Gore Tex

Highly porous fabric stmetures, eg, Gore-Tex, that can be used as membranes have been developed by exploiting the unique fibrillation capabiHty of dispersion-polymerized PTFE (113). 

Polytetrafiuoroethylene suture is composed of expanded polytetrafiuoroethylene (ePTEE), resulting in a porous microstmcture having longitudinally oriented nodes and fibrils. The suture is sold by W. L. Gore Associates, Inc. under the trade name Gore-Tex Suture. 

Media made from woven or nonwoven fabrics coated with a polymeric film, such as Primapor, made by SCAPA Filtration, and Gore-Tex, made by W. L. Gore and Associates, combine the high retentivity charac teristics of a membrane with the strength and durability of a thick filter cloth. These media are used on both continuous and batch filters where excellent filtrate clarity is required. 

Pollutants that require an unusually high level of control or that require the fabric filter bags or the unit itself to be constructed of special materials, such as Gore-Tex or stainless steel, will increase the costs of the system. The additional costs for controlling more complex waste streams are not reflected in the estimates given below. For these types of systems, the capital cost could increase by as much as 75 % and the operational and maintenance (O M cost could increase by as much as 20%. 

Stable highly conductive films of PPy-Nafion-impregnated Gore-tex and PPy-Nafion have also been reported. Polymer blends can also be produced by... 

Back-pulse Filtration using GORE-TEX Membrane Filter Cloths... 

The soluble ions of iron and aluminium are usually reduced to a minimum by adjusting the electrolyte pH. For the removal of solid iron hydroxide and aluminium hydroxide Bayer decided to use a new pre-coat-free brine purification technology -back-pulse filtration using GORE-TEX membrane filter cloths. 

Since the installation of the retrofit, the brine quality has been monitored using different types of analysis (MS, ICP, EDX, etc.). The filtration efficiency of the GORE-TEX membranes has always met the Bayer specifications, which are significantly less than 100 ppb iron and aluminium. The filter membranes were put into operation in August 1998 and continue in service at this time. 

Fig. 22.2 Sealing arrangement of the GORE-TEX membrane filter cloths on the support element.

Filling the vessel is an obvious necessity, but because of the fine pore structure of the GORE-TEX membrane (described below), air trapped in the vessel does not pass... 

The filtrate that is back-pulsed from the dome first expands the filter socks thereby cracking the cake. The movement of the socks and the subsequent liquid flow through them serves to dislodge the filter cake solids from the GORE-TEX membrane surface. Because of the expanded PTFE material of the membrane, the cake releases from... 

The final principles of back-pulse filter technology are the nature and properties of the GORE-TEX membrane. The membrane is composed of expanded polytetra-fluoroethylene, or e-PTFE. The membrane traces its roots to the invention of e-PTFE by Robert W. Gore in 1969. Since that time, e-PTFE has found application in many areas including medical devices, electronics, fabrics and fuel cells to name a few. In the filtration area, e-PTFE is used in the form of a membrane to capture and remove particles from both gaseous and liquid streams. 

The success of this and the other operations derives from the correct application of back-pulse filtration principles, in particular the back-pulse step itself in which the filter cloths are cleaned and made ready for further filtration. The properties of the GORE-TEX membrane, composed of expanded polytetrafluoroethylene, give rise to the desirable results of these brine filtrations, in particular ... 

Another potential material for cell construction purposes is nickel. For instance, Eka Chemicals has employed nickel cartridges with standard GORE-TEX membranes to remove graphite particles directly from a caustic decomposer. The result was promising. Not only was the graphite removed but the quantities of mercury were reduced to levels of <10 pg. Aside from the cleaner caustic, the volume of sludge was drastically reduced since no pre-coat was required in this procedure. 

Q CE0 Gore-tex is a popular fabric that provides protection from rain while allowing perspiration to escape. What polymer coating is used to make Gore-tex fabric What special properties does this polymer have What else is this polymer used for Research the answers to these questions. 

Liu, C. and Martin, C. R. 1990. Ion transporting membranes II. Ion transport mechanism in Nafion-rmpregnated Gore-Tex membranes. Journal of the Electrochemical Society 137 510-515. 

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