Pump question

[ParkerFly]

I have a 12 gpm hydraulic pump out of a combine that has two pressure ports on it. One flows 8 gpm out of it to supply the hydrostat and the other port flows 4 gpm to supply the rest of the machine. It's not going to be used in a combine anymore and I'm wondering if the small port could be capped, would all 12 gpm go out of the large port? I need a 12 gpm pump and this one was free, but I need all the flow out of one port. Can anyone help? Thanks,

Justin

 

[Egon]

The pump produces 12 gpm so it may be ok as long as the 8 gpm line size will handle the extra 4gpm.

 

[ParkerFly]

That's what I was thinking too but wanted to make sure. The pump has 1/2" lines on it now which from what I understand will flow up to around 15-16 gpm safely.
Another question about this pump, is it safe at all to go to a smaller pulley and slightly overdrive it? I only thought of this because it has a massive pulley on it now. I wouldn't want more than 15-16 gpm because I can't afford to replace the miles of hydraulic line with larger ones. Thanks again,

Justin

 

[ThomasH]

As long as it is a simplex pump, that is one with only one physical pump section in the case, it will work fine by capping a port. So, have you taken the cover off the pump and looked? Does the pump have stacked sections like a typical duplex or triplex pump?

Tom

 

[AKKAMAAN]

this is most likely a double pump, two pumps in one housing...capping one outlet will make you VERY UNHAPPY..
That port that you do not want to use, then must be py passed to tank...

 

[ParkerFly]

I haven't taken the pump apart and don't have it next to me right now. Here are some links pictures of the pump still on the piece of equipment if it helps any.

http://i231.photobucket.com/albums/ee45/jbcollier22/lunapic_128743391831131_1.jpg

http://i231.photobucket.com/albums/ee45/jbcollier22/IMG00004-20100520-1540.jpg

http://i231.photobucket.com/albums/ee45/jbcollier22/IMG00002-20100520-1540.jpg

 

[AKKAMAAN]

I haven't taken the pump apart and don't have it next to me right now. Here are some links pictures of the pump still on the piece of equipment if it helps any.



it is un unfamiliar pump to me...you have to test if it build pressure independently on the two ports

 

[wdchyd]

Looks like a single sectioned Webster Gear pump to me....it may have a priority bypass built in to the rear cover that does not show on the pics, but looks like a single gear section.

Does it have three ports on the rear cover or two?

 

[glastron23]

am i missing something???/ i only see 2 hoses, the top should be the pressure line and the bottom should be the suction???? it looks like an old Gresen pump.. Jim

 

[Iplayfarmer]

Test it...

Make sure you have a fluid supply to the inlet port and cap the one outlet. Try to turn the pump by hand. If you can't turn the pump (or it's very hard) you can't cap that port. If it turns just fine and fluid comes out the other port, you'll be fine.

 

[Egon]

The pump produces 12 gpm so it may be ok as long as the 8 gpm line size will handle the extra 4gpm

Uh-oh; some bad advice here without knowing exactly what type of pump!:ashamed:

 

[gpflepsen]

You do not want to cap an outlet. Case go break! You could plumb the lesser outlet to tank, through a cooler/filter or secondary circuit of some sort. Depending on the supply line used, you may be able to plumb the lesser output to the suction side and be fine. Just watch the heat generated.

Is this the pump?

 

[ParkerFly]

That looks like the pump in that picture. I'd have to look at ours, but it definitely has 3 lines (2 pressure, one return), I just can't remember where they all are on the pump.
What about using a T to tie both lines in together? Instead of capping one, feed both into one line? I probably should have thought of that earlier, but it seems like that would be simple to do.

Justin

 

[gpflepsen]

Well, it may work to combine the outlets. As was said earlier, there is probably some type of flow divider. I'll let others comment on the wisdom of this approach.

Check this exploded view at http://ep.yimg.com/ca/I/yhst-85473676144382_2081_9846328, which may be the pump in question.

 

[Farmerford]

The parts between caps #22 and #23 on gflepsen's attachment are probably a flow divider. Because it has springs on each end of the spool (between the caps) it is probably a proportional flow divider rather than a priority flow divider. That is, whatever fluid exits the pump will be divided 1/3 to one port and 2/3 to the other port. Depending on the design, if you block one port the spool may shift to send all the fluid to that port in order to try to keep the proper balance between the ports. Of course, with a blocked port that will not happen and pressure will build up in the pump; there appears to be a relief valve in the pump body to avoid damage.

So, it should probably work fine to connect both out ports to a single line, which will combine both flows. But if it were me, I would just remove the proportional flow divider parts: everything between the caps (except the sealing o-rings under the caps, of course). There is bound to be some pressure loss in the fluid as it winds its way through the flow divider, and you might as well eliminate that if you can.