pic: Compressor Backpack

[Jon Stratis]

Originally Posted by rtfgnow

This might help you.

If you have a large air tank off the robot and use the robot compressor to fill it the morning of the competition, you could then use air from this tank to pre-fill your onboard tanks before each match. This would still meet the requirement that all air comes from the one compressor and allow you to hit a higher psi before starting your compressor to finish filling the tanks.

I do not believe there is a rule stating that air cannot be temporarily stored off the robot.

R70:

“Stored” air pressure on the ROBOT must be no greater than 120 psi. No stored air pressure intended for the ROBOT may be located off-board the ROBOT.

Emphasis mine.

Honestly, this backpack scares me from a safety perspective. What happens to the unlucky person wearing it if a tank should explode? As an LRI, I would insist it be removed from the venue, and I bet the UL Safety advisors would agree.

[JamesCH95]

Originally Posted by Jon Stratis

R70:

Emphasis mine.

Honestly, this backpack scares me from a safety perspective. What happens to the unlucky person wearing it if a tank should explode? As an LRI, I would insist it be removed from the venue, and I bet the UL Safety advisors would agree.

This. This times all of it. As a participant at an event I would want that removed. Plastic air tanks scare the bejesus out of me, mostly because I know first-hand how much energy and how much shrapnel they make.

If the pack got dropped while it was pressurized really bad things could happen. Please do not use this device, ever. I know it seems cool, but it's just asking for a disaster.

[evanperryg]

It's really, really cool in concept. Pretty much anything turned into a backpack is pretty awesome, and you've obviously made something that serves a very good purpose. I agree, though, about the safety problem. Nobody can stop you from using it in your shop, but i'd suggest using metal air tanks for something like this.

[Rosiebotboss]

I agree with Jon.

At LRI training at HQ in early Jan, one of our fellow CMP LRI who works at an Army Testing Lab hired an intern to test the most common plastic tanks available to FIRST teams. The results for the black Clippard tanks was good. The white Clippard tanks (See the Manual for the exact p/n) were ruled illegal after several failures during the season and the resultant testing this summer at the Army Lab. And if I remember right, the performance deteriorated when damaged, nicked or abused, even slightly.

Kudos for thinking outside the box, but you won't see one being used on my team or at my event. Period. End of story.

[Nyle]

Not all white plastic air tanks are the clippard ones
If I'm not mistaken, the air tanks in the picture are, in fact, from pneuaire, not clippard. Not that that makes it a good idea.

[Dale]

(deleted)

[GeeTwo]

If the goal is to have a way to charge the tank for practice, it would be much simpler to use a single A/C air compressor than four or more 12V ones.

• Include a tee somewhere in your high-pressure side, just on the tank side of the pressure relief valve so that relief valve will function as a safety.
• For competition, the third branch of the tee will be capped with a solid plug.
• For practice, replace the solid plug with a vent plug, with a quick disconnect on the open end. Keep this vent plug closed except when externally charging.
• To do an external charge:
  • attach the external compressor at the quick disconnect
  • open the extra vent plug
  • turn on the compressor
  • When you reach the desired pressure (or the relief valve vents), turn off the compressor
  • close the extra vent plug
  • disconnect the quick disconnect fitting

[SoMe_DuDe904]

Originally Posted by Jon Stratis

R70:

Emphasis mine.

Honestly, this backpack scares me from a safety perspective. What happens to the unlucky person wearing it if a tank should explode? As an LRI, I would insist it be removed from the venue, and I bet the UL Safety advisors would agree.

You beat me to it Jon. Those white tanks fail regularly if even slightly nicked or damaged. I saw one go off last year on the field and it sounded like a grenade going off. The plastic shards from an exploded tank would be a hazard not only to the wearer but those around him.

That looks super dangerous.

[bEdhEd]

I was just thinking about this last night, and we should at least encase the entire pack in a sheet of some thick polycarbonate, or some other method of keeping everything inside the pack in the event of any catastrophic failure. We should also replace the tanks with their metal equivalents.

I did mention that this pack is unfinished, and still requires some more safety features. We just needed something built to use for practice, and plastic tanks are what we had on hand.

If this is ever used, it is easily depressurizable for wearer movement to help reduce any accidents. This is only intended for use in safety glass areas around the robot when the robot is running and only when it is needed.

Having a member of our team walking around an event with a pressurized pneumatic backpack is just plain idiotic, and is not our intent with this system.

We don't intend to keep it pressurized for any extended length of time; only when we need to repressurize the robot for practice or testing.

Perhaps a tankless backpack may be the best option for safety, so pressurized air does not get stored in the pack at all.

