Sadami Yada

Methods of preventing squid-sucker suction on the collecting chute

本論文では，イカ釣漁船の収集作業におけるシュート内でのイカの吸盤吸着力を低減させるため，吸盤とシュートの接触低減，吸盤内の密閉防止の観点から 3 つの吸着防止方法を提案した。これに基づいた吸着防止方法有（3 方法）および防止方法無のシュートをそれぞれ試作した。これら 4 種類のシュートを用いて活イカの吸盤吸着力，イカ魚体とシュート間の摩擦力，およびその両者を合計した総合的な摩擦力について計測し，評価を行った。この結果より，提案した吸着防止方法の有効性が確認できた。

A New Measuring System of the Cutting Edge Angle for Fresh Fish Knife.

刃物の刃先角度は切れ味を決める重要な要素であり, 刃物の切れ味を把握するためには, 刃先角度を正確に計測する必要がある。本論文では, 光の反射原理を応用した刃先角度を計測するシステムを開発し, その計測精度について検討した。結果の概要は次のとおりである。1. 3種類7本の片刃の刃先角度を計測したところ, 刃物各部の刃先角度は不均一であった。手仕上げ作業が原因と考えられる。2.レーザ光のビーム拡がりによる計測精度への影響は小さく, 実測の誤差は0.1度であった。3.本計測システムの使用により, 刃物の加工工程での抜取り検査が可能となり, 出荷品の均一化に寄与できる。

Study on Roll-type Separative Mechanism for Counting Numbers of Seedling Fry.

A separative roll-type mechanism installed between an automatic fish selector and counting system was devised. The separative state of overlapping fish body was investigated by controlling the peripheral velocity of the first roll on the supply side, and the ratio of peripheral velocities of neighboring rolls, by adjusting the angle of inclination of the line connecting the centers of rolls parallel to each other and the interval distance between neighbor rolls, by controlling the ratio of overlapping fishes body length, and from the relationship between the distance of partitive boards and fish body width. The results were as follows.1. When the ratio of peripheral velocity of neighboring the rolls was 1.00, the peripheral velocity of the first roll was 0.8m/s, and the ratio of overlapping fishes body length was 75%, overlapping fry were perfectly separated.2. When the ratio of peripheral velocity of neighboring rolls was 1.26 and the ratio of overlapping fishes body length was 75%, the separation of overlapping fishes body was not affected by the peripheral velocity of the first roll on the supply side, and the counting error of fry numbers was zero.

Lighting by Fluorescent Lamp in Fishing Boat

The space for acommodation and engine room of a fishing boat are much narrower than those of a merchant ship. Thus it is impossible to install all lighting apparatus on the required position. Judging from ”the recommended levels of illumination” of the Japanese lndustrial Standard, some parts where illuminance are lower than the standard level are found.The heigh frequency operation of the fluorescent lamp. as the countermeasures of increase in the illumination and decrease in the electric power were noted. Likewise, experiments on the fundamental characteristic amd the continuous action performance were conducted to compare the electronic invertor ballast and the conventional coil ballast.The following could be concluded;1) Performance of the fluorescent lamp using invertor ballast was independent of f luctuatuons in the voltage and frequency of power source.2) Luminous flux amd luminous efficiency of the fluorescent lamp using the invertor ballast increased to 18% and 23% respectively, compared with those using coil ballast.3) Each secular change of luminous flux showed approximately a similar decreasing tendency. The extended lifetime of the fluorescent lamp was assumed to be 107 days approximately in consideration of the increased luminous flux within the invertor ballast.4) Saving of running cost using high frequency operation was estimated to be 142, 000 yen per year on a research and training fishing boat.

Electric Power Saving of Cooling Sea Water Pump of Fishing Vessel Using Inverter

Experiments on twe variable discharge systems of cooling sea water pump for main engine and for generator engines were conducted to evaluate the effects of electric power saving. One was a combination of a general purpose inverter, an automatic controller and a pair of temperature sensors, and maintained the required temperature difference of cooling sea water between inlet and outlet of main engine. The other was a combination of the inverter, the controller and a pressure sensor, and maintained the required delivery pressure within cooling sea water pump for generator engines.The results showed that it was possible to control the discharge of these pumps, so that the temperature difference amd delivery pressure were kept constant all the time. These systems could save the electric power consumption. In the case of the cooling sea water pump for main engine, the cost of equipment could be offset from the saving of the running cost in approximately 2 years, also the cooling sea water pump for generator engine, 0.6 years. These were suitable for small-powered pump unit (5.5-7.5 kW ) on fishing vessels, these methods also could be widely introduced to fishery machines.