Danfoss Pilot Operated Check Valves Technical Information
Pilot Operated Check Valves Technical Information
Drain
Quick Reference
Pilot to Open Model No. Cavity Description Flow* Pressure Page
RPC04 NCS04/3 Pilot Operated Check
Valve, Pilot to Open
RPC06 NCS06/3 35 l/min
CP450-1 SDC10-3 30 l/min
RPC12 NCS12/3 90 l/min
Pilot to Open Model No. Cavity Description Flow* Pressure Page
CP458-2 SDC08-3 Pilot Operated Check
Valve, Reverse Pilot to
MC10-RO SDC10-3S 45 l/min
CP451-2 CP12-3S 95 l/min
CP452-2 SDC16-3S 130 l/min
CP453-2 CP20-3S 230 l/min
Open
20.5 l/min
[5.4 US gal/min]
[9.3 US gal/min]
[8 US gal/min]
[23.8 US gal/min]
20 l/min
[5 US gal/min]
[12 US gal/min]
[25 US gal/min]
[34 US gal/min]
[61 US gal/min]
350 bar
[5075 psi]
350 bar
[5075 psi]
240 bar
[3480 psi]
315 bar
[4570 psi]
210 bar
[3000 psi]
250 bar
[3600 psi]
210 bar
[3000 psi]
210 bar
[3000 psi]
210 bar
[3000 psi]
PO - 6
PO - 7
PO - 8
PO - 9
PO - 10
PO - 11
PO - 12
PO - 13
PO - 14
Pilot to Open Model No. Cavity Description Flow* Pressure Page
RPV 06 NCS06/4 Pilot Operated Check
Valve, Pilot-to-open with
drain
* Flow ratings are based on a pressure drop of 7 bar [100 psi] unless otherwise noted. They are for comparison
purposes only.
30 l/min
[8 US gal/min]
315 bar
[4500 psi]
PO - 15
BC332375625108en-000101 • February 2020
PO - 1
Pilot Operated Check Valves Technical Information
Quick Reference
Symbol
Pilot to Close Model No. Cavity Description Flow* Pressure Page
Dual Pilot-Operated Checks
Model No. Cavity Description Flow* Pressure
CP453-5 SDC20-2 Pilot Operated Check
Valve, Reverse Pilot-to-
open with vent
CP460-1 SDC10-3 Pilot Operated Check
Valve, Pilot to Close
CP461-1 CP12-3S 115 l/min
CP462-1 SDC16-3S 190 l/min
Model No. Cavity Description Flow* Pressure Page
CP410-1 none Pilot Operated Check
Valve, Catalog HIC
250 l/min
[66 US gal/min]
45 l/min
[12 US gal/min]
[30 US gal/min]
[50 US gal/min]
80 l/min
[21.1 US gal/min]
350 bar
[5075 psi]
210 bar
[3000 psi]
210 bar
[3000 psi]
210 bar
[3000 psi]
210 bar
[3000 psi]
Page
PO - 16
PO - 17
PO - 18
PO - 19
PO - 20
* Flow ratings are based on a pressure drop of 7 bar [100 psi] unless otherwise noted. They are for comparison
purposes only.
BC332375625108en-000101 • February 2020
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Pilot Operated Check Valves Technical Information
Application Notes
MOTION CONTROL
VALVES
Motion control valves, also referred to as load holding valves, are used to control the
motion of a load in the following ways:
· Prevent a load from dropping in case of hose or tube failure.
· Prevent a load from drifting caused by directional control valve spool leakage.
· Provide smooth, modulated motion when the load is in a lowering or run-away
mode.
· Provide smooth, modulated motion when the directional control valve is suddenly
closed.
There are two basic types of motion control valves:
· Pilot-operated, or pilot-to-open check valves will satisfy the rst two of the above
requirements.
· Counterbalance valves will satisfy all four of the above requirements.
Pilot operated check valves
BC332375625108en-000101 • February 2020
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Pilot Operated Check Valves Technical Information
Application Notes
PILOTOPERATED CHECK
VALVES
Pilot-operated, or pilot-to-open check
valves will positively hold a pressurized
load and will release the load upon
application of a pressure signal to the
pilot port. Pilot-operated check valves
are available as individual cartridges,
standard Cartridge-In-Body (CIB)
packages, or can be created in custom
manifolds by using a standard check
valve such as CV10-NP with a guided
pilot piston. For more information on
pilot pistons, see Accessories.
Cartridge in body
Individual cartridges
A typical circuit application for pilotoperated check valves contains a pump,
directional control valve, and an actuator.
