Quick change blow lance

Details Quick change blow lance Quick change blow lance

1999-11-18

2001-05-01

Kastler, Scott (Department: 1742)

Metallurgical apparatus

Means for melting or vaporizing metal or treating liquefied...

By means introducing treating material

Reexamination Certificate

active

06224821

ABSTRACT:

The present invention is concerned with a blow lance of the type used to convert molten iron to steel by blowing oxygen into a converter vessel. In particular the present invention concerns the provision of a locking mechanism for use with the quick change lance described in detail in the applicant's co-pending patent publications GB9802609.9 (GB-A-2321952) and PCT/GB98/00376.
In order to expedite the replacement of a lance exhausted by use during steel conversion the aforementioned patent publications disclose a blow lance consisting of a head and a lance body. The heads is in the form of a socket, the upper end of the lance body is in the form of a plug to be plugged into the socket.
The lance body consists of an oxygen pipe surrounded by a water cooling jacket and weighs about five tones operating with the water jacket filled and about three tones dry. It is essential that no water enters the steel conversion vessel or a large explosion could occur. Consequently the cooling jacket consists of a delivery passage adjacent the oxygen pipe and a return passage to return coolant water from the tip of the lance to the head. More than one oxygen blow pipe may be required. The plug portion on the lance body includes sealing surfaces which cooperate with sealing surfaces in the socket so that oxygen ports and coolant delivery and recovery ports in the head communicate with the oxygen pipe and the cooling jacket. The isolation of the coolant and oxygen passages in the blow lance disclosed in GB-A-2321952, relies on O-ring seals and the metal sealing surfaces of the head socket and lance plug are not in direct contact.
During operation oxygen and coolant are delivered to the lance body through the head under great pressure. The pressures act on the horizontal surface of the lance creating forces acting along the vertical axis which tend to separate the lance body from the head. These forces combined with the deed weight of the lance body and any vibration in operation must be locked by a locking mechanism between the head and the lance body.
Known prior art blow lances include that disclosed in PCT/EP96/04693 (WO 9717474) of Thyssen where the blow lance is locked in place by means of hooks
51
which swing into position to engage trunnion pins
52
which project from a collar
53
fastened encircling the lance body
1
.
The present invention aims to provide a reliable and durable locking mechanism for the blow lance disclosed in GB-A-2321952.
According to the present invention there is provided a quick change blow lance comprising:
a head and lance body,
a socket formed in the head,
a plug part formed on the top of the lance body,
whereby axial insertion of the plug part in the socket effects sealed communication of oxygen and coolant passages in the head and the lance body,
a locking mechanism to lock the plug in the socket and to release the plug from the socket when required, said locking mechanism having,
a projection extending from a mouth of the socket towards the axis and mounted for rotation about the axis between a loose position and a locking position and,
a flange extending radially from the lance body beneath the plug arranged so that the flange can pass the projection, in the loose position, during insertion of the plug in the socket and such that rotation of the projection to the locking position causes the flange to engage the projection to prevent separation of the plug and socket.
In use the head is supported on a gantry with the mouth of the socket pointing down. The projection is preferably one of several each separated from the adjacent projection by a circumferentially extending space and supported by a head ring rotatably mounted at the mouth of the socket. The head ring is preferably biased to rotate to the locking position by spring means, for example a coil spring, air spring or other resilient means. The flange will preferably be one of several each circumferentially spaced from the adjacent flange by a gap through which a projection may pass vertically.
Preferably stops are provided to prevent excess rotation of the head ring beyond either the locking position or the loose position.
In a preferred form of the invention the ring is also urged towards the locking position by an extensible ram. The ram is preferably hydraulic and may draw pressure from the coolant water supply via an hydraulic circuit. Alternatively a totally separate pressure source may be used such as pneumatic pressure from air or nitrogen.


REFERENCES:
patent: 4732370 (1988-03-01), Berry et al.
patent: 0545142 A1 (1992-11-01), None
patent: 1002880 A1 (2000-05-01), None
patent: 2321952 (1998-08-01), None
patent: WO 97/17474 (1997-05-01), None

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