Improved Means for Temporarily Remedying Defects in the Tubes of Multitube Boilers.
Year: 1893

page_text: Date of Application, 21st Nov., 1893
Complete Specification Left, 20th Aug., 1894-Accepted, 22nd Sept., 1894
Improved Means for Temporarily Remedying Defects in the Tubes
of Multitube Boilers.
I, NORMAN PIRRIE, of 48, Westmoreland Road, Newcastle-on-Tyne, in the
County of Northumberland, Engineer, do hereby declare the nature of this
invention to be as follows:-
or
"
This invention relates to improved means whereby the tubes of either "fire-tube'
"water-tube" boilers may on becoming defective be temporarily repaired and
rendered serviceable.
In the event of a fire-tube becoming defective, it is usual to plug the tube at
each end. This reduces the tube area, and so diminishes the draught. In a marine
boiler, it is moreover necessary to draw the fire before access can be had to the
combustion-chamber end of the tube.
The objects of the present invention are to enable temporary repairs to be effected
in a boiler of the ordinary marine or "return-tube" type without access being
necessarily bad to the combustion-chamber and without diminishing the tube area.
to any appreciable extent.
In carrying out my invention, I place within the damaged or defective tube
another tube furnished at each end with a copper or other soft metal packing ring.
The inner or lining tube is expanded at the outer or smoke-box end in the ordinary
way; the opposite or combustion-chamber extremity of the tube being also
expanded by means of a suitable tool. That end of the tube is preferably formed
with a contracted neck or annular groove in which the copper or other packing
ring lies, the action of the expanding tool being applied to this portion of the tube.
The expansion of the tube and packing ring may be effected from the smoke-box
end by means of a mandrel driven longitudinally or rotated as in a "roller" tube-
expauder. The smoke-box end of the lining tube may if preferred be formed with
a similarly contracted neck for the reception of the packing ring at that end; the
two rings being arranged at such a distance apart on the inner tube as to coincide
with the tube-plates. When the ends of tube are expanded, these rings enable the
lining tube to be fitted perfectly joint tight.
According to an alternative mode of carrying out the invention, the annular
groove at either or each end of the lining tube may be formed in the internal
instead of the external surface thereof. Under these circumstances, a ring, which
may be split, is arranged in the groove inside the tube; the expanding tool acting
on the ring and bringing the external bead on the lining tube (corresponding with
the internal groove) into joint-tight contact with the old or faulty tube. This
enables the two tubes to he brought metal to metal, reduces the number of joints
and diminishes the risk of leakage.
It will be obvious that, in water-tube boilers, the heating tubes may, upon
becoming defective, be rendered serviceable in a substantially similar manner; the
front covers being removed from the terminal passages, and an inner or lining
tube inserted and set joint-tight at each end, in either of the modes hereinbefore
described.
T
1
2000

page_text: Improved Means for Temporarily Remedying Defects in the Tubes
of Multitube Boilers.
I, NORMAN PIRRIE, of 48, Westmoreland Road, Newcastle-on-Tyne, in the
County of Northumberland, Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention relates to improved means whereby the tubes of either "fire-tube"
or "water-tube boilers may on becoming defective be temporarily repaired and
rendered serviceable.
In the event of a fire-tube becoming defective, it is usual to plug the tube at
each end. This reduces the tube area, and so diminishes the draught. In a marine
boiler, it is morcover necessary to draw the fire before access can be had to the
combustion-chamber end of the tube.
The objects of the present invention are to enable temporary repairs to be
effected in a boiler of the ordinary marine or "return-tube" type without access
being necessarily had to the combustion-chamber and without diminishing the tube
area to any appreciable extent.
In the accompanying diagrams,
Fig. 1 is a longitudinal section showing one way of effecting a temporary repair
in a tube of a multitube boiler.
Fig. 2 is a similar view illustrating an alternative mode of temporarily repairing
a faulty tube.
In carrying out my invention in the manner shown in Fig. 1, I place within the
damaged or defective tube A another tube B B¹ furnished at each end with a copper
or other soft metal packing ring C. The inner or lining tube B B' is expanded at
the outer or smoke-box end B in the ordinary way; the opposite or combustion
chamber extremity B₁ of the tube being also expanded by means of a suitable tool.
That end of the tube is preferably formed with a contracted neck b or annular groove
in which the copper er other packing ring C lies, the action of the expanding tool
being applied to this portion of the tube. The expansion of the tube and packing
ring may be effected from the smoke-box end by means of a mandrel driven
longitudinally or rotated as in a "roller" tube-expander. The smoke-box end B
of the lining tube may if preferred be formed with a similarly contracted neck for
the reception of the packing ring at that end; the two rings being arranged at such
a distance apart on the inner tube as to coincide with the tube-plates D. When
the ends of the tube are expanded, these rings enable the lining tube to be fitted
perfectly joint-tight.
According to the alternative mode illustrated in Fig. 2 of carrying out the
invention, the annular groove at either or each end of the lining tube may be formed
in the internal instead of the external surface thereof.
Under these circumstances, a ring C, which may be split, is arranged in the
groove inside the tube; the expanding tool acting on the ring and bringing the
external bead on the lining tube (corresponding with the internal groove) into
joint-tight contact with the old or faulty tube A. This enables the two tubes to be
rought metal to metal, reduces the number of joints, and diminishes the risk of
leakage.
It will be obvious that, in water-tube boilers, the heating tubes may, upon
becoming defective, be rendered serviceable in a substantially similar manner; the
front covers being removed from the terminal passages, and an inner or lining
tube inserted and set joint-tight at each end, in either of the modes hereinbefore
described.

page_text: Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. The improved means whereby defects in the heating tubes of fire-tube or
water-tube boilers may be remedied, access being had to the front tube plate only,
substantially as herein described.
2. For temporarily repairing a faulty fire-tube or water-tube in a multitube boiler,
the employment of an inner or lining tube made joint-tight at each end, substantially
as herein described.
3. In temporarily repairing a faulty fire-tube or water-tube in a multitube boiler
by means of an inner or lining tube, the employment of a ring of copper or other
soft metal placed in an annular groove on the external surface of the inner or lining
tube, the ring lying between the faulty tube and the inner or lining tube, substan-
tially as herein described.
4. In temporarily repairing a faulty fire-tube or water-tube in a multitube boiler
by means of an inner or lining tube, the employment of a ring (which may be split)
lying in an annular groove on the internal surface of the inner or lining tube, the
expanding tool acting on the ring, substantially as and for the purpose herein
described.
described
Dated the 16th day of August 1894.
For the Applicant,
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.