Circuit types – parallel circuit, Schematic circuit types, Open-center directional control valve vo40 – Parker Hannifin VO40 User Manual
Page 10: Circuit types – tandem circuit (priority), Technical information
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Parker Hannifin Corporation
Open-Center Directional Control Valve
VO40
Catalog HY17-8505/UK
Circuit Types – Parallel Circuit
In the open-center parallel circuit, oil flows through the open-center passage when all of the spools are in neutral.
When spools are shifted, oil is diverted into the parallel path and available to each of the selected work-sections.
Simultaneous operation can be achieved, when two or more spools are selected. However, since oil will take the
path of least resistance the operator must meter the flow to each function to get a desired function speed.
Circuit Types – Tandem Circuit (Priority)
In the open-center tandem circuit, oil flows through the open-center passage when all of the spools are in neutral.
Tandem work-sections are fed from the open center and the parallel path is blocked. A tandem work-section will
give priority to an upstream work-section.
B A
P1
[26]
T1
[24]
G
B A
B
A
T4
[34]
B A
P1
[26]
T1
[24]
T4
[34]
B A
B
A
Technical Information