INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

What valve brand do you recommend ?????

What valve brand do you recommend ?????

(OP)
So I ordered my "Brand Hydraulics" flow valve.

I now need to order three more hydraulic valves ( plus a couple of check valve and such ). They need to be spool type solenoid valves ( two port, two position ... blocked and flow ), 24 VDC ... two N.O and one N.C. I am going to flow about 15 GPM max.

I went to the "Hydraulic Force" web site .... just because I had used them a few years back ... and looked up a cartridge valve with a manifold ( I thought I bought them as one last time but it looks like I must buy the two parts separately ).

I was very surprised to read the "internal leak rate: 25 cu in / min @ 3500 psi"

Is this normal????

First, what is meant by "internal leak rate"? I am assuming this is the amount of oil that will leak from the "high" side to the "low" side.

To me this means that if I have a cylinder with an area of 7 sq inches, it will drop just over 3" in 1 minute????

I know I won't have 3500 psi on it when it is up holding a load ( I am thinking it will be more like 1500 psi ), I still want a minimum leak so the load will drop the minimum possible over time.

Is there a better brand ( that is still "reasonable" priced ) I should look at or a different type of valve?

I have attached the hydraulic circuit.

Thanks .... Mike

RE: What valve brand do you recommend ?????

Most of them won't be as bad as the spec, but you can't rely on a spool type directional valve to lock a cylinder. To do that, you need a lock valve, like:

http://www.metromachine.com/Hydraulics/Lock%20Valv...

This is not an endorsement of that supplier; just a clear example.

Mike Halloran
Pembroke Pines, FL, USA

RE: What valve brand do you recommend ?????

(OP)
Awesome!

Looking at the lock valve, they are designed for a double acting cylinder.

Since I have a single acting cylinder (using gravity to lower my lift), how can I hook this up in my circuit?

They mention a single lock but don't show an example of it or how it would hook up.

Thanks ..... Mike

RE: What valve brand do you recommend ?????

Search for pilot operated check valve.
Compact Controls, Hydraforce, Sun Hydraulics, for example

Ted

RE: What valve brand do you recommend ?????

(OP)
I understand how the pilot check will work on a double acting cylinder. The "pressure" side will release the check on the side now connected to the tank. With no pressure on both sides, both sides are held by a check valve.

On my single acting cylinder, I am a bit confused.

I "load check" will hold fluid from going back through the circuit on the "power" side.

Because there is gravity down, there is nothing to release a piloted check on the lowering circuit.

In fact, I was going to go with a "poppet" type solenoid valve. They have an incredibly low leak rate ... 3 drops per min.

The only place this will not work is on the valve shown to the left of the circuit. It would work when the system is not energized ... so it would hold the load. I am worried that when lifting there will be higher pressure on the bottom of the valve and then it could bypass the flow control valve and flow directly to the cylinder.

Might be a dumb question but can I put two of these solenoid valves back to back with the check portion pointing in opposite directions?????

I'm sure others make very similar models but here is the ones I was looking at: http://hydraforce.com/Solenoid/Svpp2w.htm

Thanks again ..... Mike

RE: What valve brand do you recommend ?????

(OP)
Kiwitom235 ....

Sorry didn't see your post, you must have been typing the same time I was.

This is exactly what I was looking for!

The valve I was worried about only has to flow in one direction ( during the lowering cycle ) but needs to block in both.

Fantastic!

Thanks so very much .... my wife says if I just had you guys move in for a week or two I could get caught up on all my projects!

Thanks again .... Mike

Just FYI .... Motion Industries quoted me almost $400 for the flow valve with 3-4 weeks delivery. The factory sent me to Brand Power Fluid ( their sister company ) .... $300 and in stock.

RE: What valve brand do you recommend ?????

HAH, funny that, great minds think alike ;)

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close