Abstract: The manhole has a frame 1 with a flange 4 to be embedded in the road and a movable cover 2 to fit in the cylindrical wall 3 of the frame. On its inside the wall 3 has three support surfaces 9 each downwardly sloping at an angle .alpha. to the horizontal in the circumferential direction and at an angle .beta. to the horizontal in the radial direction. Between the surfaces 9 the frame has three undercut surfaces 11 extending radially. On its underside the cover 2 has six surfaces 14, 15. When the cover is on the frame three surfaces 14 are parallel to the corresponding surfaces 9 and the three surfaces 15 are parallel to the corresponding surfaces 11. The surfaces 9, 11 on the frame abut the surfaces 14, 15 by which the cover is held against rocking.

Abstract: The apparatus comprises a vat (1) in the bottom of which a certain number filling devices (22) are arranged around the axis of the vat. Each device contains a filling pipe in communication with the vat (1) and which is traversed by a vent tube which is connected at its top with a connection pipe (54) outside the vat and debouching in the upper part of an air-liquid separator (56). The lower part of this separator is connected to a vat of liquid (64) by means of a pipe (62). At its top it is connected by pipes (58) to a pipe (60) in which the pressure is lowered. Since the vat is mounted on a rotary shaft (4), the pipe (60) is connected to the pipe (58) by a rotary joint on the cover of the vat. Likewise, a pressurized pipe from the vat is mounted, by means of the same rotary joint, inside the cover of the vat.

Abstract: Filler material and process for the heterogeneous welding by fusion of two iron-carbon alloys. The filler material comprises iron and at least one element for producing special stable carbides and at least one element for nodularizing graphite in iron.