Apparatus For Spraying Refractory Lining

Abstract

A lining gun for spraying refractory lining on the interior of ladles and the like which includes two elongate concentrically disposed conduits through which dry refractory material and water are respectively passed at one end and sprayed through mixing nozzles at the opposite end. Each conduit includes a rotary coupling immediate its length and cooperates with a motor driven ring and pinion assembly which rotates the lower portion of the apparatus including the nozzles for circular spraying.

Description

BACKGROUND OF INVENTION

In the iron and steel industry, such deep walled refractory bodies as ladles, soaking pits and furnaces are subjected to extremely high temperatures over long periods of time. Such high temperatures cause deterioration of the refractory linings of the bodies. After the lining has deteriorated to a certain point, the lining must be replaced or repaired before the ladle, etc. can be further used.

The interior surface of the ladles can be repaired in a number of different ways. One common repair which has come into common practice is to spray a protective coating of refractory material onto the interior of the ladle.

Refractory spraying apparatus for ladles and the like which are available today are all essentially hand operated devices. A man is required to enter the ladle and to hand spray the refractory material about the interior. Hand spraying of the ladles is an extremely time consuming job. Additionally, the quality of the job accomplished is only as good as the skill of the laborer.

A further problem encountered in hand spraying of ladles is the cooling time required before a workman can enter the ladle or furnace. For example, a ladle of ordinary and common size which has just been taken out of use will require between six to twelve hours to cool before a workman can enter the ladle to spray a new lining. The turn around time between cooling, spraying and drying of a ladle can be extremely detrimental to production rates in a steel mill and costly as well.

There is a requirement in the industry for a ladle spraying apparatus which will operate automatically to deposit the lining in a controlled manner and also one which can spray on the lining immediately or shortly after the ladle is taken out of service without having to wait for the ladle to cool and be hand sprayed.

OBJECTS AND SUMMARY OF INVENTION

It is the object of the present invention to provide a lining gun for spraying a refractory lining on the interior of ladles and the like which operates automatically and in a controlled manner in depositing the lining and also which may be employed for hot replacement of the sprayed refractory material within a hot ladle.

The foregoing object is carried out by the lining gun of the present invention by means of two elongate conduits, one of which is disposed concentric within the other. The first and outer conduit includes an entrance end through which dry refractory material is air conveyed to opposed mixing nozzles at the opposite end of the conduit. The second and inside conduit includes an entrance end through which a wetting agent for the refractory material is passed and terminates at its opposite end in communication with the mixing nozzle wherein the wetting agent is mixed with the dry refractory material to provide the wetted material which is sprayed.

The inner and outer conduits each include rotary coupling means which permit rotation of the lower portions of each of the conduits attached to the spray nozzles relative to the upper portions thereof. Motor means attached to the upper stationary portion of the outer conduit drives a pinion which in turn drives a ring gear attached to the lower outer conduit to revolve the mixing nozzles.

In a specific embodiment, a stabilizing bearing is journaled upon the lower portion of the outer conduit adjacent the coupling. The stabilizing bearing is secured to a bearing carrier which is rigidly secured to the upper stationary portion of the outer conduit to provide rigidity to the outer conduit across the rotary coupling.

The lining gun includes a carriage assembly at its upper portion by which the entire assembly is suspended within and for axial movement through the interior of the ladle or furnace. The entire assembly is moved axially from the bottom of the ladle toward the top thereof as the spray nozzles are rotated to completely and entirely spray the interior of the ladle or furnace.

Other objects and advantages of the present invention will become apparent to those skilled in the art from the detailed description of the invention which follows taken in conjunction with the drawings.

DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of the entire lining gun of the present invention shown in position in use with a ladle;

FIG. 2 is a side view of the upper portion of the lining gun of the present invention;

FIG. 3 is a side view of the lower portion of the lining gun of the present invention; and

FIG. 4 is a side view partially in section of the details of the flow splitter employed in the lining gun of the present invention.

DETAILED DESCRIPTION OF INVENTION

The gun for spraying refractory lining of the present invention is shown in FIG. 1 in its postion of use. The entire assembly 10 is designed to be suspended above a ladle 14 by means of a crane hook 12 and cable 13 which engage a carriage assembly 11 supporting the remainder of the apparatus.

Generally, the lining apparatus includes an elongate first or outer conduit 15 through which a dry refractory material is air conveyed to a pair of opposed mixing discharge nozzles 17 at the lower end of the conduit. A similar second or inner conduit disposed within the first conduit 15 is connected to a water supply line 9 and extends to the mixing discharge nozzles 17 at which point the water is mixed with the dry refractory material and sprayed from the nozzles.

