Sulfur gun assembly with rapid service capability

A sulfur gun assembly which may be easily and rapidly disassembled for service. The sulfur gun assembly has an outer casing supported by a furnace wall and the outer casing has a steam outlet and a steam inlet. An inner casing is coaxially held in the outer casing and sealed to the outer casing to provide a steam type annular space. A sulfur gun slides in and out of the inner casing and may be screwed in place in the inner casing. In the event of the necessity of service the sulfur gun may be unscrewed and pulled out of the inner casing without the necessity of removing either the outer or inner casing. This greatly reduces the time for gun removal and also reduces the weight of the removed parts.

BACKGROUND OF THE INVENTION 
The field of the invention is sulfur burning guns and the invention relates 
more particularly to the service of sulfur burning guns. A nozzle for a 
sulfur burning gun is shown in applicant's U.S. Pat. No. 4,154,399, the 
disclosure of which patent is incorporated into the present application by 
reference. Sulfur guns of the type shown in the present application have 
been in operation since the 1920s. They atomize molten sulfur in a furnace 
causing the sulfur to burn and the resulting gas is dissolved in water to 
make sulfuric acid. The design of the sulfur gun has been improved by the 
addition of a steam jacket for cooling the gun. The capacity of such guns 
has also been increased and the net result is that the modern guns can 
weigh 160 to 170 lbs. per unit. The most common types of sulfur gun 
problems are due to nozzle or tip failure or simply plugging and in all of 
these cases the gun must be removed so that the nozzle can be serviced. In 
the case of the conventional 160 lb. gun which is also very hot, this 
removal job is difficult and somewhat dangerous. A typical fast 
replacement of a hot conventional sulfur gun will keep the sulfur plant 
off line for about 11/2 hours, normally using three men for the job. If 
the sulfur plant is a 2000 ton per day plant, the cost of sulfur gun 
servicing is about 125 tons of sulfuric acid. Many times the plant is also 
used to supply steam to a turbo generator which in turn also has to be 
shut down during service because of the lack of steam production. Thus, 
the cost of sulfur gun service is substantial. 
BRIEF SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a sulfur gun assembly 
which may be easily and safely serviced. 
The present invention is for a sulfur gun assembly which may be easily and 
rapidly disassembled for service. The assembly has an outer casing 
supported by a furnace wall in a generally horizontal manner. The outer 
casing has a furnace end and an exterior end and has a steam inlet and a 
steam outlet for cooling the sulfur gun during use. An inner casing is 
supported coaxially in the outer casing and provides a steam type annular 
space between the inner and outer casing for the passage of cooling steam. 
A sulfur gun is slidably inserted into the inner casing and affixed at the 
exterior end. When service is necessary, the sulfur gun is merely 
disconnected at the external end and slid out for service. The gun itself 
weighs only about 20 lbs. and is easily handled by a single worker. 
Preferably the inner casing has reduced diameters at both ends so that the 
gun can more easily be slid in and out. Preferably the sulfur gun is 
threadably secured at the external end and locked in place by a lock nut.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The sulfur gun assembly of the present invention is shown in cross 
sectional view in FIG. 1 and indicated generally by reference character 
10. The sulfur gun assembly is supported by a furnace wall 11 and the gun 
has an outer casing 12, having a furnace end 13 and an exterior end 14, A 
cooling steam inlet 15 and a cooling steam outlet 16 combine with a 
longitudinal baffle 17 shown in FIG. 2 and a pair of restrictor plates 18 
and 19 shown in FIG. 3 to cause the steam to flow outwardly and back 
within outer casing 12. More specifically, steam enters inlet 15 and 
travels outwardly along the gun in the upper half annular space as shown 
in FIG. 2. It then passes through the upper gap between plates 18 and 19. 
The longitudinal baffles do not extend past plates 18 and 19 so the steam 
reverses direction and begins its return by passing through the lower gap 
between plates 18 and 19 and exits cooling steam outlet 16. Thus, the 
outgoing steam does not mix with the incoming steam. 
An inner casing 20 is supported coaxially with reference to the sulfur gun 
longitudinal axis 21 as is outer casing 12. Inner casing 20 has a furnace 
end 22 and an exterior end 23. The inner casing is sealed to the outer 
casing at the outer end by a portion of pipe cap 24. A sulfur gun 25 has 
nozzle end 26 and an exterior end 27. The nozzle end has an expanded 
portion 28 which slides within a reduced portion 29 of inner casing 20. 
The difference between the outside diameter of the expanded portion 28 and 
the inside diameter of reduced portion 29 is about 1/16". This provides a 
sufficiently tight fit and yet permits the sulfur gun 25 to be easily slid 
in and out of the inner casing 20. Inner casing 20 also has a reduced 
portion 30 near its exterior end which facilitates the entrance and exit 
of steam. 
Sulfur gun 25 is secured within the gun assembly by a threaded spacer 31 
having a tapered inner end screwed into threads 32 near the exterior end 
23 of inner casing 20. A lock nut 33 and a gasket 34 help to secure the 
gun in place. A flange 35 is secured to the exterior end 27 of the sulfur 
gun which is used to affix the source of molten sulfur to the sulfur gun 
in a conventional manner. 
The prior art sulfur gun is shown in FIG. 5. In order to be serviced the 
entire assembly 36 must be removed from the furnace. Next the nozzle must 
be cut away from the base of the assembly and the gun flange bored to pull 
the nozzle out. This also involves breaking two 1/2" to 3/4" steam pipe 
unions; eight 7/8" bolts; four 5/8" bolts and then removal of the sulfur 
gun from the furnace This job requires about 11/2 hrs using three men. The 
removed assembly weighs about 170 lbs. In contrast the removal of the 
sulfur gun for service of the gun of the present invention is shown in 
FIG. 4 where all that is required is the removal of the bolts (not shown) 
from flange 35 and the unscrewing of threaded spacer 31 from threads 32. 
The gun portion then can simply be pulled out and serviced or replaced. 
The removed gun portion weighs only about 20 lbs. This simplified job 
takes only about 1/2 hr. and requires only one man although a second man 
is always appropriate for safety purposes. 
The result is a sulfur gun of high capacity which nonetheless may be easily 
serviced. It is believed that this new design will greatly improve the 
efficiency of a plant which requires sulfur gun service. 
Typical sizes of the elements of the assembly include a 4" outer casing, a 
21/2" inner casing at the reduced ends with a 3" inner casing through most 
of the length of the gun. The gun itself has a 1" sulfur line and the 
sulfur nozzle is enlarged to provide a 1/16" clearance between the reduced 
end of the inner casing and the outside diameter of the nozzle portion of 
the gun. The openings in the restrictor plate between plates 18 and 19 are 
preferably about a 20.degree. inlet at the top and a 55.degree. outlet at 
the bottom. The assembly typically extends 6 feet inside furnace wall 11 
and about 1 foot external furnace wall 11. 
The present embodiments of this invention are thus to be considered in all 
respects as illustrative and not restrictive; the scope of the invention 
being indicated by the appended claims rather than by the foregoing 
description. All changes which come within the meaning and range of 
equivalency of the claims are intended to be embraced therein.