Air tanks legal on both sides of 60 psi regulator

[marccenter]

Dear CD,

I was inspecting a team at Centerline and came across a team that had air tanks on both sides of the 60 psi regulator. Questions?

1) Is this configuration legal? I assumed so.

2) The FRC pneumatics manual only shows one tank before the regulator. If the configuration is legal can someone change the manual in the future to show an air tank before and after the 60 psi working regulator to show other inspectors that this is legal?

3) Is the advantage to this tank configuration speed to the pneumatic actuators because the air has already passed through the potentially restrictive regulator? If so, is there a rule of thumb of using tanks before and after the regulator for maximum benefit that anyone knows about?

[Domtech]

As far as I read the rules it is legal.

Out team has done it before on a pneumatic catapult. There were 2 1.5 inch bore cylinders on the catapult that each had their own low side tank and solenoid.

It eliminates the flow restriction of the regulator and makes the solenoid the sole limiting factor.

[jee7s]

Absolutely legal. R83 allows for "storage tanks" (yes, it's plural in the manual) upstream from the regulator. Additionally, the tanks need to be compliant with R75, R76, and R77-K.

Tanks on the "high side" before the regulator store more energy per tank than those after the regulator. This reduces compressor short cycling. In a 2 minute match, that means the compressor may not have to run at all. The "low side" tanks allow for faster actuation. The regulator is most definitely restrictive.

Rules of thumb? Depends on the setup. If the compressor is constantly running, then more tanks before the regulator. If the actuation is sluggish and the regulated pressure takes a long time (more than a few seconds) to recover, then more tanks after the regulator. Side effect is that more tanks means more time to charge which means a longer initial compressor run time. But, since you can charge the system before a match, a well sealed system shouldn't encounter a problem if you allow for enough initial charge time.

[Greg Needel]

having a tank on the 60PSI side of the regulator is totally legal and yes it does speed up actuation as you are limited to the flow rate of the regulator otherwise.

It is a very common thing in FRC.


Greg

[FrankJ]

R77K allows storage tanks. No mention of being limited to one side of the regulator or the other.

R83 specifically allows the tanks on the storage side. The diaphragm for R86 shows the storage tanks on the working pressure side.

A reasonably astute person should conclude that the storage tanks are legal on both sides of the regulator.

[Al Skierkiewicz]

Marc,
All of the above are correct. R83 specifies what can be in the high pressure side not what must be in the high pressure side. It is a little confusing when you first look at it. In reading the rules for off board compressors, it is possible for the pressure regulator to be off board and that implies that storage must be in the low pressure side on the robot.