WO1988000680A1

WO1988000680A1 - Refractory gunning apparatus

Info

Publication number: WO1988000680A1
Application number: PCT/GB1987/000493
Authority: WO
Inventors: Eustace Peter Barnes; Douglas Eric Skeldon
Original assignee: Morgan Refractories Limited
Priority date: 1986-07-11
Filing date: 1987-07-13
Publication date: 1988-01-28
Also published as: AU7692487A; GB2192350A; GB8616911D0; GB8703361D0

Abstract

Gunning apparatus (10) to be lowered as a unit into a refractory vessel has a conduit (20) for refractory material depending from a housing (12), the conduit being rotatable relative to the housing about a generally vertical axis and the housing containing means (26, 28) to oscillate the conduit about said axis, a spray nozzle (34) extending sideways from the conduit and immediately under the housing and a mixer head (32) to mix and supply a gunning mixture of refractory material and water to the spray nozzle; in a preferred embodiment the mixer head is arranged immediately upstream of the spray nozzle and a water-cooled video camera is mounted under the housing, water supplied to the mixer head being arranged to first flow through the video camera jacket (36) for cooling.

Description

REFRACTORY GUNNING APPARATUS

This invention relates to refractory gunning apparatu to be lowered into a refractory vessel, such as a steel making furnace, and spray a refractory/water gunning mixture onto the walls thereof to form or repair the vessel lining. The invention particularly relates to apparatus suitable for so-called "hot gunning"; i.e. the repair of linings whilst the furnace is still hot.

Known refractory gunning apparatus is described in United Kingdom Patent Specification No. 1422749, which discloses an elongate, axially extending gunning conduit provided at one end with a nozzle, extending vertically •upwards through a control box to a swivel coupling inside the control box, wherein a mixing head is connected to the coupling. The control box also houses an oscillatory drive for the gunning conduit. The gunning apparatus is shown with the control box above the furnace and only the gunning conduit and the nozzle extending down into the furnace. Clearly such a long gunning conduit is difficul to control, resulting in an uneven sprayed lining. United Kingdom Patent Specification No. 1592944 discloses a stationary housing located above a furnace and a rotatable nozzle pipe that is axially movable relative to the housing, and into and out of the furnace.

It is an object of the present invention to provide refractory gunning apparatus which is designed to be lowered as a unit into a furnace. According to the present invention, refractory gunning apparatus to be lowered as a unit into a refractory vessel comprises: a conduit for refractory material depending from a housing, the conduit being a rotatable relative to the housing about a generally vertical axis and the housing containing means to oscillate the conduit about the said axis, a spray nozzle extending sideways from the conduit and immediately under the housing, and a mixer head to mix and supply a gunning mixture of refractory material and water to the spray nozzle. Such apparatus is compact and, the nozzle being close to the housing, enables the mass and inertia of the housing to stabilise the oscillation of the nozzle and thus improve the spray pattern. Additionally, the distance through which the mixed refractory and water gunning mixture has to flow to the nozzle is much reduced.

In an embodiment of the invention, the mixer head is positioned between the spray nozzle and the conduit and a flexible water supply is connected to the mixer head. Such an arrangement eliminates the need for a swivel joint in the housing and further reduces the flow distance of the gunning mixture.

European Patent Specification No. 0039212 discloses a remote control gunning apparatus with a water-jacketed television camera lowered into a furnace along with a gunning conduit. Conductors 56 and 58 supply cooling water to and from the camera water jacket.

In a preferred embodiment of the present invention, a video camera is provided, the camera having a water jacket connected to the flexible water supply with a further water connection to the mixer head; whereby water for the mixer head is first used to cool the video camera. By this means the need for a return path for video camera coolant is eliminated.

In a further embodiment of the present invention, the conduit os-cillating means comprises a reversible m tor connected by a drive to rotate the conduit in opposite directions, limit switches operative between the conduit and the housing and arranged to switch the motor to control the oscillatory rotation of the conduit and a lost-motion device to activate the limit switches to control rotation of the spray nozzle through 360° or more.

