Improvements in and relating to the Draught-conduits of Flame- tube-boilers with Superheaters.
Year: 1895

page_text: Date of Application, 15th June, 1895-Accepted, 20th July, 1895
COMPLETE SPECIFICATION.
Improvements in and relating to the Draught-conduits of Flame-
tube-boilers with Superheaters.
I, WILHELM SCHMIDT of Ballenstedt near the Harz, in the Duchy of Anhalt,
German Empire, Civil 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 refers to horizontal boilers, as Cornish-, Lancashire-, Galloway-
and similar boilers, which are provided with one or two flame-tubes extending
through the boiler in the longitudinal direction of the latter, and forming each in
its front part a furnace for said boiler. My improvements in boilers of said kind
relate to the combination of the same with a superheater, and to a special
arrangement of the conduits leading the fire-gases from the flame-tube or tubes to
said superbeater, the purpose being to regulate the degree of superheating without
any loss in the proper exhaustion of said fire-gases.
In order to make my invention more clear, I refer to the accompanying drawing,
in which as an example I have shown my invention applied to a Lancashire-boiler,
and in which similar letters denote similar parts throughout the several views.
Figure 1 is a vertical longitudinal section through said boiler with the
superheater and conduits,
Figure 2 is a horizontal section through the boiler and conduits, and
Figure 3 is a vertical cross-section through said parts.
The flame-tubes a¹ a² of the boiler terminate into a conduit b, which is connected
with the bottom conduit and the vertical conduit 6 by means of the lateral
longitudinal conduits 6 and the lateral vertical conduits 63 64. The conduits b
and are directly connected by a channel 7, which may be closed by a slide d.
If channel is closed, the fire-gases leaving the flame-tubes a¹ a² are compelled to
flow through the conduits 162 63 64 and b, or along over a considerable surface of
the shell of the boiler respectively, whereafter only they are allowed to pass into
the end-conduit 6. If, however, the slide d is in its upper position, the fire-gases
will pass from conduit through the intermediate conduit & directly into said end
conduit 6, and the fire-gases will in this case arrive in the said eud-conduit at a far
higher temperature than in the first-mentioned case.
The superheater consists of a column of horizontal coils c, which latter encompass
a flue c' furnished at its upper end with a flap or cover c². If the latter is open
the fire-gases coming from the conduit 6 will pass through the flue c'; but if said
flap or cover is closed, the fire-gases will pass through the superheater proper, or
around the coils c respectively.
On heating the boiler the flap c² is left open as long as there is no steam passing
through the coils c, so that the latter are prevented from being burnt by the
furnace-gases; the slide d is kept closed during that time.
After the proper
working-pressure is attained, the slide d is opened, and the flap c² closed, so that
the steam now passing through the coils c is superheated by the hot fire-gases
flowing around said coils.
There is by the arrangement of the slide d afforded the possibility of regulating
the degree of superheating without any loss in the proper exhaustion of the
fire-gases, as the latter in my improved boiler are thoroughly exhausted either by
the boiler proper, or by the superheater; the fire-gases are, thus, properly
exhausted in any case. If the degree of superheating is to be lowered, the flap c

page_text: may be partially opened, so as to allow a corresponding part of the hot fire-gases
to escape directly into the chimney, but the slide d is lowered as much as desired
so as to compel a corresponding portion of the furnace-gases to pass through the
conduits 61 62 63 64 and 68 as afore described.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manuer the same is to be performed, I declare that what I
claim is :-
In a flame-tube-boiler having a superheater arranged so as to allow the fire-gases
of said boiler to act on said superheater, the combination with the flues or conduits
adapted to lead the fire-gases from the flame-tubes to the superheater along over
the shell of the boiler proper, of another flue or conduit adapted to divert said
gases from said former flues or conduits, and to lead them directly to the said
superheater; said other flue or conduit having a slide, flap, valve or equivalent
organ adapted to narrow or close the said other flue, for the purpose as described.
Dated this 15th day of June 1895.
WILHELM SCHMIDT,
By Geo. Thos. Hyde,
Agent for the Applicant.