Improvement And Experimental Test Of The Belt-clamp Freshwater Fish Slitter

Based on the belt-clamp freshwater fish slitter produced previously,this research made conclusions about the problems and drawbacks in trial test,analyzed the reasons of the problems in delivering system,slitting system and other parts and a new kind of belt-clamp freshwater fish slitter was designed and tested.The experiments of belt space in delivering system and cutter head height in slitting system were designed to explore the optimal processing parameters of the fish slitter for different specifications of grass carp,bream and carp.The belt space experiments took belt space as factors,feeding success rate and delivering success rate as index.The experiments in the height of cutter head took cutter head height as factors,the retention rate of swim bladder and fish bile,slitting rate and entry point position as index.The results are as followed: the belt spaces were 40 mm,45 mm and 50 mm,when the slitter delivered three scales of grass carp(1.5±0.15 kg,2±0.15 kg and 2.5±0.15 kg),respectively.The belt spaces were 15 mm,20 mm and 25 mm for bream with three scales(0.4±0.1 kg,0.6±0.1 kg and 0.8±0.1 kg),respectively.The belt spaces were 35 mm,40 mm and 45 mm for carp with three scales(1.5±0.15 kg,2±0.15 kg and 2.5±0.15 kg),respectively.Under the optimal belt space,the fish body can be delivered into the belt without slipping or jamming,there was no slipping between delivering belt and transmission rollers,which can improve the continuity and reliability during process.Slitting from the dorsal part of the fish,the slitter can cut fish dorsum with the retention of bladder or bile according to the processing requirements.The cutter head heights were55 mm,60 mm and 65 mm for grass carp in three scales(1.5±0.15 kg,2±0.15 kg and2.5±0.15 kg),respectively,when slit the fish body without hurting the bladder.The cutter head heights were 55 mm,55 mm and 60 mm for bream with three scales(0.4±0.1 kg,0.6±0.1 kg and 0.8±0.1 kg),respectively.The cutter head heights were 70 mm,80 mm and 90 mm for carp with three scales(1.5±0.15 kg,2±0.15 kg and 2.5±0.15 kg),respectively.But the slitting rates were 81.8%,78.2% and 81.6%for grass carp,81.7%,82.5% and 83.6% for bream and 77.4%,77.3% and 74.7% for carp under these heights.The cutter head heights were 40 mm for grass carp in three scales when slit the fish body without hurting the bile.The cutter head heights were 30 mm,35 mm and 35 mm for bream,60 mm,60 mm and 70 mm for carp in three scales,respectively.Under these heights,the slitting rate could be 86.8%,88.1% and 89.7% for grass carp,92.3%,93.0%and 92.9% for bream,83.1%,85.4% and 83.9% for carp,respectively.The cutter head height could affect the slitting rate and entry point noticeably.The higher cutter head heights were,the higher slitting rates and the smaller distance between entry point and fish lip would be obtained,indicating that lower cutter head height should be chosen to slit the fish better.Under the same height,the fish scale had a significant effect on the slitting rate and entry point position.The slitting rate increased and the distance between entry point and fish lip decreased with the fish scale increased.To evaluate the fish-slitting effect on grass carp,bream and carp,a L8(27)orthogonal experiment was arranged,taking slitting loss rate as index,the tooth height of cutter head(A),rotating direction of slitting(B),rotating speed of cutter head(C)and belt speed(D)as factors to study the influence of these factors on fish-slitting effect.The results turned out to be that: for grass carp,the tooth height and rotating speed of cutter head had significant effect on slitting loss rate,rotating direction of slitting,belt speed and the interaction between the factors didn't had noticeable influence on slitting loss rate.The best combination of factors were: 2.5 mm tooth height of cutter head,cutter rotated reversely,with the speed of 2000 r/min and a belt speed of 0.2 m/s.For bream,the tooth height of cutter head had an extremely significant effect on slitting loss rate,rotating speed of cutter head and belt speed had a significant influence on slitting loss rate,while rotating direction of slitting and the interaction between the factors didn't had noticeable influence on slitting loss rate.The best combination of factors were: 0 mm tooth height of cutter head,cutter rotated reversely,with the speed of 2000 r/min and a belt speed of 0.2m/s.For carp,the tooth height of cutter head had a significant effect on slitting loss rate,rotating direction of slitting,rotating speed of cutter head,belt speed and the interactionbetween the factors didn't had noticeable influence on slitting loss rate.The best combination of factors were: 2.5 mm tooth height of cutter head,cutter rotated consequent,with the speed of 2000 r/min and a belt speed of 0.2 m/s.Finally,to evaluate the maximum cutting force while slitting fish body,the cutter shaft torque was measured and maximum cutting force were obtained while slitting grass carp,bream and carp,respectively,which provided reference for the process of freshwater fish equipment.Meanwhile,maximum cutting force tests for different kinds of fish were designed and conducted based on the slitter.The results turned to be that: the maximum cutting force were 156.3N,44.7N and 55.4N for grass carp,bream and carp,respectively,while the cutter head height chose the standard which retained fish bile.The fish bone of grass carp was thicker compared with bream and carp,which needed a lager cutting force.