Without a pilot-operated check valve the
load will drift down due to spool leakage
if the directional control valve is centered
with the load raised. Additionally
there is no protection against the load
dropping in the event of hydraulic line
failure. Adding a pilot-operated check
valve helps prevent cylinder drift and
provides protection against hose or
tube failure. In this circuit, moving the
directional control valve to the right
causes the cylinder to extend. When the
directional control valve is centered, the
pilot-operated check valve will prevent
leakage and lock the cylinder in position. Moving the directional control valve to the
right sends pressure/ow to the rod end of the cylinder. This pressure also acts on the
pilot piston to open the check valve and allow the load to be lowered.
Typical circuit application
W W
BC332375625108en-000101 • February 2020
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Pilot Operated Check Valves Technical Information
Application Notes
PILOTOPERATED CHECK
VALVES
(continued)
The pressure required to pilot open the check valve can be calculated by:
W + (Pc • Ab)
P =
(Ab • R) - Ar
W + (Pc • Ar)
P =
(Ar • R) - Ab
W = Load
Pc = Check valve crack pressure (typically 0.34-4.5 bar [5-65 psi]; consult catalog sheets
for details)
Ab = Cylinder bore area
Ar = Cylinder rod area
R = Check valve pilot ratio (typically 3:1 or 4:1; consult catalog sheets for details)
Note that these equations are idealized and do not consider any backpressure in the
circuit, which is additive to the pressure required to pilot open the check valve.
Some additional guidelines for pilot-operated check valve applications:
· Use pilot-operated check valves for load holding, not for motion (speed) control.
Pilot-operated check valves are on-o, non-modulating devices. Trying to
use a pilot-operated check valve to control an overrunning load can result in
severely unstable motion. For motion (speed) control of overrunning loads, use a
counterbalance valve.
· Use caution when applying pilotoperated check valves to the rod
end of a cylinder. Cylinders with
large rod:bore diameter ratios may
intensify rod pressure to a point
where the required pilot pressure
may be dangerously high—
refer to the above equations. If
intensication creates application
concerns, consider using a
counterbalance valve.
cylinder retracts
cylinder extends
Closed center, directional control valves
Do Do not
· Do not use pilot-operated check valves with closed-center, directional control valves.
Pressure trapped between the directional control valve and the pilot-operated check
valve can pilot the check valve open and result in undesired load motion.
· Locate pilot-operated check valves at or near the actuator to provide maximum load
holding protection in the event of hydraulic line failure.
BC332375625108en-000101 • February 2020
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Pilot Operated Check Valves Technical Information
2
100
0
3-2
2-3
6
4
5
30252015
l/min
10
10
8
Pressure drop
gal/min
86
4
2
psi
bar
0
0
150
50
26 cSt [121 SUS] hyd.oil at 50ƱC [122 ƱF]
Ø 22
[Ø 0.87]
Ø 14
[Ø 0.55]
Ø 15
[Ø 0.59]
6
[0.24]
40.9
[1.61]
42
[1.65]
3
2
1
34-40 Nm
[25-30 lbf*ft]
22 mm
M18 X 1.5
RPC04-2.5-OR-00-V
00 = Cartridge only
Ports & Material
Code
00
15 bar [217.5 psi]15
5
0.5
8
Crack Pressure
8 bar [116 psi]
0.5 bar [7 psi]
2.5 bar [36.25 psi]
Seal Option Seal Kit
Omit = Buna-N
V = Viton
SE1/4 AL, 1/4 BSP
SE4S AL, #4 SAE
SE6S
AL, #6 SAE NCS04/3-SE-6S
NCS04/3-SE-4S
NCS04/3-SE-1/4
Body Nomenclature
No Housing
** Aluminum bodies are to be used for pressures less than 210 bar (3000 psi)
***Other housings available
OR
Omit
Pilot Seal Option
5 bar [72.5 psi]
2.5
Pilot to Open
230000450
230000160
No seals
Seals
Pilot to Open
RPC04
OPERATION
SPECIFICATIONS
DIMENSIONS
mm [in]
This is a pilot-to-open check valve.
Theoretical performance
Cross-sectional view
Schematic
Specications
Rated pressure* 350 bar [5075 psi]
Rated ow at 7 bar
[100 psi]
Weight 0.06 kg [0.13 lb]
Pilot ratio 3.2:1
Cavity NCS04/3
*Rated Pressure based on NFPA fatigue test
standard (at 1 million cycles)
Note: A piston seal requires a 5 bar [72.5 psi] or
greater return spring.
20.5 l/min
[5.4 US gal/min]
ORDERING
INFORMATION
BC332375625108en-000101 • February 2020
PO - 6
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