basher Posted December 2, 2011 Share Posted December 2, 2011 Over the years I have managed to obtain a few hydraulic pumps . I was wondering what the difficulties were of linking the output of two together . I currently run a 10hp pump that puts out 4gpm and easily handles the 3000 psi I demand from it . I would like to link its output to the output of another pump possible a 5.5hp pump giving 3 gpm and 1500psi . this would in effect give me 7gpm to 1500 psi and 4gpm over that with the excess 3gpm being diverted back to tank through a relief valve. this would also give me the option of running one or other pump so as to not be using 15 hp constantly . I am going to be making a hydraulic rolling mill and twister and a bigger and also smaller faster press ..... So I would like a consolidated large power source capable of both fast and powerfull . I am reluctant to go to a dual stage pump as I find them so noisy my current system is quiet. any advice or pitfalls would be appreciated. All the best owen Quote Link to comment Share on other sites More sharing options...
macbruce Posted December 2, 2011 Share Posted December 2, 2011 My 10 hp mtr and pump puts out 11 gpm at 3000 psi no problem and I think yours would do the same with a bigger pump. Seems like what you're thinking of doing may be a complex answer to a simple solution. The cost of a new pump may be cheap compared to rigging the new system...... Quote Link to comment Share on other sites More sharing options...
basher Posted December 2, 2011 Author Share Posted December 2, 2011 when I chuck 11 gallon per minute and 300 psi into the hydraulic calculator I get 22hp. Quote Link to comment Share on other sites More sharing options...
macbruce Posted December 2, 2011 Share Posted December 2, 2011 Did you mean 3000 psi ? Is that 22hp output? The pump I assembled operating a hyd motor will generate 12,000+ ft lbs of torque and twist 1 1/4'' sq cold, I have no idea what hp that is..... Quote Link to comment Share on other sites More sharing options...
basher Posted December 2, 2011 Author Share Posted December 2, 2011 I was referring to the hp needed to generate 3000psi at a flow rate of 11gpm. Quote Link to comment Share on other sites More sharing options...
jimmy seale Posted December 2, 2011 Share Posted December 2, 2011 well...here we go.i don't have alot of experience with hydo. pump parallel and compounding. i have work alot with mud pumps, so principles are the same(mostly)you can stall a lesser pump with a dominent one. that would have to be solved.also the more volume equils more pressure from a given orifice.parallel will give more volume while compounding gives more pressure.if the parallel volume/speed isn't the same the pumps are fighting each other.if compounded the lead pump is more volume and the final is for pressure. now that you are confussed....if you have two identical pumps, with syncronized start and speed, you have double the volume.which you could run one at a time or two....aslong as you don't have reverse feed through the off side.remember this is doghouse engeneering,and maynot apply to the real world. good luck,stay safe, and let us know how it goes..jimmy Quote Link to comment Share on other sites More sharing options...
Drewed Posted December 2, 2011 Share Posted December 2, 2011 I work with water purification system. So my pump info may not hold to hydro, but I'll spout off anyway. in parrell, the bigger pump will chock off and stall the lessor pump, unless you hook them up with check valves, but then the bigger pump will hold the lessor pumps valve closed. Running them in serries ( out of pump one to in on pump two ) will net you nothing. More feed pressure doesn't equal more output pressure. It makes the 2nd pump pull less amps, but that is all. Quote Link to comment Share on other sites More sharing options...
Dale Russell Posted December 2, 2011 Share Posted December 2, 2011 Basher , as a certificate 4 in hyd systems design / diognostice & repair i'd say too much trouble . Firstly if i was gong to do it with the pumps you have already i'd turn the smaller pump into a low pressure high volume pump , then the larger inta a high pressure low volume pump . Then the fun really begian's , plumbing it up . You will need pressure switches , non return valves , hoses going everywhere ... Probably cheaper to sell the pumps you have & invest in a 2 stage pump ( yes i know you said you didn't like the noise ) & save yourself a lot of time /trouble & most importantly money . Have a talk to your local hyd equipment consultant , he'll likely be able to come up with a solution to your problem My 2 cents anyway , i'm sure u'll find a way around it Dale Russell Quote Link to comment Share on other sites More sharing options...
