Hydraulic Question..

[12vman]

Could a hydraulic cylinder be used as a piston pump or am I just spinnin' my wheels again..?

Thanks in advance..
~Don

[Windy in Kansas]

Originally Posted by 12vman

Could a hydraulic cylinder be used as a piston pump or am I just spinnin' my wheels again..?

Thanks in advance..
~Don

Probably, but you would have to work out a valve train system to allow fluid to enter and exit. Would you be using a double acting cylinder or a single acting?

Just curious, what length of cylinder stroke would you be thinking of using?

Not really much different than a water well pump cylinder if you think about it.

[12vman]

Double action. I'm wanting to pressurize hydraulic fluid to operate a hydraulic motor. A cylinder sure would give me plenty of flow.. LOL

I'm brainstormin' again..
~Don

[michiganfarmer]

A cylinder is going to have a lot of resistance. It will take a lot of arm strength.

I think it will work, but I dontknow if you are going to want to pump it by hand

[Windy in Kansas]

Well--knowing the inefficiencies of hydraulics, motors, etc. I doubt you would have a viable product UNLESS you are driving the cylinder pump via free energy, i.e. water wheel, mill, etc.

I checked into using hydrostatics for a small tractor and was told by the hydraulic company that the initial loss was 20%, meaning my 20 horsepower engine driving a pump would yield only 16 hp for driving the unit. Still a great way to control speed however even with a loss.

[Ross]

You could add a hydraulic accumulator to get smooth running motors. You'd need a heck of a power source to pump with a long stroke piston like that so keeping it short would help like a small piston hydraulic pump.

[rambler]

Durability comes to mind as well. A cylinder running that fast & constant back & forth is going to build up some kind of heat.

--->Paul

[12vman]

Like I said.. I'm brainstormin' again.. LOL I'm revisiting a drawing that I made a few years back..

Any of you folks know anything about the hydraulic pumps that operate from the PTO of a tractor? I know the input r.p.m. is around 540 (I believe) but what can be operated from the pump? (as for h.p.)

Thanks again..
~Don

[rambler]

They will come in different sizes, depending on what you want. Common are about 7-10 gallons or 20 gallons per minute output. Other sizes can be had. Big hyd cost big $$$.

Common pto speed is 540 max. Bigger tractors over 65 hp will have 1000 rpm pto. Engine speed pumps would run at about 2000 rpm.

Looking through a farm scrap yard, combines tend to have self-contained hyd pumps that run off a belt from the engine........ If you are looking for ideas........

Would open center or closed center better fit your needs? Open is constant flow, with variable pressure; closed center is constant pressure, with variable flow.

--->Paul

[agmantoo]

12Vman,
I have a log splitter that I made that has its own independent oil reservoir. I loan this to some neighbors and I did not want their tractors hydraulic oil mixed with my tractors hydraulic oil. I made a short PTO shaft that connects the gear pump to the tractor PTO. The log splitter is a 3 point attach so it can be raised for transporting and sits on the ground for using. I use a Commercial Shearing pump salvaged from a large industrial air compressor. The pump delivers about 12 gpm at fast idle of the tractor/pto. I can vary the engine speed on the tractor to make the splitter match the speed that I want the splitter cylinder to travel. Here is a source of some good info http://www.baumhydraulics.com/pages.php?pageid=4

[Ross]

I had looked at hydraulic powered equipment with a mind to front mount a snow blower (7 foot) and while the details are fuzzy (never did the project) I remember that motors are measured in inch pounds of torque and to equate something big enough to just turn over a snowblower it was somethng like 35,000 inch pounds. In fast terms a pump and motor system from a hydo swing haybine would have powered the blower well, one for a log splitter no more than turning it over with no load.

[Beeman]

Prince makes hydraulic pumps that slide on your tractor PTO shaft.

[Blu3duk]

Surplus Center has some great items and always has had since ive been getting their catalog the past 20 years or more.... they had at one time a awesome set of books on hydraulics that would answer any questions but was outside my interests at the time [shouuld never pass a deal up on books to learn from] but they still have a few good books under their accessory category under hydraulics.... I did have them toss in the buck and half fluid power data booklet on an order one time and it has great information if you can apply the numbers to your project [not sure where it is laying around right now but i seen it recently in a search for another book in my boxes of books in the shop/laboratory]

They also have several sizes of PTO pump too... did I mention I kind of enjoy their catalog about as much as I do Lindsay technical books which also has some hydraulic information books once in awhile too.

William

[Beeman]

http://www.northerntool.com/webapp/w...9700_200329700

Here's a Prince pump that will work.

