Valve education?

[dcyrilc]

By CC, I presume you mean closed center. Is this true and do you know the difference between closed center and open center hydraulic systems?

If not where did you get the CC requirement from?

Once these questions are answered we can go on to these.

What do you want to do with this valve?

How are you going to plumb it in?

Roy

Yes, my JD 2240 has Closed Center hydraulics. Open Center is Constant Flow & Closed Center is Constant Pressure usually with a variable displacement pump.

Initially, 3 valves will be for T&T with tilt control on both sides. 2 additional valves will be for future rear remotes.

The pressure line will be plumbed from the (currenly plugged) factory port on the priority valve where factory rear remotes are plumbed from. The return can be plumbed back to the filter or to the resivior or both. Factory remotes are plumbed to the filter with an optional kit allowing a split return to both the filter and resivior.

I plan to use stack valves to create the configuration I want, however this post came about when I began looking at valves and was lost in the abbreviated names of the valves. IE:SVS1GA1AA (DA CYL SERIES SPOOL SPRING CENTERED) $114.00 & SVW1BA1 (DA CYL SPOOL SPRING CENTERED) $67.00. I've yet to figure out the difference between these two valves. I guess it comes down to that I don't know what a series spool is. Both of these are listed under 1 SPOOL SV CLOSED CENTER NO RELIEF in the area for stack valves on Surplus Centers website.

I started this thread because I realized that I didn't know terminology well enough to properly understand what the valves were that I was looking at by the descriptions. I've figured out some of the abbriviations, such as SA - Single Acting, DA - Double Acting.

After realizing the short commings in my understanding of terminology, I decided to start this thread both for my own knowledge and also so that others can learn as well.

I realize that nearly all newer tractors are Open Center, so the plumbing requirements for my tractor will be different from most of what is dealt with here on TBN. I don't plan to get into exact plumbing plans here as this thread is for education of terminology rather the actually plumbing my machine.

 

[J_J]

Some of the valves are listed as OC, but have a Closed Center option like the one below.

https://www.surpluscenter.com/item.asp?UID=2228012222205977&item=9-6702-F&catname=hydraulic


Question.

If an SA cyl attached to this valve, Is there a good reason that Prince recommends that port A be plugged, and the cyl connected to port B?

 

[dcyrilc]

Some of the valves are listed as OC, but have a Closed Center option like the one below.

https://www.surpluscenter.com/item.asp?UID=2228012222205977&item=9-6702-F&catname=hydraulic

Thanks J_J.
I've noticed that some of the Open Center valves offer optional plugs/inserts for Closed Center or Power Beyond.

 

[AKKAMAAN]

Question.

If an SA cyl attached to this valve, Is there a good reason that Prince recommends that port A be plugged, and the cyl connected to port B?

1. Do you mean why A port is plugged at all??


2. Or do you mean why not B port is plugged and cyl connected to A port?


answer to #2....My self, I think it would make more sense to connect cyl to A port and plug B....but it is just a matter of what side of the spool that have the lands for a plugged port.
Like Prince shows on this Serie20 3 way spool.....B port is Obviously plugged on this one....see symbol....

Woops...my bad....of course A port is plugged in this one too....

 

[dcyrilc]

1. Do you mean why A port is plugged at all??


2. Or do you mean why not B port is plugged and cyl connected to A port?


answer to #2....
My self, I think it would make more sense to connect cyl to A port and plug B....but it is just a matter of what side of the spool that have the lands for a plugged port. Like Prince shows on this Serie20 3 way spool.....B port is Obviously plugged on this one....see symbol....

So is the "A" work port not blocked in neutral?

I think I just answered my own question. "One way motor valve" the "A" port is not blocked because of possible torque from the motor. If connected to the "A" port, an SA cylinder would bleed down when the valve is in neutral. Correct?

 

[AKKAMAAN]

So is the "A" work port not blocked in neutral?

On the one J_J refers too , YES, on the one I show, NO, and they are two different Prince valves....I noticed this "discrepancy" a while ago.....no biggie....but a little disturbing....because it is inconsistant....I think that it is, sort of, common custom in valve industry, to have B port plugged, if it is a 3way valve for a single acting cylinder....


WOOOPPS my bad...to tired.....sorry....A port of course plugged on my picture too...

 

[dcyrilc]

On the one J_J refers too , YES, on the one I show, NO, and they are two different Prince valves....I noticed this "discrepancy" a while ago.....no biggie....but a little disturbing....because it is inconsistant....

I think that it is, sort of, common custom in valve industry, to have B port plugged, if it is a 3way valve for a single acting cylinder....

I was looking at your picture and trying to figure out why "B" and not "A". Didn't realize they were different valves.

Another example of how much I need to learn before purchasing valves and why this should be a good thread for the beginner.

 

[dcyrilc]

1. Do you mean why A port is plugged at all??


2. Or do you mean why not B port is plugged and cyl connected to A port?


answer to #2....
My self, I think it would make more sense to connect cyl to A port and plug B....but it is just a matter of what side of the spool that have the lands for a plugged port. Like Prince shows on this Serie20 3 way spool.....B port is Obviously plugged on this one....see symbol....

Can you give some explaination of the meaning of the different parts of the schematic you gave in this post. What does the symbot on the left edge mean, and what does each section from left to right mean, and lastly what is the symbol on the right?

 

[AKKAMAAN]

I was looking at your picture and trying to figure out why "B" and not "A". Didn't realize they were different valves.

Another example of how much I need to learn before purchasing valves and why this should be a good thread for the beginner.

Sorry dcyrilc....I messed up here A port is plugged on both J_J's valve and the valve I referred to....But I still stick with my other statements.....
I changed the picture too....Wish I could UNDO the whole thing....LOL...well good night now....
Later
Per

 

[kennyd]

I guess it comes down to that I don't know what a series spool is.

FarmerFord did a excellent job of describing series vs. parallel valves in post #7 of THIS thread. Also the link provided by Shaley is great also. The short story is though for loader and backhoe valves parallel is preferred because you are often doing more than one function at a time. You would not need that for your remote valve so save the money and go with the series.