• 한국양식학회지
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• 제18권3호
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• pp.189-195
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• 2005

By testing the separation performance for a fine settleable solid removal system in an aquaculture system using polystyrene particles as an experimental substitute, the optimal geometric dimensions for a Low-Pressure Hydrocyclone (LPH) were obtained. The design approach far the LPH took into consideration two inflow diameters (Di: 30, 50 mm), three overflow diameters (Do: 60, 70, 100 mm) and four cylinder lengths (Lc: 250, 345, 442, 575 mm), while the cylinder diameter (Dc) at 335 mm, the underflow diameter (Du) at 50 mm and the cone angle (${\theta}$) at $68^{\circ}$ were kept constant. The separation performances of 19 different dimension combinations of LPH were tested, ranging from 300 to 1200 ml/sec of inflow rate using substitute polystyrene particles (0.4-0.7 mm dia., ${\rho}_s=1.05g/cm^3$). These polystyrene particles exhibit a similar density and settling velocity to the fine fecal debris of the common carp. The total separation efficiency for the inflow rate ranged from a high of 97% to a low of 20%. Experimental results obtained by ANCOVA and the Tukey test (${\alpha}=0.05$) showed that the separation performances of the LPH were significantly affected (P<0.05) by the fi, Di, Do and Lc. The maximum separation performance was detected at a dimension combination of 30 mm of inflow diameter (Di), 60 mm of overflow diameter (Do), 442 and 575 mm of cylinder length (Lc). The dimension proportions were 0.09, 1.32-1.72, 0.18 and 0.15 for Di/Dc, Lc/Dc, Do/Dc and Du/Dc respectively.

• 한국양식학회지
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• 제18권3호
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• pp.180-188
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• 2005

The separation performances for thirty different dimensions of a low-pressure hydrocyclone (LPH) were tested in order to obtain an optimum dimension scale for fecal solid removal from an aquaculture system. The geometric variables were considered on two inlet diameters (Di: 30 and 50 mm), five overflow diameters (Do: 30, 50, 60, 70 and 100 mm), and three cylinder lengths (Lc: 250, 345 and 442 mm), while the cylinder diameter (Dc) of 335 mm, underflow diameter (Du) of 50 mm and cone angle (${\theta}$) of $68^{\circ}$ were kept constant. A small size for carp feces was regarded as the target for the removal of solids. Spherical polystyrene particles (1.1-1.3 mm dia., ${\rho}_s=1.05g/cm^3$), which demonstrate a similar settling velocity and specific gravity to the carp feces, were used as feed. The separation performance was tested in the range of 330 to 1200 ml/s of the inflow rate. Experimental results using ANCOVA and the Tukey test (${\alpha}=0.05$) demonstrated that the separation performances of LPH were significantly affected (P<0.05) by fi, Di and Do. In contrast, there was no significant Lc effect (P>0.05) on the separation performances. The maximum separation performance was detected at dimension combinations of 30 mm of inflow diameter (Di), 50, 60 and 70 mm of overflow diameter (Do), 345 mm of cylinder length (Lc). The dimension proportions were 0.09, 1.03, 0.15-0.21 and 0.15 (or Di/Dc, Lc/Dc, Do/Dc and Du/Dc, respectively.

• Fisheries and Aquatic Sciences
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• 제13권2호
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• pp.150-156
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• 2010

The separation performance of a low-pressure hydrocyclone (LPH) was evaluated for suspended-solids removal in a recirculating aquaculture system (RAS). The dimensions of the LPH were 335 mm cylinder diameter, 575 mm cylinder height, 60 mm overflow diameter, 50 mm underflow diameter, and $68^{\circ}$ cone angle. The inflow rate varied (400, 600, 800, and 1,000 mL $s^{-1}$) with 25%, 25%, 20%, and 10% of bypass ($R_f$), respectively. The maximum total separation efficiency (Et) and reduced separation efficiency (E't) for suspended solids from the effluent of the second settlement tank (before biofiltration) were 58.9% and 45.2%, respectively, at an inflow rate of 600 mL $s^{-1}$ and 25% of $R_f$. The maximum Et and E't for suspended solids from the water supply channel (after biofiltration) were 24.4% and 16%, respectively, at an inflow rate of 1,000 mL $s^{-1}$ and 10% of $R_f$. The maximum grade efficiency (Ei) was 51.6% for a 300 ${\mu}m$ particle size at an inflow rate of 600 mL $s^{-1}$ with 23% of $R_f$. The maximum reduced grade efficiency (E'i) was 37.6% for a 300 ${\mu}m$ particle size at an inflow rate of 1,000 mL $s^{-1}$ with 11% of $R_f$. The results indicate that the separation performance of the LPH for suspended solids removal was size selective and that maximum removal occurred at particle sizes ranging from 300 to 500 ${\mu}m$.