Pneumatic Regulators from Automation Direct

[FrankJ]

Thanks for your input Katie. I certainly am not trying to shoot the messenger.

But to be honest I rather have the ambiguous definition rather than a poorly (at least in my mind) thought out answer Q&A occasionally gives on these kind of questions.

I am solving it on my team's robot by using the recommended regulator. On the robots I inspect, I will follow my LRI's lead. One of the advantages of being a flunky inspector is I kick the hard questions to up to management.

As an aside. It is poor practice to specify parts like this that are going to be used at the top of their range. I always take the pressure from inexpensive regulators and small diameter, uncalibrated pressure gauges with a grain of salt anyway.

[martin417]

So,

If I use the "recommended" regulator Norgren regulator P/N: R07-100-RNEA, does that mean I can use it outside its design range of 5-50 PSI and push it up to 60 PSI? Or am I limited to 50 PSI regardless of what the rules say?

What if I use the KOP regulator from a previous year's KOP? Are they legal? Is any of this going to be communicated to teams, or will most teams just be ruled illegal at inspection? Will the pit admin have a supply of legal regulators, or will teams just be told they must remove all pneumatics from their robot because no legal regulators are available?

Either there has been some miss-communication, or FIRST has royally screwed up. (again).

[Al Skierkiewicz]

C'mon Martin. The graph for this regulator shows it going to 60 psi just like it always has.

[Holtzman]

Originally Posted by Al Skierkiewicz

C'mon Martin. The graph for this regulator shows it going to 60 psi just like it always has.

Al,

If you read the data sheet for this regulator found here ( http://cdn.norgren.com/pdf/Mini_Gene...R07,%20R46.pdf ) It states...

Adjustment Ranges* Substitute
1 to 10 psig (0.1 to 0.7 bar) A
5 to 50 psig (0.3 to 3.5 bar) E
5 to 100 psig (0.3 to 7 bar) K
5 to 125 psig (0.3 to 8.6 bar) L


It also states at the bottom of the first page...

* Outlet pressure can be adjusted to pressures in excess of, and less than, those specified.
Do not use these units to control pressures outside of the specified ranges.


In practice, we all know this regulator works just fine for FRC applications, along with many other suitable regulators as well, but according to this, we really should be recommending R07-100-RNKA. Thats probably a big part of why teams have a hard time keeping that particular regulator set to exactly 60psi.

[martin417]

Originally Posted by Al Skierkiewicz

C'mon Martin. The graph for this regulator shows it going to 60 psi just like it always has.

I am not sure what graph you are referring to Al. This is the only spec sheet I have found, and it only has a graph for flow characteristics of a 1/4" inlet 5-100 PSI version.

The 100-RNEA from the part number means that this one is a 1/8" port standard, Relieving, non-gauge, PTF threaded, regulator, adjustable from 5 to 50 PSI. There is also a note that states:

Outlet pressure can be adjusted to pressures in excess of, and less than, those specified. Do not use these units to control pressure outside of the specified ranges

I don't think it could be more clear.

[martin417]

I am familiar with gas pressure regulators, having designed (and hold patents for) several. I would never recommend using a regulator at or near the extremes of its adjustment range, much less above it. An adjustable regulator works best near the middle of its adjustment range, and its performance is worst at the extremes.

If I was specifying an adjustable regulator for use at 60 PSI, I would specify one that had 60 PSI as the middle of its adjustment range, 0-120, 40-80, 30-90, etc.

I would never want to use one that had 60 PSI as its extreme setting, or worse above its extreme setting.

I am not sure what the goal is here, unless they are worried about a team cheating by changing the pressure on the field.

[Paul Copioli]

I, too have expansive experience with fluid regulators, both air and paint solvent and 100% agree with Martin on this.

We are using the Automation Direct regulator and it performs MUCH better than the Norgren regulator. It's specifications meet all the FRC rules, from our interpretation and past enforcement of this rule.

If the Inspectors want clarification, then they should seek it from FIRST and be clear in their intentions of calling the rule.

