Thread: single or double acting cylinder??

You don't need a hydraulic return so long as you have a couple of biggish extension springs hooked up. 2 trampoline springs return my little 5 ton home-made press quite snappily...

2. or you could use air pressure to return the ram.

Originally Posted by bee utey

You don't need a hydraulic return so long as you have a couple of biggish extension springs hooked up. 2 trampoline springs return my little 5 ton home-made press quite snappily...

2. or you could use air pressure to return the ram.

I dont want to use the external return springs as this limits the versatility of the ram...

how would I use air on a single acting cylinder?

sounds like you would need an airbag

Go the double acting cylinder

You don't need a different pump, he's just trying to make sales. Just the same pump with a 3way L port ball valve or two. You don't say where you are but if in Syd I can help set up.

There's a lot cheaper ways to go than enerpac too. Speak to Cross Hyds in Wetherill Park Syd.

Im on the Gold Coast. Looking at Enerpac, Simplex and SPX Power Team becuase 1, i already have a air/hyd pump and 10t cylinder on my JD model 4 bender (SPX Power Team), and 2, these are the most popular brands to be had on ebay.com (usa)

going double acting is easy, just have to sell my car to buy the cylinder...going from single to double, just buying the pump and cylinder in the same brand, same size cylinder etc etc is atleast 50-70% more...just so you know im looking at brand new single acting 50t cylinders for $1000

regarding the pumps, why do all the brands specifiy different pumps for single and double...I notice the Cylinders have 2 lines instead of one....i to return, and there are valves built into the pumps also????

what percentage over cylinder oil capacity is required in the pump?

Enerpac specs a "different" pump which is the same pump with different valves attached.

You just need a pressure source, a way of sending the pressure (selectively) to either end of the cylinder and at the same time diverting the opposite end of the cylinder back to tank.

Oil capacity is a variable. It's not going to be working to hard and will not be around any heat sources (unlike PTO driven pumps & other equipment mounted on trucks) so you don't need to worry about using the tank to disperse heat. Plenty of filtration is a must. Suction filter either in tank or inline before the pump, pressure filter after pump and return filter post all other devices (again either in tank or inline). Suction and return filters (inline) can be spin on, just use a remote filter head you can buy for a car (although these won't have a bypass built in) and a matching filter. These will filter at approx 125um. pressure filter should be around 10-20um.

They seem like expensive cylinders. Look for "ag" cylinders, they are made for, well, agricultural purposes and made to a price, usually not rebuild-able but for your purposes should be fine. They are available in D/acting (used to lower/raise tractor attachments).

the combination double acting Ram and hand pump cylinders are usually sold as a unit as the head of the pump cylinder has a 4port 2 position valve built into it. This controls the direction of flow of the oil from the pump to one side of the RAM and the other side of the ram to the tank.

because of the intergral valve and tank setup of the single acting cylinders pump you cant just put that pump onto the double acting cylinder. You can do it but you have to mod the tank and fit a secondary valve that does the return to tank function.

you can get a single acting pump that has a reversing valve in it that has a "suction" function that reverses the flow of the pump and pulls the oil from the cylinder and puts it into the tank. They work resonably well untill the seal on the RAM starts to weep and it then sucks a little air into the cylinder and you loose the prime on the pump.

IF it was me and the double acting ram was the primary requirement and the minimum cost was the aim ID

fit AG ram or a double acting ram from something like a grader. plumb in a 2port 2 position spool valve that swaps the A+B ports across the T and P ports. Fit a powersteering pump thats got a remote resivior from something like say a D2 and run it off of a small 12v motor or fit up a hand crank.

without the Ram depending on your scrounging skill should cost you sub $200

You could use a 4 port, x ported manual valve to do the cross over but that's getting pricey. Look up on ebay CETOP 3valve with 2/2 crossover function

Bazinga



Hydraulic solenoid valve segment SWH 12 volt (eBay item 250752994643 end time 13-Jan-11 19:37:18 AEDST) : Industrial

Is not perfect (has open centres) but will do,it's certainly the right price.I saw it listed previously and has been put back on, you should get it for the $60- they are asking. From anywhere else you'd be talking $200+. Now find a cetop 3 subplate (pref side ported, easier to plumb). If you need somewhere to get one let me know and I can put you onto someone in Bris to help out.