Open center vs. close center

[Groo]

any good primers out there discussing the pros and cons of each system?
Open center = fixed displacement (for the most part) and closed center = variable displacement.

What is there beyond that? What can closed center do that open centered can't? Anything else out there?

 

[bigdeano]

Google would give you lots of reading material. Aircraft have always used closed center. You only need a pipe big enough for the flow required by each component, not the entire pump flow, so it saves a lot of weight. Also you can operate more than one control at the same time. Important if you don't want to crash.

 

[JD5210]

These youtube videos maybe more than you are looking for. I found them to be every informative

Hydraulics Math - YouTube

 

[/pine]

With a closed center system pressure lines can be tee'd

I have a Ditch Witch 3610 and it has both open and closed center systems...

 

[chevy791979]

Closed center is far more fuel efficient and heat efficient. It only uses what oil it is told to move by the pilot oil input from the operator. And flow adjustability with L/S pump is good for motors and such that require a certain flow to work safely.

 

[majorwager]

Chevy is exactly correct. Heat is the issue, very destructive. I have a older IH tractor, open center, and the hyd operating temp pushes the boundaries even if no oil is feeding a motor or cylinder. It is very rare to find closed center systems in sub-100 hp tractors.

 

[Tx Jim]

Closed center is far more fuel efficient and heat efficient.

Closed center hyd system that develops a high pressure internal leak can have heating problems. More fuel efficiency is determined by number of hyd functions that are performed. My guess is a 50 or 55 series JD tractor hyd pump is out of stroke for a very limited amount of time. Then when operating a hyd motor it never goes out of stroke.

 

[chevy791979]

Closed center hyd system that develops a high pressure internal leak can have heating problems. More fuel efficiency is determined by number of hyd functions that are performed. My guess is a 50 or 55 series JD tractor hyd pump is out of stroke for a very limited amount of time. Then when operating a hyd motor it never goes out of stroke.

Internal leaks are considered a malfunction.

I will have to disagree with you on the fuel efficient statement. If you took 10 circuits for both types and both running all hyd motors a closed center will out perform an open center all day long. You can tune a closed center to match needed flow. The open center is all or nothing.

 

[Tx Jim]

Internal leaks are considered a malfunction.

I will have to disagree with you on the fuel efficient statement. If you took 10 circuits for both types and both running all hyd motors a closed center will out perform an open center all day long. You can tune a closed center to match needed flow. The open center is all or nothing.

Have you ever operated an orbit motor on a JD CC hyd system? Evidently not.

 

[chevy791979]

Have you ever operated an orbit motor on a JD CC hyd system? Evidently not.

Once or twice