The semi-automatic switching device is a gas collecting system with two container lines, A and B. Each line has two parallel regulators.
Gas starts flowing from the container line (A) with the higher set value, and when its gas level gets low, the system automatically switches to container line (B) without changing the flow rate.

To replace an empty container in line (A) with a filled one, rotate the switching lever 180° or move the adjustment handle, making the secondary pressure of line (B) higher, ensuring stable gas supply from line (B).
When line (B) gets low, the system switches back to line (A).

By repeating this process, continuous gas supply is maintained. Installing a pressure gauge with a lower limit contact on the primary side, connected to an alarm panel, allows for easy monitoring.
A buzzer and patrol lamp indicate when container replacement is needed.