In this paper, effects of the number of the layers on the separation characteristics of the wire-mesh demister is described. The wire-mesh demister used here is constructed with galvanized iron wires 850μm in diameter, and is held perpendicular to the vertical upward flow of air laden with water droplets. Experiments have been made with mesh layers from one to four layers and for mean air velocity from 0.5 to 4.0 m/s. In the case of the vertical upward air flow, the water-film on the wire-mesh surface has important influences on the size distribution of water droplets, the separation efficiency and the pressure loss coefficient. Obtained separation performances are compared with the results predicted by theoretical analysis which has been presented before.
In the latest progress on the ship's automation and man-saving, request of reliability for ship equipments increase more and more, but marine accidents are occuring frequently at present. This report aims at giving the generally tendency and peculiarity of machinery failures classified into 4 groups. Field data are collected from the Judgement Document of Marine Inquiry Agencies and stored as database by the personal computer. Results of these analysis are as follows. 1. Machinery accidents and damages occupy about 17% in the all of marine accidents by the year. 2. Fishing boats take the greater number of accidents in each group, and cargo boats follow. Cargo boats accidents remarkably decrease in the group of younger generation. 3. Ships under 200 tonnage share about 78% of total ships. 4. Machinery accidents at the calm sea share over 80% of the total. Machinery accidents have also characteristic by each generation in the group.
Fish oil has been made above 400, 000 ton in a year as by-product on mealing process. The engine tests were carried out with several mixing ratios of fuel between fish oil and diesel oil on a small high speed diesel engine with direct injection chamber. The results obtained from combustion analysis were not influenced by the mixing ratio of fish oil on combustion characteristics such as ignition delay. heat release rate diagram and so on. Still, smoke had a maximum value when the mixing ratio was half on low load operations. The period of starting up was longer with increasing the mixing ratio. Piston ring wear and carbon deposit in combustion chamber were increased with the mixing ratio on the continuos operation test. And also lubriating oil showed the deterioration at some properties by using the fuel blended fish oil. One of this reason was a fuel dilution into the lubricating oil. These appearances were more notable with making the mixing ratio larger. It was showed that the combustion performance of fish oil could sufficiently adapted as fuel substitute for the diesel engine. The cetane number of fish oil is seemed the same that of the diesel oil. However engine is influenced by means of fish oil when the long continuous operation so that it needs the cares to avoid troubles in practical use of it.
In case of fishing and training vessel, electric equipments are more than that of the similer sizes' merchant ship. When the value of diversity factor is overestimated and underestimated, estimated necessary power and practical necessary power differ remarkably from each other in value, for this reason, generator has engine trouble. Therefore, diversity factor is factor that produces an great effect on the estimated necessary power. As the estimated necessary power must be grasped accurately, we researched, here the operating condition of automatic start-stop machines and electric power consumptions for the conditions of summer navigation, winter navigation, fishing and mooring on experiment vessel. we came to the following conclusions; 1) we are apt to adopt excessive value of the diversity factor (%) on the fishing and training vessel. There is not a difference of value under the various operating conditions, and as a value of that, we recommend the use of 35%, where; Diversity Factor (%) =Maximum required electrical power/Sum of maximun required electrical power of each intermittent service load×100 [%] 2) There is not a very difference of load factor under the various operating conditions, and as a value of that, we recommend the use of 65%, 3) As such the fluctuations in the necessary power during a day can not be found easily, we can apply the method that estimate the necessary power, the same method as a merchant ship uses, it is the method which convert the total of intermittent load in continuous load using diversity factor.
Sea bottom sludge which is polluted by toxic matters is widely sedimented in closed water area. The sludge is usually disposed of in containment area. The treatment of sludge is regulated by law when it contains toxic matters. For the practical enforcement of regulation, it becomes hard to obtain adequate large continment area. This paper describe the flotation method to separate toxic matter -paint containing PCB- from the sludge. Flotation method is applied in mining to concentrate metal components from crushed ore. Experiments were carried out to separate paint particles from sea water. Flotation of paint from sea water were measured with various reagent, pH values and flotation time. From these results, it was found that DBS is a useful reagent, and optimum pH value and reasonable flotation time were obtained. Further experimets to obtain design data for practical model equipment will be required.