Flowcontrollers

Controlling the flow in a membrane module is essential for producing nitrogen or oxygen with consistent purity and a stable residual oxygen content. Proper and stable flow ensures optimal membrane performance and delivers consistent gas specifications.

Flow Controller vs. Needle Valve: The Difference

A flow controller is specifically designed to maintain a constant flow, regardless of pressure changes. In contrast, a needle valve's flow is significantly influenced by the difference between the inlet and outlet pressure of the membrane.

The greater the pressure difference, the faster the airflow. This results in lower nitrogen purity. Therefore, a needle valve is less suitable for applications where stable gas purity is critical.

How Does a Mechanical Flow Controller Work?

A mechanical flow controller automatically compensates for pressure differences.

• When the outlet pressure increases (e.g., when pressure in a buffer tank rises), the flow remains stable.
• When the outlet pressure decreases, the flow does not simply increase. Instead, the controller adjusts to maintain the desired constant flow.

This happens because the flow controller increases the opening with a small pressure difference and decreases it with a large pressure difference.

Minimum Pressure Difference Required for Proper Operation

A minimum pressure difference is required for proper operation.

If the pressure on the inlet and outlet sides is exactly the same, no flow can occur—there is nothing to regulate in that case.

For our flow controllers, a minimum required pressure difference of 1 bar applies. If the difference is smaller, the flow will decrease, and constant production of nitrogen or oxygen can no longer be guaranteed.

A pressure vessel (or buffer tank) is an essential component of any compressed air or nitrogen system. It is used to absorb the difference between the supplied flow rate and the actual consumption. This creates a stable, efficient, and reliable system, suitable for both industrial compressed air installations and nitrogen generators.