The cutter blade (2) is consisted of an upper bottom surface (21), a lower bottom surface (22) and a side face (23) connecting the upper bottom surface (21) and the lower bottom surface (22).

An element bottom plate designed for fastening to the wall element's lower bottom plate.

The bottom plate (4) is double-structured including a lower bottom plate (41) on a lower part and an upper bottom plate (42) on an upper part, which are vertically separate from each other.

The apparatus generally include a lower bottom plate and an upper bottom plate defining a first plenum.

A space between the lower bottom plate (41) and the upper bottom plate (42) is densely filled with crushed stones (43).

An upper bottom surface of the cylindrical connecting portion (11) and a lower bottom surface of the conical transition portion (12) are coplanar.

A raised floor is formed in a bottom interior section of the lower piece.

The molded lower portion (222) includes an integral floor (232), instead of a separate floor piece.

The lower plate attaches to the head cover to define a separation chamber between an upper internal surface of the head cover and a lower internal surface of the lower plate.

Bottom text black with white background

Bottom text black with white background

Lower section (103) comprises the floor of the box.

Bottom text black with white background

Circle and line red with white background

The lower end of the sealing member (33) clings to the bottom lower plate (12).