Rubber media filters

Instead, membrane filtration may be used to sterilise the nutrient in this experiment. This can be accomplished by drawing the nutrient from a mixing jar and forcing it through an in-line filter (0.2 p,m pore size) either by gravity or with a peristaltic pump. The sterilised medium is fed into an autoclaved nutrient jar with a rubber stopper fitted with a filtered vent and a hooded sampling port. 

The choice of the filter medium is often the most important consideration to ensure efficient operation of a filter. Its function is generally to act as a support for the filter cake, while the initial layers of cake provide the actual filter. The filter medium should be selected primarily on the basis of its ability to retain solids without binding. It should be mechanically strong and corrosion resistant, and should offer as little resistance as possible to the flow of the filtrate. The media are made from widely different materials such as cotton, wool, linen, nylon, jute, silk, glass fiber, porous carbon, metals, rayon and other synthetics, and miscellaneous materials like porous rubber. Cotton fabrics are most commonly used because they are available in a wide variety of weaves, and are cheap. 

A belt filter consists of an endless reinforced rubber belt, with drainage hole along its centre, which supports the filter medium. The belt passes over a stationary suction box, into which the filtrate is sucked. Slurry and wash water are sprayed on to the top of the belt. 

Figure 7.5 Apparatus for testing the microbial retention characteristics of membrane filters. The whole apparatus is sterilized, and initially the flask contains 140 mL of double-strength culture medium. The culture to be tested (100 mL) is passed through the filter with clamp 1 open and clamp 2 closed. The sides of the filter apparatus are washed with two 20 mL portions of sterile broth. Clamp 2 is then opened, the vacuum released, and clamp 1 closed. The filter apparatus is replaced by a sterile rubber stopper and the flask incubated. Absence of turbidity in the flask indicates that the filter has retained the test organism. From Brock [4]. Courtesy of Thomas D. Brock...

Fig. 1. Kubitschek style chemostat. A, Air pump B, hosecock clamps (closed during autoclaving) C, growing culture D, air exit port E, ground glass joints F, syringe filter, G, gang valve H, bottle containing water I, input area K, heating tape M, fresh medium O, siphon P, peristaltic pump R, rubber stopper with holes S, splash shield T, silicone rubber tubing W, waste Y, waste collection tube. Circles in the liquids represent bubbles. Stippling indicates media with cells.

Fig. 4.3. (A) Diagram of the amnion invasion assay. The invasion chamber represents a cylindrical well produced by a Teflon ring (a) to which epithelium-free amnion (b) is fastened with the aid of a viton ring (c), to face the BM side up and stromal side down. A smaller lower chamber is created by a silicone rubber ring support attached to the bottom of a 35-mm tissue culture well (d) with silicone grease, and filled with medium. The (upper) invasion chamber is placed on this support, and medium with or without additives (to be tested for invasion-blocking or stimulating ability) is added to this chamber 1 h prior to the addition of labeled cells to be tested for invasive ability. Medium is then added to the tissue culture well (d) outside these chambers to bring the fiuids inside and outside the Teflon ring to the same level (e) represents a well that includes the complete invasion chamber seeded with cells on the BM. (Reproduced from Yagel et al., 1989.) (B) (a) Human amnion. Epithelium (EP), basement membrane (BM), connective tissue stroma (ST). Haematoxylin-eosin PAS stain, (b) Denuded human amnion membrane. Basement membrane (BM), connective tissue stroma (ST), Milfipore filter (F). Haematoxylin-eosin, PAS stain. (Reproduced from Russo, 1986.)...

Use Decolorizing of oils and other liquids, oil-well drilling muds, insecticide carrier, floor-sweeping compounds, cosmetics, rubber filler, carrier for catalysts, filtering medium. 

Use Rubber filler ceramics, glass, refractories absorbent for crude oil spills manufacture of permanently dry resins and resinous compositions paints, varnishes, and paper (filler) animal and vegetable oils (bleaching agent) odor absorbent filter medium catalyst and catalyst carrier anticaking agent in foods. 

USE Decolorizes for oils and other liquids filtering medium Filler for rubber in agricultural formulations also instead of absorbent charcoal. 

The apparatus is showm in Fig. 26. The electrolysis cell is a tall 250-mi beaker without spout, a so-called electrolytic beaker, and it is closed with a large rubber stopper. The anode chamber is a small porous cup of test-tube form. This must have sufficient porosity to conduct the current but not so much that the anode solution can diffuse out freely. The author tried an alundum Soxhlet thimble and found it unsatisfactory. A piece of the candle used in bacterial filters should be satisfactory. The author has used a sintered glass Gooch crucible, medium... 

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