Pumps pumps pumps

[dodge85rc]

On the home made tractor I am building I am going to be using the hydraulics to run some "pto" attachments. I have a clutch pump that is rated at about 20 gpm, which is sufficient to run the attachments and should have enough left over to run the steering and a few hydraulic cylinder valves occasionally. What I am starting to think may be the way to go, instead of trying to split the flow and divvy things up, would I be better off to just run a small pump(I have several that are in the 3-5 gpm range) to dedicate to my hydraulic steering and hydraulic valves and keep the clutch pump for the PTO functions and just wire it up to a toggle switch to turn it on as needed. My next question would be, in that scenario would I need 2 suction lines or could I just use one and T off of it or install a priority divider valve?

 

[J_J]

I believe I would use two suction lines. A flow divider for such things as the power steering would be a good thing.

 

[Egon]

What would be the difference between two suction lines and a properly sized single line with a T and corresponding properly sized lines??

Go with the smaller dedicated pump for steering.

 

[AKKAMAAN]

What would be the difference between two suction lines and a properly sized single line with a T and corresponding properly sized lines??

Go with the smaller dedicated pump for steering.

Agree! No difference!!!

 

[J_J]

Agree! No difference!!!

I think you are assuming that the suction port on the tank is way larger than it is. If the suction port on the reservoir is sized for the current pump, say, 1 in, and you are adding another equal size or larger pump, what are you going to do, use both pumps to draw from that same 1 in port.

Probably have to get a new reservoir, or cut and weld in a new port.

 

[dodge85rc]

So I'm lost does it matter if there are 2 suction lines or will a T suffice? The suction line port on the tank is 1 inch.

 

[J_J]

You will have to know the total GPM's of both pumps in order to figure out if the current suction port is adequate for the volume of fluid. I am thinking that you need two ports.

 

[AKKAMAAN]

So I'm lost does it matter if there are 2 suction lines or will a T suffice? The suction line port on the tank is 1 inch.

well....1" is way to small for 20gpm+.....you need at least 1 3/4" for 23gpm and the recommended 4ft per second fluid velocity....then more, 2", if you add mor flow (up to 31gpm)

Have a [URL="http://akkamaan.com/hydraulic/excelsizingnomogram.xlsx"]xlsx-calculator here for hose sizing[/URL]if someone have Excel 97, and want to play with it....on your own risk of course.....LOL

 

[J_J]

http://kuriyama.thomasnet.com/Asset/H SizingNomogram.pdf


Hydraulic Hose Sizing




* Flow speeds at the lower end of the ranges should be used when designing for a continuous duty system. The inside diameter of the hoses should be chosen such that the needed flow rates can be supplied at fluid speeds within the acceptable ranges listed above.

* The following equation can be used to relate flow desired flow rate
to hose diameter:

Where Q is fluid flow rate in gallons per minute, D is the inside diameter of the hose in inches and V is fluid speed in feet per second, 20 to 25

Q = 2.45 X D2 X V

 

[dodge85rc]

http://kuriyama.thomasnet.com/Asset/H SizingNomogram.pdf


Hydraulic Hose Sizing




* Flow speeds at the lower end of the ranges should be used when designing for a continuous duty system. The inside diameter of the hoses should be chosen such that the needed flow rates can be supplied at fluid speeds within the acceptable ranges listed above.

* The following equation can be used to relate flow desired flow rate
to hose diameter:

Where Q is fluid flow rate in gallons per minute, D is the inside diameter of the hose in inches and V is fluid speed in feet per second, 20 to 25

Q = 2.45 X D2 X V

According to that, with a 20 gpm pump, 1 inch suction line I am right at the lowest mark for velocity for suction lines, if I drew my line straight.