basher Posted December 4, 2011 Author Share Posted December 4, 2011 Thanks all for your coments , It would indeed seem more complicated to combine pumps that it would to use another bigger pump and bigger motor or combine motors . thanks . Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted December 4, 2011 Share Posted December 4, 2011 I don't think you would have any problem if they are both rated for the same pressure. We're talking constant displacement pumps here. There is no way one can push back against the other unless one cannot maintain the same pressure output. Flow only goes from higher pressure to lower pressure. Quote Link to comment Share on other sites More sharing options...
basher Posted December 4, 2011 Author Share Posted December 4, 2011 that is as I had previously understood it. Quote Link to comment Share on other sites More sharing options...
poleframer Posted December 4, 2011 Share Posted December 4, 2011 So, as I understand it, you want to make your own two stage system. Why couldn't you run two pumps, a large one and a smaller one off one motor, put a pressure relief on the output of the larger pump that diverts it's flow back to reservoir at say 1200 psi (or whatever you set the relief at), followed by a check valve before the lines T together, that would keep the higher pressure lower flow from the smaller pump from dumping as well. If you have a choice of pumps, and a motor that works well for you, you could arrange the best flows at the pressures you want. Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted December 4, 2011 Share Posted December 4, 2011 OK, I went back and read your OP. I see you have different pressure rated pumps. Yeah, that's a problem. Would be best to have a valve to dump the low pressure pump to tank when the system pressure is over 1500. Quote Link to comment Share on other sites More sharing options...
ptree Posted December 13, 2011 Share Posted December 13, 2011 In effect, as I read Bashers post he wants to use two pumps he has to in effect make a 2 stage pump. In my experience with a very few exceptions noisy pumps are either damaged, or have poor inlet conditions and cavitation. The inexpensive 2 stage pumps here in the U.S. the Barnes used on most log splitters are indeed somewhat noisy in many set-ups. These have a high pressure low volume section and a high volume-low pressure section. In effect, when the set point is reached, an internal valve switches and the low pressure pump is short circuited to itself to prevent the low pressure portion from making pressure. Simple, cheap, reliable, no external piping and did I mention cheap? Want to quiet a noisy pump, and make it run cooler and longer in one fell swoop? Run the pump submerged in the oil tank. You simply buy a long bell housing to ft the motor/pump combo, mount vertically and have the pump fully submerged in the tank. No suction plumbing to worry over, no suction head pressure issues and these gentlemen, are keys to reducing pump noise. The next secret, is to use a tank that is RIGID!!! A too thin home fabbed up tank will vibrate and make any system noisy. Most pumps this size need to be mounted to 1" by 2" runners welded to the top of the tank. And last set up that inexpensive 2 stage fixed displacement pump to run open center when not loaded, taking almost all of the load off the system. Properly arranged a hydraulic system should be very quiet. If not quiet, the system is singing the blues and crying for help. If that route is not acceptable, then spring more money, much more money for a separate pump un-loader and pipe it up yourself. And if not correclty plumbed and adjusted the chatter of the un-loader will be unreal. Next step up the ladder, more money is a Variable volume, pressure compensated pump. These will run to a max volume and then as the pressure builds, the pump will de-stroke the swash plate and make less flow, but high pressure in a completely variable manner. Much more sensitive to dirt, usually needs better cooling and some of these are VERY loud, mostly the big ones often seen on cement mixer trucks. Here in the US a 2 stage, 3000 PSI, 28GPM pump needing 16 Hp to run can be had for $289 each $269 if you buy 4 at a time. http://baileynet.com/index.php?dnfwd=1&page=ProductDetails&line=GPTS&baileyno=252-212 Good luck Quote Link to comment Share on other sites More sharing options...
basher Posted December 13, 2011 Author Share Posted December 13, 2011 I have purchased the valving needed to run two pumps into one system and I will see what the results are. Quote Link to comment Share on other sites More sharing options...
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