how much flow thru a sae8 fitting

muddstopper · Jul 30, 2013

I have been building a firewood processor off and on for about a year now. Buying used parts when i can find them cheap. Anyways, today i was at northertool and saw they had a 5inborex24inch stroke 3000psi cylinder for sale for $269. Its their nortrac brand. Anyways, I had planned on a 28gpm 2stage pump for the splitter portion of the processor and the cylinder only has 3/4-16 ports. I am just wondering if that size port will flow 28gpm on the low pressure side of the pump, without causing to much heat or restriction. Not sure the flow rate under high pressure, guessing 14gpm or about half of the low pressure flow. No use in buying a 28gpm pump if the cylinder cant use the flow. I already bought the cylinder, figued I could use it on my regular wood splitter if nothing else. I can replace the small ports with bigger if I have to, but dont want to if I can get by without larger ports.

J_J · Jul 30, 2013

You need 1 in to flow 28 GPM at 15 fps.

3/4 in will flow about about 18 GPM.

Return lines using 28 GPM need 1 1/4 in at 10 fps flow.

https://www.google.com/url?sa=t&rct...=4gu5qj1C2wFW2uLHya121A&bvm=bv.49967636,d.aWM

muddstopper · Jul 30, 2013

JJ, somehow I knew you where going to say that. I already suspected it, but just had to have someone confirm. For the processor, I need really fast cycle times so it looks like I will just remove the small ports and add larger ones. So much for warranty. And i was wrong about the high pressure flow rates on the 2stage. Its only 7gpm, not 14gpm. At anyrate, I will try this cylinder out on my current splitter, as is, and put the 4in cylinder back on the dump trailer where I robbed it from.

bigdeano · Jul 30, 2013

I'd just use the cylinder the way it is. It won't cause enough pressure drop to be noticable. The difference in pressure drop between 3' of 1" hose and 3/4" hose is only 4 psi at 28 gpm. I used this calculator.

Fluid Flow Calculator I used 28 for viscosity, from "viscosity data" to the left of the calculator.

oldnslo · Jul 31, 2013

The hole through the fitting will be the limiting factor. I would guess that through hole diameter would be around 7/16".

At 28 GPM flow through a 7/16" orifice the pressure drop is around 50 PSI. To keep velocities and line losses to minimum I would step up the bling end hose size to at 3/4" since your return flows will higher.

bigdeano · Jul 31, 2013

For some reason I was thinking 3/4 pipe threads. Disregard everything I said. Darn, getting old.

J_J · Jul 31, 2013

I found this for hyd tubing, so it appears that everything stated, does not mean it is the same.

1/4" x 0.035 0.180" 3850
3/8" x 0.049 0.277" 3593
1/2" x 0.049 0.402" 2695
1/2" x 0.065 0.370" 3575
5/8" x 0.065 0.495" 2860
3/4" x 0.083 0.584" 3043
1" x 0.049 0.902" 1347
1" x 0.065 0.870" 1787
1" x 0.083 0.834" 2282

You would think if you asked for a 1 in whatever, you would get 1 in whatever.

oldnslo · Jul 31, 2013

Tubing is measured or sized by the OD and wall thickness. So thicker wall means smaller ID. The same is true for pipe. schedule 40 has the same OD as schedule 160. example: 3/4" schedule 40 ID is .824 while schedule 160 ID is .614.

Even hose hoses in some case are misleading. I have seen hoses called -16 or one inch that had 7/8" ID Vs normal 1" ID.

muddstopper · Jul 31, 2013

I'll measure the inside dia of the ports when I get home for the weekend. I am thinking that 3/4-16 sae would mean 3/4inside dia. Once you screw a #8 sae fitting into the port, the inside dia of the #8 fitting would be the limiting factor. This dia I believe should be close to 1/2in, but hey, I've been wrong before.

BukitCase · Jul 31, 2013

The good news is, you get the chance to be wrong AGAIN

Just kidding, from a guy who gets LOTSA chances at that distinction

Check this out

http://www.discounthydraulichose.com/v/vspfiles/downloadables/thread_guide.pdf

Look at the chart on page 8, straight thread O-ring fittings (SAE or ORB)

SAE 08, THREAD size is 3/4-16, nominal PORT size is 1/2" - so at least for SAE, it appears that the dash # may be actual port usable diameter (in 1/16" increments - 08 = 8/16, = 1/2")

Now I gotta get off my tush and go work on my brush fork project - I'm sure it'll take at least 3 minutes to "be wrong at least one more time (in the next half-hour, that is )

...Steve