Old Hydraulic Gear Pump

[NJ_Toolnut]

Hi All,

Since I've never ran a hydraulic log splitter and because I'm an absolute noob when it comes to hydraulics, please go easy on me (I learn fast)!

My neighbor gave me an old Commercial Shearing cast iron hydraulic gear pump from a dump truck. The only numbers on its data plate are 110356 and 2/86. The numbers GB1685 appear on the main casting. The inlet and outlet ports are located opposite each other. Inlet diameter appears to be 1.25" or so, outlet diameter is about 1" with 12 threads per inch. Splined shaft diameter is about 7/8", splines are ANSI 22-4/SAE B, 13 tooth, 16/32 diametrical pitch. The splined shaft sticks out from the 2-bolt mounting flange by about 1.25". Mounting bolt circle size is about 5.75". Is anyone familiar with these gear pumps or able to suggest a resource from which I can information about them? I'd like to know displacement per revolution, max RPM, direction of rotation and max pressure. Regarding a potential application, I'm exploring the possibility of using this pump to power a log splitter from my Ford 1910 Compact Tractor PTO. I have about 20 hp available at the 540 RPM PTO shaft. I know I will need a gearbox to obtain required pump RPM, but I have a milling machine and a lathe, as well as access to a welder. Since this is not a two stage hydraulic pump cycle times may be relatively slow, but on the other hand this seems like a fairly large pump with a relatively high flow rate for a splitter application. Getting it free was huge for me, since I could never justify paying the price of a commercial splitter.

Thanks in advance for your comments!

Stan

 

[jthornton]

You could screw a nipple into the suction side and put some hydraulic oil in there then turn it one turn after priming to see how much it will pump per rpm. This will give you some idea if it is worth the trouble to build one. You can get a real PTO pump from Splitez for $300. Running a normal gear pump from the tractor PTO might be more trouble and headache than a $300 PTO pump by the time you have all the couplings and gearbox etc... unless you made an adapter for the splined shaft but I'd worry about side loads on the pump if it was not set up that way in the dump truck but then you would only have 540 RPM.

John

 

[NJ_Toolnut]

You could screw a nipple into the suction side and put some hydraulic oil in there then turn it one turn after priming to see how much it will pump per rpm. This will give you some idea if it is worth the trouble to build one. You can get a real PTO pump from Splitez for $300. Running a normal gear pump from the tractor PTO might be more trouble and headache than a $300 PTO pump by the time you have all the couplings and gearbox etc... unless you made an adapter for the splined shaft but I'd worry about side loads on the pump if it was not set up that way in the dump truck but then you would only have 540 RPM.

John

Hi John,

Thanks for your response!

Nice trick you suggested to estimate pump displacement, easy and well worth trying, thanks!

You zeroed right in on my main concern, which is is going to a lot of designing, machining and fabrication effort only to find this pump cannot be used. If possible, I'd like to find out first.

I was wondering whether side (radial) load on the pump bearings could be a potential issue; thanks for confirming it might be. I never saw this pump on the dump truck, but I'd be surprised if it saw any significant radial load there. I was thinking about using an enclosed chain drive with sprockets, using maybe #40 chain and a 1:4 ratio to obtain about 2200 RPM at the pump, mainly because it does not seem likely I'd get enough flow from the pump if it was only turning at PTO RPM using a direct drive arrangement. Chain would not need to be preloaded like a belt drive, just tight enough to minimize slack. However, even with this arrangement radial load would be induced by torque as well as centrifugal force on the chain. I have no idea how tolerant the front bearing on the pump would be to radial load, but it would eventually fail if it was not designed to withstand at least some. Question is, would it fail after two cords or 100? I guess concerns about radial load could be one reason why Lovejoy couplers are included on commercial splitters and also why PTO pumps are designed to eliminate the possibility of radial loads. I should be able to come up with a design that will eliminate radial load by using a female splined coupler for the pump shaft long enough (or with additional length attached) to support the end outboard of the sprocket in a flange bearing. I will come up with a design, cost it out and see if I'm getting close to $300.

