Design and optimization of a head-to-tail orientation device for freshwater fry

Abstract

The head-to-tail orientation is an important part of the automatic injection of fish vaccines. However, it is characterized by being labour-intensive, with a poor working environment and low working efficiency. To solve the above mentioned problems, a freshwater fry head-to-tail orientation device has been designed. This paper took grass carp fry as the object of the study, described the working principle of the liquid bridge, analyzed the forces at key stages, measured the length and bending radius of the fry, and clarified the main factors affecting the efficiency of orientation. With roller radius, conveyor speed, and inclination angle as test factors and orientation success rate as the test index, single factor analysis and orthogonal testing were carried out on the orientation device to study the influence of each parameter on the test index. The optimal parameter combination was obtained. The test results showed that the highest orientation success rate was achieved when the drum radius was 50 mm, the line speed was 0.8 m/s, and the inclination of the conveyor belt was −6°. The orientation mechanism was experimentally verified with this combination of parameters, and the orientation success rate was 99.5 %. The device was simple in structure and could meet the requirements of the head-to-tail orientation of the mechanized injection of fish fry. It provided a reference and the basis for designing the head-to-tail orientation device for a freshwater fish fry.