Advice for connecting non-PT implements with a cylinder

[PTWannaHave]

Hello all,

Owning a machine such as this brand will force me to learn about hydraulics, which is all good... Please bear with me!

My 1st lesson (to receive) is about hydraulic connections to non-PT implements with a cylinder. (Connector compatibility aside/assumed; this will apply to at least two implements for me.)

The implement has 1/2" lines, with one marked for flow direction.

1. Is flow direction important? (I didn't think it was for cylinders...) If it is, how do I identify flow direction on the aux. pto lines?
2. What is the best (non-exotic/expensive) method for connecting the 1/4" aux. pto lines to the 1/2" implement lines? (I have thought of several solutions, but they are non-educated guesses on my part...)

In the fullness of time, I might want to attain the hydraulic wizardry level of SpringHollow and J_J, but that is not for this year...! (It has occured to me that the main pto with 1/2" lines is somewhat underused, and possibly could be leveraged in the future to operate cylinders as well as motors...)

Thank-you in advance,

 

[pmsmechanic]

This post is kind of hard to sort out. Several questions.

What is a non-PT implement?

Normally a pto is refereed to as a power take off which is used to power attached implements. So then what are you referring to when you ask "how do I identify flow direction on the aux. pto lines?"?

 

[ponytug]

Yes, flow can be important. Most hydraulic motors have a preferred, or exclusive, rotation. The PT PTO connectors are male/female, so there is only one way to hook them up. The Aux connectors are both male or both female and can thus be switched. I mark the Aux connectors with red and blue zip ties on both the tractor and the implement. This helps me have the implement respond in the same way every time.

You will want to choose a connector system. Either stay with the PT type (from PT, or on the open market- it is Italian, you can search the forum.), or switch everything to a flat face connector system. Either way, you want to have connectors that are self sealing and preferably have covers on them to keep dirt and grit out.

All the best,

Peter

 

[PTWannaHave]

This post is kind of hard to sort out. Several questions.

What is a non-PT implement?

Normally a pto is refereed to as a power take off which is used to power attached implements. So then what are you referring to when you ask "how do I identify flow direction on the aux. pto lines?"?

Hello PMSMechanic,

I think the post will be clear to Power-Trac owners who follow this forum...

Cheers,

 

[PTWannaHave]

Yes, flow can be important. Most hydraulic motors have a preferred, or exclusive, rotation. The PT PTO connectors are male/female, so there is only one way to hook them up.

Understood; I am talking about 'implements with a cylinder'. My implement has a cylinder with a flow direction indicated on one end of the hydraulic lines. (Might be a generic sticker that does not apply; manufacturer might use those same lines for other implements with motors...)

Cheers,

 

[J_J]

The connection of the cyl to a valve is based on what you want the cyl to do.

The orientation of the valve will cause the cyl to act differently.

If the valve is in a horizontal plane, then pushing down on the lever should logically cause the cyl to retract or go down, and just the opposite with up lever. you want to something to go up.

Now, consider the valve vertical, by pushing lever fwd, you want something to go down, and pulling back you want something to go up.

Joystick are a little different because of the side to side lever action. You want the bucket to curl up when the lever is pushed left. and the bucket to go down when you push the lever to the right. Some joystick valves also have regen which is also to the right, and affects the rod side of the cyl.

 

[PTWannaHave]

Well, Spring has sprung here last night and today...! So, I went and took another closer look at my equipment that was still packaged up. Turns out I can answer/solve #2 above:

The hydraulic lines on the implement use 3/8" hose, 1/4" fittings at cylinder, and 1/2" fittings at tractor end. So, all I need to do is remove those 1/2" fittings, install a reducer and new 1/4" fittings. Connect to aux. pto and should be good to go.

#1 remains a mystery to me. Additionally, the implement is shipped dry, so I'm wondering if I need to purge the air out of those hoses and (double-acting) cylinder before using?

Thanks,

 

[J_J]

Once the hoses are connected, cycle through the cyl operation about 5 times and the air should be purged.

 

[MossRoad]

One thing you should know about cylinders (maybe you already do, but I like to hear myself talk! )....

Typical double-acting cylinders have more force in the "extend" direction than they do in the "retract" direction. That's because there's less surface area on the side of the piston that the ram is connected to and that is the "retract" side. Less surface area = less force. So, if you have a 2" diameter cylinder the area is pii times the radius squared, or 3.14*(1*1)= 3.14sq" on the extend side. If you have a 1" rod on that 2" cylinder, you have to subtract the area of the rod from the area of the piston. The area of a 1" piston is 3.14*(.5*.5)= .79sq".

3.14sq" - .79sq" = 2.35sq" of surface area on the retract side of the piston.

This can be important when you place a cylinder on a device... where do you want the most power?

As for your directional hoses on a cylinder, as someone else mentioned, its better to hook it up the same way each time or you will constantly be re-learning which way the implement is going to move when you operate the valve.

 

[PTWannaHave]

Thanks J_J; I wasn't sure about damaging something...

Wrt #1, I seem to understand that I do not need to worry about flow direction, unlike if it was a hydraulic motor.

Thanks for the education MR; I was vaguely aware of that, but you spelled it out nicely!

Thanks again everyone!

 

[MossRoad]

Now for powering cylinders with the MAIN PTO...

Yes, you could do that. This is an open center system. That means the pump forces high pressure out, goes through the plumbing, through a valve and then back to the tank under low pressure (low pressure can still be quite high). The hydraulic pressure is always available anywhere in the system before and up to the valve. If you aren't doing any work, the fluid just goes through the valve and back to the tank. When you want to do work, some or all of the pressure is directed by the valve into one side of the cylinder and any unused fluid is directed out the valve and back to the tank.

So, lets say you want to power a big log splitter off of the MAIN PTO. You'd plumb the hose from the outlet side of the PTO, through the log splitter valve, and back to the inlet side of the MAIN PTO. However, you'd better make sure that all of the plumbing, hoses, valves and fittings are the same size or larger than the MAIN PTO plumbing or you'll create restrictions in the flow and that generates heat.... lots of heat. Because on a Power Trac, the MAIN PTO pump is ALWAYS ON! Fluid is always circulating from the tank, through the pump and back to the tank. When you flip the electric switch on the dash to turn on the MAIN PTO, that really just activates a solenoid that switches the flow from the pump to go to the fitting out on the FEL arms rather than back to the tank. All that fluid now has to go out the FEL arm, through your log splitter plumbing and back through the FEL arm and back to the tank.

You can't operate a cylinder with the MAIN PTO switch, but you can power a cylinder with the MAIN PTO, but you'll have to operate it with an additional valve.

 

[MossRoad]

Download this PDF and save it to your computer, as it moves around often and this link will go bad eventually...

Its the Army field manual for hydraulics and is GREAT READING!!!!

http://www.derijcke.com/dl/manual.pdf

They'll be a test on Friday! :laughing:

 

[PTWannaHave]

Thanks again MR; your great example above about a log splitter confirmed my understanding of how that would work.

I have a copy of that hydraulics manual produced by the US Army; have started reading it...