Conveyors – chutes – skids – guides – and ways – Chutes – Horizontal and vertical swing
Reexamination Certificate
1999-11-12
2001-04-10
Bidwell, James R. (Department: 3651)
Conveyors, chutes, skids, guides, and ways
Chutes
Horizontal and vertical swing
C414S160000, C266S176000
Reexamination Certificate
active
06213275
ABSTRACT:
The present invention relates to a device for distributing materials in bulk with a rotary chute having a variable angle of inclination. It relates more particularly to a device for distributing materials in bulk comprising a chute, a first rotor with a substantially vertical rotation axis, on which the chute is suspended so that it can pivot about a substantially horizontal pivoting axis, and a second rotor, having a rotation axis substantially coaxial with said first rotor.
Such devices for the distribution of materials in bulk are used, for example, in devices for charging shaft furnaces, particularly blast furnaces. The rotary and pivoting chute provides for the distribution of the charge over a charge surface inside the shaft furnace.
In the device described in the preamble, the first rotor essentially rotates the chute about a vertical axis. The second rotor interacts with the chute so as to fix its angle of inclination to the vertical. For this purpose, the second rotor is connected to the chute through a pivoting mechanism converting a variation in angular displacement between the two rotors into a variation in the angle of inclination of the chute in its vertical plane of pivoting.
Different variants have been proposed for the embodiment of this pivoting mechanism, which generates the torque required to pivot the chute about its horizontal pivoting axis and which transmits this torque to the chute.
The patent U.S. Pat. No. 3,766,868 proposes a device of the type described in the preamble in which a linking rod located in the pivoting plane of the chute is coupled at one end to the rear surface of the chute. The other end of this linking rod is guided in a sinusoidal guiding track on the second rotor.
The patent U.S. Pat. No. 3,814,403 proposes a device of the type described in the preamble in which the second rotor comprises an annular gear. The latter, through the intermediary of a first pinion, drives a worm which, through the intermediary of a second pinion, acts on a sector gear fixed laterally on to a suspension journal for the chute.
The document U.S. Pat. No. 4,368,813 proposes a device of the type described in the preamble in which the rotor also comprises an annular gear. The first rotor carries a worm drive. The input shaft of the latter is provided with a pinion which meshes with the annular gear of said second rotor. The output shaft is parallel to the pivoting axis of the chute and is equipped with a crank. A connecting rod. contained in the pivoting plane of the chute, is coupled at one end to the rear surface of the chute and at the other end to the crank.
The document U.S. Pat. No. 4,941,792 proposes two devices of the type described in the preamble. A first embodiment uses a pivoting lever supported by the first rotor so that it can pivot in the pivoting plane of the chute. This pivoting lever is connected to the second rotor by means of a linking rod having ball-and-socket joints. The chute comprises two lateral suspension journals each of which is provided with a crank. A forked linking rod connects the pivoting linking rod to the two cranks on the chute. In the second embodiment the second rotor supports an annular segment gear which cooperates with a sector gear attached to a lateral suspension journal on the chute.
The document U.S. Pat. No. 5,002,806 proposes a device of the type described in the preamble in which the second rotor is connected to a crank attached to a lateral suspension journal on the chute using a linking rod having ball-and-socket joints.
The objective of the present invention is to propose a simple and compact device making it possible to transmit large pivoting torques to the rotary chute. In conformity with the invention, this objective is achieved by a device according to claim
1
.
A device for distributing materials in bulk according to the invention comprises a first rotor and a second rotor having a common substantially vertical rotation axis. Said first rotor carries two suspension bearings, in which a distribution chute is suspended so that it can pivot about a substantially horizontal pivoting axis. The device also comprises a gear transmission, which is also carried by said first rotor. This transmission comprises an input shaft and an output shaft. The input shaft is fitted with a pinion which meshes with an annular gear of said second rotor. The output shaft of the transmission is parallel to the pivoting axis of the chute. According to an important feature of the present invention, the output shaft incorporates two cranks, while the chute is fitted with a pivoting lever at the level of each of its suspension bearings. Each of these two pivoting levers is then connected to one of the two cranks of the gear transmission by means of a connecting rod. A difference between the angular rotational speed of the first rotor and that of the second rotor produces a rotation of the input pinion of the gear transmission about its own axis and hence also a rotation of the two cranks carried by the output shaft of the transmission. These two cranks then symmetrically transmit, through the intermediary of the above-mentioned pair of connecting rods and levers, the pivoting torque to the chute. This makes it possible to transmit large pivoting torques to the rotary chute with a simple and compact device.
Such a distribution device will usually comprise a fixed vertical charging duct positioned so as to pour the material in bulk into the chute. Said first rotor then advantageously comprises a vertical suspension sleeve which surrounds the fixed charging duct and is provided at its lower end with a horizontal flange. The latter carries the bearings for the suspension of the chute and the gear transmission on its upper surface.
The gear transmission is advantageously symmetrical with respect to a symmetry plane of the two suspension bearings. It comprises a worm drive or an equivalent system of gears having an input shaft and an output shaft perpendicular to each other. The worm drive has the particular advantage that it can easily be designed to be self-locking, so that the torque due to the weight of the chute will not be taken up by the second rotor.
When the device according to the invention is installed in a furnace, it will advantageously include a casing provided at its lower end with a fixed screen. This screen is then provided with a circular opening into which a flange of said first rotor is fitted. A gas injection pipe is positioned along said circular opening so as to be able to inject a cooling gas into a hollow space of the flange. A cooling system for the device may also include a cooling circuit positioned in an annular space between said first rotor and the fixed vertical charging duct used to pour the material in bulk into the chute.
REFERENCES:
patent: 4243351 (1981-01-01), Legille et al.
patent: 4368813 (1983-01-01), Mailliet
patent: 4547116 (1985-10-01), Legille et al.
patent: 5273148 (1993-12-01), Lonardi et al.
Cimenti Giovanni
Lonardi Emile
Bidwell James R.
Paul Wurth S.A.
Smith , Gambrell & Russell, LLP
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