Can you heat a co2 ram ?

[andrewmahoney]

Hi everyone,Happy New Year!
My robot wedgie had a problem of freezing up after two or three flips,and i thought it a good idea to fit a heater on to the ram cylinder to defrost the piston,it works well increasing the amount of flips to around 20.
I realised at the last event,after proudly anouncing my invention that it was against fra rules.
If it is i am sorry for my mistake and will remove the heater.It seems the rule was intended to prevent the heating of co2 bottles,and i cant see any danger in heating the ram.I have noticed a few larger robots heat parts of there machines before a fight,so i guess this will effect them as well.
Any advice would help.
thanks Andy.M

[kane]

8.14. Pneumatic systems using heaters or pressure boosters are not permitted.

[maddox]

More heatsinks are an option, radiator fins are the only allowed , and passive means to get energy in the system to combat freezing.

And I do understand the possible mistake. I myself, even if I never used the heating methode, should have known better.
But Mentorn didnt allow bottleheaters.And the rest of the system had a handy arena heater with the flamepit.
This gave some of the seniors the wrong idea in the rules.

Fysicaly, there is no problem with heating the system. This should be protected by the 1000psi PRD.
Except the bottle, and even if the bottle is overheated the burst disk would prefent worse things.

As with all things concerning CO2, we full pressure users have to keep track of a few more,and much more restricting rules than any other robot builder. Spinners are the next runner uppers in this, and these machines are more restricted by the enviroment than by the rules themselfs.
Even if the old Mentorn Rules covered 99% of the potential problems with pneumatics.

[kane]

The best method I have come across so far is to restrict gas flow into the buffer. This allows the CO2 to boil off in the gas cylinder without pulling liquid through into the rest of the system causing freezing.

[typhoon_driver]

I wouldnt worry about the mistake. Everyone is always pushing the rules to their limit and attempting to exploit loopholes etc. If we didnt then there wouldnt be any development of the machines.

[woody]

Andrew ...Id suggest that your icing problem is caused by liquid co2 entering your system.... resolve this and you should have no need of a heater and also have more flips.

[maddox]

Woody, Andys system is not drawing liquid into the buffertank. There is a restrictor in the connection between bottle and collector.

The icing is normal for every high flow system, even with the bottle restricted.
The only way to enhance the system inside the rules is to add more heat exchange area and/or mass to draw heat from.

[mute]

Id agree with Woody, once the system chills down from the HP gas Id guess that liquid CO2 will pass more easilly hence it freezes up. The only way we found to get around it was put less gas in the bottle to give more vapour space - although we never ran with a buffer. Maybe a bigger buffer will help, or cut the flow rate to the rams back a bit?

[Mouldy]

i second kane..

In Turbulence mk1, we used to have high flow pipes going into the buffers from the regulator. The ram used to be icey at the end of a fight. But it never leaked co2 (until the reg blew) Replace what pipe you have there with some small stuff (6mm od pipe) and it should help keep everything abit warmer. including your buffer tanks. When you draw gas quickly, things WILL get cold, no matter what. The slower the flow, the warmer things will stay. The only part of your system that should be high flow is inbetween the buffer, the valve, and the ram.

[woody]

Id also suggest expanding any CO2 THROUGH the buffer ... end to end ....rather than simply adding a T piece .... thus any unwanted liquid expands in the buffer rather than being added to the flow from the buffer and on into the ram.

The internal bore of the main bottle valves ....that I have measured ... are fairly small and certainly in the case of a paintball tank tiny enough to constitute a restriction.

Paintball valves around 1/32
handwheel valves around 1/8 or 3mm ( feather size )