Creating the Lightest Pneumatic System

[FrankJ]

Hi Ed:
Aside from being a supporter of First AutomationDirect is a next day delivery for you & they have good stock.
The AutomationDirect valves are legal this year (Cv.78) The nominal pressure rating is 20-115 PSI. The way I read the rules means a separate relief valve unless you have something that says otherwise.

R77-D. Solenoid valves that are rated for a maximum working pressure that is less than 125 psi rating mandated above are permitted, however if employed, an additional pressure relief valve must be added to the low pressure side of the main regulator. The additional relief valve must be set to a lower pressure than the maximum pressure rating for the solenoid valve,

One reason to use a double solenoid valve is for spring center. The center position can either block or connect the A & B ports. So the cylinder will stop or flop when the solenoids are not powered. Another reason would if you want the valve to stay in the position last set rather than a spring return to the "off" position.

[Mike Schreiber]

Originally Posted by FrankJ

Hi Ed:
Aside from being a supporter of First AutomationDirect is a next day delivery for you & they have good stock.
The AutomationDirect valves are legal this year (Cv.78) The nominal pressure rating is 20-115 PSI. The way I read the rules means a separate relief valve unless you have something that says otherwise.

Al,

My question isn't whether these valves are legal, it is whether I need to add the extra relief valve because the maximum working pressure is below 125 psi (R77D). The same question goes to these AutomationDirect valves. It doesn't make sense to me to add it because they will never operate above 60psi, but according to my interpretation of the rules I need it. I understand the difference between failure pressure and operating pressure, but which does "working" refer to? Are the SMC valves only okay because IFI has said they'll operate up to that pressure, and what about the varieties of SMC valves VexPro doesn't sell?

[nuttle]

Norgren 16-004-003 is a little lighter than the usual 16-004-011, but also allows you to omit a brass fitting (if you're using the new compressor). Likely not worth worrying over though. You can also get smaller pressure gauges that should be a little lighter, if you're really trying to save a little weight/space. I also like Clippard TV-2SP for the dump valve but I'm not sure if it saves any weight as I don't have one handy...

[Al Skierkiewicz]

Mike,
The specs are a little confusing. The way I read the sheet you linked, the pressure rating is recommended operating pressure. The sheet gives a range of 0.15 to 0.7 MPa but it does not specify a max operating pressure.