A pneumatic flow control valve works by using a needle valve to meter airflow in one direction and a check valve to allow free flow in the opposite direction.
Here's a more detailed breakdown:
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Needle Valve: This is the core component responsible for controlling the airflow. A needle (a tapered pin) is positioned within a small orifice. By adjusting the needle's position (usually by turning a screw), you can change the size of the opening and thus the amount of air that can pass through. Closing the needle valve restricts airflow, while opening it increases airflow.
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Check Valve: The check valve is a one-way valve. It allows air to flow freely in one direction but blocks airflow in the opposite direction.
How it Works Together:
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Flow Control Direction: When air flows through the valve in the direction where flow control is desired, it must pass through the needle valve's restricted orifice. The needle valve's setting determines the rate of flow.
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Free Flow Direction: When air flows in the opposite direction, it bypasses the needle valve by opening the check valve. This allows air to flow freely and without restriction.
In summary: A pneumatic flow control valve provides adjustable flow restriction in one direction and unrestricted flow in the opposite direction, combining the functionality of a needle valve and a check valve. This allows precise control of the speed of pneumatic actuators, such as cylinders.