As will be described in more detail hereinafter, both the inner and outer conduits include rotary couplings which permit the lower ends of the conduits connected to the discharge nozzles 17 to be rotated relative to the top portions of the conduits. These rotary couplings operate in conjunction with a drive mechanism 18 which causes the lower portion of the mechanism, including the nozzles 17, to be rotated while the upper portion of the assembly remains stationary.

During operation, the mixed material is sprayed from the nozzles while the nozzles rotate to present a circular spraying pattern. Simultaneously with the rotation of the nozzles, the entire assembly is slowly raised upwardly through the ladle covering the entire inner surface of the ladle with the refractory material.

The details of the refractory spraying mechanism of the present invention are shown in FIGS. 2-4. The body of the lining gun is formed of a first elongate conduit 15 which extends substantially throughout the entire length of the gun. The upper portion of the first conduit 15 is enclosed by a pipe cap 23 and is secured to a crossbar 19 by means of a U-clamp 20. The cross-bar 19 is, in turn, welded between a pair of vertical support arms 21 which are likewise welded to the main carriage beam. In this manner, the main carriage assembly provides the supporting structure for the first conduit 15 and all of its related plumbing and hardware while the gun is being suspended for use over a ladle.

The outer conduit 15 also includes an entrance port 41 disposed in the upper extremities of the conduit. The entrance port 41 is formed by a pipe welded over an aperture in the side wall of the conduit 15. The port 41 terminates in a suitable pipe coupling 42 which is interconnected with the refractory material supply line 16.

A wear sleeve 43 is positioned around the inner conduit 22 adjacent the discharge end of the port 41. The wear sleeve 43 protects the surface of the inner conduit 22 from the abrading action of the refractory materials passing through the entrance port 41.

The lining gun also includes an inner or second conduit 22. The conduit 22 is disposed within and concentric of the first conduit 15. The upper end of the conduit 22 extends through a sealing packing gland 24 which is fitted into the pipe cap 23.

A rotary coupling 25 is provided and is connected to one end of the inner conduit 22. The opposite end of the rotary coupling is connected through a plumbing tee to a horizontal supply line 26. The supply line 26 is secured in place and against rotation through apertures 28 in the vertical support arms 21 of the carriage assembly.

The lower end of the outer or first conduit 15 terminates in a pipe cap 29 which encloses the bottom end of the conduit. Immediately above the pipe cap 29 are disposed a pair of opposed discharge mixing nozzles 17.

The discharge nozzles 17 include a pair of entrance ports 30 which are suitably welded over cutout openings in the side walls of the first conduit 15. A water flow mixer assembly 31 is threaded onto each of the entrance ports 30. In turn, a discharge nozzle 32 is threaded into the water flow mixer assembly 31.

The lower end of the inner conduit 15 terminates in a flow splitter 33. The flow splitter 33, as may be seen in FIG. 3 and in detail in FIG. 4, is positioned in the lowermost portion of the first conduit 15 and is held in place by abutment with the pipe cap 29.

The flow splitter 33 includes an internal passageway 34 through the body of the flow splitter. The upper end 35 of the passageway is threaded and receives the threaded lower end of the inner conduit 22.

The opposite end of the passageway 36 is formed at a right angle to the axis of the conduit 15 and is likewise threaded to receive a pipe nipple 37 which passes through a suitable aperture in the wall of the outer conduit 15. A plumbing tee 38 is provided on the pipe nipple 37. In a like manner, a pair of flexible hoses 39 are connected to the plumbing tee and to the respective water flow mixer assemblies 31 to complete the flow path through the inner conduit 22.

The flow splitter 33 further includes two opposed faces 40. The opposed faces are turned generally perpendicular to the longitudinal axis of the nozzles 32. The faces converge at a point above the entrance port 30 and flare downwardly and outwardly to a terminal point below the entrance port 30. The flare of the flow splitter serves to evenly deflect the refractory material to the nozzle assemblies.

A further rotary coupling 44 is provided intermediate the ends of the first conduit 15 as may be seen in FIG. 3. The rotary coupling permits the lower portion of the conduit 15 to be rotated while the upper portion thereof is held stationary. The coupling is airtight to prevent escape of material passing through the conduit.