Al,

I think it is prudent if you make an actual ruling on this specific regulator. Right now, 1296 is using it in Palmetto and passed inspection. This regulator was used last year without incident. Can you please lead the way in reasonableness and urge for extreme clarification on this? You have always been extremely reasonable when dealing with teams and clarification on this pretty simple issue seams like it should be a no brainer.

Thanks,
Paul

[Al Skierkiewicz]

Paul,
I am simply referring to a part that has been either recommended or required for many years (at least to 2010). Why is everyone so opposed to using a tried and true device? The rules have not changed that much, using nearly identical language...

R82 “Working” air pressure on the ROBOT must be no greater than 60 psi and must be provided through a single primary adjustable, relieving, pressure regulator.

Norgren regulator P/N: R07-100-RNEA or Monnier P/N: 101-3002-1 recommended.

Not "required".

[AllenGregoryIV]

Originally Posted by Al Skierkiewicz

Not "required".

Al, I think Paul wants a clear cut answer on weather a regulator like this one (http://www.automationdirect.com/adc/...Series)/AR-213) is legal. I don't think anyone is trying to prevent teams from using the Norgen regulator.

[Aren_Hill]

As Paul stated, we are currently competing with the tiny regulator from automation direct, we used it because it is very small, light, and cheap.

My brother Kellen used these last year as well with 1746, they are a proven technology and I enjoy the benefits and do not see why anyone would use anything else.

Actually, pulled the catapult off yesterday, so there are no pneumatics on the Bot, but it did pass inspection.
-Aren

[Chris_Elston]

Originally Posted by Al Skierkiewicz

Why is everyone so opposed to using a tried and true device?

We chose the Automation Direct one because it has an integrated gauge. In the beginning of the season, you could not get the white gauge from AndyMark, so we went looking somewhere else. Now that gauge is in stock. Also, it seems the gauge needle breaks for some reason in the white or norgen gauge, we've had several problems with the gauges not the regulator. So, like about 1/2 the people on this thread is seemed to us it was a legal device, didn't even think twice about it, we printed the spec sheet and have it in the same book as the robot bag and tag form ready to show the inspectors. That was why we went looking at something else.

[Paul Copioli]

Al,

You asked a direct question about the Norgren valve and I will answer it.

we have had terrible hysteresis problems with that valve and it is mostly related to it being used at the extreme of its working envelope.

Also, for this season the fact that the Automation Direct valve is so small is a huge bonus.

Paul

[Tristan Lall]

I'm inclined to continue using the past interpretation of the rule to resolve the Norgren issue in favour of legality. Since a Norgren R07-100-RNEA regulator can frequently¹ be adjusted above 50 lb/in² (the manufacturer's operating limit²) and even above 60 lb/in² (the R77-I limit) using the provided control knob, and FIRST should know this, I would interpret the "maximum outlet pressure" to mean the maximum non-transient pressure at the outlet given a certain user-adjusted setting, rather than the manufacturer's published operating limits or proof limits. This also permits R75 to be read without conflict: the "working pressure" referenced there should be interpreted in terms of the possible range of input pressures, not the adjustment range of the outlet.

Using that logic, the AutomationDirect valve, the Nitra AR-213 is also legal. For R77-I, you must adjust its outlet to 60 lb/in² or less, and the datasheet states this is possible. For R75, the "working pressure" at the inlet should be no more than 145 lb/in² if like the Norgren, you may operate it in excess of recommendations, or no more than 130 lb/in² if you must stay within the manufacturer's range. Either figure satisfies R75.

Also, for anyone concerned about unsafe failure of the regulator, Nitra conveniently provides proof limits: below 215 lb/in², you should not expect the regulator to fail catastrophically.

For better or worse, guidance provided to LRIs is not inherently a rule, and cannot be enforced.

¹I don't know what the production variation is on the physical limit of adjustment, so perhaps I'm relying on outliers to reach that impression.
² For regular customers at least. I seem to recall, but can't document, a Q&A from the early 2000s alluding to Norgren telling FIRST that operating this regulator up to 60 lb/in² was acceptable.

[martin417]

Has anybody submitted a Q&A on this topic? Would be nice to get clarification before the next event.

[Holtzman]

Originally Posted by martin417

Has anybody submitted a Q&A on this topic? Would be nice to get clarification before the next event.

Yes.