Roller vessels

These may be 2-2.5 1 Winchester, glass bottles (which are cheap and can be reused) or one of the commercially produced plastic roller 

The plastic bottles come in a series of lengths (surface area up to 1750 cm2) and Flow Laboratories market a corrugated roller bottle which has a standard length, yet a surface area of about 1750 cm2. Cells cannot be scraped from this bottle and must be removed by trypsinisation. 

The cost of these plastic roller bottles is high (over 5 each) and they are not generally reusable. It is not, therefore, economical to use them for large scale growth of cells on a regular basis. For such requirements the use of microcarriers should be considered ( 3.4). 

Machines to rotate the bottles are available commercially from a number of companies (e.g. Wheaton, Luckham, Hotpack, Voss Appendix 3) and many home made ones are in use (see Fig. 3.3). At Glasgow University one type of machine made in the Biochemistry Department will roll up to 120 bottles and in the Instituto Zoopro-filattico Sperimentale in Brescia they can roll up to 7000 bottles simultaneously. 

The Wheaton roller apparatus comes in modular form. The base unit holds the drive and will roll 5 bottles. Up to 8 additional decks can be added to allow rotation of up to 45 bottles. Also available is an alarm system which gives warning of rotational failure, and an auxiliary battery system which will enable the apparatus to operate for up to 48 h in the absence of an electricity supply. 

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The patented system (15) has stationary disks mounted inside a pressure vessel (horizontal vessel, vertical disks) which is mounted on rollers and can rotate slowly about its axis. A screw conveyor is mounted in the stationary center of rotation it conveys the cake, which is blown off the leaves when they pass above the screw, to one end of the vessel where it falls into a vertical chute. The cake discharge system involves two linear sHde valves that sHde the cake through compartments which gradually depressurize it and move it out of the vessel without any significant loss of pressure. The system rehes entirely on the cake falling freely from one compartment to another as the valves move across. This may be an unrealistic assumption, particularly with sticky cakes when combined with lots of sliding contact surfaces which are prone to abrasion and jamming, the practicality of the system is questionable. 

The stabihty of the emulsions further permits them to be compounded in simple Hquid-blending vessels by means of agitators, eg, marine-type propellers, paddles, or turbines. The adhesives can be adapted to any type of machine appHcation, ie, from spray guns to rollers to extmder-type devices. Different appHcators are fairly specific in their viscosity requirements, as are the various substrates receiving the adhesive. 

Hum the Bides of the future vessel being prepared by toning on a moistened gypsum slab, a, under a wooden roller, l—Fig, 481, When, from the elegance or complication of form, the admission of the hand into tire mould is impossible, it has boon stated that double... 

Alternative procedures are paddle dyeing for sensitive skins in an open vessel, and immersion dyeing, in which the leather passes through a dye solution and is subsequently squeezed by a roller. Spraying and roller machines have mostly replaced other techniques such as traditional brush dyeing, which colors the surface only. 

Blending of small batches, up to about 4.5 kg (10 lb) is most frequently done in wide-mouth jars, placed on horizontal rollers, tumbling at approximately 15 rpm for about 20 min. Larger, commercial batches, sizes typically 10 to 136 kg (22 to 300 lb) are often prepared in twin-shell blenders (Figure 4.10) by tumbling 15 min at 24 rpm. The blend is screened again, transferred into a storage vessel, and allowed to age for at least 12 hours.8... 

The basic need for a solid support guides all production choices involving industrial processes for adherent cells. A large variety of vessels has been developed for adherent cell cultures. Petri dishes, Roux bottles, T-flasks, and roller bottles are examples of cell culture vessels with a glass or polystyrene surface. The system of choice is dependent on the seal-ability of multiple steps, as well as the cost of equipment and qualified operators. 

Here gaseous exchange, pH control and medium replenishment occur in a second vessel distinct from the cell growth chamber. From this vessel the medium is pumped into the growth chamber which may be a modified microscope slide, a roller bottle or a capillary bed etc. 

Various other procedures have been devised to increase the surface area within a vessel upon which cells may grow. The problem is always to maintain an adequate supply of nutrients including oxygen and to remove waste products, particularly acid. The New Brunswick Scientific Co. (Appendix 3) produces a piece of apparatus which continuously perfuses roller bottles by means of a rotating cap through which the various feed tubes pass. 

The diameter of microcarrier beads is usually about 200/im so the surface area of 1 g of beads is 0.6 m2 which is equivalent to 7 roller bottles, 27 Roux flasks or 315 5-cm Petri dishes (see Table 3.1). With 1 g of beads in 500 ml medium in a suspension flask the surface volume ratio is 12 compared with 4-6 for traditional vessels which means that medium replacement must take place two to three times as often. 

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