Design and experiments of the sectioning device for the fresh Monopterus albus

Abstract: Fresh water products is one of the most valuable nutrients in nature, due to the high protein content rich in amino acids and vitamins. Among them, the Asian swamp eel (Monopterus albus) is one of the most widely distributed freshwater fish in China. However, a great challenge is still remained in the aquatic products processing, due mainly to the manual sectioning with high labor intensity, low work efficiency and low safety, particularly for the Monopterus albus and pond loach (Misgurnus anguillicaudatus) freshwater fish. Taking the fresh Monopterus albus as the test object, this study aims to design and develop a new sectioning device, according to the fish habits and body characteristics. A series of experiments were carried out to determine the fish body clamping and force characteristics, in order to analyze the fish feeding, body positioning and clamping behavior. The sectioning device was composed of the tilting hopper, fish inlet channel, counter roller, and blade disc. Specifically, the structural parameters of the sectioning device were set, where the fish inlet channel was 180 mm long and the diameter at the fish inlet was 28 mm; the edge of the roller was serrated with a wide top and narrow bottom; and the diameter of the blade disc was 114 mm. The influencing factors of the sectioning were selected as the diameter of the roller, the initial gap of the roller, the rotation of the roller, and the exposed height of the blade disc. An optimization test was carried out with the impact factors of roller diameter, roller initial gap, roller rotation speed, and the exposed height of the blade disc as the influencing factors, and the acceptability score of the sectioning as the evaluation index. The results showed that the better clamping performance of the fish body was achieved in the roller diameter of 180 mm. The highest acceptability score of the abdominal section was obtained in the roller initial gap of 8 mm. Furthermore, the clamping performance was significantly better at the high roller rotation speed than that at the low one in the constant roller diameter. The acceptability score of the abdominal section increased gradually with the increase of the exposed height of the fish body support plate by the blade disc. The orthogonal test showed that the highest acceptability score of abdominal dissection was obtained, when the roller rotation rate was 180 r/min, the exposed height of the blade disc to the support surface was 22 mm, and the roller initial gap was 8 mm. The generality test showed that the new section device can be expected to better apply to freshwater fish with different body sizes, fully meeting the actual processing requirements. The optimal production capacity reached 24.3 pieces/min. The finding can also provide a strong reference to developing sectioning devices for freshwater fish.