[DaleK]

Newer White corn planters have pumps on the PTO as well, to run the blower for the air. Wouldn't think there's a lot of power there but there's enough that they need their own cooler to keep the oil cool. Some of the newer forage wagons are run hydraulically off a PTO pump as well, particularly receiver wagons. Takes lots of power to run off 10-15 tons of silage.

[rambler]

That's right Dale, Case (Case-IH) planters have had pto pumps for years on their air corn planters, can sometimes buy a whole 400 series planter for $300 or less. They came with 540 or 1000 version pumps. Pretty good output. Suprlus Center sells that type new, I bleieve.

--->Paul

[12vman]

WOW! Thanks Everyone! I've got a lot to learn.. LOL

Beeman, that's the type I was thinking of. I believe that type would work the best in my situation.. (or thought)

OK.. Here's my thought.. Be it off of the wall or not..

A friend of mine has a creek that runs across (through) his property. He owns both banks. He's building a pond and is in the process of building a levy. The creek is about 3-4 foot wide with quite a flow. He's been monitoring it now for a couple of years and the flow stays pretty constant except when it rains. It rises somewhat. (to be expected, overflow bypass considered)

We are looking into building a water wheel at the over flow point of the levy. Possibly an under shot set up. (due to the situation of the property) Dividing the over flow into two sections so it could drive two wheels instead of just one. The two wheels are to be built using a differental from an automobile for the shaft or pivit point. (welding the gears to make is posi-traction) Doing this will give us an output to a drive shaft so to make the connection to them easy and to provide a little gearing..

The size (circumference) of the water wheels could be unlimited being the water would be going under them instead of over them. A platform could be built using telephone poles to mount the differental above ground level with some bracings to keep them stable..

Now we have two wheels turning the differental, the output is a drive shaft with a wee bit of gearing. Now the issue is to get the R.P.M.'s up to a usable speed.. (The reason/intrest of the P.T.O. pump.. Low R.P.M.'s, Good flow)

My thought was using a standard transmission "Backwards".. Input into the tailshaft via the drive shaft from the wheel set up, and connecting the P.T.O. hydraulic pump to the spline shaft of the transmission. (With an adaptor to fit the pump) A saddle bearing to support the spline shaft like the pilot bushing does in the vehicle originally..

Now we have low R.P.M. input with lots of torque with an easy means to adjust the input R.P.M. to the pump. I believe a transmission could handle this set up just for the input torque needed to operate the pump. I'm sure the pump doesn't have to operate at exactly the required speed. Possibly a little above or below wouldn't hurt anything but you get the idea..

The product of all of this is to operate a hydraulic motor somewhere in the 20 h.p. range to operate a generator. The hydraulic motor R.P.M.'s could be controlled to the proper speed to keep the generator close to 60 cycles I believe, IF there's enough flow/pressure from the pump.. (Maybe some R.P.M. adjustment needed here also according to the capabilities of the hydraulic motor) Another unknown..

I see a little math coming into play. My head hurts already! Gear ratios, ft. lbs. of leverage, friction losses and all of that other good stuff..

So.. Am I nuts or does it sound doable? I know there's alot of variables involved but that creek sure does flow nice and never underestimate the power of leverage..
~Don
(Patent Pending.. LOL)

[Ross]

If memory serves the largest over shot wheel puts out about 100 hp....... and it's pretty darned big. I wouldn't say powering a hydraulic motor is efficient. I can power a PTO 9 foot haybine with 45 hp and unless it has to climb some serious hills with heavy hay it'd do the job. My Hesston 1010 hydroswing cut 9 foot, I don't think anything less than a 60 hp tractor would power it, but it could make 80hp labour.
I think 20 hp is too optimistic........... but 1-5hp and useful waste heat might be attainable.

[12vman]

I figured the hydraulic motor because the R.P.M.'s could be controlled. Another thought was to drive 2-3 or several high output alternators from the spline shaft. I know I could get enough R.P.M.'s and the speed wouldn't be as crutial BUT it would require more torque to get the needed R.P.M.'s for the alternators. It's my thought to keep the needed R.P.M.'s as low as possible to get more torque from the wheels..
~Don

[rambler]

I tend to pick apart ideas, so bear with me. I'm not a negative person, & I like your experiment & creativity. I simply find it easy to list out weak points in a plan. Don't know why.

I should think 1 larger (wider) wheel would be more efficient than 2 side by side. You would have less bearings & structure. Less of those is always more efficient. The rear end is handy, but may not be the best for efficiency.

Hydraulic is _terribly_ inefficient. I see that as a killer for your project. You will produce a lot of heat in the oil, which is wasted energy. Couple the generator to the output shaft. I understand you need to regulate speed, but hydroulics is going to end up wasting 1/3 of your power before you even get to the generator.

Those are the design parts I would focus on improving. Doesn't mean I don't like your project, or your exact plan won't work as is! Just thoughts....

--->Paul