Parker Hannifin manual Ordering Information Work Sections VO40, Work Section Circuitry

Catalog HY17-8505/UK	Open-Center Directional Control Valve
Ordering Information – Work Sections	VO40

The VO40 valve can be supplied in combinations from one to ten work sections. For each work section there is a variety of spool options, actuators, positioners and port accessories. Work sections can have parallel, series, and/or tandem circuitry. All types can be combined in the same valve assembly.

All work sections with hold in neutral spools have transition checks (load checks). All work sections with free flow in neutral spools (motor) do not include transition checks (load checks). Contact Parker if you require a deviation from this configuration.

Work sections are available with or without work port option machining. Integrated pilot-operated checks (Lock- Out) are available in a specially machined casting (ordering code on page 20 [76 A/B]). A spacer section which provides for more spacing between sections is also available (ordering code on page 20 [90]).

Examples of work port machining options:

Section without RV Cavities Section with RV Cavities

Section with PO Checks

The VO40 Pilot-Operated Check (Lock-Out) sections provide near zero leakage and can prevent cylinder drift when the spool is in the neutral position. When the spool is shifted to a power position, oil is directed to one work port. Return oil is momentarily blocked until pilot pressure unseats the check (3.1:1 ratio). With 207 bar (3000 PSI) load, it will require 67 bar (968 PSI) into the opposite work port to unlock.

The spool is a 4-way, 3-position free flow spool which prevents system pressure leakage from building up and unlocking the PO checks.

The coding to specify a work section is made by 11 fields, as shown below:

[47]– Work Section Circuitry

P Parallel Circuitry.

TTandem Circuitry – Provides priority to upstream sections.

SSeries Circuitry– (In development).

16 Parker Hannifin Corporation