Hazardous Material Debris Collection Systems Delivered

TECH TRANS announces the completion and delivery of it’s most sophisticated process vacuum collection system for a major aerospace project delivered to date.

“The collection and safe disposal of potentially explosive and hazardous debris during automated drilling in an aerospace environment is an issue that is currently gaining rapid assimilation within the industry” States J Byron Walker of California-based Tech-Trans, a company that believes it has solved the problem with Pulsed Cleaning, a process now in use by household names such as Ford Motors and Chrysler, amongst others.

Manufacturing efficiencies have advanced the use of automated drilling providing both higher speeds of hole generation as well as achieving more accurate placement of thousands of holes passing through carbon fibre, titanium and aluminum.

While these automated systems provide the accuracy, repeatability, and speed required to achieve efficient production, to ensure fire safety and product cleanliness standards, the drilling process must also take into consideration the generation of debris that must be removed from the hole both during and after the drill operation sequence.

The currently delivered system was designed as a “central” collection point to facilitate the handling of debris generated at multiple locations simultaneously. Several drill stations (5) were automated which meant any of the 5 could be in operation at one time, or all at the same time. There were also a number (3) of manual stations which were “tied – in” to the main system as well. Any of these stations could likewise operate at the same time as the automation was engaged.

Proper flow rates and sizing of the system under the above conditions began with the debris being recovered to determine it’s propensity for explosion. After documented tests of the samples received, fire and explosion data, under the parameters of N.F.P.A. Code 68 were established and vessel sizes and flow rates as defined by the location of the main system relative to the points of collection were calculated and confirmed relative to this critical data. The system incorporates critical temperature sensors in three major locations and the system controls for independent fire suppression in the event of a “fault”. The sizing of the vessel, including fabrication to ASME / ANSI standards and full weld certification, was considered as part of a volumetric analysis of the materials such that air to materials ratios will never archive a critical explosion level of saturation.

Further safety devices were also incorporated to meet the stringent requirements to meet full compliance with any current or future pending safety standards. These included the addition of a “RUPTURE DISK” which becomes the main pressure relief if an explosion were to occur, as well as provides a safety cut-off of the system simultaneous to detection. Further, a “FLAME-QUENCH” system is also in series to capture and contain any flame from generating a secondary deflagration . Usually it is this second event which poses the highest risk to workers and to property.

Finite cleaning, including the collection, transfer, and, control of carbon fiber dust generated as part of the drilling process required special consideration. The safe transfer, filtration and containment of these types of materials is causing some debate and investigation (Scientific American, May, 20, 2008 – Larry Greenemeier)*: in particular as regards the dangers of carbon fibre dust being ingested or inhaled (graphitosis).

“Within a manufacturing environment, we tend to lean to the safer side of any equation in optimizing systems efficiencies and worker health and safety. Thus to ensure proper and safe filtration of the air stream when collecting extremely small carbon fibres, the use of bag or paper-type filters was ruled out by Byron Walker”. Carbon fibre, when broken down during drilling or routing, can take on an elongated and narrow shape, such as an arrow. As such a permanent filter assembly was incorporated which provides ZERO-maintenance, and also offers the benefit of being sintered in construction which eliminates the passing of these finer debris’ into work place.

About: J. Byron Walker

Mr. Walker is the President and owner of Tech-Trans Unlimited Corp, a U.S. Company founded in 1984 and incorporated in 1987. TTUC designs, builds and installs automated and stand-alone vacuum recovery systems including tooling and mechanical components. He is the holder of patent “Pulsed-Cleaning” and several other patents-pending.

In addition, Mr. Walker has considerable experience in factory automation, robotics, and systems integration gained from extensive contracts within the automotive and aerospace sectors. He has been employed as Automotive Operations Director (Unimate /Westinghouse Robotics) National Sales Director (United Technologies) Automotive Centre Director (ABB Robotics) and Northrop Grumman – Calif.)

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