If we deem this pack too unsafe still, we will make sure to keep it out of an event. Thank you all for your concern. I'm also all about safety, and I want to do my best to help make this pack safer for my team members and every volunteer, student, mentor, and attendee at an event, if that's possible.

[Foster]

It's a great out of the box idea, so you should feel great about that.

I think you got great rules feedback, with some redesign and some Q&A responses you'll have a working system. Metal tanks, shroud, etc are the first steps.

Remember, they laughed at Einstein, and now he has a field named after him.

You can always display it as a "future project" at events. Without air it's not a safety problem

[SoMe_DuDe904]

Originally Posted by bEdhEd

I was just thinking about this last night, and we should at least encase the entire pack in a sheet of some thick polycarbonate, or some other method of keeping everything inside the pack in the event of any catastrophic failure. We should also replace the tanks with their metal equivalents.

I did mention that this pack is unfinished, and still requires some more safety features. We just needed something built to use for practice, and plastic tanks are what we had on hand.

If this is ever used, it is easily depressurizable for wearer movement to help reduce any accidents. This is only intended for use in safety glass areas around the robot when the robot is running and only when it is needed.

Having a member of our team walking around an event with a pressurized pneumatic backpack is just plain idiotic, and is not our intent with this system.

We don't intend to keep it pressurized for any extended length of time; only when we need to repressurize the robot for practice or testing.

If we deem this pack too unsafe still, we will make sure to keep it out of an event. Thank you all for your concern. I'm also all about safety, and I want to do my best to help make this pack safer for my team members and every volunteer, student, mentor, and attendee at an event, if that's possible.

http://www.chiefdelphi.com/forums/at...2&d=1394474926

[Jon Stratis]

Originally Posted by bEdhEd

I was just thinking about this last night, and we should at least encase the entire pack in a sheet of some thick polycarbonate, or some other method of keeping everything inside the pack in the event of any catastrophic failure. We should also replace the tanks with their metal equivalents.

I did mention that this pack is unfinished, and still requires some more safety features. We just needed something built to use for practice, and plastic tanks are what we had on hand.

If this is ever used, it is easily depressurizable for wearer movement to help reduce any accidents. This is only intended for use in safety glass areas around the robot when the robot is running and only when it is needed.

Having a member of our team walking around an event with a pressurized pneumatic backpack is just plain idiotic, and is not our intent with this system.

We don't intend to keep it pressurized for any extended length of time; only when we need to repressurize the robot for practice or testing.

If we deem this pack too unsafe still, we will make sure to keep it out of an event. Thank you all for your concern. I'm also all about safety, and I want to do my best to help make this pack safer for my team members and every volunteer, student, mentor, and attendee at an event, if that's possible.

If you he seen the videos Dana, myself, and the rest of the LRI's saw at training, you probably wouldn't think some lexan would be enough. When these things go off, there is a huge amount or force and speed behind them.

I also want to add that directly connecting it to a battery, as it appears in the picture, is extremely dangerous and could very easily lead to an over-pressurization situation. That's why the rules clearly state the compressor has to be controlled by the robot.

[bEdhEd]

Originally Posted by Jon Stratis

If you he seen the videos Dana, myself, and the rest of the LRI's saw at training, you probably wouldn't think some lexan would be enough. When these things go off, there is a huge amount or force and speed behind them.

I also want to add that directly connecting it to a battery, as it appears in the picture, is extremely dangerous and could very easily lead to an over-pressurization situation. That's why the rules clearly state the compressor has to be controlled by the robot.

Again, I have to say that this compressor pack is unfinished and will have a pressure switch and relay. The tanks are being replaced with metal ones. We can opt for a carbon fiber shell if that would be effective, or get rid of tanks altogether. My thought wasn't just "some lexan" but a sheet .25 inches thick, which I think would be enough for high impact, but I'd have to see the videos that you mentioned to really get an idea. My objective at this point isn't necessarily to try to get it "safe enough" for an event, but get it "safe enough" for personal shop use.

I'm open to more suggestions to make this safer for non-event use, since the chances of using this at an event are low, and out of courtesy, it's best to keep it out of the pits and arena at all times.

[doctorflems]

Originally Posted by Jon Stratis

R70:

Emphasis mine.

Honestly, this backpack scares me from a safety perspective. What happens to the unlucky person wearing it if a tank should explode? As an LRI, I would insist it be removed from the venue, and I bet the UL Safety advisors would agree.

The solution to that safety issue is to put an OPV at every stage of the system, including one at each end of the tank, and set to 65% of the tank's pressure rating. This way, you have a redundant safety mechanism with about a 50% safety margin. With four tanks, you do this to each tank. In the case that a tank does fail, the frame of the pack should be designed to at least somewhat protect the user.