Mixer apparatus configured to mix the contents of a vessel without the formation of a vortex are provided. The mixer apparatus can include a rotational mechanism; a gearbox attached to the rotational mechanism; a first shaft attached to the gearbox; a second shaft attached to the gearbox; a first rotor configured to be rotated by the first shaft; and a second rotor configured to be rotated by the second shaft. The first shaft can be coaxial with the second shaft, and the gearbox can be configured to rotate the first shaft and the second shaft in opposite directions. The first rotor and the second rotor are configured to be rotated in opposite directions.

A method for stirring resin pellets, which includes stirring adhesive resin pellets in a liquid in a stirring tank equipped with a stirring impeller, under the condition satisfying the following relational expression (I):

[00001]$\begin{array}{cc}\frac{\rho .Math..Math.{\left({\mathrm{Np}}^{1/3}.Math.\mathrm{nD}\right)}^2}{\Delta .Math..Math.\mathrm{pgdp}}\geqq 10& \left(I\right)\end{array}$

wherein ρ is the density of the liquid (kg/m.sup.3), Np is the power number of the stirring impeller, n is the rotational speed (1/s), D is the diameter of the stirring impeller (m), Δρ is the difference in density between the resin pellets and the liquid (kg/m.sup.3), g is the gravitational acceleration (m/s.sup.2), and dp is the particle diameter of the resin pellets (m).

A bioprocess vessel includes a flexible bag or substantially rigid container that defines an interior volume and having a bottom surface, the bottom surface being open or containing an aperture therein for the passage of fluid. A pump is secured to the bottom surface of the flexible bag or substantially rigid container. In some embodiments is secured directly to the flexible bag or substantially rigid container. In other embodiments, the pump is secured indirectly the flexible bag or substantially rigid container using, for example, a port that extends through the aperture on the bottom surface. The port or flanged surface may also be integrated into the pump, which is secured to the vessel. An optional mixing adaptor may be provided inside the interior volume of the flexible bag or substantially rigid container and at least partially covers the inlet that leads to the pump.

A bioprocess vessel includes a flexible bag or substantially rigid container that defines an interior volume and having a bottom surface, the bottom surface being open or containing an aperture therein for the passage of fluid. A pump is secured to the bottom surface of the flexible bag or substantially rigid container. In some embodiments is secured directly to the flexible bag or substantially rigid container. In other embodiments, the pump is secured indirectly the flexible bag or substantially rigid container using, for example, a port that extends through the aperture on the bottom surface. The port or flanged surface may also be integrated into the pump, which is secured to the vessel. An optional mixing adaptor may be provided inside the interior volume of the flexible bag or substantially rigid container and at least partially covers the inlet that leads to the pump.

An apparatus and method for mixing a liquid having particulate includes a vessel for containing me liquid an axial impeller rotating about a substantially vertical axis. The impeller is adapted for submerging below the liquid surface by a distance approximately one-quarter to one-half of the height of the liquid. The impeller is oriented upwardly to produce (a) an inner, upward flow region located along the vertical axis of the vessel, (b) a transition flow region above the impeller in which liquid moves radially outwardly toward the vessel sidewall, and (c) an outer, downward flow region located along the sidewall. The impeller spins at a variable speed, such that the flow is capable of entraining solid particles having a settling velocity of up to approximately 1 foot per minute in the liquid, and the speed of the impeller is chosen to enable particles having a desired settling velocity to settle to the vessel bottom.

A hydrofoil impeller wherein the tip edge is straight and has a right angle with a radius extending from the central axis to the tip edge. In the central hub and in each of the blades the number of holes in each group of first and second holes is at least five. The pattern in which the holes are arranged in each of the respective groups of holes is elliptical having a center and a major axis which is substantially parallel to the radius and placed at a distance therefrom. The leading edge is, in the direction to rotation, behind an imaginary radial line intersecting the central axis of the shaft and the center of the ellipse, said leading edge being at an angle of 58°±2° in relation to the radial line. The area of the blade is divided into four planar portions by three straight bends.

A fluid holding structure fluid circulating system includes a fluid movement assembly with a propeller including a housing having a perimeter wall and a plurality of blades attached to an outer surface of the perimeter wall. A motor is mechanically coupled to the propeller and is positioned above the propeller. A buoy has buoyancy in fluid great enough to raise the fluid movement assembly adjacent to a surface of a fluid holding structure when the motor is turned off. The motor is mounted within the buoy and the propeller urges fluid upwardly toward the buoy when the motor is turned on to rotate the propeller. The propeller is completely exposed around its lateral periphery. A positioning cable is attached to the fluid movement assembly to facilitate movement thereof within the fluid holding structure.

Methods and systems for chromatography are disclosed that employ a flexible container configured to fit within a support structure and adapted to receive a filtration or absorptive medium. The flexible container can include at least one inlet, at least one outlet, and a separation barrier peripherally sealed within the container to separate the container into a resin containing portion and a drainage portion. The barrier can be configured to exclude the resin material from the drainage portion while allowing fluids to pass therethrough. The disposable chromatography system can further include one or more agitators disposed within the flexible container and adjustably configured to be raised or lowered in the flexible container. When the agitator is in the raised position, the resin packing material can operate in a settled, packed-bed configuration. Alternatively, the agitator in the lowered position permits the chromatography resin packing material to operate in a mixed, slurry configuration.

Attrition mills and propeller shaft assemblies therefor are described having features for enhanced installation and maintenance. Some embodiments include propellers having enhanced material processing characteristics.

The invention relates to a process for preparing a solid support for a procatalyst suitable for preparing a catalyst composition for olefin polymerization, said process for preparing said solid support comprising reacting a compound R.sup.4.sub.zMgX.sup.4.sub.2-z with a silane compound Si(OR.sup.5).sub.4-n(R.sup.6).sub.n in a solvent and mixing the resulting mixture with a mixing device and at a certain mixing speed in order to give a solid support Mg(OR.sup.1).sub.xX.sup.1.sub.2-x said solid support obtained having an average particle size of at most 17 μm, preferably at most 16 or 14 μm, more preferably at most 12 μm. The invention further relates to a solid support, a process for preparing a procatalyst and said procatalyst as well as polyolefins obtained using said procatalyst.