Team MedBots

[Bodge Job]

Re: Team MedBots

Screwed up? I thought it you were sopost to tighten it? Unless I'm just reading it wrong...

[Max]

Re: Team MedBots

Ok, I been trying to get it to work and the regulator is acting very strangly,
We've starting off the the end cap almost completely undone then screwing it on slowly until it got to the desired pressure. We then fired the ram and the pressure wouldnt go back up and stayed very low. We tighting up the end cap a very little bit further, dumped the system and pressure up (by gently turning in the valve on our fire extinguisher) then the pressure went off the scale in under a second and the ram fired with extreme force, we then dumped the excess gas and there was a lot more than usual in the pipes. We we not using a buffer tank but had very long pipes.

Can someone please tell me what I did wrong?

[Bodge Job]

Re: Team MedBots

Do it in the other direction, screw it up tight, so that it's at the lowest pressure, and slowly unscrew untill you've found the pressure you want. Or your over pressurising the system, and the gas can't flow back though the reg, so it remains at the high pressure.

[blazerbotics]

Re: Team MedBots

Screwing it tight will increase the pressure. Sound like your doing it right, im guessing its sucking liquid through, if your bottles laying flat you could do with a dip tube in it, as i had this problem with Ratchet. Next time you test it try it with the bottle standing up see if its any better. As for it not repressurising, the only thing i can think off is the reg is sticking, was the regulator cold?

[Max]

Re: Team MedBots

The bottle was standing upright, it was a fire extinguisher bottle. The regulator did get cold.

I am still trying to figure this out, is it the tighter the end cap is on the greater the pressure or is it the tighter the end cap is on the lower the pressure?

[Max]

Re: Team MedBots

Also how do people usually set their regulator? Do you just connect a pressure gauge straight into the regulator ?

[blazerbotics]

Re: Team MedBots

The bottle was standing upright, it was a fire extinguisher bottle. The regulator did get cold.

Fire extinguisher will have a dip tube, so your pulling liquid straight through, they it with the bottle upside down. You should be able to put the gauge directly on the reg. Unscrew the reg all the way out, then wind it in until you reach the desired pressure.

[maddox10]

Re: Team MedBots

No avarage gas regulator can cope with liquids.

By using the extinguisher upright, you're feeding liquid CO2 in the Trev.
If you did set it very low, the reg is closed. And won't let the liquid flow trough.
But a tad higher and the liquid will enter your setup. Depending on total volume in the setup, and the function of the low pressure relief valve, you can get ripping hoses or failing low pressure push locks/couplings, damaged valves , or the worst case, exploding buffers. (luckely you didn't have one)

Concerning pressure gauges and Trevor regulators.
The Trevor has 1 1/8 bsp outlet, that's the low pressure side. You'll need a T-piece (or 2) to have a dump/low pressure PRV and gauge on the basic setup.

[Max]

Re: Team MedBots

Can a prv be used more than once or is it like a burst valve on a bottle so you have to replace it?

[Shakey]

Re: Team MedBots

They can be used more than once. They are kind of like a regulator in how they work.

[Laser]

Re: Team MedBots

Hi, max

We had a play with our oneumatic system last week, and it all went well, one thing you may have to concern is that if you try and increase the pressure by turning the endcap when you have got it connected to the bottle and gas flowing throw it, is that it gets very hard and the high pressure seal may leak.

As for your higher pressure problem, when you turn on your bottle the pressure does go about 1 bar higher than the disired pressure as the reg was starting up, your PRV should blow then and your system should return to your desired pressure.

Have a look at my videos I took whilst during the testing:
http://www.youtube.com/watch?v=oKyUKFhF ... ature=plcp

[Bodge Job]

Re: Team MedBots

Oh sorry, got it wrong

[Max]

Re: Team MedBots

2 questions today,
Would 2mm steel be ok for base and armour? It would be well supported.

Also how do you full pressure flippers guys attach a pipe to your bottle, more specifically ones with a co2 nut type thread? I don't understand how you attach a pipe to the co2 nut.

[Bodge Job]

Re: Team MedBots

I think that 2mm will be way more than enough!

[Max]

Re: Team MedBots

Hi all,
I've spent the 3 hours just discussing with my dt teacher how my flipper design it wrong rather than getting on building it
But I do see his point, because the ram is mounted nearly horizontally the force going upwards should be almost zero (cosine of angle times force . if angle is 90 then times force by 0!)
He suggested using a elbow shaped linkage which should mean most the force goes up but it has a lot more parts to go wrong and break and it makes the robot bigger and using the ram in reverse so a bit less force and one of the pivots has to move in a slot.

Also he recons you only need 70mm movement at the tip but I think you want at least double that, what do you guys think?