Improvements in Steam Generators of the Locomotive Type.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Steam Generators of the Locomotive Type.
I, WALTER MACKERSIE SMITH, of 16, Otterburn Terrace, Jesmond, Newcastle-
on-Tyne, in the County of Northumberland, Engineer, 'do hereby declare the
nature of this invention to be as follows:
-
This invention has for its object improvements in steam generators and consists
in placing any convenient number of tubes in combination with the fire-box
in boilers of the locomotive type. The tubes form a means of connecting the
water space at one point with that at another, the object being to obtain increased
heating surface and a better water circulation.
The water tubes are by preference curved and may connect points on the
same side or on opposite sides. Or they may connect the sides and the ends or
the sides or end with the roof of the fire-box. The fire-box plate or plates may.
be corrugated to receive the tubes or the tubes may be attached to pipes, the
ends of which are in connection with the water-space.
The tubes are detachable and joined to the fire-box plates by suitable couplings;
they can be removed for examination and replaced or new parts substituted.
I do not limit myself to any particular form of coupling. Any of the following
forms of couplings may be used for boilers of the locomotive type or for any
other type of water-tube boiler.
A coupling has a hollow plug tapered and screwed on the outside. The plate
into which the plug is screwed is thickened by drifting a small hole being
first bored. The ends of the tubes are thickened and screwed. The screwed
part on the plug projecting beyond the fire-box plate is made larger in diameter
than the screwed part on the tube. The pitch of the screw is also made greater.
A nut or ferrule having one end screwed to fit the tube; and the other screwed
to fit the plug, is run on to the tube. After the tube is placed in position, the
nut is run forward on to the plug. As the screw on the latter is the coarser,
the end of the tube is drawn into or against the plug-thus forming a steam
tight joint.
The tube ends may be thickened or, by preference, a metal ring may be
screwed or fixed on the tube at either end the metal ring being formed with a
collar to fit a suitable union nut. This nut is screwed at one end to fit a hollow
plug. The plugs are screwed into the fire-box plate or plates; the tubes are
placed in position; the union nut is screwed on to the plug and the tubes are
drawn up to or into the plug.
A nut formed with a cone on one face is passed on to each end of the tube,
then a hollow tapered plug. A ferrule with a cone at one end and screwed at
the other end is then braized or securely fixed on each end of the tube.
The
tube is placed in position and the hollow tapered plug is then screwed into the
fire box plate. The nut with the coned face is screwed on to the ferrule on
the tube ends until the cone at its outer end bears against the hollow plug and
the cone on the nut beds on the inner end of the plug.

page_text: A hollow plug is passed on to each end of the tube, and a screwed ferrule
with a cone formed on the end is then fixed on each end of the tube. The tube
is placed in position and the plug is screwed into the plate forming the water
space until the end of the plug beds itself on the cone formed on the ferrule
fixed on the ends of the tube.
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A nut is passed on to each end of the tube and then a wedge shaped ring.
The ends of the tube are then expanded; a tapered hollow plug is screwed in
the fire-box plate; the tube is placed in position; the hollow plug is screwed
inside, to fit the nut at one end, and tapered to fit the wedge-shaped ring at
the other. The nut is screwed into the hollow plug so as to force the wedge
shaped ring to fit the taper formed inside the plug and the taper formed on the
tube.
Improvements in Steam Generators of the Locomotive Type.
I, WALTER MACKERSIE SMITH, of 16, Otterburn Terrace, Jesmond, 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 has reference to improvements in steam generators of the
locomotive type wherein water tubes are arranged in the fire boxes of such steam
generators so as to connect the water space at one point with that at another
for the purpose of increasing the heating surface and obtaining a better water
circulation than usual, as described for example in the Specification of another
application for Letters Patent filed by me viz. No. 6118 dated 9th March 1897.
According to this invention the water tubes are connected to the fire box
shell by coupling devices so constructed and arranged that the tubes can be
readily connected in a detachable manner to the inner side of the fire box shell
so that they can be readily removed through the. fire door or bottom of the fire
box for examination or other purpose and be replaced or renewed as I shall now
describe with reference to the accompanying illustrative drawings wherein Figs. 1
and 2 are longitudinal sections, Fig. 3 a cross section, and Fig. 4 a sectional
plan showing the fire box portions of a steam generator of the locomotive type
with various arrangements of water tubes secured in place by coupling devices
according to this invention. Figs. 5 to 14 inclusive show several constructions
of coupling devices connecting a tube end to the fire box shell according to this
invention, each construction being shown in end elevation and in a sectional view
in the plane of the longitudinal axis of the coupling device.
1ª, 1, 1º, 1ª, 1º° (Figs. 1 to 4) are water tubes connected to the inner side
of the fire box shell 2 by coupling devices 3 arranged to be operated from within
the fire box, the said tubes being bent and arranged to connect points on the
same side of the fire box as shown at 1" (Figs. 2 and 4); or on opposite sides
as shown at 1b, 1° (Fig. 3); or the sides with the rear end of the fire box as
shown at 1 (Figs. 2 and 4); or the side with the roof as shown at 1.1° (Figs. 1
and 3); or the rear end with roof as shown at 1' (Fig. 2), the tubes in each case
being so arranged as to connect points at different levels and so that ready access
can be gained to the smoke tubes 4 of the boiler as in the arrangements described
in my said former Specification. 5 (Figs. 1 and 3) are guards designed to prevent
direct impact of flame upon the lower coupling devices 3.

