Types of whole welded filters

With participation of this site's author there were developed welded filters, based on foil membranes usage, construtions and production technologies of such filters for extra pure hydrogen manufacturing. Main types of the developed whole welded filters are showed below : flanged - one- and double-sided - (a); disc (b); bellow (c); bag (d) and flag (e).

As could be seen, the smalest and simplest filters belong to the so-called flanged and disc types; the biggest filters - according to their productivity - are bag and flag types, and the middle position posseses the bellow type of filters. Some such filters picture you can also find in our www.pogrebis-temp.com/unique.html. As a filter material for membranes were used foils 0,02-0,1 mm thick of palladium based alloys, containing 5-30 % of silver plus other chemical elements. Because it was very difficult to assemble the edges of such foil without essential gaps and displacement it was developed the method of microplasma welding in such hardly conditions (please, see our unique innovations). This method has been realized in the modular-inverter AMC-1welder (please see also our www.pogrebis-temp.com/technologies.html). Depending on the configuration, sizes and conditions of operation, each filter from foil provides an output of ten up to many hundreds of liters of extra pure hydrogen per hour. As compared with filters made from capillary tubes by brazing or by powder pressing, new filters, made from Pd-based foils and welded by microplasma, are cheapper, allow higher temperature (about 630 degrees of Celsium scale and higher) and more severe corrosion conditions of work, giving, due to this fact fuller and more effective hydrogen extraction. Such filters may be also used in scientific research, for inert gases cleaning, for heavy water production, etc. In cases when filters from capillary tubes are preferable (for example, if the gas mixture, including hydrogen, has to be operated under big pressures - 200-300 atmospheres) the AMC-1 SET may be also useful because it can give excellent results in order to close (to weld) the free end of each capillary. We made unique microstructure research of regular and improved edge welds of the above mentioned foils and of dissimilar welds while a foil had to be welded to the thicker constructional material (please, see our microstructure photos on www.pogrebis-temp.com/unique.html, www.pogrebis-temp.com/technologies.html and www.pogrebis-temp.com/materials.html).

It has to be noted that during transportation (in tubes and pipe systems) the obtained extra pure hydrogen essentially loses its cleanliness and activity. So, when it reaches a so-called "reacting" zone (for instance, where germanium monocrystal is growing) this hydrogen effectivity falls perceptibly. At the same time it has been exactly established that when using extra pure hydrogen immediately - after its producing - this hydrogen, being in so-called "atomic" condition, acts with tremendous activity as opposed to the so-called "molecular" condition. For example, the "atomic" extra pure hydrogen can produce very pure metals directly from their oxides. And because of the possibility of working under heightened temperatures, small sizes and good flexibility - to productivity - some types of the mentioned above welded filters may be placed and used directly in the zone of super hydrogen consumption (growing of Ge or Si monocrystals, metal oxides or ores restoration).

Giving hydrogen with cleanness no less than 99,99999%, small whole welded extra pure hydrogen filters may be used in every university for various scientific research, and of such universities there are hundreds in the world.

Alike to such filters there are developed catalytic reactors with a hydrogen-permeable membrane wall which were proposed for the first time in the Russian A.V. Topchiev Institute of Petrochemical Syntheses and are based on two processes that take place in one reactor which makes quick preparation of cyclohexanone from phenol. For these purposes the metal membrane is preferable, consisting Pd-Ru alloys, while for hydrogen purification are often used complex alloys, including V-1, Pd-Ag and Pd-In-Re alloys. In any case the membrane materials have to be as thin as possible and be connected with full seams hermetization. Many various institutes and organizations work now in this field: the European Membrane Society; Palladium Development Corporation ; the Lehigh University (where an original microreactor production by catalytic methanol reforming was developed); the University of Cincinnaty (it was proposed the Fabrication of a Thin Palladium Membrane Supported in Porous Ceramic Substrate by Chemical Vapour Deposition); China Chemical Engineering (the Dehydrogenization and Hydrogen Occuring in Tubular Palladium Membrane Reactor); the 5-th International Conference of Microreaction Technology (there was reported about Palladium Based Micro- Membrane for Water Gas Reaction and Hydrogen Separation), etc. ,(you can visit, for example www.resourceinvestor.com/pebble.asp?relid=24298).

Microplasma welding is very effective for producing of other filters as well as for fuel elements made from thin porous nickel and other materials (it has been shown by Dr.Lev Mironov and his followers). Excellent results are reached in thin metallic meshes welding. For these purposes our cheap, safe and simple sets may be also used .

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