D420! How about that?

[rsingler]

Maybee i missunderstand you, but have Poseidon ever made any piston regulators?

Nope.

 

[buddhasummer]

Hi I also bought the new D420, I opened it to inspect it, I noticed that the lever (37) is above the case (15), about 1 mm, touching the diaphragm (38), I read in your comments , that it is better that the lever (37) must be 1/2 mm inside the case (15), so my question to lower the lever (37) what should I do, unscrew the screw (16), or unscrew the nut (24)? thanks .

Screw (16)

Do not touch nut (24) unless you want to disassemble stem assy, which you do not.

Are you checking lever whilst reg pressurized or unpressurized? Do it under pressure.

 

[buddhasummer]

Off topic:

Someone I emailed responded with this message, we were talking about the current crazy situation. I though it was beautiful, in a sad/hopeful kind of way:

"Yes crazy where a world changing virus that makes us struggle for breath... and stops us breathing.... is enabling the world to breathe again.
Thought for the day"

Take care everyone.
Simon

 

[Couv]

Are you checking lever whilst reg pressurized or unpressurized? Do it under pressure.

Why would a center balanced poppet's position change when pressurized/not pressurized?

 

[buddhasummer]

No idea, but it does I believe. I'm not that smart, maybe Rob can explain the mechanism. Lever height certainly changes between being pressurized and not.

@rsingler

 

[buddhasummer]

You've got me doubting myself now. Hmmm... I'll get out now and leave it to Rob for perhaps a correct and logical explanation. I'm wrong more than I'm right.

 

[Couv]

You've got me doubting myself now.

Don't doubt yourself. If the lever height changes, it changes. I just want to know why.

BTW check you email.

 

[buddhasummer]

Don't doubt yourself. If the lever height changes, it changes. I just want to know why.

BTW check you email.

Check yours, I replied. Good news for a change, happy about that.

Added: just saw your second email, have replied.

 

[rsingler]

Yes, lever drops 1mm on pressurization.
Correct position is coplanar with the case rim when pressurized, and just peeking above when not.
You can do the math, but with a 25mm lever arm, and a foot lever length of 2mm, and an angular displacement of 1.8°, we're talking seat de-compression of only thousandths of a millimeter, as the reg drifts toward freeflow.

EDIT: I got bored enough to do tan(1.8 degrees).The maths amount to seat decompression of 6/100th's of a millimeter. It's not thousandth's, but it's still small.

Though center balanced, the balancing is not zero difference. The stem oring land diameter is, I think, fractionally less than the orifice diameter. If you raise IP high enough, the reg will leak. As the seat rises, the lever falls (and EDIT: the seat is decompressed 0.06 mm).

Pressure off:

Pressure on:

 

[buddhasummer]

Yes, lever drops 1mm on pressurization.
Correct position is coplanar with the case rim when pressurized, and just peeking above when not.
You can do the math, but with a 25mm lever arm, and a foot lever length of 2mm, and an angular displacement of 1-2°, we're talking seat compression by the rather sharp knife edge common to the D-series of only thousandths of a millimeter.

Pressure off:
View attachment 584565
Pressure on:
View attachment 584566

You're a smart man Rob.