Quote:
Originally Posted by NickE
From our team website:
1" NPT MAC Solenoid Valve at ~17.0 cV Flow Capacity with a 23 ms Response Time.
For the increased reliability, safety, performance and peace of mind, buying a quality valve was well worth the investment. |
An ASCO 8210G004 12 VDC solenoid valve is $218 LIST. You can probably get this cheaper if you go to a distributor and explain that you are a school related team. This is a 1" NPT valve, with a full bore orifice. If you step up to the 1 1/2" NPT 8210G022 12VDC solenoid valve, you get a much higher Cv (22.5 vs 13) but your price goes up to $405.
Both of these valves are only rated for 125 PSIG, so be careful not to try climbing above that. The biggest thing with building the air cannon is making sure that you can get an appropriate amount of air into the barrel in as short amount of time as possible. That's why it seems that higher pressures are better. You'll only need a limited amount of pressure if you can get the flow high enough. This of course also depends on your secondary accumulator (tank) volume. Make it too small and you won't have enough air to accelerate the projectile to a proper velocity, make it too large and you are just wasting energy (assuming equal barrel lengths).
A note on compressor usage: Do not expect kit compressors to last very long if you are using them constantly. They are surely not rated for anything higher than a 10-15% duty cycle. This means that they are only rated to run at the pressure rating for 10-15% of time. In other words, 6-9 minutes out of every hour. Running them more than that risks overheating the compressor and burning something out.