扇贝苗分级计数装置的设计与试验

摘要

By analyzing and investigating the system of random sampling for bottom sowing offspring seed ofpatinopecten yessoensis in Dalian Zhangzidao, a new type of high-efficiency and reasonable grading and counting device for scallop seedling was designed. In order to prove the rationality of its structure, comparison tests were executed on the island of Xiao Changshan and the scallop seedlings were collected from this island. Scallop grading specifications were <30, 30−35, >35−40 and≥40 mm. Mesh specifications were 38, 33 and 28 mm. There were 2 phases for the experiment. In the first phase, the orthogonal experiment analyzed the critical influencing factors of grading and counting statistical accuracy, and determined the optimum technological parameters of grading and counting device for scallop seedling. In the second phase, based on actual production situation, the tests lasted for 1 month (from October 5th to November 4th, 2014) and 4 groups of comparative tests were executed in which 1 group of test was executed within 1 week. Each group of test was repeated by 3 times, and each time grading and counting was finished for one box which stored 20 kg scallops. The interval time between each time was one hour. Grading and counting tests were completed by manual labor and machine respectively. At the end of each day, calculate the statistical deviation rate of scallops, the lower activity rate, the total number of workers and the total time. Through optimizing technological parameters of grading and counting device, the input of scallop seedling grading was finally determined to be 2.5 kg/min, the mesh size increment was -2 mm, the screen motor speed was 130 r/min, the angle between screen surface and horizon was 2°, the screen length was 1.2 m, the input of scallop per unit time in counting was 2 kg/min, the queueing baffle positional relationship was that the angle of upper baffle and conveying direction was 45° and the angle of under baffle and conveying direction was 30°, and belt motor speed was 115 r/min. The results showed that the deviation rates of grading and counting between mechanical and manual manner were 2.82%, 2.33%, 2.28% and 2.90% respectively in the 4 tests for the≥40 mm group, 3.05%, 4.26%, 4.38% and 3.66% respectively for the >35−40 mm group, 2.26%, 1.75%, 2.10% and 2.29% respectively for the >30−35 mm group, and 9.04%, 11.44%, 7.63% and 9.23% respectively for the <30 mm group. The deviation rates of grading and counting for the 4 specifications between mechanical and manual manner were not significantly different (P>0.05). Working efficiency of mechanical manner was increased by 3.54 times and employed workers were reduced by 6 compared with manual manner. Labor intensity was significantly reduced, and exposing time of scallop seedling was also reduced, which ensured the activity of bottom sowing scallop seedling. It had remarkable economic benefit, and the grading and counting device for scallop seedling could save investment cost by 62.512 ten thousand yuan per year. This method meets the development needs of green industry.%针对目前底播虾夷扇贝（patinopecten yessoensis）苗种海上抽样分级计数用工量大、劳动强度高、工作效率低以及分级计数误差高等问题，通过对獐子岛虾夷扇贝底播作业模式和抽样分级计数方式的调研，设计了能够适应海上收购、分级计数、底播等要求的贝苗分级计数装置，该装置由分级筛选机构与排队传送计数机构组成，可同时实现4种规格贝苗的分级与计数。试验分2阶段进行，第1阶段分别对影响分级筛选机构分级准确性与排队计数机构统计准确性的因素进行正交试验分析与验证，确定贝苗分级计数装置的最佳工艺参数，其中分级贝苗投入量2.5 kg/min、筛网孔径增量−2 mm、筛网电机转速130 r/min、筛面与水平方向夹角2°、筛网长度1.2 m时分级效果最佳，计数筛选投入量为2 kg/min、排队上档板与传输方向夹角θ1=45°、下档板与传输方向夹角θ2=30°、传动带电机转速为115 r/min时计数效果最佳；第2阶段在小长山岛海区进行海上对比试验，贝苗分级规格从小到大分别为<30、30～35、>35～40、≥40 mm。4次试验中，≥40 mm规格的贝苗机械与人工分级计数的偏差率分别为2.82%±0.19%、2.33%±0.30%、2.28%±0.15%、2.90%±0.11%，>35～40 mm规格贝苗分级计数偏差率分别为3.05%±0.14%、4.26%±0.15%、4.38%±0.19%、3.66%±0.23%，30～35 mm规格贝苗分级计数偏差率分别为2.26%±1.01%、1.75%±1.02%、2.10%±1.39%、2.29%±1.639%，<30 mm贝苗规格分级与计数偏差率分别为9.04%±1.56%、11.44%±1.79%、7.63%±3.03%、9.23%±4.89%，同种规格机械与人工分级计数偏差率差异均不显著（P>0.05）。采用机械分级与计数统计在2人辅助（筛选与计数投苗工作）的情况下，完成20 kg贝苗分级计数所需时间平均为16.9 min，作业效率为0.59 kg/min，为人工作业（每组8人同时工作）效率的4.54倍，且作业人数减少6人，作业强度大幅降低。采用贝苗分级计数装置对贝苗进行抽样分级作业经济效果显著，每次底播期分苗作业(2个月完成0.67亿个贝苗的分级与计数)可节省费用约为62.512万元。由此说明，贝苗分级计数装置具有较好的稳定性，且在提高工作效率、降低劳动强度和增加经济性等方面效果显著，具有推广应用前景。