The lower portion of the outer conduit 15 and its included discharge nozzle assembly is driven in a rotary manner by means of a drive assembly 18. The drive assembly 18 includes a pair of opposed stabilizing plates 45 which are suitably welded to the outer surface of the outer conduit 15 at a point immediately above the rotary coupling 44. The lower portions of the stabilizing plates 44 extend downwardly to a point below the rotary coupling 44.

A horizontal bearing carrier plate 46 is provided and includes an aperture within the plate through which the outer conduit 15 extends. Either end of the bearing carrier plate 46 extend outwardly and are interconnected with the lower ends of the stabilizing plates 45. A split journal bearing 47 is positioned around the conduit 15 immediately below the horizontal carrier plate 46. The journal bearing 47 is interconnected to the carrier plate 46 by angle races 48. The arrangement of the stabilizing plates 45, bearing carrier 46 and journal bearing 47 add stability and reinforcement against side loads on the outer conduit 15 across the rotary coupling 44. A ring gear 49 is disposed concentrically around the outer conduit intermediate the rotary coupling 44 and journal bearing 47. The ring gear 49 is secured in place on a flange 50 which is welded to the outer circumference of the conduit 15. A suitable air motor 51 is mounted on one of the stabilizing plates 45. The air motor includes a drive shaft 52 and a pinion 53 for driving the ring gear 49 and consequently revolving the nozzles.

Two flange coupling assemblies 54 and 55 are provided along the length of the outer conduit 15. These coupling assemblies aid in fabrication and assembly of the outer and inner conduits.

In operation, a dry refractory material is air conveyed through the feed line 16 and downwardly through the outer conduit and discharged past the flow mixer assemblies through the discharge nozzles 32. As this is occurring, a suitable wetting agent for the dry refractory material such as water, is passed through the inner conduit 22 to the flow mixer assembly. The water flow mixer assembly 31 includes a plurality of internal orifices around the inner circumference of the mixer assembly which sprays the water into the passing dry refractory material to form a mixed wet spray material.

Once the refractory material has begun discharging, operation of the drive mechanism 18 is initiated to impart rotation to the opposed nozzles. Likewise, the entire assembly will be slowly moved upwardly in the ladle to assure complete coverage of the inner surface of the ladle.

It has been found appropriate to angle the nozzles downwardly at an appropriate angle of six to seven degrees. This angulation helps assure coverage of the bottom and the convergence of the bottom with the walls of the ladle. It has also been found that an appropriate speed of rotation for the nozzles is approximately from one to three revolutions per minute.

From the foregoing description, it will be appreciated that the present invention provides a lining gun which provides for automatic spraying of lining on ladles and the like and also a lining gun which may be used in conjunction with lining of hot ladles.

The lining gun assembly of the present invention has been described in respect to particular embodiments thereof. It will be appreciated, however, to those skilled in the art that modification may be made in the method and apparatus according to the invention without exceeding the ambit of its spirit and scope.

Claims

I claim:

1. A lining gun for spraying a refractory lining on the interior of deep walled refractory bodies such as ladles and the like comprising:

a first elongate conduit having an entrance end through which dry refractory material is air conveyed and terminating at its opposite end in a mixing discharge nozzle through which the refractory material is sprayed;

a second elongate conduit disposed within and concentric of the first conduit and including an entrance end for receiving a wetting agent for the refractory material and terminating at its opposite end in communication with the mixing nozzle;

first and second rotary coupling means connected to the first and second conduits respectively intermediate their entrance ends and the discharge nozzle permitting relative rotary motion between the entrance ends of the conduits and the discharge nozzle; and

drive means for driving the discharge nozzle in a rotary manner whereby the nozzle may be drawn axially through the refractory body as the nozzle is rotated and refractory material sprayed therefrom to uniformly coat the interior surface thereof.

2. The lining gun of claim 1 wherein the mixing discharge nozzle includes two opposed orifices and further including means disposed adjacent each orifice and centrally of the first conduit to divide the flow of dry refractory material equally between each orifice.

3. The lining gun of claim 1 wherein the drive means includes a ring gear carried by the first conduit intermediate the coupling means and the discharge nozzle; motor means carried by the first conduit opposite the coupling means and pinion drive means interconnecting the motor means and the ring gear.

4. The lining gun of claim 3 further including bearing means secured to the first conduit intermediate the coupling means and discharge nozzle and bearing carrier means interconnecting the bearing means and the first conduit at a point opposite the coupling means from the bearing means to maintain alignment of the first conduit across the coupling means.