Marine Impeller Research Articles

Particle-Impeller Impact for a Six Bladed 45.DEG. Pitched Turbine in an Agitated Vessel.

The rate and position of particle-impeller impact for a six-bladed 45°-pitched turbine in the vessels of different scales were measured by the crayon method developed by the authors previously. The impact rate of the pitched turbine pumping upward is higher than that of the pitched turbine pumping downward, but both of them are about 1/6 and 1/17 time, respectively, that of a Rushton turbine. A mathematical model was developed to explain the high dependency of impact rate on impeller speed and impeller diameter. The impact mostly occurs in the outer and upper corners of the blades for the pitched turbine pumping downward, which is consistent with that of the abrasion point of blades of marine impellers used in the chemical industry.

A quantitative analysis of shear effects on cell suspension and cell culture of perilla frutescens in bioreactors

The short-time effects of shear on suspended cells of Perilla frutescens were quantitatively analyzed by exposing the cells to a well-defined flow field in a rotating drum reactor. It was found that both shear rate and shearing time significantly affected cell viability. The quantitative effects of shear on cell growth and the production of anthocyanin, a secondary metabolite, by the cell cultures were further investigated in a series of batch cultivations using a 5-L plant cell bioreactor with a marine impeller. The results indicated that there was an optimum range of shear rate; i.e., an average shear rate of 20 to 30 s(-1) or an impeller tip speed of 5 to 8 dm/s, which maximized all the values of the following parameters: the specific growth rate, the maximum cell concentration, the (specific) production and productivity of anthocyanin, and the cell and anthocyanin yields.

Problems of optimisation of plant cell culture processes

The adoption of plant cell cultures as an industrial process depends greatly on the economics of such a process. The multicycle or draw-fill culture technique is one method for improving the productivity and, hence, cost of a process. Mathematical models have been devised for the functional relationships between the nominal costs of biomass and secondary metabolites and the plant cell growth characteristics in a multicycle growth system. The models were used to evaluate the data obtained with cultures of Dioscorea deltoidea (which produces diosgenin) and Panax ginseng, grown in various types of bioreactors. The multicycle system gave an increase of 1.5–2 in biomass productivity compared with batch culture, but was probably only commercially viable if the cost of the process in the bioreactor was at least 30 times that of the medium and if an inoculum of about 30% of the culture of the previous cycle was left in the bioreactor. In the multicycle system incompletely utilised nutrient or metabolite accumulation can only reach 1.43 times or less that of the initial values. With the P. ginseng culture, about 75% of the calculated maximum cell packing density per fresh weight (≈ 530 g l −1) in this regime was achieved. The possibility of growth in the standard bioreactor of a shear sensitive type culture was shown with a marine impeller speed up to 330 cm s −1.

Preparation of hemolysate‐filled hexamethylene sebacamide microcapsules with controlled diameter

AbstractHemolysate‐filled hexamethylene sebacamide microcapsules (nylon‐6, 10 membranes) were prepared by interfacial polymerization. Sheet lattice, frame lattice, turbine and marine impellers were tested to control the microcapsule mean diameter and size distribution parameters. Mean diameters ranging from 40 to 200 μm were obtained depending on the impeller type, rotational speed and emulsifier concentration. The size dispersion of microcapsule preparations was best controlled with a frame lattice impeller, achieving standard deviation values less than 40% of the mean diameter. The wire diameter and mesh dimensions of the impeller lattice had little effect on the distribution parameters.

Large‐scale production of monoclonal antibodies in suspension culture

Monoclonal antibodies are being manufactured for clinical trials in suspension culture at the 1300-L scale. Suspension culture offers some advantages relative to high-density mammalian cell culture methods; in particular, the ability to closely monitor the behavior of cells in a homogeneous environment. Computer control and on-line mass spectrography of exit gases provide instantaneous information about the culture metabolic activity. Air sparging and agitation by marine impeller provide aeration sufficient to maintain a constant dissolved oxygen tension at cell concentrations up to 5.0 x 10(6) cells/mL without causing apparent cell damage.

Process control during the suspension culture of a human melanoma cell line in a mechanically stirred loop bioreactor

A human melanoma cell line was cultivated for more than 5 months in a serum-free medium without macromolecular growth factors. A mechanically stirred loop bioreactor was used for the culture of the melanoma cells. The tip speed of the marine impellers was 1.5 m s −1. This cell line was able to endure tip speeds of up to 3.5 m s −1 for a few hours without significant cell damage. By using process control it was possible to obtain growth rates and cell numbers close to those found in medium with serum. The pO 2 was controlled at 125 mbar and the pH at 7.15. The signal of an on-line fluorometer, although not caused by the cells, correlates with cell number. The partial pressure of CO 2 in the culture medium and the redox potential of the medium were monitored by on-line sensors.

COPPER ALLOY No. 858

Abstract Copper Alloy No. 858 is a copper-zinc-tin-lead (yellow brass) alloy for die castings. It is a low-cost, general-purpose alloy with good machinability and soldering characteristics. Its many uses include general and marine hardware, pump, impellers, plumbing parts and gears. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-354. Producer or source: Copper alloy producers.

NI-BRAL

Abstract Ni-Bral nickel-aluminum bronze is a material having high strength and good corrosion resistance. It is recommended for marine propellers, impellers, valves, gears, and shafting. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: Cu-124. Producer or source: American Manganese Bronze Company.