Best regards,

Stan

 

[Mac88]

Did you try contacting Commercial Shearing for specs on your pump? They have a "Contact Us" link on their site.

Commercial Shearing - Leader in Pumps, Valves, Gears and Hydraulics

 

[NJ_Toolnut]

Did you try contacting Commercial Shearing for specs on your pump? They have a "Contact Us" link on their site.

Commercial Shearing - Leader in Pumps, Valves, Gears and Hydraulics

Thanks, Mac!

I'll email them and see if I get a response, then let everyone here know if I learn anything!

Stan

 

[NJ_Toolnut]

Thanks for the link, Mac.

I've emailed Commercial Shearing and will let everyone here know whether I obtain a response, and if so, what I learn.

Stan

 

[dave_dj1]

Well look at it this way, the pump had the capability to raise a bed full of dirt, rock etc. I would bet it is big enough to run a splitter. I don't know off hand what the speed of a PTO is off from a dump truck transmission but I'm sure there are people that do know. I can't imagine it's that fast.
If you look it over closely (looks like you have but) there may be a directional arrow.

 

[Mac88]

Truck pto's come in a variety of gear ratios, and the actual output rpm is a function of engine speed.

 

[NJ_Toolnut]

Dave_dj1,

Thanks for your thoughts. I don't have access to the truck, but my neighbor told me the pump was attached to the front of the engine, not the transmission. I don't know if it ran the cylinder for the dump, or just the cylinder for the snow plow that was attached to the front of the truck. Inlet and outlet ports are sized consistent with a flow of 15-20 GPM according to my research. I looked very carefully for a direction of rotation arrow without finding one.

Mac88,

Thanks, I agree. This pump could have been designed for optimum RPM anywhere between 1/2 and 2x engine speed. The fact that it was attached to the front of the engine makes me believe it ran 1:1 with crankshaft RPM. Unless I hear otherwise from what is left of Commercial Shearing (in S. Africa), I think I am going to assume this pump can tolerate 2000 RPM and 2000 psi.

 

[Mac88]

It sounds like you're making progress. Thanks for keeping us informed.

 

[dave_dj1]

Well coming off the front of the trucks engine is a whole different deal. I think you are correct in that it had a 1-1 ratio. Now if it's for the plow's use then I would think it had ample power at 800 - 1500 rpm's.
I have a buddy that is running a pump from an old state truck on his splitter for years without issue. His is set up to run off a pto from a 70 hp diesel tractor.
He did build a chain drive gear system to up the rpm's at the pump. He has a cylinder that is about 6" bore. It has been serving him well for many years.
dave

 

[Old Doug]

I Think your pump is of off a cement truck and is a big pump. You would be better of geting something else.

 

[twinfiddles]

If you do decide to run it through a gear box, you can connect the pump (through a lovejoy coupling) to a shaft held by two pillow block bearings, to eliminate side loading the pump shaft, then put a sprocket on that shaft. Good luck with Commercial Shearing. I googled and found nothing for info on this pump.

 

[Old Doug]

I have found over the years that most companys dont keep any thing over 10years so they probably dont have information on this pump. In one way i understand why they do this but it is very unhandy for people trying to work with older stuff. Big companys are out to make money and their is not much money in helping the little guy fix something 10 years old.I was trying to rig up a pto on a truck and i had several old ones and thought if i called the place that built them they would tell me what they fit. Aftercalling one of the 3 brands that i had i got to talk to a person that had accsess to the information on what fit what. She tryed to help me calling me back 3 times but she never found proof that the company ever made any of the ptos that i had with their tags on them.

 

[Mac88]

Sometimes you just have to take a chance on finding the info you're looking for. I've had mixed results. I was having a conversation with a fellow over in the milling forum who was looking for information on an old bandmill. With a few hints he was able to come up with the information on his mill. It's always worth a try.

 

[NJ_Toolnut]

Mac88,

In terms of progress, I'm definitely learning a lot about hydraulic gear pumps thanks to everyone's feedback.

