[Laser] Contentof Laser Digest, Vol 77, Issue 1, LASER Cutter

Tue Mar 1 13:54:39 EST 2011

I very much doubt an Oxygen lance is acceptable in a rescue situation.

FWIW,

-John

=================

>
>
> It must be a very big batt!
>
> 300 ft lenght x 1/2" thickness x 1/20" cut = approx. 90 inch ^3 volumen
> to melt, Fe -> 131 gr/inch^3 -> 11.8 kg Fe.
>
> Heat of fusion (Fe) 14 kWs/mol, specific weight of Fe ~19 g/mol. 11,8 kg
> Fe -> 620 mol, needed Power 620 mol x 14 kWs/mol = 8700 kWs. In 6 min =
> 360 sec, 8700 kWsec /360sec = 24 kWatt optical Power for 6 Minutes. The
> electrical power for the laser must many times the optical power.
>
> If the cut is down of 1/200" (a very sharp focus) the needed Power
> decreases by 1/10. P -> 2.5 kW optical Power. Many kWatt's electrical
> power also.
>
> The efficiency of lasers differs from 3 to 40 %. For cutting is a stream
> of oxygen helpfull the iron burns in O2-gas and produces additional heat
> for melting.
>
> This system should be possible. Not more then 5 kW for 6 min are needed.
>
> Dieter - dl7udp -
>
>
>
> -----Ursprüngliche Nachricht-----
> Von: laser-bounces at mailman.qth.net
> [mailto:laser-bounces at mailman.qth.net] Im Auftrag von
> laser-request at mailman.qth.net
> Gesendet: Dienstag, 1. März 2011 18:01
> An: laser at mailman.qth.net
> Betreff: Laser Digest, Vol 77, Issue 1
>
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> Today's Topics:
>
>    1. Battery-powered LASER cutter could save car accident victims
>       (bernieS)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 01 Mar 2011 11:40:45 -0500
> From: bernieS <bernies at netaxs.com>
> Subject: [Laser] Battery-powered LASER cutter could save car accident
> 	victims
> To: laser at mailman.qth.net
> Message-ID: <20110301164054.A73BC88011 at mailman.qth.net>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> Does anyone here besides me think it's a bogus claim that this thing
> can "cut 300 feet of half-inch-thick steel in six minutes on a single
> (50lb) battery charge"?
>
> -Ed
>
>
> http://www.emergencymgmt.com/health/Beam-Life-DeviceCar-Accident-022511.
> html
>
> Beam of Life Device Could Save Car Accident Victims
> By: Corey McKenna on February 25, 2011
>
> Two students at Ball State University in Muncie, Ind., are working on
> commercializing a battery-operated laser cutter that could help first
> responders shave minutes off the time it takes to free someone
> trapped in a crashed vehicle. The students, Adam Odgaard and John
> Benjamin, say the device is quieter and generates fewer sparks than
> hydraulic cutters currently used by rescue workers.
>
> The tool, dubbed the Beam of Life Device (BOLD), can cut 300 feet of
> half-inch-thick steel in six minutes on a single battery charge.
> Odgaard said he and Benjamin found that an average extrication takes
> nine to 15 minutes. Odgaard said the BOLD could be at least three
> minutes faster than that. A proposed backpack design could help
> rescuers get into tighter spaces than hydraulic tools.
>
> The current prototype, a desktop model, was developed by Tim Bradley,
> an engineer at the Naval Surface Warfare Center in Crane, Ind. The
> next step is for Odgaard and Benjamin to secure funding to develop a
> smaller prototype in which the power supply fits in a 50-pound
> backpack connected to a wand that a firefighter could operate single
> handedly. The target weight for the device is comparable to the
> weight of similar tools on the market, such as the Hurst Jaws of Life
> line of tools, to which the BOLD is being positioned as an alternative.
>
> "You have to be able to get the shears in there, and then when the
> shears are going it will work against you and tire out most of the
> rescue responders trying to cut through steel," Benjamin said. With
> the BOLD, "you don't have to create an entry for your cutters to be
> placed inside the vehicle."
>
> The BOLD also does away with carbon dioxide emissions so rescue
> workers won't have exhaust from the device blowing back at them.
>
> Odgaard and Benjamin, who both study entrepreneurship, expect
> development of a smaller prototype to take about six months. That
> will be followed by a year of testing and evaluation with fire
> departments. The BOLD could be available for purchase by the end of
> 2012.
>
> In 2009, more than 8,600 people were involved in motor vehicle
> crashes that required extrication, according to the National Highway
> Traffic Safety Administration. That number has been steadily rising,
> according to Frank Pintar, a professor in the Department of
> Neurosurgery at the Medical College of Wisconsin. Pintar is part of a
> team that's studying how to improve extrication methods.
>
> There have been instances, Pintar said, where firefighters have
> endangered themselves or each other while attempting extrications. He
> sees a place in the field for a device like the BOLD if it can reduce
> the likelihood of those injuries.
>
> "I don't see this taking the place of the Jaws of Life," he said. "It
> sounds like it's obviously a quieter device, and it might work just
> as well as a Sawzall without the dust flying all over the place and
> that kind of thing."
>
> One advantage of hydraulic tools is that they support portions of a
> vehicle being cut. "In extrication you can't just cut metal," he
> said, "because sometimes a crumpled [piece of] metal that you cut
> will collapse the rest of the car and you'll actually endanger the
> occupant or other firefighters by doing that. So a hydraulic device
> actually adds stability to a crumpled car as opposed to just cutting
> things away."
>
> Hydraulic cutters and spreaders are useful, Pintar said, when an
> occupant's limb is trapped in some kind of sheet metal. Where the
> BOLD would be useful is when an occupant is trapped in a car without
> being entangled by metal. "Let's say you would cut all the A-pillars
> of the car and just take the roof off, and then extricate the
> occupant from the top of the roof," he said. "Then this device might
> come in handy, but essentially that's what a Sawzall will do as well."
>
> Odgaard and Benjamin are not the only ones attempting to market a
> battery-powered rescue tool. Both Hurst and Milwaukee Electric Tool
> Corp., maker of the Sawzall reciprocating saw, market battery-powered
> tools.
>
>
>
>
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