渦巻ポンプのNPSHに関する調査 : カーゴオイルポンプの吸込性能について

概要

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This report explains the analysis of suction performance of centrifugal pump by introducing the method of Net Positive Suction Head, (called NPSH) generally used in U.S.A.. We made a scheme for suction performance by expressing the following two kinds of NPSH on the pump characteristic curve; namely NPSH available at suction piping apparatus and NPSH required to operate safely without cavitation. We, herewith, are going to report a result of analising the suction performance of cargo oil pump in a tanker by utilizing these schemes. Further, the bore of relief valve can be reasonably determined by NPSH, which is arranged to prevent a rise of temperature in casing at the shut-off condition. However, this problem will be omitted in this report. Firstly we show how to make these schemes. In these schemes, the following factors are shown on one plane; delivery head, suction piping loss, the height of pump installation, required NPSH, vapore pressure of water, delivery resistance. By these schemes, it becomes clear at what point the cavitation begins to occur when the oil level in oil tank decreases. Secondly we illustrate how the characteristics of cargo oil pump change in the following operation; 1. Operating under cavitation. 2. Throttling delivery valve to avoid cavitation. 3. Reducing revolution to avoid cavitation. One example of calculation in an actual oil tanker is described.
社団法人日本船舶海洋工学会の論文
1960-03-31