Improvements in Steam Generators.
Year: 1896

page_text: Date of Application, 29th Feb., 1895
Complete Specification Left, 29th Dec., 1896-Accepted, 27th Feb., 1897
Improvements in Steam Generators.
I, OTTO FREDERICK VOLLHARD of the Metropolitan Works, Oldfield Road,
Salford in the County of Lancaster, Fire Engine and Hose Manufacturer, do
hereby declare the nature of this invention to be as follows:-
This invention relates to steam generators intended for use where the conditions
of light weight and rapid evaporation are essential, or, in other words, where there
must be in the generator, a maximum heating surface in a minimum space, with
adequate circulation of the water, and my object is the design and construction
of such a generator which may be cheaply manufactured, be free from intricacies,
and have no considerable volume of water not acted upon directly by heat from
the fire.
In carrying out my invention employ a longitudinal steam chamber and,
at the plane of the furnace bars, two tubular mud chambers between which the
fire-bars are arranged. At the ends of the said chambers there are two vertical
parallel chambers, one at each end, to which the steam chambers and the mud
chombers respectively are connected so that the end chambers are in communi-
cation with each other through the steam and mud chambers. The furnace door
opening is formed through one of the end chambers.
The end chambers are also in communication with each other through a series
of tubes exposed to the heat of the fire and to the hot gases arising therefrom.
These tubes may be horizontal, or, if preferred, slightly out of the horizontal to
promote circulation and to prevent accumulation of steam therein.
A serried series of pipes connects each mud chamber with the lower arc of
the steam chamber, preferably rising vertically from the mud chamber, and bent
and re-curved to join the steam chamber. These two series of pipes thus form
the side walls of the fire-box, the end walls of which are constituted by the end
chambers.
If the pipes connecting the mud chambers with the steam chamber are joined
to the latter in straight lines, there will be no sufficient escape for the products
of combustion from the fire. To provide this means of escape, I make the
junctions of these pipes break pitch with each other, that is to say, for example,
if the first pipe is joined at the bottom of the steam chamber, the third of
the same series is joined nearer to the water level and the second, on an
intermediate line, diagonal passages for the gases being thus produced.
The fire-box may be surrounded by a metallic casing in communication with
the flue or chimney.
Daied this 28th dow of Fa
D 1900
W. E. HEYS & SON,
Agents for the Applicant.

page_text: Improvements in Steam Generators.
1, OTTO FREDERICK VOLLHARD of the Metropolitan Works. Oldfield Road,
Sallord in the County of Lancaster, Fire Engine and Hose Manufacturer, 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 steam generators which are especially designed for use
where the conditions of light weight and rapid evaporation are essential; or, in
other words, where there must be in the generator, a maximum heating surface in
a minimum space with adequate circulation of the water and my principal objecte
are the design and construction of such a generator which may be cheaply
constructed, be free from intricacies, and have no large volume of water which
is not acted upon directly by the heat from the fire.
A steam generator constructed according to this invention is provided with a
suitable stenm chamber, and, at about or below the level of the fire-bars, with a
mud chamber or mud chambers. The mud chamber or chambers is or are
connected with the steam chamber by means of a series of pipes which are so
arranged and disposed as to form side walls of the fire box. The end walls of the
fire-box are formed by two end chambers which are also in communication with the
stenm chamber and the mud chamber or chambers respectively. The furnace door
opening is formed through the front end chamber and both of the end chambers
are in con inunication with each other through a series of horizontal or diagonal
connecting pipes which are fully exposed to the heat from the fire. It is preferred
that there pipes should be inclined to promote circulation and to prevent the
accumulation of steam therein.
In order that my invention may be more readily understood and carried into
practical effect, I have appended three sheets of drawings herete, to which
reference will hereinafter be made. In each of the figures of these drawings,
similar parts are denoted by similar letters of reference.
Figure represents a vertical cross section, looking to the front; Figure 2,
a vertical longitudinal section; Figure 3, a vertical cross section looking to the
back and Figures 4 to 8 inclusive, details.
Figures 9 and 10 shew vertical sections at right angles to each other, of part of
a steam generator having a single mud chamber.
Figure 11 represents a cross section, and Figure 12 a partial sectional elevation
of the mud chamber Figure 9, drawn to an enlarged scale.
Referring to the construction illustrated by Figures 1, 2 and 3, A indicates the
steam chamber which is connected with the mud chambers C by means of the side
tubes B. The steam chamber and the mud chambers all open at their ends into
the vertical end chambers E F, and these end chambers are also in communication
with each other through the series of cross connecting tubes G. The side tubes B
are arranged as closely together as is practicable so as to form side walls for the
fire-box. To facilitate this, as well as to form openings for the escape of the
products of combustion around the steam chamber, the ends of the tubes B are su
bent as to make junction along two lines on the mud and the steamn chambers
respectively, as illustrated by Figure 1. Alternate tubes make junction on
different lines so that the joints break pitch with each other.
Euch end chamber E F, is formed by two parallel plates which are kept apart
and supported by the packing frames H, which form the edges of the chambers and
by the gauge studs J. The furnace door opening K is similarly supported and
cuclosed bby a ring or frame L. The cross tubes Genter holes in the inner plates

