Improvements in the Drying or Superheating of Steam, and Apparatus therefor.
Year: 1891

page_text: Date of Application, 3rd Apr., 1891
Complete Specification Left, 4th Jan., 1892-Accepted, 20th Feb., 1892
Improvements in the Drying or Superheating of Steam, and
Apparatus therefor.
I, THOMAS MUDD of Central Engine Works, West Hartlepool, in the County
of Durham, Engineer, do hereby declare the nature of this invention to be as
follows:-
The superheating of steam for engines has in the past been attempted by passing
the whole of the steam through heated pipes or chambers, and, whilst there was an
admitted large economy, failure always followed from the mechanical difficulties
involved, and which arose owing to the want of control over the superheater, so as
to be able to adjust it to such a point as would secure the economy without
deteriorating the rubbing surfaces.
To effect this, I propose to leave the main supply of moist steam from the boiler
to the engine undisturbed. To dry this steam as it enters the engine, I fix a
separate and generally a smaller stop valve on the boiler, from which I take a series
of pipes, bulbs or vessels of various forms, fixing the same within the smoke box,
and leading a pipe from the same to the point where the main steam enters the
engine. At this point I fix another stop valve. By these means, I can cause a
certain quantity of steam to be passed through the superheating pipes or bulbs
within the smoke box raising it there to a higher temperature than that due to its
pressure, and, by admitting as much or as little as I please of this dry and super-
heated steam into the engine valve chest together with the moist steam coming from
the main steam pipe, I can raise the general temperature of the whole of the steam
to dryness, or to any degree of superheat that the rubbing surfaces of the engine will
stand, the same being perfectly under control, and capable of being shut off
altogether at any moment, without stopping the engine.
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If I find the temperature of the waste gases at the smoke box insufficient for my
purpose without involving greater heating surface in the superheater than I desire,
propose to effect the same end as above described, either by passing the super-
heating steam through tubes, coils or bulbs that are independently heated, or by
taking the superheating steam from a small separate boiler, preferably of the
"water tube type, and which would preferably be worked at a much higher
pressure than the main boiler, thus rather effecting the drying of the main steam
by expansion down to its pressure than by superheat in the true sense. In any case,
it would simply be an addition to the ordinary arrangements, and could be admitted
or cut out at any time without interfering with the progress of the work in hand
done by the engine.
WM. P. THOMPSON & Co.,
Per John Hayes,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Drying or Superheating of Steam, and
Apparatus therefor.
I, THOMAS MUDD of Central Engine Works, West Hartlepool, in the County
of Durham, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
The superheating of steam or engines has in the past been attempted by passing

page_text: the whole of the steam through heated pipes or chambers, and, whilst there was an
admitted large economy, failure always followed from the mechanical difficulties
involved, and which arose owing to the want of control over the superheat, so as to
be able to adjust it to such a point as would secure the economy without
deteriorating the rubbing surfaces.
To effect this, I propose to leave the main supply of moist steam from the boiler
to the engine undisturbed, superheat another portion and unite the two near the
point where they are used.
Referring to the drawings-
Figure is a plan of an apparatus for this purpose showing boilers and steam
chest.
Figure 2 side elevation of same-showing also boiler uptake and steam. chest.
Figure 3 enlarged view of three sections of the superheater of Figure 1, and
Figures 4, 5 and 6 enlarged views of other varieties of heater section.
Like letters signify like parts in all the figures.
Referring more especially to Figure 1-
1 is a stop valve on one of the boilers admitting steam through pipe 2 into a row
of pipes or small vessels 3 fixed inside the smoke box just above the top row of
tubes. The steam becomes dried and superheated by the heat received from the
waste gases in passing through the tortuous passages formed by these pipes or
vessels and is conveyed by pipe 4 to a branch on the main stop valve 5 of the main
engine, where the dried steam is admitted by another stop valve 6 (see side eleva-
tion) and mixes with the saturated steam coming to the main stop valve through the
ordinary main steam pipe in the usual way.
7 (Figure 1) is a safety valve placed midway in the row of sectional heaters so as
to relieve any excessive pressure that may arise.
The mode of action is as follows-
The steam entering the sectional heaters 3 is superheated by the heat of the
waste gases and entering the main steam pipe at once dries the wet steam by giving
up its own superheat, the supply of superheated steam being regulated by stop
valve 6, Figure 2. The above is one form of my apparatus applicable for marine
purposes, it being obvious, however, that the idea of superheating a regulated
portion only of the steam can be applied to almost any purpose where dry steam is
required, and even in steam engines its use can be twofold, a part being employed
to dry the steam used inside the cylinders and the other part utilised in steam
jackets to heat the same to a point above the temperature of the working steam
inside the cylinder. It is obvious too that the sections of the superheater can be of
endless variety of forms such as spirals, tubes, bulbs and the like. Instead too of
locating them in the uptake a special furnace could be used as superheater or the
coils could be placed in the flue of furnace itself with suitable precautions.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is―
1. The method of drying or superheating steam which consists in superheating a
portion of the steam only and adding it to the main body of working steam
before use.
2. The special apparatus as a whole for drying or superheating the steam to a
regulated degree, so that the extent of the drying or superheating shall be entirely
under control, substantially as described.
Dated the let dox of
Lanuary
ERD
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.