kpotter Posted October 15, 2010 Share Posted October 15, 2010 I am building a 2 cylinder 50 ton forging press I have 2 5 inch x16 inch stroke cylinders and a 7.5hp motor I was going to use the 16gpm two stage pump or would it be better to just go with a single stage pump I am doing closed die forging in it. I need more speed the press that I am using now is too slow. Quote Link to comment Share on other sites More sharing options...
arftist Posted October 15, 2010 Share Posted October 15, 2010 I am building a 2 cylinder 50 ton forging press I have 2 5 inch x16 inch stroke cylinders and a 7.5hp motor I was going to use the 16gpm two stage pump or would it be better to just go with a single stage pump I am doing closed die forging in it. I need more speed the press that I am using now is too slow. How many rpm is your motor? Most of the splitter pumps are 3600 rpm Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted October 15, 2010 Share Posted October 15, 2010 Good point arftist. Also, it's the high pressure output that will determine what GPM you can get using 7-1/2 hp. For 2500psi you want a pump rated about 5GPM @ your motor rpm. Quote Link to comment Share on other sites More sharing options...
kpotter Posted October 16, 2010 Author Share Posted October 16, 2010 It is a 3600 rpm motor, 220 3phase. I am building the frame from 8 inch 3/8 wall square tubing I want to use one of legs of this thing as the hydraulic resevoire. I think it will hold about 10 gallons I think that will be enough if not I can use both legs and that has to be plenty. Do most people use the 2 stage pumps to achive a higher pressure? Thanks for the info Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted October 16, 2010 Share Posted October 16, 2010 The two stage is the same as a one stage as far as how much pressure you get at certain HP & flow. The two stage just gives faster travel on approach and retract. Quote Link to comment Share on other sites More sharing options...
kpotter Posted October 16, 2010 Author Share Posted October 16, 2010 I have checked the specs on the haldex pumps they seem to be the most common, the 16gpm at 3600rpm is the closest to the recomended specs of 5gpm at 2500psi it has 3.5gpm for the high pressure side and 16 for the low is there any pumps that are closer to the 5 gpm or will it not make much difference. Quote Link to comment Share on other sites More sharing options...
arftist Posted October 16, 2010 Share Posted October 16, 2010 Not much difference once the die hits the work. Pressure maters then. 5gal.@ 2500psi is the max for your motor H.P. It will like having a smaller pump. Quote Link to comment Share on other sites More sharing options...
kpotter Posted October 16, 2010 Author Share Posted October 16, 2010 16gpm it is then I really appreciate the help I will post pics, Harold, a member here is doing the welding, so it wont come flying apart from my bird poop welds, the thing is heavy I am still sore from hauling the pipe into the shop. Quote Link to comment Share on other sites More sharing options...
peacock Posted October 16, 2010 Share Posted October 16, 2010 Did I miss something here? 2, 2 1/2 in. cyls at 2500 psi By my figures would not be 50 tons, more like 12.27 tons. Maybe I don,t know how to figure it correctly. Help please. 2.5x2.5=6.25x.7854=4.908 sq in.x2500psi=12,271 lb of push/2000lb per ton =6.135tonsx2cyls=12.27tons. Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted October 16, 2010 Share Posted October 16, 2010 Yes, you did miss something! I believe it's two 5" cylinders. Quote Link to comment Share on other sites More sharing options...
peacock Posted October 16, 2010 Share Posted October 16, 2010 Thanks Grant. I think I will increase the font size. Eyes and brain not what they used to be. Quote Link to comment Share on other sites More sharing options...
tala9 Posted February 4, 2011 Share Posted February 4, 2011 even at 100% efficiency it still comes up short but as a general rule of thumb you can figure about 70% efficiency in hydraulics. I have a commercial made 150 ton press designed to press forklift tires it is running at about 50% efficiency. 12" cyl at 5000 psi. Quote Link to comment Share on other sites More sharing options...
ptree Posted February 5, 2011 Share Posted February 5, 2011 Couple of things. I don't know where you live in the US, but Haldex are very premium pumps. I would suggest you give Baily Sales in Knoxville TN a look. They sell Barnes 2 stage pumps for very attractive prices. The two stage pumps are set up to move a big volume of oil at low, say 250 to 500psi to get the cylinder to where you want it. At the set point the big volume-low pressure side opens to short circuit itself drawing little horsepower, and the high pressure-low volume section can use the full horsepower to do work. Grant gave you the Hp vs flow and pressure. Good numbers. Personally if I could find it, I would go with a pressure compensated variable volume pump. Look at a Parker PAVC series. Millions made, not cheap but not premium. Set the desired pressure on the compensator, set the volume stops to not over amp the motor and now you have a "smart" pump. Throw that valve to move the cylinder and the pump strokes to make the max volume of oil, and when the work is reached the pressure starts to rise and the pump destrokes to make the desired pressure and moves only the oil needed to make the pressure even while moving. Return the cylinder and throw the valve to stop and the pump de-strokes to move a minimum of oil to make the set pressure and pulls only about 5% of the rated Hp. Another choice, if you have the Hp to move it is the pumps used on concrete mixer trucks. Same technology, tuff as nails and they move huge amounts of oil. Takes much more Hp than you mention, and these GROWL, but fairly cheap as rebuilts and again TUFF! Quote Link to comment Share on other sites More sharing options...
kpotter Posted February 19, 2011 Author Share Posted February 19, 2011 I got tired of analizing all the data I just bought the 16gpm haldex pump I figure it should work out fine for what i am doing. I hope to get this thing going by next month. I have been using my 100 ton press which is pretty slow and I was able to do what I wanted so this should be much better plus I built a better forge, having the stuff real hot seems to help more than the tonneage. I can see where the speed comes on as well. Quote Link to comment Share on other sites More sharing options...
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