Flow Control Valve Open

Flow Control Valve Open

• A To Valve Body Unit
• B Pump
• C Metering Orifice
• D Flow Control Valve

Fluid from the pump runs through a metering orifice to the valve body unit. This creates a pressure difference between the pump and valve body unit sides of the orifice. When pressure in the pump side is higher than the force of the spring holding the flow control valve closed, it pushes the valve down (open), and excess fluid returns to the pump inlet. The combined effect of the metering orifice and the flow control valve provides a relatively constant flow of fluid to the valve body unit.

Pressure Relief Valve

Relief Valve Open

• A Flow Control Valve
• B Relief Valve
• C Damping Orifice

As pressure on the valve body unit side builds up, it pushes the relief valve ball (inside the flow control valve) up against its spring, and excess fluid returns to the pump inlet. As the pressure under the flow control valve drops, the relief valve ball is closed by its spring, and the flow control valve is forced down again, allowing excess fluid from the pump side to return to the inlet. This flow control valve/relief valve cylinder keeps pump output pressure between 8,000 – 9,000 kPa.