Study on new joint of penstocks. Suiatsu tekkan no shingata tsugite ni kansuru kenkyu

The field joint method of the penstocks adopts almost welded joints, and welding work form most part of their installation work on site. The mechanical joint method which was developed by Mitsubishi Heavy Industry Co., is called that it abbreviates circumferential welding of the penstocks on site, and is able to reduce installation period by 50% together with construction cost, compared with those of welding method. In order to examine the possibility of its practical utilization, the simulation test under the actual condition to be used was conducted, jointly with Mitsubishi Heavy Industry Co. The tests of the joint research were as follows: watertightness at the water pressure of more than 100 kg/cm{sup 2}, statical low pressure test at the low temperature of {minus} 30-{minus} 70 centigrade, degradiation of rubber packing by sliding test for the period equivalent to 50 years, dynamic axial and dynamic anguler displacement test, creap test for rubber packing, etc. As the results of these tests, the mechanical joint method is understood to be applicable to simplification of the installation work, reduction in construction period and cost, in minor power plants. 11 figs., 2 tabs.