quick coupler flow question

[backintheday]

My snow blower can operate between 11 and 25 GPM and uses 1/2" QD which from what I've seen max out at 12GPM. It it worth it to install 3/4" QD on 1/2" hose to allow more flow or is the 1/2 hose restricting the flow as well. I'm in the process of gathering parts for a PTO power pack and I want to build it right the first time, any advice is appreciated, thanks.

 

[J_J]

A good practice is to install one size higher QD over the hose size.

 

[BAP]

The other thing to make sure is that the QD you get are high flow rated. Different style QD's have different flow ratings. Flat face are usually higher rated than the pin or ball type.

 

[Discount Hydraulic Hose]

My snow blower can operate between 11 and 25 GPM and uses 1/2" QD which from what I've seen max out at 12GPM. It it worth it to install 3/4" QD on 1/2" hose to allow more flow or is the 1/2 hose restricting the flow as well. I'm in the process of gathering parts for a PTO power pack and I want to build it right the first time, any advice is appreciated, thanks.

These 5/8" Flushface Couplers are rated for up to 27 GPM
Set of 5/8" ISO 16028 Couplers with 3/4" NPTF Female

Of course, changing the couplers to accommodate your snowplow may complicate things for the other attachments you use. You may need to change the couplers on all of your other attachments as well. Flushface couplers cost a good deal more than the standard agricultural couplers, so that is a consideration as well.

 

[J_J]

These 5/8" Flushface Couplers are rated for up to 27 GPM
Set of 5/8" ISO 16028 Couplers with 3/4" NPTF Female

Of course, changing the couplers to accommodate your snowplow may complicate things for the other attachments you use. You may need to change the couplers on all of your other attachments as well. Flushface couplers cost a good deal more than the standard agricultural couplers, so that is a consideration as well.

What chart did you use to obtain that GPM

Those figures are hard to believe.

What is your reference?

Hose Size Selection Nomograph - RYCO

 

[IceStationZebra]

What chart did you use to obtain that GPM

Those figures are hard to believe.

What is your reference?

Hose Size Selection Nomograph - RYCO

I internally blew apart a typically Ag type coupler many years ago. As I dug into the vendor's catalog (maybe Parker?) I was surprised by the number of difference, but compatible, couplings they made. All varied by quality, cost and flow. Also, it's been many years since I looked into this, but I don't remember there being any standard associated with the quoted flow value so the vendor could pick any pressure drop they wanted.

As far as the original question goes, any reduction in pressure drop is a good thing within reason. You will reduce the heat generated and fuel burned. The actual savings will vary considerably depending on the conditions.

ISZ

 

[IceStationZebra]

The Parker 3800 catalog has the pressure drop curves. 25gpm was way off the chart for 1/2" couplings, but if one extends the curves you are looking at 50-100psi pressure drop with warm oil. (assuming it doesn't cavitate, which is a definite possibility.) A 3/4" coupling, depending on the design, is 7-20psi pressure drop.

worst case: 25gpm x 100psi = 1.5hp
best case: 25gpm x 10psi = 0.15hp

assume 0.5 gallons/hr savings, or ~$2/hr

ISZ

 

[Cord]

I can't figure this out. I agree that 1/2" couplers are rated for 12gpm, but my skid steer, from the factory, pushes 36gpm through them. My new pump has been flow tested at 46gpm. Same couplers are on the high flow side as the standard flow. I have a hunch that the rated gpm is base upon pressure loss and when dealing with 3,000 psi you can afford to lose a few psi at full flow. Generally when the pressure starts to rise the flow drops off anyways.

 

[J_J]

http://www.eaton.com/ecm/groups/public/@pub/@eaton/@hyd/documents/content/pct_472512.pdf

Nowhere on this PDF did I see the flow rates some of you stated.

Hose Size Selection Nomograph - RYCO

I still don't believe the QD will pass the same volume as the hose size it is attached to.

One should use one size larger QD over the hose size.

 

[Discount Hydraulic Hose]

What chart did you use to obtain that GPM

Those figures are hard to believe.

What is your reference?

Hose Size Selection Nomograph - RYCO

I got those numbers from our own catalog, which appears to be incorrect now. I checked the 2014 Dixon Quick Coupler Catalog, and they show 5/8" ISO 16028 couplers at 21 GPM maximum flow rate.

 

[CJONE]

Experience is the best teacher when it comes to quick couplers. There is so many different "standards" that the MFG's use it's pathetic. For good flow per hose size I stick with the ISO B quick couplers [poppet style] and for my high pressure high flow units, I use Stucchi VEP flat face series. To give a example a VEP 1/2" would give you a total pressure loss of 90psi for a circuit at 25gpm. 45psi per coupler. I would not use 1/2" hose for 25gpm. 3/4" pressure lines are a better choice. Esp in the winter. CJ

 

[IceStationZebra]

I can't figure this out. I agree that 1/2" couplers are rated for 12gpm, but my skid steer, from the factory, pushes 36gpm through them. My new pump has been flow tested at 46gpm. Same couplers are on the high flow side as the standard flow. I have a hunch that the rated gpm is base upon pressure loss and when dealing with 3,000 psi you can afford to lose a few psi at full flow. Generally when the pressure starts to rise the flow drops off anyways.

Cord, understand that you can always push more through than rated. In simple terms the quick couplers are just a restriction, so it all comes down to how much pressure drop you can live with. And like several of us have noted, there is a wide range for a given size coupler - even within the same companies products. It is all a compromise between cost, durability, pressure drop, ease of coupling and seal integrity. ISZ

 

[MHarryE]

And the -12 hose size results in 44 feet per second velocity at 27 gpm which is triple the recommended maximum.

 

[CJONE]

And the -12 hose size results in 44 feet per second velocity at 27 gpm which is triple the recommended maximum.

???? are you sure ? I am showing about 26. Well within spec for pressure lines. CJ