How about a small gearmotor that turns a screw with a puncturing pin at the end? That should be reasonably cheap and easy to fabricate, with a few machine tools (lathe, drill press, mill etc).
iFor hobby I'm working on a project that also involves creating a circuit for activating CO2 cartridge. By activating I mean puncture of cartridge and fill some stuff with CO2. My first approach was using valves, but because my circuit needs to be very small and run on butteries I was forced to use "mini" valves that run on 5V. After some online search all suitable valves I found can only work with pressure with up to 10 BAR, which (I think) will not work with CO2 cartridges.
Is there any other method to "electronically" puncture the cartridge using only elements that run on butteries?
Thank you.
Regards, Igor
Quite correct, since no 5V battery exists.
-- Good day!
________________________________________ Christopher R. Carlen Principal Laser&Electronics Technologist Sandia National Laboratories CA USA snipped-for-privacy@BOGUSsandia.gov NOTE, delete texts: "RemoveThis" and "BOGUS" from email address to reply.
I was also thinking about this method, but I'm not very excited about it.
Can someone think of some other method to electrically puncture CO2 cartridge?
Thank you
Regards, Igor
-- But a lot of nasty molten seal metal flying around.
An NiMH 4-cell battery is close enough, no?
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
A firing pin - the energy to puncture the cartridge is stored in a spring and released by a low-powered trigger mechanism.
CO2 cartridges have about 45 to 50 bar of pressure within, depending on temperature.
Two ways:
1: small DC motor with a centrifugally-actuated snap hammer, like in an impact wrench. Motor winds up in speed until the hammer pops loose, hitting a firing pin. This might be a spring-return hammer with a spring-loaded ball detent that releases the hammer at given speed.2: Capacitive discharge (SCR or MOSFET) into a solenoid. The small battery trickle-charges the cap over time, the cap dumps a pulse of heavy current (10s of amps) into the solenoid at firing time. You might need a voltage boost circuit (flyback) to charge a higher-voltage cap so as to use a solenoid of practical coil resistance.
This might also make good use of momentum -- the solenoid plunger is accelerated over a distance before striking a firing pin that need only move a few thousanths to puncture the sparklet. FT = MV
On Tue, 8 Nov 2005 10:24:59 +0100, "Igor Hudolin" wroth:
The seal will melt at a lower temperature than the cylinder. Wind some nichrome wire around the cylinder and power it with a battery. No moving parts or tricky mechanisms.
Jim
"Frithiof Andreas Jensen" wrote in news:dkq19f$8g0$ snipped-for-privacy@news.al.sw.ericsson.se:
Or driven by an electric-fired primer.
-- Jim Yanik jyanik at kua.net
or a 22 caliber blank cartridge
Do you mean puncture the thin metal seal, or the cartridge body(!)?
And how much power have you got to play with?
Perhaps you could have a small motor driving a cogged wheel attached to a threaded rod with a sharpened end. The motor turns, and the rod screws into the seal. Or have the rod push the cartridge onto a sharp point.
The circumference of the wheel divided by the pitch of the thread gives the mechanical advantage.
K.
doubtfully you can do it with a small 5v battery.
i
On a military sonarbuoy project I worked on we did this by having a spring loaded spike that was held in place by a string which was rapped around a resistor body. Pass current through the resistor and it heats up burns the string and releases the spring loaded spike which punchures the can.
This mechanism was manufactured in the tens of thousands and proved
100% reliable. It even survived the harsh conditions of being slammed into the ocesn from a helicopter or plane.Dave :)
Just a random thought, mebbe a solenoid to drive the cylinder home into the nozzle. The cylinders are steel from memory, perhaps the solenoid could be made large enough to encompass the cylinder ?
-- Regards ......... Rheilly Phoull
I had an interesting expirience wih a fire system in a tank. They usd a cartridge to fire open the valve,ignition was by current pulse. It produced a hell of a mess,all yellow/brown powder all over the place.
Burry.
Sjouke Burry wrote in news:43711df3$0$485$ snipped-for-privacy@nova.planet.nl:
You can now buy "clean" electric primers from Winchester(IIRC) used in their Etron-X rifle rounds,but the rifle uses 150V to fire the primer.
(the rifle has a DC-DC boost converter built into it.)
-- Jim Yanik jyanik at kua.net
If they are like the CO2 cannisters I have seen, then the seal and the body are both steel, and probably in too good thermal contact to be able to melt just the seal without heating the whole cannister. In that case it may explode which is not very nice if you are nearby. I have known kids to light firelighters underneath these cannisters to blow holes in the side of metal garbage cans. It would be a hazard to eyesight if nothing else.
Chris
When the unit hit the ocean a salt water battery would activate the firing mechanism and inflate a bag so that the RF transmitter would float on the surface while the sonar sensors dangled 100m below on a tethered cable. The antenna was inside the bag too, so when the bag inflated the antenna was pulled straight up. After a set number of hours use the software would burn another resistor attached to the side of the bag, this would puncture the bag and cause the buoy to sink to the bottom. Can't have those Russian fishing trawlers picking up the military sonarbuoys now can we? Yep, the ocean is unfortunately littered with tens of thousands of these things :-(
Dave :)
rapped
Not all of them sink.
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