The above and other features of the present invention are illustrated, by way of example, in the drawings, wherein :-

Fig. 1 is a part-sectioned side elevation of gunning apparatus in accordance with the present invention;

Fig. 2 is a detailed view in the direction of arrow X of Fig. 1; Fig. 3 is a detailed view in the direction of arrow Y of Fig. 1; and

Fig. 4 is a perspective view of a limit switch oscillatory control device.

As shown by Figs. 1-3, gunning apparatus 10 has a

1 generally cylindrical housing 12 provided at its upper periphery with three equi-spaced eyebolts 14 by which the whole apparatus is suspended. Housing 12 has a refractory lining 16 and a removable stand 18. Stand 18 being attached to the housing by pins so that, in use, the housing can be lifted by a hoist attached to eyebolts 14, the pins removed to leave the base behind and leave ^• unobstructed the nderparts of the housing.

A pipe or conduit 20 passes axially through the housing and is journalled in housing top plate 22 and bottom plate 24 to be rotatable relative to the housing and about its vertical axis. A reversible electric motor 26 is mounted within the housing to rotate the conduit 20 by means of a chain and sprocket drive 28.

Conduit 20 depends below the housing and has a T-piece 30 extending sideways immediately beneath the housing bottom plate 24. Serially connected to the side arm of T-piece 30 are a mixer head 32 and a spray nozzle 34. The bottom of conduit 20 is closed by a jacket 36 for a video camera.

The upper plate of housing 12 receives a feed pipe 38 for refractory material (usually a fluidised dry powder conveyed by air flow), a feed pipe 40 for water and a combined air and electrical cable feed 42 (supplying electric power to motor 26 and electrical connections to the video camera, the air supply cooling the electrical cable) .

Water passes down a pipe 44 within the housing to a flexible pipe connection 46 to the video camera water jacket 36 and by a further pipe 48 to the mixer head 32, wherein water is injected into the stream of refractory material to form a gunning mixture that is sprayed from the nozzle 34. The water supply to the mixer head is thus

_* used to cool the video camera. Lights 50 are positioned to either side of the video camera to illuminate the area being gunned.

Further connections are provided between the housing and the video camera jacket 36 for connections to the camera, electrical power to the lights and air to cool and keep clear a window 50 in the jacket for the camera.

As shown by Fig. 4, electrical limit switches 54, 56 are mounted on bottom plate 24 and are employed in known manner to control the oscillatory rotation imparted to conduit 20 by electric motor 26. The limit switches are activated by means of a finger 58 which projects radially outwardly from a collar 60 surrounding and rotatable with respect to the conduit 20. A lost-motion device is formed by peripheral slots 62 in collar 60 that co-operate with pegs 64 fixed to conduit 20. The action of the lost-motion device is to compensate for the side-by-side arrangement of the limit switches 54 and 56 to ensure that conduit 20 and hence nozzle 32 is rotated through at least the 360°. If slot 62 is of a length to subtend an angle greater than that subtended between the limit switches then the ends of the rotational traverse of the nozzle 32 will overlap.

Claims

1. Refractory gunning apparatus to be lowered as a unit into a refractory vessel and comprising a conduit (20) for refractory material depending from a housing (12), the conduit being rotatable relative to the housing about a generally vertical axis and the housing containing means (26, 28) to oscillate the conduit about said axis, a spray nozzle (34) extending sideways from the conduit and a mixer head (32) to mix and supply a gunning mixture of refractory and water to the spray nozzle characterised in that the spray nozzle (34) is located immediately under the housing (20).

2. Gunning apparatus as claimed in claim 1 and further characterised in that the mixer head (32) is positioned between the spray head (34) and the conduit (20) and a flexible water supply (46) is connected to the mixer head.

3. Gunning apparatus as claimed in claim 2 and further characterised in that a video camera is provided, the carrier having a water jacket (36) connected to the water supply (46) with a further water connection (48) to the mixer head (32); whereby water for the mixer head is first used to cool the video camera.

4. Gunning apparatus as claimed in any of claims 1 to 3 and further characterised in that the conduit oscillator means comprise a reversible motor (26) connected by a drive (28) to rotate the conduit (20) in opposite directions, limit switches (54, 56) operative between the conduit and the housing (12) and arranged to switch the motor to control the oscillatory rotation of the conduit and a lost-motion device (60, 62, 64) to actuate the limit switches to control rotation of the spray nozzle (34) through 360° or more.