AN IMPROVED STEAM BOILER
Year: 1885

page_text: BENJAMIN HOWARTH THWAITE Civil Engineer and Consulting Chemist Dart-
mouth Villa Fountain St Tranmere Cheshire do hereby declare the nature of my
invention for AN IMPROVED STEAM BOILER to be as follows:-
I construct the boiler with a large central flue-at least half the diameter of the
steam boiler proper, this central flue I line internally with refractory tiles. I place
this central flue immediately over the combustion zone chamber of my patent gas
producer-see patent No 4 1885. The great capacity and diameter of this central
flue permits the unimpeded action of gaseous combustion and permits the most
complete radiation of the heat from the incandescent atoms of carbon, the fireclay
or refractory lining has the effect of producing the licking action of the flame that
is to say the flame flows in close contact to the fireclay or refractory lining when
that is heated to incandescence, and this prevents the deposition of any solid and
unconsumed carbon, This central flue is in the centre of a nest of tubes, the heated
gases after ascending through the central flue descend through the tubes but before
the heated gases enter the upper end of the tubes, I cause them to traverse through
what I term a heat accumulator which consists of a nest of checker brickwork and
which I construct immediately over the upper opening of the central flue.
The heated gases give part of their heat up to this brickwork in traversing the
numerous openings through it until it becomes heated to incandescence and aids in
fixing the volatile gases and prevents the deposition of carbon or tarry matter on
the tube plates and tubes and also produces a more equable action of heat trans-
mission to the water.
The heated gases after descending through the tubes are compelled to pass over
the air recuperator tubes (see my patent No 4, 1885, Gas producer and boiler
furnace) to which they give up a great part of their heat, which is afterwards
transmitted to the air flowing to support combustion.
In order to produce a rapid circulation of the water I provide a diaphram plate
in the tubular part of the steam generator, placed midway all round between the
central flue and the outer plates but having a space under its lower edge for the
passage of the water under it. The water will then descend on the outside of
the diaphram plate passing under it sweeping the lower tube plate in its passage
and then ascending sweeping the sides of the central flue.
The upper flue chamber of the steam generator containing the heat accumulator
I make sufficiently deep to allow the entrance into it of a man to examine and
clean the tubes, over this chamber I construct the steam dome, which I connect
with the lower or tubular part by means of an annular water space surrounding
and enclosing the flue chamber.

page_text: I, BENJAMIN HOWARTH THWAITE Civil Engineer and Consulting Chemist,
23 Fountain St, Tranmere Cheshire do hereby declare the nature of my inven-
tion for AN IMPROVED STEAM BOILER and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
My improvement consists as follows, immediately over my gas producer, patent
No 4, 1885, I construct a circular or square or hexagonal framework or base
supporting the steam generator.
This framework carries the supplementary recuperator air tubes, and also forms
the flue for leading the products of combustion into the chimney, the recuperator
tubes may either be of refractory earthenware or of metal.
I make the framework hose in segments one of which I make movable in order
that it may be withdrawn for the purpose of renewing the burner tubes.
I construct the boiler with a large central flue at least half the diameter of the
steam boiler proper-this I line with refractory tiles perforated with holes. I place
this combustion flue immediately over the combustion zone chamber.
The great capacity and diameter of the flue permits the unimpeded action of
gaseous combustion to ensue, and the most complete radiation of the heat from the
incandescent atoms of carbon which issue from the zone of hydro-oxidation or of
the combustion.
The fireclay or refractory lining of the central combustion flue has the effect of
producing the licking action of the flame, that is to say the flame flows in close
contact with the perforated fireclay lining when that is heated to incandescence,
and this prevents the deposition of any solid and unconsumed carbon-This
combustion flue is in the centre of a nest of tubes, the heated gases after issuing
from the summit or upper end of central combustion flue descend through the tubes
but before the heated gases enter the upper end of the tubes I cause them to
traverse through what I term a heat accumulator, formed by a nest of chequer
brickwork which I construct immediately over the upper opening of the central
combustion flue, the heated gases give up part of their heat to the brickwork in
passing through it, until the brickwork attains the heat of incandescence, and it
then aids in fixing the volatile gases and prevents the deposition of carbon or tarry
matter on the boiler plates and tubes and also produces a more equable action of
heat transmission to the water.
The heated gases after descending through the tubes are compelled to pass over
the air recuperator tubes to which they give up a great part of their heat which is
in its turn transmitted to the air flowing to support combustion.
In order to promote a rapid circulation of the water I provide a diaphram plate
in the tubular part of the steam generator all round and placed midway between
the central flue and the outer plates but having a space or distance between its
lower edge and the lower tube plate for the passage of the water under it.
The water mill then descend on the outside of the diaphram plate passing under
it and sweeping over the lower tube plate it will then ascend sweeping the surface
of the central flue plate.

page_text: 3rd Providing a heat accumulator chamber at the end of the combustion flue
substantially as described.
4th Providing a diaphram plate for inducing circulation or flow of water substan
tially as described.
5th The chimney arrangement for inducing draught substantially as described in
its application to my form of steam generator.
6th The general arrangement of steam generator substantially as described.
7th The combination of this Invention with my patent No 4, 1885.
Dated this 26th day of Sentember 188k
B. H. THWAITE.