I thought emailing what is left of Commercial Shearing (they became Commercial Intertech and were then purchased by Parker) was worth the small amount of effort it took. My experience has been much like Old Doug's (companies typically don't keep info longer than ten years) but I've experienced a few delightful exceptions.

Twinfiddles,

I definitely plan to come up with a design that will eliminate radial loading on the pump shaft. I'd like a sealed case for the sprockets and chain, with bearings for the pump sprocket shaft integral to the case. The pump sprocket shaft would have the correct internal splines to fit the pump shaft, and the pump could be bolted to the side of the case. Careful alignment of the bore in the case for the pump mounting pilot with the pump sprocket shaft bearings might avoid the need to include a Lovejoy coupling, but the design also needs to include a means to tension the chain. This sealed design would keep lubrication where it belongs and keep dirt out. If designing a sealed case becomes too complicated, a open design using pillow block bearings and a Lovejoy coupling is certainly another option.

Old Doug,

My neighbor told me the pump definitely came from a dump truck. What makes you believe it came from a cement truck? I measured the diameter of the mounting pilot and it is 4". That makes the mounting size SAE B. Once I figure out the displacement, I will have a better idea regarding whether this pump can be used to make a splitter. With the displacement, I will be able to estimate flow as a function of RPM. If the pump is larger than I thought, perhaps I can run it directly from PTO RPM.

Stan

 

[Mac88]

I like the sealed case idea, but it'll require some engineering. You can tension the chain on the slack side with a teflon "rubbing block" and a through-the-case jack screw. I'm pretty sure teflon is impervious to any lube you would have in the case. You do understand that you're required to post pictures of your progress.

 

[Old Doug]

The reason I think it is off of a cement truck is the I have never saw a dump truck with a pump driven of the front of the crankshaft. Cement trucks need to run HYD all the time dumps just need it to dump. It could be a old cement truck made into a dump. We used a oversize pump on a prodject ones and it would kill the motor when lever was pulled because it tried to push 1" of hyd into a 1/2" hole. I like to make things work that i have on hand but our time is worth something.Good luck

 

[NJ_Toolnut]

Update

Hi All,

I received a response Monday morning from Commercial Shearing in S. Africa, who forwarded my message to a US distributor (Swanson Industries in Morgantown West Virginia). The Swanson contact replied almost immediately to inform me that he could determine my pump model from a couple of external casting dimension measurements. I made the measurements last night and emailed them, then received his response this morning. The pump is identical to a Parker Hannifin Model P30. The nice guy at Swanson even provided a brochure for it. Rotation is CCW, displacement is 1.97 cubic inches per revolution, maximum pressure is 2500 psi and maximum RPM is 2400. The brochure has tables showing required HP as a function of RPM at 2500 psi and flow as a function of RPM. From these tables, required HP ranges from 14 at 900 RPM to 36 at 2400 RPM, and flow ranges from 6.5 GPM at 900 RPM to 19 GPM at 2400 RPM. From the data in these two tables, I was able to graph flow vs. HP. Basically, at my max PTO HP (20) the pump will flow about 9.8 GPM, and this occurs at around 1300 pump RPM. I extrapolated flow to PTO RPM (540--the tables did not go that low) and obtained about 3.5-4.0 GPM. My conclusion is that this pump could definitely be used to run a splitter if I gear up the pump from PTO RPM to 1300 RPM to obtain reasonable cycle times, but cycle times will not be fast even then.

I would appreciate any comments you may have in view of this new information.

Stan

 

[NJ_Toolnut]

Hi All,

It gets even better: I checked the rotation direction of my PTO shaft and it is CW as viewed from the back of the tractor. This is the correct direction of rotation to mate up with the hydraulic pump through a chain drive, since the pump shaft turns CCW as viewed from the shaft end of the pump. In addition, I checked the owner's manual for my tractor and found out I have 28.5 PTO HP. I could use all of this available HP by driving the pump at about 1900 RPM, getting about 15 GPM flow at 2500 psi.

Stan