Jspool Posted March 28, 2018 Share Posted March 28, 2018 I just finished revamping my 24 ton press. Remote located the power pack (5hp 5-7 gpm), positioned the valve so the hoses are protected better, and droped the die shelf 7” so I can split billets for feather damascus. The pump and valve are of unknow age. The 5” x 8” ram is a couple years old. The press had been in service before and worked fine. Ram is still moving around 1”/sec so volume is moving. I have checked and double checked the plumbing, have trned down the relief valve, and replaced the pressure gauge, and still cannot pull more than 400-500 psi when I should be getting 2500+. I live remotely so not a cakewalk to get a hydraulic company to pay a visit without some substantial cost. Any ideas on what I can do to troubleshoot further? Could there be slippage within the valve or pump? How would I determine this? Perplexed Quote Link to comment Share on other sites More sharing options...
tdriack Posted March 29, 2018 Share Posted March 29, 2018 I like to start small - and then work up to larger component failures. If the press was working normally before your revamp - and now isn't - I have to wonder if any of your modifications are causing it? Please don't think I'm being a jerk - but are you 100% sure you re-piped it with your modifications for the same circuit? Do you have any pictures from before you could compare the piping set up to? Did you bleed the system to make sure there is no air that could be affecting the pressure in the cylinder? (it's a small system - but ....) Are your new remote hoses (or is it tubing?) too small compared to the cylinder? Can you put a pressure gauge close to the discharge of the pump to observe working pressure of the pump? Are the cylinder speed and gauge pressures consistent in both directions of valve movement? Is the relief valve separate ? or built into a control valve? From what you stated, my first impression is that the pump is working ok if you can get the ram to move as fast as you say. I'd say you have either a relief valve leaking or a control valve leaking by to the return. It could even be leak-by in the piston of the ram too. You could very slowly and very cautiously dead head parts of the hydraulic circuit to test for pressure - but that could be very dangerous if you don't know how to do it - so I can't really advocate that for you. Need more specifics about your setup and pics to really say anything more. Quote Link to comment Share on other sites More sharing options...
Jspool Posted March 29, 2018 Author Share Posted March 29, 2018 All plumbing is correct and sized right. I used to run a trawler. 100% on that. Good of you to ask though, I asked myself the same thing. Thanks for the suggestions. Well, I started last night by dead heading the cylinder hoses to eliminate any internal problemsvwith the cylinder. Same low pressure. Next, I dissassembled the relief valve thats part of the Gresen valve 6o check whether there is a piece of crud stuck under the ball orva broken spring. All looked perfect. So today I brought the valve to be bench checked at a hydraulic shop. Perhaps a blwn internal o-ring or something. Usually you can hear that whistling, but you never know. Valve checked out at 2700psi perfectly. So, that leaves the gear pump. They usually have to disintegrate to stop working, and then they make a racket. Anyway its coming off for a check. If thats not it I’ll have to find an exorcist! Quote Link to comment Share on other sites More sharing options...
Jspool Posted March 30, 2018 Author Share Posted March 30, 2018 Old Borg Warner gear pup was just plumb worn out. Ran smooth but the bronze seal plate was shot. I have a Dynamic Fluids replacement coming next week. Quote Link to comment Share on other sites More sharing options...
Jspool Posted April 7, 2018 Author Share Posted April 7, 2018 I got the new gear pump installed. Not being able to replace a discontinued Borg Warner was perplexing until I used a displacement calculator over at Surplus. Figuring out how much hydraulic performance I could get out of a 5hp motor was interesting. The general 1gpm per hp at 1500psi doesnt take into account the work load of the usage and is based upon a steady hold at that psi. In reality we only hit that psi momentarily and then the motor gets a “rest”. So with a 4kw (5hp) vfd, hevd kicked out when the relief was set at 1600. 1500 was just fine. I then installed a 5.5 kw (7hp) vfd that could handle a heavier load. I started at 1500psi and slowly upped the relief to 2200 where the vfd kicked out. I backed it doen to 2100 where its worked well. Based upon my cylinder size and speed (6.75” in 5.18 seconds) and other data here is a pic of the calculator showing hydraulic performance from a 3ph 5hp motor and a .85 cubic inch displacement gear pump. Just posting for those that may find it useful to them. Quote Link to comment Share on other sites More sharing options...
tdriack Posted April 7, 2018 Share Posted April 7, 2018 I'm glad to hear you located the problem and have it repaired! The data sheet is interesting - thanks. The part that is more interesting to me is the use of a VFD on the press and how much load it takes before it trips. I'm "very" slowly building a new press, and after some price and load calculations, I decided on a single phase 230v 7.5 hp motor instead of a VFD. It was cheaper that way in my case - but I got a good deal from a friend. Quote Link to comment Share on other sites More sharing options...
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