Created on 12/14/2016

 2016 Sun Hydraulics Corporation See www.sunhydraulics.com for detailed product information 1 of 2

MODEL

CWBG

4.5:1 pilot ratio, vented counterbalance valve

SERIES 1 / CAPACITY: 30 L/min. / CAVITY: T-21A

4-Port Vented

4-Port Vented, Non-adjustable

Vented counterbalance valves with pilot assist are meant to control an overrunning load. The check valve allows

free flow from the directional valve (port 2) to the load (port 1) while a direct-acting, pilot-assisted relief valve

controls flow from port 1 to port 2. Pilot assist at port 3 lowers the effective setting of the relief valve at a rate

determined by the pilot ratio. Backpressure at port 2 does not affect the valve setting because the spring chamber

references the vent (port 4).

Other names for this valve include motion control valve and over-center valve.

TECHNICAL DATA

Cavity T-21A

Series 1

Capacity 30 L/min.

Pilot Ratio 4.5:1

Maximum Recommended Load Pressure at Maximum Setting 215 bar

Maximum Setting 280 bar

Factory Pressure Settings Established at 30 cc/min.

Maximum Valve Leakage at Reseat 0,3 cc/min.

Check Cracking Pressure 2,8 bar

Reseat >85% of setting

Valve Hex Size 22,2 mm

Valve Installation Torque 41 - 47 Nm

Adjustment Screw Internal Hex Size 4 mm

Locknut Hex Size 15 mm

Locknut Torque 9 - 10 Nm

Seal kit - Cartridge Buna: 990021007

Seal kit - Cartridge Polyurethane: 990021002

Seal kit - Cartridge Viton: 990021006

Model Weight 0.20 kg.

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CWBG

Created on 12/14/2016

 2016 Sun Hydraulics Corporation See www.sunhydraulics.com for detailed product information 2 of 2

(L)CONTROL

L Standard Screw Adjustment

C Tamper Resistant - Factory Set

(H)FUNCTIONAL SETTING RANGE

H 1000 - 4000 psi w/25 psi Check (70 -

280 bar w/ 1,7 bar Check), 3000 psi

(210 bar) Standard Setting

(N)SEAL MATERIAL

N Buna-N

V Viton

MATERIAL/COATING

Standard Material/Coating

/AP Stainless Steel, Passivated

/LH Mild Steel, Zinc-Nickel

TECHNICAL FEATURES

Counterbalance valves should be set at least 1.3 times the maximum load induced pressure.

Turn adjustment clockwise to decrease setting and release load.

Full clockwise setting is 200 psi (14 bar).

Free-flow check capacity (port 2 to port 1) is equivalent to the CAC* and CWC* models but the piloted-open flow capacity (port 1 to port 2) is reduced. See

performance curve.

All 4-port counterbalance and pilot-to-open check cartridges are physically interchangeable (i.e. same flow path, same cavity for a given frame size), however, the

model CWBG has a reduced overall length, allowing for easier packaging.

Reseat exceeds 85% of set pressure when the valve is standard set. Settings lower than the standard set pressure may result in lower reseat percentages.

Sun counterbalance cartridges can be installed directly into a cavity machined in an actuator housing for added protection and improved stiffness in the circuit.

This valve has positive seals between all ports.

With vented valves, a lower pilot ratio may be required to achieve machine stability compared to non-vented valves.

Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge

machining variations.

PERFORMANCE CURVES

Model Code Example: CWBGLHNCONFIGURATION OPTIONS