There is a larger metal block that can be assembled with the previous one.
On the left and right sides of this larger metal block, there are through holes.
Then, it is assembled with the previous metal block, where the holes on the top metal block perfectly align with the ends of the pipe below.
The bottom of this larger metal block is big enough to enclose the upper metal block, and it is locked in place with iron stakes.
Then, a curved pipe is cast, with one end connecting inside the iron kettle, and the other end branching with two holes that can perfectly fit with the previous metal block with two holes, aligning their apertures.
A metal plate is clamped between them.
The metal plate has two holes and can be pushed left or right. When pushed forward, the left hole allows the left pipe of the two metal blocks to connect, while the right pipe remains closed; when pulled backward, the left pipe is closed and the right pipe is connected.
