Device for handling the various components of an installation for the injection of pre-heated air into a shaft furnace

Abstract

Abstract The manipulation of components of a fluid transmission system, particularly portions of a conduit through which heated gas is delivered to a blast furnace is facilitated by the use of a self-propelled vehicle having mounted thereon a component support mechanism. The vehicle and component support mechanism cooperate to define a pair of displaced vertical pivotal axes whereby the component support mechanism can be readily maneuvered into engagement with the conduit portion to be manipulated. The apparatus is further characterized by a lifting arm assembly which enables the component support mechanism to be raised and lowered without changing the orientation of a supported conduit portion. The present invention relates to a device for handling the various components of an installation for the injection of pre-heated air into a shaft furnace. The invention likewise relates to a multi-purpose self-propelling carriage equipped with a device of this kind. It is known that blast furnaces are fed, via a set of tuyeres which extend through the wall of the furnace, with heated air, known as hot blast, which may be enriched with oxygen. This hot air is introduced through a collecting pipe positioned around the furnace and is distributed in each of the tuyeres by means of separate distributors, known as blast pipes. These blast pipes have a descending part, inclined at a slight angle and incuding compensators to allow for thermal expansions, a substantially horizontal part, known as the nozzle which is applied against the tyere, and an elbow which connects the descending part to the nozzle via flanges. In most furnaces all the tuyeres are situated on the same level and evenly distributed over the entire periphery of the furnace. Certain types of furnace, however, particularly those intended for the treatment of iron ore known as "minette", have two sets of tuyeres at different levels. In most cases there are only half as many tuyeres in the upper row as in the lower. In this case the blast pipes serving the tuyeres of the upper level have descending parts which are shorter than those of the lower blast pipes. On the other hand, the horizontal portion of the upper blast pipes, also known as the auxiliary blast pipes, is generally longer than that of the lower blast pipes, in order to render these blast pipes accessible. The fact is that the gap between the lower blast pipes impede access to the auxiliary blast pipes if these latter are entirely positioned between the wall of the furnace and the lower blast pipes. This is why the horizontal portion of the auxiliary blast pipes is lengthened by means of a crosspiece and the lower part of these auxiliary blast pipes is slightly offset in the radial direction in relation to the descending parts of the main blast pipes. To render the tuyeres accessible, particularly in order to dismantle them, the lower part of the blast pipes first has to be removed, this lower part consisting of the elbow, the nozzle and possibly the crosspiece. This lower part is generally removed all in one piece by loosening the flanges between the elbow and the inclined descending part of the blast pipe. These operations of dismantling, transporting, positioning and reassembling the blast pipe units have previously been carried out with the use of a self-propelling carriage, generally consisting of a fork elevator. A carriage of this kind requires a small turning circle and ample maneuverability, so that the platform provided for this purpose can be made to the smallest possible width. In this context, it should be possible, in particular, to position this carriage on the platform in such a way that it is aligned with the horizontal part of each blast pipe. A carriage for use in the assembly and disassembly of blast pipe units must also enable the lower part of each blast nozzle to be dismantled and re-assembled regardless of the position and angle of inclination the part occupies as a result of thermally induced expansions and deformations. A carriage of the type being discussed must also be so designed that it can be maneuvered rapidly and controlled with ease and above all in such a way as to satisfy all the safety requirements dictated by the operating environment. Even if the carriages hitherto used fulfil most of these conditions to a sufficient extent for medium-size blast furnaces, they are proving less and less satisfactory as the dimensions of the blast pipes increase as a result of the requirements arising out of the progress achieved in modern blast furnace construction. One of the main difficulties being encountered at the present time is due to the fact that, in the transport of the assembly consisting of elbow and nozzle, the centre of gravity of the complete unit formed by the carriage and its load is displaced by the load overhanging the fork of the carriage. In order to ensure that the centre of gravity will not move to a point beyond the wheels of the carriage, so that the latter will not tilt, the carriage has to be made sufficiently heavy or provided with counterweights. These measures obviously have to be taken at the cost of the performance of the carriage, particularly at the cost of the desired maneuverability and space-saving construction. These drawbacks become still more serious in the case of a furnace with two rows of tuyeres, the upper blast pipes forming a much longer load to be dismantled and supported on the carriage so that the known types of carriage may even fail to perform their function altogether. These known carriages are, moreover, of no utility for dismantling and reassembling other components of an installation for the injection of pre-heated air into a shaft furnace such as the tuyeres or the descending sections of the feed lines connecting the circular pipe to the blast pipe elbow sections. The previously available carriages were at most suitable only for the transport of these components. However for dismantling and reassembling said components one has to resort to workmen or special single-purpose appliances. SUMMARY OF THE INVENTION The purpose of the present invention is to provide improved apparatus for handling the components of a gas transmission and/or injection system, and a carriage equipped with this apparatus satisfying the most exacting demands as regards maneuverability, reliability and safety and proving suitable both for the replacement of all types of lower and upper blast pipe component, where necessary, and for other purposes, i.e. capable of acting as a mechanical shovel. According to the present invention there is provided a device for handling the various components of an installation for the injection of pre-heated air into a shaft furnace, said device being designed to be temporarily combined by means of a lifting arm with a control apparatus known per se, and being pivotable about a first vertical axis while the assembly consisting of the lifting arm and the handling device is pivotable about a second vertical axis distinct from the first. In one preferred version the second vertical pivot axis is defined by a removable hinge connecting the lifting arm to the control apparatus. The handling device may also be equipped with wheels and be designed to form the fore-carriage of the control apparatus which forms the hind-carriage. The combination of the movements rendered possible by the two vertical swivel axes enables the handling device to be accurately aligned with the axis of the tuyere of the blast furnace, even if the axis of the control apparatus is offset or inclined in relation to that of the tuyere. This facilitates the manipulation of the carriage, in view of the usual comparative shortage of space available for this purpose. p According to a further embodiment of the invention there is provided a set of adapters designed to be temporarily associated with the said handling device on the one hand, and with each of the various components of the device for the injection of pre-heated air, on the other. These adapters provide a means of dismantling and reassembling and also of transporting the descending part of the blast pipe, as well as the tuyere and even the assembly consisting of tuyere and nozzle in cases in which these two elements are integral with each other. The invention also covers a multi-purpose self-propelling carriage, particularly for the handling of components of an installation for the injection of pre-heated air into a shaft furnace, comprising a chassis mounted on wheels and designed to be combined with each of the elements of a set of interchangeable working tools by means of a removable hinge providing a means of adjusting the orientation of the tool in relation to the chassis, characterized by the fact that at least one of the tools consists of a device such as defined aove and that the second swivel axis of the working tool is formed by the swivel axis of the said hinge. The handling device or its adapter preferably comprises means for securing a component of the installation to the carriage. These means may consist of two parallel arms mounted on the handling device and capable of pivoting about a substantially horizontal axis and by a pin designed to interact with the holes in the said arm and an oblong hole in a bracket provided for this purpose on the component. According to a further embodiment of the invention the handling device can be associated with a pneumatic or hydraulic tool for releasing the tuyere.

Inventors

• 👤 Pierre Mailliet

Bibliographic Details