Abstract: A multiple hearth furnace including a rabble arm with a tubular structure and a solid plug body. The latter is received in a socket arranged in an arm fixing node. It has an axial through boring and cooling fluid supply and return channels arranged around this through boring. A clamping bolt is rotatably fitted in the through boring. It has a bolt head, which can be brought by rotation into and out of hooking engagement with an abutment surface on the arm fixing node. A threaded end of the clamping bolt sticks out of the through boring at the rear end of the plug body. A threaded sleeve, which is screwed onto this threaded end, bears on an abutment surface at the rear end of the plug body for exerting a clamping force onto the clamping bolt.

Abstract: A multiple hearth furnace including a rabble arm with a tubular structure and a solid plug body. The latter is received in a socket arranged in an arm fixing node. It has an axial through boring and cooling fluid supply and return channels arranged around this through boring. A clamping bolt is rotatably fitted in the through boring. It has a bolt head, which can be brought by rotation into and out of hooking engagement with an abutment surface on the arm fixing node. A threaded end of the clamping bolt sticks out of the through boring at the rear end of the plug body. A threaded sleeve, which is screwed onto this threaded end, bears on an abutment surface at the rear end of the plug body for exerting a clamping force onto the clamping bolt.

Abstract: A multiple hearth furnace includes a gas cooling system for its central shaft and its rabble arms. This gas cooling system includes within the shaft an annular main distribution channel for supplying a cooling gas to the rabble arms and a central exhaust channel for evacuating the cooling gas leaving the rabble arms. The gas cooling system further includes an annular main supply channel surrounding the annular main distribution channel and being outwardly delimited by an outer shell of the shaft. A cooling gas inlet is connected to the annular main supply channel. A cooling gas passage between the annular main supply channel and the annular main distribution channel is spaced from the cooling gas inlet, so that cooling gas supplied to the cooling gas inlet has to flow through the annular main supply channel through several hearth chambers before it flows through the cooling gas passage into the annular main distribution channel.

Abstract: A rabble arm for a furnace includes an elongated metallic support core, at least one rabble tooth having a rabble portion and a fixing portion and a fixing device co-operating with the fixing portion for fixing the rabble tooth to the elongated metallic support core. The fixing portion includes a through hole through which the elongated metallic support core axially passes. The fixing device co-operates with the fixing portion around the through hole for fixing the rabble tooth to the elongated metallic support core.

Abstract: A multiple hearth furnace includes an upright cylindrical furnace housing divided into a plurality of vertically aligned hearth chambers. A cleaning lance inlet port is sealingly connected to the cylindrical furnace housing and radially leads into one of the hearth chambers. A cleaning lance assembly is provided and includes an elongated mount arranged outside the furnace housing and the cleaning lance is slidably mounted on the elongated mount. The cleaning lance includes a cleaning nozzle and can be sealingly introduced through the lance inlet port along a radial trajectory into the hearth chamber by moving it along the elongated mount. The cleaning nozzle is arranged on the cleaning lance, so as to be capable of directing a jet of cleaning fluid onto a rabble arm that is positioned in a cleaning position in the vicinity of the radial trajectory when the cleaning lance is slidably moved along the elongate mount.

Abstract: A multiple hearth furnace comprises at least one cleaning lance inlet port (52, 54) radially leading into one of its hearth chambers (24). A cleaning lance assembly (40′, 40″) includes an elongated mount (42) and at least one cleaning lance (48, 50) slidably mounted on the elongated mount (42). Each cleaning lance (48, 50) is connected to a cleaning fluid distribution system (56) and comprises at least one cleaning nozzle (58, 60). It can be sealingly introduced through the lance inlet port (52, 54) along a radial trajectory into the hearth chamber (24) by moving it along the elongated mount (42). The at least one cleaning nozzle (58, 60) is capable of directing a jet of cleaning fluid onto a rabble arm (34) positioned in a cleaning position in the vicinity of the radial trajectory when the cleaning lance (48, 50) is slidably moved along the elongate mount (42).

Abstract: A rabble arm for a furnace, as e.g. a multiple hearth furnace, comprises an elongated metallic support core (10), at least one rabble tooth having a rabble portion and a fixing portion and fixing means co-operating with the fixing portion for fixing the rabble tooth (14) to the elongated metallic support core. The fixing portion (48) includes a through hole through (50) which said elongated metallic support core axially passes; and the fixing means co-operates with the fixing portion (48) around the through hole for fixing said rabble tooth (14) to said elongated metallic support core (10).

Abstract: A probe includes a probe foot which is suspended on a cable or a chain attached to a winding drum mounted in a sealed casing above the furnace and which communicates with the interior of the latter via a vertical sleeve passing through the upper wall of the furnace, an electric motor associated with a reducer for actuating the winding drum, and a device for detecting the unwinding and winding up of the winding drum in order to control the speed and torque of the motor. The motor is a servomotor, the speed and torque of which are controlled automatically as a function of the detection device by comparison of the actual speed of the motor with data of desired values dependent on the position of the probe foot.

Abstract: A tuyere stock removal device is presented which is particularly well suited for use in conjunction with those types of shaft furnaces having a hot air, closed circuit pipe line which runs a circular course around the bosh. The tuyere stock removal device is suspended by means of rollers on rails and forms an integrated mechanical unit with the hot air, closed circuit pipe line. The present invention will perform all of the handling operations necessary for the dismantling and reinstallation of the blast nozzle and pipe bend as well as the tuyere and any slanting down pipe associated therewith.

Abstract: Multi-path rotatable fluid couplings are formed from modular elements so as to have one, two or three axes about which relative rotation of supply and discharge conduits may occur. These modular elements may be employed in an articulated delivery system for multiple fluids wherein, for example, six pivot axes are provided through a combination of two or more couplings with interconnecting rigid conduits.