Re: Need lesson in tractorology hydraulics terms

Posted by Greg D. on February 14, 2001 at 18:33:54 from (209.240.221.72):

In Reply to: Need lesson in tractorology hydraulics terms posted by Rick from Paso on February 13, 2001 at 18:58:14:

Fudd, the term open center and closed center valves go a lot further than a heat build up as you say.
True, an open center valve does just as you say. With a positive displacement pump as say a gear or vane, oil is passed directly through the valve body when a function is not selected by shifting a spool.
However in a closed center system, it does not allow oil to flow through the valve body thereby requiring a pump of a different type, such as a load sensed piston pump. This will allow the pump to remain on minimm flow until the circuit is selected and thereby sending usually a pilot circuit pressure to the compensator thereby bringing the pump on stroke.
Excavator type systems that are now being used on larger wheel loaders. True there are some exceptions to the gear pumps all being positive displacement, open center systems, but I can only think of one machine that uses it.
Hope that clears up open center -vs-closed center valves

Follow Ups:

Post A Followup Name: E-Mail: Subject: Re: Re: Need lesson in tractorology hydraulics terms Comments: Optional Link URL: Link Title: Optional Image URL: Email Notification: If you check this box, email will be sent to you whenever someone replies to this message. Your email address must be entered above to receive notification. This notification will be cancelled automatically after 2 weeks.

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]