Modular lance

Abstract

A modular metalmaking lance having a pre-fabricated "plug-in" lower sections. The plug-in section is preferably of sufficient length to ensure that the joint between a plug-in section and an upper lance section is not in the area of the lance that typically is damaged in refining service. At the same time, the plug-in section is preferably short enough to be transported from an off-site assembly / repair shop to the refining shop via standard-length cargo trucks or truck-trailer rigs used throughout the world.

Description

FIELD OF THE INVENTION[0001] The present invention relates in general to metalmaking processes and equipment and in particular to metalmaking lances for refining metals in a furnace or other vessel.BACKGROUND OF THE INVENTION[0002] A vessel for making metal may assume a variety of forms and designations such as a converter, a Linz-Donawitz (LD) converter, an argon oxygen decarburization (AOD) converter, a basic oxygen furnace (BOF), a basic oxygen process (BOP), an electric arc furnace (EAF), a degasser, and so on. For the purposes of the present disclosure, all metal refining vessels requiring, or benefit by the use of, one or more metalmaking lances shall be hereinafter referred to as a "vessel."[0003] A metalmaking lance is a long tubular apparatus that injects one or more agents into the vessel, frequently at high velocity, to effectuate combustion, scrap melting, slag treatment, metal refining and other processes and treatments, hereinafter collectively referred to as "refining...

AI Technical Summary

Benefits of technology

[0017] The plug-in sections preferably include the lance tip subassembly and other agent injection components, all internal piping and all internal seals, and water jacket piping if the lance is of the cooled variety. All pipes of the upper section of the lance will be connected to the top adapter since the upper section and top adapter require less maintenance and repair than the lower section. A plug-in lower lance section is connected to and disconnected from an upper lance section at a single joint, which acts may be quickly and easily performed by relatively unskilled workers. Moreover, the present invention eliminates the need for metal refining plants to maintain expensive on-site lance repair shops and skilled lance repair workers.

Problems solved by technology

This internal expansion capability reduces the likelihood that the internal pipes will become stressed beyond their tensile limit and fail in operation.

Typically, the lower half of the lance is most vulnerable to damage.

However, in certain geographical areas and under certain unusual circumstances in the United States and North America, as well as in many other regions of the world where refining facilities exist, routine transport of the spent lances is not possible due to inadequate road systems, traffic congestion and / or transport restrictions or excessive hauling distances.

Outside of the North American region, for example, it is generally not possible to transport lances greater than about 13.6 meters in length.

All components, spare parts and / or raw materials must be protected from harmful contamination, which may lead to safety or operation problems when the repaired lance is reused.

Because of the foregoing, in-house lance repair is generally more costly than contracted-out repair.

In addition, maintenance personnel who could otherwise be employed more effectively elsewhere in the refining plant are tied up for extended periods of time in duties associated with lance repair.

Moreover, in-house repaired lances are often of inferior quality compared to those repaired by specially-qualified and dedicated lance repair personnel.

And, under certain unusual instances at refining facilities that normally outsources its lance repairs, the facilities must bear the considerable expense of having outside repair specialists bring equipment and supplies to the facility to perform lance repair on-site.

As a result, for lances that might be of acceptable length for transport in much of the United States and the North American region but not elsewhere, merely disconnecting such lances from their top adapters does not reduce the length of the lances whereby they may be transported via standard-length cargo trucks or truck-trailer rigs used throughout the world.

Thus, U.S. Pat. No. 6,212,218 also does nothing to render an oversized lance transportable in geographic areas that accommodate only standard-length cargo trucks or truck-trailer rigs.

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