Thread: Workshop press build - hydraulic questions

More dumb hydraulic questions - this time about control valves and quick disconnect couplings.

Since I'll have a good hydraulic power supply I'd like to have the facility to be able to hook up a separate control valve and ram (eg on a pipe bender) using quick disconnects. Is there a standard way of setting that up?
Looking online it seems like the control valve on the press might need to have a "power beyond" port??

Regarding the quick disconnect fittings, there seems to be 2 main styles. One has the pointy bit sticking out from the male fitting, and the other has a flat face. Any recommendation on which style to use?

Lastly, is there a convention for the orientation/size of the quick disconnect fittings? I'm assuming that I'll end up with one pressure line and the other being a return to the tank. Do the male fittings go on the power source side or the remote ram side?
I assume it would be best to run a larger coupling for the return to make sure that they can't get connected ass-about.

Steve

Hi Steve, from memory (or lack there of) tractors run the female couplings as fixed while the male part is on hoses, both parts being the same size. If the operator finds that things go reverse of what it should, the couplings are swapped over. If you have the opportunity, look at small excavators and skid steer loaders for the set up on them.
I like the idea of a central pump and using different attachments, pipe bender, press etc.
Years ago, I had a machine that was built by a farmer, that was able to press bearings off and on, bend pipe, flatten the ends of pipe, punch holes cut angle and flat bar that he ran off his tractors hydraulics using one hydraulic cylinder.
In regards to the choice of coupling, I see a lot of the type that seals both ends when the coupling are separated so that very little oil is lost if any. This type are on my boss's brothers earthmoving plant.
Hyd Coupling.jpg
Kryn

For what its worth, Enerpac cylinders have female couplings and the hose end on an Enerpac pump is male.

Put 1 male and 1 female on the valve and the same for the hoses to whatever you want to hook up.
If you dont do it this way they will no doubt be hooked up the wrong way and things will operate the wrong way when you pull the lever. This might not be too much of a drama for what you are doing but when I see a machine fitted with 2 females or 2 males on the valve I immediately think "who was the moron who put this together" and what else has he stuffed up?

If you're starting from scratch with no existing gear, I'd go with the flat-faced connectors (provided they're not significantly more expensive). As suggested, I'd arrange the male-female connections to you can only connect it the right way, then you can use the same size hose for everything (which you size based on flow).

On pretty much all the mobile equipment i have worked on the power source has female and the equipment has male ( excluding enerpac type equipment but that's a bit of a different ball game). I can also guarantee they will weep a bit of oil.

Thanks guys. The one male, one female on each side makes sense to me. About as simple and idiot proof as I can make it.
Having both the same only makes sense to my brain if they are lines to a ram, where (other than direction) they have the same function.

I'm thinking I'll put the quick disconnects on the power pack side of the press ram control valve, and a pressure relief valve for safety on the output side of the pump in case it ever got turned on without anything connected.
Then its just a case of connecting either the press or something else remote that has its own control valve. Keeps the control valves simple and makes sure the control is located where its going to be used and not tempting me to hook up a ram and control it with the valve on the press frame.

I got lucky and scored a 3hp 3-phase power pack on ebay for just over $100. Complete with tank, accumulator (which I'll remove), guages and some solenoid control valves (which I'll also remove). The tank is just the right width to fit what I had in mind for the front-back dimension on the press frame. I could run it straight off my phase converter as-is, but will probably run it off a VFD so I can just plug into the 15A outlet that is near where the press will be located.

Slowly getting all the bits together....

Steve

Good to see you are making some progress.
With the couple units, as others have suggested putting one male/female on each is a good move. Saves a lot of confusion down the track.

One thing I`d suggest is to make sure they have a lock system so they cannot accidently come apart.

DSC07789.jpg

The two sets (high pressure) on the right the outer ring screws on to lock the fittings together. The centre and far left sets have a ring that turns about 45deg that stops them from disconnecting. The second from the left (not my preferred setup) has no locking system. I have seen these come apart for various reasons.