page_text: of the chambers E F and are expanded or otherwise suitably secured in place as is
well understood. The steam outlet may he arranged at front or at the back of the-
boiler as indiented at M, Figures 1 and 2, but preferably at the back as shewn by
Figure 2. A baffle plate N, may advantageously be arranged as shewn by
Figure 2, to prevent undue surging of the water. The generator is provided with
lateral and overhead casing P, and the funnel or chimney Q.
In Figure 4, the two ends of one of the mud chambers are shewn on an enlarged
scale to illustrate one method of attaching them to the inner plates of the end.
chambers. According to this method, one end of the mud chamber is made with.
a slightly larger external diameter than the other and each end is screwed with
a thread of similar pitch. The inner walls of the end chambers are corre-
spondingly bored and internally screwed for their reception. The smaller end of
the steam chamber, before the end chambers are closed, is passed through the
larger hole in one of the end walls and is brought against the hole in the other
end wall prepared for its reception. The larger end of the mud chamber is now in
contact with the screwed hole in its appropriate plate. The chamber being now
rotated, its screwed and enter the plates and make joint. The end of the chambers
may be arranged to project sufficiently to be flanged over, if desired.
The lower ends of the side tubes B may be connected to the mud chambers by
various devices. As illustrated by Figure A, the end of each pipe B is screwed to
engage internally with a thimble a, which has a diminished end externally screwed
with a thread of opposite direction. The drum is bared with holes along two lines,.
tapped for the reception of the thimble. For each thimble there is a washer
having its underside hollowed to fit the curvature of its seating. In securing a
tube in its place, the end of the thimble is passed through the washer & and is
entered into its hole in the mud chamber. The tube B is then entered into its
thimble which is then rotated. Because of the opposite direction of the screw
threads, the rotation of the thimble causes the latter to fully enter the mud
chamber, and the tube to fully enter the thimble at the same time. A tight joint
is secured, when desired, by a nut-lock such as c. The upper ends of the tubes
may be sprung into place in their holes in the steam chamber and be expanded or
otherwise secured.
Figures 7 and 8 illustrate part of the packing frame I at the edges of the
vertical chambers.
Figures 9 to 12 inclusive illustrate a modified construction of the lower part of
the generator. A central mud chamber is substituted for the two lateral chambers,
and the side tubes B are returned below the fire-box and make joint with it on each
side, breaking pitch as hereinbefore described and as indicated by Figures 11
and 12. The tubes B are by preference attached to the mud chamber before the
latter is connected with the end chambers E F. As rotation of the mud chamber
is thus impracticable, its joints with the end chambers may be made as shewn by
Figure 12. The two ends of the mud chamber are slightly coned, and the
openings for their reception formed in the inner walls of the end chambers are
correspondingly coned. When the mud chamber has been fitted in place, a stay
bolt R is passed through the end chambers and the mul chamber, axially, and is
screwed up. The walls around the openings in the end chambers are kept apart
by the packing rings or frames H and L.
A steam generator constructed as described with reference to Figures 9 to 12, is.
particularly adapted to be heated by means of liquid fuel, in which case the
returned parts of the tubes B may be used as a temporary Hoor for a wood fire
whilst getting up the bead of steam required to feed the liquid fuel.
The modified form of mud drum may be used in substitution for the form.
illustrated by Figures I and 2, with a ccnsequent modification in the positions of
the openings for the pipes B.
It will be observed that the steam chamber A forms part of the general
circulatory system, and that to facilitate this circulation, the upper ends of the
tubes B open therein alteruately above and below the normal water level.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
In a steam generator of the type set forth, the combination and arrangement.
of a steam chamber, one or more mud chambers, side tubes connecting the steam
chamber with the mud chamber or chambers and forming lateral walls, vertical
end chambers, and longitudinal tubes connecting the end chambers, constructed
substantially as hereinbefore described and as illustrated by the accompanying
drawings.
Dated this 8th day of
W. E. HEYS & SON,
Agents for the Applicant.