1.1 Pump (am-3227) Really an improvement?

[Jeffrafa]

I noticed AndyMark has come out with a new compressor as an alternate to the Viair 00090.

The primary claims about it seem to be that it has a higher 1.1 CFM output (legal limit per 2016 R79), and that it has a higher rated duty cycle (15% vs 9% on the Viair).

A quick glance at some of the specifications makes me doubt the value here though.

1.1 Pump:

• 3.37 lbs
• 15% Duty Cycle
• 1.1 cfm @ 0 psi
• 0.26 cfm @ 100psi
• Dimensions: 3.27"x6.75"x5.25"
• ~31 sec - Claimed time to fill (1) 574ml tank 0-110 psi

Viair 090:

• 2.4 lbs
• 9% Duty Cycle
• 0.88 cfm @ 0 psi
• 0.39 cfm @ 100psi
• Dimensions: 2.11"x4.53"x5.94"
• ~13 sec - Claimed time to fill (1) 574ml tank 0-120 psi

Based on the listed specifications, the new one has a little better duty cycle - which may make it a little more reliable. Otherwise it weighs nearly a pound more, takes up more space, and has ~30% less volume output at 100psi - where it matters for topping off during the match. Even the stated fill times for a tank are worse than the Viair.

I like the look of the larger heatsink, but between the weight penalty and the lower ouptut at pressure, I'm not seeing the advantage.

Am I missing something here?

[Billfred]

I've had both in my hands--the difference in size isn't that significant (especially compared to the 100%-duty-cycle Viair pump 4901 used in 2015...), though obviously a pound is a pound.

We just got the 1.1 pump page up today, and it's entirely possible that we had a typo because that is a head-scratcher. I've got emails in to investigate the concerns you bring up (which are absolutely fair ones!).

[s-neff]

I was excited about it, and then my student Ruben pointed out the same thing.

We charted the performance data for comparison, the cross-over point is at 30psi. I don't think our system pressure has ever been that low without leaks involved.
(Having trouble uploading the image...)

[cscottm]

2502 used a 1.1 CFM pump this year (Stronghold) and without it we would not have been as functional as we were. We sucked through a lot of air with our robot, and the extra .22 cfm from the .88 cfm that we tried before saved us a lot of hassle, and a number of issues we were having were avoidable.

so IMO yes, they are that much better

But when they say they get hot, they get really $@#$@#$@#$@# hot. (we melted some pneumatic tubing)

[Jeffrafa]

Originally Posted by Billfred

I've had both in my hands--the difference in size isn't that significant (especially compared to the 100%-duty-cycle Viair pump 4901 used in 2015...), though obviously a pound is a pound.

We just got the 1.1 pump page up today, and it's entirely possible that we had a typo because that is a head-scratcher. I've got emails in to investigate the concerns you bring up (which are absolutely fair ones!).

Looking again I noticed the metric stats for the 1.1 Pump are copy-paste identical to the Viair 00090 specifications page.

I appreciate you following up via email to look into this. Hopefully all will be cleared up once the page is reviewed for accuracy.

I agree that the size difference is probably marginal - both are smaller (and lighter) than the Thomas compressors used in 2010 and earlier.

[AdamHeard]

Originally Posted by Billfred

I've had both in my hands--the difference in size isn't that significant (especially compared to the 100%-duty-cycle Viair pump 4901 used in 2015...), though obviously a pound is a pound.

We just got the 1.1 pump page up today, and it's entirely possible that we had a typo because that is a head-scratcher. I've got emails in to investigate the concerns you bring up (which are absolutely fair ones!).

What would be very helpful is if AndyMark tests the fill time for both and posts that information for a given volume.

[cbale2000]

I'm partial to the 100% duty cycle compressors myself, those light-duty compressors heat up way too much.

BTW, this is a good place to compare and find different compressor options (as well as other parts):
http://findrobotparts.com/compressors/

[AlexanderLuke]

Originally Posted by AdamHeard

What would be very helpful is if AndyMark tests the fill time for both and posts that information for a given volume.

