Hydraulic Press Ram Free Falling

[noorgatb]

Hi

We have a 250 ton hydraulic press that is used to make pots.

It has a ram cylinder and a cushion cylinder.

The Cushion cylinder works normally.

The Ram cylinder moves up and down when you press the buttons.
However, the ram cylinder free falls on its own when it is left in the up position.
It is not a slow creep. It comes down at a fair speed.

What could be the problem?
I called a technician and he said: "maybe it's the prefill valve"

We operate in a small town and we dont have access to hydraulic experts.

Any ideas where we should be looking for the problem?

Thanks in Advance.

Basheer
South Africa

 

[HPost]

It wont be the pre fill valve. Open or closed, if the press can fall under gravity, it will.

In any case, if the press does not have a fast approach function there is no need for a pre fill tank and therefore no need for a pre fill valve. Does your press have a big tank on top of the main ram?

The most likely causes are a leak in the ram seals or a leak in the valve that press sits on.

You need to tell us what type of press you have. Or post a picture.

Other questions to ask at this stage are...

1) Does the pressure struggle to make pressure on the down stroke?
2) Is the main cylinder single or double acting?

Uploading a picture will help answer many questions.

However, from your description, it is most likely to be the seal in the main cylinder.

Cheers

Adrian

 

[hydtools]

My guess is that the directional valve is leaking or not fully closing and cannot hold the piston up.
Any picture or further description would be helpful.

Ted

 

[noorgatb]

Hi

Thank you for the help.

The cylinder went in for repair recently and new seals were fitted. It worked a few times after that and then started troubling.

Please see pics.
Press Pic

Ram pic

Top of press

Top of press - Close up

Top of Cylinder. (The oil tank is on top of the press)

Regards

Basheer

 

[HPost]

It sounds like they have screwed the cylinder repair up...

I suggest you call them back and get the repair done again.

 

[lukin1977]

I dont think that is a ram cylinder.
Is it a double acting cylinder. How does it goes up?

There are some tests you can do to find out what the problem is but first you need identify the type of cylinder you have

Can you post an hydraulic diagram of the equipment?

 

[HPost]

There are no other cylinders attached to press head, so the one visible cylinder must be double acting.

It leaks!!!

Send it back!!!