TPT September 2021

T E CHNOLOG Y

TIG welding in ultra-high purity tube industry WHENEVER high-quality joints are required, gas tungsten arc welding or tungsten inert gas welding offers a solution. A wide range of products have to be manufactured under white room or clean room conditions. These products may be susceptible to microbes, as it is the case with pharmaceutical ingredients, to contaminations, as seen in the field of micro-electronics, and to foreign objects, which have to be kept out of optical devices and precision mechanics. A wide range of tube products have to be manufactured in clean room conditions

In many cases the components for the equipment, which is intended to be operated inside of clean rooms, have to be produced and assembled under controlled atmosphere as well. Tube networks are frequently used to supply clean room installations with ultra-pure gases and liquids, which are used for inertisation, etching, rinsing, diluting and injection purposes. In order to minimise the effort on site, as many as possible of the connections for the tube network installation of a clean room supply are pre-fabricated. In the factory; standard pieces like micro-fittings, tees, elbows and valves are welded together with matching tube segments. Here, the use of orbital TIG welding can provide significant advantages. Complete weld cycles are carried out automatically and lead to consistent high-quality results. White or clean rooms are specifically designed for the requirements of a particular sector of activity. Composition, temperature and humidity of the controlled atmosphere are regulated

by precise specifications, but the most important limits concern the size and number of airborne particles. Depending on the highest permitted particle concentration the standards ISO 14644-1 and FED STD 209E divide clean rooms in different classes: Iso Klasse 1 and FED class 1 stand for the lowest particle concentration, whereas Iso Klasse 9 and FED class 100,000 are equivalent to unfiltered room air. To keep the contamination inside a clean room as low as possible, any generation or emission of particles has to be avoided. Sending out an average stream of 100,000 particles per minute with a size of less than 50µm the human body is considered as one of the most important particle sources in a clean environment, especially in case of fast movements. Thus, workers or visitors in a clean room have to wear specific cloths: the head and hair are covered by a cap, the face including eyes, nose and mouth is completely enclosed by a protective mask with goggles, the hands are

gloved, galoshes fit over standard footwear and the rest of the body is wrapped in an appropriate lab coat or working suit, standard footwear and the rest of the body is wrapped in an appropriate lab coat or working suit. Manufacturing processes can also be the origin of significant particle emissions. Each electric arc that is struck during a TIG welding procedure is accompanied by clouds of vaporising metal and streams of welding and backing gas. Additionally, the released heat provokes turbulences between inert gas and surrounding air and entrains undesired pollutants. However, the adverse side effects of an open arc can be avoided. Closed orbital welding heads were initially invented as fast and efficient tool for the numerous butt weld connections of airplane hydraulics. Ease of use, productivity and outstanding weld quality were the targets of the development.

Polysoude www.polysoude.com

Traceability in highly abrasive environments INFOSIGHT Corporation is bringing identification and traceability solutions to highly abrasive environments. The company has introduced Gorillabel TM to identify components used in highly abrasive environments, such as oil drilling and fracking. in temperatures over 300°C (570°F) and extended slurry abrasion.

Other potential applications include fracking components, mining compo- nents, and bulldozer and backhoe parts. Data vital to the operation of each component, such as maintenance records and length of service, becomes immediately available to the operator with a simple smart phone scan. This is useful for planning maintenance on equipment and reducing risks to both production and safety.

The identification label, which is pre- marked by InfoSight, is a transparent Gorilla ® Glass disk. InfoSight recom- mends countersinking the label into a shallow machined pocket so the surface of the component remains level. After severe abrasion, wiping the label with a liquid which matches the glass index of refraction restores its

clarity. The label will survive anything the component must survive, including: boilouts – leaning at or above boiling temperatures (100°C/212°F) and high pH (12 or above), long term immersion

InfoSight www.infosight.com

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SEPTEMBER 2021