| 摘要 |
The housing (1) contains a flap (2) mounted on an angled axle (15) with one arm (50) parallel, in an open position, with the pipe's axis, in a backward flow direction; and the other arm (51), in a closed position, at right angles to the pipe's axis. Two parallel spring elements (21) are attached to a bar (28) penetrating the housing wall (5) and grip the lever arm (17) fixed to the flap. The bar has a scale on its casing (25) on the outer housing wall, with a transverse part (29) possessing a thread for a threaded pin (32) supported on a casing's base part (23,27). The bar is freely movable in and or with the transverse part. |
