Danfoss Pilot Operated Check Valves Technical Information

Pilot Operated Check Valves Technical Information

Quick Reference

Pilot to Open	Model No.	Cavity	Description	Flow*	Pressure	Page
	RPC04	NCS04/3	Pilot Operated Check	20.5 l/min	350 bar	PO - 6
			Valve, Pilot to Open	[5.4 US gal/min]	[5075 psi]
	RPC06	NCS06/3		35 l/min	350 bar	PO - 7
				[9.3 US gal/min]	[5075 psi]
	CP450-1	SDC10-3		30 l/min	240 bar	PO - 8
				[8 US gal/min]	[3480 psi]
	RPC12	NCS12/3		90 l/min	315 bar	PO - 9
				[23.8 US gal/min]	[4570 psi]

Pilot to Open	Model No.	Cavity	Description	Flow*	Pressure	Page
	CP458-2	SDC08-3	Pilot Operated Check	20 l/min	210 bar	PO - 10
			Valve, Reverse Pilot to	[5 US gal/min]	[3000 psi]
	MC10-RO	SDC10-3S	Open	45 l/min	250 bar	PO - 11
				[12 US gal/min]	[3600 psi]
	CP451-2	CP12-3S		95 l/min	210 bar	PO - 12
				[25 US gal/min]	[3000 psi]
	CP452-2	SDC16-3S		130 l/min	210 bar	PO - 13
				[34 US gal/min]	[3000 psi]
	CP453-2	CP20-3S		230 l/min	210 bar	PO - 14
				[61 US gal/min]	[3000 psi]

Pilot to Open		Model No.	Cavity	Description	Flow*	Pressure	Page
		RPV 06	NCS06/4	Pilot Operated Check	30 l/min	315 bar	PO - 15
	Drain			Valve, Pilot-to-open with	[8 US gal/min]	[4500 psi]
				drain

* Flow ratings are based on a pressure drop of 7 bar [100 psi] unless otherwise noted. They are for comparison purposes only.

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Pilot Operated Check Valves Technical Information

Quick Reference

Symbol		Model No.	Cavity	Description	Flow*	Pressure	Page
		CP453-5	SDC20-2	Pilot Operated Check	250 l/min	350 bar	PO - 16
				Valve, Reverse Pilot-to-	[66 US gal/min]	[5075 psi]
				open with vent

Pilot to Close	Model No.	Cavity	Description	Flow*	Pressure	Page
	CP460-1	SDC10-3	Pilot Operated Check	45 l/min	210 bar	PO - 17
			Valve, Pilot to Close	[12 US gal/min]	[3000 psi]
	CP461-1	CP12-3S		115 l/min	210 bar	PO - 18
				[30 US gal/min]	[3000 psi]
	CP462-1	SDC16-3S		190 l/min	210 bar	PO - 19
				[50 US gal/min]	[3000 psi]

Dual Pilot-Operated Checks	Model No.	Cavity	Description	Flow*	Pressure	Page
	CP410-1	none	Pilot Operated Check	80 l/min	210 bar	PO - 20
			Valve, Catalog HIC	[21.1 US gal/min]	[3000 psi]

* Flow ratings are based on a pressure drop of 7 bar [100 psi] unless otherwise noted. They are for comparison purposes only.

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Pilot Operated Check Valves Technical Information

Application Notes

MOTION CONTROL	Motion control valves, also referred to as load holding valves, are used to control the
VALVES	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 first two of the above
	requirements.
	· Counterbalance valves will satisfy all four of the above requirements.
	Pilot operated check valves

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Pilot Operated Check Valves Technical Information

Application Notes

PILOT-OPERATED CHECK	Pilot-operated, or pilot-to-open check	Individual cartridges
VALVES	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

A typical circuit application for pilot-

Typical circuit application

operated check valves contains a pump,

W

W

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/flow 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.

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Pilot Operated Check Valves Technical Information

Application Notes

PILOT-OPERATED CHECK VALVES

(continued)

The pressure required to pilot open the check valve can be calculated by:

P = W + (Pc • Ab)		cylinder retracts
	(Ab • R) - Ar
P = W + (Pc • Ar)		cylinder extends
	(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-off, 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 pilot-	Closed center, directional control valves
			Do	Do not

operated 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 intensification creates application concerns, consider using a counterbalance valve.

·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.

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Pilot Operated Check Valves Technical Information

Pilot to Open RPC04

OPERATION

This is a pilot-to-open check valve.

SPECIFICATIONS

Theoretical performance

Pressure drop

26 cSt [121 SUS] hyd.oil at 50ƱC [122 ƱF] psi bar

150 10

	8	3-2
100	6	2-3

504

2

0	0	5	10	15	20	25	30 l/min
		0	2	4		6	8 gal/min

Schematic

Specifications

Rated pressure*	350 bar [5075 psi]
Rated flow at 7 bar	20.5 l/min
[100 psi]	[5.4 US gal/min]
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.

DIMENSIONS	Cross-sectional view
mm [in]
22 mm	42
34-40 Nm
[25-30 lbf*ft]	[1.65]	M18 X 1.5

1	<![if ! IE]> <![endif]>Ø 15 [Ø 0.59]
<![if ! IE]> <![endif]>Ø 14 [Ø0.55]

3	2
6	40.9
[0.24]	[1.61]

<![if ! IE]>

<![endif]>Ø 22 [Ø 0.87]

ORDERING

RPC04-2.5-OR-00-V

INFORMATION

Pilot to Open

Seal Option

Seal Kit

Omit = Buna-N

230000160

V = Viton

230000450

Crack Pressure

0.5

0.5 bar [7 psi]

2.5

2.5 bar [36.25 psi]

Code

Ports & Material

Body Nomenclature

5

5 bar [72.5 psi]

00

00 = Cartridge only

No Housing

8

8 bar [116 psi]

SE1/4

AL, 1/4 BSP

NCS04/3-SE-1/4

15

15 bar [217.5 psi]

SE4S

AL, #4 SAE

NCS04/3-SE-4S

SE6S

AL, #6 SAE

NCS04/3-SE-6S

Pilot Seal Option

** Aluminum bodies are to be used for pressures less than 210 bar

(3000 psi)

Omit

No seals

***Other housings available

OR

Seals

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