page_text: The coupling devices for securing the ends of the tubes in a detachable manner
to the fire box shell may be variously constructed.
Figs. 5 and 6 show one construction of coupling device suitable for this purpose.
It comprises a hollow tapered screw plug or nipple 6 (hereinafter called a plug)
which is screwed tightly into a thickened part 2 of the fire box shell 2 and
projects into the fire box, and a nut 7 which is screwed onto the inwardly project-
ing end of the plug and also onto the adjacent end of the water tube 1 which
is preferably thickened. The thickening may conveniently be done by screwing
onto the tube end a metal ring or sleeve 1 which is screw threaded externally. The
screwed part 6 of the plug projecting into the fire box is made larger in diameter
than the enlarged part 1 of the tube 1, and the pitch of the screw thread thereon
is also made greater than that on the thickened tube end. The two screw threads
on the nut are made the one to fit the plug and the other to fit the thickened
tube end. To fix the tube end in place, the nut is run back on to the tube
which is then placed in position, after which the nut 7 is run forward onto the
plug and screwed up tight. As the screw thread on the plug is coarser than
that on the tube end, the conical end 1" of the tube will be drawn tightly into
or against a conical seat 6" on the plug, thus forming a steam tight joint. By
screwing back the nut, the tube end can be readily detached from the plug and
removed from the fire box, the plug remaining permanently in position.
Figs. 7 and 8 show another construction in which the enlarged tube end 1^
is provided with a collar 1° by which its coned end 1" is forced into close contact
with the coned end 6 of the plug 6 by the flange 7 of the nut 7 which is
screwed onto the projecting end of the plug 6 to fix the tube end in place and
screwed off the plug to detach the tube end. The collar is preferably formed
on a ring or sleeve 1* screwed onto the tube end as shown
Figs. 9 and 10 show another construction in which a nut 8 and a hollow plug 6
is passed over the tube end to which is then secured in a fluid tight manner,
as by brazing, a ferrule or sleeve 1 which is screw threaded at its inner end
as at 1 and is provided at its outer end with a cone 1. The tube end in this
case is fixed in place by passing it through the hole in the thickened part 2°
of the fire box shell after the nut 8 and plug 6 have been moved back on the
tube, then screwing the plug through the hole in the fire box shell until it
bears in a water tight manner against the coned end 12 of the sleeve 1^, and
finally screwing the nut 8 on the sleeve 1 until it bears in a steam tight manner
against the plug. The tube end is detached by reversing these operations.
Figs. 11 and 12 show a modification somewhat like that illustrated in Figs. 9
and 10 except that the plug 6 screws onto the ferrule or sleeve 1 which is
made shorter and is not provided with a nut.
Figs. 13 and 14 show another construction in which the tube end is outwardly
flared or coned and the interior of the plug 6 is inwardly coned, and a ferrule
or ring 9 coned externally and internally to fit the plug and tube end respectively,
is forced into close contact with each of them so as to make a fluid tight joint
with both and hold the tube end in place, by a forcing nut 8* which is screwed
into the plug and bears against the said ferrule or ring. By screwing back
the nut 8, the tube end can be readily detached.
By the constructions shown it will be seen that the water tubes can be readily
fixed in place and detached by the operation of coupling devices located within
the fire box, thereby obviating the necessity of forming holes in the outer shell 2*
of the fire box for gaining access to the tube ends for fixing them in place
and detaching them.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is-
1. In a steam generator of the locomotive type, the combination with the fire
box and water tubes arranged therein as and for the purpose set forth, of coupling

page_text: devices arranged to be operated from within the fire box and whereby the ends of
the tubes can be attached in a readily detachable manner to the inner shell
of the fire box without the aid for this purpose of openings in the outer shell
of the fire box, substantially as herein described.
2. In a steam generator of the locomotive type, the combination with the fire
box and water tubes arranged therein as and for the purpose set forth of coupling
devices comprising hollow plugs screwed into the inner shell of the fire box, and
nuts surrounding the tube ends within the fire box and adapted when screwed
to the plugs to secure the corresponding tube ends to the fire box shell, substan-
tially as described.
3. In a steam generator of the locomotive type, the combination with the fire
box and water tubes arranged therein, of coupling devices constructed, arranged
and operating, substantially as hereinbefore described with reference respectively
to and shown in Figs. 5 and 6; in Figs. 7 and 8; in Figs. 9 and 10; in Figs. 11
and 12 and in Figs. 13 and 14 of the drawings annexed for the purposes specified.
D11
1000
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For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.