With the pump I like a complete (self-contained so to speak) setup.

DSC07751.jpg

I run a manual and a pneumatic control valve. The pneumatic is good as I don`t have to be standing right next to the pump to operate it and I can operate it with hand or foot controls. I find the foot control is very handy for my rollers were two hands on the job is a good thing.
Both of these valves are open center . That way the oil is being returned to tank without going through a pressure relief. Saves on heat build up in the oil and no sustained back pressure on the pump.
Each valve has its own flow control and pressure relief setup. The pressure relief on the pump is set to 5000psi and is never touched. If I want to reduce pressure I use the ones on the control valves. I like the safety backup. I have come across a few pumps failed because people have played with the main relief valve. Pumps break when there is no where for the oil to go.

Press is nothing special, made from bits I had at the time.

DSC07785.jpg

Hand pump and pneumatic foot pump connected via a t piece to a single acting spring return 50 tonne ram. 95mm bore 330mm stroke. Its 10,000 psi equipment but the press itself is not strong enough for 50 tonne so I have limited it to 5000 psi max to give 25 tonne.

Being single acting its slow, painfully slow. I have the bits to turn it into a double acting but I use the press so little it just seems to be pushed back on my to do list.

DSC06878 me.jpg

Tony

Thanks Tony - great info.

I was looking into the flat face couplings yesterday, and the locking aspect was one advantage that came up.
Looks like they are about twice the price of the poppet style ones, but not like I need to buy a dozen of them.

I've thought about having the power unit completely separate, but I'm getting a bit pushed for floor space hence planning on mounting it on the top of the press.
Its pretty much a self contained unit at present anyway - albeit with a lot more gubbins on it than I need - so probably a good idea to keep my options open and mount it so it could be removed easily and thrown on some wheels down the track if I want.

I like your pneumatic control valve. Does it give you variable rate control or just on/off?
I don't know anything about them - do they need a compressed air source, or does it just use the displacement from eg a piston on the foot pedal to move the valve?

Steve

This is the power pack I picked up. Bonus that it had a hand drawn circuit diagram stashed inside the electrical box.
Its got me a bit confused though, as all the control valves have 240v coils, but there doesn't seem to be any 240v input to the electrical box. Only the 3 phase input for the motor, which appears to go straight through to the motor itself. No empty cable glands where there might have been a 240v feed pulled out etc.
I haven't looked any deeper at the moment - just had a quick visual look over it.








Steve

$100.00 for that!!! I hate you. (not really I am just full of envy). That`s one serious piece of kit.

Solenoid (electric) controlled valves with manual directional adjustable flow on each line. Main pressure relief and pressure relief on each valve. Nice.
The 240v to control will have been picked off the 415v somewhere.
Does not appear to be a control box.

These solenoid valves like pneumatic ones will be on or off but you do have flow control on that system.

This could be setup a number of ways. 240v on/off switches or bypass the lot and fit a manual valve. The possibilities are endless.

Tony

I see in the schematic the coils on the valves might be 110v.

Tony

PS I still hate you.

LOL - If it makes you feel any better it’s very unusual for me to get a bargain. I’m usually the bloke that buys something full price and gets it freighted from the other side of the planet then the next day one is available for cheap just down the street and the seller is happy to drop it off !!

By the sound of it I need to get my head around what the different components are in what I’ve got there. My initial thought was the strip it back to just a basic pump and relief valve but maybe that’s not the best idea.

Steve

Hi Steve, Guys,

There is a lot of spike suppression capacitors in there ! Makes me wonder why.

Originally Posted by BaronJ

Hi Steve, Guys,

There is a lot of spike suppression capacitors in there ! Makes me wonder why.

I assumed it was for the control valve coils....??

Edit: and they are rated at 240v AC/DC:







Steve