Spartan Equipment SKID-PAC 1000, Technical Manual

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Spartan Equipment Technical Manual Skid-Pac
TM
1000, 1000B
7
IMPORTANT
The Operating Pressure is not to be used
as a relief valve pressure setting. Poor
performance and significant heat
generation will occur.
Dynamic Relief Pressure - The
pressure when the relief valve first
“cracks” open and allows a small
amount of oil to by-pass through the
valve.
IMPORTANT
The carrier's hydraulic system shall be
capable of providing the desired oil flow at
a pressure equal to at least the dynamic
relief pressure.
Static Relief Pressure - The pressure
when the relief valve is fully open and
the entire oil flow is by-passed through
the valve. At no time is it permissible to
subject the Spartan Equipment
attachment to Static Pressures that
exceed the values listed in Section 6.
IMPORTANT
The relief valve is a safety device, used to
protect the circuit against hydraulic
overload. It is a required component.
When selecting a relief valve for Spartan
Equipment attachments, the pilot controlled
relief valve is better suited for high flow
applications. Pilot controlled relief valves
generally exhibit shorter opening curves,
compared to direct acting relief valves.
Opening Curve
– The range or stroke of
the relief valve from the point that it first
cracks open (Dynamic) to when it has
reached the fully open position (Static).
Several factors influence the opening
curve, including spring rate, volume and
viscosity of the fluid passing through the
valve.
The cracking pressure (dynamic) is
always less than the static pressure. A
relief valve set to a dynamic pressure of
3000 psi (200 Bar) will crack open when
this pressure is reached, but fully opens
at a higher pressure.
Operating Pressure
Dynamic Relief Pressure
(Relief valve cracks open)
FLOW
Hydraulic
Flow Range
Opening
Curve
Attachment
Operational
Range
Operating
Pressure
Range
Static Relief Pressure
(No flow to attachment)
PRESSURE
Figure 5-1
Flow-Pressure Diagram