Air Bleeding During Hydraulic System Startup

When starting up a hydraulic system after a new installation, service, or extended downtime, it’s common for air to enter the system.

Problems Caused by Air in the Hydraulic System

Air in the system can be compressed, leading to:

• Less accurate and reliable system performance – which can even pose safety risks

• Cavitation, which may cause severe damage to the hydraulic pump

Sun Hydraulics’ air bleeding/start-up valves solve the problem of trapped air in hydraulic systems. The valve typically purges oil to the tank to release trapped air. It automatically closes once the pressure drop reaches a certain level — meaning the air has been removed from the oil. Another advantage is that the system is soft-started, which is gentler on the hydraulic pump and electric motor.

Air Bleeding and Start-Up Valve – NQEB

The NQEB air bleeding valve purges oil to release trapped air. It closes when the pressure drop becomes too high, indicating that the oil is free from air.

• Available in size T-3A, 15 to 200 l/min

• Closes after approx. 12 seconds at 15 l/min and 0.5 seconds at 200 l/min

• The valve reopens when the pressure drops below 1.7 bar

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