Center vs Power Beyond

[Tx Jim]

RickB
Thanks for the PBY explanation.
Jim

 

[ddgood]

Closed center systems use variable volume pressure compensated pumps which are far more expensive than gear pumps. These are typically used on higher horsepower tractors and construction equipment vs lower cost CUTs. These do not require power beyond since the pump destrokes and only produces flow on demand. The valves are connected in parallel on these systems also much easier to run multiple functions simultaneously.

Open center: used fixed displacement pumps typically gear. These produce flow whenever the pump is turning. These require power beyond so that flow goes from one valve, to the next in series. Usually more difficult to operate multiple functions simultaneously

Guesstimate on prices: 10 GPM Gear pumps for CUTs are maybe $500 while similar sized variable volume could be $1500 - $2000

Ultimately decision to use closed center vs open depends on system requirements, cost, etc.

^^^^ This is a great writeup and I found a very good graphic (and good writeup too) at: Open and Closed Center Hydraulic Systems

As a control engineer designing and building electro-hydraulic control systems for oil and gas drilling and completion operations, I generally utilize closed center valve systems, with accumulator storage and pressure compensated, variable displacement pumps. Most of the time, the pumps are under PLC control and we can turn them on or off as the hydraulic flow requirements dictate vs having to leave them running all the time like an open center system would require. This helps reduce heat loading in the system, lower energy costs, etc.