NPT fittings as orifice?

[sprintcar]

Would you guys be kind enough help out?

The 8 GPM gear pump will supply ISO 150 synthetic oil -
Cold start ~ 40F (1510 cst / 7000 SUS)
normal operating temp ~ 170F ( 35cst / 165 SUS)
- to "flood" (not pressure feed) 3 roller bearings from a common manifold.

Each bearing requires a different flow rate with nominal rate as follows:
Brg A = 0.75 - 1.0 gpm
Brg B = 1.5 - 2.5 gpm
Brg C = 3.5 - 5.0 gpm < Extra flow is not a problem

The lines will be about equal length and the discharge nozzles can be sized as required.

Any suggestions on beginning nozzle sizes? Ideally, NPT fittings would make the best restriction but tubing or drilled restrictors can be used.

THANKS!!

















Thanks!!

Keep the wheels on the ground
Bob
showshine@aol.com

 

[scalleke]

Why ould you star with Oil this cold?

Can you not heat the oil up prior to starting the unit.

Best regards.

Scalleke

 

[sprintcar]

That should be about the worst case - units are outside and exposed (no building) and there are no heaters in the bearing assembly.

That's why I'm asking you experts!

Keep the wheels on the ground
Bob
showshine@aol.com

 

[MikeHalloran]

Sharp edged orifices (no burr, no chamfer, no radius) drilled in NPT fittings should work okay.

C = .250" dia 4.71 gpm
B = .177" dia 2.35 gpm
A = .112" dia 0.94 gpm

for water at room temperature, the manifold pressure would be ~17.5 psi






Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[sprintcar]

Mike
Is that corrected for the oil viscosity or just water flow?
Thanks

Keep the wheels on the ground
Bob
showshine@aol.com

 

[MikeHalloran]

That's for water, with no corrections.

I assume the gear pump has an internal relief valve; that should take care of the cold starts.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[sprintcar]

This pump doesn't have the relief since it will not be pumping against pressure other than the orifice. That was my concern when I ran the water orifice calculations it didn't seem like that would be enough for cold temps. I'm thinking maybe (2) 1/4 npt fittings and a 1/8 npt might be close enough?

Keep the wheels on the ground
Bob