New built 3pt log splitter

[KennyG]

Can someone explain why pipe flow is more than hose flow.

Hydraulic Reference - hydraulic calculations, hydraulic equivalents, hydraulic conversions, convert measurements, flow capacities, hydraulic fittings, threads per inch, pipe threads, cylinder calculations, pump calculation, motor calculations, thread

Go to, FLOW CAPACITIES OF HYDRAULIC LINES

It's a result of surface friction. When you get into actual flow calculations, there are friction coefficients for carbon steel, stainless, copper, brass, etc., also values for new(clean) and used (dirty) as well as corroded. In general non-metallic materials are much rougher than metals. In addition to the friction itself,the rougher the surface, the quicker you will transition from laminar flow to turbulent flow which has a much higher loss.

 

[bubbacuse77]

GRSThegreat- the rails get a little stuff in them but I left about a 1.5 inch gap between the rails and the end plate so that it just gets pushed out. I have found more of a problem with some wood getting wedged under the wings of the wedge. It doesn't seem to bother anything so I just leave that little bit of wood in there.

JJ- Thanks for the info. Looks like I am ok using the 1/2" hose. I think I am going to use one size larger elbows however and adapt it back down as needed. If only they made 5/8" hydraulic hose. seems silly to do all this and then use three 1/2" poppet quick couplers. but since it is for such a sort space in the line it probably makes little diffrence.

 

[wdchyd]

If only they made 5/8" hydraulic hose.

They do....all the time

 

[J_J]

GRSThegreat- the rails get a little stuff in them but I left about a 1.5 inch gap between the rails and the end plate so that it just gets pushed out. I have found more of a problem with some wood getting wedged under the wings of the wedge. It doesn't seem to bother anything so I just leave that little bit of wood in there.

JJ- Thanks for the info. Looks like I am ok using the 1/2" hose. I think I am going to use one size larger elbows however and adapt it back down as needed. If only they made 5/8" hydraulic hose. seems silly to do all this and then use three 1/2" poppet quick couplers. but since it is for such a sort space in the line it probably makes little diffrence.

There is some logic about QD's, that say that QD size should be one size higher that the hose size to compensate for the reduction in flow through the QD itself.

For example, the 1/2 hose may pass 12 GPM, but the 1/2 in QD may only pass 10 GPM, so a 3/4 in QD would be call for in this example.

 

[wdchyd]

It's a result of surface friction. When you get into actual flow calculations, there are friction coefficients for carbon steel, stainless, copper, brass, etc., also values for new(clean) and used (dirty) as well as corroded. In general non-metallic materials are much rougher than metals. In addition to the friction itself,the rougher the surface, the quicker you will transition from laminar flow to turbulent flow which has a much higher loss.

Don't underestimate the friction from the crimped hose ends on hyd hose....

Have you ever tried to put a 1/8" punch through a crimped hyd hose end on #4 (1/4") .......on a Gates end your lucky if it goes in....

The friction and turbulence through the smaller dia in the fittings is greater than the hose material itself

 

[J_J]

wdchyd,

If you crimp a 1/2 in ID fitting on a hose, the fitting should still be 1/2 ID. Are you saying that the hose past the crimp is squeezed down enough to make the passage less that 1/2 in ID. If that is true, is there any way to prevent that.

I suspect, but can not verify that a 1/2 in QD is not 1/2 in throughout the QD, and is passing fluid at a lower ID rating, and that is where is the recommendation comes from to use a larger QD than hose size. The only disadvantage is cost.

 

[wdchyd]

wdchyd,

If you crimp a 1/2 in ID fitting on a hose, the fitting should still be 1/2 ID. Are you saying that the hose past the crimp is squeezed down enough to make the passage less that 1/2 in ID. If that is true, is there any way to prevent that.
.

That's exactly what I'm saying....

As I sit here at work I'm measuring a new Gates #8 hose end at the inside diameter where it slips in the hose and it's .390".....and that's before crimping

#6 hose end is .270" ID

#4 hose end is .157" ID

these measurements are BEFORE crimping.....so they'll shrink a little

the #8 (1/2") hose is measured .500" ID

No way of getting around it, it's a fact of life, that's why the gpm ratings at 20 fps of velocity is lower than the same pipe sizes.....

 

[KennyG]

We're starting to get into some technical details here. The area reduction in a fitting doesn't necessarily cause a lot of pressure drop. Pressure drop of a fitting is often calculated by determining the length of straight pipe that is equivalent in pressure drop. Fittings that cause a change of direction are much more significant than those that just cause speed increases and decreases.

I don't have my references handy, but as I recall, for small pipe, a 90 degree elbow might be equivalent to 5 feet of pipe while a sudden decrease to half the diameter and return to the original size might only be a foot or two. A smooth nozzle like diameter change causes very little energy loss.

I'm not really sure how carefully hydraulic fittings are designed, but it wouldn't surprise me if a few elbows in the system would have a lot more effect than the end fittings.

 

[wdchyd]

We're starting to get into some technical details here. The area reduction in a fitting doesn't necessarily cause a lot of pressure drop..

It may be just technical details but according to this .......http://www.cylinderservices.net/store.asp?pid=10726......there is a significant (30 to 40%) reduction in recommended flow (using 20 feet per second max) on hyd hoses

look at 1/4" size, it's almost 45% less.......surely it has more to do with hose fittings than elbows.....

I'm sure they didn't pull these numbers out of the sky and they don't mention any elbows

 

[KennyG]

Those tables are based on velocity, not pressure drop. The suction line is limited to 5 feet per second, probably to insure the flow doesn't cavitate. The pressure side is limited to 20 feet per second, to keep the flow laminar. At higher velocities, the flow may go turbulent at obstructions or fittings, resulting in very large losses.

Those tables don't appear to consider the size or configuration of the fittings. There's a note that says you should go to a larger size if you have long lines or a large number of fittings, but that doesn't provide very useful guidance.