Environmental seal

Entzundungstemperatur = deflagration point 75 environmental seal 120 environmental testing > rocket test stand 275... 

We developed a submersible electrode assembly, connected to a 50 ft (24 m) long shielded cable (via environmentally-sealed rubber connectors), for the real-time in-situ monitoring of the TNT explosive in natural water [10]. Such sensor assembly consists of the carbon-fibre, silver, and platinum working, reference, and counter electrodes, respectively, and operates in the rapid square-wave voltammetric mode. Such a remote/submersible probe circumvents the need for solution pumping and offer greater simplification and miniaturization. The facile reduction of the nitro moiety allowed convenient and rapid square-wave voltammetric measurements of ppm levels of TNT. Lower (ppb) concentrations have been detected using a... 

Two products, PR-711 and PR-719, are manufactured by Products Research Chemical Corp. PR-711 was used for environmental sealing of structural faying surfaces of the first two flights of the space shuttle orbital airframe. PR-719 is designed to seal integral fuel tanks of aircraft. The sealant has to be a non-curing type so that the channel can be resealed without disassembling the structure. 

Not all components are compatible with the water-wash process. Circuit board mounted switches are notable in this regard. Even some switches sold as environmentally sealed or water-wash-compatible have been found to leak during the high-pressure wash spray or submersion steps of aqueous cleaning. This can result in failure of the switch to work properly (the water causes an electrical short within the switch) or, if there is enough ionic content in the wash water or in the switch itself, switch contact corrosion may occur in the long term. 

Demands for improved efficiency in aircraft gas turbines led to the use of a family of age hardenable, controlled expansion superaHoys for engine seals and casings. INCOLOY aHoys 903 [61107-16-2] (UNS N19903), 907 [107652-23-3] (UNS N19907), and 909 evolved from a continuing effort to improve the environmental resistance of this Cr-free, Fe—Ni—Co based system. 

Residue Disposal. The major environmental problem in the Bayer process is disposal of bauxite residue which is effected by marine disposal, lagooning, use of underdrain lakes, or semidry disposal. Marine disposal in oceans or rivers, diluting the alkaline residue by large quantities of water, is environmentally unacceptable. Lagooning behind retaining dikes built around clay-sealed ground is commonly used, but there have been isolated leaks into aquifers. This has motivated installation of underdrains between the residue and clay-sealed, plastic-lined, lake bottom. This design removes the hydraulic head from the lake bottom and improves consoHdation of the residue. 

Environmental Standardfor Re-Refined Engine Oil, Standard GS-3, Green Seal, Inc., Washington, D.C., 1992. 

The aimual production value of small, sealed nickel—cadmium cells is over 1.2 biUion. However, environmental considerations relating to cadmium are necessitating changes in the fabrication techniques, as well as recovery of failed cells. Battery system designers are switching to nickel —metal hydride (MH) cells for some appHcations, typically in "AA"-si2e cells, to increase capacity in the same volume and avoid the use of cadmium. 

The environmental laws favor mechanical seals over packings. The need to conserve energy favors mechanical seals. The needs to reduce labor costs and consumption of natural resources favor the mechanical seal over packings. 

The storeroom techs must protect the mechanical seals handling them with extreme care. The engineer or technician must specify and select the seal components correctly. The mechanical maintenance technician must protect the seal at the moment of installation. Once the seal is installed into the pump, the seal requires the correct environmental controls to assure optimum life. At this point the work of the maintenattce technician ends. 

For most applications, the balanced, o-ring cartridge seal will adequately handle every pump, liquid, and condition in a modern industrial process plant. There are, however, some industrial pumping applications that will present problems to even the best of mechanical seals. Should one of these applications cause the seal to give less than desirable performance, the next step to take in extending the service life of the seal (and ultimately the pump) is to install some type of environmental control to protect and isolate the seal components from the fluid. Let s consider some difficult sealing applications. 

The following pictures show different arrangements of Environmental Controls. These Controls expand the operational range of the mechanical seal, improving the pump service life. 

You ve just seen six different concepts to control the environment inside the seal chamber and mechanical seal. Some methods are economical. Others are costly. Some have secondary side effects to contend with. Now let s consider the 14 difficult sealing situations and apply the environmental controls to extend the running time of the seal and pump. 

Once an adequate definition of the product is made, the design of the seal environment can be selected. There are four general parameters that an environmental system may regulate or change ... 

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