys (as seen from the space for the gas medium to be condensed) of the corrugations on the heat transfer surface by the action of surface tension and flows down these valleys, thus preserving the ridges of the corrugations as heat transfer surface portions not covered with thick condensate films. With this heat transfer surface, the ratio of the area of the condensate film flowing down the heat transfer surface is decreased; conversely; the area of the exposed heat transfer surface portion not covered with a thick condensate film is increased, thus improving the heat transfer performance.