Gresen Hydraulics valve

[amron]

Hi all
I hope that you will be able to offer some help. came to my possession an old control valve that I would like to use. I've found that there is a "Gresen Hydraulics" logo on it. I've also found what I guess is the model of it stamped on the body of the valve but all my attempts to find some info/data regarding it on the web were in vain. if you can offer any infi regarding it - I will highly appreciate.
Thanks.

 

[teg]

Posting a photo here of the valve would help... I'm not sure if you are restricted to do so, I see this is your first post... (to cut down on spam, you have to make four more posts before you can post links and not sure if that includes photo links).

Is it a single valve? or multiple spools? (second post)

Do you know what it came out of? (3rd) This might help determine if it's open or closed center.

What do you plan to use it for? (4th) More information to see if it will work for what you want...

Now see if you can post the photo 5th

 

[amron]

Hi teg and thanx for the reply and advice.
It is a single valve.

 

[amron]

I would like to use it to control the movement of an hydraulic cylinder forward and back.

 

[Tx Jim]

amron
You need to determine if valve is open or closed center by blowing compressed air in the "in port" with spools in neutral position and determine if air comes out of "out port" or if air is blocked off.

 

[amron]

Tx Jim
I'll do just that and I'll post the result.

 

[amron]

I've attached 2 pics that I took of the valve. hope that it helps.

 

[alchemysa]

The brand was common in early Bobcats. I have 3 spools (possibly 4) in an old Bobcat 610 I am rebuilding. I have read on the skidsteer forum that the brand no longer exists but I think you've already guessed that. The seals are stock size from any hydraulics dealer.

 

[amron]

Thanx for the response.
As per Tx Jim's advice - I've connected compressed air to the inlet port (marked "P") and to the best of my knowledge it is a closed center valve since there was no outflow of air (when I've moved the operating lever, air came out of ports "A" and "B" accordingly). so, I'm afraid that it's not suitable for the purpose that I want to use it, which is to make a power unit that will drive a cylinder of a press.
since I've seen that some valves have the option to work on both modes, by placing or replacing a plug, could you tell me if it's possible on this valve as well?
btw. what is the reason to work on a closed center mode?

 

[Tx Jim]

Some hyd valves are convertible from closed center to open center & vice-verse. Can you remove plug outlined in blue and post a photo of plug & it's components? When JD announced tractors in 1960 utilizing closed-center hyd's their representatives talked about the "fuel savings" of closed center pumps not having to pump oil when not required.

 

[amron]

Tx Jim - you are amazing! I have removed the outer (the big) nut and underneath there was located a plug with an allen socket. after removing it - blowing air into the inlet yield air output from that port. now, please let me ask this: as far as I understand I have to connect this port to the tank so that the oil running during idle will flow back to the tank. when I will push or pull the operating lever, the flow should cease since the pressure is diverted to the cylinder. am I right? one more question, would you know if this valve contains a build in relief valve?
one more thing regarding the closed center mode and it is meant to save energy, but in this mode of operation the pump is constantly working against load since the center is closed, or I'm missing something?
Thanx.

 

[Tx Jim]

Ding,Ding you're the winner. Yes you're correct on routing hose from PBY fitting to tank for open center hyd system.

Closed center hyd pump has a stroke control valve that when established pressure is reached(2250 on most JD's) SC valve causes pressure to be diverted to pump crankcase which pushes pistons away from rotating pump shaft causing pump to stop pumping the pressure is also contained in the hyd supply lines. When a hyd function is activated pressure in crankcase drops allowing springs to push pump pistons against rotating shaft causing pump to commence pumping.

 

[amron]

Thanx for the explanation. if I got it right, then there is more to it that removing/replacing a plug to alter a valve from closed center mode to open center and vise versa, or the stroke control valve is built in in the valve anyhow? one more thing - I've asked earlier if you know if there is a build in pressure relief valve in this control valve? would you know if the specs/data regarding the valve can be found anywhere?

 

[npalen]

Hydraulic system, pressure and flow compensated

This, I believe, is what Tx Jim is referring to.

 

[Tx Jim]

npalen
I think what you posted is for later CC hyd systems as JD tractors with CC hyd system up to '93 can't stand hyd pressure much over 2400 psi or seals will fail. JD didn't call CC hyd I'm acquainted with "pressure & flow compensated". Some later model JD & some Fords had the CCPS & CCLS(utilized small line that sensed pressure) which is different from early JD's CC hyd's from '61-'93

 

[Tx Jim]

Thanx for the explanation. if I got it right, then there is more to it that removing/replacing a plug to alter a valve from closed center mode to open center and vise versa, or the stroke control valve is built in in the valve anyhow? one more thing - I've asked earlier if you know if there is a build in pressure relief valve in this control valve? would you know if the specs/data regarding the valve can be found anywhere?

JD ag tractors with CC system utilized very few control valves with a built in relief valves. If there was a relief valve built in it had to be adjusted at or just above stand-by pressure(2250 psi) because if relief valve opened prematurely this would cause hyd oil to heat excessively & lead to hyd pressure loss. Stroke control valve is built into frt hyd pump not any other hyd component.

 

[amron]

Hi
Thank you all for your patience and good will.

 

[Tx Jim]

You're welcome
Jim

 

[amron]

Hi
One more thing that came up (for me) is that after the modification the new PBY port will be where the plug originally was, as Tx Jim said. so, my question is what is the port next to that? it is the port next to the one that TX Jim circled in blue on the pic that I've posted. is it the original PBY port and if so, should it be plugged now?

 

[Tx Jim]

Fitting next to plug outlined in blue is the out port which should be connected to tank. In an earlier post I mis-stated that PBY on should go to tank when in reality it should be attached to next hyd function.

What hyd system or tractor are you desiring to utilize this valve on?