| 摘要 |
The outlet tube entry is formed by two identical half-shells (1) with three square faces and a semicircular face (10). The half-shells have extended side walls (11) so they can fit round the edges of the concrete blocks (40) that are assembled to form the drawing chamber. The concrete blocks are formed so they interlock with each other to form a solid wall. The central part of the block has a thin wall, which can be removed to make way for the circular part of the half-shells.
|
