Improvements in Compound, Metal Tubes.
Year: 1899

page_text: Date of Application, 4th July 1899 Accepted, 5th Aug.,
1899
Improvements in Compound, Metal Tubes.
I, GEORGE HARKER EVERSON, Newark, Licking County, Ohio, U.S.A., Manu-
facturer, 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 improvements in compound' metal tubes for steam
boilers, feed water heaters, hot water heaters, and other apparatus of like character,
and has particular reference to the provision of a compound tube, one metal of
which is calculated to resist the action of hot water and impurities in the water
which, otherwise, would attack the other metal. and also to protect said other
metal from incrustation due to the action of limo, magnesia &c. In water heat-
ing and steam generating apparatus in which single-metal iron or steel tubes are
employed, the water-exposed surfaces of the tubes rapidly deteriorates under the
action of hot water and the impurities therein contained. When lime, magnesia
and other similar matter is present in the water, scale is formed and attracted
to the tube surfaces to which it adhores, and the scale being a non-conductor of
heat the efficiency of the apparatus is impaired and greater consumption of fuel
is necessary to heat the water, or generate steam, as the case may be. These
difficulties are encountered as well in the use of flue tubes as with water tubes,
and the object of the present invention, primarily, is to provide a compound tube
for such use, the water exposed surface of said tube being of a metal, such as
copper, which is not affected by the action of hot water or its contained impurities.
A further object of the invention is to so arrange the protector-metal of the tube
as to form a bushing for the joint between the tube and tube-sheet or boiler-head.
The invention consists in certain novel features of construction, herein after
fully described and claimed, and illustrated by the accompanying drawing in
which;
Figure 1 is a perspective view of the tube. Fig. 2 is an elevation, partly in
section, of three water tubes, illustrating the different steps in securing them to
the head. Fig. 3 is an end view of Fig. 2. Fig. 4 is a view similar to Fig. 2
showing flue tubes. Fig. 5 is an end view of Fig. 4.
Tube A, which may be of iron or steel, is provided with lining B of relatively
thinner metal, and of such kind as will resist the action of hot water and impurities
therein, the preferred metal being copper. The lining or inner tube B is made
somewhat longer than tube A, and adapted to fold backward on the outer surface
thereof, as shown at C. The tube thus formed is inserted in the sheet or boiler
head D as at the top of Figure 2, the backwardly turned portion being longer
than the thickness of head D, with the latter about midway its ends. An
expander, of any suitable form is applied to enlarge the tube end and seal the tube
opening in the head, the tube within the head or on its inner side, being enlarged
to a diameter greater than the tube opening in the head, thereby forming an
annular rib E on the tube. The tube end thus expanded completely fills and seals
the head opening, backwardly turned portion C of the lining or inner tube serving

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as a gasket for the joint, making perfect the joint and seal. Tube end F is then
upset against head D.
In Figs. 4 and 5 a flue tube G is shown, made compound by outer copper cover-
ing or tube H, and being on the outside, is of same length as tube G, and the
compound tube is expanded in making joint with the boiler head as described of
construction of Figs. 2 and 3.
Having now particularly described & ascertained the nature of my saiil
invention & in what manner the same is to be performed I declare that what
I claim is
1. A water tube boiler having its iron or steel tube lined with impurities-resist-
ing material, and a protecting covering for the end surfaces of the tubes and for
their joints with the boiler heads, whereby no portions of the iron or steel tubes
are subjected to the action of water and the impurities contained therein.
2. The combination with a boiler head, and a water or flue tube, of a protecting
tube extending from end to end of the latter and completely covering its surface
adjacent the water, the protecting tube also extending into the opening of the
boiler head and forming a gasket for the joint, the compound tube thus formed
being expanded within the head to a greater diameter than the head opening, and
the projecting end of the compound tube upset against the head.
3. As a new article of manufacture, a compound boiler tube consisting of outer
tube A and inner tube B longer than tube A, the extended portion of tube B
being turned back over the outer surface of tube A for the purpose described.
4. The combination with a boiler having a tube opening, and tube A, of pro-
tecting tube B within tube A and longer than the latter, the extended portion of
tube B being turned backward over the outer surface of tube A to form a scaling
gasket for the joint between the tube and head.
Dated this 22nd day of June 1899.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, Agents.