Originally Posted by cbale2000

BTW, this is a good place to compare and find different compressor options (as well as other parts):
http://findrobotparts.com/compressors/

How about a resource from two of the vendors we all use most?

motors.vex.com ..... The motor specifics that we use to design mechanisms.

and

pneumatics.andymark.com ..... People have trouble with spelling.
air.andymark.com ..... Sounds a bit too simple.
airmatics.andymark.com ..... Kinda catchy, but kinda strange.
(In short, I have not settled on a name.)

On this Andymark page, you can find specs and pricing on the most common FRC legal compressors out there. Teams can send in recommendations to Andymark about one that they use that is not featured on the site, and Andymark can add to the page or even sell it if they wish. There would be options to compare fill times for given sets of volumes across multiple compressors. Want more information? You can click on any compressor listed and see pricing, recommended vendors, and performance sheets. While we are at it, how about some nice looking performance graphs for visuals too.


Just an idea...

[Tom Line]

Originally Posted by cscottm

2502 used a 1.1 CFM pump this year (Stronghold) and without it we would not have been as functional as we were. We sucked through a lot of air with our robot, and the extra .22 cfm from the .88 cfm that we tried before saved us a lot of hassle, and a number of issues we were having were avoidable.

so IMO yes, they are that much better

But when they say they get hot, they get really $@#$@#$@#$@# hot. (we melted some pneumatic tubing)

Which pump was it that you used? Did you quantify / test it in some manner to prove it was better than the Viair?

[Nuttyman54]

Curious also that AndyMark's specs for the Viair 90C don't match the specs posted on Viair's website, which pegs it as a 1.03 CFM at 0 psig.

Some clarity would be helpful, right now it looks like the AM 1.1 pump only beats the Viair 90C on duty cycle.

[AllenGregoryIV]

Originally Posted by Nuttyman54

Curious also that AndyMark's specs for the Viair 90C don't match the specs posted on Viair's website, which pegs it as a 1.03 CFM at 0 psig.

Some clarity would be helpful, right now it looks like the AM 1.1 pump only beats the Viair 90C on duty cycle.

Viair lists all their compressor stats at 13.8V now. It's a problem.

[Gdeaver]

This year we strapped a 40 x 20 mm fan to the VAIR compressor head. Heat was no longer a problem.

[jwfoss]

Originally Posted by AllenGregoryIV

Viair lists all their compressor stats at 13.8V now. It's a problem.

Agreed, we have a 98c in the shop and the sticker shows the 12v rating is legal, but the website data at 13.8v showing its over the 1.1. I would love to see FRC increase the cfm rating or at least give us a limit at 13.8v so we can look at the other Viairs.

Perhaps if AM did testing on the Viair product line at 12v we could site that to justify compressor selection?

[JPBlacksmiths]

Originally Posted by Gdeaver

This year we strapped a 40 x 20 mm fan to the VAIR compressor head. Heat was no longer a problem.

How did you attach this fan being that the compressor doesn't have mounting holes for a fan? (Or at least i'm pretty sure it doesn't)

[cbale2000]

Originally Posted by JPBlacksmiths

How did you attach this fan being that the compressor doesn't have mounting holes for a fan? (Or at least i'm pretty sure it doesn't)

There's actually pictures of it here on CD I think if you browse the photos section a while. We did something similar to this on our 2011 bot, but we just mounted one of the 120mm fans next to the compressor so that air blew across it. The improvement in heat dissipation was actually pretty drastic: Test Results

That said, even if an external fan can help keep a compressor tolerably cool, if you're running a low duty cycle compressor almost constantly throughout a match, you're still using it beyond it's designed limits. I would also suspect that you will still loose efficiency over prolonged use this way due to internal heating that isn't adequately dissipated by external fans.

You can actually think about it a bit like how we think of motors. The 775pro motor is a great, strong little motor, but too much heat (generally generated from stalling the motor or extended use) will cause it too loose efficiency and burn out, and while blowing a fan across it might help, it won't stop the problem. Alternatively, a CIM motor can run continuously even after substantial heat build-up (even in stall condition) without a fan with little to no damage due to its increased thermal mass.
Essentially <15% duty cycle compressors are 775pros and ~100% duty cycle compressors are CIMs.